azul_layout/solver3/fc.rs
1//! Formatting context layout (block, inline, table, and flex/grid via Taffy)
2
3use std::{
4 collections::{BTreeMap, HashMap},
5 sync::Arc,
6};
7
8use azul_core::{
9 dom::{FormattingContext, NodeId, NodeType},
10 geom::{LogicalPosition, LogicalRect, LogicalSize},
11 resources::RendererResources,
12 styled_dom::{StyledDom, StyledNodeState},
13};
14use azul_css::{
15 css::CssPropertyValue,
16 props::{
17 basic::{
18 font::{StyleFontStyle, StyleFontWeight},
19 pixel::{DEFAULT_FONT_SIZE, PT_TO_PX},
20 ColorU, PhysicalSize, PropertyContext, ResolutionContext, SizeMetric,
21 },
22 layout::{
23 ColumnCount, ColumnWidth, LayoutBorderSpacing, LayoutClear, LayoutDisplay, LayoutFloat,
24 LayoutHeight, LayoutJustifyContent, LayoutOverflow, LayoutPosition, LayoutTableLayout,
25 LayoutTextJustify, LayoutWidth, LayoutWritingMode, ShapeInside, ShapeOutside,
26 StyleBorderCollapse, StyleCaptionSide, StyleEmptyCells,
27 },
28 property::CssProperty,
29 style::{
30 BorderStyle, StyleDirection, StyleHyphens, StyleLineBreak, StyleListStylePosition,
31 StyleListStyleType, StyleOverflowWrap, StyleTextAlign, StyleTextAlignLast,
32 StyleTextBoxTrim, StyleTextCombineUpright, StyleTextOrientation, StyleUnicodeBidi,
33 StyleVerticalAlign, StyleVisibility, StyleWhiteSpace, StyleWordBreak,
34 },
35 },
36};
37use rust_fontconfig::FcWeight;
38use taffy::{AvailableSpace, LayoutInput, Line, Size as TaffySize};
39
40#[cfg(feature = "text_layout")]
41use crate::text3;
42use crate::{
43 debug_ifc_layout, debug_info, debug_log, debug_table_layout, debug_warning,
44 font_traits::{
45 ContentIndex, FontLoaderTrait, ImageSource, InlineContent, InlineImage, InlineShape,
46 LayoutFragment, ObjectFit, ParsedFontTrait, SegmentAlignment, ShapeBoundary,
47 ShapeDefinition, ShapedItem, Size, StyleProperties, StyledRun, TextLayoutCache,
48 UnifiedConstraints,
49 },
50 solver3::{
51 geometry::{BoxProps, EdgeSizes, IntrinsicSizes},
52 getters::{
53 get_css_border_bottom_width, get_css_border_top_width,
54 get_css_height, get_css_padding_bottom, get_css_padding_top,
55 get_css_width, get_direction_property, get_unicode_bidi_property,
56 get_display_property, get_element_font_size, get_float, get_clear,
57 get_list_style_position, get_list_style_type, get_overflow_x, get_overflow_y,
58 get_parent_font_size, get_root_font_size, get_style_properties,
59 get_text_align, get_text_box_trim_property, get_text_orientation_property,
60 get_vertical_align_property, get_visibility, get_white_space_property,
61 get_writing_mode, MultiValue,
62 },
63 layout_tree::{
64 AnonymousBoxType, CachedInlineLayout, LayoutNode, LayoutNodeHot, LayoutNodeWarm, LayoutNodeCold, LayoutTree, PseudoElement,
65 },
66 positioning::get_position_type,
67 scrollbar::ScrollbarRequirements,
68 sizing::extract_text_from_node,
69 taffy_bridge, LayoutContext, LayoutDebugMessage, LayoutError, Result,
70 },
71 text3::cache::{AvailableSpace as Text3AvailableSpace, TextAlign as Text3TextAlign},
72};
73
74/// Default scrollbar width in pixels (CSS `scrollbar-width: auto`).
75/// This is only used as a fallback when per-node CSS cannot be queried.
76/// Prefer `getters::get_layout_scrollbar_width_px()` for per-node resolution.
77pub const DEFAULT_SCROLLBAR_WIDTH_PX: f32 = 16.0;
78
79// Note: DEFAULT_FONT_SIZE and PT_TO_PX are imported from pixel
80
81/// Result of BFC layout with margin escape information
82#[derive(Debug, Clone)]
83pub(crate) struct BfcLayoutResult {
84 /// Standard layout output (positions, overflow size, baseline)
85 pub output: LayoutOutput,
86 /// Top margin that escaped the BFC (for parent-child collapse)
87 /// If Some, this margin should be used by parent instead of positioning this BFC
88 pub escaped_top_margin: Option<f32>,
89 /// Bottom margin that escaped the BFC (for parent-child collapse)
90 /// If Some, this margin should collapse with next sibling
91 pub escaped_bottom_margin: Option<f32>,
92}
93
94impl BfcLayoutResult {
95 pub fn from_output(output: LayoutOutput) -> Self {
96 Self {
97 output,
98 escaped_top_margin: None,
99 escaped_bottom_margin: None,
100 }
101 }
102}
103
104/// The CSS `overflow` property behavior.
105#[derive(Debug, Clone, Copy, PartialEq, Eq)]
106pub enum OverflowBehavior {
107 Visible,
108 Hidden,
109 Clip,
110 Scroll,
111 Auto,
112}
113
114impl OverflowBehavior {
115 pub fn is_clipped(&self) -> bool {
116 matches!(self, Self::Hidden | Self::Clip | Self::Scroll | Self::Auto)
117 }
118
119 pub fn is_scroll(&self) -> bool {
120 matches!(self, Self::Scroll | Self::Auto)
121 }
122}
123
124/// Input constraints for a layout function.
125#[derive(Debug)]
126pub struct LayoutConstraints<'a> {
127 /// The available space for the content, excluding padding and borders.
128 pub available_size: LogicalSize,
129 /// The CSS writing-mode of the context.
130 pub writing_mode: LayoutWritingMode,
131 /// Full writing mode context (writing-mode + direction + text-orientation).
132 /// Used by writing-mode-aware layout code to correctly map inline/block
133 /// dimensions to physical x/y coordinates.
134 pub writing_mode_ctx: super::geometry::WritingModeContext,
135 /// The state of the parent Block Formatting Context, if applicable.
136 /// This is how state (like floats) is passed down.
137 pub bfc_state: Option<&'a mut BfcState>,
138 // Other properties like text-align would go here.
139 pub text_align: TextAlign,
140 /// The size of the containing block (parent's content box).
141 /// This is used for resolving percentage-based sizes and as parent_size for Taffy.
142 pub containing_block_size: LogicalSize,
143 /// The semantic type of the available width constraint.
144 ///
145 /// This field is crucial for correct inline layout caching:
146 /// - `Definite(w)`: Normal layout with a specific available width
147 /// - `MinContent`: Intrinsic minimum width measurement (maximum wrapping)
148 /// - `MaxContent`: Intrinsic maximum width measurement (no wrapping)
149 ///
150 /// When caching inline layouts, we must track which constraint type was used
151 /// to compute the cached result. A layout computed with `MinContent` (width=0)
152 /// must not be reused when the actual available width is known.
153 pub available_width_type: Text3AvailableSpace,
154}
155
156/// Manages all layout state for a single Block Formatting Context.
157/// This struct is created by the BFC root and lives for the duration of its layout.
158#[derive(Debug, Clone)]
159pub struct BfcState {
160 /// The current position for the next in-flow block element.
161 pub pen: LogicalPosition,
162 /// The state of all floated elements within this BFC.
163 pub floats: FloatingContext,
164 /// The state of margin collapsing within this BFC.
165 pub margins: MarginCollapseContext,
166}
167
168impl BfcState {
169 pub fn new() -> Self {
170 Self {
171 pen: LogicalPosition::zero(),
172 floats: FloatingContext::default(),
173 margins: MarginCollapseContext::default(),
174 }
175 }
176}
177
178/// Manages vertical margin collapsing within a BFC.
179#[derive(Debug, Default, Clone)]
180pub struct MarginCollapseContext {
181 /// The bottom margin of the last in-flow, block-level element.
182 /// Can be positive or negative.
183 pub last_in_flow_margin_bottom: f32,
184}
185
186/// The result of laying out a formatting context.
187#[derive(Debug, Default, Clone)]
188pub struct LayoutOutput {
189 /// The final positions of child nodes, relative to the container's content-box origin.
190 pub positions: BTreeMap<usize, LogicalPosition>,
191 /// The total size occupied by the content, which may exceed `available_size`.
192 pub overflow_size: LogicalSize,
193 // +spec:inline-formatting-context:f7eebb - baseline along inline axis for glyph alignment
194 /// The baseline of the context, if applicable, measured from the top of its content box.
195 pub baseline: Option<f32>,
196}
197
198/// Text alignment options
199#[derive(Debug, Clone, Copy, Default)]
200pub enum TextAlign {
201 #[default]
202 Start,
203 End,
204 Center,
205 Justify,
206}
207
208/// Represents a single floated element within a BFC.
209#[derive(Debug, Clone, Copy)]
210struct FloatBox {
211 /// The type of float (Left or Right).
212 kind: LayoutFloat,
213 /// The rectangle of the float's content box (origin includes top/left margin offset).
214 rect: LogicalRect,
215 /// The margin sizes (needed to calculate true margin-box bounds).
216 margin: EdgeSizes,
217}
218
219/// Manages the state of all floated elements within a Block Formatting Context.
220// +spec:block-formatting-context:a4e6f9 - float rules reference only elements in the same BFC (scoped via BfcState)
221// +spec:floats:2fa329 - Float positioning (left/right shift), content flow along sides, and clear property
222/// +spec:floats:970b4c - Implements CSS2§9.5 float positioning and flow interaction
223#[derive(Debug, Default, Clone)]
224pub struct FloatingContext {
225 /// All currently positioned floats within the BFC.
226 pub floats: Vec<FloatBox>,
227}
228
229impl FloatingContext {
230 /// Add a newly positioned float to the context
231 pub fn add_float(&mut self, kind: LayoutFloat, rect: LogicalRect, margin: EdgeSizes) {
232 self.floats.push(FloatBox { kind, rect, margin });
233 }
234
235 // +spec:box-model:0c9b13 - line boxes next to floats are shortened to make room
236 // +spec:floats:148fcd - floating boxes reduce available line box width between containing block edges
237 // +spec:floats:49a491 - Line boxes stacked with no separation except float clearance, never overlap
238 // +spec:floats:8974e6 - text flows into vacated space by narrowing line boxes around floats
239 // +spec:floats:af94f2 - content displaced by float: line boxes shrink to avoid float margin boxes
240 // +spec:floats:e5961b - remaining text flows into vacated space via available_line_box_space
241 // +spec:inline-formatting-context:7cbe58 - shortened line boxes due to floats; shift down if too small
242 /// Finds the available space on the cross-axis for a line box at a given main-axis range.
243 // +spec:containing-block:4b0c44 - line boxes shortened by floats resume containing block width after float
244 ///
245 /// Returns a tuple of (`cross_start_offset`, `cross_end_offset`) relative to the
246 /// BFC content box, defining the available space for an in-flow element.
247 // +spec:inline-formatting-context:e70328 - line box width reduced by floats between containing block edges
248 pub fn available_line_box_space(
249 &self,
250 main_start: f32,
251 main_end: f32,
252 bfc_cross_size: f32,
253 wm: LayoutWritingMode,
254 ) -> (f32, f32) {
255 let mut available_cross_start = 0.0_f32;
256 let mut available_cross_end = bfc_cross_size;
257
258 for float in &self.floats {
259 // Get the logical main-axis span of the existing float's MARGIN BOX.
260 let float_main_start = float.rect.origin.main(wm) - float.margin.main_start(wm);
261 let float_main_end = float_main_start + float.rect.size.main(wm)
262 + float.margin.main_start(wm) + float.margin.main_end(wm);
263
264 // Check for overlap on the main axis.
265 if main_end > float_main_start && main_start < float_main_end {
266 // CSS 2.2 § 9.5: border box must not overlap MARGIN BOX of floats,
267 // so we include the float's margins in the cross-axis bounds.
268 let float_cross_start = float.rect.origin.cross(wm) - float.margin.cross_start(wm);
269 let float_cross_end = float_cross_start + float.rect.size.cross(wm)
270 + float.margin.cross_start(wm) + float.margin.cross_end(wm);
271
272 // +spec:floats:17a63f - float left/right map to line-left/line-right via logical coords
273 // +spec:writing-modes:e55820 - line-relative mappings: left/right interpreted as line-left/line-right per writing mode
274 if float.kind == LayoutFloat::Left {
275 // "line-left", i.e., cross-start
276 available_cross_start = available_cross_start.max(float_cross_end);
277 } else {
278 // Float::Right, i.e., cross-end
279 available_cross_end = available_cross_end.min(float_cross_start);
280 }
281 }
282 }
283 (available_cross_start, available_cross_end)
284 }
285
286 // +spec:block-formatting-context:d06e6e - clearance computation for clear property on blocks and floats (CSS 2.2 § 9.5.2)
287 // +spec:floats:31a3d5 - Clearance computation: places border edge even with bottom outer edge of lowest float to be cleared
288 // +spec:floats:f9bef1 - clear property moves element below preceding floats
289 /// Returns the main-axis offset needed to be clear of floats of the given type.
290 // +spec:block-formatting-context:7f6bde - CSS 2.2 § 9.5.2 clear property: clearance places border edge below bottom outer edge of cleared floats
291 // +spec:block-formatting-context:ef493f - clearance computation: places border edge even with bottom outer edge of lowest float to be cleared; inhibits margin collapsing
292 // +spec:box-model:b118fe - top border edge must be below bottom outer edge of earlier floats
293 // +spec:floats:415066 - Clear property: top border edge below bottom outer edge of cleared floats
294 // +spec:floats:7e4ad6 - clear property: element box may not be adjacent to earlier floats; only considers floats in same BFC
295 // +spec:floats:32e45d - clear:right causes sibling to flow below right floats
296 // +spec:floats:7f417a - clear property prevents content from flowing next to floats
297 // +spec:floats:d06304 - clear property moves element below floats, leaving blank space
298 // +spec:overflow:1a7aff - clearance calculation (incl. negative clearance) and clear on floats (constraint #10)
299 // +spec:positioning:1c2508 - clearance calculation: places border edge even with bottom outer edge of lowest cleared float (CSS 2.2 § 9.5.2)
300 // +spec:positioning:fe0912 - clearance computation: places border edge below bottom outer edge of cleared floats
301 // (clearance = amount to place border edge even with bottom outer edge of lowest
302 // float to be cleared); clearance can be negative per spec example 2
303 // +spec:floats:054a1e - Clearance computation: positions border edge below bottom outer edge of cleared floats
304 // +spec:floats:cb984c - Clearance can be negative per spec example 2; inhibits margin collapsing
305 pub fn clearance_offset(
306 &self,
307 clear: LayoutClear,
308 current_main_offset: f32,
309 wm: LayoutWritingMode,
310 ) -> f32 {
311 let mut max_end_offset = 0.0_f32;
312
313 let check_left = clear == LayoutClear::Left || clear == LayoutClear::Both;
314 let check_right = clear == LayoutClear::Right || clear == LayoutClear::Both;
315
316 for float in &self.floats {
317 let should_clear_this_float = (check_left && float.kind == LayoutFloat::Left)
318 || (check_right && float.kind == LayoutFloat::Right);
319
320 if should_clear_this_float {
321 // CSS 2.2 § 9.5.2: "the top border edge of the box be below the bottom outer edge"
322 // Outer edge = margin-box boundary (content + padding + border + margin)
323 let float_margin_box_end = float.rect.origin.main(wm)
324 + float.rect.size.main(wm)
325 + float.margin.main_end(wm);
326 max_end_offset = max_end_offset.max(float_margin_box_end);
327 }
328 }
329
330 if max_end_offset > current_main_offset {
331 max_end_offset
332 } else {
333 current_main_offset
334 }
335 }
336}
337
338/// Encapsulates all state needed to lay out a single Block Formatting Context.
339struct BfcLayoutState {
340 /// The current position for the next in-flow block element.
341 pen: LogicalPosition,
342 floats: FloatingContext,
343 margins: MarginCollapseContext,
344 /// The writing mode of the BFC root.
345 writing_mode: LayoutWritingMode,
346}
347
348/// Result of a formatting context layout operation
349#[derive(Debug, Default)]
350pub struct LayoutResult {
351 pub positions: Vec<(usize, LogicalPosition)>,
352 pub overflow_size: Option<LogicalSize>,
353 pub baseline_offset: f32,
354}
355
356// Entry Point & Dispatcher
357
358/// Main dispatcher for formatting context layout.
359///
360/// Routes layout to the appropriate formatting context handler based on the node's
361/// `formatting_context` property. This is the main entry point for all layout operations.
362///
363/// # CSS Spec References
364/// - CSS 2.2 § 9.4: Formatting contexts
365/// - CSS Flexbox § 3: Flex formatting contexts
366/// - CSS Grid § 5: Grid formatting contexts
367// +spec:block-formatting-context:b04653 - dispatches layout by formatting context type (BFC, IFC, Table, Flex, Grid)
368// +spec:block-formatting-context:e46499 - inner display type determines formatting context (BFC, IFC, table, flex, grid)
369pub fn layout_formatting_context<T: ParsedFontTrait>(
370 ctx: &mut LayoutContext<'_, T>,
371 tree: &mut LayoutTree,
372 text_cache: &mut crate::font_traits::TextLayoutCache,
373 node_index: usize,
374 constraints: &LayoutConstraints,
375 float_cache: &mut HashMap<usize, FloatingContext>,
376) -> Result<BfcLayoutResult> {
377 let node = tree.get(node_index).ok_or(LayoutError::InvalidTree)?;
378
379 debug_info!(
380 ctx,
381 "[layout_formatting_context] node_index={}, fc={:?}, available_size={:?}",
382 node_index,
383 node.formatting_context,
384 constraints.available_size
385 );
386
387 // +spec:block-formatting-context:06a24f - CSS 2.2 § 9.4: block-level boxes → BFC, inline-level → IFC
388 // +spec:block-formatting-context:9428cf - block container can establish both BFC and IFC simultaneously
389 // +spec:inline-formatting-context:8bfe73 - display:flow generates inline box (Inline) or block container (Block) based on outer display type
390 match node.formatting_context {
391 FormattingContext::Block { .. } => {
392 layout_bfc(ctx, tree, text_cache, node_index, constraints, float_cache)
393 }
394 // +spec:inline-formatting-context:a180ed - IFC establishment: inline-level boxes fragmented into line boxes with baseline alignment
395 FormattingContext::Inline => layout_ifc(ctx, text_cache, tree, node_index, constraints)
396 .map(BfcLayoutResult::from_output),
397 FormattingContext::InlineBlock => {
398 // +spec:display-property:1f5ddf - inline-level boxes with non-flow inner display establish new formatting context
399 // +spec:inline-formatting-context:1ad004 - atomic inline (inline-block) establishes new formatting context
400 // CSS 2.2 § 9.4.1: "inline-blocks... establish new block formatting contexts"
401 // +spec:inline-block:8d21f6 - inline-block generates inline-level block container (BFC inside, atomic inline outside)
402 // InlineBlock ALWAYS establishes a BFC for its contents.
403 // The element itself participates as an atomic inline in its parent's IFC,
404 // but its children are laid out in a BFC, not an IFC.
405 let mut temp_float_cache = HashMap::new();
406 layout_bfc(ctx, tree, text_cache, node_index, constraints, &mut temp_float_cache)
407 }
408 // +spec:table-layout:753687 - CSS 2.2 §17.2 table model: display values map to FormattingContext variants and dispatch table layout
409 FormattingContext::Table => layout_table_fc(ctx, tree, text_cache, node_index, constraints)
410 .map(BfcLayoutResult::from_output),
411 // Table-internal flex items are blockified during tree construction
412 // (blockify_flex_item_if_table_internal in layout_tree.rs), so they arrive
413 // here as Block, not TableCell etc.
414 FormattingContext::Flex | FormattingContext::Grid => {
415 layout_flex_grid(ctx, tree, text_cache, node_index, constraints)
416 }
417 // that are not block boxes, so they establish new BFCs for their contents
418 FormattingContext::TableCell | FormattingContext::TableCaption => {
419 let mut temp_float_cache = HashMap::new();
420 layout_bfc(ctx, tree, text_cache, node_index, constraints, &mut temp_float_cache)
421 }
422 _ => {
423 // Unknown formatting context - fall back to BFC
424 let mut temp_float_cache = HashMap::new();
425 layout_bfc(
426 ctx,
427 tree,
428 text_cache,
429 node_index,
430 constraints,
431 &mut temp_float_cache,
432 )
433 }
434 }
435}
436
437// Flex / grid layout (taffy Bridge)
438// containing block determined by grid-placement properties; Taffy handles this internally
439// (grid auto-placement §8.5 and abspos grid items use grid-area CB, not just padding box)
440
441/// Lays out a Flex or Grid formatting context using the Taffy layout engine.
442///
443/// # CSS Spec References
444///
445/// - CSS Flexbox § 9: Flex Layout Algorithm
446/// - CSS Grid § 12: Grid Layout Algorithm
447// gutters on either side of collapsed tracks collapse including distributed alignment space,
448// minimum contribution = outer size from min-width/min-height if specified size is auto else
449// min-content contribution) — all handled by Taffy grid implementation
450///
451/// # Implementation Notes
452///
453/// - Resolves explicit CSS dimensions to pixel values for `known_dimensions`
454/// - Uses `InherentSize` mode when explicit dimensions are set
455/// - Uses `ContentSize` mode for auto-sizing (shrink-to-fit)
456fn layout_flex_grid<T: ParsedFontTrait>(
457 ctx: &mut LayoutContext<'_, T>,
458 tree: &mut LayoutTree,
459 text_cache: &mut crate::font_traits::TextLayoutCache,
460 node_index: usize,
461 constraints: &LayoutConstraints,
462) -> Result<BfcLayoutResult> {
463 // Available space comes directly from constraints - margins are handled by Taffy
464 let available_space = TaffySize {
465 width: AvailableSpace::Definite(constraints.available_size.width),
466 height: AvailableSpace::Definite(constraints.available_size.height),
467 };
468
469 let node = tree.get(node_index).ok_or(LayoutError::InvalidTree)?;
470
471 // from flex line's cross size (clamped by min/max) when align-self:stretch, cross-size:auto,
472 // and neither cross-axis margin is auto. Otherwise uses hypothetical cross size.
473 // NOTE: visibility:collapse strut size for flex items is handled internally by Taffy.
474 //
475 // Resolve explicit CSS dimensions to pixel values.
476 // This is CRITICAL for align-items: stretch to work correctly!
477 // Taffy uses known_dimensions to calculate cross_axis_available_space for children.
478 let (explicit_width, has_explicit_width) =
479 resolve_explicit_dimension_width(ctx, node, constraints);
480 let (explicit_height, has_explicit_height) =
481 resolve_explicit_dimension_height(ctx, node, constraints);
482
483 // FIX: For root nodes or nodes where the parent provides a definite size,
484 // use the available_size as known_dimensions if no explicit CSS width/height is set.
485 // This is critical for `align-self: stretch` to work - Taffy needs to know the
486 // cross-axis size of the container to stretch children to fill it.
487 let is_root = node.parent.is_none();
488
489 let bp = node.box_props.unpack();
490 let width_adjustment = bp.border.left
491 + bp.border.right
492 + bp.padding.left
493 + bp.padding.right;
494 let height_adjustment = bp.border.top
495 + bp.border.bottom
496 + bp.padding.top
497 + bp.padding.bottom;
498
499 // `constraints.available_size` is the root's CONTENT-BOX (produced by
500 // `prepare_layout_context::inner_size(final_used_size)`), not the viewport
501 // border-box. Previously, the code used it as if it were border-box,
502 // causing taffy to subtract padding a second time and shrink the content
503 // area by 2x padding. For the root, pull the actual border-box from
504 // `node.used_size` (set by `calculate_used_size_for_node` before this call).
505 let root_border_box = node.used_size;
506
507 let effective_width = if has_explicit_width {
508 explicit_width
509 } else if is_root {
510 root_border_box.as_ref().map(|s| s.width).or_else(|| {
511 if constraints.available_size.width.is_finite() {
512 // Fallback: convert content-box to border-box.
513 Some(constraints.available_size.width + width_adjustment)
514 } else {
515 None
516 }
517 })
518 } else {
519 None
520 };
521 let effective_height = if has_explicit_height {
522 explicit_height
523 } else if is_root {
524 root_border_box.as_ref().map(|s| s.height).or_else(|| {
525 if constraints.available_size.height.is_finite() {
526 Some(constraints.available_size.height + height_adjustment)
527 } else {
528 None
529 }
530 })
531 } else {
532 None
533 };
534 let has_effective_width = effective_width.is_some();
535 let has_effective_height = effective_height.is_some();
536
537 // Taffy interprets known_dimensions as border-box. CSS width/height default
538 // to content-box, so explicit values need +padding+border added. For the
539 // ROOT element, however, we auto-apply box-sizing: border-box — the common
540 // CSS reset pattern — so `height:100%` + padding fits the viewport instead
541 // of overflowing by padding (which the default content-box interpretation
542 // would produce, since 100% of ICB is viewport-sized content, with padding
543 // added outside pushing border-box past the viewport).
544 let adjusted_width = if has_explicit_width && !is_root {
545 explicit_width.map(|w| w + width_adjustment)
546 } else if has_explicit_width && is_root {
547 explicit_width
548 } else {
549 effective_width
550 };
551 let adjusted_height = if has_explicit_height && !is_root {
552 explicit_height.map(|h| h + height_adjustment)
553 } else if has_explicit_height && is_root {
554 explicit_height
555 } else {
556 effective_height
557 };
558
559 // CSS Flexbox § 9.2: Use InherentSize when explicit dimensions are set,
560 // ContentSize for auto-sizing (shrink-to-fit behavior).
561 let sizing_mode = if has_effective_width || has_effective_height {
562 taffy::SizingMode::InherentSize
563 } else {
564 taffy::SizingMode::ContentSize
565 };
566
567 let known_dimensions = TaffySize {
568 width: adjusted_width,
569 height: adjusted_height,
570 };
571
572 // parent_size tells Taffy the size of the container's parent.
573 // For root nodes, the "parent" is the viewport, but since margins are already
574 // handled by calculate_used_size_for_node(), we use containing_block_size directly.
575 // For non-root nodes, containing_block_size is already the parent's content-box.
576 let parent_size = translate_taffy_size(constraints.containing_block_size);
577
578 let taffy_inputs = LayoutInput {
579 known_dimensions,
580 parent_size,
581 available_space,
582 run_mode: taffy::RunMode::PerformLayout,
583 sizing_mode,
584 axis: taffy::RequestedAxis::Both,
585 // Flex and Grid containers establish a new BFC, preventing margin collapse.
586 vertical_margins_are_collapsible: Line::FALSE,
587 };
588
589 debug_info!(
590 ctx,
591 "CALLING LAYOUT_TAFFY FOR FLEX/GRID FC node_index={:?}",
592 node_index
593 );
594
595 // For the root with auto-applied border-box: sync node.used_size so
596 // display-list rendering matches the border-box we handed taffy.
597 // Without this, the root's background/border would paint at the
598 // inflated size from calculate_used_size_for_node while taffy placed
599 // children inside a smaller content-box.
600 if is_root {
601 if let (Some(aw), Some(ah)) = (adjusted_width, adjusted_height) {
602 if let Some(node_mut) = tree.get_mut(node_index) {
603 node_mut.used_size = Some(LogicalSize::new(aw, ah));
604 }
605 }
606 }
607
608 // Cache border values before the mutable borrow in layout_taffy_subtree
609 let border_left = bp.border.left;
610 let border_top = bp.border.top;
611
612 let taffy_output =
613 taffy_bridge::layout_taffy_subtree(ctx, tree, text_cache, node_index, taffy_inputs);
614
615 // Collect child positions from the tree (Taffy stores results directly on nodes).
616 let mut output = LayoutOutput::default();
617 // Use content_size for overflow detection, not container size.
618 // content_size represents the actual size of all children, which may exceed the container.
619 //
620 // Taffy's content_size is measured from (0,0) of the border-box, so it includes
621 // border.top/left as a leading offset. The scrollbar geometry and scroll clamp
622 // both measure inside the padding-box (border stripped). Subtract the start
623 // border so that overflow_size is in the same coordinate space as the viewport
624 // (padding-box), preventing extra scroll range equal to the border width.
625 let raw = translate_taffy_size_back(taffy_output.content_size);
626 output.overflow_size = LogicalSize::new(
627 (raw.width - border_left).max(0.0),
628 (raw.height - border_top).max(0.0),
629 );
630
631 let children: Vec<usize> = tree.children(node_index).to_vec();
632 for &child_idx in &children {
633 if let Some(warm_node) = tree.warm(child_idx) {
634 if let Some(pos) = warm_node.relative_position {
635 output.positions.insert(child_idx, pos);
636 }
637 }
638 }
639
640 Ok(BfcLayoutResult::from_output(output))
641}
642
643/// Resolves explicit CSS width to pixel value for Taffy layout.
644fn resolve_explicit_dimension_width<T: ParsedFontTrait>(
645 ctx: &LayoutContext<'_, T>,
646 node: &LayoutNodeHot,
647 constraints: &LayoutConstraints,
648) -> (Option<f32>, bool) {
649 node.dom_node_id
650 .map(|id| {
651 let width = get_css_width(
652 ctx.styled_dom,
653 id,
654 &ctx.styled_dom.styled_nodes.as_container()[id].styled_node_state,
655 );
656 match width.unwrap_or_default() {
657 LayoutWidth::Auto => (None, false),
658 LayoutWidth::Px(px) => {
659 let pixels = resolve_size_metric(
660 px.metric,
661 px.number.get(),
662 constraints.available_size.width,
663 ctx.viewport_size,
664 );
665 (Some(pixels), true)
666 }
667 LayoutWidth::MinContent | LayoutWidth::MaxContent | LayoutWidth::FitContent(_) => (None, false),
668 LayoutWidth::Calc(items) => {
669 let node_state = &ctx.styled_dom.styled_nodes.as_container()[id].styled_node_state;
670 let em = get_element_font_size(ctx.styled_dom, id, node_state);
671 let calc_ctx = super::calc::CalcResolveContext {
672 items, em_size: em, rem_size: DEFAULT_FONT_SIZE,
673 };
674 let px = super::calc::evaluate_calc(&calc_ctx, constraints.available_size.width);
675 (Some(px), true)
676 }
677 }
678 })
679 .unwrap_or((None, false))
680}
681
682/// Resolves explicit CSS height to pixel value for Taffy layout.
683fn resolve_explicit_dimension_height<T: ParsedFontTrait>(
684 ctx: &LayoutContext<'_, T>,
685 node: &LayoutNodeHot,
686 constraints: &LayoutConstraints,
687) -> (Option<f32>, bool) {
688 node.dom_node_id
689 .map(|id| {
690 let height = get_css_height(
691 ctx.styled_dom,
692 id,
693 &ctx.styled_dom.styled_nodes.as_container()[id].styled_node_state,
694 );
695 match height.unwrap_or_default() {
696 LayoutHeight::Auto => (None, false),
697 LayoutHeight::Px(px) => {
698 let pixels = resolve_size_metric(
699 px.metric,
700 px.number.get(),
701 constraints.available_size.height,
702 ctx.viewport_size,
703 );
704 (Some(pixels), true)
705 }
706 LayoutHeight::MinContent | LayoutHeight::MaxContent | LayoutHeight::FitContent(_) => (None, false),
707 LayoutHeight::Calc(items) => {
708 let node_state = &ctx.styled_dom.styled_nodes.as_container()[id].styled_node_state;
709 let em = get_element_font_size(ctx.styled_dom, id, node_state);
710 let calc_ctx = super::calc::CalcResolveContext {
711 items, em_size: em, rem_size: DEFAULT_FONT_SIZE,
712 };
713 let px = super::calc::evaluate_calc(&calc_ctx, constraints.available_size.height);
714 (Some(px), true)
715 }
716 }
717 })
718 .unwrap_or((None, false))
719}
720
721// +spec:floats:167a2c - Float positioning rules (CSS 2.2 § 9.5.1): left/right/none, precise placement constraints
722// +spec:floats:6a1769 - Float shortens line boxes, margins never collapse, stacking order
723// +spec:floats:15bfd9 - float:right positions element at line-right edge within BFC
724// +spec:floats:afc8e2 - Float positioning rules (CSS 2.2 § 9.5 rules 1-8): left/right edge containment, earlier-float stacking, outer-top constraints, and "move down" when insufficient space
725/// Position a float within a BFC, considering existing floats.
726/// Returns the LogicalRect (margin box) for the float.
727// +spec:box-model:db0f02 - Float positioning: line boxes shortened by floats, floats shift down if no space, BFC elements must not overlap float margin boxes
728// +spec:containing-block:136e45 - Float shifted left/right until outer edge touches containing block edge or another float
729// +spec:containing-block:3ebb4e - Content moves below floats when containing block too narrow
730// +spec:floats:45fce7 - Float positioning: pulled out of flow, line boxes shortened around float
731// +spec:floats:f6c218 - float pulled out of flow, line boxes shorten around it
732// +spec:height-calculation:86142a - CSS 2.2 §9.5 float positioning, clearance, and margin non-collapsing
733// +spec:width-calculation:761677 - float positioning: content flows around floats, line boxes shortened by float presence
734fn position_float(
735 float_ctx: &FloatingContext,
736 float_type: LayoutFloat,
737 size: LogicalSize,
738 margin: &EdgeSizes,
739 current_main_offset: f32,
740 bfc_cross_size: f32,
741 wm: LayoutWritingMode,
742) -> LogicalRect {
743 // Start at the current main-axis position (Y in horizontal-tb)
744 let mut main_start = current_main_offset;
745
746 // Calculate total size including margins
747 let total_main = size.main(wm) + margin.main_start(wm) + margin.main_end(wm);
748 let total_cross = size.cross(wm) + margin.cross_start(wm) + margin.cross_end(wm);
749
750 // +spec:floats:3d89d8 - shift float downward when not enough horizontal room
751 // Find a position where the float fits
752 let cross_start = loop {
753 let (avail_start, avail_end) = float_ctx.available_line_box_space(
754 main_start,
755 main_start + total_main,
756 bfc_cross_size,
757 wm,
758 );
759
760 let available_width = avail_end - avail_start;
761
762 if available_width >= total_cross {
763 // +spec:floats:449158 - left float positioned at line-left, content flows on right
764 // Found space that fits
765 if float_type == LayoutFloat::Left {
766 // +spec:writing-modes:84bcba - floats positioned at line-left / line-right
767 // Position at line-left (avail_start)
768 break avail_start + margin.cross_start(wm);
769 } else {
770 // Position at line-right (avail_end - size)
771 break avail_end - total_cross + margin.cross_start(wm);
772 }
773 }
774
775 // top is moved lower than earlier float's bottom (outer edge / margin box bottom)
776 // Not enough space at this Y, move down past the lowest overlapping float's margin box bottom
777 let next_main = float_ctx
778 .floats
779 .iter()
780 .filter(|f| {
781 let f_main_start = f.rect.origin.main(wm) - f.margin.main_start(wm);
782 let f_main_end = f_main_start + f.rect.size.main(wm)
783 + f.margin.main_start(wm) + f.margin.main_end(wm);
784 f_main_end > main_start && f_main_start < main_start + total_main
785 })
786 .map(|f| f.rect.origin.main(wm) + f.rect.size.main(wm) + f.margin.main_end(wm))
787 .max_by(|a, b| a.partial_cmp(b).unwrap_or(std::cmp::Ordering::Equal));
788
789 if let Some(next) = next_main {
790 main_start = next;
791 } else {
792 // No overlapping floats found, use current position anyway
793 if float_type == LayoutFloat::Left {
794 break avail_start + margin.cross_start(wm);
795 } else {
796 break avail_end - total_cross + margin.cross_start(wm);
797 }
798 }
799 };
800
801 LogicalRect {
802 origin: LogicalPosition::from_main_cross(
803 main_start + margin.main_start(wm),
804 cross_start,
805 wm,
806 ),
807 size,
808 }
809}
810
811// Block Formatting Context (CSS 2.2 § 9.4.1)
812
813/// Lays out a Block Formatting Context (BFC).
814///
815/// This is the corrected, architecturally-sound implementation. It solves the
816/// "chicken-and-egg" problem by performing its own two-pass layout:
817///
818/// 1. **Sizing Pass:** It first iterates through its children and triggers their layout recursively
819/// by calling `calculate_layout_for_subtree`. This ensures that the `used_size` property of each
820/// child is correctly populated.
821///
822/// 2. **Positioning Pass:** It then iterates through the children again. Now that each child has a
823/// valid size, it can apply the standard block-flow logic: stacking them vertically and
824/// advancing a "pen" by each child's outer height.
825///
826/// # Margin Collapsing Architecture
827///
828/// CSS 2.1 Section 8.3.1 compliant margin collapsing:
829///
830/// ```text
831/// layout_bfc()
832/// ├─ Check parent border/padding blockers
833/// ├─ For each child:
834/// │ ├─ Check child border/padding blockers
835/// │ ├─ is_first_child?
836/// │ │ └─ Check parent-child top collapse
837/// │ ├─ Sibling collapse?
838/// │ │ └─ advance_pen_with_margin_collapse()
839/// │ │ └─ collapse_margins(prev_bottom, curr_top)
840/// │ ├─ Position child
841/// │ ├─ is_empty_block()?
842/// │ │ └─ Collapse own top+bottom margins (collapse through)
843/// │ └─ Save bottom margin for next sibling
844/// └─ Check parent-child bottom collapse
845/// ```
846///
847/// **Collapsing Rules:**
848///
849/// - Sibling margins: Adjacent vertical margins collapse to max (or sum if mixed signs)
850/// - Parent-child: First child's top margin can escape parent (if no border/padding)
851/// - Parent-child: Last child's bottom margin can escape parent (if no border/padding/height)
852/// - Empty blocks: Top+bottom margins collapse with each other, then with siblings
853/// - Blockers: Border, padding, inline content, or new BFC prevents collapsing
854///
855/// This approach is compliant with the CSS visual formatting model and works within
856/// the constraints of the existing layout engine architecture.
857// +spec:display-property:f38f52 - BFC handles normal flow, relative positioning offsets, and float extraction (CSS 2.2 § 9.8)
858fn layout_bfc<T: ParsedFontTrait>(
859 ctx: &mut LayoutContext<'_, T>,
860 tree: &mut LayoutTree,
861 text_cache: &mut crate::font_traits::TextLayoutCache,
862 node_index: usize,
863 constraints: &LayoutConstraints,
864 float_cache: &mut HashMap<usize, FloatingContext>,
865) -> Result<BfcLayoutResult> {
866 let node = tree
867 .get(node_index)
868 .ok_or(LayoutError::InvalidTree)?
869 .clone();
870 // +spec:block-formatting-context:4f4ff6 - writing-mode determines block flow direction (main axis) for ordering block-level boxes in BFC
871 let writing_mode = constraints.writing_mode;
872 let mut output = LayoutOutput::default();
873
874 debug_info!(
875 ctx,
876 "\n[layout_bfc] ENTERED for node_index={}, children.len()={}, incoming_bfc_state={}",
877 node_index,
878 tree.children(node_index).len(),
879 constraints.bfc_state.is_some()
880 );
881
882 // Initialize FloatingContext for this BFC
883 //
884 // We always recalculate float positions in this pass, but we'll store them in the cache
885 // so that subsequent layout passes (for auto-sizing) have access to the positioned floats
886 let mut float_context = FloatingContext::default();
887
888 // +spec:containing-block:42b75f - Block element establishes containing block for inline content (IFC)
889 // Calculate this node's content-box size for use as containing block for children
890 // CSS 2.2 § 10.1: The containing block for in-flow children is formed by the
891 // content edge of the parent's content box.
892 //
893 // We use constraints.available_size directly as this already represents the
894 // content-box available to this node (set by parent). For nodes with explicit
895 // sizes, used_size contains the border-box which we convert to content-box.
896 //
897 // NOTE(writing-modes): The containing block size uses physical width/height.
898 // In vertical writing modes, the block progression direction is horizontal,
899 // so the "available width" for children maps to the physical height of
900 // the containing block. The main_pen variable below tracks block progression
901 // using logical main-axis coordinates; the WritingModeContext in constraints
902 // determines how main/cross map to physical x/y via from_main_cross().
903 // +spec:inline-block:17944a - orthogonal flow roots get infinite available inline space here (not yet detected)
904 // +spec:inline-block:a60e22 - other layout models pass through infinite inline space to contained block containers
905 let mut children_containing_block_size = if let Some(used_size) = node.used_size {
906 // Node has used_size (border-box) - convert to content-box.
907 // For auto-height containers, the pre-layout `used_size.height` is a
908 // placeholder (calculate_used_size_for_node returns 0 for block-level
909 // auto-height; apply_content_based_height resolves it after children lay out).
910 // In that window, `constraints.available_size.height` holds the containing
911 // block's height — the value children should use as their own containing
912 // block for percentage-height resolution and indefinite-height semantics.
913 let inner = node.box_props.inner_size(used_size, writing_mode);
914 let height_is_auto = tree
915 .warm(node_index)
916 .map(|w| w.computed_style.height.is_none())
917 .unwrap_or(true);
918 if height_is_auto {
919 LogicalSize::new(inner.width, constraints.available_size.height)
920 } else {
921 inner
922 }
923 } else {
924 // No used_size yet - use available_size directly (this is already content-box
925 // when coming from parent's layout constraints)
926 constraints.available_size
927 };
928
929 // +spec:overflow:ffe6f7 - scrollbar space subtracted from containing block per spec §11.1.1
930 // Reserve space for vertical scrollbar when appropriate.
931 //
932 // - overflow: scroll → ALWAYS reserve (CSS spec: scrollbar always shown)
933 // - overflow: auto → Reserve ONLY when a previous pass / the anti-jitter
934 // merge (`merge_scrollbar_info`) already determined a scrollbar is needed.
935 // On the very first pass the node has no scrollbar_info yet, so no space
936 // is reserved. After `compute_scrollbar_info` detects overflow it sets
937 // `reflow_needed_for_scrollbars = true`, triggering a second pass where
938 // `node.scrollbar_info.needs_vertical == true` and space IS reserved.
939 // The merge uses `||` (keep once detected), preventing cross-frame jitter.
940 let scrollbar_reservation = node
941 .dom_node_id
942 .map(|dom_id| {
943 let styled_node_state = ctx
944 .styled_dom
945 .styled_nodes
946 .as_container()
947 .get(dom_id)
948 .map(|s| s.styled_node_state.clone())
949 .unwrap_or_default();
950 let overflow_y =
951 crate::solver3::getters::get_overflow_y(ctx.styled_dom, dom_id, &styled_node_state);
952 use azul_css::props::layout::LayoutOverflow;
953 match overflow_y.unwrap_or_default() {
954 LayoutOverflow::Scroll => {
955 crate::solver3::getters::get_layout_scrollbar_width_px(ctx, dom_id, &styled_node_state)
956 }
957 LayoutOverflow::Auto => {
958 let already_needs = tree.warm(node_index)
959 .and_then(|w| w.scrollbar_info.as_ref())
960 .map(|s| s.needs_vertical)
961 .unwrap_or(false);
962 if already_needs {
963 crate::solver3::getters::get_layout_scrollbar_width_px(ctx, dom_id, &styled_node_state)
964 } else {
965 0.0
966 }
967 }
968 _ => 0.0,
969 }
970 })
971 .unwrap_or(0.0);
972
973 if scrollbar_reservation > 0.0 {
974 children_containing_block_size.width =
975 (children_containing_block_size.width - scrollbar_reservation).max(0.0);
976 }
977
978 // === Pass 1: Pre-compute child sizes (restored two-pass BFC) ===
979 //
980 // Inspired by Taffy's two-pass approach: first measure, then position.
981 //
982 // This was removed in commit 1a3e5850 and replaced with a single-pass approach
983 // that computed sizes just-in-time during positioning. The single-pass approach
984 // caused regression 8e092a2e because positioning decisions (margin collapsing,
985 // float clearance, available width after floats) depend on knowing ALL sibling
986 // sizes upfront, not just the ones visited so far.
987 //
988 // With the per-node cache (§9.1-§9.2), the re-added Pass 1 is efficient:
989 // - Each child subtree is computed once and stored in NodeCache
990 // - Pass 2 positioning reads sizes from tree nodes (used_size set by Pass 1)
991 // - When calculate_layout_for_subtree recurses into children after layout_bfc
992 // returns, it hits the per-node cache (same available_size) — O(1) per child.
993 //
994 // Performance: O(n) for the tree. No double-computation thanks to caching.
995 {
996 let mut temp_positions: super::PositionVec = Vec::new();
997 let mut temp_scrollbar_reflow = false;
998
999 let bfc_children = tree.children(node_index).to_vec();
1000 for &child_index in &bfc_children {
1001 let child_node = tree.get(child_index).ok_or(LayoutError::InvalidTree)?;
1002 let child_dom_id = child_node.dom_node_id;
1003
1004 // +spec:positioning:447b06 - Absolute positioning pulls element out of flow, skip from normal layout
1005 // +spec:positioning:77a2d2 - Absolutely positioned children are ignored for auto height
1006 // +spec:positioning:b47ac2 - Only normal flow children taken into account for auto height
1007 // Skip absolutely/fixed positioned children — they're laid out separately
1008 // +spec:positioning:c7e5c5 - out-of-flow elements ignored for word boundary / hyphenation
1009 // +spec:positioning:7dd6d1 - Absolutely positioned boxes are taken out of the normal flow (no impact on later siblings, no margin collapsing)
1010 let position_type = get_position_type(ctx.styled_dom, child_dom_id);
1011 if position_type == LayoutPosition::Absolute || position_type == LayoutPosition::Fixed {
1012 continue;
1013 }
1014
1015 // Compute the child's full subtree layout with temporary positions.
1016 // Position (0,0) is intentionally wrong — Pass 1 only cares about sizing.
1017 // The correct positions are determined in Pass 2 below.
1018 crate::solver3::cache::calculate_layout_for_subtree(
1019 ctx,
1020 tree,
1021 text_cache,
1022 child_index,
1023 LogicalPosition::zero(),
1024 children_containing_block_size,
1025 &mut temp_positions,
1026 &mut temp_scrollbar_reflow,
1027 float_cache,
1028 crate::solver3::cache::ComputeMode::ComputeSize,
1029 )?;
1030 }
1031 }
1032
1033 // +spec:block-formatting-context:98b633 - CSS 2.2 § 9.4.1: boxes laid out vertically, margins collapse
1034 // === Pass 2: Position children using known sizes ===
1035 //
1036 // All children now have used_size set from Pass 1. This pass handles:
1037 // - Margin collapsing (parent-child + sibling-sibling)
1038 // - Float positioning and clearance
1039 // - Normal flow block positioning
1040
1041 let mut main_pen = 0.0f32;
1042 let mut max_cross_size = 0.0f32;
1043
1044 // Track escaped margins separately from content-box height
1045 // CSS 2.2 § 8.3.1: Escaped margins don't contribute to parent's content-box height,
1046 // but DO affect sibling positioning within the parent
1047 let mut total_escaped_top_margin = 0.0f32;
1048 // Track all inter-sibling margins (collapsed) - these are also not part of content height
1049 let mut total_sibling_margins = 0.0f32;
1050
1051 // Margin collapsing state
1052 let mut last_margin_bottom = 0.0f32;
1053 let mut is_first_child = true;
1054 let mut first_child_index: Option<usize> = None;
1055 let mut last_child_index: Option<usize> = None;
1056
1057 // Parent's own margins (for escape calculation)
1058 let node_bp = node.box_props.unpack();
1059 let parent_margin_top = node_bp.margin.main_start(writing_mode);
1060 let parent_margin_bottom = node_bp.margin.main_end(writing_mode);
1061
1062 // margins do not collapse across formatting context boundaries: an independent
1063 // BFC (float, overflow != visible, display: flex/grid, etc.) isolates its
1064 // children's margins. The DOM root is NOT a BFC boundary for this purpose —
1065 // its first child's margin still collapses through it (then gets absorbed at
1066 // the root, since there's no grandparent to escape to).
1067 let establishes_own_bfc = establishes_new_bfc(ctx, &node, tree.cold(node_index));
1068 let is_bfc_root = node.parent.is_none() || establishes_own_bfc;
1069
1070 // parent_has_*_blocker inhibits parent-child margin collapse per CSS 2.2 §8.3.1.
1071 // An explicit border/padding blocks, and an independent BFC blocks, but the
1072 // root on its own does not.
1073 let parent_has_top_blocker = establishes_own_bfc
1074 || has_margin_collapse_blocker(&node_bp, writing_mode, true);
1075 let parent_has_bottom_blocker = establishes_own_bfc
1076 || has_margin_collapse_blocker(&node_bp, writing_mode, false);
1077
1078 // Track accumulated top margin for first-child escape
1079 let mut accumulated_top_margin = 0.0f32;
1080 let mut top_margin_resolved = false;
1081 // Track if first child's margin escaped (for return value)
1082 let mut top_margin_escaped = false;
1083
1084 // Track if we have any actual content (non-empty blocks)
1085 let mut has_content = false;
1086
1087 // +spec:display-property:9f6e18 - BFC dispatches normal flow, floats, and relative positioning (CSS 2.2 §9.8)
1088 let pos_children = tree.children(node_index).to_vec();
1089 for &child_index in &pos_children {
1090 let child_node = tree.get(child_index).ok_or(LayoutError::InvalidTree)?;
1091 let child_dom_id = child_node.dom_node_id;
1092
1093 // +spec:floats:2cec1b - 'position' and 'float' determine the positioning algorithm
1094 // +spec:positioning:dccad6 - floats only apply to non-absolutely-positioned boxes
1095 let position_type = get_position_type(ctx.styled_dom, child_dom_id);
1096 if position_type == LayoutPosition::Absolute || position_type == LayoutPosition::Fixed {
1097 continue;
1098 }
1099
1100 // +spec:floats:2cec1b - float property determines positioning algorithm (float path)
1101 // +spec:floats:f6c0b2 - floats only processed in BFC; other formatting contexts (flex/grid) inhibit floating
1102 // Check if this child is a float - if so, position it at current main_pen
1103 let is_float = if let Some(node_id) = child_dom_id {
1104 let float_type = get_float_property(ctx.styled_dom, Some(node_id));
1105
1106 if float_type != LayoutFloat::None {
1107 // Calculate float size just-in-time if not already computed
1108 let float_size = match child_node.used_size {
1109 Some(size) => size,
1110 None => {
1111 let intrinsic = tree.warm(child_index).and_then(|w| w.intrinsic_sizes).unwrap_or_default();
1112 let child_bp = child_node.box_props.unpack();
1113 let computed_size = crate::solver3::sizing::calculate_used_size_for_node(
1114 ctx.styled_dom,
1115 child_dom_id,
1116 children_containing_block_size,
1117 intrinsic,
1118 &child_bp,
1119 ctx.viewport_size,
1120 )?;
1121 if let Some(node_mut) = tree.get_mut(child_index) {
1122 node_mut.used_size = Some(computed_size);
1123 }
1124 computed_size
1125 }
1126 };
1127 // Re-borrow after potential mutation
1128 let child_node = tree.get(child_index).ok_or(LayoutError::InvalidTree)?;
1129 let child_bp2 = child_node.box_props.unpack();
1130 let float_margin = &child_bp2.margin;
1131
1132 // +spec:floats:d0d163 - clear on floats adds constraint #10: float top below cleared floats' bottom
1133 // +spec:floats:7adb9d - Clear on floats: constraint #10, top outer edge must be below earlier cleared floats
1134 let float_clear = get_clear_property(ctx.styled_dom, Some(node_id));
1135 let float_y = if float_clear != LayoutClear::None {
1136 float_context.clearance_offset(float_clear, main_pen + last_margin_bottom, writing_mode)
1137 } else {
1138 // +spec:floats:ef96cb - Float margins never collapse with adjacent margins
1139 // CSS 2.2 § 9.5: Float margins don't collapse with any other margins.
1140 main_pen + last_margin_bottom
1141 };
1142
1143 debug_info!(
1144 ctx,
1145 "[layout_bfc] Positioning float: index={}, type={:?}, size={:?}, at Y={} \
1146 (main_pen={} + last_margin={})",
1147 child_index,
1148 float_type,
1149 float_size,
1150 float_y,
1151 main_pen,
1152 last_margin_bottom
1153 );
1154
1155 // Position the float at the CURRENT main_pen + last margin (respects DOM order!)
1156 let float_rect = position_float(
1157 &float_context,
1158 float_type,
1159 float_size,
1160 float_margin,
1161 // Include last_margin_bottom since float margins don't collapse!
1162 float_y,
1163 constraints.available_size.cross(writing_mode),
1164 writing_mode,
1165 );
1166
1167 debug_info!(ctx, "[layout_bfc] Float positioned at: {:?}", float_rect);
1168
1169 // Add to float context BEFORE positioning next element
1170 float_context.add_float(float_type, float_rect, *float_margin);
1171
1172 // Store position in output
1173 output.positions.insert(child_index, float_rect.origin);
1174
1175 debug_info!(
1176 ctx,
1177 "[layout_bfc] *** FLOAT POSITIONED: child={}, main_pen={} (unchanged - floats \
1178 don't advance pen)",
1179 child_index,
1180 main_pen
1181 );
1182
1183 // Floats are taken out of normal flow - DON'T advance main_pen
1184 // Continue to next child
1185 continue;
1186 }
1187 false
1188 } else {
1189 false
1190 };
1191
1192 // Early exit for floats (already handled above)
1193 if is_float {
1194 continue;
1195 }
1196
1197 // From here: normal flow (non-float) children only
1198
1199 // Track first and last in-flow children for parent-child collapse
1200 if first_child_index.is_none() {
1201 first_child_index = Some(child_index);
1202 }
1203 last_child_index = Some(child_index);
1204
1205 // Calculate child's used_size just-in-time if not already computed
1206 // This replaces the old "Pass 1" that recursively laid out grandchildren with wrong positions
1207 let child_size = match child_node.used_size {
1208 Some(size) => size,
1209 None => {
1210 // Calculate size without recursive layout
1211 let intrinsic = tree.warm(child_index).and_then(|w| w.intrinsic_sizes).unwrap_or_default();
1212 let child_used_size = crate::solver3::sizing::calculate_used_size_for_node(
1213 ctx.styled_dom,
1214 child_dom_id,
1215 children_containing_block_size,
1216 intrinsic,
1217 &child_node.box_props.unpack(),
1218 ctx.viewport_size,
1219 )?;
1220 // Update the node with computed size (we need to re-borrow mutably)
1221 if let Some(node_mut) = tree.get_mut(child_index) {
1222 node_mut.used_size = Some(child_used_size);
1223 }
1224 child_used_size
1225 }
1226 };
1227 // Re-borrow child_node after potential mutation
1228 let child_node = tree.get(child_index).ok_or(LayoutError::InvalidTree)?;
1229 let child_bp = child_node.box_props.unpack();
1230 let child_margin = &child_bp.margin;
1231
1232 debug_info!(
1233 ctx,
1234 "[layout_bfc] Child {} margin from box_props: top={}, right={}, bottom={}, left={}",
1235 child_index,
1236 child_margin.top,
1237 child_margin.right,
1238 child_margin.bottom,
1239 child_margin.left
1240 );
1241
1242 // +spec:block-formatting-context:0f802c - margins use containing block's writing mode for collapsing/auto expansion in orthogonal flows
1243 let child_own_margin_top = child_margin.main_start(writing_mode);
1244 let child_own_margin_bottom = child_margin.main_end(writing_mode);
1245
1246 // CSS 2.2 § 8.3.1: If a child has no top blocker (no padding/border) and its
1247 // own BFC layout produced an escaped_top_margin, that margin represents the
1248 // collapsed value of (child's margin, child's first child's margin, ...).
1249 // Use it for sibling collapse instead of the child's own margin.
1250 let child_escaped_top = if !has_margin_collapse_blocker(&child_bp, writing_mode, true) {
1251 tree.warm(child_index).and_then(|w| w.escaped_top_margin)
1252 } else { None };
1253 let child_escaped_bottom = if !has_margin_collapse_blocker(&child_bp, writing_mode, false) {
1254 tree.warm(child_index).and_then(|w| w.escaped_bottom_margin)
1255 } else { None };
1256
1257 let child_margin_top = child_escaped_top.unwrap_or(child_own_margin_top);
1258 let child_margin_bottom = child_escaped_bottom.unwrap_or(child_own_margin_bottom);
1259
1260 debug_info!(
1261 ctx,
1262 "[layout_bfc] Child {} final margins: margin_top={}, margin_bottom={}",
1263 child_index,
1264 child_margin_top,
1265 child_margin_bottom
1266 );
1267
1268 // Check if this child has border/padding that prevents margin collapsing
1269 let child_has_top_blocker =
1270 has_margin_collapse_blocker(&child_bp, writing_mode, true);
1271 let child_has_bottom_blocker =
1272 has_margin_collapse_blocker(&child_bp, writing_mode, false);
1273
1274 // +spec:floats:dc195a - Clear property only applies to block-level elements (CSS 2.2 § 9.5.2)
1275 // Check for clear property FIRST - clearance affects whether element is considered empty
1276 // CSS 2.2 § 9.5.2: "Clearance inhibits margin collapsing"
1277 // An element with clearance is NOT empty even if it has no content
1278 let child_clear = if let Some(node_id) = child_dom_id {
1279 get_clear_property(ctx.styled_dom, Some(node_id))
1280 } else {
1281 LayoutClear::None
1282 };
1283 debug_info!(
1284 ctx,
1285 "[layout_bfc] Child {} clear property: {:?}",
1286 child_index,
1287 child_clear
1288 );
1289
1290 // PHASE 1: Empty Block Detection & Self-Collapse
1291 let is_empty = is_empty_block(tree, child_index);
1292
1293 // Handle empty blocks FIRST (they collapse through and don't participate in layout)
1294 // EXCEPTION: Elements with clear property are NOT skipped even if empty!
1295 // CSS 2.2 § 9.5.2: Clear property affects positioning even for empty elements
1296 if is_empty
1297 && !child_has_top_blocker
1298 && !child_has_bottom_blocker
1299 && child_clear == LayoutClear::None
1300 {
1301 // Empty block: collapse its own top and bottom margins FIRST
1302 let self_collapsed = collapse_margins(child_margin_top, child_margin_bottom);
1303
1304 // Then collapse with previous margin (sibling or parent)
1305 if is_first_child {
1306 is_first_child = false;
1307 // Empty first child: its collapsed margin can escape with parent's
1308 if !parent_has_top_blocker {
1309 accumulated_top_margin = collapse_margins(parent_margin_top, self_collapsed);
1310 } else {
1311 // Parent has blocker: add margins
1312 if accumulated_top_margin == 0.0 {
1313 accumulated_top_margin = parent_margin_top;
1314 }
1315 main_pen += accumulated_top_margin + self_collapsed;
1316 top_margin_resolved = true;
1317 accumulated_top_margin = 0.0;
1318 }
1319 last_margin_bottom = self_collapsed;
1320 } else {
1321 // Empty sibling: collapse with previous sibling's bottom margin
1322 last_margin_bottom = collapse_margins(last_margin_bottom, self_collapsed);
1323 }
1324
1325 // Skip positioning and pen advance (empty has no visual presence)
1326 continue;
1327 }
1328
1329 // From here on: non-empty blocks only (or empty blocks with clear property)
1330
1331 // Apply clearance if needed
1332 // +spec:floats:148ee6 - clear:left pushes element below float; clearance added above top margin
1333 // CSS 2.2 § 9.5.2: Clearance inhibits margin collapsing.
1334 //
1335 // Per CSS 2.2 § 9.5.2, the clearance computation works as follows:
1336 // 1. Compute the "hypothetical position" — where the border edge would be
1337 // with normal margin collapsing (as if clear:none).
1338 // 2. If the hypothetical position is NOT past the relevant floats,
1339 // clearance is introduced and the border edge is placed at float bottom.
1340 // 3. The final border edge = max(float_bottom, hypothetical_position).
1341 //
1342 // This means child_margin_top is already accounted for in the hypothetical
1343 // position and must NOT be added again after clearance positions main_pen.
1344 let clearance_applied = if child_clear != LayoutClear::None {
1345 let hypothetical = main_pen + collapse_margins(last_margin_bottom, child_margin_top);
1346 let cleared_position =
1347 float_context.clearance_offset(child_clear, hypothetical, writing_mode);
1348 debug_info!(
1349 ctx,
1350 "[layout_bfc] Child {} clearance check: cleared_position={}, hypothetical={} (main_pen={} + collapse({}, {}))",
1351 child_index,
1352 cleared_position,
1353 hypothetical,
1354 main_pen,
1355 last_margin_bottom,
1356 child_margin_top
1357 );
1358 if cleared_position > hypothetical {
1359 debug_info!(
1360 ctx,
1361 "[layout_bfc] Applying clearance: child={}, clear={:?}, old_pen={}, new_pen={}",
1362 child_index,
1363 child_clear,
1364 main_pen,
1365 cleared_position
1366 );
1367 main_pen = cleared_position;
1368 true // Signal that clearance was applied
1369 } else {
1370 false
1371 }
1372 } else {
1373 false
1374 };
1375
1376 // PHASE 2: Parent-Child Top Margin Escape (First Child)
1377 //
1378 // CSS 2.2 § 8.3.1: "The top margin of a box is adjacent to the top margin of its first
1379 // in-flow child if the box has no top border, no top padding, and the child has no
1380 // clearance." CSS 2.2 § 9.5.2: "Clearance inhibits margin collapsing"
1381
1382 if is_first_child {
1383 is_first_child = false;
1384
1385 // Clearance prevents collapse (acts as invisible blocker)
1386 if clearance_applied {
1387 // Clearance inhibits all margin collapsing for this element
1388 // The clearance has already positioned main_pen at the correct
1389 // border-edge position (= max(float_bottom, hypothetical)).
1390 // The hypothetical already includes child_margin_top via
1391 // collapse_margins, so we must NOT add it again here.
1392 debug_info!(
1393 ctx,
1394 "[layout_bfc] First child {} with CLEARANCE: no collapse, child_margin={}, \
1395 main_pen={}",
1396 child_index,
1397 child_margin_top,
1398 main_pen
1399 );
1400 } else if !parent_has_top_blocker {
1401 // Margin Escape Case
1402 //
1403 // CSS 2.2 § 8.3.1: "The top margin of an in-flow block element collapses with
1404 // its first in-flow block-level child's top margin if the element has no top
1405 // border, no top padding, and the child has no clearance."
1406 //
1407 // When margins collapse, they "escape" upward through the parent to be resolved
1408 // in the grandparent's coordinate space. This is critical for understanding the
1409 // coordinate system separation:
1410 //
1411 // Example:
1412 // <body padding=20>
1413 // <div margin=0>
1414 // <div margin=30></div>
1415 // </div>
1416 // </body>
1417 //
1418 // - Middle div (our parent) has no padding → margins can escape
1419 // - Inner div's 30px margin collapses with middle div's 0px margin = 30px
1420 // - This 30px margin "escapes" to be handled by body's BFC
1421 // - Body positions middle div at Y=30 (relative to body's content-box)
1422 // - Middle div's content-box height does NOT include the escaped 30px
1423 // - Inner div is positioned at Y=0 in middle div's content-box
1424 //
1425 // **NOTE**: This is a subtle but critical distinction in coordinate systems:
1426 //
1427 // - Parent's margin belongs to grandparent's coordinate space
1428 // - Child's margin (when escaped) also belongs to grandparent's coordinate space
1429 // - They collapse BEFORE entering this BFC's coordinate space
1430 // - We return the collapsed margin so grandparent can position parent correctly
1431 //
1432 // **NOTE**: Child's own blocker status (padding/border) is IRRELEVANT for
1433 // parent-child collapse. The child may have padding that prevents
1434 // collapse with ITS OWN children, but this doesn't prevent its
1435 // margin from escaping through its parent.
1436 //
1437 // **NOTE**: Previously, we incorrectly added parent_margin_top to main_pen in
1438 // the blocked case, which double-counted the margin by mixing
1439 // coordinate systems. The parent's margin is NEVER in our (the
1440 // parent's content-box) coordinate system!
1441 //
1442 // We collapse the parent's margin with the child's margin.
1443 // This combined margin is what "escapes" to the grandparent.
1444 // The grandparent uses this to position the parent.
1445 //
1446 // Effectively, we are saying "The parent starts here, but its effective
1447 // top margin is now max(parent_margin, child_margin)".
1448
1449 accumulated_top_margin = collapse_margins(parent_margin_top, child_margin_top);
1450 top_margin_resolved = true;
1451 top_margin_escaped = true;
1452
1453 // Track escaped margin so it gets subtracted from content-box height
1454 // The escaped margin is NOT part of our content-box - it belongs to our
1455 // parent's parent
1456 total_escaped_top_margin = accumulated_top_margin;
1457
1458 // Position child at pen (no margin applied - it escaped!)
1459 debug_info!(
1460 ctx,
1461 "[layout_bfc] First child {} margin ESCAPES: parent_margin={}, \
1462 child_margin={}, collapsed={}, total_escaped={}",
1463 child_index,
1464 parent_margin_top,
1465 child_margin_top,
1466 accumulated_top_margin,
1467 total_escaped_top_margin
1468 );
1469 } else {
1470 // Margin Blocked Case
1471 //
1472 // CSS 2.2 § 8.3.1: "no top padding and no top border" required for collapse.
1473 // When padding or border exists, margins do NOT collapse and exist in different
1474 // coordinate spaces.
1475 //
1476 // CRITICAL COORDINATE SYSTEM SEPARATION:
1477 //
1478 // This is where the architecture becomes subtle. When layout_bfc() is called:
1479 // 1. We are INSIDE the parent's content-box coordinate space (main_pen starts at
1480 // 0)
1481 // 2. The parent's own margin was ALREADY RESOLVED by the grandparent's BFC
1482 // 3. The parent's margin is in the grandparent's coordinate space, not ours
1483 // 4. We NEVER reference the parent's margin in this BFC - it's outside our scope
1484 //
1485 // Example:
1486 //
1487 // <body padding=20>
1488 // <div margin=30 padding=20>
1489 // <div margin=30></div>
1490 // </div>
1491 // </body>
1492 //
1493 // - Middle div has padding=20 → blocker exists, margins don't collapse
1494 // - Body's BFC positions middle div at Y=30 (middle div's margin, in body's
1495 // space)
1496 // - Middle div's BFC starts at its content-box (after the padding)
1497 // - main_pen=0 at the top of middle div's content-box
1498 // - Inner div has margin=30 → we add 30 to main_pen (in OUR coordinate space)
1499 // - Inner div positioned at Y=30 (relative to middle div's content-box)
1500 // - Absolute position: 20 (body padding) + 30 (middle margin) + 20 (middle
1501 // padding) + 30 (inner margin) = 100px
1502 //
1503 // **NOTE**: Previous code incorrectly added parent_margin_top to main_pen here:
1504 //
1505 // - main_pen += parent_margin_top; // WRONG! Mixes coordinate systems
1506 // - main_pen += child_margin_top;
1507 //
1508 // This caused the "double margin" bug where margins were applied twice:
1509 //
1510 // - Once by grandparent positioning parent (correct)
1511 // - Again inside parent's BFC (INCORRECT - wrong coordinate system)
1512 //
1513 // The parent's margin belongs to GRANDPARENT's coordinate space and was already
1514 // used to position the parent. Adding it again here is like adding feet to
1515 // meters.
1516 //
1517 // We ONLY add the child's margin in our (parent's content-box) coordinate space.
1518 // The parent's margin is irrelevant to us - it's outside our scope.
1519
1520 main_pen += child_margin_top;
1521 debug_info!(
1522 ctx,
1523 "[layout_bfc] First child {} BLOCKED: parent_has_blocker={}, advanced by \
1524 child_margin={}, main_pen={}",
1525 child_index,
1526 parent_has_top_blocker,
1527 child_margin_top,
1528 main_pen
1529 );
1530 }
1531 } else {
1532 // Not first child: handle sibling collapse
1533 // CSS 2.2 § 8.3.1 Rule 1: "Vertical margins of adjacent block boxes in the normal flow
1534 // collapse" CSS 2.2 § 9.5.2: "Clearance inhibits margin collapsing"
1535
1536 // Resolve accumulated top margin if not yet done (for parent's first in-flow child)
1537 if !top_margin_resolved {
1538 main_pen += accumulated_top_margin;
1539 top_margin_resolved = true;
1540 debug_info!(
1541 ctx,
1542 "[layout_bfc] RESOLVED top margin for node {} at sibling {}: accumulated={}, \
1543 main_pen={}",
1544 node_index,
1545 child_index,
1546 accumulated_top_margin,
1547 main_pen
1548 );
1549 }
1550
1551 if clearance_applied {
1552 // Clearance has already positioned main_pen at the correct
1553 // border-edge = max(float_bottom, hypothetical). The hypothetical
1554 // already includes collapse_margins(last_margin_bottom, child_margin_top),
1555 // so we must NOT add child_margin_top again here.
1556 debug_info!(
1557 ctx,
1558 "[layout_bfc] Child {} with CLEARANCE: no collapse with sibling, \
1559 child_margin_top={}, main_pen={}",
1560 child_index,
1561 child_margin_top,
1562 main_pen
1563 );
1564 } else {
1565 // Sibling Margin Collapse
1566 //
1567 // CSS 2.2 § 8.3.1: "Vertical margins of adjacent block boxes in the normal
1568 // flow collapse." The collapsed margin is the maximum of the two margins.
1569 //
1570 // IMPORTANT: Sibling margins ARE part of the parent's content-box height!
1571 //
1572 // Unlike escaped margins (which belong to grandparent's space), sibling margins
1573 // are the space BETWEEN children within our content-box.
1574 //
1575 // Example:
1576 //
1577 // <div>
1578 // <div margin-bottom=30></div>
1579 // <div margin-top=40></div>
1580 // </div>
1581 //
1582 // - First child ends at Y=100 (including its content + margins)
1583 // - Collapsed margin = max(30, 40) = 40px
1584 // - Second child starts at Y=140 (100 + 40)
1585 // - Parent's content-box height includes this 40px gap
1586 //
1587 // We track total_sibling_margins for debugging, but NOTE: we do **not**
1588 // subtract these from content-box height! They are part of the layout space.
1589 //
1590 // Previously we subtracted total_sibling_margins from content-box height:
1591 //
1592 // content_box_height = main_pen - total_escaped_top_margin -
1593 // total_sibling_margins;
1594 //
1595 // This was wrong because sibling margins are between boxes (part of content),
1596 // not outside boxes (like escaped margins).
1597
1598 let collapsed = collapse_margins(last_margin_bottom, child_margin_top);
1599 main_pen += collapsed;
1600 total_sibling_margins += collapsed;
1601 debug_info!(
1602 ctx,
1603 "[layout_bfc] Sibling collapse for child {}: last_margin_bottom={}, \
1604 child_margin_top={}, collapsed={}, main_pen={}, total_sibling_margins={}",
1605 child_index,
1606 last_margin_bottom,
1607 child_margin_top,
1608 collapsed,
1609 main_pen,
1610 total_sibling_margins
1611 );
1612 }
1613 }
1614
1615 // Position child (non-empty blocks only reach here)
1616 //
1617 // +spec:block-formatting-context:1dada5 - Normal flow boxes in BFC touch containing block edge
1618 // +spec:block-formatting-context:9f56cb - each box's left outer edge touches containing block left edge; new BFC may shrink due to floats
1619 // CSS 2.2 § 9.4.1: "In a block formatting context, each box's left outer edge touches
1620 // the left edge of the containing block (for right-to-left formatting, right edges touch).
1621 // This is true even in the presence of floats (although a box's line boxes may shrink
1622 // due to the floats), unless the box establishes a new block formatting context
1623 // (in which case the box itself may become narrower due to the floats)."
1624 //
1625 // +spec:block-formatting-context:3d2811 - Float overlap with normal flow element borders
1626 // +spec:display-property:796059 - BFC/replaced/table border box must not overlap float margin boxes; line boxes shorten around floats
1627 // +spec:floats:5214a6 - BFC/replaced/table border box must not overlap float margin boxes; shrink or clear below
1628 // CSS 2.2 § 9.5: "The border box of a table, a block-level replaced element, or an element
1629 // in the normal flow that establishes a new block formatting context (such as an element
1630 // with 'overflow' other than 'visible') must not overlap any floats in the same block
1631 // formatting context as the element itself."
1632
1633 // +spec:floats:a29f70 - BFC roots, tables, and block-level replaced elements must not overlap float margin boxes
1634 let child_node = tree.get(child_index).ok_or(LayoutError::InvalidTree)?;
1635 let avoids_floats = establishes_new_bfc(ctx, child_node, tree.cold(child_index))
1636 || is_block_level_replaced(ctx, child_node);
1637
1638 // Query available space considering floats ONLY if child avoids floats
1639 let (cross_start, cross_end, available_cross) = if avoids_floats {
1640 // New BFC / replaced / table: Must shrink or move down to avoid overlapping floats
1641 let child_cross_needed = child_size.cross(writing_mode);
1642 let bfc_cross = constraints.available_size.cross(writing_mode);
1643
1644 let (mut start, mut end) = float_context.available_line_box_space(
1645 main_pen,
1646 main_pen + child_size.main(writing_mode),
1647 bfc_cross,
1648 writing_mode,
1649 );
1650 let mut available = end - start;
1651
1652 // CSS 2.2 § 9.5: "If necessary, implementations should clear the said element
1653 // by placing it below any preceding floats, but may place it adjacent to such
1654 // floats if there is sufficient space."
1655 if available < child_cross_needed && !float_context.floats.is_empty() {
1656 let clear_to = float_context.floats.iter()
1657 .filter(|f| {
1658 let f_main_start = f.rect.origin.main(writing_mode) - f.margin.main_start(writing_mode);
1659 let f_main_end = f_main_start + f.rect.size.main(writing_mode)
1660 + f.margin.main_start(writing_mode) + f.margin.main_end(writing_mode);
1661 f_main_end > main_pen && f_main_start < main_pen + child_size.main(writing_mode)
1662 })
1663 .map(|f| {
1664 f.rect.origin.main(writing_mode) + f.rect.size.main(writing_mode)
1665 + f.margin.main_end(writing_mode)
1666 })
1667 .fold(main_pen, f32::max);
1668
1669 if clear_to > main_pen {
1670 main_pen = clear_to;
1671 let (s, e) = float_context.available_line_box_space(
1672 main_pen,
1673 main_pen + child_size.main(writing_mode),
1674 bfc_cross,
1675 writing_mode,
1676 );
1677 start = s;
1678 end = e;
1679 available = end - start;
1680 }
1681 }
1682
1683 debug_info!(
1684 ctx,
1685 "[layout_bfc] Child {} avoids floats: shrinking to avoid floats, \
1686 cross_range={}..{}, available_cross={}",
1687 child_index,
1688 start,
1689 end,
1690 available
1691 );
1692
1693 (start, end, available)
1694 } else {
1695 // Normal flow: Overlaps floats, positioned at full width
1696 // Only the child's INLINE CONTENT (if any) wraps around floats
1697 let start = 0.0;
1698 let end = constraints.available_size.cross(writing_mode);
1699 let available = end - start;
1700
1701 debug_info!(
1702 ctx,
1703 "[layout_bfc] Child {} is normal flow: overlapping floats at full width, \
1704 available_cross={}",
1705 child_index,
1706 available
1707 );
1708
1709 (start, end, available)
1710 };
1711
1712 // Get child's margin, margin_auto, size, and formatting context
1713 let (child_margin_cloned, child_margin_auto, child_used_size, is_inline_fc, child_dom_id_for_debug) = {
1714 let child_node = tree.get(child_index).ok_or(LayoutError::InvalidTree)?;
1715 let cbp = child_node.box_props.unpack();
1716 (
1717 cbp.margin.clone(),
1718 cbp.margin_auto,
1719 child_node.used_size.unwrap_or_default(),
1720 child_node.formatting_context == FormattingContext::Inline,
1721 child_node.dom_node_id,
1722 )
1723 };
1724 let child_margin = &child_margin_cloned;
1725
1726 debug_info!(
1727 ctx,
1728 "[layout_bfc] Child {} margin_auto: left={}, right={}, top={}, bottom={}",
1729 child_index,
1730 child_margin_auto.left,
1731 child_margin_auto.right,
1732 child_margin_auto.top,
1733 child_margin_auto.bottom
1734 );
1735 debug_info!(
1736 ctx,
1737 "[layout_bfc] Child {} used_size: width={}, height={}",
1738 child_index,
1739 child_used_size.width,
1740 child_used_size.height
1741 );
1742
1743 // Position child
1744 // For normal flow blocks (including IFCs): position at full width (cross_start = 0)
1745 // For BFC-establishing blocks: position in available space between floats
1746 //
1747 // CSS 2.2 § 10.3.3: If margin-left and margin-right are both auto,
1748 // their used values are equal, centering the element horizontally.
1749
1750 let (child_cross_pos, mut child_main_pos) = if avoids_floats {
1751 // BFC: Position in float-free space, but also check margin:auto centering.
1752 // A flex container or overflow:hidden box establishes a BFC (must avoid floats)
1753 // but can still be centered via margin:auto — these are independent concepts.
1754 let cross_pos = if child_margin_auto.left && child_margin_auto.right {
1755 let remaining = (available_cross - child_used_size.cross(writing_mode)).max(0.0);
1756 debug_info!(
1757 ctx,
1758 "[layout_bfc] Child {} BFC + margin:auto centering: available={}, size={}, offset={}",
1759 child_index, available_cross, child_used_size.cross(writing_mode), remaining / 2.0
1760 );
1761 cross_start + remaining / 2.0
1762 } else if child_margin_auto.left {
1763 let remaining = (available_cross - child_used_size.cross(writing_mode) - child_margin.right).max(0.0);
1764 cross_start + remaining
1765 } else {
1766 cross_start + child_margin.cross_start(writing_mode)
1767 };
1768 (cross_pos, main_pen)
1769 } else {
1770 // Normal flow: Check for margin: auto centering
1771 let available_cross = constraints.available_size.cross(writing_mode);
1772 let child_cross_size = child_used_size.cross(writing_mode);
1773
1774 debug_info!(
1775 ctx,
1776 "[layout_bfc] Child {} centering check: available_cross={}, child_cross_size={}, margin_auto.left={}, margin_auto.right={}",
1777 child_index,
1778 available_cross,
1779 child_cross_size,
1780 child_margin_auto.left,
1781 child_margin_auto.right
1782 );
1783
1784 // +spec:block-formatting-context:d52ce5 - auto margins resolved per containing block's writing mode for centering
1785 // +spec:width-calculation:0c5044 - auto margins center element on cross axis (respects writing mode)
1786 // +spec:width-calculation:25c2fc - §10.3.3: block-level margin auto centering and over-constrained resolution
1787 // +spec:width-calculation:ba691f - auto margins treated as zero when element overflows containing block (via .max(0.0) on remaining_space)
1788 // +spec:width-calculation:324e7e - both margin-left and margin-right auto => equal used values (centering)
1789 // CSS 2.2 § 10.3.3: If both margin-left and margin-right are auto,
1790 // center the element within the available space
1791 let cross_pos = if child_margin_auto.left && child_margin_auto.right {
1792 // Center: (available - child_width) / 2
1793 let remaining_space = (available_cross - child_cross_size).max(0.0);
1794 debug_info!(
1795 ctx,
1796 "[layout_bfc] Child {} CENTERING: remaining_space={}, cross_pos={}",
1797 child_index,
1798 remaining_space,
1799 remaining_space / 2.0
1800 );
1801 remaining_space / 2.0
1802 } else if child_margin_auto.left {
1803 // Only left is auto: push element to the right
1804 let remaining_space = (available_cross - child_cross_size - child_margin.right).max(0.0);
1805 debug_info!(
1806 ctx,
1807 "[layout_bfc] Child {} margin-left:auto only, pushing right: remaining_space={}",
1808 child_index,
1809 remaining_space
1810 );
1811 remaining_space
1812 } else if child_margin_auto.right {
1813 // Only right is auto: element stays at left with its margin
1814 debug_info!(
1815 ctx,
1816 "[layout_bfc] Child {} margin-right:auto only, using left margin={}",
1817 child_index,
1818 child_margin.cross_start(writing_mode)
1819 );
1820 child_margin.cross_start(writing_mode)
1821 } else {
1822 // +spec:box-model:218643 - over-constrained: drop end margin per containing block writing mode
1823 // +spec:width-calculation:d172a4 - over-constrained: LTR ignores margin-right, RTL ignores margin-left
1824 // in LTR, margin-right is ignored (element positioned at margin-left);
1825 // in RTL, margin-left is ignored (element positioned from right edge)
1826 let is_rtl = tree.get(node_index)
1827 .and_then(|n| n.dom_node_id)
1828 .map_or(false, |cb_dom_id| {
1829 let node_state = ctx.styled_dom.styled_nodes.as_container()
1830 .get(cb_dom_id)
1831 .map(|s| s.styled_node_state.clone())
1832 .unwrap_or_default();
1833 matches!(
1834 get_direction_property(ctx.styled_dom, cb_dom_id, &node_state),
1835 MultiValue::Exact(StyleDirection::Rtl)
1836 )
1837 });
1838 let cross_pos = if is_rtl {
1839 // RTL: ignore margin-left, position from right edge
1840 available_cross - child_cross_size - child_margin.cross_end(writing_mode)
1841 } else {
1842 // LTR (default): ignore margin-right, position at margin-left
1843 child_margin.cross_start(writing_mode)
1844 };
1845 debug_info!(
1846 ctx,
1847 "[layout_bfc] Child {} NO auto margins (over-constrained), is_rtl={}, cross_pos={}",
1848 child_index,
1849 is_rtl,
1850 cross_pos
1851 );
1852 cross_pos
1853 };
1854
1855 (cross_pos, main_pen)
1856 };
1857
1858 // NOTE: We do NOT adjust child_main_pos based on child's escaped_top_margin here!
1859 // The escaped_top_margin represents margins that escaped FROM the child's own children.
1860 // The child's position in THIS BFC is determined by main_pen and the child's own margin
1861 // (which was already handled in the margin collapse logic above).
1862 //
1863 // Previously, this code incorrectly added child_escaped_margin to child_main_pos,
1864 // which caused double-application of margins because:
1865 // 1. The child's margin was used to calculate its position in THIS BFC
1866 // 2. Then its escaped_top_margin (which included its own margin) was added again
1867 //
1868 // The correct behavior per CSS 2.2 § 8.3.1 is:
1869 // - The child's escaped_top_margin is used by THIS node's parent to position THIS node
1870 // - It does NOT affect how we position the child within our content-box
1871
1872 // final_pos is [CoordinateSpace::Parent] - relative to this BFC's content-box
1873 let final_pos =
1874 LogicalPosition::from_main_cross(child_main_pos, child_cross_pos, writing_mode);
1875
1876 debug_info!(
1877 ctx,
1878 "[layout_bfc] *** NORMAL FLOW BLOCK POSITIONED: child={}, final_pos={:?}, \
1879 main_pen={}, avoids_floats={}",
1880 child_index,
1881 final_pos,
1882 main_pen,
1883 avoids_floats
1884 );
1885
1886 // Re-layout IFC children with float context for correct text wrapping
1887 // Normal flow blocks WITH inline content need float context propagated
1888 if is_inline_fc && !avoids_floats {
1889 // Use cached floats if available (from previous layout passes),
1890 // otherwise use the floats positioned in this pass
1891 let floats_for_ifc = float_cache.get(&node_index).unwrap_or(&float_context);
1892
1893 debug_info!(
1894 ctx,
1895 "[layout_bfc] Re-layouting IFC child {} (normal flow) with parent's float context \
1896 at Y={}, child_cross_pos={}",
1897 child_index,
1898 main_pen,
1899 child_cross_pos
1900 );
1901 debug_info!(
1902 ctx,
1903 "[layout_bfc] Using {} floats (from cache: {})",
1904 floats_for_ifc.floats.len(),
1905 float_cache.contains_key(&node_index)
1906 );
1907
1908 // Translate float coordinates from BFC-relative to IFC-relative
1909 // The IFC child is positioned at (child_cross_pos, main_pen) in BFC coordinates
1910 // Floats need to be relative to the IFC's CONTENT-BOX origin (inside padding/border)
1911 let child_node = tree.get(child_index).ok_or(LayoutError::InvalidTree)?;
1912 let cbp = child_node.box_props.unpack();
1913 let padding_border_cross = cbp.padding.cross_start(writing_mode)
1914 + cbp.border.cross_start(writing_mode);
1915 let padding_border_main = cbp.padding.main_start(writing_mode)
1916 + cbp.border.main_start(writing_mode);
1917
1918 // Content-box origin in BFC coordinates
1919 let content_box_cross = child_cross_pos + padding_border_cross;
1920 let content_box_main = main_pen + padding_border_main;
1921
1922 debug_info!(
1923 ctx,
1924 "[layout_bfc] Border-box at ({}, {}), Content-box at ({}, {}), \
1925 padding+border=({}, {})",
1926 child_cross_pos,
1927 main_pen,
1928 content_box_cross,
1929 content_box_main,
1930 padding_border_cross,
1931 padding_border_main
1932 );
1933
1934 let mut ifc_floats = FloatingContext::default();
1935 for float_box in &floats_for_ifc.floats {
1936 // Convert float position from BFC coords to IFC CONTENT-BOX relative coords
1937 let float_rel_to_ifc = LogicalRect {
1938 origin: LogicalPosition {
1939 x: float_box.rect.origin.x - content_box_cross,
1940 y: float_box.rect.origin.y - content_box_main,
1941 },
1942 size: float_box.rect.size,
1943 };
1944
1945 debug_info!(
1946 ctx,
1947 "[layout_bfc] Float {:?}: BFC coords = {:?}, IFC-content-relative = {:?}",
1948 float_box.kind,
1949 float_box.rect,
1950 float_rel_to_ifc
1951 );
1952
1953 ifc_floats.add_float(float_box.kind, float_rel_to_ifc, float_box.margin);
1954 }
1955
1956 // Create a BfcState with IFC-relative float coordinates
1957 let mut bfc_state = BfcState {
1958 pen: LogicalPosition::zero(), // IFC starts at its own origin
1959 floats: ifc_floats.clone(),
1960 margins: MarginCollapseContext::default(),
1961 };
1962
1963 debug_info!(
1964 ctx,
1965 "[layout_bfc] Created IFC-relative FloatingContext with {} floats",
1966 ifc_floats.floats.len()
1967 );
1968
1969 // Get the IFC child's content-box size (after padding/border)
1970 let child_node = tree.get(child_index).ok_or(LayoutError::InvalidTree)?;
1971 let child_dom_id = child_node.dom_node_id;
1972
1973 // +spec:containing-block:a8ada9 - line box width determined by containing block and floats
1974 // For inline elements (display: inline), use containing block width as available
1975 // width. Inline elements flow within the containing block and wrap at its width.
1976 // CSS 2.2 § 10.3.1: For inline elements, available width = containing block width.
1977 let display = get_display_property(ctx.styled_dom, child_dom_id).unwrap_or_default();
1978 let child_content_size = if display == LayoutDisplay::Inline {
1979 // Inline elements use the containing block's content-box width
1980 LogicalSize::new(
1981 children_containing_block_size.width,
1982 children_containing_block_size.height,
1983 )
1984 } else {
1985 // Block-level elements use their own content-box
1986 child_node.box_props.inner_size(child_size, writing_mode)
1987 };
1988
1989 debug_info!(
1990 ctx,
1991 "[layout_bfc] IFC child size: border-box={:?}, content-box={:?}",
1992 child_size,
1993 child_content_size
1994 );
1995
1996 // Create new constraints with float context
1997 // IMPORTANT: Use the child's CONTENT-BOX width, not the BFC width!
1998 let ifc_constraints = LayoutConstraints {
1999 available_size: child_content_size,
2000 bfc_state: Some(&mut bfc_state),
2001 writing_mode,
2002 writing_mode_ctx: constraints.writing_mode_ctx,
2003 text_align: constraints.text_align,
2004 containing_block_size: constraints.containing_block_size,
2005 available_width_type: Text3AvailableSpace::Definite(child_content_size.width),
2006 };
2007
2008 // Re-layout the IFC with float awareness
2009 // This will pass floats as exclusion zones to text3 for line wrapping
2010 let ifc_result = layout_formatting_context(
2011 ctx,
2012 tree,
2013 text_cache,
2014 child_index,
2015 &ifc_constraints,
2016 float_cache,
2017 )?;
2018
2019 // DON'T update used_size - the box keeps its full width!
2020 // Only the text layout inside changes to wrap around floats
2021
2022 debug_info!(
2023 ctx,
2024 "[layout_bfc] IFC child {} re-layouted with float context (text will wrap, box \
2025 stays full width)",
2026 child_index
2027 );
2028
2029 // NOTE: We do NOT merge inline-block positions from the IFC's output.positions here!
2030 // The IFC's inline-block children will be correctly positioned when
2031 // calculate_layout_for_subtree recursively processes the IFC node (child_index).
2032 // At that point, layout_ifc will be called again, and the inline-block positions
2033 // will be relative to the IFC's content-box, which is what we want.
2034 //
2035 // Merging them here would cause them to be processed by process_inflow_child
2036 // with the BFC's content-box position (self_content_box_pos of the BFC),
2037 // resulting in incorrect absolute positions.
2038 }
2039
2040 output.positions.insert(child_index, final_pos);
2041
2042 // CSS margin collapse: escaped margins are handled via accumulated_top_margin
2043 // at the START of layout, not by adjusting positions after layout.
2044 // We simply advance by the child's actual size.
2045 main_pen += child_size.main(writing_mode);
2046 has_content = true;
2047
2048 // Update last margin for next sibling
2049 // CSS 2.2 § 8.3.1: The bottom margin of this box will collapse with the top margin
2050 // of the next sibling (if no clearance or blockers intervene)
2051 // element (between prev sibling's bottom and this element's top margin). The cleared
2052 // element's bottom margin is still available for normal collapsing with the next sibling.
2053 // CSS 2.2 § 9.5.2: "Clearance inhibits margin collapsing and acts as spacing above
2054 // the margin-top of an element."
2055 last_margin_bottom = child_margin_bottom;
2056
2057 debug_info!(
2058 ctx,
2059 "[layout_bfc] Child {} positioned at final_pos={:?}, size={:?}, advanced main_pen to \
2060 {}, last_margin_bottom={}, clearance_applied={}",
2061 child_index,
2062 final_pos,
2063 child_size,
2064 main_pen,
2065 last_margin_bottom,
2066 clearance_applied
2067 );
2068
2069 // Track the maximum cross-axis size to determine the BFC's overflow size.
2070 let child_cross_extent =
2071 child_cross_pos + child_size.cross(writing_mode) + child_margin.cross_end(writing_mode);
2072 max_cross_size = max_cross_size.max(child_cross_extent);
2073 }
2074
2075 // Store the float context in cache for future layout passes
2076 // This happens after ALL children (floats and normal) have been positioned
2077 debug_info!(
2078 ctx,
2079 "[layout_bfc] Storing {} floats in cache for node {}",
2080 float_context.floats.len(),
2081 node_index
2082 );
2083 float_cache.insert(node_index, float_context.clone());
2084
2085 // PHASE 3: Parent-Child Bottom Margin Escape
2086 let mut escaped_top_margin = None;
2087 let mut escaped_bottom_margin = None;
2088
2089 // Handle top margin escape
2090 if top_margin_escaped {
2091 // First child's margin escaped through parent
2092 escaped_top_margin = Some(accumulated_top_margin);
2093 debug_info!(
2094 ctx,
2095 "[layout_bfc] Returning escaped top margin: accumulated={}, node={}",
2096 accumulated_top_margin,
2097 node_index
2098 );
2099 } else if !top_margin_resolved && accumulated_top_margin > 0.0 {
2100 // No content was positioned, all margins accumulated (empty blocks)
2101 escaped_top_margin = Some(accumulated_top_margin);
2102 debug_info!(
2103 ctx,
2104 "[layout_bfc] Escaping top margin (no content): accumulated={}, node={}",
2105 accumulated_top_margin,
2106 node_index
2107 );
2108 } else {
2109 // Don't set escaped_top_margin = Some(0) — that would override the child's
2110 // own margin (e.g., 30px) with 0 during sibling collapse.
2111 debug_info!(
2112 ctx,
2113 "[layout_bfc] NOT escaping top margin: top_margin_resolved={}, escaped={}, \
2114 accumulated={}, node={}",
2115 top_margin_resolved,
2116 top_margin_escaped,
2117 accumulated_top_margin,
2118 node_index
2119 );
2120 }
2121
2122 // Handle bottom margin escape
2123 if let Some(last_idx) = last_child_index {
2124 let last_child = tree.get(last_idx).ok_or(LayoutError::InvalidTree)?;
2125 let last_child_bp = last_child.box_props.unpack();
2126 let last_has_bottom_blocker =
2127 has_margin_collapse_blocker(&last_child_bp, writing_mode, false);
2128
2129 debug_info!(
2130 ctx,
2131 "[layout_bfc] Bottom margin for node {}: parent_has_bottom_blocker={}, \
2132 last_has_bottom_blocker={}, last_margin_bottom={}, main_pen_before={}",
2133 node_index,
2134 parent_has_bottom_blocker,
2135 last_has_bottom_blocker,
2136 last_margin_bottom,
2137 main_pen
2138 );
2139
2140 if !parent_has_bottom_blocker && !last_has_bottom_blocker && has_content {
2141 // Last child's bottom margin can escape
2142 let collapsed_bottom = collapse_margins(parent_margin_bottom, last_margin_bottom);
2143 escaped_bottom_margin = Some(collapsed_bottom);
2144 debug_info!(
2145 ctx,
2146 "[layout_bfc] Bottom margin ESCAPED for node {}: collapsed={}",
2147 node_index,
2148 collapsed_bottom
2149 );
2150 // Don't add last_margin_bottom to pen (it escaped)
2151 } else {
2152 // Can't escape: add to pen
2153 main_pen += last_margin_bottom;
2154 // NOTE: We do NOT add parent_margin_bottom to main_pen here!
2155 // parent_margin_bottom is added OUTSIDE the content-box (in the margin-box)
2156 // The content-box height should only include children's content and margins
2157 debug_info!(
2158 ctx,
2159 "[layout_bfc] Bottom margin BLOCKED for node {}: added last_margin_bottom={}, \
2160 main_pen_after={}",
2161 node_index,
2162 last_margin_bottom,
2163 main_pen
2164 );
2165 }
2166 } else {
2167 // No children: just use parent's margins
2168 if !top_margin_resolved {
2169 main_pen += parent_margin_top;
2170 }
2171 main_pen += parent_margin_bottom;
2172 }
2173
2174 // CRITICAL: If this is a root node (no parent), apply escaped margins directly
2175 // instead of propagating them upward (since there's no parent to receive them)
2176 let is_root_node = node.parent.is_none();
2177 if is_root_node {
2178 if let Some(top) = escaped_top_margin {
2179 // Adjust all child positions downward by the escaped top margin
2180 for (_, pos) in output.positions.iter_mut() {
2181 let current_main = pos.main(writing_mode);
2182 *pos = LogicalPosition::from_main_cross(
2183 current_main + top,
2184 pos.cross(writing_mode),
2185 writing_mode,
2186 );
2187 }
2188 main_pen += top;
2189 }
2190 if let Some(bottom) = escaped_bottom_margin {
2191 main_pen += bottom;
2192 }
2193 // For root nodes, don't propagate margins further
2194 escaped_top_margin = None;
2195 escaped_bottom_margin = None;
2196 }
2197
2198 // CSS 2.2 § 9.5: Floats don't contribute to container height with overflow:visible
2199 //
2200 // However, browsers DO expand containers to contain floats in specific cases:
2201 //
2202 // 1. If there's NO in-flow content (main_pen == 0), floats determine height
2203 // 2. If container establishes a BFC (overflow != visible)
2204 //
2205 // In this case, we have in-flow content (main_pen > 0) and overflow:visible,
2206 // so floats should NOT expand the container. Their margins can "bleed" beyond
2207 // the container boundaries into the parent.
2208 //
2209 // This matches Chrome/Firefox behavior where float margins escape through
2210 // the container's padding when there's existing in-flow content.
2211
2212 // +spec:block-formatting-context:7954a2 - 10.6.3: auto height for block-level non-replaced elements in normal flow
2213 // Content-box Height Calculation
2214 //
2215 // CSS 2.2 § 8.3.1: "The top border edge of the box is defined to coincide with
2216 // the top border edge of the [first] child" when margins collapse/escape.
2217 //
2218 // This means escaped margins do NOT contribute to the parent's content-box height.
2219 //
2220 // Calculation:
2221 //
2222 // main_pen = total vertical space used by all children and margins
2223 //
2224 // Components of main_pen:
2225 //
2226 // 1. Children's border-boxes (always included)
2227 // 2. Sibling collapsed margins (space BETWEEN children - part of content)
2228 // 3. First child's position (0 if margin escaped, margin_top if blocked)
2229 //
2230 // What to subtract:
2231 //
2232 // - total_escaped_top_margin: First child's margin that went to grandparent's space This
2233 // margin is OUTSIDE our content-box, so we must subtract it.
2234 //
2235 // What NOT to subtract:
2236 //
2237 // - total_sibling_margins: These are the gaps BETWEEN children, which are
2238 // legitimately part of our content area's layout space.
2239 //
2240 // Example with escaped margin:
2241 // <div class="parent" padding=0> <!-- Node 2 -->
2242 // <div class="child1" margin=30></div> <!-- Node 3, margin escapes -->
2243 // <div class="child2" margin=40></div> <!-- Node 5 -->
2244 // </div>
2245 //
2246 // Layout process:
2247 //
2248 // - Node 3 positioned at main_pen=0 (margin escaped)
2249 // - Node 3 size=140px → main_pen advances to 140
2250 // - Sibling collapse: max(30 child1 bottom, 40 child2 top) = 40px
2251 // - main_pen advances to 180
2252 // - Node 5 size=130px → main_pen advances to 310
2253 // - total_escaped_top_margin = 30
2254 // - total_sibling_margins = 40 (tracked but NOT subtracted)
2255 // - content_box_height = 310 - 30 = 280px ✓
2256 //
2257 // Previously, we calculated:
2258 //
2259 // content_box_height = main_pen - total_escaped_top_margin - total_sibling_margins
2260 //
2261 // This incorrectly subtracted sibling margins, making parent too small.
2262 // Sibling margins are *between* boxes (part of layout), not *outside* boxes
2263 // (like escaped margins).
2264
2265 // +spec:box-model:4eebed - auto height for BFC = top margin-edge of topmost child to bottom margin-edge of bottommost child
2266 // +spec:box-model:4eebed - auto height = top margin-edge of topmost child to bottom margin-edge of bottommost child
2267 // +spec:height-calculation:d65226 - §10.6.7 auto heights for BFC roots: block children use
2268 // margin-edge of topmost/bottommost, floats extend height if below content edge
2269 // +spec:positioning:1a05bb - 10.6.7 auto height for BFC roots: block children use margin edges,
2270 // abspos ignored (skipped in Pass 1/2), relative considered without offset (applied after layout),
2271 // floats whose bottom margin edge exceeds content edge expand height (below)
2272 // +spec:positioning:e6712c - Auto height for BFC: distance between top/bottom margin-edges of
2273 // block children (minus escaped margins), ignoring absolutely positioned children (skipped at
2274 // line ~966), considering relatively positioned boxes without offset (applied after layout),
2275 // and extending to include floats whose bottom margin edge exceeds content edge
2276 // +spec:positioning:f94d22 - 10.6.3: block-level non-replaced auto height = distance from top content edge to last in-flow child bottom margin edge (or zero)
2277 // CSS 2.2 §8.3.1: escaped margins (both top and bottom) don't contribute to parent height
2278 let mut content_box_height = main_pen - total_escaped_top_margin
2279 - escaped_bottom_margin.unwrap_or(0.0);
2280
2281 // +spec:block-formatting-context:f73d3e - BFC root grows to fully contain its floats; floats from outside cannot protrude in
2282 // whose bottom margin edge exceeds bottom content edge; only floats participating
2283 // in this BFC are counted (not floats inside abspos descendants or nested BFCs)
2284 // +spec:box-model:1d4798 - auto height includes floats whose bottom margin edge exceeds content edge
2285 // only floats participating in this BFC are counted (not floats inside abspos descendants or nested BFCs)
2286 if is_bfc_root {
2287 for float_box in &float_context.floats {
2288 let float_bottom_margin_edge = float_box.rect.origin.main(writing_mode)
2289 + float_box.rect.size.main(writing_mode)
2290 + float_box.margin.main_end(writing_mode);
2291 if float_bottom_margin_edge > content_box_height {
2292 content_box_height = float_bottom_margin_edge;
2293 }
2294 }
2295 }
2296
2297 // +spec:display-contents:f6de1a - content height overflow tracked via overflow_size
2298 // +spec:overflow:043182 - overflow computed from box bounds + children overflow
2299 output.overflow_size =
2300 LogicalSize::from_main_cross(content_box_height, max_cross_size, writing_mode);
2301
2302 debug_info!(
2303 ctx,
2304 "[layout_bfc] FINAL for node {}: main_pen={}, total_escaped_top={}, \
2305 total_sibling_margins={}, content_box_height={}",
2306 node_index,
2307 main_pen,
2308 total_escaped_top_margin,
2309 total_sibling_margins,
2310 content_box_height
2311 );
2312
2313 // +spec:inline-formatting-context:2227a4 - atomic inline baseline for inline-block/inline-table
2314 // Baseline calculation would happen here in a full implementation.
2315 // CSS2 §10.8.1: For inline-block, baseline is the baseline of the last
2316 // line box in normal flow, or the bottom margin edge if no line boxes.
2317 output.baseline = None;
2318
2319 // Store escaped margins in the LayoutNode for use by parent
2320 if let Some(warm_mut) = tree.warm_mut(node_index) {
2321 warm_mut.escaped_top_margin = escaped_top_margin;
2322 warm_mut.escaped_bottom_margin = escaped_bottom_margin;
2323 }
2324
2325 if let Some(warm_mut) = tree.warm_mut(node_index) {
2326 warm_mut.baseline = output.baseline;
2327 }
2328
2329 Ok(BfcLayoutResult {
2330 output,
2331 escaped_top_margin,
2332 escaped_bottom_margin,
2333 })
2334}
2335
2336// Inline Formatting Context (CSS 2.2 § 9.4.2)
2337// +spec:display-property:ede6f4 - inline layout: mixed stream of text and inline-level boxes
2338
2339/// Lays out an Inline Formatting Context (IFC) by delegating to the `text3` engine.
2340///
2341/// This function acts as a bridge between the box-tree world of `solver3` and the
2342/// rich text layout world of `text3`. Its responsibilities are:
2343///
2344/// 1. **Collect Content**: Traverse the direct children of the IFC root and convert them into a
2345/// `Vec<InlineContent>`, the input format for `text3`. This involves:
2346///
2347/// - Recursively laying out `inline-block` children to determine their final size and baseline,
2348/// which are then passed to `text3` as opaque objects.
2349/// - Extracting raw text runs from inline text nodes.
2350///
2351/// 2. **Translate Constraints**: Convert the `LayoutConstraints` (available space, floats) from
2352/// `solver3` into the more detailed `UnifiedConstraints` that `text3` requires.
2353///
2354/// 3. **Invoke Text Layout**: Call the `text3` cache's `layout_flow` method to perform the complex
2355/// tasks of BIDI analysis, shaping, line breaking, justification, and vertical alignment.
2356/// +spec:display-property:e96c82 - inline formatting context: flow of elements/text wrapped into lines
2357///
2358/// 4. **Integrate Results**: Process the `UnifiedLayout` returned by `text3`:
2359///
2360/// - Store the rich layout result on the IFC root `LayoutNode` for the display list generation
2361/// pass.
2362/// - Update the `positions` map for all `inline-block` children based on the positions
2363/// calculated by `text3`.
2364/// - Extract the final overflow size and baseline for the IFC root itself
2365// NOTE(writing-modes): The IFC currently assumes inline direction = horizontal
2366// and block direction = vertical. In vertical writing modes, line boxes would
2367// stack horizontally and inline content would flow vertically. The writing mode
2368// is now available via constraints.writing_mode_ctx for agents to use when
2369// implementing vertical text layout in the text3 engine.
2370// +spec:display-property:574e7b - text-box-trim for inline boxes trims block-end to content edge (TODO: implement trimming per text-box-edge metric)
2371// +spec:display-property:da284a - IFC: flow inline-level boxes into line boxes, size/position each fragment
2372// +spec:inline-formatting-context:275f64 - IFC: boxes laid out horizontally into line boxes, respecting margins/borders/padding
2373fn layout_ifc<T: ParsedFontTrait>(
2374 ctx: &mut LayoutContext<'_, T>,
2375 text_cache: &mut crate::font_traits::TextLayoutCache,
2376 tree: &mut LayoutTree,
2377 node_index: usize,
2378 constraints: &LayoutConstraints,
2379) -> Result<LayoutOutput> {
2380 let ifc_start = (ctx.get_system_time_fn.cb)();
2381
2382 let float_count = constraints
2383 .bfc_state
2384 .as_ref()
2385 .map(|s| s.floats.floats.len())
2386 .unwrap_or(0);
2387 debug_info!(
2388 ctx,
2389 "[layout_ifc] ENTRY: node_index={}, has_bfc_state={}, float_count={}",
2390 node_index,
2391 constraints.bfc_state.is_some(),
2392 float_count
2393 );
2394 debug_ifc_layout!(ctx, "CALLED for node_index={}", node_index);
2395
2396 // +spec:display-property:7f3c1d - Anonymous inline boxes: text directly in block containers treated as anonymous inline elements in IFC
2397 // +spec:display-property:5a795c - root inline box: block container generates anonymous inline box holding all inline-level contents, inheriting from parent
2398 // For anonymous boxes, we need to find the DOM ID from a parent or child
2399 // CSS 2.2 § 9.2.1.1: Anonymous boxes inherit properties from their enclosing box
2400 let node = tree.get(node_index).ok_or(LayoutError::InvalidTree)?;
2401 let ifc_root_dom_id = match node.dom_node_id {
2402 Some(id) => id,
2403 None => {
2404 // Anonymous box - get DOM ID from parent or first child with DOM ID
2405 let parent_dom_id = node
2406 .parent
2407 .and_then(|p| tree.get(p))
2408 .and_then(|n| n.dom_node_id);
2409
2410 if let Some(id) = parent_dom_id {
2411 id
2412 } else {
2413 // Try to find DOM ID from first child
2414 tree.children(node_index)
2415 .iter()
2416 .filter_map(|&child_idx| tree.get(child_idx))
2417 .filter_map(|n| n.dom_node_id)
2418 .next()
2419 .ok_or(LayoutError::InvalidTree)?
2420 }
2421 }
2422 };
2423
2424 debug_ifc_layout!(ctx, "ifc_root_dom_id={:?}", ifc_root_dom_id);
2425
2426 // +spec:display-property:a469a6 - line boxes created as needed for inline-level content in IFC
2427 // +spec:display-property:f3c875 - calculate layout bounds (size contributions) of each inline-level box
2428 // Phase 1: Collect and measure all inline-level children.
2429 let phase1_start = (ctx.get_system_time_fn.cb)();
2430 let (inline_content, child_map) =
2431 collect_and_measure_inline_content(ctx, text_cache, tree, node_index, constraints)?;
2432 let _phase1_time = (ctx.get_system_time_fn.cb)().duration_since(&phase1_start);
2433
2434 debug_info!(
2435 ctx,
2436 "[layout_ifc] Collected {} inline content items for node {}",
2437 inline_content.len(),
2438 node_index
2439 );
2440 if inline_content.len() > 10 {
2441 let _text_count = inline_content.iter().filter(|i| matches!(i, InlineContent::Text(_))).count();
2442 let _shape_count = inline_content.iter().filter(|i| matches!(i, InlineContent::Shape(_))).count();
2443 }
2444 for (i, item) in inline_content.iter().enumerate() {
2445 match item {
2446 InlineContent::Text(run) => debug_info!(ctx, " [{}] Text: '{}'", i, run.text),
2447 InlineContent::Marker {
2448 run,
2449 position_outside,
2450 } => debug_info!(
2451 ctx,
2452 " [{}] Marker: '{}' (outside={})",
2453 i,
2454 run.text,
2455 position_outside
2456 ),
2457 InlineContent::Shape(_) => debug_info!(ctx, " [{}] Shape", i),
2458 InlineContent::Image(_) => debug_info!(ctx, " [{}] Image", i),
2459 _ => debug_info!(ctx, " [{}] Other", i),
2460 }
2461 }
2462
2463 debug_ifc_layout!(
2464 ctx,
2465 "Collected {} inline content items",
2466 inline_content.len()
2467 );
2468
2469 if inline_content.is_empty() {
2470 debug_warning!(ctx, "inline_content is empty, returning default output!");
2471 return Ok(LayoutOutput::default());
2472 }
2473
2474 // === Phase 2d: IFC incremental relayout decision tree ===
2475 //
2476 // Check if a cached layout exists with matching constraints. If so,
2477 // try incremental relayout (GlyphSwap or LineShift) before falling
2478 // back to full layout_flow().
2479 {
2480 let cached_ifc = tree
2481 .warm(node_index)
2482 .and_then(|n| n.inline_layout_result.as_ref());
2483
2484 if let Some(cached) = cached_ifc {
2485 if let Some(ref line_breaks) = cached.line_breaks {
2486 // Collect per-item advance widths from cached metrics
2487 let old_advances: Vec<f32> = cached.item_metrics.iter()
2488 .map(|m| m.advance_width)
2489 .collect();
2490
2491 // Cache-reuse fast path. Real incremental relayout for text
2492 // edits lives in LayoutWindow::try_incremental_text_relayout
2493 // (window.rs) — it has the newly-shaped items and the edited
2494 // node id, so it can compute real dirty_item_indices and
2495 // take the GlyphSwap / LineShift branches. Here we only
2496 // know the IFC is being re-entered (e.g. viewport resize on
2497 // a static IFC); with nothing re-shaped yet, the best we can
2498 // do is "no items changed at this level" → trivial GlyphSwap
2499 // to return the cached layout unchanged.
2500 let result = crate::text3::cache::try_incremental_relayout(
2501 &[], // empty = no dirty items detected at this level
2502 &old_advances,
2503 &old_advances, // same advances since we haven't reshaped yet
2504 line_breaks,
2505 );
2506
2507 match result {
2508 crate::text3::cache::IncrementalRelayoutResult::GlyphSwap => {
2509 // No items changed — return cached layout directly
2510 debug_info!(ctx, "[layout_ifc] Phase 2d: GlyphSwap — reusing cached layout");
2511 let main_frag = &cached.layout;
2512 let frag_bounds = main_frag.bounds();
2513 let mut output = LayoutOutput::default();
2514 output.overflow_size = LogicalSize::new(frag_bounds.width, frag_bounds.height);
2515 output.baseline = main_frag.last_baseline();
2516 // Re-position inline-block children from cached layout
2517 for positioned_item in &main_frag.items {
2518 if let ShapedItem::Object { source, .. } = &positioned_item.item {
2519 if let Some(&child_node_index) = child_map.get(source) {
2520 output.positions.insert(child_node_index, LogicalPosition {
2521 x: positioned_item.position.x,
2522 y: positioned_item.position.y,
2523 });
2524 }
2525 }
2526 }
2527 return Ok(output);
2528 }
2529 _ => {
2530 // Fall through to full layout_flow
2531 }
2532 }
2533 }
2534 }
2535 }
2536
2537 // Phase 2: Translate constraints and define a single layout fragment for text3.
2538 let text3_constraints =
2539 translate_to_text3_constraints(ctx, constraints, ctx.styled_dom, ifc_root_dom_id);
2540
2541 // Clone constraints for caching (before they're moved into fragments)
2542 let cached_constraints = text3_constraints.clone();
2543
2544 debug_info!(
2545 ctx,
2546 "[layout_ifc] CALLING text_cache.layout_flow for node {} with {} exclusions",
2547 node_index,
2548 text3_constraints.shape_exclusions.len()
2549 );
2550
2551 let fragments = vec![LayoutFragment {
2552 id: "main".to_string(),
2553 constraints: text3_constraints,
2554 }];
2555
2556 // Phase 3: Invoke the text layout engine.
2557 // Get pre-loaded fonts from font manager (fonts should be loaded before layout)
2558 let phase3_start = (ctx.get_system_time_fn.cb)();
2559 let loaded_fonts = ctx.font_manager.get_loaded_fonts();
2560 let text_layout_result = match text_cache.layout_flow(
2561 &inline_content,
2562 &[],
2563 &fragments,
2564 &ctx.font_manager.font_chain_cache,
2565 &ctx.font_manager.fc_cache,
2566 &loaded_fonts,
2567 ctx.debug_messages,
2568 ) {
2569 Ok(result) => result,
2570 Err(e) => {
2571 // Font errors should not stop layout of other elements.
2572 // Log the error and return a zero-sized layout.
2573 debug_warning!(ctx, "Text layout failed: {:?}", e);
2574 debug_warning!(
2575 ctx,
2576 "Continuing with zero-sized layout for node {}",
2577 node_index
2578 );
2579
2580 let mut output = LayoutOutput::default();
2581 output.overflow_size = LogicalSize::new(0.0, 0.0);
2582 return Ok(output);
2583 }
2584 };
2585 let _phase3_time = (ctx.get_system_time_fn.cb)().duration_since(&phase3_start);
2586 let _total_ifc_time = (ctx.get_system_time_fn.cb)().duration_since(&ifc_start);
2587
2588 // Phase 4: Integrate results back into the solver3 layout tree.
2589 let mut output = LayoutOutput::default();
2590
2591 debug_ifc_layout!(
2592 ctx,
2593 "text_layout_result has {} fragment_layouts",
2594 text_layout_result.fragment_layouts.len()
2595 );
2596
2597 if let Some(main_frag) = text_layout_result.fragment_layouts.get("main") {
2598 let frag_bounds = main_frag.bounds();
2599 debug_ifc_layout!(
2600 ctx,
2601 "Found 'main' fragment with {} items, bounds={}x{}",
2602 main_frag.items.len(),
2603 frag_bounds.width,
2604 frag_bounds.height
2605 );
2606 debug_ifc_layout!(ctx, "Storing inline_layout_result on node {}", node_index);
2607
2608 // Determine if we should store this layout result using the new
2609 // CachedInlineLayout system. The key insight is that inline layouts
2610 // depend on available width:
2611 //
2612 // - Min-content measurement uses width ≈ 0 (maximum line wrapping)
2613 // - Max-content measurement uses width = ∞ (no line wrapping)
2614 // - Final layout uses the actual column/container width
2615 //
2616 // We must track which constraint type was used, otherwise a min-content
2617 // measurement would incorrectly be reused for final rendering.
2618 let has_floats = constraints
2619 .bfc_state
2620 .as_ref()
2621 .map(|s| !s.floats.floats.is_empty())
2622 .unwrap_or(false);
2623 let current_width_type = constraints.available_width_type;
2624
2625 let warm_node = tree.warm_mut(node_index).ok_or(LayoutError::InvalidTree)?;
2626
2627 let should_store = match &warm_node.inline_layout_result {
2628 None => {
2629 // No cached result - always store
2630 debug_info!(
2631 ctx,
2632 "[layout_ifc] Storing NEW inline_layout_result for node {} (width_type={:?}, \
2633 has_floats={})",
2634 node_index,
2635 current_width_type,
2636 has_floats
2637 );
2638 true
2639 }
2640 Some(cached) => {
2641 // Check if the new result should replace the cached one
2642 if cached.should_replace_with(current_width_type, has_floats) {
2643 debug_info!(
2644 ctx,
2645 "[layout_ifc] REPLACING inline_layout_result for node {} (old: \
2646 width={:?}, floats={}) with (new: width={:?}, floats={})",
2647 node_index,
2648 cached.available_width,
2649 cached.has_floats,
2650 current_width_type,
2651 has_floats
2652 );
2653 true
2654 } else {
2655 debug_info!(
2656 ctx,
2657 "[layout_ifc] KEEPING cached inline_layout_result for node {} (cached: \
2658 width={:?}, floats={}, new: width={:?}, floats={})",
2659 node_index,
2660 cached.available_width,
2661 cached.has_floats,
2662 current_width_type,
2663 has_floats
2664 );
2665 false
2666 }
2667 }
2668 };
2669
2670 if should_store {
2671 warm_node.inline_layout_result = Some(CachedInlineLayout::new_with_constraints(
2672 main_frag.clone(),
2673 current_width_type,
2674 has_floats,
2675 cached_constraints.clone(),
2676 ));
2677 }
2678
2679 // Extract the overall size and baseline for the IFC root.
2680 // +spec:display-property:a0d0ab - IFC height = top of topmost line box to bottom of bottommost line box
2681 // +spec:display-property:a63b8f - baseline-source defaults to auto (last baseline for inline-block/IFC)
2682 output.overflow_size = LogicalSize::new(frag_bounds.width, frag_bounds.height);
2683 output.baseline = main_frag.last_baseline();
2684 warm_node.baseline = output.baseline;
2685
2686 // +spec:box-model:929f42 - text-box-trim: trim half-leading from first/last formatted line
2687 // +spec:box-model:02e0f9 - text-box-trim: trim-end and trim-both, no effect with non-zero padding/border
2688 //
2689 // CSS Inline 3 § 6.2: For block containers, trim the block-start/block-end side
2690 // of the first/last formatted line. If there is intervening non-zero padding or
2691 // borders, there is no effect. Does not apply to flex, grid, or table contexts.
2692 let ifc_node_state = &ctx.styled_dom.styled_nodes.as_container()[ifc_root_dom_id].styled_node_state;
2693 // Fast path: if no node in the DOM declared text-box-trim, the cascade
2694 // walk would always return None → skip it.
2695 let text_box_trim = {
2696 let skip = ctx.styled_dom
2697 .css_property_cache
2698 .ptr
2699 .compact_cache
2700 .as_ref()
2701 .map(|cc| cc.dom_declared_flags & azul_css::compact_cache::DOM_HAS_TEXT_BOX_TRIM == 0)
2702 .unwrap_or(false);
2703 if skip {
2704 StyleTextBoxTrim::None
2705 } else {
2706 get_text_box_trim_property(ctx.styled_dom, ifc_root_dom_id, ifc_node_state)
2707 .unwrap_or(StyleTextBoxTrim::None)
2708 }
2709 };
2710
2711 if text_box_trim != StyleTextBoxTrim::None && !main_frag.items.is_empty() {
2712 // Half-leading = (line-height - (ascent + descent)) / 2
2713 let half_leading = (cached_constraints.resolved_line_height()
2714 - (cached_constraints.strut_ascent + cached_constraints.strut_descent))
2715 / 2.0;
2716 let half_leading = half_leading.max(0.0);
2717
2718 // Check for intervening non-zero padding/border on block-start (top)
2719 let has_pad_or_border_top = match get_css_padding_top(ctx.styled_dom, ifc_root_dom_id, ifc_node_state) {
2720 MultiValue::Exact(pv) => pv.number.get() != 0.0,
2721 _ => false,
2722 } || match get_css_border_top_width(ctx.styled_dom, ifc_root_dom_id, ifc_node_state) {
2723 MultiValue::Exact(pv) => pv.number.get() != 0.0,
2724 _ => false,
2725 };
2726
2727 // Check for intervening non-zero padding/border on block-end (bottom)
2728 let has_pad_or_border_bottom = match get_css_padding_bottom(ctx.styled_dom, ifc_root_dom_id, ifc_node_state) {
2729 MultiValue::Exact(pv) => pv.number.get() != 0.0,
2730 _ => false,
2731 } || match get_css_border_bottom_width(ctx.styled_dom, ifc_root_dom_id, ifc_node_state) {
2732 MultiValue::Exact(pv) => pv.number.get() != 0.0,
2733 _ => false,
2734 };
2735
2736 let trim_start = matches!(text_box_trim, StyleTextBoxTrim::TrimStart | StyleTextBoxTrim::TrimBoth)
2737 && !has_pad_or_border_top;
2738 let trim_end = matches!(text_box_trim, StyleTextBoxTrim::TrimEnd | StyleTextBoxTrim::TrimBoth)
2739 && !has_pad_or_border_bottom;
2740
2741 let mut height_reduction = 0.0;
2742 if trim_start && half_leading > 0.0 {
2743 height_reduction += half_leading;
2744 }
2745 if trim_end && half_leading > 0.0 {
2746 height_reduction += half_leading;
2747 }
2748
2749 if height_reduction > 0.0 {
2750 output.overflow_size.height = (output.overflow_size.height - height_reduction).max(0.0);
2751 }
2752 }
2753
2754 // Position all the inline-block children based on text3's calculations.
2755 // [CoordinateSpace::Parent] - positions are relative to IFC's content-box (0,0)
2756 for positioned_item in &main_frag.items {
2757 if let ShapedItem::Object { source, content, .. } = &positioned_item.item {
2758 if let Some(&child_node_index) = child_map.get(source) {
2759 // new_relative_pos is [CoordinateSpace::Parent] - relative to this IFC's content-box
2760 let new_relative_pos = LogicalPosition {
2761 x: positioned_item.position.x,
2762 y: positioned_item.position.y,
2763 };
2764 output.positions.insert(child_node_index, new_relative_pos);
2765 }
2766 }
2767 }
2768 }
2769
2770 Ok(output)
2771}
2772
2773fn translate_taffy_size(size: LogicalSize) -> TaffySize<Option<f32>> {
2774 TaffySize {
2775 width: Some(size.width),
2776 height: Some(size.height),
2777 }
2778}
2779
2780/// Helper: Convert StyleFontStyle to text3::cache::FontStyle
2781pub fn convert_font_style(style: StyleFontStyle) -> crate::font_traits::FontStyle {
2782 match style {
2783 StyleFontStyle::Normal => crate::font_traits::FontStyle::Normal,
2784 StyleFontStyle::Italic => crate::font_traits::FontStyle::Italic,
2785 StyleFontStyle::Oblique => crate::font_traits::FontStyle::Oblique,
2786 }
2787}
2788
2789/// Helper: Convert StyleFontWeight to FcWeight
2790pub fn convert_font_weight(weight: StyleFontWeight) -> FcWeight {
2791 match weight {
2792 StyleFontWeight::W100 => FcWeight::Thin,
2793 StyleFontWeight::W200 => FcWeight::ExtraLight,
2794 StyleFontWeight::W300 | StyleFontWeight::Lighter => FcWeight::Light,
2795 StyleFontWeight::Normal => FcWeight::Normal,
2796 StyleFontWeight::W500 => FcWeight::Medium,
2797 StyleFontWeight::W600 => FcWeight::SemiBold,
2798 StyleFontWeight::Bold => FcWeight::Bold,
2799 StyleFontWeight::W800 => FcWeight::ExtraBold,
2800 StyleFontWeight::W900 | StyleFontWeight::Bolder => FcWeight::Black,
2801 }
2802}
2803
2804/// Resolves a CSS size metric to pixels.
2805///
2806/// - `metric`: The CSS unit (px, pt, em, vw, etc.)
2807/// - `value`: The numeric value
2808/// - `containing_block_size`: Size of containing block (for percentage)
2809/// - `viewport_size`: Viewport dimensions (for vw, vh, vmin, vmax)
2810#[inline]
2811fn resolve_size_metric(
2812 metric: SizeMetric,
2813 value: f32,
2814 containing_block_size: f32,
2815 viewport_size: LogicalSize,
2816) -> f32 {
2817 match metric {
2818 SizeMetric::Px => value,
2819 SizeMetric::Pt => value * PT_TO_PX,
2820 SizeMetric::Percent => value / 100.0 * containing_block_size,
2821 SizeMetric::Em | SizeMetric::Rem => value * DEFAULT_FONT_SIZE,
2822 SizeMetric::Vw => value / 100.0 * viewport_size.width,
2823 SizeMetric::Vh => value / 100.0 * viewport_size.height,
2824 SizeMetric::Vmin => value / 100.0 * viewport_size.width.min(viewport_size.height),
2825 SizeMetric::Vmax => value / 100.0 * viewport_size.width.max(viewport_size.height),
2826 // In, Cm, Mm: convert to pixels using standard DPI (96)
2827 SizeMetric::In => value * 96.0,
2828 SizeMetric::Cm => value * 96.0 / 2.54,
2829 SizeMetric::Mm => value * 96.0 / 25.4,
2830 }
2831}
2832
2833pub fn translate_taffy_size_back(size: TaffySize<f32>) -> LogicalSize {
2834 LogicalSize {
2835 width: size.width,
2836 height: size.height,
2837 }
2838}
2839
2840pub fn translate_taffy_point_back(point: taffy::Point<f32>) -> LogicalPosition {
2841 LogicalPosition {
2842 x: point.x,
2843 y: point.y,
2844 }
2845}
2846
2847// +spec:block-formatting-context:40e03e - BFC root: block container establishing new BFC (contains floats, excludes external floats, suppresses margin collapsing)
2848/// Checks if a node establishes a new Block Formatting Context (BFC).
2849///
2850/// Per CSS 2.2 § 9.4.1, a BFC is established by:
2851/// - Floats (elements with float other than 'none')
2852/// - Absolutely positioned elements (position: absolute or fixed)
2853/// - Block containers that are not block boxes (e.g., inline-blocks, table-cells)
2854/// - Block boxes with 'overflow' other than 'visible' and 'clip'
2855/// - Elements with 'display: flow-root'
2856/// - Table cells, table captions, and inline-blocks
2857///
2858/// Normal flow block-level boxes do NOT establish a new BFC.
2859///
2860/// This is critical for correct float interaction: normal blocks should overlap floats
2861/// (not shrink around them), while their inline content wraps around floats.
2862// +spec:block-formatting-context:241d22 - block container establishes new BFC or continues parent's, based on overflow/position/float/display
2863// +spec:block-formatting-context:9fe441 - BFC establishment based on position, float, overflow, and display properties
2864// +spec:display-property:3c7369 - block boxes establishing independent FC create new BFC; flex containers already do; non-replaced inlines cannot
2865// +spec:positioning:1e94f6 - floats, abspos, inline-blocks/table-cells/table-captions, overflow!=visible establish new BFC
2866fn establishes_new_bfc<T: ParsedFontTrait>(ctx: &LayoutContext<'_, T>, node: &LayoutNodeHot, cold: Option<&LayoutNodeCold>) -> bool {
2867 // +spec:block-formatting-context:f39cd3 - table wrapper box establishes a BFC (CSS 2.2 §17.4)
2868 // Anonymous table wrapper boxes have no dom_node_id but must still establish BFC
2869 // +spec:height-calculation:e20498 - table wrapper box establishes BFC (CSS 2.2 §17.4)
2870 // +spec:positioning:b780d3 - Table wrapper box establishes BFC (CSS 2.2 § 17.4)
2871 if cold.and_then(|c| c.anonymous_type) == Some(AnonymousBoxType::TableWrapper) {
2872 return true;
2873 }
2874 let Some(dom_id) = node.dom_node_id else {
2875 return false;
2876 };
2877
2878 let node_state = &ctx.styled_dom.styled_nodes.as_container()[dom_id].styled_node_state;
2879
2880 // 1. Floats establish BFC
2881 let float_val = get_float(ctx.styled_dom, dom_id, node_state);
2882 if matches!(
2883 float_val,
2884 MultiValue::Exact(LayoutFloat::Left | LayoutFloat::Right)
2885 ) {
2886 return true;
2887 }
2888
2889 // +spec:positioning:69468c - absolute/fixed forces independent formatting context
2890 let position = crate::solver3::positioning::get_position_type(ctx.styled_dom, Some(dom_id));
2891 if matches!(position, LayoutPosition::Absolute | LayoutPosition::Fixed) {
2892 return true;
2893 }
2894
2895 // 3. Inline-blocks, table-cells, table-captions establish BFC
2896 let display = get_display_property(ctx.styled_dom, Some(dom_id));
2897 if matches!(
2898 display,
2899 MultiValue::Exact(
2900 LayoutDisplay::InlineBlock | LayoutDisplay::TableCell | LayoutDisplay::TableCaption
2901 )
2902 ) {
2903 return true;
2904 }
2905
2906 // 4. display: flow-root establishes BFC
2907 // +spec:display-property:14bae6 - flow-root establishes a formatting context that contains/excludes floats
2908 if matches!(display, MultiValue::Exact(LayoutDisplay::FlowRoot)) {
2909 return true;
2910 }
2911
2912 // +spec:overflow:0a944d - clip does NOT establish BFC; hidden/scroll/auto do establish BFC
2913 // +spec:overflow:631a4c - scroll containers establish independent formatting context (BFC)
2914 // +spec:overflow:f6a186 - overflow:clip does NOT establish BFC; use display:flow-root for that
2915 // +spec:overflow:717de1 - overflow != visible/clip establishes BFC per CSS 2.2 §9.4.1
2916 // +spec:positioning:6feb32 - overflow:clip does NOT establish new formatting context; hidden/scroll/auto do
2917 // 5. Block boxes with overflow other than 'visible' or 'clip' establish BFC
2918 // +spec:overflow:b34aef - Block boxes with overflow other than 'visible' or 'clip' establish BFC
2919 // Note: 'clip' does NOT establish BFC per CSS Overflow Module Level 3
2920 let overflow_x = get_overflow_x(ctx.styled_dom, dom_id, node_state);
2921 let overflow_y = get_overflow_y(ctx.styled_dom, dom_id, node_state);
2922
2923 let creates_bfc_via_overflow = |ov: &MultiValue<LayoutOverflow>| {
2924 matches!(
2925 ov,
2926 &MultiValue::Exact(
2927 LayoutOverflow::Hidden | LayoutOverflow::Scroll | LayoutOverflow::Auto
2928 )
2929 )
2930 };
2931
2932 if creates_bfc_via_overflow(&overflow_x) || creates_bfc_via_overflow(&overflow_y) {
2933 return true;
2934 }
2935
2936 // 6. Table, Flex, and Grid containers establish BFC (via FormattingContext)
2937 // +spec:block-formatting-context:f15b87 - display:table participates in a BFC
2938 if matches!(
2939 node.formatting_context,
2940 FormattingContext::Table | FormattingContext::Flex | FormattingContext::Grid
2941 ) {
2942 return true;
2943 }
2944
2945 // +spec:block-formatting-context:33e6cd - block container with different writing-mode than parent establishes independent BFC
2946 // CSS Writing Modes 4 § 3.2: if a block container has a different writing-mode
2947 // than its parent, its inner display type computes to flow-root (i.e., it establishes BFC).
2948 {
2949 let hierarchy = ctx.styled_dom.node_hierarchy.as_container();
2950 if let Some(parent_dom_id) = hierarchy[dom_id].parent_id() {
2951 let parent_state = &ctx.styled_dom.styled_nodes.as_container()[parent_dom_id].styled_node_state;
2952 let child_wm = get_writing_mode(ctx.styled_dom, dom_id, node_state).unwrap_or_default();
2953 let parent_wm = get_writing_mode(ctx.styled_dom, parent_dom_id, parent_state).unwrap_or_default();
2954 if child_wm != parent_wm {
2955 return true;
2956 }
2957 }
2958 }
2959
2960 // Normal flow block boxes do NOT establish BFC
2961 // NOTE: align-content != normal should also establish BFC per CSS-DISPLAY-3, but align-content is not yet implemented for block containers
2962 false
2963}
2964
2965// +spec:display-property:5e5420 - replaced element identification (glossary: replaced elements have natural dimensions, establish independent formatting context)
2966/// CSS 2.2 § 9.5: "The border box of a table, a block-level replaced element, or an element
2967/// in the normal flow that establishes a new block formatting context [...] must not overlap
2968/// the margin box of any floats in the same block formatting context as the element itself."
2969fn is_block_level_replaced<T: ParsedFontTrait>(ctx: &LayoutContext<'_, T>, node: &LayoutNodeHot) -> bool {
2970 let Some(dom_id) = node.dom_node_id else {
2971 return false;
2972 };
2973
2974 // Check display is block-level
2975 let display = get_display_property(ctx.styled_dom, Some(dom_id));
2976 let is_block_level = matches!(
2977 display,
2978 MultiValue::Exact(LayoutDisplay::Block | LayoutDisplay::ListItem | LayoutDisplay::FlowRoot)
2979 );
2980
2981 if !is_block_level {
2982 return false;
2983 }
2984
2985 // Check if the element is a replaced element (image, video, etc.)
2986 let node_data = &ctx.styled_dom.node_data.as_container()[dom_id];
2987 matches!(
2988 node_data.get_node_type(),
2989 NodeType::Image(_)
2990 )
2991}
2992
2993/// Translates solver3 layout constraints into the text3 engine's unified constraints.
2994fn translate_to_text3_constraints<'a, T: ParsedFontTrait>(
2995 ctx: &mut LayoutContext<'_, T>,
2996 constraints: &'a LayoutConstraints<'a>,
2997 styled_dom: &StyledDom,
2998 dom_id: NodeId,
2999) -> UnifiedConstraints {
3000 // DOM-level declared flags: if a bit is clear, no node in this DOM
3001 // declared the corresponding property → cascade walks always return
3002 // None, and we use the default value directly. All flags default to
3003 // "set" when there is no compact cache (paranoid fallback).
3004 use azul_css::compact_cache::{
3005 DOM_HAS_SHAPE_INSIDE, DOM_HAS_SHAPE_OUTSIDE, DOM_HAS_TEXT_JUSTIFY,
3006 DOM_HAS_TEXT_INDENT, DOM_HAS_COLUMN_COUNT, DOM_HAS_COLUMN_GAP,
3007 DOM_HAS_COLUMN_WIDTH,
3008 DOM_HAS_INITIAL_LETTER, DOM_HAS_INITIAL_LETTER_ALIGN,
3009 DOM_HAS_LINE_CLAMP, DOM_HAS_HANGING_PUNCTUATION,
3010 DOM_HAS_TEXT_COMBINE_UPRIGHT, DOM_HAS_EXCLUSION_MARGIN,
3011 DOM_HAS_SHAPE_MARGIN,
3012 DOM_HAS_HYPHENATION_LANGUAGE, DOM_HAS_UNICODE_BIDI,
3013 DOM_HAS_HYPHENS, DOM_HAS_WORD_BREAK, DOM_HAS_OVERFLOW_WRAP,
3014 DOM_HAS_LINE_BREAK, DOM_HAS_TEXT_ALIGN_LAST, DOM_HAS_LINE_HEIGHT,
3015 };
3016 let dom_declared = styled_dom
3017 .css_property_cache
3018 .ptr
3019 .compact_cache
3020 .as_ref()
3021 .map(|cc| cc.dom_declared_flags)
3022 .unwrap_or(!0u32);
3023
3024 // Convert floats into exclusion zones for text3 to flow around.
3025 let mut shape_exclusions = if let Some(ref bfc_state) = constraints.bfc_state {
3026 debug_info!(
3027 ctx,
3028 "[translate_to_text3] dom_id={:?}, converting {} floats to exclusions",
3029 dom_id,
3030 bfc_state.floats.floats.len()
3031 );
3032 bfc_state
3033 .floats
3034 .floats
3035 .iter()
3036 .enumerate()
3037 .map(|(i, float_box)| {
3038 let rect = crate::text3::cache::Rect {
3039 x: float_box.rect.origin.x,
3040 y: float_box.rect.origin.y,
3041 width: float_box.rect.size.width,
3042 height: float_box.rect.size.height,
3043 };
3044 debug_info!(
3045 ctx,
3046 "[translate_to_text3] Exclusion #{}: {:?} at ({}, {}) size {}x{}",
3047 i,
3048 float_box.kind,
3049 rect.x,
3050 rect.y,
3051 rect.width,
3052 rect.height
3053 );
3054 ShapeBoundary::Rectangle(rect)
3055 })
3056 .collect()
3057 } else {
3058 debug_info!(
3059 ctx,
3060 "[translate_to_text3] dom_id={:?}, NO bfc_state - no float exclusions",
3061 dom_id
3062 );
3063 Vec::new()
3064 };
3065
3066 debug_info!(
3067 ctx,
3068 "[translate_to_text3] dom_id={:?}, available_size={}x{}, shape_exclusions.len()={}",
3069 dom_id,
3070 constraints.available_size.width,
3071 constraints.available_size.height,
3072 shape_exclusions.len()
3073 );
3074
3075 // Map text-align and justify-content from CSS to text3 enums.
3076 let id = dom_id;
3077 let node_data = &styled_dom.node_data.as_container()[id];
3078 let node_state = &styled_dom.styled_nodes.as_container()[id].styled_node_state;
3079
3080 // Read CSS Shapes properties
3081 // For reference box, use the element's CSS height if available, otherwise available_size
3082 // This is important because available_size.height might be infinite during auto height
3083 // calculation
3084 let ref_box_height = if constraints.available_size.height.is_finite() {
3085 constraints.available_size.height
3086 } else {
3087 // Try to get explicit CSS height
3088 // NOTE: If height is infinite, we can't properly resolve % heights
3089 // This is a limitation - shape-inside with % heights requires finite containing block
3090 styled_dom
3091 .css_property_cache
3092 .ptr
3093 .get_height(node_data, &id, node_state)
3094 .and_then(|v| v.get_property())
3095 .and_then(|h| match h {
3096 LayoutHeight::Px(v) => {
3097 // Only accept absolute units (px, pt, in, cm, mm) - no %, em, rem
3098 // since we can't resolve relative units without proper context
3099 match v.metric {
3100 SizeMetric::Px => Some(v.number.get()),
3101 SizeMetric::Pt => Some(v.number.get() * PT_TO_PX),
3102 SizeMetric::In => Some(v.number.get() * 96.0),
3103 SizeMetric::Cm => Some(v.number.get() * 96.0 / 2.54),
3104 SizeMetric::Mm => Some(v.number.get() * 96.0 / 25.4),
3105 _ => None, // Ignore %, em, rem
3106 }
3107 }
3108 _ => None,
3109 })
3110 .unwrap_or(constraints.available_size.width) // Fallback: use width as height (square)
3111 };
3112
3113 let reference_box = crate::text3::cache::Rect {
3114 x: 0.0,
3115 y: 0.0,
3116 width: constraints.available_size.width,
3117 height: ref_box_height,
3118 };
3119
3120 // shape-inside: Text flows within the shape boundary
3121 debug_info!(ctx, "Checking shape-inside for node {:?}", id);
3122 debug_info!(
3123 ctx,
3124 "Reference box: {:?} (available_size height was: {})",
3125 reference_box,
3126 constraints.available_size.height
3127 );
3128
3129 let shape_boundaries = if dom_declared & DOM_HAS_SHAPE_INSIDE != 0 {
3130 styled_dom
3131 .css_property_cache
3132 .ptr
3133 .get_shape_inside(node_data, &id, node_state)
3134 .and_then(|v| {
3135 debug_info!(ctx, "Got shape-inside value: {:?}", v);
3136 v.get_property()
3137 })
3138 .and_then(|shape_inside| {
3139 debug_info!(ctx, "shape-inside property: {:?}", shape_inside);
3140 if let ShapeInside::Shape(css_shape) = shape_inside {
3141 debug_info!(
3142 ctx,
3143 "Converting CSS shape to ShapeBoundary: {:?}",
3144 css_shape
3145 );
3146 let boundary =
3147 ShapeBoundary::from_css_shape(css_shape, reference_box, ctx.debug_messages);
3148 debug_info!(ctx, "Created ShapeBoundary: {:?}", boundary);
3149 Some(vec![boundary])
3150 } else {
3151 debug_info!(ctx, "shape-inside is None");
3152 None
3153 }
3154 })
3155 .unwrap_or_default()
3156 } else {
3157 Vec::new()
3158 };
3159
3160 debug_info!(
3161 ctx,
3162 "Final shape_boundaries count: {}",
3163 shape_boundaries.len()
3164 );
3165
3166 // shape-outside: Text wraps around the shape (adds to exclusions)
3167 debug_info!(ctx, "Checking shape-outside for node {:?}", id);
3168 if dom_declared & DOM_HAS_SHAPE_OUTSIDE != 0 {
3169 if let Some(shape_outside_value) = styled_dom
3170 .css_property_cache
3171 .ptr
3172 .get_shape_outside(node_data, &id, node_state)
3173 {
3174 debug_info!(ctx, "Got shape-outside value: {:?}", shape_outside_value);
3175 if let Some(shape_outside) = shape_outside_value.get_property() {
3176 debug_info!(ctx, "shape-outside property: {:?}", shape_outside);
3177 if let ShapeOutside::Shape(css_shape) = shape_outside {
3178 debug_info!(
3179 ctx,
3180 "Converting CSS shape-outside to ShapeBoundary: {:?}",
3181 css_shape
3182 );
3183 let boundary =
3184 ShapeBoundary::from_css_shape(css_shape, reference_box, ctx.debug_messages);
3185 debug_info!(ctx, "Created ShapeBoundary (exclusion): {:?}", boundary);
3186 shape_exclusions.push(boundary);
3187 }
3188 }
3189 } else {
3190 debug_info!(ctx, "No shape-outside value found");
3191 }
3192 }
3193
3194 // TODO: clip-path will be used for rendering clipping (not text layout)
3195
3196 let writing_mode = get_writing_mode(styled_dom, id, node_state).unwrap_or_default();
3197
3198 let text_align = get_text_align(styled_dom, id, node_state).unwrap_or_default();
3199
3200 let text_justify = if dom_declared & DOM_HAS_TEXT_JUSTIFY != 0 {
3201 styled_dom
3202 .css_property_cache
3203 .ptr
3204 .get_text_justify(node_data, &id, node_state)
3205 .and_then(|s| s.get_property().copied())
3206 .unwrap_or_default()
3207 } else {
3208 Default::default()
3209 };
3210
3211 // Get font-size for resolving line-height
3212 // Use helper function which checks dependency chain first
3213 let font_size = get_element_font_size(styled_dom, id, node_state);
3214
3215 let line_height_value = if dom_declared & DOM_HAS_LINE_HEIGHT != 0 {
3216 styled_dom
3217 .css_property_cache
3218 .ptr
3219 .get_line_height(node_data, &id, node_state)
3220 .and_then(|s| s.get_property().cloned())
3221 .unwrap_or_default()
3222 } else {
3223 Default::default()
3224 };
3225
3226 let hyphenation = if dom_declared & DOM_HAS_HYPHENS != 0 {
3227 styled_dom
3228 .css_property_cache
3229 .ptr
3230 .get_hyphens(node_data, &id, node_state)
3231 .and_then(|s| s.get_property().copied())
3232 .unwrap_or_default()
3233 } else {
3234 Default::default()
3235 };
3236
3237 let word_break_css = if dom_declared & DOM_HAS_WORD_BREAK != 0 {
3238 styled_dom
3239 .css_property_cache
3240 .ptr
3241 .get_word_break(node_data, &id, node_state)
3242 .and_then(|s| s.get_property().copied())
3243 .unwrap_or_default()
3244 } else {
3245 Default::default()
3246 };
3247
3248 let overflow_wrap_css = if dom_declared & DOM_HAS_OVERFLOW_WRAP != 0 {
3249 styled_dom
3250 .css_property_cache
3251 .ptr
3252 .get_overflow_wrap(node_data, &id, node_state)
3253 .and_then(|s| s.get_property().copied())
3254 .unwrap_or_default()
3255 } else {
3256 Default::default()
3257 };
3258
3259 let line_break_css = if dom_declared & DOM_HAS_LINE_BREAK != 0 {
3260 styled_dom
3261 .css_property_cache
3262 .ptr
3263 .get_line_break(node_data, &id, node_state)
3264 .and_then(|s| s.get_property().copied())
3265 .unwrap_or_default()
3266 } else {
3267 Default::default()
3268 };
3269
3270 let text_align_last_css = if dom_declared & DOM_HAS_TEXT_ALIGN_LAST != 0 {
3271 styled_dom
3272 .css_property_cache
3273 .ptr
3274 .get_text_align_last(node_data, &id, node_state)
3275 .and_then(|s| s.get_property().copied())
3276 .unwrap_or_default()
3277 } else {
3278 Default::default()
3279 };
3280
3281 let overflow_behaviour = get_overflow_x(styled_dom, id, node_state).unwrap_or_default();
3282
3283 // +spec:display-property:21f728 - vertical-align shorthand resolves inline-level box alignment
3284 // +spec:display-property:98fa8e - alignment-baseline values for inline-level boxes in IFC (implemented via vertical-align shorthand)
3285 // +spec:display-property:1f71ad - baseline-shift + alignment-baseline longhands mapped through vertical-align
3286 // +spec:display-property:89dd7b - line-relative shift values (top/center/bottom) and aligned subtree alignment
3287 // +spec:inline-formatting-context:21da06 - vertical-align uses line-over/line-under sides via writing_mode logical mapping
3288 // +spec:inline-formatting-context:295603 - baseline alignment: vertical-align determines how inline boxes align (baseline, super, sub, etc.)
3289 // +spec:inline-formatting-context:7351bf - default alignment baseline is alphabetic in horizontal typographic mode
3290 // +spec:inline-formatting-context:85de3d - vertical-align shorthand: alignment within line box
3291 // +spec:inline-formatting-context:aa8af0 - alignment baseline chosen by vertical-align, defaults to parent's dominant baseline
3292 // +spec:inline-formatting-context:e475d2 - baseline and vertical-align control transverse alignment of inline content on line boxes
3293 // +spec:overflow:d44eac - vertical-align inline box alignment (CSS 2.2 model covers baseline/top/middle/bottom/sub/super/text-top/text-bottom)
3294 // +spec:writing-modes:313575 - alignment-baseline: inline-level boxes align baselines within parent inline box's alignment context along inline axis
3295 // +spec:writing-modes:60ad67 - inline layout aligns boxes in block axis via baselines
3296 // +spec:writing-modes:0127e5 - line-relative directions: line-over/under map to vertical-align top/bottom
3297 // Get vertical-align from CSS property cache (defaults to Baseline per CSS spec)
3298 // +spec:inline-formatting-context:686f8b - vertical-align shorthand: alignment-baseline + baseline-shift for inline boxes
3299 // +spec:inline-formatting-context:e579b6 - vertical-align / baseline alignment in inline context
3300 // +spec:inline-formatting-context:a01a75 - dominant baseline alignment for atomic inlines
3301 let vertical_align = match get_vertical_align_property(styled_dom, id, node_state) {
3302 MultiValue::Exact(v) => v,
3303 _ => StyleVerticalAlign::default(),
3304 };
3305
3306 // +spec:display-property:c03a6b - baseline-shift (sub/super/length/percentage) and line-relative (top/center/bottom) shifts handled via vertical-align
3307 let vertical_align = match vertical_align {
3308 StyleVerticalAlign::Baseline => text3::cache::VerticalAlign::Baseline,
3309 StyleVerticalAlign::Top => text3::cache::VerticalAlign::Top,
3310 StyleVerticalAlign::Middle => text3::cache::VerticalAlign::Middle,
3311 StyleVerticalAlign::Bottom => text3::cache::VerticalAlign::Bottom,
3312 StyleVerticalAlign::Sub => text3::cache::VerticalAlign::Sub,
3313 // +spec:inline-formatting-context:fe563c - vertical-align: super shifts inline to superscript position
3314 // +spec:inline-formatting-context:fe563c - vertical-align:super shifts child to superscript position
3315 StyleVerticalAlign::Superscript => text3::cache::VerticalAlign::Super,
3316 StyleVerticalAlign::TextTop => text3::cache::VerticalAlign::TextTop,
3317 StyleVerticalAlign::TextBottom => text3::cache::VerticalAlign::TextBottom,
3318 // §10.8.1: <percentage> refers to line-height of the element itself
3319 StyleVerticalAlign::Percentage(p) => {
3320 let lh_n = line_height_value.inner.normalized();
3321 let resolved_lh = if lh_n < 0.0 { -lh_n } else { lh_n * font_size };
3322 let offset = p.normalized() * resolved_lh;
3323 text3::cache::VerticalAlign::Offset(offset)
3324 }
3325 // §10.8.1: <length> is absolute offset from baseline
3326 StyleVerticalAlign::Length(l) => {
3327 let offset = super::calc::resolve_pixel_value(&l, 0.0, font_size, font_size);
3328 text3::cache::VerticalAlign::Offset(offset)
3329 }
3330 };
3331 // +spec:block-formatting-context:987746 - text-orientation property (mixed/upright/sideways) for vertical writing modes
3332 // +spec:inline-formatting-context:cbe738 - text-orientation (mixed/upright/sideways) bi-orientational transform for vertical text
3333 // +spec:writing-modes:09a1bb - vertical typesetting orientation (upright/sideways) for vertical-rl/vertical-lr
3334 // +spec:writing-modes:2eb1b2 - text-orientation (mixed/upright/sideways) applied to vertical text layout
3335 let text_orientation = match get_text_orientation_property(styled_dom, id, node_state) {
3336 MultiValue::Exact(o) => match o {
3337 StyleTextOrientation::Mixed => text3::cache::TextOrientation::Mixed,
3338 StyleTextOrientation::Upright => text3::cache::TextOrientation::Upright,
3339 // +spec:block-formatting-context:a606e6 - sideways text typeset rotated 90° CW in vertical modes
3340 StyleTextOrientation::Sideways => text3::cache::TextOrientation::Sideways,
3341 },
3342 _ => text3::cache::TextOrientation::default(),
3343 };
3344
3345 // +spec:display-property:8364c0 - direction property (ltr/rtl) sets paragraph embedding level for bidi algorithm
3346 // +spec:text-alignment-spacing:97b93a - direction property affects text-align:justify last-line alignment
3347 // +spec:writing-modes:73aaff - block elements inherit base direction from parent via CSS direction property
3348 // +spec:writing-modes:8a888b - line box inline base direction from containing block's direction
3349 // Get the direction property from the CSS cache (defaults to LTR if not set)
3350 // +spec:display-property:da3b59 - direction property specifies inline base direction for ordering inline-level content
3351 // +spec:inline-formatting-context:97af40 - direction property sets inline base direction for bidi, text alignment, overflow
3352 // +spec:writing-modes:2deb38 - bidirectional reordering via CSS direction property
3353 // +spec:writing-modes:fbb332 - in vertical writing modes, text-orientation:upright forces used direction to ltr
3354 let direction = match constraints.writing_mode {
3355 LayoutWritingMode::VerticalRl | LayoutWritingMode::VerticalLr
3356 if matches!(text_orientation, text3::cache::TextOrientation::Upright) =>
3357 {
3358 Some(text3::cache::BidiDirection::Ltr)
3359 }
3360 _ => match get_direction_property(styled_dom, id, node_state) {
3361 MultiValue::Exact(d) => Some(match d {
3362 StyleDirection::Ltr => text3::cache::BidiDirection::Ltr,
3363 StyleDirection::Rtl => text3::cache::BidiDirection::Rtl,
3364 }),
3365 _ => None,
3366 },
3367 };
3368
3369 // Get unicode-bidi property for bidi algorithm configuration
3370 // +spec:containing-block:0d4914 - unicode-bidi: plaintext causes P2/P3 heuristics instead of HL1 override
3371 let unicode_bidi_val = if dom_declared & DOM_HAS_UNICODE_BIDI != 0 {
3372 match get_unicode_bidi_property(styled_dom, id, node_state) {
3373 MultiValue::Exact(u) => match u {
3374 StyleUnicodeBidi::Normal => text3::cache::UnicodeBidi::Normal,
3375 StyleUnicodeBidi::Embed => text3::cache::UnicodeBidi::Embed,
3376 StyleUnicodeBidi::Isolate => text3::cache::UnicodeBidi::Isolate,
3377 StyleUnicodeBidi::BidiOverride => text3::cache::UnicodeBidi::BidiOverride,
3378 StyleUnicodeBidi::IsolateOverride => text3::cache::UnicodeBidi::IsolateOverride,
3379 StyleUnicodeBidi::Plaintext => text3::cache::UnicodeBidi::Plaintext,
3380 },
3381 _ => text3::cache::UnicodeBidi::Normal,
3382 }
3383 } else {
3384 text3::cache::UnicodeBidi::Normal
3385 };
3386
3387 debug_info!(
3388 ctx,
3389 "dom_id={:?}, available_size={}x{}, setting available_width={}",
3390 dom_id,
3391 constraints.available_size.width,
3392 constraints.available_size.height,
3393 constraints.available_size.width
3394 );
3395
3396 // +spec:box-model:8113d7 - text-indent treated as margin on start edge of line box
3397 // +spec:display-contents:5f95ac - text-indent: percentage=0 for intrinsic sizing, each-line and hanging keywords
3398 // +spec:floats:17c74a - text-indent applied to first line (5em indentation with no floats)
3399 // +spec:positioning:1e32b1 - text-indent with hanging/each-line keywords resolved and passed to text layout
3400 let text_indent_prop = if dom_declared & DOM_HAS_TEXT_INDENT != 0 {
3401 styled_dom
3402 .css_property_cache
3403 .ptr
3404 .get_text_indent(node_data, &id, node_state)
3405 .and_then(|s| s.get_property().cloned())
3406 } else {
3407 None
3408 };
3409 let is_intrinsic_sizing = matches!(
3410 constraints.available_width_type,
3411 Text3AvailableSpace::MinContent | Text3AvailableSpace::MaxContent
3412 );
3413 // +spec:intrinsic-sizing:0e8625 - percentage text-indent treated as 0 for intrinsic size contributions
3414 let text_indent = text_indent_prop
3415 .map(|ti| {
3416 // CSS Text 3 §8.1: "Percentages must be treated as 0 for the purpose
3417 // of calculating intrinsic size contributions"
3418 if is_intrinsic_sizing && ti.inner.to_percent().is_some() {
3419 return 0.0;
3420 }
3421 let context = ResolutionContext {
3422 element_font_size: get_element_font_size(styled_dom, id, node_state),
3423 parent_font_size: get_parent_font_size(styled_dom, id, node_state),
3424 root_font_size: get_root_font_size(styled_dom, node_state),
3425 containing_block_size: PhysicalSize::new(constraints.available_size.width, 0.0),
3426 element_size: None,
3427 viewport_size: PhysicalSize::new(ctx.viewport_size.width, ctx.viewport_size.height),
3428 };
3429 ti.inner
3430 .resolve_with_context(&context, PropertyContext::Other)
3431 })
3432 .unwrap_or(0.0);
3433 let text_indent_each_line = text_indent_prop.map(|ti| ti.each_line).unwrap_or(false);
3434 let text_indent_hanging = text_indent_prop.map(|ti| ti.hanging).unwrap_or(false);
3435
3436 // ResolutionContext shared by column-gap and column-width (both resolve
3437 // lengths against the same font/viewport, with no containing-block size).
3438 let column_resolve_ctx = ResolutionContext {
3439 element_font_size: get_element_font_size(styled_dom, id, node_state),
3440 parent_font_size: get_parent_font_size(styled_dom, id, node_state),
3441 root_font_size: get_root_font_size(styled_dom, node_state),
3442 containing_block_size: PhysicalSize::new(0.0, 0.0),
3443 element_size: None,
3444 viewport_size: PhysicalSize::new(ctx.viewport_size.width, ctx.viewport_size.height),
3445 };
3446
3447 // Read a declared CSS property from the cache, returning None when the
3448 // DOM-level declared bit is clear (no node sets the property).
3449 macro_rules! declared_prop {
3450 ($bit:expr, $getter:ident) => {
3451 if dom_declared & $bit != 0 {
3452 styled_dom
3453 .css_property_cache
3454 .ptr
3455 .$getter(node_data, &id, node_state)
3456 .and_then(|s| s.get_property())
3457 } else {
3458 None
3459 }
3460 };
3461 }
3462
3463 // Get column-gap for multi-column layout (default: normal = 1em)
3464 let column_gap = declared_prop!(DOM_HAS_COLUMN_GAP, get_column_gap)
3465 .map(|cg| {
3466 cg.inner
3467 .resolve_with_context(&column_resolve_ctx, PropertyContext::Other)
3468 })
3469 .unwrap_or_else(|| get_element_font_size(styled_dom, id, node_state));
3470
3471 // Get column-width for multi-column layout (None = auto)
3472 let column_width =
3473 declared_prop!(DOM_HAS_COLUMN_WIDTH, get_column_width).and_then(|cw| match cw {
3474 ColumnWidth::Auto => None,
3475 ColumnWidth::Length(px) => {
3476 Some(px.resolve_with_context(&column_resolve_ctx, PropertyContext::Other))
3477 }
3478 });
3479
3480 // Get column-count for multi-column layout (default: 1 = no columns)
3481 let explicit_column_count =
3482 declared_prop!(DOM_HAS_COLUMN_COUNT, get_column_count).copied();
3483
3484 // CSS multi-column: derive column count from column-width when column-count is auto.
3485 // Per spec: N = max(1, floor((available-width + column-gap) / (column-width + column-gap)))
3486 let columns = match (explicit_column_count, column_width) {
3487 (Some(ColumnCount::Integer(n)), _) => n,
3488 (_, Some(cw)) if cw > 0.0 => {
3489 let avail = constraints.available_size.width;
3490 ((avail + column_gap) / (cw + column_gap)).floor().max(1.0) as u32
3491 }
3492 _ => 1,
3493 };
3494
3495 // +spec:line-breaking:b4928e - white-space values mapped to wrap/whitespace processing rules
3496 // Map white-space CSS property to TextWrap
3497 let resolved_ws = match get_white_space_property(styled_dom, id, node_state) {
3498 MultiValue::Exact(ws) => ws,
3499 _ => StyleWhiteSpace::Normal,
3500 };
3501 let text_wrap = match resolved_ws {
3502 StyleWhiteSpace::Normal => text3::cache::TextWrap::Wrap,
3503 StyleWhiteSpace::Nowrap => text3::cache::TextWrap::NoWrap,
3504 StyleWhiteSpace::Pre => text3::cache::TextWrap::NoWrap,
3505 StyleWhiteSpace::PreWrap => text3::cache::TextWrap::Wrap,
3506 StyleWhiteSpace::PreLine => text3::cache::TextWrap::Wrap,
3507 StyleWhiteSpace::BreakSpaces => text3::cache::TextWrap::Wrap,
3508 };
3509 let white_space_mode = match resolved_ws {
3510 StyleWhiteSpace::Normal => text3::cache::WhiteSpaceMode::Normal,
3511 StyleWhiteSpace::Nowrap => text3::cache::WhiteSpaceMode::Nowrap,
3512 StyleWhiteSpace::Pre => text3::cache::WhiteSpaceMode::Pre,
3513 StyleWhiteSpace::PreWrap => text3::cache::WhiteSpaceMode::PreWrap,
3514 StyleWhiteSpace::PreLine => text3::cache::WhiteSpaceMode::PreLine,
3515 StyleWhiteSpace::BreakSpaces => text3::cache::WhiteSpaceMode::BreakSpaces,
3516 };
3517
3518 // +spec:block-formatting-context:fd60a8 - initial letter box is in-flow in its BFC, originating line box
3519 // +spec:block-formatting-context:c5ba02 - initial letter inline flow layout (alignment, white space collapsing)
3520 // +spec:block-formatting-context:83f8a7 - initial letter wrapping modes (none, all, first)
3521 // +spec:block-formatting-context:fef28d - initial letter box is in-flow in its BFC, part of originating line box
3522 // +spec:box-model:c3ce58 - initial letter block-start margin edge must be below containing block content edge
3523 // +spec:display-contents:568fe2 - initial letter participates in same IFC as its line
3524 // +spec:display-property:a89adb - initial letter boxes from non-replaced inline boxes and atomic inlines
3525 // +spec:display-property:4b59ce - initial-letter applies to inline-level boxes at start of first line
3526 // +spec:display-property:756cad - initial-letter sizing: drop/raise/sunken initial computation
3527 // +spec:display-property:8b08f4 - initial-letter applied to first inline-level child of block container
3528 // +spec:display-property:8c1dce - initial-letter property: size/sink for drop caps on inline-level boxes
3529 // +spec:display-property:b453a3 - initial-letter applies to inline-level boxes in IFC
3530 // +spec:display-property:b5e149 - initial letters are in-flow inline-level content, not floats
3531 // +spec:display-property:fa044e - initial-letter applies to first-child inline-level boxes
3532 // +spec:line-height:306d87 - initial-letter sizing must use containing block's line-height, not spanned lines' heights
3533 // +spec:writing-modes:903310 - atomic initial letters use normal sizing; only positioning is special
3534 // Get initial-letter for drop caps
3535 // +spec:display-property:4c69bf - read initial-letter-align for alignment points
3536 let initial_letter_align = if dom_declared & DOM_HAS_INITIAL_LETTER_ALIGN != 0 {
3537 styled_dom
3538 .css_property_cache
3539 .ptr
3540 .get_initial_letter_align(node_data, &id, node_state)
3541 .and_then(|s| s.get_property())
3542 .map(|a| match a {
3543 azul_css::props::style::text::StyleInitialLetterAlign::Auto => text3::cache::InitialLetterAlign::Auto,
3544 azul_css::props::style::text::StyleInitialLetterAlign::Alphabetic => text3::cache::InitialLetterAlign::Alphabetic,
3545 azul_css::props::style::text::StyleInitialLetterAlign::Hanging => text3::cache::InitialLetterAlign::Hanging,
3546 azul_css::props::style::text::StyleInitialLetterAlign::Ideographic => text3::cache::InitialLetterAlign::Ideographic,
3547 })
3548 .unwrap_or(text3::cache::InitialLetterAlign::Auto)
3549 } else {
3550 text3::cache::InitialLetterAlign::Auto
3551 };
3552 // +spec:display-property:5af252 - initial-letter on inline-level box not at line start uses normal
3553 // +spec:text-alignment-spacing:a17609 - sunken initial letters suppress letter-spacing and justification (not word-spacing) with adjacent content
3554 // +spec:display-property:68ab22 - initial-letter only applies in IFC (inline-level);
3555 // float!=none or position!=static causes display to compute to block (BFC), so
3556 // initial-letter naturally does not apply to those elements
3557 // +spec:writing-modes:c89d19 - initial-letter block-axis positioning: sink determines block offset
3558 // +spec:display-property:b67500 - initial-letter size/sink: values other than normal make box an initial letter box (inline-level, in-flow)
3559 // +spec:display-property:416f27 - initial-letter sink defaults to "drop" (sink = size floored) when omitted
3560 let initial_letter = if dom_declared & DOM_HAS_INITIAL_LETTER != 0 {
3561 styled_dom
3562 .css_property_cache
3563 .ptr
3564 .get_initial_letter(node_data, &id, node_state)
3565 .and_then(|s| s.get_property())
3566 .map(|il| {
3567 use std::num::NonZeroUsize;
3568 let sink = match il.sink {
3569 azul_css::corety::OptionU32::Some(s) => s,
3570 azul_css::corety::OptionU32::None => il.size, // "drop" assumed: sink = size
3571 };
3572 text3::cache::InitialLetter {
3573 size: il.size as f32,
3574 sink,
3575 count: NonZeroUsize::new(1).unwrap(),
3576 align: initial_letter_align,
3577 }
3578 })
3579 } else {
3580 None
3581 };
3582
3583 // If initial-letter is set, compute the drop cap exclusion area and add it
3584 // to the shape exclusions so that text wraps around the enlarged letter.
3585 // +spec:box-model:d4adf6 - ancestor inline boundaries excluded via geometric exclusion
3586 // +spec:floats:c5e23f - floats in subsequent lines adjacent to a sunk initial letter must clear it
3587 if let Some(ref il) = initial_letter {
3588 let lh_n = line_height_value.inner.normalized();
3589 let computed_line_height = if lh_n < 0.0 { -lh_n } else { lh_n * font_size };
3590 let (letter_w, letter_h) = layout_initial_letter(
3591 il.size,
3592 il.sink,
3593 constraints.available_size.width,
3594 computed_line_height,
3595 );
3596 if letter_w > 0.0 && letter_h > 0.0 {
3597 // Place the exclusion at the inline-start (x=0, y=0 relative to the IFC).
3598 // This creates a rectangular exclusion that text flows around.
3599 shape_exclusions.push(ShapeBoundary::Rectangle(crate::text3::cache::Rect {
3600 x: 0.0,
3601 y: 0.0,
3602 width: letter_w,
3603 height: letter_h,
3604 }));
3605 }
3606 }
3607
3608 // Get line-clamp for limiting visible lines
3609 let line_clamp = if dom_declared & DOM_HAS_LINE_CLAMP != 0 {
3610 styled_dom
3611 .css_property_cache
3612 .ptr
3613 .get_line_clamp(node_data, &id, node_state)
3614 .and_then(|s| s.get_property())
3615 .and_then(|lc| std::num::NonZeroUsize::new(lc.max_lines))
3616 } else {
3617 None
3618 };
3619
3620 // Get hanging-punctuation for hanging punctuation marks
3621 let hanging_punctuation = if dom_declared & DOM_HAS_HANGING_PUNCTUATION != 0 {
3622 styled_dom
3623 .css_property_cache
3624 .ptr
3625 .get_hanging_punctuation(node_data, &id, node_state)
3626 .and_then(|s| s.get_property())
3627 .map(|hp| hp.is_enabled())
3628 .unwrap_or(false)
3629 } else {
3630 false
3631 };
3632
3633 // Get text-combine-upright for vertical text combination
3634 // +spec:line-breaking:9f150a - text-combine-upright:all composes glyphs horizontally, ignoring letter-spacing and forced line breaks
3635 // +spec:line-breaking:1b88cd - text-combine-upright:all layout: inline-block with 1em square, ignoring forced line breaks
3636 // +spec:inline-formatting-context:c8d8d9 - text-combine-upright compression passed to text shaping engine
3637 // +spec:inline-formatting-context:f4ef7d - text-combine-upright layout rules (1em square composition)
3638 let text_combine_upright = if dom_declared & DOM_HAS_TEXT_COMBINE_UPRIGHT != 0 {
3639 styled_dom
3640 .css_property_cache
3641 .ptr
3642 .get_text_combine_upright(node_data, &id, node_state)
3643 .and_then(|s| s.get_property())
3644 // +spec:display-property:6f174d - text-combine-upright horizontal-in-vertical composition
3645 .map(|tcu| match tcu {
3646 StyleTextCombineUpright::None => text3::cache::TextCombineUpright::None,
3647 StyleTextCombineUpright::All => text3::cache::TextCombineUpright::All,
3648 StyleTextCombineUpright::Digits(n) => text3::cache::TextCombineUpright::Digits(*n),
3649 })
3650 } else {
3651 None
3652 };
3653
3654 // Get exclusion-margin (CSS Exclusions L1) and shape-margin (CSS Shapes L1)
3655 // for shape exclusions. We sum both into a single margin knob — strictly,
3656 // they apply to different sources (exclusion-margin → CSS Exclusions,
3657 // shape-margin → shape-outside), but the layout solver currently keeps
3658 // a single per-IFC margin value, so the two get added.
3659 let exclusion_margin_base = if dom_declared & DOM_HAS_EXCLUSION_MARGIN != 0 {
3660 styled_dom
3661 .css_property_cache
3662 .ptr
3663 .get_exclusion_margin(node_data, &id, node_state)
3664 .and_then(|s| s.get_property())
3665 .map(|em| em.inner.get() as f32)
3666 .unwrap_or(0.0)
3667 } else {
3668 0.0
3669 };
3670
3671 let shape_margin = if dom_declared & DOM_HAS_SHAPE_MARGIN != 0 {
3672 styled_dom
3673 .css_property_cache
3674 .ptr
3675 .get_shape_margin(node_data, &id, node_state)
3676 .and_then(|s| s.get_property())
3677 .map(|sm| sm.inner.number.get() as f32)
3678 .unwrap_or(0.0)
3679 } else {
3680 0.0
3681 };
3682
3683 let exclusion_margin = exclusion_margin_base + shape_margin;
3684
3685 // Get hyphenation-language for language-specific hyphenation
3686 let hyphenation_language = if dom_declared & DOM_HAS_HYPHENATION_LANGUAGE != 0 {
3687 styled_dom
3688 .css_property_cache
3689 .ptr
3690 .get_hyphenation_language(node_data, &id, node_state)
3691 .and_then(|s| s.get_property())
3692 .and_then(|hl| {
3693 #[cfg(feature = "text_layout_hyphenation")]
3694 {
3695 use hyphenation::{Language, Load};
3696 // Parse BCP 47 language code to hyphenation::Language
3697 match hl.inner.as_str() {
3698 "en-US" | "en" => Some(Language::EnglishUS),
3699 "de-DE" | "de" => Some(Language::German1996),
3700 "fr-FR" | "fr" => Some(Language::French),
3701 "es-ES" | "es" => Some(Language::Spanish),
3702 "it-IT" | "it" => Some(Language::Italian),
3703 "pt-PT" | "pt" => Some(Language::Portuguese),
3704 "nl-NL" | "nl" => Some(Language::Dutch),
3705 "pl-PL" | "pl" => Some(Language::Polish),
3706 "ru-RU" | "ru" => Some(Language::Russian),
3707 "zh-CN" | "zh" => Some(Language::Chinese),
3708 _ => None, // Unsupported language
3709 }
3710 }
3711 #[cfg(not(feature = "text_layout_hyphenation"))]
3712 {
3713 None::<crate::text3::script::Language>
3714 }
3715 })
3716 } else {
3717 None
3718 };
3719
3720 UnifiedConstraints {
3721 exclusion_margin,
3722 hyphenation_language,
3723 text_indent,
3724 text_indent_each_line,
3725 text_indent_hanging,
3726 initial_letter,
3727 line_clamp,
3728 columns,
3729 column_gap,
3730 hanging_punctuation,
3731 text_wrap,
3732 white_space_mode,
3733 text_combine_upright,
3734 segment_alignment: SegmentAlignment::Total,
3735 overflow: match overflow_behaviour {
3736 LayoutOverflow::Visible => text3::cache::OverflowBehavior::Visible,
3737 LayoutOverflow::Hidden | LayoutOverflow::Clip => text3::cache::OverflowBehavior::Hidden,
3738 LayoutOverflow::Scroll => text3::cache::OverflowBehavior::Scroll,
3739 LayoutOverflow::Auto => text3::cache::OverflowBehavior::Auto,
3740 },
3741 // Use the semantic available_width_type directly instead of converting from float.
3742 // This preserves MinContent/MaxContent semantics for intrinsic sizing.
3743 available_width: constraints.available_width_type,
3744 // For scrollable containers (overflow: scroll/auto), don't constrain height
3745 // so that the full content is laid out and content_size is calculated correctly.
3746 available_height: match overflow_behaviour {
3747 LayoutOverflow::Scroll | LayoutOverflow::Auto => None,
3748 _ => Some(constraints.available_size.height),
3749 },
3750 shape_boundaries, // CSS shape-inside: text flows within shape
3751 shape_exclusions, // CSS shape-outside + floats: text wraps around shapes
3752 writing_mode: Some(match writing_mode {
3753 LayoutWritingMode::HorizontalTb => text3::cache::WritingMode::HorizontalTb,
3754 LayoutWritingMode::VerticalRl => text3::cache::WritingMode::VerticalRl,
3755 LayoutWritingMode::VerticalLr => text3::cache::WritingMode::VerticalLr,
3756 }),
3757 direction, // Use the CSS direction property (currently defaulting to LTR)
3758 unicode_bidi: unicode_bidi_val,
3759 // +spec:overflow:7ff7d1 - hyphens property: none/manual/auto hyphenation control
3760 hyphenation: match hyphenation {
3761 StyleHyphens::None => text3::cache::Hyphens::None,
3762 StyleHyphens::Manual => text3::cache::Hyphens::Manual,
3763 StyleHyphens::Auto => text3::cache::Hyphens::Auto,
3764 },
3765 text_orientation,
3766 // +spec:text-alignment-spacing:6cb965 - text-align shorthand sets text-align-all (mapped here from computed value)
3767 // +spec:text-alignment-spacing:838967 - map text-align values (start/end/left/right/center/justify) to inline alignment
3768 // +spec:text-alignment-spacing:d9ea45 - property index: text-align, text-justify, letter-spacing mapped to layout
3769 // +spec:text-alignment-spacing:600fda - text-align values (left/right/center/justify) mapped per CSS Text §6.1
3770 text_align: match text_align {
3771 StyleTextAlign::Start => text3::cache::TextAlign::Start,
3772 StyleTextAlign::End => text3::cache::TextAlign::End,
3773 StyleTextAlign::Left => text3::cache::TextAlign::Left,
3774 StyleTextAlign::Right => text3::cache::TextAlign::Right,
3775 StyleTextAlign::Center => text3::cache::TextAlign::Center,
3776 StyleTextAlign::Justify => text3::cache::TextAlign::Justify,
3777 },
3778 // +spec:text-alignment-spacing:0ea31d - text-justify inter-word/inter-character/distribute mapped per §6.4
3779 // +spec:text-alignment-spacing:01244f - text-justify: none disables justification, auto uses inter-word as universal default
3780 text_justify: match text_justify {
3781 LayoutTextJustify::None => text3::cache::JustifyContent::None,
3782 LayoutTextJustify::Auto => text3::cache::JustifyContent::InterWord,
3783 LayoutTextJustify::InterWord => text3::cache::JustifyContent::InterWord,
3784 LayoutTextJustify::InterCharacter => text3::cache::JustifyContent::InterCharacter,
3785 LayoutTextJustify::Distribute => text3::cache::JustifyContent::InterCharacter, // distribute computes to inter-character
3786 },
3787 // +spec:line-height:79f3aa - line-height resolved: normal defaults to 1.2, <number>/<percentage> × font-size
3788 // Negative normalized() = absolute px value (convention from parser for "50px" etc.)
3789 line_height: text3::cache::LineHeight::Px({
3790 let n = line_height_value.inner.normalized();
3791 if n < 0.0 { -n } else { n * font_size }
3792 }),
3793 // container's first available font. Approximated as 80%/20% of font_size (typical
3794 // for Latin fonts). TODO: resolve actual font and use its OS/2 metrics.
3795 strut_ascent: font_size * 0.8,
3796 strut_descent: font_size * 0.2,
3797 strut_x_height: font_size * 0.5, // 0.5em fallback per CSS Inline 3 Appendix A
3798 // ch unit width: try to get actual space width from font, fall back to 0.5 * font_size
3799 ch_width: font_size * 0.5, // TODO: resolve from ParsedFontTrait::get_space_width()
3800 vertical_align,
3801 // +spec:inline-formatting-context:48ce44 - overflow-wrap property: break at otherwise disallowed points to prevent overflow
3802 // +spec:line-breaking:bbb5f7 - overflow-wrap: anywhere vs break-word distinction for min-content
3803 overflow_wrap: if word_break_css == StyleWordBreak::BreakWord {
3804 // +spec:line-breaking:815882 - break-word forces overflow-wrap: anywhere
3805 text3::cache::OverflowWrap::Anywhere
3806 } else {
3807 match overflow_wrap_css {
3808 StyleOverflowWrap::Normal => text3::cache::OverflowWrap::Normal,
3809 StyleOverflowWrap::Anywhere => text3::cache::OverflowWrap::Anywhere,
3810 StyleOverflowWrap::BreakWord => text3::cache::OverflowWrap::BreakWord,
3811 }
3812 },
3813 text_align_last: match text_align_last_css {
3814 StyleTextAlignLast::Auto => text3::cache::TextAlign::default(),
3815 StyleTextAlignLast::Start => text3::cache::TextAlign::Start,
3816 StyleTextAlignLast::End => text3::cache::TextAlign::End,
3817 StyleTextAlignLast::Left => text3::cache::TextAlign::Left,
3818 StyleTextAlignLast::Right => text3::cache::TextAlign::Right,
3819 StyleTextAlignLast::Center => text3::cache::TextAlign::Center,
3820 StyleTextAlignLast::Justify => text3::cache::TextAlign::Justify,
3821 },
3822 // +spec:line-breaking:815882 - word-break: break-word => normal + overflow-wrap: anywhere
3823 word_break: match word_break_css {
3824 StyleWordBreak::Normal | StyleWordBreak::BreakWord => text3::cache::WordBreak::Normal,
3825 StyleWordBreak::BreakAll => text3::cache::WordBreak::BreakAll,
3826 StyleWordBreak::KeepAll => text3::cache::WordBreak::KeepAll,
3827 },
3828 // +spec:white-space-processing:bc5f7b - line-break with break-spaces allows breaking before first space
3829 // CSS Text Level 3 §5.3: The line-break property affects preserved white space behavior:
3830 // - normal/pre-line: preserved white space at end/start of line is discarded
3831 // - nowrap/pre: wrapping is forbidden altogether
3832 // - pre-wrap: preserved white space hangs
3833 // - break-spaces: allows breaking before first space of a sequence
3834 // break-spaces allows wrapping preserved spaces to next line; for other white-space values,
3835 // preserved spaces at line ends are either discarded (normal, pre-line), wrapping is
3836 // forbidden (nowrap, pre), or they hang (pre-wrap).
3837 line_break: match line_break_css {
3838 StyleLineBreak::Auto => text3::cache::LineBreakStrictness::Auto,
3839 StyleLineBreak::Loose => text3::cache::LineBreakStrictness::Loose,
3840 StyleLineBreak::Normal => text3::cache::LineBreakStrictness::Normal,
3841 StyleLineBreak::Strict => text3::cache::LineBreakStrictness::Strict,
3842 StyleLineBreak::Anywhere => text3::cache::LineBreakStrictness::Anywhere,
3843 },
3844 }
3845}
3846
3847// Table Formatting Context (CSS 2.2 § 17)
3848// +spec:display-property:d887c0 - Table wrapper box BFC, caption-side, table grid layout (§17.4-17.5)
3849// +spec:positioning:930891 - Table formatting context implementation (CSS 2.2 § 17 introduction)
3850
3851// +spec:inline-formatting-context:9c272d - CSS table model: row-primary structure, display-to-table-element mapping, visual formatting as rectangular grid
3852/// Lays out a Table Formatting Context.
3853/// Table column information for layout calculations
3854#[derive(Debug, Clone)]
3855pub struct TableColumnInfo {
3856 /// Minimum width required for this column
3857 pub min_width: f32,
3858 /// Maximum width desired for this column
3859 pub max_width: f32,
3860 /// Computed final width for this column
3861 pub computed_width: Option<f32>,
3862}
3863
3864/// Information about a table cell for layout
3865#[derive(Debug, Clone)]
3866pub struct TableCellInfo {
3867 /// Node index in the layout tree
3868 pub node_index: usize,
3869 /// Column index (0-based)
3870 pub column: usize,
3871 /// Number of columns this cell spans
3872 pub colspan: usize,
3873 /// Row index (0-based)
3874 pub row: usize,
3875 /// Number of rows this cell spans
3876 pub rowspan: usize,
3877}
3878
3879/// Table layout context - holds all information needed for table layout
3880#[derive(Debug)]
3881struct TableLayoutContext {
3882 /// Information about each column
3883 columns: Vec<TableColumnInfo>,
3884 /// Information about each cell
3885 cells: Vec<TableCellInfo>,
3886 /// Number of rows in the table
3887 num_rows: usize,
3888 /// Whether to use fixed or auto layout algorithm
3889 use_fixed_layout: bool,
3890 /// Computed height for each row
3891 row_heights: Vec<f32>,
3892 /// Computed baseline offset for each row (distance from row top to row baseline)
3893 row_baselines: Vec<f32>,
3894 // +spec:inline-formatting-context:440ca9 - border-collapse/border-spacing/visibility:collapse table properties (CSS 2.2 §17.5-17.6)
3895 /// Border collapse mode
3896 border_collapse: StyleBorderCollapse,
3897 /// Border spacing (only used when border_collapse is Separate)
3898 border_spacing: LayoutBorderSpacing,
3899 /// CSS 2.2 Section 17.4: Index of table-caption child, if any
3900 caption_index: Option<usize>,
3901 // from display without forcing table re-layout
3902 /// CSS 2.2 Section 17.6: Rows with visibility:collapse (dynamic effects)
3903 /// Set of row indices that have visibility:collapse
3904 collapsed_rows: std::collections::HashSet<usize>,
3905 /// CSS 2.2 Section 17.6: Columns with visibility:collapse (dynamic effects)
3906 /// Set of column indices that have visibility:collapse
3907 collapsed_columns: std::collections::HashSet<usize>,
3908 /// Rows that are hidden-empty (zero height, border-spacing on only one side)
3909 hidden_empty_rows: std::collections::HashSet<usize>,
3910 /// Layout tree indices for each row (row index → layout node index)
3911 row_node_indices: Vec<usize>,
3912}
3913
3914impl TableLayoutContext {
3915 fn new() -> Self {
3916 Self {
3917 columns: Vec::new(),
3918 cells: Vec::new(),
3919 num_rows: 0,
3920 use_fixed_layout: false,
3921 row_heights: Vec::new(),
3922 row_baselines: Vec::new(),
3923 border_collapse: StyleBorderCollapse::Separate,
3924 border_spacing: LayoutBorderSpacing::default(),
3925 caption_index: None,
3926 collapsed_rows: std::collections::HashSet::new(),
3927 collapsed_columns: std::collections::HashSet::new(),
3928 hidden_empty_rows: std::collections::HashSet::new(),
3929 row_node_indices: Vec::new(),
3930 }
3931 }
3932}
3933
3934// +spec:table-layout:485791 - Six superimposed table layers: table, column-group, column, row-group, row, cell (bottom to top)
3935// +spec:table-layout:dcdf1b - Collapsing border model: border conflict resolution uses layer priority (cell > row > row-group > column > column-group > table)
3936/// Source of a border in the border conflict resolution algorithm
3937#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
3938pub enum BorderSource {
3939 Table = 0,
3940 ColumnGroup = 1,
3941 Column = 2,
3942 RowGroup = 3,
3943 Row = 4,
3944 Cell = 5,
3945}
3946
3947/// Information about a border for conflict resolution
3948#[derive(Debug, Clone)]
3949pub struct BorderInfo {
3950 pub width: f32,
3951 pub style: BorderStyle,
3952 pub color: ColorU,
3953 pub source: BorderSource,
3954}
3955
3956impl BorderInfo {
3957 pub fn new(width: f32, style: BorderStyle, color: ColorU, source: BorderSource) -> Self {
3958 Self {
3959 width,
3960 style,
3961 color,
3962 source,
3963 }
3964 }
3965
3966 // +spec:block-formatting-context:f772ae - border style priority for table border conflict resolution
3967 /// Get the priority of a border style for conflict resolution
3968 /// Higher number = higher priority
3969 pub fn style_priority(style: &BorderStyle) -> u8 {
3970 match style {
3971 BorderStyle::Hidden => 255, // Highest - suppresses all borders
3972 BorderStyle::None => 0, // Lowest - loses to everything
3973 BorderStyle::Double => 8,
3974 BorderStyle::Solid => 7,
3975 BorderStyle::Dashed => 6,
3976 BorderStyle::Dotted => 5,
3977 BorderStyle::Ridge => 4,
3978 BorderStyle::Outset => 3,
3979 BorderStyle::Groove => 2,
3980 BorderStyle::Inset => 1,
3981 }
3982 }
3983
3984 // +spec:box-model:2255c2 - Collapsing border conflict resolution (hidden wins, then none loses, then wider wins, then style priority)
3985 // +spec:box-model:b42c79 - border conflict resolution: hidden wins, then wider, then style priority, then source
3986 // +spec:box-model:503e9e - border conflict resolution: hidden wins, then wider, then style priority, then source priority
3987 // +spec:box-model:7eb217 - Border conflict resolution: hidden > none < wider > style priority > source priority > left/top
3988 // +spec:overflow:1fb482 - Border conflict resolution per CSS 2.2 §17.6.2.1 (hidden wins, then wider, then style priority, then source priority)
3989 // +spec:table-layout:882560 - Border conflict resolution (17.6.2.1): hidden wins, none loses, wider wins, style priority, source priority
3990 /// Compare two borders for conflict resolution per CSS 2.2 Section 17.6.2.1
3991 /// Returns the winning border
3992 // +spec:table-layout:21053b - border conflict resolution: hidden suppresses all, style priorities
3993 // +spec:table-layout:076617 - border conflict resolution algorithm and border style semantics in collapsing model
3994 pub fn resolve_conflict(a: &BorderInfo, b: &BorderInfo) -> Option<BorderInfo> {
3995 // 1. 'hidden' wins and suppresses all borders
3996 if a.style == BorderStyle::Hidden || b.style == BorderStyle::Hidden {
3997 return None;
3998 }
3999
4000 // 2. Filter out 'none' - if both are none, no border
4001 let a_is_none = a.style == BorderStyle::None;
4002 let b_is_none = b.style == BorderStyle::None;
4003
4004 if a_is_none && b_is_none {
4005 return None;
4006 }
4007 if a_is_none {
4008 return Some(b.clone());
4009 }
4010 if b_is_none {
4011 return Some(a.clone());
4012 }
4013
4014 // 3. Wider border wins
4015 if a.width > b.width {
4016 return Some(a.clone());
4017 }
4018 if b.width > a.width {
4019 return Some(b.clone());
4020 }
4021
4022 // 4. If same width, compare style priority
4023 let a_priority = Self::style_priority(&a.style);
4024 let b_priority = Self::style_priority(&b.style);
4025
4026 if a_priority > b_priority {
4027 return Some(a.clone());
4028 }
4029 if b_priority > a_priority {
4030 return Some(b.clone());
4031 }
4032
4033 // 5. If same style, source priority:
4034 // Cell > Row > RowGroup > Column > ColumnGroup > Table
4035 if a.source > b.source {
4036 return Some(a.clone());
4037 }
4038 if b.source > a.source {
4039 return Some(b.clone());
4040 }
4041
4042 // 6. Same priority - prefer first one (left/top in LTR)
4043 Some(a.clone())
4044 }
4045}
4046
4047/// Get border information for a node
4048fn get_border_info<T: ParsedFontTrait>(
4049 ctx: &LayoutContext<'_, T>,
4050 node: &LayoutNodeHot,
4051 source: BorderSource,
4052) -> (BorderInfo, BorderInfo, BorderInfo, BorderInfo) {
4053 use azul_css::props::{
4054 basic::{
4055 pixel::{PhysicalSize, PropertyContext, ResolutionContext},
4056 ColorU,
4057 },
4058 style::BorderStyle,
4059 };
4060 use get_element_font_size;
4061 use get_parent_font_size;
4062 use get_root_font_size;
4063
4064 let default_border = BorderInfo::new(
4065 0.0,
4066 BorderStyle::None,
4067 ColorU {
4068 r: 0,
4069 g: 0,
4070 b: 0,
4071 a: 0,
4072 },
4073 source,
4074 );
4075
4076 let Some(dom_id) = node.dom_node_id else {
4077 return (
4078 default_border.clone(),
4079 default_border.clone(),
4080 default_border.clone(),
4081 default_border.clone(),
4082 );
4083 };
4084
4085 let node_data = &ctx.styled_dom.node_data.as_container()[dom_id];
4086 let node_state = ctx.styled_dom.styled_nodes.as_container()[dom_id].styled_node_state.clone();
4087 let cache = &ctx.styled_dom.css_property_cache.ptr;
4088
4089 // FAST PATH: compact cache for normal state
4090 if let Some(ref cc) = cache.compact_cache {
4091 let idx = dom_id.index();
4092
4093 // Border styles from packed u16
4094 let bts = cc.get_border_top_style(idx);
4095 let brs = cc.get_border_right_style(idx);
4096 let bbs = cc.get_border_bottom_style(idx);
4097 let bls = cc.get_border_left_style(idx);
4098
4099 // Border colors from u32 RGBA
4100 let make_color = |raw: u32| -> ColorU {
4101 if raw == 0 {
4102 ColorU { r: 0, g: 0, b: 0, a: 0 }
4103 } else {
4104 ColorU {
4105 r: ((raw >> 24) & 0xFF) as u8,
4106 g: ((raw >> 16) & 0xFF) as u8,
4107 b: ((raw >> 8) & 0xFF) as u8,
4108 a: (raw & 0xFF) as u8,
4109 }
4110 }
4111 };
4112
4113 let btc = make_color(cc.get_border_top_color_raw(idx));
4114 let brc = make_color(cc.get_border_right_color_raw(idx));
4115 let bbc = make_color(cc.get_border_bottom_color_raw(idx));
4116 let blc = make_color(cc.get_border_left_color_raw(idx));
4117
4118 // Border widths from i16 × 10
4119 let decode_width = |raw: i16| -> f32 {
4120 if raw >= azul_css::compact_cache::I16_SENTINEL_THRESHOLD {
4121 0.0 // sentinel → fall back to 0
4122 } else {
4123 raw as f32 / 10.0
4124 }
4125 };
4126
4127 let btw = decode_width(cc.get_border_top_width_raw(idx));
4128 let brw = decode_width(cc.get_border_right_width_raw(idx));
4129 let bbw = decode_width(cc.get_border_bottom_width_raw(idx));
4130 let blw = decode_width(cc.get_border_left_width_raw(idx));
4131
4132 let top = if bts == BorderStyle::None { default_border.clone() }
4133 else { BorderInfo::new(btw, bts, btc, source) };
4134 let right = if brs == BorderStyle::None { default_border.clone() }
4135 else { BorderInfo::new(brw, brs, brc, source) };
4136 let bottom = if bbs == BorderStyle::None { default_border.clone() }
4137 else { BorderInfo::new(bbw, bbs, bbc, source) };
4138 let left = if bls == BorderStyle::None { default_border.clone() }
4139 else { BorderInfo::new(blw, bls, blc, source) };
4140
4141 return (top, right, bottom, left);
4142 }
4143
4144 // SLOW PATH: full cascade resolution
4145 let cache = &ctx.styled_dom.css_property_cache.ptr;
4146
4147 // Create resolution context for border-width (em/rem support, no % support)
4148 let element_font_size = get_element_font_size(ctx.styled_dom, dom_id, &node_state);
4149 let parent_font_size = get_parent_font_size(ctx.styled_dom, dom_id, &node_state);
4150 let root_font_size = get_root_font_size(ctx.styled_dom, &node_state);
4151
4152 let resolution_context = ResolutionContext {
4153 element_font_size,
4154 parent_font_size,
4155 root_font_size,
4156 // Not used for border-width
4157 containing_block_size: PhysicalSize::new(0.0, 0.0),
4158 // Not used for border-width
4159 element_size: None,
4160 viewport_size: PhysicalSize::new(ctx.viewport_size.width, ctx.viewport_size.height),
4161 };
4162
4163 // Top border
4164 let top = cache
4165 .get_border_top_style(node_data, &dom_id, &node_state)
4166 .and_then(|s| s.get_property())
4167 .map(|style_val| {
4168 let width = cache
4169 .get_border_top_width(node_data, &dom_id, &node_state)
4170 .and_then(|w| w.get_property())
4171 .map(|w| {
4172 w.inner
4173 .resolve_with_context(&resolution_context, PropertyContext::BorderWidth)
4174 })
4175 .unwrap_or(0.0);
4176 let color = cache
4177 .get_border_top_color(node_data, &dom_id, &node_state)
4178 .and_then(|c| c.get_property())
4179 .map(|c| c.inner)
4180 .unwrap_or(ColorU {
4181 r: 0,
4182 g: 0,
4183 b: 0,
4184 a: 255,
4185 });
4186 BorderInfo::new(width, style_val.inner, color, source)
4187 })
4188 .unwrap_or_else(|| default_border.clone());
4189
4190 // Right border
4191 let right = cache
4192 .get_border_right_style(node_data, &dom_id, &node_state)
4193 .and_then(|s| s.get_property())
4194 .map(|style_val| {
4195 let width = cache
4196 .get_border_right_width(node_data, &dom_id, &node_state)
4197 .and_then(|w| w.get_property())
4198 .map(|w| {
4199 w.inner
4200 .resolve_with_context(&resolution_context, PropertyContext::BorderWidth)
4201 })
4202 .unwrap_or(0.0);
4203 let color = cache
4204 .get_border_right_color(node_data, &dom_id, &node_state)
4205 .and_then(|c| c.get_property())
4206 .map(|c| c.inner)
4207 .unwrap_or(ColorU {
4208 r: 0,
4209 g: 0,
4210 b: 0,
4211 a: 255,
4212 });
4213 BorderInfo::new(width, style_val.inner, color, source)
4214 })
4215 .unwrap_or_else(|| default_border.clone());
4216
4217 // Bottom border
4218 let bottom = cache
4219 .get_border_bottom_style(node_data, &dom_id, &node_state)
4220 .and_then(|s| s.get_property())
4221 .map(|style_val| {
4222 let width = cache
4223 .get_border_bottom_width(node_data, &dom_id, &node_state)
4224 .and_then(|w| w.get_property())
4225 .map(|w| {
4226 w.inner
4227 .resolve_with_context(&resolution_context, PropertyContext::BorderWidth)
4228 })
4229 .unwrap_or(0.0);
4230 let color = cache
4231 .get_border_bottom_color(node_data, &dom_id, &node_state)
4232 .and_then(|c| c.get_property())
4233 .map(|c| c.inner)
4234 .unwrap_or(ColorU {
4235 r: 0,
4236 g: 0,
4237 b: 0,
4238 a: 255,
4239 });
4240 BorderInfo::new(width, style_val.inner, color, source)
4241 })
4242 .unwrap_or_else(|| default_border.clone());
4243
4244 // Left border
4245 let left = cache
4246 .get_border_left_style(node_data, &dom_id, &node_state)
4247 .and_then(|s| s.get_property())
4248 .map(|style_val| {
4249 let width = cache
4250 .get_border_left_width(node_data, &dom_id, &node_state)
4251 .and_then(|w| w.get_property())
4252 .map(|w| {
4253 w.inner
4254 .resolve_with_context(&resolution_context, PropertyContext::BorderWidth)
4255 })
4256 .unwrap_or(0.0);
4257 let color = cache
4258 .get_border_left_color(node_data, &dom_id, &node_state)
4259 .and_then(|c| c.get_property())
4260 .map(|c| c.inner)
4261 .unwrap_or(ColorU {
4262 r: 0,
4263 g: 0,
4264 b: 0,
4265 a: 255,
4266 });
4267 BorderInfo::new(width, style_val.inner, color, source)
4268 })
4269 .unwrap_or_else(|| default_border.clone());
4270
4271 (top, right, bottom, left)
4272}
4273
4274// +spec:table-layout:c5e446 - table-layout property (auto|fixed) controls layout algorithm selection
4275/// Get the table-layout property for a table node
4276fn get_table_layout_property<T: ParsedFontTrait>(
4277 ctx: &LayoutContext<'_, T>,
4278 node: &LayoutNodeHot,
4279) -> LayoutTableLayout {
4280 let Some(dom_id) = node.dom_node_id else {
4281 return LayoutTableLayout::Auto;
4282 };
4283
4284 let node_data = &ctx.styled_dom.node_data.as_container()[dom_id];
4285 let node_state = ctx.styled_dom.styled_nodes.as_container()[dom_id].styled_node_state.clone();
4286
4287 ctx.styled_dom
4288 .css_property_cache
4289 .ptr
4290 .get_table_layout(node_data, &dom_id, &node_state)
4291 .and_then(|prop| prop.get_property().copied())
4292 .unwrap_or(LayoutTableLayout::Auto)
4293}
4294
4295/// Get the border-collapse property for a table node
4296fn get_border_collapse_property<T: ParsedFontTrait>(
4297 ctx: &LayoutContext<'_, T>,
4298 node: &LayoutNodeHot,
4299) -> StyleBorderCollapse {
4300 let Some(dom_id) = node.dom_node_id else {
4301 return StyleBorderCollapse::Separate;
4302 };
4303
4304 // FAST PATH: compact cache
4305 if let Some(ref cc) = ctx.styled_dom.css_property_cache.ptr.compact_cache {
4306 return cc.get_border_collapse(dom_id.index());
4307 }
4308
4309 let node_data = &ctx.styled_dom.node_data.as_container()[dom_id];
4310 let node_state = ctx.styled_dom.styled_nodes.as_container()[dom_id].styled_node_state.clone();
4311
4312 ctx.styled_dom
4313 .css_property_cache
4314 .ptr
4315 .get_border_collapse(node_data, &dom_id, &node_state)
4316 .and_then(|prop| prop.get_property().copied())
4317 .unwrap_or(StyleBorderCollapse::Separate)
4318}
4319
4320/// Get the border-spacing property for a table node
4321fn get_border_spacing_property<T: ParsedFontTrait>(
4322 ctx: &LayoutContext<'_, T>,
4323 node: &LayoutNodeHot,
4324) -> LayoutBorderSpacing {
4325 if let Some(dom_id) = node.dom_node_id {
4326 // FAST PATH: compact cache
4327 if let Some(ref cc) = ctx.styled_dom.css_property_cache.ptr.compact_cache {
4328 let idx = dom_id.index();
4329 let h_raw = cc.get_border_spacing_h_raw(idx);
4330 let v_raw = cc.get_border_spacing_v_raw(idx);
4331 // If both are non-sentinel, use compact values
4332 if h_raw < azul_css::compact_cache::I16_SENTINEL_THRESHOLD
4333 && v_raw < azul_css::compact_cache::I16_SENTINEL_THRESHOLD
4334 {
4335 return LayoutBorderSpacing::new_separate(
4336 azul_css::props::basic::pixel::PixelValue::px(h_raw as f32 / 10.0),
4337 azul_css::props::basic::pixel::PixelValue::px(v_raw as f32 / 10.0),
4338 );
4339 }
4340 // sentinel → fall through to slow path
4341 }
4342
4343 let node_data = &ctx.styled_dom.node_data.as_container()[dom_id];
4344 let node_state = ctx.styled_dom.styled_nodes.as_container()[dom_id].styled_node_state.clone();
4345
4346 if let Some(prop) = ctx.styled_dom.css_property_cache.ptr.get_border_spacing(
4347 node_data,
4348 &dom_id,
4349 &node_state,
4350 ) {
4351 if let Some(value) = prop.get_property() {
4352 return *value;
4353 }
4354 }
4355 }
4356
4357 LayoutBorderSpacing::default() // Default: 0
4358}
4359
4360/// Get the empty-cells property for a table-cell node.
4361/// Returns Show (default) or Hide.
4362fn get_empty_cells_property<T: ParsedFontTrait>(
4363 ctx: &LayoutContext<'_, T>,
4364 node: &LayoutNodeHot,
4365) -> StyleEmptyCells {
4366 let Some(dom_id) = node.dom_node_id else {
4367 return StyleEmptyCells::Show;
4368 };
4369
4370 let node_data = &ctx.styled_dom.node_data.as_container()[dom_id];
4371 let node_state = ctx.styled_dom.styled_nodes.as_container()[dom_id].styled_node_state.clone();
4372
4373 ctx.styled_dom
4374 .css_property_cache
4375 .ptr
4376 .get_empty_cells(node_data, &dom_id, &node_state)
4377 .and_then(|prop| prop.get_property().copied())
4378 .unwrap_or(StyleEmptyCells::Show)
4379}
4380
4381/// CSS 2.2 Section 17.4 - Tables in the visual formatting model:
4382///
4383/// "The caption box is a block box that retains its own content, padding,
4384/// border, and margin areas. The caption-side property specifies the position
4385/// of the caption box with respect to the table box."
4386///
4387/// Get the caption-side property for a table node.
4388/// Returns Top (default) or Bottom.
4389fn get_caption_side_property<T: ParsedFontTrait>(
4390 ctx: &LayoutContext<'_, T>,
4391 node: &LayoutNodeHot,
4392) -> StyleCaptionSide {
4393 if let Some(dom_id) = node.dom_node_id {
4394 let node_data = &ctx.styled_dom.node_data.as_container()[dom_id];
4395 let node_state = ctx.styled_dom.styled_nodes.as_container()[dom_id].styled_node_state.clone();
4396
4397 if let Some(prop) =
4398 ctx.styled_dom
4399 .css_property_cache
4400 .ptr
4401 .get_caption_side(node_data, &dom_id, &node_state)
4402 {
4403 if let Some(value) = prop.get_property() {
4404 return *value;
4405 }
4406 }
4407 }
4408
4409 StyleCaptionSide::Top // Default per CSS 2.2
4410}
4411
4412// removes entire row or column from display; space made available for other content;
4413// spanned content clipped; does not otherwise affect table layout
4414// +spec:inline-formatting-context:9f5f31 - visibility:collapse for table rows/columns, border-collapse and border-spacing
4415/// CSS 2.2 Section 17.6 - Dynamic row and column effects:
4416///
4417// +spec:box-model:547563 - visibility:collapse removes table rows/columns; elsewhere same as hidden
4418/// "The 'visibility' value 'collapse' removes a row or column from display,
4419/// but it has a different effect than 'visibility: hidden' on other elements.
4420/// When a row or column is collapsed, the space normally occupied by the row
4421/// or column is removed."
4422///
4423/// Check if a node has visibility:collapse set.
4424///
4425/// This is used for table rows and columns to optimize dynamic hiding.
4426/// // +spec:overflow:ebb1f9 - For non-table elements, collapse == hidden (no special handling needed)
4427fn is_visibility_collapsed<T: ParsedFontTrait>(
4428 ctx: &LayoutContext<'_, T>,
4429 node: &LayoutNodeHot,
4430) -> bool {
4431 if let Some(dom_id) = node.dom_node_id {
4432 let node_state = ctx.styled_dom.styled_nodes.as_container()[dom_id].styled_node_state.clone();
4433
4434 if let MultiValue::Exact(value) = get_visibility(ctx.styled_dom, dom_id, &node_state) {
4435 return matches!(value, StyleVisibility::Collapse);
4436 }
4437 }
4438
4439 false
4440}
4441
4442// +spec:overflow:af97a8 - empty-cells in separated borders model; collapsing border overflow
4443// +spec:table-layout:dcdf1b - empty-cells property controls rendering of borders/backgrounds around empty cells in separated borders model
4444/// CSS 2.2 Section 17.6.1.1 - Borders and Backgrounds around empty cells
4445///
4446/// In the separated borders model, the 'empty-cells' property controls the rendering of
4447/// borders and backgrounds around cells that have no visible content. Empty means it has no
4448/// children, or has children that are only collapsed whitespace."
4449///
4450/// Check if a table cell is empty (has no visible content).
4451///
4452/// This is used by the rendering pipeline to decide whether to paint borders/backgrounds
4453/// when empty-cells: hide is set in separated border model.
4454///
4455// in-flow content (including empty elements) other than collapsed whitespace
4456/// A cell is considered empty if:
4457///
4458/// - It has no children, OR
4459/// - It has children but no inline_layout_result (no rendered content)
4460///
4461/// Note: Full whitespace detection would require checking text content during rendering.
4462/// This function provides a basic check suitable for layout phase.
4463fn is_cell_empty(tree: &LayoutTree, cell_index: usize) -> bool {
4464 if tree.get(cell_index).is_none() {
4465 return true; // Invalid cell is considered empty
4466 }
4467
4468 // No children = empty
4469 if tree.children(cell_index).is_empty() {
4470 return true;
4471 }
4472
4473 // If cell has an inline layout result, check if it's empty
4474 if let Some(warm_node) = tree.warm(cell_index) {
4475 if let Some(ref cached_layout) = warm_node.inline_layout_result {
4476 // Check if inline layout has any rendered content
4477 // Empty inline layouts have no items (glyphs/fragments)
4478 // Note: This is a heuristic - full detection requires text content analysis
4479 return cached_layout.layout.items.is_empty();
4480 }
4481 }
4482
4483 // Check if all children have no content
4484 // A more thorough check would recursively examine all descendants
4485 //
4486 // For now, we use a simple heuristic: if there are children, assume not empty
4487 // unless proven otherwise by inline_layout_result
4488
4489 // Cell with children but no inline layout = likely has block-level content = not empty
4490 false
4491}
4492
4493/// Main function to layout a table formatting context
4494// +spec:table-layout:235e8e - CSS 2.2 §17.1-17.2 table model: fixed/auto algorithms, row/column/cell/caption structure
4495// +spec:table-layout:a6422d - CSS table model: table structure analysis, row/column/cell layout, caption, border-collapse
4496pub fn layout_table_fc<T: ParsedFontTrait>(
4497 ctx: &mut LayoutContext<'_, T>,
4498 tree: &mut LayoutTree,
4499 text_cache: &mut crate::font_traits::TextLayoutCache,
4500 node_index: usize,
4501 constraints: &LayoutConstraints,
4502) -> Result<LayoutOutput> {
4503 debug_log!(ctx, "Laying out table");
4504
4505 debug_table_layout!(
4506 ctx,
4507 "node_index={}, available_size={:?}, writing_mode={:?}",
4508 node_index,
4509 constraints.available_size,
4510 constraints.writing_mode
4511 );
4512
4513 // Multi-pass table layout algorithm:
4514 //
4515 // 1. Analyze table structure - identify rows, cells, columns
4516 // 2. Determine table-layout property (fixed vs auto)
4517 // 3. Calculate column widths
4518 // 4. Layout cells and calculate row heights
4519 // 5. Position cells in final grid
4520
4521 // Get the table node to read CSS properties
4522 let table_node = tree
4523 .get(node_index)
4524 .ok_or(LayoutError::InvalidTree)?
4525 .clone();
4526
4527 // Calculate the table's border-box width for column distribution
4528 // This accounts for the table's own width property (e.g., width: 100%)
4529 let table_border_box_width = if let Some(dom_id) = table_node.dom_node_id {
4530 // Use calculate_used_size_for_node to resolve table width (respects width:100%)
4531 let intrinsic = tree.warm(node_index).and_then(|w| w.intrinsic_sizes).unwrap_or_default();
4532 let containing_block_size = LogicalSize {
4533 width: constraints.available_size.width,
4534 height: constraints.available_size.height,
4535 };
4536
4537 let table_bp = table_node.box_props.unpack();
4538 let table_size = crate::solver3::sizing::calculate_used_size_for_node(
4539 ctx.styled_dom,
4540 Some(dom_id),
4541 containing_block_size,
4542 intrinsic,
4543 &table_bp,
4544 ctx.viewport_size,
4545 )?;
4546
4547 table_size.width
4548 } else {
4549 constraints.available_size.width
4550 };
4551
4552 // Subtract padding and border to get content-box width for column distribution
4553 let tbp = table_node.box_props.unpack();
4554 let table_content_box_width = {
4555 let padding_width = tbp.padding.left + tbp.padding.right;
4556 let border_width = tbp.border.left + tbp.border.right;
4557 (table_border_box_width - padding_width - border_width).max(0.0)
4558 };
4559
4560 debug_table_layout!(ctx, "Table Layout Debug");
4561 debug_table_layout!(ctx, "Node index: {}", node_index);
4562 debug_table_layout!(
4563 ctx,
4564 "Available size from parent: {:.2} x {:.2}",
4565 constraints.available_size.width,
4566 constraints.available_size.height
4567 );
4568 debug_table_layout!(ctx, "Table border-box width: {:.2}", table_border_box_width);
4569 debug_table_layout!(
4570 ctx,
4571 "Table content-box width: {:.2}",
4572 table_content_box_width
4573 );
4574 debug_table_layout!(
4575 ctx,
4576 "Table padding: L={:.2} R={:.2}",
4577 tbp.padding.left,
4578 tbp.padding.right
4579 );
4580 debug_table_layout!(
4581 ctx,
4582 "Table border: L={:.2} R={:.2}",
4583 tbp.border.left,
4584 tbp.border.right
4585 );
4586 debug_table_layout!(ctx, "=");
4587
4588 // Phase 1: Analyze table structure
4589 let mut table_ctx = analyze_table_structure(tree, node_index, ctx)?;
4590
4591 // +spec:table-layout:ff5671 - table-layout property (fixed vs auto) controls column width algorithm
4592 // +spec:width-calculation:7a5b23 - table-layout property determines fixed vs auto algorithm (CSS 2.2 §17.5.2)
4593 // Phase 2: Read CSS properties and determine layout algorithm
4594 let table_layout = get_table_layout_property(ctx, &table_node);
4595 table_ctx.use_fixed_layout = matches!(table_layout, LayoutTableLayout::Fixed);
4596
4597 // +spec:containing-block:cc1453 - collapsing border model: border-collapse property drives table border handling
4598 // Read border properties
4599 table_ctx.border_collapse = get_border_collapse_property(ctx, &table_node);
4600 table_ctx.border_spacing = get_border_spacing_property(ctx, &table_node);
4601
4602 debug_log!(
4603 ctx,
4604 "Table layout: {:?}, border-collapse: {:?}, border-spacing: {:?}",
4605 table_layout,
4606 table_ctx.border_collapse,
4607 table_ctx.border_spacing
4608 );
4609
4610 // +spec:width-calculation:431d60 - fixed vs auto table layout column width algorithms (CSS 2.2 §17.5.2.1, §17.5.2.2)
4611 // Phase 3: Calculate column widths
4612 if table_ctx.use_fixed_layout {
4613 // DEBUG: Log available width passed into fixed column calculation
4614 debug_table_layout!(
4615 ctx,
4616 "FIXED layout: table_content_box_width={:.2}",
4617 table_content_box_width
4618 );
4619 calculate_column_widths_fixed(ctx, tree, &mut table_ctx, table_content_box_width);
4620 } else {
4621 // Pass table_content_box_width for column distribution in auto layout
4622 calculate_column_widths_auto_with_width(
4623 &mut table_ctx,
4624 tree,
4625 text_cache,
4626 ctx,
4627 constraints,
4628 table_content_box_width,
4629 )?;
4630 }
4631
4632 debug_table_layout!(ctx, "After column width calculation:");
4633 debug_table_layout!(ctx, " Number of columns: {}", table_ctx.columns.len());
4634 for (i, col) in table_ctx.columns.iter().enumerate() {
4635 debug_table_layout!(
4636 ctx,
4637 " Column {}: width={:.2}",
4638 i,
4639 col.computed_width.unwrap_or(0.0)
4640 );
4641 }
4642 let total_col_width: f32 = table_ctx
4643 .columns
4644 .iter()
4645 .filter_map(|c| c.computed_width)
4646 .sum();
4647 debug_table_layout!(ctx, " Total column width: {:.2}", total_col_width);
4648
4649 // Phase 4: Calculate row heights based on cell content
4650 calculate_row_heights(&mut table_ctx, tree, text_cache, ctx, constraints)?;
4651
4652 // Phase 5: Position cells in final grid and collect positions
4653 let mut cell_positions =
4654 position_table_cells(&mut table_ctx, tree, ctx, node_index, constraints)?;
4655
4656 // Calculate final table size including border-spacing
4657 let mut table_width: f32 = table_ctx
4658 .columns
4659 .iter()
4660 .filter_map(|col| col.computed_width)
4661 .sum();
4662 let mut table_height: f32 = table_ctx.row_heights.iter().sum();
4663
4664 debug_table_layout!(
4665 ctx,
4666 "After calculate_row_heights: table_height={:.2}, row_heights={:?}",
4667 table_height,
4668 table_ctx.row_heights
4669 );
4670
4671 // +spec:box-model:494f6b - collapsing border model: row-width formula and table border width computation
4672 // +spec:box-model:e7d0a3 - Separated borders model: border-spacing, empty-cells, collapsing border width calculation
4673 // +spec:box-sizing:ee702c - separated borders model: border-spacing between adjoining cells
4674 // Add border-spacing to table size if border-collapse is separate
4675 // +spec:box-model:acb81f - separated borders model: border-spacing between adjoining cell borders
4676 // +spec:box-model:e480b1 - table width = left inner padding edge to right inner padding edge (including border-spacing)
4677 if table_ctx.border_collapse == StyleBorderCollapse::Separate {
4678 use get_element_font_size;
4679 use get_parent_font_size;
4680 use get_root_font_size;
4681 use PhysicalSize;
4682 use PropertyContext;
4683 use ResolutionContext;
4684
4685 let styled_dom = ctx.styled_dom;
4686 let table_id = tree.nodes[node_index].dom_node_id.unwrap();
4687 let table_state = &styled_dom.styled_nodes.as_container()[table_id].styled_node_state;
4688
4689 let spacing_context = ResolutionContext {
4690 element_font_size: get_element_font_size(styled_dom, table_id, table_state),
4691 parent_font_size: get_parent_font_size(styled_dom, table_id, table_state),
4692 root_font_size: get_root_font_size(styled_dom, table_state),
4693 containing_block_size: PhysicalSize::new(0.0, 0.0),
4694 element_size: None,
4695 viewport_size: PhysicalSize::new(ctx.viewport_size.width, ctx.viewport_size.height),
4696 };
4697
4698 let h_spacing = table_ctx
4699 .border_spacing
4700 .horizontal
4701 .resolve_with_context(&spacing_context, PropertyContext::Other)
4702 .max(0.0);
4703 let v_spacing = table_ctx
4704 .border_spacing
4705 .vertical
4706 .resolve_with_context(&spacing_context, PropertyContext::Other)
4707 .max(0.0);
4708
4709 // Add spacing: left + (n-1 between columns) + right = n+1 spacings
4710 let num_cols = table_ctx.columns.len();
4711 if num_cols > 0 {
4712 table_width += h_spacing * (num_cols + 1) as f32;
4713 }
4714
4715 // Add spacing: top + (n-1 between rows) + bottom = n+1 spacings
4716 if table_ctx.num_rows > 0 {
4717 let full_spacings = (table_ctx.num_rows + 1) as f32;
4718 // Each hidden-empty row loses one side of border-spacing
4719 let hidden_empty_count = table_ctx.hidden_empty_rows.len() as f32;
4720 table_height += v_spacing * (full_spacings - hidden_empty_count);
4721 }
4722 }
4723
4724 // +spec:table-layout:24dbf9 - §17.4 table wrapper box model: caption positioning, BFC establishment
4725 // +spec:width-calculation:600f98 - caption-side positions caption above/below table box (CSS 2.2 §17.4)
4726 // CSS 2.2 Section 17.4: Layout and position the caption if present
4727 //
4728 // "The caption box is a block box that retains its own content,
4729 // padding, border, and margin areas."
4730 let caption_side = get_caption_side_property(ctx, &table_node);
4731 let mut caption_height = 0.0;
4732 let mut table_y_offset = 0.0;
4733
4734 if let Some(caption_idx) = table_ctx.caption_index {
4735 debug_log!(
4736 ctx,
4737 "Laying out caption with caption-side: {:?}",
4738 caption_side
4739 );
4740
4741 // Layout caption as a block with the table's width as available width
4742 let caption_constraints = LayoutConstraints {
4743 available_size: LogicalSize {
4744 width: table_width,
4745 height: constraints.available_size.height,
4746 },
4747 writing_mode: constraints.writing_mode,
4748 writing_mode_ctx: constraints.writing_mode_ctx,
4749 bfc_state: None, // Caption creates its own BFC
4750 text_align: constraints.text_align,
4751 containing_block_size: constraints.containing_block_size,
4752 available_width_type: Text3AvailableSpace::Definite(table_width),
4753 };
4754
4755 // Layout the caption node
4756 let mut empty_float_cache = HashMap::new();
4757 let caption_result = layout_formatting_context(
4758 ctx,
4759 tree,
4760 text_cache,
4761 caption_idx,
4762 &caption_constraints,
4763 &mut empty_float_cache,
4764 )?;
4765 caption_height = caption_result.output.overflow_size.height;
4766
4767 let caption_position = match caption_side {
4768 StyleCaptionSide::Top => {
4769 // Caption on top: position at y=0, table starts below caption
4770 table_y_offset = caption_height;
4771 LogicalPosition { x: 0.0, y: 0.0 }
4772 }
4773 StyleCaptionSide::Bottom => {
4774 // Caption on bottom: table starts at y=0, caption below table
4775 LogicalPosition {
4776 x: 0.0,
4777 y: table_height,
4778 }
4779 }
4780 };
4781
4782 // Add caption position to the positions map
4783 cell_positions.insert(caption_idx, caption_position);
4784
4785 debug_log!(
4786 ctx,
4787 "Caption positioned at x={:.2}, y={:.2}, height={:.2}",
4788 caption_position.x,
4789 caption_position.y,
4790 caption_height
4791 );
4792 }
4793
4794 // Adjust all table cell positions if caption is on top
4795 if table_y_offset > 0.0 {
4796 debug_log!(
4797 ctx,
4798 "Adjusting table cells by y offset: {:.2}",
4799 table_y_offset
4800 );
4801
4802 // Adjust cell positions in the map
4803 for cell_info in &table_ctx.cells {
4804 if let Some(pos) = cell_positions.get_mut(&cell_info.node_index) {
4805 pos.y += table_y_offset;
4806 }
4807 }
4808 }
4809
4810 let total_height = table_height + caption_height;
4811
4812 debug_table_layout!(ctx, "Final table dimensions:");
4813 debug_table_layout!(ctx, " Content width (columns): {:.2}", table_width);
4814 debug_table_layout!(ctx, " Content height (rows): {:.2}", table_height);
4815 debug_table_layout!(ctx, " Caption height: {:.2}", caption_height);
4816 debug_table_layout!(ctx, " Total height: {:.2}", total_height);
4817 debug_table_layout!(ctx, "End Table Debug");
4818
4819 // Create output with the table's final size and cell positions
4820 // +spec:box-model:52fcfe - overflow_size must include borders that spill into margin in collapsing border model
4821 let output = LayoutOutput {
4822 overflow_size: LogicalSize {
4823 width: table_width,
4824 height: total_height,
4825 },
4826 // Cell positions calculated in position_table_cells
4827 positions: cell_positions,
4828 // line box or first in-flow table-row; if none, bottom of content edge
4829 // TODO: implement proper table baseline propagation
4830 baseline: None,
4831 };
4832
4833 Ok(output)
4834}
4835
4836// +spec:display-property:f47f8a - Table structure analysis: caption positioning, row/column/row-group traversal per CSS 2.2 §17.4-17.5
4837/// Analyze the table structure to identify rows, cells, and columns
4838fn analyze_table_structure<T: ParsedFontTrait>(
4839 tree: &LayoutTree,
4840 table_index: usize,
4841 ctx: &mut LayoutContext<'_, T>,
4842) -> Result<TableLayoutContext> {
4843 let mut table_ctx = TableLayoutContext::new();
4844
4845 let table_node = tree.get(table_index).ok_or(LayoutError::InvalidTree)?;
4846
4847 // +spec:width-calculation:0a2766 - table internal elements form rectangular grid of rows/columns (CSS 2.2 §17.5)
4848 // CSS 2.2 Section 17.4: A table may have one table-caption child.
4849 // Traverse children to find caption, columns/colgroups, rows, and row groups
4850 for &child_idx in tree.children(table_index) {
4851 if let Some(child) = tree.get(child_idx) {
4852 // Check if this is a table caption
4853 if matches!(child.formatting_context, FormattingContext::TableCaption) {
4854 debug_log!(ctx, "Found table caption at index {}", child_idx);
4855 table_ctx.caption_index = Some(child_idx);
4856 continue;
4857 }
4858
4859 // CSS 2.2 Section 17.2: Check for column groups
4860 if matches!(
4861 child.formatting_context,
4862 FormattingContext::TableColumnGroup
4863 ) {
4864 analyze_table_colgroup(tree, child_idx, &mut table_ctx, ctx)?;
4865 continue;
4866 }
4867
4868 // Check if this is a table row or row group
4869 match child.formatting_context {
4870 FormattingContext::TableRow => {
4871 analyze_table_row(tree, child_idx, &mut table_ctx, ctx)?;
4872 }
4873 FormattingContext::TableRowGroup => {
4874 // Process rows within the row group
4875 for &row_idx in tree.children(child_idx) {
4876 if let Some(row) = tree.get(row_idx) {
4877 if matches!(row.formatting_context, FormattingContext::TableRow) {
4878 analyze_table_row(tree, row_idx, &mut table_ctx, ctx)?;
4879 }
4880 }
4881 }
4882 }
4883 _ => {}
4884 }
4885 }
4886 }
4887
4888 debug_log!(
4889 ctx,
4890 "Table structure: {} rows, {} columns, {} cells{}",
4891 table_ctx.num_rows,
4892 table_ctx.columns.len(),
4893 table_ctx.cells.len(),
4894 if table_ctx.caption_index.is_some() {
4895 ", has caption"
4896 } else {
4897 ""
4898 }
4899 );
4900
4901 Ok(table_ctx)
4902}
4903
4904/// Analyze a table column group to identify columns and track collapsed columns
4905///
4906/// - CSS 2.2 Section 17.2: Column groups contain columns
4907/// - CSS 2.2 Section 17.6: Columns can have visibility:collapse
4908fn analyze_table_colgroup<T: ParsedFontTrait>(
4909 tree: &LayoutTree,
4910 colgroup_index: usize,
4911 table_ctx: &mut TableLayoutContext,
4912 ctx: &mut LayoutContext<'_, T>,
4913) -> Result<()> {
4914 let colgroup_node = tree.get(colgroup_index).ok_or(LayoutError::InvalidTree)?;
4915
4916 // Check if the colgroup itself has visibility:collapse
4917 if is_visibility_collapsed(ctx, colgroup_node) {
4918 // All columns in this group should be collapsed
4919 // TODO: For now, just mark the group (actual column indices will be determined later)
4920 debug_log!(
4921 ctx,
4922 "Column group at index {} has visibility:collapse",
4923 colgroup_index
4924 );
4925 }
4926
4927 // Check for individual column elements within the group
4928 for &col_idx in tree.children(colgroup_index) {
4929 if let Some(col_node) = tree.get(col_idx) {
4930 // Note: Individual columns don't have a FormattingContext::TableColumn
4931 // They are represented as children of TableColumnGroup
4932 // Check visibility:collapse on each column
4933 if is_visibility_collapsed(ctx, col_node) {
4934 // We need to determine the actual column index this represents
4935 // For now, we'll track it during cell analysis
4936 debug_log!(ctx, "Column at index {} has visibility:collapse", col_idx);
4937 }
4938 }
4939 }
4940
4941 Ok(())
4942}
4943
4944// +spec:display-property:7f167c - Table grid cell placement: rows fill table top-to-bottom, cells placed left-to-right with colspan/rowspan
4945/// Analyze a table row to identify cells and update column count
4946fn analyze_table_row<T: ParsedFontTrait>(
4947 tree: &LayoutTree,
4948 row_index: usize,
4949 table_ctx: &mut TableLayoutContext,
4950 ctx: &mut LayoutContext<'_, T>,
4951) -> Result<()> {
4952 // +spec:inline-formatting-context:3f8091 - table visual layout: cells occupy grid cells, row/column spanning
4953 let row_node = tree.get(row_index).ok_or(LayoutError::InvalidTree)?;
4954 let row_num = table_ctx.num_rows;
4955 table_ctx.num_rows += 1;
4956 // Track the layout tree index for this row (for positioning/painting)
4957 if table_ctx.row_node_indices.len() <= row_num {
4958 table_ctx.row_node_indices.resize(row_num + 1, 0);
4959 }
4960 table_ctx.row_node_indices[row_num] = row_index;
4961
4962 // CSS 2.2 Section 17.6: Check if this row has visibility:collapse
4963 if is_visibility_collapsed(ctx, row_node) {
4964 debug_log!(ctx, "Row {} has visibility:collapse", row_num);
4965 table_ctx.collapsed_rows.insert(row_num);
4966 }
4967
4968 let mut col_index = 0;
4969
4970 for &cell_idx in tree.children(row_index) {
4971 if let Some(cell) = tree.get(cell_idx) {
4972 if matches!(cell.formatting_context, FormattingContext::TableCell) {
4973 // Get colspan and rowspan (TODO: from CSS properties)
4974 let colspan = 1; // TODO: Get from CSS
4975 let rowspan = 1; // TODO: Get from CSS
4976
4977 let cell_info = TableCellInfo {
4978 node_index: cell_idx,
4979 column: col_index,
4980 colspan,
4981 row: row_num,
4982 rowspan,
4983 };
4984
4985 table_ctx.cells.push(cell_info);
4986
4987 // Update column count
4988 let max_col = col_index + colspan;
4989 while table_ctx.columns.len() < max_col {
4990 table_ctx.columns.push(TableColumnInfo {
4991 min_width: 0.0,
4992 max_width: 0.0,
4993 computed_width: None,
4994 });
4995 }
4996
4997 col_index += colspan;
4998 }
4999 }
5000 }
5001
5002 Ok(())
5003}
5004
5005// +spec:overflow:66f584 - Fixed table layout: cells use overflow property to clip overflowing content
5006// +spec:positioning:46070a - Fixed table layout (17.5.2.1) and auto table layout (17.5.2.2) column width algorithms
5007// +spec:table-layout:875401 - Fixed table layout algorithm (17.5.2.1): column widths from first-row cells, remaining columns divide space equally, table width = max(width property, sum of columns)
5008/// Calculate column widths using the fixed table layout algorithm
5009/// // +spec:overflow:de613c - Fixed table layout algorithm (CSS 2.2 Section 17.5.2.1)
5010// +spec:table-layout:8b72b3 - fixed table layout: column width from column elements/first-row cells, remaining columns equal division
5011///
5012/// CSS 2.2 Section 17.5.2.1: In fixed table layout, the horizontal layout
5013/// does not depend on cell contents. Column widths are determined by:
5014/// 1. Column elements with explicit (non-auto) width
5015/// 2. First-row cells with explicit (non-auto) width
5016/// 3. Remaining columns equally divide remaining horizontal space
5017///
5018/// CSS 2.2 Section 17.6: Columns with visibility:collapse are excluded
5019/// from width calculations
5020// +spec:table-layout:c5e446 - Fixed table layout algorithm: column widths from col elements or first-row cells, remaining columns divide equally
5021/// +spec:width-calculation:8c958a - Fixed table layout: column widths from col elements, first-row cells, then equal distribution (CSS 2.2 §17.5.2.1)
5022fn calculate_column_widths_fixed<T: ParsedFontTrait>(
5023 ctx: &mut LayoutContext<'_, T>,
5024 tree: &LayoutTree,
5025 table_ctx: &mut TableLayoutContext,
5026 available_width: f32,
5027) {
5028 debug_table_layout!(
5029 ctx,
5030 "calculate_column_widths_fixed: num_cols={}, available_width={:.2}",
5031 table_ctx.columns.len(),
5032 available_width
5033 );
5034
5035 let num_cols = table_ctx.columns.len();
5036 if num_cols == 0 {
5037 return;
5038 }
5039
5040 let num_visible_cols = num_cols - table_ctx.collapsed_columns.len();
5041 if num_visible_cols == 0 {
5042 for col in &mut table_ctx.columns {
5043 col.computed_width = Some(0.0);
5044 }
5045 return;
5046 }
5047
5048 // Step 1 (column elements) is skipped because column elements don't store
5049 // explicit widths in the current table structure analysis.
5050 // Step 2: Check first-row cells for explicit width properties.
5051 let mut col_has_width = vec![false; num_cols];
5052
5053 for cell_info in &table_ctx.cells {
5054 if cell_info.row != 0 {
5055 continue; // Only consider cells in the first row
5056 }
5057 if table_ctx.collapsed_columns.contains(&cell_info.column) {
5058 continue;
5059 }
5060
5061 // Look up the cell's CSS width via its dom_node_id
5062 let dom_id = match tree.get(cell_info.node_index).and_then(|n| n.dom_node_id) {
5063 Some(id) => id,
5064 None => continue,
5065 };
5066
5067 let node_state = &ctx.styled_dom.styled_nodes.as_container()[dom_id].styled_node_state;
5068 let css_width = get_css_width(ctx.styled_dom, dom_id, &node_state);
5069
5070 let explicit_px = match css_width.unwrap_or_default() {
5071 LayoutWidth::Px(px) => {
5072 resolve_size_metric(
5073 px.metric,
5074 px.number.get(),
5075 available_width,
5076 ctx.viewport_size,
5077 )
5078 }
5079 LayoutWidth::Auto | LayoutWidth::MinContent | LayoutWidth::MaxContent
5080 | LayoutWidth::Calc(_) | LayoutWidth::FitContent(_) => continue,
5081 };
5082
5083 if cell_info.colspan == 1 {
5084 table_ctx.columns[cell_info.column].computed_width = Some(explicit_px);
5085 col_has_width[cell_info.column] = true;
5086 } else {
5087 let mut visible_span_count = 0;
5088 for offset in 0..cell_info.colspan {
5089 let col_idx = cell_info.column + offset;
5090 if col_idx < num_cols && !table_ctx.collapsed_columns.contains(&col_idx) {
5091 visible_span_count += 1;
5092 }
5093 }
5094 if visible_span_count > 0 {
5095 let per_col = explicit_px / visible_span_count as f32;
5096 for offset in 0..cell_info.colspan {
5097 let col_idx = cell_info.column + offset;
5098 if col_idx < num_cols
5099 && !table_ctx.collapsed_columns.contains(&col_idx)
5100 && !col_has_width[col_idx]
5101 {
5102 table_ctx.columns[col_idx].computed_width = Some(per_col);
5103 col_has_width[col_idx] = true;
5104 }
5105 }
5106 }
5107 }
5108 }
5109
5110 let used_width: f32 = table_ctx.columns.iter().enumerate()
5111 .filter(|(idx, _)| col_has_width[*idx] && !table_ctx.collapsed_columns.contains(idx))
5112 .filter_map(|(_, c)| c.computed_width)
5113 .sum();
5114 let remaining_width = (available_width - used_width).max(0.0);
5115 let num_remaining = table_ctx.columns.iter().enumerate()
5116 .filter(|(idx, _)| !col_has_width[*idx] && !table_ctx.collapsed_columns.contains(idx))
5117 .count();
5118
5119 if num_remaining > 0 {
5120 let width_per_remaining = remaining_width / num_remaining as f32;
5121 for (col_idx, col) in table_ctx.columns.iter_mut().enumerate() {
5122 if table_ctx.collapsed_columns.contains(&col_idx) {
5123 col.computed_width = Some(0.0);
5124 } else if !col_has_width[col_idx] {
5125 col.computed_width = Some(width_per_remaining);
5126 }
5127 }
5128 }
5129
5130 // Set collapsed columns to zero width
5131 for (col_idx, col) in table_ctx.columns.iter_mut().enumerate() {
5132 if table_ctx.collapsed_columns.contains(&col_idx) {
5133 col.computed_width = Some(0.0);
5134 }
5135 }
5136
5137 let total_col_width: f32 = table_ctx.columns.iter()
5138 .filter_map(|c| c.computed_width)
5139 .sum();
5140 if available_width > total_col_width && num_visible_cols > 0 {
5141 let extra = available_width - total_col_width;
5142 let extra_per_col = extra / num_visible_cols as f32;
5143 for (col_idx, col) in table_ctx.columns.iter_mut().enumerate() {
5144 if !table_ctx.collapsed_columns.contains(&col_idx) {
5145 if let Some(ref mut w) = col.computed_width {
5146 *w += extra_per_col;
5147 }
5148 }
5149 }
5150 }
5151}
5152
5153/// Recursively clear the layout cache for every node in a subtree.
5154///
5155/// A fixed-depth walk is not enough: a table cell like
5156/// `<td><span><a>text</a></span></td>` has 4+ levels once the anonymous IFC
5157/// wrapper is inserted, and any stale cache below that level would feed a
5158/// narrow intrinsic width back into `measure_cell_content_width`.
5159fn clear_subtree_cache(
5160 tree: &LayoutTree,
5161 cache_map: &mut crate::solver3::cache::LayoutCacheMap,
5162 root: usize,
5163) {
5164 if root < cache_map.entries.len() {
5165 cache_map.entries[root].clear();
5166 }
5167 let child_ids: Vec<usize> = tree.children(root).to_vec();
5168 for child in child_ids {
5169 clear_subtree_cache(tree, cache_map, child);
5170 }
5171}
5172
5173/// Measure a cell's content width for a given intrinsic sizing mode.
5174///
5175/// CSS 2.2 Section 17.5.2.2: shared helper for min-content and max-content
5176/// width measurement. Lays out the cell subtree in ComputeSize mode and
5177/// returns the border-box width (content + padding + border).
5178fn measure_cell_content_width<T: ParsedFontTrait>(
5179 ctx: &mut LayoutContext<'_, T>,
5180 tree: &mut LayoutTree,
5181 text_cache: &mut crate::font_traits::TextLayoutCache,
5182 cell_index: usize,
5183 constraints: &LayoutConstraints,
5184 sizing_mode: crate::text3::cache::AvailableSpace,
5185) -> Result<f32> {
5186 let width_type = match sizing_mode {
5187 crate::text3::cache::AvailableSpace::MinContent => Text3AvailableSpace::MinContent,
5188 crate::text3::cache::AvailableSpace::MaxContent => Text3AvailableSpace::MaxContent,
5189 crate::text3::cache::AvailableSpace::Definite(w) => Text3AvailableSpace::Definite(w),
5190 };
5191 let cell_constraints = LayoutConstraints {
5192 available_size: LogicalSize {
5193 width: sizing_mode.to_f32_for_layout(),
5194 height: f32::INFINITY,
5195 },
5196 writing_mode: constraints.writing_mode,
5197 writing_mode_ctx: constraints.writing_mode_ctx,
5198 bfc_state: None,
5199 text_align: constraints.text_align,
5200 containing_block_size: constraints.containing_block_size,
5201 available_width_type: width_type,
5202 };
5203
5204 let mut temp_positions: super::PositionVec = Vec::new();
5205 let mut temp_scrollbar_reflow = false;
5206 let mut temp_float_cache = HashMap::new();
5207
5208 // Clear cached layout for this cell and ALL its descendants so that
5209 // min/max-content measurement uses unconstrained width, not a stale
5210 // result from a previous pass with narrower constraints. Deeply nested
5211 // inlines (`<td><span><a>text</a></span></td>`) need recursion; a fixed
5212 // 2-level walk left the `<a>` at level 3 with a stale cached 0-width.
5213 clear_subtree_cache(tree, &mut ctx.cache_map, cell_index);
5214
5215 crate::solver3::cache::calculate_layout_for_subtree(
5216 ctx,
5217 tree,
5218 text_cache,
5219 cell_index,
5220 LogicalPosition::zero(),
5221 cell_constraints.available_size,
5222 &mut temp_positions,
5223 &mut temp_scrollbar_reflow,
5224 &mut temp_float_cache,
5225 crate::solver3::cache::ComputeMode::ComputeSize,
5226 )?;
5227
5228 let cell_bp = tree.get(cell_index)
5229 .ok_or(LayoutError::InvalidTree)?
5230 .box_props.unpack();
5231 let padding = &cell_bp.padding;
5232 let border = &cell_bp.border;
5233 let wm = constraints.writing_mode;
5234
5235 // For min/max-content measurement, use the overflow content size (actual
5236 // content width) rather than used_size. used_size for auto-width blocks
5237 // fills the containing block, which is huge (f32::MAX/2) during
5238 // intrinsic sizing — that would make every column appear infinitely wide.
5239 let content_width = tree.warm(cell_index)
5240 .and_then(|w| w.overflow_content_size)
5241 .map(|s| s.width)
5242 .unwrap_or_else(|| {
5243 tree.get(cell_index)
5244 .and_then(|n| n.used_size)
5245 .map(|s| s.width)
5246 .unwrap_or(0.0)
5247 });
5248
5249 Ok(content_width
5250 + padding.cross_start(wm) + padding.cross_end(wm)
5251 + border.cross_start(wm) + border.cross_end(wm))
5252}
5253
5254/// Measure a cell's minimum content width (with maximum wrapping)
5255fn measure_cell_min_content_width<T: ParsedFontTrait>(
5256 ctx: &mut LayoutContext<'_, T>,
5257 tree: &mut LayoutTree,
5258 text_cache: &mut crate::font_traits::TextLayoutCache,
5259 cell_index: usize,
5260 constraints: &LayoutConstraints,
5261) -> Result<f32> {
5262 measure_cell_content_width(
5263 ctx, tree, text_cache, cell_index, constraints,
5264 crate::text3::cache::AvailableSpace::MinContent,
5265 )
5266}
5267
5268/// Measure a cell's maximum content width (without wrapping)
5269fn measure_cell_max_content_width<T: ParsedFontTrait>(
5270 ctx: &mut LayoutContext<'_, T>,
5271 tree: &mut LayoutTree,
5272 text_cache: &mut crate::font_traits::TextLayoutCache,
5273 cell_index: usize,
5274 constraints: &LayoutConstraints,
5275) -> Result<f32> {
5276 measure_cell_content_width(
5277 ctx, tree, text_cache, cell_index, constraints,
5278 crate::text3::cache::AvailableSpace::MaxContent,
5279 )
5280}
5281
5282/// Calculate column widths using the auto table layout algorithm
5283fn calculate_column_widths_auto<T: ParsedFontTrait>(
5284 table_ctx: &mut TableLayoutContext,
5285 tree: &mut LayoutTree,
5286 text_cache: &mut crate::font_traits::TextLayoutCache,
5287 ctx: &mut LayoutContext<'_, T>,
5288 constraints: &LayoutConstraints,
5289) -> Result<()> {
5290 calculate_column_widths_auto_with_width(
5291 table_ctx,
5292 tree,
5293 text_cache,
5294 ctx,
5295 constraints,
5296 constraints.available_size.width,
5297 )
5298}
5299
5300/// Calculate column widths using the auto table layout algorithm with explicit table width
5301// +spec:display-property:05c8e8 - CSS 2.2 §17.5.2.2 automatic table layout: column min/max widths, table width = max(W or CB, CAPMIN, MIN), extra width distributed over columns
5302/// +spec:overflow:29edde - CSS 2.2 §17.5.2.2 automatic table layout: MCW/max-content per cell, column min/max, colspan distribution, final width determination
5303// +spec:table-layout:23a215 - automatic table layout: MCW/max cell widths, column min/max, colspan distribution, table width from MAX/MIN/CAPMIN
5304// +spec:table-layout:5e1145 - Automatic table layout: MCW/max-content per cell, column min/max, colspan distribution, final width from MIN/MAX
5305// +spec:width-calculation:42dfca - CSS 2.2 §17.5.2.2 automatic table layout: MCW/max-content per cell, column min/max, multi-span distribution, final table width
5306/// +spec:width-calculation:335ef1 - Automatic table layout: width given by column widths and borders (CSS 2.2 §17.5.2.2)
5307fn calculate_column_widths_auto_with_width<T: ParsedFontTrait>(
5308 table_ctx: &mut TableLayoutContext,
5309 tree: &mut LayoutTree,
5310 text_cache: &mut crate::font_traits::TextLayoutCache,
5311 ctx: &mut LayoutContext<'_, T>,
5312 constraints: &LayoutConstraints,
5313 table_width: f32,
5314) -> Result<()> {
5315 // Auto layout: calculate min/max content width for each cell
5316 let num_cols = table_ctx.columns.len();
5317 if num_cols == 0 {
5318 return Ok(());
5319 }
5320
5321 // Step 1: Measure all cells to determine column min/max widths
5322 // CSS 2.2 Section 17.6: Skip cells in collapsed columns
5323 for cell_info in &table_ctx.cells {
5324 // Skip cells in collapsed columns
5325 if table_ctx.collapsed_columns.contains(&cell_info.column) {
5326 continue;
5327 }
5328
5329 // Skip cells that span into collapsed columns
5330 let mut spans_collapsed = false;
5331 for col_offset in 0..cell_info.colspan {
5332 if table_ctx
5333 .collapsed_columns
5334 .contains(&(cell_info.column + col_offset))
5335 {
5336 spans_collapsed = true;
5337 break;
5338 }
5339 }
5340 if spans_collapsed {
5341 continue;
5342 }
5343
5344 let min_width = measure_cell_min_content_width(
5345 ctx,
5346 tree,
5347 text_cache,
5348 cell_info.node_index,
5349 constraints,
5350 )?;
5351
5352 let max_width = measure_cell_max_content_width(
5353 ctx,
5354 tree,
5355 text_cache,
5356 cell_info.node_index,
5357 constraints,
5358 )?;
5359
5360 // Handle single-column cells
5361 if cell_info.colspan == 1 {
5362 let col = &mut table_ctx.columns[cell_info.column];
5363 col.min_width = col.min_width.max(min_width);
5364 col.max_width = col.max_width.max(max_width);
5365 } else {
5366 // Handle multi-column cells (colspan > 1)
5367 // Distribute the cell's min/max width across the spanned columns
5368 distribute_cell_width_across_columns(
5369 &mut table_ctx.columns,
5370 cell_info.column,
5371 cell_info.colspan,
5372 min_width,
5373 max_width,
5374 &table_ctx.collapsed_columns,
5375 );
5376 }
5377 }
5378
5379 // Step 2: Calculate final column widths based on available space
5380 // Exclude collapsed columns from total width calculations
5381 let total_min_width: f32 = table_ctx
5382 .columns
5383 .iter()
5384 .enumerate()
5385 .filter(|(idx, _)| !table_ctx.collapsed_columns.contains(idx))
5386 .map(|(_, c)| c.min_width)
5387 .sum();
5388 let total_max_width: f32 = table_ctx
5389 .columns
5390 .iter()
5391 .enumerate()
5392 .filter(|(idx, _)| !table_ctx.collapsed_columns.contains(idx))
5393 .map(|(_, c)| c.max_width)
5394 .sum();
5395 let available_width = table_width; // Use table's content-box width, not constraints
5396
5397 debug_table_layout!(
5398 ctx,
5399 "calculate_column_widths_auto: min={:.2}, max={:.2}, table_width={:.2}",
5400 total_min_width,
5401 total_max_width,
5402 table_width
5403 );
5404
5405 // Handle infinity and NaN cases
5406 if !total_max_width.is_finite() || !available_width.is_finite() {
5407 // If max_width is infinite or unavailable, distribute available width equally
5408 let num_non_collapsed = table_ctx.columns.len() - table_ctx.collapsed_columns.len();
5409 let width_per_column = if num_non_collapsed > 0 {
5410 available_width / num_non_collapsed as f32
5411 } else {
5412 0.0
5413 };
5414
5415 for (col_idx, col) in table_ctx.columns.iter_mut().enumerate() {
5416 if table_ctx.collapsed_columns.contains(&col_idx) {
5417 col.computed_width = Some(0.0);
5418 } else {
5419 // Use the larger of min_width and equal distribution
5420 col.computed_width = Some(col.min_width.max(width_per_column));
5421 }
5422 }
5423 } else if available_width >= total_max_width {
5424 // Case 1: More space than max-content - distribute excess proportionally
5425 //
5426 // CSS 2.1 Section 17.5.2.2: Distribute extra space proportionally to
5427 // max-content widths
5428 let excess_width = available_width - total_max_width;
5429
5430 // First pass: collect column info (max_width) to avoid borrowing issues
5431 let column_info: Vec<(usize, f32, bool)> = table_ctx
5432 .columns
5433 .iter()
5434 .enumerate()
5435 .map(|(idx, c)| (idx, c.max_width, table_ctx.collapsed_columns.contains(&idx)))
5436 .collect();
5437
5438 // Calculate total weight for proportional distribution (use max_width as weight)
5439 let total_weight: f32 = column_info.iter()
5440 .filter(|(_, _, is_collapsed)| !is_collapsed)
5441 .map(|(_, max_w, _)| max_w.max(1.0)) // Avoid division by zero
5442 .sum();
5443
5444 let num_non_collapsed = column_info
5445 .iter()
5446 .filter(|(_, _, is_collapsed)| !is_collapsed)
5447 .count();
5448
5449 // Second pass: set computed widths
5450 for (col_idx, max_width, is_collapsed) in column_info {
5451 let col = &mut table_ctx.columns[col_idx];
5452 if is_collapsed {
5453 col.computed_width = Some(0.0);
5454 } else {
5455 // Start with max-content width, then add proportional share of excess
5456 let weight_factor = if total_weight > 0.0 {
5457 max_width.max(1.0) / total_weight
5458 } else {
5459 // If all columns have 0 max_width, distribute equally
5460 1.0 / num_non_collapsed.max(1) as f32
5461 };
5462
5463 let final_width = max_width + (excess_width * weight_factor);
5464 col.computed_width = Some(final_width);
5465 }
5466 }
5467 } else if available_width >= total_min_width {
5468 // Case 2: Between min and max - interpolate proportionally
5469 // Avoid division by zero if min == max
5470 let scale = if total_max_width > total_min_width {
5471 (available_width - total_min_width) / (total_max_width - total_min_width)
5472 } else {
5473 0.0 // If min == max, just use min width
5474 };
5475 for (col_idx, col) in table_ctx.columns.iter_mut().enumerate() {
5476 if table_ctx.collapsed_columns.contains(&col_idx) {
5477 col.computed_width = Some(0.0);
5478 } else {
5479 let interpolated = col.min_width + (col.max_width - col.min_width) * scale;
5480 col.computed_width = Some(interpolated);
5481 }
5482 }
5483 } else {
5484 // Case 3: Not enough space - scale down from min widths
5485 let scale = if total_min_width > 0.0 { available_width / total_min_width } else { 1.0 };
5486 for (col_idx, col) in table_ctx.columns.iter_mut().enumerate() {
5487 if table_ctx.collapsed_columns.contains(&col_idx) {
5488 col.computed_width = Some(0.0);
5489 } else {
5490 col.computed_width = Some(col.min_width * scale);
5491 }
5492 }
5493 }
5494
5495 Ok(())
5496}
5497
5498/// Distribute a multi-column cell's width across the columns it spans
5499fn distribute_cell_width_across_columns(
5500 columns: &mut [TableColumnInfo],
5501 start_col: usize,
5502 colspan: usize,
5503 cell_min_width: f32,
5504 cell_max_width: f32,
5505 collapsed_columns: &std::collections::HashSet<usize>,
5506) {
5507 let end_col = start_col + colspan;
5508 if end_col > columns.len() {
5509 return;
5510 }
5511
5512 // Calculate current total of spanned non-collapsed columns
5513 let current_min_total: f32 = columns[start_col..end_col]
5514 .iter()
5515 .enumerate()
5516 .filter(|(idx, _)| !collapsed_columns.contains(&(start_col + idx)))
5517 .map(|(_, c)| c.min_width)
5518 .sum();
5519 let current_max_total: f32 = columns[start_col..end_col]
5520 .iter()
5521 .enumerate()
5522 .filter(|(idx, _)| !collapsed_columns.contains(&(start_col + idx)))
5523 .map(|(_, c)| c.max_width)
5524 .sum();
5525
5526 // Count non-collapsed columns in the span
5527 let num_visible_cols = (start_col..end_col)
5528 .filter(|idx| !collapsed_columns.contains(idx))
5529 .count();
5530
5531 if num_visible_cols == 0 {
5532 return; // All spanned columns are collapsed
5533 }
5534
5535 // Only distribute if the cell needs more space than currently available
5536 if cell_min_width > current_min_total {
5537 let extra_min = cell_min_width - current_min_total;
5538 let per_col = extra_min / num_visible_cols as f32;
5539 for (idx, col) in columns[start_col..end_col].iter_mut().enumerate() {
5540 if !collapsed_columns.contains(&(start_col + idx)) {
5541 col.min_width += per_col;
5542 }
5543 }
5544 }
5545
5546 if cell_max_width > current_max_total {
5547 let extra_max = cell_max_width - current_max_total;
5548 let per_col = extra_max / num_visible_cols as f32;
5549 for (idx, col) in columns[start_col..end_col].iter_mut().enumerate() {
5550 if !collapsed_columns.contains(&(start_col + idx)) {
5551 col.max_width += per_col;
5552 }
5553 }
5554 }
5555}
5556
5557/// Layout a cell with its computed column width to determine its content height
5558fn layout_cell_for_height<T: ParsedFontTrait>(
5559 ctx: &mut LayoutContext<'_, T>,
5560 tree: &mut LayoutTree,
5561 text_cache: &mut crate::font_traits::TextLayoutCache,
5562 cell_index: usize,
5563 cell_width: f32,
5564 constraints: &LayoutConstraints,
5565) -> Result<f32> {
5566 let cell_node = tree.get(cell_index).ok_or(LayoutError::InvalidTree)?;
5567 let cell_dom_id = cell_node.dom_node_id.ok_or(LayoutError::InvalidTree)?;
5568
5569 // Check if cell has text content directly in DOM (not in LayoutTree)
5570 // Text nodes are intentionally not included in LayoutTree per CSS spec,
5571 // but we need to measure them for table cell height calculation.
5572 let has_text_children = cell_dom_id
5573 .az_children(&ctx.styled_dom.node_hierarchy.as_container())
5574 .any(|child_id| {
5575 let node_data = &ctx.styled_dom.node_data.as_container()[child_id];
5576 matches!(node_data.get_node_type(), NodeType::Text(_))
5577 });
5578
5579 debug_table_layout!(
5580 ctx,
5581 "layout_cell_for_height: cell_index={}, has_text_children={}",
5582 cell_index,
5583 has_text_children
5584 );
5585
5586 // Get padding and border to calculate content width
5587 let cell_node = tree.get(cell_index).ok_or(LayoutError::InvalidTree)?;
5588 let cell_bp = cell_node.box_props.unpack();
5589 let padding = &cell_bp.padding;
5590 let border = &cell_bp.border;
5591 let writing_mode = constraints.writing_mode;
5592
5593 // cell_width is the border-box width (includes padding/border from column
5594 // width calculation) but layout functions need content-box width
5595 let content_width = cell_width
5596 - padding.cross_start(writing_mode)
5597 - padding.cross_end(writing_mode)
5598 - border.cross_start(writing_mode)
5599 - border.cross_end(writing_mode);
5600
5601 debug_table_layout!(
5602 ctx,
5603 "Cell width: border_box={:.2}, content_box={:.2}",
5604 cell_width,
5605 content_width
5606 );
5607
5608 let content_height = if has_text_children {
5609 // Cell contains text - use IFC to measure it
5610 debug_table_layout!(ctx, "Using IFC to measure text content");
5611
5612 let cell_constraints = LayoutConstraints {
5613 available_size: LogicalSize {
5614 width: content_width, // Use content width, not border-box width
5615 height: f32::INFINITY,
5616 },
5617 writing_mode: constraints.writing_mode,
5618 writing_mode_ctx: constraints.writing_mode_ctx,
5619 bfc_state: None,
5620 text_align: constraints.text_align,
5621 containing_block_size: constraints.containing_block_size,
5622 // Use definite width for final cell layout!
5623 // This replaces any previous MinContent/MaxContent measurement.
5624 available_width_type: Text3AvailableSpace::Definite(content_width),
5625 };
5626
5627 let output = layout_ifc(ctx, text_cache, tree, cell_index, &cell_constraints)?;
5628
5629 // The cell now owns the authoritative IFC result. Clear any duplicate
5630 // inline_layout_result from text children that was set during the cell's
5631 // prior BFC Pass 1 (which ran before layout_cell_for_height).
5632 let cell_children: Vec<usize> = tree.children(cell_index).to_vec();
5633 for child_idx in cell_children {
5634 if let Some(warm) = tree.warm_mut(child_idx) {
5635 warm.inline_layout_result = None;
5636 }
5637 }
5638
5639 debug_table_layout!(
5640 ctx,
5641 "IFC returned height={:.2}",
5642 output.overflow_size.height
5643 );
5644
5645 output.overflow_size.height
5646 } else {
5647 // Cell contains block-level children or is empty - use regular layout
5648 debug_table_layout!(ctx, "Using regular layout for block children");
5649
5650 let cell_constraints = LayoutConstraints {
5651 available_size: LogicalSize {
5652 width: content_width, // Use content width, not border-box width
5653 height: f32::INFINITY,
5654 },
5655 writing_mode: constraints.writing_mode,
5656 writing_mode_ctx: constraints.writing_mode_ctx,
5657 bfc_state: None,
5658 text_align: constraints.text_align,
5659 containing_block_size: constraints.containing_block_size,
5660 // Use Definite width for final cell layout!
5661 available_width_type: Text3AvailableSpace::Definite(content_width),
5662 };
5663
5664 let mut temp_positions: super::PositionVec = Vec::new();
5665 let mut temp_scrollbar_reflow = false;
5666 let mut temp_float_cache = HashMap::new();
5667
5668 crate::solver3::cache::calculate_layout_for_subtree(
5669 ctx,
5670 tree,
5671 text_cache,
5672 cell_index,
5673 LogicalPosition::zero(),
5674 cell_constraints.available_size,
5675 &mut temp_positions,
5676 &mut temp_scrollbar_reflow,
5677 &mut temp_float_cache,
5678 // PerformLayout: final table cell layout with definite width
5679 crate::solver3::cache::ComputeMode::PerformLayout,
5680 )?;
5681
5682 let cell_node = tree.get(cell_index).ok_or(LayoutError::InvalidTree)?;
5683 cell_node.used_size.unwrap_or_default().height
5684 };
5685
5686 // Add padding and border to get the total height
5687 let cell_node = tree.get(cell_index).ok_or(LayoutError::InvalidTree)?;
5688 let cell_bp = cell_node.box_props.unpack();
5689 let padding = &cell_bp.padding;
5690 let border = &cell_bp.border;
5691 let writing_mode = constraints.writing_mode;
5692
5693 let total_height = content_height
5694 + padding.main_start(writing_mode)
5695 + padding.main_end(writing_mode)
5696 + border.main_start(writing_mode)
5697 + border.main_end(writing_mode);
5698
5699 debug_table_layout!(
5700 ctx,
5701 "Cell total height: cell_index={}, content={:.2}, padding/border={:.2}, total={:.2}",
5702 cell_index,
5703 content_height,
5704 padding.main_start(writing_mode)
5705 + padding.main_end(writing_mode)
5706 + border.main_start(writing_mode)
5707 + border.main_end(writing_mode),
5708 total_height
5709 );
5710
5711 Ok(total_height)
5712}
5713
5714// or bottom of content edge if no such line box exists
5715// +spec:box-model:b64fa0 - Cell baseline is first in-flow line box or bottom of content edge
5716// +spec:overflow:3fa86f - Table cell baseline: first in-flow line box or bottom of content edge; scrolling boxes treated as at origin
5717// +spec:inline-formatting-context:c4a20d - cell baseline: first in-flow line box or bottom of content edge
5718// +spec:inline-formatting-context:17a9c1 - vertical-align baseline/top/bottom/middle for table cells
5719fn compute_cell_baseline(cell_index: usize, tree: &LayoutTree) -> f32 {
5720 let Some(cell_node) = tree.get(cell_index) else {
5721 return 0.0;
5722 };
5723
5724 let cell_bp = cell_node.box_props.unpack();
5725
5726 // +spec:inline-formatting-context:27be38 - cell baseline is first in-flow line box or bottom of content edge
5727 // Check if the cell has inline layout (first in-flow line box)
5728 if let Some(warm_node) = tree.warm(cell_index) {
5729 if let Some(ref cached_layout) = warm_node.inline_layout_result {
5730 let inline_result = &cached_layout.layout;
5731 // The baseline is the ascent of the first item from the top of the cell
5732 if let Some(first_item) = inline_result.items.first() {
5733 let (item_ascent, _) = crate::text3::cache::get_item_vertical_metrics_approx(&first_item.item);
5734 let padding_top = cell_bp.padding.top;
5735 let border_top = cell_bp.border.top;
5736 return padding_top + border_top + first_item.position.y + item_ascent;
5737 }
5738 }
5739 }
5740
5741 // Check children for first in-flow line box
5742 let children = tree.children(cell_index);
5743 for &child_idx in children {
5744 if child_idx < tree.nodes.len() {
5745 if let Some(child_warm) = tree.warm(child_idx) {
5746 if child_warm.inline_layout_result.is_some() {
5747 let child_baseline = compute_cell_baseline(child_idx, tree);
5748 let padding_top = cell_bp.padding.top;
5749 let border_top = cell_bp.border.top;
5750 return padding_top + border_top + child_baseline;
5751 }
5752 }
5753 }
5754 }
5755
5756 // No line box found: baseline is the bottom of the content edge
5757 let used_size = cell_node.used_size.unwrap_or_default();
5758 let padding_bottom = cell_bp.padding.bottom;
5759 let border_bottom = cell_bp.border.bottom;
5760 used_size.height - padding_bottom - border_bottom
5761}
5762
5763/// +spec:box-model:72b495 - Table row height = max of computed height and MIN required by cells; baseline alignment
5764// +spec:display-property:728144 - Table height algorithm: row heights from cell content, rowspan distribution, vertical-align in cells (top/middle/bottom/baseline, sub/super/text-top/text-bottom/length/percentage fall back to baseline), cell baseline computation, and horizontal alignment via text-align
5765// +spec:positioning:3eaadd - Table height algorithms (§17.5.3): row height = max of cell heights/MIN,
5766// rowspan distribution, vertical-align in table cells, cell baseline definition
5767/// Calculate row heights based on cell content after column widths are determined
5768// +spec:inline-formatting-context:87b90d - Table height algorithms: row height = max(computed height, cell heights, MIN); vertical-align in cells (baseline/top/middle/bottom, sub/super/etc. fall back to baseline)
5769fn calculate_row_heights<T: ParsedFontTrait>(
5770 table_ctx: &mut TableLayoutContext,
5771 tree: &mut LayoutTree,
5772 text_cache: &mut crate::font_traits::TextLayoutCache,
5773 ctx: &mut LayoutContext<'_, T>,
5774 constraints: &LayoutConstraints,
5775) -> Result<()> {
5776 debug_table_layout!(
5777 ctx,
5778 "calculate_row_heights: num_rows={}, available_size={:?}",
5779 table_ctx.num_rows,
5780 constraints.available_size
5781 );
5782
5783 // +spec:inline-formatting-context:a7c7a0 - row height = max of computed height, cell heights, and MIN; vertical-align per cell
5784 // Initialize row heights and baselines
5785 table_ctx.row_heights = vec![0.0; table_ctx.num_rows];
5786 table_ctx.row_baselines = vec![0.0; table_ctx.num_rows];
5787
5788 // CSS 2.2 Section 17.6: Set collapsed rows to height 0
5789 for &row_idx in &table_ctx.collapsed_rows {
5790 if row_idx < table_ctx.row_heights.len() {
5791 table_ctx.row_heights[row_idx] = 0.0;
5792 }
5793 }
5794
5795 // required by content; 'height' property can influence row height but does not
5796 // increase cell box height
5797 // First pass: Calculate heights for cells that don't span multiple rows
5798 for cell_info in &table_ctx.cells {
5799 // Skip cells in collapsed rows
5800 if table_ctx.collapsed_rows.contains(&cell_info.row) {
5801 continue;
5802 }
5803
5804 // Get the cell's width (sum of column widths if colspan > 1)
5805 let mut cell_width = 0.0;
5806 for col_idx in cell_info.column..(cell_info.column + cell_info.colspan) {
5807 if let Some(col) = table_ctx.columns.get(col_idx) {
5808 if let Some(width) = col.computed_width {
5809 cell_width += width;
5810 }
5811 }
5812 }
5813
5814 debug_table_layout!(
5815 ctx,
5816 "Cell layout: node_index={}, row={}, col={}, width={:.2}",
5817 cell_info.node_index,
5818 cell_info.row,
5819 cell_info.column,
5820 cell_width
5821 );
5822
5823 // Layout the cell to get its height
5824 let cell_height = layout_cell_for_height(
5825 ctx,
5826 tree,
5827 text_cache,
5828 cell_info.node_index,
5829 cell_width,
5830 constraints,
5831 )?;
5832
5833 debug_table_layout!(
5834 ctx,
5835 "Cell height calculated: node_index={}, height={:.2}",
5836 cell_info.node_index,
5837 cell_height
5838 );
5839
5840 // row height = max of all single-span cell heights in the row
5841 if cell_info.rowspan == 1 {
5842 let current_height = table_ctx.row_heights[cell_info.row];
5843 table_ctx.row_heights[cell_info.row] = current_height.max(cell_height);
5844 }
5845
5846 // +spec:box-model:073652 - Table height: baseline-aligned cells establish row baseline, then top/bottom/middle cells positioned
5847 // The baseline of a cell is the baseline of its first line box (from inline layout)
5848 // or the bottom of the content box if no inline content.
5849 if cell_info.rowspan == 1 {
5850 let cell_baseline = compute_cell_baseline(cell_info.node_index, tree);
5851 let current_baseline = table_ctx.row_baselines[cell_info.row];
5852 table_ctx.row_baselines[cell_info.row] = current_baseline.max(cell_baseline);
5853 }
5854 }
5855
5856 // involved must be great enough to encompass the cell spanning the rows
5857 // Second pass: Handle cells that span multiple rows (rowspan > 1)
5858 for cell_info in &table_ctx.cells {
5859 // Skip cells that start in collapsed rows
5860 if table_ctx.collapsed_rows.contains(&cell_info.row) {
5861 continue;
5862 }
5863
5864 if cell_info.rowspan > 1 {
5865 // Get the cell's width
5866 let mut cell_width = 0.0;
5867 for col_idx in cell_info.column..(cell_info.column + cell_info.colspan) {
5868 if let Some(col) = table_ctx.columns.get(col_idx) {
5869 if let Some(width) = col.computed_width {
5870 cell_width += width;
5871 }
5872 }
5873 }
5874
5875 // Layout the cell to get its height
5876 let cell_height = layout_cell_for_height(
5877 ctx,
5878 tree,
5879 text_cache,
5880 cell_info.node_index,
5881 cell_width,
5882 constraints,
5883 )?;
5884
5885 // Calculate the current total height of spanned rows (excluding collapsed rows)
5886 let end_row = cell_info.row + cell_info.rowspan;
5887 let current_total: f32 = table_ctx.row_heights[cell_info.row..end_row]
5888 .iter()
5889 .enumerate()
5890 .filter(|(idx, _)| !table_ctx.collapsed_rows.contains(&(cell_info.row + idx)))
5891 .map(|(_, height)| height)
5892 .sum();
5893
5894 // If the cell needs more height, distribute extra height across
5895 // non-collapsed spanned rows
5896 if cell_height > current_total {
5897 let extra_height = cell_height - current_total;
5898
5899 // Count non-collapsed rows in span
5900 let non_collapsed_rows = (cell_info.row..end_row)
5901 .filter(|row_idx| !table_ctx.collapsed_rows.contains(row_idx))
5902 .count();
5903
5904 if non_collapsed_rows > 0 {
5905 let per_row = extra_height / non_collapsed_rows as f32;
5906
5907 for row_idx in cell_info.row..end_row {
5908 if !table_ctx.collapsed_rows.contains(&row_idx) {
5909 table_ctx.row_heights[row_idx] += per_row;
5910 }
5911 }
5912 }
5913 }
5914 }
5915 }
5916
5917 // CSS 2.2 Section 17.6: Final pass - ensure collapsed rows have height 0
5918 for &row_idx in &table_ctx.collapsed_rows {
5919 if row_idx < table_ctx.row_heights.len() {
5920 table_ctx.row_heights[row_idx] = 0.0;
5921 }
5922 }
5923
5924 // visible content, the row has zero height and v-spacing on only one side
5925 // +spec:table-layout:7370dc - empty-cells:hide in separated borders model
5926 // +spec:box-model:1e9cf1 - empty-cells:hide rows get zero height with v-spacing on only one side
5927 // +spec:overflow:a44925 - CSS 2.2 §17.6.1.1: empty-cells:hide suppresses borders/backgrounds; all-hidden rows get zero height
5928 // +spec:table-layout:dc8bc3 - separated borders model: border-spacing, empty-cells, row zero-height
5929 if table_ctx.border_collapse == StyleBorderCollapse::Separate {
5930 for row_idx in 0..table_ctx.num_rows {
5931 if table_ctx.collapsed_rows.contains(&row_idx) {
5932 continue;
5933 }
5934 // Collect cells in this row
5935 let row_cells: Vec<usize> = table_ctx
5936 .cells
5937 .iter()
5938 .filter(|c| c.row == row_idx && c.rowspan == 1)
5939 .map(|c| c.node_index)
5940 .collect();
5941 if row_cells.is_empty() {
5942 continue;
5943 }
5944 // +spec:box-model:0ab9b0 - empty-cells:hide suppresses borders/backgrounds, row gets zero height if all cells hidden+empty
5945 // Check if ALL cells in this row have empty-cells:hide and are empty
5946 let all_hidden_empty = row_cells.iter().all(|&cell_idx| {
5947 if let Some(cell_node) = tree.get(cell_idx) {
5948 let ec = get_empty_cells_property(ctx, cell_node);
5949 ec == StyleEmptyCells::Hide && is_cell_empty(tree, cell_idx)
5950 } else {
5951 true
5952 }
5953 });
5954 if all_hidden_empty {
5955 table_ctx.row_heights[row_idx] = 0.0;
5956 table_ctx.hidden_empty_rows.insert(row_idx);
5957 }
5958 }
5959 }
5960
5961 Ok(())
5962}
5963
5964/// Position all cells in the table grid with calculated widths and heights
5965fn position_table_cells<T: ParsedFontTrait>(
5966 table_ctx: &mut TableLayoutContext,
5967 tree: &mut LayoutTree,
5968 ctx: &mut LayoutContext<'_, T>,
5969 table_index: usize,
5970 constraints: &LayoutConstraints,
5971) -> Result<BTreeMap<usize, LogicalPosition>> {
5972 debug_log!(ctx, "Positioning table cells in grid");
5973
5974 let mut positions = BTreeMap::new();
5975
5976 // +spec:box-model:54e86a - Separated borders model: individual cell borders, border-spacing between cells, empty-cells handling
5977 // rows, columns, row groups, column groups cannot have borders (UA must ignore border props);
5978 // row/column/rowgroup/colgroup backgrounds are invisible in border-spacing area (table bg shows through);
5979 // distance from table edge to edge-cell border = table padding + border-spacing
5980 // (table padding is already accounted for by the containing block; h_spacing is the border-spacing)
5981 // Get border spacing values if border-collapse is separate
5982 let (h_spacing, v_spacing) = if table_ctx.border_collapse == StyleBorderCollapse::Separate {
5983 let styled_dom = ctx.styled_dom;
5984 let table_id = tree.nodes[table_index].dom_node_id.unwrap();
5985 let table_state = &styled_dom.styled_nodes.as_container()[table_id].styled_node_state;
5986
5987 let spacing_context = ResolutionContext {
5988 element_font_size: get_element_font_size(styled_dom, table_id, table_state),
5989 parent_font_size: get_parent_font_size(styled_dom, table_id, table_state),
5990 root_font_size: get_root_font_size(styled_dom, table_state),
5991 containing_block_size: PhysicalSize::new(0.0, 0.0),
5992 element_size: None,
5993 viewport_size: PhysicalSize::new(ctx.viewport_size.width, ctx.viewport_size.height),
5994 };
5995
5996 let h = table_ctx
5997 .border_spacing
5998 .horizontal
5999 .resolve_with_context(&spacing_context, PropertyContext::Other)
6000 .max(0.0);
6001
6002 let v = table_ctx
6003 .border_spacing
6004 .vertical
6005 .resolve_with_context(&spacing_context, PropertyContext::Other)
6006 .max(0.0);
6007
6008 (h, v)
6009 } else {
6010 (0.0, 0.0)
6011 };
6012
6013 debug_log!(
6014 ctx,
6015 "Border spacing: h={:.2}, v={:.2}",
6016 h_spacing,
6017 v_spacing
6018 );
6019
6020 // Calculate cumulative column positions (x-offsets) with spacing
6021 let mut col_positions = vec![0.0; table_ctx.columns.len()];
6022 let mut x_offset = h_spacing; // Start with spacing on the left
6023 for (i, col) in table_ctx.columns.iter().enumerate() {
6024 col_positions[i] = x_offset;
6025 if let Some(width) = col.computed_width {
6026 // Collapsed columns: gutters on either side collapse (width is 0, skip spacing)
6027 if table_ctx.collapsed_columns.contains(&i) {
6028 // No width, no gutter added
6029 } else {
6030 x_offset += width + h_spacing; // Add spacing between columns
6031 }
6032 }
6033 }
6034
6035 // Calculate cumulative row positions (y-offsets) with spacing
6036 let mut row_positions = vec![0.0; table_ctx.num_rows];
6037 let mut y_offset = v_spacing; // Start with spacing on the top
6038 for (i, &height) in table_ctx.row_heights.iter().enumerate() {
6039 row_positions[i] = y_offset;
6040 // Collapsed rows: gutters on either side collapse (height is 0, skip spacing)
6041 if table_ctx.collapsed_rows.contains(&i) {
6042 // No height, no gutter added
6043 } else if table_ctx.hidden_empty_rows.contains(&i) {
6044 // Hidden-empty row: zero height, only one side of spacing
6045 // (we already added spacing before this row, so skip the spacing after)
6046 y_offset += height; // height is 0.0
6047 } else {
6048 y_offset += height + v_spacing; // Add spacing between rows
6049 }
6050 }
6051
6052 // Store row positions and sizes so paint_element_background can paint row backgrounds.
6053 // Row width = sum of column widths + spacing. Row height from row_heights.
6054 {
6055 let total_col_width: f32 = table_ctx.columns.iter().map(|c| c.computed_width.unwrap_or(0.0)).sum::<f32>()
6056 + h_spacing * (table_ctx.columns.len().max(1) - 1) as f32
6057 + h_spacing * 2.0; // border-spacing on left+right edges
6058 for (i, &row_y) in row_positions.iter().enumerate() {
6059 if let Some(&row_node_idx) = table_ctx.row_node_indices.get(i) {
6060 let row_height = table_ctx.row_heights.get(i).copied().unwrap_or(0.0);
6061 if let Some(row_node) = tree.get_mut(row_node_idx) {
6062 row_node.used_size = Some(LogicalSize {
6063 width: total_col_width,
6064 height: row_height,
6065 });
6066 }
6067 // Don't add to `positions` map (feeds position_bfc_child_descendants,
6068 // would double-offset cells). The display list computes row paint
6069 // rects from the row's cell children.
6070 }
6071 }
6072 }
6073
6074 // Position each cell
6075 for cell_info in &table_ctx.cells {
6076 let precomputed_cell_baseline = compute_cell_baseline(cell_info.node_index, tree);
6077
6078 let cell_node = tree
6079 .get_mut(cell_info.node_index)
6080 .ok_or(LayoutError::InvalidTree)?;
6081
6082 // Calculate cell position
6083 let x = col_positions.get(cell_info.column).copied().unwrap_or(0.0);
6084 let y = row_positions.get(cell_info.row).copied().unwrap_or(0.0);
6085
6086 // Calculate cell size (sum of spanned columns/rows)
6087 let mut width = 0.0;
6088 debug_info!(
6089 ctx,
6090 "[position_table_cells] Cell {}: calculating width from cols {}..{}",
6091 cell_info.node_index,
6092 cell_info.column,
6093 cell_info.column + cell_info.colspan
6094 );
6095 for col_idx in cell_info.column..(cell_info.column + cell_info.colspan) {
6096 if let Some(col) = table_ctx.columns.get(col_idx) {
6097 debug_info!(
6098 ctx,
6099 "[position_table_cells] Col {}: computed_width={:?}",
6100 col_idx,
6101 col.computed_width
6102 );
6103 if let Some(col_width) = col.computed_width {
6104 width += col_width;
6105 // Add spacing between spanned columns (but not after the last one)
6106 if col_idx < cell_info.column + cell_info.colspan - 1 {
6107 width += h_spacing;
6108 }
6109 } else {
6110 debug_info!(
6111 ctx,
6112 "[position_table_cells] WARN: Col {} has NO computed_width!",
6113 col_idx
6114 );
6115 }
6116 } else {
6117 debug_info!(
6118 ctx,
6119 "[position_table_cells] WARN: Col {} not found in table_ctx.columns!",
6120 col_idx
6121 );
6122 }
6123 }
6124
6125 let mut height = 0.0;
6126 let end_row = cell_info.row + cell_info.rowspan;
6127 for row_idx in cell_info.row..end_row {
6128 if let Some(&row_height) = table_ctx.row_heights.get(row_idx) {
6129 height += row_height;
6130 // Add spacing between spanned rows (but not after the last one)
6131 if row_idx < end_row - 1 {
6132 height += v_spacing;
6133 }
6134 }
6135 }
6136
6137 // Update cell's used size and position
6138 let writing_mode = constraints.writing_mode;
6139 // Table layout works in main/cross axes, must convert back to logical width/height
6140
6141 debug_info!(
6142 ctx,
6143 "[position_table_cells] Cell {}: BEFORE from_main_cross: width={}, height={}, \
6144 writing_mode={:?}",
6145 cell_info.node_index,
6146 width,
6147 height,
6148 writing_mode
6149 );
6150
6151 cell_node.used_size = Some(LogicalSize::from_main_cross(height, width, writing_mode));
6152
6153 debug_info!(
6154 ctx,
6155 "[position_table_cells] Cell {}: AFTER from_main_cross: used_size={:?}",
6156 cell_info.node_index,
6157 cell_node.used_size
6158 );
6159
6160 debug_info!(
6161 ctx,
6162 "[position_table_cells] Cell {}: setting used_size to {}x{} (row_heights={:?})",
6163 cell_info.node_index,
6164 width,
6165 height,
6166 table_ctx.row_heights
6167 );
6168
6169 // Save hot fields needed for vertical alignment before dropping the mutable borrow
6170 let cell_dom_node_id = cell_node.dom_node_id;
6171 let cell_box_props = cell_node.box_props.unpack();
6172 drop(cell_node);
6173
6174 // +spec:inline-formatting-context:20e8e8 - table cell vertical-align alignment order (baseline first, then top, then bottom/middle)
6175 // receive extra top or bottom padding; vertical-align determines alignment
6176 // +spec:inline-formatting-context:4545e8 - vertical-align on table cells maps to align-content: top→start, bottom→end, middle→center
6177 // +spec:inline-formatting-context:e216be - vertical-align on table cells (baseline, middle, top, bottom)
6178 // +spec:positioning:156e49 - table cell vertical-align ordering and extra padding per CSS 2.2 §17.5.3
6179 // Apply vertical-align to cell content if it has inline layout
6180 // We need to compute the y_offset using immutable borrows first, then apply it mutably.
6181 let vertical_align_adjustment = if let Some(warm_node) = tree.warm(cell_info.node_index) {
6182 if let Some(ref cached_layout) = warm_node.inline_layout_result {
6183 let inline_result = &cached_layout.layout;
6184 use StyleVerticalAlign;
6185
6186 // Get vertical-align property from styled_dom
6187 let vertical_align = if let Some(dom_id) = cell_dom_node_id {
6188 let node_state = ctx.styled_dom.styled_nodes.as_container()[dom_id].styled_node_state.clone();
6189
6190 match get_vertical_align_property(ctx.styled_dom, dom_id, &node_state) {
6191 MultiValue::Exact(v) => v,
6192 _ => StyleVerticalAlign::Baseline,
6193 }
6194 } else {
6195 StyleVerticalAlign::Baseline
6196 };
6197
6198 // Calculate content height from inline layout bounds
6199 let content_bounds = inline_result.bounds();
6200 let content_height = content_bounds.height;
6201
6202 // Get padding and border to calculate content-box height
6203 // height is border-box, but vertical alignment should be within content-box
6204 let padding = &cell_box_props.padding;
6205 let border = &cell_box_props.border;
6206 let content_box_height = height
6207 - padding.main_start(writing_mode)
6208 - padding.main_end(writing_mode)
6209 - border.main_start(writing_mode)
6210 - border.main_end(writing_mode);
6211
6212 // top: top of cell box aligned with top of first row it spans
6213 // bottom: bottom of cell box aligned with bottom of last row it spans
6214 // middle: center of cell aligned with center of rows it spans
6215 // the cell is aligned at the baseline instead
6216 let y_offset = match vertical_align {
6217 StyleVerticalAlign::Top => 0.0,
6218 StyleVerticalAlign::Middle => (content_box_height - content_height) * 0.5,
6219 StyleVerticalAlign::Bottom => content_box_height - content_height,
6220 // align with the row baseline. cell_baseline = distance from top of cell box
6221 // to cell's baseline; row_baseline = distance from top of row to row's baseline
6222 StyleVerticalAlign::Baseline
6223 | StyleVerticalAlign::Sub
6224 | StyleVerticalAlign::Superscript
6225 | StyleVerticalAlign::TextTop
6226 | StyleVerticalAlign::TextBottom
6227 | StyleVerticalAlign::Percentage(_)
6228 | StyleVerticalAlign::Length(_) => {
6229 let row_baseline = table_ctx.row_baselines.get(cell_info.row).copied().unwrap_or(0.0);
6230 (row_baseline - precomputed_cell_baseline).max(0.0)
6231 }
6232 };
6233
6234 debug_info!(
6235 ctx,
6236 "[position_table_cells] Cell {}: vertical-align={:?}, border_box_height={}, \
6237 content_box_height={}, content_height={}, y_offset={}",
6238 cell_info.node_index,
6239 vertical_align,
6240 height,
6241 content_box_height,
6242 content_height,
6243 y_offset
6244 );
6245
6246 if y_offset.abs() > 0.01 {
6247 Some((y_offset, cached_layout.available_width, cached_layout.has_floats))
6248 } else {
6249 None
6250 }
6251 } else {
6252 None
6253 }
6254 } else {
6255 None
6256 };
6257
6258 // Apply the vertical alignment adjustment (requires mutable borrow)
6259 if let Some((y_offset, available_width, has_floats)) = vertical_align_adjustment {
6260 if let Some(warm_mut) = tree.warm_mut(cell_info.node_index) {
6261 if let Some(ref cached_layout) = warm_mut.inline_layout_result {
6262 use std::sync::Arc;
6263 use crate::text3::cache::{PositionedItem, UnifiedLayout};
6264
6265 let adjusted_items: Vec<PositionedItem> = cached_layout.layout
6266 .items
6267 .iter()
6268 .map(|item| PositionedItem {
6269 item: item.item.clone(),
6270 position: crate::text3::cache::Point {
6271 x: item.position.x,
6272 y: item.position.y + y_offset,
6273 },
6274 line_index: item.line_index,
6275 })
6276 .collect();
6277
6278 let adjusted_layout = UnifiedLayout {
6279 items: adjusted_items,
6280 overflow: cached_layout.layout.overflow.clone(),
6281 };
6282
6283 // Keep the same constraint type from the cached layout
6284 warm_mut.inline_layout_result = Some(CachedInlineLayout::new(
6285 Arc::new(adjusted_layout),
6286 available_width,
6287 has_floats,
6288 ));
6289 }
6290 }
6291 }
6292
6293 // Store position relative to table origin
6294 let position = LogicalPosition::from_main_cross(y, x, writing_mode);
6295
6296 // Insert position into map so cache module can position the cell
6297 positions.insert(cell_info.node_index, position);
6298
6299 debug_log!(
6300 ctx,
6301 "Cell at row={}, col={}: pos=({:.2}, {:.2}), size=({:.2}x{:.2})",
6302 cell_info.row,
6303 cell_info.column,
6304 x,
6305 y,
6306 width,
6307 height
6308 );
6309 }
6310
6311 Ok(positions)
6312}
6313
6314/// Gathers all inline content for `text3`, recursively laying out `inline-block` children
6315/// to determine their size and baseline before passing them to the text engine.
6316///
6317/// This function also assigns IFC membership to all participating nodes:
6318/// - The IFC root gets an `ifc_id` assigned
6319/// - Each text/inline child gets `ifc_membership` set with a reference back to the IFC root
6320///
6321/// This mapping enables efficient cursor hit-testing: when a text node is clicked,
6322/// we can find its parent IFC's `inline_layout_result` via `ifc_membership.ifc_root_layout_index`.
6323// +spec:display-property:63a38b - inline box boundaries and out-of-flow elements are ignored for text adjacency (white space, line-breaking, text-transform)
6324fn collect_and_measure_inline_content<T: ParsedFontTrait>(
6325 ctx: &mut LayoutContext<'_, T>,
6326 text_cache: &mut TextLayoutCache,
6327 tree: &mut LayoutTree,
6328 ifc_root_index: usize,
6329 constraints: &LayoutConstraints,
6330) -> Result<(Vec<InlineContent>, HashMap<ContentIndex, usize>)> {
6331 use crate::solver3::layout_tree::{IfcId, IfcMembership};
6332 use crate::text3::cache::InlineContent;
6333
6334 let result = collect_and_measure_inline_content_impl(ctx, text_cache, tree, ifc_root_index, constraints)?;
6335 Ok(result)
6336}
6337
6338fn collect_and_measure_inline_content_impl<T: ParsedFontTrait>(
6339 ctx: &mut LayoutContext<'_, T>,
6340 text_cache: &mut TextLayoutCache,
6341 tree: &mut LayoutTree,
6342 ifc_root_index: usize,
6343 constraints: &LayoutConstraints,
6344) -> Result<(Vec<InlineContent>, HashMap<ContentIndex, usize>)> {
6345 use crate::solver3::layout_tree::{IfcId, IfcMembership};
6346
6347 debug_ifc_layout!(
6348 ctx,
6349 "collect_and_measure_inline_content: node_index={}",
6350 ifc_root_index
6351 );
6352
6353 // Generate a unique IFC ID for this inline formatting context
6354 let ifc_id = IfcId::unique();
6355
6356 // Store IFC ID on the IFC root node
6357 if let Some(cold_node) = tree.cold_mut(ifc_root_index) {
6358 cold_node.ifc_id = Some(ifc_id);
6359 }
6360
6361 let mut content = Vec::new();
6362 // Maps the `ContentIndex` used by text3 back to the `LayoutNode` index.
6363 let mut child_map = HashMap::new();
6364 // Track the current run index for IFC membership assignment
6365 let mut current_run_index: u32 = 0;
6366
6367 let ifc_root_node = tree.get(ifc_root_index).ok_or(LayoutError::InvalidTree)?;
6368
6369 // Check if this is an anonymous IFC wrapper (has no DOM ID)
6370 let is_anonymous = ifc_root_node.dom_node_id.is_none();
6371
6372 // Get the DOM node ID of the IFC root, or find it from parent/children for anonymous boxes
6373 // CSS 2.2 § 9.2.1.1: Anonymous boxes inherit properties from their enclosing box
6374 let ifc_root_dom_id = match ifc_root_node.dom_node_id {
6375 Some(id) => id,
6376 None => {
6377 // Anonymous box - get DOM ID from parent or first child with DOM ID
6378 let parent_dom_id = ifc_root_node
6379 .parent
6380 .and_then(|p| tree.get(p))
6381 .and_then(|n| n.dom_node_id);
6382
6383 if let Some(id) = parent_dom_id {
6384 id
6385 } else {
6386 // Try to find DOM ID from first child
6387 match tree.children(ifc_root_index)
6388 .iter()
6389 .filter_map(|&child_idx| tree.get(child_idx))
6390 .filter_map(|n| n.dom_node_id)
6391 .next()
6392 {
6393 Some(id) => id,
6394 None => {
6395 debug_warning!(ctx, "IFC root and all ancestors/children have no DOM ID");
6396 return Ok((content, child_map));
6397 }
6398 }
6399 }
6400 }
6401 };
6402
6403 // Collect children to avoid holding an immutable borrow during iteration
6404 let children: Vec<_> = tree.children(ifc_root_index).to_vec();
6405 drop(ifc_root_node);
6406
6407 debug_ifc_layout!(
6408 ctx,
6409 "Node {} has {} layout children, is_anonymous={}",
6410 ifc_root_index,
6411 children.len(),
6412 is_anonymous
6413 );
6414
6415 // For anonymous IFC wrappers, we collect content from layout tree children
6416 // For regular IFC roots, we also check DOM children for text nodes
6417 if is_anonymous {
6418 // Anonymous IFC wrapper - iterate over layout tree children and collect their content
6419 for (item_idx, &child_index) in children.iter().enumerate() {
6420 let content_index = ContentIndex {
6421 run_index: ifc_root_index as u32,
6422 item_index: item_idx as u32,
6423 };
6424
6425 let child_node = tree.get(child_index).ok_or(LayoutError::InvalidTree)?;
6426 let Some(dom_id) = child_node.dom_node_id else {
6427 debug_warning!(
6428 ctx,
6429 "Anonymous IFC child at index {} has no DOM ID",
6430 child_index
6431 );
6432 continue;
6433 };
6434
6435 let node_data = &ctx.styled_dom.node_data.as_container()[dom_id];
6436
6437 // Check if this is a text node
6438 if let NodeType::Text(ref text_content) = node_data.get_node_type() {
6439 debug_info!(
6440 ctx,
6441 "[collect_and_measure_inline_content] OK: Found text node (DOM {:?}) in anonymous wrapper: '{}'",
6442 dom_id,
6443 text_content.as_str()
6444 );
6445 // Get style from the TEXT NODE itself (dom_id), not the IFC root
6446 // This ensures inline styles like color: #666666 are applied to the text
6447 let style = Arc::new(get_style_properties(ctx.styled_dom, dom_id, ctx.system_style.as_ref(), PhysicalSize::new(ctx.viewport_size.width, ctx.viewport_size.height)));
6448 let text_items = split_text_for_whitespace(
6449 ctx.styled_dom,
6450 dom_id,
6451 text_content.as_str(),
6452 style,
6453 );
6454 content.extend(text_items);
6455 child_map.insert(content_index, child_index);
6456
6457 // Set IFC membership on the text node - drop child_node borrow first
6458 drop(child_node);
6459 if let Some(warm_mut) = tree.warm_mut(child_index) {
6460 warm_mut.ifc_membership = Some(IfcMembership {
6461 ifc_id,
6462 ifc_root_layout_index: ifc_root_index,
6463 run_index: current_run_index,
6464 });
6465 }
6466 current_run_index += 1;
6467
6468 continue;
6469 }
6470
6471 // Non-text inline child - add as shape for inline-block
6472 let display = get_display_property(ctx.styled_dom, Some(dom_id)).unwrap_or_default();
6473
6474 if display != LayoutDisplay::Inline {
6475 // +spec:display-property:a37a9a - atomic inline-level boxes treated as neutral characters in bidi reordering
6476 // This is an atomic inline-level box (e.g., inline-block, image).
6477 // We must determine its size and baseline before passing it to text3.
6478
6479 // The intrinsic sizing pass has already calculated its preferred size.
6480 let intrinsic_size = tree.warm(child_index).and_then(|w| w.intrinsic_sizes.clone()).unwrap_or_default();
6481 let box_props = child_node.box_props.unpack();
6482
6483 let styled_node_state = ctx
6484 .styled_dom
6485 .styled_nodes
6486 .as_container()
6487 .get(dom_id)
6488 .map(|n| n.styled_node_state.clone())
6489 .unwrap_or_default();
6490
6491 // Calculate tentative border-box size based on CSS properties
6492 let tentative_size = crate::solver3::sizing::calculate_used_size_for_node(
6493 ctx.styled_dom,
6494 Some(dom_id),
6495 constraints.containing_block_size,
6496 intrinsic_size,
6497 &box_props,
6498 ctx.viewport_size,
6499 )?;
6500
6501 let writing_mode = get_writing_mode(ctx.styled_dom, dom_id, &styled_node_state)
6502 .unwrap_or_default();
6503
6504 // Determine content-box size for laying out children
6505 let content_box_size = box_props.inner_size(tentative_size, writing_mode);
6506
6507 // To find its height and baseline, we must lay out its contents.
6508 let child_wm_ctx = super::geometry::WritingModeContext::new(
6509 writing_mode,
6510 get_direction_property(ctx.styled_dom, dom_id, &styled_node_state)
6511 .unwrap_or_default(),
6512 get_text_orientation_property(ctx.styled_dom, dom_id, &styled_node_state)
6513 .unwrap_or_default(),
6514 );
6515 let child_constraints = LayoutConstraints {
6516 available_size: LogicalSize::new(content_box_size.width, f32::INFINITY),
6517 writing_mode,
6518 writing_mode_ctx: child_wm_ctx,
6519 bfc_state: None,
6520 text_align: TextAlign::Start,
6521 containing_block_size: constraints.containing_block_size,
6522 available_width_type: Text3AvailableSpace::Definite(content_box_size.width),
6523 };
6524
6525 // Drop the immutable borrow before calling layout_formatting_context
6526 drop(child_node);
6527
6528 // Recursively lay out the inline-block to get its final height and baseline.
6529 let mut empty_float_cache = HashMap::new();
6530 let layout_result = layout_formatting_context(
6531 ctx,
6532 tree,
6533 text_cache,
6534 child_index,
6535 &child_constraints,
6536 &mut empty_float_cache,
6537 )?;
6538
6539 let css_height = get_css_height(ctx.styled_dom, dom_id, &styled_node_state);
6540
6541 // Determine final border-box height
6542 let final_height = match css_height.unwrap_or_default() {
6543 LayoutHeight::Auto => {
6544 let content_height = layout_result.output.overflow_size.height;
6545 content_height
6546 + box_props.padding.main_sum(writing_mode)
6547 + box_props.border.main_sum(writing_mode)
6548 }
6549 _ => tentative_size.height,
6550 };
6551
6552 let final_size = LogicalSize::new(tentative_size.width, final_height);
6553
6554 // Update the node in the tree with its now-known used size.
6555 tree.get_mut(child_index).unwrap().used_size = Some(final_size);
6556
6557 // CSS 2.2 § 10.8.1: inline-block baseline fallback
6558 // If overflow is not 'visible', use bottom margin edge as baseline
6559 let overflow_x = get_overflow_x(ctx.styled_dom, dom_id, &styled_node_state).unwrap_or_default();
6560 let overflow_y = get_overflow_y(ctx.styled_dom, dom_id, &styled_node_state).unwrap_or_default();
6561 let overflow_is_visible = matches!(
6562 (overflow_x, overflow_y),
6563 (LayoutOverflow::Visible, LayoutOverflow::Visible)
6564 );
6565 let baseline_offset = if overflow_is_visible {
6566 layout_result.output.baseline.unwrap_or(final_height)
6567 } else {
6568 final_height
6569 };
6570
6571 // +spec:box-model:66ad24 - inline-axis margins, borders, padding respected for inline-level boxes (no collapsing)
6572 // The margin-box size is used so text3 positions inline-blocks with proper spacing
6573 let margin = &box_props.margin;
6574 let margin_box_width = final_size.width + margin.left + margin.right;
6575 let margin_box_height = final_size.height + margin.top + margin.bottom;
6576
6577 // For inline-block shapes, text3 uses the content array index as run_index
6578 // and always item_index=0 for objects. We must match this when inserting into child_map.
6579 let shape_content_index = ContentIndex {
6580 run_index: content.len() as u32,
6581 item_index: 0,
6582 };
6583 content.push(InlineContent::Shape(InlineShape {
6584 shape_def: ShapeDefinition::Rectangle {
6585 size: crate::text3::cache::Size {
6586 // Use margin-box size for positioning in inline flow
6587 width: margin_box_width,
6588 height: margin_box_height,
6589 },
6590 corner_radius: None,
6591 },
6592 fill: None,
6593 stroke: None,
6594 // Adjust baseline offset by top margin
6595 baseline_offset: baseline_offset + margin.top,
6596 alignment: crate::solver3::getters::get_vertical_align_for_node(ctx.styled_dom, dom_id),
6597 source_node_id: Some(dom_id),
6598 }));
6599 child_map.insert(shape_content_index, child_index);
6600 } else {
6601 // Regular inline element - collect its text children
6602 let span_style = get_style_properties(ctx.styled_dom, dom_id, ctx.system_style.as_ref(), PhysicalSize::new(ctx.viewport_size.width, ctx.viewport_size.height));
6603 collect_inline_span_recursive(
6604 ctx,
6605 tree,
6606 dom_id,
6607 span_style,
6608 &mut content,
6609 &mut child_map,
6610 &children,
6611 constraints,
6612 )?;
6613 }
6614 }
6615
6616 return Ok((content, child_map));
6617 }
6618
6619 // Regular (non-anonymous) IFC root - check for list markers and use DOM traversal
6620
6621 // Check if this IFC root OR its parent is a list-item and needs a marker
6622 // Case 1: IFC root itself is list-item (e.g., <li> with display: list-item)
6623 // Case 2: IFC root's parent is list-item (e.g., <li><text>...</text></li>)
6624 let ifc_root_node = tree.get(ifc_root_index).ok_or(LayoutError::InvalidTree)?;
6625 let mut list_item_dom_id: Option<NodeId> = None;
6626
6627 // Check IFC root itself
6628 if let Some(dom_id) = ifc_root_node.dom_node_id {
6629 use crate::solver3::getters::get_display_property;
6630 if let MultiValue::Exact(display) = get_display_property(ctx.styled_dom, Some(dom_id)) {
6631 use LayoutDisplay;
6632 if display == LayoutDisplay::ListItem {
6633 debug_ifc_layout!(ctx, "IFC root NodeId({:?}) is list-item", dom_id);
6634 list_item_dom_id = Some(dom_id);
6635 }
6636 }
6637 }
6638
6639 // Check IFC root's parent
6640 if list_item_dom_id.is_none() {
6641 if let Some(parent_idx) = ifc_root_node.parent {
6642 if let Some(parent_node) = tree.get(parent_idx) {
6643 if let Some(parent_dom_id) = parent_node.dom_node_id {
6644 use crate::solver3::getters::get_display_property;
6645 if let MultiValue::Exact(display) = get_display_property(ctx.styled_dom, Some(parent_dom_id)) {
6646 use LayoutDisplay;
6647 if display == LayoutDisplay::ListItem {
6648 debug_ifc_layout!(
6649 ctx,
6650 "IFC root parent NodeId({:?}) is list-item",
6651 parent_dom_id
6652 );
6653 list_item_dom_id = Some(parent_dom_id);
6654 }
6655 }
6656 }
6657 }
6658 }
6659 }
6660
6661 // If we found a list-item, generate markers
6662 if let Some(list_dom_id) = list_item_dom_id {
6663 debug_ifc_layout!(
6664 ctx,
6665 "Found list-item (NodeId({:?})), generating marker",
6666 list_dom_id
6667 );
6668
6669 // Find the layout node index for the list-item DOM node
6670 let list_item_layout_idx = tree
6671 .nodes
6672 .iter()
6673 .enumerate()
6674 .find(|(idx, node)| {
6675 node.dom_node_id == Some(list_dom_id) && tree.warm(*idx).and_then(|w| w.pseudo_element).is_none()
6676 })
6677 .map(|(idx, _)| idx);
6678
6679 if let Some(list_idx) = list_item_layout_idx {
6680 // Per CSS spec, the ::marker pseudo-element is the first child of the list-item
6681 // Find the ::marker pseudo-element in the list-item's children
6682 let marker_idx = tree.children(list_idx)
6683 .iter()
6684 .find(|&&child_idx| {
6685 tree.warm(child_idx)
6686 .map(|w| w.pseudo_element == Some(PseudoElement::Marker))
6687 .unwrap_or(false)
6688 })
6689 .copied();
6690
6691 if let Some(marker_idx) = marker_idx {
6692 debug_ifc_layout!(ctx, "Found ::marker pseudo-element at index {}", marker_idx);
6693
6694 // Get the DOM ID for style resolution (marker references the same DOM node as
6695 // list-item)
6696 let list_dom_id_for_style = tree
6697 .get(marker_idx)
6698 .and_then(|n| n.dom_node_id)
6699 .unwrap_or(list_dom_id);
6700
6701 // Get list-style-position to determine marker positioning
6702 // Default is 'outside' per CSS Lists Module Level 3
6703
6704 let list_style_position =
6705 get_list_style_position(ctx.styled_dom, Some(list_dom_id));
6706 let position_outside =
6707 matches!(list_style_position, StyleListStylePosition::Outside);
6708
6709 debug_ifc_layout!(
6710 ctx,
6711 "List marker list-style-position: {:?} (outside={})",
6712 list_style_position,
6713 position_outside
6714 );
6715
6716 // Generate marker text segments - font fallback happens during shaping
6717 let base_style =
6718 Arc::new(get_style_properties(ctx.styled_dom, list_dom_id_for_style, ctx.system_style.as_ref(), PhysicalSize::new(ctx.viewport_size.width, ctx.viewport_size.height)));
6719 let marker_segments = generate_list_marker_segments(
6720 tree,
6721 ctx.styled_dom,
6722 marker_idx, // Pass the marker index, not the list-item index
6723 ctx.counters,
6724 base_style,
6725 ctx.debug_messages,
6726 );
6727
6728 debug_ifc_layout!(
6729 ctx,
6730 "Generated {} list marker segments",
6731 marker_segments.len()
6732 );
6733
6734 // Add markers as InlineContent::Marker with position information
6735 // Outside markers will be positioned in the padding gutter by the layout engine
6736 for segment in marker_segments {
6737 content.push(InlineContent::Marker {
6738 run: segment,
6739 position_outside,
6740 });
6741 }
6742 } else {
6743 debug_ifc_layout!(
6744 ctx,
6745 "WARNING: List-item at index {} has no ::marker pseudo-element",
6746 list_idx
6747 );
6748 }
6749 }
6750 }
6751
6752 drop(ifc_root_node);
6753
6754 // IMPORTANT: We need to traverse the DOM, not just the layout tree!
6755 //
6756 // According to CSS spec, a block container with inline-level children establishes
6757 // an IFC and should collect ALL inline content, including text nodes.
6758 // Text nodes exist in the DOM but might not have their own layout tree nodes.
6759
6760 // Debug: Check what the node_hierarchy says about this node
6761 let node_hier_item = &ctx.styled_dom.node_hierarchy.as_container()[ifc_root_dom_id];
6762 debug_info!(
6763 ctx,
6764 "[collect_and_measure_inline_content] DEBUG: node_hier_item.first_child={:?}, \
6765 last_child={:?}",
6766 node_hier_item.first_child_id(ifc_root_dom_id),
6767 node_hier_item.last_child_id()
6768 );
6769
6770 let dom_children: Vec<NodeId> = ifc_root_dom_id
6771 .az_children(&ctx.styled_dom.node_hierarchy.as_container())
6772 .collect();
6773
6774 let ifc_root_node_data = &ctx.styled_dom.node_data.as_container()[ifc_root_dom_id];
6775
6776 // SPECIAL CASE: If the IFC root itself is a text node (leaf node),
6777 // add its text content directly instead of iterating over children
6778 if let NodeType::Text(ref text_content) = ifc_root_node_data.get_node_type() {
6779 let style = Arc::new(get_style_properties(ctx.styled_dom, ifc_root_dom_id, ctx.system_style.as_ref(), PhysicalSize::new(ctx.viewport_size.width, ctx.viewport_size.height)));
6780 let text_items = split_text_for_whitespace(
6781 ctx.styled_dom,
6782 ifc_root_dom_id,
6783 text_content.as_str(),
6784 style,
6785 );
6786 content.extend(text_items);
6787 return Ok((content, child_map));
6788 }
6789
6790 let ifc_root_node_type = match ifc_root_node_data.get_node_type() {
6791 NodeType::Div => "Div",
6792 NodeType::Text(_) => "Text",
6793 NodeType::Body => "Body",
6794 _ => "Other",
6795 };
6796
6797 debug_info!(
6798 ctx,
6799 "[collect_and_measure_inline_content] IFC root has {} DOM children",
6800 dom_children.len()
6801 );
6802
6803 for (item_idx, &dom_child_id) in dom_children.iter().enumerate() {
6804 let content_index = ContentIndex {
6805 run_index: ifc_root_index as u32,
6806 item_index: item_idx as u32,
6807 };
6808
6809 let node_data = &ctx.styled_dom.node_data.as_container()[dom_child_id];
6810
6811 // Check if this is a text node
6812 if let NodeType::Text(ref text_content) = node_data.get_node_type() {
6813 debug_info!(
6814 ctx,
6815 "[collect_and_measure_inline_content] OK: Found text node (DOM child {:?}): '{}'",
6816 dom_child_id,
6817 text_content.as_str()
6818 );
6819
6820 // Get style from the TEXT NODE itself (dom_child_id), not the IFC root
6821 // This ensures inline styles like color: #666666 are applied to the text
6822 // Uses split_text_for_whitespace to correctly handle white-space: pre with \n
6823 let style = Arc::new(get_style_properties(ctx.styled_dom, dom_child_id, ctx.system_style.as_ref(), PhysicalSize::new(ctx.viewport_size.width, ctx.viewport_size.height)));
6824 let text_items = split_text_for_whitespace(
6825 ctx.styled_dom,
6826 dom_child_id,
6827 text_content.as_str(),
6828 style,
6829 );
6830 content.extend(text_items);
6831
6832 // Set IFC membership on the text node's layout node (if it exists)
6833 // Text nodes may or may not have their own layout tree entry depending on
6834 // whether they're wrapped in an anonymous IFC wrapper
6835 if let Some(&layout_idx) = tree.dom_to_layout.get(&dom_child_id).and_then(|v| v.first()) {
6836 if let Some(warm_mut) = tree.warm_mut(layout_idx) {
6837 warm_mut.ifc_membership = Some(IfcMembership {
6838 ifc_id,
6839 ifc_root_layout_index: ifc_root_index,
6840 run_index: current_run_index,
6841 });
6842 }
6843 }
6844 current_run_index += 1;
6845
6846 continue;
6847 }
6848
6849 // For non-text nodes, find their corresponding layout tree node
6850 let child_index = children
6851 .iter()
6852 .find(|&&idx| {
6853 tree.get(idx)
6854 .and_then(|n| n.dom_node_id)
6855 .map(|id| id == dom_child_id)
6856 .unwrap_or(false)
6857 })
6858 .copied();
6859
6860 let Some(child_index) = child_index else {
6861 debug_info!(
6862 ctx,
6863 "[collect_and_measure_inline_content] WARN: DOM child {:?} has no layout node",
6864 dom_child_id
6865 );
6866 continue;
6867 };
6868
6869 let child_node = tree.get(child_index).ok_or(LayoutError::InvalidTree)?;
6870 // At this point we have a non-text DOM child with a layout node
6871 let dom_id = child_node.dom_node_id.unwrap();
6872
6873 let display = get_display_property(ctx.styled_dom, Some(dom_id)).unwrap_or_default();
6874 if display != LayoutDisplay::Inline {
6875 // This is an atomic inline-level box (e.g., inline-block, image).
6876 // We must determine its size and baseline before passing it to text3.
6877
6878 // The intrinsic sizing pass has already calculated its preferred size.
6879 let intrinsic_size = tree.warm(child_index).and_then(|w| w.intrinsic_sizes.clone()).unwrap_or_default();
6880 let box_props = child_node.box_props.unpack();
6881
6882 let styled_node_state = ctx
6883 .styled_dom
6884 .styled_nodes
6885 .as_container()
6886 .get(dom_id)
6887 .map(|n| n.styled_node_state.clone())
6888 .unwrap_or_default();
6889
6890 // Calculate tentative border-box size based on CSS properties
6891 // This correctly handles explicit width/height, box-sizing, and constraints
6892 let tentative_size = crate::solver3::sizing::calculate_used_size_for_node(
6893 ctx.styled_dom,
6894 Some(dom_id),
6895 constraints.containing_block_size,
6896 intrinsic_size,
6897 &box_props,
6898 ctx.viewport_size,
6899 )?;
6900
6901 let writing_mode =
6902 get_writing_mode(ctx.styled_dom, dom_id, &styled_node_state).unwrap_or_default();
6903
6904 // Determine content-box size for laying out children
6905 let content_box_size = box_props.inner_size(tentative_size, writing_mode);
6906
6907 debug_info!(
6908 ctx,
6909 "[collect_and_measure_inline_content] Inline-block NodeId({:?}): \
6910 tentative_border_box={:?}, content_box={:?}",
6911 dom_id,
6912 tentative_size,
6913 content_box_size
6914 );
6915
6916 // To find its height and baseline, we must lay out its contents.
6917 let child_wm_ctx = super::geometry::WritingModeContext::new(
6918 writing_mode,
6919 get_direction_property(ctx.styled_dom, dom_id, &styled_node_state)
6920 .unwrap_or_default(),
6921 get_text_orientation_property(ctx.styled_dom, dom_id, &styled_node_state)
6922 .unwrap_or_default(),
6923 );
6924 let child_constraints = LayoutConstraints {
6925 available_size: LogicalSize::new(content_box_size.width, f32::INFINITY),
6926 writing_mode,
6927 writing_mode_ctx: child_wm_ctx,
6928 // Inline-blocks establish a new BFC, so no state is passed in.
6929 bfc_state: None,
6930 // Does not affect size/baseline of the container.
6931 text_align: TextAlign::Start,
6932 containing_block_size: constraints.containing_block_size,
6933 available_width_type: Text3AvailableSpace::Definite(content_box_size.width),
6934 };
6935
6936 // Drop the immutable borrow before calling layout_formatting_context
6937 drop(child_node);
6938
6939 // Recursively lay out the inline-block to get its final height and baseline.
6940 // Note: This does not affect its final position, only its dimensions.
6941 let mut empty_float_cache = HashMap::new();
6942 let layout_result = layout_formatting_context(
6943 ctx,
6944 tree,
6945 text_cache,
6946 child_index,
6947 &child_constraints,
6948 &mut empty_float_cache,
6949 )?;
6950
6951 let css_height = get_css_height(ctx.styled_dom, dom_id, &styled_node_state);
6952
6953 // Determine final border-box height
6954 let final_height = match css_height.clone().unwrap_or_default() {
6955 LayoutHeight::Auto => {
6956 // For auto height, add padding and border to the content height
6957 let content_height = layout_result.output.overflow_size.height;
6958 content_height
6959 + box_props.padding.main_sum(writing_mode)
6960 + box_props.border.main_sum(writing_mode)
6961 }
6962 // For explicit height, calculate_used_size_for_node already gave us the correct border-box height
6963 _ => tentative_size.height,
6964 };
6965
6966 debug_info!(
6967 ctx,
6968 "[collect_and_measure_inline_content] Inline-block NodeId({:?}): \
6969 layout_content_height={}, css_height={:?}, final_border_box_height={}",
6970 dom_id,
6971 layout_result.output.overflow_size.height,
6972 css_height,
6973 final_height
6974 );
6975
6976 let final_size = LogicalSize::new(tentative_size.width, final_height);
6977
6978 // Update the node in the tree with its now-known used size.
6979 tree.get_mut(child_index).unwrap().used_size = Some(final_size);
6980
6981 // CSS 2.2 § 10.8.1: For inline-block elements, the baseline is the baseline of the
6982 // last line box in the normal flow, unless it has either no in-flow line boxes or
6983 // if its 'overflow' property has a computed value other than 'visible', in which
6984 // case the baseline is the bottom margin edge.
6985 //
6986 // `layout_result.output.baseline` returns the Y-position of the baseline measured
6987 // from the TOP of the content box. But `get_item_vertical_metrics` expects
6988 // `baseline_offset` to be the distance from the BOTTOM to the baseline.
6989 //
6990 // Conversion: baseline_offset_from_bottom = height - baseline_from_top
6991 //
6992 // If no baseline is found (e.g., the inline-block has no text), or if
6993 // overflow is not 'visible', we fall back to the bottom margin edge
6994 // (baseline_offset = 0, meaning baseline at bottom).
6995 let overflow_x = get_overflow_x(ctx.styled_dom, dom_id, &styled_node_state).unwrap_or_default();
6996 let overflow_y = get_overflow_y(ctx.styled_dom, dom_id, &styled_node_state).unwrap_or_default();
6997 let overflow_is_visible = matches!(
6998 (overflow_x, overflow_y),
6999 (LayoutOverflow::Visible, LayoutOverflow::Visible)
7000 );
7001 let baseline_from_top = layout_result.output.baseline;
7002 let baseline_offset = match baseline_from_top {
7003 Some(baseline_y) if overflow_is_visible => {
7004 // baseline_y is measured from top of content box
7005 // We need to add padding and border to get the position within the border-box
7006 let content_box_top = box_props.padding.top + box_props.border.top;
7007 let baseline_from_border_box_top = baseline_y + content_box_top;
7008 // Convert to distance from bottom
7009 (final_height - baseline_from_border_box_top).max(0.0)
7010 }
7011 _ => {
7012 // No baseline found or overflow != visible - use bottom margin edge
7013 0.0
7014 }
7015 };
7016
7017 debug_info!(
7018 ctx,
7019 "[collect_and_measure_inline_content] Inline-block NodeId({:?}): \
7020 baseline_from_top={:?}, final_height={}, baseline_offset_from_bottom={}",
7021 dom_id,
7022 baseline_from_top,
7023 final_height,
7024 baseline_offset
7025 );
7026
7027 // Get margins for inline-block positioning
7028 // For inline-blocks, we need to include margins in the shape size
7029 // so that text3 positions them correctly with spacing
7030 let margin = &box_props.margin;
7031 let margin_box_width = final_size.width + margin.left + margin.right;
7032 let margin_box_height = final_size.height + margin.top + margin.bottom;
7033
7034 // For inline-block shapes, text3 uses the content array index as run_index
7035 // and always item_index=0 for objects. We must match this when inserting into child_map.
7036 let shape_content_index = ContentIndex {
7037 run_index: content.len() as u32,
7038 item_index: 0,
7039 };
7040 // the box used for alignment is the margin box" - using margin_box_width/height here
7041 content.push(InlineContent::Shape(InlineShape {
7042 shape_def: ShapeDefinition::Rectangle {
7043 size: crate::text3::cache::Size {
7044 // Use margin-box size for positioning in inline flow
7045 width: margin_box_width,
7046 height: margin_box_height,
7047 },
7048 corner_radius: None,
7049 },
7050 fill: None,
7051 stroke: None,
7052 // Adjust baseline offset by top margin
7053 baseline_offset: baseline_offset + margin.top,
7054 alignment: crate::solver3::getters::get_vertical_align_for_node(ctx.styled_dom, dom_id),
7055 source_node_id: Some(dom_id),
7056 }));
7057 child_map.insert(shape_content_index, child_index);
7058 } else if let NodeType::Image(image_ref) =
7059 ctx.styled_dom.node_data.as_container()[dom_id].get_node_type()
7060 {
7061 // +spec:replaced-elements:31a782 - replaced elements (img) not rendered purely by CSS box concepts
7062 // Images are replaced elements - they have intrinsic dimensions
7063 // and CSS width/height can constrain them
7064
7065 // Re-get child_node since we dropped it earlier for the inline-block case
7066 let child_node = tree.get(child_index).ok_or(LayoutError::InvalidTree)?;
7067 let box_props = child_node.box_props.unpack();
7068
7069 // Get intrinsic size from the image data or fall back to layout node
7070 let intrinsic_size = tree.warm(child_index)
7071 .and_then(|w| w.intrinsic_sizes.clone())
7072 .unwrap_or(IntrinsicSizes {
7073 max_content_width: 50.0,
7074 max_content_height: 50.0,
7075 ..Default::default()
7076 });
7077
7078 // Get styled node state for CSS property lookup
7079 let styled_node_state = ctx
7080 .styled_dom
7081 .styled_nodes
7082 .as_container()
7083 .get(dom_id)
7084 .map(|n| n.styled_node_state.clone())
7085 .unwrap_or_default();
7086
7087 // Calculate the used size respecting CSS width/height constraints
7088 let tentative_size = crate::solver3::sizing::calculate_used_size_for_node(
7089 ctx.styled_dom,
7090 Some(dom_id),
7091 constraints.containing_block_size,
7092 intrinsic_size.clone(),
7093 &box_props,
7094 ctx.viewport_size,
7095 )?;
7096
7097 // Drop immutable borrow before mutable access
7098 drop(child_node);
7099
7100 // Set the used_size on the layout node so paint_rect works correctly
7101 let final_size = LogicalSize::new(tentative_size.width, tentative_size.height);
7102 tree.get_mut(child_index).unwrap().used_size = Some(final_size);
7103
7104 // Calculate display size for text3 (this is what text3 uses for positioning)
7105 let display_width = if final_size.width > 0.0 {
7106 Some(final_size.width)
7107 } else {
7108 None
7109 };
7110 let display_height = if final_size.height > 0.0 {
7111 Some(final_size.height)
7112 } else {
7113 None
7114 };
7115
7116 content.push(InlineContent::Image(InlineImage {
7117 source: ImageSource::Ref(image_ref.as_ref().clone()),
7118 intrinsic_size: crate::text3::cache::Size {
7119 width: intrinsic_size.max_content_width,
7120 height: intrinsic_size.max_content_height,
7121 },
7122 display_size: if display_width.is_some() || display_height.is_some() {
7123 Some(crate::text3::cache::Size {
7124 width: display_width.unwrap_or(intrinsic_size.max_content_width),
7125 height: display_height.unwrap_or(intrinsic_size.max_content_height),
7126 })
7127 } else {
7128 None
7129 },
7130 // Images are bottom-aligned with the baseline by default
7131 baseline_offset: 0.0,
7132 alignment: crate::text3::cache::VerticalAlign::Baseline,
7133 object_fit: ObjectFit::Fill,
7134 }));
7135 // For images, text3 uses the content array index as run_index
7136 // and always item_index=0 for objects. We must match this.
7137 let image_content_index = ContentIndex {
7138 run_index: (content.len() - 1) as u32, // -1 because we just pushed
7139 item_index: 0,
7140 };
7141 child_map.insert(image_content_index, child_index);
7142 } else {
7143 // This is a regular inline box (display: inline) - e.g., <span>, <em>, <strong>
7144 //
7145 // According to CSS Inline-3 spec §2, inline boxes are "transparent" wrappers
7146 // We must recursively collect their text children with inherited style
7147 debug_info!(
7148 ctx,
7149 "[collect_and_measure_inline_content] Found inline span (DOM {:?}), recursing",
7150 dom_id
7151 );
7152
7153 let span_style = get_style_properties(ctx.styled_dom, dom_id, ctx.system_style.as_ref(), PhysicalSize::new(ctx.viewport_size.width, ctx.viewport_size.height));
7154 collect_inline_span_recursive(
7155 ctx,
7156 tree,
7157 dom_id,
7158 span_style,
7159 &mut content,
7160 &mut child_map,
7161 &children,
7162 constraints,
7163 )?;
7164 }
7165 }
7166 Ok((content, child_map))
7167}
7168
7169// +spec:display-property:c05c53 - inlinifying boxes can't contain block-level boxes; children are recursively inlinified
7170// it recursively inlinifies all of its in-flow children, so that no block-level descendants
7171// break up the inline formatting context in which it participates.
7172// +spec:display-property:aee879 - recursively inlinifies in-flow children of inline boxes
7173/// Recursively collects inline content from an inline span (display: inline) element.
7174///
7175/// According to CSS Inline Layout Module Level 3 §2:
7176///
7177/// "Inline boxes are transparent wrappers that wrap their content."
7178///
7179/// They don't create a new formatting context - their children participate in the
7180/// same IFC as the parent. This function processes:
7181///
7182/// - Text nodes: collected with the span's inherited style
7183/// - Nested inline spans: recursively descended
7184/// - Inline-blocks, images: measured and added as shapes
7185fn collect_inline_span_recursive<T: ParsedFontTrait>(
7186 ctx: &mut LayoutContext<'_, T>,
7187 tree: &mut LayoutTree,
7188 span_dom_id: NodeId,
7189 span_style: StyleProperties,
7190 content: &mut Vec<InlineContent>,
7191 child_map: &mut HashMap<ContentIndex, usize>,
7192 parent_children: &[usize], // Layout tree children of parent IFC
7193 constraints: &LayoutConstraints,
7194) -> Result<()> {
7195 debug_info!(
7196 ctx,
7197 "[collect_inline_span_recursive] Processing inline span {:?}",
7198 span_dom_id
7199 );
7200
7201 // Get DOM children of this span
7202 let span_dom_children: Vec<NodeId> = span_dom_id
7203 .az_children(&ctx.styled_dom.node_hierarchy.as_container())
7204 .collect();
7205
7206 debug_info!(
7207 ctx,
7208 "[collect_inline_span_recursive] Span has {} DOM children",
7209 span_dom_children.len()
7210 );
7211
7212 // +spec:box-model:b7428d - empty inline boxes still have margins, padding, borders, line-height
7213 // +spec:box-model:cc79a4 - empty inline elements still have margins, padding, borders and line height
7214 if span_dom_children.is_empty() {
7215 let node_state = &ctx.styled_dom.styled_nodes.as_container()[span_dom_id].styled_node_state;
7216 let font_size = get_element_font_size(ctx.styled_dom, span_dom_id, node_state);
7217
7218 let line_height_value = crate::solver3::getters::get_line_height_value(
7219 ctx.styled_dom, span_dom_id, &node_state
7220 );
7221 let line_height = line_height_value
7222 .map(|v| text3::cache::LineHeight::Px(v.inner.normalized() * font_size))
7223 .unwrap_or(text3::cache::LineHeight::Normal);
7224
7225 let cb_width = constraints.containing_block_size.main(constraints.writing_mode);
7226 let padding_top = crate::solver3::getters::get_css_padding_top(ctx.styled_dom, span_dom_id, &node_state)
7227 .exact().map(|pv| pv.to_pixels_internal(cb_width, font_size, DEFAULT_FONT_SIZE)).unwrap_or(0.0);
7228 let padding_bottom = crate::solver3::getters::get_css_padding_bottom(ctx.styled_dom, span_dom_id, &node_state)
7229 .exact().map(|pv| pv.to_pixels_internal(cb_width, font_size, DEFAULT_FONT_SIZE)).unwrap_or(0.0);
7230 let padding_left = crate::solver3::getters::get_css_padding_left(ctx.styled_dom, span_dom_id, &node_state)
7231 .exact().map(|pv| pv.to_pixels_internal(cb_width, font_size, DEFAULT_FONT_SIZE)).unwrap_or(0.0);
7232 let padding_right = crate::solver3::getters::get_css_padding_right(ctx.styled_dom, span_dom_id, &node_state)
7233 .exact().map(|pv| pv.to_pixels_internal(cb_width, font_size, DEFAULT_FONT_SIZE)).unwrap_or(0.0);
7234 let border_top = crate::solver3::getters::get_css_border_top_width(ctx.styled_dom, span_dom_id, &node_state)
7235 .exact().map(|pv| pv.to_pixels_internal(cb_width, font_size, DEFAULT_FONT_SIZE)).unwrap_or(0.0);
7236 let border_bottom = crate::solver3::getters::get_css_border_bottom_width(ctx.styled_dom, span_dom_id, &node_state)
7237 .exact().map(|pv| pv.to_pixels_internal(cb_width, font_size, DEFAULT_FONT_SIZE)).unwrap_or(0.0);
7238 let border_left = crate::solver3::getters::get_css_border_left_width(ctx.styled_dom, span_dom_id, &node_state)
7239 .exact().map(|pv| pv.to_pixels_internal(cb_width, font_size, DEFAULT_FONT_SIZE)).unwrap_or(0.0);
7240 let border_right = crate::solver3::getters::get_css_border_right_width(ctx.styled_dom, span_dom_id, &node_state)
7241 .exact().map(|pv| pv.to_pixels_internal(cb_width, font_size, DEFAULT_FONT_SIZE)).unwrap_or(0.0);
7242 let margin_left = crate::solver3::getters::get_css_margin_left(ctx.styled_dom, span_dom_id, &node_state)
7243 .exact().map(|pv| pv.to_pixels_internal(cb_width, font_size, DEFAULT_FONT_SIZE)).unwrap_or(0.0);
7244 let margin_right = crate::solver3::getters::get_css_margin_right(ctx.styled_dom, span_dom_id, &node_state)
7245 .exact().map(|pv| pv.to_pixels_internal(cb_width, font_size, DEFAULT_FONT_SIZE)).unwrap_or(0.0);
7246
7247 let resolved_line_height = line_height.resolve(font_size, 0.0, 0.0, 0.0, 0);
7248 let total_height = resolved_line_height + padding_top + padding_bottom + border_top + border_bottom;
7249 let total_width = margin_left + padding_left + border_left
7250 + border_right + padding_right + margin_right;
7251
7252 content.push(InlineContent::Shape(InlineShape {
7253 shape_def: ShapeDefinition::Rectangle {
7254 size: crate::text3::cache::Size {
7255 width: total_width,
7256 height: total_height,
7257 },
7258 corner_radius: None,
7259 },
7260 fill: None,
7261 stroke: None,
7262 baseline_offset: 0.0,
7263 alignment: crate::solver3::getters::get_vertical_align_for_node(ctx.styled_dom, span_dom_id),
7264 source_node_id: Some(span_dom_id),
7265 }));
7266
7267 return Ok(());
7268 }
7269
7270 for &child_dom_id in &span_dom_children {
7271 let node_data = &ctx.styled_dom.node_data.as_container()[child_dom_id];
7272
7273 // CASE 1: Text node - collect with span's style
7274 if let NodeType::Text(ref text_content) = node_data.get_node_type() {
7275 debug_info!(
7276 ctx,
7277 "[collect_inline_span_recursive] ✓ Found text in span: '{}'",
7278 text_content.as_str()
7279 );
7280 let text_items = split_text_for_whitespace(
7281 ctx.styled_dom,
7282 child_dom_id,
7283 text_content.as_str(),
7284 Arc::new(span_style.clone()),
7285 );
7286 content.extend(text_items);
7287 continue;
7288 }
7289
7290 // CASE 2: Element node - check its display type
7291 let child_display =
7292 get_display_property(ctx.styled_dom, Some(child_dom_id)).unwrap_or_default();
7293
7294 // Find the corresponding layout tree node
7295 let child_index = parent_children
7296 .iter()
7297 .find(|&&idx| {
7298 tree.get(idx)
7299 .and_then(|n| n.dom_node_id)
7300 .map(|id| id == child_dom_id)
7301 .unwrap_or(false)
7302 })
7303 .copied();
7304
7305 match child_display {
7306 LayoutDisplay::Inline => {
7307 // Nested inline span - recurse with child's style
7308 debug_info!(
7309 ctx,
7310 "[collect_inline_span_recursive] Found nested inline span {:?}",
7311 child_dom_id
7312 );
7313 let child_style = get_style_properties(ctx.styled_dom, child_dom_id, ctx.system_style.as_ref(), PhysicalSize::new(ctx.viewport_size.width, ctx.viewport_size.height));
7314 collect_inline_span_recursive(
7315 ctx,
7316 tree,
7317 child_dom_id,
7318 child_style,
7319 content,
7320 child_map,
7321 parent_children,
7322 constraints,
7323 )?;
7324 }
7325 LayoutDisplay::InlineBlock => {
7326 // Inline-block inside span - measure and add as shape
7327 let Some(child_index) = child_index else {
7328 debug_info!(
7329 ctx,
7330 "[collect_inline_span_recursive] WARNING: inline-block {:?} has no layout \
7331 node",
7332 child_dom_id
7333 );
7334 continue;
7335 };
7336
7337 let child_node = tree.get(child_index).ok_or(LayoutError::InvalidTree)?;
7338 let intrinsic_size = tree.warm(child_index).and_then(|w| w.intrinsic_sizes.clone()).unwrap_or_default();
7339 let width = intrinsic_size.max_content_width;
7340
7341 let styled_node_state = ctx
7342 .styled_dom
7343 .styled_nodes
7344 .as_container()
7345 .get(child_dom_id)
7346 .map(|n| n.styled_node_state.clone())
7347 .unwrap_or_default();
7348 let writing_mode =
7349 get_writing_mode(ctx.styled_dom, child_dom_id, &styled_node_state)
7350 .unwrap_or_default();
7351 let child_wm_ctx = super::geometry::WritingModeContext::new(
7352 writing_mode,
7353 get_direction_property(ctx.styled_dom, child_dom_id, &styled_node_state)
7354 .unwrap_or_default(),
7355 get_text_orientation_property(ctx.styled_dom, child_dom_id, &styled_node_state)
7356 .unwrap_or_default(),
7357 );
7358 let child_constraints = LayoutConstraints {
7359 available_size: LogicalSize::new(width, f32::INFINITY),
7360 writing_mode,
7361 writing_mode_ctx: child_wm_ctx,
7362 bfc_state: None,
7363 text_align: TextAlign::Start,
7364 containing_block_size: constraints.containing_block_size,
7365 available_width_type: Text3AvailableSpace::Definite(width),
7366 };
7367
7368 drop(child_node);
7369
7370 let mut empty_float_cache = HashMap::new();
7371 let layout_result = layout_formatting_context(
7372 ctx,
7373 tree,
7374 &mut TextLayoutCache::default(),
7375 child_index,
7376 &child_constraints,
7377 &mut empty_float_cache,
7378 )?;
7379 let final_height = layout_result.output.overflow_size.height;
7380 let final_size = LogicalSize::new(width, final_height);
7381
7382 tree.get_mut(child_index).unwrap().used_size = Some(final_size);
7383
7384 // CSS 2.2 § 10.8.1: inline-block baseline fallback
7385 let overflow_x = get_overflow_x(ctx.styled_dom, child_dom_id, &styled_node_state).unwrap_or_default();
7386 let overflow_y = get_overflow_y(ctx.styled_dom, child_dom_id, &styled_node_state).unwrap_or_default();
7387 let overflow_is_visible = matches!(
7388 (overflow_x, overflow_y),
7389 (LayoutOverflow::Visible, LayoutOverflow::Visible)
7390 );
7391 let baseline_offset = if overflow_is_visible {
7392 layout_result.output.baseline.unwrap_or(final_height)
7393 } else {
7394 final_height
7395 };
7396
7397 content.push(InlineContent::Shape(InlineShape {
7398 shape_def: ShapeDefinition::Rectangle {
7399 size: crate::text3::cache::Size {
7400 width,
7401 height: final_height,
7402 },
7403 corner_radius: None,
7404 },
7405 fill: None,
7406 stroke: None,
7407 baseline_offset,
7408 alignment: crate::solver3::getters::get_vertical_align_for_node(ctx.styled_dom, child_dom_id),
7409 source_node_id: Some(child_dom_id),
7410 }));
7411
7412 // Note: We don't add to child_map here because this is inside a span
7413 debug_info!(
7414 ctx,
7415 "[collect_inline_span_recursive] Added inline-block shape {}x{}",
7416 width,
7417 final_height
7418 );
7419 }
7420 _ => {
7421 // +spec:display-property:0684c4 - block box inlinified: inner display becomes flow-root (treated as atomic inline)
7422 // in-flow children of an inline box are recursively inlinified so they
7423 // don't break the IFC. Treat them as inline spans and recurse into their
7424 // children to collect text and inline content.
7425 debug_info!(
7426 ctx,
7427 "[collect_inline_span_recursive] Inlinifying block-level child {:?} \
7428 (display: {:?}) inside inline span per css-display-3 §2.7",
7429 child_dom_id,
7430 child_display
7431 );
7432 let child_style = get_style_properties(ctx.styled_dom, child_dom_id, ctx.system_style.as_ref(), PhysicalSize::new(ctx.viewport_size.width, ctx.viewport_size.height));
7433 collect_inline_span_recursive(
7434 ctx,
7435 tree,
7436 child_dom_id,
7437 child_style,
7438 content,
7439 child_map,
7440 parent_children,
7441 constraints,
7442 )?;
7443 }
7444 }
7445 }
7446
7447 Ok(())
7448}
7449
7450/// Positions a floated child within the BFC and updates the floating context.
7451/// This function is fully writing-mode aware.
7452fn position_floated_child(
7453 _child_index: usize,
7454 child_margin_box_size: LogicalSize,
7455 float_type: LayoutFloat,
7456 constraints: &LayoutConstraints,
7457 _bfc_content_box: LogicalRect,
7458 current_main_offset: f32,
7459 floating_context: &mut FloatingContext,
7460) -> Result<LogicalPosition> {
7461 let wm = constraints.writing_mode;
7462 let child_main_size = child_margin_box_size.main(wm);
7463 let child_cross_size = child_margin_box_size.cross(wm);
7464 let bfc_cross_size = constraints.available_size.cross(wm);
7465 let mut placement_main_offset = current_main_offset;
7466
7467 loop {
7468 // 1. Determine the available cross-axis space at the current
7469 // `placement_main_offset`.
7470 let (available_cross_start, available_cross_end) = floating_context
7471 .available_line_box_space(
7472 placement_main_offset,
7473 placement_main_offset + child_main_size,
7474 bfc_cross_size,
7475 wm,
7476 );
7477
7478 let available_cross_width = available_cross_end - available_cross_start;
7479
7480 // 2. Check if the new float can fit in the available space.
7481 if child_cross_size <= available_cross_width {
7482 // It fits! Determine the final position and add it to the context.
7483 // +spec:floats:5cfc93 - float:right positions box at cross-end, content flows on left
7484 let final_cross_pos = match float_type {
7485 LayoutFloat::Left => available_cross_start,
7486 // +spec:floats:5cfc93 - float:right positions box at cross-end, content flows on left
7487 LayoutFloat::Right => available_cross_end - child_cross_size,
7488 LayoutFloat::None => {
7489 return Err(LayoutError::PositioningFailed);
7490 }
7491 };
7492 let final_pos =
7493 LogicalPosition::from_main_cross(placement_main_offset, final_cross_pos, wm);
7494
7495 let new_float_box = FloatBox {
7496 kind: float_type,
7497 rect: LogicalRect::new(final_pos, child_margin_box_size),
7498 margin: EdgeSizes::default(), // TODO: Pass actual margin if this function is used
7499 };
7500 floating_context.floats.push(new_float_box);
7501 return Ok(final_pos);
7502 } else {
7503 // +spec:floats:3d89d8 - shift float downward when not enough horizontal room
7504 // It doesn't fit. We must move the float down past an obstacle.
7505 // Find the lowest main-axis end of all floats that are blocking
7506 // the current line.
7507 let mut next_main_offset = f32::INFINITY;
7508 for existing_float in &floating_context.floats {
7509 let float_main_start = existing_float.rect.origin.main(wm);
7510 let float_main_end = float_main_start + existing_float.rect.size.main(wm);
7511
7512 // Consider only floats that are above or at the current placement line.
7513 if placement_main_offset < float_main_end {
7514 next_main_offset = next_main_offset.min(float_main_end);
7515 }
7516 }
7517
7518 if next_main_offset.is_infinite() {
7519 // This indicates an unrecoverable state, e.g., a float wider
7520 // than the container.
7521 return Err(LayoutError::PositioningFailed);
7522 }
7523 placement_main_offset = next_main_offset;
7524 }
7525 }
7526}
7527
7528// CSS Property Getters
7529
7530/// Get the CSS `float` property for a node.
7531fn get_float_property(styled_dom: &StyledDom, dom_id: Option<NodeId>) -> LayoutFloat {
7532 let Some(id) = dom_id else {
7533 return LayoutFloat::None;
7534 };
7535 let node_state = &styled_dom.styled_nodes.as_container()[id].styled_node_state;
7536 get_float(styled_dom, id, node_state).unwrap_or(LayoutFloat::None)
7537}
7538
7539fn get_clear_property(styled_dom: &StyledDom, dom_id: Option<NodeId>) -> LayoutClear {
7540 let Some(id) = dom_id else {
7541 return LayoutClear::None;
7542 };
7543 let node_state = &styled_dom.styled_nodes.as_container()[id].styled_node_state;
7544 get_clear(styled_dom, id, node_state).unwrap_or(LayoutClear::None)
7545}
7546/// Helper to determine if scrollbars are needed.
7547///
7548/// # CSS Spec Reference
7549/// CSS Overflow Module Level 3 § 3: Scrollable overflow
7550// +spec:block-formatting-context:50d915 - overflow-x handles horizontal, overflow-y handles vertical
7551// +spec:box-model:63d6f2 - scrollable overflow extends beyond padding edge, needs scroll mechanism
7552// +spec:box-model:45b5fb - scrollbar space subtracted from content area, inserted between inner border edge and outer padding edge
7553// +spec:box-model:70a0a4 - UAs must start assuming no scrollbars needed, recalculate if they are
7554// +spec:box-model:c1b0b2 - scrollbar gutter is space between inner border edge and outer padding edge
7555// +spec:overflow:4f5b99 - scrollable overflow rectangle: content_size is the minimal axis-aligned rect containing scrollable overflow
7556// +spec:overflow:e983f4 - overflow:auto/scroll boxes must allow user to access overflowed content via scrollbars
7557// +spec:overflow:97c257 - relative positioning causing overflow in auto/scroll boxes must trigger scrollbar creation
7558pub fn check_scrollbar_necessity(
7559 content_size: LogicalSize,
7560 container_size: LogicalSize,
7561 overflow_x: OverflowBehavior,
7562 overflow_y: OverflowBehavior,
7563 scrollbar_width_px: f32,
7564) -> ScrollbarRequirements {
7565 // Use epsilon for float comparisons to avoid showing scrollbars due to
7566 // floating-point rounding errors. Without this, content that exactly fits
7567 // may show scrollbars due to sub-pixel differences (e.g., 299.9999 vs 300.0).
7568 const EPSILON: f32 = 1.0;
7569
7570 // +spec:height-calculation:c5af64 - assume no scrollbars initially; only add if content overflows
7571 // Determine if scrolling is needed based on overflow properties.
7572 // +spec:overflow:30a49c - start assuming no scrollbars, recalculate if needed
7573 // Note: scrollbar_width_px can be 0 for overlay scrollbars (e.g. macOS),
7574 // but we still need to register scroll nodes so that scrolling works —
7575 // overlay scrollbars just don't reserve any layout space.
7576 let mut needs_horizontal = match overflow_x {
7577 OverflowBehavior::Visible | OverflowBehavior::Hidden | OverflowBehavior::Clip => false,
7578 OverflowBehavior::Scroll => true,
7579 OverflowBehavior::Auto => content_size.width > container_size.width + EPSILON,
7580 };
7581
7582 let mut needs_vertical = match overflow_y {
7583 OverflowBehavior::Visible | OverflowBehavior::Hidden | OverflowBehavior::Clip => false,
7584 OverflowBehavior::Scroll => true,
7585 OverflowBehavior::Auto => content_size.height > container_size.height + EPSILON,
7586 };
7587
7588 // +spec:box-model:c3d73f - scrollbar presence affects available content area; padding preserved at scroll end
7589 // +spec:overflow:d79159 - scrollbar sizing: adding a scrollbar reduces available space,
7590 // which may cause content to overflow, confirming the scrollbar is needed (two-pass check)
7591 // A classic layout problem: a vertical scrollbar can reduce horizontal space,
7592 // causing a horizontal scrollbar to appear, which can reduce vertical space...
7593 // A full solution involves a loop, but this two-pass check handles most cases.
7594 // Only relevant when scrollbars reserve layout space (non-overlay).
7595 if scrollbar_width_px > 0.0 {
7596 if needs_vertical && !needs_horizontal && overflow_x == OverflowBehavior::Auto {
7597 if content_size.width > (container_size.width - scrollbar_width_px) + EPSILON {
7598 needs_horizontal = true;
7599 }
7600 }
7601 if needs_horizontal && !needs_vertical && overflow_y == OverflowBehavior::Auto {
7602 if content_size.height > (container_size.height - scrollbar_width_px) + EPSILON {
7603 needs_vertical = true;
7604 }
7605 }
7606 }
7607
7608 ScrollbarRequirements {
7609 needs_horizontal,
7610 needs_vertical,
7611 scrollbar_width: if needs_vertical {
7612 scrollbar_width_px
7613 } else {
7614 0.0
7615 },
7616 scrollbar_height: if needs_horizontal {
7617 scrollbar_width_px
7618 } else {
7619 0.0
7620 },
7621 // visual_width_px is set by the caller (compute_scrollbar_info_core)
7622 // since this function doesn't have access to the CSS style context.
7623 visual_width_px: 0.0,
7624 }
7625}
7626
7627/// Calculates a single collapsed margin from two adjoining vertical margins.
7628///
7629/// Implements the rules from CSS 2.1 section 8.3.1:
7630/// - If both margins are positive, the result is the larger of the two.
7631/// - If both margins are negative, the result is the more negative of the two.
7632/// - If the margins have mixed signs, they are effectively summed.
7633// +spec:margin-collapsing:814a26 - vertical margins between sibling blocks collapse
7634pub fn collapse_margins(a: f32, b: f32) -> f32 {
7635 if a.is_sign_positive() && b.is_sign_positive() {
7636 a.max(b)
7637 } else if a.is_sign_negative() && b.is_sign_negative() {
7638 a.min(b)
7639 } else {
7640 a + b
7641 }
7642}
7643
7644/// Helper function to advance the pen position with margin collapsing.
7645///
7646/// This implements CSS 2.1 margin collapsing for adjacent block-level boxes in a BFC.
7647///
7648/// - `pen` - Current main-axis position (will be modified)
7649/// - `last_margin_bottom` - The bottom margin of the previous in-flow element
7650/// - `current_margin_top` - The top margin of the current element
7651///
7652/// # Returns
7653///
7654/// The new `last_margin_bottom` value (the bottom margin of the current element)
7655///
7656/// # CSS Spec Compliance
7657///
7658/// Per CSS 2.1 Section 8.3.1 "Collapsing margins":
7659///
7660/// - Adjacent vertical margins of block boxes collapse
7661/// - The resulting margin width is the maximum of the adjoining margins (if both positive)
7662/// - Or the sum of the most positive and most negative (if signs differ)
7663fn advance_pen_with_margin_collapse(
7664 pen: &mut f32,
7665 last_margin_bottom: f32,
7666 current_margin_top: f32,
7667) -> f32 {
7668 // Collapse the previous element's bottom margin with current element's top margin
7669 let collapsed_margin = collapse_margins(last_margin_bottom, current_margin_top);
7670
7671 // Advance pen by the collapsed margin
7672 *pen += collapsed_margin;
7673
7674 // Return collapsed_margin so caller knows how much space was actually added
7675 collapsed_margin
7676}
7677
7678/// Checks if an element's border or padding prevents margin collapsing.
7679///
7680/// Per CSS 2.1 Section 8.3.1:
7681///
7682/// - Border between margins prevents collapsing
7683/// - Padding between margins prevents collapsing
7684///
7685/// # Arguments
7686///
7687/// - `box_props` - The box properties containing border and padding
7688/// - `writing_mode` - The writing mode to determine main axis
7689/// - `check_start` - If true, check main-start (top); if false, check main-end (bottom)
7690///
7691/// # Returns
7692///
7693/// `true` if border or padding exists and prevents collapsing
7694// +spec:box-model:ca8ceb - margin collapsing uses block-start/block-end per writing mode
7695fn has_margin_collapse_blocker(
7696 box_props: &crate::solver3::geometry::BoxProps,
7697 writing_mode: LayoutWritingMode,
7698 check_start: bool, // true = check top/start, false = check bottom/end
7699) -> bool {
7700 if check_start {
7701 // Check if there's border-top or padding-top
7702 let border_start = box_props.border.main_start(writing_mode);
7703 let padding_start = box_props.padding.main_start(writing_mode);
7704 border_start > 0.0 || padding_start > 0.0
7705 } else {
7706 // Check if there's border-bottom or padding-bottom
7707 let border_end = box_props.border.main_end(writing_mode);
7708 let padding_end = box_props.padding.main_end(writing_mode);
7709 border_end > 0.0 || padding_end > 0.0
7710 }
7711}
7712
7713/// Checks if an element is empty (has no content).
7714///
7715/// Per CSS 2.1 Section 8.3.1:
7716///
7717/// > If a block element has no border, padding, inline content, height, or min-height,
7718/// > then its top and bottom margins collapse with each other.
7719///
7720/// # Arguments
7721///
7722/// - `node` - The layout node to check
7723///
7724/// # Returns
7725///
7726/// `true` if the element is empty and its margins can collapse internally
7727fn is_empty_block(tree: &LayoutTree, node_index: usize) -> bool {
7728 let node = match tree.get(node_index) {
7729 Some(n) => n,
7730 None => return true,
7731 };
7732 // Per CSS 2.2 § 8.3.1: An empty block is one that:
7733 // - Has zero computed 'min-height'
7734 // - Has zero or 'auto' computed 'height'
7735 // - Has no in-flow children
7736 // - Has no line boxes (no text/inline content)
7737
7738 // Check if node has children
7739 if !tree.children(node_index).is_empty() {
7740 return false;
7741 }
7742
7743 // Check if node has inline content (text)
7744 if tree.warm(node_index).and_then(|w| w.inline_layout_result.as_ref()).is_some() {
7745 return false;
7746 }
7747
7748 // Check if node has explicit height > 0
7749 // CSS 2.2 § 8.3.1: Elements with explicit height are NOT empty
7750 if let Some(size) = node.used_size {
7751 if size.height > 0.0 {
7752 return false;
7753 }
7754 }
7755
7756 // Empty block: no children, no inline content, no height
7757 true
7758}
7759
7760/// Generates marker text for a list item marker.
7761///
7762/// This function looks up the counter value from the cache and formats it
7763/// according to the list-style-type property.
7764///
7765/// Per CSS Lists Module Level 3, the ::marker pseudo-element is the first child
7766/// of the list-item, and references the same DOM node. Counter resolution happens
7767/// on the list-item (parent) node.
7768fn generate_list_marker_text(
7769 tree: &LayoutTree,
7770 styled_dom: &StyledDom,
7771 marker_index: usize,
7772 counters: &HashMap<(usize, String), i32>,
7773 debug_messages: &mut Option<Vec<LayoutDebugMessage>>,
7774) -> String {
7775 use crate::solver3::counters::format_counter;
7776
7777 // Get the marker node
7778 let marker_node = match tree.get(marker_index) {
7779 Some(n) => n,
7780 None => return String::new(),
7781 };
7782
7783 // Verify this is actually a ::marker pseudo-element
7784 // Per spec, markers must be pseudo-elements, not anonymous boxes
7785 let marker_pseudo = tree.warm(marker_index).and_then(|w| w.pseudo_element);
7786 let marker_anonymous_type = tree.cold(marker_index).and_then(|c| c.anonymous_type);
7787 if marker_pseudo != Some(PseudoElement::Marker) {
7788 if let Some(msgs) = debug_messages {
7789 msgs.push(LayoutDebugMessage::warning(format!(
7790 "[generate_list_marker_text] WARNING: Node {} is not a ::marker pseudo-element \
7791 (pseudo={:?}, anonymous_type={:?})",
7792 marker_index, marker_pseudo, marker_anonymous_type
7793 )));
7794 }
7795 // Fallback for old-style anonymous markers during transition
7796 if marker_anonymous_type != Some(AnonymousBoxType::ListItemMarker) {
7797 return String::new();
7798 }
7799 }
7800
7801 // Get the parent list-item node (::marker is first child of list-item)
7802 let list_item_index = match marker_node.parent {
7803 Some(p) => p,
7804 None => {
7805 if let Some(msgs) = debug_messages {
7806 msgs.push(LayoutDebugMessage::error(
7807 "[generate_list_marker_text] ERROR: Marker has no parent".to_string(),
7808 ));
7809 }
7810 return String::new();
7811 }
7812 };
7813
7814 let list_item_node = match tree.get(list_item_index) {
7815 Some(n) => n,
7816 None => return String::new(),
7817 };
7818
7819 let list_item_dom_id = match list_item_node.dom_node_id {
7820 Some(id) => id,
7821 None => {
7822 if let Some(msgs) = debug_messages {
7823 msgs.push(LayoutDebugMessage::error(
7824 "[generate_list_marker_text] ERROR: List-item has no DOM ID".to_string(),
7825 ));
7826 }
7827 return String::new();
7828 }
7829 };
7830
7831 if let Some(msgs) = debug_messages {
7832 msgs.push(LayoutDebugMessage::info(format!(
7833 "[generate_list_marker_text] marker_index={}, list_item_index={}, \
7834 list_item_dom_id={:?}",
7835 marker_index, list_item_index, list_item_dom_id
7836 )));
7837 }
7838
7839 // Get list-style-type from the list-item or its container
7840 let list_container_dom_id = if let Some(grandparent_index) = list_item_node.parent {
7841 if let Some(grandparent) = tree.get(grandparent_index) {
7842 grandparent.dom_node_id
7843 } else {
7844 None
7845 }
7846 } else {
7847 None
7848 };
7849
7850 // Try to get list-style-type from the list container first,
7851 // then fall back to the list-item
7852 let list_style_type = if let Some(container_id) = list_container_dom_id {
7853 let container_type = get_list_style_type(styled_dom, Some(container_id));
7854 if container_type != StyleListStyleType::default() {
7855 container_type
7856 } else {
7857 get_list_style_type(styled_dom, Some(list_item_dom_id))
7858 }
7859 } else {
7860 get_list_style_type(styled_dom, Some(list_item_dom_id))
7861 };
7862
7863 // Get the counter value for "list-item" counter from the LIST-ITEM node
7864 // Per CSS spec, counters are scoped to elements, and the list-item counter
7865 // is incremented at the list-item element, not the marker pseudo-element
7866 let counter_value = counters
7867 .get(&(list_item_index, "list-item".to_string()))
7868 .copied()
7869 .unwrap_or_else(|| {
7870 if let Some(msgs) = debug_messages {
7871 msgs.push(LayoutDebugMessage::warning(format!(
7872 "[generate_list_marker_text] WARNING: No counter found for list-item at index \
7873 {}, defaulting to 1",
7874 list_item_index
7875 )));
7876 }
7877 1
7878 });
7879
7880 if let Some(msgs) = debug_messages {
7881 msgs.push(LayoutDebugMessage::info(format!(
7882 "[generate_list_marker_text] counter_value={} for list_item_index={}",
7883 counter_value, list_item_index
7884 )));
7885 }
7886
7887 // Format the counter according to the list-style-type
7888 let marker_text = format_counter(counter_value, list_style_type);
7889
7890 // For ordered lists (non-symbolic markers), add a period and space
7891 // For unordered lists (symbolic markers like •, ◦, ▪), just add a space
7892 if matches!(
7893 list_style_type,
7894 StyleListStyleType::Decimal
7895 | StyleListStyleType::DecimalLeadingZero
7896 | StyleListStyleType::LowerAlpha
7897 | StyleListStyleType::UpperAlpha
7898 | StyleListStyleType::LowerRoman
7899 | StyleListStyleType::UpperRoman
7900 | StyleListStyleType::LowerGreek
7901 | StyleListStyleType::UpperGreek
7902 ) {
7903 format!("{}. ", marker_text)
7904 } else {
7905 format!("{} ", marker_text)
7906 }
7907}
7908
7909/// Generates marker text segments for a list item marker.
7910///
7911/// Simply returns a single StyledRun with the marker text using the base_style.
7912/// The font stack in base_style already includes fallbacks with 100% Unicode coverage,
7913/// so font resolution happens during text shaping, not here.
7914fn generate_list_marker_segments(
7915 tree: &LayoutTree,
7916 styled_dom: &StyledDom,
7917 marker_index: usize,
7918 counters: &HashMap<(usize, String), i32>,
7919 base_style: Arc<StyleProperties>,
7920 debug_messages: &mut Option<Vec<LayoutDebugMessage>>,
7921) -> Vec<StyledRun> {
7922 // Generate the marker text
7923 let marker_text =
7924 generate_list_marker_text(tree, styled_dom, marker_index, counters, debug_messages);
7925 if marker_text.is_empty() {
7926 return Vec::new();
7927 }
7928
7929 if let Some(msgs) = debug_messages {
7930 let font_families: Vec<&str> = match &base_style.font_stack {
7931 crate::text3::cache::FontStack::Stack(selectors) => {
7932 selectors.iter().map(|f| f.family.as_str()).collect()
7933 }
7934 crate::text3::cache::FontStack::Ref(_) => vec!["<embedded-font>"],
7935 };
7936 msgs.push(LayoutDebugMessage::info(format!(
7937 "[generate_list_marker_segments] Marker text: '{}' with font stack: {:?}",
7938 marker_text,
7939 font_families
7940 )));
7941 }
7942
7943 // Return single segment - font fallback happens during shaping
7944 // List markers are generated content, not from DOM nodes
7945 vec![StyledRun {
7946 text: marker_text,
7947 style: base_style,
7948 logical_start_byte: 0,
7949 source_node_id: None,
7950 }]
7951}
7952
7953/// Returns true if a character has Unicode line breaking class BK (mandatory break)
7954/// or NL (next line). Per CSS Text 3 §5.1, these must be treated as forced line
7955/// breaks regardless of the white-space property value.
7956#[inline]
7957fn is_bk_or_nl_class(c: char) -> bool {
7958 matches!(c, '\u{000B}' | '\u{000C}' | '\u{0085}' | '\u{2028}' | '\u{2029}')
7959}
7960
7961/// Splits text at all forced break points: newlines (\n, \r\n, \r) and BK/NL class chars.
7962/// Used for white-space modes that preserve segment breaks (pre, pre-wrap, pre-line, break-spaces).
7963// +spec:white-space-processing:af4e3f - each newline/segment break in text is treated as a segment break, interpreted per white-space property
7964fn split_at_forced_breaks(text: &str) -> Vec<String> {
7965 let mut segments = Vec::new();
7966 let mut current = String::new();
7967 let mut chars = text.chars().peekable();
7968 while let Some(c) = chars.next() {
7969 if c == '\n' {
7970 segments.push(std::mem::take(&mut current));
7971 } else if c == '\r' {
7972 segments.push(std::mem::take(&mut current));
7973 if chars.peek() == Some(&'\n') {
7974 chars.next();
7975 }
7976 } else if is_bk_or_nl_class(c) {
7977 segments.push(std::mem::take(&mut current));
7978 } else {
7979 current.push(c);
7980 }
7981 }
7982 segments.push(current);
7983 segments
7984}
7985
7986/// Splits text only at BK/NL class characters (not \n which is collapsed in normal/nowrap).
7987/// Used for white-space: normal/nowrap where \n is collapsed to space but BK/NL chars
7988/// still produce forced breaks per CSS Text 3 §5.1.
7989fn split_at_bk_nl_chars(text: &str) -> Vec<String> {
7990 let mut segments = Vec::new();
7991 let mut current = String::new();
7992 for c in text.chars() {
7993 if is_bk_or_nl_class(c) {
7994 segments.push(std::mem::take(&mut current));
7995 } else {
7996 current.push(c);
7997 }
7998 }
7999 segments.push(current);
8000 segments
8001}
8002
8003/// Returns true if the character is East Asian (CJK) for the purposes of
8004/// segment break transformation rules (CSS Text Level 3, §4.1.3).
8005fn is_east_asian_wide(c: char) -> bool {
8006 let cp = c as u32;
8007 // CJK Unified Ideographs
8008 (0x4E00..=0x9FFF).contains(&cp)
8009 || (0x3400..=0x4DBF).contains(&cp)
8010 || (0x20000..=0x2A6DF).contains(&cp)
8011 || (0xF900..=0xFAFF).contains(&cp)
8012 // Hiragana
8013 || (0x3040..=0x309F).contains(&cp)
8014 // Katakana
8015 || (0x30A0..=0x30FF).contains(&cp)
8016 || (0x31F0..=0x31FF).contains(&cp)
8017 // CJK Radicals / Kangxi / Ideographic Description
8018 || (0x2E80..=0x2EFF).contains(&cp)
8019 || (0x2F00..=0x2FDF).contains(&cp)
8020 || (0x2FF0..=0x2FFF).contains(&cp)
8021 // CJK Symbols and Punctuation
8022 || (0x3000..=0x303F).contains(&cp)
8023 || (0x3200..=0x32FF).contains(&cp)
8024 || (0x3300..=0x33FF).contains(&cp)
8025 // Bopomofo
8026 || (0x3100..=0x312F).contains(&cp)
8027 // Hangul Syllables
8028 || (0xAC00..=0xD7AF).contains(&cp)
8029 // Fullwidth forms
8030 || (0xFF01..=0xFF60).contains(&cp)
8031 || (0xFFE0..=0xFFE6).contains(&cp)
8032}
8033
8034// +spec:block-formatting-context:b78223 - fullwidth/wide chars treated as vertical script, halfwidth as horizontal per UAX#11
8035fn is_east_asian_fullwidth_or_wide(ch: char) -> bool {
8036 let cp = ch as u32;
8037 // Exclude Hangul
8038 if (0x1100..=0x11FF).contains(&cp)
8039 || (0x3130..=0x318F).contains(&cp)
8040 || (0xAC00..=0xD7AF).contains(&cp)
8041 || (0xA960..=0xA97F).contains(&cp)
8042 || (0xD7B0..=0xD7FF).contains(&cp)
8043 {
8044 return false;
8045 }
8046 is_east_asian_wide(ch)
8047 || (0xFF61..=0xFFDC).contains(&cp)
8048 || (0xFFE8..=0xFFEE).contains(&cp)
8049 || (0xA000..=0xA4CF).contains(&cp)
8050}
8051
8052/// +spec:white-space-processing:159dbf - segment breaks converted to spaces (default transform)
8053/// +spec:white-space-processing:79891b - segment break transform: convert to space or remove
8054// +spec:white-space-processing:7e9529 - Segment break transformation rules (§4.1.3): collapse consecutive breaks, remove around ZWSP/CJK, else convert to space
8055/// Transforms segment breaks (newlines) in text according to CSS Text Level 3 §4.1.3.
8056/// - If adjacent to a zero-width space (U+200B), the segment break is removed.
8057/// - If both adjacent chars are East Asian F/W/H (not Hangul), removed entirely.
8058/// - Otherwise, converted to a single space.
8059fn apply_segment_break_transform(text: &str) -> String {
8060 let chars: Vec<char> = text.chars().collect();
8061 let len = chars.len();
8062 let mut result = String::with_capacity(text.len());
8063 let mut i = 0;
8064
8065 while i < len {
8066 let ch = chars[i];
8067 if ch == '\n' || ch == '\r' {
8068 let break_end = if ch == '\r' && i + 1 < len && chars[i + 1] == '\n' {
8069 i + 2
8070 } else {
8071 i + 1
8072 };
8073
8074 // +spec:white-space-processing:3c3680 - remove tabs/spaces around segment break before transform
8075 // §4.1.1: remove collapsible whitespace around segment breaks
8076 while result.ends_with(' ') || result.ends_with('\t') {
8077 result.pop();
8078 }
8079
8080 let mut after_idx = break_end;
8081 while after_idx < len && (chars[after_idx] == ' ' || chars[after_idx] == '\t') {
8082 after_idx += 1;
8083 }
8084
8085 let char_before = result.chars().last();
8086 let char_after = if after_idx < len { Some(chars[after_idx]) } else { None };
8087
8088 // Rule 1: adjacent to zero-width space → remove
8089 if char_before == Some('\u{200B}') || char_after == Some('\u{200B}') {
8090 // remove segment break
8091 }
8092 // Rule 2: both sides East Asian F/W/H (not Hangul) → remove
8093 else if let (Some(before), Some(after)) = (char_before, char_after) {
8094 if is_east_asian_fullwidth_or_wide(before) && is_east_asian_fullwidth_or_wide(after) {
8095 // remove segment break
8096 } else {
8097 result.push(' ');
8098 }
8099 } else {
8100 result.push(' ');
8101 }
8102
8103 i = after_idx;
8104 } else {
8105 result.push(ch);
8106 i += 1;
8107 }
8108 }
8109
8110 result
8111}
8112
8113// ============================================================================
8114// WHITE-SPACE PROCESSING PIPELINE (CSS Text Level 3 §4)
8115// ============================================================================
8116//
8117// +spec:white-space-processing:b64e38 - parser may normalize/collapse whitespace before CSS; CSS cannot restore
8118// The white-space processing pipeline is organized into four phases per the
8119// CSS Text Level 3 specification:
8120//
8121// Phase 1 (Collapse): Collapse whitespace sequences per §4.1.1
8122// Phase 2 (Segment Break Transform): Transform segment breaks per §4.1.3
8123// Phase 3 (Edge Trimming): Trim spaces at line start/end per §4.1.2
8124// Phase 4 (Tab Resolution): Resolve tab stops per §4.2
8125//
8126// Each phase is a standalone function that transforms a string, allowing
8127// spec patches to modify individual phases without touching others.
8128
8129/// Phase 1: Collapse consecutive whitespace to a single space.
8130/// CSS Text 3 §4.1.1 - applies to `normal`, `nowrap`, and `pre-line` modes.
8131pub fn ws_phase1_collapse(text: &str) -> String {
8132 let mut result = String::with_capacity(text.len());
8133 let mut prev_was_space = false;
8134 for ch in text.chars() {
8135 if ch == ' ' || ch == '\t' {
8136 if !prev_was_space {
8137 result.push(' ');
8138 prev_was_space = true;
8139 }
8140 } else {
8141 result.push(ch);
8142 prev_was_space = false;
8143 }
8144 }
8145 result
8146}
8147
8148/// Phase 2: Transform segment breaks (newlines) per CSS Text 3 §4.1.3.
8149/// Delegates to `apply_segment_break_transform` for the actual transformation rules.
8150pub fn ws_phase2_segment_break_transform(text: &str) -> String {
8151 apply_segment_break_transform(text)
8152}
8153
8154/// Phase 3: Trim leading/trailing collapsible whitespace at line boundaries.
8155/// CSS Text 3 §4.1.2 - this is a no-op during text collection; actual trimming
8156/// happens during line breaking when line start/end positions are known.
8157/// Provided as a pipeline slot for patches to hook into.
8158pub fn ws_phase3_trim_edges(text: &str) -> String {
8159 text.to_string()
8160}
8161
8162/// Phase 4: Resolve tab characters to spaces based on tab-size.
8163/// CSS Text 3 §4.2 - for `normal`/`nowrap`, tabs are collapsed to spaces in Phase 1.
8164/// For `pre`/`pre-wrap`/`break-spaces`, tabs are emitted as `InlineContent::Tab`
8165/// and resolved during line layout. This phase is a no-op during text collection.
8166pub fn ws_phase4_resolve_tabs(text: &str) -> String {
8167 text.to_string()
8168}
8169
8170/// Splits text content into InlineContent items based on white-space CSS property.
8171///
8172///
8173/// For `white-space: pre`, `pre-wrap`, and `pre-line`, newlines (`\n`) are treated as
8174/// forced line breaks per CSS Text Level 3 specification:
8175/// https://www.w3.org/TR/css-text-3/#white-space-property
8176///
8177/// Additionally, Unicode characters with BK or NL line breaking class (VT, FF, NEL, LS, PS)
8178/// are always treated as forced line breaks regardless of the white-space value.
8179///
8180/// This function:
8181/// 1. Checks the white-space property of the node (or its parent for text nodes)
8182/// 2. If `pre`, `pre-wrap`, or `pre-line`: splits text by `\n` and inserts `InlineContent::LineBreak`
8183/// 3. Otherwise: returns the text as a single `InlineContent::Text`
8184/// 4. In ALL modes: BK/NL class chars (VT, FF, NEL, LS, PS) produce forced breaks
8185///
8186/// Returns a Vec of InlineContent items that correctly represent line breaks.
8187
8188// +spec:display-property:1389e3 - bidi control characters per UAX #9 for Unicode bidirectional algorithm
8189// +spec:display-property:aad99b - inline boxes can be split into fragments due to bidi text processing
8190// Bidi_Control property (UAX #9). These characters are ignored during white-space processing.
8191fn is_bidi_control(c: char) -> bool {
8192 matches!(c,
8193 '\u{200E}' | // LEFT-TO-RIGHT MARK
8194 '\u{200F}' | // RIGHT-TO-LEFT MARK
8195 '\u{202A}' | // LEFT-TO-RIGHT EMBEDDING
8196 '\u{202B}' | // RIGHT-TO-LEFT EMBEDDING
8197 '\u{202C}' | // POP DIRECTIONAL FORMATTING
8198 '\u{202D}' | // LEFT-TO-RIGHT OVERRIDE
8199 '\u{202E}' | // RIGHT-TO-LEFT OVERRIDE
8200 '\u{2066}' | // LEFT-TO-RIGHT ISOLATE
8201 '\u{2067}' | // RIGHT-TO-LEFT ISOLATE
8202 '\u{2068}' | // FIRST STRONG ISOLATE
8203 '\u{2069}' | // POP DIRECTIONAL ISOLATE
8204 '\u{061C}' // ARABIC LETTER MARK
8205 )
8206}
8207
8208/// +spec:white-space-processing:1188f6 - only spaces, tabs, and segment breaks are document white space
8209/// Returns true if `c` is a CSS "document white space character" per CSS Text Level 3 §4.1.
8210/// Only spaces (U+0020), tabs (U+0009), and segment breaks (LF, CR, FF) qualify.
8211/// Other Unicode whitespace (e.g. U+00A0 non-breaking space) is NOT document white space.
8212#[inline]
8213pub fn is_css_document_whitespace(c: char) -> bool {
8214 matches!(c, ' ' | '\t' | '\n' | '\r' | '\x0C')
8215}
8216
8217// +spec:white-space-processing:efbece - white-space property controls collapsing/preserving of formatting characters for rendering
8218// +spec:writing-modes:b87688 - inlines laid out with bidi reordering and white-space wrapping
8219// +spec:writing-modes:cdd4f1 - white space trimming before bidi reordering preserves end-of-line spaces per UAX9 L1
8220// white space characters are processed prior to line breaking and bidi reordering
8221// +spec:inline-block:381c0c - white-space property: collapsing, wrapping, and forced breaks per mode
8222// +spec:display-property:8acfaa - Phase I white-space collapsing for each inline in an IFC, ignoring bidi controls
8223pub fn split_text_for_whitespace(
8224 styled_dom: &StyledDom,
8225 dom_id: NodeId,
8226 text: &str,
8227 style: Arc<StyleProperties>,
8228) -> Vec<InlineContent> {
8229 use crate::text3::cache::{BreakType, ClearType, InlineBreak};
8230
8231 // (characters with the Bidi_Control property) as if they were not there"
8232 // Strip bidi control characters before white-space processing so they don't
8233 // interfere with collapsing (e.g. a bidi mark between two spaces).
8234 let text_owned;
8235 let text: &str = if text.chars().any(|c| is_bidi_control(c)) {
8236 text_owned = text.chars().filter(|c| !is_bidi_control(*c)).collect::<String>();
8237 &text_owned
8238 } else {
8239 text
8240 };
8241
8242 // Get the white-space property - TEXT NODES inherit from parent!
8243 // We need to check the parent element's white-space, not the text node itself
8244 let node_hierarchy = styled_dom.node_hierarchy.as_container();
8245 let parent_id = node_hierarchy[dom_id].parent_id();
8246
8247 // Try parent first, then fall back to the node itself
8248 let white_space = if let Some(parent) = parent_id {
8249 let styled_nodes = styled_dom.styled_nodes.as_container();
8250 let parent_state = styled_nodes
8251 .get(parent)
8252 .map(|n| n.styled_node_state.clone())
8253 .unwrap_or_default();
8254
8255 match get_white_space_property(styled_dom, parent, &parent_state) {
8256 MultiValue::Exact(ws) => ws,
8257 _ => StyleWhiteSpace::Normal,
8258 }
8259 } else {
8260 StyleWhiteSpace::Normal
8261 };
8262
8263 let mut result = Vec::new();
8264
8265 // +spec:white-space-processing:3a0f58 - HTML newlines normalized to U+000A, each treated as segment break
8266 // +spec:white-space-processing:6eb1a2 - CR (U+000D) not treated as segment break by HTML; handle if inserted via DOM
8267 // HTML parsers convert \r to \n during preprocessing, but \r can survive
8268 // via escape sequences (e.g. 
). Any remaining U+000D must be
8269 // treated identically to U+000A (line feed).
8270 let text_cr;
8271 let text: &str = if text.contains('\r') {
8272 text_cr = text.replace("\r\n", "\n").replace('\r', "\n");
8273 &text_cr
8274 } else {
8275 text
8276 };
8277
8278 // +spec:white-space-processing:bd11da - white-space property: new lines, spaces/tabs, wrapping per value table
8279 // +spec:white-space-processing:b166c5 - segment breaks preserved as forced line feeds for pre/pre-wrap/break-spaces/pre-line
8280 // For `pre`, `pre-wrap`, `pre-line`, and `break-spaces`, newlines must be preserved as forced breaks
8281 // CSS Text Level 3: "Newlines in the source will be honored as forced line breaks."
8282 match white_space {
8283 StyleWhiteSpace::Pre | StyleWhiteSpace::PreWrap | StyleWhiteSpace::BreakSpaces => {
8284 // Pre, pre-wrap, break-spaces: preserve whitespace and honor newlines
8285 // Split by newlines and BK/NL class chars, insert LineBreak between parts
8286 // Also handle tab characters (\t) by inserting InlineContent::Tab
8287 let segments = split_at_forced_breaks(text);
8288 let segment_count = segments.len();
8289 let mut content_index = 0;
8290
8291 for (seg_idx, segment) in segments.into_iter().enumerate() {
8292 // Split the segment by tab characters and insert Tab elements
8293 let mut tab_parts = segment.split('\t').peekable();
8294 while let Some(part) = tab_parts.next() {
8295 if !part.is_empty() {
8296 result.push(InlineContent::Text(StyledRun {
8297 text: part.to_string(),
8298 style: Arc::clone(&style),
8299 logical_start_byte: 0,
8300 source_node_id: Some(dom_id),
8301 }));
8302 }
8303
8304 if tab_parts.peek().is_some() {
8305 result.push(InlineContent::Tab { style: Arc::clone(&style) });
8306 }
8307 }
8308
8309 if seg_idx + 1 < segment_count {
8310 result.push(InlineContent::LineBreak(InlineBreak {
8311 break_type: BreakType::Hard,
8312 clear: ClearType::None,
8313 content_index,
8314 }));
8315 content_index += 1;
8316 }
8317 }
8318 }
8319 StyleWhiteSpace::PreLine => {
8320 // Pre-line: collapse whitespace but honor newlines and BK/NL class chars
8321 let segments = split_at_forced_breaks(text);
8322 let segment_count = segments.len();
8323 let mut content_index = 0;
8324
8325 for (seg_idx, segment) in segments.into_iter().enumerate() {
8326 // Collapse only CSS document white space within the line (not all Unicode whitespace)
8327 let collapsed: String = segment
8328 .split(|c: char| is_css_document_whitespace(c))
8329 .filter(|s| !s.is_empty())
8330 .collect::<Vec<_>>()
8331 .join(" ");
8332
8333 if !collapsed.is_empty() {
8334 result.push(InlineContent::Text(StyledRun {
8335 text: collapsed,
8336 style: Arc::clone(&style),
8337 logical_start_byte: 0,
8338 source_node_id: Some(dom_id),
8339 }));
8340 }
8341
8342 if seg_idx + 1 < segment_count {
8343 result.push(InlineContent::LineBreak(InlineBreak {
8344 break_type: BreakType::Hard,
8345 clear: ClearType::None,
8346 content_index,
8347 }));
8348 content_index += 1;
8349 }
8350 }
8351 }
8352 StyleWhiteSpace::Normal | StyleWhiteSpace::Nowrap => {
8353 // +spec:white-space-processing:adbebb - Phase I collapsing for normal/nowrap modes
8354 // CSS Text Level 3, Section 4.1.1 - Phase I: Collapsing and Transformation
8355 // https://www.w3.org/TR/css-text-3/#white-space-phase-1
8356 //
8357 // For `white-space: normal` and `nowrap`:
8358 // 1. Segment breaks are transformed per §4.1.3
8359 // 2. Any sequence of consecutive spaces/tabs is collapsed to a single space
8360 // 3. Leading/trailing spaces at line boundaries are handled during line layout
8361 //
8362 // are forced breaks regardless of white-space value. Split on them first,
8363 // then collapse whitespace within each segment.
8364 let segments = split_at_bk_nl_chars(text);
8365 let segment_count = segments.len();
8366 let mut content_index = 0;
8367
8368 for (seg_idx, segment) in segments.into_iter().enumerate() {
8369 let after_segment_breaks = apply_segment_break_transform(&segment);
8370
8371 // Collapse document white space within this segment (normal/nowrap rules)
8372 let collapsed: String = after_segment_breaks
8373 .chars()
8374 .map(|c| if is_css_document_whitespace(c) { ' ' } else { c })
8375 .collect::<String>()
8376 .split(' ')
8377 .filter(|s| !s.is_empty())
8378 .collect::<Vec<_>>()
8379 .join(" ");
8380
8381 let final_text = if collapsed.is_empty() && !segment.is_empty() {
8382 " ".to_string()
8383 } else if !collapsed.is_empty() {
8384 // Check if original had leading/trailing document whitespace
8385 let had_leading = segment.chars().next().map(|c| is_css_document_whitespace(c)).unwrap_or(false);
8386 let had_trailing = segment.chars().last().map(|c| is_css_document_whitespace(c)).unwrap_or(false);
8387
8388 let mut r = String::new();
8389 if had_leading { r.push(' '); }
8390 r.push_str(&collapsed);
8391 if had_trailing && !had_leading { r.push(' '); }
8392 else if had_trailing && had_leading && collapsed.is_empty() { /* already have one space */ }
8393 else if had_trailing { r.push(' '); }
8394 r
8395 } else {
8396 collapsed
8397 };
8398
8399 if !final_text.is_empty() {
8400 result.push(InlineContent::Text(StyledRun {
8401 text: final_text,
8402 style: Arc::clone(&style),
8403 logical_start_byte: 0,
8404 source_node_id: Some(dom_id),
8405 }));
8406 }
8407
8408 // Insert forced break between segments (for BK/NL chars)
8409 if seg_idx + 1 < segment_count {
8410 result.push(InlineContent::LineBreak(InlineBreak {
8411 break_type: BreakType::Hard,
8412 clear: ClearType::None,
8413 content_index,
8414 }));
8415 content_index += 1;
8416 }
8417 }
8418 }
8419 }
8420
8421 // +spec:white-space-processing:5e3f70 - text-transform applied after Phase I collapsing, before Phase II trimming
8422 // This means full-width only transforms spaces (U+0020) to U+3000 IDEOGRAPHIC SPACE
8423 // within preserved white space, because non-preserved spaces were already collapsed in Phase I above.
8424 let text_transform = style.text_transform;
8425 if text_transform != crate::text3::cache::TextTransform::None {
8426 for item in result.iter_mut() {
8427 if let InlineContent::Text(run) = item {
8428 run.text = apply_text_transform(&run.text, text_transform);
8429 }
8430 }
8431 }
8432
8433 result
8434}
8435
8436fn apply_text_transform(text: &str, transform: crate::text3::cache::TextTransform) -> String {
8437 use crate::text3::cache::TextTransform;
8438 match transform {
8439 TextTransform::None => text.to_string(),
8440 TextTransform::Uppercase => text.to_uppercase(),
8441 TextTransform::Lowercase => text.to_lowercase(),
8442 TextTransform::Capitalize => {
8443 let mut result = String::with_capacity(text.len());
8444 let mut prev_is_word_boundary = true;
8445 for c in text.chars() {
8446 if prev_is_word_boundary && c.is_alphabetic() {
8447 for uc in c.to_uppercase() {
8448 result.push(uc);
8449 }
8450 prev_is_word_boundary = false;
8451 } else {
8452 result.push(c);
8453 prev_is_word_boundary = c.is_whitespace() || c.is_ascii_punctuation();
8454 }
8455 }
8456 result
8457 }
8458 TextTransform::FullWidth => {
8459 // Full-width transforms ASCII characters to their full-width equivalents.
8460 // Spaces (U+0020) become U+3000 IDEOGRAPHIC SPACE — but only those that
8461 // survived Phase I collapsing (i.e. preserved white space).
8462 text.chars().map(|c| match c {
8463 ' ' => '\u{3000}', // U+0020 SPACE -> U+3000 IDEOGRAPHIC SPACE
8464 '!' ..= '~' => {
8465 // ASCII printable range U+0021..U+007E -> fullwidth U+FF01..U+FF5E
8466 char::from_u32(c as u32 - 0x0021 + 0xFF01).unwrap_or(c)
8467 }
8468 _ => c,
8469 }).collect()
8470 }
8471 }
8472}
8473
8474// ============================================================================
8475// INITIAL LETTER / DROP CAPS STUB
8476// ============================================================================
8477
8478/// Computes the geometric exclusion area for an initial letter (drop cap).
8479///
8480/// CSS Inline Layout Module Level 3, section 3:
8481/// The `initial-letter` property specifies styling for dropped, raised, and sunken
8482/// initial letters. When set, the first glyph(s) of the first line are enlarged to
8483/// span multiple lines, with the remaining text wrapping around them.
8484///
8485// +spec:box-model:c93797 - initial-letter alignment points determined from contents (not border-box)
8486///
8487/// # Algorithm
8488///
8489/// 1. The letter box height spans `size` lines: `height = size * line_height`.
8490/// 2. The letter box width is estimated using a typical capital letter aspect ratio
8491/// (cap-height-to-advance-width ~0.7 for Latin text). A proper implementation
8492/// would measure the actual glyph, but this gives a reasonable default.
8493/// 3. The letter is positioned at the inline-start of the first line.
8494/// 4. The `sink` value determines how many lines the letter drops below the
8495/// first baseline. When `sink == size`, this is a classic drop cap.
8496/// When `sink < size`, the letter rises above the first line (raised cap).
8497/// 5. A small gap (4px default) is added between the letter box and adjacent text.
8498///
8499/// # Parameters
8500/// - `initial_letter_size`: The number of lines the initial letter should span (e.g., 3.0)
8501/// - `initial_letter_sink`: How many lines the letter sinks below the first line
8502/// - `content_box_width`: Available width in the content box (for clamping)
8503/// - `line_height`: The computed line height for the containing block
8504///
8505/// # Returns
8506/// A tuple of `(letter_width, letter_height)` representing the space reserved for
8507/// the initial letter exclusion, or `(0.0, 0.0)` if the parameters are invalid.
8508///
8509/// The caller should use these dimensions to create a float-like exclusion at the
8510/// start of the block container, causing subsequent lines to wrap around the letter.
8511// +spec:width-calculation:7f4f68 - initial-letter-wrap exclusion area (none behavior; first/grid require glyph outlines)
8512pub fn layout_initial_letter(
8513 initial_letter_size: f32,
8514 initial_letter_sink: u32,
8515 content_box_width: f32,
8516 line_height: f32,
8517) -> (f32, f32) {
8518 // Guard against degenerate values
8519 if initial_letter_size <= 0.0 || line_height <= 0.0 || content_box_width <= 0.0 {
8520 return (0.0, 0.0);
8521 }
8522
8523 // +spec:overflow:dd0679 - auto-sized initial letter content box fits exactly to content; alignment props do not apply
8524 // +spec:width-calculation:170742 - atomic initial letters with auto block size use inline initial letter sizing
8525 // CSS Inline Level 3 section 3.3: The initial letter box height spans `size` lines.
8526 let letter_height = initial_letter_size * line_height;
8527
8528 // Estimate the letter width using a typical Latin capital letter aspect ratio.
8529 // The advance width of a capital letter is approximately 0.7x the cap height.
8530 // This is a heuristic; a full implementation would measure the actual glyph(s).
8531 const CAP_WIDTH_RATIO: f32 = 0.7;
8532 let letter_width_raw = letter_height * CAP_WIDTH_RATIO;
8533
8534 // Add a small gap between the letter box and the adjacent inline content.
8535 // CSS Inline Level 3 section 3.5: browsers typically add ~4px padding.
8536 const LETTER_GAP: f32 = 4.0;
8537 let letter_width = (letter_width_raw + LETTER_GAP).min(content_box_width);
8538
8539 // +spec:containing-block:67fd99 - block-axis positioning: size >= sink shifts by (sink-1)*line_height toward block-end
8540 // The actual exclusion height accounts for the sink value.
8541 // sink == size means the letter is fully dropped (classic drop cap).
8542 // sink < size means part of the letter rises above the first line (raised cap).
8543 // The exclusion area height is always `sink * line_height` since that's how
8544 // many lines of subsequent text need to wrap around the letter.
8545 let exclusion_height = (initial_letter_sink as f32) * line_height;
8546
8547 // Use the larger of exclusion_height and letter_height as the actual
8548 // vertical space consumed. For raised caps (sink < size), the letter
8549 // extends above the first line but the exclusion only covers sink lines.
8550 // For sunken caps (sink >= size), the exclusion covers the full letter height.
8551 let effective_height = exclusion_height.max(letter_height);
8552
8553 (letter_width, effective_height)
8554}