repose_core/
view.rs

1use crate::{
2    BaselineShift, Brush, ClipOp, Color, DrawStyle, FontStyle, FontSynthesis, FontWeight, Modifier,
3    Rect, TextAlign, TextDecoration, TextDirection, TextSpan, Transform, Vec2,
4};
5use std::{fmt::Formatter, rc::Rc, sync::Arc};
6
7/// The constraints that will be passed to a subcomposed child. Values are in
8/// device-independent pixels (dp), matching the units used by `Modifier`.
9#[derive(Clone, Copy, Debug, PartialEq)]
10pub struct SubcomposeScope {
11    pub min_width: f32,
12    pub max_width: f32,
13    pub min_height: f32,
14    pub max_height: f32,
15}
16
17impl SubcomposeScope {
18    /// A scope with no constraints: unbounded in both dimensions. Use this as
19    /// a default when the parent constraints are not yet known.
20    pub const UNBOUNDED: Self = Self {
21        min_width: 0.0,
22        max_width: f32::INFINITY,
23        min_height: 0.0,
24        max_height: f32::INFINITY,
25    };
26
27    /// Construct a scope from raw min/max dp values.
28    pub fn new(min_width: f32, max_width: f32, min_height: f32, max_height: f32) -> Self {
29        Self {
30            min_width,
31            max_width,
32            min_height,
33            max_height,
34        }
35    }
36}
37
38/// Scope passed to [`BoxWithConstraints`](crate::prelude::BoxWithConstraints)
39/// content. All values are in dp.
40#[derive(Clone, Copy, Debug, PartialEq)]
41pub struct BoxWithConstraintsScope {
42    pub min_width: f32,
43    pub max_width: f32,
44    pub min_height: f32,
45    pub max_height: f32,
46}
47
48impl BoxWithConstraintsScope {
49    /// `true` if the width is bounded by the parent (i.e. not infinite).
50    pub fn has_bounded_width(&self) -> bool {
51        self.max_width.is_finite()
52    }
53
54    /// `true` if the height is bounded by the parent (i.e. not infinite).
55    pub fn has_bounded_height(&self) -> bool {
56        self.max_height.is_finite()
57    }
58}
59
60pub type ViewId = u64;
61
62pub type ImageHandle = u64;
63#[derive(Clone, Copy, Debug, PartialEq, Eq)]
64#[non_exhaustive]
65pub enum ImageFit {
66    /// ContentScale.Fit - default in Compose Image
67    Contain,
68    /// ContentScale.Crop
69    Cover,
70    /// ContentScale.FillWidth
71    FitWidth,
72    /// ContentScale.FillHeight
73    FitHeight,
74    /// ContentScale.FillBounds - stretch, ignore aspect
75    FillBounds,
76    /// ContentScale.Inside - like Contain but never upscales
77    Inside,
78    /// ContentScale.None - no scaling, top-left (alignment can offset later)
79    None,
80}
81
82pub type Callback = Rc<dyn Fn()>;
83
84#[derive(Clone)]
85pub struct OverlayEntry {
86    pub id: u64,
87    pub view: Box<View>,
88}
89
90#[derive(Clone)]
91#[non_exhaustive]
92pub enum ViewKind {
93    Box,
94    Row,
95    Column,
96    ZStack,
97    OverlayHost,
98    Text {
99        text: String,
100        color: Color,
101        font_size: f32,
102        soft_wrap: bool,
103        max_lines: Option<usize>,
104        overflow: TextOverflow,
105        font_family: Option<&'static str>,
106        annotations: Option<Arc<[TextSpan]>>,
107        text_align: TextAlign,
108        font_weight: FontWeight,
109        font_style: FontStyle,
110        text_decoration: TextDecoration,
111        letter_spacing: f32,
112        line_height: f32,
113        /// URL for clickable link text.
114        url: Option<Arc<str>>,
115        /// OpenType font variation settings (e.g. "wght 700, opsz 24").
116        font_variation_settings: Option<Arc<str>>,
117    },
118
119    Image {
120        handle: ImageHandle,
121        tint: Color, // multiplicative (WHITE = no tint)
122        fit: ImageFit,
123    },
124    /// A layout whose children are produced by calling `content` with the
125    /// current `SubcomposeScope`. The closure is invoked during reconciliation
126    /// and returns a list of `(slot_id, view)` pairs. Each slot id is a stable
127    /// identity used to reconcile the returned view across frames. This is
128    /// the building block for `BoxWithConstraints` and other
129    /// constraints-driven layouts.
130    ///
131    /// Note: any `Modifier::key` set on a returned view is overwritten by its
132    /// slot id so the slot's identity is stable across frames.
133    SubcomposeLayout {
134        content: Arc<dyn Fn(&SubcomposeScope) -> Vec<(u64, View)>>,
135    },
136    /// A collapsible section with a clickable header.
137    /// First child is the header content; remaining children shown only when expanded.
138    Expander {
139        expanded: bool,
140        on_toggle: Option<Callback>,
141    },
142    /// A single row in a tree view with indentation and expand/select support.
143    /// First child is rendered as the row label/content.
144    TreeRow {
145        depth: usize,
146        has_children: bool,
147        is_expanded: bool,
148        is_selected: bool,
149        on_toggle: Option<Callback>,
150        on_select: Option<Callback>,
151    },
152}
153
154impl std::fmt::Debug for ViewKind {
155    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
156        match self {
157            Self::Box => f.write_str("Box"),
158            Self::Row => f.write_str("Row"),
159            Self::Column => f.write_str("Column"),
160            Self::ZStack => f.write_str("ZStack"),
161            Self::OverlayHost => f.write_str("OverlayHost"),
162
163            Self::Image { .. } => f.write_str("Image"),
164            Self::SubcomposeLayout { .. } => f.write_str("SubcomposeLayout"),
165            Self::Text { text, .. } => write!(f, "Text({:?})", text),
166
167            Self::Expander { expanded, .. } => {
168                if *expanded {
169                    write!(f, "Expander(expanded)")
170                } else {
171                    write!(f, "Expander(collapsed)")
172                }
173            }
174            Self::TreeRow {
175                depth,
176                has_children,
177                is_expanded,
178                is_selected,
179                ..
180            } => {
181                write!(
182                    f,
183                    "TreeRow(depth={}, children={}, expanded={}, selected={})",
184                    depth, has_children, is_expanded, is_selected
185                )
186            }
187        }
188    }
189}
190
191#[derive(Clone, Debug)]
192pub struct View {
193    pub id: ViewId,
194    pub kind: ViewKind,
195    pub modifier: Modifier,
196    pub children: Vec<View>,
197    pub semantics: Option<crate::semantics::Semantics>,
198    /// Set by `scope!` macro to mark this as a scope boundary node.
199    /// Carries the scope key (e.g., "title", "color_buttons") for per-scope
200    /// TaffyTree isolation.
201    pub scope_key: Option<String>,
202}
203
204impl View {
205    pub fn new(id: ViewId, kind: ViewKind) -> Self {
206        View {
207            id,
208            kind,
209            modifier: Modifier::default(),
210            children: vec![],
211            semantics: None,
212            scope_key: None,
213        }
214    }
215    pub fn modifier(mut self, m: Modifier) -> Self {
216        self.modifier = m;
217        self
218    }
219    /// Mark this view as disabled - ignores pointer events.
220    pub fn disabled(mut self) -> Self {
221        self.modifier.disabled = true;
222        self
223    }
224    pub fn with_children(mut self, kids: Vec<View>) -> Self {
225        self.children = kids;
226        self
227    }
228    pub fn children(mut self, kids: impl Into<Vec<View>>) -> Self {
229        self.children = kids.into();
230        self
231    }
232    pub fn semantics(mut self, s: crate::semantics::Semantics) -> Self {
233        self.semantics = Some(s);
234        self
235    }
236}
237
238/// Renderable scene
239#[derive(Clone, Debug, Default)]
240pub struct Scene {
241    pub clear_color: Color,
242    pub nodes: Vec<SceneNode>,
243}
244
245/// Rarely-tweaked text style properties bundled for ergonomic Default.
246#[derive(Clone, Debug, PartialEq)]
247pub struct TextExtraStyle {
248    pub text_direction: TextDirection,
249    pub font_synthesis: FontSynthesis,
250    pub baseline_shift: BaselineShift,
251    pub draw_style: DrawStyle,
252}
253
254impl Default for TextExtraStyle {
255    fn default() -> Self {
256        Self {
257            text_direction: TextDirection::Ltr,
258            font_synthesis: FontSynthesis::Unspecified,
259            baseline_shift: BaselineShift::Unspecified,
260            draw_style: DrawStyle::Fill,
261        }
262    }
263}
264
265#[derive(Clone, Debug)]
266#[non_exhaustive]
267pub enum SceneNode {
268    Rect {
269        rect: Rect,
270        brush: Brush,
271        radius: [f32; 4],
272    },
273    Border {
274        rect: Rect,
275        color: Color,
276        width: f32,
277        radius: [f32; 4],
278    },
279    Text {
280        rect: Rect,
281        text: Arc<str>,
282        color: Color,
283        size: f32,
284        font_family: Option<&'static str>,
285        text_align: TextAlign,
286        font_weight: FontWeight,
287        font_style: FontStyle,
288        text_decoration: TextDecoration,
289        letter_spacing: f32,
290        line_height: f32,
291        /// Rarely-tweaked style properties, bundled for ergonomic Default.
292        extra_style: TextExtraStyle,
293        /// URL for clickable link text.
294        url: Option<Arc<str>>,
295        /// OpenType font variation settings (e.g. "wght 700, opsz 24").
296        font_variation_settings: Option<Arc<str>>,
297    },
298    Ellipse {
299        rect: Rect,
300        brush: Brush,
301    },
302    EllipseBorder {
303        rect: Rect,
304        color: Color,
305        width: f32, // screen-space width (px)
306    },
307    PushClip {
308        rect: Rect,
309        radius: [f32; 4],
310        op: ClipOp,
311    },
312    PopClip,
313    PushTransform {
314        transform: Transform,
315    },
316    PopTransform,
317    Image {
318        rect: Rect,
319        handle: ImageHandle,
320        tint: Color,
321        fit: ImageFit,
322    },
323    /// Shadow behind a rounded rect, typically driven by `StateElevation`.
324    /// The `elevation` field controls offset and alpha.
325    Shadow {
326        rect: Rect,
327        radius: [f32; 4],
328        elevation: f32,
329        color: Color,
330    },
331    /// Mark the start of a graphics layer: the contained subtree is rendered
332    /// into an offscreen texture and then composited back into the parent.
333    /// `alpha` is the group-compositing alpha applied at composite time.
334    /// `blur_radius_x` / `blur_radius_y` are the gaussian blur radii in pixels
335    /// applied to the layer before compositing (0.0 = no blur on that axis).
336    /// `rectangle_edge` when true means clamp edge pixels (Rectangle treatment);
337    /// when false, out-of-bounds samples are transparent (Unbounded).
338    BeginLayer {
339        rect: Rect,
340        layer_id: u32,
341        alpha: f32,
342        blur_radius_x: f32,
343        blur_radius_y: f32,
344        rectangle_edge: bool,
345    },
346    /// Closes the graphics layer opened by the matching `BeginLayer`.
347    EndLayer {
348        layer_id: u32,
349    },
350    /// Draws a blurred drop shadow underneath a previously-rendered layer.
351    /// Emitted between `EndLayer` and the layer's `CompositeLayer`. The
352    /// quad samples the layer's texture with a 3x3 Gaussian blur and an
353    /// optional vertical offset.
354    CompositeShadow {
355        layer_id: u32,
356        blur_px: f32,
357        offset_px: (f32, f32),
358        color: Color,
359    },
360    /// Arc stroke
361    Arc {
362        rect: Rect,
363        start_angle: f32,
364        sweep_angle: f32,
365        stroke_width: f32,
366        color: Color,
367        cap: StrokeCap,
368    },
369    /// Pre-tessellated vector mesh (fill or stroke geometry produced by the
370    /// host, e.g. lyon tessellation). Vertices live in the mesh's own local
371    /// space; `transform` is a 2x3 affine that maps local -> world pixels and
372    /// is applied in the vertex shader. The current scene `PushTransform`
373    /// stack is folded in on top of `transform`.
374    VectorMesh {
375        mesh: Arc<VectorMeshData>,
376        transform: [f32; 6],
377        paint: PaintDesc,
378        /// Reserved for explicit clip assignment; clipping is otherwise
379        /// structural via `PushVectorClip`/`PopVectorClip`.
380        clip: Option<u32>,
381        blend: BlendMode,
382    },
383    /// Screen-space overlays (handles, rubber bands, playhead, …). Each mesh
384    /// is positioned in final device pixels and is *not* affected by the
385    /// world `PushTransform` stack — emit these outside the viewport's world
386    /// transform scope.
387    VectorOverlay {
388        meshes: Arc<[VectorMeshData]>,
389    },
390    /// Start a vector clip: the mesh is rendered into the stencil buffer
391    /// (increment) and subsequent content is masked to it. Mirrors the
392    /// rect-based `PushClip` but for arbitrary tessellated masks.
393    PushVectorClip {
394        mesh: Arc<VectorMeshData>,
395    },
396    /// End a vector clip opened by `PushVectorClip`.
397    PopVectorClip,
398}
399
400/// Shared vertex/index buffers for a tessellated vector mesh.
401#[derive(Clone, Debug, Default)]
402pub struct VectorMeshData {
403    pub vertices: Arc<[VectorVertex]>,
404    pub indices: Arc<[u32]>,
405}
406
407/// Pre-tessellated vertex: local position, premultiplied-linear color, and a
408/// free-form uv channel (unused for solid fills, reserved for texture/gradient
409/// sampling).
410#[derive(Clone, Copy, Debug, PartialEq)]
411#[repr(C)]
412pub struct VectorVertex {
413    pub pos: [f32; 2],
414    pub color: [f32; 4],
415    pub uv: [f32; 2],
416}
417
418/// How a `VectorMesh` is painted.
419#[derive(Clone, Copy, Debug, PartialEq)]
420#[non_exhaustive]
421pub enum PaintDesc {
422    /// Use per-vertex color.
423    Solid,
424    /// Two-stop linear gradient in the mesh's local space.
425    Linear {
426        start: Vec2,
427        end: Vec2,
428        start_color: Color,
429        end_color: Color,
430    },
431}
432
433/// Blend mode for a `VectorMesh`. Only `Alpha` (premultiplied alpha) is wired
434/// into the renderer today; the remaining variants are reserved.
435#[derive(Clone, Copy, Debug, PartialEq, Eq)]
436#[non_exhaustive]
437#[derive(Default)]
438pub enum BlendMode {
439    /// Standard premultiplied alpha blending.
440    #[default]
441    Alpha,
442    /// Additive (screen-space light). Not yet implemented.
443    Add,
444    /// Multiply. Not yet implemented.
445    Multiply,
446    /// Overlay. Not yet implemented.
447    Overlay,
448}
449
450#[derive(Clone, Copy, Debug, PartialEq, Eq)]
451#[non_exhaustive]
452pub enum TextOverflow {
453    Visible,
454    Clip,
455    Ellipsis,
456}
457
458/// Controls how line segments are joined in a stroked path.
459#[derive(Clone, Copy, Debug, PartialEq, Default)]
460pub enum StrokeJoin {
461    #[default]
462    /// Sharp corner joins.
463    Miter,
464    /// Semi-circular joins.
465    Round,
466    /// Beveled (flat) joins.
467    Bevel,
468}
469
470/// Controls how the endpoints of a stroked arc are drawn.
471#[derive(Clone, Copy, Debug, PartialEq, Default)]
472pub enum StrokeCap {
473    #[default]
474    /// Flat ends at the exact arc endpoint. No extension.
475    Butt,
476    /// Semicircle with diameter equal to the stroke width, centered at the
477    /// arc endpoint.
478    Round,
479    /// Flat-ended rectangle extending half the stroke width beyond the arc
480    /// endpoint.
481    Square,
482}
483
484#[cfg(test)]
485mod tests {
486    use super::*;
487
488    #[test]
489    fn subcompose_scope_unbounded_has_infinite_max() {
490        let s = SubcomposeScope::UNBOUNDED;
491        assert!(!s.max_width.is_finite());
492        assert!(!s.max_height.is_finite());
493        assert_eq!(s.min_width, 0.0);
494        assert_eq!(s.min_height, 0.0);
495    }
496
497    #[test]
498    fn subcompose_scope_new_round_trips() {
499        let s = SubcomposeScope::new(10.0, 200.0, 20.0, 300.0);
500        assert_eq!(s.min_width, 10.0);
501        assert_eq!(s.max_width, 200.0);
502        assert_eq!(s.min_height, 20.0);
503        assert_eq!(s.max_height, 300.0);
504    }
505
506    #[test]
507    fn box_with_constraints_scope_bounded_predicates() {
508        let bounded = BoxWithConstraintsScope {
509            min_width: 0.0,
510            max_width: 360.0,
511            min_height: 0.0,
512            max_height: 640.0,
513        };
514        assert!(bounded.has_bounded_width());
515        assert!(bounded.has_bounded_height());
516
517        let unbounded = BoxWithConstraintsScope {
518            min_width: 0.0,
519            max_width: f32::INFINITY,
520            min_height: 0.0,
521            max_height: f32::INFINITY,
522        };
523        assert!(!unbounded.has_bounded_width());
524        assert!(!unbounded.has_bounded_height());
525    }
526
527    #[test]
528    fn view_kind_subcompose_layout_holds_closure() {
529        let v: View = View {
530            id: 0,
531            kind: ViewKind::SubcomposeLayout {
532                content: std::sync::Arc::new(|scope| {
533                    let _ = scope.max_width;
534                    vec![(0, View::new(0, ViewKind::Box))]
535                }),
536            },
537            modifier: Modifier::default(),
538            children: vec![],
539            scope_key: None,
540            semantics: None,
541        };
542        match &v.kind {
543            ViewKind::SubcomposeLayout { .. } => {}
544            _ => panic!("expected SubcomposeLayout"),
545        }
546    }
547
548    #[test]
549    fn view_kind_subcompose_layout_supports_multiple_slots() {
550        let v: View = View {
551            id: 0,
552            kind: ViewKind::SubcomposeLayout {
553                content: std::sync::Arc::new(|_scope| {
554                    vec![
555                        (1, View::new(0, ViewKind::Box)),
556                        (2, View::new(0, ViewKind::Box)),
557                        (3, View::new(0, ViewKind::Box)),
558                    ]
559                }),
560            },
561            modifier: Modifier::default(),
562            children: vec![],
563            scope_key: None,
564            semantics: None,
565        };
566        if let ViewKind::SubcomposeLayout { content } = &v.kind {
567            let slots = content(&SubcomposeScope::UNBOUNDED);
568            assert_eq!(slots.len(), 3);
569            assert_eq!(slots[0].0, 1);
570            assert_eq!(slots[1].0, 2);
571            assert_eq!(slots[2].0, 3);
572        } else {
573            panic!("expected SubcomposeLayout");
574        }
575    }
576}
repose_core/view.rs

repose_core/
view.rs
