repose_core/
view.rs

1use crate::{
2    BaselineShift, Brush, ClipOp, Color, DrawStyle, FontStyle, FontSynthesis, FontWeight, Modifier,
3    Rect, TextAlign, TextDecoration, TextDirection, TextSpan, Transform,
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    Contain,
67    Cover,
68    FitWidth,
69    FitHeight,
70}
71
72pub type Callback = Rc<dyn Fn()>;
73
74#[derive(Clone)]
75pub struct OverlayEntry {
76    pub id: u64,
77    pub view: Box<View>,
78}
79
80#[derive(Clone)]
81#[non_exhaustive]
82pub enum ViewKind {
83    Box,
84    Row,
85    Column,
86    ZStack,
87    OverlayHost,
88    Text {
89        text: String,
90        color: Color,
91        font_size: f32,
92        soft_wrap: bool,
93        max_lines: Option<usize>,
94        overflow: TextOverflow,
95        font_family: Option<&'static str>,
96        annotations: Option<Arc<[TextSpan]>>,
97        text_align: TextAlign,
98        font_weight: FontWeight,
99        font_style: FontStyle,
100        text_decoration: TextDecoration,
101        letter_spacing: f32,
102        line_height: f32,
103        /// URL for clickable link text.
104        url: Option<Arc<str>>,
105        /// OpenType font variation settings (e.g. "wght 700, opsz 24").
106        font_variation_settings: Option<Arc<str>>,
107    },
108
109    Image {
110        handle: ImageHandle,
111        tint: Color, // multiplicative (WHITE = no tint)
112        fit: ImageFit,
113    },
114    /// A layout whose children are produced by calling `content` with the
115    /// current `SubcomposeScope`. The closure is invoked during reconciliation
116    /// and returns a list of `(slot_id, view)` pairs. Each slot id is a stable
117    /// identity used to reconcile the returned view across frames. This is
118    /// the building block for `BoxWithConstraints` and other
119    /// constraints-driven layouts.
120    ///
121    /// Note: any `Modifier::key` set on a returned view is overwritten by its
122    /// slot id so the slot's identity is stable across frames.
123    SubcomposeLayout {
124        content: Arc<dyn Fn(&SubcomposeScope) -> Vec<(u64, View)>>,
125    },
126    /// A collapsible section with a clickable header.
127    /// First child is the header content; remaining children shown only when expanded.
128    Expander {
129        expanded: bool,
130        on_toggle: Option<Callback>,
131    },
132    /// A single row in a tree view with indentation and expand/select support.
133    /// First child is rendered as the row label/content.
134    TreeRow {
135        depth: usize,
136        has_children: bool,
137        is_expanded: bool,
138        is_selected: bool,
139        on_toggle: Option<Callback>,
140        on_select: Option<Callback>,
141    },
142}
143
144impl std::fmt::Debug for ViewKind {
145    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
146        match self {
147            Self::Box => f.write_str("Box"),
148            Self::Row => f.write_str("Row"),
149            Self::Column => f.write_str("Column"),
150            Self::ZStack => f.write_str("ZStack"),
151            Self::OverlayHost => f.write_str("OverlayHost"),
152
153            Self::Image { .. } => f.write_str("Image"),
154            Self::SubcomposeLayout { .. } => f.write_str("SubcomposeLayout"),
155            Self::Text { text, .. } => write!(f, "Text({:?})", text),
156
157            Self::Expander { expanded, .. } => {
158                if *expanded {
159                    write!(f, "Expander(expanded)")
160                } else {
161                    write!(f, "Expander(collapsed)")
162                }
163            }
164            Self::TreeRow {
165                depth,
166                has_children,
167                is_expanded,
168                is_selected,
169                ..
170            } => {
171                write!(
172                    f,
173                    "TreeRow(depth={}, children={}, expanded={}, selected={})",
174                    depth, has_children, is_expanded, is_selected
175                )
176            }
177        }
178    }
179}
180
181#[derive(Clone, Debug)]
182pub struct View {
183    pub id: ViewId,
184    pub kind: ViewKind,
185    pub modifier: Modifier,
186    pub children: Vec<View>,
187    pub semantics: Option<crate::semantics::Semantics>,
188    /// Set by `scope!` macro to mark this as a scope boundary node.
189    /// Carries the scope key (e.g., "title", "color_buttons") for per-scope
190    /// TaffyTree isolation.
191    pub scope_key: Option<String>,
192}
193
194impl View {
195    pub fn new(id: ViewId, kind: ViewKind) -> Self {
196        View {
197            id,
198            kind,
199            modifier: Modifier::default(),
200            children: vec![],
201            semantics: None,
202            scope_key: None,
203        }
204    }
205    pub fn modifier(mut self, m: Modifier) -> Self {
206        self.modifier = m;
207        self
208    }
209    /// Mark this view as disabled - ignores pointer events.
210    pub fn disabled(mut self) -> Self {
211        self.modifier.disabled = true;
212        self
213    }
214    pub fn with_children(mut self, kids: Vec<View>) -> Self {
215        self.children = kids;
216        self
217    }
218    pub fn children(mut self, kids: impl Into<Vec<View>>) -> Self {
219        self.children = kids.into();
220        self
221    }
222    pub fn semantics(mut self, s: crate::semantics::Semantics) -> Self {
223        self.semantics = Some(s);
224        self
225    }
226}
227
228/// Renderable scene
229#[derive(Clone, Debug, Default)]
230pub struct Scene {
231    pub clear_color: Color,
232    pub nodes: Vec<SceneNode>,
233}
234
235/// Rarely-tweaked text style properties bundled for ergonomic Default.
236#[derive(Clone, Debug, PartialEq)]
237pub struct TextExtraStyle {
238    pub text_direction: TextDirection,
239    pub font_synthesis: FontSynthesis,
240    pub baseline_shift: BaselineShift,
241    pub draw_style: DrawStyle,
242}
243
244impl Default for TextExtraStyle {
245    fn default() -> Self {
246        Self {
247            text_direction: TextDirection::Ltr,
248            font_synthesis: FontSynthesis::Unspecified,
249            baseline_shift: BaselineShift::Unspecified,
250            draw_style: DrawStyle::Fill,
251        }
252    }
253}
254
255#[derive(Clone, Debug)]
256#[non_exhaustive]
257pub enum SceneNode {
258    Rect {
259        rect: Rect,
260        brush: Brush,
261        radius: [f32; 4],
262    },
263    Border {
264        rect: Rect,
265        color: Color,
266        width: f32,
267        radius: [f32; 4],
268    },
269    Text {
270        rect: Rect,
271        text: Arc<str>,
272        color: Color,
273        size: f32,
274        font_family: Option<&'static str>,
275        text_align: TextAlign,
276        font_weight: FontWeight,
277        font_style: FontStyle,
278        text_decoration: TextDecoration,
279        letter_spacing: f32,
280        line_height: f32,
281        /// Rarely-tweaked style properties, bundled for ergonomic Default.
282        extra_style: TextExtraStyle,
283        /// URL for clickable link text.
284        url: Option<Arc<str>>,
285        /// OpenType font variation settings (e.g. "wght 700, opsz 24").
286        font_variation_settings: Option<Arc<str>>,
287    },
288    Ellipse {
289        rect: Rect,
290        brush: Brush,
291    },
292    EllipseBorder {
293        rect: Rect,
294        color: Color,
295        width: f32, // screen-space width (px)
296    },
297    PushClip {
298        rect: Rect,
299        radius: [f32; 4],
300        op: ClipOp,
301    },
302    PopClip,
303    PushTransform {
304        transform: Transform,
305    },
306    PopTransform,
307    Image {
308        rect: Rect,
309        handle: ImageHandle,
310        tint: Color,
311        fit: ImageFit,
312    },
313    /// Shadow behind a rounded rect, typically driven by `StateElevation`.
314    /// The `elevation` field controls offset and alpha.
315    Shadow {
316        rect: Rect,
317        radius: [f32; 4],
318        elevation: f32,
319        color: Color,
320    },
321    /// Mark the start of a graphics layer: the contained subtree is rendered
322    /// into an offscreen texture and then composited back into the parent.
323    /// `alpha` is the group-compositing alpha applied at composite time.
324    /// `blur_radius_x` / `blur_radius_y` are the gaussian blur radii in pixels
325    /// applied to the layer before compositing (0.0 = no blur on that axis).
326    /// `rectangle_edge` when true means clamp edge pixels (Rectangle treatment);
327    /// when false, out-of-bounds samples are transparent (Unbounded).
328    BeginLayer {
329        rect: Rect,
330        layer_id: u32,
331        alpha: f32,
332        blur_radius_x: f32,
333        blur_radius_y: f32,
334        rectangle_edge: bool,
335    },
336    /// Closes the graphics layer opened by the matching `BeginLayer`.
337    EndLayer {
338        layer_id: u32,
339    },
340    /// Draws a blurred drop shadow underneath a previously-rendered layer.
341    /// Emitted between `EndLayer` and the layer's `CompositeLayer`. The
342    /// quad samples the layer's texture with a 3x3 Gaussian blur and an
343    /// optional vertical offset.
344    CompositeShadow {
345        layer_id: u32,
346        blur_px: f32,
347        offset_px: (f32, f32),
348        color: Color,
349    },
350    /// Arc stroke
351    Arc {
352        rect: Rect,
353        start_angle: f32,
354        sweep_angle: f32,
355        stroke_width: f32,
356        color: Color,
357        cap: StrokeCap,
358    },
359}
360
361#[derive(Clone, Copy, Debug, PartialEq, Eq)]
362#[non_exhaustive]
363pub enum TextOverflow {
364    Visible,
365    Clip,
366    Ellipsis,
367}
368
369/// Controls how line segments are joined in a stroked path.
370#[derive(Clone, Copy, Debug, PartialEq, Default)]
371pub enum StrokeJoin {
372    #[default]
373    /// Sharp corner joins.
374    Miter,
375    /// Semi-circular joins.
376    Round,
377    /// Beveled (flat) joins.
378    Bevel,
379}
380
381/// Controls how the endpoints of a stroked arc are drawn.
382#[derive(Clone, Copy, Debug, PartialEq, Default)]
383pub enum StrokeCap {
384    #[default]
385    /// Flat ends at the exact arc endpoint. No extension.
386    Butt,
387    /// Semicircle with diameter equal to the stroke width, centered at the
388    /// arc endpoint.
389    Round,
390    /// Flat-ended rectangle extending half the stroke width beyond the arc
391    /// endpoint.
392    Square,
393}
394
395#[cfg(test)]
396mod tests {
397    use super::*;
398
399    #[test]
400    fn subcompose_scope_unbounded_has_infinite_max() {
401        let s = SubcomposeScope::UNBOUNDED;
402        assert!(!s.max_width.is_finite());
403        assert!(!s.max_height.is_finite());
404        assert_eq!(s.min_width, 0.0);
405        assert_eq!(s.min_height, 0.0);
406    }
407
408    #[test]
409    fn subcompose_scope_new_round_trips() {
410        let s = SubcomposeScope::new(10.0, 200.0, 20.0, 300.0);
411        assert_eq!(s.min_width, 10.0);
412        assert_eq!(s.max_width, 200.0);
413        assert_eq!(s.min_height, 20.0);
414        assert_eq!(s.max_height, 300.0);
415    }
416
417    #[test]
418    fn box_with_constraints_scope_bounded_predicates() {
419        let bounded = BoxWithConstraintsScope {
420            min_width: 0.0,
421            max_width: 360.0,
422            min_height: 0.0,
423            max_height: 640.0,
424        };
425        assert!(bounded.has_bounded_width());
426        assert!(bounded.has_bounded_height());
427
428        let unbounded = BoxWithConstraintsScope {
429            min_width: 0.0,
430            max_width: f32::INFINITY,
431            min_height: 0.0,
432            max_height: f32::INFINITY,
433        };
434        assert!(!unbounded.has_bounded_width());
435        assert!(!unbounded.has_bounded_height());
436    }
437
438    #[test]
439    fn view_kind_subcompose_layout_holds_closure() {
440        let v: View = View {
441            id: 0,
442            kind: ViewKind::SubcomposeLayout {
443                content: std::sync::Arc::new(|scope| {
444                    let _ = scope.max_width;
445                    vec![(0, View::new(0, ViewKind::Box))]
446                }),
447            },
448            modifier: Modifier::default(),
449            children: vec![],
450            scope_key: None,
451            semantics: None,
452        };
453        match &v.kind {
454            ViewKind::SubcomposeLayout { .. } => {}
455            _ => panic!("expected SubcomposeLayout"),
456        }
457    }
458
459    #[test]
460    fn view_kind_subcompose_layout_supports_multiple_slots() {
461        let v: View = View {
462            id: 0,
463            kind: ViewKind::SubcomposeLayout {
464                content: std::sync::Arc::new(|_scope| {
465                    vec![
466                        (1, View::new(0, ViewKind::Box)),
467                        (2, View::new(0, ViewKind::Box)),
468                        (3, View::new(0, ViewKind::Box)),
469                    ]
470                }),
471            },
472            modifier: Modifier::default(),
473            children: vec![],
474            scope_key: None,
475            semantics: None,
476        };
477        if let ViewKind::SubcomposeLayout { content } = &v.kind {
478            let slots = content(&SubcomposeScope::UNBOUNDED);
479            assert_eq!(slots.len(), 3);
480            assert_eq!(slots[0].0, 1);
481            assert_eq!(slots[1].0, 2);
482            assert_eq!(slots[2].0, 3);
483        } else {
484            panic!("expected SubcomposeLayout");
485        }
486    }
487}
repose_core/view.rs

repose_core/
view.rs
