repose_core/
view.rs

1use crate::{
2    Brush, ClipOp, Color, FontStyle, FontWeight, Modifier, Rect, TextAlign, TextDecoration,
3    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    Stack,
87    ZStack,
88    OverlayHost,
89    Text {
90        text: String,
91        color: Color,
92        font_size: f32,
93        soft_wrap: bool,
94        max_lines: Option<usize>,
95        overflow: TextOverflow,
96        font_family: Option<&'static str>,
97        annotations: Option<Arc<[TextSpan]>>,
98        text_align: TextAlign,
99        font_weight: FontWeight,
100        font_style: FontStyle,
101        text_decoration: TextDecoration,
102        letter_spacing: f32,
103        line_height: f32,
104        /// URL for clickable link text.
105        url: Option<Arc<str>>,
106    },
107
108    Image {
109        handle: ImageHandle,
110        tint: Color, // multiplicative (WHITE = no tint)
111        fit: ImageFit,
112    },
113    /// A layout whose children are produced by calling `content` with the
114    /// current `SubcomposeScope`. The closure is invoked during reconciliation
115    /// and returns a list of `(slot_id, view)` pairs. Each slot id is a stable
116    /// identity used to reconcile the returned view across frames. This is
117    /// the building block for `BoxWithConstraints` and other
118    /// constraints-driven layouts.
119    ///
120    /// Note: any `Modifier::key` set on a returned view is overwritten by its
121    /// slot id so the slot's identity is stable across frames.
122    SubcomposeLayout {
123        content: Arc<dyn Fn(&SubcomposeScope) -> Vec<(u64, View)>>,
124    },
125    /// A collapsible section with a clickable header.
126    /// First child is the header content; remaining children shown only when expanded.
127    Expander {
128        expanded: bool,
129        on_toggle: Option<Callback>,
130    },
131    /// A single row in a tree view with indentation and expand/select support.
132    /// First child is rendered as the row label/content.
133    TreeRow {
134        depth: usize,
135        has_children: bool,
136        is_expanded: bool,
137        is_selected: bool,
138        on_toggle: Option<Callback>,
139        on_select: Option<Callback>,
140    },
141}
142
143impl std::fmt::Debug for ViewKind {
144    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
145        match self {
146            Self::Box => f.write_str("Box"),
147            Self::Row => f.write_str("Row"),
148            Self::Column => f.write_str("Column"),
149            Self::Stack => f.write_str("Stack"),
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 semantics(mut self, s: crate::semantics::Semantics) -> Self {
219        self.semantics = Some(s);
220        self
221    }
222}
223
224/// Renderable scene
225#[derive(Clone, Debug, Default)]
226pub struct Scene {
227    pub clear_color: Color,
228    pub nodes: Vec<SceneNode>,
229}
230
231#[derive(Clone, Debug)]
232#[non_exhaustive]
233pub enum SceneNode {
234    Rect {
235        rect: Rect,
236        brush: Brush,
237        radius: [f32; 4],
238    },
239    Border {
240        rect: Rect,
241        color: Color,
242        width: f32,
243        radius: [f32; 4],
244    },
245    Text {
246        rect: Rect,
247        text: Arc<str>,
248        color: Color,
249        size: f32,
250        font_family: Option<&'static str>,
251        text_align: TextAlign,
252        font_weight: FontWeight,
253        font_style: FontStyle,
254        text_decoration: TextDecoration,
255        letter_spacing: f32,
256        line_height: f32,
257        /// URL for clickable link text.
258        url: Option<Arc<str>>,
259    },
260    Ellipse {
261        rect: Rect,
262        brush: Brush,
263    },
264    EllipseBorder {
265        rect: Rect,
266        color: Color,
267        width: f32, // screen-space width (px)
268    },
269    PushClip {
270        rect: Rect,
271        radius: [f32; 4],
272        op: ClipOp,
273    },
274    PopClip,
275    PushTransform {
276        transform: Transform,
277    },
278    PopTransform,
279    Image {
280        rect: Rect,
281        handle: ImageHandle,
282        tint: Color,
283        fit: ImageFit,
284    },
285    /// Shadow behind a rounded rect, typically driven by `StateElevation`.
286    /// The `elevation` field controls offset and alpha.
287    Shadow {
288        rect: Rect,
289        radius: [f32; 4],
290        elevation: f32,
291        color: Color,
292    },
293    /// Mark the start of a graphics layer: the contained subtree is rendered
294    /// into an offscreen texture and then composited back into the parent.
295    /// `alpha` is the group-compositing alpha applied at composite time.
296    /// `blur_radius_x` / `blur_radius_y` are the gaussian blur radii in pixels
297    /// applied to the layer before compositing (0.0 = no blur on that axis).
298    /// `rectangle_edge` when true means clamp edge pixels (Rectangle treatment);
299    /// when false, out-of-bounds samples are transparent (Unbounded).
300    BeginLayer {
301        rect: Rect,
302        layer_id: u32,
303        alpha: f32,
304        blur_radius_x: f32,
305        blur_radius_y: f32,
306        rectangle_edge: bool,
307    },
308    /// Closes the graphics layer opened by the matching `BeginLayer`.
309    EndLayer {
310        layer_id: u32,
311    },
312    /// Draws a blurred drop shadow underneath a previously-rendered layer.
313    /// Emitted between `EndLayer` and the layer's `CompositeLayer`. The
314    /// quad samples the layer's texture with a 3x3 Gaussian blur and an
315    /// optional vertical offset.
316    CompositeShadow {
317        layer_id: u32,
318        blur_px: f32,
319        offset_px: (f32, f32),
320        color: Color,
321    },
322    /// Arc stroke
323    Arc {
324        rect: Rect,
325        start_angle: f32,
326        sweep_angle: f32,
327        stroke_width: f32,
328        color: Color,
329        cap: StrokeCap,
330    },
331}
332
333#[derive(Clone, Copy, Debug, PartialEq, Eq)]
334#[non_exhaustive]
335pub enum TextOverflow {
336    Visible,
337    Clip,
338    Ellipsis,
339}
340
341/// Controls how the endpoints of a stroked arc are drawn.
342/// Mirrors [`StrokeCap`](https://developer.android.com/reference/kotlin/androidx/compose/ui/graphics/StrokeCap)
343/// in Compose.
344#[derive(Clone, Copy, Debug, PartialEq)]
345pub enum StrokeCap {
346    /// Flat ends at the exact arc endpoint. No extension.
347    Butt,
348    /// Semicircle with diameter equal to the stroke width, centered at the
349    /// arc endpoint.
350    Round,
351    /// Flat-ended rectangle extending half the stroke width beyond the arc
352    /// endpoint.
353    Square,
354}
355
356#[cfg(test)]
357mod tests {
358    use super::*;
359
360    #[test]
361    fn subcompose_scope_unbounded_has_infinite_max() {
362        let s = SubcomposeScope::UNBOUNDED;
363        assert!(!s.max_width.is_finite());
364        assert!(!s.max_height.is_finite());
365        assert_eq!(s.min_width, 0.0);
366        assert_eq!(s.min_height, 0.0);
367    }
368
369    #[test]
370    fn subcompose_scope_new_round_trips() {
371        let s = SubcomposeScope::new(10.0, 200.0, 20.0, 300.0);
372        assert_eq!(s.min_width, 10.0);
373        assert_eq!(s.max_width, 200.0);
374        assert_eq!(s.min_height, 20.0);
375        assert_eq!(s.max_height, 300.0);
376    }
377
378    #[test]
379    fn box_with_constraints_scope_bounded_predicates() {
380        let bounded = BoxWithConstraintsScope {
381            min_width: 0.0,
382            max_width: 360.0,
383            min_height: 0.0,
384            max_height: 640.0,
385        };
386        assert!(bounded.has_bounded_width());
387        assert!(bounded.has_bounded_height());
388
389        let unbounded = BoxWithConstraintsScope {
390            min_width: 0.0,
391            max_width: f32::INFINITY,
392            min_height: 0.0,
393            max_height: f32::INFINITY,
394        };
395        assert!(!unbounded.has_bounded_width());
396        assert!(!unbounded.has_bounded_height());
397    }
398
399    #[test]
400    fn view_kind_subcompose_layout_holds_closure() {
401        let v: View = View {
402            id: 0,
403            kind: ViewKind::SubcomposeLayout {
404                content: std::sync::Arc::new(|scope| {
405                    let _ = scope.max_width;
406                    vec![(0, View::new(0, ViewKind::Box))]
407                }),
408            },
409            modifier: Modifier::default(),
410            children: vec![],
411            scope_key: None,
412            semantics: None,
413        };
414        match &v.kind {
415            ViewKind::SubcomposeLayout { .. } => {}
416            _ => panic!("expected SubcomposeLayout"),
417        }
418    }
419
420    #[test]
421    fn view_kind_subcompose_layout_supports_multiple_slots() {
422        let v: View = View {
423            id: 0,
424            kind: ViewKind::SubcomposeLayout {
425                content: std::sync::Arc::new(|_scope| {
426                    vec![
427                        (1, View::new(0, ViewKind::Box)),
428                        (2, View::new(0, ViewKind::Box)),
429                        (3, View::new(0, ViewKind::Box)),
430                    ]
431                }),
432            },
433            modifier: Modifier::default(),
434            children: vec![],
435            scope_key: None,
436            semantics: None,
437        };
438        if let ViewKind::SubcomposeLayout { content } = &v.kind {
439            let slots = content(&SubcomposeScope::UNBOUNDED);
440            assert_eq!(slots.len(), 3);
441            assert_eq!(slots[0].0, 1);
442            assert_eq!(slots[1].0, 2);
443            assert_eq!(slots[2].0, 3);
444        } else {
445            panic!("expected SubcomposeLayout");
446        }
447    }
448}
repose_core/view.rs

repose_core/
view.rs
