presenter.rs

  1use crate::{
  2    app::{AppContext, MutableAppContext, WindowInvalidation},
  3    elements::Element,
  4    font_cache::FontCache,
  5    geometry::rect::RectF,
  6    json::{self, ToJson},
  7    keymap::Keystroke,
  8    platform::{CursorStyle, Event},
  9    scene::CursorRegion,
 10    text_layout::TextLayoutCache,
 11    Action, AnyModelHandle, AnyViewHandle, AnyWeakModelHandle, AssetCache, ElementBox, Entity,
 12    FontSystem, ModelHandle, MouseRegion, MouseRegionId, ReadModel, ReadView, RenderContext,
 13    RenderParams, Scene, UpgradeModelHandle, UpgradeViewHandle, View, ViewHandle, WeakModelHandle,
 14    WeakViewHandle,
 15};
 16use pathfinder_geometry::vector::{vec2f, Vector2F};
 17use serde_json::json;
 18use smallvec::SmallVec;
 19use std::{
 20    collections::{HashMap, HashSet},
 21    marker::PhantomData,
 22    ops::{Deref, DerefMut},
 23    sync::Arc,
 24};
 25
 26pub struct Presenter {
 27    window_id: usize,
 28    pub(crate) rendered_views: HashMap<usize, ElementBox>,
 29    parents: HashMap<usize, usize>,
 30    cursor_regions: Vec<CursorRegion>,
 31    mouse_regions: Vec<(MouseRegion, usize)>,
 32    font_cache: Arc<FontCache>,
 33    text_layout_cache: TextLayoutCache,
 34    asset_cache: Arc<AssetCache>,
 35    last_mouse_moved_event: Option<Event>,
 36    hovered_region_ids: HashSet<MouseRegionId>,
 37    clicked_region: Option<MouseRegion>,
 38    right_clicked_region: Option<MouseRegion>,
 39    prev_drag_position: Option<Vector2F>,
 40    titlebar_height: f32,
 41}
 42
 43impl Presenter {
 44    pub fn new(
 45        window_id: usize,
 46        titlebar_height: f32,
 47        font_cache: Arc<FontCache>,
 48        text_layout_cache: TextLayoutCache,
 49        asset_cache: Arc<AssetCache>,
 50        cx: &mut MutableAppContext,
 51    ) -> Self {
 52        Self {
 53            window_id,
 54            rendered_views: cx.render_views(window_id, titlebar_height),
 55            parents: HashMap::new(),
 56            cursor_regions: Default::default(),
 57            mouse_regions: Default::default(),
 58            font_cache,
 59            text_layout_cache,
 60            asset_cache,
 61            last_mouse_moved_event: None,
 62            hovered_region_ids: Default::default(),
 63            clicked_region: None,
 64            right_clicked_region: None,
 65            prev_drag_position: None,
 66            titlebar_height,
 67        }
 68    }
 69
 70    pub fn dispatch_path(&self, app: &AppContext) -> Vec<usize> {
 71        let mut path = Vec::new();
 72        if let Some(view_id) = app.focused_view_id(self.window_id) {
 73            self.compute_dispatch_path_from(view_id, &mut path)
 74        }
 75        path
 76    }
 77
 78    pub(crate) fn compute_dispatch_path_from(&self, mut view_id: usize, path: &mut Vec<usize>) {
 79        path.push(view_id);
 80        while let Some(parent_id) = self.parents.get(&view_id).copied() {
 81            path.push(parent_id);
 82            view_id = parent_id;
 83        }
 84        path.reverse();
 85    }
 86
 87    pub fn invalidate(
 88        &mut self,
 89        invalidation: &mut WindowInvalidation,
 90        cx: &mut MutableAppContext,
 91    ) {
 92        cx.start_frame();
 93        for view_id in &invalidation.removed {
 94            invalidation.updated.remove(&view_id);
 95            self.rendered_views.remove(&view_id);
 96            self.parents.remove(&view_id);
 97        }
 98        for view_id in &invalidation.updated {
 99            self.rendered_views.insert(
100                *view_id,
101                cx.render_view(RenderParams {
102                    window_id: self.window_id,
103                    view_id: *view_id,
104                    titlebar_height: self.titlebar_height,
105                    hovered_region_ids: self.hovered_region_ids.clone(),
106                    clicked_region_id: self.clicked_region.as_ref().and_then(MouseRegion::id),
107                    right_clicked_region_id: self
108                        .right_clicked_region
109                        .as_ref()
110                        .and_then(MouseRegion::id),
111                    refreshing: false,
112                })
113                .unwrap(),
114            );
115        }
116    }
117
118    pub fn refresh(&mut self, invalidation: &mut WindowInvalidation, cx: &mut MutableAppContext) {
119        self.invalidate(invalidation, cx);
120        for (view_id, view) in &mut self.rendered_views {
121            if !invalidation.updated.contains(view_id) {
122                *view = cx
123                    .render_view(RenderParams {
124                        window_id: self.window_id,
125                        view_id: *view_id,
126                        titlebar_height: self.titlebar_height,
127                        hovered_region_ids: self.hovered_region_ids.clone(),
128                        clicked_region_id: self.clicked_region.as_ref().and_then(MouseRegion::id),
129                        right_clicked_region_id: self
130                            .right_clicked_region
131                            .as_ref()
132                            .and_then(MouseRegion::id),
133                        refreshing: true,
134                    })
135                    .unwrap();
136            }
137        }
138    }
139
140    pub fn build_scene(
141        &mut self,
142        window_size: Vector2F,
143        scale_factor: f32,
144        refreshing: bool,
145        cx: &mut MutableAppContext,
146    ) -> Scene {
147        let mut scene = Scene::new(scale_factor);
148
149        if let Some(root_view_id) = cx.root_view_id(self.window_id) {
150            self.layout(window_size, refreshing, cx);
151            let mut paint_cx = self.build_paint_context(&mut scene, window_size, cx);
152            paint_cx.paint(
153                root_view_id,
154                Vector2F::zero(),
155                RectF::new(Vector2F::zero(), window_size),
156            );
157            self.text_layout_cache.finish_frame();
158            self.cursor_regions = scene.cursor_regions();
159            self.mouse_regions = scene.mouse_regions();
160
161            if cx.window_is_active(self.window_id) {
162                if let Some(event) = self.last_mouse_moved_event.clone() {
163                    let mut invalidated_views = Vec::new();
164                    self.handle_hover_events(&event, &mut invalidated_views, cx);
165
166                    for view_id in invalidated_views {
167                        cx.notify_view(self.window_id, view_id);
168                    }
169                }
170            }
171        } else {
172            log::error!("could not find root_view_id for window {}", self.window_id);
173        }
174
175        scene
176    }
177
178    fn layout(&mut self, window_size: Vector2F, refreshing: bool, cx: &mut MutableAppContext) {
179        if let Some(root_view_id) = cx.root_view_id(self.window_id) {
180            self.build_layout_context(window_size, refreshing, cx)
181                .layout(root_view_id, SizeConstraint::strict(window_size));
182        }
183    }
184
185    pub fn build_layout_context<'a>(
186        &'a mut self,
187        window_size: Vector2F,
188        refreshing: bool,
189        cx: &'a mut MutableAppContext,
190    ) -> LayoutContext<'a> {
191        LayoutContext {
192            window_id: self.window_id,
193            rendered_views: &mut self.rendered_views,
194            parents: &mut self.parents,
195            font_cache: &self.font_cache,
196            font_system: cx.platform().fonts(),
197            text_layout_cache: &self.text_layout_cache,
198            asset_cache: &self.asset_cache,
199            view_stack: Vec::new(),
200            refreshing,
201            hovered_region_ids: self.hovered_region_ids.clone(),
202            clicked_region_id: self.clicked_region.as_ref().and_then(MouseRegion::id),
203            right_clicked_region_id: self.right_clicked_region.as_ref().and_then(MouseRegion::id),
204            titlebar_height: self.titlebar_height,
205            window_size,
206            app: cx,
207        }
208    }
209
210    pub fn build_paint_context<'a>(
211        &'a mut self,
212        scene: &'a mut Scene,
213        window_size: Vector2F,
214        cx: &'a mut MutableAppContext,
215    ) -> PaintContext {
216        PaintContext {
217            scene,
218            window_size,
219            font_cache: &self.font_cache,
220            text_layout_cache: &self.text_layout_cache,
221            rendered_views: &mut self.rendered_views,
222            view_stack: Vec::new(),
223            app: cx,
224        }
225    }
226
227    pub fn dispatch_event(&mut self, event: Event, cx: &mut MutableAppContext) -> bool {
228        if let Some(root_view_id) = cx.root_view_id(self.window_id) {
229            let mut invalidated_views = Vec::new();
230            let mut mouse_down_out_handlers = Vec::new();
231            let mut mouse_down_region = None;
232            let mut clicked_region = None;
233            let mut right_mouse_down_region = None;
234            let mut right_clicked_region = None;
235            let mut dragged_region = None;
236
237            match event {
238                Event::LeftMouseDown { position, .. } => {
239                    let mut hit = false;
240                    for (region, _) in self.mouse_regions.iter().rev() {
241                        if region.bounds.contains_point(position) {
242                            if !hit {
243                                hit = true;
244                                invalidated_views.push(region.view_id);
245                                mouse_down_region = Some((region.clone(), position));
246                                self.clicked_region = Some(region.clone());
247                                self.prev_drag_position = Some(position);
248                            }
249                        } else if let Some(handler) = region.mouse_down_out.clone() {
250                            mouse_down_out_handlers.push((handler, region.view_id, position));
251                        }
252                    }
253                }
254                Event::LeftMouseUp {
255                    position,
256                    click_count,
257                    ..
258                } => {
259                    self.prev_drag_position.take();
260                    if let Some(region) = self.clicked_region.take() {
261                        invalidated_views.push(region.view_id);
262                        if region.bounds.contains_point(position) {
263                            clicked_region = Some((region, position, click_count));
264                        }
265                    }
266                }
267                Event::RightMouseDown { position, .. } => {
268                    let mut hit = false;
269                    for (region, _) in self.mouse_regions.iter().rev() {
270                        if region.bounds.contains_point(position) {
271                            if !hit {
272                                hit = true;
273                                invalidated_views.push(region.view_id);
274                                right_mouse_down_region = Some((region.clone(), position));
275                                self.right_clicked_region = Some(region.clone());
276                            }
277                        } else if let Some(handler) = region.right_mouse_down_out.clone() {
278                            mouse_down_out_handlers.push((handler, region.view_id, position));
279                        }
280                    }
281                }
282                Event::RightMouseUp {
283                    position,
284                    click_count,
285                    ..
286                } => {
287                    if let Some(region) = self.right_clicked_region.take() {
288                        invalidated_views.push(region.view_id);
289                        if region.bounds.contains_point(position) {
290                            right_clicked_region = Some((region, position, click_count));
291                        }
292                    }
293                }
294                Event::MouseMoved { .. } => {
295                    self.last_mouse_moved_event = Some(event.clone());
296                }
297                Event::LeftMouseDragged {
298                    position,
299                    shift,
300                    ctrl,
301                    alt,
302                    cmd,
303                } => {
304                    if let Some((clicked_region, prev_drag_position)) = self
305                        .clicked_region
306                        .as_ref()
307                        .zip(self.prev_drag_position.as_mut())
308                    {
309                        dragged_region =
310                            Some((clicked_region.clone(), position - *prev_drag_position));
311                        *prev_drag_position = position;
312                    }
313
314                    self.last_mouse_moved_event = Some(Event::MouseMoved {
315                        position,
316                        left_mouse_down: true,
317                        shift,
318                        ctrl,
319                        alt,
320                        cmd,
321                    });
322                }
323                _ => {}
324            }
325
326            let (mut handled, mut event_cx) =
327                self.handle_hover_events(&event, &mut invalidated_views, cx);
328
329            for (handler, view_id, position) in mouse_down_out_handlers {
330                event_cx.with_current_view(view_id, |event_cx| handler(position, event_cx))
331            }
332
333            if let Some((mouse_down_region, position)) = mouse_down_region {
334                handled = true;
335                if let Some(mouse_down_callback) = mouse_down_region.mouse_down {
336                    event_cx.with_current_view(mouse_down_region.view_id, |event_cx| {
337                        mouse_down_callback(position, event_cx);
338                    })
339                }
340            }
341
342            if let Some((clicked_region, position, click_count)) = clicked_region {
343                handled = true;
344                if let Some(click_callback) = clicked_region.click {
345                    event_cx.with_current_view(clicked_region.view_id, |event_cx| {
346                        click_callback(position, click_count, event_cx);
347                    })
348                }
349            }
350
351            if let Some((right_mouse_down_region, position)) = right_mouse_down_region {
352                handled = true;
353                if let Some(right_mouse_down_callback) = right_mouse_down_region.right_mouse_down {
354                    event_cx.with_current_view(right_mouse_down_region.view_id, |event_cx| {
355                        right_mouse_down_callback(position, event_cx);
356                    })
357                }
358            }
359
360            if let Some((right_clicked_region, position, click_count)) = right_clicked_region {
361                handled = true;
362                if let Some(right_click_callback) = right_clicked_region.right_click {
363                    event_cx.with_current_view(right_clicked_region.view_id, |event_cx| {
364                        right_click_callback(position, click_count, event_cx);
365                    })
366                }
367            }
368
369            if let Some((dragged_region, delta)) = dragged_region {
370                handled = true;
371                if let Some(drag_callback) = dragged_region.drag {
372                    event_cx.with_current_view(dragged_region.view_id, |event_cx| {
373                        drag_callback(delta, event_cx);
374                    })
375                }
376            }
377
378            if !handled {
379                handled = event_cx.dispatch_event(root_view_id, &event);
380            }
381
382            invalidated_views.extend(event_cx.invalidated_views);
383            let dispatch_directives = event_cx.dispatched_actions;
384
385            for view_id in invalidated_views {
386                cx.notify_view(self.window_id, view_id);
387            }
388
389            let mut dispatch_path = Vec::new();
390            for directive in dispatch_directives {
391                dispatch_path.clear();
392                if let Some(view_id) = directive.dispatcher_view_id {
393                    self.compute_dispatch_path_from(view_id, &mut dispatch_path);
394                }
395                cx.dispatch_action_any(self.window_id, &dispatch_path, directive.action.as_ref());
396            }
397
398            handled
399        } else {
400            false
401        }
402    }
403
404    fn handle_hover_events<'a>(
405        &'a mut self,
406        event: &Event,
407        invalidated_views: &mut Vec<usize>,
408        cx: &'a mut MutableAppContext,
409    ) -> (bool, EventContext<'a>) {
410        let mut unhovered_regions = Vec::new();
411        let mut hovered_regions = Vec::new();
412
413        if let Event::MouseMoved {
414            position,
415            left_mouse_down,
416            ..
417        } = event
418        {
419            if !left_mouse_down {
420                let mut style_to_assign = CursorStyle::Arrow;
421                for region in self.cursor_regions.iter().rev() {
422                    if region.bounds.contains_point(*position) {
423                        style_to_assign = region.style;
424                        break;
425                    }
426                }
427                cx.platform().set_cursor_style(style_to_assign);
428
429                let mut hover_depth = None;
430                for (region, depth) in self.mouse_regions.iter().rev() {
431                    if region.bounds.contains_point(*position)
432                        && hover_depth.map_or(true, |hover_depth| hover_depth == *depth)
433                    {
434                        hover_depth = Some(*depth);
435                        if let Some(region_id) = region.id() {
436                            if !self.hovered_region_ids.contains(&region_id) {
437                                invalidated_views.push(region.view_id);
438                                hovered_regions.push((region.clone(), position));
439                                self.hovered_region_ids.insert(region_id);
440                            }
441                        }
442                    } else {
443                        if let Some(region_id) = region.id() {
444                            if self.hovered_region_ids.contains(&region_id) {
445                                invalidated_views.push(region.view_id);
446                                unhovered_regions.push((region.clone(), position));
447                                self.hovered_region_ids.remove(&region_id);
448                            }
449                        }
450                    }
451                }
452            }
453        }
454
455        let mut event_cx = self.build_event_context(cx);
456        let mut handled = false;
457
458        for (unhovered_region, position) in unhovered_regions {
459            handled = true;
460            if let Some(hover_callback) = unhovered_region.hover {
461                event_cx.with_current_view(unhovered_region.view_id, |event_cx| {
462                    hover_callback(*position, false, event_cx);
463                })
464            }
465        }
466
467        for (hovered_region, position) in hovered_regions {
468            handled = true;
469            if let Some(hover_callback) = hovered_region.hover {
470                event_cx.with_current_view(hovered_region.view_id, |event_cx| {
471                    hover_callback(*position, true, event_cx);
472                })
473            }
474        }
475
476        (handled, event_cx)
477    }
478
479    pub fn build_event_context<'a>(
480        &'a mut self,
481        cx: &'a mut MutableAppContext,
482    ) -> EventContext<'a> {
483        EventContext {
484            rendered_views: &mut self.rendered_views,
485            dispatched_actions: Default::default(),
486            font_cache: &self.font_cache,
487            text_layout_cache: &self.text_layout_cache,
488            view_stack: Default::default(),
489            invalidated_views: Default::default(),
490            notify_count: 0,
491            window_id: self.window_id,
492            app: cx,
493        }
494    }
495
496    pub fn debug_elements(&self, cx: &AppContext) -> Option<json::Value> {
497        let view = cx.root_view(self.window_id)?;
498        Some(json!({
499            "root_view": view.debug_json(cx),
500            "root_element": self.rendered_views.get(&view.id())
501                .map(|root_element| {
502                    root_element.debug(&DebugContext {
503                        rendered_views: &self.rendered_views,
504                        font_cache: &self.font_cache,
505                        app: cx,
506                    })
507                })
508        }))
509    }
510}
511
512pub struct DispatchDirective {
513    pub dispatcher_view_id: Option<usize>,
514    pub action: Box<dyn Action>,
515}
516
517pub struct LayoutContext<'a> {
518    window_id: usize,
519    rendered_views: &'a mut HashMap<usize, ElementBox>,
520    parents: &'a mut HashMap<usize, usize>,
521    view_stack: Vec<usize>,
522    pub font_cache: &'a Arc<FontCache>,
523    pub font_system: Arc<dyn FontSystem>,
524    pub text_layout_cache: &'a TextLayoutCache,
525    pub asset_cache: &'a AssetCache,
526    pub app: &'a mut MutableAppContext,
527    pub refreshing: bool,
528    pub window_size: Vector2F,
529    titlebar_height: f32,
530    hovered_region_ids: HashSet<MouseRegionId>,
531    clicked_region_id: Option<MouseRegionId>,
532    right_clicked_region_id: Option<MouseRegionId>,
533}
534
535impl<'a> LayoutContext<'a> {
536    pub(crate) fn keystrokes_for_action(
537        &self,
538        action: &dyn Action,
539    ) -> Option<SmallVec<[Keystroke; 2]>> {
540        self.app
541            .keystrokes_for_action(self.window_id, &self.view_stack, action)
542    }
543
544    fn layout(&mut self, view_id: usize, constraint: SizeConstraint) -> Vector2F {
545        if let Some(parent_id) = self.view_stack.last() {
546            self.parents.insert(view_id, *parent_id);
547        }
548        self.view_stack.push(view_id);
549        let mut rendered_view = self.rendered_views.remove(&view_id).unwrap();
550        let size = rendered_view.layout(constraint, self);
551        self.rendered_views.insert(view_id, rendered_view);
552        self.view_stack.pop();
553        size
554    }
555
556    pub fn render<F, V, T>(&mut self, handle: &ViewHandle<V>, f: F) -> T
557    where
558        F: FnOnce(&mut V, &mut RenderContext<V>) -> T,
559        V: View,
560    {
561        handle.update(self.app, |view, cx| {
562            let mut render_cx = RenderContext {
563                app: cx,
564                window_id: handle.window_id(),
565                view_id: handle.id(),
566                view_type: PhantomData,
567                titlebar_height: self.titlebar_height,
568                hovered_region_ids: self.hovered_region_ids.clone(),
569                clicked_region_id: self.clicked_region_id,
570                right_clicked_region_id: self.right_clicked_region_id,
571                refreshing: self.refreshing,
572            };
573            f(view, &mut render_cx)
574        })
575    }
576}
577
578impl<'a> Deref for LayoutContext<'a> {
579    type Target = MutableAppContext;
580
581    fn deref(&self) -> &Self::Target {
582        self.app
583    }
584}
585
586impl<'a> DerefMut for LayoutContext<'a> {
587    fn deref_mut(&mut self) -> &mut Self::Target {
588        self.app
589    }
590}
591
592impl<'a> ReadView for LayoutContext<'a> {
593    fn read_view<T: View>(&self, handle: &ViewHandle<T>) -> &T {
594        self.app.read_view(handle)
595    }
596}
597
598impl<'a> ReadModel for LayoutContext<'a> {
599    fn read_model<T: Entity>(&self, handle: &ModelHandle<T>) -> &T {
600        self.app.read_model(handle)
601    }
602}
603
604impl<'a> UpgradeModelHandle for LayoutContext<'a> {
605    fn upgrade_model_handle<T: Entity>(
606        &self,
607        handle: &WeakModelHandle<T>,
608    ) -> Option<ModelHandle<T>> {
609        self.app.upgrade_model_handle(handle)
610    }
611
612    fn model_handle_is_upgradable<T: Entity>(&self, handle: &WeakModelHandle<T>) -> bool {
613        self.app.model_handle_is_upgradable(handle)
614    }
615
616    fn upgrade_any_model_handle(&self, handle: &AnyWeakModelHandle) -> Option<AnyModelHandle> {
617        self.app.upgrade_any_model_handle(handle)
618    }
619}
620
621impl<'a> UpgradeViewHandle for LayoutContext<'a> {
622    fn upgrade_view_handle<T: View>(&self, handle: &WeakViewHandle<T>) -> Option<ViewHandle<T>> {
623        self.app.upgrade_view_handle(handle)
624    }
625
626    fn upgrade_any_view_handle(&self, handle: &crate::AnyWeakViewHandle) -> Option<AnyViewHandle> {
627        self.app.upgrade_any_view_handle(handle)
628    }
629}
630
631pub struct PaintContext<'a> {
632    rendered_views: &'a mut HashMap<usize, ElementBox>,
633    view_stack: Vec<usize>,
634    pub window_size: Vector2F,
635    pub scene: &'a mut Scene,
636    pub font_cache: &'a FontCache,
637    pub text_layout_cache: &'a TextLayoutCache,
638    pub app: &'a AppContext,
639}
640
641impl<'a> PaintContext<'a> {
642    fn paint(&mut self, view_id: usize, origin: Vector2F, visible_bounds: RectF) {
643        if let Some(mut tree) = self.rendered_views.remove(&view_id) {
644            self.view_stack.push(view_id);
645            tree.paint(origin, visible_bounds, self);
646            self.rendered_views.insert(view_id, tree);
647            self.view_stack.pop();
648        }
649    }
650
651    pub fn current_view_id(&self) -> usize {
652        *self.view_stack.last().unwrap()
653    }
654}
655
656impl<'a> Deref for PaintContext<'a> {
657    type Target = AppContext;
658
659    fn deref(&self) -> &Self::Target {
660        self.app
661    }
662}
663
664pub struct EventContext<'a> {
665    rendered_views: &'a mut HashMap<usize, ElementBox>,
666    dispatched_actions: Vec<DispatchDirective>,
667    pub font_cache: &'a FontCache,
668    pub text_layout_cache: &'a TextLayoutCache,
669    pub app: &'a mut MutableAppContext,
670    pub window_id: usize,
671    pub notify_count: usize,
672    view_stack: Vec<usize>,
673    invalidated_views: HashSet<usize>,
674}
675
676impl<'a> EventContext<'a> {
677    fn dispatch_event(&mut self, view_id: usize, event: &Event) -> bool {
678        if let Some(mut element) = self.rendered_views.remove(&view_id) {
679            let result =
680                self.with_current_view(view_id, |this| element.dispatch_event(event, this));
681            self.rendered_views.insert(view_id, element);
682            result
683        } else {
684            false
685        }
686    }
687
688    fn with_current_view<F, T>(&mut self, view_id: usize, f: F) -> T
689    where
690        F: FnOnce(&mut Self) -> T,
691    {
692        self.view_stack.push(view_id);
693        let result = f(self);
694        self.view_stack.pop();
695        result
696    }
697
698    pub fn window_id(&self) -> usize {
699        self.window_id
700    }
701
702    pub fn view_id(&self) -> Option<usize> {
703        self.view_stack.last().copied()
704    }
705
706    pub fn is_parent_view_focused(&self) -> bool {
707        if let Some(parent_view_id) = self.view_stack.last() {
708            self.app.focused_view_id(self.window_id) == Some(*parent_view_id)
709        } else {
710            false
711        }
712    }
713
714    pub fn focus_parent_view(&mut self) {
715        if let Some(parent_view_id) = self.view_stack.last() {
716            self.app.focus(self.window_id, Some(*parent_view_id))
717        }
718    }
719
720    pub fn dispatch_any_action(&mut self, action: Box<dyn Action>) {
721        self.dispatched_actions.push(DispatchDirective {
722            dispatcher_view_id: self.view_stack.last().copied(),
723            action,
724        });
725    }
726
727    pub fn dispatch_action<A: Action>(&mut self, action: A) {
728        self.dispatch_any_action(Box::new(action));
729    }
730
731    pub fn notify(&mut self) {
732        self.notify_count += 1;
733        if let Some(view_id) = self.view_stack.last() {
734            self.invalidated_views.insert(*view_id);
735        }
736    }
737
738    pub fn notify_count(&self) -> usize {
739        self.notify_count
740    }
741}
742
743impl<'a> Deref for EventContext<'a> {
744    type Target = MutableAppContext;
745
746    fn deref(&self) -> &Self::Target {
747        self.app
748    }
749}
750
751impl<'a> DerefMut for EventContext<'a> {
752    fn deref_mut(&mut self) -> &mut Self::Target {
753        self.app
754    }
755}
756
757pub struct DebugContext<'a> {
758    rendered_views: &'a HashMap<usize, ElementBox>,
759    pub font_cache: &'a FontCache,
760    pub app: &'a AppContext,
761}
762
763#[derive(Clone, Copy, Debug, Eq, PartialEq)]
764pub enum Axis {
765    Horizontal,
766    Vertical,
767}
768
769impl Axis {
770    pub fn invert(self) -> Self {
771        match self {
772            Self::Horizontal => Self::Vertical,
773            Self::Vertical => Self::Horizontal,
774        }
775    }
776}
777
778impl ToJson for Axis {
779    fn to_json(&self) -> serde_json::Value {
780        match self {
781            Axis::Horizontal => json!("horizontal"),
782            Axis::Vertical => json!("vertical"),
783        }
784    }
785}
786
787pub trait Vector2FExt {
788    fn along(self, axis: Axis) -> f32;
789}
790
791impl Vector2FExt for Vector2F {
792    fn along(self, axis: Axis) -> f32 {
793        match axis {
794            Axis::Horizontal => self.x(),
795            Axis::Vertical => self.y(),
796        }
797    }
798}
799
800#[derive(Copy, Clone, Debug)]
801pub struct SizeConstraint {
802    pub min: Vector2F,
803    pub max: Vector2F,
804}
805
806impl SizeConstraint {
807    pub fn new(min: Vector2F, max: Vector2F) -> Self {
808        Self { min, max }
809    }
810
811    pub fn strict(size: Vector2F) -> Self {
812        Self {
813            min: size,
814            max: size,
815        }
816    }
817
818    pub fn strict_along(axis: Axis, max: f32) -> Self {
819        match axis {
820            Axis::Horizontal => Self {
821                min: vec2f(max, 0.0),
822                max: vec2f(max, f32::INFINITY),
823            },
824            Axis::Vertical => Self {
825                min: vec2f(0.0, max),
826                max: vec2f(f32::INFINITY, max),
827            },
828        }
829    }
830
831    pub fn max_along(&self, axis: Axis) -> f32 {
832        match axis {
833            Axis::Horizontal => self.max.x(),
834            Axis::Vertical => self.max.y(),
835        }
836    }
837
838    pub fn min_along(&self, axis: Axis) -> f32 {
839        match axis {
840            Axis::Horizontal => self.min.x(),
841            Axis::Vertical => self.min.y(),
842        }
843    }
844
845    pub fn constrain(&self, size: Vector2F) -> Vector2F {
846        vec2f(
847            size.x().min(self.max.x()).max(self.min.x()),
848            size.y().min(self.max.y()).max(self.min.y()),
849        )
850    }
851}
852
853impl Default for SizeConstraint {
854    fn default() -> Self {
855        SizeConstraint {
856            min: Vector2F::zero(),
857            max: Vector2F::splat(f32::INFINITY),
858        }
859    }
860}
861
862impl ToJson for SizeConstraint {
863    fn to_json(&self) -> serde_json::Value {
864        json!({
865            "min": self.min.to_json(),
866            "max": self.max.to_json(),
867        })
868    }
869}
870
871pub struct ChildView {
872    view: AnyViewHandle,
873}
874
875impl ChildView {
876    pub fn new(view: impl Into<AnyViewHandle>) -> Self {
877        Self { view: view.into() }
878    }
879}
880
881impl Element for ChildView {
882    type LayoutState = ();
883    type PaintState = ();
884
885    fn layout(
886        &mut self,
887        constraint: SizeConstraint,
888        cx: &mut LayoutContext,
889    ) -> (Vector2F, Self::LayoutState) {
890        let size = cx.layout(self.view.id(), constraint);
891        (size, ())
892    }
893
894    fn paint(
895        &mut self,
896        bounds: RectF,
897        visible_bounds: RectF,
898        _: &mut Self::LayoutState,
899        cx: &mut PaintContext,
900    ) -> Self::PaintState {
901        cx.paint(self.view.id(), bounds.origin(), visible_bounds);
902    }
903
904    fn dispatch_event(
905        &mut self,
906        event: &Event,
907        _: RectF,
908        _: RectF,
909        _: &mut Self::LayoutState,
910        _: &mut Self::PaintState,
911        cx: &mut EventContext,
912    ) -> bool {
913        cx.dispatch_event(self.view.id(), event)
914    }
915
916    fn debug(
917        &self,
918        bounds: RectF,
919        _: &Self::LayoutState,
920        _: &Self::PaintState,
921        cx: &DebugContext,
922    ) -> serde_json::Value {
923        json!({
924            "type": "ChildView",
925            "view_id": self.view.id(),
926            "bounds": bounds.to_json(),
927            "view": self.view.debug_json(cx.app),
928            "child": if let Some(view) = cx.rendered_views.get(&self.view.id()) {
929                view.debug(cx)
930            } else {
931                json!(null)
932            }
933        })
934    }
935}