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 { position } => {
298                    if let Some((clicked_region, prev_drag_position)) = self
299                        .clicked_region
300                        .as_ref()
301                        .zip(self.prev_drag_position.as_mut())
302                    {
303                        dragged_region =
304                            Some((clicked_region.clone(), position - *prev_drag_position));
305                        *prev_drag_position = position;
306                    }
307
308                    self.last_mouse_moved_event = Some(Event::MouseMoved {
309                        position,
310                        left_mouse_down: true,
311                    });
312                }
313                _ => {}
314            }
315
316            let (mut handled, mut event_cx) =
317                self.handle_hover_events(&event, &mut invalidated_views, cx);
318
319            for (handler, view_id, position) in mouse_down_out_handlers {
320                event_cx.with_current_view(view_id, |event_cx| handler(position, event_cx))
321            }
322
323            if let Some((mouse_down_region, position)) = mouse_down_region {
324                handled = true;
325                if let Some(mouse_down_callback) = mouse_down_region.mouse_down {
326                    event_cx.with_current_view(mouse_down_region.view_id, |event_cx| {
327                        mouse_down_callback(position, event_cx);
328                    })
329                }
330            }
331
332            if let Some((clicked_region, position, click_count)) = clicked_region {
333                handled = true;
334                if let Some(click_callback) = clicked_region.click {
335                    event_cx.with_current_view(clicked_region.view_id, |event_cx| {
336                        click_callback(position, click_count, event_cx);
337                    })
338                }
339            }
340
341            if let Some((right_mouse_down_region, position)) = right_mouse_down_region {
342                handled = true;
343                if let Some(right_mouse_down_callback) = right_mouse_down_region.right_mouse_down {
344                    event_cx.with_current_view(right_mouse_down_region.view_id, |event_cx| {
345                        right_mouse_down_callback(position, event_cx);
346                    })
347                }
348            }
349
350            if let Some((right_clicked_region, position, click_count)) = right_clicked_region {
351                handled = true;
352                if let Some(right_click_callback) = right_clicked_region.right_click {
353                    event_cx.with_current_view(right_clicked_region.view_id, |event_cx| {
354                        right_click_callback(position, click_count, event_cx);
355                    })
356                }
357            }
358
359            if let Some((dragged_region, delta)) = dragged_region {
360                handled = true;
361                if let Some(drag_callback) = dragged_region.drag {
362                    event_cx.with_current_view(dragged_region.view_id, |event_cx| {
363                        drag_callback(delta, event_cx);
364                    })
365                }
366            }
367
368            if !handled {
369                handled = event_cx.dispatch_event(root_view_id, &event);
370            }
371
372            invalidated_views.extend(event_cx.invalidated_views);
373            let dispatch_directives = event_cx.dispatched_actions;
374
375            for view_id in invalidated_views {
376                cx.notify_view(self.window_id, view_id);
377            }
378
379            let mut dispatch_path = Vec::new();
380            for directive in dispatch_directives {
381                dispatch_path.clear();
382                if let Some(view_id) = directive.dispatcher_view_id {
383                    self.compute_dispatch_path_from(view_id, &mut dispatch_path);
384                }
385                cx.dispatch_action_any(self.window_id, &dispatch_path, directive.action.as_ref());
386            }
387
388            handled
389        } else {
390            false
391        }
392    }
393
394    fn handle_hover_events<'a>(
395        &'a mut self,
396        event: &Event,
397        invalidated_views: &mut Vec<usize>,
398        cx: &'a mut MutableAppContext,
399    ) -> (bool, EventContext<'a>) {
400        let mut unhovered_regions = Vec::new();
401        let mut hovered_regions = Vec::new();
402
403        if let Event::MouseMoved {
404            position,
405            left_mouse_down,
406        } = event
407        {
408            if !left_mouse_down {
409                let mut style_to_assign = CursorStyle::Arrow;
410                for region in self.cursor_regions.iter().rev() {
411                    if region.bounds.contains_point(*position) {
412                        style_to_assign = region.style;
413                        break;
414                    }
415                }
416                cx.platform().set_cursor_style(style_to_assign);
417
418                let mut hover_depth = None;
419                for (region, depth) in self.mouse_regions.iter().rev() {
420                    if region.bounds.contains_point(*position)
421                        && hover_depth.map_or(true, |hover_depth| hover_depth == *depth)
422                    {
423                        hover_depth = Some(*depth);
424                        if let Some(region_id) = region.id() {
425                            if !self.hovered_region_ids.contains(&region_id) {
426                                invalidated_views.push(region.view_id);
427                                hovered_regions.push((region.clone(), position));
428                                self.hovered_region_ids.insert(region_id);
429                            }
430                        }
431                    } else {
432                        if let Some(region_id) = region.id() {
433                            if self.hovered_region_ids.contains(&region_id) {
434                                invalidated_views.push(region.view_id);
435                                unhovered_regions.push((region.clone(), position));
436                                self.hovered_region_ids.remove(&region_id);
437                            }
438                        }
439                    }
440                }
441            }
442        }
443
444        let mut event_cx = self.build_event_context(cx);
445        let mut handled = false;
446
447        for (unhovered_region, position) in unhovered_regions {
448            handled = true;
449            if let Some(hover_callback) = unhovered_region.hover {
450                event_cx.with_current_view(unhovered_region.view_id, |event_cx| {
451                    hover_callback(*position, false, event_cx);
452                })
453            }
454        }
455
456        for (hovered_region, position) in hovered_regions {
457            handled = true;
458            if let Some(hover_callback) = hovered_region.hover {
459                event_cx.with_current_view(hovered_region.view_id, |event_cx| {
460                    hover_callback(*position, true, event_cx);
461                })
462            }
463        }
464
465        (handled, event_cx)
466    }
467
468    pub fn build_event_context<'a>(
469        &'a mut self,
470        cx: &'a mut MutableAppContext,
471    ) -> EventContext<'a> {
472        EventContext {
473            rendered_views: &mut self.rendered_views,
474            dispatched_actions: Default::default(),
475            font_cache: &self.font_cache,
476            text_layout_cache: &self.text_layout_cache,
477            view_stack: Default::default(),
478            invalidated_views: Default::default(),
479            notify_count: 0,
480            window_id: self.window_id,
481            app: cx,
482        }
483    }
484
485    pub fn debug_elements(&self, cx: &AppContext) -> Option<json::Value> {
486        let view = cx.root_view(self.window_id)?;
487        Some(json!({
488            "root_view": view.debug_json(cx),
489            "root_element": self.rendered_views.get(&view.id())
490                .map(|root_element| {
491                    root_element.debug(&DebugContext {
492                        rendered_views: &self.rendered_views,
493                        font_cache: &self.font_cache,
494                        app: cx,
495                    })
496                })
497        }))
498    }
499}
500
501pub struct DispatchDirective {
502    pub dispatcher_view_id: Option<usize>,
503    pub action: Box<dyn Action>,
504}
505
506pub struct LayoutContext<'a> {
507    window_id: usize,
508    rendered_views: &'a mut HashMap<usize, ElementBox>,
509    parents: &'a mut HashMap<usize, usize>,
510    view_stack: Vec<usize>,
511    pub font_cache: &'a Arc<FontCache>,
512    pub font_system: Arc<dyn FontSystem>,
513    pub text_layout_cache: &'a TextLayoutCache,
514    pub asset_cache: &'a AssetCache,
515    pub app: &'a mut MutableAppContext,
516    pub refreshing: bool,
517    pub window_size: Vector2F,
518    titlebar_height: f32,
519    hovered_region_ids: HashSet<MouseRegionId>,
520    clicked_region_id: Option<MouseRegionId>,
521    right_clicked_region_id: Option<MouseRegionId>,
522}
523
524impl<'a> LayoutContext<'a> {
525    pub(crate) fn keystrokes_for_action(
526        &self,
527        action: &dyn Action,
528    ) -> Option<SmallVec<[Keystroke; 2]>> {
529        self.app
530            .keystrokes_for_action(self.window_id, &self.view_stack, action)
531    }
532
533    fn layout(&mut self, view_id: usize, constraint: SizeConstraint) -> Vector2F {
534        if let Some(parent_id) = self.view_stack.last() {
535            self.parents.insert(view_id, *parent_id);
536        }
537        self.view_stack.push(view_id);
538        let mut rendered_view = self.rendered_views.remove(&view_id).unwrap();
539        let size = rendered_view.layout(constraint, self);
540        self.rendered_views.insert(view_id, rendered_view);
541        self.view_stack.pop();
542        size
543    }
544
545    pub fn render<F, V, T>(&mut self, handle: &ViewHandle<V>, f: F) -> T
546    where
547        F: FnOnce(&mut V, &mut RenderContext<V>) -> T,
548        V: View,
549    {
550        handle.update(self.app, |view, cx| {
551            let mut render_cx = RenderContext {
552                app: cx,
553                window_id: handle.window_id(),
554                view_id: handle.id(),
555                view_type: PhantomData,
556                titlebar_height: self.titlebar_height,
557                hovered_region_ids: self.hovered_region_ids.clone(),
558                clicked_region_id: self.clicked_region_id,
559                right_clicked_region_id: self.right_clicked_region_id,
560                refreshing: self.refreshing,
561            };
562            f(view, &mut render_cx)
563        })
564    }
565}
566
567impl<'a> Deref for LayoutContext<'a> {
568    type Target = MutableAppContext;
569
570    fn deref(&self) -> &Self::Target {
571        self.app
572    }
573}
574
575impl<'a> DerefMut for LayoutContext<'a> {
576    fn deref_mut(&mut self) -> &mut Self::Target {
577        self.app
578    }
579}
580
581impl<'a> ReadView for LayoutContext<'a> {
582    fn read_view<T: View>(&self, handle: &ViewHandle<T>) -> &T {
583        self.app.read_view(handle)
584    }
585}
586
587impl<'a> ReadModel for LayoutContext<'a> {
588    fn read_model<T: Entity>(&self, handle: &ModelHandle<T>) -> &T {
589        self.app.read_model(handle)
590    }
591}
592
593impl<'a> UpgradeModelHandle for LayoutContext<'a> {
594    fn upgrade_model_handle<T: Entity>(
595        &self,
596        handle: &WeakModelHandle<T>,
597    ) -> Option<ModelHandle<T>> {
598        self.app.upgrade_model_handle(handle)
599    }
600
601    fn model_handle_is_upgradable<T: Entity>(&self, handle: &WeakModelHandle<T>) -> bool {
602        self.app.model_handle_is_upgradable(handle)
603    }
604
605    fn upgrade_any_model_handle(&self, handle: &AnyWeakModelHandle) -> Option<AnyModelHandle> {
606        self.app.upgrade_any_model_handle(handle)
607    }
608}
609
610impl<'a> UpgradeViewHandle for LayoutContext<'a> {
611    fn upgrade_view_handle<T: View>(&self, handle: &WeakViewHandle<T>) -> Option<ViewHandle<T>> {
612        self.app.upgrade_view_handle(handle)
613    }
614
615    fn upgrade_any_view_handle(&self, handle: &crate::AnyWeakViewHandle) -> Option<AnyViewHandle> {
616        self.app.upgrade_any_view_handle(handle)
617    }
618}
619
620pub struct PaintContext<'a> {
621    rendered_views: &'a mut HashMap<usize, ElementBox>,
622    view_stack: Vec<usize>,
623    pub window_size: Vector2F,
624    pub scene: &'a mut Scene,
625    pub font_cache: &'a FontCache,
626    pub text_layout_cache: &'a TextLayoutCache,
627    pub app: &'a AppContext,
628}
629
630impl<'a> PaintContext<'a> {
631    fn paint(&mut self, view_id: usize, origin: Vector2F, visible_bounds: RectF) {
632        if let Some(mut tree) = self.rendered_views.remove(&view_id) {
633            self.view_stack.push(view_id);
634            tree.paint(origin, visible_bounds, self);
635            self.rendered_views.insert(view_id, tree);
636            self.view_stack.pop();
637        }
638    }
639
640    pub fn current_view_id(&self) -> usize {
641        *self.view_stack.last().unwrap()
642    }
643}
644
645impl<'a> Deref for PaintContext<'a> {
646    type Target = AppContext;
647
648    fn deref(&self) -> &Self::Target {
649        self.app
650    }
651}
652
653pub struct EventContext<'a> {
654    rendered_views: &'a mut HashMap<usize, ElementBox>,
655    dispatched_actions: Vec<DispatchDirective>,
656    pub font_cache: &'a FontCache,
657    pub text_layout_cache: &'a TextLayoutCache,
658    pub app: &'a mut MutableAppContext,
659    pub window_id: usize,
660    pub notify_count: usize,
661    view_stack: Vec<usize>,
662    invalidated_views: HashSet<usize>,
663}
664
665impl<'a> EventContext<'a> {
666    fn dispatch_event(&mut self, view_id: usize, event: &Event) -> bool {
667        if let Some(mut element) = self.rendered_views.remove(&view_id) {
668            let result =
669                self.with_current_view(view_id, |this| element.dispatch_event(event, this));
670            self.rendered_views.insert(view_id, element);
671            result
672        } else {
673            false
674        }
675    }
676
677    fn with_current_view<F, T>(&mut self, view_id: usize, f: F) -> T
678    where
679        F: FnOnce(&mut Self) -> T,
680    {
681        self.view_stack.push(view_id);
682        let result = f(self);
683        self.view_stack.pop();
684        result
685    }
686
687    pub fn window_id(&self) -> usize {
688        self.window_id
689    }
690
691    pub fn view_id(&self) -> Option<usize> {
692        self.view_stack.last().copied()
693    }
694
695    pub fn dispatch_any_action(&mut self, action: Box<dyn Action>) {
696        self.dispatched_actions.push(DispatchDirective {
697            dispatcher_view_id: self.view_stack.last().copied(),
698            action,
699        });
700    }
701
702    pub fn dispatch_action<A: Action>(&mut self, action: A) {
703        self.dispatch_any_action(Box::new(action));
704    }
705
706    pub fn notify(&mut self) {
707        self.notify_count += 1;
708        if let Some(view_id) = self.view_stack.last() {
709            self.invalidated_views.insert(*view_id);
710        }
711    }
712
713    pub fn notify_count(&self) -> usize {
714        self.notify_count
715    }
716}
717
718impl<'a> Deref for EventContext<'a> {
719    type Target = MutableAppContext;
720
721    fn deref(&self) -> &Self::Target {
722        self.app
723    }
724}
725
726impl<'a> DerefMut for EventContext<'a> {
727    fn deref_mut(&mut self) -> &mut Self::Target {
728        self.app
729    }
730}
731
732pub struct DebugContext<'a> {
733    rendered_views: &'a HashMap<usize, ElementBox>,
734    pub font_cache: &'a FontCache,
735    pub app: &'a AppContext,
736}
737
738#[derive(Clone, Copy, Debug, Eq, PartialEq)]
739pub enum Axis {
740    Horizontal,
741    Vertical,
742}
743
744impl Axis {
745    pub fn invert(self) -> Self {
746        match self {
747            Self::Horizontal => Self::Vertical,
748            Self::Vertical => Self::Horizontal,
749        }
750    }
751}
752
753impl ToJson for Axis {
754    fn to_json(&self) -> serde_json::Value {
755        match self {
756            Axis::Horizontal => json!("horizontal"),
757            Axis::Vertical => json!("vertical"),
758        }
759    }
760}
761
762pub trait Vector2FExt {
763    fn along(self, axis: Axis) -> f32;
764}
765
766impl Vector2FExt for Vector2F {
767    fn along(self, axis: Axis) -> f32 {
768        match axis {
769            Axis::Horizontal => self.x(),
770            Axis::Vertical => self.y(),
771        }
772    }
773}
774
775#[derive(Copy, Clone, Debug)]
776pub struct SizeConstraint {
777    pub min: Vector2F,
778    pub max: Vector2F,
779}
780
781impl SizeConstraint {
782    pub fn new(min: Vector2F, max: Vector2F) -> Self {
783        Self { min, max }
784    }
785
786    pub fn strict(size: Vector2F) -> Self {
787        Self {
788            min: size,
789            max: size,
790        }
791    }
792
793    pub fn strict_along(axis: Axis, max: f32) -> Self {
794        match axis {
795            Axis::Horizontal => Self {
796                min: vec2f(max, 0.0),
797                max: vec2f(max, f32::INFINITY),
798            },
799            Axis::Vertical => Self {
800                min: vec2f(0.0, max),
801                max: vec2f(f32::INFINITY, max),
802            },
803        }
804    }
805
806    pub fn max_along(&self, axis: Axis) -> f32 {
807        match axis {
808            Axis::Horizontal => self.max.x(),
809            Axis::Vertical => self.max.y(),
810        }
811    }
812
813    pub fn min_along(&self, axis: Axis) -> f32 {
814        match axis {
815            Axis::Horizontal => self.min.x(),
816            Axis::Vertical => self.min.y(),
817        }
818    }
819
820    pub fn constrain(&self, size: Vector2F) -> Vector2F {
821        vec2f(
822            size.x().min(self.max.x()).max(self.min.x()),
823            size.y().min(self.max.y()).max(self.min.y()),
824        )
825    }
826}
827
828impl Default for SizeConstraint {
829    fn default() -> Self {
830        SizeConstraint {
831            min: Vector2F::zero(),
832            max: Vector2F::splat(f32::INFINITY),
833        }
834    }
835}
836
837impl ToJson for SizeConstraint {
838    fn to_json(&self) -> serde_json::Value {
839        json!({
840            "min": self.min.to_json(),
841            "max": self.max.to_json(),
842        })
843    }
844}
845
846pub struct ChildView {
847    view: AnyViewHandle,
848}
849
850impl ChildView {
851    pub fn new(view: impl Into<AnyViewHandle>) -> Self {
852        Self { view: view.into() }
853    }
854}
855
856impl Element for ChildView {
857    type LayoutState = ();
858    type PaintState = ();
859
860    fn layout(
861        &mut self,
862        constraint: SizeConstraint,
863        cx: &mut LayoutContext,
864    ) -> (Vector2F, Self::LayoutState) {
865        let size = cx.layout(self.view.id(), constraint);
866        (size, ())
867    }
868
869    fn paint(
870        &mut self,
871        bounds: RectF,
872        visible_bounds: RectF,
873        _: &mut Self::LayoutState,
874        cx: &mut PaintContext,
875    ) -> Self::PaintState {
876        cx.paint(self.view.id(), bounds.origin(), visible_bounds);
877    }
878
879    fn dispatch_event(
880        &mut self,
881        event: &Event,
882        _: RectF,
883        _: RectF,
884        _: &mut Self::LayoutState,
885        _: &mut Self::PaintState,
886        cx: &mut EventContext,
887    ) -> bool {
888        cx.dispatch_event(self.view.id(), event)
889    }
890
891    fn debug(
892        &self,
893        bounds: RectF,
894        _: &Self::LayoutState,
895        _: &Self::PaintState,
896        cx: &DebugContext,
897    ) -> serde_json::Value {
898        json!({
899            "type": "ChildView",
900            "view_id": self.view.id(),
901            "bounds": bounds.to_json(),
902            "view": self.view.debug_json(cx.app),
903            "child": if let Some(view) = cx.rendered_views.get(&self.view.id()) {
904                view.debug(cx)
905            } else {
906                json!(null)
907            }
908        })
909    }
910}