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, MouseRegionEvent},
 10    text_layout::TextLayoutCache,
 11    Action, AnyModelHandle, AnyViewHandle, AnyWeakModelHandle, AssetCache, ElementBox, Entity,
 12    FontSystem, ModelHandle, MouseButtonEvent, MouseMovedEvent, MouseRegion, MouseRegionId,
 13    ReadModel, ReadView, RenderContext, RenderParams, Scene, UpgradeModelHandle, UpgradeViewHandle,
 14    View, ViewHandle, WeakModelHandle, 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 dragged_region = None;
234
235            match &event {
236                Event::MouseDown(
237                    e @ MouseButtonEvent {
238                        position, button, ..
239                    },
240                ) => {
241                    let mut hit = false;
242                    for (region, _) in self.mouse_regions.iter().rev() {
243                        if region.bounds.contains_point(*position) {
244                            if !hit {
245                                hit = true;
246                                invalidated_views.push(region.view_id);
247                                mouse_down_region =
248                                    Some((region.clone(), MouseRegionEvent::Down(e.clone())));
249                                self.clicked_region = Some(region.clone());
250                                self.prev_drag_position = Some(*position);
251                            }
252                        } else if let Some(handler) = region
253                            .handlers
254                            .get(&(MouseRegionEvent::down_out_disc(), Some(*button)))
255                        {
256                            mouse_down_out_handlers.push((
257                                handler,
258                                region.view_id,
259                                MouseRegionEvent::DownOut(e.clone()),
260                            ));
261                        }
262                    }
263                }
264                Event::MouseUp(e @ MouseButtonEvent { position, .. }) => {
265                    self.prev_drag_position.take();
266                    if let Some(region) = self.clicked_region.take() {
267                        invalidated_views.push(region.view_id);
268                        if region.bounds.contains_point(*position) {
269                            clicked_region = Some((region, MouseRegionEvent::Click(e.clone())));
270                        }
271                    }
272                }
273                Event::MouseMoved(e @ MouseMovedEvent { position, .. }) => {
274                    if let Some((clicked_region, prev_drag_position)) = self
275                        .clicked_region
276                        .as_ref()
277                        .zip(self.prev_drag_position.as_mut())
278                    {
279                        dragged_region = Some((
280                            clicked_region.clone(),
281                            MouseRegionEvent::Drag(*prev_drag_position, e.clone()),
282                        ));
283                        *prev_drag_position = *position;
284                    }
285
286                    self.last_mouse_moved_event = Some(event.clone());
287                }
288                _ => {}
289            }
290
291            let (mut handled, mut event_cx) =
292                self.handle_hover_events(&event, &mut invalidated_views, cx);
293
294            for (handler, view_id, region_event) in mouse_down_out_handlers {
295                event_cx.with_current_view(view_id, |event_cx| handler(region_event, event_cx))
296            }
297
298            if let Some((mouse_down_region, region_event)) = mouse_down_region {
299                handled = true;
300                if let Some(mouse_down_callback) =
301                    mouse_down_region.handlers.get(&region_event.handler_key())
302                {
303                    event_cx.with_current_view(mouse_down_region.view_id, |event_cx| {
304                        mouse_down_callback(region_event, event_cx);
305                    })
306                }
307            }
308
309            if let Some((clicked_region, region_event)) = clicked_region {
310                handled = true;
311                if let Some(click_callback) =
312                    clicked_region.handlers.get(&region_event.handler_key())
313                {
314                    event_cx.with_current_view(clicked_region.view_id, |event_cx| {
315                        click_callback(region_event, event_cx);
316                    })
317                }
318            }
319
320            if let Some((dragged_region, region_event)) = dragged_region {
321                handled = true;
322                if let Some(drag_callback) =
323                    dragged_region.handlers.get(&region_event.handler_key())
324                {
325                    event_cx.with_current_view(dragged_region.view_id, |event_cx| {
326                        drag_callback(region_event, event_cx);
327                    })
328                }
329            }
330
331            if !handled {
332                handled = event_cx.dispatch_event(root_view_id, &event);
333            }
334
335            invalidated_views.extend(event_cx.invalidated_views);
336            let dispatch_directives = event_cx.dispatched_actions;
337
338            for view_id in invalidated_views {
339                cx.notify_view(self.window_id, view_id);
340            }
341
342            let mut dispatch_path = Vec::new();
343            for directive in dispatch_directives {
344                dispatch_path.clear();
345                if let Some(view_id) = directive.dispatcher_view_id {
346                    self.compute_dispatch_path_from(view_id, &mut dispatch_path);
347                }
348                cx.dispatch_action_any(self.window_id, &dispatch_path, directive.action.as_ref());
349            }
350
351            handled
352        } else {
353            false
354        }
355    }
356
357    fn handle_hover_events<'a>(
358        &'a mut self,
359        event: &Event,
360        invalidated_views: &mut Vec<usize>,
361        cx: &'a mut MutableAppContext,
362    ) -> (bool, EventContext<'a>) {
363        let mut hover_regions = Vec::new();
364        // let mut unhovered_regions = Vec::new();
365        // let mut hovered_regions = Vec::new();
366
367        if let Event::MouseMoved(
368            e @ MouseMovedEvent {
369                position,
370                pressed_button,
371                ..
372            },
373        ) = event
374        {
375            if let None = pressed_button {
376                let mut style_to_assign = CursorStyle::Arrow;
377                for region in self.cursor_regions.iter().rev() {
378                    if region.bounds.contains_point(*position) {
379                        style_to_assign = region.style;
380                        break;
381                    }
382                }
383                cx.platform().set_cursor_style(style_to_assign);
384
385                let mut hover_depth = None;
386                for (region, depth) in self.mouse_regions.iter().rev() {
387                    if region.bounds.contains_point(*position)
388                        && hover_depth.map_or(true, |hover_depth| hover_depth == *depth)
389                    {
390                        hover_depth = Some(*depth);
391                        if let Some(region_id) = region.id() {
392                            if !self.hovered_region_ids.contains(&region_id) {
393                                invalidated_views.push(region.view_id);
394                                hover_regions.push((
395                                    region.clone(),
396                                    MouseRegionEvent::Hover(true, e.clone()),
397                                ));
398                                self.hovered_region_ids.insert(region_id);
399                            }
400                        }
401                    } else {
402                        if let Some(region_id) = region.id() {
403                            if self.hovered_region_ids.contains(&region_id) {
404                                invalidated_views.push(region.view_id);
405                                hover_regions.push((
406                                    region.clone(),
407                                    MouseRegionEvent::Hover(false, e.clone()),
408                                ));
409                                self.hovered_region_ids.remove(&region_id);
410                            }
411                        }
412                    }
413                }
414            }
415        }
416
417        let mut event_cx = self.build_event_context(cx);
418        let mut handled = false;
419
420        for (hover_region, region_event) in hover_regions {
421            handled = true;
422            if let Some(hover_callback) = hover_region.handlers.get(&region_event.handler_key()) {
423                event_cx.with_current_view(hover_region.view_id, |event_cx| {
424                    hover_callback(region_event, event_cx);
425                })
426            }
427        }
428
429        (handled, event_cx)
430    }
431
432    pub fn build_event_context<'a>(
433        &'a mut self,
434        cx: &'a mut MutableAppContext,
435    ) -> EventContext<'a> {
436        EventContext {
437            rendered_views: &mut self.rendered_views,
438            dispatched_actions: Default::default(),
439            font_cache: &self.font_cache,
440            text_layout_cache: &self.text_layout_cache,
441            view_stack: Default::default(),
442            invalidated_views: Default::default(),
443            notify_count: 0,
444            window_id: self.window_id,
445            app: cx,
446        }
447    }
448
449    pub fn debug_elements(&self, cx: &AppContext) -> Option<json::Value> {
450        let view = cx.root_view(self.window_id)?;
451        Some(json!({
452            "root_view": view.debug_json(cx),
453            "root_element": self.rendered_views.get(&view.id())
454                .map(|root_element| {
455                    root_element.debug(&DebugContext {
456                        rendered_views: &self.rendered_views,
457                        font_cache: &self.font_cache,
458                        app: cx,
459                    })
460                })
461        }))
462    }
463}
464
465pub struct DispatchDirective {
466    pub dispatcher_view_id: Option<usize>,
467    pub action: Box<dyn Action>,
468}
469
470pub struct LayoutContext<'a> {
471    window_id: usize,
472    rendered_views: &'a mut HashMap<usize, ElementBox>,
473    parents: &'a mut HashMap<usize, usize>,
474    view_stack: Vec<usize>,
475    pub font_cache: &'a Arc<FontCache>,
476    pub font_system: Arc<dyn FontSystem>,
477    pub text_layout_cache: &'a TextLayoutCache,
478    pub asset_cache: &'a AssetCache,
479    pub app: &'a mut MutableAppContext,
480    pub refreshing: bool,
481    pub window_size: Vector2F,
482    titlebar_height: f32,
483    hovered_region_ids: HashSet<MouseRegionId>,
484    clicked_region_id: Option<MouseRegionId>,
485    right_clicked_region_id: Option<MouseRegionId>,
486}
487
488impl<'a> LayoutContext<'a> {
489    pub(crate) fn keystrokes_for_action(
490        &self,
491        action: &dyn Action,
492    ) -> Option<SmallVec<[Keystroke; 2]>> {
493        self.app
494            .keystrokes_for_action(self.window_id, &self.view_stack, action)
495    }
496
497    fn layout(&mut self, view_id: usize, constraint: SizeConstraint) -> Vector2F {
498        if let Some(parent_id) = self.view_stack.last() {
499            self.parents.insert(view_id, *parent_id);
500        }
501        self.view_stack.push(view_id);
502        let mut rendered_view = self.rendered_views.remove(&view_id).unwrap();
503        let size = rendered_view.layout(constraint, self);
504        self.rendered_views.insert(view_id, rendered_view);
505        self.view_stack.pop();
506        size
507    }
508
509    pub fn render<F, V, T>(&mut self, handle: &ViewHandle<V>, f: F) -> T
510    where
511        F: FnOnce(&mut V, &mut RenderContext<V>) -> T,
512        V: View,
513    {
514        handle.update(self.app, |view, cx| {
515            let mut render_cx = RenderContext {
516                app: cx,
517                window_id: handle.window_id(),
518                view_id: handle.id(),
519                view_type: PhantomData,
520                titlebar_height: self.titlebar_height,
521                hovered_region_ids: self.hovered_region_ids.clone(),
522                clicked_region_id: self.clicked_region_id,
523                right_clicked_region_id: self.right_clicked_region_id,
524                refreshing: self.refreshing,
525            };
526            f(view, &mut render_cx)
527        })
528    }
529}
530
531impl<'a> Deref for LayoutContext<'a> {
532    type Target = MutableAppContext;
533
534    fn deref(&self) -> &Self::Target {
535        self.app
536    }
537}
538
539impl<'a> DerefMut for LayoutContext<'a> {
540    fn deref_mut(&mut self) -> &mut Self::Target {
541        self.app
542    }
543}
544
545impl<'a> ReadView for LayoutContext<'a> {
546    fn read_view<T: View>(&self, handle: &ViewHandle<T>) -> &T {
547        self.app.read_view(handle)
548    }
549}
550
551impl<'a> ReadModel for LayoutContext<'a> {
552    fn read_model<T: Entity>(&self, handle: &ModelHandle<T>) -> &T {
553        self.app.read_model(handle)
554    }
555}
556
557impl<'a> UpgradeModelHandle for LayoutContext<'a> {
558    fn upgrade_model_handle<T: Entity>(
559        &self,
560        handle: &WeakModelHandle<T>,
561    ) -> Option<ModelHandle<T>> {
562        self.app.upgrade_model_handle(handle)
563    }
564
565    fn model_handle_is_upgradable<T: Entity>(&self, handle: &WeakModelHandle<T>) -> bool {
566        self.app.model_handle_is_upgradable(handle)
567    }
568
569    fn upgrade_any_model_handle(&self, handle: &AnyWeakModelHandle) -> Option<AnyModelHandle> {
570        self.app.upgrade_any_model_handle(handle)
571    }
572}
573
574impl<'a> UpgradeViewHandle for LayoutContext<'a> {
575    fn upgrade_view_handle<T: View>(&self, handle: &WeakViewHandle<T>) -> Option<ViewHandle<T>> {
576        self.app.upgrade_view_handle(handle)
577    }
578
579    fn upgrade_any_view_handle(&self, handle: &crate::AnyWeakViewHandle) -> Option<AnyViewHandle> {
580        self.app.upgrade_any_view_handle(handle)
581    }
582}
583
584pub struct PaintContext<'a> {
585    rendered_views: &'a mut HashMap<usize, ElementBox>,
586    view_stack: Vec<usize>,
587    pub window_size: Vector2F,
588    pub scene: &'a mut Scene,
589    pub font_cache: &'a FontCache,
590    pub text_layout_cache: &'a TextLayoutCache,
591    pub app: &'a AppContext,
592}
593
594impl<'a> PaintContext<'a> {
595    fn paint(&mut self, view_id: usize, origin: Vector2F, visible_bounds: RectF) {
596        if let Some(mut tree) = self.rendered_views.remove(&view_id) {
597            self.view_stack.push(view_id);
598            tree.paint(origin, visible_bounds, self);
599            self.rendered_views.insert(view_id, tree);
600            self.view_stack.pop();
601        }
602    }
603
604    #[inline]
605    pub fn paint_layer<F>(&mut self, clip_bounds: Option<RectF>, f: F)
606    where
607        F: FnOnce(&mut Self) -> (),
608    {
609        self.scene.push_layer(clip_bounds);
610        f(self);
611        self.scene.pop_layer();
612    }
613
614    pub fn current_view_id(&self) -> usize {
615        *self.view_stack.last().unwrap()
616    }
617}
618
619impl<'a> Deref for PaintContext<'a> {
620    type Target = AppContext;
621
622    fn deref(&self) -> &Self::Target {
623        self.app
624    }
625}
626
627pub struct EventContext<'a> {
628    rendered_views: &'a mut HashMap<usize, ElementBox>,
629    dispatched_actions: Vec<DispatchDirective>,
630    pub font_cache: &'a FontCache,
631    pub text_layout_cache: &'a TextLayoutCache,
632    pub app: &'a mut MutableAppContext,
633    pub window_id: usize,
634    pub notify_count: usize,
635    view_stack: Vec<usize>,
636    invalidated_views: HashSet<usize>,
637}
638
639impl<'a> EventContext<'a> {
640    fn dispatch_event(&mut self, view_id: usize, event: &Event) -> bool {
641        if let Some(mut element) = self.rendered_views.remove(&view_id) {
642            let result =
643                self.with_current_view(view_id, |this| element.dispatch_event(event, this));
644            self.rendered_views.insert(view_id, element);
645            result
646        } else {
647            false
648        }
649    }
650
651    fn with_current_view<F, T>(&mut self, view_id: usize, f: F) -> T
652    where
653        F: FnOnce(&mut Self) -> T,
654    {
655        self.view_stack.push(view_id);
656        let result = f(self);
657        self.view_stack.pop();
658        result
659    }
660
661    pub fn window_id(&self) -> usize {
662        self.window_id
663    }
664
665    pub fn view_id(&self) -> Option<usize> {
666        self.view_stack.last().copied()
667    }
668
669    pub fn is_parent_view_focused(&self) -> bool {
670        if let Some(parent_view_id) = self.view_stack.last() {
671            self.app.focused_view_id(self.window_id) == Some(*parent_view_id)
672        } else {
673            false
674        }
675    }
676
677    pub fn focus_parent_view(&mut self) {
678        if let Some(parent_view_id) = self.view_stack.last() {
679            self.app.focus(self.window_id, Some(*parent_view_id))
680        }
681    }
682
683    pub fn dispatch_any_action(&mut self, action: Box<dyn Action>) {
684        self.dispatched_actions.push(DispatchDirective {
685            dispatcher_view_id: self.view_stack.last().copied(),
686            action,
687        });
688    }
689
690    pub fn dispatch_action<A: Action>(&mut self, action: A) {
691        self.dispatch_any_action(Box::new(action));
692    }
693
694    pub fn notify(&mut self) {
695        self.notify_count += 1;
696        if let Some(view_id) = self.view_stack.last() {
697            self.invalidated_views.insert(*view_id);
698        }
699    }
700
701    pub fn notify_count(&self) -> usize {
702        self.notify_count
703    }
704}
705
706impl<'a> Deref for EventContext<'a> {
707    type Target = MutableAppContext;
708
709    fn deref(&self) -> &Self::Target {
710        self.app
711    }
712}
713
714impl<'a> DerefMut for EventContext<'a> {
715    fn deref_mut(&mut self) -> &mut Self::Target {
716        self.app
717    }
718}
719
720pub struct DebugContext<'a> {
721    rendered_views: &'a HashMap<usize, ElementBox>,
722    pub font_cache: &'a FontCache,
723    pub app: &'a AppContext,
724}
725
726#[derive(Clone, Copy, Debug, Eq, PartialEq)]
727pub enum Axis {
728    Horizontal,
729    Vertical,
730}
731
732impl Axis {
733    pub fn invert(self) -> Self {
734        match self {
735            Self::Horizontal => Self::Vertical,
736            Self::Vertical => Self::Horizontal,
737        }
738    }
739}
740
741impl ToJson for Axis {
742    fn to_json(&self) -> serde_json::Value {
743        match self {
744            Axis::Horizontal => json!("horizontal"),
745            Axis::Vertical => json!("vertical"),
746        }
747    }
748}
749
750pub trait Vector2FExt {
751    fn along(self, axis: Axis) -> f32;
752}
753
754impl Vector2FExt for Vector2F {
755    fn along(self, axis: Axis) -> f32 {
756        match axis {
757            Axis::Horizontal => self.x(),
758            Axis::Vertical => self.y(),
759        }
760    }
761}
762
763#[derive(Copy, Clone, Debug)]
764pub struct SizeConstraint {
765    pub min: Vector2F,
766    pub max: Vector2F,
767}
768
769impl SizeConstraint {
770    pub fn new(min: Vector2F, max: Vector2F) -> Self {
771        Self { min, max }
772    }
773
774    pub fn strict(size: Vector2F) -> Self {
775        Self {
776            min: size,
777            max: size,
778        }
779    }
780
781    pub fn strict_along(axis: Axis, max: f32) -> Self {
782        match axis {
783            Axis::Horizontal => Self {
784                min: vec2f(max, 0.0),
785                max: vec2f(max, f32::INFINITY),
786            },
787            Axis::Vertical => Self {
788                min: vec2f(0.0, max),
789                max: vec2f(f32::INFINITY, max),
790            },
791        }
792    }
793
794    pub fn max_along(&self, axis: Axis) -> f32 {
795        match axis {
796            Axis::Horizontal => self.max.x(),
797            Axis::Vertical => self.max.y(),
798        }
799    }
800
801    pub fn min_along(&self, axis: Axis) -> f32 {
802        match axis {
803            Axis::Horizontal => self.min.x(),
804            Axis::Vertical => self.min.y(),
805        }
806    }
807
808    pub fn constrain(&self, size: Vector2F) -> Vector2F {
809        vec2f(
810            size.x().min(self.max.x()).max(self.min.x()),
811            size.y().min(self.max.y()).max(self.min.y()),
812        )
813    }
814}
815
816impl Default for SizeConstraint {
817    fn default() -> Self {
818        SizeConstraint {
819            min: Vector2F::zero(),
820            max: Vector2F::splat(f32::INFINITY),
821        }
822    }
823}
824
825impl ToJson for SizeConstraint {
826    fn to_json(&self) -> serde_json::Value {
827        json!({
828            "min": self.min.to_json(),
829            "max": self.max.to_json(),
830        })
831    }
832}
833
834pub struct ChildView {
835    view: AnyViewHandle,
836}
837
838impl ChildView {
839    pub fn new(view: impl Into<AnyViewHandle>) -> Self {
840        Self { view: view.into() }
841    }
842}
843
844impl Element for ChildView {
845    type LayoutState = ();
846    type PaintState = ();
847
848    fn layout(
849        &mut self,
850        constraint: SizeConstraint,
851        cx: &mut LayoutContext,
852    ) -> (Vector2F, Self::LayoutState) {
853        let size = cx.layout(self.view.id(), constraint);
854        (size, ())
855    }
856
857    fn paint(
858        &mut self,
859        bounds: RectF,
860        visible_bounds: RectF,
861        _: &mut Self::LayoutState,
862        cx: &mut PaintContext,
863    ) -> Self::PaintState {
864        cx.paint(self.view.id(), bounds.origin(), visible_bounds);
865    }
866
867    fn dispatch_event(
868        &mut self,
869        event: &Event,
870        _: RectF,
871        _: RectF,
872        _: &mut Self::LayoutState,
873        _: &mut Self::PaintState,
874        cx: &mut EventContext,
875    ) -> bool {
876        cx.dispatch_event(self.view.id(), event)
877    }
878
879    fn debug(
880        &self,
881        bounds: RectF,
882        _: &Self::LayoutState,
883        _: &Self::PaintState,
884        cx: &DebugContext,
885    ) -> serde_json::Value {
886        json!({
887            "type": "ChildView",
888            "view_id": self.view.id(),
889            "bounds": bounds.to_json(),
890            "view": self.view.debug_json(cx.app),
891            "child": if let Some(view) = cx.rendered_views.get(&self.view.id()) {
892                view.debug(cx)
893            } else {
894                json!(null)
895            }
896        })
897    }
898}