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    ParentId, ReadModel, ReadView, RenderContext, RenderParams, Scene, UpgradeModelHandle,
 14    UpgradeViewHandle, View, ViewHandle, WeakModelHandle, WeakViewHandle,
 15};
 16use collections::{HashMap, HashSet};
 17use pathfinder_geometry::vector::{vec2f, Vector2F};
 18use serde_json::json;
 19use smallvec::SmallVec;
 20use std::{
 21    marker::PhantomData,
 22    ops::{Deref, DerefMut, Range},
 23    sync::Arc,
 24};
 25
 26pub struct Presenter {
 27    window_id: usize,
 28    pub(crate) rendered_views: HashMap<usize, ElementBox>,
 29    cursor_regions: Vec<CursorRegion>,
 30    mouse_regions: Vec<(MouseRegion, usize)>,
 31    font_cache: Arc<FontCache>,
 32    text_layout_cache: TextLayoutCache,
 33    asset_cache: Arc<AssetCache>,
 34    last_mouse_moved_event: Option<MouseMovedEvent>,
 35    hovered_region_ids: HashSet<MouseRegionId>,
 36    clicked_region: Option<MouseRegion>,
 37    right_clicked_region: Option<MouseRegion>,
 38    prev_drag_position: Option<Vector2F>,
 39    titlebar_height: f32,
 40}
 41
 42impl Presenter {
 43    pub fn new(
 44        window_id: usize,
 45        titlebar_height: f32,
 46        font_cache: Arc<FontCache>,
 47        text_layout_cache: TextLayoutCache,
 48        asset_cache: Arc<AssetCache>,
 49        cx: &mut MutableAppContext,
 50    ) -> Self {
 51        Self {
 52            window_id,
 53            rendered_views: cx.render_views(window_id, titlebar_height),
 54            cursor_regions: Default::default(),
 55            mouse_regions: Default::default(),
 56            font_cache,
 57            text_layout_cache,
 58            asset_cache,
 59            last_mouse_moved_event: None,
 60            hovered_region_ids: Default::default(),
 61            clicked_region: None,
 62            right_clicked_region: None,
 63            prev_drag_position: None,
 64            titlebar_height,
 65        }
 66    }
 67
 68    // pub fn dispatch_path(&self, app: &AppContext) -> Vec<usize> {
 69    //     let mut path = Vec::new();
 70    //     if let Some(view_id) = app.focused_view_id(self.window_id) {
 71    //         self.compute_dispatch_path_from(view_id, &mut path)
 72    //     }
 73    //     path
 74    // }
 75
 76    // pub(crate) fn compute_dispatch_path_from(&self, mut view_id: usize, path: &mut Vec<usize>) {
 77    //     path.push(view_id);
 78    //     while let Some(parent_id) = self.parents.get(&view_id).copied() {
 79    //         path.push(parent_id);
 80    //         view_id = parent_id;
 81    //     }
 82    //     path.reverse();
 83    // }
 84
 85    pub fn invalidate(
 86        &mut self,
 87        invalidation: &mut WindowInvalidation,
 88        cx: &mut MutableAppContext,
 89    ) {
 90        cx.start_frame();
 91        for view_id in &invalidation.removed {
 92            invalidation.updated.remove(view_id);
 93            self.rendered_views.remove(view_id);
 94        }
 95        for view_id in &invalidation.updated {
 96            self.rendered_views.insert(
 97                *view_id,
 98                cx.render_view(RenderParams {
 99                    window_id: self.window_id,
100                    view_id: *view_id,
101                    titlebar_height: self.titlebar_height,
102                    hovered_region_ids: self.hovered_region_ids.clone(),
103                    clicked_region_id: self.clicked_region.as_ref().and_then(MouseRegion::id),
104                    right_clicked_region_id: self
105                        .right_clicked_region
106                        .as_ref()
107                        .and_then(MouseRegion::id),
108                    refreshing: false,
109                })
110                .unwrap(),
111            );
112        }
113    }
114
115    pub fn refresh(&mut self, invalidation: &mut WindowInvalidation, cx: &mut MutableAppContext) {
116        self.invalidate(invalidation, cx);
117        for (view_id, view) in &mut self.rendered_views {
118            if !invalidation.updated.contains(view_id) {
119                *view = cx
120                    .render_view(RenderParams {
121                        window_id: self.window_id,
122                        view_id: *view_id,
123                        titlebar_height: self.titlebar_height,
124                        hovered_region_ids: self.hovered_region_ids.clone(),
125                        clicked_region_id: self.clicked_region.as_ref().and_then(MouseRegion::id),
126                        right_clicked_region_id: self
127                            .right_clicked_region
128                            .as_ref()
129                            .and_then(MouseRegion::id),
130                        refreshing: true,
131                    })
132                    .unwrap();
133            }
134        }
135    }
136
137    pub fn build_scene(
138        &mut self,
139        window_size: Vector2F,
140        scale_factor: f32,
141        refreshing: bool,
142        cx: &mut MutableAppContext,
143    ) -> Scene {
144        let mut scene = Scene::new(scale_factor);
145
146        if let Some(root_view_id) = cx.root_view_id(self.window_id) {
147            self.layout(window_size, refreshing, cx);
148            let mut paint_cx = self.build_paint_context(&mut scene, window_size, cx);
149            paint_cx.paint(
150                root_view_id,
151                Vector2F::zero(),
152                RectF::new(Vector2F::zero(), window_size),
153            );
154            self.text_layout_cache.finish_frame();
155            self.cursor_regions = scene.cursor_regions();
156            self.mouse_regions = scene.mouse_regions();
157
158            if cx.window_is_active(self.window_id) {
159                if let Some(event) = self.last_mouse_moved_event.clone() {
160                    let mut invalidated_views = Vec::new();
161                    self.handle_hover_events(&event, &mut invalidated_views, cx);
162
163                    for view_id in invalidated_views {
164                        cx.notify_view(self.window_id, view_id);
165                    }
166                }
167            }
168        } else {
169            log::error!("could not find root_view_id for window {}", self.window_id);
170        }
171
172        scene
173    }
174
175    fn layout(&mut self, window_size: Vector2F, refreshing: bool, cx: &mut MutableAppContext) {
176        if let Some(root_view_id) = cx.root_view_id(self.window_id) {
177            self.build_layout_context(window_size, refreshing, cx)
178                .layout(root_view_id, SizeConstraint::strict(window_size));
179        }
180    }
181
182    pub fn build_layout_context<'a>(
183        &'a mut self,
184        window_size: Vector2F,
185        refreshing: bool,
186        cx: &'a mut MutableAppContext,
187    ) -> LayoutContext<'a> {
188        LayoutContext {
189            window_id: self.window_id,
190            rendered_views: &mut self.rendered_views,
191            font_cache: &self.font_cache,
192            font_system: cx.platform().fonts(),
193            text_layout_cache: &self.text_layout_cache,
194            asset_cache: &self.asset_cache,
195            view_stack: Vec::new(),
196            refreshing,
197            hovered_region_ids: self.hovered_region_ids.clone(),
198            clicked_region_id: self.clicked_region.as_ref().and_then(MouseRegion::id),
199            right_clicked_region_id: self.right_clicked_region.as_ref().and_then(MouseRegion::id),
200            titlebar_height: self.titlebar_height,
201            window_size,
202            app: cx,
203        }
204    }
205
206    pub fn build_paint_context<'a>(
207        &'a mut self,
208        scene: &'a mut Scene,
209        window_size: Vector2F,
210        cx: &'a mut MutableAppContext,
211    ) -> PaintContext {
212        PaintContext {
213            scene,
214            window_size,
215            font_cache: &self.font_cache,
216            text_layout_cache: &self.text_layout_cache,
217            rendered_views: &mut self.rendered_views,
218            view_stack: Vec::new(),
219            app: cx,
220        }
221    }
222
223    pub fn rect_for_text_range(&self, range_utf16: Range<usize>, cx: &AppContext) -> Option<RectF> {
224        cx.focused_view_id(self.window_id).and_then(|view_id| {
225            let cx = MeasurementContext {
226                app: cx,
227                rendered_views: &self.rendered_views,
228                window_id: self.window_id,
229            };
230            cx.rect_for_text_range(view_id, range_utf16)
231        })
232    }
233
234    pub fn dispatch_event(&mut self, event: Event, cx: &mut MutableAppContext) -> bool {
235        if let Some(root_view_id) = cx.root_view_id(self.window_id) {
236            let mut invalidated_views = Vec::new();
237            let mut mouse_down_out_handlers = Vec::new();
238            let mut mouse_moved_region = None;
239            let mut mouse_down_region = None;
240            let mut clicked_region = None;
241            let mut dragged_region = None;
242
243            match &event {
244                Event::MouseDown(
245                    e @ MouseButtonEvent {
246                        position, button, ..
247                    },
248                ) => {
249                    let mut hit = false;
250                    for (region, _) in self.mouse_regions.iter().rev() {
251                        if region.bounds.contains_point(*position) {
252                            if !hit {
253                                hit = true;
254                                invalidated_views.push(region.view_id);
255                                mouse_down_region =
256                                    Some((region.clone(), MouseRegionEvent::Down(e.clone())));
257                                self.clicked_region = Some(region.clone());
258                                self.prev_drag_position = Some(*position);
259                            }
260                        } else if let Some(handler) = region
261                            .handlers
262                            .get(&(MouseRegionEvent::down_out_disc(), Some(*button)))
263                        {
264                            mouse_down_out_handlers.push((
265                                handler,
266                                region.view_id,
267                                MouseRegionEvent::DownOut(e.clone()),
268                            ));
269                        }
270                    }
271                }
272
273                &Event::MouseUp(
274                    e @ MouseButtonEvent {
275                        position, button, ..
276                    },
277                ) => {
278                    self.prev_drag_position.take();
279                    if let Some(region) = self.clicked_region.take() {
280                        invalidated_views.push(region.view_id);
281                        if region.bounds.contains_point(position) {
282                            clicked_region = Some((region, MouseRegionEvent::Click(e.clone())));
283                        }
284                    }
285
286                    if let Some(moved) = &mut self.last_mouse_moved_event {
287                        if moved.pressed_button == Some(button) {
288                            moved.pressed_button = None;
289                        }
290                    }
291                }
292
293                Event::MouseMoved(e @ MouseMovedEvent { position, .. }) => {
294                    if let Some((clicked_region, prev_drag_position)) = self
295                        .clicked_region
296                        .as_ref()
297                        .zip(self.prev_drag_position.as_mut())
298                    {
299                        dragged_region = Some((
300                            clicked_region.clone(),
301                            MouseRegionEvent::Drag(*prev_drag_position, *e),
302                        ));
303                        *prev_drag_position = *position;
304                    }
305
306                    for (region, _) in self.mouse_regions.iter().rev() {
307                        if region.bounds.contains_point(*position) {
308                            invalidated_views.push(region.view_id);
309                            mouse_moved_region =
310                                Some((region.clone(), MouseRegionEvent::Move(e.clone())));
311                            break;
312                        }
313                    }
314
315                    self.last_mouse_moved_event = Some(e.clone());
316                }
317
318                _ => {}
319            }
320
321            let (mut handled, mut event_cx) = if let Event::MouseMoved(e) = &event {
322                self.handle_hover_events(e, &mut invalidated_views, cx)
323            } else {
324                (false, self.build_event_context(cx))
325            };
326
327            for (handler, view_id, region_event) in mouse_down_out_handlers {
328                event_cx.with_current_view(view_id, |event_cx| handler(region_event, event_cx))
329            }
330
331            if let Some((mouse_down_region, region_event)) = mouse_down_region {
332                handled = true;
333                if let Some(mouse_down_callback) =
334                    mouse_down_region.handlers.get(&region_event.handler_key())
335                {
336                    event_cx.with_current_view(mouse_down_region.view_id, |event_cx| {
337                        mouse_down_callback(region_event, event_cx);
338                    })
339                }
340            }
341
342            if let Some((move_moved_region, region_event)) = mouse_moved_region {
343                handled = true;
344                if let Some(mouse_moved_callback) =
345                    move_moved_region.handlers.get(&region_event.handler_key())
346                {
347                    event_cx.with_current_view(move_moved_region.view_id, |event_cx| {
348                        mouse_moved_callback(region_event, event_cx);
349                    })
350                }
351            }
352
353            if let Some((clicked_region, region_event)) = clicked_region {
354                handled = true;
355                if let Some(click_callback) =
356                    clicked_region.handlers.get(&region_event.handler_key())
357                {
358                    event_cx.with_current_view(clicked_region.view_id, |event_cx| {
359                        click_callback(region_event, event_cx);
360                    })
361                }
362            }
363
364            if let Some((dragged_region, region_event)) = dragged_region {
365                handled = true;
366                if let Some(drag_callback) =
367                    dragged_region.handlers.get(&region_event.handler_key())
368                {
369                    event_cx.with_current_view(dragged_region.view_id, |event_cx| {
370                        drag_callback(region_event, event_cx);
371                    })
372                }
373            }
374
375            if !handled {
376                handled = event_cx.dispatch_event(root_view_id, &event);
377            }
378
379            invalidated_views.extend(event_cx.invalidated_views);
380
381            for view_id in invalidated_views {
382                cx.notify_view(self.window_id, view_id);
383            }
384
385            handled
386        } else {
387            false
388        }
389    }
390
391    fn handle_hover_events<'a>(
392        &'a mut self,
393        e @ MouseMovedEvent {
394            position,
395            pressed_button,
396            ..
397        }: &MouseMovedEvent,
398        invalidated_views: &mut Vec<usize>,
399        cx: &'a mut MutableAppContext,
400    ) -> (bool, EventContext<'a>) {
401        let mut hover_regions = Vec::new();
402
403        if pressed_button.is_none() {
404            let mut style_to_assign = CursorStyle::Arrow;
405            for region in self.cursor_regions.iter().rev() {
406                if region.bounds.contains_point(*position) {
407                    style_to_assign = region.style;
408                    break;
409                }
410            }
411            cx.platform().set_cursor_style(style_to_assign);
412
413            let mut hover_depth = None;
414            for (region, depth) in self.mouse_regions.iter().rev() {
415                if region.bounds.contains_point(*position)
416                    && hover_depth.map_or(true, |hover_depth| hover_depth == *depth)
417                {
418                    hover_depth = Some(*depth);
419                    if let Some(region_id) = region.id() {
420                        if !self.hovered_region_ids.contains(&region_id) {
421                            invalidated_views.push(region.view_id);
422                            hover_regions.push((region.clone(), MouseRegionEvent::Hover(true, *e)));
423                            self.hovered_region_ids.insert(region_id);
424                        }
425                    }
426                } else if let Some(region_id) = region.id() {
427                    if self.hovered_region_ids.contains(&region_id) {
428                        invalidated_views.push(region.view_id);
429                        hover_regions.push((region.clone(), MouseRegionEvent::Hover(false, *e)));
430                        self.hovered_region_ids.remove(&region_id);
431                    }
432                }
433            }
434        }
435
436        let mut event_cx = self.build_event_context(cx);
437        let mut handled = false;
438
439        for (hover_region, region_event) in hover_regions {
440            handled = true;
441            if let Some(hover_callback) = hover_region.handlers.get(&region_event.handler_key()) {
442                event_cx.with_current_view(hover_region.view_id, |event_cx| {
443                    hover_callback(region_event, event_cx);
444                })
445            }
446        }
447
448        (handled, event_cx)
449    }
450
451    pub fn build_event_context<'a>(
452        &'a mut self,
453        cx: &'a mut MutableAppContext,
454    ) -> EventContext<'a> {
455        EventContext {
456            rendered_views: &mut self.rendered_views,
457            font_cache: &self.font_cache,
458            text_layout_cache: &self.text_layout_cache,
459            view_stack: Default::default(),
460            invalidated_views: Default::default(),
461            notify_count: 0,
462            window_id: self.window_id,
463            app: cx,
464        }
465    }
466
467    pub fn debug_elements(&self, cx: &AppContext) -> Option<json::Value> {
468        let view = cx.root_view(self.window_id)?;
469        Some(json!({
470            "root_view": view.debug_json(cx),
471            "root_element": self.rendered_views.get(&view.id())
472                .map(|root_element| {
473                    root_element.debug(&DebugContext {
474                        rendered_views: &self.rendered_views,
475                        font_cache: &self.font_cache,
476                        app: cx,
477                    })
478                })
479        }))
480    }
481}
482
483pub struct LayoutContext<'a> {
484    window_id: usize,
485    rendered_views: &'a mut HashMap<usize, ElementBox>,
486    view_stack: Vec<usize>,
487    pub font_cache: &'a Arc<FontCache>,
488    pub font_system: Arc<dyn FontSystem>,
489    pub text_layout_cache: &'a TextLayoutCache,
490    pub asset_cache: &'a AssetCache,
491    pub app: &'a mut MutableAppContext,
492    pub refreshing: bool,
493    pub window_size: Vector2F,
494    titlebar_height: f32,
495    hovered_region_ids: HashSet<MouseRegionId>,
496    clicked_region_id: Option<MouseRegionId>,
497    right_clicked_region_id: Option<MouseRegionId>,
498}
499
500impl<'a> LayoutContext<'a> {
501    pub(crate) fn keystrokes_for_action(
502        &self,
503        action: &dyn Action,
504    ) -> Option<SmallVec<[Keystroke; 2]>> {
505        self.app
506            .keystrokes_for_action(self.window_id, &self.view_stack, action)
507    }
508
509    fn layout(&mut self, view_id: usize, constraint: SizeConstraint) -> Vector2F {
510        let print_error = |view_id| {
511            format!(
512                "{} with id {}",
513                self.app.name_for_view(self.window_id, view_id).unwrap(),
514                view_id,
515            )
516        };
517        match (
518            self.view_stack.last(),
519            self.app.parents.get(&(self.window_id, view_id)),
520        ) {
521            (Some(layout_parent), Some(ParentId::View(app_parent))) => {
522                if layout_parent != app_parent {
523                    panic!(
524                        "View {} was laid out with parent {} when it was constructed with parent {}", 
525                        print_error(view_id),
526                        print_error(*layout_parent),
527                        print_error(*app_parent))
528                }
529            }
530            (None, Some(ParentId::View(app_parent))) => panic!(
531                "View {} was laid out without a parent when it was constructed with parent {}",
532                print_error(view_id),
533                print_error(*app_parent)
534            ),
535            (Some(layout_parent), Some(ParentId::Root)) => panic!(
536                "View {} was laid out with parent {} when it was constructed as a window root",
537                print_error(view_id),
538                print_error(*layout_parent),
539            ),
540            (_, None) => panic!(
541                "View {} did not have a registered parent in the app context",
542                print_error(view_id),
543            ),
544            _ => {}
545        }
546
547        self.view_stack.push(view_id);
548        let mut rendered_view = self.rendered_views.remove(&view_id).unwrap();
549        let size = rendered_view.layout(constraint, self);
550        self.rendered_views.insert(view_id, rendered_view);
551        self.view_stack.pop();
552        size
553    }
554
555    pub fn render<F, V, T>(&mut self, handle: &ViewHandle<V>, f: F) -> T
556    where
557        F: FnOnce(&mut V, &mut RenderContext<V>) -> T,
558        V: View,
559    {
560        handle.update(self.app, |view, cx| {
561            let mut render_cx = RenderContext {
562                app: cx,
563                window_id: handle.window_id(),
564                view_id: handle.id(),
565                view_type: PhantomData,
566                titlebar_height: self.titlebar_height,
567                hovered_region_ids: self.hovered_region_ids.clone(),
568                clicked_region_id: self.clicked_region_id,
569                right_clicked_region_id: self.right_clicked_region_id,
570                refreshing: self.refreshing,
571            };
572            f(view, &mut render_cx)
573        })
574    }
575}
576
577impl<'a> Deref for LayoutContext<'a> {
578    type Target = MutableAppContext;
579
580    fn deref(&self) -> &Self::Target {
581        self.app
582    }
583}
584
585impl<'a> DerefMut for LayoutContext<'a> {
586    fn deref_mut(&mut self) -> &mut Self::Target {
587        self.app
588    }
589}
590
591impl<'a> ReadView for LayoutContext<'a> {
592    fn read_view<T: View>(&self, handle: &ViewHandle<T>) -> &T {
593        self.app.read_view(handle)
594    }
595}
596
597impl<'a> ReadModel for LayoutContext<'a> {
598    fn read_model<T: Entity>(&self, handle: &ModelHandle<T>) -> &T {
599        self.app.read_model(handle)
600    }
601}
602
603impl<'a> UpgradeModelHandle for LayoutContext<'a> {
604    fn upgrade_model_handle<T: Entity>(
605        &self,
606        handle: &WeakModelHandle<T>,
607    ) -> Option<ModelHandle<T>> {
608        self.app.upgrade_model_handle(handle)
609    }
610
611    fn model_handle_is_upgradable<T: Entity>(&self, handle: &WeakModelHandle<T>) -> bool {
612        self.app.model_handle_is_upgradable(handle)
613    }
614
615    fn upgrade_any_model_handle(&self, handle: &AnyWeakModelHandle) -> Option<AnyModelHandle> {
616        self.app.upgrade_any_model_handle(handle)
617    }
618}
619
620impl<'a> UpgradeViewHandle for LayoutContext<'a> {
621    fn upgrade_view_handle<T: View>(&self, handle: &WeakViewHandle<T>) -> Option<ViewHandle<T>> {
622        self.app.upgrade_view_handle(handle)
623    }
624
625    fn upgrade_any_view_handle(&self, handle: &crate::AnyWeakViewHandle) -> Option<AnyViewHandle> {
626        self.app.upgrade_any_view_handle(handle)
627    }
628}
629
630pub struct PaintContext<'a> {
631    rendered_views: &'a mut HashMap<usize, ElementBox>,
632    view_stack: Vec<usize>,
633    pub window_size: Vector2F,
634    pub scene: &'a mut Scene,
635    pub font_cache: &'a FontCache,
636    pub text_layout_cache: &'a TextLayoutCache,
637    pub app: &'a AppContext,
638}
639
640impl<'a> PaintContext<'a> {
641    fn paint(&mut self, view_id: usize, origin: Vector2F, visible_bounds: RectF) {
642        if let Some(mut tree) = self.rendered_views.remove(&view_id) {
643            self.view_stack.push(view_id);
644            tree.paint(origin, visible_bounds, self);
645            self.rendered_views.insert(view_id, tree);
646            self.view_stack.pop();
647        }
648    }
649
650    #[inline]
651    pub fn paint_layer<F>(&mut self, clip_bounds: Option<RectF>, f: F)
652    where
653        F: FnOnce(&mut Self),
654    {
655        self.scene.push_layer(clip_bounds);
656        f(self);
657        self.scene.pop_layer();
658    }
659
660    pub fn current_view_id(&self) -> usize {
661        *self.view_stack.last().unwrap()
662    }
663}
664
665impl<'a> Deref for PaintContext<'a> {
666    type Target = AppContext;
667
668    fn deref(&self) -> &Self::Target {
669        self.app
670    }
671}
672
673pub struct EventContext<'a> {
674    rendered_views: &'a mut HashMap<usize, ElementBox>,
675    pub font_cache: &'a FontCache,
676    pub text_layout_cache: &'a TextLayoutCache,
677    pub app: &'a mut MutableAppContext,
678    pub window_id: usize,
679    pub notify_count: usize,
680    view_stack: Vec<usize>,
681    invalidated_views: HashSet<usize>,
682}
683
684impl<'a> EventContext<'a> {
685    fn dispatch_event(&mut self, view_id: usize, event: &Event) -> bool {
686        if let Some(mut element) = self.rendered_views.remove(&view_id) {
687            let result =
688                self.with_current_view(view_id, |this| element.dispatch_event(event, this));
689            self.rendered_views.insert(view_id, element);
690            result
691        } else {
692            false
693        }
694    }
695
696    fn with_current_view<F, T>(&mut self, view_id: usize, f: F) -> T
697    where
698        F: FnOnce(&mut Self) -> T,
699    {
700        self.view_stack.push(view_id);
701        let result = f(self);
702        self.view_stack.pop();
703        result
704    }
705
706    pub fn window_id(&self) -> usize {
707        self.window_id
708    }
709
710    pub fn view_id(&self) -> Option<usize> {
711        self.view_stack.last().copied()
712    }
713
714    pub fn is_parent_view_focused(&self) -> bool {
715        if let Some(parent_view_id) = self.view_stack.last() {
716            self.app.focused_view_id(self.window_id) == Some(*parent_view_id)
717        } else {
718            false
719        }
720    }
721
722    pub fn focus_parent_view(&mut self) {
723        if let Some(parent_view_id) = self.view_stack.last() {
724            self.app.focus(self.window_id, Some(*parent_view_id))
725        }
726    }
727
728    pub fn dispatch_any_action(&mut self, action: Box<dyn Action>) {
729        self.app
730            .dispatch_any_action_at(self.window_id, *self.view_stack.last().unwrap(), action)
731    }
732
733    pub fn dispatch_action<A: Action>(&mut self, action: A) {
734        self.dispatch_any_action(Box::new(action));
735    }
736
737    pub fn notify(&mut self) {
738        self.notify_count += 1;
739        if let Some(view_id) = self.view_stack.last() {
740            self.invalidated_views.insert(*view_id);
741        }
742    }
743
744    pub fn notify_count(&self) -> usize {
745        self.notify_count
746    }
747}
748
749impl<'a> Deref for EventContext<'a> {
750    type Target = MutableAppContext;
751
752    fn deref(&self) -> &Self::Target {
753        self.app
754    }
755}
756
757impl<'a> DerefMut for EventContext<'a> {
758    fn deref_mut(&mut self) -> &mut Self::Target {
759        self.app
760    }
761}
762
763pub struct MeasurementContext<'a> {
764    app: &'a AppContext,
765    rendered_views: &'a HashMap<usize, ElementBox>,
766    pub window_id: usize,
767}
768
769impl<'a> Deref for MeasurementContext<'a> {
770    type Target = AppContext;
771
772    fn deref(&self) -> &Self::Target {
773        self.app
774    }
775}
776
777impl<'a> MeasurementContext<'a> {
778    fn rect_for_text_range(&self, view_id: usize, range_utf16: Range<usize>) -> Option<RectF> {
779        let element = self.rendered_views.get(&view_id)?;
780        element.rect_for_text_range(range_utf16, self)
781    }
782}
783
784pub struct DebugContext<'a> {
785    rendered_views: &'a HashMap<usize, ElementBox>,
786    pub font_cache: &'a FontCache,
787    pub app: &'a AppContext,
788}
789
790#[derive(Clone, Copy, Debug, Eq, PartialEq)]
791pub enum Axis {
792    Horizontal,
793    Vertical,
794}
795
796impl Axis {
797    pub fn invert(self) -> Self {
798        match self {
799            Self::Horizontal => Self::Vertical,
800            Self::Vertical => Self::Horizontal,
801        }
802    }
803}
804
805impl ToJson for Axis {
806    fn to_json(&self) -> serde_json::Value {
807        match self {
808            Axis::Horizontal => json!("horizontal"),
809            Axis::Vertical => json!("vertical"),
810        }
811    }
812}
813
814pub trait Vector2FExt {
815    fn along(self, axis: Axis) -> f32;
816}
817
818impl Vector2FExt for Vector2F {
819    fn along(self, axis: Axis) -> f32 {
820        match axis {
821            Axis::Horizontal => self.x(),
822            Axis::Vertical => self.y(),
823        }
824    }
825}
826
827#[derive(Copy, Clone, Debug)]
828pub struct SizeConstraint {
829    pub min: Vector2F,
830    pub max: Vector2F,
831}
832
833impl SizeConstraint {
834    pub fn new(min: Vector2F, max: Vector2F) -> Self {
835        Self { min, max }
836    }
837
838    pub fn strict(size: Vector2F) -> Self {
839        Self {
840            min: size,
841            max: size,
842        }
843    }
844
845    pub fn strict_along(axis: Axis, max: f32) -> Self {
846        match axis {
847            Axis::Horizontal => Self {
848                min: vec2f(max, 0.0),
849                max: vec2f(max, f32::INFINITY),
850            },
851            Axis::Vertical => Self {
852                min: vec2f(0.0, max),
853                max: vec2f(f32::INFINITY, max),
854            },
855        }
856    }
857
858    pub fn max_along(&self, axis: Axis) -> f32 {
859        match axis {
860            Axis::Horizontal => self.max.x(),
861            Axis::Vertical => self.max.y(),
862        }
863    }
864
865    pub fn min_along(&self, axis: Axis) -> f32 {
866        match axis {
867            Axis::Horizontal => self.min.x(),
868            Axis::Vertical => self.min.y(),
869        }
870    }
871
872    pub fn constrain(&self, size: Vector2F) -> Vector2F {
873        vec2f(
874            size.x().min(self.max.x()).max(self.min.x()),
875            size.y().min(self.max.y()).max(self.min.y()),
876        )
877    }
878}
879
880impl Default for SizeConstraint {
881    fn default() -> Self {
882        SizeConstraint {
883            min: Vector2F::zero(),
884            max: Vector2F::splat(f32::INFINITY),
885        }
886    }
887}
888
889impl ToJson for SizeConstraint {
890    fn to_json(&self) -> serde_json::Value {
891        json!({
892            "min": self.min.to_json(),
893            "max": self.max.to_json(),
894        })
895    }
896}
897
898pub struct ChildView {
899    view: AnyViewHandle,
900}
901
902impl ChildView {
903    pub fn new(view: impl Into<AnyViewHandle>) -> Self {
904        Self { view: view.into() }
905    }
906}
907
908impl Element for ChildView {
909    type LayoutState = ();
910    type PaintState = ();
911
912    fn layout(
913        &mut self,
914        constraint: SizeConstraint,
915        cx: &mut LayoutContext,
916    ) -> (Vector2F, Self::LayoutState) {
917        let size = cx.layout(self.view.id(), constraint);
918        (size, ())
919    }
920
921    fn paint(
922        &mut self,
923        bounds: RectF,
924        visible_bounds: RectF,
925        _: &mut Self::LayoutState,
926        cx: &mut PaintContext,
927    ) -> Self::PaintState {
928        cx.paint(self.view.id(), bounds.origin(), visible_bounds);
929    }
930
931    fn dispatch_event(
932        &mut self,
933        event: &Event,
934        _: RectF,
935        _: RectF,
936        _: &mut Self::LayoutState,
937        _: &mut Self::PaintState,
938        cx: &mut EventContext,
939    ) -> bool {
940        cx.dispatch_event(self.view.id(), event)
941    }
942
943    fn rect_for_text_range(
944        &self,
945        range_utf16: Range<usize>,
946        _: RectF,
947        _: RectF,
948        _: &Self::LayoutState,
949        _: &Self::PaintState,
950        cx: &MeasurementContext,
951    ) -> Option<RectF> {
952        cx.rect_for_text_range(self.view.id(), range_utf16)
953    }
954
955    fn debug(
956        &self,
957        bounds: RectF,
958        _: &Self::LayoutState,
959        _: &Self::PaintState,
960        cx: &DebugContext,
961    ) -> serde_json::Value {
962        json!({
963            "type": "ChildView",
964            "view_id": self.view.id(),
965            "bounds": bounds.to_json(),
966            "view": self.view.debug_json(cx.app),
967            "child": if let Some(view) = cx.rendered_views.get(&self.view.id()) {
968                view.debug(cx)
969            } else {
970                json!(null)
971            }
972        })
973    }
974}