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, 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                    self.dispatch_event(event, cx)
164                }
165            }
166        } else {
167            log::error!("could not find root_view_id for window {}", self.window_id);
168        }
169
170        scene
171    }
172
173    fn layout(&mut self, window_size: Vector2F, refreshing: bool, cx: &mut MutableAppContext) {
174        if let Some(root_view_id) = cx.root_view_id(self.window_id) {
175            self.build_layout_context(window_size, refreshing, cx)
176                .layout(root_view_id, SizeConstraint::strict(window_size));
177        }
178    }
179
180    pub fn build_layout_context<'a>(
181        &'a mut self,
182        window_size: Vector2F,
183        refreshing: bool,
184        cx: &'a mut MutableAppContext,
185    ) -> LayoutContext<'a> {
186        LayoutContext {
187            window_id: self.window_id,
188            rendered_views: &mut self.rendered_views,
189            parents: &mut self.parents,
190            font_cache: &self.font_cache,
191            font_system: cx.platform().fonts(),
192            text_layout_cache: &self.text_layout_cache,
193            asset_cache: &self.asset_cache,
194            view_stack: Vec::new(),
195            refreshing,
196            hovered_region_ids: self.hovered_region_ids.clone(),
197            clicked_region_id: self.clicked_region.as_ref().and_then(MouseRegion::id),
198            right_clicked_region_id: self.right_clicked_region.as_ref().and_then(MouseRegion::id),
199            titlebar_height: self.titlebar_height,
200            window_size,
201            app: cx,
202        }
203    }
204
205    pub fn build_paint_context<'a>(
206        &'a mut self,
207        scene: &'a mut Scene,
208        cx: &'a mut MutableAppContext,
209    ) -> PaintContext {
210        PaintContext {
211            scene,
212            font_cache: &self.font_cache,
213            text_layout_cache: &self.text_layout_cache,
214            rendered_views: &mut self.rendered_views,
215            view_stack: Vec::new(),
216            app: cx,
217        }
218    }
219
220    pub fn dispatch_event(&mut self, event: Event, cx: &mut MutableAppContext) {
221        if let Some(root_view_id) = cx.root_view_id(self.window_id) {
222            let mut invalidated_views = Vec::new();
223            let mut hovered_regions = Vec::new();
224            let mut unhovered_regions = Vec::new();
225            let mut mouse_down_out_handlers = Vec::new();
226            let mut mouse_down_region = None;
227            let mut clicked_region = None;
228            let mut right_mouse_down_region = None;
229            let mut right_clicked_region = None;
230            let mut dragged_region = None;
231
232            match event {
233                Event::LeftMouseDown { position, .. } => {
234                    let mut hit = false;
235                    for (region, _) in self.mouse_regions.iter().rev() {
236                        if region.bounds.contains_point(position) {
237                            if !hit {
238                                hit = true;
239                                invalidated_views.push(region.view_id);
240                                mouse_down_region = Some((region.clone(), position));
241                                self.clicked_region = Some(region.clone());
242                                self.prev_drag_position = Some(position);
243                            }
244                        } else if let Some(handler) = region.mouse_down_out.clone() {
245                            mouse_down_out_handlers.push((handler, region.view_id, position));
246                        }
247                    }
248                }
249                Event::LeftMouseUp {
250                    position,
251                    click_count,
252                    ..
253                } => {
254                    self.prev_drag_position.take();
255                    if let Some(region) = self.clicked_region.take() {
256                        invalidated_views.push(region.view_id);
257                        if region.bounds.contains_point(position) {
258                            clicked_region = Some((region, position, click_count));
259                        }
260                    }
261                }
262                Event::RightMouseDown { position, .. } => {
263                    let mut hit = false;
264                    for (region, _) in self.mouse_regions.iter().rev() {
265                        if region.bounds.contains_point(position) {
266                            if !hit {
267                                hit = true;
268                                invalidated_views.push(region.view_id);
269                                right_mouse_down_region = Some((region.clone(), position));
270                                self.right_clicked_region = Some(region.clone());
271                            }
272                        } else if let Some(handler) = region.right_mouse_down_out.clone() {
273                            mouse_down_out_handlers.push((handler, region.view_id, position));
274                        }
275                    }
276                }
277                Event::RightMouseUp {
278                    position,
279                    click_count,
280                    ..
281                } => {
282                    if let Some(region) = self.right_clicked_region.take() {
283                        invalidated_views.push(region.view_id);
284                        if region.bounds.contains_point(position) {
285                            right_clicked_region = Some((region, position, click_count));
286                        }
287                    }
288                }
289                Event::MouseMoved {
290                    position,
291                    left_mouse_down,
292                } => {
293                    self.last_mouse_moved_event = Some(event.clone());
294
295                    if !left_mouse_down {
296                        let mut style_to_assign = CursorStyle::Arrow;
297                        for region in self.cursor_regions.iter().rev() {
298                            if region.bounds.contains_point(position) {
299                                style_to_assign = region.style;
300                                break;
301                            }
302                        }
303                        cx.platform().set_cursor_style(style_to_assign);
304
305                        let mut hover_depth = None;
306                        for (region, depth) in self.mouse_regions.iter().rev() {
307                            if region.bounds.contains_point(position)
308                                && hover_depth.map_or(true, |hover_depth| hover_depth == *depth)
309                            {
310                                hover_depth = Some(*depth);
311                                if let Some(region_id) = region.id() {
312                                    if !self.hovered_region_ids.contains(&region_id) {
313                                        invalidated_views.push(region.view_id);
314                                        hovered_regions.push(region.clone());
315                                        self.hovered_region_ids.insert(region_id);
316                                    }
317                                }
318                            } else {
319                                if let Some(region_id) = region.id() {
320                                    if self.hovered_region_ids.contains(&region_id) {
321                                        invalidated_views.push(region.view_id);
322                                        unhovered_regions.push(region.clone());
323                                        self.hovered_region_ids.remove(&region_id);
324                                    }
325                                }
326                            }
327                        }
328                    }
329                }
330                Event::LeftMouseDragged { position } => {
331                    if let Some((clicked_region, prev_drag_position)) = self
332                        .clicked_region
333                        .as_ref()
334                        .zip(self.prev_drag_position.as_mut())
335                    {
336                        dragged_region =
337                            Some((clicked_region.clone(), position - *prev_drag_position));
338                        *prev_drag_position = position;
339                    }
340
341                    self.last_mouse_moved_event = Some(Event::MouseMoved {
342                        position,
343                        left_mouse_down: true,
344                    });
345                }
346                _ => {}
347            }
348
349            let mut event_cx = self.build_event_context(cx);
350            let mut handled = false;
351            for unhovered_region in unhovered_regions {
352                if let Some(hover_callback) = unhovered_region.hover {
353                    handled = true;
354                    event_cx.with_current_view(unhovered_region.view_id, |event_cx| {
355                        hover_callback(false, event_cx);
356                    })
357                }
358            }
359
360            for hovered_region in hovered_regions {
361                if let Some(hover_callback) = hovered_region.hover {
362                    handled = true;
363                    event_cx.with_current_view(hovered_region.view_id, |event_cx| {
364                        hover_callback(true, event_cx);
365                    })
366                }
367            }
368
369            for (handler, view_id, position) in mouse_down_out_handlers {
370                event_cx.with_current_view(view_id, |event_cx| handler(position, event_cx))
371            }
372
373            if let Some((mouse_down_region, position)) = mouse_down_region {
374                if let Some(mouse_down_callback) = mouse_down_region.mouse_down {
375                    handled = true;
376                    event_cx.with_current_view(mouse_down_region.view_id, |event_cx| {
377                        mouse_down_callback(position, event_cx);
378                    })
379                }
380            }
381
382            if let Some((clicked_region, position, click_count)) = clicked_region {
383                if let Some(click_callback) = clicked_region.click {
384                    handled = true;
385                    event_cx.with_current_view(clicked_region.view_id, |event_cx| {
386                        click_callback(position, click_count, event_cx);
387                    })
388                }
389            }
390
391            if let Some((right_mouse_down_region, position)) = right_mouse_down_region {
392                if let Some(right_mouse_down_callback) = right_mouse_down_region.right_mouse_down {
393                    handled = true;
394                    event_cx.with_current_view(right_mouse_down_region.view_id, |event_cx| {
395                        right_mouse_down_callback(position, event_cx);
396                    })
397                }
398            }
399
400            if let Some((right_clicked_region, position, click_count)) = right_clicked_region {
401                if let Some(right_click_callback) = right_clicked_region.right_click {
402                    handled = true;
403                    event_cx.with_current_view(right_clicked_region.view_id, |event_cx| {
404                        right_click_callback(position, click_count, event_cx);
405                    })
406                }
407            }
408
409            if let Some((dragged_region, delta)) = dragged_region {
410                if let Some(drag_callback) = dragged_region.drag {
411                    handled = true;
412                    event_cx.with_current_view(dragged_region.view_id, |event_cx| {
413                        drag_callback(delta, event_cx);
414                    })
415                }
416            }
417
418            if !handled {
419                event_cx.dispatch_event(root_view_id, &event);
420            }
421
422            invalidated_views.extend(event_cx.invalidated_views);
423            let dispatch_directives = event_cx.dispatched_actions;
424
425            for view_id in invalidated_views {
426                cx.notify_view(self.window_id, view_id);
427            }
428
429            let mut dispatch_path = Vec::new();
430            for directive in dispatch_directives {
431                dispatch_path.clear();
432                if let Some(view_id) = directive.dispatcher_view_id {
433                    self.compute_dispatch_path_from(view_id, &mut dispatch_path);
434                }
435                cx.dispatch_action_any(self.window_id, &dispatch_path, directive.action.as_ref());
436            }
437        }
438    }
439
440    pub fn build_event_context<'a>(
441        &'a mut self,
442        cx: &'a mut MutableAppContext,
443    ) -> EventContext<'a> {
444        EventContext {
445            rendered_views: &mut self.rendered_views,
446            dispatched_actions: Default::default(),
447            font_cache: &self.font_cache,
448            text_layout_cache: &self.text_layout_cache,
449            view_stack: Default::default(),
450            invalidated_views: Default::default(),
451            notify_count: 0,
452            app: cx,
453        }
454    }
455
456    pub fn debug_elements(&self, cx: &AppContext) -> Option<json::Value> {
457        let view = cx.root_view(self.window_id)?;
458        Some(json!({
459            "root_view": view.debug_json(cx),
460            "root_element": self.rendered_views.get(&view.id())
461                .map(|root_element| {
462                    root_element.debug(&DebugContext {
463                        rendered_views: &self.rendered_views,
464                        font_cache: &self.font_cache,
465                        app: cx,
466                    })
467                })
468        }))
469    }
470}
471
472pub struct DispatchDirective {
473    pub dispatcher_view_id: Option<usize>,
474    pub action: Box<dyn Action>,
475}
476
477pub struct LayoutContext<'a> {
478    window_id: usize,
479    rendered_views: &'a mut HashMap<usize, ElementBox>,
480    parents: &'a mut HashMap<usize, usize>,
481    view_stack: Vec<usize>,
482    pub font_cache: &'a Arc<FontCache>,
483    pub font_system: Arc<dyn FontSystem>,
484    pub text_layout_cache: &'a TextLayoutCache,
485    pub asset_cache: &'a AssetCache,
486    pub app: &'a mut MutableAppContext,
487    pub refreshing: bool,
488    pub window_size: Vector2F,
489    titlebar_height: f32,
490    hovered_region_ids: HashSet<MouseRegionId>,
491    clicked_region_id: Option<MouseRegionId>,
492    right_clicked_region_id: Option<MouseRegionId>,
493}
494
495impl<'a> LayoutContext<'a> {
496    pub(crate) fn keystrokes_for_action(
497        &self,
498        action: &dyn Action,
499    ) -> Option<SmallVec<[Keystroke; 2]>> {
500        self.app
501            .keystrokes_for_action(self.window_id, &self.view_stack, action)
502    }
503
504    fn layout(&mut self, view_id: usize, constraint: SizeConstraint) -> Vector2F {
505        if let Some(parent_id) = self.view_stack.last() {
506            self.parents.insert(view_id, *parent_id);
507        }
508        self.view_stack.push(view_id);
509        let mut rendered_view = self.rendered_views.remove(&view_id).unwrap();
510        let size = rendered_view.layout(constraint, self);
511        self.rendered_views.insert(view_id, rendered_view);
512        self.view_stack.pop();
513        size
514    }
515
516    pub fn render<F, V, T>(&mut self, handle: &ViewHandle<V>, f: F) -> T
517    where
518        F: FnOnce(&mut V, &mut RenderContext<V>) -> T,
519        V: View,
520    {
521        handle.update(self.app, |view, cx| {
522            let mut render_cx = RenderContext {
523                app: cx,
524                window_id: handle.window_id(),
525                view_id: handle.id(),
526                view_type: PhantomData,
527                titlebar_height: self.titlebar_height,
528                hovered_region_ids: self.hovered_region_ids.clone(),
529                clicked_region_id: self.clicked_region_id,
530                right_clicked_region_id: self.right_clicked_region_id,
531                refreshing: self.refreshing,
532            };
533            f(view, &mut render_cx)
534        })
535    }
536}
537
538impl<'a> Deref for LayoutContext<'a> {
539    type Target = MutableAppContext;
540
541    fn deref(&self) -> &Self::Target {
542        self.app
543    }
544}
545
546impl<'a> DerefMut for LayoutContext<'a> {
547    fn deref_mut(&mut self) -> &mut Self::Target {
548        self.app
549    }
550}
551
552impl<'a> ReadView for LayoutContext<'a> {
553    fn read_view<T: View>(&self, handle: &ViewHandle<T>) -> &T {
554        self.app.read_view(handle)
555    }
556}
557
558impl<'a> ReadModel for LayoutContext<'a> {
559    fn read_model<T: Entity>(&self, handle: &ModelHandle<T>) -> &T {
560        self.app.read_model(handle)
561    }
562}
563
564impl<'a> UpgradeModelHandle for LayoutContext<'a> {
565    fn upgrade_model_handle<T: Entity>(
566        &self,
567        handle: &WeakModelHandle<T>,
568    ) -> Option<ModelHandle<T>> {
569        self.app.upgrade_model_handle(handle)
570    }
571
572    fn model_handle_is_upgradable<T: Entity>(&self, handle: &WeakModelHandle<T>) -> bool {
573        self.app.model_handle_is_upgradable(handle)
574    }
575
576    fn upgrade_any_model_handle(&self, handle: &AnyWeakModelHandle) -> Option<AnyModelHandle> {
577        self.app.upgrade_any_model_handle(handle)
578    }
579}
580
581impl<'a> UpgradeViewHandle for LayoutContext<'a> {
582    fn upgrade_view_handle<T: View>(&self, handle: &WeakViewHandle<T>) -> Option<ViewHandle<T>> {
583        self.app.upgrade_view_handle(handle)
584    }
585
586    fn upgrade_any_view_handle(&self, handle: &crate::AnyWeakViewHandle) -> Option<AnyViewHandle> {
587        self.app.upgrade_any_view_handle(handle)
588    }
589}
590
591pub struct PaintContext<'a> {
592    rendered_views: &'a mut HashMap<usize, ElementBox>,
593    view_stack: Vec<usize>,
594    pub scene: &'a mut Scene,
595    pub font_cache: &'a FontCache,
596    pub text_layout_cache: &'a TextLayoutCache,
597    pub app: &'a AppContext,
598}
599
600impl<'a> PaintContext<'a> {
601    fn paint(&mut self, view_id: usize, origin: Vector2F, visible_bounds: RectF) {
602        if let Some(mut tree) = self.rendered_views.remove(&view_id) {
603            self.view_stack.push(view_id);
604            tree.paint(origin, visible_bounds, self);
605            self.rendered_views.insert(view_id, tree);
606            self.view_stack.pop();
607        }
608    }
609
610    pub fn current_view_id(&self) -> usize {
611        *self.view_stack.last().unwrap()
612    }
613}
614
615impl<'a> Deref for PaintContext<'a> {
616    type Target = AppContext;
617
618    fn deref(&self) -> &Self::Target {
619        self.app
620    }
621}
622
623pub struct EventContext<'a> {
624    rendered_views: &'a mut HashMap<usize, ElementBox>,
625    dispatched_actions: Vec<DispatchDirective>,
626    pub font_cache: &'a FontCache,
627    pub text_layout_cache: &'a TextLayoutCache,
628    pub app: &'a mut MutableAppContext,
629    pub notify_count: usize,
630    view_stack: Vec<usize>,
631    invalidated_views: HashSet<usize>,
632}
633
634impl<'a> EventContext<'a> {
635    fn dispatch_event(&mut self, view_id: usize, event: &Event) -> bool {
636        if let Some(mut element) = self.rendered_views.remove(&view_id) {
637            let result =
638                self.with_current_view(view_id, |this| element.dispatch_event(event, this));
639            self.rendered_views.insert(view_id, element);
640            result
641        } else {
642            false
643        }
644    }
645
646    fn with_current_view<F, T>(&mut self, view_id: usize, f: F) -> T
647    where
648        F: FnOnce(&mut Self) -> T,
649    {
650        self.view_stack.push(view_id);
651        let result = f(self);
652        self.view_stack.pop();
653        result
654    }
655
656    pub fn dispatch_any_action(&mut self, action: Box<dyn Action>) {
657        self.dispatched_actions.push(DispatchDirective {
658            dispatcher_view_id: self.view_stack.last().copied(),
659            action,
660        });
661    }
662
663    pub fn dispatch_action<A: Action>(&mut self, action: A) {
664        self.dispatch_any_action(Box::new(action));
665    }
666
667    pub fn notify(&mut self) {
668        self.notify_count += 1;
669        if let Some(view_id) = self.view_stack.last() {
670            self.invalidated_views.insert(*view_id);
671        }
672    }
673
674    pub fn notify_count(&self) -> usize {
675        self.notify_count
676    }
677}
678
679impl<'a> Deref for EventContext<'a> {
680    type Target = MutableAppContext;
681
682    fn deref(&self) -> &Self::Target {
683        self.app
684    }
685}
686
687impl<'a> DerefMut for EventContext<'a> {
688    fn deref_mut(&mut self) -> &mut Self::Target {
689        self.app
690    }
691}
692
693pub struct DebugContext<'a> {
694    rendered_views: &'a HashMap<usize, ElementBox>,
695    pub font_cache: &'a FontCache,
696    pub app: &'a AppContext,
697}
698
699#[derive(Clone, Copy, Debug, Eq, PartialEq)]
700pub enum Axis {
701    Horizontal,
702    Vertical,
703}
704
705impl Axis {
706    pub fn invert(self) -> Self {
707        match self {
708            Self::Horizontal => Self::Vertical,
709            Self::Vertical => Self::Horizontal,
710        }
711    }
712}
713
714impl ToJson for Axis {
715    fn to_json(&self) -> serde_json::Value {
716        match self {
717            Axis::Horizontal => json!("horizontal"),
718            Axis::Vertical => json!("vertical"),
719        }
720    }
721}
722
723pub trait Vector2FExt {
724    fn along(self, axis: Axis) -> f32;
725}
726
727impl Vector2FExt for Vector2F {
728    fn along(self, axis: Axis) -> f32 {
729        match axis {
730            Axis::Horizontal => self.x(),
731            Axis::Vertical => self.y(),
732        }
733    }
734}
735
736#[derive(Copy, Clone, Debug)]
737pub struct SizeConstraint {
738    pub min: Vector2F,
739    pub max: Vector2F,
740}
741
742impl SizeConstraint {
743    pub fn new(min: Vector2F, max: Vector2F) -> Self {
744        Self { min, max }
745    }
746
747    pub fn strict(size: Vector2F) -> Self {
748        Self {
749            min: size,
750            max: size,
751        }
752    }
753
754    pub fn strict_along(axis: Axis, max: f32) -> Self {
755        match axis {
756            Axis::Horizontal => Self {
757                min: vec2f(max, 0.0),
758                max: vec2f(max, f32::INFINITY),
759            },
760            Axis::Vertical => Self {
761                min: vec2f(0.0, max),
762                max: vec2f(f32::INFINITY, max),
763            },
764        }
765    }
766
767    pub fn max_along(&self, axis: Axis) -> f32 {
768        match axis {
769            Axis::Horizontal => self.max.x(),
770            Axis::Vertical => self.max.y(),
771        }
772    }
773
774    pub fn min_along(&self, axis: Axis) -> f32 {
775        match axis {
776            Axis::Horizontal => self.min.x(),
777            Axis::Vertical => self.min.y(),
778        }
779    }
780
781    pub fn constrain(&self, size: Vector2F) -> Vector2F {
782        vec2f(
783            size.x().min(self.max.x()).max(self.min.x()),
784            size.y().min(self.max.y()).max(self.min.y()),
785        )
786    }
787}
788
789impl Default for SizeConstraint {
790    fn default() -> Self {
791        SizeConstraint {
792            min: Vector2F::zero(),
793            max: Vector2F::splat(f32::INFINITY),
794        }
795    }
796}
797
798impl ToJson for SizeConstraint {
799    fn to_json(&self) -> serde_json::Value {
800        json!({
801            "min": self.min.to_json(),
802            "max": self.max.to_json(),
803        })
804    }
805}
806
807pub struct ChildView {
808    view: AnyViewHandle,
809}
810
811impl ChildView {
812    pub fn new(view: impl Into<AnyViewHandle>) -> Self {
813        Self { view: view.into() }
814    }
815}
816
817impl Element for ChildView {
818    type LayoutState = ();
819    type PaintState = ();
820
821    fn layout(
822        &mut self,
823        constraint: SizeConstraint,
824        cx: &mut LayoutContext,
825    ) -> (Vector2F, Self::LayoutState) {
826        let size = cx.layout(self.view.id(), constraint);
827        (size, ())
828    }
829
830    fn paint(
831        &mut self,
832        bounds: RectF,
833        visible_bounds: RectF,
834        _: &mut Self::LayoutState,
835        cx: &mut PaintContext,
836    ) -> Self::PaintState {
837        cx.paint(self.view.id(), bounds.origin(), visible_bounds);
838    }
839
840    fn dispatch_event(
841        &mut self,
842        event: &Event,
843        _: RectF,
844        _: RectF,
845        _: &mut Self::LayoutState,
846        _: &mut Self::PaintState,
847        cx: &mut EventContext,
848    ) -> bool {
849        cx.dispatch_event(self.view.id(), event)
850    }
851
852    fn debug(
853        &self,
854        bounds: RectF,
855        _: &Self::LayoutState,
856        _: &Self::PaintState,
857        cx: &DebugContext,
858    ) -> serde_json::Value {
859        json!({
860            "type": "ChildView",
861            "view_id": self.view.id(),
862            "bounds": bounds.to_json(),
863            "view": self.view.debug_json(cx.app),
864            "child": if let Some(view) = cx.rendered_views.get(&self.view.id()) {
865                view.debug(cx)
866            } else {
867                json!(null)
868            }
869        })
870    }
871}