presenter.rs

  1use crate::{
  2    app::{AppContext, MutableAppContext, WindowInvalidation},
  3    elements::Element,
  4    font_cache::FontCache,
  5    json::{self, ToJson},
  6    platform::Event,
  7    text_layout::TextLayoutCache,
  8    Action, AnyAction, AssetCache, ElementBox, Scene,
  9};
 10use pathfinder_geometry::vector::{vec2f, Vector2F};
 11use serde_json::json;
 12use std::{
 13    collections::{HashMap, HashSet},
 14    sync::Arc,
 15};
 16
 17pub struct Presenter {
 18    window_id: usize,
 19    rendered_views: HashMap<usize, ElementBox>,
 20    parents: HashMap<usize, usize>,
 21    font_cache: Arc<FontCache>,
 22    text_layout_cache: TextLayoutCache,
 23    asset_cache: Arc<AssetCache>,
 24    last_mouse_moved_event: Option<Event>,
 25}
 26
 27impl Presenter {
 28    pub fn new(
 29        window_id: usize,
 30        titlebar_height: f32,
 31        font_cache: Arc<FontCache>,
 32        text_layout_cache: TextLayoutCache,
 33        asset_cache: Arc<AssetCache>,
 34        cx: &MutableAppContext,
 35    ) -> Self {
 36        Self {
 37            window_id,
 38            rendered_views: cx.render_views(window_id, titlebar_height),
 39            parents: HashMap::new(),
 40            font_cache,
 41            text_layout_cache,
 42            asset_cache,
 43            last_mouse_moved_event: None,
 44        }
 45    }
 46
 47    pub fn dispatch_path(&self, app: &AppContext) -> Vec<usize> {
 48        let mut view_id = app.focused_view_id(self.window_id).unwrap();
 49        let mut path = vec![view_id];
 50        while let Some(parent_id) = self.parents.get(&view_id).copied() {
 51            path.push(parent_id);
 52            view_id = parent_id;
 53        }
 54        path.reverse();
 55        path
 56    }
 57
 58    pub fn invalidate(
 59        &mut self,
 60        mut invalidation: WindowInvalidation,
 61        titlebar_height: f32,
 62        cx: &AppContext,
 63    ) {
 64        for view_id in invalidation.removed {
 65            invalidation.updated.remove(&view_id);
 66            self.rendered_views.remove(&view_id);
 67            self.parents.remove(&view_id);
 68        }
 69        for view_id in invalidation.updated {
 70            self.rendered_views.insert(
 71                view_id,
 72                cx.render_view(self.window_id, view_id, titlebar_height)
 73                    .unwrap(),
 74            );
 75        }
 76    }
 77
 78    pub fn build_scene(
 79        &mut self,
 80        window_size: Vector2F,
 81        titlebar_height: f32,
 82        scale_factor: f32,
 83        cx: &mut MutableAppContext,
 84    ) -> Scene {
 85        let mut scene = Scene::new(scale_factor);
 86
 87        if let Some(root_view_id) = cx.root_view_id(self.window_id) {
 88            self.layout(window_size, titlebar_height, cx);
 89            self.after_layout(cx);
 90            let mut paint_cx = PaintContext {
 91                scene: &mut scene,
 92                font_cache: &self.font_cache,
 93                text_layout_cache: &self.text_layout_cache,
 94                rendered_views: &mut self.rendered_views,
 95                app: cx.as_ref(),
 96            };
 97            paint_cx.paint(root_view_id, Vector2F::zero());
 98            self.text_layout_cache.finish_frame();
 99
100            if let Some(event) = self.last_mouse_moved_event.clone() {
101                self.dispatch_event(event, cx)
102            }
103        } else {
104            log::error!("could not find root_view_id for window {}", self.window_id);
105        }
106
107        scene
108    }
109
110    fn layout(&mut self, size: Vector2F, titlebar_height: f32, cx: &mut MutableAppContext) {
111        if let Some(root_view_id) = cx.root_view_id(self.window_id) {
112            let mut layout_ctx = LayoutContext {
113                rendered_views: &mut self.rendered_views,
114                parents: &mut self.parents,
115                font_cache: &self.font_cache,
116                text_layout_cache: &self.text_layout_cache,
117                asset_cache: &self.asset_cache,
118                view_stack: Vec::new(),
119                app: cx,
120                titlebar_height,
121            };
122            layout_ctx.layout(root_view_id, SizeConstraint::strict(size));
123        }
124    }
125
126    fn after_layout(&mut self, cx: &mut MutableAppContext) {
127        if let Some(root_view_id) = cx.root_view_id(self.window_id) {
128            let mut layout_cx = AfterLayoutContext {
129                rendered_views: &mut self.rendered_views,
130                font_cache: &self.font_cache,
131                text_layout_cache: &self.text_layout_cache,
132                app: cx,
133            };
134            layout_cx.after_layout(root_view_id);
135        }
136    }
137
138    pub fn dispatch_event(&mut self, event: Event, cx: &mut MutableAppContext) {
139        if let Some(root_view_id) = cx.root_view_id(self.window_id) {
140            if matches!(event, Event::MouseMoved { .. }) {
141                self.last_mouse_moved_event = Some(event.clone());
142            }
143
144            let mut event_cx = EventContext {
145                rendered_views: &mut self.rendered_views,
146                dispatched_actions: Default::default(),
147                font_cache: &self.font_cache,
148                text_layout_cache: &self.text_layout_cache,
149                view_stack: Default::default(),
150                invalidated_views: Default::default(),
151                app: cx,
152            };
153            event_cx.dispatch_event(root_view_id, &event);
154
155            let invalidated_views = event_cx.invalidated_views;
156            let dispatch_directives = event_cx.dispatched_actions;
157
158            for view_id in invalidated_views {
159                cx.notify_view(self.window_id, view_id);
160            }
161            for directive in dispatch_directives {
162                cx.dispatch_action_any(self.window_id, &directive.path, directive.action.as_ref());
163            }
164        }
165    }
166
167    pub fn debug_elements(&self, cx: &AppContext) -> Option<json::Value> {
168        cx.root_view_id(self.window_id)
169            .and_then(|root_view_id| self.rendered_views.get(&root_view_id))
170            .map(|root_element| {
171                root_element.debug(&DebugContext {
172                    rendered_views: &self.rendered_views,
173                    font_cache: &self.font_cache,
174                    app: cx,
175                })
176            })
177    }
178}
179
180pub struct DispatchDirective {
181    pub path: Vec<usize>,
182    pub action: Box<dyn AnyAction>,
183}
184
185pub struct LayoutContext<'a> {
186    rendered_views: &'a mut HashMap<usize, ElementBox>,
187    parents: &'a mut HashMap<usize, usize>,
188    pub font_cache: &'a FontCache,
189    pub text_layout_cache: &'a TextLayoutCache,
190    pub asset_cache: &'a AssetCache,
191    pub app: &'a mut MutableAppContext,
192    view_stack: Vec<usize>,
193    pub titlebar_height: f32,
194}
195
196impl<'a> LayoutContext<'a> {
197    fn layout(&mut self, view_id: usize, constraint: SizeConstraint) -> Vector2F {
198        if let Some(parent_id) = self.view_stack.last() {
199            self.parents.insert(view_id, *parent_id);
200        }
201        self.view_stack.push(view_id);
202        let mut rendered_view = self.rendered_views.remove(&view_id).unwrap();
203        let size = rendered_view.layout(constraint, self);
204        self.rendered_views.insert(view_id, rendered_view);
205        self.view_stack.pop();
206        size
207    }
208}
209
210pub struct AfterLayoutContext<'a> {
211    rendered_views: &'a mut HashMap<usize, ElementBox>,
212    pub font_cache: &'a FontCache,
213    pub text_layout_cache: &'a TextLayoutCache,
214    pub app: &'a mut MutableAppContext,
215}
216
217impl<'a> AfterLayoutContext<'a> {
218    fn after_layout(&mut self, view_id: usize) {
219        if let Some(mut view) = self.rendered_views.remove(&view_id) {
220            view.after_layout(self);
221            self.rendered_views.insert(view_id, view);
222        }
223    }
224}
225
226pub struct PaintContext<'a> {
227    rendered_views: &'a mut HashMap<usize, ElementBox>,
228    pub scene: &'a mut Scene,
229    pub font_cache: &'a FontCache,
230    pub text_layout_cache: &'a TextLayoutCache,
231    pub app: &'a AppContext,
232}
233
234impl<'a> PaintContext<'a> {
235    fn paint(&mut self, view_id: usize, origin: Vector2F) {
236        if let Some(mut tree) = self.rendered_views.remove(&view_id) {
237            tree.paint(origin, self);
238            self.rendered_views.insert(view_id, tree);
239        }
240    }
241}
242
243pub struct EventContext<'a> {
244    rendered_views: &'a mut HashMap<usize, ElementBox>,
245    dispatched_actions: Vec<DispatchDirective>,
246    pub font_cache: &'a FontCache,
247    pub text_layout_cache: &'a TextLayoutCache,
248    pub app: &'a mut MutableAppContext,
249    view_stack: Vec<usize>,
250    invalidated_views: HashSet<usize>,
251}
252
253impl<'a> EventContext<'a> {
254    fn dispatch_event(&mut self, view_id: usize, event: &Event) -> bool {
255        if let Some(mut element) = self.rendered_views.remove(&view_id) {
256            self.view_stack.push(view_id);
257            let result = element.dispatch_event(event, self);
258            self.view_stack.pop();
259            self.rendered_views.insert(view_id, element);
260            result
261        } else {
262            false
263        }
264    }
265
266    pub fn dispatch_action<A: Action>(&mut self, action: A) {
267        self.dispatched_actions.push(DispatchDirective {
268            path: self.view_stack.clone(),
269            action: Box::new(action),
270        });
271    }
272
273    pub fn notify(&mut self) {
274        self.invalidated_views
275            .insert(*self.view_stack.last().unwrap());
276    }
277}
278
279pub struct DebugContext<'a> {
280    rendered_views: &'a HashMap<usize, ElementBox>,
281    pub font_cache: &'a FontCache,
282    pub app: &'a AppContext,
283}
284
285#[derive(Clone, Copy, Debug, Eq, PartialEq)]
286pub enum Axis {
287    Horizontal,
288    Vertical,
289}
290
291impl Axis {
292    pub fn invert(self) -> Self {
293        match self {
294            Self::Horizontal => Self::Vertical,
295            Self::Vertical => Self::Horizontal,
296        }
297    }
298}
299
300impl ToJson for Axis {
301    fn to_json(&self) -> serde_json::Value {
302        match self {
303            Axis::Horizontal => json!("horizontal"),
304            Axis::Vertical => json!("vertical"),
305        }
306    }
307}
308
309pub trait Vector2FExt {
310    fn along(self, axis: Axis) -> f32;
311}
312
313impl Vector2FExt for Vector2F {
314    fn along(self, axis: Axis) -> f32 {
315        match axis {
316            Axis::Horizontal => self.x(),
317            Axis::Vertical => self.y(),
318        }
319    }
320}
321
322#[derive(Copy, Clone, Debug)]
323pub struct SizeConstraint {
324    pub min: Vector2F,
325    pub max: Vector2F,
326}
327
328impl SizeConstraint {
329    pub fn new(min: Vector2F, max: Vector2F) -> Self {
330        Self { min, max }
331    }
332
333    pub fn strict(size: Vector2F) -> Self {
334        Self {
335            min: size,
336            max: size,
337        }
338    }
339
340    pub fn strict_along(axis: Axis, max: f32) -> Self {
341        match axis {
342            Axis::Horizontal => Self {
343                min: vec2f(max, 0.0),
344                max: vec2f(max, f32::INFINITY),
345            },
346            Axis::Vertical => Self {
347                min: vec2f(0.0, max),
348                max: vec2f(f32::INFINITY, max),
349            },
350        }
351    }
352
353    pub fn max_along(&self, axis: Axis) -> f32 {
354        match axis {
355            Axis::Horizontal => self.max.x(),
356            Axis::Vertical => self.max.y(),
357        }
358    }
359}
360
361impl ToJson for SizeConstraint {
362    fn to_json(&self) -> serde_json::Value {
363        json!({
364            "min": self.min.to_json(),
365            "max": self.max.to_json(),
366        })
367    }
368}
369
370pub struct ChildView {
371    view_id: usize,
372}
373
374impl ChildView {
375    pub fn new(view_id: usize) -> Self {
376        Self { view_id }
377    }
378}
379
380impl Element for ChildView {
381    type LayoutState = ();
382    type PaintState = ();
383
384    fn layout(
385        &mut self,
386        constraint: SizeConstraint,
387        cx: &mut LayoutContext,
388    ) -> (Vector2F, Self::LayoutState) {
389        let size = cx.layout(self.view_id, constraint);
390        (size, ())
391    }
392
393    fn paint(
394        &mut self,
395        bounds: pathfinder_geometry::rect::RectF,
396        _: &mut Self::LayoutState,
397        cx: &mut PaintContext,
398    ) -> Self::PaintState {
399        cx.paint(self.view_id, bounds.origin());
400    }
401
402    fn dispatch_event(
403        &mut self,
404        event: &Event,
405        _: pathfinder_geometry::rect::RectF,
406        _: &mut Self::LayoutState,
407        _: &mut Self::PaintState,
408        cx: &mut EventContext,
409    ) -> bool {
410        cx.dispatch_event(self.view_id, event)
411    }
412
413    fn debug(
414        &self,
415        bounds: pathfinder_geometry::rect::RectF,
416        _: &Self::LayoutState,
417        _: &Self::PaintState,
418        cx: &DebugContext,
419    ) -> serde_json::Value {
420        json!({
421            "type": "ChildView",
422            "view_id": self.view_id,
423            "bounds": bounds.to_json(),
424            "child": if let Some(view) = cx.rendered_views.get(&self.view_id) {
425                view.debug(cx)
426            } else {
427                json!(null)
428            }
429        })
430    }
431}
432
433#[cfg(test)]
434mod tests {
435    // #[test]
436    // fn test_responder_chain() {
437    //     let settings = settings_rx(None);
438    //     let mut app = App::new().unwrap();
439    //     let workspace = app.add_model(|cx| Workspace::new(Vec::new(), cx));
440    //     let (window_id, workspace_view) =
441    //         app.add_window(|cx| WorkspaceView::new(workspace.clone(), settings, cx));
442
443    //     let invalidations = Rc::new(RefCell::new(Vec::new()));
444    //     let invalidations_ = invalidations.clone();
445    //     app.on_window_invalidated(window_id, move |invalidation, _| {
446    //         invalidations_.borrow_mut().push(invalidation)
447    //     });
448
449    //     let active_pane_id = workspace_view.update(&mut app, |view, cx| {
450    //         cx.focus(view.active_pane());
451    //         view.active_pane().id()
452    //     });
453
454    //     app.update(|app| {
455    //         let mut presenter = Presenter::new(
456    //             window_id,
457    //             Rc::new(FontCache::new()),
458    //             Rc::new(AssetCache::new()),
459    //             app,
460    //         );
461    //         for invalidation in invalidations.borrow().iter().cloned() {
462    //             presenter.update(vec2f(1024.0, 768.0), 2.0, Some(invalidation), app);
463    //         }
464
465    //         assert_eq!(
466    //             presenter.responder_chain(app.cx()).unwrap(),
467    //             vec![workspace_view.id(), active_pane_id]
468    //         );
469    //     });
470    // }
471}