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, FontSystem, Scene,
  9};
 10use pathfinder_geometry::vector::{vec2f, Vector2F};
 11use serde_json::json;
 12use std::{
 13    collections::{HashMap, HashSet},
 14    ops::{Deref, DerefMut},
 15    sync::Arc,
 16};
 17
 18pub struct Presenter {
 19    window_id: usize,
 20    rendered_views: HashMap<usize, ElementBox>,
 21    parents: HashMap<usize, usize>,
 22    font_cache: Arc<FontCache>,
 23    text_layout_cache: TextLayoutCache,
 24    asset_cache: Arc<AssetCache>,
 25    last_mouse_moved_event: Option<Event>,
 26    titlebar_height: f32,
 27}
 28
 29impl Presenter {
 30    pub fn new(
 31        window_id: usize,
 32        titlebar_height: f32,
 33        font_cache: Arc<FontCache>,
 34        text_layout_cache: TextLayoutCache,
 35        asset_cache: Arc<AssetCache>,
 36        cx: &mut MutableAppContext,
 37    ) -> Self {
 38        Self {
 39            window_id,
 40            rendered_views: cx.render_views(window_id, titlebar_height),
 41            parents: HashMap::new(),
 42            font_cache,
 43            text_layout_cache,
 44            asset_cache,
 45            last_mouse_moved_event: None,
 46            titlebar_height,
 47        }
 48    }
 49
 50    pub fn dispatch_path(&self, app: &AppContext) -> Vec<usize> {
 51        let mut view_id = app.focused_view_id(self.window_id).unwrap();
 52        let mut path = vec![view_id];
 53        while let Some(parent_id) = self.parents.get(&view_id).copied() {
 54            path.push(parent_id);
 55            view_id = parent_id;
 56        }
 57        path.reverse();
 58        path
 59    }
 60
 61    pub fn invalidate(&mut self, mut invalidation: WindowInvalidation, cx: &mut MutableAppContext) {
 62        for view_id in invalidation.removed {
 63            invalidation.updated.remove(&view_id);
 64            self.rendered_views.remove(&view_id);
 65            self.parents.remove(&view_id);
 66        }
 67        for view_id in invalidation.updated {
 68            self.rendered_views.insert(
 69                view_id,
 70                cx.render_view(self.window_id, view_id, self.titlebar_height, false)
 71                    .unwrap(),
 72            );
 73        }
 74    }
 75
 76    pub fn refresh(
 77        &mut self,
 78        invalidation: Option<WindowInvalidation>,
 79        cx: &mut MutableAppContext,
 80    ) {
 81        if let Some(invalidation) = invalidation {
 82            for view_id in invalidation.removed {
 83                self.rendered_views.remove(&view_id);
 84                self.parents.remove(&view_id);
 85            }
 86        }
 87
 88        for (view_id, view) in &mut self.rendered_views {
 89            *view = cx
 90                .render_view(self.window_id, *view_id, self.titlebar_height, true)
 91                .unwrap();
 92        }
 93    }
 94
 95    pub fn build_scene(
 96        &mut self,
 97        window_size: Vector2F,
 98        scale_factor: f32,
 99        cx: &mut MutableAppContext,
100    ) -> Scene {
101        let mut scene = Scene::new(scale_factor);
102
103        if let Some(root_view_id) = cx.root_view_id(self.window_id) {
104            self.layout(window_size, cx);
105            let mut paint_cx = PaintContext {
106                scene: &mut scene,
107                font_cache: &self.font_cache,
108                text_layout_cache: &self.text_layout_cache,
109                rendered_views: &mut self.rendered_views,
110                app: cx.as_ref(),
111            };
112            paint_cx.paint(root_view_id, Vector2F::zero());
113            self.text_layout_cache.finish_frame();
114
115            if let Some(event) = self.last_mouse_moved_event.clone() {
116                self.dispatch_event(event, cx)
117            }
118        } else {
119            log::error!("could not find root_view_id for window {}", self.window_id);
120        }
121
122        scene
123    }
124
125    fn layout(&mut self, size: Vector2F, cx: &mut MutableAppContext) {
126        if let Some(root_view_id) = cx.root_view_id(self.window_id) {
127            self.layout_cx(cx)
128                .layout(root_view_id, SizeConstraint::strict(size));
129        }
130    }
131
132    pub fn layout_cx<'a>(&'a mut self, cx: &'a mut MutableAppContext) -> LayoutContext<'a> {
133        LayoutContext {
134            rendered_views: &mut self.rendered_views,
135            parents: &mut self.parents,
136            font_cache: &self.font_cache,
137            font_system: cx.platform().fonts(),
138            text_layout_cache: &self.text_layout_cache,
139            asset_cache: &self.asset_cache,
140            view_stack: Vec::new(),
141            app: cx,
142        }
143    }
144
145    pub fn dispatch_event(&mut self, event: Event, cx: &mut MutableAppContext) {
146        if let Some(root_view_id) = cx.root_view_id(self.window_id) {
147            match event {
148                Event::MouseMoved { position, .. } | Event::LeftMouseDragged { position } => {
149                    self.last_mouse_moved_event = Some(Event::MouseMoved { position });
150                }
151                _ => {}
152            }
153
154            let mut event_cx = EventContext {
155                rendered_views: &mut self.rendered_views,
156                dispatched_actions: Default::default(),
157                font_cache: &self.font_cache,
158                text_layout_cache: &self.text_layout_cache,
159                view_stack: Default::default(),
160                invalidated_views: Default::default(),
161                app: cx,
162            };
163            event_cx.dispatch_event(root_view_id, &event);
164
165            let invalidated_views = event_cx.invalidated_views;
166            let dispatch_directives = event_cx.dispatched_actions;
167
168            for view_id in invalidated_views {
169                cx.notify_view(self.window_id, view_id);
170            }
171            for directive in dispatch_directives {
172                cx.dispatch_action_any(self.window_id, &directive.path, directive.action.as_ref());
173            }
174        }
175    }
176
177    pub fn debug_elements(&self, cx: &AppContext) -> Option<json::Value> {
178        cx.root_view_id(self.window_id)
179            .and_then(|root_view_id| self.rendered_views.get(&root_view_id))
180            .map(|root_element| {
181                root_element.debug(&DebugContext {
182                    rendered_views: &self.rendered_views,
183                    font_cache: &self.font_cache,
184                    app: cx,
185                })
186            })
187    }
188}
189
190pub struct DispatchDirective {
191    pub path: Vec<usize>,
192    pub action: Box<dyn AnyAction>,
193}
194
195pub struct LayoutContext<'a> {
196    rendered_views: &'a mut HashMap<usize, ElementBox>,
197    parents: &'a mut HashMap<usize, usize>,
198    view_stack: Vec<usize>,
199    pub font_cache: &'a Arc<FontCache>,
200    pub font_system: Arc<dyn FontSystem>,
201    pub text_layout_cache: &'a TextLayoutCache,
202    pub asset_cache: &'a AssetCache,
203    pub app: &'a mut MutableAppContext,
204}
205
206impl<'a> LayoutContext<'a> {
207    fn layout(&mut self, view_id: usize, constraint: SizeConstraint) -> Vector2F {
208        if let Some(parent_id) = self.view_stack.last() {
209            self.parents.insert(view_id, *parent_id);
210        }
211        self.view_stack.push(view_id);
212        let mut rendered_view = self.rendered_views.remove(&view_id).unwrap();
213        let size = rendered_view.layout(constraint, self);
214        self.rendered_views.insert(view_id, rendered_view);
215        self.view_stack.pop();
216        size
217    }
218}
219
220pub struct PaintContext<'a> {
221    rendered_views: &'a mut HashMap<usize, ElementBox>,
222    pub scene: &'a mut Scene,
223    pub font_cache: &'a FontCache,
224    pub text_layout_cache: &'a TextLayoutCache,
225    pub app: &'a AppContext,
226}
227
228impl<'a> PaintContext<'a> {
229    fn paint(&mut self, view_id: usize, origin: Vector2F) {
230        if let Some(mut tree) = self.rendered_views.remove(&view_id) {
231            tree.paint(origin, self);
232            self.rendered_views.insert(view_id, tree);
233        }
234    }
235}
236
237pub struct EventContext<'a> {
238    rendered_views: &'a mut HashMap<usize, ElementBox>,
239    dispatched_actions: Vec<DispatchDirective>,
240    pub font_cache: &'a FontCache,
241    pub text_layout_cache: &'a TextLayoutCache,
242    pub app: &'a mut MutableAppContext,
243    view_stack: Vec<usize>,
244    invalidated_views: HashSet<usize>,
245}
246
247impl<'a> EventContext<'a> {
248    fn dispatch_event(&mut self, view_id: usize, event: &Event) -> bool {
249        if let Some(mut element) = self.rendered_views.remove(&view_id) {
250            self.view_stack.push(view_id);
251            let result = element.dispatch_event(event, self);
252            self.view_stack.pop();
253            self.rendered_views.insert(view_id, element);
254            result
255        } else {
256            false
257        }
258    }
259
260    pub fn dispatch_action<A: Action>(&mut self, action: A) {
261        self.dispatched_actions.push(DispatchDirective {
262            path: self.view_stack.clone(),
263            action: Box::new(action),
264        });
265    }
266
267    pub fn notify(&mut self) {
268        self.invalidated_views
269            .insert(*self.view_stack.last().unwrap());
270    }
271}
272
273impl<'a> Deref for EventContext<'a> {
274    type Target = MutableAppContext;
275
276    fn deref(&self) -> &Self::Target {
277        self.app
278    }
279}
280
281impl<'a> DerefMut for EventContext<'a> {
282    fn deref_mut(&mut self) -> &mut Self::Target {
283        self.app
284    }
285}
286
287pub struct DebugContext<'a> {
288    rendered_views: &'a HashMap<usize, ElementBox>,
289    pub font_cache: &'a FontCache,
290    pub app: &'a AppContext,
291}
292
293#[derive(Clone, Copy, Debug, Eq, PartialEq)]
294pub enum Axis {
295    Horizontal,
296    Vertical,
297}
298
299impl Axis {
300    pub fn invert(self) -> Self {
301        match self {
302            Self::Horizontal => Self::Vertical,
303            Self::Vertical => Self::Horizontal,
304        }
305    }
306}
307
308impl ToJson for Axis {
309    fn to_json(&self) -> serde_json::Value {
310        match self {
311            Axis::Horizontal => json!("horizontal"),
312            Axis::Vertical => json!("vertical"),
313        }
314    }
315}
316
317pub trait Vector2FExt {
318    fn along(self, axis: Axis) -> f32;
319}
320
321impl Vector2FExt for Vector2F {
322    fn along(self, axis: Axis) -> f32 {
323        match axis {
324            Axis::Horizontal => self.x(),
325            Axis::Vertical => self.y(),
326        }
327    }
328}
329
330#[derive(Copy, Clone, Debug)]
331pub struct SizeConstraint {
332    pub min: Vector2F,
333    pub max: Vector2F,
334}
335
336impl SizeConstraint {
337    pub fn new(min: Vector2F, max: Vector2F) -> Self {
338        Self { min, max }
339    }
340
341    pub fn strict(size: Vector2F) -> Self {
342        Self {
343            min: size,
344            max: size,
345        }
346    }
347
348    pub fn strict_along(axis: Axis, max: f32) -> Self {
349        match axis {
350            Axis::Horizontal => Self {
351                min: vec2f(max, 0.0),
352                max: vec2f(max, f32::INFINITY),
353            },
354            Axis::Vertical => Self {
355                min: vec2f(0.0, max),
356                max: vec2f(f32::INFINITY, max),
357            },
358        }
359    }
360
361    pub fn max_along(&self, axis: Axis) -> f32 {
362        match axis {
363            Axis::Horizontal => self.max.x(),
364            Axis::Vertical => self.max.y(),
365        }
366    }
367
368    pub fn min_along(&self, axis: Axis) -> f32 {
369        match axis {
370            Axis::Horizontal => self.min.x(),
371            Axis::Vertical => self.min.y(),
372        }
373    }
374}
375
376impl ToJson for SizeConstraint {
377    fn to_json(&self) -> serde_json::Value {
378        json!({
379            "min": self.min.to_json(),
380            "max": self.max.to_json(),
381        })
382    }
383}
384
385pub struct ChildView {
386    view_id: usize,
387}
388
389impl ChildView {
390    pub fn new(view_id: usize) -> Self {
391        Self { view_id }
392    }
393}
394
395impl Element for ChildView {
396    type LayoutState = ();
397    type PaintState = ();
398
399    fn layout(
400        &mut self,
401        constraint: SizeConstraint,
402        cx: &mut LayoutContext,
403    ) -> (Vector2F, Self::LayoutState) {
404        let size = cx.layout(self.view_id, constraint);
405        (size, ())
406    }
407
408    fn paint(
409        &mut self,
410        bounds: pathfinder_geometry::rect::RectF,
411        _: &mut Self::LayoutState,
412        cx: &mut PaintContext,
413    ) -> Self::PaintState {
414        cx.paint(self.view_id, bounds.origin());
415    }
416
417    fn dispatch_event(
418        &mut self,
419        event: &Event,
420        _: pathfinder_geometry::rect::RectF,
421        _: &mut Self::LayoutState,
422        _: &mut Self::PaintState,
423        cx: &mut EventContext,
424    ) -> bool {
425        cx.dispatch_event(self.view_id, event)
426    }
427
428    fn debug(
429        &self,
430        bounds: pathfinder_geometry::rect::RectF,
431        _: &Self::LayoutState,
432        _: &Self::PaintState,
433        cx: &DebugContext,
434    ) -> serde_json::Value {
435        json!({
436            "type": "ChildView",
437            "view_id": self.view_id,
438            "bounds": bounds.to_json(),
439            "child": if let Some(view) = cx.rendered_views.get(&self.view_id) {
440                view.debug(cx)
441            } else {
442                json!(null)
443            }
444        })
445    }
446}
447
448#[cfg(test)]
449mod tests {
450    // #[test]
451    // fn test_responder_chain() {
452    //     let settings = settings_rx(None);
453    //     let mut app = App::new().unwrap();
454    //     let workspace = app.add_model(|cx| Workspace::new(Vec::new(), cx));
455    //     let (window_id, workspace_view) =
456    //         app.add_window(|cx| WorkspaceView::new(workspace.clone(), settings, cx));
457
458    //     let invalidations = Rc::new(RefCell::new(Vec::new()));
459    //     let invalidations_ = invalidations.clone();
460    //     app.on_window_invalidated(window_id, move |invalidation, _| {
461    //         invalidations_.borrow_mut().push(invalidation)
462    //     });
463
464    //     let active_pane_id = workspace_view.update(&mut app, |view, cx| {
465    //         cx.focus(view.active_pane());
466    //         view.active_pane().id()
467    //     });
468
469    //     app.update(|app| {
470    //         let mut presenter = Presenter::new(
471    //             window_id,
472    //             Rc::new(FontCache::new()),
473    //             Rc::new(AssetCache::new()),
474    //             app,
475    //         );
476    //         for invalidation in invalidations.borrow().iter().cloned() {
477    //             presenter.update(vec2f(1024.0, 768.0), 2.0, Some(invalidation), app);
478    //         }
479
480    //         assert_eq!(
481    //             presenter.responder_chain(app.cx()).unwrap(),
482    //             vec![workspace_view.id(), active_pane_id]
483    //         );
484    //     });
485    // }
486}