presenter.rs

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