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