1use crate::{
2 px, size, Action, AnyBox, AnyDrag, AnyView, AppContext, AsyncWindowContext, AvailableSpace,
3 Bounds, BoxShadow, Context, Corners, DevicePixels, DispatchContext, DisplayId, Edges, Effect,
4 Entity, EntityId, EventEmitter, FileDropEvent, FocusEvent, FontId, GlobalElementId, GlyphId,
5 Hsla, ImageData, InputEvent, IsZero, KeyListener, KeyMatch, KeyMatcher, Keystroke, LayoutId,
6 MainThread, MainThreadOnly, Model, ModelContext, Modifiers, MonochromeSprite, MouseButton,
7 MouseDownEvent, MouseMoveEvent, MouseUpEvent, Path, Pixels, PlatformAtlas, PlatformWindow,
8 Point, PolychromeSprite, Quad, RenderGlyphParams, RenderImageParams, RenderSvgParams,
9 ScaledPixels, SceneBuilder, Shadow, SharedString, Size, Style, Subscription, TaffyLayoutEngine,
10 Task, Underline, UnderlineStyle, View, VisualContext, WeakView, WindowOptions,
11 SUBPIXEL_VARIANTS,
12};
13use anyhow::Result;
14use collections::HashMap;
15use derive_more::{Deref, DerefMut};
16use parking_lot::RwLock;
17use slotmap::SlotMap;
18use smallvec::SmallVec;
19use std::{
20 any::{Any, TypeId},
21 borrow::{Borrow, BorrowMut, Cow},
22 fmt::Debug,
23 future::Future,
24 marker::PhantomData,
25 mem,
26 sync::{
27 atomic::{AtomicUsize, Ordering::SeqCst},
28 Arc,
29 },
30};
31use util::ResultExt;
32
33/// A global stacking order, which is created by stacking successive z-index values.
34/// Each z-index will always be interpreted in the context of its parent z-index.
35#[derive(Deref, DerefMut, Ord, PartialOrd, Eq, PartialEq, Clone, Default)]
36pub(crate) struct StackingOrder(pub(crate) SmallVec<[u32; 16]>);
37
38/// Represents the two different phases when dispatching events.
39#[derive(Default, Copy, Clone, Debug, Eq, PartialEq)]
40pub enum DispatchPhase {
41 /// After the capture phase comes the bubble phase, in which mouse event listeners are
42 /// invoked front to back and keyboard event listeners are invoked from the focused element
43 /// to the root of the element tree. This is the phase you'll most commonly want to use when
44 /// registering event listeners.
45 #[default]
46 Bubble,
47 /// During the initial capture phase, mouse event listeners are invoked back to front, and keyboard
48 /// listeners are invoked from the root of the tree downward toward the focused element. This phase
49 /// is used for special purposes such as clearing the "pressed" state for click events. If
50 /// you stop event propagation during this phase, you need to know what you're doing. Handlers
51 /// outside of the immediate region may rely on detecting non-local events during this phase.
52 Capture,
53}
54
55type AnyListener = Box<dyn Fn(&dyn Any, DispatchPhase, &mut WindowContext) + Send + 'static>;
56type AnyKeyListener = Box<
57 dyn Fn(
58 &dyn Any,
59 &[&DispatchContext],
60 DispatchPhase,
61 &mut WindowContext,
62 ) -> Option<Box<dyn Action>>
63 + Send
64 + 'static,
65>;
66type AnyFocusListener = Box<dyn Fn(&FocusEvent, &mut WindowContext) + Send + 'static>;
67
68slotmap::new_key_type! { pub struct FocusId; }
69
70/// A handle which can be used to track and manipulate the focused element in a window.
71pub struct FocusHandle {
72 pub(crate) id: FocusId,
73 handles: Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>,
74}
75
76impl FocusHandle {
77 pub(crate) fn new(handles: &Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>) -> Self {
78 let id = handles.write().insert(AtomicUsize::new(1));
79 Self {
80 id,
81 handles: handles.clone(),
82 }
83 }
84
85 pub(crate) fn for_id(
86 id: FocusId,
87 handles: &Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>,
88 ) -> Option<Self> {
89 let lock = handles.read();
90 let ref_count = lock.get(id)?;
91 if ref_count.load(SeqCst) == 0 {
92 None
93 } else {
94 ref_count.fetch_add(1, SeqCst);
95 Some(Self {
96 id,
97 handles: handles.clone(),
98 })
99 }
100 }
101
102 /// Obtains whether the element associated with this handle is currently focused.
103 pub fn is_focused(&self, cx: &WindowContext) -> bool {
104 cx.window.focus == Some(self.id)
105 }
106
107 /// Obtains whether the element associated with this handle contains the focused
108 /// element or is itself focused.
109 pub fn contains_focused(&self, cx: &WindowContext) -> bool {
110 cx.focused()
111 .map_or(false, |focused| self.contains(&focused, cx))
112 }
113
114 /// Obtains whether the element associated with this handle is contained within the
115 /// focused element or is itself focused.
116 pub fn within_focused(&self, cx: &WindowContext) -> bool {
117 let focused = cx.focused();
118 focused.map_or(false, |focused| focused.contains(self, cx))
119 }
120
121 /// Obtains whether this handle contains the given handle in the most recently rendered frame.
122 pub(crate) fn contains(&self, other: &Self, cx: &WindowContext) -> bool {
123 let mut ancestor = Some(other.id);
124 while let Some(ancestor_id) = ancestor {
125 if self.id == ancestor_id {
126 return true;
127 } else {
128 ancestor = cx.window.focus_parents_by_child.get(&ancestor_id).copied();
129 }
130 }
131 false
132 }
133}
134
135impl Clone for FocusHandle {
136 fn clone(&self) -> Self {
137 Self::for_id(self.id, &self.handles).unwrap()
138 }
139}
140
141impl PartialEq for FocusHandle {
142 fn eq(&self, other: &Self) -> bool {
143 self.id == other.id
144 }
145}
146
147impl Eq for FocusHandle {}
148
149impl Drop for FocusHandle {
150 fn drop(&mut self) {
151 self.handles
152 .read()
153 .get(self.id)
154 .unwrap()
155 .fetch_sub(1, SeqCst);
156 }
157}
158
159// Holds the state for a specific window.
160pub struct Window {
161 pub(crate) handle: AnyWindowHandle,
162 platform_window: MainThreadOnly<Box<dyn PlatformWindow>>,
163 display_id: DisplayId,
164 sprite_atlas: Arc<dyn PlatformAtlas>,
165 rem_size: Pixels,
166 content_size: Size<Pixels>,
167 pub(crate) layout_engine: TaffyLayoutEngine,
168 pub(crate) root_view: Option<AnyView>,
169 pub(crate) element_id_stack: GlobalElementId,
170 prev_frame_element_states: HashMap<GlobalElementId, AnyBox>,
171 element_states: HashMap<GlobalElementId, AnyBox>,
172 prev_frame_key_matchers: HashMap<GlobalElementId, KeyMatcher>,
173 key_matchers: HashMap<GlobalElementId, KeyMatcher>,
174 z_index_stack: StackingOrder,
175 content_mask_stack: Vec<ContentMask<Pixels>>,
176 element_offset_stack: Vec<Point<Pixels>>,
177 mouse_listeners: HashMap<TypeId, Vec<(StackingOrder, AnyListener)>>,
178 key_dispatch_stack: Vec<KeyDispatchStackFrame>,
179 freeze_key_dispatch_stack: bool,
180 focus_stack: Vec<FocusId>,
181 focus_parents_by_child: HashMap<FocusId, FocusId>,
182 pub(crate) focus_listeners: Vec<AnyFocusListener>,
183 pub(crate) focus_handles: Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>,
184 default_prevented: bool,
185 mouse_position: Point<Pixels>,
186 scale_factor: f32,
187 pub(crate) scene_builder: SceneBuilder,
188 pub(crate) dirty: bool,
189 pub(crate) last_blur: Option<Option<FocusId>>,
190 pub(crate) focus: Option<FocusId>,
191}
192
193impl Window {
194 pub(crate) fn new(
195 handle: AnyWindowHandle,
196 options: WindowOptions,
197 cx: &mut MainThread<AppContext>,
198 ) -> Self {
199 let platform_window = cx.platform().open_window(handle, options);
200 let display_id = platform_window.display().id();
201 let sprite_atlas = platform_window.sprite_atlas();
202 let mouse_position = platform_window.mouse_position();
203 let content_size = platform_window.content_size();
204 let scale_factor = platform_window.scale_factor();
205 platform_window.on_resize(Box::new({
206 let cx = cx.to_async();
207 move |content_size, scale_factor| {
208 cx.update_window(handle, |cx| {
209 cx.window.scale_factor = scale_factor;
210 cx.window.scene_builder = SceneBuilder::new();
211 cx.window.content_size = content_size;
212 cx.window.display_id = cx
213 .window
214 .platform_window
215 .borrow_on_main_thread()
216 .display()
217 .id();
218 cx.window.dirty = true;
219 })
220 .log_err();
221 }
222 }));
223
224 platform_window.on_input({
225 let cx = cx.to_async();
226 Box::new(move |event| {
227 cx.update_window(handle, |cx| cx.dispatch_event(event))
228 .log_err()
229 .unwrap_or(true)
230 })
231 });
232
233 let platform_window = MainThreadOnly::new(Arc::new(platform_window), cx.executor.clone());
234
235 Window {
236 handle,
237 platform_window,
238 display_id,
239 sprite_atlas,
240 rem_size: px(16.),
241 content_size,
242 layout_engine: TaffyLayoutEngine::new(),
243 root_view: None,
244 element_id_stack: GlobalElementId::default(),
245 prev_frame_element_states: HashMap::default(),
246 element_states: HashMap::default(),
247 prev_frame_key_matchers: HashMap::default(),
248 key_matchers: HashMap::default(),
249 z_index_stack: StackingOrder(SmallVec::new()),
250 content_mask_stack: Vec::new(),
251 element_offset_stack: Vec::new(),
252 mouse_listeners: HashMap::default(),
253 key_dispatch_stack: Vec::new(),
254 freeze_key_dispatch_stack: false,
255 focus_stack: Vec::new(),
256 focus_parents_by_child: HashMap::default(),
257 focus_listeners: Vec::new(),
258 focus_handles: Arc::new(RwLock::new(SlotMap::with_key())),
259 default_prevented: true,
260 mouse_position,
261 scale_factor,
262 scene_builder: SceneBuilder::new(),
263 dirty: true,
264 last_blur: None,
265 focus: None,
266 }
267 }
268}
269
270/// When constructing the element tree, we maintain a stack of key dispatch frames until we
271/// find the focused element. We interleave key listeners with dispatch contexts so we can use the
272/// contexts when matching key events against the keymap.
273enum KeyDispatchStackFrame {
274 Listener {
275 event_type: TypeId,
276 listener: AnyKeyListener,
277 },
278 Context(DispatchContext),
279}
280
281/// Indicates which region of the window is visible. Content falling outside of this mask will not be
282/// rendered. Currently, only rectangular content masks are supported, but we give the mask its own type
283/// to leave room to support more complex shapes in the future.
284#[derive(Clone, Debug, Default, PartialEq, Eq)]
285#[repr(C)]
286pub struct ContentMask<P: Clone + Default + Debug> {
287 pub bounds: Bounds<P>,
288}
289
290impl ContentMask<Pixels> {
291 /// Scale the content mask's pixel units by the given scaling factor.
292 pub fn scale(&self, factor: f32) -> ContentMask<ScaledPixels> {
293 ContentMask {
294 bounds: self.bounds.scale(factor),
295 }
296 }
297
298 /// Intersect the content mask with the given content mask.
299 pub fn intersect(&self, other: &Self) -> Self {
300 let bounds = self.bounds.intersect(&other.bounds);
301 ContentMask { bounds }
302 }
303}
304
305/// Provides access to application state in the context of a single window. Derefs
306/// to an `AppContext`, so you can also pass a `WindowContext` to any method that takes
307/// an `AppContext` and call any `AppContext` methods.
308pub struct WindowContext<'a> {
309 pub(crate) app: &'a mut AppContext,
310 pub(crate) window: &'a mut Window,
311}
312
313impl<'a> WindowContext<'a> {
314 pub(crate) fn new(app: &'a mut AppContext, window: &'a mut Window) -> Self {
315 Self { app, window }
316 }
317
318 /// Obtain a handle to the window that belongs to this context.
319 pub fn window_handle(&self) -> AnyWindowHandle {
320 self.window.handle
321 }
322
323 /// Mark the window as dirty, scheduling it to be redrawn on the next frame.
324 pub fn notify(&mut self) {
325 self.window.dirty = true;
326 }
327
328 /// Obtain a new `FocusHandle`, which allows you to track and manipulate the keyboard focus
329 /// for elements rendered within this window.
330 pub fn focus_handle(&mut self) -> FocusHandle {
331 FocusHandle::new(&self.window.focus_handles)
332 }
333
334 /// Obtain the currently focused `FocusHandle`. If no elements are focused, returns `None`.
335 pub fn focused(&self) -> Option<FocusHandle> {
336 self.window
337 .focus
338 .and_then(|id| FocusHandle::for_id(id, &self.window.focus_handles))
339 }
340
341 /// Move focus to the element associated with the given `FocusHandle`.
342 pub fn focus(&mut self, handle: &FocusHandle) {
343 if self.window.last_blur.is_none() {
344 self.window.last_blur = Some(self.window.focus);
345 }
346
347 self.window.focus = Some(handle.id);
348 self.app.push_effect(Effect::FocusChanged {
349 window_handle: self.window.handle,
350 focused: Some(handle.id),
351 });
352 self.notify();
353 }
354
355 /// Remove focus from all elements within this context's window.
356 pub fn blur(&mut self) {
357 if self.window.last_blur.is_none() {
358 self.window.last_blur = Some(self.window.focus);
359 }
360
361 self.window.focus = None;
362 self.app.push_effect(Effect::FocusChanged {
363 window_handle: self.window.handle,
364 focused: None,
365 });
366 self.notify();
367 }
368
369 /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
370 /// that are currently on the stack to be returned to the app.
371 pub fn defer(&mut self, f: impl FnOnce(&mut WindowContext) + 'static + Send) {
372 let window = self.window.handle;
373 self.app.defer(move |cx| {
374 cx.update_window(window, f).ok();
375 });
376 }
377
378 pub fn subscribe<Emitter, E>(
379 &mut self,
380 entity: &E,
381 mut on_event: impl FnMut(E, &Emitter::Event, &mut WindowContext<'_>) + Send + 'static,
382 ) -> Subscription
383 where
384 Emitter: EventEmitter,
385 E: Entity<Emitter>,
386 {
387 let entity_id = entity.entity_id();
388 let entity = entity.downgrade();
389 let window_handle = self.window.handle;
390 self.app.event_listeners.insert(
391 entity_id,
392 Box::new(move |event, cx| {
393 cx.update_window(window_handle, |cx| {
394 if let Some(handle) = E::upgrade_from(&entity) {
395 let event = event.downcast_ref().expect("invalid event type");
396 on_event(handle, event, cx);
397 true
398 } else {
399 false
400 }
401 })
402 .unwrap_or(false)
403 }),
404 )
405 }
406
407 /// Schedule the given closure to be run on the main thread. It will be invoked with
408 /// a `MainThread<WindowContext>`, which provides access to platform-specific functionality
409 /// of the window.
410 pub fn run_on_main<R>(
411 &mut self,
412 f: impl FnOnce(&mut MainThread<WindowContext<'_>>) -> R + Send + 'static,
413 ) -> Task<Result<R>>
414 where
415 R: Send + 'static,
416 {
417 if self.executor.is_main_thread() {
418 Task::ready(Ok(f(unsafe {
419 mem::transmute::<&mut Self, &mut MainThread<Self>>(self)
420 })))
421 } else {
422 let handle = self.window.handle;
423 self.app.run_on_main(move |cx| cx.update_window(handle, f))
424 }
425 }
426
427 /// Create an `AsyncWindowContext`, which has a static lifetime and can be held across
428 /// await points in async code.
429 pub fn to_async(&self) -> AsyncWindowContext {
430 AsyncWindowContext::new(self.app.to_async(), self.window.handle)
431 }
432
433 /// Schedule the given closure to be run directly after the current frame is rendered.
434 pub fn on_next_frame(&mut self, f: impl FnOnce(&mut WindowContext) + Send + 'static) {
435 let f = Box::new(f);
436 let display_id = self.window.display_id;
437 self.run_on_main(move |cx| {
438 if let Some(callbacks) = cx.next_frame_callbacks.get_mut(&display_id) {
439 callbacks.push(f);
440 // If there was already a callback, it means that we already scheduled a frame.
441 if callbacks.len() > 1 {
442 return;
443 }
444 } else {
445 let async_cx = cx.to_async();
446 cx.next_frame_callbacks.insert(display_id, vec![f]);
447 cx.platform().set_display_link_output_callback(
448 display_id,
449 Box::new(move |_current_time, _output_time| {
450 let _ = async_cx.update(|cx| {
451 let callbacks = cx
452 .next_frame_callbacks
453 .get_mut(&display_id)
454 .unwrap()
455 .drain(..)
456 .collect::<Vec<_>>();
457 for callback in callbacks {
458 callback(cx);
459 }
460
461 cx.run_on_main(move |cx| {
462 if cx.next_frame_callbacks.get(&display_id).unwrap().is_empty() {
463 cx.platform().stop_display_link(display_id);
464 }
465 })
466 .detach();
467 });
468 }),
469 );
470 }
471
472 cx.platform().start_display_link(display_id);
473 })
474 .detach();
475 }
476
477 /// Spawn the future returned by the given closure on the application thread pool.
478 /// The closure is provided a handle to the current window and an `AsyncWindowContext` for
479 /// use within your future.
480 pub fn spawn<Fut, R>(
481 &mut self,
482 f: impl FnOnce(AnyWindowHandle, AsyncWindowContext) -> Fut + Send + 'static,
483 ) -> Task<R>
484 where
485 R: Send + 'static,
486 Fut: Future<Output = R> + Send + 'static,
487 {
488 let window = self.window.handle;
489 self.app.spawn(move |app| {
490 let cx = AsyncWindowContext::new(app, window);
491 let future = f(window, cx);
492 async move { future.await }
493 })
494 }
495
496 /// Update the global of the given type. The given closure is given simultaneous mutable
497 /// access both to the global and the context.
498 pub fn update_global<G, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R
499 where
500 G: 'static,
501 {
502 let mut global = self.app.lease_global::<G>();
503 let result = f(&mut global, self);
504 self.app.end_global_lease(global);
505 result
506 }
507
508 /// Add a node to the layout tree for the current frame. Takes the `Style` of the element for which
509 /// layout is being requested, along with the layout ids of any children. This method is called during
510 /// calls to the `Element::layout` trait method and enables any element to participate in layout.
511 pub fn request_layout(
512 &mut self,
513 style: &Style,
514 children: impl IntoIterator<Item = LayoutId>,
515 ) -> LayoutId {
516 self.app.layout_id_buffer.clear();
517 self.app.layout_id_buffer.extend(children.into_iter());
518 let rem_size = self.rem_size();
519
520 self.window
521 .layout_engine
522 .request_layout(style, rem_size, &self.app.layout_id_buffer)
523 }
524
525 /// Add a node to the layout tree for the current frame. Instead of taking a `Style` and children,
526 /// this variant takes a function that is invoked during layout so you can use arbitrary logic to
527 /// determine the element's size. One place this is used internally is when measuring text.
528 ///
529 /// The given closure is invoked at layout time with the known dimensions and available space and
530 /// returns a `Size`.
531 pub fn request_measured_layout<
532 F: Fn(Size<Option<Pixels>>, Size<AvailableSpace>) -> Size<Pixels> + Send + Sync + 'static,
533 >(
534 &mut self,
535 style: Style,
536 rem_size: Pixels,
537 measure: F,
538 ) -> LayoutId {
539 self.window
540 .layout_engine
541 .request_measured_layout(style, rem_size, measure)
542 }
543
544 /// Obtain the bounds computed for the given LayoutId relative to the window. This method should not
545 /// be invoked until the paint phase begins, and will usually be invoked by GPUI itself automatically
546 /// in order to pass your element its `Bounds` automatically.
547 pub fn layout_bounds(&mut self, layout_id: LayoutId) -> Bounds<Pixels> {
548 let mut bounds = self
549 .window
550 .layout_engine
551 .layout_bounds(layout_id)
552 .map(Into::into);
553 bounds.origin += self.element_offset();
554 bounds
555 }
556
557 /// The scale factor of the display associated with the window. For example, it could
558 /// return 2.0 for a "retina" display, indicating that each logical pixel should actually
559 /// be rendered as two pixels on screen.
560 pub fn scale_factor(&self) -> f32 {
561 self.window.scale_factor
562 }
563
564 /// The size of an em for the base font of the application. Adjusting this value allows the
565 /// UI to scale, just like zooming a web page.
566 pub fn rem_size(&self) -> Pixels {
567 self.window.rem_size
568 }
569
570 /// The line height associated with the current text style.
571 pub fn line_height(&self) -> Pixels {
572 let rem_size = self.rem_size();
573 let text_style = self.text_style();
574 text_style
575 .line_height
576 .to_pixels(text_style.font_size.into(), rem_size)
577 }
578
579 /// Call to prevent the default action of an event. Currently only used to prevent
580 /// parent elements from becoming focused on mouse down.
581 pub fn prevent_default(&mut self) {
582 self.window.default_prevented = true;
583 }
584
585 /// Obtain whether default has been prevented for the event currently being dispatched.
586 pub fn default_prevented(&self) -> bool {
587 self.window.default_prevented
588 }
589
590 /// Register a mouse event listener on the window for the current frame. The type of event
591 /// is determined by the first parameter of the given listener. When the next frame is rendered
592 /// the listener will be cleared.
593 ///
594 /// This is a fairly low-level method, so prefer using event handlers on elements unless you have
595 /// a specific need to register a global listener.
596 pub fn on_mouse_event<Event: 'static>(
597 &mut self,
598 handler: impl Fn(&Event, DispatchPhase, &mut WindowContext) + Send + 'static,
599 ) {
600 let order = self.window.z_index_stack.clone();
601 self.window
602 .mouse_listeners
603 .entry(TypeId::of::<Event>())
604 .or_default()
605 .push((
606 order,
607 Box::new(move |event: &dyn Any, phase, cx| {
608 handler(event.downcast_ref().unwrap(), phase, cx)
609 }),
610 ))
611 }
612
613 /// The position of the mouse relative to the window.
614 pub fn mouse_position(&self) -> Point<Pixels> {
615 self.window.mouse_position
616 }
617
618 /// Called during painting to invoke the given closure in a new stacking context. The given
619 /// z-index is interpreted relative to the previous call to `stack`.
620 pub fn stack<R>(&mut self, z_index: u32, f: impl FnOnce(&mut Self) -> R) -> R {
621 self.window.z_index_stack.push(z_index);
622 let result = f(self);
623 self.window.z_index_stack.pop();
624 result
625 }
626
627 /// Paint one or more drop shadows into the scene for the current frame at the current z-index.
628 pub fn paint_shadows(
629 &mut self,
630 bounds: Bounds<Pixels>,
631 corner_radii: Corners<Pixels>,
632 shadows: &[BoxShadow],
633 ) {
634 let scale_factor = self.scale_factor();
635 let content_mask = self.content_mask();
636 let window = &mut *self.window;
637 for shadow in shadows {
638 let mut shadow_bounds = bounds;
639 shadow_bounds.origin += shadow.offset;
640 shadow_bounds.dilate(shadow.spread_radius);
641 window.scene_builder.insert(
642 &window.z_index_stack,
643 Shadow {
644 order: 0,
645 bounds: shadow_bounds.scale(scale_factor),
646 content_mask: content_mask.scale(scale_factor),
647 corner_radii: corner_radii.scale(scale_factor),
648 color: shadow.color,
649 blur_radius: shadow.blur_radius.scale(scale_factor),
650 },
651 );
652 }
653 }
654
655 /// Paint one or more quads into the scene for the current frame at the current stacking context.
656 /// Quads are colored rectangular regions with an optional background, border, and corner radius.
657 pub fn paint_quad(
658 &mut self,
659 bounds: Bounds<Pixels>,
660 corner_radii: Corners<Pixels>,
661 background: impl Into<Hsla>,
662 border_widths: Edges<Pixels>,
663 border_color: impl Into<Hsla>,
664 ) {
665 let scale_factor = self.scale_factor();
666 let content_mask = self.content_mask();
667
668 let window = &mut *self.window;
669 window.scene_builder.insert(
670 &window.z_index_stack,
671 Quad {
672 order: 0,
673 bounds: bounds.scale(scale_factor),
674 content_mask: content_mask.scale(scale_factor),
675 background: background.into(),
676 border_color: border_color.into(),
677 corner_radii: corner_radii.scale(scale_factor),
678 border_widths: border_widths.scale(scale_factor),
679 },
680 );
681 }
682
683 /// Paint the given `Path` into the scene for the current frame at the current z-index.
684 pub fn paint_path(&mut self, mut path: Path<Pixels>, color: impl Into<Hsla>) {
685 let scale_factor = self.scale_factor();
686 let content_mask = self.content_mask();
687 path.content_mask = content_mask;
688 path.color = color.into();
689 let window = &mut *self.window;
690 window
691 .scene_builder
692 .insert(&window.z_index_stack, path.scale(scale_factor));
693 }
694
695 /// Paint an underline into the scene for the current frame at the current z-index.
696 pub fn paint_underline(
697 &mut self,
698 origin: Point<Pixels>,
699 width: Pixels,
700 style: &UnderlineStyle,
701 ) -> Result<()> {
702 let scale_factor = self.scale_factor();
703 let height = if style.wavy {
704 style.thickness * 3.
705 } else {
706 style.thickness
707 };
708 let bounds = Bounds {
709 origin,
710 size: size(width, height),
711 };
712 let content_mask = self.content_mask();
713 let window = &mut *self.window;
714 window.scene_builder.insert(
715 &window.z_index_stack,
716 Underline {
717 order: 0,
718 bounds: bounds.scale(scale_factor),
719 content_mask: content_mask.scale(scale_factor),
720 thickness: style.thickness.scale(scale_factor),
721 color: style.color.unwrap_or_default(),
722 wavy: style.wavy,
723 },
724 );
725 Ok(())
726 }
727
728 /// Paint a monochrome (non-emoji) glyph into the scene for the current frame at the current z-index.
729 pub fn paint_glyph(
730 &mut self,
731 origin: Point<Pixels>,
732 font_id: FontId,
733 glyph_id: GlyphId,
734 font_size: Pixels,
735 color: Hsla,
736 ) -> Result<()> {
737 let scale_factor = self.scale_factor();
738 let glyph_origin = origin.scale(scale_factor);
739 let subpixel_variant = Point {
740 x: (glyph_origin.x.0.fract() * SUBPIXEL_VARIANTS as f32).floor() as u8,
741 y: (glyph_origin.y.0.fract() * SUBPIXEL_VARIANTS as f32).floor() as u8,
742 };
743 let params = RenderGlyphParams {
744 font_id,
745 glyph_id,
746 font_size,
747 subpixel_variant,
748 scale_factor,
749 is_emoji: false,
750 };
751
752 let raster_bounds = self.text_system().raster_bounds(¶ms)?;
753 if !raster_bounds.is_zero() {
754 let tile =
755 self.window
756 .sprite_atlas
757 .get_or_insert_with(¶ms.clone().into(), &mut || {
758 let (size, bytes) = self.text_system().rasterize_glyph(¶ms)?;
759 Ok((size, Cow::Owned(bytes)))
760 })?;
761 let bounds = Bounds {
762 origin: glyph_origin.map(|px| px.floor()) + raster_bounds.origin.map(Into::into),
763 size: tile.bounds.size.map(Into::into),
764 };
765 let content_mask = self.content_mask().scale(scale_factor);
766 let window = &mut *self.window;
767 window.scene_builder.insert(
768 &window.z_index_stack,
769 MonochromeSprite {
770 order: 0,
771 bounds,
772 content_mask,
773 color,
774 tile,
775 },
776 );
777 }
778 Ok(())
779 }
780
781 /// Paint an emoji glyph into the scene for the current frame at the current z-index.
782 pub fn paint_emoji(
783 &mut self,
784 origin: Point<Pixels>,
785 font_id: FontId,
786 glyph_id: GlyphId,
787 font_size: Pixels,
788 ) -> Result<()> {
789 let scale_factor = self.scale_factor();
790 let glyph_origin = origin.scale(scale_factor);
791 let params = RenderGlyphParams {
792 font_id,
793 glyph_id,
794 font_size,
795 // We don't render emojis with subpixel variants.
796 subpixel_variant: Default::default(),
797 scale_factor,
798 is_emoji: true,
799 };
800
801 let raster_bounds = self.text_system().raster_bounds(¶ms)?;
802 if !raster_bounds.is_zero() {
803 let tile =
804 self.window
805 .sprite_atlas
806 .get_or_insert_with(¶ms.clone().into(), &mut || {
807 let (size, bytes) = self.text_system().rasterize_glyph(¶ms)?;
808 Ok((size, Cow::Owned(bytes)))
809 })?;
810 let bounds = Bounds {
811 origin: glyph_origin.map(|px| px.floor()) + raster_bounds.origin.map(Into::into),
812 size: tile.bounds.size.map(Into::into),
813 };
814 let content_mask = self.content_mask().scale(scale_factor);
815 let window = &mut *self.window;
816
817 window.scene_builder.insert(
818 &window.z_index_stack,
819 PolychromeSprite {
820 order: 0,
821 bounds,
822 corner_radii: Default::default(),
823 content_mask,
824 tile,
825 grayscale: false,
826 },
827 );
828 }
829 Ok(())
830 }
831
832 /// Paint a monochrome SVG into the scene for the current frame at the current stacking context.
833 pub fn paint_svg(
834 &mut self,
835 bounds: Bounds<Pixels>,
836 path: SharedString,
837 color: Hsla,
838 ) -> Result<()> {
839 let scale_factor = self.scale_factor();
840 let bounds = bounds.scale(scale_factor);
841 // Render the SVG at twice the size to get a higher quality result.
842 let params = RenderSvgParams {
843 path,
844 size: bounds
845 .size
846 .map(|pixels| DevicePixels::from((pixels.0 * 2.).ceil() as i32)),
847 };
848
849 let tile =
850 self.window
851 .sprite_atlas
852 .get_or_insert_with(¶ms.clone().into(), &mut || {
853 let bytes = self.svg_renderer.render(¶ms)?;
854 Ok((params.size, Cow::Owned(bytes)))
855 })?;
856 let content_mask = self.content_mask().scale(scale_factor);
857
858 let window = &mut *self.window;
859 window.scene_builder.insert(
860 &window.z_index_stack,
861 MonochromeSprite {
862 order: 0,
863 bounds,
864 content_mask,
865 color,
866 tile,
867 },
868 );
869
870 Ok(())
871 }
872
873 /// Paint an image into the scene for the current frame at the current z-index.
874 pub fn paint_image(
875 &mut self,
876 bounds: Bounds<Pixels>,
877 corner_radii: Corners<Pixels>,
878 data: Arc<ImageData>,
879 grayscale: bool,
880 ) -> Result<()> {
881 let scale_factor = self.scale_factor();
882 let bounds = bounds.scale(scale_factor);
883 let params = RenderImageParams { image_id: data.id };
884
885 let tile = self
886 .window
887 .sprite_atlas
888 .get_or_insert_with(¶ms.clone().into(), &mut || {
889 Ok((data.size(), Cow::Borrowed(data.as_bytes())))
890 })?;
891 let content_mask = self.content_mask().scale(scale_factor);
892 let corner_radii = corner_radii.scale(scale_factor);
893
894 let window = &mut *self.window;
895 window.scene_builder.insert(
896 &window.z_index_stack,
897 PolychromeSprite {
898 order: 0,
899 bounds,
900 content_mask,
901 corner_radii,
902 tile,
903 grayscale,
904 },
905 );
906 Ok(())
907 }
908
909 /// Draw pixels to the display for this window based on the contents of its scene.
910 pub(crate) fn draw(&mut self) {
911 let root_view = self.window.root_view.take().unwrap();
912
913 self.start_frame();
914
915 self.stack(0, |cx| {
916 let available_space = cx.window.content_size.map(Into::into);
917 root_view.draw(available_space, cx);
918 });
919
920 if let Some(active_drag) = self.app.active_drag.take() {
921 self.stack(1, |cx| {
922 let offset = cx.mouse_position() - active_drag.cursor_offset;
923 cx.with_element_offset(Some(offset), |cx| {
924 let available_space =
925 size(AvailableSpace::MinContent, AvailableSpace::MinContent);
926 active_drag.view.draw(available_space, cx);
927 cx.active_drag = Some(active_drag);
928 });
929 });
930 }
931
932 self.window.root_view = Some(root_view);
933 let scene = self.window.scene_builder.build();
934
935 self.run_on_main(|cx| {
936 cx.window
937 .platform_window
938 .borrow_on_main_thread()
939 .draw(scene);
940 cx.window.dirty = false;
941 })
942 .detach();
943 }
944
945 fn start_frame(&mut self) {
946 self.text_system().start_frame();
947
948 let window = &mut *self.window;
949
950 // Move the current frame element states to the previous frame.
951 // The new empty element states map will be populated for any element states we
952 // reference during the upcoming frame.
953 mem::swap(
954 &mut window.element_states,
955 &mut window.prev_frame_element_states,
956 );
957 window.element_states.clear();
958
959 // Make the current key matchers the previous, and then clear the current.
960 // An empty key matcher map will be created for every identified element in the
961 // upcoming frame.
962 mem::swap(
963 &mut window.key_matchers,
964 &mut window.prev_frame_key_matchers,
965 );
966 window.key_matchers.clear();
967
968 // Clear mouse event listeners, because elements add new element listeners
969 // when the upcoming frame is painted.
970 window.mouse_listeners.values_mut().for_each(Vec::clear);
971
972 // Clear focus state, because we determine what is focused when the new elements
973 // in the upcoming frame are initialized.
974 window.focus_listeners.clear();
975 window.key_dispatch_stack.clear();
976 window.focus_parents_by_child.clear();
977 window.freeze_key_dispatch_stack = false;
978 }
979
980 /// Dispatch a mouse or keyboard event on the window.
981 fn dispatch_event(&mut self, event: InputEvent) -> bool {
982 let event = match event {
983 // Track the mouse position with our own state, since accessing the platform
984 // API for the mouse position can only occur on the main thread.
985 InputEvent::MouseMove(mouse_move) => {
986 self.window.mouse_position = mouse_move.position;
987 InputEvent::MouseMove(mouse_move)
988 }
989 // Translate dragging and dropping of external files from the operating system
990 // to internal drag and drop events.
991 InputEvent::FileDrop(file_drop) => match file_drop {
992 FileDropEvent::Entered { position, files } => {
993 self.window.mouse_position = position;
994 if self.active_drag.is_none() {
995 self.active_drag = Some(AnyDrag {
996 view: self.build_view(|_| files).into(),
997 cursor_offset: position,
998 });
999 }
1000 InputEvent::MouseDown(MouseDownEvent {
1001 position,
1002 button: MouseButton::Left,
1003 click_count: 1,
1004 modifiers: Modifiers::default(),
1005 })
1006 }
1007 FileDropEvent::Pending { position } => {
1008 self.window.mouse_position = position;
1009 InputEvent::MouseMove(MouseMoveEvent {
1010 position,
1011 pressed_button: Some(MouseButton::Left),
1012 modifiers: Modifiers::default(),
1013 })
1014 }
1015 FileDropEvent::Submit { position } => {
1016 self.window.mouse_position = position;
1017 InputEvent::MouseUp(MouseUpEvent {
1018 button: MouseButton::Left,
1019 position,
1020 modifiers: Modifiers::default(),
1021 click_count: 1,
1022 })
1023 }
1024 FileDropEvent::Exited => InputEvent::MouseUp(MouseUpEvent {
1025 button: MouseButton::Left,
1026 position: Point::default(),
1027 modifiers: Modifiers::default(),
1028 click_count: 1,
1029 }),
1030 },
1031 _ => event,
1032 };
1033
1034 if let Some(any_mouse_event) = event.mouse_event() {
1035 // Handlers may set this to false by calling `stop_propagation`
1036 self.app.propagate_event = true;
1037 self.window.default_prevented = false;
1038
1039 if let Some(mut handlers) = self
1040 .window
1041 .mouse_listeners
1042 .remove(&any_mouse_event.type_id())
1043 {
1044 // Because handlers may add other handlers, we sort every time.
1045 handlers.sort_by(|(a, _), (b, _)| a.cmp(b));
1046
1047 // Capture phase, events bubble from back to front. Handlers for this phase are used for
1048 // special purposes, such as detecting events outside of a given Bounds.
1049 for (_, handler) in &handlers {
1050 handler(any_mouse_event, DispatchPhase::Capture, self);
1051 if !self.app.propagate_event {
1052 break;
1053 }
1054 }
1055
1056 // Bubble phase, where most normal handlers do their work.
1057 if self.app.propagate_event {
1058 for (_, handler) in handlers.iter().rev() {
1059 handler(any_mouse_event, DispatchPhase::Bubble, self);
1060 if !self.app.propagate_event {
1061 break;
1062 }
1063 }
1064 }
1065
1066 if self.app.propagate_event
1067 && any_mouse_event.downcast_ref::<MouseUpEvent>().is_some()
1068 {
1069 self.active_drag = None;
1070 }
1071
1072 // Just in case any handlers added new handlers, which is weird, but possible.
1073 handlers.extend(
1074 self.window
1075 .mouse_listeners
1076 .get_mut(&any_mouse_event.type_id())
1077 .into_iter()
1078 .flat_map(|handlers| handlers.drain(..)),
1079 );
1080 self.window
1081 .mouse_listeners
1082 .insert(any_mouse_event.type_id(), handlers);
1083 }
1084 } else if let Some(any_key_event) = event.keyboard_event() {
1085 let key_dispatch_stack = mem::take(&mut self.window.key_dispatch_stack);
1086 let key_event_type = any_key_event.type_id();
1087 let mut context_stack = SmallVec::<[&DispatchContext; 16]>::new();
1088
1089 for (ix, frame) in key_dispatch_stack.iter().enumerate() {
1090 match frame {
1091 KeyDispatchStackFrame::Listener {
1092 event_type,
1093 listener,
1094 } => {
1095 if key_event_type == *event_type {
1096 if let Some(action) = listener(
1097 any_key_event,
1098 &context_stack,
1099 DispatchPhase::Capture,
1100 self,
1101 ) {
1102 self.dispatch_action(action, &key_dispatch_stack[..ix]);
1103 }
1104 if !self.app.propagate_event {
1105 break;
1106 }
1107 }
1108 }
1109 KeyDispatchStackFrame::Context(context) => {
1110 context_stack.push(&context);
1111 }
1112 }
1113 }
1114
1115 if self.app.propagate_event {
1116 for (ix, frame) in key_dispatch_stack.iter().enumerate().rev() {
1117 match frame {
1118 KeyDispatchStackFrame::Listener {
1119 event_type,
1120 listener,
1121 } => {
1122 if key_event_type == *event_type {
1123 if let Some(action) = listener(
1124 any_key_event,
1125 &context_stack,
1126 DispatchPhase::Bubble,
1127 self,
1128 ) {
1129 self.dispatch_action(action, &key_dispatch_stack[..ix]);
1130 }
1131
1132 if !self.app.propagate_event {
1133 break;
1134 }
1135 }
1136 }
1137 KeyDispatchStackFrame::Context(_) => {
1138 context_stack.pop();
1139 }
1140 }
1141 }
1142 }
1143
1144 drop(context_stack);
1145 self.window.key_dispatch_stack = key_dispatch_stack;
1146 }
1147
1148 true
1149 }
1150
1151 /// Attempt to map a keystroke to an action based on the keymap.
1152 pub fn match_keystroke(
1153 &mut self,
1154 element_id: &GlobalElementId,
1155 keystroke: &Keystroke,
1156 context_stack: &[&DispatchContext],
1157 ) -> KeyMatch {
1158 let key_match = self
1159 .window
1160 .key_matchers
1161 .get_mut(element_id)
1162 .unwrap()
1163 .match_keystroke(keystroke, context_stack);
1164
1165 if key_match.is_some() {
1166 for matcher in self.window.key_matchers.values_mut() {
1167 matcher.clear_pending();
1168 }
1169 }
1170
1171 key_match
1172 }
1173
1174 /// Register the given handler to be invoked whenever the global of the given type
1175 /// is updated.
1176 pub fn observe_global<G: 'static>(
1177 &mut self,
1178 f: impl Fn(&mut WindowContext<'_>) + Send + 'static,
1179 ) -> Subscription {
1180 let window_handle = self.window.handle;
1181 self.global_observers.insert(
1182 TypeId::of::<G>(),
1183 Box::new(move |cx| cx.update_window(window_handle, |cx| f(cx)).is_ok()),
1184 )
1185 }
1186
1187 fn dispatch_action(
1188 &mut self,
1189 action: Box<dyn Action>,
1190 dispatch_stack: &[KeyDispatchStackFrame],
1191 ) {
1192 let action_type = action.as_any().type_id();
1193
1194 if let Some(mut global_listeners) = self.app.global_action_listeners.remove(&action_type) {
1195 for listener in &global_listeners {
1196 listener(action.as_ref(), DispatchPhase::Capture, self);
1197 if !self.app.propagate_event {
1198 break;
1199 }
1200 }
1201 global_listeners.extend(
1202 self.global_action_listeners
1203 .remove(&action_type)
1204 .unwrap_or_default(),
1205 );
1206 self.global_action_listeners
1207 .insert(action_type, global_listeners);
1208 }
1209
1210 if self.app.propagate_event {
1211 for stack_frame in dispatch_stack {
1212 if let KeyDispatchStackFrame::Listener {
1213 event_type,
1214 listener,
1215 } = stack_frame
1216 {
1217 if action_type == *event_type {
1218 listener(action.as_any(), &[], DispatchPhase::Capture, self);
1219 if !self.app.propagate_event {
1220 break;
1221 }
1222 }
1223 }
1224 }
1225 }
1226
1227 if self.app.propagate_event {
1228 for stack_frame in dispatch_stack.iter().rev() {
1229 if let KeyDispatchStackFrame::Listener {
1230 event_type,
1231 listener,
1232 } = stack_frame
1233 {
1234 if action_type == *event_type {
1235 listener(action.as_any(), &[], DispatchPhase::Bubble, self);
1236 if !self.app.propagate_event {
1237 break;
1238 }
1239 }
1240 }
1241 }
1242 }
1243
1244 if self.app.propagate_event {
1245 if let Some(mut global_listeners) =
1246 self.app.global_action_listeners.remove(&action_type)
1247 {
1248 for listener in global_listeners.iter().rev() {
1249 listener(action.as_ref(), DispatchPhase::Bubble, self);
1250 if !self.app.propagate_event {
1251 break;
1252 }
1253 }
1254 global_listeners.extend(
1255 self.global_action_listeners
1256 .remove(&action_type)
1257 .unwrap_or_default(),
1258 );
1259 self.global_action_listeners
1260 .insert(action_type, global_listeners);
1261 }
1262 }
1263 }
1264}
1265
1266impl Context for WindowContext<'_> {
1267 type ModelContext<'a, T> = ModelContext<'a, T>;
1268 type Result<T> = T;
1269
1270 fn build_model<T>(
1271 &mut self,
1272 build_model: impl FnOnce(&mut Self::ModelContext<'_, T>) -> T,
1273 ) -> Model<T>
1274 where
1275 T: 'static + Send,
1276 {
1277 let slot = self.app.entities.reserve();
1278 let model = build_model(&mut ModelContext::new(&mut *self.app, slot.downgrade()));
1279 self.entities.insert(slot, model)
1280 }
1281
1282 fn update_model<T: 'static, R>(
1283 &mut self,
1284 model: &Model<T>,
1285 update: impl FnOnce(&mut T, &mut Self::ModelContext<'_, T>) -> R,
1286 ) -> R {
1287 let mut entity = self.entities.lease(model);
1288 let result = update(
1289 &mut *entity,
1290 &mut ModelContext::new(&mut *self.app, model.downgrade()),
1291 );
1292 self.entities.end_lease(entity);
1293 result
1294 }
1295}
1296
1297impl VisualContext for WindowContext<'_> {
1298 type ViewContext<'a, V: 'static> = ViewContext<'a, V>;
1299
1300 fn build_view<V>(
1301 &mut self,
1302 build_view_state: impl FnOnce(&mut Self::ViewContext<'_, V>) -> V,
1303 ) -> Self::Result<View<V>>
1304 where
1305 V: 'static + Send,
1306 {
1307 let slot = self.app.entities.reserve();
1308 let view = View {
1309 model: slot.clone(),
1310 };
1311 let mut cx = ViewContext::new(&mut *self.app, &mut *self.window, &view);
1312 let entity = build_view_state(&mut cx);
1313 self.entities.insert(slot, entity);
1314 view
1315 }
1316
1317 /// Update the given view. Prefer calling `View::update` instead, which calls this method.
1318 fn update_view<T: 'static, R>(
1319 &mut self,
1320 view: &View<T>,
1321 update: impl FnOnce(&mut T, &mut Self::ViewContext<'_, T>) -> R,
1322 ) -> Self::Result<R> {
1323 let mut lease = self.app.entities.lease(&view.model);
1324 let mut cx = ViewContext::new(&mut *self.app, &mut *self.window, &view);
1325 let result = update(&mut *lease, &mut cx);
1326 cx.app.entities.end_lease(lease);
1327 result
1328 }
1329}
1330
1331impl<'a> std::ops::Deref for WindowContext<'a> {
1332 type Target = AppContext;
1333
1334 fn deref(&self) -> &Self::Target {
1335 &self.app
1336 }
1337}
1338
1339impl<'a> std::ops::DerefMut for WindowContext<'a> {
1340 fn deref_mut(&mut self) -> &mut Self::Target {
1341 &mut self.app
1342 }
1343}
1344
1345impl<'a> Borrow<AppContext> for WindowContext<'a> {
1346 fn borrow(&self) -> &AppContext {
1347 &self.app
1348 }
1349}
1350
1351impl<'a> BorrowMut<AppContext> for WindowContext<'a> {
1352 fn borrow_mut(&mut self) -> &mut AppContext {
1353 &mut self.app
1354 }
1355}
1356
1357pub trait BorrowWindow: BorrowMut<Window> + BorrowMut<AppContext> {
1358 fn app_mut(&mut self) -> &mut AppContext {
1359 self.borrow_mut()
1360 }
1361
1362 fn window(&self) -> &Window {
1363 self.borrow()
1364 }
1365
1366 fn window_mut(&mut self) -> &mut Window {
1367 self.borrow_mut()
1368 }
1369
1370 /// Pushes the given element id onto the global stack and invokes the given closure
1371 /// with a `GlobalElementId`, which disambiguates the given id in the context of its ancestor
1372 /// ids. Because elements are discarded and recreated on each frame, the `GlobalElementId` is
1373 /// used to associate state with identified elements across separate frames.
1374 fn with_element_id<R>(
1375 &mut self,
1376 id: impl Into<ElementId>,
1377 f: impl FnOnce(GlobalElementId, &mut Self) -> R,
1378 ) -> R {
1379 let keymap = self.app_mut().keymap.clone();
1380 let window = self.window_mut();
1381 window.element_id_stack.push(id.into());
1382 let global_id = window.element_id_stack.clone();
1383
1384 if window.key_matchers.get(&global_id).is_none() {
1385 window.key_matchers.insert(
1386 global_id.clone(),
1387 window
1388 .prev_frame_key_matchers
1389 .remove(&global_id)
1390 .unwrap_or_else(|| KeyMatcher::new(keymap)),
1391 );
1392 }
1393
1394 let result = f(global_id, self);
1395 let window: &mut Window = self.borrow_mut();
1396 window.element_id_stack.pop();
1397 result
1398 }
1399
1400 /// Invoke the given function with the given content mask after intersecting it
1401 /// with the current mask.
1402 fn with_content_mask<R>(
1403 &mut self,
1404 mask: ContentMask<Pixels>,
1405 f: impl FnOnce(&mut Self) -> R,
1406 ) -> R {
1407 let mask = mask.intersect(&self.content_mask());
1408 self.window_mut().content_mask_stack.push(mask);
1409 let result = f(self);
1410 self.window_mut().content_mask_stack.pop();
1411 result
1412 }
1413
1414 /// Update the global element offset based on the given offset. This is used to implement
1415 /// scrolling and position drag handles.
1416 fn with_element_offset<R>(
1417 &mut self,
1418 offset: Option<Point<Pixels>>,
1419 f: impl FnOnce(&mut Self) -> R,
1420 ) -> R {
1421 let Some(offset) = offset else {
1422 return f(self);
1423 };
1424
1425 let offset = self.element_offset() + offset;
1426 self.window_mut().element_offset_stack.push(offset);
1427 let result = f(self);
1428 self.window_mut().element_offset_stack.pop();
1429 result
1430 }
1431
1432 /// Obtain the current element offset.
1433 fn element_offset(&self) -> Point<Pixels> {
1434 self.window()
1435 .element_offset_stack
1436 .last()
1437 .copied()
1438 .unwrap_or_default()
1439 }
1440
1441 /// Update or intialize state for an element with the given id that lives across multiple
1442 /// frames. If an element with this id existed in the previous frame, its state will be passed
1443 /// to the given closure. The state returned by the closure will be stored so it can be referenced
1444 /// when drawing the next frame.
1445 fn with_element_state<S, R>(
1446 &mut self,
1447 id: ElementId,
1448 f: impl FnOnce(Option<S>, &mut Self) -> (R, S),
1449 ) -> R
1450 where
1451 S: 'static + Send,
1452 {
1453 self.with_element_id(id, |global_id, cx| {
1454 if let Some(any) = cx
1455 .window_mut()
1456 .element_states
1457 .remove(&global_id)
1458 .or_else(|| cx.window_mut().prev_frame_element_states.remove(&global_id))
1459 {
1460 // Using the extra inner option to avoid needing to reallocate a new box.
1461 let mut state_box = any
1462 .downcast::<Option<S>>()
1463 .expect("invalid element state type for id");
1464 let state = state_box
1465 .take()
1466 .expect("element state is already on the stack");
1467 let (result, state) = f(Some(state), cx);
1468 state_box.replace(state);
1469 cx.window_mut().element_states.insert(global_id, state_box);
1470 result
1471 } else {
1472 let (result, state) = f(None, cx);
1473 cx.window_mut()
1474 .element_states
1475 .insert(global_id, Box::new(Some(state)));
1476 result
1477 }
1478 })
1479 }
1480
1481 /// Like `with_element_state`, but for situations where the element_id is optional. If the
1482 /// id is `None`, no state will be retrieved or stored.
1483 fn with_optional_element_state<S, R>(
1484 &mut self,
1485 element_id: Option<ElementId>,
1486 f: impl FnOnce(Option<S>, &mut Self) -> (R, S),
1487 ) -> R
1488 where
1489 S: 'static + Send,
1490 {
1491 if let Some(element_id) = element_id {
1492 self.with_element_state(element_id, f)
1493 } else {
1494 f(None, self).0
1495 }
1496 }
1497
1498 /// Obtain the current content mask.
1499 fn content_mask(&self) -> ContentMask<Pixels> {
1500 self.window()
1501 .content_mask_stack
1502 .last()
1503 .cloned()
1504 .unwrap_or_else(|| ContentMask {
1505 bounds: Bounds {
1506 origin: Point::default(),
1507 size: self.window().content_size,
1508 },
1509 })
1510 }
1511
1512 /// The size of an em for the base font of the application. Adjusting this value allows the
1513 /// UI to scale, just like zooming a web page.
1514 fn rem_size(&self) -> Pixels {
1515 self.window().rem_size
1516 }
1517}
1518
1519impl Borrow<Window> for WindowContext<'_> {
1520 fn borrow(&self) -> &Window {
1521 &self.window
1522 }
1523}
1524
1525impl BorrowMut<Window> for WindowContext<'_> {
1526 fn borrow_mut(&mut self) -> &mut Window {
1527 &mut self.window
1528 }
1529}
1530
1531impl<T> BorrowWindow for T where T: BorrowMut<AppContext> + BorrowMut<Window> {}
1532
1533pub struct ViewContext<'a, V> {
1534 window_cx: WindowContext<'a>,
1535 view: &'a View<V>,
1536}
1537
1538impl<V> Borrow<AppContext> for ViewContext<'_, V> {
1539 fn borrow(&self) -> &AppContext {
1540 &*self.window_cx.app
1541 }
1542}
1543
1544impl<V> BorrowMut<AppContext> for ViewContext<'_, V> {
1545 fn borrow_mut(&mut self) -> &mut AppContext {
1546 &mut *self.window_cx.app
1547 }
1548}
1549
1550impl<V> Borrow<Window> for ViewContext<'_, V> {
1551 fn borrow(&self) -> &Window {
1552 &*self.window_cx.window
1553 }
1554}
1555
1556impl<V> BorrowMut<Window> for ViewContext<'_, V> {
1557 fn borrow_mut(&mut self) -> &mut Window {
1558 &mut *self.window_cx.window
1559 }
1560}
1561
1562impl<'a, V: 'static> ViewContext<'a, V> {
1563 pub(crate) fn new(app: &'a mut AppContext, window: &'a mut Window, view: &'a View<V>) -> Self {
1564 Self {
1565 window_cx: WindowContext::new(app, window),
1566 view,
1567 }
1568 }
1569
1570 pub fn view(&self) -> View<V> {
1571 self.view.clone()
1572 }
1573
1574 pub fn model(&self) -> Model<V> {
1575 self.view.model.clone()
1576 }
1577
1578 pub fn stack<R>(&mut self, order: u32, f: impl FnOnce(&mut Self) -> R) -> R {
1579 self.window.z_index_stack.push(order);
1580 let result = f(self);
1581 self.window.z_index_stack.pop();
1582 result
1583 }
1584
1585 pub fn on_next_frame(&mut self, f: impl FnOnce(&mut V, &mut ViewContext<V>) + Send + 'static)
1586 where
1587 V: Any + Send,
1588 {
1589 let view = self.view();
1590 self.window_cx.on_next_frame(move |cx| view.update(cx, f));
1591 }
1592
1593 /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
1594 /// that are currently on the stack to be returned to the app.
1595 pub fn defer(&mut self, f: impl FnOnce(&mut V, &mut ViewContext<V>) + 'static + Send) {
1596 let view = self.view().downgrade();
1597 self.window_cx.defer(move |cx| {
1598 view.update(cx, f).ok();
1599 });
1600 }
1601
1602 pub fn observe<V2, E>(
1603 &mut self,
1604 entity: &E,
1605 mut on_notify: impl FnMut(&mut V, E, &mut ViewContext<'_, V>) + Send + 'static,
1606 ) -> Subscription
1607 where
1608 V2: 'static,
1609 V: 'static + Send,
1610 E: Entity<V2>,
1611 {
1612 let view = self.view().downgrade();
1613 let entity_id = entity.entity_id();
1614 let entity = entity.downgrade();
1615 let window_handle = self.window.handle;
1616 self.app.observers.insert(
1617 entity_id,
1618 Box::new(move |cx| {
1619 cx.update_window(window_handle, |cx| {
1620 if let Some(handle) = E::upgrade_from(&entity) {
1621 view.update(cx, |this, cx| on_notify(this, handle, cx))
1622 .is_ok()
1623 } else {
1624 false
1625 }
1626 })
1627 .unwrap_or(false)
1628 }),
1629 )
1630 }
1631
1632 pub fn subscribe<V2, E>(
1633 &mut self,
1634 entity: &E,
1635 mut on_event: impl FnMut(&mut V, E, &V2::Event, &mut ViewContext<'_, V>) + Send + 'static,
1636 ) -> Subscription
1637 where
1638 V2: EventEmitter,
1639 E: Entity<V2>,
1640 {
1641 let view = self.view().downgrade();
1642 let entity_id = entity.entity_id();
1643 let handle = entity.downgrade();
1644 let window_handle = self.window.handle;
1645 self.app.event_listeners.insert(
1646 entity_id,
1647 Box::new(move |event, cx| {
1648 cx.update_window(window_handle, |cx| {
1649 if let Some(handle) = E::upgrade_from(&handle) {
1650 let event = event.downcast_ref().expect("invalid event type");
1651 view.update(cx, |this, cx| on_event(this, handle, event, cx))
1652 .is_ok()
1653 } else {
1654 false
1655 }
1656 })
1657 .unwrap_or(false)
1658 }),
1659 )
1660 }
1661
1662 pub fn on_release(
1663 &mut self,
1664 on_release: impl FnOnce(&mut V, &mut WindowContext) + Send + 'static,
1665 ) -> Subscription {
1666 let window_handle = self.window.handle;
1667 self.app.release_listeners.insert(
1668 self.view.model.entity_id,
1669 Box::new(move |this, cx| {
1670 let this = this.downcast_mut().expect("invalid entity type");
1671 // todo!("are we okay with silently swallowing the error?")
1672 let _ = cx.update_window(window_handle, |cx| on_release(this, cx));
1673 }),
1674 )
1675 }
1676
1677 pub fn observe_release<V2, E>(
1678 &mut self,
1679 entity: &E,
1680 mut on_release: impl FnMut(&mut V, &mut V2, &mut ViewContext<'_, V>) + Send + 'static,
1681 ) -> Subscription
1682 where
1683 V: Any + Send,
1684 V2: 'static,
1685 E: Entity<V2>,
1686 {
1687 let view = self.view().downgrade();
1688 let entity_id = entity.entity_id();
1689 let window_handle = self.window.handle;
1690 self.app.release_listeners.insert(
1691 entity_id,
1692 Box::new(move |entity, cx| {
1693 let entity = entity.downcast_mut().expect("invalid entity type");
1694 let _ = cx.update_window(window_handle, |cx| {
1695 view.update(cx, |this, cx| on_release(this, entity, cx))
1696 });
1697 }),
1698 )
1699 }
1700
1701 pub fn notify(&mut self) {
1702 self.window_cx.notify();
1703 self.window_cx.app.push_effect(Effect::Notify {
1704 emitter: self.view.model.entity_id,
1705 });
1706 }
1707
1708 pub fn on_focus_changed(
1709 &mut self,
1710 listener: impl Fn(&mut V, &FocusEvent, &mut ViewContext<V>) + Send + 'static,
1711 ) {
1712 let handle = self.view().downgrade();
1713 self.window.focus_listeners.push(Box::new(move |event, cx| {
1714 handle
1715 .update(cx, |view, cx| listener(view, event, cx))
1716 .log_err();
1717 }));
1718 }
1719
1720 pub fn with_key_listeners<R>(
1721 &mut self,
1722 key_listeners: impl IntoIterator<Item = (TypeId, KeyListener<V>)>,
1723 f: impl FnOnce(&mut Self) -> R,
1724 ) -> R {
1725 let old_stack_len = self.window.key_dispatch_stack.len();
1726 if !self.window.freeze_key_dispatch_stack {
1727 for (event_type, listener) in key_listeners {
1728 let handle = self.view().downgrade();
1729 let listener = Box::new(
1730 move |event: &dyn Any,
1731 context_stack: &[&DispatchContext],
1732 phase: DispatchPhase,
1733 cx: &mut WindowContext<'_>| {
1734 handle
1735 .update(cx, |view, cx| {
1736 listener(view, event, context_stack, phase, cx)
1737 })
1738 .log_err()
1739 .flatten()
1740 },
1741 );
1742 self.window
1743 .key_dispatch_stack
1744 .push(KeyDispatchStackFrame::Listener {
1745 event_type,
1746 listener,
1747 });
1748 }
1749 }
1750
1751 let result = f(self);
1752
1753 if !self.window.freeze_key_dispatch_stack {
1754 self.window.key_dispatch_stack.truncate(old_stack_len);
1755 }
1756
1757 result
1758 }
1759
1760 pub fn with_key_dispatch_context<R>(
1761 &mut self,
1762 context: DispatchContext,
1763 f: impl FnOnce(&mut Self) -> R,
1764 ) -> R {
1765 if context.is_empty() {
1766 return f(self);
1767 }
1768
1769 if !self.window.freeze_key_dispatch_stack {
1770 self.window
1771 .key_dispatch_stack
1772 .push(KeyDispatchStackFrame::Context(context));
1773 }
1774
1775 let result = f(self);
1776
1777 if !self.window.freeze_key_dispatch_stack {
1778 self.window.key_dispatch_stack.pop();
1779 }
1780
1781 result
1782 }
1783
1784 pub fn with_focus<R>(
1785 &mut self,
1786 focus_handle: FocusHandle,
1787 f: impl FnOnce(&mut Self) -> R,
1788 ) -> R {
1789 if let Some(parent_focus_id) = self.window.focus_stack.last().copied() {
1790 self.window
1791 .focus_parents_by_child
1792 .insert(focus_handle.id, parent_focus_id);
1793 }
1794 self.window.focus_stack.push(focus_handle.id);
1795
1796 if Some(focus_handle.id) == self.window.focus {
1797 self.window.freeze_key_dispatch_stack = true;
1798 }
1799
1800 let result = f(self);
1801
1802 self.window.focus_stack.pop();
1803 result
1804 }
1805
1806 pub fn run_on_main<R>(
1807 &mut self,
1808 view: &mut V,
1809 f: impl FnOnce(&mut V, &mut MainThread<ViewContext<'_, V>>) -> R + Send + 'static,
1810 ) -> Task<Result<R>>
1811 where
1812 R: Send + 'static,
1813 {
1814 if self.executor.is_main_thread() {
1815 let cx = unsafe { mem::transmute::<&mut Self, &mut MainThread<Self>>(self) };
1816 Task::ready(Ok(f(view, cx)))
1817 } else {
1818 let view = self.view();
1819 self.window_cx.run_on_main(move |cx| view.update(cx, f))
1820 }
1821 }
1822
1823 pub fn spawn<Fut, R>(
1824 &mut self,
1825 f: impl FnOnce(WeakView<V>, AsyncWindowContext) -> Fut + Send + 'static,
1826 ) -> Task<R>
1827 where
1828 R: Send + 'static,
1829 Fut: Future<Output = R> + Send + 'static,
1830 {
1831 let view = self.view().downgrade();
1832 self.window_cx.spawn(move |_, cx| {
1833 let result = f(view, cx);
1834 async move { result.await }
1835 })
1836 }
1837
1838 pub fn update_global<G, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R
1839 where
1840 G: 'static + Send,
1841 {
1842 let mut global = self.app.lease_global::<G>();
1843 let result = f(&mut global, self);
1844 self.app.end_global_lease(global);
1845 result
1846 }
1847
1848 pub fn observe_global<G: 'static>(
1849 &mut self,
1850 f: impl Fn(&mut V, &mut ViewContext<'_, V>) + Send + 'static,
1851 ) -> Subscription {
1852 let window_handle = self.window.handle;
1853 let view = self.view().downgrade();
1854 self.global_observers.insert(
1855 TypeId::of::<G>(),
1856 Box::new(move |cx| {
1857 cx.update_window(window_handle, |cx| {
1858 view.update(cx, |view, cx| f(view, cx)).is_ok()
1859 })
1860 .unwrap_or(false)
1861 }),
1862 )
1863 }
1864
1865 pub fn on_mouse_event<Event: 'static>(
1866 &mut self,
1867 handler: impl Fn(&mut V, &Event, DispatchPhase, &mut ViewContext<V>) + Send + 'static,
1868 ) {
1869 let handle = self.view();
1870 self.window_cx.on_mouse_event(move |event, phase, cx| {
1871 handle.update(cx, |view, cx| {
1872 handler(view, event, phase, cx);
1873 })
1874 });
1875 }
1876}
1877
1878impl<V> ViewContext<'_, V>
1879where
1880 V: EventEmitter,
1881 V::Event: 'static + Send,
1882{
1883 pub fn emit(&mut self, event: V::Event) {
1884 let emitter = self.view.model.entity_id;
1885 self.app.push_effect(Effect::Emit {
1886 emitter,
1887 event: Box::new(event),
1888 });
1889 }
1890}
1891
1892impl<V: 'static> MainThread<ViewContext<'_, V>> {
1893 fn platform_window(&self) -> &dyn PlatformWindow {
1894 self.window.platform_window.borrow_on_main_thread().as_ref()
1895 }
1896
1897 pub fn activate_window(&self) {
1898 self.platform_window().activate();
1899 }
1900}
1901
1902impl<V> Context for ViewContext<'_, V> {
1903 type ModelContext<'b, U> = ModelContext<'b, U>;
1904 type Result<U> = U;
1905
1906 fn build_model<T>(
1907 &mut self,
1908 build_model: impl FnOnce(&mut Self::ModelContext<'_, T>) -> T,
1909 ) -> Model<T>
1910 where
1911 T: 'static + Send,
1912 {
1913 self.window_cx.build_model(build_model)
1914 }
1915
1916 fn update_model<T: 'static, R>(
1917 &mut self,
1918 model: &Model<T>,
1919 update: impl FnOnce(&mut T, &mut Self::ModelContext<'_, T>) -> R,
1920 ) -> R {
1921 self.window_cx.update_model(model, update)
1922 }
1923}
1924
1925impl<V: 'static> VisualContext for ViewContext<'_, V> {
1926 type ViewContext<'a, W: 'static> = ViewContext<'a, W>;
1927
1928 fn build_view<W: 'static + Send>(
1929 &mut self,
1930 build_view: impl FnOnce(&mut Self::ViewContext<'_, W>) -> W,
1931 ) -> Self::Result<View<W>> {
1932 self.window_cx.build_view(build_view)
1933 }
1934
1935 fn update_view<V2: 'static, R>(
1936 &mut self,
1937 view: &View<V2>,
1938 update: impl FnOnce(&mut V2, &mut Self::ViewContext<'_, V2>) -> R,
1939 ) -> Self::Result<R> {
1940 self.window_cx.update_view(view, update)
1941 }
1942}
1943
1944impl<'a, V> std::ops::Deref for ViewContext<'a, V> {
1945 type Target = WindowContext<'a>;
1946
1947 fn deref(&self) -> &Self::Target {
1948 &self.window_cx
1949 }
1950}
1951
1952impl<'a, V> std::ops::DerefMut for ViewContext<'a, V> {
1953 fn deref_mut(&mut self) -> &mut Self::Target {
1954 &mut self.window_cx
1955 }
1956}
1957
1958// #[derive(Clone, Copy, Eq, PartialEq, Hash)]
1959slotmap::new_key_type! { pub struct WindowId; }
1960
1961impl WindowId {
1962 pub fn as_u64(&self) -> u64 {
1963 self.0.as_ffi()
1964 }
1965}
1966
1967#[derive(PartialEq, Eq, Deref, DerefMut)]
1968pub struct WindowHandle<V> {
1969 #[deref]
1970 #[deref_mut]
1971 pub(crate) any_handle: AnyWindowHandle,
1972 state_type: PhantomData<V>,
1973}
1974
1975impl<V> Copy for WindowHandle<V> {}
1976
1977impl<V> Clone for WindowHandle<V> {
1978 fn clone(&self) -> Self {
1979 WindowHandle {
1980 any_handle: self.any_handle,
1981 state_type: PhantomData,
1982 }
1983 }
1984}
1985
1986impl<V: 'static> WindowHandle<V> {
1987 pub fn new(id: WindowId) -> Self {
1988 WindowHandle {
1989 any_handle: AnyWindowHandle {
1990 id,
1991 state_type: TypeId::of::<V>(),
1992 },
1993 state_type: PhantomData,
1994 }
1995 }
1996
1997 pub fn update<R>(
1998 &self,
1999 cx: &mut AppContext,
2000 update: impl FnOnce(&mut V, &mut ViewContext<V>) -> R,
2001 ) -> Result<R> {
2002 cx.update_window(self.any_handle, |cx| {
2003 let root_view = cx
2004 .window
2005 .root_view
2006 .clone()
2007 .unwrap()
2008 .downcast::<V>()
2009 .unwrap();
2010 root_view.update(cx, update)
2011 })
2012 }
2013}
2014
2015impl<V: 'static> Into<AnyWindowHandle> for WindowHandle<V> {
2016 fn into(self) -> AnyWindowHandle {
2017 self.any_handle
2018 }
2019}
2020
2021#[derive(Copy, Clone, PartialEq, Eq)]
2022pub struct AnyWindowHandle {
2023 pub(crate) id: WindowId,
2024 state_type: TypeId,
2025}
2026
2027impl AnyWindowHandle {
2028 pub fn window_id(&self) -> WindowId {
2029 self.id
2030 }
2031
2032 pub fn downcast<T: 'static>(&self) -> Option<WindowHandle<T>> {
2033 if TypeId::of::<T>() == self.state_type {
2034 Some(WindowHandle {
2035 any_handle: *self,
2036 state_type: PhantomData,
2037 })
2038 } else {
2039 None
2040 }
2041 }
2042}
2043
2044#[cfg(any(test, feature = "test-support"))]
2045impl From<SmallVec<[u32; 16]>> for StackingOrder {
2046 fn from(small_vec: SmallVec<[u32; 16]>) -> Self {
2047 StackingOrder(small_vec)
2048 }
2049}
2050
2051#[derive(Clone, Debug, Eq, PartialEq, Hash)]
2052pub enum ElementId {
2053 View(EntityId),
2054 Number(usize),
2055 Name(SharedString),
2056 FocusHandle(FocusId),
2057}
2058
2059impl From<EntityId> for ElementId {
2060 fn from(id: EntityId) -> Self {
2061 ElementId::View(id)
2062 }
2063}
2064
2065impl From<usize> for ElementId {
2066 fn from(id: usize) -> Self {
2067 ElementId::Number(id)
2068 }
2069}
2070
2071impl From<i32> for ElementId {
2072 fn from(id: i32) -> Self {
2073 Self::Number(id as usize)
2074 }
2075}
2076
2077impl From<SharedString> for ElementId {
2078 fn from(name: SharedString) -> Self {
2079 ElementId::Name(name)
2080 }
2081}
2082
2083impl From<&'static str> for ElementId {
2084 fn from(name: &'static str) -> Self {
2085 ElementId::Name(name.into())
2086 }
2087}
2088
2089impl<'a> From<&'a FocusHandle> for ElementId {
2090 fn from(handle: &'a FocusHandle) -> Self {
2091 ElementId::FocusHandle(handle.id)
2092 }
2093}