1use crate::{
2 px, size, Action, AnyBox, AnyDrag, AnyView, AppContext, AsyncWindowContext, AvailableSpace,
3 Bounds, BoxShadow, Context, Corners, CursorStyle, DevicePixels, DispatchContext, DisplayId,
4 Edges, Effect, Entity, EntityId, EventEmitter, FileDropEvent, FocusEvent, FontId,
5 GlobalElementId, GlyphId, Hsla, ImageData, InputEvent, IsZero, KeyListener, KeyMatch,
6 KeyMatcher, Keystroke, LayoutId, Model, ModelContext, Modifiers, MonochromeSprite, MouseButton,
7 MouseDownEvent, MouseMoveEvent, MouseUpEvent, Path, Pixels, PlatformAtlas, PlatformDisplay,
8 PlatformInputHandler, PlatformWindow, Point, PolychromeSprite, PromptLevel, Quad, Render,
9 RenderGlyphParams, RenderImageParams, RenderSvgParams, ScaledPixels, SceneBuilder, Shadow,
10 SharedString, Size, Style, SubscriberSet, Subscription, TaffyLayoutEngine, Task, Underline,
11 UnderlineStyle, View, VisualContext, WeakView, WindowBounds, WindowOptions, SUBPIXEL_VARIANTS,
12};
13use anyhow::{anyhow, Result};
14use collections::HashMap;
15use derive_more::{Deref, DerefMut};
16use futures::{
17 channel::{mpsc, oneshot},
18 StreamExt,
19};
20use parking_lot::RwLock;
21use slotmap::SlotMap;
22use smallvec::SmallVec;
23use std::{
24 any::{Any, TypeId},
25 borrow::{Borrow, BorrowMut, Cow},
26 fmt::Debug,
27 future::Future,
28 hash::{Hash, Hasher},
29 marker::PhantomData,
30 mem,
31 rc::Rc,
32 sync::{
33 atomic::{AtomicUsize, Ordering::SeqCst},
34 Arc,
35 },
36};
37use util::ResultExt;
38
39/// A global stacking order, which is created by stacking successive z-index values.
40/// Each z-index will always be interpreted in the context of its parent z-index.
41#[derive(Deref, DerefMut, Ord, PartialOrd, Eq, PartialEq, Clone, Default)]
42pub(crate) struct StackingOrder(pub(crate) SmallVec<[u32; 16]>);
43
44/// Represents the two different phases when dispatching events.
45#[derive(Default, Copy, Clone, Debug, Eq, PartialEq)]
46pub enum DispatchPhase {
47 /// After the capture phase comes the bubble phase, in which mouse event listeners are
48 /// invoked front to back and keyboard event listeners are invoked from the focused element
49 /// to the root of the element tree. This is the phase you'll most commonly want to use when
50 /// registering event listeners.
51 #[default]
52 Bubble,
53 /// During the initial capture phase, mouse event listeners are invoked back to front, and keyboard
54 /// listeners are invoked from the root of the tree downward toward the focused element. This phase
55 /// is used for special purposes such as clearing the "pressed" state for click events. If
56 /// you stop event propagation during this phase, you need to know what you're doing. Handlers
57 /// outside of the immediate region may rely on detecting non-local events during this phase.
58 Capture,
59}
60
61type AnyObserver = Box<dyn FnMut(&mut WindowContext) -> bool + 'static>;
62type AnyListener = Box<dyn FnMut(&dyn Any, DispatchPhase, &mut WindowContext) + 'static>;
63type AnyKeyListener = Box<
64 dyn Fn(
65 &dyn Any,
66 &[&DispatchContext],
67 DispatchPhase,
68 &mut WindowContext,
69 ) -> Option<Box<dyn Action>>
70 + 'static,
71>;
72type AnyFocusListener = Box<dyn Fn(&FocusEvent, &mut WindowContext) + 'static>;
73type AnyWindowFocusListener = Box<dyn FnMut(&FocusEvent, &mut WindowContext) -> bool + 'static>;
74
75slotmap::new_key_type! { pub struct FocusId; }
76
77impl FocusId {
78 /// Obtains whether the element associated with this handle is currently focused.
79 pub fn is_focused(&self, cx: &WindowContext) -> bool {
80 cx.window.focus == Some(*self)
81 }
82
83 /// Obtains whether the element associated with this handle contains the focused
84 /// element or is itself focused.
85 pub fn contains_focused(&self, cx: &WindowContext) -> bool {
86 cx.focused()
87 .map_or(false, |focused| self.contains(focused.id, cx))
88 }
89
90 /// Obtains whether the element associated with this handle is contained within the
91 /// focused element or is itself focused.
92 pub fn within_focused(&self, cx: &WindowContext) -> bool {
93 let focused = cx.focused();
94 focused.map_or(false, |focused| focused.id.contains(*self, cx))
95 }
96
97 /// Obtains whether this handle contains the given handle in the most recently rendered frame.
98 pub(crate) fn contains(&self, other: Self, cx: &WindowContext) -> bool {
99 let mut ancestor = Some(other);
100 while let Some(ancestor_id) = ancestor {
101 if *self == ancestor_id {
102 return true;
103 } else {
104 ancestor = cx
105 .window
106 .current_frame
107 .focus_parents_by_child
108 .get(&ancestor_id)
109 .copied();
110 }
111 }
112 false
113 }
114}
115
116/// A handle which can be used to track and manipulate the focused element in a window.
117pub struct FocusHandle {
118 pub(crate) id: FocusId,
119 handles: Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>,
120}
121
122impl FocusHandle {
123 pub(crate) fn new(handles: &Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>) -> Self {
124 let id = handles.write().insert(AtomicUsize::new(1));
125 Self {
126 id,
127 handles: handles.clone(),
128 }
129 }
130
131 pub(crate) fn for_id(
132 id: FocusId,
133 handles: &Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>,
134 ) -> Option<Self> {
135 let lock = handles.read();
136 let ref_count = lock.get(id)?;
137 if ref_count.load(SeqCst) == 0 {
138 None
139 } else {
140 ref_count.fetch_add(1, SeqCst);
141 Some(Self {
142 id,
143 handles: handles.clone(),
144 })
145 }
146 }
147
148 /// Obtains whether the element associated with this handle is currently focused.
149 pub fn is_focused(&self, cx: &WindowContext) -> bool {
150 self.id.is_focused(cx)
151 }
152
153 /// Obtains whether the element associated with this handle contains the focused
154 /// element or is itself focused.
155 pub fn contains_focused(&self, cx: &WindowContext) -> bool {
156 self.id.contains_focused(cx)
157 }
158
159 /// Obtains whether the element associated with this handle is contained within the
160 /// focused element or is itself focused.
161 pub fn within_focused(&self, cx: &WindowContext) -> bool {
162 self.id.within_focused(cx)
163 }
164
165 /// Obtains whether this handle contains the given handle in the most recently rendered frame.
166 pub(crate) fn contains(&self, other: &Self, cx: &WindowContext) -> bool {
167 self.id.contains(other.id, cx)
168 }
169}
170
171impl Clone for FocusHandle {
172 fn clone(&self) -> Self {
173 Self::for_id(self.id, &self.handles).unwrap()
174 }
175}
176
177impl PartialEq for FocusHandle {
178 fn eq(&self, other: &Self) -> bool {
179 self.id == other.id
180 }
181}
182
183impl Eq for FocusHandle {}
184
185impl Drop for FocusHandle {
186 fn drop(&mut self) {
187 self.handles
188 .read()
189 .get(self.id)
190 .unwrap()
191 .fetch_sub(1, SeqCst);
192 }
193}
194
195// Holds the state for a specific window.
196pub struct Window {
197 pub(crate) handle: AnyWindowHandle,
198 pub(crate) removed: bool,
199 platform_window: Box<dyn PlatformWindow>,
200 display_id: DisplayId,
201 sprite_atlas: Arc<dyn PlatformAtlas>,
202 rem_size: Pixels,
203 content_size: Size<Pixels>,
204 pub(crate) layout_engine: TaffyLayoutEngine,
205 pub(crate) root_view: Option<AnyView>,
206 pub(crate) element_id_stack: GlobalElementId,
207 pub(crate) previous_frame: Frame,
208 pub(crate) current_frame: Frame,
209 pub(crate) focus_handles: Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>,
210 pub(crate) focus_listeners: SubscriberSet<(), AnyWindowFocusListener>,
211 default_prevented: bool,
212 mouse_position: Point<Pixels>,
213 requested_cursor_style: Option<CursorStyle>,
214 scale_factor: f32,
215 bounds: WindowBounds,
216 bounds_observers: SubscriberSet<(), AnyObserver>,
217 active: bool,
218 activation_observers: SubscriberSet<(), AnyObserver>,
219 pub(crate) dirty: bool,
220 pub(crate) last_blur: Option<Option<FocusId>>,
221 pub(crate) focus: Option<FocusId>,
222}
223
224#[derive(Default)]
225pub(crate) struct Frame {
226 element_states: HashMap<GlobalElementId, AnyBox>,
227 key_matchers: HashMap<GlobalElementId, KeyMatcher>,
228 mouse_listeners: HashMap<TypeId, Vec<(StackingOrder, AnyListener)>>,
229 pub(crate) focus_listeners: Vec<AnyFocusListener>,
230 key_dispatch_stack: Vec<KeyDispatchStackFrame>,
231 freeze_key_dispatch_stack: bool,
232 focus_parents_by_child: HashMap<FocusId, FocusId>,
233 pub(crate) scene_builder: SceneBuilder,
234 z_index_stack: StackingOrder,
235 content_mask_stack: Vec<ContentMask<Pixels>>,
236 element_offset_stack: Vec<Point<Pixels>>,
237 focus_stack: Vec<FocusId>,
238}
239
240impl Window {
241 pub(crate) fn new(
242 handle: AnyWindowHandle,
243 options: WindowOptions,
244 cx: &mut AppContext,
245 ) -> Self {
246 let platform_window = cx.platform.open_window(handle, options);
247 let display_id = platform_window.display().id();
248 let sprite_atlas = platform_window.sprite_atlas();
249 let mouse_position = platform_window.mouse_position();
250 let content_size = platform_window.content_size();
251 let scale_factor = platform_window.scale_factor();
252 let bounds = platform_window.bounds();
253
254 platform_window.on_resize(Box::new({
255 let mut cx = cx.to_async();
256 move |_, _| {
257 handle
258 .update(&mut cx, |_, cx| cx.window_bounds_changed())
259 .log_err();
260 }
261 }));
262 platform_window.on_moved(Box::new({
263 let mut cx = cx.to_async();
264 move || {
265 handle
266 .update(&mut cx, |_, cx| cx.window_bounds_changed())
267 .log_err();
268 }
269 }));
270 platform_window.on_active_status_change(Box::new({
271 let mut cx = cx.to_async();
272 move |active| {
273 handle
274 .update(&mut cx, |_, cx| {
275 cx.window.active = active;
276 cx.window
277 .activation_observers
278 .clone()
279 .retain(&(), |callback| callback(cx));
280 })
281 .log_err();
282 }
283 }));
284
285 platform_window.on_input({
286 let mut cx = cx.to_async();
287 Box::new(move |event| {
288 handle
289 .update(&mut cx, |_, cx| cx.dispatch_event(event))
290 .log_err()
291 .unwrap_or(false)
292 })
293 });
294
295 Window {
296 handle,
297 removed: false,
298 platform_window,
299 display_id,
300 sprite_atlas,
301 rem_size: px(16.),
302 content_size,
303 layout_engine: TaffyLayoutEngine::new(),
304 root_view: None,
305 element_id_stack: GlobalElementId::default(),
306 previous_frame: Frame::default(),
307 current_frame: Frame::default(),
308 focus_handles: Arc::new(RwLock::new(SlotMap::with_key())),
309 focus_listeners: SubscriberSet::new(),
310 default_prevented: true,
311 mouse_position,
312 requested_cursor_style: None,
313 scale_factor,
314 bounds,
315 bounds_observers: SubscriberSet::new(),
316 active: false,
317 activation_observers: SubscriberSet::new(),
318 dirty: true,
319 last_blur: None,
320 focus: None,
321 }
322 }
323}
324
325/// When constructing the element tree, we maintain a stack of key dispatch frames until we
326/// find the focused element. We interleave key listeners with dispatch contexts so we can use the
327/// contexts when matching key events against the keymap. A key listener can be either an action
328/// handler or a [KeyDown] / [KeyUp] event listener.
329enum KeyDispatchStackFrame {
330 Listener {
331 event_type: TypeId,
332 listener: AnyKeyListener,
333 },
334 Context(DispatchContext),
335}
336
337/// Indicates which region of the window is visible. Content falling outside of this mask will not be
338/// rendered. Currently, only rectangular content masks are supported, but we give the mask its own type
339/// to leave room to support more complex shapes in the future.
340#[derive(Clone, Debug, Default, PartialEq, Eq)]
341#[repr(C)]
342pub struct ContentMask<P: Clone + Default + Debug> {
343 pub bounds: Bounds<P>,
344}
345
346impl ContentMask<Pixels> {
347 /// Scale the content mask's pixel units by the given scaling factor.
348 pub fn scale(&self, factor: f32) -> ContentMask<ScaledPixels> {
349 ContentMask {
350 bounds: self.bounds.scale(factor),
351 }
352 }
353
354 /// Intersect the content mask with the given content mask.
355 pub fn intersect(&self, other: &Self) -> Self {
356 let bounds = self.bounds.intersect(&other.bounds);
357 ContentMask { bounds }
358 }
359}
360
361/// Provides access to application state in the context of a single window. Derefs
362/// to an `AppContext`, so you can also pass a `WindowContext` to any method that takes
363/// an `AppContext` and call any `AppContext` methods.
364pub struct WindowContext<'a> {
365 pub(crate) app: &'a mut AppContext,
366 pub(crate) window: &'a mut Window,
367}
368
369impl<'a> WindowContext<'a> {
370 pub(crate) fn new(app: &'a mut AppContext, window: &'a mut Window) -> Self {
371 Self { app, window }
372 }
373
374 /// Obtain a handle to the window that belongs to this context.
375 pub fn window_handle(&self) -> AnyWindowHandle {
376 self.window.handle
377 }
378
379 /// Mark the window as dirty, scheduling it to be redrawn on the next frame.
380 pub fn notify(&mut self) {
381 self.window.dirty = true;
382 }
383
384 /// Close this window.
385 pub fn remove_window(&mut self) {
386 self.window.removed = true;
387 }
388
389 /// Obtain a new `FocusHandle`, which allows you to track and manipulate the keyboard focus
390 /// for elements rendered within this window.
391 pub fn focus_handle(&mut self) -> FocusHandle {
392 FocusHandle::new(&self.window.focus_handles)
393 }
394
395 /// Obtain the currently focused `FocusHandle`. If no elements are focused, returns `None`.
396 pub fn focused(&self) -> Option<FocusHandle> {
397 self.window
398 .focus
399 .and_then(|id| FocusHandle::for_id(id, &self.window.focus_handles))
400 }
401
402 /// Move focus to the element associated with the given `FocusHandle`.
403 pub fn focus(&mut self, handle: &FocusHandle) {
404 if self.window.last_blur.is_none() {
405 self.window.last_blur = Some(self.window.focus);
406 }
407
408 self.window.focus = Some(handle.id);
409 self.app.push_effect(Effect::FocusChanged {
410 window_handle: self.window.handle,
411 focused: Some(handle.id),
412 });
413 self.notify();
414 }
415
416 /// Remove focus from all elements within this context's window.
417 pub fn blur(&mut self) {
418 if self.window.last_blur.is_none() {
419 self.window.last_blur = Some(self.window.focus);
420 }
421
422 self.window.focus = None;
423 self.app.push_effect(Effect::FocusChanged {
424 window_handle: self.window.handle,
425 focused: None,
426 });
427 self.notify();
428 }
429
430 /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
431 /// that are currently on the stack to be returned to the app.
432 pub fn defer(&mut self, f: impl FnOnce(&mut WindowContext) + 'static) {
433 let handle = self.window.handle;
434 self.app.defer(move |cx| {
435 handle.update(cx, |_, cx| f(cx)).ok();
436 });
437 }
438
439 pub fn subscribe<Emitter, E>(
440 &mut self,
441 entity: &E,
442 mut on_event: impl FnMut(E, &Emitter::Event, &mut WindowContext<'_>) + 'static,
443 ) -> Subscription
444 where
445 Emitter: EventEmitter,
446 E: Entity<Emitter>,
447 {
448 let entity_id = entity.entity_id();
449 let entity = entity.downgrade();
450 let window_handle = self.window.handle;
451 self.app.event_listeners.insert(
452 entity_id,
453 Box::new(move |event, cx| {
454 window_handle
455 .update(cx, |_, cx| {
456 if let Some(handle) = E::upgrade_from(&entity) {
457 let event = event.downcast_ref().expect("invalid event type");
458 on_event(handle, event, cx);
459 true
460 } else {
461 false
462 }
463 })
464 .unwrap_or(false)
465 }),
466 )
467 }
468
469 /// Create an `AsyncWindowContext`, which has a static lifetime and can be held across
470 /// await points in async code.
471 pub fn to_async(&self) -> AsyncWindowContext {
472 AsyncWindowContext::new(self.app.to_async(), self.window.handle)
473 }
474
475 /// Schedule the given closure to be run directly after the current frame is rendered.
476 pub fn on_next_frame(&mut self, callback: impl FnOnce(&mut WindowContext) + 'static) {
477 let handle = self.window.handle;
478 let display_id = self.window.display_id;
479
480 if !self.frame_consumers.contains_key(&display_id) {
481 let (tx, mut rx) = mpsc::unbounded::<()>();
482 self.platform.set_display_link_output_callback(
483 display_id,
484 Box::new(move |_current_time, _output_time| _ = tx.unbounded_send(())),
485 );
486
487 let consumer_task = self.app.spawn(|cx| async move {
488 while rx.next().await.is_some() {
489 cx.update(|cx| {
490 for callback in cx
491 .next_frame_callbacks
492 .get_mut(&display_id)
493 .unwrap()
494 .drain(..)
495 .collect::<SmallVec<[_; 32]>>()
496 {
497 callback(cx);
498 }
499 })
500 .ok();
501
502 // Flush effects, then stop the display link if no new next_frame_callbacks have been added.
503
504 cx.update(|cx| {
505 if cx.next_frame_callbacks.is_empty() {
506 cx.platform.stop_display_link(display_id);
507 }
508 })
509 .ok();
510 }
511 });
512 self.frame_consumers.insert(display_id, consumer_task);
513 }
514
515 if self.next_frame_callbacks.is_empty() {
516 self.platform.start_display_link(display_id);
517 }
518
519 self.next_frame_callbacks
520 .entry(display_id)
521 .or_default()
522 .push(Box::new(move |cx: &mut AppContext| {
523 cx.update_window(handle, |_root_view, cx| callback(cx)).ok();
524 }));
525 }
526
527 /// Spawn the future returned by the given closure on the application thread pool.
528 /// The closure is provided a handle to the current window and an `AsyncWindowContext` for
529 /// use within your future.
530 pub fn spawn<Fut, R>(&mut self, f: impl FnOnce(AsyncWindowContext) -> Fut) -> Task<R>
531 where
532 R: 'static,
533 Fut: Future<Output = R> + 'static,
534 {
535 self.app
536 .spawn(|app| f(AsyncWindowContext::new(app, self.window.handle)))
537 }
538
539 /// Update the global of the given type. The given closure is given simultaneous mutable
540 /// access both to the global and the context.
541 pub fn update_global<G, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R
542 where
543 G: 'static,
544 {
545 let mut global = self.app.lease_global::<G>();
546 let result = f(&mut global, self);
547 self.app.end_global_lease(global);
548 result
549 }
550
551 /// Add a node to the layout tree for the current frame. Takes the `Style` of the element for which
552 /// layout is being requested, along with the layout ids of any children. This method is called during
553 /// calls to the `Element::layout` trait method and enables any element to participate in layout.
554 pub fn request_layout(
555 &mut self,
556 style: &Style,
557 children: impl IntoIterator<Item = LayoutId>,
558 ) -> LayoutId {
559 self.app.layout_id_buffer.clear();
560 self.app.layout_id_buffer.extend(children.into_iter());
561 let rem_size = self.rem_size();
562
563 self.window
564 .layout_engine
565 .request_layout(style, rem_size, &self.app.layout_id_buffer)
566 }
567
568 /// Add a node to the layout tree for the current frame. Instead of taking a `Style` and children,
569 /// this variant takes a function that is invoked during layout so you can use arbitrary logic to
570 /// determine the element's size. One place this is used internally is when measuring text.
571 ///
572 /// The given closure is invoked at layout time with the known dimensions and available space and
573 /// returns a `Size`.
574 pub fn request_measured_layout<
575 F: Fn(Size<Option<Pixels>>, Size<AvailableSpace>) -> Size<Pixels> + Send + Sync + 'static,
576 >(
577 &mut self,
578 style: Style,
579 rem_size: Pixels,
580 measure: F,
581 ) -> LayoutId {
582 self.window
583 .layout_engine
584 .request_measured_layout(style, rem_size, measure)
585 }
586
587 pub fn compute_layout(&mut self, layout_id: LayoutId, available_space: Size<AvailableSpace>) {
588 self.window
589 .layout_engine
590 .compute_layout(layout_id, available_space)
591 }
592
593 /// Obtain the bounds computed for the given LayoutId relative to the window. This method should not
594 /// be invoked until the paint phase begins, and will usually be invoked by GPUI itself automatically
595 /// in order to pass your element its `Bounds` automatically.
596 pub fn layout_bounds(&mut self, layout_id: LayoutId) -> Bounds<Pixels> {
597 let mut bounds = self
598 .window
599 .layout_engine
600 .layout_bounds(layout_id)
601 .map(Into::into);
602 bounds.origin += self.element_offset();
603 bounds
604 }
605
606 fn window_bounds_changed(&mut self) {
607 self.window.scale_factor = self.window.platform_window.scale_factor();
608 self.window.content_size = self.window.platform_window.content_size();
609 self.window.bounds = self.window.platform_window.bounds();
610 self.window.display_id = self.window.platform_window.display().id();
611 self.window.dirty = true;
612
613 self.window
614 .bounds_observers
615 .clone()
616 .retain(&(), |callback| callback(self));
617 }
618
619 pub fn window_bounds(&self) -> WindowBounds {
620 self.window.bounds
621 }
622
623 pub fn is_window_active(&self) -> bool {
624 self.window.active
625 }
626
627 pub fn zoom_window(&self) {
628 self.window.platform_window.zoom();
629 }
630
631 pub fn display(&self) -> Option<Rc<dyn PlatformDisplay>> {
632 self.platform
633 .displays()
634 .into_iter()
635 .find(|display| display.id() == self.window.display_id)
636 }
637
638 pub fn show_character_palette(&self) {
639 self.window.platform_window.show_character_palette();
640 }
641
642 /// The scale factor of the display associated with the window. For example, it could
643 /// return 2.0 for a "retina" display, indicating that each logical pixel should actually
644 /// be rendered as two pixels on screen.
645 pub fn scale_factor(&self) -> f32 {
646 self.window.scale_factor
647 }
648
649 /// The size of an em for the base font of the application. Adjusting this value allows the
650 /// UI to scale, just like zooming a web page.
651 pub fn rem_size(&self) -> Pixels {
652 self.window.rem_size
653 }
654
655 /// Sets the size of an em for the base font of the application. Adjusting this value allows the
656 /// UI to scale, just like zooming a web page.
657 pub fn set_rem_size(&mut self, rem_size: impl Into<Pixels>) {
658 self.window.rem_size = rem_size.into();
659 }
660
661 /// The line height associated with the current text style.
662 pub fn line_height(&self) -> Pixels {
663 let rem_size = self.rem_size();
664 let text_style = self.text_style();
665 text_style
666 .line_height
667 .to_pixels(text_style.font_size.into(), rem_size)
668 }
669
670 /// Call to prevent the default action of an event. Currently only used to prevent
671 /// parent elements from becoming focused on mouse down.
672 pub fn prevent_default(&mut self) {
673 self.window.default_prevented = true;
674 }
675
676 /// Obtain whether default has been prevented for the event currently being dispatched.
677 pub fn default_prevented(&self) -> bool {
678 self.window.default_prevented
679 }
680
681 /// Register a mouse event listener on the window for the current frame. The type of event
682 /// is determined by the first parameter of the given listener. When the next frame is rendered
683 /// the listener will be cleared.
684 ///
685 /// This is a fairly low-level method, so prefer using event handlers on elements unless you have
686 /// a specific need to register a global listener.
687 pub fn on_mouse_event<Event: 'static>(
688 &mut self,
689 handler: impl Fn(&Event, DispatchPhase, &mut WindowContext) + 'static,
690 ) {
691 let order = self.window.current_frame.z_index_stack.clone();
692 self.window
693 .current_frame
694 .mouse_listeners
695 .entry(TypeId::of::<Event>())
696 .or_default()
697 .push((
698 order,
699 Box::new(move |event: &dyn Any, phase, cx| {
700 handler(event.downcast_ref().unwrap(), phase, cx)
701 }),
702 ))
703 }
704
705 /// The position of the mouse relative to the window.
706 pub fn mouse_position(&self) -> Point<Pixels> {
707 self.window.mouse_position
708 }
709
710 pub fn set_cursor_style(&mut self, style: CursorStyle) {
711 self.window.requested_cursor_style = Some(style)
712 }
713
714 /// Called during painting to invoke the given closure in a new stacking context. The given
715 /// z-index is interpreted relative to the previous call to `stack`.
716 pub fn stack<R>(&mut self, z_index: u32, f: impl FnOnce(&mut Self) -> R) -> R {
717 self.window.current_frame.z_index_stack.push(z_index);
718 let result = f(self);
719 self.window.current_frame.z_index_stack.pop();
720 result
721 }
722
723 /// Paint one or more drop shadows into the scene for the current frame at the current z-index.
724 pub fn paint_shadows(
725 &mut self,
726 bounds: Bounds<Pixels>,
727 corner_radii: Corners<Pixels>,
728 shadows: &[BoxShadow],
729 ) {
730 let scale_factor = self.scale_factor();
731 let content_mask = self.content_mask();
732 let window = &mut *self.window;
733 for shadow in shadows {
734 let mut shadow_bounds = bounds;
735 shadow_bounds.origin += shadow.offset;
736 shadow_bounds.dilate(shadow.spread_radius);
737 window.current_frame.scene_builder.insert(
738 &window.current_frame.z_index_stack,
739 Shadow {
740 order: 0,
741 bounds: shadow_bounds.scale(scale_factor),
742 content_mask: content_mask.scale(scale_factor),
743 corner_radii: corner_radii.scale(scale_factor),
744 color: shadow.color,
745 blur_radius: shadow.blur_radius.scale(scale_factor),
746 },
747 );
748 }
749 }
750
751 /// Paint one or more quads into the scene for the current frame at the current stacking context.
752 /// Quads are colored rectangular regions with an optional background, border, and corner radius.
753 pub fn paint_quad(
754 &mut self,
755 bounds: Bounds<Pixels>,
756 corner_radii: Corners<Pixels>,
757 background: impl Into<Hsla>,
758 border_widths: Edges<Pixels>,
759 border_color: impl Into<Hsla>,
760 ) {
761 let scale_factor = self.scale_factor();
762 let content_mask = self.content_mask();
763
764 let window = &mut *self.window;
765 window.current_frame.scene_builder.insert(
766 &window.current_frame.z_index_stack,
767 Quad {
768 order: 0,
769 bounds: bounds.scale(scale_factor),
770 content_mask: content_mask.scale(scale_factor),
771 background: background.into(),
772 border_color: border_color.into(),
773 corner_radii: corner_radii.scale(scale_factor),
774 border_widths: border_widths.scale(scale_factor),
775 },
776 );
777 }
778
779 /// Paint the given `Path` into the scene for the current frame at the current z-index.
780 pub fn paint_path(&mut self, mut path: Path<Pixels>, color: impl Into<Hsla>) {
781 let scale_factor = self.scale_factor();
782 let content_mask = self.content_mask();
783 path.content_mask = content_mask;
784 path.color = color.into();
785 let window = &mut *self.window;
786 window.current_frame.scene_builder.insert(
787 &window.current_frame.z_index_stack,
788 path.scale(scale_factor),
789 );
790 }
791
792 /// Paint an underline into the scene for the current frame at the current z-index.
793 pub fn paint_underline(
794 &mut self,
795 origin: Point<Pixels>,
796 width: Pixels,
797 style: &UnderlineStyle,
798 ) -> Result<()> {
799 let scale_factor = self.scale_factor();
800 let height = if style.wavy {
801 style.thickness * 3.
802 } else {
803 style.thickness
804 };
805 let bounds = Bounds {
806 origin,
807 size: size(width, height),
808 };
809 let content_mask = self.content_mask();
810 let window = &mut *self.window;
811 window.current_frame.scene_builder.insert(
812 &window.current_frame.z_index_stack,
813 Underline {
814 order: 0,
815 bounds: bounds.scale(scale_factor),
816 content_mask: content_mask.scale(scale_factor),
817 thickness: style.thickness.scale(scale_factor),
818 color: style.color.unwrap_or_default(),
819 wavy: style.wavy,
820 },
821 );
822 Ok(())
823 }
824
825 /// Paint a monochrome (non-emoji) glyph into the scene for the current frame at the current z-index.
826 /// The y component of the origin is the baseline of the glyph.
827 pub fn paint_glyph(
828 &mut self,
829 origin: Point<Pixels>,
830 font_id: FontId,
831 glyph_id: GlyphId,
832 font_size: Pixels,
833 color: Hsla,
834 ) -> Result<()> {
835 let scale_factor = self.scale_factor();
836 let glyph_origin = origin.scale(scale_factor);
837 let subpixel_variant = Point {
838 x: (glyph_origin.x.0.fract() * SUBPIXEL_VARIANTS as f32).floor() as u8,
839 y: (glyph_origin.y.0.fract() * SUBPIXEL_VARIANTS as f32).floor() as u8,
840 };
841 let params = RenderGlyphParams {
842 font_id,
843 glyph_id,
844 font_size,
845 subpixel_variant,
846 scale_factor,
847 is_emoji: false,
848 };
849
850 let raster_bounds = self.text_system().raster_bounds(¶ms)?;
851 if !raster_bounds.is_zero() {
852 let tile =
853 self.window
854 .sprite_atlas
855 .get_or_insert_with(¶ms.clone().into(), &mut || {
856 let (size, bytes) = self.text_system().rasterize_glyph(¶ms)?;
857 Ok((size, Cow::Owned(bytes)))
858 })?;
859 let bounds = Bounds {
860 origin: glyph_origin.map(|px| px.floor()) + raster_bounds.origin.map(Into::into),
861 size: tile.bounds.size.map(Into::into),
862 };
863 let content_mask = self.content_mask().scale(scale_factor);
864 let window = &mut *self.window;
865 window.current_frame.scene_builder.insert(
866 &window.current_frame.z_index_stack,
867 MonochromeSprite {
868 order: 0,
869 bounds,
870 content_mask,
871 color,
872 tile,
873 },
874 );
875 }
876 Ok(())
877 }
878
879 /// Paint an emoji glyph into the scene for the current frame at the current z-index.
880 /// The y component of the origin is the baseline of the glyph.
881 pub fn paint_emoji(
882 &mut self,
883 origin: Point<Pixels>,
884 font_id: FontId,
885 glyph_id: GlyphId,
886 font_size: Pixels,
887 ) -> Result<()> {
888 let scale_factor = self.scale_factor();
889 let glyph_origin = origin.scale(scale_factor);
890 let params = RenderGlyphParams {
891 font_id,
892 glyph_id,
893 font_size,
894 // We don't render emojis with subpixel variants.
895 subpixel_variant: Default::default(),
896 scale_factor,
897 is_emoji: true,
898 };
899
900 let raster_bounds = self.text_system().raster_bounds(¶ms)?;
901 if !raster_bounds.is_zero() {
902 let tile =
903 self.window
904 .sprite_atlas
905 .get_or_insert_with(¶ms.clone().into(), &mut || {
906 let (size, bytes) = self.text_system().rasterize_glyph(¶ms)?;
907 Ok((size, Cow::Owned(bytes)))
908 })?;
909 let bounds = Bounds {
910 origin: glyph_origin.map(|px| px.floor()) + raster_bounds.origin.map(Into::into),
911 size: tile.bounds.size.map(Into::into),
912 };
913 let content_mask = self.content_mask().scale(scale_factor);
914 let window = &mut *self.window;
915
916 window.current_frame.scene_builder.insert(
917 &window.current_frame.z_index_stack,
918 PolychromeSprite {
919 order: 0,
920 bounds,
921 corner_radii: Default::default(),
922 content_mask,
923 tile,
924 grayscale: false,
925 },
926 );
927 }
928 Ok(())
929 }
930
931 /// Paint a monochrome SVG into the scene for the current frame at the current stacking context.
932 pub fn paint_svg(
933 &mut self,
934 bounds: Bounds<Pixels>,
935 path: SharedString,
936 color: Hsla,
937 ) -> Result<()> {
938 let scale_factor = self.scale_factor();
939 let bounds = bounds.scale(scale_factor);
940 // Render the SVG at twice the size to get a higher quality result.
941 let params = RenderSvgParams {
942 path,
943 size: bounds
944 .size
945 .map(|pixels| DevicePixels::from((pixels.0 * 2.).ceil() as i32)),
946 };
947
948 let tile =
949 self.window
950 .sprite_atlas
951 .get_or_insert_with(¶ms.clone().into(), &mut || {
952 let bytes = self.svg_renderer.render(¶ms)?;
953 Ok((params.size, Cow::Owned(bytes)))
954 })?;
955 let content_mask = self.content_mask().scale(scale_factor);
956
957 let window = &mut *self.window;
958 window.current_frame.scene_builder.insert(
959 &window.current_frame.z_index_stack,
960 MonochromeSprite {
961 order: 0,
962 bounds,
963 content_mask,
964 color,
965 tile,
966 },
967 );
968
969 Ok(())
970 }
971
972 /// Paint an image into the scene for the current frame at the current z-index.
973 pub fn paint_image(
974 &mut self,
975 bounds: Bounds<Pixels>,
976 corner_radii: Corners<Pixels>,
977 data: Arc<ImageData>,
978 grayscale: bool,
979 ) -> Result<()> {
980 let scale_factor = self.scale_factor();
981 let bounds = bounds.scale(scale_factor);
982 let params = RenderImageParams { image_id: data.id };
983
984 let tile = self
985 .window
986 .sprite_atlas
987 .get_or_insert_with(¶ms.clone().into(), &mut || {
988 Ok((data.size(), Cow::Borrowed(data.as_bytes())))
989 })?;
990 let content_mask = self.content_mask().scale(scale_factor);
991 let corner_radii = corner_radii.scale(scale_factor);
992
993 let window = &mut *self.window;
994 window.current_frame.scene_builder.insert(
995 &window.current_frame.z_index_stack,
996 PolychromeSprite {
997 order: 0,
998 bounds,
999 content_mask,
1000 corner_radii,
1001 tile,
1002 grayscale,
1003 },
1004 );
1005 Ok(())
1006 }
1007
1008 /// Draw pixels to the display for this window based on the contents of its scene.
1009 pub(crate) fn draw(&mut self) {
1010 let root_view = self.window.root_view.take().unwrap();
1011
1012 self.start_frame();
1013
1014 self.stack(0, |cx| {
1015 let available_space = cx.window.content_size.map(Into::into);
1016 root_view.draw(available_space, cx);
1017 });
1018
1019 if let Some(active_drag) = self.app.active_drag.take() {
1020 self.stack(1, |cx| {
1021 let offset = cx.mouse_position() - active_drag.cursor_offset;
1022 cx.with_element_offset(Some(offset), |cx| {
1023 let available_space =
1024 size(AvailableSpace::MinContent, AvailableSpace::MinContent);
1025 active_drag.view.draw(available_space, cx);
1026 cx.active_drag = Some(active_drag);
1027 });
1028 });
1029 } else if let Some(active_tooltip) = self.app.active_tooltip.take() {
1030 self.stack(1, |cx| {
1031 cx.with_element_offset(Some(active_tooltip.cursor_offset), |cx| {
1032 let available_space =
1033 size(AvailableSpace::MinContent, AvailableSpace::MinContent);
1034 active_tooltip.view.draw(available_space, cx);
1035 });
1036 });
1037 }
1038
1039 self.window.root_view = Some(root_view);
1040 let scene = self.window.current_frame.scene_builder.build();
1041
1042 self.window.platform_window.draw(scene);
1043 let cursor_style = self
1044 .window
1045 .requested_cursor_style
1046 .take()
1047 .unwrap_or(CursorStyle::Arrow);
1048 self.platform.set_cursor_style(cursor_style);
1049
1050 self.window.dirty = false;
1051 }
1052
1053 /// Rotate the current frame and the previous frame, then clear the current frame.
1054 /// We repopulate all state in the current frame during each paint.
1055 fn start_frame(&mut self) {
1056 self.text_system().start_frame();
1057
1058 let window = &mut *self.window;
1059 mem::swap(&mut window.previous_frame, &mut window.current_frame);
1060 let frame = &mut window.current_frame;
1061 frame.element_states.clear();
1062 frame.key_matchers.clear();
1063 frame.mouse_listeners.values_mut().for_each(Vec::clear);
1064 frame.focus_listeners.clear();
1065 frame.key_dispatch_stack.clear();
1066 frame.focus_parents_by_child.clear();
1067 frame.freeze_key_dispatch_stack = false;
1068 }
1069
1070 /// Dispatch a mouse or keyboard event on the window.
1071 pub fn dispatch_event(&mut self, event: InputEvent) -> bool {
1072 // Handlers may set this to false by calling `stop_propagation`
1073 self.app.propagate_event = true;
1074 self.window.default_prevented = false;
1075
1076 let event = match event {
1077 // Track the mouse position with our own state, since accessing the platform
1078 // API for the mouse position can only occur on the main thread.
1079 InputEvent::MouseMove(mouse_move) => {
1080 self.window.mouse_position = mouse_move.position;
1081 InputEvent::MouseMove(mouse_move)
1082 }
1083 // Translate dragging and dropping of external files from the operating system
1084 // to internal drag and drop events.
1085 InputEvent::FileDrop(file_drop) => match file_drop {
1086 FileDropEvent::Entered { position, files } => {
1087 self.window.mouse_position = position;
1088 if self.active_drag.is_none() {
1089 self.active_drag = Some(AnyDrag {
1090 view: self.build_view(|_| files).into(),
1091 cursor_offset: position,
1092 });
1093 }
1094 InputEvent::MouseDown(MouseDownEvent {
1095 position,
1096 button: MouseButton::Left,
1097 click_count: 1,
1098 modifiers: Modifiers::default(),
1099 })
1100 }
1101 FileDropEvent::Pending { position } => {
1102 self.window.mouse_position = position;
1103 InputEvent::MouseMove(MouseMoveEvent {
1104 position,
1105 pressed_button: Some(MouseButton::Left),
1106 modifiers: Modifiers::default(),
1107 })
1108 }
1109 FileDropEvent::Submit { position } => {
1110 self.window.mouse_position = position;
1111 InputEvent::MouseUp(MouseUpEvent {
1112 button: MouseButton::Left,
1113 position,
1114 modifiers: Modifiers::default(),
1115 click_count: 1,
1116 })
1117 }
1118 FileDropEvent::Exited => InputEvent::MouseUp(MouseUpEvent {
1119 button: MouseButton::Left,
1120 position: Point::default(),
1121 modifiers: Modifiers::default(),
1122 click_count: 1,
1123 }),
1124 },
1125 _ => event,
1126 };
1127
1128 if let Some(any_mouse_event) = event.mouse_event() {
1129 if let Some(mut handlers) = self
1130 .window
1131 .current_frame
1132 .mouse_listeners
1133 .remove(&any_mouse_event.type_id())
1134 {
1135 // Because handlers may add other handlers, we sort every time.
1136 handlers.sort_by(|(a, _), (b, _)| a.cmp(b));
1137
1138 // Capture phase, events bubble from back to front. Handlers for this phase are used for
1139 // special purposes, such as detecting events outside of a given Bounds.
1140 for (_, handler) in &mut handlers {
1141 handler(any_mouse_event, DispatchPhase::Capture, self);
1142 if !self.app.propagate_event {
1143 break;
1144 }
1145 }
1146
1147 // Bubble phase, where most normal handlers do their work.
1148 if self.app.propagate_event {
1149 for (_, handler) in handlers.iter_mut().rev() {
1150 handler(any_mouse_event, DispatchPhase::Bubble, self);
1151 if !self.app.propagate_event {
1152 break;
1153 }
1154 }
1155 }
1156
1157 if self.app.propagate_event
1158 && any_mouse_event.downcast_ref::<MouseUpEvent>().is_some()
1159 {
1160 self.active_drag = None;
1161 }
1162
1163 // Just in case any handlers added new handlers, which is weird, but possible.
1164 handlers.extend(
1165 self.window
1166 .current_frame
1167 .mouse_listeners
1168 .get_mut(&any_mouse_event.type_id())
1169 .into_iter()
1170 .flat_map(|handlers| handlers.drain(..)),
1171 );
1172 self.window
1173 .current_frame
1174 .mouse_listeners
1175 .insert(any_mouse_event.type_id(), handlers);
1176 }
1177 } else if let Some(any_key_event) = event.keyboard_event() {
1178 let key_dispatch_stack = mem::take(&mut self.window.current_frame.key_dispatch_stack);
1179 let key_event_type = any_key_event.type_id();
1180 let mut context_stack = SmallVec::<[&DispatchContext; 16]>::new();
1181
1182 for (ix, frame) in key_dispatch_stack.iter().enumerate() {
1183 match frame {
1184 KeyDispatchStackFrame::Listener {
1185 event_type,
1186 listener,
1187 } => {
1188 if key_event_type == *event_type {
1189 if let Some(action) = listener(
1190 any_key_event,
1191 &context_stack,
1192 DispatchPhase::Capture,
1193 self,
1194 ) {
1195 self.dispatch_action(action, &key_dispatch_stack[..ix]);
1196 }
1197 if !self.app.propagate_event {
1198 break;
1199 }
1200 }
1201 }
1202 KeyDispatchStackFrame::Context(context) => {
1203 context_stack.push(&context);
1204 }
1205 }
1206 }
1207
1208 if self.app.propagate_event {
1209 for (ix, frame) in key_dispatch_stack.iter().enumerate().rev() {
1210 match frame {
1211 KeyDispatchStackFrame::Listener {
1212 event_type,
1213 listener,
1214 } => {
1215 if key_event_type == *event_type {
1216 if let Some(action) = listener(
1217 any_key_event,
1218 &context_stack,
1219 DispatchPhase::Bubble,
1220 self,
1221 ) {
1222 self.dispatch_action(action, &key_dispatch_stack[..ix]);
1223 }
1224
1225 if !self.app.propagate_event {
1226 break;
1227 }
1228 }
1229 }
1230 KeyDispatchStackFrame::Context(_) => {
1231 context_stack.pop();
1232 }
1233 }
1234 }
1235 }
1236
1237 drop(context_stack);
1238 self.window.current_frame.key_dispatch_stack = key_dispatch_stack;
1239 }
1240
1241 !self.app.propagate_event
1242 }
1243
1244 /// Attempt to map a keystroke to an action based on the keymap.
1245 pub fn match_keystroke(
1246 &mut self,
1247 element_id: &GlobalElementId,
1248 keystroke: &Keystroke,
1249 context_stack: &[&DispatchContext],
1250 ) -> KeyMatch {
1251 let key_match = self
1252 .window
1253 .current_frame
1254 .key_matchers
1255 .get_mut(element_id)
1256 .unwrap()
1257 .match_keystroke(keystroke, context_stack);
1258
1259 if key_match.is_some() {
1260 for matcher in self.window.current_frame.key_matchers.values_mut() {
1261 matcher.clear_pending();
1262 }
1263 }
1264
1265 key_match
1266 }
1267
1268 /// Register the given handler to be invoked whenever the global of the given type
1269 /// is updated.
1270 pub fn observe_global<G: 'static>(
1271 &mut self,
1272 f: impl Fn(&mut WindowContext<'_>) + 'static,
1273 ) -> Subscription {
1274 let window_handle = self.window.handle;
1275 self.global_observers.insert(
1276 TypeId::of::<G>(),
1277 Box::new(move |cx| window_handle.update(cx, |_, cx| f(cx)).is_ok()),
1278 )
1279 }
1280
1281 pub fn activate_window(&self) {
1282 self.window.platform_window.activate();
1283 }
1284
1285 pub fn prompt(
1286 &self,
1287 level: PromptLevel,
1288 msg: &str,
1289 answers: &[&str],
1290 ) -> oneshot::Receiver<usize> {
1291 self.window.platform_window.prompt(level, msg, answers)
1292 }
1293
1294 fn dispatch_action(
1295 &mut self,
1296 action: Box<dyn Action>,
1297 dispatch_stack: &[KeyDispatchStackFrame],
1298 ) {
1299 let action_type = action.as_any().type_id();
1300
1301 if let Some(mut global_listeners) = self.app.global_action_listeners.remove(&action_type) {
1302 for listener in &global_listeners {
1303 listener(action.as_ref(), DispatchPhase::Capture, self);
1304 if !self.app.propagate_event {
1305 break;
1306 }
1307 }
1308 global_listeners.extend(
1309 self.global_action_listeners
1310 .remove(&action_type)
1311 .unwrap_or_default(),
1312 );
1313 self.global_action_listeners
1314 .insert(action_type, global_listeners);
1315 }
1316
1317 if self.app.propagate_event {
1318 for stack_frame in dispatch_stack {
1319 if let KeyDispatchStackFrame::Listener {
1320 event_type,
1321 listener,
1322 } = stack_frame
1323 {
1324 if action_type == *event_type {
1325 listener(action.as_any(), &[], DispatchPhase::Capture, self);
1326 if !self.app.propagate_event {
1327 break;
1328 }
1329 }
1330 }
1331 }
1332 }
1333
1334 if self.app.propagate_event {
1335 for stack_frame in dispatch_stack.iter().rev() {
1336 if let KeyDispatchStackFrame::Listener {
1337 event_type,
1338 listener,
1339 } = stack_frame
1340 {
1341 if action_type == *event_type {
1342 self.app.propagate_event = false;
1343 listener(action.as_any(), &[], DispatchPhase::Bubble, self);
1344 if !self.app.propagate_event {
1345 break;
1346 }
1347 }
1348 }
1349 }
1350 }
1351
1352 if self.app.propagate_event {
1353 if let Some(mut global_listeners) =
1354 self.app.global_action_listeners.remove(&action_type)
1355 {
1356 for listener in global_listeners.iter().rev() {
1357 self.app.propagate_event = false;
1358 listener(action.as_ref(), DispatchPhase::Bubble, self);
1359 if !self.app.propagate_event {
1360 break;
1361 }
1362 }
1363 global_listeners.extend(
1364 self.global_action_listeners
1365 .remove(&action_type)
1366 .unwrap_or_default(),
1367 );
1368 self.global_action_listeners
1369 .insert(action_type, global_listeners);
1370 }
1371 }
1372 }
1373}
1374
1375impl Context for WindowContext<'_> {
1376 type Result<T> = T;
1377
1378 fn build_model<T>(
1379 &mut self,
1380 build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
1381 ) -> Model<T>
1382 where
1383 T: 'static,
1384 {
1385 let slot = self.app.entities.reserve();
1386 let model = build_model(&mut ModelContext::new(&mut *self.app, slot.downgrade()));
1387 self.entities.insert(slot, model)
1388 }
1389
1390 fn update_model<T: 'static, R>(
1391 &mut self,
1392 model: &Model<T>,
1393 update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
1394 ) -> R {
1395 let mut entity = self.entities.lease(model);
1396 let result = update(
1397 &mut *entity,
1398 &mut ModelContext::new(&mut *self.app, model.downgrade()),
1399 );
1400 self.entities.end_lease(entity);
1401 result
1402 }
1403
1404 fn update_window<T, F>(&mut self, window: AnyWindowHandle, update: F) -> Result<T>
1405 where
1406 F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
1407 {
1408 if window == self.window.handle {
1409 let root_view = self.window.root_view.clone().unwrap();
1410 Ok(update(root_view, self))
1411 } else {
1412 window.update(self.app, update)
1413 }
1414 }
1415
1416 fn read_model<T, R>(
1417 &self,
1418 handle: &Model<T>,
1419 read: impl FnOnce(&T, &AppContext) -> R,
1420 ) -> Self::Result<R>
1421 where
1422 T: 'static,
1423 {
1424 let entity = self.entities.read(handle);
1425 read(&*entity, &*self.app)
1426 }
1427}
1428
1429impl VisualContext for WindowContext<'_> {
1430 fn build_view<V>(
1431 &mut self,
1432 build_view_state: impl FnOnce(&mut ViewContext<'_, V>) -> V,
1433 ) -> Self::Result<View<V>>
1434 where
1435 V: 'static + Render,
1436 {
1437 let slot = self.app.entities.reserve();
1438 let view = View {
1439 model: slot.clone(),
1440 };
1441 let mut cx = ViewContext::new(&mut *self.app, &mut *self.window, &view);
1442 let entity = build_view_state(&mut cx);
1443 cx.entities.insert(slot, entity);
1444
1445 cx.new_view_observers
1446 .clone()
1447 .retain(&TypeId::of::<V>(), |observer| {
1448 let any_view = AnyView::from(view.clone());
1449 (observer)(any_view, self);
1450 true
1451 });
1452
1453 view
1454 }
1455
1456 /// Update the given view. Prefer calling `View::update` instead, which calls this method.
1457 fn update_view<T: 'static, R>(
1458 &mut self,
1459 view: &View<T>,
1460 update: impl FnOnce(&mut T, &mut ViewContext<'_, T>) -> R,
1461 ) -> Self::Result<R> {
1462 let mut lease = self.app.entities.lease(&view.model);
1463 let mut cx = ViewContext::new(&mut *self.app, &mut *self.window, &view);
1464 let result = update(&mut *lease, &mut cx);
1465 cx.app.entities.end_lease(lease);
1466 result
1467 }
1468
1469 fn replace_root_view<V>(
1470 &mut self,
1471 build_view: impl FnOnce(&mut ViewContext<'_, V>) -> V,
1472 ) -> Self::Result<View<V>>
1473 where
1474 V: Render,
1475 {
1476 let slot = self.app.entities.reserve();
1477 let view = View {
1478 model: slot.clone(),
1479 };
1480 let mut cx = ViewContext::new(&mut *self.app, &mut *self.window, &view);
1481 let entity = build_view(&mut cx);
1482 self.entities.insert(slot, entity);
1483 self.window.root_view = Some(view.clone().into());
1484 view
1485 }
1486}
1487
1488impl<'a> std::ops::Deref for WindowContext<'a> {
1489 type Target = AppContext;
1490
1491 fn deref(&self) -> &Self::Target {
1492 &self.app
1493 }
1494}
1495
1496impl<'a> std::ops::DerefMut for WindowContext<'a> {
1497 fn deref_mut(&mut self) -> &mut Self::Target {
1498 &mut self.app
1499 }
1500}
1501
1502impl<'a> Borrow<AppContext> for WindowContext<'a> {
1503 fn borrow(&self) -> &AppContext {
1504 &self.app
1505 }
1506}
1507
1508impl<'a> BorrowMut<AppContext> for WindowContext<'a> {
1509 fn borrow_mut(&mut self) -> &mut AppContext {
1510 &mut self.app
1511 }
1512}
1513
1514pub trait BorrowWindow: BorrowMut<Window> + BorrowMut<AppContext> {
1515 fn app_mut(&mut self) -> &mut AppContext {
1516 self.borrow_mut()
1517 }
1518
1519 fn window(&self) -> &Window {
1520 self.borrow()
1521 }
1522
1523 fn window_mut(&mut self) -> &mut Window {
1524 self.borrow_mut()
1525 }
1526
1527 /// Pushes the given element id onto the global stack and invokes the given closure
1528 /// with a `GlobalElementId`, which disambiguates the given id in the context of its ancestor
1529 /// ids. Because elements are discarded and recreated on each frame, the `GlobalElementId` is
1530 /// used to associate state with identified elements across separate frames.
1531 fn with_element_id<R>(
1532 &mut self,
1533 id: impl Into<ElementId>,
1534 f: impl FnOnce(GlobalElementId, &mut Self) -> R,
1535 ) -> R {
1536 let keymap = self.app_mut().keymap.clone();
1537 let window = self.window_mut();
1538 window.element_id_stack.push(id.into());
1539 let global_id = window.element_id_stack.clone();
1540
1541 if window.current_frame.key_matchers.get(&global_id).is_none() {
1542 window.current_frame.key_matchers.insert(
1543 global_id.clone(),
1544 window
1545 .previous_frame
1546 .key_matchers
1547 .remove(&global_id)
1548 .unwrap_or_else(|| KeyMatcher::new(keymap)),
1549 );
1550 }
1551
1552 let result = f(global_id, self);
1553 let window: &mut Window = self.borrow_mut();
1554 window.element_id_stack.pop();
1555 result
1556 }
1557
1558 /// Invoke the given function with the given content mask after intersecting it
1559 /// with the current mask.
1560 fn with_content_mask<R>(
1561 &mut self,
1562 mask: ContentMask<Pixels>,
1563 f: impl FnOnce(&mut Self) -> R,
1564 ) -> R {
1565 let mask = mask.intersect(&self.content_mask());
1566 self.window_mut()
1567 .current_frame
1568 .content_mask_stack
1569 .push(mask);
1570 let result = f(self);
1571 self.window_mut().current_frame.content_mask_stack.pop();
1572 result
1573 }
1574
1575 /// Update the global element offset based on the given offset. This is used to implement
1576 /// scrolling and position drag handles.
1577 fn with_element_offset<R>(
1578 &mut self,
1579 offset: Option<Point<Pixels>>,
1580 f: impl FnOnce(&mut Self) -> R,
1581 ) -> R {
1582 let Some(offset) = offset else {
1583 return f(self);
1584 };
1585
1586 let offset = self.element_offset() + offset;
1587 self.window_mut()
1588 .current_frame
1589 .element_offset_stack
1590 .push(offset);
1591 let result = f(self);
1592 self.window_mut().current_frame.element_offset_stack.pop();
1593 result
1594 }
1595
1596 /// Obtain the current element offset.
1597 fn element_offset(&self) -> Point<Pixels> {
1598 self.window()
1599 .current_frame
1600 .element_offset_stack
1601 .last()
1602 .copied()
1603 .unwrap_or_default()
1604 }
1605
1606 /// Update or intialize state for an element with the given id that lives across multiple
1607 /// frames. If an element with this id existed in the previous frame, its state will be passed
1608 /// to the given closure. The state returned by the closure will be stored so it can be referenced
1609 /// when drawing the next frame.
1610 fn with_element_state<S, R>(
1611 &mut self,
1612 id: ElementId,
1613 f: impl FnOnce(Option<S>, &mut Self) -> (R, S),
1614 ) -> R
1615 where
1616 S: 'static,
1617 {
1618 self.with_element_id(id, |global_id, cx| {
1619 if let Some(any) = cx
1620 .window_mut()
1621 .current_frame
1622 .element_states
1623 .remove(&global_id)
1624 .or_else(|| {
1625 cx.window_mut()
1626 .previous_frame
1627 .element_states
1628 .remove(&global_id)
1629 })
1630 {
1631 // Using the extra inner option to avoid needing to reallocate a new box.
1632 let mut state_box = any
1633 .downcast::<Option<S>>()
1634 .expect("invalid element state type for id");
1635 let state = state_box
1636 .take()
1637 .expect("element state is already on the stack");
1638 let (result, state) = f(Some(state), cx);
1639 state_box.replace(state);
1640 cx.window_mut()
1641 .current_frame
1642 .element_states
1643 .insert(global_id, state_box);
1644 result
1645 } else {
1646 let (result, state) = f(None, cx);
1647 cx.window_mut()
1648 .current_frame
1649 .element_states
1650 .insert(global_id, Box::new(Some(state)));
1651 result
1652 }
1653 })
1654 }
1655
1656 /// Like `with_element_state`, but for situations where the element_id is optional. If the
1657 /// id is `None`, no state will be retrieved or stored.
1658 fn with_optional_element_state<S, R>(
1659 &mut self,
1660 element_id: Option<ElementId>,
1661 f: impl FnOnce(Option<S>, &mut Self) -> (R, S),
1662 ) -> R
1663 where
1664 S: 'static,
1665 {
1666 if let Some(element_id) = element_id {
1667 self.with_element_state(element_id, f)
1668 } else {
1669 f(None, self).0
1670 }
1671 }
1672
1673 /// Obtain the current content mask.
1674 fn content_mask(&self) -> ContentMask<Pixels> {
1675 self.window()
1676 .current_frame
1677 .content_mask_stack
1678 .last()
1679 .cloned()
1680 .unwrap_or_else(|| ContentMask {
1681 bounds: Bounds {
1682 origin: Point::default(),
1683 size: self.window().content_size,
1684 },
1685 })
1686 }
1687
1688 /// The size of an em for the base font of the application. Adjusting this value allows the
1689 /// UI to scale, just like zooming a web page.
1690 fn rem_size(&self) -> Pixels {
1691 self.window().rem_size
1692 }
1693}
1694
1695impl Borrow<Window> for WindowContext<'_> {
1696 fn borrow(&self) -> &Window {
1697 &self.window
1698 }
1699}
1700
1701impl BorrowMut<Window> for WindowContext<'_> {
1702 fn borrow_mut(&mut self) -> &mut Window {
1703 &mut self.window
1704 }
1705}
1706
1707impl<T> BorrowWindow for T where T: BorrowMut<AppContext> + BorrowMut<Window> {}
1708
1709pub struct ViewContext<'a, V> {
1710 window_cx: WindowContext<'a>,
1711 view: &'a View<V>,
1712}
1713
1714impl<V> Borrow<AppContext> for ViewContext<'_, V> {
1715 fn borrow(&self) -> &AppContext {
1716 &*self.window_cx.app
1717 }
1718}
1719
1720impl<V> BorrowMut<AppContext> for ViewContext<'_, V> {
1721 fn borrow_mut(&mut self) -> &mut AppContext {
1722 &mut *self.window_cx.app
1723 }
1724}
1725
1726impl<V> Borrow<Window> for ViewContext<'_, V> {
1727 fn borrow(&self) -> &Window {
1728 &*self.window_cx.window
1729 }
1730}
1731
1732impl<V> BorrowMut<Window> for ViewContext<'_, V> {
1733 fn borrow_mut(&mut self) -> &mut Window {
1734 &mut *self.window_cx.window
1735 }
1736}
1737
1738impl<'a, V: 'static> ViewContext<'a, V> {
1739 pub(crate) fn new(app: &'a mut AppContext, window: &'a mut Window, view: &'a View<V>) -> Self {
1740 Self {
1741 window_cx: WindowContext::new(app, window),
1742 view,
1743 }
1744 }
1745
1746 // todo!("change this to return a reference");
1747 pub fn view(&self) -> View<V> {
1748 self.view.clone()
1749 }
1750
1751 pub fn model(&self) -> Model<V> {
1752 self.view.model.clone()
1753 }
1754
1755 /// Access the underlying window context.
1756 pub fn window_context(&mut self) -> &mut WindowContext<'a> {
1757 &mut self.window_cx
1758 }
1759
1760 pub fn with_z_index<R>(&mut self, z_index: u32, f: impl FnOnce(&mut Self) -> R) -> R {
1761 self.window.current_frame.z_index_stack.push(z_index);
1762 let result = f(self);
1763 self.window.current_frame.z_index_stack.pop();
1764 result
1765 }
1766
1767 pub fn on_next_frame(&mut self, f: impl FnOnce(&mut V, &mut ViewContext<V>) + 'static)
1768 where
1769 V: 'static,
1770 {
1771 let view = self.view();
1772 self.window_cx.on_next_frame(move |cx| view.update(cx, f));
1773 }
1774
1775 /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
1776 /// that are currently on the stack to be returned to the app.
1777 pub fn defer(&mut self, f: impl FnOnce(&mut V, &mut ViewContext<V>) + 'static) {
1778 let view = self.view().downgrade();
1779 self.window_cx.defer(move |cx| {
1780 view.update(cx, f).ok();
1781 });
1782 }
1783
1784 pub fn observe<V2, E>(
1785 &mut self,
1786 entity: &E,
1787 mut on_notify: impl FnMut(&mut V, E, &mut ViewContext<'_, V>) + 'static,
1788 ) -> Subscription
1789 where
1790 V2: 'static,
1791 V: 'static,
1792 E: Entity<V2>,
1793 {
1794 let view = self.view().downgrade();
1795 let entity_id = entity.entity_id();
1796 let entity = entity.downgrade();
1797 let window_handle = self.window.handle;
1798 self.app.observers.insert(
1799 entity_id,
1800 Box::new(move |cx| {
1801 window_handle
1802 .update(cx, |_, cx| {
1803 if let Some(handle) = E::upgrade_from(&entity) {
1804 view.update(cx, |this, cx| on_notify(this, handle, cx))
1805 .is_ok()
1806 } else {
1807 false
1808 }
1809 })
1810 .unwrap_or(false)
1811 }),
1812 )
1813 }
1814
1815 pub fn subscribe<V2, E>(
1816 &mut self,
1817 entity: &E,
1818 mut on_event: impl FnMut(&mut V, E, &V2::Event, &mut ViewContext<'_, V>) + 'static,
1819 ) -> Subscription
1820 where
1821 V2: EventEmitter,
1822 E: Entity<V2>,
1823 {
1824 let view = self.view().downgrade();
1825 let entity_id = entity.entity_id();
1826 let handle = entity.downgrade();
1827 let window_handle = self.window.handle;
1828 self.app.event_listeners.insert(
1829 entity_id,
1830 Box::new(move |event, cx| {
1831 window_handle
1832 .update(cx, |_, cx| {
1833 if let Some(handle) = E::upgrade_from(&handle) {
1834 let event = event.downcast_ref().expect("invalid event type");
1835 view.update(cx, |this, cx| on_event(this, handle, event, cx))
1836 .is_ok()
1837 } else {
1838 false
1839 }
1840 })
1841 .unwrap_or(false)
1842 }),
1843 )
1844 }
1845
1846 pub fn on_release(
1847 &mut self,
1848 on_release: impl FnOnce(&mut V, &mut WindowContext) + 'static,
1849 ) -> Subscription {
1850 let window_handle = self.window.handle;
1851 self.app.release_listeners.insert(
1852 self.view.model.entity_id,
1853 Box::new(move |this, cx| {
1854 let this = this.downcast_mut().expect("invalid entity type");
1855 let _ = window_handle.update(cx, |_, cx| on_release(this, cx));
1856 }),
1857 )
1858 }
1859
1860 pub fn observe_release<V2, E>(
1861 &mut self,
1862 entity: &E,
1863 mut on_release: impl FnMut(&mut V, &mut V2, &mut ViewContext<'_, V>) + 'static,
1864 ) -> Subscription
1865 where
1866 V: 'static,
1867 V2: 'static,
1868 E: Entity<V2>,
1869 {
1870 let view = self.view().downgrade();
1871 let entity_id = entity.entity_id();
1872 let window_handle = self.window.handle;
1873 self.app.release_listeners.insert(
1874 entity_id,
1875 Box::new(move |entity, cx| {
1876 let entity = entity.downcast_mut().expect("invalid entity type");
1877 let _ = window_handle.update(cx, |_, cx| {
1878 view.update(cx, |this, cx| on_release(this, entity, cx))
1879 });
1880 }),
1881 )
1882 }
1883
1884 pub fn notify(&mut self) {
1885 self.window_cx.notify();
1886 self.window_cx.app.push_effect(Effect::Notify {
1887 emitter: self.view.model.entity_id,
1888 });
1889 }
1890
1891 pub fn observe_window_bounds(
1892 &mut self,
1893 mut callback: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
1894 ) -> Subscription {
1895 let view = self.view.downgrade();
1896 self.window.bounds_observers.insert(
1897 (),
1898 Box::new(move |cx| view.update(cx, |view, cx| callback(view, cx)).is_ok()),
1899 )
1900 }
1901
1902 pub fn observe_window_activation(
1903 &mut self,
1904 mut callback: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
1905 ) -> Subscription {
1906 let view = self.view.downgrade();
1907 self.window.activation_observers.insert(
1908 (),
1909 Box::new(move |cx| view.update(cx, |view, cx| callback(view, cx)).is_ok()),
1910 )
1911 }
1912
1913 /// Register a listener to be called when the given focus handle receives focus.
1914 /// Unlike [on_focus_changed], returns a subscription and persists until the subscription
1915 /// is dropped.
1916 pub fn on_focus(
1917 &mut self,
1918 handle: &FocusHandle,
1919 mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
1920 ) -> Subscription {
1921 let view = self.view.downgrade();
1922 let focus_id = handle.id;
1923 self.window.focus_listeners.insert(
1924 (),
1925 Box::new(move |event, cx| {
1926 view.update(cx, |view, cx| {
1927 if event.focused.as_ref().map(|focused| focused.id) == Some(focus_id) {
1928 listener(view, cx)
1929 }
1930 })
1931 .is_ok()
1932 }),
1933 )
1934 }
1935
1936 /// Register a listener to be called when the given focus handle or one of its descendants receives focus.
1937 /// Unlike [on_focus_changed], returns a subscription and persists until the subscription
1938 /// is dropped.
1939 pub fn on_focus_in(
1940 &mut self,
1941 handle: &FocusHandle,
1942 mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
1943 ) -> Subscription {
1944 let view = self.view.downgrade();
1945 let focus_id = handle.id;
1946 self.window.focus_listeners.insert(
1947 (),
1948 Box::new(move |event, cx| {
1949 view.update(cx, |view, cx| {
1950 if event
1951 .focused
1952 .as_ref()
1953 .map_or(false, |focused| focus_id.contains(focused.id, cx))
1954 {
1955 listener(view, cx)
1956 }
1957 })
1958 .is_ok()
1959 }),
1960 )
1961 }
1962
1963 /// Register a listener to be called when the given focus handle loses focus.
1964 /// Unlike [on_focus_changed], returns a subscription and persists until the subscription
1965 /// is dropped.
1966 pub fn on_blur(
1967 &mut self,
1968 handle: &FocusHandle,
1969 mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
1970 ) -> Subscription {
1971 let view = self.view.downgrade();
1972 let focus_id = handle.id;
1973 self.window.focus_listeners.insert(
1974 (),
1975 Box::new(move |event, cx| {
1976 view.update(cx, |view, cx| {
1977 if event.blurred.as_ref().map(|blurred| blurred.id) == Some(focus_id) {
1978 listener(view, cx)
1979 }
1980 })
1981 .is_ok()
1982 }),
1983 )
1984 }
1985
1986 /// Register a listener to be called when the given focus handle or one of its descendants loses focus.
1987 /// Unlike [on_focus_changed], returns a subscription and persists until the subscription
1988 /// is dropped.
1989 pub fn on_focus_out(
1990 &mut self,
1991 handle: &FocusHandle,
1992 mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
1993 ) -> Subscription {
1994 let view = self.view.downgrade();
1995 let focus_id = handle.id;
1996 self.window.focus_listeners.insert(
1997 (),
1998 Box::new(move |event, cx| {
1999 view.update(cx, |view, cx| {
2000 if event
2001 .blurred
2002 .as_ref()
2003 .map_or(false, |blurred| focus_id.contains(blurred.id, cx))
2004 {
2005 listener(view, cx)
2006 }
2007 })
2008 .is_ok()
2009 }),
2010 )
2011 }
2012
2013 /// Register a focus listener for the current frame only. It will be cleared
2014 /// on the next frame render. You should use this method only from within elements,
2015 /// and we may want to enforce that better via a different context type.
2016 // todo!() Move this to `FrameContext` to emphasize its individuality?
2017 pub fn on_focus_changed(
2018 &mut self,
2019 listener: impl Fn(&mut V, &FocusEvent, &mut ViewContext<V>) + 'static,
2020 ) {
2021 let handle = self.view().downgrade();
2022 self.window
2023 .current_frame
2024 .focus_listeners
2025 .push(Box::new(move |event, cx| {
2026 handle
2027 .update(cx, |view, cx| listener(view, event, cx))
2028 .log_err();
2029 }));
2030 }
2031
2032 pub fn with_key_listeners<R>(
2033 &mut self,
2034 key_listeners: impl IntoIterator<Item = (TypeId, KeyListener<V>)>,
2035 f: impl FnOnce(&mut Self) -> R,
2036 ) -> R {
2037 let old_stack_len = self.window.current_frame.key_dispatch_stack.len();
2038 if !self.window.current_frame.freeze_key_dispatch_stack {
2039 for (event_type, listener) in key_listeners {
2040 let handle = self.view().downgrade();
2041 let listener = Box::new(
2042 move |event: &dyn Any,
2043 context_stack: &[&DispatchContext],
2044 phase: DispatchPhase,
2045 cx: &mut WindowContext<'_>| {
2046 handle
2047 .update(cx, |view, cx| {
2048 listener(view, event, context_stack, phase, cx)
2049 })
2050 .log_err()
2051 .flatten()
2052 },
2053 );
2054 self.window.current_frame.key_dispatch_stack.push(
2055 KeyDispatchStackFrame::Listener {
2056 event_type,
2057 listener,
2058 },
2059 );
2060 }
2061 }
2062
2063 let result = f(self);
2064
2065 if !self.window.current_frame.freeze_key_dispatch_stack {
2066 self.window
2067 .current_frame
2068 .key_dispatch_stack
2069 .truncate(old_stack_len);
2070 }
2071
2072 result
2073 }
2074
2075 pub fn with_key_dispatch_context<R>(
2076 &mut self,
2077 context: DispatchContext,
2078 f: impl FnOnce(&mut Self) -> R,
2079 ) -> R {
2080 if context.is_empty() {
2081 return f(self);
2082 }
2083
2084 if !self.window.current_frame.freeze_key_dispatch_stack {
2085 self.window
2086 .current_frame
2087 .key_dispatch_stack
2088 .push(KeyDispatchStackFrame::Context(context));
2089 }
2090
2091 let result = f(self);
2092
2093 if !self.window.previous_frame.freeze_key_dispatch_stack {
2094 self.window.previous_frame.key_dispatch_stack.pop();
2095 }
2096
2097 result
2098 }
2099
2100 pub fn with_focus<R>(
2101 &mut self,
2102 focus_handle: FocusHandle,
2103 f: impl FnOnce(&mut Self) -> R,
2104 ) -> R {
2105 if let Some(parent_focus_id) = self.window.current_frame.focus_stack.last().copied() {
2106 self.window
2107 .current_frame
2108 .focus_parents_by_child
2109 .insert(focus_handle.id, parent_focus_id);
2110 }
2111 self.window.current_frame.focus_stack.push(focus_handle.id);
2112
2113 if Some(focus_handle.id) == self.window.focus {
2114 self.window.current_frame.freeze_key_dispatch_stack = true;
2115 }
2116
2117 let result = f(self);
2118
2119 self.window.current_frame.focus_stack.pop();
2120 result
2121 }
2122
2123 pub fn spawn<Fut, R>(
2124 &mut self,
2125 f: impl FnOnce(WeakView<V>, AsyncWindowContext) -> Fut,
2126 ) -> Task<R>
2127 where
2128 R: 'static,
2129 Fut: Future<Output = R> + 'static,
2130 {
2131 let view = self.view().downgrade();
2132 self.window_cx.spawn(|cx| f(view, cx))
2133 }
2134
2135 pub fn update_global<G, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R
2136 where
2137 G: 'static,
2138 {
2139 let mut global = self.app.lease_global::<G>();
2140 let result = f(&mut global, self);
2141 self.app.end_global_lease(global);
2142 result
2143 }
2144
2145 pub fn observe_global<G: 'static>(
2146 &mut self,
2147 f: impl Fn(&mut V, &mut ViewContext<'_, V>) + 'static,
2148 ) -> Subscription {
2149 let window_handle = self.window.handle;
2150 let view = self.view().downgrade();
2151 self.global_observers.insert(
2152 TypeId::of::<G>(),
2153 Box::new(move |cx| {
2154 window_handle
2155 .update(cx, |_, cx| view.update(cx, |view, cx| f(view, cx)).is_ok())
2156 .unwrap_or(false)
2157 }),
2158 )
2159 }
2160
2161 pub fn on_mouse_event<Event: 'static>(
2162 &mut self,
2163 handler: impl Fn(&mut V, &Event, DispatchPhase, &mut ViewContext<V>) + 'static,
2164 ) {
2165 let handle = self.view();
2166 self.window_cx.on_mouse_event(move |event, phase, cx| {
2167 handle.update(cx, |view, cx| {
2168 handler(view, event, phase, cx);
2169 })
2170 });
2171 }
2172
2173 /// Set an input handler, such as [ElementInputHandler], which interfaces with the
2174 /// platform to receive textual input with proper integration with concerns such
2175 /// as IME interactions.
2176 pub fn handle_input(
2177 &mut self,
2178 focus_handle: &FocusHandle,
2179 input_handler: impl PlatformInputHandler,
2180 ) {
2181 if focus_handle.is_focused(self) {
2182 self.window
2183 .platform_window
2184 .set_input_handler(Box::new(input_handler));
2185 }
2186 }
2187}
2188
2189impl<V> ViewContext<'_, V>
2190where
2191 V: EventEmitter,
2192 V::Event: 'static,
2193{
2194 pub fn emit(&mut self, event: V::Event) {
2195 let emitter = self.view.model.entity_id;
2196 self.app.push_effect(Effect::Emit {
2197 emitter,
2198 event: Box::new(event),
2199 });
2200 }
2201}
2202
2203impl<V> Context for ViewContext<'_, V> {
2204 type Result<U> = U;
2205
2206 fn build_model<T: 'static>(
2207 &mut self,
2208 build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
2209 ) -> Model<T> {
2210 self.window_cx.build_model(build_model)
2211 }
2212
2213 fn update_model<T: 'static, R>(
2214 &mut self,
2215 model: &Model<T>,
2216 update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
2217 ) -> R {
2218 self.window_cx.update_model(model, update)
2219 }
2220
2221 fn update_window<T, F>(&mut self, window: AnyWindowHandle, update: F) -> Result<T>
2222 where
2223 F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
2224 {
2225 self.window_cx.update_window(window, update)
2226 }
2227
2228 fn read_model<T, R>(
2229 &self,
2230 handle: &Model<T>,
2231 read: impl FnOnce(&T, &AppContext) -> R,
2232 ) -> Self::Result<R>
2233 where
2234 T: 'static,
2235 {
2236 self.window_cx.read_model(handle, read)
2237 }
2238}
2239
2240impl<V: 'static> VisualContext for ViewContext<'_, V> {
2241 fn build_view<W: Render + 'static>(
2242 &mut self,
2243 build_view_state: impl FnOnce(&mut ViewContext<'_, W>) -> W,
2244 ) -> Self::Result<View<W>> {
2245 self.window_cx.build_view(build_view_state)
2246 }
2247
2248 fn update_view<V2: 'static, R>(
2249 &mut self,
2250 view: &View<V2>,
2251 update: impl FnOnce(&mut V2, &mut ViewContext<'_, V2>) -> R,
2252 ) -> Self::Result<R> {
2253 self.window_cx.update_view(view, update)
2254 }
2255
2256 fn replace_root_view<W>(
2257 &mut self,
2258 build_view: impl FnOnce(&mut ViewContext<'_, W>) -> W,
2259 ) -> Self::Result<View<W>>
2260 where
2261 W: Render,
2262 {
2263 self.window_cx.replace_root_view(build_view)
2264 }
2265}
2266
2267impl<'a, V> std::ops::Deref for ViewContext<'a, V> {
2268 type Target = WindowContext<'a>;
2269
2270 fn deref(&self) -> &Self::Target {
2271 &self.window_cx
2272 }
2273}
2274
2275impl<'a, V> std::ops::DerefMut for ViewContext<'a, V> {
2276 fn deref_mut(&mut self) -> &mut Self::Target {
2277 &mut self.window_cx
2278 }
2279}
2280
2281// #[derive(Clone, Copy, Eq, PartialEq, Hash)]
2282slotmap::new_key_type! { pub struct WindowId; }
2283
2284impl WindowId {
2285 pub fn as_u64(&self) -> u64 {
2286 self.0.as_ffi()
2287 }
2288}
2289
2290#[derive(Deref, DerefMut)]
2291pub struct WindowHandle<V> {
2292 #[deref]
2293 #[deref_mut]
2294 pub(crate) any_handle: AnyWindowHandle,
2295 state_type: PhantomData<V>,
2296}
2297
2298impl<V: 'static + Render> WindowHandle<V> {
2299 pub fn new(id: WindowId) -> Self {
2300 WindowHandle {
2301 any_handle: AnyWindowHandle {
2302 id,
2303 state_type: TypeId::of::<V>(),
2304 },
2305 state_type: PhantomData,
2306 }
2307 }
2308
2309 pub fn update<C, R>(
2310 self,
2311 cx: &mut C,
2312 update: impl FnOnce(&mut V, &mut ViewContext<'_, V>) -> R,
2313 ) -> Result<R>
2314 where
2315 C: Context,
2316 {
2317 cx.update_window(self.any_handle, |root_view, cx| {
2318 let view = root_view
2319 .downcast::<V>()
2320 .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
2321 Ok(cx.update_view(&view, update))
2322 })?
2323 }
2324}
2325
2326impl<V> Copy for WindowHandle<V> {}
2327
2328impl<V> Clone for WindowHandle<V> {
2329 fn clone(&self) -> Self {
2330 WindowHandle {
2331 any_handle: self.any_handle,
2332 state_type: PhantomData,
2333 }
2334 }
2335}
2336
2337impl<V> PartialEq for WindowHandle<V> {
2338 fn eq(&self, other: &Self) -> bool {
2339 self.any_handle == other.any_handle
2340 }
2341}
2342
2343impl<V> Eq for WindowHandle<V> {}
2344
2345impl<V> Hash for WindowHandle<V> {
2346 fn hash<H: Hasher>(&self, state: &mut H) {
2347 self.any_handle.hash(state);
2348 }
2349}
2350
2351impl<V: 'static> Into<AnyWindowHandle> for WindowHandle<V> {
2352 fn into(self) -> AnyWindowHandle {
2353 self.any_handle
2354 }
2355}
2356
2357#[derive(Copy, Clone, PartialEq, Eq, Hash)]
2358pub struct AnyWindowHandle {
2359 pub(crate) id: WindowId,
2360 state_type: TypeId,
2361}
2362
2363impl AnyWindowHandle {
2364 pub fn window_id(&self) -> WindowId {
2365 self.id
2366 }
2367
2368 pub fn downcast<T: 'static>(&self) -> Option<WindowHandle<T>> {
2369 if TypeId::of::<T>() == self.state_type {
2370 Some(WindowHandle {
2371 any_handle: *self,
2372 state_type: PhantomData,
2373 })
2374 } else {
2375 None
2376 }
2377 }
2378
2379 pub fn update<C, R>(
2380 self,
2381 cx: &mut C,
2382 update: impl FnOnce(AnyView, &mut WindowContext<'_>) -> R,
2383 ) -> Result<R>
2384 where
2385 C: Context,
2386 {
2387 cx.update_window(self, update)
2388 }
2389}
2390
2391#[cfg(any(test, feature = "test-support"))]
2392impl From<SmallVec<[u32; 16]>> for StackingOrder {
2393 fn from(small_vec: SmallVec<[u32; 16]>) -> Self {
2394 StackingOrder(small_vec)
2395 }
2396}
2397
2398#[derive(Clone, Debug, Eq, PartialEq, Hash)]
2399pub enum ElementId {
2400 View(EntityId),
2401 Number(usize),
2402 Name(SharedString),
2403 FocusHandle(FocusId),
2404}
2405
2406impl From<EntityId> for ElementId {
2407 fn from(id: EntityId) -> Self {
2408 ElementId::View(id)
2409 }
2410}
2411
2412impl From<usize> for ElementId {
2413 fn from(id: usize) -> Self {
2414 ElementId::Number(id)
2415 }
2416}
2417
2418impl From<i32> for ElementId {
2419 fn from(id: i32) -> Self {
2420 Self::Number(id as usize)
2421 }
2422}
2423
2424impl From<SharedString> for ElementId {
2425 fn from(name: SharedString) -> Self {
2426 ElementId::Name(name)
2427 }
2428}
2429
2430impl From<&'static str> for ElementId {
2431 fn from(name: &'static str) -> Self {
2432 ElementId::Name(name.into())
2433 }
2434}
2435
2436impl<'a> From<&'a FocusHandle> for ElementId {
2437 fn from(handle: &'a FocusHandle) -> Self {
2438 ElementId::FocusHandle(handle.id)
2439 }
2440}