1use crate::{
2 px, size, transparent_black, Action, AnyDrag, AnyView, AppContext, Arena, AsyncWindowContext,
3 AvailableSpace, Bounds, Context, Corners, CursorStyle, DispatchActionListener, DispatchNodeId,
4 DispatchTree, DisplayId, Edges, Effect, Entity, EntityId, EventEmitter, FileDropEvent, Flatten,
5 GlobalElementId, Hsla, KeyBinding, KeyContext, KeyDownEvent, KeyMatch, KeymatchResult,
6 Keystroke, KeystrokeEvent, Model, ModelContext, Modifiers, MouseButton, MouseMoveEvent,
7 MouseUpEvent, Pixels, PlatformAtlas, PlatformDisplay, PlatformInput, PlatformWindow, Point,
8 PromptLevel, Render, ScaledPixels, SharedString, Size, SubscriberSet, Subscription,
9 TaffyLayoutEngine, Task, View, VisualContext, WeakView, WindowBounds, WindowOptions,
10};
11use anyhow::{anyhow, Context as _, Result};
12use collections::FxHashSet;
13use derive_more::{Deref, DerefMut};
14use futures::{
15 channel::{mpsc, oneshot},
16 StreamExt,
17};
18use parking_lot::RwLock;
19use slotmap::SlotMap;
20use smallvec::SmallVec;
21use std::{
22 any::{Any, TypeId},
23 borrow::{Borrow, BorrowMut},
24 cell::RefCell,
25 collections::hash_map::Entry,
26 fmt::{Debug, Display},
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 time::Duration,
37};
38use util::{measure, ResultExt};
39
40mod element_cx;
41pub use element_cx::*;
42
43const ACTIVE_DRAG_Z_INDEX: u16 = 1;
44
45/// A global stacking order, which is created by stacking successive z-index values.
46/// Each z-index will always be interpreted in the context of its parent z-index.
47#[derive(Debug, Deref, DerefMut, Clone, Ord, PartialOrd, PartialEq, Eq, Default)]
48pub struct StackingOrder(SmallVec<[StackingContext; 64]>);
49
50/// A single entry in a primitive's z-index stacking order
51#[derive(Clone, Ord, PartialOrd, PartialEq, Eq, Default)]
52pub struct StackingContext {
53 pub(crate) z_index: u16,
54 pub(crate) id: u16,
55}
56
57impl std::fmt::Debug for StackingContext {
58 fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
59 write!(f, "{{{}.{}}} ", self.z_index, self.id)
60 }
61}
62
63/// Represents the two different phases when dispatching events.
64#[derive(Default, Copy, Clone, Debug, Eq, PartialEq)]
65pub enum DispatchPhase {
66 /// After the capture phase comes the bubble phase, in which mouse event listeners are
67 /// invoked front to back and keyboard event listeners are invoked from the focused element
68 /// to the root of the element tree. This is the phase you'll most commonly want to use when
69 /// registering event listeners.
70 #[default]
71 Bubble,
72 /// During the initial capture phase, mouse event listeners are invoked back to front, and keyboard
73 /// listeners are invoked from the root of the tree downward toward the focused element. This phase
74 /// is used for special purposes such as clearing the "pressed" state for click events. If
75 /// you stop event propagation during this phase, you need to know what you're doing. Handlers
76 /// outside of the immediate region may rely on detecting non-local events during this phase.
77 Capture,
78}
79
80impl DispatchPhase {
81 /// Returns true if this represents the "bubble" phase.
82 pub fn bubble(self) -> bool {
83 self == DispatchPhase::Bubble
84 }
85
86 /// Returns true if this represents the "capture" phase.
87 pub fn capture(self) -> bool {
88 self == DispatchPhase::Capture
89 }
90}
91
92type AnyObserver = Box<dyn FnMut(&mut WindowContext) -> bool + 'static>;
93
94type AnyWindowFocusListener = Box<dyn FnMut(&FocusEvent, &mut WindowContext) -> bool + 'static>;
95
96struct FocusEvent {
97 previous_focus_path: SmallVec<[FocusId; 8]>,
98 current_focus_path: SmallVec<[FocusId; 8]>,
99}
100
101slotmap::new_key_type! {
102 /// A globally unique identifier for a focusable element.
103 pub struct FocusId;
104}
105
106thread_local! {
107 pub(crate) static ELEMENT_ARENA: RefCell<Arena> = RefCell::new(Arena::new(4 * 1024 * 1024));
108}
109
110impl FocusId {
111 /// Obtains whether the element associated with this handle is currently focused.
112 pub fn is_focused(&self, cx: &WindowContext) -> bool {
113 cx.window.focus == Some(*self)
114 }
115
116 /// Obtains whether the element associated with this handle contains the focused
117 /// element or is itself focused.
118 pub fn contains_focused(&self, cx: &WindowContext) -> bool {
119 cx.focused()
120 .map_or(false, |focused| self.contains(focused.id, cx))
121 }
122
123 /// Obtains whether the element associated with this handle is contained within the
124 /// focused element or is itself focused.
125 pub fn within_focused(&self, cx: &WindowContext) -> bool {
126 let focused = cx.focused();
127 focused.map_or(false, |focused| focused.id.contains(*self, cx))
128 }
129
130 /// Obtains whether this handle contains the given handle in the most recently rendered frame.
131 pub(crate) fn contains(&self, other: Self, cx: &WindowContext) -> bool {
132 cx.window
133 .rendered_frame
134 .dispatch_tree
135 .focus_contains(*self, other)
136 }
137}
138
139/// A handle which can be used to track and manipulate the focused element in a window.
140pub struct FocusHandle {
141 pub(crate) id: FocusId,
142 handles: Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>,
143}
144
145impl std::fmt::Debug for FocusHandle {
146 fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
147 f.write_fmt(format_args!("FocusHandle({:?})", self.id))
148 }
149}
150
151impl FocusHandle {
152 pub(crate) fn new(handles: &Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>) -> Self {
153 let id = handles.write().insert(AtomicUsize::new(1));
154 Self {
155 id,
156 handles: handles.clone(),
157 }
158 }
159
160 pub(crate) fn for_id(
161 id: FocusId,
162 handles: &Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>,
163 ) -> Option<Self> {
164 let lock = handles.read();
165 let ref_count = lock.get(id)?;
166 if ref_count.load(SeqCst) == 0 {
167 None
168 } else {
169 ref_count.fetch_add(1, SeqCst);
170 Some(Self {
171 id,
172 handles: handles.clone(),
173 })
174 }
175 }
176
177 /// Moves the focus to the element associated with this handle.
178 pub fn focus(&self, cx: &mut WindowContext) {
179 cx.focus(self)
180 }
181
182 /// Obtains whether the element associated with this handle is currently focused.
183 pub fn is_focused(&self, cx: &WindowContext) -> bool {
184 self.id.is_focused(cx)
185 }
186
187 /// Obtains whether the element associated with this handle contains the focused
188 /// element or is itself focused.
189 pub fn contains_focused(&self, cx: &WindowContext) -> bool {
190 self.id.contains_focused(cx)
191 }
192
193 /// Obtains whether the element associated with this handle is contained within the
194 /// focused element or is itself focused.
195 pub fn within_focused(&self, cx: &WindowContext) -> bool {
196 self.id.within_focused(cx)
197 }
198
199 /// Obtains whether this handle contains the given handle in the most recently rendered frame.
200 pub fn contains(&self, other: &Self, cx: &WindowContext) -> bool {
201 self.id.contains(other.id, cx)
202 }
203}
204
205impl Clone for FocusHandle {
206 fn clone(&self) -> Self {
207 Self::for_id(self.id, &self.handles).unwrap()
208 }
209}
210
211impl PartialEq for FocusHandle {
212 fn eq(&self, other: &Self) -> bool {
213 self.id == other.id
214 }
215}
216
217impl Eq for FocusHandle {}
218
219impl Drop for FocusHandle {
220 fn drop(&mut self) {
221 self.handles
222 .read()
223 .get(self.id)
224 .unwrap()
225 .fetch_sub(1, SeqCst);
226 }
227}
228
229/// FocusableView allows users of your view to easily
230/// focus it (using cx.focus_view(view))
231pub trait FocusableView: 'static + Render {
232 /// Returns the focus handle associated with this view.
233 fn focus_handle(&self, cx: &AppContext) -> FocusHandle;
234}
235
236/// ManagedView is a view (like a Modal, Popover, Menu, etc.)
237/// where the lifecycle of the view is handled by another view.
238pub trait ManagedView: FocusableView + EventEmitter<DismissEvent> {}
239
240impl<M: FocusableView + EventEmitter<DismissEvent>> ManagedView for M {}
241
242/// Emitted by implementers of [`ManagedView`] to indicate the view should be dismissed, such as when a view is presented as a modal.
243pub struct DismissEvent;
244
245// Holds the state for a specific window.
246#[doc(hidden)]
247pub struct Window {
248 pub(crate) handle: AnyWindowHandle,
249 pub(crate) removed: bool,
250 pub(crate) platform_window: Box<dyn PlatformWindow>,
251 display_id: DisplayId,
252 sprite_atlas: Arc<dyn PlatformAtlas>,
253 pub(crate) rem_size: Pixels,
254 pub(crate) viewport_size: Size<Pixels>,
255 layout_engine: Option<TaffyLayoutEngine>,
256 pub(crate) root_view: Option<AnyView>,
257 pub(crate) element_id_stack: GlobalElementId,
258 pub(crate) rendered_frame: Frame,
259 pub(crate) next_frame: Frame,
260 pub(crate) dirty_views: FxHashSet<EntityId>,
261 pub(crate) focus_handles: Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>,
262 focus_listeners: SubscriberSet<(), AnyWindowFocusListener>,
263 focus_lost_listeners: SubscriberSet<(), AnyObserver>,
264 default_prevented: bool,
265 mouse_position: Point<Pixels>,
266 modifiers: Modifiers,
267 scale_factor: f32,
268 bounds: WindowBounds,
269 bounds_observers: SubscriberSet<(), AnyObserver>,
270 active: bool,
271 pub(crate) dirty: bool,
272 pub(crate) refreshing: bool,
273 pub(crate) drawing: bool,
274 activation_observers: SubscriberSet<(), AnyObserver>,
275 pub(crate) focus: Option<FocusId>,
276 focus_enabled: bool,
277 pending_input: Option<PendingInput>,
278
279 #[cfg(any(test, feature = "test-support"))]
280 pub(crate) focus_invalidated: bool,
281}
282
283#[derive(Default, Debug)]
284struct PendingInput {
285 keystrokes: SmallVec<[Keystroke; 1]>,
286 bindings: SmallVec<[KeyBinding; 1]>,
287 focus: Option<FocusId>,
288 timer: Option<Task<()>>,
289}
290
291impl PendingInput {
292 fn is_noop(&self) -> bool {
293 self.bindings.is_empty() && (self.keystrokes.iter().all(|k| k.ime_key.is_none()))
294 }
295
296 fn input(&self) -> String {
297 self.keystrokes
298 .iter()
299 .flat_map(|k| k.ime_key.clone())
300 .collect::<Vec<String>>()
301 .join("")
302 }
303
304 fn used_by_binding(&self, binding: &KeyBinding) -> bool {
305 if self.keystrokes.is_empty() {
306 return true;
307 }
308 let keystroke = &self.keystrokes[0];
309 for candidate in keystroke.match_candidates() {
310 if binding.match_keystrokes(&[candidate]) == KeyMatch::Pending {
311 return true;
312 }
313 }
314 false
315 }
316}
317
318pub(crate) struct ElementStateBox {
319 pub(crate) inner: Box<dyn Any>,
320 pub(crate) parent_view_id: EntityId,
321 #[cfg(debug_assertions)]
322 pub(crate) type_name: &'static str,
323}
324
325impl Window {
326 pub(crate) fn new(
327 handle: AnyWindowHandle,
328 options: WindowOptions,
329 cx: &mut AppContext,
330 ) -> Self {
331 let platform_window = cx.platform.open_window(handle, options);
332 let display_id = platform_window.display().id();
333 let sprite_atlas = platform_window.sprite_atlas();
334 let mouse_position = platform_window.mouse_position();
335 let modifiers = platform_window.modifiers();
336 let content_size = platform_window.content_size();
337 let scale_factor = platform_window.scale_factor();
338 let bounds = platform_window.bounds();
339
340 platform_window.on_request_frame(Box::new({
341 let mut cx = cx.to_async();
342 move || {
343 measure("frame duration", || {
344 handle.update(&mut cx, |_, cx| cx.draw()).log_err();
345 })
346 }
347 }));
348 platform_window.on_resize(Box::new({
349 let mut cx = cx.to_async();
350 move |_, _| {
351 handle
352 .update(&mut cx, |_, cx| cx.window_bounds_changed())
353 .log_err();
354 }
355 }));
356 platform_window.on_moved(Box::new({
357 let mut cx = cx.to_async();
358 move || {
359 handle
360 .update(&mut cx, |_, cx| cx.window_bounds_changed())
361 .log_err();
362 }
363 }));
364 platform_window.on_active_status_change(Box::new({
365 let mut cx = cx.to_async();
366 move |active| {
367 handle
368 .update(&mut cx, |_, cx| {
369 cx.window.active = active;
370 cx.window
371 .activation_observers
372 .clone()
373 .retain(&(), |callback| callback(cx));
374 })
375 .log_err();
376 }
377 }));
378
379 platform_window.on_input({
380 let mut cx = cx.to_async();
381 Box::new(move |event| {
382 handle
383 .update(&mut cx, |_, cx| cx.dispatch_event(event))
384 .log_err()
385 .unwrap_or(false)
386 })
387 });
388
389 Window {
390 handle,
391 removed: false,
392 platform_window,
393 display_id,
394 sprite_atlas,
395 rem_size: px(16.),
396 viewport_size: content_size,
397 layout_engine: Some(TaffyLayoutEngine::new()),
398 root_view: None,
399 element_id_stack: GlobalElementId::default(),
400 rendered_frame: Frame::new(DispatchTree::new(cx.keymap.clone(), cx.actions.clone())),
401 next_frame: Frame::new(DispatchTree::new(cx.keymap.clone(), cx.actions.clone())),
402 dirty_views: FxHashSet::default(),
403 focus_handles: Arc::new(RwLock::new(SlotMap::with_key())),
404 focus_listeners: SubscriberSet::new(),
405 focus_lost_listeners: SubscriberSet::new(),
406 default_prevented: true,
407 mouse_position,
408 modifiers,
409 scale_factor,
410 bounds,
411 bounds_observers: SubscriberSet::new(),
412 active: false,
413 dirty: false,
414 refreshing: false,
415 drawing: false,
416 activation_observers: SubscriberSet::new(),
417 focus: None,
418 focus_enabled: true,
419 pending_input: None,
420
421 #[cfg(any(test, feature = "test-support"))]
422 focus_invalidated: false,
423 }
424 }
425}
426
427/// Indicates which region of the window is visible. Content falling outside of this mask will not be
428/// rendered. Currently, only rectangular content masks are supported, but we give the mask its own type
429/// to leave room to support more complex shapes in the future.
430#[derive(Clone, Debug, Default, PartialEq, Eq)]
431#[repr(C)]
432pub struct ContentMask<P: Clone + Default + Debug> {
433 /// The bounds
434 pub bounds: Bounds<P>,
435}
436
437impl ContentMask<Pixels> {
438 /// Scale the content mask's pixel units by the given scaling factor.
439 pub fn scale(&self, factor: f32) -> ContentMask<ScaledPixels> {
440 ContentMask {
441 bounds: self.bounds.scale(factor),
442 }
443 }
444
445 /// Intersect the content mask with the given content mask.
446 pub fn intersect(&self, other: &Self) -> Self {
447 let bounds = self.bounds.intersect(&other.bounds);
448 ContentMask { bounds }
449 }
450}
451
452/// Provides access to application state in the context of a single window. Derefs
453/// to an [`AppContext`], so you can also pass a [`WindowContext`] to any method that takes
454/// an [`AppContext`] and call any [`AppContext`] methods.
455pub struct WindowContext<'a> {
456 pub(crate) app: &'a mut AppContext,
457 pub(crate) window: &'a mut Window,
458}
459
460impl<'a> WindowContext<'a> {
461 pub(crate) fn new(app: &'a mut AppContext, window: &'a mut Window) -> Self {
462 Self { app, window }
463 }
464
465 /// Obtain a handle to the window that belongs to this context.
466 pub fn window_handle(&self) -> AnyWindowHandle {
467 self.window.handle
468 }
469
470 /// Mark the window as dirty, scheduling it to be redrawn on the next frame.
471 pub fn refresh(&mut self) {
472 if !self.window.drawing {
473 self.window.refreshing = true;
474 self.window.dirty = true;
475 }
476 }
477
478 /// Close this window.
479 pub fn remove_window(&mut self) {
480 self.window.removed = true;
481 }
482
483 /// Obtain a new [`FocusHandle`], which allows you to track and manipulate the keyboard focus
484 /// for elements rendered within this window.
485 pub fn focus_handle(&mut self) -> FocusHandle {
486 FocusHandle::new(&self.window.focus_handles)
487 }
488
489 /// Obtain the currently focused [`FocusHandle`]. If no elements are focused, returns `None`.
490 pub fn focused(&self) -> Option<FocusHandle> {
491 self.window
492 .focus
493 .and_then(|id| FocusHandle::for_id(id, &self.window.focus_handles))
494 }
495
496 /// Move focus to the element associated with the given [`FocusHandle`].
497 pub fn focus(&mut self, handle: &FocusHandle) {
498 if !self.window.focus_enabled || self.window.focus == Some(handle.id) {
499 return;
500 }
501
502 self.window.focus = Some(handle.id);
503 self.window
504 .rendered_frame
505 .dispatch_tree
506 .clear_pending_keystrokes();
507
508 #[cfg(any(test, feature = "test-support"))]
509 {
510 self.window.focus_invalidated = true;
511 }
512
513 self.refresh();
514 }
515
516 /// Remove focus from all elements within this context's window.
517 pub fn blur(&mut self) {
518 if !self.window.focus_enabled {
519 return;
520 }
521
522 self.window.focus = None;
523 self.refresh();
524 }
525
526 /// Blur the window and don't allow anything in it to be focused again.
527 pub fn disable_focus(&mut self) {
528 self.blur();
529 self.window.focus_enabled = false;
530 }
531
532 /// Dispatch the given action on the currently focused element.
533 pub fn dispatch_action(&mut self, action: Box<dyn Action>) {
534 let focus_handle = self.focused();
535
536 self.defer(move |cx| {
537 let node_id = focus_handle
538 .and_then(|handle| {
539 cx.window
540 .rendered_frame
541 .dispatch_tree
542 .focusable_node_id(handle.id)
543 })
544 .unwrap_or_else(|| cx.window.rendered_frame.dispatch_tree.root_node_id());
545
546 cx.propagate_event = true;
547 cx.dispatch_action_on_node(node_id, action);
548 })
549 }
550
551 pub(crate) fn dispatch_keystroke_observers(
552 &mut self,
553 event: &dyn Any,
554 action: Option<Box<dyn Action>>,
555 ) {
556 let Some(key_down_event) = event.downcast_ref::<KeyDownEvent>() else {
557 return;
558 };
559
560 self.keystroke_observers
561 .clone()
562 .retain(&(), move |callback| {
563 (callback)(
564 &KeystrokeEvent {
565 keystroke: key_down_event.keystroke.clone(),
566 action: action.as_ref().map(|action| action.boxed_clone()),
567 },
568 self,
569 );
570 true
571 });
572 }
573
574 pub(crate) fn clear_pending_keystrokes(&mut self) {
575 self.window
576 .rendered_frame
577 .dispatch_tree
578 .clear_pending_keystrokes();
579 self.window
580 .next_frame
581 .dispatch_tree
582 .clear_pending_keystrokes();
583 }
584
585 /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
586 /// that are currently on the stack to be returned to the app.
587 pub fn defer(&mut self, f: impl FnOnce(&mut WindowContext) + 'static) {
588 let handle = self.window.handle;
589 self.app.defer(move |cx| {
590 handle.update(cx, |_, cx| f(cx)).ok();
591 });
592 }
593
594 /// Subscribe to events emitted by a model or view.
595 /// The entity to which you're subscribing must implement the [`EventEmitter`] trait.
596 /// The callback will be invoked a handle to the emitting entity (either a [`View`] or [`Model`]), the event, and a window context for the current window.
597 pub fn subscribe<Emitter, E, Evt>(
598 &mut self,
599 entity: &E,
600 mut on_event: impl FnMut(E, &Evt, &mut WindowContext<'_>) + 'static,
601 ) -> Subscription
602 where
603 Emitter: EventEmitter<Evt>,
604 E: Entity<Emitter>,
605 Evt: 'static,
606 {
607 let entity_id = entity.entity_id();
608 let entity = entity.downgrade();
609 let window_handle = self.window.handle;
610 let (subscription, activate) = self.app.event_listeners.insert(
611 entity_id,
612 (
613 TypeId::of::<Evt>(),
614 Box::new(move |event, cx| {
615 window_handle
616 .update(cx, |_, cx| {
617 if let Some(handle) = E::upgrade_from(&entity) {
618 let event = event.downcast_ref().expect("invalid event type");
619 on_event(handle, event, cx);
620 true
621 } else {
622 false
623 }
624 })
625 .unwrap_or(false)
626 }),
627 ),
628 );
629 self.app.defer(move |_| activate());
630 subscription
631 }
632
633 /// Creates an [`AsyncWindowContext`], which has a static lifetime and can be held across
634 /// await points in async code.
635 pub fn to_async(&self) -> AsyncWindowContext {
636 AsyncWindowContext::new(self.app.to_async(), self.window.handle)
637 }
638
639 /// Schedule the given closure to be run directly after the current frame is rendered.
640 pub fn on_next_frame(&mut self, callback: impl FnOnce(&mut WindowContext) + 'static) {
641 let handle = self.window.handle;
642 let display_id = self.window.display_id;
643
644 let mut frame_consumers = std::mem::take(&mut self.app.frame_consumers);
645 if let Entry::Vacant(e) = frame_consumers.entry(display_id) {
646 let (tx, mut rx) = mpsc::unbounded::<()>();
647 self.platform.set_display_link_output_callback(
648 display_id,
649 Box::new(move || _ = tx.unbounded_send(())),
650 );
651
652 let consumer_task = self.app.spawn(|cx| async move {
653 while rx.next().await.is_some() {
654 cx.update(|cx| {
655 for callback in cx
656 .next_frame_callbacks
657 .get_mut(&display_id)
658 .unwrap()
659 .drain(..)
660 .collect::<SmallVec<[_; 32]>>()
661 {
662 callback(cx);
663 }
664 })
665 .ok();
666
667 // Flush effects, then stop the display link if no new next_frame_callbacks have been added.
668
669 cx.update(|cx| {
670 if cx.next_frame_callbacks.is_empty() {
671 cx.platform.stop_display_link(display_id);
672 }
673 })
674 .ok();
675 }
676 });
677 e.insert(consumer_task);
678 }
679 debug_assert!(self.app.frame_consumers.is_empty());
680 self.app.frame_consumers = frame_consumers;
681
682 if self.next_frame_callbacks.is_empty() {
683 self.platform.start_display_link(display_id);
684 }
685
686 self.next_frame_callbacks
687 .entry(display_id)
688 .or_default()
689 .push(Box::new(move |cx: &mut AppContext| {
690 cx.update_window(handle, |_root_view, cx| callback(cx)).ok();
691 }));
692 }
693
694 /// Spawn the future returned by the given closure on the application thread pool.
695 /// The closure is provided a handle to the current window and an `AsyncWindowContext` for
696 /// use within your future.
697 pub fn spawn<Fut, R>(&mut self, f: impl FnOnce(AsyncWindowContext) -> Fut) -> Task<R>
698 where
699 R: 'static,
700 Fut: Future<Output = R> + 'static,
701 {
702 self.app
703 .spawn(|app| f(AsyncWindowContext::new(app, self.window.handle)))
704 }
705
706 /// Updates the global of the given type. The given closure is given simultaneous mutable
707 /// access both to the global and the context.
708 pub fn update_global<G, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R
709 where
710 G: 'static,
711 {
712 let mut global = self.app.lease_global::<G>();
713 let result = f(&mut global, self);
714 self.app.end_global_lease(global);
715 result
716 }
717
718 fn window_bounds_changed(&mut self) {
719 self.window.scale_factor = self.window.platform_window.scale_factor();
720 self.window.viewport_size = self.window.platform_window.content_size();
721 self.window.bounds = self.window.platform_window.bounds();
722 self.window.display_id = self.window.platform_window.display().id();
723 self.refresh();
724
725 self.window
726 .bounds_observers
727 .clone()
728 .retain(&(), |callback| callback(self));
729 }
730
731 /// Returns the bounds of the current window in the global coordinate space, which could span across multiple displays.
732 pub fn window_bounds(&self) -> WindowBounds {
733 self.window.bounds
734 }
735
736 /// Returns the size of the drawable area within the window.
737 pub fn viewport_size(&self) -> Size<Pixels> {
738 self.window.viewport_size
739 }
740
741 /// Returns whether this window is focused by the operating system (receiving key events).
742 pub fn is_window_active(&self) -> bool {
743 self.window.active
744 }
745
746 /// Toggle zoom on the window.
747 pub fn zoom_window(&self) {
748 self.window.platform_window.zoom();
749 }
750
751 /// Updates the window's title at the platform level.
752 pub fn set_window_title(&mut self, title: &str) {
753 self.window.platform_window.set_title(title);
754 }
755
756 /// Mark the window as dirty at the platform level.
757 pub fn set_window_edited(&mut self, edited: bool) {
758 self.window.platform_window.set_edited(edited);
759 }
760
761 /// Determine the display on which the window is visible.
762 pub fn display(&self) -> Option<Rc<dyn PlatformDisplay>> {
763 self.platform
764 .displays()
765 .into_iter()
766 .find(|display| display.id() == self.window.display_id)
767 }
768
769 /// Show the platform character palette.
770 pub fn show_character_palette(&self) {
771 self.window.platform_window.show_character_palette();
772 }
773
774 /// The scale factor of the display associated with the window. For example, it could
775 /// return 2.0 for a "retina" display, indicating that each logical pixel should actually
776 /// be rendered as two pixels on screen.
777 pub fn scale_factor(&self) -> f32 {
778 self.window.scale_factor
779 }
780
781 /// The size of an em for the base font of the application. Adjusting this value allows the
782 /// UI to scale, just like zooming a web page.
783 pub fn rem_size(&self) -> Pixels {
784 self.window.rem_size
785 }
786
787 /// Sets the size of an em for the base font of the application. Adjusting this value allows the
788 /// UI to scale, just like zooming a web page.
789 pub fn set_rem_size(&mut self, rem_size: impl Into<Pixels>) {
790 self.window.rem_size = rem_size.into();
791 }
792
793 /// The line height associated with the current text style.
794 pub fn line_height(&self) -> Pixels {
795 let rem_size = self.rem_size();
796 let text_style = self.text_style();
797 text_style
798 .line_height
799 .to_pixels(text_style.font_size, rem_size)
800 }
801
802 /// Call to prevent the default action of an event. Currently only used to prevent
803 /// parent elements from becoming focused on mouse down.
804 pub fn prevent_default(&mut self) {
805 self.window.default_prevented = true;
806 }
807
808 /// Obtain whether default has been prevented for the event currently being dispatched.
809 pub fn default_prevented(&self) -> bool {
810 self.window.default_prevented
811 }
812
813 /// Determine whether the given action is available along the dispatch path to the currently focused element.
814 pub fn is_action_available(&self, action: &dyn Action) -> bool {
815 let target = self
816 .focused()
817 .and_then(|focused_handle| {
818 self.window
819 .rendered_frame
820 .dispatch_tree
821 .focusable_node_id(focused_handle.id)
822 })
823 .unwrap_or_else(|| self.window.rendered_frame.dispatch_tree.root_node_id());
824 self.window
825 .rendered_frame
826 .dispatch_tree
827 .is_action_available(action, target)
828 }
829
830 /// The position of the mouse relative to the window.
831 pub fn mouse_position(&self) -> Point<Pixels> {
832 self.window.mouse_position
833 }
834
835 /// The current state of the keyboard's modifiers
836 pub fn modifiers(&self) -> Modifiers {
837 self.window.modifiers
838 }
839
840 /// Returns true if there is no opaque layer containing the given point
841 /// on top of the given level. Layers who are extensions of the queried layer
842 /// are not considered to be on top of queried layer.
843 pub fn was_top_layer(&self, point: &Point<Pixels>, layer: &StackingOrder) -> bool {
844 // Precondition: the depth map is ordered from topmost to bottomost.
845
846 for (opaque_layer, _, bounds) in self.window.rendered_frame.depth_map.iter() {
847 if layer >= opaque_layer {
848 // The queried layer is either above or is the same as the this opaque layer.
849 // Anything after this point is guaranteed to be below the queried layer.
850 return true;
851 }
852
853 if !bounds.contains(point) {
854 // This opaque layer is above the queried layer but it doesn't contain
855 // the given position, so we can ignore it even if it's above.
856 continue;
857 }
858
859 // At this point, we've established that this opaque layer is on top of the queried layer
860 // and contains the position:
861 // - If the opaque layer is an extension of the queried layer, we don't want
862 // to consider the opaque layer to be on top and so we ignore it.
863 // - Else, we will bail early and say that the queried layer wasn't the top one.
864 let opaque_layer_is_extension_of_queried_layer = opaque_layer.len() >= layer.len()
865 && opaque_layer
866 .iter()
867 .zip(layer.iter())
868 .all(|(a, b)| a.z_index == b.z_index);
869 if !opaque_layer_is_extension_of_queried_layer {
870 return false;
871 }
872 }
873
874 true
875 }
876
877 pub(crate) fn was_top_layer_under_active_drag(
878 &self,
879 point: &Point<Pixels>,
880 layer: &StackingOrder,
881 ) -> bool {
882 // Precondition: the depth map is ordered from topmost to bottomost.
883
884 for (opaque_layer, _, bounds) in self.window.rendered_frame.depth_map.iter() {
885 if layer >= opaque_layer {
886 // The queried layer is either above or is the same as the this opaque layer.
887 // Anything after this point is guaranteed to be below the queried layer.
888 return true;
889 }
890
891 if !bounds.contains(point) {
892 // This opaque layer is above the queried layer but it doesn't contain
893 // the given position, so we can ignore it even if it's above.
894 continue;
895 }
896
897 // All normal content is rendered with a base z-index of 0, we know that if the root of this opaque layer
898 // equals `ACTIVE_DRAG_Z_INDEX` then it must be the drag layer and we can ignore it as we are
899 // looking to see if the queried layer was the topmost underneath the drag layer.
900 if opaque_layer
901 .first()
902 .map(|c| c.z_index == ACTIVE_DRAG_Z_INDEX)
903 .unwrap_or(false)
904 {
905 continue;
906 }
907
908 // At this point, we've established that this opaque layer is on top of the queried layer
909 // and contains the position:
910 // - If the opaque layer is an extension of the queried layer, we don't want
911 // to consider the opaque layer to be on top and so we ignore it.
912 // - Else, we will bail early and say that the queried layer wasn't the top one.
913 let opaque_layer_is_extension_of_queried_layer = opaque_layer.len() >= layer.len()
914 && opaque_layer
915 .iter()
916 .zip(layer.iter())
917 .all(|(a, b)| a.z_index == b.z_index);
918 if !opaque_layer_is_extension_of_queried_layer {
919 return false;
920 }
921 }
922
923 true
924 }
925
926 /// Called during painting to get the current stacking order.
927 pub fn stacking_order(&self) -> &StackingOrder {
928 &self.window.next_frame.z_index_stack
929 }
930
931 /// Draw pixels to the display for this window based on the contents of its scene.
932 pub(crate) fn draw(&mut self) {
933 self.window.dirty = false;
934 self.window.drawing = true;
935
936 #[cfg(any(test, feature = "test-support"))]
937 {
938 self.window.focus_invalidated = false;
939 }
940
941 if let Some(requested_handler) = self.window.rendered_frame.requested_input_handler.as_mut()
942 {
943 let input_handler = self.window.platform_window.take_input_handler();
944 requested_handler.handler = input_handler;
945 }
946
947 let root_view = self.window.root_view.take().unwrap();
948 self.with_element_context(|cx| {
949 cx.with_z_index(0, |cx| {
950 cx.with_key_dispatch(Some(KeyContext::default()), None, |_, cx| {
951 // We need to use cx.cx here so we can utilize borrow splitting
952 for (action_type, action_listeners) in &cx.cx.app.global_action_listeners {
953 for action_listener in action_listeners.iter().cloned() {
954 cx.cx.window.next_frame.dispatch_tree.on_action(
955 *action_type,
956 Rc::new(
957 move |action: &dyn Any, phase, cx: &mut WindowContext<'_>| {
958 action_listener(action, phase, cx)
959 },
960 ),
961 )
962 }
963 }
964
965 let available_space = cx.window.viewport_size.map(Into::into);
966 root_view.draw(Point::default(), available_space, cx);
967 })
968 })
969 });
970
971 if let Some(active_drag) = self.app.active_drag.take() {
972 self.with_element_context(|cx| {
973 cx.with_z_index(ACTIVE_DRAG_Z_INDEX, |cx| {
974 let offset = cx.mouse_position() - active_drag.cursor_offset;
975 let available_space =
976 size(AvailableSpace::MinContent, AvailableSpace::MinContent);
977 active_drag.view.draw(offset, available_space, cx);
978 })
979 });
980 self.active_drag = Some(active_drag);
981 } else if let Some(tooltip_request) = self.window.next_frame.tooltip_request.take() {
982 self.with_element_context(|cx| {
983 cx.with_z_index(1, |cx| {
984 let available_space =
985 size(AvailableSpace::MinContent, AvailableSpace::MinContent);
986 tooltip_request.tooltip.view.draw(
987 tooltip_request.tooltip.cursor_offset,
988 available_space,
989 cx,
990 );
991 })
992 });
993 self.window.next_frame.tooltip_request = Some(tooltip_request);
994 }
995 self.window.dirty_views.clear();
996
997 self.window
998 .next_frame
999 .dispatch_tree
1000 .preserve_pending_keystrokes(
1001 &mut self.window.rendered_frame.dispatch_tree,
1002 self.window.focus,
1003 );
1004 self.window.next_frame.focus = self.window.focus;
1005 self.window.next_frame.window_active = self.window.active;
1006 self.window.root_view = Some(root_view);
1007
1008 // Set the cursor only if we're the active window.
1009 let cursor_style = self
1010 .window
1011 .next_frame
1012 .requested_cursor_style
1013 .take()
1014 .unwrap_or(CursorStyle::Arrow);
1015 if self.is_window_active() {
1016 self.platform.set_cursor_style(cursor_style);
1017 }
1018
1019 // Register requested input handler with the platform window.
1020 if let Some(requested_input) = self.window.next_frame.requested_input_handler.as_mut() {
1021 if let Some(handler) = requested_input.handler.take() {
1022 self.window.platform_window.set_input_handler(handler);
1023 }
1024 }
1025
1026 self.window.layout_engine.as_mut().unwrap().clear();
1027 self.text_system()
1028 .finish_frame(&self.window.next_frame.reused_views);
1029 self.window
1030 .next_frame
1031 .finish(&mut self.window.rendered_frame);
1032 ELEMENT_ARENA.with_borrow_mut(|element_arena| element_arena.clear());
1033
1034 let previous_focus_path = self.window.rendered_frame.focus_path();
1035 let previous_window_active = self.window.rendered_frame.window_active;
1036 mem::swap(&mut self.window.rendered_frame, &mut self.window.next_frame);
1037 self.window.next_frame.clear();
1038 let current_focus_path = self.window.rendered_frame.focus_path();
1039 let current_window_active = self.window.rendered_frame.window_active;
1040
1041 if previous_focus_path != current_focus_path
1042 || previous_window_active != current_window_active
1043 {
1044 if !previous_focus_path.is_empty() && current_focus_path.is_empty() {
1045 self.window
1046 .focus_lost_listeners
1047 .clone()
1048 .retain(&(), |listener| listener(self));
1049 }
1050
1051 let event = FocusEvent {
1052 previous_focus_path: if previous_window_active {
1053 previous_focus_path
1054 } else {
1055 Default::default()
1056 },
1057 current_focus_path: if current_window_active {
1058 current_focus_path
1059 } else {
1060 Default::default()
1061 },
1062 };
1063 self.window
1064 .focus_listeners
1065 .clone()
1066 .retain(&(), |listener| listener(&event, self));
1067 }
1068
1069 self.window
1070 .platform_window
1071 .draw(&self.window.rendered_frame.scene);
1072 self.window.refreshing = false;
1073 self.window.drawing = false;
1074 }
1075
1076 /// Dispatch a mouse or keyboard event on the window.
1077 pub fn dispatch_event(&mut self, event: PlatformInput) -> bool {
1078 // Handlers may set this to false by calling `stop_propagation`.
1079 self.app.propagate_event = true;
1080 // Handlers may set this to true by calling `prevent_default`.
1081 self.window.default_prevented = false;
1082
1083 let event = match event {
1084 // Track the mouse position with our own state, since accessing the platform
1085 // API for the mouse position can only occur on the main thread.
1086 PlatformInput::MouseMove(mouse_move) => {
1087 self.window.mouse_position = mouse_move.position;
1088 self.window.modifiers = mouse_move.modifiers;
1089 PlatformInput::MouseMove(mouse_move)
1090 }
1091 PlatformInput::MouseDown(mouse_down) => {
1092 self.window.mouse_position = mouse_down.position;
1093 self.window.modifiers = mouse_down.modifiers;
1094 PlatformInput::MouseDown(mouse_down)
1095 }
1096 PlatformInput::MouseUp(mouse_up) => {
1097 self.window.mouse_position = mouse_up.position;
1098 self.window.modifiers = mouse_up.modifiers;
1099 PlatformInput::MouseUp(mouse_up)
1100 }
1101 PlatformInput::MouseExited(mouse_exited) => {
1102 self.window.modifiers = mouse_exited.modifiers;
1103 PlatformInput::MouseExited(mouse_exited)
1104 }
1105 PlatformInput::ModifiersChanged(modifiers_changed) => {
1106 self.window.modifiers = modifiers_changed.modifiers;
1107 PlatformInput::ModifiersChanged(modifiers_changed)
1108 }
1109 PlatformInput::ScrollWheel(scroll_wheel) => {
1110 self.window.mouse_position = scroll_wheel.position;
1111 self.window.modifiers = scroll_wheel.modifiers;
1112 PlatformInput::ScrollWheel(scroll_wheel)
1113 }
1114 // Translate dragging and dropping of external files from the operating system
1115 // to internal drag and drop events.
1116 PlatformInput::FileDrop(file_drop) => match file_drop {
1117 FileDropEvent::Entered { position, paths } => {
1118 self.window.mouse_position = position;
1119 if self.active_drag.is_none() {
1120 self.active_drag = Some(AnyDrag {
1121 value: Box::new(paths.clone()),
1122 view: self.new_view(|_| paths).into(),
1123 cursor_offset: position,
1124 });
1125 }
1126 PlatformInput::MouseMove(MouseMoveEvent {
1127 position,
1128 pressed_button: Some(MouseButton::Left),
1129 modifiers: Modifiers::default(),
1130 })
1131 }
1132 FileDropEvent::Pending { position } => {
1133 self.window.mouse_position = position;
1134 PlatformInput::MouseMove(MouseMoveEvent {
1135 position,
1136 pressed_button: Some(MouseButton::Left),
1137 modifiers: Modifiers::default(),
1138 })
1139 }
1140 FileDropEvent::Submit { position } => {
1141 self.activate(true);
1142 self.window.mouse_position = position;
1143 PlatformInput::MouseUp(MouseUpEvent {
1144 button: MouseButton::Left,
1145 position,
1146 modifiers: Modifiers::default(),
1147 click_count: 1,
1148 })
1149 }
1150 FileDropEvent::Exited => PlatformInput::MouseUp(MouseUpEvent {
1151 button: MouseButton::Left,
1152 position: Point::default(),
1153 modifiers: Modifiers::default(),
1154 click_count: 1,
1155 }),
1156 },
1157 PlatformInput::KeyDown(_) | PlatformInput::KeyUp(_) => event,
1158 };
1159
1160 if let Some(any_mouse_event) = event.mouse_event() {
1161 self.dispatch_mouse_event(any_mouse_event);
1162 } else if let Some(any_key_event) = event.keyboard_event() {
1163 self.dispatch_key_event(any_key_event);
1164 }
1165
1166 !self.app.propagate_event
1167 }
1168
1169 fn dispatch_mouse_event(&mut self, event: &dyn Any) {
1170 if let Some(mut handlers) = self
1171 .window
1172 .rendered_frame
1173 .mouse_listeners
1174 .remove(&event.type_id())
1175 {
1176 // Because handlers may add other handlers, we sort every time.
1177 handlers.sort_by(|(a, _, _), (b, _, _)| a.cmp(b));
1178
1179 // Capture phase, events bubble from back to front. Handlers for this phase are used for
1180 // special purposes, such as detecting events outside of a given Bounds.
1181 for (_, _, handler) in &mut handlers {
1182 self.with_element_context(|cx| {
1183 handler(event, DispatchPhase::Capture, cx);
1184 });
1185 if !self.app.propagate_event {
1186 break;
1187 }
1188 }
1189
1190 // Bubble phase, where most normal handlers do their work.
1191 if self.app.propagate_event {
1192 for (_, _, handler) in handlers.iter_mut().rev() {
1193 self.with_element_context(|cx| {
1194 handler(event, DispatchPhase::Bubble, cx);
1195 });
1196 if !self.app.propagate_event {
1197 break;
1198 }
1199 }
1200 }
1201
1202 self.window
1203 .rendered_frame
1204 .mouse_listeners
1205 .insert(event.type_id(), handlers);
1206 }
1207
1208 if self.app.propagate_event && self.has_active_drag() {
1209 if event.is::<MouseMoveEvent>() {
1210 // If this was a mouse move event, redraw the window so that the
1211 // active drag can follow the mouse cursor.
1212 self.refresh();
1213 } else if event.is::<MouseUpEvent>() {
1214 // If this was a mouse up event, cancel the active drag and redraw
1215 // the window.
1216 self.active_drag = None;
1217 self.refresh();
1218 }
1219 }
1220 }
1221
1222 fn dispatch_key_event(&mut self, event: &dyn Any) {
1223 let node_id = self
1224 .window
1225 .focus
1226 .and_then(|focus_id| {
1227 self.window
1228 .rendered_frame
1229 .dispatch_tree
1230 .focusable_node_id(focus_id)
1231 })
1232 .unwrap_or_else(|| self.window.rendered_frame.dispatch_tree.root_node_id());
1233
1234 let dispatch_path = self
1235 .window
1236 .rendered_frame
1237 .dispatch_tree
1238 .dispatch_path(node_id);
1239
1240 if let Some(key_down_event) = event.downcast_ref::<KeyDownEvent>() {
1241 let KeymatchResult { bindings, pending } = self
1242 .window
1243 .rendered_frame
1244 .dispatch_tree
1245 .dispatch_key(&key_down_event.keystroke, &dispatch_path);
1246
1247 if pending {
1248 let mut currently_pending = self.window.pending_input.take().unwrap_or_default();
1249 if currently_pending.focus.is_some() && currently_pending.focus != self.window.focus
1250 {
1251 currently_pending = PendingInput::default();
1252 }
1253 currently_pending.focus = self.window.focus;
1254 currently_pending
1255 .keystrokes
1256 .push(key_down_event.keystroke.clone());
1257 for binding in bindings {
1258 currently_pending.bindings.push(binding);
1259 }
1260
1261 // for vim compatibility, we also should check "is input handler enabled"
1262 if !currently_pending.is_noop() {
1263 currently_pending.timer = Some(self.spawn(|mut cx| async move {
1264 cx.background_executor.timer(Duration::from_secs(1)).await;
1265 cx.update(move |cx| {
1266 cx.clear_pending_keystrokes();
1267 let Some(currently_pending) = cx.window.pending_input.take() else {
1268 return;
1269 };
1270 cx.replay_pending_input(currently_pending)
1271 })
1272 .log_err();
1273 }));
1274 } else {
1275 currently_pending.timer = None;
1276 }
1277 self.window.pending_input = Some(currently_pending);
1278
1279 self.propagate_event = false;
1280 return;
1281 } else if let Some(currently_pending) = self.window.pending_input.take() {
1282 if bindings
1283 .iter()
1284 .all(|binding| !currently_pending.used_by_binding(binding))
1285 {
1286 self.replay_pending_input(currently_pending)
1287 }
1288 }
1289
1290 if !bindings.is_empty() {
1291 self.clear_pending_keystrokes();
1292 }
1293
1294 self.propagate_event = true;
1295 for binding in bindings {
1296 self.dispatch_action_on_node(node_id, binding.action.boxed_clone());
1297 if !self.propagate_event {
1298 self.dispatch_keystroke_observers(event, Some(binding.action));
1299 return;
1300 }
1301 }
1302 }
1303
1304 // Capture phase
1305 for node_id in &dispatch_path {
1306 let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1307
1308 for key_listener in node.key_listeners.clone() {
1309 self.with_element_context(|cx| {
1310 key_listener(event, DispatchPhase::Capture, cx);
1311 });
1312 if !self.propagate_event {
1313 return;
1314 }
1315 }
1316 }
1317
1318 // Bubble phase
1319 for node_id in dispatch_path.iter().rev() {
1320 // Handle low level key events
1321 let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1322 for key_listener in node.key_listeners.clone() {
1323 self.with_element_context(|cx| {
1324 key_listener(event, DispatchPhase::Bubble, cx);
1325 });
1326 if !self.propagate_event {
1327 return;
1328 }
1329 }
1330 }
1331
1332 self.dispatch_keystroke_observers(event, None);
1333 }
1334
1335 /// Determine whether a potential multi-stroke key binding is in progress on this window.
1336 pub fn has_pending_keystrokes(&self) -> bool {
1337 self.window
1338 .rendered_frame
1339 .dispatch_tree
1340 .has_pending_keystrokes()
1341 }
1342
1343 fn replay_pending_input(&mut self, currently_pending: PendingInput) {
1344 let node_id = self
1345 .window
1346 .focus
1347 .and_then(|focus_id| {
1348 self.window
1349 .rendered_frame
1350 .dispatch_tree
1351 .focusable_node_id(focus_id)
1352 })
1353 .unwrap_or_else(|| self.window.rendered_frame.dispatch_tree.root_node_id());
1354
1355 if self.window.focus != currently_pending.focus {
1356 return;
1357 }
1358
1359 let input = currently_pending.input();
1360
1361 self.propagate_event = true;
1362 for binding in currently_pending.bindings {
1363 self.dispatch_action_on_node(node_id, binding.action.boxed_clone());
1364 if !self.propagate_event {
1365 return;
1366 }
1367 }
1368
1369 if !input.is_empty() {
1370 if let Some(mut input_handler) = self.window.platform_window.take_input_handler() {
1371 input_handler.flush_pending_input(&input, self);
1372 self.window.platform_window.set_input_handler(input_handler)
1373 }
1374 }
1375 }
1376
1377 fn dispatch_action_on_node(&mut self, node_id: DispatchNodeId, action: Box<dyn Action>) {
1378 let dispatch_path = self
1379 .window
1380 .rendered_frame
1381 .dispatch_tree
1382 .dispatch_path(node_id);
1383
1384 // Capture phase
1385 for node_id in &dispatch_path {
1386 let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1387 for DispatchActionListener {
1388 action_type,
1389 listener,
1390 } in node.action_listeners.clone()
1391 {
1392 let any_action = action.as_any();
1393 if action_type == any_action.type_id() {
1394 self.with_element_context(|cx| {
1395 listener(any_action, DispatchPhase::Capture, cx);
1396 });
1397
1398 if !self.propagate_event {
1399 return;
1400 }
1401 }
1402 }
1403 }
1404 // Bubble phase
1405 for node_id in dispatch_path.iter().rev() {
1406 let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1407 for DispatchActionListener {
1408 action_type,
1409 listener,
1410 } in node.action_listeners.clone()
1411 {
1412 let any_action = action.as_any();
1413 if action_type == any_action.type_id() {
1414 self.propagate_event = false; // Actions stop propagation by default during the bubble phase
1415
1416 self.with_element_context(|cx| {
1417 listener(any_action, DispatchPhase::Bubble, cx);
1418 });
1419
1420 if !self.propagate_event {
1421 return;
1422 }
1423 }
1424 }
1425 }
1426 }
1427
1428 /// Register the given handler to be invoked whenever the global of the given type
1429 /// is updated.
1430 pub fn observe_global<G: 'static>(
1431 &mut self,
1432 f: impl Fn(&mut WindowContext<'_>) + 'static,
1433 ) -> Subscription {
1434 let window_handle = self.window.handle;
1435 let (subscription, activate) = self.global_observers.insert(
1436 TypeId::of::<G>(),
1437 Box::new(move |cx| window_handle.update(cx, |_, cx| f(cx)).is_ok()),
1438 );
1439 self.app.defer(move |_| activate());
1440 subscription
1441 }
1442
1443 /// Focus the current window and bring it to the foreground at the platform level.
1444 pub fn activate_window(&self) {
1445 self.window.platform_window.activate();
1446 }
1447
1448 /// Minimize the current window at the platform level.
1449 pub fn minimize_window(&self) {
1450 self.window.platform_window.minimize();
1451 }
1452
1453 /// Toggle full screen status on the current window at the platform level.
1454 pub fn toggle_full_screen(&self) {
1455 self.window.platform_window.toggle_full_screen();
1456 }
1457
1458 /// Present a platform dialog.
1459 /// The provided message will be presented, along with buttons for each answer.
1460 /// When a button is clicked, the returned Receiver will receive the index of the clicked button.
1461 pub fn prompt(
1462 &self,
1463 level: PromptLevel,
1464 message: &str,
1465 answers: &[&str],
1466 ) -> oneshot::Receiver<usize> {
1467 self.window.platform_window.prompt(level, message, answers)
1468 }
1469
1470 /// Returns all available actions for the focused element.
1471 pub fn available_actions(&self) -> Vec<Box<dyn Action>> {
1472 let node_id = self
1473 .window
1474 .focus
1475 .and_then(|focus_id| {
1476 self.window
1477 .rendered_frame
1478 .dispatch_tree
1479 .focusable_node_id(focus_id)
1480 })
1481 .unwrap_or_else(|| self.window.rendered_frame.dispatch_tree.root_node_id());
1482
1483 self.window
1484 .rendered_frame
1485 .dispatch_tree
1486 .available_actions(node_id)
1487 }
1488
1489 /// Returns key bindings that invoke the given action on the currently focused element.
1490 pub fn bindings_for_action(&self, action: &dyn Action) -> Vec<KeyBinding> {
1491 self.window
1492 .rendered_frame
1493 .dispatch_tree
1494 .bindings_for_action(
1495 action,
1496 &self.window.rendered_frame.dispatch_tree.context_stack,
1497 )
1498 }
1499
1500 /// Returns any bindings that would invoke the given action on the given focus handle if it were focused.
1501 pub fn bindings_for_action_in(
1502 &self,
1503 action: &dyn Action,
1504 focus_handle: &FocusHandle,
1505 ) -> Vec<KeyBinding> {
1506 let dispatch_tree = &self.window.rendered_frame.dispatch_tree;
1507
1508 let Some(node_id) = dispatch_tree.focusable_node_id(focus_handle.id) else {
1509 return vec![];
1510 };
1511 let context_stack = dispatch_tree
1512 .dispatch_path(node_id)
1513 .into_iter()
1514 .filter_map(|node_id| dispatch_tree.node(node_id).context.clone())
1515 .collect();
1516 dispatch_tree.bindings_for_action(action, &context_stack)
1517 }
1518
1519 /// Returns a generic event listener that invokes the given listener with the view and context associated with the given view handle.
1520 pub fn listener_for<V: Render, E>(
1521 &self,
1522 view: &View<V>,
1523 f: impl Fn(&mut V, &E, &mut ViewContext<V>) + 'static,
1524 ) -> impl Fn(&E, &mut WindowContext) + 'static {
1525 let view = view.downgrade();
1526 move |e: &E, cx: &mut WindowContext| {
1527 view.update(cx, |view, cx| f(view, e, cx)).ok();
1528 }
1529 }
1530
1531 /// Returns a generic handler that invokes the given handler with the view and context associated with the given view handle.
1532 pub fn handler_for<V: Render>(
1533 &self,
1534 view: &View<V>,
1535 f: impl Fn(&mut V, &mut ViewContext<V>) + 'static,
1536 ) -> impl Fn(&mut WindowContext) {
1537 let view = view.downgrade();
1538 move |cx: &mut WindowContext| {
1539 view.update(cx, |view, cx| f(view, cx)).ok();
1540 }
1541 }
1542
1543 /// Register a callback that can interrupt the closing of the current window based the returned boolean.
1544 /// If the callback returns false, the window won't be closed.
1545 pub fn on_window_should_close(&mut self, f: impl Fn(&mut WindowContext) -> bool + 'static) {
1546 let mut this = self.to_async();
1547 self.window
1548 .platform_window
1549 .on_should_close(Box::new(move || {
1550 this.update(|cx| {
1551 // Ensure that the window is removed from the app if it's been closed
1552 // by always pre-empting the system close event.
1553 if f(cx) {
1554 cx.remove_window();
1555 }
1556 false
1557 })
1558 .unwrap_or(true)
1559 }))
1560 }
1561
1562 pub(crate) fn parent_view_id(&self) -> EntityId {
1563 *self
1564 .window
1565 .next_frame
1566 .view_stack
1567 .last()
1568 .expect("a view should always be on the stack while drawing")
1569 }
1570
1571 /// Register an action listener on the window for the next frame. The type of action
1572 /// is determined by the first parameter of the given listener. When the next frame is rendered
1573 /// the listener will be cleared.
1574 ///
1575 /// This is a fairly low-level method, so prefer using action handlers on elements unless you have
1576 /// a specific need to register a global listener.
1577 pub fn on_action(
1578 &mut self,
1579 action_type: TypeId,
1580 listener: impl Fn(&dyn Any, DispatchPhase, &mut WindowContext) + 'static,
1581 ) {
1582 self.window
1583 .next_frame
1584 .dispatch_tree
1585 .on_action(action_type, Rc::new(listener));
1586 }
1587}
1588
1589impl Context for WindowContext<'_> {
1590 type Result<T> = T;
1591
1592 fn new_model<T>(&mut self, build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T) -> Model<T>
1593 where
1594 T: 'static,
1595 {
1596 let slot = self.app.entities.reserve();
1597 let model = build_model(&mut ModelContext::new(&mut *self.app, slot.downgrade()));
1598 self.entities.insert(slot, model)
1599 }
1600
1601 fn update_model<T: 'static, R>(
1602 &mut self,
1603 model: &Model<T>,
1604 update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
1605 ) -> R {
1606 let mut entity = self.entities.lease(model);
1607 let result = update(
1608 &mut *entity,
1609 &mut ModelContext::new(&mut *self.app, model.downgrade()),
1610 );
1611 self.entities.end_lease(entity);
1612 result
1613 }
1614
1615 fn update_window<T, F>(&mut self, window: AnyWindowHandle, update: F) -> Result<T>
1616 where
1617 F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
1618 {
1619 if window == self.window.handle {
1620 let root_view = self.window.root_view.clone().unwrap();
1621 Ok(update(root_view, self))
1622 } else {
1623 window.update(self.app, update)
1624 }
1625 }
1626
1627 fn read_model<T, R>(
1628 &self,
1629 handle: &Model<T>,
1630 read: impl FnOnce(&T, &AppContext) -> R,
1631 ) -> Self::Result<R>
1632 where
1633 T: 'static,
1634 {
1635 let entity = self.entities.read(handle);
1636 read(entity, &*self.app)
1637 }
1638
1639 fn read_window<T, R>(
1640 &self,
1641 window: &WindowHandle<T>,
1642 read: impl FnOnce(View<T>, &AppContext) -> R,
1643 ) -> Result<R>
1644 where
1645 T: 'static,
1646 {
1647 if window.any_handle == self.window.handle {
1648 let root_view = self
1649 .window
1650 .root_view
1651 .clone()
1652 .unwrap()
1653 .downcast::<T>()
1654 .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
1655 Ok(read(root_view, self))
1656 } else {
1657 self.app.read_window(window, read)
1658 }
1659 }
1660}
1661
1662impl VisualContext for WindowContext<'_> {
1663 fn new_view<V>(
1664 &mut self,
1665 build_view_state: impl FnOnce(&mut ViewContext<'_, V>) -> V,
1666 ) -> Self::Result<View<V>>
1667 where
1668 V: 'static + Render,
1669 {
1670 let slot = self.app.entities.reserve();
1671 let view = View {
1672 model: slot.clone(),
1673 };
1674 let mut cx = ViewContext::new(&mut *self.app, &mut *self.window, &view);
1675 let entity = build_view_state(&mut cx);
1676 cx.entities.insert(slot, entity);
1677
1678 cx.new_view_observers
1679 .clone()
1680 .retain(&TypeId::of::<V>(), |observer| {
1681 let any_view = AnyView::from(view.clone());
1682 (observer)(any_view, self);
1683 true
1684 });
1685
1686 view
1687 }
1688
1689 /// Updates the given view. Prefer calling [`View::update`] instead, which calls this method.
1690 fn update_view<T: 'static, R>(
1691 &mut self,
1692 view: &View<T>,
1693 update: impl FnOnce(&mut T, &mut ViewContext<'_, T>) -> R,
1694 ) -> Self::Result<R> {
1695 let mut lease = self.app.entities.lease(&view.model);
1696 let mut cx = ViewContext::new(&mut *self.app, &mut *self.window, view);
1697 let result = update(&mut *lease, &mut cx);
1698 cx.app.entities.end_lease(lease);
1699 result
1700 }
1701
1702 fn replace_root_view<V>(
1703 &mut self,
1704 build_view: impl FnOnce(&mut ViewContext<'_, V>) -> V,
1705 ) -> Self::Result<View<V>>
1706 where
1707 V: 'static + Render,
1708 {
1709 let view = self.new_view(build_view);
1710 self.window.root_view = Some(view.clone().into());
1711 self.refresh();
1712 view
1713 }
1714
1715 fn focus_view<V: crate::FocusableView>(&mut self, view: &View<V>) -> Self::Result<()> {
1716 self.update_view(view, |view, cx| {
1717 view.focus_handle(cx).clone().focus(cx);
1718 })
1719 }
1720
1721 fn dismiss_view<V>(&mut self, view: &View<V>) -> Self::Result<()>
1722 where
1723 V: ManagedView,
1724 {
1725 self.update_view(view, |_, cx| cx.emit(DismissEvent))
1726 }
1727}
1728
1729impl<'a> std::ops::Deref for WindowContext<'a> {
1730 type Target = AppContext;
1731
1732 fn deref(&self) -> &Self::Target {
1733 self.app
1734 }
1735}
1736
1737impl<'a> std::ops::DerefMut for WindowContext<'a> {
1738 fn deref_mut(&mut self) -> &mut Self::Target {
1739 self.app
1740 }
1741}
1742
1743impl<'a> Borrow<AppContext> for WindowContext<'a> {
1744 fn borrow(&self) -> &AppContext {
1745 self.app
1746 }
1747}
1748
1749impl<'a> BorrowMut<AppContext> for WindowContext<'a> {
1750 fn borrow_mut(&mut self) -> &mut AppContext {
1751 self.app
1752 }
1753}
1754
1755/// This trait contains functionality that is shared across [`ViewContext`] and [`WindowContext`]
1756pub trait BorrowWindow: BorrowMut<Window> + BorrowMut<AppContext> {
1757 #[doc(hidden)]
1758 fn app_mut(&mut self) -> &mut AppContext {
1759 self.borrow_mut()
1760 }
1761
1762 #[doc(hidden)]
1763 fn app(&self) -> &AppContext {
1764 self.borrow()
1765 }
1766
1767 #[doc(hidden)]
1768 fn window(&self) -> &Window {
1769 self.borrow()
1770 }
1771
1772 #[doc(hidden)]
1773 fn window_mut(&mut self) -> &mut Window {
1774 self.borrow_mut()
1775 }
1776}
1777
1778impl Borrow<Window> for WindowContext<'_> {
1779 fn borrow(&self) -> &Window {
1780 self.window
1781 }
1782}
1783
1784impl BorrowMut<Window> for WindowContext<'_> {
1785 fn borrow_mut(&mut self) -> &mut Window {
1786 self.window
1787 }
1788}
1789
1790impl<T> BorrowWindow for T where T: BorrowMut<AppContext> + BorrowMut<Window> {}
1791
1792/// Provides access to application state that is specialized for a particular [`View`].
1793/// Allows you to interact with focus, emit events, etc.
1794/// ViewContext also derefs to [`WindowContext`], giving you access to all of its methods as well.
1795/// When you call [`View::update`], you're passed a `&mut V` and an `&mut ViewContext<V>`.
1796pub struct ViewContext<'a, V> {
1797 window_cx: WindowContext<'a>,
1798 view: &'a View<V>,
1799}
1800
1801impl<V> Borrow<AppContext> for ViewContext<'_, V> {
1802 fn borrow(&self) -> &AppContext {
1803 &*self.window_cx.app
1804 }
1805}
1806
1807impl<V> BorrowMut<AppContext> for ViewContext<'_, V> {
1808 fn borrow_mut(&mut self) -> &mut AppContext {
1809 &mut *self.window_cx.app
1810 }
1811}
1812
1813impl<V> Borrow<Window> for ViewContext<'_, V> {
1814 fn borrow(&self) -> &Window {
1815 &*self.window_cx.window
1816 }
1817}
1818
1819impl<V> BorrowMut<Window> for ViewContext<'_, V> {
1820 fn borrow_mut(&mut self) -> &mut Window {
1821 &mut *self.window_cx.window
1822 }
1823}
1824
1825impl<'a, V: 'static> ViewContext<'a, V> {
1826 pub(crate) fn new(app: &'a mut AppContext, window: &'a mut Window, view: &'a View<V>) -> Self {
1827 Self {
1828 window_cx: WindowContext::new(app, window),
1829 view,
1830 }
1831 }
1832
1833 /// Get the entity_id of this view.
1834 pub fn entity_id(&self) -> EntityId {
1835 self.view.entity_id()
1836 }
1837
1838 /// Get the view pointer underlying this context.
1839 pub fn view(&self) -> &View<V> {
1840 self.view
1841 }
1842
1843 /// Get the model underlying this view.
1844 pub fn model(&self) -> &Model<V> {
1845 &self.view.model
1846 }
1847
1848 /// Access the underlying window context.
1849 pub fn window_context(&mut self) -> &mut WindowContext<'a> {
1850 &mut self.window_cx
1851 }
1852
1853 /// Sets a given callback to be run on the next frame.
1854 pub fn on_next_frame(&mut self, f: impl FnOnce(&mut V, &mut ViewContext<V>) + 'static)
1855 where
1856 V: 'static,
1857 {
1858 let view = self.view().clone();
1859 self.window_cx.on_next_frame(move |cx| view.update(cx, f));
1860 }
1861
1862 /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
1863 /// that are currently on the stack to be returned to the app.
1864 pub fn defer(&mut self, f: impl FnOnce(&mut V, &mut ViewContext<V>) + 'static) {
1865 let view = self.view().downgrade();
1866 self.window_cx.defer(move |cx| {
1867 view.update(cx, f).ok();
1868 });
1869 }
1870
1871 /// Observe another model or view for changes to its state, as tracked by [`ModelContext::notify`].
1872 pub fn observe<V2, E>(
1873 &mut self,
1874 entity: &E,
1875 mut on_notify: impl FnMut(&mut V, E, &mut ViewContext<'_, V>) + 'static,
1876 ) -> Subscription
1877 where
1878 V2: 'static,
1879 V: 'static,
1880 E: Entity<V2>,
1881 {
1882 let view = self.view().downgrade();
1883 let entity_id = entity.entity_id();
1884 let entity = entity.downgrade();
1885 let window_handle = self.window.handle;
1886 let (subscription, activate) = self.app.observers.insert(
1887 entity_id,
1888 Box::new(move |cx| {
1889 window_handle
1890 .update(cx, |_, cx| {
1891 if let Some(handle) = E::upgrade_from(&entity) {
1892 view.update(cx, |this, cx| on_notify(this, handle, cx))
1893 .is_ok()
1894 } else {
1895 false
1896 }
1897 })
1898 .unwrap_or(false)
1899 }),
1900 );
1901 self.app.defer(move |_| activate());
1902 subscription
1903 }
1904
1905 /// Subscribe to events emitted by another model or view.
1906 /// The entity to which you're subscribing must implement the [`EventEmitter`] trait.
1907 /// The callback will be invoked with a reference to the current view, a handle to the emitting entity (either a [`View`] or [`Model`]), the event, and a view context for the current view.
1908 pub fn subscribe<V2, E, Evt>(
1909 &mut self,
1910 entity: &E,
1911 mut on_event: impl FnMut(&mut V, E, &Evt, &mut ViewContext<'_, V>) + 'static,
1912 ) -> Subscription
1913 where
1914 V2: EventEmitter<Evt>,
1915 E: Entity<V2>,
1916 Evt: 'static,
1917 {
1918 let view = self.view().downgrade();
1919 let entity_id = entity.entity_id();
1920 let handle = entity.downgrade();
1921 let window_handle = self.window.handle;
1922 let (subscription, activate) = self.app.event_listeners.insert(
1923 entity_id,
1924 (
1925 TypeId::of::<Evt>(),
1926 Box::new(move |event, cx| {
1927 window_handle
1928 .update(cx, |_, cx| {
1929 if let Some(handle) = E::upgrade_from(&handle) {
1930 let event = event.downcast_ref().expect("invalid event type");
1931 view.update(cx, |this, cx| on_event(this, handle, event, cx))
1932 .is_ok()
1933 } else {
1934 false
1935 }
1936 })
1937 .unwrap_or(false)
1938 }),
1939 ),
1940 );
1941 self.app.defer(move |_| activate());
1942 subscription
1943 }
1944
1945 /// Register a callback to be invoked when the view is released.
1946 ///
1947 /// The callback receives a handle to the view's window. This handle may be
1948 /// invalid, if the window was closed before the view was released.
1949 pub fn on_release(
1950 &mut self,
1951 on_release: impl FnOnce(&mut V, AnyWindowHandle, &mut AppContext) + 'static,
1952 ) -> Subscription {
1953 let window_handle = self.window.handle;
1954 let (subscription, activate) = self.app.release_listeners.insert(
1955 self.view.model.entity_id,
1956 Box::new(move |this, cx| {
1957 let this = this.downcast_mut().expect("invalid entity type");
1958 on_release(this, window_handle, cx)
1959 }),
1960 );
1961 activate();
1962 subscription
1963 }
1964
1965 /// Register a callback to be invoked when the given Model or View is released.
1966 pub fn observe_release<V2, E>(
1967 &mut self,
1968 entity: &E,
1969 mut on_release: impl FnMut(&mut V, &mut V2, &mut ViewContext<'_, V>) + 'static,
1970 ) -> Subscription
1971 where
1972 V: 'static,
1973 V2: 'static,
1974 E: Entity<V2>,
1975 {
1976 let view = self.view().downgrade();
1977 let entity_id = entity.entity_id();
1978 let window_handle = self.window.handle;
1979 let (subscription, activate) = self.app.release_listeners.insert(
1980 entity_id,
1981 Box::new(move |entity, cx| {
1982 let entity = entity.downcast_mut().expect("invalid entity type");
1983 let _ = window_handle.update(cx, |_, cx| {
1984 view.update(cx, |this, cx| on_release(this, entity, cx))
1985 });
1986 }),
1987 );
1988 activate();
1989 subscription
1990 }
1991
1992 /// Indicate that this view has changed, which will invoke any observers and also mark the window as dirty.
1993 /// If this view or any of its ancestors are *cached*, notifying it will cause it or its ancestors to be redrawn.
1994 pub fn notify(&mut self) {
1995 for view_id in self
1996 .window
1997 .rendered_frame
1998 .dispatch_tree
1999 .view_path(self.view.entity_id())
2000 .into_iter()
2001 .rev()
2002 {
2003 if !self.window.dirty_views.insert(view_id) {
2004 break;
2005 }
2006 }
2007
2008 if !self.window.drawing {
2009 self.window_cx.window.dirty = true;
2010 self.window_cx.app.push_effect(Effect::Notify {
2011 emitter: self.view.model.entity_id,
2012 });
2013 }
2014 }
2015
2016 /// Register a callback to be invoked when the window is resized.
2017 pub fn observe_window_bounds(
2018 &mut self,
2019 mut callback: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2020 ) -> Subscription {
2021 let view = self.view.downgrade();
2022 let (subscription, activate) = self.window.bounds_observers.insert(
2023 (),
2024 Box::new(move |cx| view.update(cx, |view, cx| callback(view, cx)).is_ok()),
2025 );
2026 activate();
2027 subscription
2028 }
2029
2030 /// Register a callback to be invoked when the window is activated or deactivated.
2031 pub fn observe_window_activation(
2032 &mut self,
2033 mut callback: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2034 ) -> Subscription {
2035 let view = self.view.downgrade();
2036 let (subscription, activate) = self.window.activation_observers.insert(
2037 (),
2038 Box::new(move |cx| view.update(cx, |view, cx| callback(view, cx)).is_ok()),
2039 );
2040 activate();
2041 subscription
2042 }
2043
2044 /// Register a listener to be called when the given focus handle receives focus.
2045 /// Returns a subscription and persists until the subscription is dropped.
2046 pub fn on_focus(
2047 &mut self,
2048 handle: &FocusHandle,
2049 mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2050 ) -> Subscription {
2051 let view = self.view.downgrade();
2052 let focus_id = handle.id;
2053 let (subscription, activate) = self.window.focus_listeners.insert(
2054 (),
2055 Box::new(move |event, cx| {
2056 view.update(cx, |view, cx| {
2057 if event.previous_focus_path.last() != Some(&focus_id)
2058 && event.current_focus_path.last() == Some(&focus_id)
2059 {
2060 listener(view, cx)
2061 }
2062 })
2063 .is_ok()
2064 }),
2065 );
2066 self.app.defer(move |_| activate());
2067 subscription
2068 }
2069
2070 /// Register a listener to be called when the given focus handle or one of its descendants receives focus.
2071 /// Returns a subscription and persists until the subscription is dropped.
2072 pub fn on_focus_in(
2073 &mut self,
2074 handle: &FocusHandle,
2075 mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2076 ) -> Subscription {
2077 let view = self.view.downgrade();
2078 let focus_id = handle.id;
2079 let (subscription, activate) = self.window.focus_listeners.insert(
2080 (),
2081 Box::new(move |event, cx| {
2082 view.update(cx, |view, cx| {
2083 if !event.previous_focus_path.contains(&focus_id)
2084 && event.current_focus_path.contains(&focus_id)
2085 {
2086 listener(view, cx)
2087 }
2088 })
2089 .is_ok()
2090 }),
2091 );
2092 self.app.defer(move |_| activate());
2093 subscription
2094 }
2095
2096 /// Register a listener to be called when the given focus handle loses focus.
2097 /// Returns a subscription and persists until the subscription is dropped.
2098 pub fn on_blur(
2099 &mut self,
2100 handle: &FocusHandle,
2101 mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2102 ) -> Subscription {
2103 let view = self.view.downgrade();
2104 let focus_id = handle.id;
2105 let (subscription, activate) = self.window.focus_listeners.insert(
2106 (),
2107 Box::new(move |event, cx| {
2108 view.update(cx, |view, cx| {
2109 if event.previous_focus_path.last() == Some(&focus_id)
2110 && event.current_focus_path.last() != Some(&focus_id)
2111 {
2112 listener(view, cx)
2113 }
2114 })
2115 .is_ok()
2116 }),
2117 );
2118 self.app.defer(move |_| activate());
2119 subscription
2120 }
2121
2122 /// Register a listener to be called when nothing in the window has focus.
2123 /// This typically happens when the node that was focused is removed from the tree,
2124 /// and this callback lets you chose a default place to restore the users focus.
2125 /// Returns a subscription and persists until the subscription is dropped.
2126 pub fn on_focus_lost(
2127 &mut self,
2128 mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2129 ) -> Subscription {
2130 let view = self.view.downgrade();
2131 let (subscription, activate) = self.window.focus_lost_listeners.insert(
2132 (),
2133 Box::new(move |cx| view.update(cx, |view, cx| listener(view, cx)).is_ok()),
2134 );
2135 activate();
2136 subscription
2137 }
2138
2139 /// Register a listener to be called when the given focus handle or one of its descendants loses focus.
2140 /// Returns a subscription and persists until the subscription is dropped.
2141 pub fn on_focus_out(
2142 &mut self,
2143 handle: &FocusHandle,
2144 mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2145 ) -> Subscription {
2146 let view = self.view.downgrade();
2147 let focus_id = handle.id;
2148 let (subscription, activate) = self.window.focus_listeners.insert(
2149 (),
2150 Box::new(move |event, cx| {
2151 view.update(cx, |view, cx| {
2152 if event.previous_focus_path.contains(&focus_id)
2153 && !event.current_focus_path.contains(&focus_id)
2154 {
2155 listener(view, cx)
2156 }
2157 })
2158 .is_ok()
2159 }),
2160 );
2161 self.app.defer(move |_| activate());
2162 subscription
2163 }
2164
2165 /// Schedule a future to be run asynchronously.
2166 /// The given callback is invoked with a [`WeakView<V>`] to avoid leaking the view for a long-running process.
2167 /// It's also given an [`AsyncWindowContext`], which can be used to access the state of the view across await points.
2168 /// The returned future will be polled on the main thread.
2169 pub fn spawn<Fut, R>(
2170 &mut self,
2171 f: impl FnOnce(WeakView<V>, AsyncWindowContext) -> Fut,
2172 ) -> Task<R>
2173 where
2174 R: 'static,
2175 Fut: Future<Output = R> + 'static,
2176 {
2177 let view = self.view().downgrade();
2178 self.window_cx.spawn(|cx| f(view, cx))
2179 }
2180
2181 /// Updates the global state of the given type.
2182 pub fn update_global<G, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R
2183 where
2184 G: 'static,
2185 {
2186 let mut global = self.app.lease_global::<G>();
2187 let result = f(&mut global, self);
2188 self.app.end_global_lease(global);
2189 result
2190 }
2191
2192 /// Register a callback to be invoked when the given global state changes.
2193 pub fn observe_global<G: 'static>(
2194 &mut self,
2195 mut f: impl FnMut(&mut V, &mut ViewContext<'_, V>) + 'static,
2196 ) -> Subscription {
2197 let window_handle = self.window.handle;
2198 let view = self.view().downgrade();
2199 let (subscription, activate) = self.global_observers.insert(
2200 TypeId::of::<G>(),
2201 Box::new(move |cx| {
2202 window_handle
2203 .update(cx, |_, cx| view.update(cx, |view, cx| f(view, cx)).is_ok())
2204 .unwrap_or(false)
2205 }),
2206 );
2207 self.app.defer(move |_| activate());
2208 subscription
2209 }
2210
2211 /// Register a callback to be invoked when the given Action type is dispatched to the window.
2212 pub fn on_action(
2213 &mut self,
2214 action_type: TypeId,
2215 listener: impl Fn(&mut V, &dyn Any, DispatchPhase, &mut ViewContext<V>) + 'static,
2216 ) {
2217 let handle = self.view().clone();
2218 self.window_cx
2219 .on_action(action_type, move |action, phase, cx| {
2220 handle.update(cx, |view, cx| {
2221 listener(view, action, phase, cx);
2222 })
2223 });
2224 }
2225
2226 /// Emit an event to be handled any other views that have subscribed via [ViewContext::subscribe].
2227 pub fn emit<Evt>(&mut self, event: Evt)
2228 where
2229 Evt: 'static,
2230 V: EventEmitter<Evt>,
2231 {
2232 let emitter = self.view.model.entity_id;
2233 self.app.push_effect(Effect::Emit {
2234 emitter,
2235 event_type: TypeId::of::<Evt>(),
2236 event: Box::new(event),
2237 });
2238 }
2239
2240 /// Move focus to the current view, assuming it implements [`FocusableView`].
2241 pub fn focus_self(&mut self)
2242 where
2243 V: FocusableView,
2244 {
2245 self.defer(|view, cx| view.focus_handle(cx).focus(cx))
2246 }
2247
2248 /// Convenience method for accessing view state in an event callback.
2249 ///
2250 /// Many GPUI callbacks take the form of `Fn(&E, &mut WindowContext)`,
2251 /// but it's often useful to be able to access view state in these
2252 /// callbacks. This method provides a convenient way to do so.
2253 pub fn listener<E>(
2254 &self,
2255 f: impl Fn(&mut V, &E, &mut ViewContext<V>) + 'static,
2256 ) -> impl Fn(&E, &mut WindowContext) + 'static {
2257 let view = self.view().downgrade();
2258 move |e: &E, cx: &mut WindowContext| {
2259 view.update(cx, |view, cx| f(view, e, cx)).ok();
2260 }
2261 }
2262}
2263
2264impl<V> Context for ViewContext<'_, V> {
2265 type Result<U> = U;
2266
2267 fn new_model<T: 'static>(
2268 &mut self,
2269 build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
2270 ) -> Model<T> {
2271 self.window_cx.new_model(build_model)
2272 }
2273
2274 fn update_model<T: 'static, R>(
2275 &mut self,
2276 model: &Model<T>,
2277 update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
2278 ) -> R {
2279 self.window_cx.update_model(model, update)
2280 }
2281
2282 fn update_window<T, F>(&mut self, window: AnyWindowHandle, update: F) -> Result<T>
2283 where
2284 F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
2285 {
2286 self.window_cx.update_window(window, update)
2287 }
2288
2289 fn read_model<T, R>(
2290 &self,
2291 handle: &Model<T>,
2292 read: impl FnOnce(&T, &AppContext) -> R,
2293 ) -> Self::Result<R>
2294 where
2295 T: 'static,
2296 {
2297 self.window_cx.read_model(handle, read)
2298 }
2299
2300 fn read_window<T, R>(
2301 &self,
2302 window: &WindowHandle<T>,
2303 read: impl FnOnce(View<T>, &AppContext) -> R,
2304 ) -> Result<R>
2305 where
2306 T: 'static,
2307 {
2308 self.window_cx.read_window(window, read)
2309 }
2310}
2311
2312impl<V: 'static> VisualContext for ViewContext<'_, V> {
2313 fn new_view<W: Render + 'static>(
2314 &mut self,
2315 build_view_state: impl FnOnce(&mut ViewContext<'_, W>) -> W,
2316 ) -> Self::Result<View<W>> {
2317 self.window_cx.new_view(build_view_state)
2318 }
2319
2320 fn update_view<V2: 'static, R>(
2321 &mut self,
2322 view: &View<V2>,
2323 update: impl FnOnce(&mut V2, &mut ViewContext<'_, V2>) -> R,
2324 ) -> Self::Result<R> {
2325 self.window_cx.update_view(view, update)
2326 }
2327
2328 fn replace_root_view<W>(
2329 &mut self,
2330 build_view: impl FnOnce(&mut ViewContext<'_, W>) -> W,
2331 ) -> Self::Result<View<W>>
2332 where
2333 W: 'static + Render,
2334 {
2335 self.window_cx.replace_root_view(build_view)
2336 }
2337
2338 fn focus_view<W: FocusableView>(&mut self, view: &View<W>) -> Self::Result<()> {
2339 self.window_cx.focus_view(view)
2340 }
2341
2342 fn dismiss_view<W: ManagedView>(&mut self, view: &View<W>) -> Self::Result<()> {
2343 self.window_cx.dismiss_view(view)
2344 }
2345}
2346
2347impl<'a, V> std::ops::Deref for ViewContext<'a, V> {
2348 type Target = WindowContext<'a>;
2349
2350 fn deref(&self) -> &Self::Target {
2351 &self.window_cx
2352 }
2353}
2354
2355impl<'a, V> std::ops::DerefMut for ViewContext<'a, V> {
2356 fn deref_mut(&mut self) -> &mut Self::Target {
2357 &mut self.window_cx
2358 }
2359}
2360
2361// #[derive(Clone, Copy, Eq, PartialEq, Hash)]
2362slotmap::new_key_type! {
2363 /// A unique identifier for a window.
2364 pub struct WindowId;
2365}
2366
2367impl WindowId {
2368 /// Converts this window ID to a `u64`.
2369 pub fn as_u64(&self) -> u64 {
2370 self.0.as_ffi()
2371 }
2372}
2373
2374/// A handle to a window with a specific root view type.
2375/// Note that this does not keep the window alive on its own.
2376#[derive(Deref, DerefMut)]
2377pub struct WindowHandle<V> {
2378 #[deref]
2379 #[deref_mut]
2380 pub(crate) any_handle: AnyWindowHandle,
2381 state_type: PhantomData<V>,
2382}
2383
2384impl<V: 'static + Render> WindowHandle<V> {
2385 /// Creates a new handle from a window ID.
2386 /// This does not check if the root type of the window is `V`.
2387 pub fn new(id: WindowId) -> Self {
2388 WindowHandle {
2389 any_handle: AnyWindowHandle {
2390 id,
2391 state_type: TypeId::of::<V>(),
2392 },
2393 state_type: PhantomData,
2394 }
2395 }
2396
2397 /// Get the root view out of this window.
2398 ///
2399 /// This will fail if the window is closed or if the root view's type does not match `V`.
2400 pub fn root<C>(&self, cx: &mut C) -> Result<View<V>>
2401 where
2402 C: Context,
2403 {
2404 Flatten::flatten(cx.update_window(self.any_handle, |root_view, _| {
2405 root_view
2406 .downcast::<V>()
2407 .map_err(|_| anyhow!("the type of the window's root view has changed"))
2408 }))
2409 }
2410
2411 /// Updates the root view of this window.
2412 ///
2413 /// This will fail if the window has been closed or if the root view's type does not match
2414 pub fn update<C, R>(
2415 &self,
2416 cx: &mut C,
2417 update: impl FnOnce(&mut V, &mut ViewContext<'_, V>) -> R,
2418 ) -> Result<R>
2419 where
2420 C: Context,
2421 {
2422 cx.update_window(self.any_handle, |root_view, cx| {
2423 let view = root_view
2424 .downcast::<V>()
2425 .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
2426 Ok(cx.update_view(&view, update))
2427 })?
2428 }
2429
2430 /// Read the root view out of this window.
2431 ///
2432 /// This will fail if the window is closed or if the root view's type does not match `V`.
2433 pub fn read<'a>(&self, cx: &'a AppContext) -> Result<&'a V> {
2434 let x = cx
2435 .windows
2436 .get(self.id)
2437 .and_then(|window| {
2438 window
2439 .as_ref()
2440 .and_then(|window| window.root_view.clone())
2441 .map(|root_view| root_view.downcast::<V>())
2442 })
2443 .ok_or_else(|| anyhow!("window not found"))?
2444 .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
2445
2446 Ok(x.read(cx))
2447 }
2448
2449 /// Read the root view out of this window, with a callback
2450 ///
2451 /// This will fail if the window is closed or if the root view's type does not match `V`.
2452 pub fn read_with<C, R>(&self, cx: &C, read_with: impl FnOnce(&V, &AppContext) -> R) -> Result<R>
2453 where
2454 C: Context,
2455 {
2456 cx.read_window(self, |root_view, cx| read_with(root_view.read(cx), cx))
2457 }
2458
2459 /// Read the root view pointer off of this window.
2460 ///
2461 /// This will fail if the window is closed or if the root view's type does not match `V`.
2462 pub fn root_view<C>(&self, cx: &C) -> Result<View<V>>
2463 where
2464 C: Context,
2465 {
2466 cx.read_window(self, |root_view, _cx| root_view.clone())
2467 }
2468
2469 /// Check if this window is 'active'.
2470 ///
2471 /// Will return `None` if the window is closed.
2472 pub fn is_active(&self, cx: &AppContext) -> Option<bool> {
2473 cx.windows
2474 .get(self.id)
2475 .and_then(|window| window.as_ref().map(|window| window.active))
2476 }
2477}
2478
2479impl<V> Copy for WindowHandle<V> {}
2480
2481impl<V> Clone for WindowHandle<V> {
2482 fn clone(&self) -> Self {
2483 *self
2484 }
2485}
2486
2487impl<V> PartialEq for WindowHandle<V> {
2488 fn eq(&self, other: &Self) -> bool {
2489 self.any_handle == other.any_handle
2490 }
2491}
2492
2493impl<V> Eq for WindowHandle<V> {}
2494
2495impl<V> Hash for WindowHandle<V> {
2496 fn hash<H: Hasher>(&self, state: &mut H) {
2497 self.any_handle.hash(state);
2498 }
2499}
2500
2501impl<V: 'static> From<WindowHandle<V>> for AnyWindowHandle {
2502 fn from(val: WindowHandle<V>) -> Self {
2503 val.any_handle
2504 }
2505}
2506
2507/// A handle to a window with any root view type, which can be downcast to a window with a specific root view type.
2508#[derive(Copy, Clone, PartialEq, Eq, Hash)]
2509pub struct AnyWindowHandle {
2510 pub(crate) id: WindowId,
2511 state_type: TypeId,
2512}
2513
2514impl AnyWindowHandle {
2515 /// Get the ID of this window.
2516 pub fn window_id(&self) -> WindowId {
2517 self.id
2518 }
2519
2520 /// Attempt to convert this handle to a window handle with a specific root view type.
2521 /// If the types do not match, this will return `None`.
2522 pub fn downcast<T: 'static>(&self) -> Option<WindowHandle<T>> {
2523 if TypeId::of::<T>() == self.state_type {
2524 Some(WindowHandle {
2525 any_handle: *self,
2526 state_type: PhantomData,
2527 })
2528 } else {
2529 None
2530 }
2531 }
2532
2533 /// Updates the state of the root view of this window.
2534 ///
2535 /// This will fail if the window has been closed.
2536 pub fn update<C, R>(
2537 self,
2538 cx: &mut C,
2539 update: impl FnOnce(AnyView, &mut WindowContext<'_>) -> R,
2540 ) -> Result<R>
2541 where
2542 C: Context,
2543 {
2544 cx.update_window(self, update)
2545 }
2546
2547 /// Read the state of the root view of this window.
2548 ///
2549 /// This will fail if the window has been closed.
2550 pub fn read<T, C, R>(self, cx: &C, read: impl FnOnce(View<T>, &AppContext) -> R) -> Result<R>
2551 where
2552 C: Context,
2553 T: 'static,
2554 {
2555 let view = self
2556 .downcast::<T>()
2557 .context("the type of the window's root view has changed")?;
2558
2559 cx.read_window(&view, read)
2560 }
2561}
2562
2563/// An identifier for an [`Element`](crate::Element).
2564///
2565/// Can be constructed with a string, a number, or both, as well
2566/// as other internal representations.
2567#[derive(Clone, Debug, Eq, PartialEq, Hash)]
2568pub enum ElementId {
2569 /// The ID of a View element
2570 View(EntityId),
2571 /// An integer ID.
2572 Integer(usize),
2573 /// A string based ID.
2574 Name(SharedString),
2575 /// An ID that's equated with a focus handle.
2576 FocusHandle(FocusId),
2577 /// A combination of a name and an integer.
2578 NamedInteger(SharedString, usize),
2579}
2580
2581impl Display for ElementId {
2582 fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
2583 match self {
2584 ElementId::View(entity_id) => write!(f, "view-{}", entity_id)?,
2585 ElementId::Integer(ix) => write!(f, "{}", ix)?,
2586 ElementId::Name(name) => write!(f, "{}", name)?,
2587 ElementId::FocusHandle(_) => write!(f, "FocusHandle")?,
2588 ElementId::NamedInteger(s, i) => write!(f, "{}-{}", s, i)?,
2589 }
2590
2591 Ok(())
2592 }
2593}
2594
2595impl ElementId {
2596 pub(crate) fn from_entity_id(entity_id: EntityId) -> Self {
2597 ElementId::View(entity_id)
2598 }
2599}
2600
2601impl TryInto<SharedString> for ElementId {
2602 type Error = anyhow::Error;
2603
2604 fn try_into(self) -> anyhow::Result<SharedString> {
2605 if let ElementId::Name(name) = self {
2606 Ok(name)
2607 } else {
2608 Err(anyhow!("element id is not string"))
2609 }
2610 }
2611}
2612
2613impl From<usize> for ElementId {
2614 fn from(id: usize) -> Self {
2615 ElementId::Integer(id)
2616 }
2617}
2618
2619impl From<i32> for ElementId {
2620 fn from(id: i32) -> Self {
2621 Self::Integer(id as usize)
2622 }
2623}
2624
2625impl From<SharedString> for ElementId {
2626 fn from(name: SharedString) -> Self {
2627 ElementId::Name(name)
2628 }
2629}
2630
2631impl From<&'static str> for ElementId {
2632 fn from(name: &'static str) -> Self {
2633 ElementId::Name(name.into())
2634 }
2635}
2636
2637impl<'a> From<&'a FocusHandle> for ElementId {
2638 fn from(handle: &'a FocusHandle) -> Self {
2639 ElementId::FocusHandle(handle.id)
2640 }
2641}
2642
2643impl From<(&'static str, EntityId)> for ElementId {
2644 fn from((name, id): (&'static str, EntityId)) -> Self {
2645 ElementId::NamedInteger(name.into(), id.as_u64() as usize)
2646 }
2647}
2648
2649impl From<(&'static str, usize)> for ElementId {
2650 fn from((name, id): (&'static str, usize)) -> Self {
2651 ElementId::NamedInteger(name.into(), id)
2652 }
2653}
2654
2655impl From<(&'static str, u64)> for ElementId {
2656 fn from((name, id): (&'static str, u64)) -> Self {
2657 ElementId::NamedInteger(name.into(), id as usize)
2658 }
2659}
2660
2661/// A rectangle to be rendered in the window at the given position and size.
2662/// Passed as an argument [`WindowContext::paint_quad`].
2663#[derive(Clone)]
2664pub struct PaintQuad {
2665 bounds: Bounds<Pixels>,
2666 corner_radii: Corners<Pixels>,
2667 background: Hsla,
2668 border_widths: Edges<Pixels>,
2669 border_color: Hsla,
2670}
2671
2672impl PaintQuad {
2673 /// Sets the corner radii of the quad.
2674 pub fn corner_radii(self, corner_radii: impl Into<Corners<Pixels>>) -> Self {
2675 PaintQuad {
2676 corner_radii: corner_radii.into(),
2677 ..self
2678 }
2679 }
2680
2681 /// Sets the border widths of the quad.
2682 pub fn border_widths(self, border_widths: impl Into<Edges<Pixels>>) -> Self {
2683 PaintQuad {
2684 border_widths: border_widths.into(),
2685 ..self
2686 }
2687 }
2688
2689 /// Sets the border color of the quad.
2690 pub fn border_color(self, border_color: impl Into<Hsla>) -> Self {
2691 PaintQuad {
2692 border_color: border_color.into(),
2693 ..self
2694 }
2695 }
2696
2697 /// Sets the background color of the quad.
2698 pub fn background(self, background: impl Into<Hsla>) -> Self {
2699 PaintQuad {
2700 background: background.into(),
2701 ..self
2702 }
2703 }
2704}
2705
2706/// Creates a quad with the given parameters.
2707pub fn quad(
2708 bounds: Bounds<Pixels>,
2709 corner_radii: impl Into<Corners<Pixels>>,
2710 background: impl Into<Hsla>,
2711 border_widths: impl Into<Edges<Pixels>>,
2712 border_color: impl Into<Hsla>,
2713) -> PaintQuad {
2714 PaintQuad {
2715 bounds,
2716 corner_radii: corner_radii.into(),
2717 background: background.into(),
2718 border_widths: border_widths.into(),
2719 border_color: border_color.into(),
2720 }
2721}
2722
2723/// Creates a filled quad with the given bounds and background color.
2724pub fn fill(bounds: impl Into<Bounds<Pixels>>, background: impl Into<Hsla>) -> PaintQuad {
2725 PaintQuad {
2726 bounds: bounds.into(),
2727 corner_radii: (0.).into(),
2728 background: background.into(),
2729 border_widths: (0.).into(),
2730 border_color: transparent_black(),
2731 }
2732}
2733
2734/// Creates a rectangle outline with the given bounds, border color, and a 1px border width
2735pub fn outline(bounds: impl Into<Bounds<Pixels>>, border_color: impl Into<Hsla>) -> PaintQuad {
2736 PaintQuad {
2737 bounds: bounds.into(),
2738 corner_radii: (0.).into(),
2739 background: transparent_black(),
2740 border_widths: (1.).into(),
2741 border_color: border_color.into(),
2742 }
2743}