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 level: &StackingOrder,
881 ) -> bool {
882 for (opaque_level, _, bounds) in self.window.rendered_frame.depth_map.iter() {
883 if level >= opaque_level {
884 break;
885 }
886
887 if opaque_level
888 .first()
889 .map(|c| c.z_index == ACTIVE_DRAG_Z_INDEX)
890 .unwrap_or(false)
891 {
892 continue;
893 }
894
895 if bounds.contains(point) {
896 return false;
897 }
898 }
899 true
900 }
901
902 /// Called during painting to get the current stacking order.
903 pub fn stacking_order(&self) -> &StackingOrder {
904 &self.window.next_frame.z_index_stack
905 }
906
907 /// Draw pixels to the display for this window based on the contents of its scene.
908 pub(crate) fn draw(&mut self) {
909 self.window.dirty = false;
910 self.window.drawing = true;
911
912 #[cfg(any(test, feature = "test-support"))]
913 {
914 self.window.focus_invalidated = false;
915 }
916
917 if let Some(requested_handler) = self.window.rendered_frame.requested_input_handler.as_mut()
918 {
919 let input_handler = self.window.platform_window.take_input_handler();
920 requested_handler.handler = input_handler;
921 }
922
923 let root_view = self.window.root_view.take().unwrap();
924 self.with_element_context(|cx| {
925 cx.with_z_index(0, |cx| {
926 cx.with_key_dispatch(Some(KeyContext::default()), None, |_, cx| {
927 // We need to use cx.cx here so we can utilize borrow splitting
928 for (action_type, action_listeners) in &cx.cx.app.global_action_listeners {
929 for action_listener in action_listeners.iter().cloned() {
930 cx.cx.window.next_frame.dispatch_tree.on_action(
931 *action_type,
932 Rc::new(
933 move |action: &dyn Any, phase, cx: &mut WindowContext<'_>| {
934 action_listener(action, phase, cx)
935 },
936 ),
937 )
938 }
939 }
940
941 let available_space = cx.window.viewport_size.map(Into::into);
942 root_view.draw(Point::default(), available_space, cx);
943 })
944 })
945 });
946
947 if let Some(active_drag) = self.app.active_drag.take() {
948 self.with_element_context(|cx| {
949 cx.with_z_index(ACTIVE_DRAG_Z_INDEX, |cx| {
950 let offset = cx.mouse_position() - active_drag.cursor_offset;
951 let available_space =
952 size(AvailableSpace::MinContent, AvailableSpace::MinContent);
953 active_drag.view.draw(offset, available_space, cx);
954 })
955 });
956 self.active_drag = Some(active_drag);
957 } else if let Some(tooltip_request) = self.window.next_frame.tooltip_request.take() {
958 self.with_element_context(|cx| {
959 cx.with_z_index(1, |cx| {
960 let available_space =
961 size(AvailableSpace::MinContent, AvailableSpace::MinContent);
962 tooltip_request.tooltip.view.draw(
963 tooltip_request.tooltip.cursor_offset,
964 available_space,
965 cx,
966 );
967 })
968 });
969 self.window.next_frame.tooltip_request = Some(tooltip_request);
970 }
971 self.window.dirty_views.clear();
972
973 self.window
974 .next_frame
975 .dispatch_tree
976 .preserve_pending_keystrokes(
977 &mut self.window.rendered_frame.dispatch_tree,
978 self.window.focus,
979 );
980 self.window.next_frame.focus = self.window.focus;
981 self.window.next_frame.window_active = self.window.active;
982 self.window.root_view = Some(root_view);
983
984 // Set the cursor only if we're the active window.
985 let cursor_style = self
986 .window
987 .next_frame
988 .requested_cursor_style
989 .take()
990 .unwrap_or(CursorStyle::Arrow);
991 if self.is_window_active() {
992 self.platform.set_cursor_style(cursor_style);
993 }
994
995 // Register requested input handler with the platform window.
996 if let Some(requested_input) = self.window.next_frame.requested_input_handler.as_mut() {
997 if let Some(handler) = requested_input.handler.take() {
998 self.window.platform_window.set_input_handler(handler);
999 }
1000 }
1001
1002 self.window.layout_engine.as_mut().unwrap().clear();
1003 self.text_system()
1004 .finish_frame(&self.window.next_frame.reused_views);
1005 self.window
1006 .next_frame
1007 .finish(&mut self.window.rendered_frame);
1008 ELEMENT_ARENA.with_borrow_mut(|element_arena| element_arena.clear());
1009
1010 let previous_focus_path = self.window.rendered_frame.focus_path();
1011 let previous_window_active = self.window.rendered_frame.window_active;
1012 mem::swap(&mut self.window.rendered_frame, &mut self.window.next_frame);
1013 self.window.next_frame.clear();
1014 let current_focus_path = self.window.rendered_frame.focus_path();
1015 let current_window_active = self.window.rendered_frame.window_active;
1016
1017 if previous_focus_path != current_focus_path
1018 || previous_window_active != current_window_active
1019 {
1020 if !previous_focus_path.is_empty() && current_focus_path.is_empty() {
1021 self.window
1022 .focus_lost_listeners
1023 .clone()
1024 .retain(&(), |listener| listener(self));
1025 }
1026
1027 let event = FocusEvent {
1028 previous_focus_path: if previous_window_active {
1029 previous_focus_path
1030 } else {
1031 Default::default()
1032 },
1033 current_focus_path: if current_window_active {
1034 current_focus_path
1035 } else {
1036 Default::default()
1037 },
1038 };
1039 self.window
1040 .focus_listeners
1041 .clone()
1042 .retain(&(), |listener| listener(&event, self));
1043 }
1044
1045 self.window
1046 .platform_window
1047 .draw(&self.window.rendered_frame.scene);
1048 self.window.refreshing = false;
1049 self.window.drawing = false;
1050 }
1051
1052 /// Dispatch a mouse or keyboard event on the window.
1053 pub fn dispatch_event(&mut self, event: PlatformInput) -> bool {
1054 // Handlers may set this to false by calling `stop_propagation`.
1055 self.app.propagate_event = true;
1056 // Handlers may set this to true by calling `prevent_default`.
1057 self.window.default_prevented = false;
1058
1059 let event = match event {
1060 // Track the mouse position with our own state, since accessing the platform
1061 // API for the mouse position can only occur on the main thread.
1062 PlatformInput::MouseMove(mouse_move) => {
1063 self.window.mouse_position = mouse_move.position;
1064 self.window.modifiers = mouse_move.modifiers;
1065 PlatformInput::MouseMove(mouse_move)
1066 }
1067 PlatformInput::MouseDown(mouse_down) => {
1068 self.window.mouse_position = mouse_down.position;
1069 self.window.modifiers = mouse_down.modifiers;
1070 PlatformInput::MouseDown(mouse_down)
1071 }
1072 PlatformInput::MouseUp(mouse_up) => {
1073 self.window.mouse_position = mouse_up.position;
1074 self.window.modifiers = mouse_up.modifiers;
1075 PlatformInput::MouseUp(mouse_up)
1076 }
1077 PlatformInput::MouseExited(mouse_exited) => {
1078 self.window.modifiers = mouse_exited.modifiers;
1079 PlatformInput::MouseExited(mouse_exited)
1080 }
1081 PlatformInput::ModifiersChanged(modifiers_changed) => {
1082 self.window.modifiers = modifiers_changed.modifiers;
1083 PlatformInput::ModifiersChanged(modifiers_changed)
1084 }
1085 PlatformInput::ScrollWheel(scroll_wheel) => {
1086 self.window.mouse_position = scroll_wheel.position;
1087 self.window.modifiers = scroll_wheel.modifiers;
1088 PlatformInput::ScrollWheel(scroll_wheel)
1089 }
1090 // Translate dragging and dropping of external files from the operating system
1091 // to internal drag and drop events.
1092 PlatformInput::FileDrop(file_drop) => match file_drop {
1093 FileDropEvent::Entered { position, paths } => {
1094 self.window.mouse_position = position;
1095 if self.active_drag.is_none() {
1096 self.active_drag = Some(AnyDrag {
1097 value: Box::new(paths.clone()),
1098 view: self.new_view(|_| paths).into(),
1099 cursor_offset: position,
1100 });
1101 }
1102 PlatformInput::MouseMove(MouseMoveEvent {
1103 position,
1104 pressed_button: Some(MouseButton::Left),
1105 modifiers: Modifiers::default(),
1106 })
1107 }
1108 FileDropEvent::Pending { position } => {
1109 self.window.mouse_position = position;
1110 PlatformInput::MouseMove(MouseMoveEvent {
1111 position,
1112 pressed_button: Some(MouseButton::Left),
1113 modifiers: Modifiers::default(),
1114 })
1115 }
1116 FileDropEvent::Submit { position } => {
1117 self.activate(true);
1118 self.window.mouse_position = position;
1119 PlatformInput::MouseUp(MouseUpEvent {
1120 button: MouseButton::Left,
1121 position,
1122 modifiers: Modifiers::default(),
1123 click_count: 1,
1124 })
1125 }
1126 FileDropEvent::Exited => PlatformInput::MouseUp(MouseUpEvent {
1127 button: MouseButton::Left,
1128 position: Point::default(),
1129 modifiers: Modifiers::default(),
1130 click_count: 1,
1131 }),
1132 },
1133 PlatformInput::KeyDown(_) | PlatformInput::KeyUp(_) => event,
1134 };
1135
1136 if let Some(any_mouse_event) = event.mouse_event() {
1137 self.dispatch_mouse_event(any_mouse_event);
1138 } else if let Some(any_key_event) = event.keyboard_event() {
1139 self.dispatch_key_event(any_key_event);
1140 }
1141
1142 !self.app.propagate_event
1143 }
1144
1145 fn dispatch_mouse_event(&mut self, event: &dyn Any) {
1146 if let Some(mut handlers) = self
1147 .window
1148 .rendered_frame
1149 .mouse_listeners
1150 .remove(&event.type_id())
1151 {
1152 // Because handlers may add other handlers, we sort every time.
1153 handlers.sort_by(|(a, _, _), (b, _, _)| a.cmp(b));
1154
1155 // Capture phase, events bubble from back to front. Handlers for this phase are used for
1156 // special purposes, such as detecting events outside of a given Bounds.
1157 for (_, _, handler) in &mut handlers {
1158 self.with_element_context(|cx| {
1159 handler(event, DispatchPhase::Capture, cx);
1160 });
1161 if !self.app.propagate_event {
1162 break;
1163 }
1164 }
1165
1166 // Bubble phase, where most normal handlers do their work.
1167 if self.app.propagate_event {
1168 for (_, _, handler) in handlers.iter_mut().rev() {
1169 self.with_element_context(|cx| {
1170 handler(event, DispatchPhase::Bubble, cx);
1171 });
1172 if !self.app.propagate_event {
1173 break;
1174 }
1175 }
1176 }
1177
1178 self.window
1179 .rendered_frame
1180 .mouse_listeners
1181 .insert(event.type_id(), handlers);
1182 }
1183
1184 if self.app.propagate_event && self.has_active_drag() {
1185 if event.is::<MouseMoveEvent>() {
1186 // If this was a mouse move event, redraw the window so that the
1187 // active drag can follow the mouse cursor.
1188 self.refresh();
1189 } else if event.is::<MouseUpEvent>() {
1190 // If this was a mouse up event, cancel the active drag and redraw
1191 // the window.
1192 self.active_drag = None;
1193 self.refresh();
1194 }
1195 }
1196 }
1197
1198 fn dispatch_key_event(&mut self, event: &dyn Any) {
1199 let node_id = self
1200 .window
1201 .focus
1202 .and_then(|focus_id| {
1203 self.window
1204 .rendered_frame
1205 .dispatch_tree
1206 .focusable_node_id(focus_id)
1207 })
1208 .unwrap_or_else(|| self.window.rendered_frame.dispatch_tree.root_node_id());
1209
1210 let dispatch_path = self
1211 .window
1212 .rendered_frame
1213 .dispatch_tree
1214 .dispatch_path(node_id);
1215
1216 if let Some(key_down_event) = event.downcast_ref::<KeyDownEvent>() {
1217 let KeymatchResult { bindings, pending } = self
1218 .window
1219 .rendered_frame
1220 .dispatch_tree
1221 .dispatch_key(&key_down_event.keystroke, &dispatch_path);
1222
1223 if pending {
1224 let mut currently_pending = self.window.pending_input.take().unwrap_or_default();
1225 if currently_pending.focus.is_some() && currently_pending.focus != self.window.focus
1226 {
1227 currently_pending = PendingInput::default();
1228 }
1229 currently_pending.focus = self.window.focus;
1230 currently_pending
1231 .keystrokes
1232 .push(key_down_event.keystroke.clone());
1233 for binding in bindings {
1234 currently_pending.bindings.push(binding);
1235 }
1236
1237 // for vim compatibility, we also should check "is input handler enabled"
1238 if !currently_pending.is_noop() {
1239 currently_pending.timer = Some(self.spawn(|mut cx| async move {
1240 cx.background_executor.timer(Duration::from_secs(1)).await;
1241 cx.update(move |cx| {
1242 cx.clear_pending_keystrokes();
1243 let Some(currently_pending) = cx.window.pending_input.take() else {
1244 return;
1245 };
1246 cx.replay_pending_input(currently_pending)
1247 })
1248 .log_err();
1249 }));
1250 } else {
1251 currently_pending.timer = None;
1252 }
1253 self.window.pending_input = Some(currently_pending);
1254
1255 self.propagate_event = false;
1256 return;
1257 } else if let Some(currently_pending) = self.window.pending_input.take() {
1258 if bindings
1259 .iter()
1260 .all(|binding| !currently_pending.used_by_binding(&binding))
1261 {
1262 self.replay_pending_input(currently_pending)
1263 }
1264 }
1265
1266 if !bindings.is_empty() {
1267 self.clear_pending_keystrokes();
1268 }
1269
1270 self.propagate_event = true;
1271 for binding in bindings {
1272 self.dispatch_action_on_node(node_id, binding.action.boxed_clone());
1273 if !self.propagate_event {
1274 self.dispatch_keystroke_observers(event, Some(binding.action));
1275 return;
1276 }
1277 }
1278 }
1279
1280 // Capture phase
1281 for node_id in &dispatch_path {
1282 let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1283
1284 for key_listener in node.key_listeners.clone() {
1285 self.with_element_context(|cx| {
1286 key_listener(event, DispatchPhase::Capture, cx);
1287 });
1288 if !self.propagate_event {
1289 return;
1290 }
1291 }
1292 }
1293
1294 // Bubble phase
1295 for node_id in dispatch_path.iter().rev() {
1296 // Handle low level key events
1297 let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1298 for key_listener in node.key_listeners.clone() {
1299 self.with_element_context(|cx| {
1300 key_listener(event, DispatchPhase::Bubble, cx);
1301 });
1302 if !self.propagate_event {
1303 return;
1304 }
1305 }
1306 }
1307
1308 self.dispatch_keystroke_observers(event, None);
1309 }
1310
1311 /// Determine whether a potential multi-stroke key binding is in progress on this window.
1312 pub fn has_pending_keystrokes(&self) -> bool {
1313 self.window
1314 .rendered_frame
1315 .dispatch_tree
1316 .has_pending_keystrokes()
1317 }
1318
1319 fn replay_pending_input(&mut self, currently_pending: PendingInput) {
1320 let node_id = self
1321 .window
1322 .focus
1323 .and_then(|focus_id| {
1324 self.window
1325 .rendered_frame
1326 .dispatch_tree
1327 .focusable_node_id(focus_id)
1328 })
1329 .unwrap_or_else(|| self.window.rendered_frame.dispatch_tree.root_node_id());
1330
1331 if self.window.focus != currently_pending.focus {
1332 return;
1333 }
1334
1335 let input = currently_pending.input();
1336
1337 self.propagate_event = true;
1338 for binding in currently_pending.bindings {
1339 self.dispatch_action_on_node(node_id, binding.action.boxed_clone());
1340 if !self.propagate_event {
1341 return;
1342 }
1343 }
1344
1345 if !input.is_empty() {
1346 if let Some(mut input_handler) = self.window.platform_window.take_input_handler() {
1347 input_handler.flush_pending_input(&input, self);
1348 self.window.platform_window.set_input_handler(input_handler)
1349 }
1350 }
1351 }
1352
1353 fn dispatch_action_on_node(&mut self, node_id: DispatchNodeId, action: Box<dyn Action>) {
1354 let dispatch_path = self
1355 .window
1356 .rendered_frame
1357 .dispatch_tree
1358 .dispatch_path(node_id);
1359
1360 // Capture phase
1361 for node_id in &dispatch_path {
1362 let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1363 for DispatchActionListener {
1364 action_type,
1365 listener,
1366 } in node.action_listeners.clone()
1367 {
1368 let any_action = action.as_any();
1369 if action_type == any_action.type_id() {
1370 self.with_element_context(|cx| {
1371 listener(any_action, DispatchPhase::Capture, cx);
1372 });
1373
1374 if !self.propagate_event {
1375 return;
1376 }
1377 }
1378 }
1379 }
1380 // Bubble phase
1381 for node_id in dispatch_path.iter().rev() {
1382 let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1383 for DispatchActionListener {
1384 action_type,
1385 listener,
1386 } in node.action_listeners.clone()
1387 {
1388 let any_action = action.as_any();
1389 if action_type == any_action.type_id() {
1390 self.propagate_event = false; // Actions stop propagation by default during the bubble phase
1391
1392 self.with_element_context(|cx| {
1393 listener(any_action, DispatchPhase::Bubble, cx);
1394 });
1395
1396 if !self.propagate_event {
1397 return;
1398 }
1399 }
1400 }
1401 }
1402 }
1403
1404 /// Register the given handler to be invoked whenever the global of the given type
1405 /// is updated.
1406 pub fn observe_global<G: 'static>(
1407 &mut self,
1408 f: impl Fn(&mut WindowContext<'_>) + 'static,
1409 ) -> Subscription {
1410 let window_handle = self.window.handle;
1411 let (subscription, activate) = self.global_observers.insert(
1412 TypeId::of::<G>(),
1413 Box::new(move |cx| window_handle.update(cx, |_, cx| f(cx)).is_ok()),
1414 );
1415 self.app.defer(move |_| activate());
1416 subscription
1417 }
1418
1419 /// Focus the current window and bring it to the foreground at the platform level.
1420 pub fn activate_window(&self) {
1421 self.window.platform_window.activate();
1422 }
1423
1424 /// Minimize the current window at the platform level.
1425 pub fn minimize_window(&self) {
1426 self.window.platform_window.minimize();
1427 }
1428
1429 /// Toggle full screen status on the current window at the platform level.
1430 pub fn toggle_full_screen(&self) {
1431 self.window.platform_window.toggle_full_screen();
1432 }
1433
1434 /// Present a platform dialog.
1435 /// The provided message will be presented, along with buttons for each answer.
1436 /// When a button is clicked, the returned Receiver will receive the index of the clicked button.
1437 pub fn prompt(
1438 &self,
1439 level: PromptLevel,
1440 message: &str,
1441 answers: &[&str],
1442 ) -> oneshot::Receiver<usize> {
1443 self.window.platform_window.prompt(level, message, answers)
1444 }
1445
1446 /// Returns all available actions for the focused element.
1447 pub fn available_actions(&self) -> Vec<Box<dyn Action>> {
1448 let node_id = self
1449 .window
1450 .focus
1451 .and_then(|focus_id| {
1452 self.window
1453 .rendered_frame
1454 .dispatch_tree
1455 .focusable_node_id(focus_id)
1456 })
1457 .unwrap_or_else(|| self.window.rendered_frame.dispatch_tree.root_node_id());
1458
1459 self.window
1460 .rendered_frame
1461 .dispatch_tree
1462 .available_actions(node_id)
1463 }
1464
1465 /// Returns key bindings that invoke the given action on the currently focused element.
1466 pub fn bindings_for_action(&self, action: &dyn Action) -> Vec<KeyBinding> {
1467 self.window
1468 .rendered_frame
1469 .dispatch_tree
1470 .bindings_for_action(
1471 action,
1472 &self.window.rendered_frame.dispatch_tree.context_stack,
1473 )
1474 }
1475
1476 /// Returns any bindings that would invoke the given action on the given focus handle if it were focused.
1477 pub fn bindings_for_action_in(
1478 &self,
1479 action: &dyn Action,
1480 focus_handle: &FocusHandle,
1481 ) -> Vec<KeyBinding> {
1482 let dispatch_tree = &self.window.rendered_frame.dispatch_tree;
1483
1484 let Some(node_id) = dispatch_tree.focusable_node_id(focus_handle.id) else {
1485 return vec![];
1486 };
1487 let context_stack = dispatch_tree
1488 .dispatch_path(node_id)
1489 .into_iter()
1490 .filter_map(|node_id| dispatch_tree.node(node_id).context.clone())
1491 .collect();
1492 dispatch_tree.bindings_for_action(action, &context_stack)
1493 }
1494
1495 /// Returns a generic event listener that invokes the given listener with the view and context associated with the given view handle.
1496 pub fn listener_for<V: Render, E>(
1497 &self,
1498 view: &View<V>,
1499 f: impl Fn(&mut V, &E, &mut ViewContext<V>) + 'static,
1500 ) -> impl Fn(&E, &mut WindowContext) + 'static {
1501 let view = view.downgrade();
1502 move |e: &E, cx: &mut WindowContext| {
1503 view.update(cx, |view, cx| f(view, e, cx)).ok();
1504 }
1505 }
1506
1507 /// Returns a generic handler that invokes the given handler with the view and context associated with the given view handle.
1508 pub fn handler_for<V: Render>(
1509 &self,
1510 view: &View<V>,
1511 f: impl Fn(&mut V, &mut ViewContext<V>) + 'static,
1512 ) -> impl Fn(&mut WindowContext) {
1513 let view = view.downgrade();
1514 move |cx: &mut WindowContext| {
1515 view.update(cx, |view, cx| f(view, cx)).ok();
1516 }
1517 }
1518
1519 /// Register a callback that can interrupt the closing of the current window based the returned boolean.
1520 /// If the callback returns false, the window won't be closed.
1521 pub fn on_window_should_close(&mut self, f: impl Fn(&mut WindowContext) -> bool + 'static) {
1522 let mut this = self.to_async();
1523 self.window
1524 .platform_window
1525 .on_should_close(Box::new(move || {
1526 this.update(|cx| {
1527 // Ensure that the window is removed from the app if it's been closed
1528 // by always pre-empting the system close event.
1529 if f(cx) {
1530 cx.remove_window();
1531 }
1532 false
1533 })
1534 .unwrap_or(true)
1535 }))
1536 }
1537
1538 pub(crate) fn parent_view_id(&self) -> EntityId {
1539 *self
1540 .window
1541 .next_frame
1542 .view_stack
1543 .last()
1544 .expect("a view should always be on the stack while drawing")
1545 }
1546
1547 /// Register an action listener on the window for the next frame. The type of action
1548 /// is determined by the first parameter of the given listener. When the next frame is rendered
1549 /// the listener will be cleared.
1550 ///
1551 /// This is a fairly low-level method, so prefer using action handlers on elements unless you have
1552 /// a specific need to register a global listener.
1553 pub fn on_action(
1554 &mut self,
1555 action_type: TypeId,
1556 listener: impl Fn(&dyn Any, DispatchPhase, &mut WindowContext) + 'static,
1557 ) {
1558 self.window
1559 .next_frame
1560 .dispatch_tree
1561 .on_action(action_type, Rc::new(listener));
1562 }
1563}
1564
1565impl Context for WindowContext<'_> {
1566 type Result<T> = T;
1567
1568 fn new_model<T>(&mut self, build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T) -> Model<T>
1569 where
1570 T: 'static,
1571 {
1572 let slot = self.app.entities.reserve();
1573 let model = build_model(&mut ModelContext::new(&mut *self.app, slot.downgrade()));
1574 self.entities.insert(slot, model)
1575 }
1576
1577 fn update_model<T: 'static, R>(
1578 &mut self,
1579 model: &Model<T>,
1580 update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
1581 ) -> R {
1582 let mut entity = self.entities.lease(model);
1583 let result = update(
1584 &mut *entity,
1585 &mut ModelContext::new(&mut *self.app, model.downgrade()),
1586 );
1587 self.entities.end_lease(entity);
1588 result
1589 }
1590
1591 fn update_window<T, F>(&mut self, window: AnyWindowHandle, update: F) -> Result<T>
1592 where
1593 F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
1594 {
1595 if window == self.window.handle {
1596 let root_view = self.window.root_view.clone().unwrap();
1597 Ok(update(root_view, self))
1598 } else {
1599 window.update(self.app, update)
1600 }
1601 }
1602
1603 fn read_model<T, R>(
1604 &self,
1605 handle: &Model<T>,
1606 read: impl FnOnce(&T, &AppContext) -> R,
1607 ) -> Self::Result<R>
1608 where
1609 T: 'static,
1610 {
1611 let entity = self.entities.read(handle);
1612 read(entity, &*self.app)
1613 }
1614
1615 fn read_window<T, R>(
1616 &self,
1617 window: &WindowHandle<T>,
1618 read: impl FnOnce(View<T>, &AppContext) -> R,
1619 ) -> Result<R>
1620 where
1621 T: 'static,
1622 {
1623 if window.any_handle == self.window.handle {
1624 let root_view = self
1625 .window
1626 .root_view
1627 .clone()
1628 .unwrap()
1629 .downcast::<T>()
1630 .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
1631 Ok(read(root_view, self))
1632 } else {
1633 self.app.read_window(window, read)
1634 }
1635 }
1636}
1637
1638impl VisualContext for WindowContext<'_> {
1639 fn new_view<V>(
1640 &mut self,
1641 build_view_state: impl FnOnce(&mut ViewContext<'_, V>) -> V,
1642 ) -> Self::Result<View<V>>
1643 where
1644 V: 'static + Render,
1645 {
1646 let slot = self.app.entities.reserve();
1647 let view = View {
1648 model: slot.clone(),
1649 };
1650 let mut cx = ViewContext::new(&mut *self.app, &mut *self.window, &view);
1651 let entity = build_view_state(&mut cx);
1652 cx.entities.insert(slot, entity);
1653
1654 cx.new_view_observers
1655 .clone()
1656 .retain(&TypeId::of::<V>(), |observer| {
1657 let any_view = AnyView::from(view.clone());
1658 (observer)(any_view, self);
1659 true
1660 });
1661
1662 view
1663 }
1664
1665 /// Updates the given view. Prefer calling [`View::update`] instead, which calls this method.
1666 fn update_view<T: 'static, R>(
1667 &mut self,
1668 view: &View<T>,
1669 update: impl FnOnce(&mut T, &mut ViewContext<'_, T>) -> R,
1670 ) -> Self::Result<R> {
1671 let mut lease = self.app.entities.lease(&view.model);
1672 let mut cx = ViewContext::new(&mut *self.app, &mut *self.window, view);
1673 let result = update(&mut *lease, &mut cx);
1674 cx.app.entities.end_lease(lease);
1675 result
1676 }
1677
1678 fn replace_root_view<V>(
1679 &mut self,
1680 build_view: impl FnOnce(&mut ViewContext<'_, V>) -> V,
1681 ) -> Self::Result<View<V>>
1682 where
1683 V: 'static + Render,
1684 {
1685 let view = self.new_view(build_view);
1686 self.window.root_view = Some(view.clone().into());
1687 self.refresh();
1688 view
1689 }
1690
1691 fn focus_view<V: crate::FocusableView>(&mut self, view: &View<V>) -> Self::Result<()> {
1692 self.update_view(view, |view, cx| {
1693 view.focus_handle(cx).clone().focus(cx);
1694 })
1695 }
1696
1697 fn dismiss_view<V>(&mut self, view: &View<V>) -> Self::Result<()>
1698 where
1699 V: ManagedView,
1700 {
1701 self.update_view(view, |_, cx| cx.emit(DismissEvent))
1702 }
1703}
1704
1705impl<'a> std::ops::Deref for WindowContext<'a> {
1706 type Target = AppContext;
1707
1708 fn deref(&self) -> &Self::Target {
1709 self.app
1710 }
1711}
1712
1713impl<'a> std::ops::DerefMut for WindowContext<'a> {
1714 fn deref_mut(&mut self) -> &mut Self::Target {
1715 self.app
1716 }
1717}
1718
1719impl<'a> Borrow<AppContext> for WindowContext<'a> {
1720 fn borrow(&self) -> &AppContext {
1721 self.app
1722 }
1723}
1724
1725impl<'a> BorrowMut<AppContext> for WindowContext<'a> {
1726 fn borrow_mut(&mut self) -> &mut AppContext {
1727 self.app
1728 }
1729}
1730
1731/// This trait contains functionality that is shared across [`ViewContext`] and [`WindowContext`]
1732pub trait BorrowWindow: BorrowMut<Window> + BorrowMut<AppContext> {
1733 #[doc(hidden)]
1734 fn app_mut(&mut self) -> &mut AppContext {
1735 self.borrow_mut()
1736 }
1737
1738 #[doc(hidden)]
1739 fn app(&self) -> &AppContext {
1740 self.borrow()
1741 }
1742
1743 #[doc(hidden)]
1744 fn window(&self) -> &Window {
1745 self.borrow()
1746 }
1747
1748 #[doc(hidden)]
1749 fn window_mut(&mut self) -> &mut Window {
1750 self.borrow_mut()
1751 }
1752}
1753
1754impl Borrow<Window> for WindowContext<'_> {
1755 fn borrow(&self) -> &Window {
1756 self.window
1757 }
1758}
1759
1760impl BorrowMut<Window> for WindowContext<'_> {
1761 fn borrow_mut(&mut self) -> &mut Window {
1762 self.window
1763 }
1764}
1765
1766impl<T> BorrowWindow for T where T: BorrowMut<AppContext> + BorrowMut<Window> {}
1767
1768/// Provides access to application state that is specialized for a particular [`View`].
1769/// Allows you to interact with focus, emit events, etc.
1770/// ViewContext also derefs to [`WindowContext`], giving you access to all of its methods as well.
1771/// When you call [`View::update`], you're passed a `&mut V` and an `&mut ViewContext<V>`.
1772pub struct ViewContext<'a, V> {
1773 window_cx: WindowContext<'a>,
1774 view: &'a View<V>,
1775}
1776
1777impl<V> Borrow<AppContext> for ViewContext<'_, V> {
1778 fn borrow(&self) -> &AppContext {
1779 &*self.window_cx.app
1780 }
1781}
1782
1783impl<V> BorrowMut<AppContext> for ViewContext<'_, V> {
1784 fn borrow_mut(&mut self) -> &mut AppContext {
1785 &mut *self.window_cx.app
1786 }
1787}
1788
1789impl<V> Borrow<Window> for ViewContext<'_, V> {
1790 fn borrow(&self) -> &Window {
1791 &*self.window_cx.window
1792 }
1793}
1794
1795impl<V> BorrowMut<Window> for ViewContext<'_, V> {
1796 fn borrow_mut(&mut self) -> &mut Window {
1797 &mut *self.window_cx.window
1798 }
1799}
1800
1801impl<'a, V: 'static> ViewContext<'a, V> {
1802 pub(crate) fn new(app: &'a mut AppContext, window: &'a mut Window, view: &'a View<V>) -> Self {
1803 Self {
1804 window_cx: WindowContext::new(app, window),
1805 view,
1806 }
1807 }
1808
1809 /// Get the entity_id of this view.
1810 pub fn entity_id(&self) -> EntityId {
1811 self.view.entity_id()
1812 }
1813
1814 /// Get the view pointer underlying this context.
1815 pub fn view(&self) -> &View<V> {
1816 self.view
1817 }
1818
1819 /// Get the model underlying this view.
1820 pub fn model(&self) -> &Model<V> {
1821 &self.view.model
1822 }
1823
1824 /// Access the underlying window context.
1825 pub fn window_context(&mut self) -> &mut WindowContext<'a> {
1826 &mut self.window_cx
1827 }
1828
1829 /// Sets a given callback to be run on the next frame.
1830 pub fn on_next_frame(&mut self, f: impl FnOnce(&mut V, &mut ViewContext<V>) + 'static)
1831 where
1832 V: 'static,
1833 {
1834 let view = self.view().clone();
1835 self.window_cx.on_next_frame(move |cx| view.update(cx, f));
1836 }
1837
1838 /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
1839 /// that are currently on the stack to be returned to the app.
1840 pub fn defer(&mut self, f: impl FnOnce(&mut V, &mut ViewContext<V>) + 'static) {
1841 let view = self.view().downgrade();
1842 self.window_cx.defer(move |cx| {
1843 view.update(cx, f).ok();
1844 });
1845 }
1846
1847 /// Observe another model or view for changes to its state, as tracked by [`ModelContext::notify`].
1848 pub fn observe<V2, E>(
1849 &mut self,
1850 entity: &E,
1851 mut on_notify: impl FnMut(&mut V, E, &mut ViewContext<'_, V>) + 'static,
1852 ) -> Subscription
1853 where
1854 V2: 'static,
1855 V: 'static,
1856 E: Entity<V2>,
1857 {
1858 let view = self.view().downgrade();
1859 let entity_id = entity.entity_id();
1860 let entity = entity.downgrade();
1861 let window_handle = self.window.handle;
1862 let (subscription, activate) = self.app.observers.insert(
1863 entity_id,
1864 Box::new(move |cx| {
1865 window_handle
1866 .update(cx, |_, cx| {
1867 if let Some(handle) = E::upgrade_from(&entity) {
1868 view.update(cx, |this, cx| on_notify(this, handle, cx))
1869 .is_ok()
1870 } else {
1871 false
1872 }
1873 })
1874 .unwrap_or(false)
1875 }),
1876 );
1877 self.app.defer(move |_| activate());
1878 subscription
1879 }
1880
1881 /// Subscribe to events emitted by another model or view.
1882 /// The entity to which you're subscribing must implement the [`EventEmitter`] trait.
1883 /// 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.
1884 pub fn subscribe<V2, E, Evt>(
1885 &mut self,
1886 entity: &E,
1887 mut on_event: impl FnMut(&mut V, E, &Evt, &mut ViewContext<'_, V>) + 'static,
1888 ) -> Subscription
1889 where
1890 V2: EventEmitter<Evt>,
1891 E: Entity<V2>,
1892 Evt: 'static,
1893 {
1894 let view = self.view().downgrade();
1895 let entity_id = entity.entity_id();
1896 let handle = entity.downgrade();
1897 let window_handle = self.window.handle;
1898 let (subscription, activate) = self.app.event_listeners.insert(
1899 entity_id,
1900 (
1901 TypeId::of::<Evt>(),
1902 Box::new(move |event, cx| {
1903 window_handle
1904 .update(cx, |_, cx| {
1905 if let Some(handle) = E::upgrade_from(&handle) {
1906 let event = event.downcast_ref().expect("invalid event type");
1907 view.update(cx, |this, cx| on_event(this, handle, event, cx))
1908 .is_ok()
1909 } else {
1910 false
1911 }
1912 })
1913 .unwrap_or(false)
1914 }),
1915 ),
1916 );
1917 self.app.defer(move |_| activate());
1918 subscription
1919 }
1920
1921 /// Register a callback to be invoked when the view is released.
1922 ///
1923 /// The callback receives a handle to the view's window. This handle may be
1924 /// invalid, if the window was closed before the view was released.
1925 pub fn on_release(
1926 &mut self,
1927 on_release: impl FnOnce(&mut V, AnyWindowHandle, &mut AppContext) + 'static,
1928 ) -> Subscription {
1929 let window_handle = self.window.handle;
1930 let (subscription, activate) = self.app.release_listeners.insert(
1931 self.view.model.entity_id,
1932 Box::new(move |this, cx| {
1933 let this = this.downcast_mut().expect("invalid entity type");
1934 on_release(this, window_handle, cx)
1935 }),
1936 );
1937 activate();
1938 subscription
1939 }
1940
1941 /// Register a callback to be invoked when the given Model or View is released.
1942 pub fn observe_release<V2, E>(
1943 &mut self,
1944 entity: &E,
1945 mut on_release: impl FnMut(&mut V, &mut V2, &mut ViewContext<'_, V>) + 'static,
1946 ) -> Subscription
1947 where
1948 V: 'static,
1949 V2: 'static,
1950 E: Entity<V2>,
1951 {
1952 let view = self.view().downgrade();
1953 let entity_id = entity.entity_id();
1954 let window_handle = self.window.handle;
1955 let (subscription, activate) = self.app.release_listeners.insert(
1956 entity_id,
1957 Box::new(move |entity, cx| {
1958 let entity = entity.downcast_mut().expect("invalid entity type");
1959 let _ = window_handle.update(cx, |_, cx| {
1960 view.update(cx, |this, cx| on_release(this, entity, cx))
1961 });
1962 }),
1963 );
1964 activate();
1965 subscription
1966 }
1967
1968 /// Indicate that this view has changed, which will invoke any observers and also mark the window as dirty.
1969 /// If this view or any of its ancestors are *cached*, notifying it will cause it or its ancestors to be redrawn.
1970 pub fn notify(&mut self) {
1971 for view_id in self
1972 .window
1973 .rendered_frame
1974 .dispatch_tree
1975 .view_path(self.view.entity_id())
1976 .into_iter()
1977 .rev()
1978 {
1979 if !self.window.dirty_views.insert(view_id) {
1980 break;
1981 }
1982 }
1983
1984 if !self.window.drawing {
1985 self.window_cx.window.dirty = true;
1986 self.window_cx.app.push_effect(Effect::Notify {
1987 emitter: self.view.model.entity_id,
1988 });
1989 }
1990 }
1991
1992 /// Register a callback to be invoked when the window is resized.
1993 pub fn observe_window_bounds(
1994 &mut self,
1995 mut callback: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
1996 ) -> Subscription {
1997 let view = self.view.downgrade();
1998 let (subscription, activate) = self.window.bounds_observers.insert(
1999 (),
2000 Box::new(move |cx| view.update(cx, |view, cx| callback(view, cx)).is_ok()),
2001 );
2002 activate();
2003 subscription
2004 }
2005
2006 /// Register a callback to be invoked when the window is activated or deactivated.
2007 pub fn observe_window_activation(
2008 &mut self,
2009 mut callback: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2010 ) -> Subscription {
2011 let view = self.view.downgrade();
2012 let (subscription, activate) = self.window.activation_observers.insert(
2013 (),
2014 Box::new(move |cx| view.update(cx, |view, cx| callback(view, cx)).is_ok()),
2015 );
2016 activate();
2017 subscription
2018 }
2019
2020 /// Register a listener to be called when the given focus handle receives focus.
2021 /// Returns a subscription and persists until the subscription is dropped.
2022 pub fn on_focus(
2023 &mut self,
2024 handle: &FocusHandle,
2025 mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2026 ) -> Subscription {
2027 let view = self.view.downgrade();
2028 let focus_id = handle.id;
2029 let (subscription, activate) = self.window.focus_listeners.insert(
2030 (),
2031 Box::new(move |event, cx| {
2032 view.update(cx, |view, cx| {
2033 if event.previous_focus_path.last() != Some(&focus_id)
2034 && event.current_focus_path.last() == Some(&focus_id)
2035 {
2036 listener(view, cx)
2037 }
2038 })
2039 .is_ok()
2040 }),
2041 );
2042 self.app.defer(move |_| activate());
2043 subscription
2044 }
2045
2046 /// Register a listener to be called when the given focus handle or one of its descendants receives focus.
2047 /// Returns a subscription and persists until the subscription is dropped.
2048 pub fn on_focus_in(
2049 &mut self,
2050 handle: &FocusHandle,
2051 mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2052 ) -> Subscription {
2053 let view = self.view.downgrade();
2054 let focus_id = handle.id;
2055 let (subscription, activate) = self.window.focus_listeners.insert(
2056 (),
2057 Box::new(move |event, cx| {
2058 view.update(cx, |view, cx| {
2059 if !event.previous_focus_path.contains(&focus_id)
2060 && event.current_focus_path.contains(&focus_id)
2061 {
2062 listener(view, cx)
2063 }
2064 })
2065 .is_ok()
2066 }),
2067 );
2068 self.app.defer(move |_| activate());
2069 subscription
2070 }
2071
2072 /// Register a listener to be called when the given focus handle loses focus.
2073 /// Returns a subscription and persists until the subscription is dropped.
2074 pub fn on_blur(
2075 &mut self,
2076 handle: &FocusHandle,
2077 mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2078 ) -> Subscription {
2079 let view = self.view.downgrade();
2080 let focus_id = handle.id;
2081 let (subscription, activate) = self.window.focus_listeners.insert(
2082 (),
2083 Box::new(move |event, cx| {
2084 view.update(cx, |view, cx| {
2085 if event.previous_focus_path.last() == Some(&focus_id)
2086 && event.current_focus_path.last() != Some(&focus_id)
2087 {
2088 listener(view, cx)
2089 }
2090 })
2091 .is_ok()
2092 }),
2093 );
2094 self.app.defer(move |_| activate());
2095 subscription
2096 }
2097
2098 /// Register a listener to be called when nothing in the window has focus.
2099 /// This typically happens when the node that was focused is removed from the tree,
2100 /// and this callback lets you chose a default place to restore the users focus.
2101 /// Returns a subscription and persists until the subscription is dropped.
2102 pub fn on_focus_lost(
2103 &mut self,
2104 mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2105 ) -> Subscription {
2106 let view = self.view.downgrade();
2107 let (subscription, activate) = self.window.focus_lost_listeners.insert(
2108 (),
2109 Box::new(move |cx| view.update(cx, |view, cx| listener(view, cx)).is_ok()),
2110 );
2111 activate();
2112 subscription
2113 }
2114
2115 /// Register a listener to be called when the given focus handle or one of its descendants loses focus.
2116 /// Returns a subscription and persists until the subscription is dropped.
2117 pub fn on_focus_out(
2118 &mut self,
2119 handle: &FocusHandle,
2120 mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2121 ) -> Subscription {
2122 let view = self.view.downgrade();
2123 let focus_id = handle.id;
2124 let (subscription, activate) = self.window.focus_listeners.insert(
2125 (),
2126 Box::new(move |event, cx| {
2127 view.update(cx, |view, cx| {
2128 if event.previous_focus_path.contains(&focus_id)
2129 && !event.current_focus_path.contains(&focus_id)
2130 {
2131 listener(view, cx)
2132 }
2133 })
2134 .is_ok()
2135 }),
2136 );
2137 self.app.defer(move |_| activate());
2138 subscription
2139 }
2140
2141 /// Schedule a future to be run asynchronously.
2142 /// The given callback is invoked with a [`WeakView<V>`] to avoid leaking the view for a long-running process.
2143 /// It's also given an [`AsyncWindowContext`], which can be used to access the state of the view across await points.
2144 /// The returned future will be polled on the main thread.
2145 pub fn spawn<Fut, R>(
2146 &mut self,
2147 f: impl FnOnce(WeakView<V>, AsyncWindowContext) -> Fut,
2148 ) -> Task<R>
2149 where
2150 R: 'static,
2151 Fut: Future<Output = R> + 'static,
2152 {
2153 let view = self.view().downgrade();
2154 self.window_cx.spawn(|cx| f(view, cx))
2155 }
2156
2157 /// Updates the global state of the given type.
2158 pub fn update_global<G, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R
2159 where
2160 G: 'static,
2161 {
2162 let mut global = self.app.lease_global::<G>();
2163 let result = f(&mut global, self);
2164 self.app.end_global_lease(global);
2165 result
2166 }
2167
2168 /// Register a callback to be invoked when the given global state changes.
2169 pub fn observe_global<G: 'static>(
2170 &mut self,
2171 mut f: impl FnMut(&mut V, &mut ViewContext<'_, V>) + 'static,
2172 ) -> Subscription {
2173 let window_handle = self.window.handle;
2174 let view = self.view().downgrade();
2175 let (subscription, activate) = self.global_observers.insert(
2176 TypeId::of::<G>(),
2177 Box::new(move |cx| {
2178 window_handle
2179 .update(cx, |_, cx| view.update(cx, |view, cx| f(view, cx)).is_ok())
2180 .unwrap_or(false)
2181 }),
2182 );
2183 self.app.defer(move |_| activate());
2184 subscription
2185 }
2186
2187 /// Register a callback to be invoked when the given Action type is dispatched to the window.
2188 pub fn on_action(
2189 &mut self,
2190 action_type: TypeId,
2191 listener: impl Fn(&mut V, &dyn Any, DispatchPhase, &mut ViewContext<V>) + 'static,
2192 ) {
2193 let handle = self.view().clone();
2194 self.window_cx
2195 .on_action(action_type, move |action, phase, cx| {
2196 handle.update(cx, |view, cx| {
2197 listener(view, action, phase, cx);
2198 })
2199 });
2200 }
2201
2202 /// Emit an event to be handled any other views that have subscribed via [ViewContext::subscribe].
2203 pub fn emit<Evt>(&mut self, event: Evt)
2204 where
2205 Evt: 'static,
2206 V: EventEmitter<Evt>,
2207 {
2208 let emitter = self.view.model.entity_id;
2209 self.app.push_effect(Effect::Emit {
2210 emitter,
2211 event_type: TypeId::of::<Evt>(),
2212 event: Box::new(event),
2213 });
2214 }
2215
2216 /// Move focus to the current view, assuming it implements [`FocusableView`].
2217 pub fn focus_self(&mut self)
2218 where
2219 V: FocusableView,
2220 {
2221 self.defer(|view, cx| view.focus_handle(cx).focus(cx))
2222 }
2223
2224 /// Convenience method for accessing view state in an event callback.
2225 ///
2226 /// Many GPUI callbacks take the form of `Fn(&E, &mut WindowContext)`,
2227 /// but it's often useful to be able to access view state in these
2228 /// callbacks. This method provides a convenient way to do so.
2229 pub fn listener<E>(
2230 &self,
2231 f: impl Fn(&mut V, &E, &mut ViewContext<V>) + 'static,
2232 ) -> impl Fn(&E, &mut WindowContext) + 'static {
2233 let view = self.view().downgrade();
2234 move |e: &E, cx: &mut WindowContext| {
2235 view.update(cx, |view, cx| f(view, e, cx)).ok();
2236 }
2237 }
2238}
2239
2240impl<V> Context for ViewContext<'_, V> {
2241 type Result<U> = U;
2242
2243 fn new_model<T: 'static>(
2244 &mut self,
2245 build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
2246 ) -> Model<T> {
2247 self.window_cx.new_model(build_model)
2248 }
2249
2250 fn update_model<T: 'static, R>(
2251 &mut self,
2252 model: &Model<T>,
2253 update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
2254 ) -> R {
2255 self.window_cx.update_model(model, update)
2256 }
2257
2258 fn update_window<T, F>(&mut self, window: AnyWindowHandle, update: F) -> Result<T>
2259 where
2260 F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
2261 {
2262 self.window_cx.update_window(window, update)
2263 }
2264
2265 fn read_model<T, R>(
2266 &self,
2267 handle: &Model<T>,
2268 read: impl FnOnce(&T, &AppContext) -> R,
2269 ) -> Self::Result<R>
2270 where
2271 T: 'static,
2272 {
2273 self.window_cx.read_model(handle, read)
2274 }
2275
2276 fn read_window<T, R>(
2277 &self,
2278 window: &WindowHandle<T>,
2279 read: impl FnOnce(View<T>, &AppContext) -> R,
2280 ) -> Result<R>
2281 where
2282 T: 'static,
2283 {
2284 self.window_cx.read_window(window, read)
2285 }
2286}
2287
2288impl<V: 'static> VisualContext for ViewContext<'_, V> {
2289 fn new_view<W: Render + 'static>(
2290 &mut self,
2291 build_view_state: impl FnOnce(&mut ViewContext<'_, W>) -> W,
2292 ) -> Self::Result<View<W>> {
2293 self.window_cx.new_view(build_view_state)
2294 }
2295
2296 fn update_view<V2: 'static, R>(
2297 &mut self,
2298 view: &View<V2>,
2299 update: impl FnOnce(&mut V2, &mut ViewContext<'_, V2>) -> R,
2300 ) -> Self::Result<R> {
2301 self.window_cx.update_view(view, update)
2302 }
2303
2304 fn replace_root_view<W>(
2305 &mut self,
2306 build_view: impl FnOnce(&mut ViewContext<'_, W>) -> W,
2307 ) -> Self::Result<View<W>>
2308 where
2309 W: 'static + Render,
2310 {
2311 self.window_cx.replace_root_view(build_view)
2312 }
2313
2314 fn focus_view<W: FocusableView>(&mut self, view: &View<W>) -> Self::Result<()> {
2315 self.window_cx.focus_view(view)
2316 }
2317
2318 fn dismiss_view<W: ManagedView>(&mut self, view: &View<W>) -> Self::Result<()> {
2319 self.window_cx.dismiss_view(view)
2320 }
2321}
2322
2323impl<'a, V> std::ops::Deref for ViewContext<'a, V> {
2324 type Target = WindowContext<'a>;
2325
2326 fn deref(&self) -> &Self::Target {
2327 &self.window_cx
2328 }
2329}
2330
2331impl<'a, V> std::ops::DerefMut for ViewContext<'a, V> {
2332 fn deref_mut(&mut self) -> &mut Self::Target {
2333 &mut self.window_cx
2334 }
2335}
2336
2337// #[derive(Clone, Copy, Eq, PartialEq, Hash)]
2338slotmap::new_key_type! {
2339 /// A unique identifier for a window.
2340 pub struct WindowId;
2341}
2342
2343impl WindowId {
2344 /// Converts this window ID to a `u64`.
2345 pub fn as_u64(&self) -> u64 {
2346 self.0.as_ffi()
2347 }
2348}
2349
2350/// A handle to a window with a specific root view type.
2351/// Note that this does not keep the window alive on its own.
2352#[derive(Deref, DerefMut)]
2353pub struct WindowHandle<V> {
2354 #[deref]
2355 #[deref_mut]
2356 pub(crate) any_handle: AnyWindowHandle,
2357 state_type: PhantomData<V>,
2358}
2359
2360impl<V: 'static + Render> WindowHandle<V> {
2361 /// Creates a new handle from a window ID.
2362 /// This does not check if the root type of the window is `V`.
2363 pub fn new(id: WindowId) -> Self {
2364 WindowHandle {
2365 any_handle: AnyWindowHandle {
2366 id,
2367 state_type: TypeId::of::<V>(),
2368 },
2369 state_type: PhantomData,
2370 }
2371 }
2372
2373 /// Get the root view out of this window.
2374 ///
2375 /// This will fail if the window is closed or if the root view's type does not match `V`.
2376 pub fn root<C>(&self, cx: &mut C) -> Result<View<V>>
2377 where
2378 C: Context,
2379 {
2380 Flatten::flatten(cx.update_window(self.any_handle, |root_view, _| {
2381 root_view
2382 .downcast::<V>()
2383 .map_err(|_| anyhow!("the type of the window's root view has changed"))
2384 }))
2385 }
2386
2387 /// Updates the root view of this window.
2388 ///
2389 /// This will fail if the window has been closed or if the root view's type does not match
2390 pub fn update<C, R>(
2391 &self,
2392 cx: &mut C,
2393 update: impl FnOnce(&mut V, &mut ViewContext<'_, V>) -> R,
2394 ) -> Result<R>
2395 where
2396 C: Context,
2397 {
2398 cx.update_window(self.any_handle, |root_view, cx| {
2399 let view = root_view
2400 .downcast::<V>()
2401 .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
2402 Ok(cx.update_view(&view, update))
2403 })?
2404 }
2405
2406 /// Read the root view out of this window.
2407 ///
2408 /// This will fail if the window is closed or if the root view's type does not match `V`.
2409 pub fn read<'a>(&self, cx: &'a AppContext) -> Result<&'a V> {
2410 let x = cx
2411 .windows
2412 .get(self.id)
2413 .and_then(|window| {
2414 window
2415 .as_ref()
2416 .and_then(|window| window.root_view.clone())
2417 .map(|root_view| root_view.downcast::<V>())
2418 })
2419 .ok_or_else(|| anyhow!("window not found"))?
2420 .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
2421
2422 Ok(x.read(cx))
2423 }
2424
2425 /// Read the root view out of this window, with a callback
2426 ///
2427 /// This will fail if the window is closed or if the root view's type does not match `V`.
2428 pub fn read_with<C, R>(&self, cx: &C, read_with: impl FnOnce(&V, &AppContext) -> R) -> Result<R>
2429 where
2430 C: Context,
2431 {
2432 cx.read_window(self, |root_view, cx| read_with(root_view.read(cx), cx))
2433 }
2434
2435 /// Read the root view pointer off of this window.
2436 ///
2437 /// This will fail if the window is closed or if the root view's type does not match `V`.
2438 pub fn root_view<C>(&self, cx: &C) -> Result<View<V>>
2439 where
2440 C: Context,
2441 {
2442 cx.read_window(self, |root_view, _cx| root_view.clone())
2443 }
2444
2445 /// Check if this window is 'active'.
2446 ///
2447 /// Will return `None` if the window is closed.
2448 pub fn is_active(&self, cx: &AppContext) -> Option<bool> {
2449 cx.windows
2450 .get(self.id)
2451 .and_then(|window| window.as_ref().map(|window| window.active))
2452 }
2453}
2454
2455impl<V> Copy for WindowHandle<V> {}
2456
2457impl<V> Clone for WindowHandle<V> {
2458 fn clone(&self) -> Self {
2459 *self
2460 }
2461}
2462
2463impl<V> PartialEq for WindowHandle<V> {
2464 fn eq(&self, other: &Self) -> bool {
2465 self.any_handle == other.any_handle
2466 }
2467}
2468
2469impl<V> Eq for WindowHandle<V> {}
2470
2471impl<V> Hash for WindowHandle<V> {
2472 fn hash<H: Hasher>(&self, state: &mut H) {
2473 self.any_handle.hash(state);
2474 }
2475}
2476
2477impl<V: 'static> From<WindowHandle<V>> for AnyWindowHandle {
2478 fn from(val: WindowHandle<V>) -> Self {
2479 val.any_handle
2480 }
2481}
2482
2483/// A handle to a window with any root view type, which can be downcast to a window with a specific root view type.
2484#[derive(Copy, Clone, PartialEq, Eq, Hash)]
2485pub struct AnyWindowHandle {
2486 pub(crate) id: WindowId,
2487 state_type: TypeId,
2488}
2489
2490impl AnyWindowHandle {
2491 /// Get the ID of this window.
2492 pub fn window_id(&self) -> WindowId {
2493 self.id
2494 }
2495
2496 /// Attempt to convert this handle to a window handle with a specific root view type.
2497 /// If the types do not match, this will return `None`.
2498 pub fn downcast<T: 'static>(&self) -> Option<WindowHandle<T>> {
2499 if TypeId::of::<T>() == self.state_type {
2500 Some(WindowHandle {
2501 any_handle: *self,
2502 state_type: PhantomData,
2503 })
2504 } else {
2505 None
2506 }
2507 }
2508
2509 /// Updates the state of the root view of this window.
2510 ///
2511 /// This will fail if the window has been closed.
2512 pub fn update<C, R>(
2513 self,
2514 cx: &mut C,
2515 update: impl FnOnce(AnyView, &mut WindowContext<'_>) -> R,
2516 ) -> Result<R>
2517 where
2518 C: Context,
2519 {
2520 cx.update_window(self, update)
2521 }
2522
2523 /// Read the state of the root view of this window.
2524 ///
2525 /// This will fail if the window has been closed.
2526 pub fn read<T, C, R>(self, cx: &C, read: impl FnOnce(View<T>, &AppContext) -> R) -> Result<R>
2527 where
2528 C: Context,
2529 T: 'static,
2530 {
2531 let view = self
2532 .downcast::<T>()
2533 .context("the type of the window's root view has changed")?;
2534
2535 cx.read_window(&view, read)
2536 }
2537}
2538
2539/// An identifier for an [`Element`](crate::Element).
2540///
2541/// Can be constructed with a string, a number, or both, as well
2542/// as other internal representations.
2543#[derive(Clone, Debug, Eq, PartialEq, Hash)]
2544pub enum ElementId {
2545 /// The ID of a View element
2546 View(EntityId),
2547 /// An integer ID.
2548 Integer(usize),
2549 /// A string based ID.
2550 Name(SharedString),
2551 /// An ID that's equated with a focus handle.
2552 FocusHandle(FocusId),
2553 /// A combination of a name and an integer.
2554 NamedInteger(SharedString, usize),
2555}
2556
2557impl Display for ElementId {
2558 fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
2559 match self {
2560 ElementId::View(entity_id) => write!(f, "view-{}", entity_id)?,
2561 ElementId::Integer(ix) => write!(f, "{}", ix)?,
2562 ElementId::Name(name) => write!(f, "{}", name)?,
2563 ElementId::FocusHandle(__) => write!(f, "FocusHandle")?,
2564 ElementId::NamedInteger(s, i) => write!(f, "{}-{}", s, i)?,
2565 }
2566
2567 Ok(())
2568 }
2569}
2570
2571impl ElementId {
2572 pub(crate) fn from_entity_id(entity_id: EntityId) -> Self {
2573 ElementId::View(entity_id)
2574 }
2575}
2576
2577impl TryInto<SharedString> for ElementId {
2578 type Error = anyhow::Error;
2579
2580 fn try_into(self) -> anyhow::Result<SharedString> {
2581 if let ElementId::Name(name) = self {
2582 Ok(name)
2583 } else {
2584 Err(anyhow!("element id is not string"))
2585 }
2586 }
2587}
2588
2589impl From<usize> for ElementId {
2590 fn from(id: usize) -> Self {
2591 ElementId::Integer(id)
2592 }
2593}
2594
2595impl From<i32> for ElementId {
2596 fn from(id: i32) -> Self {
2597 Self::Integer(id as usize)
2598 }
2599}
2600
2601impl From<SharedString> for ElementId {
2602 fn from(name: SharedString) -> Self {
2603 ElementId::Name(name)
2604 }
2605}
2606
2607impl From<&'static str> for ElementId {
2608 fn from(name: &'static str) -> Self {
2609 ElementId::Name(name.into())
2610 }
2611}
2612
2613impl<'a> From<&'a FocusHandle> for ElementId {
2614 fn from(handle: &'a FocusHandle) -> Self {
2615 ElementId::FocusHandle(handle.id)
2616 }
2617}
2618
2619impl From<(&'static str, EntityId)> for ElementId {
2620 fn from((name, id): (&'static str, EntityId)) -> Self {
2621 ElementId::NamedInteger(name.into(), id.as_u64() as usize)
2622 }
2623}
2624
2625impl From<(&'static str, usize)> for ElementId {
2626 fn from((name, id): (&'static str, usize)) -> Self {
2627 ElementId::NamedInteger(name.into(), id)
2628 }
2629}
2630
2631impl From<(&'static str, u64)> for ElementId {
2632 fn from((name, id): (&'static str, u64)) -> Self {
2633 ElementId::NamedInteger(name.into(), id as usize)
2634 }
2635}
2636
2637/// A rectangle to be rendered in the window at the given position and size.
2638/// Passed as an argument [`WindowContext::paint_quad`].
2639#[derive(Clone)]
2640pub struct PaintQuad {
2641 bounds: Bounds<Pixels>,
2642 corner_radii: Corners<Pixels>,
2643 background: Hsla,
2644 border_widths: Edges<Pixels>,
2645 border_color: Hsla,
2646}
2647
2648impl PaintQuad {
2649 /// Sets the corner radii of the quad.
2650 pub fn corner_radii(self, corner_radii: impl Into<Corners<Pixels>>) -> Self {
2651 PaintQuad {
2652 corner_radii: corner_radii.into(),
2653 ..self
2654 }
2655 }
2656
2657 /// Sets the border widths of the quad.
2658 pub fn border_widths(self, border_widths: impl Into<Edges<Pixels>>) -> Self {
2659 PaintQuad {
2660 border_widths: border_widths.into(),
2661 ..self
2662 }
2663 }
2664
2665 /// Sets the border color of the quad.
2666 pub fn border_color(self, border_color: impl Into<Hsla>) -> Self {
2667 PaintQuad {
2668 border_color: border_color.into(),
2669 ..self
2670 }
2671 }
2672
2673 /// Sets the background color of the quad.
2674 pub fn background(self, background: impl Into<Hsla>) -> Self {
2675 PaintQuad {
2676 background: background.into(),
2677 ..self
2678 }
2679 }
2680}
2681
2682/// Creates a quad with the given parameters.
2683pub fn quad(
2684 bounds: Bounds<Pixels>,
2685 corner_radii: impl Into<Corners<Pixels>>,
2686 background: impl Into<Hsla>,
2687 border_widths: impl Into<Edges<Pixels>>,
2688 border_color: impl Into<Hsla>,
2689) -> PaintQuad {
2690 PaintQuad {
2691 bounds,
2692 corner_radii: corner_radii.into(),
2693 background: background.into(),
2694 border_widths: border_widths.into(),
2695 border_color: border_color.into(),
2696 }
2697}
2698
2699/// Creates a filled quad with the given bounds and background color.
2700pub fn fill(bounds: impl Into<Bounds<Pixels>>, background: impl Into<Hsla>) -> PaintQuad {
2701 PaintQuad {
2702 bounds: bounds.into(),
2703 corner_radii: (0.).into(),
2704 background: background.into(),
2705 border_widths: (0.).into(),
2706 border_color: transparent_black(),
2707 }
2708}
2709
2710/// Creates a rectangle outline with the given bounds, border color, and a 1px border width
2711pub fn outline(bounds: impl Into<Bounds<Pixels>>, border_color: impl Into<Hsla>) -> PaintQuad {
2712 PaintQuad {
2713 bounds: bounds.into(),
2714 corner_radii: (0.).into(),
2715 background: transparent_black(),
2716 border_widths: (1.).into(),
2717 border_color: border_color.into(),
2718 }
2719}