1#![deny(missing_docs)]
2
3use crate::{
4 px, size, transparent_black, Action, AnyDrag, AnyView, AppContext, Arena, AsyncWindowContext,
5 AvailableSpace, Bounds, BoxShadow, Context, Corners, CursorStyle, DevicePixels,
6 DispatchActionListener, DispatchNodeId, DispatchTree, DisplayId, Edges, Effect, Entity,
7 EntityId, EventEmitter, FileDropEvent, Flatten, FontId, GlobalElementId, GlyphId, Hsla,
8 ImageData, InputEvent, IsZero, KeyBinding, KeyContext, KeyDownEvent, KeystrokeEvent, LayoutId,
9 Model, ModelContext, Modifiers, MonochromeSprite, MouseButton, MouseMoveEvent, MouseUpEvent,
10 Path, Pixels, PlatformAtlas, PlatformDisplay, PlatformInputHandler, PlatformWindow, Point,
11 PolychromeSprite, PromptLevel, Quad, Render, RenderGlyphParams, RenderImageParams,
12 RenderSvgParams, ScaledPixels, Scene, Shadow, SharedString, Size, Style, SubscriberSet,
13 Subscription, Surface, TaffyLayoutEngine, Task, Underline, UnderlineStyle, View, VisualContext,
14 WeakView, WindowBounds, WindowOptions, SUBPIXEL_VARIANTS,
15};
16use anyhow::{anyhow, Context as _, Result};
17use collections::{FxHashMap, FxHashSet};
18use derive_more::{Deref, DerefMut};
19use futures::{
20 channel::{mpsc, oneshot},
21 StreamExt,
22};
23use media::core_video::CVImageBuffer;
24use parking_lot::RwLock;
25use slotmap::SlotMap;
26use smallvec::SmallVec;
27use std::{
28 any::{Any, TypeId},
29 borrow::{Borrow, BorrowMut, Cow},
30 cell::RefCell,
31 collections::hash_map::Entry,
32 fmt::Debug,
33 future::Future,
34 hash::{Hash, Hasher},
35 marker::PhantomData,
36 mem,
37 rc::Rc,
38 sync::{
39 atomic::{AtomicUsize, Ordering::SeqCst},
40 Arc,
41 },
42};
43use util::{post_inc, ResultExt};
44
45const ACTIVE_DRAG_Z_INDEX: u8 = 1;
46
47/// A global stacking order, which is created by stacking successive z-index values.
48/// Each z-index will always be interpreted in the context of its parent z-index.
49#[derive(Deref, DerefMut, Clone, Ord, PartialOrd, PartialEq, Eq, Default)]
50pub struct StackingOrder {
51 #[deref]
52 #[deref_mut]
53 context_stack: SmallVec<[u8; 64]>,
54 id: u32,
55}
56
57impl std::fmt::Debug for StackingOrder {
58 fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
59 let mut stacks = self.context_stack.iter().peekable();
60 write!(f, "[({}): ", self.id)?;
61 while let Some(z_index) = stacks.next() {
62 write!(f, "{z_index}")?;
63 if stacks.peek().is_some() {
64 write!(f, "->")?;
65 }
66 }
67 write!(f, "]")?;
68 Ok(())
69 }
70}
71
72/// Represents the two different phases when dispatching events.
73#[derive(Default, Copy, Clone, Debug, Eq, PartialEq)]
74pub enum DispatchPhase {
75 /// After the capture phase comes the bubble phase, in which mouse event listeners are
76 /// invoked front to back and keyboard event listeners are invoked from the focused element
77 /// to the root of the element tree. This is the phase you'll most commonly want to use when
78 /// registering event listeners.
79 #[default]
80 Bubble,
81 /// During the initial capture phase, mouse event listeners are invoked back to front, and keyboard
82 /// listeners are invoked from the root of the tree downward toward the focused element. This phase
83 /// is used for special purposes such as clearing the "pressed" state for click events. If
84 /// you stop event propagation during this phase, you need to know what you're doing. Handlers
85 /// outside of the immediate region may rely on detecting non-local events during this phase.
86 Capture,
87}
88
89impl DispatchPhase {
90 /// Returns true if this represents the "bubble" phase.
91 pub fn bubble(self) -> bool {
92 self == DispatchPhase::Bubble
93 }
94
95 /// Returns true if this represents the "capture" phase.
96 pub fn capture(self) -> bool {
97 self == DispatchPhase::Capture
98 }
99}
100
101type AnyObserver = Box<dyn FnMut(&mut WindowContext) -> bool + 'static>;
102type AnyMouseListener = Box<dyn FnMut(&dyn Any, DispatchPhase, &mut WindowContext) + 'static>;
103type AnyWindowFocusListener = Box<dyn FnMut(&FocusEvent, &mut WindowContext) -> bool + 'static>;
104
105struct FocusEvent {
106 previous_focus_path: SmallVec<[FocusId; 8]>,
107 current_focus_path: SmallVec<[FocusId; 8]>,
108}
109
110slotmap::new_key_type! {
111 /// A globally unique identifier for a focusable element.
112 pub struct FocusId;
113}
114
115thread_local! {
116 pub(crate) static ELEMENT_ARENA: RefCell<Arena> = RefCell::new(Arena::new(4 * 1024 * 1024));
117}
118
119impl FocusId {
120 /// Obtains whether the element associated with this handle is currently focused.
121 pub fn is_focused(&self, cx: &WindowContext) -> bool {
122 cx.window.focus == Some(*self)
123 }
124
125 /// Obtains whether the element associated with this handle contains the focused
126 /// element or is itself focused.
127 pub fn contains_focused(&self, cx: &WindowContext) -> bool {
128 cx.focused()
129 .map_or(false, |focused| self.contains(focused.id, cx))
130 }
131
132 /// Obtains whether the element associated with this handle is contained within the
133 /// focused element or is itself focused.
134 pub fn within_focused(&self, cx: &WindowContext) -> bool {
135 let focused = cx.focused();
136 focused.map_or(false, |focused| focused.id.contains(*self, cx))
137 }
138
139 /// Obtains whether this handle contains the given handle in the most recently rendered frame.
140 pub(crate) fn contains(&self, other: Self, cx: &WindowContext) -> bool {
141 cx.window
142 .rendered_frame
143 .dispatch_tree
144 .focus_contains(*self, other)
145 }
146}
147
148/// A handle which can be used to track and manipulate the focused element in a window.
149pub struct FocusHandle {
150 pub(crate) id: FocusId,
151 handles: Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>,
152}
153
154impl std::fmt::Debug for FocusHandle {
155 fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
156 f.write_fmt(format_args!("FocusHandle({:?})", self.id))
157 }
158}
159
160impl FocusHandle {
161 pub(crate) fn new(handles: &Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>) -> Self {
162 let id = handles.write().insert(AtomicUsize::new(1));
163 Self {
164 id,
165 handles: handles.clone(),
166 }
167 }
168
169 pub(crate) fn for_id(
170 id: FocusId,
171 handles: &Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>,
172 ) -> Option<Self> {
173 let lock = handles.read();
174 let ref_count = lock.get(id)?;
175 if ref_count.load(SeqCst) == 0 {
176 None
177 } else {
178 ref_count.fetch_add(1, SeqCst);
179 Some(Self {
180 id,
181 handles: handles.clone(),
182 })
183 }
184 }
185
186 /// Moves the focus to the element associated with this handle.
187 pub fn focus(&self, cx: &mut WindowContext) {
188 cx.focus(self)
189 }
190
191 /// Obtains whether the element associated with this handle is currently focused.
192 pub fn is_focused(&self, cx: &WindowContext) -> bool {
193 self.id.is_focused(cx)
194 }
195
196 /// Obtains whether the element associated with this handle contains the focused
197 /// element or is itself focused.
198 pub fn contains_focused(&self, cx: &WindowContext) -> bool {
199 self.id.contains_focused(cx)
200 }
201
202 /// Obtains whether the element associated with this handle is contained within the
203 /// focused element or is itself focused.
204 pub fn within_focused(&self, cx: &WindowContext) -> bool {
205 self.id.within_focused(cx)
206 }
207
208 /// Obtains whether this handle contains the given handle in the most recently rendered frame.
209 pub fn contains(&self, other: &Self, cx: &WindowContext) -> bool {
210 self.id.contains(other.id, cx)
211 }
212}
213
214impl Clone for FocusHandle {
215 fn clone(&self) -> Self {
216 Self::for_id(self.id, &self.handles).unwrap()
217 }
218}
219
220impl PartialEq for FocusHandle {
221 fn eq(&self, other: &Self) -> bool {
222 self.id == other.id
223 }
224}
225
226impl Eq for FocusHandle {}
227
228impl Drop for FocusHandle {
229 fn drop(&mut self) {
230 self.handles
231 .read()
232 .get(self.id)
233 .unwrap()
234 .fetch_sub(1, SeqCst);
235 }
236}
237
238/// FocusableView allows users of your view to easily
239/// focus it (using cx.focus_view(view))
240pub trait FocusableView: 'static + Render {
241 /// Returns the focus handle associated with this view.
242 fn focus_handle(&self, cx: &AppContext) -> FocusHandle;
243}
244
245/// ManagedView is a view (like a Modal, Popover, Menu, etc.)
246/// where the lifecycle of the view is handled by another view.
247pub trait ManagedView: FocusableView + EventEmitter<DismissEvent> {}
248
249impl<M: FocusableView + EventEmitter<DismissEvent>> ManagedView for M {}
250
251/// Emitted by implementers of [`ManagedView`] to indicate the view should be dismissed, such as when a view is presented as a modal.
252pub struct DismissEvent;
253
254// Holds the state for a specific window.
255#[doc(hidden)]
256pub struct Window {
257 pub(crate) handle: AnyWindowHandle,
258 pub(crate) removed: bool,
259 pub(crate) platform_window: Box<dyn PlatformWindow>,
260 display_id: DisplayId,
261 sprite_atlas: Arc<dyn PlatformAtlas>,
262 rem_size: Pixels,
263 viewport_size: Size<Pixels>,
264 layout_engine: Option<TaffyLayoutEngine>,
265 pub(crate) root_view: Option<AnyView>,
266 pub(crate) element_id_stack: GlobalElementId,
267 pub(crate) rendered_frame: Frame,
268 pub(crate) next_frame: Frame,
269 pub(crate) dirty_views: FxHashSet<EntityId>,
270 pub(crate) focus_handles: Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>,
271 focus_listeners: SubscriberSet<(), AnyWindowFocusListener>,
272 focus_lost_listeners: SubscriberSet<(), AnyObserver>,
273 default_prevented: bool,
274 mouse_position: Point<Pixels>,
275 modifiers: Modifiers,
276 scale_factor: f32,
277 bounds: WindowBounds,
278 bounds_observers: SubscriberSet<(), AnyObserver>,
279 active: bool,
280 pub(crate) dirty: bool,
281 pub(crate) refreshing: bool,
282 pub(crate) drawing: bool,
283 activation_observers: SubscriberSet<(), AnyObserver>,
284 pub(crate) focus: Option<FocusId>,
285 focus_enabled: bool,
286
287 #[cfg(any(test, feature = "test-support"))]
288 pub(crate) focus_invalidated: bool,
289}
290
291pub(crate) struct ElementStateBox {
292 inner: Box<dyn Any>,
293 parent_view_id: EntityId,
294 #[cfg(debug_assertions)]
295 type_name: &'static str,
296}
297
298struct RequestedInputHandler {
299 view_id: EntityId,
300 handler: Option<Box<dyn PlatformInputHandler>>,
301}
302
303pub(crate) struct Frame {
304 focus: Option<FocusId>,
305 window_active: bool,
306 pub(crate) element_states: FxHashMap<GlobalElementId, ElementStateBox>,
307 mouse_listeners: FxHashMap<TypeId, Vec<(StackingOrder, EntityId, AnyMouseListener)>>,
308 pub(crate) dispatch_tree: DispatchTree,
309 pub(crate) scene: Scene,
310 pub(crate) depth_map: Vec<(StackingOrder, EntityId, Bounds<Pixels>)>,
311 pub(crate) z_index_stack: StackingOrder,
312 pub(crate) next_stacking_order_id: u32,
313 content_mask_stack: Vec<ContentMask<Pixels>>,
314 element_offset_stack: Vec<Point<Pixels>>,
315 requested_input_handler: Option<RequestedInputHandler>,
316 cursor_styles: FxHashMap<EntityId, CursorStyle>,
317 requested_cursor_style: Option<CursorStyle>,
318 pub(crate) view_stack: Vec<EntityId>,
319 pub(crate) reused_views: FxHashSet<EntityId>,
320}
321
322impl Frame {
323 fn new(dispatch_tree: DispatchTree) -> Self {
324 Frame {
325 focus: None,
326 window_active: false,
327 element_states: FxHashMap::default(),
328 mouse_listeners: FxHashMap::default(),
329 dispatch_tree,
330 scene: Scene::default(),
331 z_index_stack: StackingOrder::default(),
332 next_stacking_order_id: 0,
333 depth_map: Vec::new(),
334 content_mask_stack: Vec::new(),
335 element_offset_stack: Vec::new(),
336 requested_input_handler: None,
337 cursor_styles: FxHashMap::default(),
338 requested_cursor_style: None,
339 view_stack: Vec::new(),
340 reused_views: FxHashSet::default(),
341 }
342 }
343
344 fn clear(&mut self) {
345 self.element_states.clear();
346 self.mouse_listeners.values_mut().for_each(Vec::clear);
347 self.dispatch_tree.clear();
348 self.depth_map.clear();
349 self.next_stacking_order_id = 0;
350 self.reused_views.clear();
351 self.scene.clear();
352 self.requested_input_handler.take();
353 self.cursor_styles.clear();
354 self.requested_cursor_style.take();
355 debug_assert_eq!(self.view_stack.len(), 0);
356 }
357
358 fn focus_path(&self) -> SmallVec<[FocusId; 8]> {
359 self.focus
360 .map(|focus_id| self.dispatch_tree.focus_path(focus_id))
361 .unwrap_or_default()
362 }
363
364 fn finish(&mut self, prev_frame: &mut Self) {
365 // Reuse mouse listeners that didn't change since the last frame.
366 for (type_id, listeners) in &mut prev_frame.mouse_listeners {
367 let next_listeners = self.mouse_listeners.entry(*type_id).or_default();
368 for (order, view_id, listener) in listeners.drain(..) {
369 if self.reused_views.contains(&view_id) {
370 next_listeners.push((order, view_id, listener));
371 }
372 }
373 }
374
375 // Reuse entries in the depth map that didn't change since the last frame.
376 for (order, view_id, bounds) in prev_frame.depth_map.drain(..) {
377 if self.reused_views.contains(&view_id) {
378 match self
379 .depth_map
380 .binary_search_by(|(level, _, _)| order.cmp(level))
381 {
382 Ok(i) | Err(i) => self.depth_map.insert(i, (order, view_id, bounds)),
383 }
384 }
385 }
386
387 // Retain element states for views that didn't change since the last frame.
388 for (element_id, state) in prev_frame.element_states.drain() {
389 if self.reused_views.contains(&state.parent_view_id) {
390 self.element_states.entry(element_id).or_insert(state);
391 }
392 }
393
394 // Reuse geometry that didn't change since the last frame.
395 self.scene
396 .reuse_views(&self.reused_views, &mut prev_frame.scene);
397 self.scene.finish();
398 }
399}
400
401impl Window {
402 pub(crate) fn new(
403 handle: AnyWindowHandle,
404 options: WindowOptions,
405 cx: &mut AppContext,
406 ) -> Self {
407 let platform_window = cx.platform.open_window(handle, options);
408 let display_id = platform_window.display().id();
409 let sprite_atlas = platform_window.sprite_atlas();
410 let mouse_position = platform_window.mouse_position();
411 let modifiers = platform_window.modifiers();
412 let content_size = platform_window.content_size();
413 let scale_factor = platform_window.scale_factor();
414 let bounds = platform_window.bounds();
415
416 platform_window.on_request_frame(Box::new({
417 let mut cx = cx.to_async();
418 move || {
419 handle.update(&mut cx, |_, cx| cx.draw()).log_err();
420 }
421 }));
422 platform_window.on_resize(Box::new({
423 let mut cx = cx.to_async();
424 move |_, _| {
425 handle
426 .update(&mut cx, |_, cx| cx.window_bounds_changed())
427 .log_err();
428 }
429 }));
430 platform_window.on_moved(Box::new({
431 let mut cx = cx.to_async();
432 move || {
433 handle
434 .update(&mut cx, |_, cx| cx.window_bounds_changed())
435 .log_err();
436 }
437 }));
438 platform_window.on_active_status_change(Box::new({
439 let mut cx = cx.to_async();
440 move |active| {
441 handle
442 .update(&mut cx, |_, cx| {
443 cx.window.active = active;
444 cx.window
445 .activation_observers
446 .clone()
447 .retain(&(), |callback| callback(cx));
448 })
449 .log_err();
450 }
451 }));
452
453 platform_window.on_input({
454 let mut cx = cx.to_async();
455 Box::new(move |event| {
456 handle
457 .update(&mut cx, |_, cx| cx.dispatch_event(event))
458 .log_err()
459 .unwrap_or(false)
460 })
461 });
462
463 Window {
464 handle,
465 removed: false,
466 platform_window,
467 display_id,
468 sprite_atlas,
469 rem_size: px(16.),
470 viewport_size: content_size,
471 layout_engine: Some(TaffyLayoutEngine::new()),
472 root_view: None,
473 element_id_stack: GlobalElementId::default(),
474 rendered_frame: Frame::new(DispatchTree::new(cx.keymap.clone(), cx.actions.clone())),
475 next_frame: Frame::new(DispatchTree::new(cx.keymap.clone(), cx.actions.clone())),
476 dirty_views: FxHashSet::default(),
477 focus_handles: Arc::new(RwLock::new(SlotMap::with_key())),
478 focus_listeners: SubscriberSet::new(),
479 focus_lost_listeners: SubscriberSet::new(),
480 default_prevented: true,
481 mouse_position,
482 modifiers,
483 scale_factor,
484 bounds,
485 bounds_observers: SubscriberSet::new(),
486 active: false,
487 dirty: false,
488 refreshing: false,
489 drawing: false,
490 activation_observers: SubscriberSet::new(),
491 focus: None,
492 focus_enabled: true,
493
494 #[cfg(any(test, feature = "test-support"))]
495 focus_invalidated: false,
496 }
497 }
498}
499
500/// Indicates which region of the window is visible. Content falling outside of this mask will not be
501/// rendered. Currently, only rectangular content masks are supported, but we give the mask its own type
502/// to leave room to support more complex shapes in the future.
503#[derive(Clone, Debug, Default, PartialEq, Eq)]
504#[repr(C)]
505pub struct ContentMask<P: Clone + Default + Debug> {
506 /// The bounds
507 pub bounds: Bounds<P>,
508}
509
510impl ContentMask<Pixels> {
511 /// Scale the content mask's pixel units by the given scaling factor.
512 pub fn scale(&self, factor: f32) -> ContentMask<ScaledPixels> {
513 ContentMask {
514 bounds: self.bounds.scale(factor),
515 }
516 }
517
518 /// Intersect the content mask with the given content mask.
519 pub fn intersect(&self, other: &Self) -> Self {
520 let bounds = self.bounds.intersect(&other.bounds);
521 ContentMask { bounds }
522 }
523}
524
525/// Provides access to application state in the context of a single window. Derefs
526/// to an [`AppContext`], so you can also pass a [`WindowContext`] to any method that takes
527/// an [`AppContext`] and call any [`AppContext`] methods.
528pub struct WindowContext<'a> {
529 pub(crate) app: &'a mut AppContext,
530 pub(crate) window: &'a mut Window,
531}
532
533impl<'a> WindowContext<'a> {
534 pub(crate) fn new(app: &'a mut AppContext, window: &'a mut Window) -> Self {
535 Self { app, window }
536 }
537
538 /// Obtain a handle to the window that belongs to this context.
539 pub fn window_handle(&self) -> AnyWindowHandle {
540 self.window.handle
541 }
542
543 /// Mark the window as dirty, scheduling it to be redrawn on the next frame.
544 pub fn refresh(&mut self) {
545 if !self.window.drawing {
546 self.window.refreshing = true;
547 self.window.dirty = true;
548 }
549 }
550
551 /// Close this window.
552 pub fn remove_window(&mut self) {
553 self.window.removed = true;
554 }
555
556 /// Obtain a new [`FocusHandle`], which allows you to track and manipulate the keyboard focus
557 /// for elements rendered within this window.
558 pub fn focus_handle(&mut self) -> FocusHandle {
559 FocusHandle::new(&self.window.focus_handles)
560 }
561
562 /// Obtain the currently focused [`FocusHandle`]. If no elements are focused, returns `None`.
563 pub fn focused(&self) -> Option<FocusHandle> {
564 self.window
565 .focus
566 .and_then(|id| FocusHandle::for_id(id, &self.window.focus_handles))
567 }
568
569 /// Move focus to the element associated with the given [`FocusHandle`].
570 pub fn focus(&mut self, handle: &FocusHandle) {
571 if !self.window.focus_enabled || self.window.focus == Some(handle.id) {
572 return;
573 }
574
575 self.window.focus = Some(handle.id);
576 self.window
577 .rendered_frame
578 .dispatch_tree
579 .clear_pending_keystrokes();
580
581 #[cfg(any(test, feature = "test-support"))]
582 {
583 self.window.focus_invalidated = true;
584 }
585
586 self.refresh();
587 }
588
589 /// Remove focus from all elements within this context's window.
590 pub fn blur(&mut self) {
591 if !self.window.focus_enabled {
592 return;
593 }
594
595 self.window.focus = None;
596 self.refresh();
597 }
598
599 /// Blur the window and don't allow anything in it to be focused again.
600 pub fn disable_focus(&mut self) {
601 self.blur();
602 self.window.focus_enabled = false;
603 }
604
605 /// Dispatch the given action on the currently focused element.
606 pub fn dispatch_action(&mut self, action: Box<dyn Action>) {
607 let focus_handle = self.focused();
608
609 self.defer(move |cx| {
610 let node_id = focus_handle
611 .and_then(|handle| {
612 cx.window
613 .rendered_frame
614 .dispatch_tree
615 .focusable_node_id(handle.id)
616 })
617 .unwrap_or_else(|| cx.window.rendered_frame.dispatch_tree.root_node_id());
618
619 cx.propagate_event = true;
620 cx.dispatch_action_on_node(node_id, action);
621 })
622 }
623
624 pub(crate) fn dispatch_keystroke_observers(
625 &mut self,
626 event: &dyn Any,
627 action: Option<Box<dyn Action>>,
628 ) {
629 let Some(key_down_event) = event.downcast_ref::<KeyDownEvent>() else {
630 return;
631 };
632
633 self.keystroke_observers
634 .clone()
635 .retain(&(), move |callback| {
636 (callback)(
637 &KeystrokeEvent {
638 keystroke: key_down_event.keystroke.clone(),
639 action: action.as_ref().map(|action| action.boxed_clone()),
640 },
641 self,
642 );
643 true
644 });
645 }
646
647 pub(crate) fn clear_pending_keystrokes(&mut self) {
648 self.window
649 .rendered_frame
650 .dispatch_tree
651 .clear_pending_keystrokes();
652 self.window
653 .next_frame
654 .dispatch_tree
655 .clear_pending_keystrokes();
656 }
657
658 /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
659 /// that are currently on the stack to be returned to the app.
660 pub fn defer(&mut self, f: impl FnOnce(&mut WindowContext) + 'static) {
661 let handle = self.window.handle;
662 self.app.defer(move |cx| {
663 handle.update(cx, |_, cx| f(cx)).ok();
664 });
665 }
666
667 /// Subscribe to events emitted by a model or view.
668 /// The entity to which you're subscribing must implement the [`EventEmitter`] trait.
669 /// 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.
670 pub fn subscribe<Emitter, E, Evt>(
671 &mut self,
672 entity: &E,
673 mut on_event: impl FnMut(E, &Evt, &mut WindowContext<'_>) + 'static,
674 ) -> Subscription
675 where
676 Emitter: EventEmitter<Evt>,
677 E: Entity<Emitter>,
678 Evt: 'static,
679 {
680 let entity_id = entity.entity_id();
681 let entity = entity.downgrade();
682 let window_handle = self.window.handle;
683 let (subscription, activate) = self.app.event_listeners.insert(
684 entity_id,
685 (
686 TypeId::of::<Evt>(),
687 Box::new(move |event, cx| {
688 window_handle
689 .update(cx, |_, cx| {
690 if let Some(handle) = E::upgrade_from(&entity) {
691 let event = event.downcast_ref().expect("invalid event type");
692 on_event(handle, event, cx);
693 true
694 } else {
695 false
696 }
697 })
698 .unwrap_or(false)
699 }),
700 ),
701 );
702 self.app.defer(move |_| activate());
703 subscription
704 }
705
706 /// Create an `AsyncWindowContext`, which has a static lifetime and can be held across
707 /// await points in async code.
708 pub fn to_async(&self) -> AsyncWindowContext {
709 AsyncWindowContext::new(self.app.to_async(), self.window.handle)
710 }
711
712 /// Schedule the given closure to be run directly after the current frame is rendered.
713 pub fn on_next_frame(&mut self, callback: impl FnOnce(&mut WindowContext) + 'static) {
714 let handle = self.window.handle;
715 let display_id = self.window.display_id;
716
717 let mut frame_consumers = std::mem::take(&mut self.app.frame_consumers);
718 if let Entry::Vacant(e) = frame_consumers.entry(display_id) {
719 let (tx, mut rx) = mpsc::unbounded::<()>();
720 self.platform.set_display_link_output_callback(
721 display_id,
722 Box::new(move |_current_time, _output_time| _ = tx.unbounded_send(())),
723 );
724
725 let consumer_task = self.app.spawn(|cx| async move {
726 while rx.next().await.is_some() {
727 cx.update(|cx| {
728 for callback in cx
729 .next_frame_callbacks
730 .get_mut(&display_id)
731 .unwrap()
732 .drain(..)
733 .collect::<SmallVec<[_; 32]>>()
734 {
735 callback(cx);
736 }
737 })
738 .ok();
739
740 // Flush effects, then stop the display link if no new next_frame_callbacks have been added.
741
742 cx.update(|cx| {
743 if cx.next_frame_callbacks.is_empty() {
744 cx.platform.stop_display_link(display_id);
745 }
746 })
747 .ok();
748 }
749 });
750 e.insert(consumer_task);
751 }
752 debug_assert!(self.app.frame_consumers.is_empty());
753 self.app.frame_consumers = frame_consumers;
754
755 if self.next_frame_callbacks.is_empty() {
756 self.platform.start_display_link(display_id);
757 }
758
759 self.next_frame_callbacks
760 .entry(display_id)
761 .or_default()
762 .push(Box::new(move |cx: &mut AppContext| {
763 cx.update_window(handle, |_root_view, cx| callback(cx)).ok();
764 }));
765 }
766
767 /// Spawn the future returned by the given closure on the application thread pool.
768 /// The closure is provided a handle to the current window and an `AsyncWindowContext` for
769 /// use within your future.
770 pub fn spawn<Fut, R>(&mut self, f: impl FnOnce(AsyncWindowContext) -> Fut) -> Task<R>
771 where
772 R: 'static,
773 Fut: Future<Output = R> + 'static,
774 {
775 self.app
776 .spawn(|app| f(AsyncWindowContext::new(app, self.window.handle)))
777 }
778
779 /// Update the global of the given type. The given closure is given simultaneous mutable
780 /// access both to the global and the context.
781 pub fn update_global<G, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R
782 where
783 G: 'static,
784 {
785 let mut global = self.app.lease_global::<G>();
786 let result = f(&mut global, self);
787 self.app.end_global_lease(global);
788 result
789 }
790
791 #[must_use]
792 /// Add a node to the layout tree for the current frame. Takes the `Style` of the element for which
793 /// layout is being requested, along with the layout ids of any children. This method is called during
794 /// calls to the `Element::layout` trait method and enables any element to participate in layout.
795 pub fn request_layout(
796 &mut self,
797 style: &Style,
798 children: impl IntoIterator<Item = LayoutId>,
799 ) -> LayoutId {
800 self.app.layout_id_buffer.clear();
801 self.app.layout_id_buffer.extend(children);
802 let rem_size = self.rem_size();
803
804 self.window.layout_engine.as_mut().unwrap().request_layout(
805 style,
806 rem_size,
807 &self.app.layout_id_buffer,
808 )
809 }
810
811 /// Add a node to the layout tree for the current frame. Instead of taking a `Style` and children,
812 /// this variant takes a function that is invoked during layout so you can use arbitrary logic to
813 /// determine the element's size. One place this is used internally is when measuring text.
814 ///
815 /// The given closure is invoked at layout time with the known dimensions and available space and
816 /// returns a `Size`.
817 pub fn request_measured_layout<
818 F: FnMut(Size<Option<Pixels>>, Size<AvailableSpace>, &mut WindowContext) -> Size<Pixels>
819 + 'static,
820 >(
821 &mut self,
822 style: Style,
823 measure: F,
824 ) -> LayoutId {
825 let rem_size = self.rem_size();
826 self.window
827 .layout_engine
828 .as_mut()
829 .unwrap()
830 .request_measured_layout(style, rem_size, measure)
831 }
832
833 pub(crate) fn layout_style(&self, layout_id: LayoutId) -> Option<&Style> {
834 self.window
835 .layout_engine
836 .as_ref()
837 .unwrap()
838 .requested_style(layout_id)
839 }
840
841 /// Compute the layout for the given id within the given available space.
842 /// This method is called for its side effect, typically by the framework prior to painting.
843 /// After calling it, you can request the bounds of the given layout node id or any descendant.
844 pub fn compute_layout(&mut self, layout_id: LayoutId, available_space: Size<AvailableSpace>) {
845 let mut layout_engine = self.window.layout_engine.take().unwrap();
846 layout_engine.compute_layout(layout_id, available_space, self);
847 self.window.layout_engine = Some(layout_engine);
848 }
849
850 /// Obtain the bounds computed for the given LayoutId relative to the window. This method should not
851 /// be invoked until the paint phase begins, and will usually be invoked by GPUI itself automatically
852 /// in order to pass your element its `Bounds` automatically.
853 pub fn layout_bounds(&mut self, layout_id: LayoutId) -> Bounds<Pixels> {
854 let mut bounds = self
855 .window
856 .layout_engine
857 .as_mut()
858 .unwrap()
859 .layout_bounds(layout_id)
860 .map(Into::into);
861 bounds.origin += self.element_offset();
862 bounds
863 }
864
865 fn window_bounds_changed(&mut self) {
866 self.window.scale_factor = self.window.platform_window.scale_factor();
867 self.window.viewport_size = self.window.platform_window.content_size();
868 self.window.bounds = self.window.platform_window.bounds();
869 self.window.display_id = self.window.platform_window.display().id();
870 self.refresh();
871
872 self.window
873 .bounds_observers
874 .clone()
875 .retain(&(), |callback| callback(self));
876 }
877
878 /// Returns the bounds of the current window in the global coordinate space, which could span across multiple displays.
879 pub fn window_bounds(&self) -> WindowBounds {
880 self.window.bounds
881 }
882
883 /// Returns the size of the drawable area within the window.
884 pub fn viewport_size(&self) -> Size<Pixels> {
885 self.window.viewport_size
886 }
887
888 /// Returns whether this window is focused by the operating system (receiving key events).
889 pub fn is_window_active(&self) -> bool {
890 self.window.active
891 }
892
893 /// Toggle zoom on the window.
894 pub fn zoom_window(&self) {
895 self.window.platform_window.zoom();
896 }
897
898 /// Update the window's title at the platform level.
899 pub fn set_window_title(&mut self, title: &str) {
900 self.window.platform_window.set_title(title);
901 }
902
903 /// Mark the window as dirty at the platform level.
904 pub fn set_window_edited(&mut self, edited: bool) {
905 self.window.platform_window.set_edited(edited);
906 }
907
908 /// Determine the display on which the window is visible.
909 pub fn display(&self) -> Option<Rc<dyn PlatformDisplay>> {
910 self.platform
911 .displays()
912 .into_iter()
913 .find(|display| display.id() == self.window.display_id)
914 }
915
916 /// Show the platform character palette.
917 pub fn show_character_palette(&self) {
918 self.window.platform_window.show_character_palette();
919 }
920
921 /// The scale factor of the display associated with the window. For example, it could
922 /// return 2.0 for a "retina" display, indicating that each logical pixel should actually
923 /// be rendered as two pixels on screen.
924 pub fn scale_factor(&self) -> f32 {
925 self.window.scale_factor
926 }
927
928 /// The size of an em for the base font of the application. Adjusting this value allows the
929 /// UI to scale, just like zooming a web page.
930 pub fn rem_size(&self) -> Pixels {
931 self.window.rem_size
932 }
933
934 /// Sets the size of an em for the base font of the application. Adjusting this value allows the
935 /// UI to scale, just like zooming a web page.
936 pub fn set_rem_size(&mut self, rem_size: impl Into<Pixels>) {
937 self.window.rem_size = rem_size.into();
938 }
939
940 /// The line height associated with the current text style.
941 pub fn line_height(&self) -> Pixels {
942 let rem_size = self.rem_size();
943 let text_style = self.text_style();
944 text_style
945 .line_height
946 .to_pixels(text_style.font_size, rem_size)
947 }
948
949 /// Call to prevent the default action of an event. Currently only used to prevent
950 /// parent elements from becoming focused on mouse down.
951 pub fn prevent_default(&mut self) {
952 self.window.default_prevented = true;
953 }
954
955 /// Obtain whether default has been prevented for the event currently being dispatched.
956 pub fn default_prevented(&self) -> bool {
957 self.window.default_prevented
958 }
959
960 /// Register a mouse event listener on the window for the next frame. The type of event
961 /// is determined by the first parameter of the given listener. When the next frame is rendered
962 /// the listener will be cleared.
963 pub fn on_mouse_event<Event: 'static>(
964 &mut self,
965 mut handler: impl FnMut(&Event, DispatchPhase, &mut WindowContext) + 'static,
966 ) {
967 let view_id = self.parent_view_id();
968 let order = self.window.next_frame.z_index_stack.clone();
969 self.window
970 .next_frame
971 .mouse_listeners
972 .entry(TypeId::of::<Event>())
973 .or_default()
974 .push((
975 order,
976 view_id,
977 Box::new(
978 move |event: &dyn Any, phase: DispatchPhase, cx: &mut WindowContext<'_>| {
979 handler(event.downcast_ref().unwrap(), phase, cx)
980 },
981 ),
982 ))
983 }
984
985 /// Register a key event listener on the window for the next frame. The type of event
986 /// is determined by the first parameter of the given listener. When the next frame is rendered
987 /// the listener will be cleared.
988 ///
989 /// This is a fairly low-level method, so prefer using event handlers on elements unless you have
990 /// a specific need to register a global listener.
991 pub fn on_key_event<Event: 'static>(
992 &mut self,
993 listener: impl Fn(&Event, DispatchPhase, &mut WindowContext) + 'static,
994 ) {
995 self.window.next_frame.dispatch_tree.on_key_event(Rc::new(
996 move |event: &dyn Any, phase, cx: &mut WindowContext<'_>| {
997 if let Some(event) = event.downcast_ref::<Event>() {
998 listener(event, phase, cx)
999 }
1000 },
1001 ));
1002 }
1003
1004 /// Register an action listener on the window for the next frame. The type of action
1005 /// is determined by the first parameter of the given listener. When the next frame is rendered
1006 /// the listener will be cleared.
1007 ///
1008 /// This is a fairly low-level method, so prefer using action handlers on elements unless you have
1009 /// a specific need to register a global listener.
1010 pub fn on_action(
1011 &mut self,
1012 action_type: TypeId,
1013 listener: impl Fn(&dyn Any, DispatchPhase, &mut WindowContext) + 'static,
1014 ) {
1015 self.window
1016 .next_frame
1017 .dispatch_tree
1018 .on_action(action_type, Rc::new(listener));
1019 }
1020
1021 /// Determine whether the given action is available along the dispatch path to the currently focused element.
1022 pub fn is_action_available(&self, action: &dyn Action) -> bool {
1023 let target = self
1024 .focused()
1025 .and_then(|focused_handle| {
1026 self.window
1027 .rendered_frame
1028 .dispatch_tree
1029 .focusable_node_id(focused_handle.id)
1030 })
1031 .unwrap_or_else(|| self.window.rendered_frame.dispatch_tree.root_node_id());
1032 self.window
1033 .rendered_frame
1034 .dispatch_tree
1035 .is_action_available(action, target)
1036 }
1037
1038 /// The position of the mouse relative to the window.
1039 pub fn mouse_position(&self) -> Point<Pixels> {
1040 self.window.mouse_position
1041 }
1042
1043 /// The current state of the keyboard's modifiers
1044 pub fn modifiers(&self) -> Modifiers {
1045 self.window.modifiers
1046 }
1047
1048 /// Update the cursor style at the platform level.
1049 pub fn set_cursor_style(&mut self, style: CursorStyle) {
1050 let view_id = self.parent_view_id();
1051 self.window.next_frame.cursor_styles.insert(view_id, style);
1052 self.window.next_frame.requested_cursor_style = Some(style);
1053 }
1054
1055 /// Called during painting to track which z-index is on top at each pixel position
1056 pub fn add_opaque_layer(&mut self, bounds: Bounds<Pixels>) {
1057 let stacking_order = self.window.next_frame.z_index_stack.clone();
1058 let view_id = self.parent_view_id();
1059 let depth_map = &mut self.window.next_frame.depth_map;
1060 match depth_map.binary_search_by(|(level, _, _)| stacking_order.cmp(level)) {
1061 Ok(i) | Err(i) => depth_map.insert(i, (stacking_order, view_id, bounds)),
1062 }
1063 }
1064
1065 /// Returns true if there is no opaque layer containing the given point
1066 /// on top of the given level. Layers whose level is an extension of the
1067 /// level are not considered to be on top of the level.
1068 pub fn was_top_layer(&self, point: &Point<Pixels>, level: &StackingOrder) -> bool {
1069 for (opaque_level, _, bounds) in self.window.rendered_frame.depth_map.iter() {
1070 if level >= opaque_level {
1071 break;
1072 }
1073
1074 if bounds.contains(point) && !opaque_level.starts_with(level) {
1075 return false;
1076 }
1077 }
1078 true
1079 }
1080
1081 pub(crate) fn was_top_layer_under_active_drag(
1082 &self,
1083 point: &Point<Pixels>,
1084 level: &StackingOrder,
1085 ) -> bool {
1086 for (opaque_level, _, bounds) in self.window.rendered_frame.depth_map.iter() {
1087 if level >= opaque_level {
1088 break;
1089 }
1090 if opaque_level.starts_with(&[ACTIVE_DRAG_Z_INDEX]) {
1091 continue;
1092 }
1093
1094 if bounds.contains(point) && !opaque_level.starts_with(level) {
1095 return false;
1096 }
1097 }
1098 true
1099 }
1100
1101 /// Called during painting to get the current stacking order.
1102 pub fn stacking_order(&self) -> &StackingOrder {
1103 &self.window.next_frame.z_index_stack
1104 }
1105
1106 /// Paint one or more drop shadows into the scene for the next frame at the current z-index.
1107 pub fn paint_shadows(
1108 &mut self,
1109 bounds: Bounds<Pixels>,
1110 corner_radii: Corners<Pixels>,
1111 shadows: &[BoxShadow],
1112 ) {
1113 let scale_factor = self.scale_factor();
1114 let content_mask = self.content_mask();
1115 let view_id = self.parent_view_id();
1116 let window = &mut *self.window;
1117 for shadow in shadows {
1118 let mut shadow_bounds = bounds;
1119 shadow_bounds.origin += shadow.offset;
1120 shadow_bounds.dilate(shadow.spread_radius);
1121 window.next_frame.scene.insert(
1122 &window.next_frame.z_index_stack,
1123 Shadow {
1124 view_id: view_id.into(),
1125 layer_id: 0,
1126 order: 0,
1127 bounds: shadow_bounds.scale(scale_factor),
1128 content_mask: content_mask.scale(scale_factor),
1129 corner_radii: corner_radii.scale(scale_factor),
1130 color: shadow.color,
1131 blur_radius: shadow.blur_radius.scale(scale_factor),
1132 },
1133 );
1134 }
1135 }
1136
1137 /// Paint one or more quads into the scene for the next frame at the current stacking context.
1138 /// Quads are colored rectangular regions with an optional background, border, and corner radius.
1139 /// see [`fill`], [`outline`], and [`quad`] to construct this type.
1140 pub fn paint_quad(&mut self, quad: PaintQuad) {
1141 let scale_factor = self.scale_factor();
1142 let content_mask = self.content_mask();
1143 let view_id = self.parent_view_id();
1144
1145 let window = &mut *self.window;
1146 window.next_frame.scene.insert(
1147 &window.next_frame.z_index_stack,
1148 Quad {
1149 view_id: view_id.into(),
1150 layer_id: 0,
1151 order: 0,
1152 bounds: quad.bounds.scale(scale_factor),
1153 content_mask: content_mask.scale(scale_factor),
1154 background: quad.background,
1155 border_color: quad.border_color,
1156 corner_radii: quad.corner_radii.scale(scale_factor),
1157 border_widths: quad.border_widths.scale(scale_factor),
1158 },
1159 );
1160 }
1161
1162 /// Paint the given `Path` into the scene for the next frame at the current z-index.
1163 pub fn paint_path(&mut self, mut path: Path<Pixels>, color: impl Into<Hsla>) {
1164 let scale_factor = self.scale_factor();
1165 let content_mask = self.content_mask();
1166 let view_id = self.parent_view_id();
1167
1168 path.content_mask = content_mask;
1169 path.color = color.into();
1170 path.view_id = view_id.into();
1171 let window = &mut *self.window;
1172 window
1173 .next_frame
1174 .scene
1175 .insert(&window.next_frame.z_index_stack, path.scale(scale_factor));
1176 }
1177
1178 /// Paint an underline into the scene for the next frame at the current z-index.
1179 pub fn paint_underline(
1180 &mut self,
1181 origin: Point<Pixels>,
1182 width: Pixels,
1183 style: &UnderlineStyle,
1184 ) {
1185 let scale_factor = self.scale_factor();
1186 let height = if style.wavy {
1187 style.thickness * 3.
1188 } else {
1189 style.thickness
1190 };
1191 let bounds = Bounds {
1192 origin,
1193 size: size(width, height),
1194 };
1195 let content_mask = self.content_mask();
1196 let view_id = self.parent_view_id();
1197
1198 let window = &mut *self.window;
1199 window.next_frame.scene.insert(
1200 &window.next_frame.z_index_stack,
1201 Underline {
1202 view_id: view_id.into(),
1203 layer_id: 0,
1204 order: 0,
1205 bounds: bounds.scale(scale_factor),
1206 content_mask: content_mask.scale(scale_factor),
1207 thickness: style.thickness.scale(scale_factor),
1208 color: style.color.unwrap_or_default(),
1209 wavy: style.wavy,
1210 },
1211 );
1212 }
1213
1214 /// Paint a monochrome (non-emoji) glyph into the scene for the next frame at the current z-index.
1215 /// The y component of the origin is the baseline of the glyph.
1216 pub fn paint_glyph(
1217 &mut self,
1218 origin: Point<Pixels>,
1219 font_id: FontId,
1220 glyph_id: GlyphId,
1221 font_size: Pixels,
1222 color: Hsla,
1223 ) -> Result<()> {
1224 let scale_factor = self.scale_factor();
1225 let glyph_origin = origin.scale(scale_factor);
1226 let subpixel_variant = Point {
1227 x: (glyph_origin.x.0.fract() * SUBPIXEL_VARIANTS as f32).floor() as u8,
1228 y: (glyph_origin.y.0.fract() * SUBPIXEL_VARIANTS as f32).floor() as u8,
1229 };
1230 let params = RenderGlyphParams {
1231 font_id,
1232 glyph_id,
1233 font_size,
1234 subpixel_variant,
1235 scale_factor,
1236 is_emoji: false,
1237 };
1238
1239 let raster_bounds = self.text_system().raster_bounds(¶ms)?;
1240 if !raster_bounds.is_zero() {
1241 let tile =
1242 self.window
1243 .sprite_atlas
1244 .get_or_insert_with(¶ms.clone().into(), &mut || {
1245 let (size, bytes) = self.text_system().rasterize_glyph(¶ms)?;
1246 Ok((size, Cow::Owned(bytes)))
1247 })?;
1248 let bounds = Bounds {
1249 origin: glyph_origin.map(|px| px.floor()) + raster_bounds.origin.map(Into::into),
1250 size: tile.bounds.size.map(Into::into),
1251 };
1252 let content_mask = self.content_mask().scale(scale_factor);
1253 let view_id = self.parent_view_id();
1254 let window = &mut *self.window;
1255 window.next_frame.scene.insert(
1256 &window.next_frame.z_index_stack,
1257 MonochromeSprite {
1258 view_id: view_id.into(),
1259 layer_id: 0,
1260 order: 0,
1261 bounds,
1262 content_mask,
1263 color,
1264 tile,
1265 },
1266 );
1267 }
1268 Ok(())
1269 }
1270
1271 /// Paint an emoji glyph into the scene for the next frame at the current z-index.
1272 /// The y component of the origin is the baseline of the glyph.
1273 pub fn paint_emoji(
1274 &mut self,
1275 origin: Point<Pixels>,
1276 font_id: FontId,
1277 glyph_id: GlyphId,
1278 font_size: Pixels,
1279 ) -> Result<()> {
1280 let scale_factor = self.scale_factor();
1281 let glyph_origin = origin.scale(scale_factor);
1282 let params = RenderGlyphParams {
1283 font_id,
1284 glyph_id,
1285 font_size,
1286 // We don't render emojis with subpixel variants.
1287 subpixel_variant: Default::default(),
1288 scale_factor,
1289 is_emoji: true,
1290 };
1291
1292 let raster_bounds = self.text_system().raster_bounds(¶ms)?;
1293 if !raster_bounds.is_zero() {
1294 let tile =
1295 self.window
1296 .sprite_atlas
1297 .get_or_insert_with(¶ms.clone().into(), &mut || {
1298 let (size, bytes) = self.text_system().rasterize_glyph(¶ms)?;
1299 Ok((size, Cow::Owned(bytes)))
1300 })?;
1301 let bounds = Bounds {
1302 origin: glyph_origin.map(|px| px.floor()) + raster_bounds.origin.map(Into::into),
1303 size: tile.bounds.size.map(Into::into),
1304 };
1305 let content_mask = self.content_mask().scale(scale_factor);
1306 let view_id = self.parent_view_id();
1307 let window = &mut *self.window;
1308
1309 window.next_frame.scene.insert(
1310 &window.next_frame.z_index_stack,
1311 PolychromeSprite {
1312 view_id: view_id.into(),
1313 layer_id: 0,
1314 order: 0,
1315 bounds,
1316 corner_radii: Default::default(),
1317 content_mask,
1318 tile,
1319 grayscale: false,
1320 },
1321 );
1322 }
1323 Ok(())
1324 }
1325
1326 /// Paint a monochrome SVG into the scene for the next frame at the current stacking context.
1327 pub fn paint_svg(
1328 &mut self,
1329 bounds: Bounds<Pixels>,
1330 path: SharedString,
1331 color: Hsla,
1332 ) -> Result<()> {
1333 let scale_factor = self.scale_factor();
1334 let bounds = bounds.scale(scale_factor);
1335 // Render the SVG at twice the size to get a higher quality result.
1336 let params = RenderSvgParams {
1337 path,
1338 size: bounds
1339 .size
1340 .map(|pixels| DevicePixels::from((pixels.0 * 2.).ceil() as i32)),
1341 };
1342
1343 let tile =
1344 self.window
1345 .sprite_atlas
1346 .get_or_insert_with(¶ms.clone().into(), &mut || {
1347 let bytes = self.svg_renderer.render(¶ms)?;
1348 Ok((params.size, Cow::Owned(bytes)))
1349 })?;
1350 let content_mask = self.content_mask().scale(scale_factor);
1351 let view_id = self.parent_view_id();
1352
1353 let window = &mut *self.window;
1354 window.next_frame.scene.insert(
1355 &window.next_frame.z_index_stack,
1356 MonochromeSprite {
1357 view_id: view_id.into(),
1358 layer_id: 0,
1359 order: 0,
1360 bounds,
1361 content_mask,
1362 color,
1363 tile,
1364 },
1365 );
1366
1367 Ok(())
1368 }
1369
1370 /// Paint an image into the scene for the next frame at the current z-index.
1371 pub fn paint_image(
1372 &mut self,
1373 bounds: Bounds<Pixels>,
1374 corner_radii: Corners<Pixels>,
1375 data: Arc<ImageData>,
1376 grayscale: bool,
1377 ) -> Result<()> {
1378 let scale_factor = self.scale_factor();
1379 let bounds = bounds.scale(scale_factor);
1380 let params = RenderImageParams { image_id: data.id };
1381
1382 let tile = self
1383 .window
1384 .sprite_atlas
1385 .get_or_insert_with(¶ms.clone().into(), &mut || {
1386 Ok((data.size(), Cow::Borrowed(data.as_bytes())))
1387 })?;
1388 let content_mask = self.content_mask().scale(scale_factor);
1389 let corner_radii = corner_radii.scale(scale_factor);
1390 let view_id = self.parent_view_id();
1391
1392 let window = &mut *self.window;
1393 window.next_frame.scene.insert(
1394 &window.next_frame.z_index_stack,
1395 PolychromeSprite {
1396 view_id: view_id.into(),
1397 layer_id: 0,
1398 order: 0,
1399 bounds,
1400 content_mask,
1401 corner_radii,
1402 tile,
1403 grayscale,
1404 },
1405 );
1406 Ok(())
1407 }
1408
1409 /// Paint a surface into the scene for the next frame at the current z-index.
1410 pub fn paint_surface(&mut self, bounds: Bounds<Pixels>, image_buffer: CVImageBuffer) {
1411 let scale_factor = self.scale_factor();
1412 let bounds = bounds.scale(scale_factor);
1413 let content_mask = self.content_mask().scale(scale_factor);
1414 let view_id = self.parent_view_id();
1415 let window = &mut *self.window;
1416 window.next_frame.scene.insert(
1417 &window.next_frame.z_index_stack,
1418 Surface {
1419 view_id: view_id.into(),
1420 layer_id: 0,
1421 order: 0,
1422 bounds,
1423 content_mask,
1424 image_buffer,
1425 },
1426 );
1427 }
1428
1429 pub(crate) fn reuse_view(&mut self) {
1430 let view_id = self.parent_view_id();
1431 let grafted_view_ids = self
1432 .window
1433 .next_frame
1434 .dispatch_tree
1435 .graft(view_id, &mut self.window.rendered_frame.dispatch_tree);
1436 for view_id in grafted_view_ids {
1437 assert!(self.window.next_frame.reused_views.insert(view_id));
1438
1439 // Reuse the previous input handler if it was associated with one of
1440 // the views grafted from the tree in the previous frame.
1441 if self
1442 .window
1443 .rendered_frame
1444 .requested_input_handler
1445 .as_ref()
1446 .map_or(false, |requested| requested.view_id == view_id)
1447 {
1448 self.window.next_frame.requested_input_handler =
1449 self.window.rendered_frame.requested_input_handler.take();
1450 }
1451
1452 if let Some(style) = self.window.rendered_frame.cursor_styles.remove(&view_id) {
1453 self.window.next_frame.cursor_styles.insert(view_id, style);
1454 self.window.next_frame.requested_cursor_style = Some(style);
1455 }
1456 }
1457 }
1458
1459 /// Draw pixels to the display for this window based on the contents of its scene.
1460 pub(crate) fn draw(&mut self) {
1461 self.window.dirty = false;
1462 self.window.drawing = true;
1463
1464 #[cfg(any(test, feature = "test-support"))]
1465 {
1466 self.window.focus_invalidated = false;
1467 }
1468
1469 if let Some(requested_handler) = self.window.rendered_frame.requested_input_handler.as_mut()
1470 {
1471 requested_handler.handler = self.window.platform_window.take_input_handler();
1472 }
1473
1474 let root_view = self.window.root_view.take().unwrap();
1475
1476 self.with_z_index(0, |cx| {
1477 cx.with_key_dispatch(Some(KeyContext::default()), None, |_, cx| {
1478 for (action_type, action_listeners) in &cx.app.global_action_listeners {
1479 for action_listener in action_listeners.iter().cloned() {
1480 cx.window.next_frame.dispatch_tree.on_action(
1481 *action_type,
1482 Rc::new(move |action: &dyn Any, phase, cx: &mut WindowContext<'_>| {
1483 action_listener(action, phase, cx)
1484 }),
1485 )
1486 }
1487 }
1488
1489 let available_space = cx.window.viewport_size.map(Into::into);
1490 root_view.draw(Point::default(), available_space, cx);
1491 })
1492 });
1493
1494 if let Some(active_drag) = self.app.active_drag.take() {
1495 self.with_z_index(ACTIVE_DRAG_Z_INDEX, |cx| {
1496 let offset = cx.mouse_position() - active_drag.cursor_offset;
1497 let available_space = size(AvailableSpace::MinContent, AvailableSpace::MinContent);
1498 active_drag.view.draw(offset, available_space, cx);
1499 });
1500 self.active_drag = Some(active_drag);
1501 } else if let Some(active_tooltip) = self.app.active_tooltip.take() {
1502 self.with_z_index(1, |cx| {
1503 let available_space = size(AvailableSpace::MinContent, AvailableSpace::MinContent);
1504 active_tooltip
1505 .view
1506 .draw(active_tooltip.cursor_offset, available_space, cx);
1507 });
1508 }
1509 self.window.dirty_views.clear();
1510
1511 self.window
1512 .next_frame
1513 .dispatch_tree
1514 .preserve_pending_keystrokes(
1515 &mut self.window.rendered_frame.dispatch_tree,
1516 self.window.focus,
1517 );
1518 self.window.next_frame.focus = self.window.focus;
1519 self.window.next_frame.window_active = self.window.active;
1520 self.window.root_view = Some(root_view);
1521
1522 // Set the cursor only if we're the active window.
1523 let cursor_style = self
1524 .window
1525 .next_frame
1526 .requested_cursor_style
1527 .take()
1528 .unwrap_or(CursorStyle::Arrow);
1529 if self.is_window_active() {
1530 self.platform.set_cursor_style(cursor_style);
1531 }
1532
1533 // Register requested input handler with the platform window.
1534 if let Some(requested_input) = self.window.next_frame.requested_input_handler.as_mut() {
1535 if let Some(handler) = requested_input.handler.take() {
1536 self.window.platform_window.set_input_handler(handler);
1537 }
1538 }
1539
1540 self.window.layout_engine.as_mut().unwrap().clear();
1541 self.text_system()
1542 .finish_frame(&self.window.next_frame.reused_views);
1543 self.window
1544 .next_frame
1545 .finish(&mut self.window.rendered_frame);
1546 ELEMENT_ARENA.with_borrow_mut(|element_arena| element_arena.clear());
1547
1548 let previous_focus_path = self.window.rendered_frame.focus_path();
1549 let previous_window_active = self.window.rendered_frame.window_active;
1550 mem::swap(&mut self.window.rendered_frame, &mut self.window.next_frame);
1551 self.window.next_frame.clear();
1552 let current_focus_path = self.window.rendered_frame.focus_path();
1553 let current_window_active = self.window.rendered_frame.window_active;
1554
1555 if previous_focus_path != current_focus_path
1556 || previous_window_active != current_window_active
1557 {
1558 if !previous_focus_path.is_empty() && current_focus_path.is_empty() {
1559 self.window
1560 .focus_lost_listeners
1561 .clone()
1562 .retain(&(), |listener| listener(self));
1563 }
1564
1565 let event = FocusEvent {
1566 previous_focus_path: if previous_window_active {
1567 previous_focus_path
1568 } else {
1569 Default::default()
1570 },
1571 current_focus_path: if current_window_active {
1572 current_focus_path
1573 } else {
1574 Default::default()
1575 },
1576 };
1577 self.window
1578 .focus_listeners
1579 .clone()
1580 .retain(&(), |listener| listener(&event, self));
1581 }
1582
1583 self.window
1584 .platform_window
1585 .draw(&self.window.rendered_frame.scene);
1586 self.window.refreshing = false;
1587 self.window.drawing = false;
1588 }
1589
1590 /// Dispatch a mouse or keyboard event on the window.
1591 pub fn dispatch_event(&mut self, event: InputEvent) -> bool {
1592 // Handlers may set this to false by calling `stop_propagation`.
1593 self.app.propagate_event = true;
1594 // Handlers may set this to true by calling `prevent_default`.
1595 self.window.default_prevented = false;
1596
1597 let event = match event {
1598 // Track the mouse position with our own state, since accessing the platform
1599 // API for the mouse position can only occur on the main thread.
1600 InputEvent::MouseMove(mouse_move) => {
1601 self.window.mouse_position = mouse_move.position;
1602 self.window.modifiers = mouse_move.modifiers;
1603 InputEvent::MouseMove(mouse_move)
1604 }
1605 InputEvent::MouseDown(mouse_down) => {
1606 self.window.mouse_position = mouse_down.position;
1607 self.window.modifiers = mouse_down.modifiers;
1608 InputEvent::MouseDown(mouse_down)
1609 }
1610 InputEvent::MouseUp(mouse_up) => {
1611 self.window.mouse_position = mouse_up.position;
1612 self.window.modifiers = mouse_up.modifiers;
1613 InputEvent::MouseUp(mouse_up)
1614 }
1615 InputEvent::MouseExited(mouse_exited) => {
1616 self.window.modifiers = mouse_exited.modifiers;
1617 InputEvent::MouseExited(mouse_exited)
1618 }
1619 InputEvent::ModifiersChanged(modifiers_changed) => {
1620 self.window.modifiers = modifiers_changed.modifiers;
1621 InputEvent::ModifiersChanged(modifiers_changed)
1622 }
1623 InputEvent::ScrollWheel(scroll_wheel) => {
1624 self.window.mouse_position = scroll_wheel.position;
1625 self.window.modifiers = scroll_wheel.modifiers;
1626 InputEvent::ScrollWheel(scroll_wheel)
1627 }
1628 // Translate dragging and dropping of external files from the operating system
1629 // to internal drag and drop events.
1630 InputEvent::FileDrop(file_drop) => match file_drop {
1631 FileDropEvent::Entered { position, paths } => {
1632 self.window.mouse_position = position;
1633 if self.active_drag.is_none() {
1634 self.active_drag = Some(AnyDrag {
1635 value: Box::new(paths.clone()),
1636 view: self.new_view(|_| paths).into(),
1637 cursor_offset: position,
1638 });
1639 }
1640 InputEvent::MouseMove(MouseMoveEvent {
1641 position,
1642 pressed_button: Some(MouseButton::Left),
1643 modifiers: Modifiers::default(),
1644 })
1645 }
1646 FileDropEvent::Pending { position } => {
1647 self.window.mouse_position = position;
1648 InputEvent::MouseMove(MouseMoveEvent {
1649 position,
1650 pressed_button: Some(MouseButton::Left),
1651 modifiers: Modifiers::default(),
1652 })
1653 }
1654 FileDropEvent::Submit { position } => {
1655 self.activate(true);
1656 self.window.mouse_position = position;
1657 InputEvent::MouseUp(MouseUpEvent {
1658 button: MouseButton::Left,
1659 position,
1660 modifiers: Modifiers::default(),
1661 click_count: 1,
1662 })
1663 }
1664 FileDropEvent::Exited => InputEvent::MouseUp(MouseUpEvent {
1665 button: MouseButton::Left,
1666 position: Point::default(),
1667 modifiers: Modifiers::default(),
1668 click_count: 1,
1669 }),
1670 },
1671 InputEvent::KeyDown(_) | InputEvent::KeyUp(_) => event,
1672 };
1673
1674 if let Some(any_mouse_event) = event.mouse_event() {
1675 self.dispatch_mouse_event(any_mouse_event);
1676 } else if let Some(any_key_event) = event.keyboard_event() {
1677 self.dispatch_key_event(any_key_event);
1678 }
1679
1680 !self.app.propagate_event
1681 }
1682
1683 fn dispatch_mouse_event(&mut self, event: &dyn Any) {
1684 if let Some(mut handlers) = self
1685 .window
1686 .rendered_frame
1687 .mouse_listeners
1688 .remove(&event.type_id())
1689 {
1690 // Because handlers may add other handlers, we sort every time.
1691 handlers.sort_by(|(a, _, _), (b, _, _)| a.cmp(b));
1692
1693 // Capture phase, events bubble from back to front. Handlers for this phase are used for
1694 // special purposes, such as detecting events outside of a given Bounds.
1695 for (_, _, handler) in &mut handlers {
1696 handler(event, DispatchPhase::Capture, self);
1697 if !self.app.propagate_event {
1698 break;
1699 }
1700 }
1701
1702 // Bubble phase, where most normal handlers do their work.
1703 if self.app.propagate_event {
1704 for (_, _, handler) in handlers.iter_mut().rev() {
1705 handler(event, DispatchPhase::Bubble, self);
1706 if !self.app.propagate_event {
1707 break;
1708 }
1709 }
1710 }
1711
1712 self.window
1713 .rendered_frame
1714 .mouse_listeners
1715 .insert(event.type_id(), handlers);
1716 }
1717
1718 if self.app.propagate_event && self.has_active_drag() {
1719 if event.is::<MouseMoveEvent>() {
1720 // If this was a mouse move event, redraw the window so that the
1721 // active drag can follow the mouse cursor.
1722 self.refresh();
1723 } else if event.is::<MouseUpEvent>() {
1724 // If this was a mouse up event, cancel the active drag and redraw
1725 // the window.
1726 self.active_drag = None;
1727 self.refresh();
1728 }
1729 }
1730 }
1731
1732 fn dispatch_key_event(&mut self, event: &dyn Any) {
1733 let node_id = self
1734 .window
1735 .focus
1736 .and_then(|focus_id| {
1737 self.window
1738 .rendered_frame
1739 .dispatch_tree
1740 .focusable_node_id(focus_id)
1741 })
1742 .unwrap_or_else(|| self.window.rendered_frame.dispatch_tree.root_node_id());
1743
1744 let dispatch_path = self
1745 .window
1746 .rendered_frame
1747 .dispatch_tree
1748 .dispatch_path(node_id);
1749
1750 let mut actions: Vec<Box<dyn Action>> = Vec::new();
1751
1752 let mut context_stack: SmallVec<[KeyContext; 16]> = SmallVec::new();
1753 for node_id in &dispatch_path {
1754 let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1755
1756 if let Some(context) = node.context.clone() {
1757 context_stack.push(context);
1758 }
1759 }
1760
1761 for node_id in dispatch_path.iter().rev() {
1762 // Match keystrokes
1763 let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1764 if node.context.is_some() {
1765 if let Some(key_down_event) = event.downcast_ref::<KeyDownEvent>() {
1766 let mut new_actions = self
1767 .window
1768 .rendered_frame
1769 .dispatch_tree
1770 .dispatch_key(&key_down_event.keystroke, &context_stack);
1771 actions.append(&mut new_actions);
1772 }
1773
1774 context_stack.pop();
1775 }
1776 }
1777
1778 if !actions.is_empty() {
1779 self.clear_pending_keystrokes();
1780 }
1781
1782 self.propagate_event = true;
1783 for action in actions {
1784 self.dispatch_action_on_node(node_id, action.boxed_clone());
1785 if !self.propagate_event {
1786 self.dispatch_keystroke_observers(event, Some(action));
1787 return;
1788 }
1789 }
1790
1791 // Capture phase
1792 for node_id in &dispatch_path {
1793 let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1794
1795 for key_listener in node.key_listeners.clone() {
1796 key_listener(event, DispatchPhase::Capture, self);
1797 if !self.propagate_event {
1798 return;
1799 }
1800 }
1801 }
1802
1803 // Bubble phase
1804 for node_id in dispatch_path.iter().rev() {
1805 // Handle low level key events
1806 let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1807 for key_listener in node.key_listeners.clone() {
1808 key_listener(event, DispatchPhase::Bubble, self);
1809 if !self.propagate_event {
1810 return;
1811 }
1812 }
1813 }
1814
1815 self.dispatch_keystroke_observers(event, None);
1816 }
1817
1818 /// Determine whether a potential multi-stroke key binding is in progress on this window.
1819 pub fn has_pending_keystrokes(&self) -> bool {
1820 self.window
1821 .rendered_frame
1822 .dispatch_tree
1823 .has_pending_keystrokes()
1824 }
1825
1826 fn dispatch_action_on_node(&mut self, node_id: DispatchNodeId, action: Box<dyn Action>) {
1827 let dispatch_path = self
1828 .window
1829 .rendered_frame
1830 .dispatch_tree
1831 .dispatch_path(node_id);
1832
1833 // Capture phase
1834 for node_id in &dispatch_path {
1835 let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1836 for DispatchActionListener {
1837 action_type,
1838 listener,
1839 } in node.action_listeners.clone()
1840 {
1841 let any_action = action.as_any();
1842 if action_type == any_action.type_id() {
1843 listener(any_action, DispatchPhase::Capture, self);
1844 if !self.propagate_event {
1845 return;
1846 }
1847 }
1848 }
1849 }
1850 // Bubble phase
1851 for node_id in dispatch_path.iter().rev() {
1852 let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1853 for DispatchActionListener {
1854 action_type,
1855 listener,
1856 } in node.action_listeners.clone()
1857 {
1858 let any_action = action.as_any();
1859 if action_type == any_action.type_id() {
1860 self.propagate_event = false; // Actions stop propagation by default during the bubble phase
1861 listener(any_action, DispatchPhase::Bubble, self);
1862 if !self.propagate_event {
1863 return;
1864 }
1865 }
1866 }
1867 }
1868 }
1869
1870 /// Register the given handler to be invoked whenever the global of the given type
1871 /// is updated.
1872 pub fn observe_global<G: 'static>(
1873 &mut self,
1874 f: impl Fn(&mut WindowContext<'_>) + 'static,
1875 ) -> Subscription {
1876 let window_handle = self.window.handle;
1877 let (subscription, activate) = self.global_observers.insert(
1878 TypeId::of::<G>(),
1879 Box::new(move |cx| window_handle.update(cx, |_, cx| f(cx)).is_ok()),
1880 );
1881 self.app.defer(move |_| activate());
1882 subscription
1883 }
1884
1885 /// Focus the current window and bring it to the foreground at the platform level.
1886 pub fn activate_window(&self) {
1887 self.window.platform_window.activate();
1888 }
1889
1890 /// Minimize the current window at the platform level.
1891 pub fn minimize_window(&self) {
1892 self.window.platform_window.minimize();
1893 }
1894
1895 /// Toggle full screen status on the current window at the platform level.
1896 pub fn toggle_full_screen(&self) {
1897 self.window.platform_window.toggle_full_screen();
1898 }
1899
1900 /// Present a platform dialog.
1901 /// The provided message will be presented, along with buttons for each answer.
1902 /// When a button is clicked, the returned Receiver will receive the index of the clicked button.
1903 pub fn prompt(
1904 &self,
1905 level: PromptLevel,
1906 message: &str,
1907 answers: &[&str],
1908 ) -> oneshot::Receiver<usize> {
1909 self.window.platform_window.prompt(level, message, answers)
1910 }
1911
1912 /// Returns all available actions for the focused element.
1913 pub fn available_actions(&self) -> Vec<Box<dyn Action>> {
1914 let node_id = self
1915 .window
1916 .focus
1917 .and_then(|focus_id| {
1918 self.window
1919 .rendered_frame
1920 .dispatch_tree
1921 .focusable_node_id(focus_id)
1922 })
1923 .unwrap_or_else(|| self.window.rendered_frame.dispatch_tree.root_node_id());
1924
1925 self.window
1926 .rendered_frame
1927 .dispatch_tree
1928 .available_actions(node_id)
1929 }
1930
1931 /// Returns key bindings that invoke the given action on the currently focused element.
1932 pub fn bindings_for_action(&self, action: &dyn Action) -> Vec<KeyBinding> {
1933 self.window
1934 .rendered_frame
1935 .dispatch_tree
1936 .bindings_for_action(
1937 action,
1938 &self.window.rendered_frame.dispatch_tree.context_stack,
1939 )
1940 }
1941
1942 /// Returns any bindings that would invoke the given action on the given focus handle if it were focused.
1943 pub fn bindings_for_action_in(
1944 &self,
1945 action: &dyn Action,
1946 focus_handle: &FocusHandle,
1947 ) -> Vec<KeyBinding> {
1948 let dispatch_tree = &self.window.rendered_frame.dispatch_tree;
1949
1950 let Some(node_id) = dispatch_tree.focusable_node_id(focus_handle.id) else {
1951 return vec![];
1952 };
1953 let context_stack = dispatch_tree
1954 .dispatch_path(node_id)
1955 .into_iter()
1956 .filter_map(|node_id| dispatch_tree.node(node_id).context.clone())
1957 .collect();
1958 dispatch_tree.bindings_for_action(action, &context_stack)
1959 }
1960
1961 /// Returns a generic event listener that invokes the given listener with the view and context associated with the given view handle.
1962 pub fn listener_for<V: Render, E>(
1963 &self,
1964 view: &View<V>,
1965 f: impl Fn(&mut V, &E, &mut ViewContext<V>) + 'static,
1966 ) -> impl Fn(&E, &mut WindowContext) + 'static {
1967 let view = view.downgrade();
1968 move |e: &E, cx: &mut WindowContext| {
1969 view.update(cx, |view, cx| f(view, e, cx)).ok();
1970 }
1971 }
1972
1973 /// Returns a generic handler that invokes the given handler with the view and context associated with the given view handle.
1974 pub fn handler_for<V: Render>(
1975 &self,
1976 view: &View<V>,
1977 f: impl Fn(&mut V, &mut ViewContext<V>) + 'static,
1978 ) -> impl Fn(&mut WindowContext) {
1979 let view = view.downgrade();
1980 move |cx: &mut WindowContext| {
1981 view.update(cx, |view, cx| f(view, cx)).ok();
1982 }
1983 }
1984
1985 /// Invoke the given function with the given focus handle present on the key dispatch stack.
1986 /// If you want an element to participate in key dispatch, use this method to push its key context and focus handle into the stack during paint.
1987 pub fn with_key_dispatch<R>(
1988 &mut self,
1989 context: Option<KeyContext>,
1990 focus_handle: Option<FocusHandle>,
1991 f: impl FnOnce(Option<FocusHandle>, &mut Self) -> R,
1992 ) -> R {
1993 let window = &mut self.window;
1994 let focus_id = focus_handle.as_ref().map(|handle| handle.id);
1995 window
1996 .next_frame
1997 .dispatch_tree
1998 .push_node(context.clone(), focus_id, None);
1999
2000 let result = f(focus_handle, self);
2001
2002 self.window.next_frame.dispatch_tree.pop_node();
2003
2004 result
2005 }
2006
2007 /// Invoke the given function with the given view id present on the view stack.
2008 /// This is a fairly low-level method used to layout views.
2009 pub fn with_view_id<R>(&mut self, view_id: EntityId, f: impl FnOnce(&mut Self) -> R) -> R {
2010 let text_system = self.text_system().clone();
2011 text_system.with_view(view_id, || {
2012 if self.window.next_frame.view_stack.last() == Some(&view_id) {
2013 return f(self);
2014 } else {
2015 self.window.next_frame.view_stack.push(view_id);
2016 let result = f(self);
2017 self.window.next_frame.view_stack.pop();
2018 result
2019 }
2020 })
2021 }
2022
2023 /// Invoke the given function with the given view id present on the view stack.
2024 /// This is a fairly low-level method used to paint views.
2025 pub fn paint_view<R>(&mut self, view_id: EntityId, f: impl FnOnce(&mut Self) -> R) -> R {
2026 let text_system = self.text_system().clone();
2027 text_system.with_view(view_id, || {
2028 if self.window.next_frame.view_stack.last() == Some(&view_id) {
2029 return f(self);
2030 } else {
2031 self.window.next_frame.view_stack.push(view_id);
2032 self.window
2033 .next_frame
2034 .dispatch_tree
2035 .push_node(None, None, Some(view_id));
2036 let result = f(self);
2037 self.window.next_frame.dispatch_tree.pop_node();
2038 self.window.next_frame.view_stack.pop();
2039 result
2040 }
2041 })
2042 }
2043
2044 /// Update or initialize state for an element with the given id that lives across multiple
2045 /// frames. If an element with this id existed in the rendered frame, its state will be passed
2046 /// to the given closure. The state returned by the closure will be stored so it can be referenced
2047 /// when drawing the next frame.
2048 pub(crate) fn with_element_state<S, R>(
2049 &mut self,
2050 id: ElementId,
2051 f: impl FnOnce(Option<S>, &mut Self) -> (R, S),
2052 ) -> R
2053 where
2054 S: 'static,
2055 {
2056 self.with_element_id(Some(id), |cx| {
2057 let global_id = cx.window().element_id_stack.clone();
2058
2059 if let Some(any) = cx
2060 .window_mut()
2061 .next_frame
2062 .element_states
2063 .remove(&global_id)
2064 .or_else(|| {
2065 cx.window_mut()
2066 .rendered_frame
2067 .element_states
2068 .remove(&global_id)
2069 })
2070 {
2071 let ElementStateBox {
2072 inner,
2073 parent_view_id,
2074 #[cfg(debug_assertions)]
2075 type_name
2076 } = any;
2077 // Using the extra inner option to avoid needing to reallocate a new box.
2078 let mut state_box = inner
2079 .downcast::<Option<S>>()
2080 .map_err(|_| {
2081 #[cfg(debug_assertions)]
2082 {
2083 anyhow!(
2084 "invalid element state type for id, requested_type {:?}, actual type: {:?}",
2085 std::any::type_name::<S>(),
2086 type_name
2087 )
2088 }
2089
2090 #[cfg(not(debug_assertions))]
2091 {
2092 anyhow!(
2093 "invalid element state type for id, requested_type {:?}",
2094 std::any::type_name::<S>(),
2095 )
2096 }
2097 })
2098 .unwrap();
2099
2100 // Actual: Option<AnyElement> <- View
2101 // Requested: () <- AnyElemet
2102 let state = state_box
2103 .take()
2104 .expect("element state is already on the stack");
2105 let (result, state) = f(Some(state), cx);
2106 state_box.replace(state);
2107 cx.window_mut()
2108 .next_frame
2109 .element_states
2110 .insert(global_id, ElementStateBox {
2111 inner: state_box,
2112 parent_view_id,
2113 #[cfg(debug_assertions)]
2114 type_name
2115 });
2116 result
2117 } else {
2118 let (result, state) = f(None, cx);
2119 let parent_view_id = cx.parent_view_id();
2120 cx.window_mut()
2121 .next_frame
2122 .element_states
2123 .insert(global_id,
2124 ElementStateBox {
2125 inner: Box::new(Some(state)),
2126 parent_view_id,
2127 #[cfg(debug_assertions)]
2128 type_name: std::any::type_name::<S>()
2129 }
2130
2131 );
2132 result
2133 }
2134 })
2135 }
2136
2137 fn parent_view_id(&self) -> EntityId {
2138 *self
2139 .window
2140 .next_frame
2141 .view_stack
2142 .last()
2143 .expect("a view should always be on the stack while drawing")
2144 }
2145
2146 /// Set an input handler, such as [`ElementInputHandler`][element_input_handler], which interfaces with the
2147 /// platform to receive textual input with proper integration with concerns such
2148 /// as IME interactions.
2149 ///
2150 /// [element_input_handler]: crate::ElementInputHandler
2151 pub fn handle_input(
2152 &mut self,
2153 focus_handle: &FocusHandle,
2154 input_handler: impl PlatformInputHandler,
2155 ) {
2156 if focus_handle.is_focused(self) {
2157 let view_id = self.parent_view_id();
2158 self.window.next_frame.requested_input_handler = Some(RequestedInputHandler {
2159 view_id,
2160 handler: Some(Box::new(input_handler)),
2161 })
2162 }
2163 }
2164
2165 /// Register a callback that can interrupt the closing of the current window based the returned boolean.
2166 /// If the callback returns false, the window won't be closed.
2167 pub fn on_window_should_close(&mut self, f: impl Fn(&mut WindowContext) -> bool + 'static) {
2168 let mut this = self.to_async();
2169 self.window
2170 .platform_window
2171 .on_should_close(Box::new(move || {
2172 this.update(|_, cx| {
2173 // Ensure that the window is removed from the app if it's been closed
2174 // by always pre-empting the system close event.
2175 if f(cx) {
2176 cx.remove_window();
2177 }
2178 false
2179 })
2180 .unwrap_or(true)
2181 }))
2182 }
2183}
2184
2185impl Context for WindowContext<'_> {
2186 type Result<T> = T;
2187
2188 fn new_model<T>(&mut self, build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T) -> Model<T>
2189 where
2190 T: 'static,
2191 {
2192 let slot = self.app.entities.reserve();
2193 let model = build_model(&mut ModelContext::new(&mut *self.app, slot.downgrade()));
2194 self.entities.insert(slot, model)
2195 }
2196
2197 fn update_model<T: 'static, R>(
2198 &mut self,
2199 model: &Model<T>,
2200 update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
2201 ) -> R {
2202 let mut entity = self.entities.lease(model);
2203 let result = update(
2204 &mut *entity,
2205 &mut ModelContext::new(&mut *self.app, model.downgrade()),
2206 );
2207 self.entities.end_lease(entity);
2208 result
2209 }
2210
2211 fn update_window<T, F>(&mut self, window: AnyWindowHandle, update: F) -> Result<T>
2212 where
2213 F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
2214 {
2215 if window == self.window.handle {
2216 let root_view = self.window.root_view.clone().unwrap();
2217 Ok(update(root_view, self))
2218 } else {
2219 window.update(self.app, update)
2220 }
2221 }
2222
2223 fn read_model<T, R>(
2224 &self,
2225 handle: &Model<T>,
2226 read: impl FnOnce(&T, &AppContext) -> R,
2227 ) -> Self::Result<R>
2228 where
2229 T: 'static,
2230 {
2231 let entity = self.entities.read(handle);
2232 read(entity, &*self.app)
2233 }
2234
2235 fn read_window<T, R>(
2236 &self,
2237 window: &WindowHandle<T>,
2238 read: impl FnOnce(View<T>, &AppContext) -> R,
2239 ) -> Result<R>
2240 where
2241 T: 'static,
2242 {
2243 if window.any_handle == self.window.handle {
2244 let root_view = self
2245 .window
2246 .root_view
2247 .clone()
2248 .unwrap()
2249 .downcast::<T>()
2250 .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
2251 Ok(read(root_view, self))
2252 } else {
2253 self.app.read_window(window, read)
2254 }
2255 }
2256}
2257
2258impl VisualContext for WindowContext<'_> {
2259 fn new_view<V>(
2260 &mut self,
2261 build_view_state: impl FnOnce(&mut ViewContext<'_, V>) -> V,
2262 ) -> Self::Result<View<V>>
2263 where
2264 V: 'static + Render,
2265 {
2266 let slot = self.app.entities.reserve();
2267 let view = View {
2268 model: slot.clone(),
2269 };
2270 let mut cx = ViewContext::new(&mut *self.app, &mut *self.window, &view);
2271 let entity = build_view_state(&mut cx);
2272 cx.entities.insert(slot, entity);
2273
2274 cx.new_view_observers
2275 .clone()
2276 .retain(&TypeId::of::<V>(), |observer| {
2277 let any_view = AnyView::from(view.clone());
2278 (observer)(any_view, self);
2279 true
2280 });
2281
2282 view
2283 }
2284
2285 /// Update the given view. Prefer calling `View::update` instead, which calls this method.
2286 fn update_view<T: 'static, R>(
2287 &mut self,
2288 view: &View<T>,
2289 update: impl FnOnce(&mut T, &mut ViewContext<'_, T>) -> R,
2290 ) -> Self::Result<R> {
2291 let mut lease = self.app.entities.lease(&view.model);
2292 let mut cx = ViewContext::new(&mut *self.app, &mut *self.window, view);
2293 let result = update(&mut *lease, &mut cx);
2294 cx.app.entities.end_lease(lease);
2295 result
2296 }
2297
2298 fn replace_root_view<V>(
2299 &mut self,
2300 build_view: impl FnOnce(&mut ViewContext<'_, V>) -> V,
2301 ) -> Self::Result<View<V>>
2302 where
2303 V: 'static + Render,
2304 {
2305 let view = self.new_view(build_view);
2306 self.window.root_view = Some(view.clone().into());
2307 self.refresh();
2308 view
2309 }
2310
2311 fn focus_view<V: crate::FocusableView>(&mut self, view: &View<V>) -> Self::Result<()> {
2312 self.update_view(view, |view, cx| {
2313 view.focus_handle(cx).clone().focus(cx);
2314 })
2315 }
2316
2317 fn dismiss_view<V>(&mut self, view: &View<V>) -> Self::Result<()>
2318 where
2319 V: ManagedView,
2320 {
2321 self.update_view(view, |_, cx| cx.emit(DismissEvent))
2322 }
2323}
2324
2325impl<'a> std::ops::Deref for WindowContext<'a> {
2326 type Target = AppContext;
2327
2328 fn deref(&self) -> &Self::Target {
2329 self.app
2330 }
2331}
2332
2333impl<'a> std::ops::DerefMut for WindowContext<'a> {
2334 fn deref_mut(&mut self) -> &mut Self::Target {
2335 self.app
2336 }
2337}
2338
2339impl<'a> Borrow<AppContext> for WindowContext<'a> {
2340 fn borrow(&self) -> &AppContext {
2341 self.app
2342 }
2343}
2344
2345impl<'a> BorrowMut<AppContext> for WindowContext<'a> {
2346 fn borrow_mut(&mut self) -> &mut AppContext {
2347 self.app
2348 }
2349}
2350
2351/// This trait contains functionality that is shared across [`ViewContext`] and [`WindowContext`]
2352pub trait BorrowWindow: BorrowMut<Window> + BorrowMut<AppContext> {
2353 #[doc(hidden)]
2354 fn app_mut(&mut self) -> &mut AppContext {
2355 self.borrow_mut()
2356 }
2357
2358 #[doc(hidden)]
2359 fn app(&self) -> &AppContext {
2360 self.borrow()
2361 }
2362
2363 #[doc(hidden)]
2364 fn window(&self) -> &Window {
2365 self.borrow()
2366 }
2367
2368 #[doc(hidden)]
2369 fn window_mut(&mut self) -> &mut Window {
2370 self.borrow_mut()
2371 }
2372
2373 /// Pushes the given element id onto the global stack and invokes the given closure
2374 /// with a `GlobalElementId`, which disambiguates the given id in the context of its ancestor
2375 /// ids. Because elements are discarded and recreated on each frame, the `GlobalElementId` is
2376 /// used to associate state with identified elements across separate frames.
2377 fn with_element_id<R>(
2378 &mut self,
2379 id: Option<impl Into<ElementId>>,
2380 f: impl FnOnce(&mut Self) -> R,
2381 ) -> R {
2382 if let Some(id) = id.map(Into::into) {
2383 let window = self.window_mut();
2384 window.element_id_stack.push(id);
2385 let result = f(self);
2386 let window: &mut Window = self.borrow_mut();
2387 window.element_id_stack.pop();
2388 result
2389 } else {
2390 f(self)
2391 }
2392 }
2393
2394 /// Invoke the given function with the given content mask after intersecting it
2395 /// with the current mask.
2396 fn with_content_mask<R>(
2397 &mut self,
2398 mask: Option<ContentMask<Pixels>>,
2399 f: impl FnOnce(&mut Self) -> R,
2400 ) -> R {
2401 if let Some(mask) = mask {
2402 let mask = mask.intersect(&self.content_mask());
2403 self.window_mut().next_frame.content_mask_stack.push(mask);
2404 let result = f(self);
2405 self.window_mut().next_frame.content_mask_stack.pop();
2406 result
2407 } else {
2408 f(self)
2409 }
2410 }
2411
2412 /// Invoke the given function with the content mask reset to that
2413 /// of the window.
2414 fn break_content_mask<R>(&mut self, f: impl FnOnce(&mut Self) -> R) -> R {
2415 let mask = ContentMask {
2416 bounds: Bounds {
2417 origin: Point::default(),
2418 size: self.window().viewport_size,
2419 },
2420 };
2421 let new_stacking_order_id =
2422 post_inc(&mut self.window_mut().next_frame.next_stacking_order_id);
2423 let old_stacking_order = mem::take(&mut self.window_mut().next_frame.z_index_stack);
2424 self.window_mut().next_frame.z_index_stack.id = new_stacking_order_id;
2425 self.window_mut().next_frame.content_mask_stack.push(mask);
2426 let result = f(self);
2427 self.window_mut().next_frame.content_mask_stack.pop();
2428 self.window_mut().next_frame.z_index_stack = old_stacking_order;
2429 result
2430 }
2431
2432 /// Called during painting to invoke the given closure in a new stacking context. The given
2433 /// z-index is interpreted relative to the previous call to `stack`.
2434 fn with_z_index<R>(&mut self, z_index: u8, f: impl FnOnce(&mut Self) -> R) -> R {
2435 let new_stacking_order_id =
2436 post_inc(&mut self.window_mut().next_frame.next_stacking_order_id);
2437 let old_stacking_order_id = mem::replace(
2438 &mut self.window_mut().next_frame.z_index_stack.id,
2439 new_stacking_order_id,
2440 );
2441 self.window_mut().next_frame.z_index_stack.id = new_stacking_order_id;
2442 self.window_mut().next_frame.z_index_stack.push(z_index);
2443 let result = f(self);
2444 self.window_mut().next_frame.z_index_stack.id = old_stacking_order_id;
2445 self.window_mut().next_frame.z_index_stack.pop();
2446 result
2447 }
2448
2449 /// Update the global element offset relative to the current offset. This is used to implement
2450 /// scrolling.
2451 fn with_element_offset<R>(
2452 &mut self,
2453 offset: Point<Pixels>,
2454 f: impl FnOnce(&mut Self) -> R,
2455 ) -> R {
2456 if offset.is_zero() {
2457 return f(self);
2458 };
2459
2460 let abs_offset = self.element_offset() + offset;
2461 self.with_absolute_element_offset(abs_offset, f)
2462 }
2463
2464 /// Update the global element offset based on the given offset. This is used to implement
2465 /// drag handles and other manual painting of elements.
2466 fn with_absolute_element_offset<R>(
2467 &mut self,
2468 offset: Point<Pixels>,
2469 f: impl FnOnce(&mut Self) -> R,
2470 ) -> R {
2471 self.window_mut()
2472 .next_frame
2473 .element_offset_stack
2474 .push(offset);
2475 let result = f(self);
2476 self.window_mut().next_frame.element_offset_stack.pop();
2477 result
2478 }
2479
2480 /// Obtain the current element offset.
2481 fn element_offset(&self) -> Point<Pixels> {
2482 self.window()
2483 .next_frame
2484 .element_offset_stack
2485 .last()
2486 .copied()
2487 .unwrap_or_default()
2488 }
2489
2490 /// Obtain the current content mask.
2491 fn content_mask(&self) -> ContentMask<Pixels> {
2492 self.window()
2493 .next_frame
2494 .content_mask_stack
2495 .last()
2496 .cloned()
2497 .unwrap_or_else(|| ContentMask {
2498 bounds: Bounds {
2499 origin: Point::default(),
2500 size: self.window().viewport_size,
2501 },
2502 })
2503 }
2504
2505 /// The size of an em for the base font of the application. Adjusting this value allows the
2506 /// UI to scale, just like zooming a web page.
2507 fn rem_size(&self) -> Pixels {
2508 self.window().rem_size
2509 }
2510}
2511
2512impl Borrow<Window> for WindowContext<'_> {
2513 fn borrow(&self) -> &Window {
2514 self.window
2515 }
2516}
2517
2518impl BorrowMut<Window> for WindowContext<'_> {
2519 fn borrow_mut(&mut self) -> &mut Window {
2520 self.window
2521 }
2522}
2523
2524impl<T> BorrowWindow for T where T: BorrowMut<AppContext> + BorrowMut<Window> {}
2525
2526/// Provides access to application state that is specialized for a particular [`View`].
2527/// Allows you to interact with focus, emit events, etc.
2528/// ViewContext also derefs to [`WindowContext`], giving you access to all of its methods as well.
2529/// When you call [`View::update`], you're passed a `&mut V` and an `&mut ViewContext<V>`.
2530pub struct ViewContext<'a, V> {
2531 window_cx: WindowContext<'a>,
2532 view: &'a View<V>,
2533}
2534
2535impl<V> Borrow<AppContext> for ViewContext<'_, V> {
2536 fn borrow(&self) -> &AppContext {
2537 &*self.window_cx.app
2538 }
2539}
2540
2541impl<V> BorrowMut<AppContext> for ViewContext<'_, V> {
2542 fn borrow_mut(&mut self) -> &mut AppContext {
2543 &mut *self.window_cx.app
2544 }
2545}
2546
2547impl<V> Borrow<Window> for ViewContext<'_, V> {
2548 fn borrow(&self) -> &Window {
2549 &*self.window_cx.window
2550 }
2551}
2552
2553impl<V> BorrowMut<Window> for ViewContext<'_, V> {
2554 fn borrow_mut(&mut self) -> &mut Window {
2555 &mut *self.window_cx.window
2556 }
2557}
2558
2559impl<'a, V: 'static> ViewContext<'a, V> {
2560 pub(crate) fn new(app: &'a mut AppContext, window: &'a mut Window, view: &'a View<V>) -> Self {
2561 Self {
2562 window_cx: WindowContext::new(app, window),
2563 view,
2564 }
2565 }
2566
2567 /// Get the entity_id of this view.
2568 pub fn entity_id(&self) -> EntityId {
2569 self.view.entity_id()
2570 }
2571
2572 /// Get the view pointer underlying this context.
2573 pub fn view(&self) -> &View<V> {
2574 self.view
2575 }
2576
2577 /// Get the model underlying this view.
2578 pub fn model(&self) -> &Model<V> {
2579 &self.view.model
2580 }
2581
2582 /// Access the underlying window context.
2583 pub fn window_context(&mut self) -> &mut WindowContext<'a> {
2584 &mut self.window_cx
2585 }
2586
2587 /// Set a given callback to be run on the next frame.
2588 pub fn on_next_frame(&mut self, f: impl FnOnce(&mut V, &mut ViewContext<V>) + 'static)
2589 where
2590 V: 'static,
2591 {
2592 let view = self.view().clone();
2593 self.window_cx.on_next_frame(move |cx| view.update(cx, f));
2594 }
2595
2596 /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
2597 /// that are currently on the stack to be returned to the app.
2598 pub fn defer(&mut self, f: impl FnOnce(&mut V, &mut ViewContext<V>) + 'static) {
2599 let view = self.view().downgrade();
2600 self.window_cx.defer(move |cx| {
2601 view.update(cx, f).ok();
2602 });
2603 }
2604
2605 /// Observe another model or view for changes to its state, as tracked by [`ModelContext::notify`].
2606 pub fn observe<V2, E>(
2607 &mut self,
2608 entity: &E,
2609 mut on_notify: impl FnMut(&mut V, E, &mut ViewContext<'_, V>) + 'static,
2610 ) -> Subscription
2611 where
2612 V2: 'static,
2613 V: 'static,
2614 E: Entity<V2>,
2615 {
2616 let view = self.view().downgrade();
2617 let entity_id = entity.entity_id();
2618 let entity = entity.downgrade();
2619 let window_handle = self.window.handle;
2620 let (subscription, activate) = self.app.observers.insert(
2621 entity_id,
2622 Box::new(move |cx| {
2623 window_handle
2624 .update(cx, |_, cx| {
2625 if let Some(handle) = E::upgrade_from(&entity) {
2626 view.update(cx, |this, cx| on_notify(this, handle, cx))
2627 .is_ok()
2628 } else {
2629 false
2630 }
2631 })
2632 .unwrap_or(false)
2633 }),
2634 );
2635 self.app.defer(move |_| activate());
2636 subscription
2637 }
2638
2639 /// Subscribe to events emitted by another model or view.
2640 /// The entity to which you're subscribing must implement the [`EventEmitter`] trait.
2641 /// 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.
2642 pub fn subscribe<V2, E, Evt>(
2643 &mut self,
2644 entity: &E,
2645 mut on_event: impl FnMut(&mut V, E, &Evt, &mut ViewContext<'_, V>) + 'static,
2646 ) -> Subscription
2647 where
2648 V2: EventEmitter<Evt>,
2649 E: Entity<V2>,
2650 Evt: 'static,
2651 {
2652 let view = self.view().downgrade();
2653 let entity_id = entity.entity_id();
2654 let handle = entity.downgrade();
2655 let window_handle = self.window.handle;
2656 let (subscription, activate) = self.app.event_listeners.insert(
2657 entity_id,
2658 (
2659 TypeId::of::<Evt>(),
2660 Box::new(move |event, cx| {
2661 window_handle
2662 .update(cx, |_, cx| {
2663 if let Some(handle) = E::upgrade_from(&handle) {
2664 let event = event.downcast_ref().expect("invalid event type");
2665 view.update(cx, |this, cx| on_event(this, handle, event, cx))
2666 .is_ok()
2667 } else {
2668 false
2669 }
2670 })
2671 .unwrap_or(false)
2672 }),
2673 ),
2674 );
2675 self.app.defer(move |_| activate());
2676 subscription
2677 }
2678
2679 /// Register a callback to be invoked when the view is released.
2680 ///
2681 /// The callback receives a handle to the view's window. This handle may be
2682 /// invalid, if the window was closed before the view was released.
2683 pub fn on_release(
2684 &mut self,
2685 on_release: impl FnOnce(&mut V, AnyWindowHandle, &mut AppContext) + 'static,
2686 ) -> Subscription {
2687 let window_handle = self.window.handle;
2688 let (subscription, activate) = self.app.release_listeners.insert(
2689 self.view.model.entity_id,
2690 Box::new(move |this, cx| {
2691 let this = this.downcast_mut().expect("invalid entity type");
2692 on_release(this, window_handle, cx)
2693 }),
2694 );
2695 activate();
2696 subscription
2697 }
2698
2699 /// Register a callback to be invoked when the given Model or View is released.
2700 pub fn observe_release<V2, E>(
2701 &mut self,
2702 entity: &E,
2703 mut on_release: impl FnMut(&mut V, &mut V2, &mut ViewContext<'_, V>) + 'static,
2704 ) -> Subscription
2705 where
2706 V: 'static,
2707 V2: 'static,
2708 E: Entity<V2>,
2709 {
2710 let view = self.view().downgrade();
2711 let entity_id = entity.entity_id();
2712 let window_handle = self.window.handle;
2713 let (subscription, activate) = self.app.release_listeners.insert(
2714 entity_id,
2715 Box::new(move |entity, cx| {
2716 let entity = entity.downcast_mut().expect("invalid entity type");
2717 let _ = window_handle.update(cx, |_, cx| {
2718 view.update(cx, |this, cx| on_release(this, entity, cx))
2719 });
2720 }),
2721 );
2722 activate();
2723 subscription
2724 }
2725
2726 /// Indicate that this view has changed, which will invoke any observers and also mark the window as dirty.
2727 /// If this view or any of its ancestors are *cached*, notifying it will cause it or its ancestors to be redrawn.
2728 pub fn notify(&mut self) {
2729 for view_id in self
2730 .window
2731 .rendered_frame
2732 .dispatch_tree
2733 .view_path(self.view.entity_id())
2734 {
2735 if !self.window.dirty_views.insert(view_id) {
2736 break;
2737 }
2738 }
2739
2740 if !self.window.drawing {
2741 self.window_cx.window.dirty = true;
2742 self.window_cx.app.push_effect(Effect::Notify {
2743 emitter: self.view.model.entity_id,
2744 });
2745 }
2746 }
2747
2748 /// Register a callback to be invoked when the window is resized.
2749 pub fn observe_window_bounds(
2750 &mut self,
2751 mut callback: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2752 ) -> Subscription {
2753 let view = self.view.downgrade();
2754 let (subscription, activate) = self.window.bounds_observers.insert(
2755 (),
2756 Box::new(move |cx| view.update(cx, |view, cx| callback(view, cx)).is_ok()),
2757 );
2758 activate();
2759 subscription
2760 }
2761
2762 /// Register a callback to be invoked when the window is activated or deactivated.
2763 pub fn observe_window_activation(
2764 &mut self,
2765 mut callback: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2766 ) -> Subscription {
2767 let view = self.view.downgrade();
2768 let (subscription, activate) = self.window.activation_observers.insert(
2769 (),
2770 Box::new(move |cx| view.update(cx, |view, cx| callback(view, cx)).is_ok()),
2771 );
2772 activate();
2773 subscription
2774 }
2775
2776 /// Register a listener to be called when the given focus handle receives focus.
2777 /// Returns a subscription and persists until the subscription is dropped.
2778 pub fn on_focus(
2779 &mut self,
2780 handle: &FocusHandle,
2781 mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2782 ) -> Subscription {
2783 let view = self.view.downgrade();
2784 let focus_id = handle.id;
2785 let (subscription, activate) = self.window.focus_listeners.insert(
2786 (),
2787 Box::new(move |event, cx| {
2788 view.update(cx, |view, cx| {
2789 if event.previous_focus_path.last() != Some(&focus_id)
2790 && event.current_focus_path.last() == Some(&focus_id)
2791 {
2792 listener(view, cx)
2793 }
2794 })
2795 .is_ok()
2796 }),
2797 );
2798 self.app.defer(move |_| activate());
2799 subscription
2800 }
2801
2802 /// Register a listener to be called when the given focus handle or one of its descendants receives focus.
2803 /// Returns a subscription and persists until the subscription is dropped.
2804 pub fn on_focus_in(
2805 &mut self,
2806 handle: &FocusHandle,
2807 mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2808 ) -> Subscription {
2809 let view = self.view.downgrade();
2810 let focus_id = handle.id;
2811 let (subscription, activate) = self.window.focus_listeners.insert(
2812 (),
2813 Box::new(move |event, cx| {
2814 view.update(cx, |view, cx| {
2815 if !event.previous_focus_path.contains(&focus_id)
2816 && event.current_focus_path.contains(&focus_id)
2817 {
2818 listener(view, cx)
2819 }
2820 })
2821 .is_ok()
2822 }),
2823 );
2824 self.app.defer(move |_| activate());
2825 subscription
2826 }
2827
2828 /// Register a listener to be called when the given focus handle loses focus.
2829 /// Returns a subscription and persists until the subscription is dropped.
2830 pub fn on_blur(
2831 &mut self,
2832 handle: &FocusHandle,
2833 mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2834 ) -> Subscription {
2835 let view = self.view.downgrade();
2836 let focus_id = handle.id;
2837 let (subscription, activate) = self.window.focus_listeners.insert(
2838 (),
2839 Box::new(move |event, cx| {
2840 view.update(cx, |view, cx| {
2841 if event.previous_focus_path.last() == Some(&focus_id)
2842 && event.current_focus_path.last() != Some(&focus_id)
2843 {
2844 listener(view, cx)
2845 }
2846 })
2847 .is_ok()
2848 }),
2849 );
2850 self.app.defer(move |_| activate());
2851 subscription
2852 }
2853
2854 /// Register a listener to be called when nothing in the window has focus.
2855 /// This typically happens when the node that was focused is removed from the tree,
2856 /// and this callback lets you chose a default place to restore the users focus.
2857 /// Returns a subscription and persists until the subscription is dropped.
2858 pub fn on_focus_lost(
2859 &mut self,
2860 mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2861 ) -> Subscription {
2862 let view = self.view.downgrade();
2863 let (subscription, activate) = self.window.focus_lost_listeners.insert(
2864 (),
2865 Box::new(move |cx| view.update(cx, |view, cx| listener(view, cx)).is_ok()),
2866 );
2867 activate();
2868 subscription
2869 }
2870
2871 /// Register a listener to be called when the given focus handle or one of its descendants loses focus.
2872 /// Returns a subscription and persists until the subscription is dropped.
2873 pub fn on_focus_out(
2874 &mut self,
2875 handle: &FocusHandle,
2876 mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2877 ) -> Subscription {
2878 let view = self.view.downgrade();
2879 let focus_id = handle.id;
2880 let (subscription, activate) = self.window.focus_listeners.insert(
2881 (),
2882 Box::new(move |event, cx| {
2883 view.update(cx, |view, cx| {
2884 if event.previous_focus_path.contains(&focus_id)
2885 && !event.current_focus_path.contains(&focus_id)
2886 {
2887 listener(view, cx)
2888 }
2889 })
2890 .is_ok()
2891 }),
2892 );
2893 self.app.defer(move |_| activate());
2894 subscription
2895 }
2896
2897 /// Schedule a future to be run asynchronously.
2898 /// The given callback is invoked with a [`WeakView<V>`] to avoid leaking the view for a long-running process.
2899 /// It's also given an [`AsyncWindowContext`], which can be used to access the state of the view across await points.
2900 /// The returned future will be polled on the main thread.
2901 pub fn spawn<Fut, R>(
2902 &mut self,
2903 f: impl FnOnce(WeakView<V>, AsyncWindowContext) -> Fut,
2904 ) -> Task<R>
2905 where
2906 R: 'static,
2907 Fut: Future<Output = R> + 'static,
2908 {
2909 let view = self.view().downgrade();
2910 self.window_cx.spawn(|cx| f(view, cx))
2911 }
2912
2913 /// Update the global state of the given type.
2914 pub fn update_global<G, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R
2915 where
2916 G: 'static,
2917 {
2918 let mut global = self.app.lease_global::<G>();
2919 let result = f(&mut global, self);
2920 self.app.end_global_lease(global);
2921 result
2922 }
2923
2924 /// Register a callback to be invoked when the given global state changes.
2925 pub fn observe_global<G: 'static>(
2926 &mut self,
2927 mut f: impl FnMut(&mut V, &mut ViewContext<'_, V>) + 'static,
2928 ) -> Subscription {
2929 let window_handle = self.window.handle;
2930 let view = self.view().downgrade();
2931 let (subscription, activate) = self.global_observers.insert(
2932 TypeId::of::<G>(),
2933 Box::new(move |cx| {
2934 window_handle
2935 .update(cx, |_, cx| view.update(cx, |view, cx| f(view, cx)).is_ok())
2936 .unwrap_or(false)
2937 }),
2938 );
2939 self.app.defer(move |_| activate());
2940 subscription
2941 }
2942
2943 /// Add a listener for any mouse event that occurs in the window.
2944 /// This is a fairly low level method.
2945 /// Typically, you'll want to use methods on UI elements, which perform bounds checking etc.
2946 pub fn on_mouse_event<Event: 'static>(
2947 &mut self,
2948 handler: impl Fn(&mut V, &Event, DispatchPhase, &mut ViewContext<V>) + 'static,
2949 ) {
2950 let handle = self.view().clone();
2951 self.window_cx.on_mouse_event(move |event, phase, cx| {
2952 handle.update(cx, |view, cx| {
2953 handler(view, event, phase, cx);
2954 })
2955 });
2956 }
2957
2958 /// Register a callback to be invoked when the given Key Event is dispatched to the window.
2959 pub fn on_key_event<Event: 'static>(
2960 &mut self,
2961 handler: impl Fn(&mut V, &Event, DispatchPhase, &mut ViewContext<V>) + 'static,
2962 ) {
2963 let handle = self.view().clone();
2964 self.window_cx.on_key_event(move |event, phase, cx| {
2965 handle.update(cx, |view, cx| {
2966 handler(view, event, phase, cx);
2967 })
2968 });
2969 }
2970
2971 /// Register a callback to be invoked when the given Action type is dispatched to the window.
2972 pub fn on_action(
2973 &mut self,
2974 action_type: TypeId,
2975 listener: impl Fn(&mut V, &dyn Any, DispatchPhase, &mut ViewContext<V>) + 'static,
2976 ) {
2977 let handle = self.view().clone();
2978 self.window_cx
2979 .on_action(action_type, move |action, phase, cx| {
2980 handle.update(cx, |view, cx| {
2981 listener(view, action, phase, cx);
2982 })
2983 });
2984 }
2985
2986 /// Emit an event to be handled any other views that have subscribed via [ViewContext::subscribe].
2987 pub fn emit<Evt>(&mut self, event: Evt)
2988 where
2989 Evt: 'static,
2990 V: EventEmitter<Evt>,
2991 {
2992 let emitter = self.view.model.entity_id;
2993 self.app.push_effect(Effect::Emit {
2994 emitter,
2995 event_type: TypeId::of::<Evt>(),
2996 event: Box::new(event),
2997 });
2998 }
2999
3000 /// Move focus to the current view, assuming it implements [`FocusableView`].
3001 pub fn focus_self(&mut self)
3002 where
3003 V: FocusableView,
3004 {
3005 self.defer(|view, cx| view.focus_handle(cx).focus(cx))
3006 }
3007
3008 /// Convenience method for accessing view state in an event callback.
3009 ///
3010 /// Many GPUI callbacks take the form of `Fn(&E, &mut WindowContext)`,
3011 /// but it's often useful to be able to access view state in these
3012 /// callbacks. This method provides a convenient way to do so.
3013 pub fn listener<E>(
3014 &self,
3015 f: impl Fn(&mut V, &E, &mut ViewContext<V>) + 'static,
3016 ) -> impl Fn(&E, &mut WindowContext) + 'static {
3017 let view = self.view().downgrade();
3018 move |e: &E, cx: &mut WindowContext| {
3019 view.update(cx, |view, cx| f(view, e, cx)).ok();
3020 }
3021 }
3022}
3023
3024impl<V> Context for ViewContext<'_, V> {
3025 type Result<U> = U;
3026
3027 fn new_model<T: 'static>(
3028 &mut self,
3029 build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
3030 ) -> Model<T> {
3031 self.window_cx.new_model(build_model)
3032 }
3033
3034 fn update_model<T: 'static, R>(
3035 &mut self,
3036 model: &Model<T>,
3037 update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
3038 ) -> R {
3039 self.window_cx.update_model(model, update)
3040 }
3041
3042 fn update_window<T, F>(&mut self, window: AnyWindowHandle, update: F) -> Result<T>
3043 where
3044 F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
3045 {
3046 self.window_cx.update_window(window, update)
3047 }
3048
3049 fn read_model<T, R>(
3050 &self,
3051 handle: &Model<T>,
3052 read: impl FnOnce(&T, &AppContext) -> R,
3053 ) -> Self::Result<R>
3054 where
3055 T: 'static,
3056 {
3057 self.window_cx.read_model(handle, read)
3058 }
3059
3060 fn read_window<T, R>(
3061 &self,
3062 window: &WindowHandle<T>,
3063 read: impl FnOnce(View<T>, &AppContext) -> R,
3064 ) -> Result<R>
3065 where
3066 T: 'static,
3067 {
3068 self.window_cx.read_window(window, read)
3069 }
3070}
3071
3072impl<V: 'static> VisualContext for ViewContext<'_, V> {
3073 fn new_view<W: Render + 'static>(
3074 &mut self,
3075 build_view_state: impl FnOnce(&mut ViewContext<'_, W>) -> W,
3076 ) -> Self::Result<View<W>> {
3077 self.window_cx.new_view(build_view_state)
3078 }
3079
3080 fn update_view<V2: 'static, R>(
3081 &mut self,
3082 view: &View<V2>,
3083 update: impl FnOnce(&mut V2, &mut ViewContext<'_, V2>) -> R,
3084 ) -> Self::Result<R> {
3085 self.window_cx.update_view(view, update)
3086 }
3087
3088 fn replace_root_view<W>(
3089 &mut self,
3090 build_view: impl FnOnce(&mut ViewContext<'_, W>) -> W,
3091 ) -> Self::Result<View<W>>
3092 where
3093 W: 'static + Render,
3094 {
3095 self.window_cx.replace_root_view(build_view)
3096 }
3097
3098 fn focus_view<W: FocusableView>(&mut self, view: &View<W>) -> Self::Result<()> {
3099 self.window_cx.focus_view(view)
3100 }
3101
3102 fn dismiss_view<W: ManagedView>(&mut self, view: &View<W>) -> Self::Result<()> {
3103 self.window_cx.dismiss_view(view)
3104 }
3105}
3106
3107impl<'a, V> std::ops::Deref for ViewContext<'a, V> {
3108 type Target = WindowContext<'a>;
3109
3110 fn deref(&self) -> &Self::Target {
3111 &self.window_cx
3112 }
3113}
3114
3115impl<'a, V> std::ops::DerefMut for ViewContext<'a, V> {
3116 fn deref_mut(&mut self) -> &mut Self::Target {
3117 &mut self.window_cx
3118 }
3119}
3120
3121// #[derive(Clone, Copy, Eq, PartialEq, Hash)]
3122slotmap::new_key_type! {
3123 /// A unique identifier for a window.
3124 pub struct WindowId;
3125}
3126
3127impl WindowId {
3128 /// Converts this window ID to a `u64`.
3129 pub fn as_u64(&self) -> u64 {
3130 self.0.as_ffi()
3131 }
3132}
3133
3134/// A handle to a window with a specific root view type.
3135/// Note that this does not keep the window alive on its own.
3136#[derive(Deref, DerefMut)]
3137pub struct WindowHandle<V> {
3138 #[deref]
3139 #[deref_mut]
3140 pub(crate) any_handle: AnyWindowHandle,
3141 state_type: PhantomData<V>,
3142}
3143
3144impl<V: 'static + Render> WindowHandle<V> {
3145 /// Create a new handle from a window ID.
3146 /// This does not check if the root type of the window is `V`.
3147 pub fn new(id: WindowId) -> Self {
3148 WindowHandle {
3149 any_handle: AnyWindowHandle {
3150 id,
3151 state_type: TypeId::of::<V>(),
3152 },
3153 state_type: PhantomData,
3154 }
3155 }
3156
3157 /// Get the root view out of this window.
3158 ///
3159 /// This will fail if the window is closed or if the root view's type does not match `V`.
3160 pub fn root<C>(&self, cx: &mut C) -> Result<View<V>>
3161 where
3162 C: Context,
3163 {
3164 Flatten::flatten(cx.update_window(self.any_handle, |root_view, _| {
3165 root_view
3166 .downcast::<V>()
3167 .map_err(|_| anyhow!("the type of the window's root view has changed"))
3168 }))
3169 }
3170
3171 /// Update the root view of this window.
3172 ///
3173 /// This will fail if the window has been closed or if the root view's type does not match
3174 pub fn update<C, R>(
3175 &self,
3176 cx: &mut C,
3177 update: impl FnOnce(&mut V, &mut ViewContext<'_, V>) -> R,
3178 ) -> Result<R>
3179 where
3180 C: Context,
3181 {
3182 cx.update_window(self.any_handle, |root_view, cx| {
3183 let view = root_view
3184 .downcast::<V>()
3185 .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
3186 Ok(cx.update_view(&view, update))
3187 })?
3188 }
3189
3190 /// Read the root view out of this window.
3191 ///
3192 /// This will fail if the window is closed or if the root view's type does not match `V`.
3193 pub fn read<'a>(&self, cx: &'a AppContext) -> Result<&'a V> {
3194 let x = cx
3195 .windows
3196 .get(self.id)
3197 .and_then(|window| {
3198 window
3199 .as_ref()
3200 .and_then(|window| window.root_view.clone())
3201 .map(|root_view| root_view.downcast::<V>())
3202 })
3203 .ok_or_else(|| anyhow!("window not found"))?
3204 .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
3205
3206 Ok(x.read(cx))
3207 }
3208
3209 /// Read the root view out of this window, with a callback
3210 ///
3211 /// This will fail if the window is closed or if the root view's type does not match `V`.
3212 pub fn read_with<C, R>(&self, cx: &C, read_with: impl FnOnce(&V, &AppContext) -> R) -> Result<R>
3213 where
3214 C: Context,
3215 {
3216 cx.read_window(self, |root_view, cx| read_with(root_view.read(cx), cx))
3217 }
3218
3219 /// Read the root view pointer off of this window.
3220 ///
3221 /// This will fail if the window is closed or if the root view's type does not match `V`.
3222 pub fn root_view<C>(&self, cx: &C) -> Result<View<V>>
3223 where
3224 C: Context,
3225 {
3226 cx.read_window(self, |root_view, _cx| root_view.clone())
3227 }
3228
3229 /// Check if this window is 'active'.
3230 ///
3231 /// Will return `None` if the window is closed.
3232 pub fn is_active(&self, cx: &AppContext) -> Option<bool> {
3233 cx.windows
3234 .get(self.id)
3235 .and_then(|window| window.as_ref().map(|window| window.active))
3236 }
3237}
3238
3239impl<V> Copy for WindowHandle<V> {}
3240
3241impl<V> Clone for WindowHandle<V> {
3242 fn clone(&self) -> Self {
3243 *self
3244 }
3245}
3246
3247impl<V> PartialEq for WindowHandle<V> {
3248 fn eq(&self, other: &Self) -> bool {
3249 self.any_handle == other.any_handle
3250 }
3251}
3252
3253impl<V> Eq for WindowHandle<V> {}
3254
3255impl<V> Hash for WindowHandle<V> {
3256 fn hash<H: Hasher>(&self, state: &mut H) {
3257 self.any_handle.hash(state);
3258 }
3259}
3260
3261impl<V: 'static> From<WindowHandle<V>> for AnyWindowHandle {
3262 fn from(val: WindowHandle<V>) -> Self {
3263 val.any_handle
3264 }
3265}
3266
3267/// A handle to a window with any root view type, which can be downcast to a window with a specific root view type.
3268#[derive(Copy, Clone, PartialEq, Eq, Hash)]
3269pub struct AnyWindowHandle {
3270 pub(crate) id: WindowId,
3271 state_type: TypeId,
3272}
3273
3274impl AnyWindowHandle {
3275 /// Get the ID of this window.
3276 pub fn window_id(&self) -> WindowId {
3277 self.id
3278 }
3279
3280 /// Attempt to convert this handle to a window handle with a specific root view type.
3281 /// If the types do not match, this will return `None`.
3282 pub fn downcast<T: 'static>(&self) -> Option<WindowHandle<T>> {
3283 if TypeId::of::<T>() == self.state_type {
3284 Some(WindowHandle {
3285 any_handle: *self,
3286 state_type: PhantomData,
3287 })
3288 } else {
3289 None
3290 }
3291 }
3292
3293 /// Update the state of the root view of this window.
3294 ///
3295 /// This will fail if the window has been closed.
3296 pub fn update<C, R>(
3297 self,
3298 cx: &mut C,
3299 update: impl FnOnce(AnyView, &mut WindowContext<'_>) -> R,
3300 ) -> Result<R>
3301 where
3302 C: Context,
3303 {
3304 cx.update_window(self, update)
3305 }
3306
3307 /// Read the state of the root view of this window.
3308 ///
3309 /// This will fail if the window has been closed.
3310 pub fn read<T, C, R>(self, cx: &C, read: impl FnOnce(View<T>, &AppContext) -> R) -> Result<R>
3311 where
3312 C: Context,
3313 T: 'static,
3314 {
3315 let view = self
3316 .downcast::<T>()
3317 .context("the type of the window's root view has changed")?;
3318
3319 cx.read_window(&view, read)
3320 }
3321}
3322
3323/// An identifier for an [`Element`](crate::Element).
3324///
3325/// Can be constructed with a string, a number, or both, as well
3326/// as other internal representations.
3327#[derive(Clone, Debug, Eq, PartialEq, Hash)]
3328pub enum ElementId {
3329 /// The ID of a View element
3330 View(EntityId),
3331 /// An integer ID.
3332 Integer(usize),
3333 /// A string based ID.
3334 Name(SharedString),
3335 /// An ID that's equated with a focus handle.
3336 FocusHandle(FocusId),
3337 /// A combination of a name and an integer.
3338 NamedInteger(SharedString, usize),
3339}
3340
3341impl ElementId {
3342 pub(crate) fn from_entity_id(entity_id: EntityId) -> Self {
3343 ElementId::View(entity_id)
3344 }
3345}
3346
3347impl TryInto<SharedString> for ElementId {
3348 type Error = anyhow::Error;
3349
3350 fn try_into(self) -> anyhow::Result<SharedString> {
3351 if let ElementId::Name(name) = self {
3352 Ok(name)
3353 } else {
3354 Err(anyhow!("element id is not string"))
3355 }
3356 }
3357}
3358
3359impl From<usize> for ElementId {
3360 fn from(id: usize) -> Self {
3361 ElementId::Integer(id)
3362 }
3363}
3364
3365impl From<i32> for ElementId {
3366 fn from(id: i32) -> Self {
3367 Self::Integer(id as usize)
3368 }
3369}
3370
3371impl From<SharedString> for ElementId {
3372 fn from(name: SharedString) -> Self {
3373 ElementId::Name(name)
3374 }
3375}
3376
3377impl From<&'static str> for ElementId {
3378 fn from(name: &'static str) -> Self {
3379 ElementId::Name(name.into())
3380 }
3381}
3382
3383impl<'a> From<&'a FocusHandle> for ElementId {
3384 fn from(handle: &'a FocusHandle) -> Self {
3385 ElementId::FocusHandle(handle.id)
3386 }
3387}
3388
3389impl From<(&'static str, EntityId)> for ElementId {
3390 fn from((name, id): (&'static str, EntityId)) -> Self {
3391 ElementId::NamedInteger(name.into(), id.as_u64() as usize)
3392 }
3393}
3394
3395impl From<(&'static str, usize)> for ElementId {
3396 fn from((name, id): (&'static str, usize)) -> Self {
3397 ElementId::NamedInteger(name.into(), id)
3398 }
3399}
3400
3401impl From<(&'static str, u64)> for ElementId {
3402 fn from((name, id): (&'static str, u64)) -> Self {
3403 ElementId::NamedInteger(name.into(), id as usize)
3404 }
3405}
3406
3407/// A rectangle to be rendered in the window at the given position and size.
3408/// Passed as an argument [`WindowContext::paint_quad`].
3409#[derive(Clone)]
3410pub struct PaintQuad {
3411 bounds: Bounds<Pixels>,
3412 corner_radii: Corners<Pixels>,
3413 background: Hsla,
3414 border_widths: Edges<Pixels>,
3415 border_color: Hsla,
3416}
3417
3418impl PaintQuad {
3419 /// Set the corner radii of the quad.
3420 pub fn corner_radii(self, corner_radii: impl Into<Corners<Pixels>>) -> Self {
3421 PaintQuad {
3422 corner_radii: corner_radii.into(),
3423 ..self
3424 }
3425 }
3426
3427 /// Set the border widths of the quad.
3428 pub fn border_widths(self, border_widths: impl Into<Edges<Pixels>>) -> Self {
3429 PaintQuad {
3430 border_widths: border_widths.into(),
3431 ..self
3432 }
3433 }
3434
3435 /// Set the border color of the quad.
3436 pub fn border_color(self, border_color: impl Into<Hsla>) -> Self {
3437 PaintQuad {
3438 border_color: border_color.into(),
3439 ..self
3440 }
3441 }
3442
3443 /// Set the background color of the quad.
3444 pub fn background(self, background: impl Into<Hsla>) -> Self {
3445 PaintQuad {
3446 background: background.into(),
3447 ..self
3448 }
3449 }
3450}
3451
3452/// Create a quad with the given parameters.
3453pub fn quad(
3454 bounds: Bounds<Pixels>,
3455 corner_radii: impl Into<Corners<Pixels>>,
3456 background: impl Into<Hsla>,
3457 border_widths: impl Into<Edges<Pixels>>,
3458 border_color: impl Into<Hsla>,
3459) -> PaintQuad {
3460 PaintQuad {
3461 bounds,
3462 corner_radii: corner_radii.into(),
3463 background: background.into(),
3464 border_widths: border_widths.into(),
3465 border_color: border_color.into(),
3466 }
3467}
3468
3469/// Create a filled quad with the given bounds and background color.
3470pub fn fill(bounds: impl Into<Bounds<Pixels>>, background: impl Into<Hsla>) -> PaintQuad {
3471 PaintQuad {
3472 bounds: bounds.into(),
3473 corner_radii: (0.).into(),
3474 background: background.into(),
3475 border_widths: (0.).into(),
3476 border_color: transparent_black(),
3477 }
3478}
3479
3480/// Create a rectangle outline with the given bounds, border color, and a 1px border width
3481pub fn outline(bounds: impl Into<Bounds<Pixels>>, border_color: impl Into<Hsla>) -> PaintQuad {
3482 PaintQuad {
3483 bounds: bounds.into(),
3484 corner_radii: (0.).into(),
3485 background: transparent_black(),
3486 border_widths: (1.).into(),
3487 border_color: border_color.into(),
3488 }
3489}