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