1use crate::{
2 px, size, Action, AnyBox, AnyDrag, AnyView, AppContext, AsyncWindowContext, AvailableSpace,
3 Bounds, BoxShadow, Context, Corners, CursorStyle, DevicePixels, DispatchContext, DisplayId,
4 Edges, Effect, Entity, EntityId, EventEmitter, FileDropEvent, FocusEvent, FontId,
5 GlobalElementId, GlyphId, Hsla, ImageData, InputEvent, IsZero, KeyListener, KeyMatch,
6 KeyMatcher, Keystroke, LayoutId, Model, ModelContext, Modifiers, MonochromeSprite, MouseButton,
7 MouseDownEvent, MouseMoveEvent, MouseUpEvent, Path, Pixels, PlatformAtlas, PlatformDisplay,
8 PlatformInputHandler, PlatformWindow, Point, PolychromeSprite, PromptLevel, Quad, Render,
9 RenderGlyphParams, RenderImageParams, RenderSvgParams, ScaledPixels, SceneBuilder, Shadow,
10 SharedString, Size, Style, SubscriberSet, Subscription, TaffyLayoutEngine, Task, Underline,
11 UnderlineStyle, View, VisualContext, WeakView, WindowBounds, WindowOptions, SUBPIXEL_VARIANTS,
12};
13use anyhow::{anyhow, Result};
14use collections::HashMap;
15use derive_more::{Deref, DerefMut};
16use futures::{
17 channel::{mpsc, oneshot},
18 StreamExt,
19};
20use parking_lot::RwLock;
21use slotmap::SlotMap;
22use smallvec::SmallVec;
23use std::{
24 any::{Any, TypeId},
25 borrow::{Borrow, BorrowMut, Cow},
26 fmt::Debug,
27 future::Future,
28 hash::{Hash, Hasher},
29 marker::PhantomData,
30 mem,
31 rc::Rc,
32 sync::{
33 atomic::{AtomicUsize, Ordering::SeqCst},
34 Arc,
35 },
36};
37use util::ResultExt;
38
39/// A global stacking order, which is created by stacking successive z-index values.
40/// Each z-index will always be interpreted in the context of its parent z-index.
41#[derive(Deref, DerefMut, Ord, PartialOrd, Eq, PartialEq, Clone, Default)]
42pub(crate) struct StackingOrder(pub(crate) SmallVec<[u32; 16]>);
43
44/// Represents the two different phases when dispatching events.
45#[derive(Default, Copy, Clone, Debug, Eq, PartialEq)]
46pub enum DispatchPhase {
47 /// After the capture phase comes the bubble phase, in which mouse event listeners are
48 /// invoked front to back and keyboard event listeners are invoked from the focused element
49 /// to the root of the element tree. This is the phase you'll most commonly want to use when
50 /// registering event listeners.
51 #[default]
52 Bubble,
53 /// During the initial capture phase, mouse event listeners are invoked back to front, and keyboard
54 /// listeners are invoked from the root of the tree downward toward the focused element. This phase
55 /// is used for special purposes such as clearing the "pressed" state for click events. If
56 /// you stop event propagation during this phase, you need to know what you're doing. Handlers
57 /// outside of the immediate region may rely on detecting non-local events during this phase.
58 Capture,
59}
60
61type AnyObserver = Box<dyn FnMut(&mut WindowContext) -> bool + 'static>;
62type AnyListener = Box<dyn FnMut(&dyn Any, DispatchPhase, &mut WindowContext) + 'static>;
63type AnyKeyListener = Box<
64 dyn Fn(
65 &dyn Any,
66 &[&DispatchContext],
67 DispatchPhase,
68 &mut WindowContext,
69 ) -> Option<Box<dyn Action>>
70 + 'static,
71>;
72type AnyFocusListener = Box<dyn Fn(&FocusEvent, &mut WindowContext) + 'static>;
73type AnyWindowFocusListener = Box<dyn FnMut(&FocusEvent, &mut WindowContext) -> bool + 'static>;
74
75slotmap::new_key_type! { pub struct FocusId; }
76
77impl FocusId {
78 /// Obtains whether the element associated with this handle is currently focused.
79 pub fn is_focused(&self, cx: &WindowContext) -> bool {
80 cx.window.focus == Some(*self)
81 }
82
83 /// Obtains whether the element associated with this handle contains the focused
84 /// element or is itself focused.
85 pub fn contains_focused(&self, cx: &WindowContext) -> bool {
86 cx.focused()
87 .map_or(false, |focused| self.contains(focused.id, cx))
88 }
89
90 /// Obtains whether the element associated with this handle is contained within the
91 /// focused element or is itself focused.
92 pub fn within_focused(&self, cx: &WindowContext) -> bool {
93 let focused = cx.focused();
94 focused.map_or(false, |focused| focused.id.contains(*self, cx))
95 }
96
97 /// Obtains whether this handle contains the given handle in the most recently rendered frame.
98 pub(crate) fn contains(&self, other: Self, cx: &WindowContext) -> bool {
99 let mut ancestor = Some(other);
100 while let Some(ancestor_id) = ancestor {
101 if *self == ancestor_id {
102 return true;
103 } else {
104 ancestor = cx
105 .window
106 .current_frame
107 .focus_parents_by_child
108 .get(&ancestor_id)
109 .copied();
110 }
111 }
112 false
113 }
114}
115
116/// A handle which can be used to track and manipulate the focused element in a window.
117pub struct FocusHandle {
118 pub(crate) id: FocusId,
119 handles: Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>,
120}
121
122impl FocusHandle {
123 pub(crate) fn new(handles: &Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>) -> Self {
124 let id = handles.write().insert(AtomicUsize::new(1));
125 Self {
126 id,
127 handles: handles.clone(),
128 }
129 }
130
131 pub(crate) fn for_id(
132 id: FocusId,
133 handles: &Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>,
134 ) -> Option<Self> {
135 let lock = handles.read();
136 let ref_count = lock.get(id)?;
137 if ref_count.load(SeqCst) == 0 {
138 None
139 } else {
140 ref_count.fetch_add(1, SeqCst);
141 Some(Self {
142 id,
143 handles: handles.clone(),
144 })
145 }
146 }
147
148 /// Obtains whether the element associated with this handle is currently focused.
149 pub fn is_focused(&self, cx: &WindowContext) -> bool {
150 self.id.is_focused(cx)
151 }
152
153 /// Obtains whether the element associated with this handle contains the focused
154 /// element or is itself focused.
155 pub fn contains_focused(&self, cx: &WindowContext) -> bool {
156 self.id.contains_focused(cx)
157 }
158
159 /// Obtains whether the element associated with this handle is contained within the
160 /// focused element or is itself focused.
161 pub fn within_focused(&self, cx: &WindowContext) -> bool {
162 self.id.within_focused(cx)
163 }
164
165 /// Obtains whether this handle contains the given handle in the most recently rendered frame.
166 pub(crate) fn contains(&self, other: &Self, cx: &WindowContext) -> bool {
167 self.id.contains(other.id, cx)
168 }
169}
170
171impl Clone for FocusHandle {
172 fn clone(&self) -> Self {
173 Self::for_id(self.id, &self.handles).unwrap()
174 }
175}
176
177impl PartialEq for FocusHandle {
178 fn eq(&self, other: &Self) -> bool {
179 self.id == other.id
180 }
181}
182
183impl Eq for FocusHandle {}
184
185impl Drop for FocusHandle {
186 fn drop(&mut self) {
187 self.handles
188 .read()
189 .get(self.id)
190 .unwrap()
191 .fetch_sub(1, SeqCst);
192 }
193}
194
195// Holds the state for a specific window.
196pub struct Window {
197 pub(crate) handle: AnyWindowHandle,
198 pub(crate) removed: bool,
199 platform_window: Box<dyn PlatformWindow>,
200 display_id: DisplayId,
201 sprite_atlas: Arc<dyn PlatformAtlas>,
202 rem_size: Pixels,
203 content_size: Size<Pixels>,
204 pub(crate) layout_engine: TaffyLayoutEngine,
205 pub(crate) root_view: Option<AnyView>,
206 pub(crate) element_id_stack: GlobalElementId,
207 pub(crate) previous_frame: Frame,
208 pub(crate) current_frame: Frame,
209 pub(crate) focus_handles: Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>,
210 pub(crate) focus_listeners: SubscriberSet<(), AnyWindowFocusListener>,
211 default_prevented: bool,
212 mouse_position: Point<Pixels>,
213 requested_cursor_style: Option<CursorStyle>,
214 scale_factor: f32,
215 bounds: WindowBounds,
216 bounds_observers: SubscriberSet<(), AnyObserver>,
217 active: bool,
218 activation_observers: SubscriberSet<(), AnyObserver>,
219 pub(crate) dirty: bool,
220 pub(crate) last_blur: Option<Option<FocusId>>,
221 pub(crate) focus: Option<FocusId>,
222}
223
224#[derive(Default)]
225pub(crate) struct Frame {
226 element_states: HashMap<GlobalElementId, AnyBox>,
227 key_matchers: HashMap<GlobalElementId, KeyMatcher>,
228 mouse_listeners: HashMap<TypeId, Vec<(StackingOrder, AnyListener)>>,
229 pub(crate) focus_listeners: Vec<AnyFocusListener>,
230 key_dispatch_stack: Vec<KeyDispatchStackFrame>,
231 freeze_key_dispatch_stack: bool,
232 focus_parents_by_child: HashMap<FocusId, FocusId>,
233 pub(crate) scene_builder: SceneBuilder,
234 z_index_stack: StackingOrder,
235 content_mask_stack: Vec<ContentMask<Pixels>>,
236 element_offset_stack: Vec<Point<Pixels>>,
237 focus_stack: Vec<FocusId>,
238}
239
240impl Window {
241 pub(crate) fn new(
242 handle: AnyWindowHandle,
243 options: WindowOptions,
244 cx: &mut AppContext,
245 ) -> Self {
246 let platform_window = cx.platform.open_window(handle, options);
247 let display_id = platform_window.display().id();
248 let sprite_atlas = platform_window.sprite_atlas();
249 let mouse_position = platform_window.mouse_position();
250 let content_size = platform_window.content_size();
251 let scale_factor = platform_window.scale_factor();
252 let bounds = platform_window.bounds();
253
254 platform_window.on_resize(Box::new({
255 let mut cx = cx.to_async();
256 move |_, _| {
257 handle
258 .update(&mut cx, |_, cx| cx.window_bounds_changed())
259 .log_err();
260 }
261 }));
262 platform_window.on_moved(Box::new({
263 let mut cx = cx.to_async();
264 move || {
265 handle
266 .update(&mut cx, |_, cx| cx.window_bounds_changed())
267 .log_err();
268 }
269 }));
270 platform_window.on_active_status_change(Box::new({
271 let mut cx = cx.to_async();
272 move |active| {
273 handle
274 .update(&mut cx, |_, cx| {
275 cx.window.active = active;
276 cx.window
277 .activation_observers
278 .clone()
279 .retain(&(), |callback| callback(cx));
280 })
281 .log_err();
282 }
283 }));
284
285 platform_window.on_input({
286 let mut cx = cx.to_async();
287 Box::new(move |event| {
288 handle
289 .update(&mut cx, |_, cx| cx.dispatch_event(event))
290 .log_err()
291 .unwrap_or(false)
292 })
293 });
294
295 Window {
296 handle,
297 removed: false,
298 platform_window,
299 display_id,
300 sprite_atlas,
301 rem_size: px(16.),
302 content_size,
303 layout_engine: TaffyLayoutEngine::new(),
304 root_view: None,
305 element_id_stack: GlobalElementId::default(),
306 previous_frame: Frame::default(),
307 current_frame: Frame::default(),
308 focus_handles: Arc::new(RwLock::new(SlotMap::with_key())),
309 focus_listeners: SubscriberSet::new(),
310 default_prevented: true,
311 mouse_position,
312 requested_cursor_style: None,
313 scale_factor,
314 bounds,
315 bounds_observers: SubscriberSet::new(),
316 active: false,
317 activation_observers: SubscriberSet::new(),
318 dirty: true,
319 last_blur: None,
320 focus: None,
321 }
322 }
323}
324
325/// When constructing the element tree, we maintain a stack of key dispatch frames until we
326/// find the focused element. We interleave key listeners with dispatch contexts so we can use the
327/// contexts when matching key events against the keymap. A key listener can be either an action
328/// handler or a [KeyDown] / [KeyUp] event listener.
329enum KeyDispatchStackFrame {
330 Listener {
331 event_type: TypeId,
332 listener: AnyKeyListener,
333 },
334 Context(DispatchContext),
335}
336
337/// Indicates which region of the window is visible. Content falling outside of this mask will not be
338/// rendered. Currently, only rectangular content masks are supported, but we give the mask its own type
339/// to leave room to support more complex shapes in the future.
340#[derive(Clone, Debug, Default, PartialEq, Eq)]
341#[repr(C)]
342pub struct ContentMask<P: Clone + Default + Debug> {
343 pub bounds: Bounds<P>,
344}
345
346impl ContentMask<Pixels> {
347 /// Scale the content mask's pixel units by the given scaling factor.
348 pub fn scale(&self, factor: f32) -> ContentMask<ScaledPixels> {
349 ContentMask {
350 bounds: self.bounds.scale(factor),
351 }
352 }
353
354 /// Intersect the content mask with the given content mask.
355 pub fn intersect(&self, other: &Self) -> Self {
356 let bounds = self.bounds.intersect(&other.bounds);
357 ContentMask { bounds }
358 }
359}
360
361/// Provides access to application state in the context of a single window. Derefs
362/// to an `AppContext`, so you can also pass a `WindowContext` to any method that takes
363/// an `AppContext` and call any `AppContext` methods.
364pub struct WindowContext<'a> {
365 pub(crate) app: &'a mut AppContext,
366 pub(crate) window: &'a mut Window,
367}
368
369impl<'a> WindowContext<'a> {
370 pub(crate) fn new(app: &'a mut AppContext, window: &'a mut Window) -> Self {
371 Self { app, window }
372 }
373
374 /// Obtain a handle to the window that belongs to this context.
375 pub fn window_handle(&self) -> AnyWindowHandle {
376 self.window.handle
377 }
378
379 /// Mark the window as dirty, scheduling it to be redrawn on the next frame.
380 pub fn notify(&mut self) {
381 self.window.dirty = true;
382 }
383
384 /// Close this window.
385 pub fn remove_window(&mut self) {
386 self.window.removed = true;
387 }
388
389 /// Obtain a new `FocusHandle`, which allows you to track and manipulate the keyboard focus
390 /// for elements rendered within this window.
391 pub fn focus_handle(&mut self) -> FocusHandle {
392 FocusHandle::new(&self.window.focus_handles)
393 }
394
395 /// Obtain the currently focused `FocusHandle`. If no elements are focused, returns `None`.
396 pub fn focused(&self) -> Option<FocusHandle> {
397 self.window
398 .focus
399 .and_then(|id| FocusHandle::for_id(id, &self.window.focus_handles))
400 }
401
402 /// Move focus to the element associated with the given `FocusHandle`.
403 pub fn focus(&mut self, handle: &FocusHandle) {
404 if self.window.last_blur.is_none() {
405 self.window.last_blur = Some(self.window.focus);
406 }
407
408 self.window.focus = Some(handle.id);
409 self.app.push_effect(Effect::FocusChanged {
410 window_handle: self.window.handle,
411 focused: Some(handle.id),
412 });
413 self.notify();
414 }
415
416 /// Remove focus from all elements within this context's window.
417 pub fn blur(&mut self) {
418 if self.window.last_blur.is_none() {
419 self.window.last_blur = Some(self.window.focus);
420 }
421
422 self.window.focus = None;
423 self.app.push_effect(Effect::FocusChanged {
424 window_handle: self.window.handle,
425 focused: None,
426 });
427 self.notify();
428 }
429
430 /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
431 /// that are currently on the stack to be returned to the app.
432 pub fn defer(&mut self, f: impl FnOnce(&mut WindowContext) + 'static) {
433 let handle = self.window.handle;
434 self.app.defer(move |cx| {
435 handle.update(cx, |_, cx| f(cx)).ok();
436 });
437 }
438
439 pub fn subscribe<Emitter, E, Evt>(
440 &mut self,
441 entity: &E,
442 mut on_event: impl FnMut(E, &Evt, &mut WindowContext<'_>) + 'static,
443 ) -> Subscription
444 where
445 Emitter: EventEmitter<Evt>,
446 E: Entity<Emitter>,
447 Evt: 'static,
448 {
449 let entity_id = entity.entity_id();
450 let entity = entity.downgrade();
451 let window_handle = self.window.handle;
452 self.app.event_listeners.insert(
453 entity_id,
454 (
455 TypeId::of::<Evt>(),
456 Box::new(move |event, cx| {
457 window_handle
458 .update(cx, |_, cx| {
459 if let Some(handle) = E::upgrade_from(&entity) {
460 let event = event.downcast_ref().expect("invalid event type");
461 on_event(handle, event, cx);
462 true
463 } else {
464 false
465 }
466 })
467 .unwrap_or(false)
468 }),
469 ),
470 )
471 }
472
473 /// Create an `AsyncWindowContext`, which has a static lifetime and can be held across
474 /// await points in async code.
475 pub fn to_async(&self) -> AsyncWindowContext {
476 AsyncWindowContext::new(self.app.to_async(), self.window.handle)
477 }
478
479 /// Schedule the given closure to be run directly after the current frame is rendered.
480 pub fn on_next_frame(&mut self, callback: impl FnOnce(&mut WindowContext) + 'static) {
481 let handle = self.window.handle;
482 let display_id = self.window.display_id;
483
484 if !self.frame_consumers.contains_key(&display_id) {
485 let (tx, mut rx) = mpsc::unbounded::<()>();
486 self.platform.set_display_link_output_callback(
487 display_id,
488 Box::new(move |_current_time, _output_time| _ = tx.unbounded_send(())),
489 );
490
491 let consumer_task = self.app.spawn(|cx| async move {
492 while rx.next().await.is_some() {
493 cx.update(|cx| {
494 for callback in cx
495 .next_frame_callbacks
496 .get_mut(&display_id)
497 .unwrap()
498 .drain(..)
499 .collect::<SmallVec<[_; 32]>>()
500 {
501 callback(cx);
502 }
503 })
504 .ok();
505
506 // Flush effects, then stop the display link if no new next_frame_callbacks have been added.
507
508 cx.update(|cx| {
509 if cx.next_frame_callbacks.is_empty() {
510 cx.platform.stop_display_link(display_id);
511 }
512 })
513 .ok();
514 }
515 });
516 self.frame_consumers.insert(display_id, consumer_task);
517 }
518
519 if self.next_frame_callbacks.is_empty() {
520 self.platform.start_display_link(display_id);
521 }
522
523 self.next_frame_callbacks
524 .entry(display_id)
525 .or_default()
526 .push(Box::new(move |cx: &mut AppContext| {
527 cx.update_window(handle, |_root_view, cx| callback(cx)).ok();
528 }));
529 }
530
531 /// Spawn the future returned by the given closure on the application thread pool.
532 /// The closure is provided a handle to the current window and an `AsyncWindowContext` for
533 /// use within your future.
534 pub fn spawn<Fut, R>(&mut self, f: impl FnOnce(AsyncWindowContext) -> Fut) -> Task<R>
535 where
536 R: 'static,
537 Fut: Future<Output = R> + 'static,
538 {
539 self.app
540 .spawn(|app| f(AsyncWindowContext::new(app, self.window.handle)))
541 }
542
543 /// Update the global of the given type. The given closure is given simultaneous mutable
544 /// access both to the global and the context.
545 pub fn update_global<G, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R
546 where
547 G: 'static,
548 {
549 let mut global = self.app.lease_global::<G>();
550 let result = f(&mut global, self);
551 self.app.end_global_lease(global);
552 result
553 }
554
555 /// Add a node to the layout tree for the current frame. Takes the `Style` of the element for which
556 /// layout is being requested, along with the layout ids of any children. This method is called during
557 /// calls to the `Element::layout` trait method and enables any element to participate in layout.
558 pub fn request_layout(
559 &mut self,
560 style: &Style,
561 children: impl IntoIterator<Item = LayoutId>,
562 ) -> LayoutId {
563 self.app.layout_id_buffer.clear();
564 self.app.layout_id_buffer.extend(children.into_iter());
565 let rem_size = self.rem_size();
566
567 self.window
568 .layout_engine
569 .request_layout(style, rem_size, &self.app.layout_id_buffer)
570 }
571
572 /// Add a node to the layout tree for the current frame. Instead of taking a `Style` and children,
573 /// this variant takes a function that is invoked during layout so you can use arbitrary logic to
574 /// determine the element's size. One place this is used internally is when measuring text.
575 ///
576 /// The given closure is invoked at layout time with the known dimensions and available space and
577 /// returns a `Size`.
578 pub fn request_measured_layout<
579 F: Fn(Size<Option<Pixels>>, Size<AvailableSpace>) -> Size<Pixels> + Send + Sync + 'static,
580 >(
581 &mut self,
582 style: Style,
583 rem_size: Pixels,
584 measure: F,
585 ) -> LayoutId {
586 self.window
587 .layout_engine
588 .request_measured_layout(style, rem_size, measure)
589 }
590
591 pub fn compute_layout(&mut self, layout_id: LayoutId, available_space: Size<AvailableSpace>) {
592 self.window
593 .layout_engine
594 .compute_layout(layout_id, available_space)
595 }
596
597 /// Obtain the bounds computed for the given LayoutId relative to the window. This method should not
598 /// be invoked until the paint phase begins, and will usually be invoked by GPUI itself automatically
599 /// in order to pass your element its `Bounds` automatically.
600 pub fn layout_bounds(&mut self, layout_id: LayoutId) -> Bounds<Pixels> {
601 let mut bounds = self
602 .window
603 .layout_engine
604 .layout_bounds(layout_id)
605 .map(Into::into);
606 bounds.origin += self.element_offset();
607 bounds
608 }
609
610 fn window_bounds_changed(&mut self) {
611 self.window.scale_factor = self.window.platform_window.scale_factor();
612 self.window.content_size = self.window.platform_window.content_size();
613 self.window.bounds = self.window.platform_window.bounds();
614 self.window.display_id = self.window.platform_window.display().id();
615 self.window.dirty = true;
616
617 self.window
618 .bounds_observers
619 .clone()
620 .retain(&(), |callback| callback(self));
621 }
622
623 pub fn window_bounds(&self) -> WindowBounds {
624 self.window.bounds
625 }
626
627 pub fn is_window_active(&self) -> bool {
628 self.window.active
629 }
630
631 pub fn zoom_window(&self) {
632 self.window.platform_window.zoom();
633 }
634
635 pub fn display(&self) -> Option<Rc<dyn PlatformDisplay>> {
636 self.platform
637 .displays()
638 .into_iter()
639 .find(|display| display.id() == self.window.display_id)
640 }
641
642 pub fn show_character_palette(&self) {
643 self.window.platform_window.show_character_palette();
644 }
645
646 /// The scale factor of the display associated with the window. For example, it could
647 /// return 2.0 for a "retina" display, indicating that each logical pixel should actually
648 /// be rendered as two pixels on screen.
649 pub fn scale_factor(&self) -> f32 {
650 self.window.scale_factor
651 }
652
653 /// The size of an em for the base font of the application. Adjusting this value allows the
654 /// UI to scale, just like zooming a web page.
655 pub fn rem_size(&self) -> Pixels {
656 self.window.rem_size
657 }
658
659 /// Sets the size of an em for the base font of the application. Adjusting this value allows the
660 /// UI to scale, just like zooming a web page.
661 pub fn set_rem_size(&mut self, rem_size: impl Into<Pixels>) {
662 self.window.rem_size = rem_size.into();
663 }
664
665 /// The line height associated with the current text style.
666 pub fn line_height(&self) -> Pixels {
667 let rem_size = self.rem_size();
668 let text_style = self.text_style();
669 text_style
670 .line_height
671 .to_pixels(text_style.font_size.into(), rem_size)
672 }
673
674 /// Call to prevent the default action of an event. Currently only used to prevent
675 /// parent elements from becoming focused on mouse down.
676 pub fn prevent_default(&mut self) {
677 self.window.default_prevented = true;
678 }
679
680 /// Obtain whether default has been prevented for the event currently being dispatched.
681 pub fn default_prevented(&self) -> bool {
682 self.window.default_prevented
683 }
684
685 /// Register a mouse event listener on the window for the current frame. The type of event
686 /// is determined by the first parameter of the given listener. When the next frame is rendered
687 /// the listener will be cleared.
688 ///
689 /// This is a fairly low-level method, so prefer using event handlers on elements unless you have
690 /// a specific need to register a global listener.
691 pub fn on_mouse_event<Event: 'static>(
692 &mut self,
693 handler: impl Fn(&Event, DispatchPhase, &mut WindowContext) + 'static,
694 ) {
695 let order = self.window.current_frame.z_index_stack.clone();
696 self.window
697 .current_frame
698 .mouse_listeners
699 .entry(TypeId::of::<Event>())
700 .or_default()
701 .push((
702 order,
703 Box::new(move |event: &dyn Any, phase, cx| {
704 handler(event.downcast_ref().unwrap(), phase, cx)
705 }),
706 ))
707 }
708
709 /// The position of the mouse relative to the window.
710 pub fn mouse_position(&self) -> Point<Pixels> {
711 self.window.mouse_position
712 }
713
714 pub fn set_cursor_style(&mut self, style: CursorStyle) {
715 self.window.requested_cursor_style = Some(style)
716 }
717
718 /// Called during painting to invoke the given closure in a new stacking context. The given
719 /// z-index is interpreted relative to the previous call to `stack`.
720 pub fn stack<R>(&mut self, z_index: u32, f: impl FnOnce(&mut Self) -> R) -> R {
721 self.window.current_frame.z_index_stack.push(z_index);
722 let result = f(self);
723 self.window.current_frame.z_index_stack.pop();
724 result
725 }
726
727 /// Paint one or more drop shadows into the scene for the current frame at the current z-index.
728 pub fn paint_shadows(
729 &mut self,
730 bounds: Bounds<Pixels>,
731 corner_radii: Corners<Pixels>,
732 shadows: &[BoxShadow],
733 ) {
734 let scale_factor = self.scale_factor();
735 let content_mask = self.content_mask();
736 let window = &mut *self.window;
737 for shadow in shadows {
738 let mut shadow_bounds = bounds;
739 shadow_bounds.origin += shadow.offset;
740 shadow_bounds.dilate(shadow.spread_radius);
741 window.current_frame.scene_builder.insert(
742 &window.current_frame.z_index_stack,
743 Shadow {
744 order: 0,
745 bounds: shadow_bounds.scale(scale_factor),
746 content_mask: content_mask.scale(scale_factor),
747 corner_radii: corner_radii.scale(scale_factor),
748 color: shadow.color,
749 blur_radius: shadow.blur_radius.scale(scale_factor),
750 },
751 );
752 }
753 }
754
755 /// Paint one or more quads into the scene for the current frame at the current stacking context.
756 /// Quads are colored rectangular regions with an optional background, border, and corner radius.
757 pub fn paint_quad(
758 &mut self,
759 bounds: Bounds<Pixels>,
760 corner_radii: Corners<Pixels>,
761 background: impl Into<Hsla>,
762 border_widths: Edges<Pixels>,
763 border_color: impl Into<Hsla>,
764 ) {
765 let scale_factor = self.scale_factor();
766 let content_mask = self.content_mask();
767
768 let window = &mut *self.window;
769 window.current_frame.scene_builder.insert(
770 &window.current_frame.z_index_stack,
771 Quad {
772 order: 0,
773 bounds: bounds.scale(scale_factor),
774 content_mask: content_mask.scale(scale_factor),
775 background: background.into(),
776 border_color: border_color.into(),
777 corner_radii: corner_radii.scale(scale_factor),
778 border_widths: border_widths.scale(scale_factor),
779 },
780 );
781 }
782
783 /// Paint the given `Path` into the scene for the current frame at the current z-index.
784 pub fn paint_path(&mut self, mut path: Path<Pixels>, color: impl Into<Hsla>) {
785 let scale_factor = self.scale_factor();
786 let content_mask = self.content_mask();
787 path.content_mask = content_mask;
788 path.color = color.into();
789 let window = &mut *self.window;
790 window.current_frame.scene_builder.insert(
791 &window.current_frame.z_index_stack,
792 path.scale(scale_factor),
793 );
794 }
795
796 /// Paint an underline into the scene for the current frame at the current z-index.
797 pub fn paint_underline(
798 &mut self,
799 origin: Point<Pixels>,
800 width: Pixels,
801 style: &UnderlineStyle,
802 ) -> Result<()> {
803 let scale_factor = self.scale_factor();
804 let height = if style.wavy {
805 style.thickness * 3.
806 } else {
807 style.thickness
808 };
809 let bounds = Bounds {
810 origin,
811 size: size(width, height),
812 };
813 let content_mask = self.content_mask();
814 let window = &mut *self.window;
815 window.current_frame.scene_builder.insert(
816 &window.current_frame.z_index_stack,
817 Underline {
818 order: 0,
819 bounds: bounds.scale(scale_factor),
820 content_mask: content_mask.scale(scale_factor),
821 thickness: style.thickness.scale(scale_factor),
822 color: style.color.unwrap_or_default(),
823 wavy: style.wavy,
824 },
825 );
826 Ok(())
827 }
828
829 /// Paint a monochrome (non-emoji) glyph into the scene for the current frame at the current z-index.
830 /// The y component of the origin is the baseline of the glyph.
831 pub fn paint_glyph(
832 &mut self,
833 origin: Point<Pixels>,
834 font_id: FontId,
835 glyph_id: GlyphId,
836 font_size: Pixels,
837 color: Hsla,
838 ) -> Result<()> {
839 let scale_factor = self.scale_factor();
840 let glyph_origin = origin.scale(scale_factor);
841 let subpixel_variant = Point {
842 x: (glyph_origin.x.0.fract() * SUBPIXEL_VARIANTS as f32).floor() as u8,
843 y: (glyph_origin.y.0.fract() * SUBPIXEL_VARIANTS as f32).floor() as u8,
844 };
845 let params = RenderGlyphParams {
846 font_id,
847 glyph_id,
848 font_size,
849 subpixel_variant,
850 scale_factor,
851 is_emoji: false,
852 };
853
854 let raster_bounds = self.text_system().raster_bounds(¶ms)?;
855 if !raster_bounds.is_zero() {
856 let tile =
857 self.window
858 .sprite_atlas
859 .get_or_insert_with(¶ms.clone().into(), &mut || {
860 let (size, bytes) = self.text_system().rasterize_glyph(¶ms)?;
861 Ok((size, Cow::Owned(bytes)))
862 })?;
863 let bounds = Bounds {
864 origin: glyph_origin.map(|px| px.floor()) + raster_bounds.origin.map(Into::into),
865 size: tile.bounds.size.map(Into::into),
866 };
867 let content_mask = self.content_mask().scale(scale_factor);
868 let window = &mut *self.window;
869 window.current_frame.scene_builder.insert(
870 &window.current_frame.z_index_stack,
871 MonochromeSprite {
872 order: 0,
873 bounds,
874 content_mask,
875 color,
876 tile,
877 },
878 );
879 }
880 Ok(())
881 }
882
883 /// Paint an emoji glyph into the scene for the current frame at the current z-index.
884 /// The y component of the origin is the baseline of the glyph.
885 pub fn paint_emoji(
886 &mut self,
887 origin: Point<Pixels>,
888 font_id: FontId,
889 glyph_id: GlyphId,
890 font_size: Pixels,
891 ) -> Result<()> {
892 let scale_factor = self.scale_factor();
893 let glyph_origin = origin.scale(scale_factor);
894 let params = RenderGlyphParams {
895 font_id,
896 glyph_id,
897 font_size,
898 // We don't render emojis with subpixel variants.
899 subpixel_variant: Default::default(),
900 scale_factor,
901 is_emoji: true,
902 };
903
904 let raster_bounds = self.text_system().raster_bounds(¶ms)?;
905 if !raster_bounds.is_zero() {
906 let tile =
907 self.window
908 .sprite_atlas
909 .get_or_insert_with(¶ms.clone().into(), &mut || {
910 let (size, bytes) = self.text_system().rasterize_glyph(¶ms)?;
911 Ok((size, Cow::Owned(bytes)))
912 })?;
913 let bounds = Bounds {
914 origin: glyph_origin.map(|px| px.floor()) + raster_bounds.origin.map(Into::into),
915 size: tile.bounds.size.map(Into::into),
916 };
917 let content_mask = self.content_mask().scale(scale_factor);
918 let window = &mut *self.window;
919
920 window.current_frame.scene_builder.insert(
921 &window.current_frame.z_index_stack,
922 PolychromeSprite {
923 order: 0,
924 bounds,
925 corner_radii: Default::default(),
926 content_mask,
927 tile,
928 grayscale: false,
929 },
930 );
931 }
932 Ok(())
933 }
934
935 /// Paint a monochrome SVG into the scene for the current frame at the current stacking context.
936 pub fn paint_svg(
937 &mut self,
938 bounds: Bounds<Pixels>,
939 path: SharedString,
940 color: Hsla,
941 ) -> Result<()> {
942 let scale_factor = self.scale_factor();
943 let bounds = bounds.scale(scale_factor);
944 // Render the SVG at twice the size to get a higher quality result.
945 let params = RenderSvgParams {
946 path,
947 size: bounds
948 .size
949 .map(|pixels| DevicePixels::from((pixels.0 * 2.).ceil() as i32)),
950 };
951
952 let tile =
953 self.window
954 .sprite_atlas
955 .get_or_insert_with(¶ms.clone().into(), &mut || {
956 let bytes = self.svg_renderer.render(¶ms)?;
957 Ok((params.size, Cow::Owned(bytes)))
958 })?;
959 let content_mask = self.content_mask().scale(scale_factor);
960
961 let window = &mut *self.window;
962 window.current_frame.scene_builder.insert(
963 &window.current_frame.z_index_stack,
964 MonochromeSprite {
965 order: 0,
966 bounds,
967 content_mask,
968 color,
969 tile,
970 },
971 );
972
973 Ok(())
974 }
975
976 /// Paint an image into the scene for the current frame at the current z-index.
977 pub fn paint_image(
978 &mut self,
979 bounds: Bounds<Pixels>,
980 corner_radii: Corners<Pixels>,
981 data: Arc<ImageData>,
982 grayscale: bool,
983 ) -> Result<()> {
984 let scale_factor = self.scale_factor();
985 let bounds = bounds.scale(scale_factor);
986 let params = RenderImageParams { image_id: data.id };
987
988 let tile = self
989 .window
990 .sprite_atlas
991 .get_or_insert_with(¶ms.clone().into(), &mut || {
992 Ok((data.size(), Cow::Borrowed(data.as_bytes())))
993 })?;
994 let content_mask = self.content_mask().scale(scale_factor);
995 let corner_radii = corner_radii.scale(scale_factor);
996
997 let window = &mut *self.window;
998 window.current_frame.scene_builder.insert(
999 &window.current_frame.z_index_stack,
1000 PolychromeSprite {
1001 order: 0,
1002 bounds,
1003 content_mask,
1004 corner_radii,
1005 tile,
1006 grayscale,
1007 },
1008 );
1009 Ok(())
1010 }
1011
1012 /// Draw pixels to the display for this window based on the contents of its scene.
1013 pub(crate) fn draw(&mut self) {
1014 let root_view = self.window.root_view.take().unwrap();
1015
1016 self.start_frame();
1017
1018 self.stack(0, |cx| {
1019 let available_space = cx.window.content_size.map(Into::into);
1020 root_view.draw(available_space, cx);
1021 });
1022
1023 if let Some(active_drag) = self.app.active_drag.take() {
1024 self.stack(1, |cx| {
1025 let offset = cx.mouse_position() - active_drag.cursor_offset;
1026 cx.with_element_offset(Some(offset), |cx| {
1027 let available_space =
1028 size(AvailableSpace::MinContent, AvailableSpace::MinContent);
1029 active_drag.view.draw(available_space, cx);
1030 cx.active_drag = Some(active_drag);
1031 });
1032 });
1033 } else if let Some(active_tooltip) = self.app.active_tooltip.take() {
1034 self.stack(1, |cx| {
1035 cx.with_element_offset(Some(active_tooltip.cursor_offset), |cx| {
1036 let available_space =
1037 size(AvailableSpace::MinContent, AvailableSpace::MinContent);
1038 active_tooltip.view.draw(available_space, cx);
1039 });
1040 });
1041 }
1042
1043 self.window.root_view = Some(root_view);
1044 let scene = self.window.current_frame.scene_builder.build();
1045
1046 self.window.platform_window.draw(scene);
1047 let cursor_style = self
1048 .window
1049 .requested_cursor_style
1050 .take()
1051 .unwrap_or(CursorStyle::Arrow);
1052 self.platform.set_cursor_style(cursor_style);
1053
1054 self.window.dirty = false;
1055 }
1056
1057 /// Rotate the current frame and the previous frame, then clear the current frame.
1058 /// We repopulate all state in the current frame during each paint.
1059 fn start_frame(&mut self) {
1060 self.text_system().start_frame();
1061
1062 let window = &mut *self.window;
1063 mem::swap(&mut window.previous_frame, &mut window.current_frame);
1064 let frame = &mut window.current_frame;
1065 frame.element_states.clear();
1066 frame.key_matchers.clear();
1067 frame.mouse_listeners.values_mut().for_each(Vec::clear);
1068 frame.focus_listeners.clear();
1069 frame.key_dispatch_stack.clear();
1070 frame.focus_parents_by_child.clear();
1071 frame.freeze_key_dispatch_stack = false;
1072 }
1073
1074 /// Dispatch a mouse or keyboard event on the window.
1075 pub fn dispatch_event(&mut self, event: InputEvent) -> bool {
1076 // Handlers may set this to false by calling `stop_propagation`
1077 self.app.propagate_event = true;
1078 self.window.default_prevented = false;
1079
1080 let event = match event {
1081 // Track the mouse position with our own state, since accessing the platform
1082 // API for the mouse position can only occur on the main thread.
1083 InputEvent::MouseMove(mouse_move) => {
1084 self.window.mouse_position = mouse_move.position;
1085 InputEvent::MouseMove(mouse_move)
1086 }
1087 // Translate dragging and dropping of external files from the operating system
1088 // to internal drag and drop events.
1089 InputEvent::FileDrop(file_drop) => match file_drop {
1090 FileDropEvent::Entered { position, files } => {
1091 self.window.mouse_position = position;
1092 if self.active_drag.is_none() {
1093 self.active_drag = Some(AnyDrag {
1094 view: self.build_view(|_| files).into(),
1095 cursor_offset: position,
1096 });
1097 }
1098 InputEvent::MouseDown(MouseDownEvent {
1099 position,
1100 button: MouseButton::Left,
1101 click_count: 1,
1102 modifiers: Modifiers::default(),
1103 })
1104 }
1105 FileDropEvent::Pending { position } => {
1106 self.window.mouse_position = position;
1107 InputEvent::MouseMove(MouseMoveEvent {
1108 position,
1109 pressed_button: Some(MouseButton::Left),
1110 modifiers: Modifiers::default(),
1111 })
1112 }
1113 FileDropEvent::Submit { position } => {
1114 self.window.mouse_position = position;
1115 InputEvent::MouseUp(MouseUpEvent {
1116 button: MouseButton::Left,
1117 position,
1118 modifiers: Modifiers::default(),
1119 click_count: 1,
1120 })
1121 }
1122 FileDropEvent::Exited => InputEvent::MouseUp(MouseUpEvent {
1123 button: MouseButton::Left,
1124 position: Point::default(),
1125 modifiers: Modifiers::default(),
1126 click_count: 1,
1127 }),
1128 },
1129 _ => event,
1130 };
1131
1132 if let Some(any_mouse_event) = event.mouse_event() {
1133 if let Some(mut handlers) = self
1134 .window
1135 .current_frame
1136 .mouse_listeners
1137 .remove(&any_mouse_event.type_id())
1138 {
1139 // Because handlers may add other handlers, we sort every time.
1140 handlers.sort_by(|(a, _), (b, _)| a.cmp(b));
1141
1142 // Capture phase, events bubble from back to front. Handlers for this phase are used for
1143 // special purposes, such as detecting events outside of a given Bounds.
1144 for (_, handler) in &mut handlers {
1145 handler(any_mouse_event, DispatchPhase::Capture, self);
1146 if !self.app.propagate_event {
1147 break;
1148 }
1149 }
1150
1151 // Bubble phase, where most normal handlers do their work.
1152 if self.app.propagate_event {
1153 for (_, handler) in handlers.iter_mut().rev() {
1154 handler(any_mouse_event, DispatchPhase::Bubble, self);
1155 if !self.app.propagate_event {
1156 break;
1157 }
1158 }
1159 }
1160
1161 if self.app.propagate_event
1162 && any_mouse_event.downcast_ref::<MouseUpEvent>().is_some()
1163 {
1164 self.active_drag = None;
1165 }
1166
1167 // Just in case any handlers added new handlers, which is weird, but possible.
1168 handlers.extend(
1169 self.window
1170 .current_frame
1171 .mouse_listeners
1172 .get_mut(&any_mouse_event.type_id())
1173 .into_iter()
1174 .flat_map(|handlers| handlers.drain(..)),
1175 );
1176 self.window
1177 .current_frame
1178 .mouse_listeners
1179 .insert(any_mouse_event.type_id(), handlers);
1180 }
1181 } else if let Some(any_key_event) = event.keyboard_event() {
1182 let key_dispatch_stack = mem::take(&mut self.window.current_frame.key_dispatch_stack);
1183 let key_event_type = any_key_event.type_id();
1184 let mut context_stack = SmallVec::<[&DispatchContext; 16]>::new();
1185
1186 for (ix, frame) in key_dispatch_stack.iter().enumerate() {
1187 match frame {
1188 KeyDispatchStackFrame::Listener {
1189 event_type,
1190 listener,
1191 } => {
1192 if key_event_type == *event_type {
1193 if let Some(action) = listener(
1194 any_key_event,
1195 &context_stack,
1196 DispatchPhase::Capture,
1197 self,
1198 ) {
1199 self.dispatch_action(action, &key_dispatch_stack[..ix]);
1200 }
1201 if !self.app.propagate_event {
1202 break;
1203 }
1204 }
1205 }
1206 KeyDispatchStackFrame::Context(context) => {
1207 context_stack.push(&context);
1208 }
1209 }
1210 }
1211
1212 if self.app.propagate_event {
1213 for (ix, frame) in key_dispatch_stack.iter().enumerate().rev() {
1214 match frame {
1215 KeyDispatchStackFrame::Listener {
1216 event_type,
1217 listener,
1218 } => {
1219 if key_event_type == *event_type {
1220 if let Some(action) = listener(
1221 any_key_event,
1222 &context_stack,
1223 DispatchPhase::Bubble,
1224 self,
1225 ) {
1226 self.dispatch_action(action, &key_dispatch_stack[..ix]);
1227 }
1228
1229 if !self.app.propagate_event {
1230 break;
1231 }
1232 }
1233 }
1234 KeyDispatchStackFrame::Context(_) => {
1235 context_stack.pop();
1236 }
1237 }
1238 }
1239 }
1240
1241 drop(context_stack);
1242 self.window.current_frame.key_dispatch_stack = key_dispatch_stack;
1243 }
1244
1245 !self.app.propagate_event
1246 }
1247
1248 /// Attempt to map a keystroke to an action based on the keymap.
1249 pub fn match_keystroke(
1250 &mut self,
1251 element_id: &GlobalElementId,
1252 keystroke: &Keystroke,
1253 context_stack: &[&DispatchContext],
1254 ) -> KeyMatch {
1255 let key_match = self
1256 .window
1257 .current_frame
1258 .key_matchers
1259 .get_mut(element_id)
1260 .unwrap()
1261 .match_keystroke(keystroke, context_stack);
1262
1263 if key_match.is_some() {
1264 for matcher in self.window.current_frame.key_matchers.values_mut() {
1265 matcher.clear_pending();
1266 }
1267 }
1268
1269 key_match
1270 }
1271
1272 /// Register the given handler to be invoked whenever the global of the given type
1273 /// is updated.
1274 pub fn observe_global<G: 'static>(
1275 &mut self,
1276 f: impl Fn(&mut WindowContext<'_>) + 'static,
1277 ) -> Subscription {
1278 let window_handle = self.window.handle;
1279 self.global_observers.insert(
1280 TypeId::of::<G>(),
1281 Box::new(move |cx| window_handle.update(cx, |_, cx| f(cx)).is_ok()),
1282 )
1283 }
1284
1285 pub fn activate_window(&self) {
1286 self.window.platform_window.activate();
1287 }
1288
1289 pub fn prompt(
1290 &self,
1291 level: PromptLevel,
1292 msg: &str,
1293 answers: &[&str],
1294 ) -> oneshot::Receiver<usize> {
1295 self.window.platform_window.prompt(level, msg, answers)
1296 }
1297
1298 fn dispatch_action(
1299 &mut self,
1300 action: Box<dyn Action>,
1301 dispatch_stack: &[KeyDispatchStackFrame],
1302 ) {
1303 let action_type = action.as_any().type_id();
1304
1305 if let Some(mut global_listeners) = self.app.global_action_listeners.remove(&action_type) {
1306 for listener in &global_listeners {
1307 listener(action.as_ref(), DispatchPhase::Capture, self);
1308 if !self.app.propagate_event {
1309 break;
1310 }
1311 }
1312 global_listeners.extend(
1313 self.global_action_listeners
1314 .remove(&action_type)
1315 .unwrap_or_default(),
1316 );
1317 self.global_action_listeners
1318 .insert(action_type, global_listeners);
1319 }
1320
1321 if self.app.propagate_event {
1322 for stack_frame in dispatch_stack {
1323 if let KeyDispatchStackFrame::Listener {
1324 event_type,
1325 listener,
1326 } = stack_frame
1327 {
1328 if action_type == *event_type {
1329 listener(action.as_any(), &[], DispatchPhase::Capture, self);
1330 if !self.app.propagate_event {
1331 break;
1332 }
1333 }
1334 }
1335 }
1336 }
1337
1338 if self.app.propagate_event {
1339 for stack_frame in dispatch_stack.iter().rev() {
1340 if let KeyDispatchStackFrame::Listener {
1341 event_type,
1342 listener,
1343 } = stack_frame
1344 {
1345 if action_type == *event_type {
1346 self.app.propagate_event = false;
1347 listener(action.as_any(), &[], DispatchPhase::Bubble, self);
1348 if !self.app.propagate_event {
1349 break;
1350 }
1351 }
1352 }
1353 }
1354 }
1355
1356 if self.app.propagate_event {
1357 if let Some(mut global_listeners) =
1358 self.app.global_action_listeners.remove(&action_type)
1359 {
1360 for listener in global_listeners.iter().rev() {
1361 self.app.propagate_event = false;
1362 listener(action.as_ref(), DispatchPhase::Bubble, self);
1363 if !self.app.propagate_event {
1364 break;
1365 }
1366 }
1367 global_listeners.extend(
1368 self.global_action_listeners
1369 .remove(&action_type)
1370 .unwrap_or_default(),
1371 );
1372 self.global_action_listeners
1373 .insert(action_type, global_listeners);
1374 }
1375 }
1376 }
1377}
1378
1379impl Context for WindowContext<'_> {
1380 type Result<T> = T;
1381
1382 fn build_model<T>(
1383 &mut self,
1384 build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
1385 ) -> Model<T>
1386 where
1387 T: 'static,
1388 {
1389 let slot = self.app.entities.reserve();
1390 let model = build_model(&mut ModelContext::new(&mut *self.app, slot.downgrade()));
1391 self.entities.insert(slot, model)
1392 }
1393
1394 fn update_model<T: 'static, R>(
1395 &mut self,
1396 model: &Model<T>,
1397 update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
1398 ) -> R {
1399 let mut entity = self.entities.lease(model);
1400 let result = update(
1401 &mut *entity,
1402 &mut ModelContext::new(&mut *self.app, model.downgrade()),
1403 );
1404 self.entities.end_lease(entity);
1405 result
1406 }
1407
1408 fn update_window<T, F>(&mut self, window: AnyWindowHandle, update: F) -> Result<T>
1409 where
1410 F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
1411 {
1412 if window == self.window.handle {
1413 let root_view = self.window.root_view.clone().unwrap();
1414 Ok(update(root_view, self))
1415 } else {
1416 window.update(self.app, update)
1417 }
1418 }
1419
1420 fn read_model<T, R>(
1421 &self,
1422 handle: &Model<T>,
1423 read: impl FnOnce(&T, &AppContext) -> R,
1424 ) -> Self::Result<R>
1425 where
1426 T: 'static,
1427 {
1428 let entity = self.entities.read(handle);
1429 read(&*entity, &*self.app)
1430 }
1431
1432 fn read_window<R>(
1433 &self,
1434 window: &AnyWindowHandle,
1435 read: impl FnOnce(AnyView, &AppContext) -> R,
1436 ) -> Result<R> {
1437 if window == &self.window.handle {
1438 let root_view = self.window.root_view.clone().unwrap();
1439 Ok(read(root_view, self))
1440 } else {
1441 window.read(self.app, read)
1442 }
1443 }
1444}
1445
1446impl VisualContext for WindowContext<'_> {
1447 fn build_view<V>(
1448 &mut self,
1449 build_view_state: impl FnOnce(&mut ViewContext<'_, V>) -> V,
1450 ) -> Self::Result<View<V>>
1451 where
1452 V: 'static + Render,
1453 {
1454 let slot = self.app.entities.reserve();
1455 let view = View {
1456 model: slot.clone(),
1457 };
1458 let mut cx = ViewContext::new(&mut *self.app, &mut *self.window, &view);
1459 let entity = build_view_state(&mut cx);
1460 cx.entities.insert(slot, entity);
1461
1462 cx.new_view_observers
1463 .clone()
1464 .retain(&TypeId::of::<V>(), |observer| {
1465 let any_view = AnyView::from(view.clone());
1466 (observer)(any_view, self);
1467 true
1468 });
1469
1470 view
1471 }
1472
1473 /// Update the given view. Prefer calling `View::update` instead, which calls this method.
1474 fn update_view<T: 'static, R>(
1475 &mut self,
1476 view: &View<T>,
1477 update: impl FnOnce(&mut T, &mut ViewContext<'_, T>) -> R,
1478 ) -> Self::Result<R> {
1479 let mut lease = self.app.entities.lease(&view.model);
1480 let mut cx = ViewContext::new(&mut *self.app, &mut *self.window, &view);
1481 let result = update(&mut *lease, &mut cx);
1482 cx.app.entities.end_lease(lease);
1483 result
1484 }
1485
1486 fn replace_root_view<V>(
1487 &mut self,
1488 build_view: impl FnOnce(&mut ViewContext<'_, V>) -> V,
1489 ) -> Self::Result<View<V>>
1490 where
1491 V: Render,
1492 {
1493 let slot = self.app.entities.reserve();
1494 let view = View {
1495 model: slot.clone(),
1496 };
1497 let mut cx = ViewContext::new(&mut *self.app, &mut *self.window, &view);
1498 let entity = build_view(&mut cx);
1499 self.entities.insert(slot, entity);
1500 self.window.root_view = Some(view.clone().into());
1501 view
1502 }
1503}
1504
1505impl<'a> std::ops::Deref for WindowContext<'a> {
1506 type Target = AppContext;
1507
1508 fn deref(&self) -> &Self::Target {
1509 &self.app
1510 }
1511}
1512
1513impl<'a> std::ops::DerefMut for WindowContext<'a> {
1514 fn deref_mut(&mut self) -> &mut Self::Target {
1515 &mut self.app
1516 }
1517}
1518
1519impl<'a> Borrow<AppContext> for WindowContext<'a> {
1520 fn borrow(&self) -> &AppContext {
1521 &self.app
1522 }
1523}
1524
1525impl<'a> BorrowMut<AppContext> for WindowContext<'a> {
1526 fn borrow_mut(&mut self) -> &mut AppContext {
1527 &mut self.app
1528 }
1529}
1530
1531pub trait BorrowWindow: BorrowMut<Window> + BorrowMut<AppContext> {
1532 fn app_mut(&mut self) -> &mut AppContext {
1533 self.borrow_mut()
1534 }
1535
1536 fn window(&self) -> &Window {
1537 self.borrow()
1538 }
1539
1540 fn window_mut(&mut self) -> &mut Window {
1541 self.borrow_mut()
1542 }
1543
1544 /// Pushes the given element id onto the global stack and invokes the given closure
1545 /// with a `GlobalElementId`, which disambiguates the given id in the context of its ancestor
1546 /// ids. Because elements are discarded and recreated on each frame, the `GlobalElementId` is
1547 /// used to associate state with identified elements across separate frames.
1548 fn with_element_id<R>(
1549 &mut self,
1550 id: impl Into<ElementId>,
1551 f: impl FnOnce(GlobalElementId, &mut Self) -> R,
1552 ) -> R {
1553 let keymap = self.app_mut().keymap.clone();
1554 let window = self.window_mut();
1555 window.element_id_stack.push(id.into());
1556 let global_id = window.element_id_stack.clone();
1557
1558 if window.current_frame.key_matchers.get(&global_id).is_none() {
1559 window.current_frame.key_matchers.insert(
1560 global_id.clone(),
1561 window
1562 .previous_frame
1563 .key_matchers
1564 .remove(&global_id)
1565 .unwrap_or_else(|| KeyMatcher::new(keymap)),
1566 );
1567 }
1568
1569 let result = f(global_id, self);
1570 let window: &mut Window = self.borrow_mut();
1571 window.element_id_stack.pop();
1572 result
1573 }
1574
1575 /// Invoke the given function with the given content mask after intersecting it
1576 /// with the current mask.
1577 fn with_content_mask<R>(
1578 &mut self,
1579 mask: ContentMask<Pixels>,
1580 f: impl FnOnce(&mut Self) -> R,
1581 ) -> R {
1582 let mask = mask.intersect(&self.content_mask());
1583 self.window_mut()
1584 .current_frame
1585 .content_mask_stack
1586 .push(mask);
1587 let result = f(self);
1588 self.window_mut().current_frame.content_mask_stack.pop();
1589 result
1590 }
1591
1592 /// Update the global element offset based on the given offset. This is used to implement
1593 /// scrolling and position drag handles.
1594 fn with_element_offset<R>(
1595 &mut self,
1596 offset: Option<Point<Pixels>>,
1597 f: impl FnOnce(&mut Self) -> R,
1598 ) -> R {
1599 let Some(offset) = offset else {
1600 return f(self);
1601 };
1602
1603 let offset = self.element_offset() + offset;
1604 self.window_mut()
1605 .current_frame
1606 .element_offset_stack
1607 .push(offset);
1608 let result = f(self);
1609 self.window_mut().current_frame.element_offset_stack.pop();
1610 result
1611 }
1612
1613 /// Obtain the current element offset.
1614 fn element_offset(&self) -> Point<Pixels> {
1615 self.window()
1616 .current_frame
1617 .element_offset_stack
1618 .last()
1619 .copied()
1620 .unwrap_or_default()
1621 }
1622
1623 /// Update or intialize state for an element with the given id that lives across multiple
1624 /// frames. If an element with this id existed in the previous frame, its state will be passed
1625 /// to the given closure. The state returned by the closure will be stored so it can be referenced
1626 /// when drawing the next frame.
1627 fn with_element_state<S, R>(
1628 &mut self,
1629 id: ElementId,
1630 f: impl FnOnce(Option<S>, &mut Self) -> (R, S),
1631 ) -> R
1632 where
1633 S: 'static,
1634 {
1635 self.with_element_id(id, |global_id, cx| {
1636 if let Some(any) = cx
1637 .window_mut()
1638 .current_frame
1639 .element_states
1640 .remove(&global_id)
1641 .or_else(|| {
1642 cx.window_mut()
1643 .previous_frame
1644 .element_states
1645 .remove(&global_id)
1646 })
1647 {
1648 // Using the extra inner option to avoid needing to reallocate a new box.
1649 let mut state_box = any
1650 .downcast::<Option<S>>()
1651 .expect("invalid element state type for id");
1652 let state = state_box
1653 .take()
1654 .expect("element state is already on the stack");
1655 let (result, state) = f(Some(state), cx);
1656 state_box.replace(state);
1657 cx.window_mut()
1658 .current_frame
1659 .element_states
1660 .insert(global_id, state_box);
1661 result
1662 } else {
1663 let (result, state) = f(None, cx);
1664 cx.window_mut()
1665 .current_frame
1666 .element_states
1667 .insert(global_id, Box::new(Some(state)));
1668 result
1669 }
1670 })
1671 }
1672
1673 /// Like `with_element_state`, but for situations where the element_id is optional. If the
1674 /// id is `None`, no state will be retrieved or stored.
1675 fn with_optional_element_state<S, R>(
1676 &mut self,
1677 element_id: Option<ElementId>,
1678 f: impl FnOnce(Option<S>, &mut Self) -> (R, S),
1679 ) -> R
1680 where
1681 S: 'static,
1682 {
1683 if let Some(element_id) = element_id {
1684 self.with_element_state(element_id, f)
1685 } else {
1686 f(None, self).0
1687 }
1688 }
1689
1690 /// Obtain the current content mask.
1691 fn content_mask(&self) -> ContentMask<Pixels> {
1692 self.window()
1693 .current_frame
1694 .content_mask_stack
1695 .last()
1696 .cloned()
1697 .unwrap_or_else(|| ContentMask {
1698 bounds: Bounds {
1699 origin: Point::default(),
1700 size: self.window().content_size,
1701 },
1702 })
1703 }
1704
1705 /// The size of an em for the base font of the application. Adjusting this value allows the
1706 /// UI to scale, just like zooming a web page.
1707 fn rem_size(&self) -> Pixels {
1708 self.window().rem_size
1709 }
1710}
1711
1712impl Borrow<Window> for WindowContext<'_> {
1713 fn borrow(&self) -> &Window {
1714 &self.window
1715 }
1716}
1717
1718impl BorrowMut<Window> for WindowContext<'_> {
1719 fn borrow_mut(&mut self) -> &mut Window {
1720 &mut self.window
1721 }
1722}
1723
1724impl<T> BorrowWindow for T where T: BorrowMut<AppContext> + BorrowMut<Window> {}
1725
1726pub struct ViewContext<'a, V> {
1727 window_cx: WindowContext<'a>,
1728 view: &'a View<V>,
1729}
1730
1731impl<V> Borrow<AppContext> for ViewContext<'_, V> {
1732 fn borrow(&self) -> &AppContext {
1733 &*self.window_cx.app
1734 }
1735}
1736
1737impl<V> BorrowMut<AppContext> for ViewContext<'_, V> {
1738 fn borrow_mut(&mut self) -> &mut AppContext {
1739 &mut *self.window_cx.app
1740 }
1741}
1742
1743impl<V> Borrow<Window> for ViewContext<'_, V> {
1744 fn borrow(&self) -> &Window {
1745 &*self.window_cx.window
1746 }
1747}
1748
1749impl<V> BorrowMut<Window> for ViewContext<'_, V> {
1750 fn borrow_mut(&mut self) -> &mut Window {
1751 &mut *self.window_cx.window
1752 }
1753}
1754
1755impl<'a, V: 'static> ViewContext<'a, V> {
1756 pub(crate) fn new(app: &'a mut AppContext, window: &'a mut Window, view: &'a View<V>) -> Self {
1757 Self {
1758 window_cx: WindowContext::new(app, window),
1759 view,
1760 }
1761 }
1762
1763 pub fn view(&self) -> &View<V> {
1764 self.view
1765 }
1766
1767 pub fn model(&self) -> Model<V> {
1768 self.view.model.clone()
1769 }
1770
1771 /// Access the underlying window context.
1772 pub fn window_context(&mut self) -> &mut WindowContext<'a> {
1773 &mut self.window_cx
1774 }
1775
1776 pub fn with_z_index<R>(&mut self, z_index: u32, f: impl FnOnce(&mut Self) -> R) -> R {
1777 self.window.current_frame.z_index_stack.push(z_index);
1778 let result = f(self);
1779 self.window.current_frame.z_index_stack.pop();
1780 result
1781 }
1782
1783 pub fn on_next_frame(&mut self, f: impl FnOnce(&mut V, &mut ViewContext<V>) + 'static)
1784 where
1785 V: 'static,
1786 {
1787 let view = self.view().clone();
1788 self.window_cx.on_next_frame(move |cx| view.update(cx, f));
1789 }
1790
1791 /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
1792 /// that are currently on the stack to be returned to the app.
1793 pub fn defer(&mut self, f: impl FnOnce(&mut V, &mut ViewContext<V>) + 'static) {
1794 let view = self.view().downgrade();
1795 self.window_cx.defer(move |cx| {
1796 view.update(cx, f).ok();
1797 });
1798 }
1799
1800 pub fn observe<V2, E>(
1801 &mut self,
1802 entity: &E,
1803 mut on_notify: impl FnMut(&mut V, E, &mut ViewContext<'_, V>) + 'static,
1804 ) -> Subscription
1805 where
1806 V2: 'static,
1807 V: 'static,
1808 E: Entity<V2>,
1809 {
1810 let view = self.view().downgrade();
1811 let entity_id = entity.entity_id();
1812 let entity = entity.downgrade();
1813 let window_handle = self.window.handle;
1814 self.app.observers.insert(
1815 entity_id,
1816 Box::new(move |cx| {
1817 window_handle
1818 .update(cx, |_, cx| {
1819 if let Some(handle) = E::upgrade_from(&entity) {
1820 view.update(cx, |this, cx| on_notify(this, handle, cx))
1821 .is_ok()
1822 } else {
1823 false
1824 }
1825 })
1826 .unwrap_or(false)
1827 }),
1828 )
1829 }
1830
1831 pub fn subscribe<V2, E, Evt>(
1832 &mut self,
1833 entity: &E,
1834 mut on_event: impl FnMut(&mut V, E, &Evt, &mut ViewContext<'_, V>) + 'static,
1835 ) -> Subscription
1836 where
1837 V2: EventEmitter<Evt>,
1838 E: Entity<V2>,
1839 Evt: 'static,
1840 {
1841 let view = self.view().downgrade();
1842 let entity_id = entity.entity_id();
1843 let handle = entity.downgrade();
1844 let window_handle = self.window.handle;
1845 self.app.event_listeners.insert(
1846 entity_id,
1847 (
1848 TypeId::of::<Evt>(),
1849 Box::new(move |event, cx| {
1850 window_handle
1851 .update(cx, |_, cx| {
1852 if let Some(handle) = E::upgrade_from(&handle) {
1853 let event = event.downcast_ref().expect("invalid event type");
1854 view.update(cx, |this, cx| on_event(this, handle, event, cx))
1855 .is_ok()
1856 } else {
1857 false
1858 }
1859 })
1860 .unwrap_or(false)
1861 }),
1862 ),
1863 )
1864 }
1865
1866 pub fn on_release(
1867 &mut self,
1868 on_release: impl FnOnce(&mut V, &mut WindowContext) + 'static,
1869 ) -> Subscription {
1870 let window_handle = self.window.handle;
1871 self.app.release_listeners.insert(
1872 self.view.model.entity_id,
1873 Box::new(move |this, cx| {
1874 let this = this.downcast_mut().expect("invalid entity type");
1875 let _ = window_handle.update(cx, |_, cx| on_release(this, cx));
1876 }),
1877 )
1878 }
1879
1880 pub fn observe_release<V2, E>(
1881 &mut self,
1882 entity: &E,
1883 mut on_release: impl FnMut(&mut V, &mut V2, &mut ViewContext<'_, V>) + 'static,
1884 ) -> Subscription
1885 where
1886 V: 'static,
1887 V2: 'static,
1888 E: Entity<V2>,
1889 {
1890 let view = self.view().downgrade();
1891 let entity_id = entity.entity_id();
1892 let window_handle = self.window.handle;
1893 self.app.release_listeners.insert(
1894 entity_id,
1895 Box::new(move |entity, cx| {
1896 let entity = entity.downcast_mut().expect("invalid entity type");
1897 let _ = window_handle.update(cx, |_, cx| {
1898 view.update(cx, |this, cx| on_release(this, entity, cx))
1899 });
1900 }),
1901 )
1902 }
1903
1904 pub fn notify(&mut self) {
1905 self.window_cx.notify();
1906 self.window_cx.app.push_effect(Effect::Notify {
1907 emitter: self.view.model.entity_id,
1908 });
1909 }
1910
1911 pub fn observe_window_bounds(
1912 &mut self,
1913 mut callback: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
1914 ) -> Subscription {
1915 let view = self.view.downgrade();
1916 self.window.bounds_observers.insert(
1917 (),
1918 Box::new(move |cx| view.update(cx, |view, cx| callback(view, cx)).is_ok()),
1919 )
1920 }
1921
1922 pub fn observe_window_activation(
1923 &mut self,
1924 mut callback: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
1925 ) -> Subscription {
1926 let view = self.view.downgrade();
1927 self.window.activation_observers.insert(
1928 (),
1929 Box::new(move |cx| view.update(cx, |view, cx| callback(view, cx)).is_ok()),
1930 )
1931 }
1932
1933 /// Register a listener to be called when the given focus handle receives focus.
1934 /// Unlike [on_focus_changed], returns a subscription and persists until the subscription
1935 /// is dropped.
1936 pub fn on_focus(
1937 &mut self,
1938 handle: &FocusHandle,
1939 mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
1940 ) -> Subscription {
1941 let view = self.view.downgrade();
1942 let focus_id = handle.id;
1943 self.window.focus_listeners.insert(
1944 (),
1945 Box::new(move |event, cx| {
1946 view.update(cx, |view, cx| {
1947 if event.focused.as_ref().map(|focused| focused.id) == Some(focus_id) {
1948 listener(view, cx)
1949 }
1950 })
1951 .is_ok()
1952 }),
1953 )
1954 }
1955
1956 /// Register a listener to be called when the given focus handle or one of its descendants receives focus.
1957 /// Unlike [on_focus_changed], returns a subscription and persists until the subscription
1958 /// is dropped.
1959 pub fn on_focus_in(
1960 &mut self,
1961 handle: &FocusHandle,
1962 mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
1963 ) -> Subscription {
1964 let view = self.view.downgrade();
1965 let focus_id = handle.id;
1966 self.window.focus_listeners.insert(
1967 (),
1968 Box::new(move |event, cx| {
1969 view.update(cx, |view, cx| {
1970 if event
1971 .focused
1972 .as_ref()
1973 .map_or(false, |focused| focus_id.contains(focused.id, cx))
1974 {
1975 listener(view, cx)
1976 }
1977 })
1978 .is_ok()
1979 }),
1980 )
1981 }
1982
1983 /// Register a listener to be called when the given focus handle loses focus.
1984 /// Unlike [on_focus_changed], returns a subscription and persists until the subscription
1985 /// is dropped.
1986 pub fn on_blur(
1987 &mut self,
1988 handle: &FocusHandle,
1989 mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
1990 ) -> Subscription {
1991 let view = self.view.downgrade();
1992 let focus_id = handle.id;
1993 self.window.focus_listeners.insert(
1994 (),
1995 Box::new(move |event, cx| {
1996 view.update(cx, |view, cx| {
1997 if event.blurred.as_ref().map(|blurred| blurred.id) == Some(focus_id) {
1998 listener(view, cx)
1999 }
2000 })
2001 .is_ok()
2002 }),
2003 )
2004 }
2005
2006 /// Register a listener to be called when the given focus handle or one of its descendants loses focus.
2007 /// Unlike [on_focus_changed], returns a subscription and persists until the subscription
2008 /// is dropped.
2009 pub fn on_focus_out(
2010 &mut self,
2011 handle: &FocusHandle,
2012 mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2013 ) -> Subscription {
2014 let view = self.view.downgrade();
2015 let focus_id = handle.id;
2016 self.window.focus_listeners.insert(
2017 (),
2018 Box::new(move |event, cx| {
2019 view.update(cx, |view, cx| {
2020 if event
2021 .blurred
2022 .as_ref()
2023 .map_or(false, |blurred| focus_id.contains(blurred.id, cx))
2024 {
2025 listener(view, cx)
2026 }
2027 })
2028 .is_ok()
2029 }),
2030 )
2031 }
2032
2033 /// Register a focus listener for the current frame only. It will be cleared
2034 /// on the next frame render. You should use this method only from within elements,
2035 /// and we may want to enforce that better via a different context type.
2036 // todo!() Move this to `FrameContext` to emphasize its individuality?
2037 pub fn on_focus_changed(
2038 &mut self,
2039 listener: impl Fn(&mut V, &FocusEvent, &mut ViewContext<V>) + 'static,
2040 ) {
2041 let handle = self.view().downgrade();
2042 self.window
2043 .current_frame
2044 .focus_listeners
2045 .push(Box::new(move |event, cx| {
2046 handle
2047 .update(cx, |view, cx| listener(view, event, cx))
2048 .log_err();
2049 }));
2050 }
2051
2052 pub fn with_key_listeners<R>(
2053 &mut self,
2054 key_listeners: impl IntoIterator<Item = (TypeId, KeyListener<V>)>,
2055 f: impl FnOnce(&mut Self) -> R,
2056 ) -> R {
2057 let old_stack_len = self.window.current_frame.key_dispatch_stack.len();
2058 if !self.window.current_frame.freeze_key_dispatch_stack {
2059 for (event_type, listener) in key_listeners {
2060 let handle = self.view().downgrade();
2061 let listener = Box::new(
2062 move |event: &dyn Any,
2063 context_stack: &[&DispatchContext],
2064 phase: DispatchPhase,
2065 cx: &mut WindowContext<'_>| {
2066 handle
2067 .update(cx, |view, cx| {
2068 listener(view, event, context_stack, phase, cx)
2069 })
2070 .log_err()
2071 .flatten()
2072 },
2073 );
2074 self.window.current_frame.key_dispatch_stack.push(
2075 KeyDispatchStackFrame::Listener {
2076 event_type,
2077 listener,
2078 },
2079 );
2080 }
2081 }
2082
2083 let result = f(self);
2084
2085 if !self.window.current_frame.freeze_key_dispatch_stack {
2086 self.window
2087 .current_frame
2088 .key_dispatch_stack
2089 .truncate(old_stack_len);
2090 }
2091
2092 result
2093 }
2094
2095 pub fn with_key_dispatch_context<R>(
2096 &mut self,
2097 context: DispatchContext,
2098 f: impl FnOnce(&mut Self) -> R,
2099 ) -> R {
2100 if context.is_empty() {
2101 return f(self);
2102 }
2103
2104 if !self.window.current_frame.freeze_key_dispatch_stack {
2105 self.window
2106 .current_frame
2107 .key_dispatch_stack
2108 .push(KeyDispatchStackFrame::Context(context));
2109 }
2110
2111 let result = f(self);
2112
2113 if !self.window.previous_frame.freeze_key_dispatch_stack {
2114 self.window.previous_frame.key_dispatch_stack.pop();
2115 }
2116
2117 result
2118 }
2119
2120 pub fn with_focus<R>(
2121 &mut self,
2122 focus_handle: FocusHandle,
2123 f: impl FnOnce(&mut Self) -> R,
2124 ) -> R {
2125 if let Some(parent_focus_id) = self.window.current_frame.focus_stack.last().copied() {
2126 self.window
2127 .current_frame
2128 .focus_parents_by_child
2129 .insert(focus_handle.id, parent_focus_id);
2130 }
2131 self.window.current_frame.focus_stack.push(focus_handle.id);
2132
2133 if Some(focus_handle.id) == self.window.focus {
2134 self.window.current_frame.freeze_key_dispatch_stack = true;
2135 }
2136
2137 let result = f(self);
2138
2139 self.window.current_frame.focus_stack.pop();
2140 result
2141 }
2142
2143 pub fn spawn<Fut, R>(
2144 &mut self,
2145 f: impl FnOnce(WeakView<V>, AsyncWindowContext) -> Fut,
2146 ) -> Task<R>
2147 where
2148 R: 'static,
2149 Fut: Future<Output = R> + 'static,
2150 {
2151 let view = self.view().downgrade();
2152 self.window_cx.spawn(|cx| f(view, cx))
2153 }
2154
2155 pub fn update_global<G, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R
2156 where
2157 G: 'static,
2158 {
2159 let mut global = self.app.lease_global::<G>();
2160 let result = f(&mut global, self);
2161 self.app.end_global_lease(global);
2162 result
2163 }
2164
2165 pub fn observe_global<G: 'static>(
2166 &mut self,
2167 f: impl Fn(&mut V, &mut ViewContext<'_, V>) + 'static,
2168 ) -> Subscription {
2169 let window_handle = self.window.handle;
2170 let view = self.view().downgrade();
2171 self.global_observers.insert(
2172 TypeId::of::<G>(),
2173 Box::new(move |cx| {
2174 window_handle
2175 .update(cx, |_, cx| view.update(cx, |view, cx| f(view, cx)).is_ok())
2176 .unwrap_or(false)
2177 }),
2178 )
2179 }
2180
2181 pub fn on_mouse_event<Event: 'static>(
2182 &mut self,
2183 handler: impl Fn(&mut V, &Event, DispatchPhase, &mut ViewContext<V>) + 'static,
2184 ) {
2185 let handle = self.view().clone();
2186 self.window_cx.on_mouse_event(move |event, phase, cx| {
2187 handle.update(cx, |view, cx| {
2188 handler(view, event, phase, cx);
2189 })
2190 });
2191 }
2192
2193 /// Set an input handler, such as [ElementInputHandler], which interfaces with the
2194 /// platform to receive textual input with proper integration with concerns such
2195 /// as IME interactions.
2196 pub fn handle_input(
2197 &mut self,
2198 focus_handle: &FocusHandle,
2199 input_handler: impl PlatformInputHandler,
2200 ) {
2201 if focus_handle.is_focused(self) {
2202 self.window
2203 .platform_window
2204 .set_input_handler(Box::new(input_handler));
2205 }
2206 }
2207}
2208
2209impl<V> ViewContext<'_, V> {
2210 pub fn emit<Evt>(&mut self, event: Evt)
2211 where
2212 Evt: 'static,
2213 V: EventEmitter<Evt>,
2214 {
2215 let emitter = self.view.model.entity_id;
2216 self.app.push_effect(Effect::Emit {
2217 emitter,
2218 event_type: TypeId::of::<Evt>(),
2219 event: Box::new(event),
2220 });
2221 }
2222}
2223
2224impl<V> Context for ViewContext<'_, V> {
2225 type Result<U> = U;
2226
2227 fn build_model<T: 'static>(
2228 &mut self,
2229 build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
2230 ) -> Model<T> {
2231 self.window_cx.build_model(build_model)
2232 }
2233
2234 fn update_model<T: 'static, R>(
2235 &mut self,
2236 model: &Model<T>,
2237 update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
2238 ) -> R {
2239 self.window_cx.update_model(model, update)
2240 }
2241
2242 fn update_window<T, F>(&mut self, window: AnyWindowHandle, update: F) -> Result<T>
2243 where
2244 F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
2245 {
2246 self.window_cx.update_window(window, update)
2247 }
2248
2249 fn read_model<T, R>(
2250 &self,
2251 handle: &Model<T>,
2252 read: impl FnOnce(&T, &AppContext) -> R,
2253 ) -> Self::Result<R>
2254 where
2255 T: 'static,
2256 {
2257 self.window_cx.read_model(handle, read)
2258 }
2259
2260 fn read_window<R>(
2261 &self,
2262 window: &AnyWindowHandle,
2263 read: impl FnOnce(AnyView, &AppContext) -> R,
2264 ) -> Result<R> {
2265 self.window_cx.read_window(window, read)
2266 }
2267}
2268
2269impl<V: 'static> VisualContext for ViewContext<'_, V> {
2270 fn build_view<W: Render + 'static>(
2271 &mut self,
2272 build_view_state: impl FnOnce(&mut ViewContext<'_, W>) -> W,
2273 ) -> Self::Result<View<W>> {
2274 self.window_cx.build_view(build_view_state)
2275 }
2276
2277 fn update_view<V2: 'static, R>(
2278 &mut self,
2279 view: &View<V2>,
2280 update: impl FnOnce(&mut V2, &mut ViewContext<'_, V2>) -> R,
2281 ) -> Self::Result<R> {
2282 self.window_cx.update_view(view, update)
2283 }
2284
2285 fn replace_root_view<W>(
2286 &mut self,
2287 build_view: impl FnOnce(&mut ViewContext<'_, W>) -> W,
2288 ) -> Self::Result<View<W>>
2289 where
2290 W: Render,
2291 {
2292 self.window_cx.replace_root_view(build_view)
2293 }
2294}
2295
2296impl<'a, V> std::ops::Deref for ViewContext<'a, V> {
2297 type Target = WindowContext<'a>;
2298
2299 fn deref(&self) -> &Self::Target {
2300 &self.window_cx
2301 }
2302}
2303
2304impl<'a, V> std::ops::DerefMut for ViewContext<'a, V> {
2305 fn deref_mut(&mut self) -> &mut Self::Target {
2306 &mut self.window_cx
2307 }
2308}
2309
2310// #[derive(Clone, Copy, Eq, PartialEq, Hash)]
2311slotmap::new_key_type! { pub struct WindowId; }
2312
2313impl WindowId {
2314 pub fn as_u64(&self) -> u64 {
2315 self.0.as_ffi()
2316 }
2317}
2318
2319#[derive(Deref, DerefMut)]
2320pub struct WindowHandle<V> {
2321 #[deref]
2322 #[deref_mut]
2323 pub(crate) any_handle: AnyWindowHandle,
2324 state_type: PhantomData<V>,
2325}
2326
2327impl<V: 'static + Render> WindowHandle<V> {
2328 pub fn new(id: WindowId) -> Self {
2329 WindowHandle {
2330 any_handle: AnyWindowHandle {
2331 id,
2332 state_type: TypeId::of::<V>(),
2333 },
2334 state_type: PhantomData,
2335 }
2336 }
2337
2338 pub fn root<C: Context>(&self, cx: &C) -> Result<View<V>> {
2339 cx.read_window(&self.any_handle, |root_view, _| {
2340 root_view
2341 .downcast::<V>()
2342 .map_err(|_| anyhow!("the type of the window's root view has changed"))
2343 })?
2344 }
2345
2346 pub fn update<C, R>(
2347 self,
2348 cx: &mut C,
2349 update: impl FnOnce(&mut V, &mut ViewContext<'_, V>) -> R,
2350 ) -> Result<R>
2351 where
2352 C: Context,
2353 {
2354 cx.update_window(self.any_handle, |root_view, cx| {
2355 let view = root_view
2356 .downcast::<V>()
2357 .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
2358 Ok(cx.update_view(&view, update))
2359 })?
2360 }
2361}
2362
2363impl<V> Copy for WindowHandle<V> {}
2364
2365impl<V> Clone for WindowHandle<V> {
2366 fn clone(&self) -> Self {
2367 WindowHandle {
2368 any_handle: self.any_handle,
2369 state_type: PhantomData,
2370 }
2371 }
2372}
2373
2374impl<V> PartialEq for WindowHandle<V> {
2375 fn eq(&self, other: &Self) -> bool {
2376 self.any_handle == other.any_handle
2377 }
2378}
2379
2380impl<V> Eq for WindowHandle<V> {}
2381
2382impl<V> Hash for WindowHandle<V> {
2383 fn hash<H: Hasher>(&self, state: &mut H) {
2384 self.any_handle.hash(state);
2385 }
2386}
2387
2388impl<V: 'static> Into<AnyWindowHandle> for WindowHandle<V> {
2389 fn into(self) -> AnyWindowHandle {
2390 self.any_handle
2391 }
2392}
2393
2394#[derive(Copy, Clone, PartialEq, Eq, Hash)]
2395pub struct AnyWindowHandle {
2396 pub(crate) id: WindowId,
2397 state_type: TypeId,
2398}
2399
2400impl AnyWindowHandle {
2401 pub fn window_id(&self) -> WindowId {
2402 self.id
2403 }
2404
2405 pub fn downcast<T: 'static>(&self) -> Option<WindowHandle<T>> {
2406 if TypeId::of::<T>() == self.state_type {
2407 Some(WindowHandle {
2408 any_handle: *self,
2409 state_type: PhantomData,
2410 })
2411 } else {
2412 None
2413 }
2414 }
2415
2416 pub fn update<C, R>(
2417 self,
2418 cx: &mut C,
2419 update: impl FnOnce(AnyView, &mut WindowContext<'_>) -> R,
2420 ) -> Result<R>
2421 where
2422 C: Context,
2423 {
2424 cx.update_window(self, update)
2425 }
2426
2427 pub fn read<C, R>(self, cx: &C, read: impl FnOnce(AnyView, &AppContext) -> R) -> Result<R>
2428 where
2429 C: Context,
2430 {
2431 cx.read_window(&self, read)
2432 }
2433}
2434
2435#[cfg(any(test, feature = "test-support"))]
2436impl From<SmallVec<[u32; 16]>> for StackingOrder {
2437 fn from(small_vec: SmallVec<[u32; 16]>) -> Self {
2438 StackingOrder(small_vec)
2439 }
2440}
2441
2442#[derive(Clone, Debug, Eq, PartialEq, Hash)]
2443pub enum ElementId {
2444 View(EntityId),
2445 Number(usize),
2446 Name(SharedString),
2447 FocusHandle(FocusId),
2448}
2449
2450impl From<EntityId> for ElementId {
2451 fn from(id: EntityId) -> Self {
2452 ElementId::View(id)
2453 }
2454}
2455
2456impl From<usize> for ElementId {
2457 fn from(id: usize) -> Self {
2458 ElementId::Number(id)
2459 }
2460}
2461
2462impl From<i32> for ElementId {
2463 fn from(id: i32) -> Self {
2464 Self::Number(id as usize)
2465 }
2466}
2467
2468impl From<SharedString> for ElementId {
2469 fn from(name: SharedString) -> Self {
2470 ElementId::Name(name)
2471 }
2472}
2473
2474impl From<&'static str> for ElementId {
2475 fn from(name: &'static str) -> Self {
2476 ElementId::Name(name.into())
2477 }
2478}
2479
2480impl<'a> From<&'a FocusHandle> for ElementId {
2481 fn from(handle: &'a FocusHandle) -> Self {
2482 ElementId::FocusHandle(handle.id)
2483 }
2484}