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