1use crate::{
2 build_action_from_type, px, size, Action, AnyBox, AnyDrag, AnyView, AppContext,
3 AsyncWindowContext, AvailableSpace, Bounds, BoxShadow, Context, Corners, CursorStyle,
4 DevicePixels, DispatchContext, DisplayId, Edges, Effect, Entity, EntityId, EventEmitter,
5 FileDropEvent, FocusEvent, FontId, GlobalElementId, GlyphId, Hsla, ImageData, InputEvent,
6 IsZero, KeyListener, KeyMatch, KeyMatcher, Keystroke, LayoutId, Model, ModelContext, Modifiers,
7 MonochromeSprite, MouseButton, MouseDownEvent, MouseMoveEvent, MouseUpEvent, Path, Pixels,
8 PlatformAtlas, PlatformDisplay, PlatformInputHandler, PlatformWindow, Point, PolychromeSprite,
9 PromptLevel, Quad, Render, RenderGlyphParams, RenderImageParams, RenderSvgParams, ScaledPixels,
10 SceneBuilder, Shadow, SharedString, Size, Style, SubscriberSet, Subscription,
11 TaffyLayoutEngine, Task, Underline, UnderlineStyle, View, VisualContext, WeakView,
12 WindowBounds, WindowOptions, SUBPIXEL_VARIANTS,
13};
14use anyhow::{anyhow, 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 AnyListener = Box<dyn FnMut(&dyn Any, DispatchPhase, &mut WindowContext) + 'static>;
64type AnyKeyListener = Box<
65 dyn Fn(
66 &dyn Any,
67 &[&DispatchContext],
68 DispatchPhase,
69 &mut WindowContext,
70 ) -> Option<Box<dyn Action>>
71 + 'static,
72>;
73type AnyFocusListener = Box<dyn Fn(&FocusEvent, &mut WindowContext) + 'static>;
74type AnyWindowFocusListener = Box<dyn FnMut(&FocusEvent, &mut WindowContext) -> bool + 'static>;
75
76slotmap::new_key_type! { pub struct FocusId; }
77
78impl FocusId {
79 /// Obtains whether the element associated with this handle is currently focused.
80 pub fn is_focused(&self, cx: &WindowContext) -> bool {
81 cx.window.focus == Some(*self)
82 }
83
84 /// Obtains whether the element associated with this handle contains the focused
85 /// element or is itself focused.
86 pub fn contains_focused(&self, cx: &WindowContext) -> bool {
87 cx.focused()
88 .map_or(false, |focused| self.contains(focused.id, cx))
89 }
90
91 /// Obtains whether the element associated with this handle is contained within the
92 /// focused element or is itself focused.
93 pub fn within_focused(&self, cx: &WindowContext) -> bool {
94 let focused = cx.focused();
95 focused.map_or(false, |focused| focused.id.contains(*self, cx))
96 }
97
98 /// Obtains whether this handle contains the given handle in the most recently rendered frame.
99 pub(crate) fn contains(&self, other: Self, cx: &WindowContext) -> bool {
100 let mut ancestor = Some(other);
101 while let Some(ancestor_id) = ancestor {
102 if *self == ancestor_id {
103 return true;
104 } else {
105 ancestor = cx
106 .window
107 .current_frame
108 .focus_parents_by_child
109 .get(&ancestor_id)
110 .copied();
111 }
112 }
113 false
114 }
115}
116
117/// A handle which can be used to track and manipulate the focused element in a window.
118pub struct FocusHandle {
119 pub(crate) id: FocusId,
120 handles: Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>,
121}
122
123impl FocusHandle {
124 pub(crate) fn new(handles: &Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>) -> Self {
125 let id = handles.write().insert(AtomicUsize::new(1));
126 Self {
127 id,
128 handles: handles.clone(),
129 }
130 }
131
132 pub(crate) fn for_id(
133 id: FocusId,
134 handles: &Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>,
135 ) -> Option<Self> {
136 let lock = handles.read();
137 let ref_count = lock.get(id)?;
138 if ref_count.load(SeqCst) == 0 {
139 None
140 } else {
141 ref_count.fetch_add(1, SeqCst);
142 Some(Self {
143 id,
144 handles: handles.clone(),
145 })
146 }
147 }
148
149 /// Moves the focus to the element associated with this handle.
150 pub fn focus(&self, cx: &mut WindowContext) {
151 cx.focus(self)
152 }
153
154 /// Obtains whether the element associated with this handle is currently focused.
155 pub fn is_focused(&self, cx: &WindowContext) -> bool {
156 self.id.is_focused(cx)
157 }
158
159 /// Obtains whether the element associated with this handle contains the focused
160 /// element or is itself focused.
161 pub fn contains_focused(&self, cx: &WindowContext) -> bool {
162 self.id.contains_focused(cx)
163 }
164
165 /// Obtains whether the element associated with this handle is contained within the
166 /// focused element or is itself focused.
167 pub fn within_focused(&self, cx: &WindowContext) -> bool {
168 self.id.within_focused(cx)
169 }
170
171 /// Obtains whether this handle contains the given handle in the most recently rendered frame.
172 pub(crate) fn contains(&self, other: &Self, cx: &WindowContext) -> bool {
173 self.id.contains(other.id, cx)
174 }
175}
176
177impl Clone for FocusHandle {
178 fn clone(&self) -> Self {
179 Self::for_id(self.id, &self.handles).unwrap()
180 }
181}
182
183impl PartialEq for FocusHandle {
184 fn eq(&self, other: &Self) -> bool {
185 self.id == other.id
186 }
187}
188
189impl Eq for FocusHandle {}
190
191impl Drop for FocusHandle {
192 fn drop(&mut self) {
193 self.handles
194 .read()
195 .get(self.id)
196 .unwrap()
197 .fetch_sub(1, SeqCst);
198 }
199}
200
201// Holds the state for a specific window.
202pub struct Window {
203 pub(crate) handle: AnyWindowHandle,
204 pub(crate) removed: bool,
205 platform_window: Box<dyn PlatformWindow>,
206 display_id: DisplayId,
207 sprite_atlas: Arc<dyn PlatformAtlas>,
208 rem_size: Pixels,
209 content_size: Size<Pixels>,
210 pub(crate) layout_engine: TaffyLayoutEngine,
211 pub(crate) root_view: Option<AnyView>,
212 pub(crate) element_id_stack: GlobalElementId,
213 pub(crate) previous_frame: Frame,
214 pub(crate) current_frame: Frame,
215 pub(crate) focus_handles: Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>,
216 pub(crate) focus_listeners: SubscriberSet<(), AnyWindowFocusListener>,
217 default_prevented: bool,
218 mouse_position: Point<Pixels>,
219 requested_cursor_style: Option<CursorStyle>,
220 scale_factor: f32,
221 bounds: WindowBounds,
222 bounds_observers: SubscriberSet<(), AnyObserver>,
223 active: bool,
224 activation_observers: SubscriberSet<(), AnyObserver>,
225 pub(crate) dirty: bool,
226 pub(crate) last_blur: Option<Option<FocusId>>,
227 pub(crate) focus: Option<FocusId>,
228}
229
230#[derive(Default)]
231pub(crate) struct Frame {
232 element_states: HashMap<GlobalElementId, AnyBox>,
233 key_matchers: HashMap<GlobalElementId, KeyMatcher>,
234 mouse_listeners: HashMap<TypeId, Vec<(StackingOrder, AnyListener)>>,
235 pub(crate) focus_listeners: Vec<AnyFocusListener>,
236 pub(crate) key_dispatch_stack: Vec<KeyDispatchStackFrame>,
237 freeze_key_dispatch_stack: bool,
238 focus_parents_by_child: HashMap<FocusId, FocusId>,
239 pub(crate) scene_builder: SceneBuilder,
240 z_index_stack: StackingOrder,
241 content_mask_stack: Vec<ContentMask<Pixels>>,
242 element_offset_stack: Vec<Point<Pixels>>,
243 focus_stack: Vec<FocusId>,
244}
245
246impl Window {
247 pub(crate) fn new(
248 handle: AnyWindowHandle,
249 options: WindowOptions,
250 cx: &mut AppContext,
251 ) -> Self {
252 let platform_window = cx.platform.open_window(handle, options);
253 let display_id = platform_window.display().id();
254 let sprite_atlas = platform_window.sprite_atlas();
255 let mouse_position = platform_window.mouse_position();
256 let content_size = platform_window.content_size();
257 let scale_factor = platform_window.scale_factor();
258 let bounds = platform_window.bounds();
259
260 platform_window.on_resize(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_moved(Box::new({
269 let mut cx = cx.to_async();
270 move || {
271 handle
272 .update(&mut cx, |_, cx| cx.window_bounds_changed())
273 .log_err();
274 }
275 }));
276 platform_window.on_active_status_change(Box::new({
277 let mut cx = cx.to_async();
278 move |active| {
279 handle
280 .update(&mut cx, |_, cx| {
281 cx.window.active = active;
282 cx.window
283 .activation_observers
284 .clone()
285 .retain(&(), |callback| callback(cx));
286 })
287 .log_err();
288 }
289 }));
290
291 platform_window.on_input({
292 let mut cx = cx.to_async();
293 Box::new(move |event| {
294 handle
295 .update(&mut cx, |_, cx| cx.dispatch_event(event))
296 .log_err()
297 .unwrap_or(false)
298 })
299 });
300
301 Window {
302 handle,
303 removed: false,
304 platform_window,
305 display_id,
306 sprite_atlas,
307 rem_size: px(16.),
308 content_size,
309 layout_engine: TaffyLayoutEngine::new(),
310 root_view: None,
311 element_id_stack: GlobalElementId::default(),
312 previous_frame: Frame::default(),
313 current_frame: Frame::default(),
314 focus_handles: Arc::new(RwLock::new(SlotMap::with_key())),
315 focus_listeners: SubscriberSet::new(),
316 default_prevented: true,
317 mouse_position,
318 requested_cursor_style: None,
319 scale_factor,
320 bounds,
321 bounds_observers: SubscriberSet::new(),
322 active: false,
323 activation_observers: SubscriberSet::new(),
324 dirty: true,
325 last_blur: None,
326 focus: None,
327 }
328 }
329}
330
331/// When constructing the element tree, we maintain a stack of key dispatch frames until we
332/// find the focused element. We interleave key listeners with dispatch contexts so we can use the
333/// contexts when matching key events against the keymap. A key listener can be either an action
334/// handler or a [KeyDown] / [KeyUp] event listener.
335pub(crate) enum KeyDispatchStackFrame {
336 Listener {
337 event_type: TypeId,
338 listener: AnyKeyListener,
339 },
340 Context(DispatchContext),
341}
342
343/// Indicates which region of the window is visible. Content falling outside of this mask will not be
344/// rendered. Currently, only rectangular content masks are supported, but we give the mask its own type
345/// to leave room to support more complex shapes in the future.
346#[derive(Clone, Debug, Default, PartialEq, Eq)]
347#[repr(C)]
348pub struct ContentMask<P: Clone + Default + Debug> {
349 pub bounds: Bounds<P>,
350}
351
352impl ContentMask<Pixels> {
353 /// Scale the content mask's pixel units by the given scaling factor.
354 pub fn scale(&self, factor: f32) -> ContentMask<ScaledPixels> {
355 ContentMask {
356 bounds: self.bounds.scale(factor),
357 }
358 }
359
360 /// Intersect the content mask with the given content mask.
361 pub fn intersect(&self, other: &Self) -> Self {
362 let bounds = self.bounds.intersect(&other.bounds);
363 ContentMask { bounds }
364 }
365}
366
367/// Provides access to application state in the context of a single window. Derefs
368/// to an `AppContext`, so you can also pass a `WindowContext` to any method that takes
369/// an `AppContext` and call any `AppContext` methods.
370pub struct WindowContext<'a> {
371 pub(crate) app: &'a mut AppContext,
372 pub(crate) window: &'a mut Window,
373}
374
375impl<'a> WindowContext<'a> {
376 pub(crate) fn new(app: &'a mut AppContext, window: &'a mut Window) -> Self {
377 Self { app, window }
378 }
379
380 /// Obtain a handle to the window that belongs to this context.
381 pub fn window_handle(&self) -> AnyWindowHandle {
382 self.window.handle
383 }
384
385 /// Mark the window as dirty, scheduling it to be redrawn on the next frame.
386 pub fn notify(&mut self) {
387 self.window.dirty = true;
388 }
389
390 /// Close this window.
391 pub fn remove_window(&mut self) {
392 self.window.removed = true;
393 }
394
395 /// Obtain a new `FocusHandle`, which allows you to track and manipulate the keyboard focus
396 /// for elements rendered within this window.
397 pub fn focus_handle(&mut self) -> FocusHandle {
398 FocusHandle::new(&self.window.focus_handles)
399 }
400
401 /// Obtain the currently focused `FocusHandle`. If no elements are focused, returns `None`.
402 pub fn focused(&self) -> Option<FocusHandle> {
403 self.window
404 .focus
405 .and_then(|id| FocusHandle::for_id(id, &self.window.focus_handles))
406 }
407
408 /// Move focus to the element associated with the given `FocusHandle`.
409 pub fn focus(&mut self, handle: &FocusHandle) {
410 if self.window.last_blur.is_none() {
411 self.window.last_blur = Some(self.window.focus);
412 }
413
414 self.window.focus = Some(handle.id);
415
416 // self.window.current_frame.key_dispatch_stack.clear()
417 // self.window.root_view.initialize()
418 self.app.push_effect(Effect::FocusChanged {
419 window_handle: self.window.handle,
420 focused: Some(handle.id),
421 });
422 self.notify();
423 }
424
425 /// Remove focus from all elements within this context's window.
426 pub fn blur(&mut self) {
427 if self.window.last_blur.is_none() {
428 self.window.last_blur = Some(self.window.focus);
429 }
430
431 self.window.focus = None;
432 self.app.push_effect(Effect::FocusChanged {
433 window_handle: self.window.handle,
434 focused: None,
435 });
436 self.notify();
437 }
438
439 pub fn dispatch_action(&mut self, action: Box<dyn Action>) {
440 self.defer(|cx| {
441 cx.app.propagate_event = true;
442 let stack = cx.dispatch_stack();
443 cx.dispatch_action_internal(action, &stack[..])
444 })
445 }
446
447 /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
448 /// that are currently on the stack to be returned to the app.
449 pub fn defer(&mut self, f: impl FnOnce(&mut WindowContext) + 'static) {
450 let handle = self.window.handle;
451 self.app.defer(move |cx| {
452 handle.update(cx, |_, cx| f(cx)).ok();
453 });
454 }
455
456 pub fn subscribe<Emitter, E, Evt>(
457 &mut self,
458 entity: &E,
459 mut on_event: impl FnMut(E, &Evt, &mut WindowContext<'_>) + 'static,
460 ) -> Subscription
461 where
462 Emitter: EventEmitter<Evt>,
463 E: Entity<Emitter>,
464 Evt: 'static,
465 {
466 let entity_id = entity.entity_id();
467 let entity = entity.downgrade();
468 let window_handle = self.window.handle;
469 self.app.event_listeners.insert(
470 entity_id,
471 (
472 TypeId::of::<Evt>(),
473 Box::new(move |event, cx| {
474 window_handle
475 .update(cx, |_, cx| {
476 if let Some(handle) = E::upgrade_from(&entity) {
477 let event = event.downcast_ref().expect("invalid event type");
478 on_event(handle, event, cx);
479 true
480 } else {
481 false
482 }
483 })
484 .unwrap_or(false)
485 }),
486 ),
487 )
488 }
489
490 /// Create an `AsyncWindowContext`, which has a static lifetime and can be held across
491 /// await points in async code.
492 pub fn to_async(&self) -> AsyncWindowContext {
493 AsyncWindowContext::new(self.app.to_async(), self.window.handle)
494 }
495
496 /// Schedule the given closure to be run directly after the current frame is rendered.
497 pub fn on_next_frame(&mut self, callback: impl FnOnce(&mut WindowContext) + 'static) {
498 let handle = self.window.handle;
499 let display_id = self.window.display_id;
500
501 if !self.frame_consumers.contains_key(&display_id) {
502 let (tx, mut rx) = mpsc::unbounded::<()>();
503 self.platform.set_display_link_output_callback(
504 display_id,
505 Box::new(move |_current_time, _output_time| _ = tx.unbounded_send(())),
506 );
507
508 let consumer_task = self.app.spawn(|cx| async move {
509 while rx.next().await.is_some() {
510 cx.update(|cx| {
511 for callback in cx
512 .next_frame_callbacks
513 .get_mut(&display_id)
514 .unwrap()
515 .drain(..)
516 .collect::<SmallVec<[_; 32]>>()
517 {
518 callback(cx);
519 }
520 })
521 .ok();
522
523 // Flush effects, then stop the display link if no new next_frame_callbacks have been added.
524
525 cx.update(|cx| {
526 if cx.next_frame_callbacks.is_empty() {
527 cx.platform.stop_display_link(display_id);
528 }
529 })
530 .ok();
531 }
532 });
533 self.frame_consumers.insert(display_id, consumer_task);
534 }
535
536 if self.next_frame_callbacks.is_empty() {
537 self.platform.start_display_link(display_id);
538 }
539
540 self.next_frame_callbacks
541 .entry(display_id)
542 .or_default()
543 .push(Box::new(move |cx: &mut AppContext| {
544 cx.update_window(handle, |_root_view, cx| callback(cx)).ok();
545 }));
546 }
547
548 /// Spawn the future returned by the given closure on the application thread pool.
549 /// The closure is provided a handle to the current window and an `AsyncWindowContext` for
550 /// use within your future.
551 pub fn spawn<Fut, R>(&mut self, f: impl FnOnce(AsyncWindowContext) -> Fut) -> Task<R>
552 where
553 R: 'static,
554 Fut: Future<Output = R> + 'static,
555 {
556 self.app
557 .spawn(|app| f(AsyncWindowContext::new(app, self.window.handle)))
558 }
559
560 /// Update the global of the given type. The given closure is given simultaneous mutable
561 /// access both to the global and the context.
562 pub fn update_global<G, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R
563 where
564 G: 'static,
565 {
566 let mut global = self.app.lease_global::<G>();
567 let result = f(&mut global, self);
568 self.app.end_global_lease(global);
569 result
570 }
571
572 /// Add a node to the layout tree for the current frame. Takes the `Style` of the element for which
573 /// layout is being requested, along with the layout ids of any children. This method is called during
574 /// calls to the `Element::layout` trait method and enables any element to participate in layout.
575 pub fn request_layout(
576 &mut self,
577 style: &Style,
578 children: impl IntoIterator<Item = LayoutId>,
579 ) -> LayoutId {
580 self.app.layout_id_buffer.clear();
581 self.app.layout_id_buffer.extend(children.into_iter());
582 let rem_size = self.rem_size();
583
584 self.window
585 .layout_engine
586 .request_layout(style, rem_size, &self.app.layout_id_buffer)
587 }
588
589 /// Add a node to the layout tree for the current frame. Instead of taking a `Style` and children,
590 /// this variant takes a function that is invoked during layout so you can use arbitrary logic to
591 /// determine the element's size. One place this is used internally is when measuring text.
592 ///
593 /// The given closure is invoked at layout time with the known dimensions and available space and
594 /// returns a `Size`.
595 pub fn request_measured_layout<
596 F: Fn(Size<Option<Pixels>>, Size<AvailableSpace>) -> Size<Pixels> + Send + Sync + 'static,
597 >(
598 &mut self,
599 style: Style,
600 rem_size: Pixels,
601 measure: F,
602 ) -> LayoutId {
603 self.window
604 .layout_engine
605 .request_measured_layout(style, rem_size, measure)
606 }
607
608 pub fn compute_layout(&mut self, layout_id: LayoutId, available_space: Size<AvailableSpace>) {
609 self.window
610 .layout_engine
611 .compute_layout(layout_id, available_space)
612 }
613
614 /// Obtain the bounds computed for the given LayoutId relative to the window. This method should not
615 /// be invoked until the paint phase begins, and will usually be invoked by GPUI itself automatically
616 /// in order to pass your element its `Bounds` automatically.
617 pub fn layout_bounds(&mut self, layout_id: LayoutId) -> Bounds<Pixels> {
618 let mut bounds = self
619 .window
620 .layout_engine
621 .layout_bounds(layout_id)
622 .map(Into::into);
623 bounds.origin += self.element_offset();
624 bounds
625 }
626
627 fn window_bounds_changed(&mut self) {
628 self.window.scale_factor = self.window.platform_window.scale_factor();
629 self.window.content_size = self.window.platform_window.content_size();
630 self.window.bounds = self.window.platform_window.bounds();
631 self.window.display_id = self.window.platform_window.display().id();
632 self.window.dirty = true;
633
634 self.window
635 .bounds_observers
636 .clone()
637 .retain(&(), |callback| callback(self));
638 }
639
640 pub fn window_bounds(&self) -> WindowBounds {
641 self.window.bounds
642 }
643
644 pub fn is_window_active(&self) -> bool {
645 self.window.active
646 }
647
648 pub fn zoom_window(&self) {
649 self.window.platform_window.zoom();
650 }
651
652 pub fn display(&self) -> Option<Rc<dyn PlatformDisplay>> {
653 self.platform
654 .displays()
655 .into_iter()
656 .find(|display| display.id() == self.window.display_id)
657 }
658
659 pub fn show_character_palette(&self) {
660 self.window.platform_window.show_character_palette();
661 }
662
663 /// The scale factor of the display associated with the window. For example, it could
664 /// return 2.0 for a "retina" display, indicating that each logical pixel should actually
665 /// be rendered as two pixels on screen.
666 pub fn scale_factor(&self) -> f32 {
667 self.window.scale_factor
668 }
669
670 /// The size of an em for the base font of the application. Adjusting this value allows the
671 /// UI to scale, just like zooming a web page.
672 pub fn rem_size(&self) -> Pixels {
673 self.window.rem_size
674 }
675
676 /// Sets the size of an em for the base font of the application. Adjusting this value allows the
677 /// UI to scale, just like zooming a web page.
678 pub fn set_rem_size(&mut self, rem_size: impl Into<Pixels>) {
679 self.window.rem_size = rem_size.into();
680 }
681
682 /// The line height associated with the current text style.
683 pub fn line_height(&self) -> Pixels {
684 let rem_size = self.rem_size();
685 let text_style = self.text_style();
686 text_style
687 .line_height
688 .to_pixels(text_style.font_size.into(), rem_size)
689 }
690
691 /// Call to prevent the default action of an event. Currently only used to prevent
692 /// parent elements from becoming focused on mouse down.
693 pub fn prevent_default(&mut self) {
694 self.window.default_prevented = true;
695 }
696
697 /// Obtain whether default has been prevented for the event currently being dispatched.
698 pub fn default_prevented(&self) -> bool {
699 self.window.default_prevented
700 }
701
702 /// Register a mouse event listener on the window for the current frame. The type of event
703 /// is determined by the first parameter of the given listener. When the next frame is rendered
704 /// the listener will be cleared.
705 ///
706 /// This is a fairly low-level method, so prefer using event handlers on elements unless you have
707 /// a specific need to register a global listener.
708 pub fn on_mouse_event<Event: 'static>(
709 &mut self,
710 handler: impl Fn(&Event, DispatchPhase, &mut WindowContext) + 'static,
711 ) {
712 let order = self.window.current_frame.z_index_stack.clone();
713 self.window
714 .current_frame
715 .mouse_listeners
716 .entry(TypeId::of::<Event>())
717 .or_default()
718 .push((
719 order,
720 Box::new(move |event: &dyn Any, phase, cx| {
721 handler(event.downcast_ref().unwrap(), phase, cx)
722 }),
723 ))
724 }
725
726 /// The position of the mouse relative to the window.
727 pub fn mouse_position(&self) -> Point<Pixels> {
728 self.window.mouse_position
729 }
730
731 pub fn set_cursor_style(&mut self, style: CursorStyle) {
732 self.window.requested_cursor_style = Some(style)
733 }
734
735 /// Called during painting to invoke the given closure in a new stacking context. The given
736 /// z-index is interpreted relative to the previous call to `stack`.
737 pub fn stack<R>(&mut self, z_index: u32, f: impl FnOnce(&mut Self) -> R) -> R {
738 self.window.current_frame.z_index_stack.push(z_index);
739 let result = f(self);
740 self.window.current_frame.z_index_stack.pop();
741 result
742 }
743
744 /// Paint one or more drop shadows into the scene for the current frame at the current z-index.
745 pub fn paint_shadows(
746 &mut self,
747 bounds: Bounds<Pixels>,
748 corner_radii: Corners<Pixels>,
749 shadows: &[BoxShadow],
750 ) {
751 let scale_factor = self.scale_factor();
752 let content_mask = self.content_mask();
753 let window = &mut *self.window;
754 for shadow in shadows {
755 let mut shadow_bounds = bounds;
756 shadow_bounds.origin += shadow.offset;
757 shadow_bounds.dilate(shadow.spread_radius);
758 window.current_frame.scene_builder.insert(
759 &window.current_frame.z_index_stack,
760 Shadow {
761 order: 0,
762 bounds: shadow_bounds.scale(scale_factor),
763 content_mask: content_mask.scale(scale_factor),
764 corner_radii: corner_radii.scale(scale_factor),
765 color: shadow.color,
766 blur_radius: shadow.blur_radius.scale(scale_factor),
767 },
768 );
769 }
770 }
771
772 /// Paint one or more quads into the scene for the current frame at the current stacking context.
773 /// Quads are colored rectangular regions with an optional background, border, and corner radius.
774 pub fn paint_quad(
775 &mut self,
776 bounds: Bounds<Pixels>,
777 corner_radii: Corners<Pixels>,
778 background: impl Into<Hsla>,
779 border_widths: Edges<Pixels>,
780 border_color: impl Into<Hsla>,
781 ) {
782 let scale_factor = self.scale_factor();
783 let content_mask = self.content_mask();
784
785 let window = &mut *self.window;
786 window.current_frame.scene_builder.insert(
787 &window.current_frame.z_index_stack,
788 Quad {
789 order: 0,
790 bounds: bounds.scale(scale_factor),
791 content_mask: content_mask.scale(scale_factor),
792 background: background.into(),
793 border_color: border_color.into(),
794 corner_radii: corner_radii.scale(scale_factor),
795 border_widths: border_widths.scale(scale_factor),
796 },
797 );
798 }
799
800 /// Paint the given `Path` into the scene for the current frame at the current z-index.
801 pub fn paint_path(&mut self, mut path: Path<Pixels>, color: impl Into<Hsla>) {
802 let scale_factor = self.scale_factor();
803 let content_mask = self.content_mask();
804 path.content_mask = content_mask;
805 path.color = color.into();
806 let window = &mut *self.window;
807 window.current_frame.scene_builder.insert(
808 &window.current_frame.z_index_stack,
809 path.scale(scale_factor),
810 );
811 }
812
813 /// Paint an underline into the scene for the current frame at the current z-index.
814 pub fn paint_underline(
815 &mut self,
816 origin: Point<Pixels>,
817 width: Pixels,
818 style: &UnderlineStyle,
819 ) -> Result<()> {
820 let scale_factor = self.scale_factor();
821 let height = if style.wavy {
822 style.thickness * 3.
823 } else {
824 style.thickness
825 };
826 let bounds = Bounds {
827 origin,
828 size: size(width, height),
829 };
830 let content_mask = self.content_mask();
831 let window = &mut *self.window;
832 window.current_frame.scene_builder.insert(
833 &window.current_frame.z_index_stack,
834 Underline {
835 order: 0,
836 bounds: bounds.scale(scale_factor),
837 content_mask: content_mask.scale(scale_factor),
838 thickness: style.thickness.scale(scale_factor),
839 color: style.color.unwrap_or_default(),
840 wavy: style.wavy,
841 },
842 );
843 Ok(())
844 }
845
846 /// Paint a monochrome (non-emoji) glyph into the scene for the current frame at the current z-index.
847 /// The y component of the origin is the baseline of the glyph.
848 pub fn paint_glyph(
849 &mut self,
850 origin: Point<Pixels>,
851 font_id: FontId,
852 glyph_id: GlyphId,
853 font_size: Pixels,
854 color: Hsla,
855 ) -> Result<()> {
856 let scale_factor = self.scale_factor();
857 let glyph_origin = origin.scale(scale_factor);
858 let subpixel_variant = Point {
859 x: (glyph_origin.x.0.fract() * SUBPIXEL_VARIANTS as f32).floor() as u8,
860 y: (glyph_origin.y.0.fract() * SUBPIXEL_VARIANTS as f32).floor() as u8,
861 };
862 let params = RenderGlyphParams {
863 font_id,
864 glyph_id,
865 font_size,
866 subpixel_variant,
867 scale_factor,
868 is_emoji: false,
869 };
870
871 let raster_bounds = self.text_system().raster_bounds(¶ms)?;
872 if !raster_bounds.is_zero() {
873 let tile =
874 self.window
875 .sprite_atlas
876 .get_or_insert_with(¶ms.clone().into(), &mut || {
877 let (size, bytes) = self.text_system().rasterize_glyph(¶ms)?;
878 Ok((size, Cow::Owned(bytes)))
879 })?;
880 let bounds = Bounds {
881 origin: glyph_origin.map(|px| px.floor()) + raster_bounds.origin.map(Into::into),
882 size: tile.bounds.size.map(Into::into),
883 };
884 let content_mask = self.content_mask().scale(scale_factor);
885 let window = &mut *self.window;
886 window.current_frame.scene_builder.insert(
887 &window.current_frame.z_index_stack,
888 MonochromeSprite {
889 order: 0,
890 bounds,
891 content_mask,
892 color,
893 tile,
894 },
895 );
896 }
897 Ok(())
898 }
899
900 /// Paint an emoji glyph into the scene for the current frame at the current z-index.
901 /// The y component of the origin is the baseline of the glyph.
902 pub fn paint_emoji(
903 &mut self,
904 origin: Point<Pixels>,
905 font_id: FontId,
906 glyph_id: GlyphId,
907 font_size: Pixels,
908 ) -> Result<()> {
909 let scale_factor = self.scale_factor();
910 let glyph_origin = origin.scale(scale_factor);
911 let params = RenderGlyphParams {
912 font_id,
913 glyph_id,
914 font_size,
915 // We don't render emojis with subpixel variants.
916 subpixel_variant: Default::default(),
917 scale_factor,
918 is_emoji: true,
919 };
920
921 let raster_bounds = self.text_system().raster_bounds(¶ms)?;
922 if !raster_bounds.is_zero() {
923 let tile =
924 self.window
925 .sprite_atlas
926 .get_or_insert_with(¶ms.clone().into(), &mut || {
927 let (size, bytes) = self.text_system().rasterize_glyph(¶ms)?;
928 Ok((size, Cow::Owned(bytes)))
929 })?;
930 let bounds = Bounds {
931 origin: glyph_origin.map(|px| px.floor()) + raster_bounds.origin.map(Into::into),
932 size: tile.bounds.size.map(Into::into),
933 };
934 let content_mask = self.content_mask().scale(scale_factor);
935 let window = &mut *self.window;
936
937 window.current_frame.scene_builder.insert(
938 &window.current_frame.z_index_stack,
939 PolychromeSprite {
940 order: 0,
941 bounds,
942 corner_radii: Default::default(),
943 content_mask,
944 tile,
945 grayscale: false,
946 },
947 );
948 }
949 Ok(())
950 }
951
952 /// Paint a monochrome SVG into the scene for the current frame at the current stacking context.
953 pub fn paint_svg(
954 &mut self,
955 bounds: Bounds<Pixels>,
956 path: SharedString,
957 color: Hsla,
958 ) -> Result<()> {
959 let scale_factor = self.scale_factor();
960 let bounds = bounds.scale(scale_factor);
961 // Render the SVG at twice the size to get a higher quality result.
962 let params = RenderSvgParams {
963 path,
964 size: bounds
965 .size
966 .map(|pixels| DevicePixels::from((pixels.0 * 2.).ceil() as i32)),
967 };
968
969 let tile =
970 self.window
971 .sprite_atlas
972 .get_or_insert_with(¶ms.clone().into(), &mut || {
973 let bytes = self.svg_renderer.render(¶ms)?;
974 Ok((params.size, Cow::Owned(bytes)))
975 })?;
976 let content_mask = self.content_mask().scale(scale_factor);
977
978 let window = &mut *self.window;
979 window.current_frame.scene_builder.insert(
980 &window.current_frame.z_index_stack,
981 MonochromeSprite {
982 order: 0,
983 bounds,
984 content_mask,
985 color,
986 tile,
987 },
988 );
989
990 Ok(())
991 }
992
993 /// Paint an image into the scene for the current frame at the current z-index.
994 pub fn paint_image(
995 &mut self,
996 bounds: Bounds<Pixels>,
997 corner_radii: Corners<Pixels>,
998 data: Arc<ImageData>,
999 grayscale: bool,
1000 ) -> Result<()> {
1001 let scale_factor = self.scale_factor();
1002 let bounds = bounds.scale(scale_factor);
1003 let params = RenderImageParams { image_id: data.id };
1004
1005 let tile = self
1006 .window
1007 .sprite_atlas
1008 .get_or_insert_with(¶ms.clone().into(), &mut || {
1009 Ok((data.size(), Cow::Borrowed(data.as_bytes())))
1010 })?;
1011 let content_mask = self.content_mask().scale(scale_factor);
1012 let corner_radii = corner_radii.scale(scale_factor);
1013
1014 let window = &mut *self.window;
1015 window.current_frame.scene_builder.insert(
1016 &window.current_frame.z_index_stack,
1017 PolychromeSprite {
1018 order: 0,
1019 bounds,
1020 content_mask,
1021 corner_radii,
1022 tile,
1023 grayscale,
1024 },
1025 );
1026 Ok(())
1027 }
1028
1029 /// Draw pixels to the display for this window based on the contents of its scene.
1030 pub(crate) fn draw(&mut self) {
1031 let root_view = self.window.root_view.take().unwrap();
1032
1033 self.start_frame();
1034
1035 self.stack(0, |cx| {
1036 let available_space = cx.window.content_size.map(Into::into);
1037 root_view.draw(available_space, cx);
1038 });
1039
1040 if let Some(active_drag) = self.app.active_drag.take() {
1041 self.stack(1, |cx| {
1042 let offset = cx.mouse_position() - active_drag.cursor_offset;
1043 cx.with_element_offset(Some(offset), |cx| {
1044 let available_space =
1045 size(AvailableSpace::MinContent, AvailableSpace::MinContent);
1046 active_drag.view.draw(available_space, cx);
1047 cx.active_drag = Some(active_drag);
1048 });
1049 });
1050 } else if let Some(active_tooltip) = self.app.active_tooltip.take() {
1051 self.stack(1, |cx| {
1052 cx.with_element_offset(Some(active_tooltip.cursor_offset), |cx| {
1053 let available_space =
1054 size(AvailableSpace::MinContent, AvailableSpace::MinContent);
1055 active_tooltip.view.draw(available_space, cx);
1056 });
1057 });
1058 }
1059
1060 self.window.root_view = Some(root_view);
1061 let scene = self.window.current_frame.scene_builder.build();
1062
1063 self.window.platform_window.draw(scene);
1064 let cursor_style = self
1065 .window
1066 .requested_cursor_style
1067 .take()
1068 .unwrap_or(CursorStyle::Arrow);
1069 self.platform.set_cursor_style(cursor_style);
1070
1071 self.window.dirty = false;
1072 }
1073
1074 pub(crate) fn dispatch_stack(&mut self) -> Vec<KeyDispatchStackFrame> {
1075 let root_view = self.window.root_view.take().unwrap();
1076 let window = &mut *self.window;
1077 let mut spare_frame = Frame::default();
1078 mem::swap(&mut spare_frame, &mut window.previous_frame);
1079
1080 self.start_frame();
1081
1082 root_view.draw_dispatch_stack(self);
1083
1084 let window = &mut *self.window;
1085 // restore the old values of current and previous frame,
1086 // putting the new frame into spare_frame.
1087 mem::swap(&mut window.current_frame, &mut window.previous_frame);
1088 mem::swap(&mut spare_frame, &mut window.previous_frame);
1089 self.window.root_view = Some(root_view);
1090
1091 spare_frame.key_dispatch_stack
1092 }
1093
1094 /// Rotate the current frame and the previous frame, then clear the current frame.
1095 /// We repopulate all state in the current frame during each paint.
1096 fn start_frame(&mut self) {
1097 self.text_system().start_frame();
1098
1099 let window = &mut *self.window;
1100 mem::swap(&mut window.previous_frame, &mut window.current_frame);
1101 let frame = &mut window.current_frame;
1102 frame.element_states.clear();
1103 frame.key_matchers.clear();
1104 frame.mouse_listeners.values_mut().for_each(Vec::clear);
1105 frame.focus_listeners.clear();
1106 frame.key_dispatch_stack.clear();
1107 frame.focus_parents_by_child.clear();
1108 frame.freeze_key_dispatch_stack = false;
1109 }
1110
1111 /// Dispatch a mouse or keyboard event on the window.
1112 pub fn dispatch_event(&mut self, event: InputEvent) -> bool {
1113 // Handlers may set this to false by calling `stop_propagation`
1114 self.app.propagate_event = true;
1115 self.window.default_prevented = false;
1116
1117 let event = match event {
1118 // Track the mouse position with our own state, since accessing the platform
1119 // API for the mouse position can only occur on the main thread.
1120 InputEvent::MouseMove(mouse_move) => {
1121 self.window.mouse_position = mouse_move.position;
1122 InputEvent::MouseMove(mouse_move)
1123 }
1124 // Translate dragging and dropping of external files from the operating system
1125 // to internal drag and drop events.
1126 InputEvent::FileDrop(file_drop) => match file_drop {
1127 FileDropEvent::Entered { position, files } => {
1128 self.window.mouse_position = position;
1129 if self.active_drag.is_none() {
1130 self.active_drag = Some(AnyDrag {
1131 view: self.build_view(|_| files).into(),
1132 cursor_offset: position,
1133 });
1134 }
1135 InputEvent::MouseDown(MouseDownEvent {
1136 position,
1137 button: MouseButton::Left,
1138 click_count: 1,
1139 modifiers: Modifiers::default(),
1140 })
1141 }
1142 FileDropEvent::Pending { position } => {
1143 self.window.mouse_position = position;
1144 InputEvent::MouseMove(MouseMoveEvent {
1145 position,
1146 pressed_button: Some(MouseButton::Left),
1147 modifiers: Modifiers::default(),
1148 })
1149 }
1150 FileDropEvent::Submit { position } => {
1151 self.window.mouse_position = position;
1152 InputEvent::MouseUp(MouseUpEvent {
1153 button: MouseButton::Left,
1154 position,
1155 modifiers: Modifiers::default(),
1156 click_count: 1,
1157 })
1158 }
1159 FileDropEvent::Exited => InputEvent::MouseUp(MouseUpEvent {
1160 button: MouseButton::Left,
1161 position: Point::default(),
1162 modifiers: Modifiers::default(),
1163 click_count: 1,
1164 }),
1165 },
1166 _ => event,
1167 };
1168
1169 if let Some(any_mouse_event) = event.mouse_event() {
1170 if let Some(mut handlers) = self
1171 .window
1172 .current_frame
1173 .mouse_listeners
1174 .remove(&any_mouse_event.type_id())
1175 {
1176 // Because handlers may add other handlers, we sort every time.
1177 handlers.sort_by(|(a, _), (b, _)| a.cmp(b));
1178
1179 // Capture phase, events bubble from back to front. Handlers for this phase are used for
1180 // special purposes, such as detecting events outside of a given Bounds.
1181 for (_, handler) in &mut handlers {
1182 handler(any_mouse_event, DispatchPhase::Capture, self);
1183 if !self.app.propagate_event {
1184 break;
1185 }
1186 }
1187
1188 // Bubble phase, where most normal handlers do their work.
1189 if self.app.propagate_event {
1190 for (_, handler) in handlers.iter_mut().rev() {
1191 handler(any_mouse_event, DispatchPhase::Bubble, self);
1192 if !self.app.propagate_event {
1193 break;
1194 }
1195 }
1196 }
1197
1198 if self.app.propagate_event
1199 && any_mouse_event.downcast_ref::<MouseUpEvent>().is_some()
1200 {
1201 self.active_drag = None;
1202 }
1203
1204 // Just in case any handlers added new handlers, which is weird, but possible.
1205 handlers.extend(
1206 self.window
1207 .current_frame
1208 .mouse_listeners
1209 .get_mut(&any_mouse_event.type_id())
1210 .into_iter()
1211 .flat_map(|handlers| handlers.drain(..)),
1212 );
1213 self.window
1214 .current_frame
1215 .mouse_listeners
1216 .insert(any_mouse_event.type_id(), handlers);
1217 }
1218 } else if let Some(any_key_event) = event.keyboard_event() {
1219 let key_dispatch_stack = mem::take(&mut self.window.current_frame.key_dispatch_stack);
1220 let key_event_type = any_key_event.type_id();
1221 let mut context_stack = SmallVec::<[&DispatchContext; 16]>::new();
1222
1223 for (ix, frame) in key_dispatch_stack.iter().enumerate() {
1224 match frame {
1225 KeyDispatchStackFrame::Listener {
1226 event_type,
1227 listener,
1228 } => {
1229 if key_event_type == *event_type {
1230 if let Some(action) = listener(
1231 any_key_event,
1232 &context_stack,
1233 DispatchPhase::Capture,
1234 self,
1235 ) {
1236 self.dispatch_action_internal(action, &key_dispatch_stack[..ix]);
1237 }
1238 if !self.app.propagate_event {
1239 break;
1240 }
1241 }
1242 }
1243 KeyDispatchStackFrame::Context(context) => {
1244 context_stack.push(&context);
1245 }
1246 }
1247 }
1248
1249 if self.app.propagate_event {
1250 for (ix, frame) in key_dispatch_stack.iter().enumerate().rev() {
1251 match frame {
1252 KeyDispatchStackFrame::Listener {
1253 event_type,
1254 listener,
1255 } => {
1256 if key_event_type == *event_type {
1257 if let Some(action) = listener(
1258 any_key_event,
1259 &context_stack,
1260 DispatchPhase::Bubble,
1261 self,
1262 ) {
1263 self.dispatch_action_internal(
1264 action,
1265 &key_dispatch_stack[..ix],
1266 );
1267 }
1268
1269 if !self.app.propagate_event {
1270 break;
1271 }
1272 }
1273 }
1274 KeyDispatchStackFrame::Context(_) => {
1275 context_stack.pop();
1276 }
1277 }
1278 }
1279 }
1280
1281 drop(context_stack);
1282 self.window.current_frame.key_dispatch_stack = key_dispatch_stack;
1283 }
1284
1285 !self.app.propagate_event
1286 }
1287
1288 /// Attempt to map a keystroke to an action based on the keymap.
1289 pub fn match_keystroke(
1290 &mut self,
1291 element_id: &GlobalElementId,
1292 keystroke: &Keystroke,
1293 context_stack: &[&DispatchContext],
1294 ) -> KeyMatch {
1295 let key_match = self
1296 .window
1297 .current_frame
1298 .key_matchers
1299 .get_mut(element_id)
1300 .unwrap()
1301 .match_keystroke(keystroke, context_stack);
1302
1303 if key_match.is_some() {
1304 for matcher in self.window.current_frame.key_matchers.values_mut() {
1305 matcher.clear_pending();
1306 }
1307 }
1308
1309 key_match
1310 }
1311
1312 /// Register the given handler to be invoked whenever the global of the given type
1313 /// is updated.
1314 pub fn observe_global<G: 'static>(
1315 &mut self,
1316 f: impl Fn(&mut WindowContext<'_>) + 'static,
1317 ) -> Subscription {
1318 let window_handle = self.window.handle;
1319 self.global_observers.insert(
1320 TypeId::of::<G>(),
1321 Box::new(move |cx| window_handle.update(cx, |_, cx| f(cx)).is_ok()),
1322 )
1323 }
1324
1325 pub fn activate_window(&self) {
1326 self.window.platform_window.activate();
1327 }
1328
1329 pub fn prompt(
1330 &self,
1331 level: PromptLevel,
1332 msg: &str,
1333 answers: &[&str],
1334 ) -> oneshot::Receiver<usize> {
1335 self.window.platform_window.prompt(level, msg, answers)
1336 }
1337
1338 pub fn available_actions(&self) -> impl Iterator<Item = Box<dyn Action>> + '_ {
1339 let key_dispatch_stack = &self.window.previous_frame.key_dispatch_stack;
1340 key_dispatch_stack.iter().filter_map(|frame| {
1341 match frame {
1342 // todo!factor out a KeyDispatchStackFrame::Action
1343 KeyDispatchStackFrame::Listener {
1344 event_type,
1345 listener: _,
1346 } => {
1347 match build_action_from_type(event_type) {
1348 Ok(action) => Some(action),
1349 Err(err) => {
1350 dbg!(err);
1351 None
1352 } // we'll hit his if TypeId == KeyDown
1353 }
1354 }
1355 KeyDispatchStackFrame::Context(_) => None,
1356 }
1357 })
1358 }
1359
1360 pub(crate) fn dispatch_action_internal(
1361 &mut self,
1362 action: Box<dyn Action>,
1363 dispatch_stack: &[KeyDispatchStackFrame],
1364 ) {
1365 let action_type = action.as_any().type_id();
1366
1367 if let Some(mut global_listeners) = self.app.global_action_listeners.remove(&action_type) {
1368 for listener in &global_listeners {
1369 listener(action.as_ref(), DispatchPhase::Capture, self);
1370 if !self.app.propagate_event {
1371 break;
1372 }
1373 }
1374 global_listeners.extend(
1375 self.global_action_listeners
1376 .remove(&action_type)
1377 .unwrap_or_default(),
1378 );
1379 self.global_action_listeners
1380 .insert(action_type, global_listeners);
1381 }
1382
1383 if self.app.propagate_event {
1384 for stack_frame in dispatch_stack {
1385 if let KeyDispatchStackFrame::Listener {
1386 event_type,
1387 listener,
1388 } = stack_frame
1389 {
1390 if action_type == *event_type {
1391 listener(action.as_any(), &[], DispatchPhase::Capture, self);
1392 if !self.app.propagate_event {
1393 break;
1394 }
1395 }
1396 }
1397 }
1398 }
1399
1400 if self.app.propagate_event {
1401 for stack_frame in dispatch_stack.iter().rev() {
1402 if let KeyDispatchStackFrame::Listener {
1403 event_type,
1404 listener,
1405 } = stack_frame
1406 {
1407 if action_type == *event_type {
1408 self.app.propagate_event = false;
1409 listener(action.as_any(), &[], DispatchPhase::Bubble, self);
1410 if !self.app.propagate_event {
1411 break;
1412 }
1413 }
1414 }
1415 }
1416 }
1417
1418 if self.app.propagate_event {
1419 if let Some(mut global_listeners) =
1420 self.app.global_action_listeners.remove(&action_type)
1421 {
1422 for listener in global_listeners.iter().rev() {
1423 self.app.propagate_event = false;
1424 listener(action.as_ref(), DispatchPhase::Bubble, self);
1425 if !self.app.propagate_event {
1426 break;
1427 }
1428 }
1429 global_listeners.extend(
1430 self.global_action_listeners
1431 .remove(&action_type)
1432 .unwrap_or_default(),
1433 );
1434 self.global_action_listeners
1435 .insert(action_type, global_listeners);
1436 }
1437 }
1438 }
1439}
1440
1441impl Context for WindowContext<'_> {
1442 type Result<T> = T;
1443
1444 fn build_model<T>(
1445 &mut self,
1446 build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
1447 ) -> Model<T>
1448 where
1449 T: 'static,
1450 {
1451 let slot = self.app.entities.reserve();
1452 let model = build_model(&mut ModelContext::new(&mut *self.app, slot.downgrade()));
1453 self.entities.insert(slot, model)
1454 }
1455
1456 fn update_model<T: 'static, R>(
1457 &mut self,
1458 model: &Model<T>,
1459 update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
1460 ) -> R {
1461 let mut entity = self.entities.lease(model);
1462 let result = update(
1463 &mut *entity,
1464 &mut ModelContext::new(&mut *self.app, model.downgrade()),
1465 );
1466 self.entities.end_lease(entity);
1467 result
1468 }
1469
1470 fn update_window<T, F>(&mut self, window: AnyWindowHandle, update: F) -> Result<T>
1471 where
1472 F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
1473 {
1474 if window == self.window.handle {
1475 let root_view = self.window.root_view.clone().unwrap();
1476 Ok(update(root_view, self))
1477 } else {
1478 window.update(self.app, update)
1479 }
1480 }
1481
1482 fn read_model<T, R>(
1483 &self,
1484 handle: &Model<T>,
1485 read: impl FnOnce(&T, &AppContext) -> R,
1486 ) -> Self::Result<R>
1487 where
1488 T: 'static,
1489 {
1490 let entity = self.entities.read(handle);
1491 read(&*entity, &*self.app)
1492 }
1493}
1494
1495impl VisualContext for WindowContext<'_> {
1496 fn build_view<V>(
1497 &mut self,
1498 build_view_state: impl FnOnce(&mut ViewContext<'_, V>) -> V,
1499 ) -> Self::Result<View<V>>
1500 where
1501 V: 'static + Render,
1502 {
1503 let slot = self.app.entities.reserve();
1504 let view = View {
1505 model: slot.clone(),
1506 };
1507 let mut cx = ViewContext::new(&mut *self.app, &mut *self.window, &view);
1508 let entity = build_view_state(&mut cx);
1509 cx.entities.insert(slot, entity);
1510
1511 cx.new_view_observers
1512 .clone()
1513 .retain(&TypeId::of::<V>(), |observer| {
1514 let any_view = AnyView::from(view.clone());
1515 (observer)(any_view, self);
1516 true
1517 });
1518
1519 view
1520 }
1521
1522 /// Update the given view. Prefer calling `View::update` instead, which calls this method.
1523 fn update_view<T: 'static, R>(
1524 &mut self,
1525 view: &View<T>,
1526 update: impl FnOnce(&mut T, &mut ViewContext<'_, T>) -> R,
1527 ) -> Self::Result<R> {
1528 let mut lease = self.app.entities.lease(&view.model);
1529 let mut cx = ViewContext::new(&mut *self.app, &mut *self.window, &view);
1530 let result = update(&mut *lease, &mut cx);
1531 cx.app.entities.end_lease(lease);
1532 result
1533 }
1534
1535 fn replace_root_view<V>(
1536 &mut self,
1537 build_view: impl FnOnce(&mut ViewContext<'_, V>) -> V,
1538 ) -> Self::Result<View<V>>
1539 where
1540 V: Render,
1541 {
1542 let slot = self.app.entities.reserve();
1543 let view = View {
1544 model: slot.clone(),
1545 };
1546 let mut cx = ViewContext::new(&mut *self.app, &mut *self.window, &view);
1547 let entity = build_view(&mut cx);
1548 self.entities.insert(slot, entity);
1549 self.window.root_view = Some(view.clone().into());
1550 view
1551 }
1552}
1553
1554impl<'a> std::ops::Deref for WindowContext<'a> {
1555 type Target = AppContext;
1556
1557 fn deref(&self) -> &Self::Target {
1558 &self.app
1559 }
1560}
1561
1562impl<'a> std::ops::DerefMut for WindowContext<'a> {
1563 fn deref_mut(&mut self) -> &mut Self::Target {
1564 &mut self.app
1565 }
1566}
1567
1568impl<'a> Borrow<AppContext> for WindowContext<'a> {
1569 fn borrow(&self) -> &AppContext {
1570 &self.app
1571 }
1572}
1573
1574impl<'a> BorrowMut<AppContext> for WindowContext<'a> {
1575 fn borrow_mut(&mut self) -> &mut AppContext {
1576 &mut self.app
1577 }
1578}
1579
1580pub trait BorrowWindow: BorrowMut<Window> + BorrowMut<AppContext> {
1581 fn app_mut(&mut self) -> &mut AppContext {
1582 self.borrow_mut()
1583 }
1584
1585 fn window(&self) -> &Window {
1586 self.borrow()
1587 }
1588
1589 fn window_mut(&mut self) -> &mut Window {
1590 self.borrow_mut()
1591 }
1592
1593 /// Pushes the given element id onto the global stack and invokes the given closure
1594 /// with a `GlobalElementId`, which disambiguates the given id in the context of its ancestor
1595 /// ids. Because elements are discarded and recreated on each frame, the `GlobalElementId` is
1596 /// used to associate state with identified elements across separate frames.
1597 fn with_element_id<R>(
1598 &mut self,
1599 id: impl Into<ElementId>,
1600 f: impl FnOnce(GlobalElementId, &mut Self) -> R,
1601 ) -> R {
1602 let keymap = self.app_mut().keymap.clone();
1603 let window = self.window_mut();
1604 window.element_id_stack.push(id.into());
1605 let global_id = window.element_id_stack.clone();
1606
1607 if window.current_frame.key_matchers.get(&global_id).is_none() {
1608 window.current_frame.key_matchers.insert(
1609 global_id.clone(),
1610 window
1611 .previous_frame
1612 .key_matchers
1613 .remove(&global_id)
1614 .unwrap_or_else(|| KeyMatcher::new(keymap)),
1615 );
1616 }
1617
1618 let result = f(global_id, self);
1619 let window: &mut Window = self.borrow_mut();
1620 window.element_id_stack.pop();
1621 result
1622 }
1623
1624 /// Invoke the given function with the given content mask after intersecting it
1625 /// with the current mask.
1626 fn with_content_mask<R>(
1627 &mut self,
1628 mask: ContentMask<Pixels>,
1629 f: impl FnOnce(&mut Self) -> R,
1630 ) -> R {
1631 let mask = mask.intersect(&self.content_mask());
1632 self.window_mut()
1633 .current_frame
1634 .content_mask_stack
1635 .push(mask);
1636 let result = f(self);
1637 self.window_mut().current_frame.content_mask_stack.pop();
1638 result
1639 }
1640
1641 /// Update the global element offset based on the given offset. This is used to implement
1642 /// scrolling and position drag handles.
1643 fn with_element_offset<R>(
1644 &mut self,
1645 offset: Option<Point<Pixels>>,
1646 f: impl FnOnce(&mut Self) -> R,
1647 ) -> R {
1648 let Some(offset) = offset else {
1649 return f(self);
1650 };
1651
1652 let offset = self.element_offset() + offset;
1653 self.window_mut()
1654 .current_frame
1655 .element_offset_stack
1656 .push(offset);
1657 let result = f(self);
1658 self.window_mut().current_frame.element_offset_stack.pop();
1659 result
1660 }
1661
1662 /// Obtain the current element offset.
1663 fn element_offset(&self) -> Point<Pixels> {
1664 self.window()
1665 .current_frame
1666 .element_offset_stack
1667 .last()
1668 .copied()
1669 .unwrap_or_default()
1670 }
1671
1672 /// Update or intialize state for an element with the given id that lives across multiple
1673 /// frames. If an element with this id existed in the previous frame, its state will be passed
1674 /// to the given closure. The state returned by the closure will be stored so it can be referenced
1675 /// when drawing the next frame.
1676 fn with_element_state<S, R>(
1677 &mut self,
1678 id: ElementId,
1679 f: impl FnOnce(Option<S>, &mut Self) -> (R, S),
1680 ) -> R
1681 where
1682 S: 'static,
1683 {
1684 self.with_element_id(id, |global_id, cx| {
1685 if let Some(any) = cx
1686 .window_mut()
1687 .current_frame
1688 .element_states
1689 .remove(&global_id)
1690 .or_else(|| {
1691 cx.window_mut()
1692 .previous_frame
1693 .element_states
1694 .remove(&global_id)
1695 })
1696 {
1697 // Using the extra inner option to avoid needing to reallocate a new box.
1698 let mut state_box = any
1699 .downcast::<Option<S>>()
1700 .expect("invalid element state type for id");
1701 let state = state_box
1702 .take()
1703 .expect("element state is already on the stack");
1704 let (result, state) = f(Some(state), cx);
1705 state_box.replace(state);
1706 cx.window_mut()
1707 .current_frame
1708 .element_states
1709 .insert(global_id, state_box);
1710 result
1711 } else {
1712 let (result, state) = f(None, cx);
1713 cx.window_mut()
1714 .current_frame
1715 .element_states
1716 .insert(global_id, Box::new(Some(state)));
1717 result
1718 }
1719 })
1720 }
1721
1722 /// Like `with_element_state`, but for situations where the element_id is optional. If the
1723 /// id is `None`, no state will be retrieved or stored.
1724 fn with_optional_element_state<S, R>(
1725 &mut self,
1726 element_id: Option<ElementId>,
1727 f: impl FnOnce(Option<S>, &mut Self) -> (R, S),
1728 ) -> R
1729 where
1730 S: 'static,
1731 {
1732 if let Some(element_id) = element_id {
1733 self.with_element_state(element_id, f)
1734 } else {
1735 f(None, self).0
1736 }
1737 }
1738
1739 /// Obtain the current content mask.
1740 fn content_mask(&self) -> ContentMask<Pixels> {
1741 self.window()
1742 .current_frame
1743 .content_mask_stack
1744 .last()
1745 .cloned()
1746 .unwrap_or_else(|| ContentMask {
1747 bounds: Bounds {
1748 origin: Point::default(),
1749 size: self.window().content_size,
1750 },
1751 })
1752 }
1753
1754 /// The size of an em for the base font of the application. Adjusting this value allows the
1755 /// UI to scale, just like zooming a web page.
1756 fn rem_size(&self) -> Pixels {
1757 self.window().rem_size
1758 }
1759}
1760
1761impl Borrow<Window> for WindowContext<'_> {
1762 fn borrow(&self) -> &Window {
1763 &self.window
1764 }
1765}
1766
1767impl BorrowMut<Window> for WindowContext<'_> {
1768 fn borrow_mut(&mut self) -> &mut Window {
1769 &mut self.window
1770 }
1771}
1772
1773impl<T> BorrowWindow for T where T: BorrowMut<AppContext> + BorrowMut<Window> {}
1774
1775pub struct ViewContext<'a, V> {
1776 window_cx: WindowContext<'a>,
1777 view: &'a View<V>,
1778}
1779
1780impl<V> Borrow<AppContext> for ViewContext<'_, V> {
1781 fn borrow(&self) -> &AppContext {
1782 &*self.window_cx.app
1783 }
1784}
1785
1786impl<V> BorrowMut<AppContext> for ViewContext<'_, V> {
1787 fn borrow_mut(&mut self) -> &mut AppContext {
1788 &mut *self.window_cx.app
1789 }
1790}
1791
1792impl<V> Borrow<Window> for ViewContext<'_, V> {
1793 fn borrow(&self) -> &Window {
1794 &*self.window_cx.window
1795 }
1796}
1797
1798impl<V> BorrowMut<Window> for ViewContext<'_, V> {
1799 fn borrow_mut(&mut self) -> &mut Window {
1800 &mut *self.window_cx.window
1801 }
1802}
1803
1804impl<'a, V: 'static> ViewContext<'a, V> {
1805 pub(crate) fn new(app: &'a mut AppContext, window: &'a mut Window, view: &'a View<V>) -> Self {
1806 Self {
1807 window_cx: WindowContext::new(app, window),
1808 view,
1809 }
1810 }
1811
1812 // todo!("change this to return a reference");
1813 pub fn view(&self) -> View<V> {
1814 self.view.clone()
1815 }
1816
1817 pub fn model(&self) -> Model<V> {
1818 self.view.model.clone()
1819 }
1820
1821 /// Access the underlying window context.
1822 pub fn window_context(&mut self) -> &mut WindowContext<'a> {
1823 &mut self.window_cx
1824 }
1825
1826 pub fn with_z_index<R>(&mut self, z_index: u32, f: impl FnOnce(&mut Self) -> R) -> R {
1827 self.window.current_frame.z_index_stack.push(z_index);
1828 let result = f(self);
1829 self.window.current_frame.z_index_stack.pop();
1830 result
1831 }
1832
1833 pub fn on_next_frame(&mut self, f: impl FnOnce(&mut V, &mut ViewContext<V>) + 'static)
1834 where
1835 V: 'static,
1836 {
1837 let view = self.view();
1838 self.window_cx.on_next_frame(move |cx| view.update(cx, f));
1839 }
1840
1841 /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
1842 /// that are currently on the stack to be returned to the app.
1843 pub fn defer(&mut self, f: impl FnOnce(&mut V, &mut ViewContext<V>) + 'static) {
1844 let view = self.view().downgrade();
1845 self.window_cx.defer(move |cx| {
1846 view.update(cx, f).ok();
1847 });
1848 }
1849
1850 pub fn observe<V2, E>(
1851 &mut self,
1852 entity: &E,
1853 mut on_notify: impl FnMut(&mut V, E, &mut ViewContext<'_, V>) + 'static,
1854 ) -> Subscription
1855 where
1856 V2: 'static,
1857 V: 'static,
1858 E: Entity<V2>,
1859 {
1860 let view = self.view().downgrade();
1861 let entity_id = entity.entity_id();
1862 let entity = entity.downgrade();
1863 let window_handle = self.window.handle;
1864 self.app.observers.insert(
1865 entity_id,
1866 Box::new(move |cx| {
1867 window_handle
1868 .update(cx, |_, cx| {
1869 if let Some(handle) = E::upgrade_from(&entity) {
1870 view.update(cx, |this, cx| on_notify(this, handle, cx))
1871 .is_ok()
1872 } else {
1873 false
1874 }
1875 })
1876 .unwrap_or(false)
1877 }),
1878 )
1879 }
1880
1881 pub fn subscribe<V2, E, Evt>(
1882 &mut self,
1883 entity: &E,
1884 mut on_event: impl FnMut(&mut V, E, &Evt, &mut ViewContext<'_, V>) + 'static,
1885 ) -> Subscription
1886 where
1887 V2: EventEmitter<Evt>,
1888 E: Entity<V2>,
1889 Evt: 'static,
1890 {
1891 let view = self.view().downgrade();
1892 let entity_id = entity.entity_id();
1893 let handle = entity.downgrade();
1894 let window_handle = self.window.handle;
1895 self.app.event_listeners.insert(
1896 entity_id,
1897 (
1898 TypeId::of::<Evt>(),
1899 Box::new(move |event, cx| {
1900 window_handle
1901 .update(cx, |_, cx| {
1902 if let Some(handle) = E::upgrade_from(&handle) {
1903 let event = event.downcast_ref().expect("invalid event type");
1904 view.update(cx, |this, cx| on_event(this, handle, event, cx))
1905 .is_ok()
1906 } else {
1907 false
1908 }
1909 })
1910 .unwrap_or(false)
1911 }),
1912 ),
1913 )
1914 }
1915
1916 pub fn on_release(
1917 &mut self,
1918 on_release: impl FnOnce(&mut V, &mut WindowContext) + 'static,
1919 ) -> Subscription {
1920 let window_handle = self.window.handle;
1921 self.app.release_listeners.insert(
1922 self.view.model.entity_id,
1923 Box::new(move |this, cx| {
1924 let this = this.downcast_mut().expect("invalid entity type");
1925 let _ = window_handle.update(cx, |_, cx| on_release(this, cx));
1926 }),
1927 )
1928 }
1929
1930 pub fn observe_release<V2, E>(
1931 &mut self,
1932 entity: &E,
1933 mut on_release: impl FnMut(&mut V, &mut V2, &mut ViewContext<'_, V>) + 'static,
1934 ) -> Subscription
1935 where
1936 V: 'static,
1937 V2: 'static,
1938 E: Entity<V2>,
1939 {
1940 let view = self.view().downgrade();
1941 let entity_id = entity.entity_id();
1942 let window_handle = self.window.handle;
1943 self.app.release_listeners.insert(
1944 entity_id,
1945 Box::new(move |entity, cx| {
1946 let entity = entity.downcast_mut().expect("invalid entity type");
1947 let _ = window_handle.update(cx, |_, cx| {
1948 view.update(cx, |this, cx| on_release(this, entity, cx))
1949 });
1950 }),
1951 )
1952 }
1953
1954 pub fn notify(&mut self) {
1955 self.window_cx.notify();
1956 self.window_cx.app.push_effect(Effect::Notify {
1957 emitter: self.view.model.entity_id,
1958 });
1959 }
1960
1961 pub fn observe_window_bounds(
1962 &mut self,
1963 mut callback: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
1964 ) -> Subscription {
1965 let view = self.view.downgrade();
1966 self.window.bounds_observers.insert(
1967 (),
1968 Box::new(move |cx| view.update(cx, |view, cx| callback(view, cx)).is_ok()),
1969 )
1970 }
1971
1972 pub fn observe_window_activation(
1973 &mut self,
1974 mut callback: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
1975 ) -> Subscription {
1976 let view = self.view.downgrade();
1977 self.window.activation_observers.insert(
1978 (),
1979 Box::new(move |cx| view.update(cx, |view, cx| callback(view, cx)).is_ok()),
1980 )
1981 }
1982
1983 /// Register a listener to be called when the given focus handle receives focus.
1984 /// Unlike [on_focus_changed], returns a subscription and persists until the subscription
1985 /// is dropped.
1986 pub fn on_focus(
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.focused.as_ref().map(|focused| focused.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 receives focus.
2007 /// Unlike [on_focus_changed], returns a subscription and persists until the subscription
2008 /// is dropped.
2009 pub fn on_focus_in(
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 .focused
2022 .as_ref()
2023 .map_or(false, |focused| focus_id.contains(focused.id, cx))
2024 {
2025 listener(view, cx)
2026 }
2027 })
2028 .is_ok()
2029 }),
2030 )
2031 }
2032
2033 /// Register a listener to be called when the given focus handle loses focus.
2034 /// Unlike [on_focus_changed], returns a subscription and persists until the subscription
2035 /// is dropped.
2036 pub fn on_blur(
2037 &mut self,
2038 handle: &FocusHandle,
2039 mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2040 ) -> Subscription {
2041 let view = self.view.downgrade();
2042 let focus_id = handle.id;
2043 self.window.focus_listeners.insert(
2044 (),
2045 Box::new(move |event, cx| {
2046 view.update(cx, |view, cx| {
2047 if event.blurred.as_ref().map(|blurred| blurred.id) == Some(focus_id) {
2048 listener(view, cx)
2049 }
2050 })
2051 .is_ok()
2052 }),
2053 )
2054 }
2055
2056 /// Register a listener to be called when the given focus handle or one of its descendants loses focus.
2057 /// Unlike [on_focus_changed], returns a subscription and persists until the subscription
2058 /// is dropped.
2059 pub fn on_focus_out(
2060 &mut self,
2061 handle: &FocusHandle,
2062 mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2063 ) -> Subscription {
2064 let view = self.view.downgrade();
2065 let focus_id = handle.id;
2066 self.window.focus_listeners.insert(
2067 (),
2068 Box::new(move |event, cx| {
2069 view.update(cx, |view, cx| {
2070 if event
2071 .blurred
2072 .as_ref()
2073 .map_or(false, |blurred| focus_id.contains(blurred.id, cx))
2074 {
2075 listener(view, cx)
2076 }
2077 })
2078 .is_ok()
2079 }),
2080 )
2081 }
2082
2083 /// Register a focus listener for the current frame only. It will be cleared
2084 /// on the next frame render. You should use this method only from within elements,
2085 /// and we may want to enforce that better via a different context type.
2086 // todo!() Move this to `FrameContext` to emphasize its individuality?
2087 pub fn on_focus_changed(
2088 &mut self,
2089 listener: impl Fn(&mut V, &FocusEvent, &mut ViewContext<V>) + 'static,
2090 ) {
2091 let handle = self.view().downgrade();
2092 self.window
2093 .current_frame
2094 .focus_listeners
2095 .push(Box::new(move |event, cx| {
2096 handle
2097 .update(cx, |view, cx| listener(view, event, cx))
2098 .log_err();
2099 }));
2100 }
2101
2102 pub fn with_key_listeners<R>(
2103 &mut self,
2104 key_listeners: impl IntoIterator<Item = (TypeId, KeyListener<V>)>,
2105 f: impl FnOnce(&mut Self) -> R,
2106 ) -> R {
2107 let old_stack_len = self.window.current_frame.key_dispatch_stack.len();
2108 if !self.window.current_frame.freeze_key_dispatch_stack {
2109 for (event_type, listener) in key_listeners {
2110 let handle = self.view().downgrade();
2111 let listener = Box::new(
2112 move |event: &dyn Any,
2113 context_stack: &[&DispatchContext],
2114 phase: DispatchPhase,
2115 cx: &mut WindowContext<'_>| {
2116 handle
2117 .update(cx, |view, cx| {
2118 listener(view, event, context_stack, phase, cx)
2119 })
2120 .log_err()
2121 .flatten()
2122 },
2123 );
2124 self.window.current_frame.key_dispatch_stack.push(
2125 KeyDispatchStackFrame::Listener {
2126 event_type,
2127 listener,
2128 },
2129 );
2130 }
2131 }
2132
2133 let result = f(self);
2134
2135 if !self.window.current_frame.freeze_key_dispatch_stack {
2136 self.window
2137 .current_frame
2138 .key_dispatch_stack
2139 .truncate(old_stack_len);
2140 }
2141
2142 result
2143 }
2144
2145 pub fn with_key_dispatch_context<R>(
2146 &mut self,
2147 context: DispatchContext,
2148 f: impl FnOnce(&mut Self) -> R,
2149 ) -> R {
2150 if context.is_empty() {
2151 return f(self);
2152 }
2153
2154 if !self.window.current_frame.freeze_key_dispatch_stack {
2155 self.window
2156 .current_frame
2157 .key_dispatch_stack
2158 .push(KeyDispatchStackFrame::Context(context));
2159 }
2160
2161 let result = f(self);
2162
2163 if !self.window.previous_frame.freeze_key_dispatch_stack {
2164 self.window.previous_frame.key_dispatch_stack.pop();
2165 }
2166
2167 result
2168 }
2169
2170 pub fn with_focus<R>(
2171 &mut self,
2172 focus_handle: FocusHandle,
2173 f: impl FnOnce(&mut Self) -> R,
2174 ) -> R {
2175 if let Some(parent_focus_id) = self.window.current_frame.focus_stack.last().copied() {
2176 self.window
2177 .current_frame
2178 .focus_parents_by_child
2179 .insert(focus_handle.id, parent_focus_id);
2180 }
2181 self.window.current_frame.focus_stack.push(focus_handle.id);
2182
2183 if Some(focus_handle.id) == self.window.focus {
2184 self.window.current_frame.freeze_key_dispatch_stack = true;
2185 }
2186
2187 let result = f(self);
2188
2189 self.window.current_frame.focus_stack.pop();
2190 result
2191 }
2192
2193 pub fn spawn<Fut, R>(
2194 &mut self,
2195 f: impl FnOnce(WeakView<V>, AsyncWindowContext) -> Fut,
2196 ) -> Task<R>
2197 where
2198 R: 'static,
2199 Fut: Future<Output = R> + 'static,
2200 {
2201 let view = self.view().downgrade();
2202 self.window_cx.spawn(|cx| f(view, cx))
2203 }
2204
2205 pub fn update_global<G, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R
2206 where
2207 G: 'static,
2208 {
2209 let mut global = self.app.lease_global::<G>();
2210 let result = f(&mut global, self);
2211 self.app.end_global_lease(global);
2212 result
2213 }
2214
2215 pub fn observe_global<G: 'static>(
2216 &mut self,
2217 f: impl Fn(&mut V, &mut ViewContext<'_, V>) + 'static,
2218 ) -> Subscription {
2219 let window_handle = self.window.handle;
2220 let view = self.view().downgrade();
2221 self.global_observers.insert(
2222 TypeId::of::<G>(),
2223 Box::new(move |cx| {
2224 window_handle
2225 .update(cx, |_, cx| view.update(cx, |view, cx| f(view, cx)).is_ok())
2226 .unwrap_or(false)
2227 }),
2228 )
2229 }
2230
2231 pub fn on_mouse_event<Event: 'static>(
2232 &mut self,
2233 handler: impl Fn(&mut V, &Event, DispatchPhase, &mut ViewContext<V>) + 'static,
2234 ) {
2235 let handle = self.view();
2236 self.window_cx.on_mouse_event(move |event, phase, cx| {
2237 handle.update(cx, |view, cx| {
2238 handler(view, event, phase, cx);
2239 })
2240 });
2241 }
2242
2243 /// Set an input handler, such as [ElementInputHandler], which interfaces with the
2244 /// platform to receive textual input with proper integration with concerns such
2245 /// as IME interactions.
2246 pub fn handle_input(
2247 &mut self,
2248 focus_handle: &FocusHandle,
2249 input_handler: impl PlatformInputHandler,
2250 ) {
2251 if focus_handle.is_focused(self) {
2252 self.window
2253 .platform_window
2254 .set_input_handler(Box::new(input_handler));
2255 }
2256 }
2257}
2258
2259impl<V> ViewContext<'_, V> {
2260 pub fn emit<Evt>(&mut self, event: Evt)
2261 where
2262 Evt: 'static,
2263 V: EventEmitter<Evt>,
2264 {
2265 let emitter = self.view.model.entity_id;
2266 self.app.push_effect(Effect::Emit {
2267 emitter,
2268 event_type: TypeId::of::<Evt>(),
2269 event: Box::new(event),
2270 });
2271 }
2272}
2273
2274impl<V> Context for ViewContext<'_, V> {
2275 type Result<U> = U;
2276
2277 fn build_model<T: 'static>(
2278 &mut self,
2279 build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
2280 ) -> Model<T> {
2281 self.window_cx.build_model(build_model)
2282 }
2283
2284 fn update_model<T: 'static, R>(
2285 &mut self,
2286 model: &Model<T>,
2287 update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
2288 ) -> R {
2289 self.window_cx.update_model(model, update)
2290 }
2291
2292 fn update_window<T, F>(&mut self, window: AnyWindowHandle, update: F) -> Result<T>
2293 where
2294 F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
2295 {
2296 self.window_cx.update_window(window, update)
2297 }
2298
2299 fn read_model<T, R>(
2300 &self,
2301 handle: &Model<T>,
2302 read: impl FnOnce(&T, &AppContext) -> R,
2303 ) -> Self::Result<R>
2304 where
2305 T: 'static,
2306 {
2307 self.window_cx.read_model(handle, read)
2308 }
2309}
2310
2311impl<V: 'static> VisualContext for ViewContext<'_, V> {
2312 fn build_view<W: Render + 'static>(
2313 &mut self,
2314 build_view_state: impl FnOnce(&mut ViewContext<'_, W>) -> W,
2315 ) -> Self::Result<View<W>> {
2316 self.window_cx.build_view(build_view_state)
2317 }
2318
2319 fn update_view<V2: 'static, R>(
2320 &mut self,
2321 view: &View<V2>,
2322 update: impl FnOnce(&mut V2, &mut ViewContext<'_, V2>) -> R,
2323 ) -> Self::Result<R> {
2324 self.window_cx.update_view(view, update)
2325 }
2326
2327 fn replace_root_view<W>(
2328 &mut self,
2329 build_view: impl FnOnce(&mut ViewContext<'_, W>) -> W,
2330 ) -> Self::Result<View<W>>
2331 where
2332 W: Render,
2333 {
2334 self.window_cx.replace_root_view(build_view)
2335 }
2336}
2337
2338impl<'a, V> std::ops::Deref for ViewContext<'a, V> {
2339 type Target = WindowContext<'a>;
2340
2341 fn deref(&self) -> &Self::Target {
2342 &self.window_cx
2343 }
2344}
2345
2346impl<'a, V> std::ops::DerefMut for ViewContext<'a, V> {
2347 fn deref_mut(&mut self) -> &mut Self::Target {
2348 &mut self.window_cx
2349 }
2350}
2351
2352// #[derive(Clone, Copy, Eq, PartialEq, Hash)]
2353slotmap::new_key_type! { pub struct WindowId; }
2354
2355impl WindowId {
2356 pub fn as_u64(&self) -> u64 {
2357 self.0.as_ffi()
2358 }
2359}
2360
2361#[derive(Deref, DerefMut)]
2362pub struct WindowHandle<V> {
2363 #[deref]
2364 #[deref_mut]
2365 pub(crate) any_handle: AnyWindowHandle,
2366 state_type: PhantomData<V>,
2367}
2368
2369impl<V: 'static + Render> WindowHandle<V> {
2370 pub fn new(id: WindowId) -> Self {
2371 WindowHandle {
2372 any_handle: AnyWindowHandle {
2373 id,
2374 state_type: TypeId::of::<V>(),
2375 },
2376 state_type: PhantomData,
2377 }
2378 }
2379
2380 pub fn update<C, R>(
2381 self,
2382 cx: &mut C,
2383 update: impl FnOnce(&mut V, &mut ViewContext<'_, V>) -> R,
2384 ) -> Result<R>
2385 where
2386 C: Context,
2387 {
2388 cx.update_window(self.any_handle, |root_view, cx| {
2389 let view = root_view
2390 .downcast::<V>()
2391 .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
2392 Ok(cx.update_view(&view, update))
2393 })?
2394 }
2395}
2396
2397impl<V> Copy for WindowHandle<V> {}
2398
2399impl<V> Clone for WindowHandle<V> {
2400 fn clone(&self) -> Self {
2401 WindowHandle {
2402 any_handle: self.any_handle,
2403 state_type: PhantomData,
2404 }
2405 }
2406}
2407
2408impl<V> PartialEq for WindowHandle<V> {
2409 fn eq(&self, other: &Self) -> bool {
2410 self.any_handle == other.any_handle
2411 }
2412}
2413
2414impl<V> Eq for WindowHandle<V> {}
2415
2416impl<V> Hash for WindowHandle<V> {
2417 fn hash<H: Hasher>(&self, state: &mut H) {
2418 self.any_handle.hash(state);
2419 }
2420}
2421
2422impl<V: 'static> Into<AnyWindowHandle> for WindowHandle<V> {
2423 fn into(self) -> AnyWindowHandle {
2424 self.any_handle
2425 }
2426}
2427
2428#[derive(Copy, Clone, PartialEq, Eq, Hash)]
2429pub struct AnyWindowHandle {
2430 pub(crate) id: WindowId,
2431 state_type: TypeId,
2432}
2433
2434impl AnyWindowHandle {
2435 pub fn window_id(&self) -> WindowId {
2436 self.id
2437 }
2438
2439 pub fn downcast<T: 'static>(&self) -> Option<WindowHandle<T>> {
2440 if TypeId::of::<T>() == self.state_type {
2441 Some(WindowHandle {
2442 any_handle: *self,
2443 state_type: PhantomData,
2444 })
2445 } else {
2446 None
2447 }
2448 }
2449
2450 pub fn update<C, R>(
2451 self,
2452 cx: &mut C,
2453 update: impl FnOnce(AnyView, &mut WindowContext<'_>) -> R,
2454 ) -> Result<R>
2455 where
2456 C: Context,
2457 {
2458 cx.update_window(self, update)
2459 }
2460}
2461
2462#[cfg(any(test, feature = "test-support"))]
2463impl From<SmallVec<[u32; 16]>> for StackingOrder {
2464 fn from(small_vec: SmallVec<[u32; 16]>) -> Self {
2465 StackingOrder(small_vec)
2466 }
2467}
2468
2469#[derive(Clone, Debug, Eq, PartialEq, Hash)]
2470pub enum ElementId {
2471 View(EntityId),
2472 Number(usize),
2473 Name(SharedString),
2474 FocusHandle(FocusId),
2475}
2476
2477impl From<EntityId> for ElementId {
2478 fn from(id: EntityId) -> Self {
2479 ElementId::View(id)
2480 }
2481}
2482
2483impl From<usize> for ElementId {
2484 fn from(id: usize) -> Self {
2485 ElementId::Number(id)
2486 }
2487}
2488
2489impl From<i32> for ElementId {
2490 fn from(id: i32) -> Self {
2491 Self::Number(id as usize)
2492 }
2493}
2494
2495impl From<SharedString> for ElementId {
2496 fn from(name: SharedString) -> Self {
2497 ElementId::Name(name)
2498 }
2499}
2500
2501impl From<&'static str> for ElementId {
2502 fn from(name: &'static str) -> Self {
2503 ElementId::Name(name.into())
2504 }
2505}
2506
2507impl<'a> From<&'a FocusHandle> for ElementId {
2508 fn from(handle: &'a FocusHandle) -> Self {
2509 ElementId::FocusHandle(handle.id)
2510 }
2511}