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