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