1use crate::{
2 key_dispatch::DispatchActionListener, px, size, Action, AnyBox, AnyDrag, AnyView, AppContext,
3 AsyncWindowContext, AvailableSpace, Bounds, BoxShadow, Context, Corners, CursorStyle,
4 DevicePixels, DispatchNodeId, DispatchTree, DisplayId, Edges, Effect, Entity, EntityId,
5 EventEmitter, FileDropEvent, FocusEvent, FontId, GlobalElementId, GlyphId, Hsla, ImageData,
6 InputEvent, IsZero, KeyBinding, KeyContext, KeyDownEvent, LayoutId, Model, ModelContext,
7 Modifiers, MonochromeSprite, MouseButton, MouseDownEvent, MouseMoveEvent, MouseUpEvent, Path,
8 Pixels, PlatformAtlas, PlatformDisplay, PlatformInputHandler, PlatformWindow, Point,
9 PolychromeSprite, PromptLevel, Quad, Render, RenderGlyphParams, RenderImageParams,
10 RenderSvgParams, ScaledPixels, SceneBuilder, Shadow, SharedString, Size, Style, SubscriberSet,
11 Subscription, TaffyLayoutEngine, Task, Underline, UnderlineStyle, View, VisualContext,
12 WeakView, WindowBounds, WindowOptions, SUBPIXEL_VARIANTS,
13};
14use anyhow::{anyhow, Context as _, Result};
15use collections::HashMap;
16use derive_more::{Deref, DerefMut};
17use futures::{
18 channel::{mpsc, oneshot},
19 StreamExt,
20};
21use parking_lot::RwLock;
22use slotmap::SlotMap;
23use smallvec::SmallVec;
24use std::{
25 any::{Any, TypeId},
26 borrow::{Borrow, BorrowMut, Cow},
27 fmt::Debug,
28 future::Future,
29 hash::{Hash, Hasher},
30 marker::PhantomData,
31 mem,
32 rc::Rc,
33 sync::{
34 atomic::{AtomicUsize, Ordering::SeqCst},
35 Arc,
36 },
37};
38use util::ResultExt;
39
40/// A global stacking order, which is created by stacking successive z-index values.
41/// Each z-index will always be interpreted in the context of its parent z-index.
42#[derive(Deref, DerefMut, Ord, PartialOrd, Eq, PartialEq, Clone, Default)]
43pub(crate) struct StackingOrder(pub(crate) SmallVec<[u32; 16]>);
44
45/// Represents the two different phases when dispatching events.
46#[derive(Default, Copy, Clone, Debug, Eq, PartialEq)]
47pub enum DispatchPhase {
48 /// After the capture phase comes the bubble phase, in which mouse event listeners are
49 /// invoked front to back and keyboard event listeners are invoked from the focused element
50 /// to the root of the element tree. This is the phase you'll most commonly want to use when
51 /// registering event listeners.
52 #[default]
53 Bubble,
54 /// During the initial capture phase, mouse event listeners are invoked back to front, and keyboard
55 /// listeners are invoked from the root of the tree downward toward the focused element. This phase
56 /// is used for special purposes such as clearing the "pressed" state for click events. If
57 /// you stop event propagation during this phase, you need to know what you're doing. Handlers
58 /// outside of the immediate region may rely on detecting non-local events during this phase.
59 Capture,
60}
61
62type AnyObserver = Box<dyn FnMut(&mut WindowContext) -> bool + 'static>;
63type AnyMouseListener = Box<dyn FnMut(&dyn Any, DispatchPhase, &mut WindowContext) + 'static>;
64type AnyFocusListener = Box<dyn Fn(&FocusEvent, &mut WindowContext) + 'static>;
65type AnyWindowFocusListener = Box<dyn FnMut(&FocusEvent, &mut WindowContext) -> bool + 'static>;
66
67slotmap::new_key_type! { pub struct FocusId; }
68
69impl FocusId {
70 /// Obtains whether the element associated with this handle is currently focused.
71 pub fn is_focused(&self, cx: &WindowContext) -> bool {
72 cx.window.focus == Some(*self)
73 }
74
75 /// Obtains whether the element associated with this handle contains the focused
76 /// element or is itself focused.
77 pub fn contains_focused(&self, cx: &WindowContext) -> bool {
78 cx.focused()
79 .map_or(false, |focused| self.contains(focused.id, cx))
80 }
81
82 /// Obtains whether the element associated with this handle is contained within the
83 /// focused element or is itself focused.
84 pub fn within_focused(&self, cx: &WindowContext) -> bool {
85 let focused = cx.focused();
86 focused.map_or(false, |focused| focused.id.contains(*self, cx))
87 }
88
89 /// Obtains whether this handle contains the given handle in the most recently rendered frame.
90 pub(crate) fn contains(&self, other: Self, cx: &WindowContext) -> bool {
91 cx.window
92 .current_frame
93 .dispatch_tree
94 .focus_contains(*self, other)
95 }
96}
97
98/// A handle which can be used to track and manipulate the focused element in a window.
99pub struct FocusHandle {
100 pub(crate) id: FocusId,
101 handles: Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>,
102}
103
104impl std::fmt::Debug for FocusHandle {
105 fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
106 f.write_fmt(format_args!("FocusHandle({:?})", self.id))
107 }
108}
109
110impl FocusHandle {
111 pub(crate) fn new(handles: &Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>) -> Self {
112 let id = handles.write().insert(AtomicUsize::new(1));
113 Self {
114 id,
115 handles: handles.clone(),
116 }
117 }
118
119 pub(crate) fn for_id(
120 id: FocusId,
121 handles: &Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>,
122 ) -> Option<Self> {
123 let lock = handles.read();
124 let ref_count = lock.get(id)?;
125 if ref_count.load(SeqCst) == 0 {
126 None
127 } else {
128 ref_count.fetch_add(1, SeqCst);
129 Some(Self {
130 id,
131 handles: handles.clone(),
132 })
133 }
134 }
135
136 /// Moves the focus to the element associated with this handle.
137 pub fn focus(&self, cx: &mut WindowContext) {
138 cx.focus(self)
139 }
140
141 /// Obtains whether the element associated with this handle is currently focused.
142 pub fn is_focused(&self, cx: &WindowContext) -> bool {
143 self.id.is_focused(cx)
144 }
145
146 /// Obtains whether the element associated with this handle contains the focused
147 /// element or is itself focused.
148 pub fn contains_focused(&self, cx: &WindowContext) -> bool {
149 self.id.contains_focused(cx)
150 }
151
152 /// Obtains whether the element associated with this handle is contained within the
153 /// focused element or is itself focused.
154 pub fn within_focused(&self, cx: &WindowContext) -> bool {
155 self.id.within_focused(cx)
156 }
157
158 /// Obtains whether this handle contains the given handle in the most recently rendered frame.
159 pub(crate) fn contains(&self, other: &Self, cx: &WindowContext) -> bool {
160 self.id.contains(other.id, cx)
161 }
162}
163
164impl Clone for FocusHandle {
165 fn clone(&self) -> Self {
166 Self::for_id(self.id, &self.handles).unwrap()
167 }
168}
169
170impl PartialEq for FocusHandle {
171 fn eq(&self, other: &Self) -> bool {
172 self.id == other.id
173 }
174}
175
176impl Eq for FocusHandle {}
177
178impl Drop for FocusHandle {
179 fn drop(&mut self) {
180 self.handles
181 .read()
182 .get(self.id)
183 .unwrap()
184 .fetch_sub(1, SeqCst);
185 }
186}
187
188// Holds the state for a specific window.
189pub struct Window {
190 pub(crate) handle: AnyWindowHandle,
191 pub(crate) removed: bool,
192 pub(crate) platform_window: Box<dyn PlatformWindow>,
193 display_id: DisplayId,
194 sprite_atlas: Arc<dyn PlatformAtlas>,
195 rem_size: Pixels,
196 viewport_size: Size<Pixels>,
197 pub(crate) layout_engine: TaffyLayoutEngine,
198 pub(crate) root_view: Option<AnyView>,
199 pub(crate) element_id_stack: GlobalElementId,
200 pub(crate) previous_frame: Frame,
201 pub(crate) current_frame: Frame,
202 pub(crate) focus_handles: Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>,
203 pub(crate) focus_listeners: SubscriberSet<(), AnyWindowFocusListener>,
204 default_prevented: bool,
205 mouse_position: Point<Pixels>,
206 requested_cursor_style: Option<CursorStyle>,
207 scale_factor: f32,
208 bounds: WindowBounds,
209 bounds_observers: SubscriberSet<(), AnyObserver>,
210 active: bool,
211 activation_observers: SubscriberSet<(), AnyObserver>,
212 pub(crate) dirty: bool,
213 pub(crate) last_blur: Option<Option<FocusId>>,
214 pub(crate) focus: Option<FocusId>,
215}
216
217// #[derive(Default)]
218pub(crate) struct Frame {
219 pub(crate) element_states: HashMap<GlobalElementId, AnyBox>,
220 mouse_listeners: HashMap<TypeId, Vec<(StackingOrder, AnyMouseListener)>>,
221 pub(crate) dispatch_tree: DispatchTree,
222 pub(crate) focus_listeners: Vec<AnyFocusListener>,
223 pub(crate) scene_builder: SceneBuilder,
224 z_index_stack: StackingOrder,
225 content_mask_stack: Vec<ContentMask<Pixels>>,
226 element_offset_stack: Vec<Point<Pixels>>,
227}
228
229impl Frame {
230 pub fn new(dispatch_tree: DispatchTree) -> Self {
231 Frame {
232 element_states: HashMap::default(),
233 mouse_listeners: HashMap::default(),
234 dispatch_tree,
235 focus_listeners: Vec::new(),
236 scene_builder: SceneBuilder::default(),
237 z_index_stack: StackingOrder::default(),
238 content_mask_stack: Vec::new(),
239 element_offset_stack: Vec::new(),
240 }
241 }
242}
243
244impl Window {
245 pub(crate) fn new(
246 handle: AnyWindowHandle,
247 options: WindowOptions,
248 cx: &mut AppContext,
249 ) -> Self {
250 let platform_window = cx.platform.open_window(handle, options);
251 let display_id = platform_window.display().id();
252 let sprite_atlas = platform_window.sprite_atlas();
253 let mouse_position = platform_window.mouse_position();
254 let content_size = platform_window.content_size();
255 let scale_factor = platform_window.scale_factor();
256 let bounds = platform_window.bounds();
257
258 platform_window.on_resize(Box::new({
259 let mut cx = cx.to_async();
260 move |_, _| {
261 handle
262 .update(&mut cx, |_, cx| cx.window_bounds_changed())
263 .log_err();
264 }
265 }));
266 platform_window.on_moved(Box::new({
267 let mut cx = cx.to_async();
268 move || {
269 handle
270 .update(&mut cx, |_, cx| cx.window_bounds_changed())
271 .log_err();
272 }
273 }));
274 platform_window.on_active_status_change(Box::new({
275 let mut cx = cx.to_async();
276 move |active| {
277 handle
278 .update(&mut cx, |_, cx| {
279 cx.window.active = active;
280 cx.window
281 .activation_observers
282 .clone()
283 .retain(&(), |callback| callback(cx));
284 })
285 .log_err();
286 }
287 }));
288
289 platform_window.on_input({
290 let mut cx = cx.to_async();
291 Box::new(move |event| {
292 handle
293 .update(&mut cx, |_, cx| cx.dispatch_event(event))
294 .log_err()
295 .unwrap_or(false)
296 })
297 });
298
299 Window {
300 handle,
301 removed: false,
302 platform_window,
303 display_id,
304 sprite_atlas,
305 rem_size: px(16.),
306 viewport_size: content_size,
307 layout_engine: TaffyLayoutEngine::new(),
308 root_view: None,
309 element_id_stack: GlobalElementId::default(),
310 previous_frame: Frame::new(DispatchTree::new(cx.keymap.clone())),
311 current_frame: Frame::new(DispatchTree::new(cx.keymap.clone())),
312 focus_handles: Arc::new(RwLock::new(SlotMap::with_key())),
313 focus_listeners: SubscriberSet::new(),
314 default_prevented: true,
315 mouse_position,
316 requested_cursor_style: None,
317 scale_factor,
318 bounds,
319 bounds_observers: SubscriberSet::new(),
320 active: false,
321 activation_observers: SubscriberSet::new(),
322 dirty: true,
323 last_blur: None,
324 focus: None,
325 }
326 }
327}
328
329/// Indicates which region of the window is visible. Content falling outside of this mask will not be
330/// rendered. Currently, only rectangular content masks are supported, but we give the mask its own type
331/// to leave room to support more complex shapes in the future.
332#[derive(Clone, Debug, Default, PartialEq, Eq)]
333#[repr(C)]
334pub struct ContentMask<P: Clone + Default + Debug> {
335 pub bounds: Bounds<P>,
336}
337
338impl ContentMask<Pixels> {
339 /// Scale the content mask's pixel units by the given scaling factor.
340 pub fn scale(&self, factor: f32) -> ContentMask<ScaledPixels> {
341 ContentMask {
342 bounds: self.bounds.scale(factor),
343 }
344 }
345
346 /// Intersect the content mask with the given content mask.
347 pub fn intersect(&self, other: &Self) -> Self {
348 let bounds = self.bounds.intersect(&other.bounds);
349 ContentMask { bounds }
350 }
351}
352
353/// Provides access to application state in the context of a single window. Derefs
354/// to an `AppContext`, so you can also pass a `WindowContext` to any method that takes
355/// an `AppContext` and call any `AppContext` methods.
356pub struct WindowContext<'a> {
357 pub(crate) app: &'a mut AppContext,
358 pub(crate) window: &'a mut Window,
359}
360
361impl<'a> WindowContext<'a> {
362 pub(crate) fn new(app: &'a mut AppContext, window: &'a mut Window) -> Self {
363 Self { app, window }
364 }
365
366 /// Obtain a handle to the window that belongs to this context.
367 pub fn window_handle(&self) -> AnyWindowHandle {
368 self.window.handle
369 }
370
371 /// Mark the window as dirty, scheduling it to be redrawn on the next frame.
372 pub fn notify(&mut self) {
373 self.window.dirty = true;
374 }
375
376 /// Close this window.
377 pub fn remove_window(&mut self) {
378 self.window.removed = true;
379 }
380
381 /// Obtain a new `FocusHandle`, which allows you to track and manipulate the keyboard focus
382 /// for elements rendered within this window.
383 pub fn focus_handle(&mut self) -> FocusHandle {
384 FocusHandle::new(&self.window.focus_handles)
385 }
386
387 /// Obtain the currently focused `FocusHandle`. If no elements are focused, returns `None`.
388 pub fn focused(&self) -> Option<FocusHandle> {
389 self.window
390 .focus
391 .and_then(|id| FocusHandle::for_id(id, &self.window.focus_handles))
392 }
393
394 /// Move focus to the element associated with the given `FocusHandle`.
395 pub fn focus(&mut self, handle: &FocusHandle) {
396 if self.window.focus == Some(handle.id) {
397 return;
398 }
399
400 let focus_id = handle.id;
401
402 if self.window.last_blur.is_none() {
403 self.window.last_blur = Some(self.window.focus);
404 }
405
406 self.window.focus = Some(focus_id);
407 self.window
408 .current_frame
409 .dispatch_tree
410 .clear_keystroke_matchers();
411 self.app.push_effect(Effect::FocusChanged {
412 window_handle: self.window.handle,
413 focused: Some(focus_id),
414 });
415 self.notify();
416 }
417
418 /// Remove focus from all elements within this context's window.
419 pub fn blur(&mut self) {
420 if self.window.last_blur.is_none() {
421 self.window.last_blur = Some(self.window.focus);
422 }
423
424 self.window.focus = None;
425 self.app.push_effect(Effect::FocusChanged {
426 window_handle: self.window.handle,
427 focused: None,
428 });
429 self.notify();
430 }
431
432 pub fn dispatch_action(&mut self, action: Box<dyn Action>) {
433 if let Some(focus_handle) = self.focused() {
434 self.defer(move |cx| {
435 if let Some(node_id) = cx
436 .window
437 .current_frame
438 .dispatch_tree
439 .focusable_node_id(focus_handle.id)
440 {
441 cx.propagate_event = true;
442 cx.dispatch_action_on_node(node_id, action);
443 }
444 })
445 }
446 }
447
448 /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
449 /// that are currently on the stack to be returned to the app.
450 pub fn defer(&mut self, f: impl FnOnce(&mut WindowContext) + 'static) {
451 let handle = self.window.handle;
452 self.app.defer(move |cx| {
453 handle.update(cx, |_, cx| f(cx)).ok();
454 });
455 }
456
457 pub fn subscribe<Emitter, E, Evt>(
458 &mut self,
459 entity: &E,
460 mut on_event: impl FnMut(E, &Evt, &mut WindowContext<'_>) + 'static,
461 ) -> Subscription
462 where
463 Emitter: EventEmitter<Evt>,
464 E: Entity<Emitter>,
465 Evt: 'static,
466 {
467 let entity_id = entity.entity_id();
468 let entity = entity.downgrade();
469 let window_handle = self.window.handle;
470 self.app.event_listeners.insert(
471 entity_id,
472 (
473 TypeId::of::<Evt>(),
474 Box::new(move |event, cx| {
475 window_handle
476 .update(cx, |_, cx| {
477 if let Some(handle) = E::upgrade_from(&entity) {
478 let event = event.downcast_ref().expect("invalid event type");
479 on_event(handle, event, cx);
480 true
481 } else {
482 false
483 }
484 })
485 .unwrap_or(false)
486 }),
487 ),
488 )
489 }
490
491 /// Create an `AsyncWindowContext`, which has a static lifetime and can be held across
492 /// await points in async code.
493 pub fn to_async(&self) -> AsyncWindowContext {
494 AsyncWindowContext::new(self.app.to_async(), self.window.handle)
495 }
496
497 /// Schedule the given closure to be run directly after the current frame is rendered.
498 pub fn on_next_frame(&mut self, callback: impl FnOnce(&mut WindowContext) + 'static) {
499 let handle = self.window.handle;
500 let display_id = self.window.display_id;
501
502 if !self.frame_consumers.contains_key(&display_id) {
503 let (tx, mut rx) = mpsc::unbounded::<()>();
504 self.platform.set_display_link_output_callback(
505 display_id,
506 Box::new(move |_current_time, _output_time| _ = tx.unbounded_send(())),
507 );
508
509 let consumer_task = self.app.spawn(|cx| async move {
510 while rx.next().await.is_some() {
511 cx.update(|cx| {
512 for callback in cx
513 .next_frame_callbacks
514 .get_mut(&display_id)
515 .unwrap()
516 .drain(..)
517 .collect::<SmallVec<[_; 32]>>()
518 {
519 callback(cx);
520 }
521 })
522 .ok();
523
524 // Flush effects, then stop the display link if no new next_frame_callbacks have been added.
525
526 cx.update(|cx| {
527 if cx.next_frame_callbacks.is_empty() {
528 cx.platform.stop_display_link(display_id);
529 }
530 })
531 .ok();
532 }
533 });
534 self.frame_consumers.insert(display_id, consumer_task);
535 }
536
537 if self.next_frame_callbacks.is_empty() {
538 self.platform.start_display_link(display_id);
539 }
540
541 self.next_frame_callbacks
542 .entry(display_id)
543 .or_default()
544 .push(Box::new(move |cx: &mut AppContext| {
545 cx.update_window(handle, |_root_view, cx| callback(cx)).ok();
546 }));
547 }
548
549 /// Spawn the future returned by the given closure on the application thread pool.
550 /// The closure is provided a handle to the current window and an `AsyncWindowContext` for
551 /// use within your future.
552 pub fn spawn<Fut, R>(&mut self, f: impl FnOnce(AsyncWindowContext) -> Fut) -> Task<R>
553 where
554 R: 'static,
555 Fut: Future<Output = R> + 'static,
556 {
557 self.app
558 .spawn(|app| f(AsyncWindowContext::new(app, self.window.handle)))
559 }
560
561 /// Update the global of the given type. The given closure is given simultaneous mutable
562 /// access both to the global and the context.
563 pub fn update_global<G, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R
564 where
565 G: 'static,
566 {
567 let mut global = self.app.lease_global::<G>();
568 let result = f(&mut global, self);
569 self.app.end_global_lease(global);
570 result
571 }
572
573 /// Add a node to the layout tree for the current frame. Takes the `Style` of the element for which
574 /// layout is being requested, along with the layout ids of any children. This method is called during
575 /// calls to the `Element::layout` trait method and enables any element to participate in layout.
576 pub fn request_layout(
577 &mut self,
578 style: &Style,
579 children: impl IntoIterator<Item = LayoutId>,
580 ) -> LayoutId {
581 self.app.layout_id_buffer.clear();
582 self.app.layout_id_buffer.extend(children.into_iter());
583 let rem_size = self.rem_size();
584
585 self.window
586 .layout_engine
587 .request_layout(style, rem_size, &self.app.layout_id_buffer)
588 }
589
590 /// Add a node to the layout tree for the current frame. Instead of taking a `Style` and children,
591 /// this variant takes a function that is invoked during layout so you can use arbitrary logic to
592 /// determine the element's size. One place this is used internally is when measuring text.
593 ///
594 /// The given closure is invoked at layout time with the known dimensions and available space and
595 /// returns a `Size`.
596 pub fn request_measured_layout<
597 F: Fn(Size<Option<Pixels>>, Size<AvailableSpace>) -> Size<Pixels> + Send + Sync + 'static,
598 >(
599 &mut self,
600 style: Style,
601 rem_size: Pixels,
602 measure: F,
603 ) -> LayoutId {
604 self.window
605 .layout_engine
606 .request_measured_layout(style, rem_size, measure)
607 }
608
609 pub fn compute_layout(&mut self, layout_id: LayoutId, available_space: Size<AvailableSpace>) {
610 self.window
611 .layout_engine
612 .compute_layout(layout_id, available_space)
613 }
614
615 /// Obtain the bounds computed for the given LayoutId relative to the window. This method should not
616 /// be invoked until the paint phase begins, and will usually be invoked by GPUI itself automatically
617 /// in order to pass your element its `Bounds` automatically.
618 pub fn layout_bounds(&mut self, layout_id: LayoutId) -> Bounds<Pixels> {
619 let mut bounds = self
620 .window
621 .layout_engine
622 .layout_bounds(layout_id)
623 .map(Into::into);
624 bounds.origin += self.element_offset();
625 bounds
626 }
627
628 fn window_bounds_changed(&mut self) {
629 self.window.scale_factor = self.window.platform_window.scale_factor();
630 self.window.viewport_size = self.window.platform_window.content_size();
631 self.window.bounds = self.window.platform_window.bounds();
632 self.window.display_id = self.window.platform_window.display().id();
633 self.window.dirty = true;
634
635 self.window
636 .bounds_observers
637 .clone()
638 .retain(&(), |callback| callback(self));
639 }
640
641 pub fn window_bounds(&self) -> WindowBounds {
642 self.window.bounds
643 }
644
645 pub fn viewport_size(&self) -> Size<Pixels> {
646 self.window.viewport_size
647 }
648
649 pub fn is_window_active(&self) -> bool {
650 self.window.active
651 }
652
653 pub fn zoom_window(&self) {
654 self.window.platform_window.zoom();
655 }
656
657 pub fn display(&self) -> Option<Rc<dyn PlatformDisplay>> {
658 self.platform
659 .displays()
660 .into_iter()
661 .find(|display| display.id() == self.window.display_id)
662 }
663
664 pub fn show_character_palette(&self) {
665 self.window.platform_window.show_character_palette();
666 }
667
668 /// The scale factor of the display associated with the window. For example, it could
669 /// return 2.0 for a "retina" display, indicating that each logical pixel should actually
670 /// be rendered as two pixels on screen.
671 pub fn scale_factor(&self) -> f32 {
672 self.window.scale_factor
673 }
674
675 /// The size of an em for the base font of the application. Adjusting this value allows the
676 /// UI to scale, just like zooming a web page.
677 pub fn rem_size(&self) -> Pixels {
678 self.window.rem_size
679 }
680
681 /// Sets the size of an em for the base font of the application. Adjusting this value allows the
682 /// UI to scale, just like zooming a web page.
683 pub fn set_rem_size(&mut self, rem_size: impl Into<Pixels>) {
684 self.window.rem_size = rem_size.into();
685 }
686
687 /// The line height associated with the current text style.
688 pub fn line_height(&self) -> Pixels {
689 let rem_size = self.rem_size();
690 let text_style = self.text_style();
691 text_style
692 .line_height
693 .to_pixels(text_style.font_size.into(), rem_size)
694 }
695
696 /// Call to prevent the default action of an event. Currently only used to prevent
697 /// parent elements from becoming focused on mouse down.
698 pub fn prevent_default(&mut self) {
699 self.window.default_prevented = true;
700 }
701
702 /// Obtain whether default has been prevented for the event currently being dispatched.
703 pub fn default_prevented(&self) -> bool {
704 self.window.default_prevented
705 }
706
707 /// Register a mouse event listener on the window for the current frame. The type of event
708 /// is determined by the first parameter of the given listener. When the next frame is rendered
709 /// the listener will be cleared.
710 ///
711 /// This is a fairly low-level method, so prefer using event handlers on elements unless you have
712 /// a specific need to register a global listener.
713 pub fn on_mouse_event<Event: 'static>(
714 &mut self,
715 handler: impl Fn(&Event, DispatchPhase, &mut WindowContext) + 'static,
716 ) {
717 let order = self.window.current_frame.z_index_stack.clone();
718 self.window
719 .current_frame
720 .mouse_listeners
721 .entry(TypeId::of::<Event>())
722 .or_default()
723 .push((
724 order,
725 Box::new(move |event: &dyn Any, phase, cx| {
726 handler(event.downcast_ref().unwrap(), phase, cx)
727 }),
728 ))
729 }
730
731 /// Register a key event listener on the window for the current frame. The type of event
732 /// is determined by the first parameter of the given listener. When the next frame is rendered
733 /// the listener will be cleared.
734 ///
735 /// This is a fairly low-level method, so prefer using event handlers on elements unless you have
736 /// a specific need to register a global listener.
737 pub fn on_key_event<Event: 'static>(
738 &mut self,
739 handler: impl Fn(&Event, DispatchPhase, &mut WindowContext) + 'static,
740 ) {
741 self.window
742 .current_frame
743 .dispatch_tree
744 .on_key_event(Rc::new(move |event, phase, cx| {
745 if let Some(event) = event.downcast_ref::<Event>() {
746 handler(event, phase, cx)
747 }
748 }));
749 }
750
751 /// Register an action listener on the window for the current frame. The type of action
752 /// is determined by the first parameter of the given listener. When the next frame is rendered
753 /// the listener will be cleared.
754 ///
755 /// This is a fairly low-level method, so prefer using action handlers on elements unless you have
756 /// a specific need to register a global listener.
757 pub fn on_action(
758 &mut self,
759 action_type: TypeId,
760 handler: impl Fn(&dyn Any, DispatchPhase, &mut WindowContext) + 'static,
761 ) {
762 self.window.current_frame.dispatch_tree.on_action(
763 action_type,
764 Rc::new(move |action, phase, cx| handler(action, phase, cx)),
765 );
766 }
767
768 /// The position of the mouse relative to the window.
769 pub fn mouse_position(&self) -> Point<Pixels> {
770 self.window.mouse_position
771 }
772
773 pub fn set_cursor_style(&mut self, style: CursorStyle) {
774 self.window.requested_cursor_style = Some(style)
775 }
776
777 /// Called during painting to invoke the given closure in a new stacking context. The given
778 /// z-index is interpreted relative to the previous call to `stack`.
779 pub fn with_z_index<R>(&mut self, z_index: u32, f: impl FnOnce(&mut Self) -> R) -> R {
780 self.window.current_frame.z_index_stack.push(z_index);
781 let result = f(self);
782 self.window.current_frame.z_index_stack.pop();
783 result
784 }
785
786 /// Paint one or more drop shadows into the scene for the current frame at the current z-index.
787 pub fn paint_shadows(
788 &mut self,
789 bounds: Bounds<Pixels>,
790 corner_radii: Corners<Pixels>,
791 shadows: &[BoxShadow],
792 ) {
793 let scale_factor = self.scale_factor();
794 let content_mask = self.content_mask();
795 let window = &mut *self.window;
796 for shadow in shadows {
797 let mut shadow_bounds = bounds;
798 shadow_bounds.origin += shadow.offset;
799 shadow_bounds.dilate(shadow.spread_radius);
800 window.current_frame.scene_builder.insert(
801 &window.current_frame.z_index_stack,
802 Shadow {
803 order: 0,
804 bounds: shadow_bounds.scale(scale_factor),
805 content_mask: content_mask.scale(scale_factor),
806 corner_radii: corner_radii.scale(scale_factor),
807 color: shadow.color,
808 blur_radius: shadow.blur_radius.scale(scale_factor),
809 },
810 );
811 }
812 }
813
814 /// Paint one or more quads into the scene for the current frame at the current stacking context.
815 /// Quads are colored rectangular regions with an optional background, border, and corner radius.
816 pub fn paint_quad(
817 &mut self,
818 bounds: Bounds<Pixels>,
819 corner_radii: Corners<Pixels>,
820 background: impl Into<Hsla>,
821 border_widths: Edges<Pixels>,
822 border_color: impl Into<Hsla>,
823 ) {
824 let scale_factor = self.scale_factor();
825 let content_mask = self.content_mask();
826
827 let window = &mut *self.window;
828 window.current_frame.scene_builder.insert(
829 &window.current_frame.z_index_stack,
830 Quad {
831 order: 0,
832 bounds: bounds.scale(scale_factor),
833 content_mask: content_mask.scale(scale_factor),
834 background: background.into(),
835 border_color: border_color.into(),
836 corner_radii: corner_radii.scale(scale_factor),
837 border_widths: border_widths.scale(scale_factor),
838 },
839 );
840 }
841
842 /// Paint the given `Path` into the scene for the current frame at the current z-index.
843 pub fn paint_path(&mut self, mut path: Path<Pixels>, color: impl Into<Hsla>) {
844 let scale_factor = self.scale_factor();
845 let content_mask = self.content_mask();
846 path.content_mask = content_mask;
847 path.color = color.into();
848 let window = &mut *self.window;
849 window.current_frame.scene_builder.insert(
850 &window.current_frame.z_index_stack,
851 path.scale(scale_factor),
852 );
853 }
854
855 /// Paint an underline into the scene for the current frame at the current z-index.
856 pub fn paint_underline(
857 &mut self,
858 origin: Point<Pixels>,
859 width: Pixels,
860 style: &UnderlineStyle,
861 ) -> Result<()> {
862 let scale_factor = self.scale_factor();
863 let height = if style.wavy {
864 style.thickness * 3.
865 } else {
866 style.thickness
867 };
868 let bounds = Bounds {
869 origin,
870 size: size(width, height),
871 };
872 let content_mask = self.content_mask();
873 let window = &mut *self.window;
874 window.current_frame.scene_builder.insert(
875 &window.current_frame.z_index_stack,
876 Underline {
877 order: 0,
878 bounds: bounds.scale(scale_factor),
879 content_mask: content_mask.scale(scale_factor),
880 thickness: style.thickness.scale(scale_factor),
881 color: style.color.unwrap_or_default(),
882 wavy: style.wavy,
883 },
884 );
885 Ok(())
886 }
887
888 /// Paint a monochrome (non-emoji) glyph into the scene for the current frame at the current z-index.
889 /// The y component of the origin is the baseline of the glyph.
890 pub fn paint_glyph(
891 &mut self,
892 origin: Point<Pixels>,
893 font_id: FontId,
894 glyph_id: GlyphId,
895 font_size: Pixels,
896 color: Hsla,
897 ) -> Result<()> {
898 let scale_factor = self.scale_factor();
899 let glyph_origin = origin.scale(scale_factor);
900 let subpixel_variant = Point {
901 x: (glyph_origin.x.0.fract() * SUBPIXEL_VARIANTS as f32).floor() as u8,
902 y: (glyph_origin.y.0.fract() * SUBPIXEL_VARIANTS as f32).floor() as u8,
903 };
904 let params = RenderGlyphParams {
905 font_id,
906 glyph_id,
907 font_size,
908 subpixel_variant,
909 scale_factor,
910 is_emoji: false,
911 };
912
913 let raster_bounds = self.text_system().raster_bounds(¶ms)?;
914 if !raster_bounds.is_zero() {
915 let tile =
916 self.window
917 .sprite_atlas
918 .get_or_insert_with(¶ms.clone().into(), &mut || {
919 let (size, bytes) = self.text_system().rasterize_glyph(¶ms)?;
920 Ok((size, Cow::Owned(bytes)))
921 })?;
922 let bounds = Bounds {
923 origin: glyph_origin.map(|px| px.floor()) + raster_bounds.origin.map(Into::into),
924 size: tile.bounds.size.map(Into::into),
925 };
926 let content_mask = self.content_mask().scale(scale_factor);
927 let window = &mut *self.window;
928 window.current_frame.scene_builder.insert(
929 &window.current_frame.z_index_stack,
930 MonochromeSprite {
931 order: 0,
932 bounds,
933 content_mask,
934 color,
935 tile,
936 },
937 );
938 }
939 Ok(())
940 }
941
942 /// Paint an emoji glyph into the scene for the current frame at the current z-index.
943 /// The y component of the origin is the baseline of the glyph.
944 pub fn paint_emoji(
945 &mut self,
946 origin: Point<Pixels>,
947 font_id: FontId,
948 glyph_id: GlyphId,
949 font_size: Pixels,
950 ) -> Result<()> {
951 let scale_factor = self.scale_factor();
952 let glyph_origin = origin.scale(scale_factor);
953 let params = RenderGlyphParams {
954 font_id,
955 glyph_id,
956 font_size,
957 // We don't render emojis with subpixel variants.
958 subpixel_variant: Default::default(),
959 scale_factor,
960 is_emoji: true,
961 };
962
963 let raster_bounds = self.text_system().raster_bounds(¶ms)?;
964 if !raster_bounds.is_zero() {
965 let tile =
966 self.window
967 .sprite_atlas
968 .get_or_insert_with(¶ms.clone().into(), &mut || {
969 let (size, bytes) = self.text_system().rasterize_glyph(¶ms)?;
970 Ok((size, Cow::Owned(bytes)))
971 })?;
972 let bounds = Bounds {
973 origin: glyph_origin.map(|px| px.floor()) + raster_bounds.origin.map(Into::into),
974 size: tile.bounds.size.map(Into::into),
975 };
976 let content_mask = self.content_mask().scale(scale_factor);
977 let window = &mut *self.window;
978
979 window.current_frame.scene_builder.insert(
980 &window.current_frame.z_index_stack,
981 PolychromeSprite {
982 order: 0,
983 bounds,
984 corner_radii: Default::default(),
985 content_mask,
986 tile,
987 grayscale: false,
988 },
989 );
990 }
991 Ok(())
992 }
993
994 /// Paint a monochrome SVG into the scene for the current frame at the current stacking context.
995 pub fn paint_svg(
996 &mut self,
997 bounds: Bounds<Pixels>,
998 path: SharedString,
999 color: Hsla,
1000 ) -> Result<()> {
1001 let scale_factor = self.scale_factor();
1002 let bounds = bounds.scale(scale_factor);
1003 // Render the SVG at twice the size to get a higher quality result.
1004 let params = RenderSvgParams {
1005 path,
1006 size: bounds
1007 .size
1008 .map(|pixels| DevicePixels::from((pixels.0 * 2.).ceil() as i32)),
1009 };
1010
1011 let tile =
1012 self.window
1013 .sprite_atlas
1014 .get_or_insert_with(¶ms.clone().into(), &mut || {
1015 let bytes = self.svg_renderer.render(¶ms)?;
1016 Ok((params.size, Cow::Owned(bytes)))
1017 })?;
1018 let content_mask = self.content_mask().scale(scale_factor);
1019
1020 let window = &mut *self.window;
1021 window.current_frame.scene_builder.insert(
1022 &window.current_frame.z_index_stack,
1023 MonochromeSprite {
1024 order: 0,
1025 bounds,
1026 content_mask,
1027 color,
1028 tile,
1029 },
1030 );
1031
1032 Ok(())
1033 }
1034
1035 /// Paint an image into the scene for the current frame at the current z-index.
1036 pub fn paint_image(
1037 &mut self,
1038 bounds: Bounds<Pixels>,
1039 corner_radii: Corners<Pixels>,
1040 data: Arc<ImageData>,
1041 grayscale: bool,
1042 ) -> Result<()> {
1043 let scale_factor = self.scale_factor();
1044 let bounds = bounds.scale(scale_factor);
1045 let params = RenderImageParams { image_id: data.id };
1046
1047 let tile = self
1048 .window
1049 .sprite_atlas
1050 .get_or_insert_with(¶ms.clone().into(), &mut || {
1051 Ok((data.size(), Cow::Borrowed(data.as_bytes())))
1052 })?;
1053 let content_mask = self.content_mask().scale(scale_factor);
1054 let corner_radii = corner_radii.scale(scale_factor);
1055
1056 let window = &mut *self.window;
1057 window.current_frame.scene_builder.insert(
1058 &window.current_frame.z_index_stack,
1059 PolychromeSprite {
1060 order: 0,
1061 bounds,
1062 content_mask,
1063 corner_radii,
1064 tile,
1065 grayscale,
1066 },
1067 );
1068 Ok(())
1069 }
1070
1071 /// Draw pixels to the display for this window based on the contents of its scene.
1072 pub(crate) fn draw(&mut self) {
1073 let root_view = self.window.root_view.take().unwrap();
1074
1075 self.start_frame();
1076
1077 self.with_z_index(0, |cx| {
1078 let available_space = cx.window.viewport_size.map(Into::into);
1079 root_view.draw(available_space, cx);
1080 });
1081
1082 if let Some(active_drag) = self.app.active_drag.take() {
1083 self.with_z_index(1, |cx| {
1084 let offset = cx.mouse_position() - active_drag.cursor_offset;
1085 cx.with_element_offset(offset, |cx| {
1086 let available_space =
1087 size(AvailableSpace::MinContent, AvailableSpace::MinContent);
1088 active_drag.view.draw(available_space, cx);
1089 cx.active_drag = Some(active_drag);
1090 });
1091 });
1092 } else if let Some(active_tooltip) = self.app.active_tooltip.take() {
1093 self.with_z_index(1, |cx| {
1094 cx.with_element_offset(active_tooltip.cursor_offset, |cx| {
1095 let available_space =
1096 size(AvailableSpace::MinContent, AvailableSpace::MinContent);
1097 active_tooltip.view.draw(available_space, cx);
1098 });
1099 });
1100 }
1101
1102 self.window
1103 .current_frame
1104 .dispatch_tree
1105 .preserve_keystroke_matchers(
1106 &mut self.window.previous_frame.dispatch_tree,
1107 self.window.focus,
1108 );
1109
1110 self.window.root_view = Some(root_view);
1111 let scene = self.window.current_frame.scene_builder.build();
1112
1113 self.window.platform_window.draw(scene);
1114 let cursor_style = self
1115 .window
1116 .requested_cursor_style
1117 .take()
1118 .unwrap_or(CursorStyle::Arrow);
1119 self.platform.set_cursor_style(cursor_style);
1120
1121 self.window.dirty = false;
1122 }
1123
1124 /// Rotate the current frame and the previous frame, then clear the current frame.
1125 /// We repopulate all state in the current frame during each paint.
1126 fn start_frame(&mut self) {
1127 self.text_system().start_frame();
1128
1129 let window = &mut *self.window;
1130 window.layout_engine.clear();
1131
1132 mem::swap(&mut window.previous_frame, &mut window.current_frame);
1133 let frame = &mut window.current_frame;
1134 frame.element_states.clear();
1135 frame.mouse_listeners.values_mut().for_each(Vec::clear);
1136 frame.focus_listeners.clear();
1137 frame.dispatch_tree.clear();
1138 }
1139
1140 /// Dispatch a mouse or keyboard event on the window.
1141 pub fn dispatch_event(&mut self, event: InputEvent) -> bool {
1142 // Handlers may set this to false by calling `stop_propagation`
1143 self.app.propagate_event = true;
1144 self.window.default_prevented = false;
1145
1146 let event = match event {
1147 // Track the mouse position with our own state, since accessing the platform
1148 // API for the mouse position can only occur on the main thread.
1149 InputEvent::MouseMove(mouse_move) => {
1150 self.window.mouse_position = mouse_move.position;
1151 InputEvent::MouseMove(mouse_move)
1152 }
1153 // Translate dragging and dropping of external files from the operating system
1154 // to internal drag and drop events.
1155 InputEvent::FileDrop(file_drop) => match file_drop {
1156 FileDropEvent::Entered { position, files } => {
1157 self.window.mouse_position = position;
1158 if self.active_drag.is_none() {
1159 self.active_drag = Some(AnyDrag {
1160 view: self.build_view(|_| files).into(),
1161 cursor_offset: position,
1162 });
1163 }
1164 InputEvent::MouseDown(MouseDownEvent {
1165 position,
1166 button: MouseButton::Left,
1167 click_count: 1,
1168 modifiers: Modifiers::default(),
1169 })
1170 }
1171 FileDropEvent::Pending { position } => {
1172 self.window.mouse_position = position;
1173 InputEvent::MouseMove(MouseMoveEvent {
1174 position,
1175 pressed_button: Some(MouseButton::Left),
1176 modifiers: Modifiers::default(),
1177 })
1178 }
1179 FileDropEvent::Submit { position } => {
1180 self.window.mouse_position = position;
1181 InputEvent::MouseUp(MouseUpEvent {
1182 button: MouseButton::Left,
1183 position,
1184 modifiers: Modifiers::default(),
1185 click_count: 1,
1186 })
1187 }
1188 FileDropEvent::Exited => InputEvent::MouseUp(MouseUpEvent {
1189 button: MouseButton::Left,
1190 position: Point::default(),
1191 modifiers: Modifiers::default(),
1192 click_count: 1,
1193 }),
1194 },
1195 _ => event,
1196 };
1197
1198 if let Some(any_mouse_event) = event.mouse_event() {
1199 self.dispatch_mouse_event(any_mouse_event);
1200 } else if let Some(any_key_event) = event.keyboard_event() {
1201 self.dispatch_key_event(any_key_event);
1202 }
1203
1204 !self.app.propagate_event
1205 }
1206
1207 fn dispatch_mouse_event(&mut self, event: &dyn Any) {
1208 if let Some(mut handlers) = self
1209 .window
1210 .current_frame
1211 .mouse_listeners
1212 .remove(&event.type_id())
1213 {
1214 // Because handlers may add other handlers, we sort every time.
1215 handlers.sort_by(|(a, _), (b, _)| a.cmp(b));
1216
1217 // Capture phase, events bubble from back to front. Handlers for this phase are used for
1218 // special purposes, such as detecting events outside of a given Bounds.
1219 for (_, handler) in &mut handlers {
1220 handler(event, DispatchPhase::Capture, self);
1221 if !self.app.propagate_event {
1222 break;
1223 }
1224 }
1225
1226 // Bubble phase, where most normal handlers do their work.
1227 if self.app.propagate_event {
1228 for (_, handler) in handlers.iter_mut().rev() {
1229 handler(event, DispatchPhase::Bubble, self);
1230 if !self.app.propagate_event {
1231 break;
1232 }
1233 }
1234 }
1235
1236 if self.app.propagate_event && event.downcast_ref::<MouseUpEvent>().is_some() {
1237 self.active_drag = None;
1238 }
1239
1240 // Just in case any handlers added new handlers, which is weird, but possible.
1241 handlers.extend(
1242 self.window
1243 .current_frame
1244 .mouse_listeners
1245 .get_mut(&event.type_id())
1246 .into_iter()
1247 .flat_map(|handlers| handlers.drain(..)),
1248 );
1249 self.window
1250 .current_frame
1251 .mouse_listeners
1252 .insert(event.type_id(), handlers);
1253 }
1254 }
1255
1256 fn dispatch_key_event(&mut self, event: &dyn Any) {
1257 if let Some(node_id) = self.window.focus.and_then(|focus_id| {
1258 self.window
1259 .current_frame
1260 .dispatch_tree
1261 .focusable_node_id(focus_id)
1262 }) {
1263 let dispatch_path = self
1264 .window
1265 .current_frame
1266 .dispatch_tree
1267 .dispatch_path(node_id);
1268
1269 // Capture phase
1270 let mut context_stack: SmallVec<[KeyContext; 16]> = SmallVec::new();
1271 self.propagate_event = true;
1272
1273 for node_id in &dispatch_path {
1274 let node = self.window.current_frame.dispatch_tree.node(*node_id);
1275
1276 if !node.context.is_empty() {
1277 context_stack.push(node.context.clone());
1278 }
1279
1280 for key_listener in node.key_listeners.clone() {
1281 key_listener(event, DispatchPhase::Capture, self);
1282 if !self.propagate_event {
1283 return;
1284 }
1285 }
1286 }
1287
1288 // Bubble phase
1289 for node_id in dispatch_path.iter().rev() {
1290 // Handle low level key events
1291 let node = self.window.current_frame.dispatch_tree.node(*node_id);
1292 for key_listener in node.key_listeners.clone() {
1293 key_listener(event, DispatchPhase::Bubble, self);
1294 if !self.propagate_event {
1295 return;
1296 }
1297 }
1298
1299 // Match keystrokes
1300 let node = self.window.current_frame.dispatch_tree.node(*node_id);
1301 if !node.context.is_empty() {
1302 if let Some(key_down_event) = event.downcast_ref::<KeyDownEvent>() {
1303 if let Some(action) = self
1304 .window
1305 .current_frame
1306 .dispatch_tree
1307 .dispatch_key(&key_down_event.keystroke, &context_stack)
1308 {
1309 self.dispatch_action_on_node(*node_id, action);
1310 if !self.propagate_event {
1311 return;
1312 }
1313 }
1314 }
1315
1316 context_stack.pop();
1317 }
1318 }
1319 }
1320 }
1321
1322 fn dispatch_action_on_node(&mut self, node_id: DispatchNodeId, action: Box<dyn Action>) {
1323 let dispatch_path = self
1324 .window
1325 .current_frame
1326 .dispatch_tree
1327 .dispatch_path(node_id);
1328
1329 // Capture phase
1330 for node_id in &dispatch_path {
1331 let node = self.window.current_frame.dispatch_tree.node(*node_id);
1332 for DispatchActionListener {
1333 action_type,
1334 listener,
1335 } in node.action_listeners.clone()
1336 {
1337 let any_action = action.as_any();
1338 if action_type == any_action.type_id() {
1339 listener(any_action, DispatchPhase::Capture, self);
1340 if !self.propagate_event {
1341 return;
1342 }
1343 }
1344 }
1345 }
1346
1347 // Bubble phase
1348 for node_id in dispatch_path.iter().rev() {
1349 let node = self.window.current_frame.dispatch_tree.node(*node_id);
1350 for DispatchActionListener {
1351 action_type,
1352 listener,
1353 } in node.action_listeners.clone()
1354 {
1355 let any_action = action.as_any();
1356 if action_type == any_action.type_id() {
1357 self.propagate_event = false; // Actions stop propagation by default during the bubble phase
1358 listener(any_action, DispatchPhase::Bubble, self);
1359 if !self.propagate_event {
1360 return;
1361 }
1362 }
1363 }
1364 }
1365 }
1366
1367 /// Register the given handler to be invoked whenever the global of the given type
1368 /// is updated.
1369 pub fn observe_global<G: 'static>(
1370 &mut self,
1371 f: impl Fn(&mut WindowContext<'_>) + 'static,
1372 ) -> Subscription {
1373 let window_handle = self.window.handle;
1374 self.global_observers.insert(
1375 TypeId::of::<G>(),
1376 Box::new(move |cx| window_handle.update(cx, |_, cx| f(cx)).is_ok()),
1377 )
1378 }
1379
1380 pub fn activate_window(&self) {
1381 self.window.platform_window.activate();
1382 }
1383
1384 pub fn minimize_window(&self) {
1385 self.window.platform_window.minimize();
1386 }
1387
1388 pub fn toggle_full_screen(&self) {
1389 self.window.platform_window.toggle_full_screen();
1390 }
1391
1392 pub fn prompt(
1393 &self,
1394 level: PromptLevel,
1395 msg: &str,
1396 answers: &[&str],
1397 ) -> oneshot::Receiver<usize> {
1398 self.window.platform_window.prompt(level, msg, answers)
1399 }
1400
1401 pub fn available_actions(&self) -> Vec<Box<dyn Action>> {
1402 if let Some(focus_id) = self.window.focus {
1403 self.window
1404 .current_frame
1405 .dispatch_tree
1406 .available_actions(focus_id)
1407 } else {
1408 Vec::new()
1409 }
1410 }
1411
1412 pub fn bindings_for_action(&self, action: &dyn Action) -> Vec<KeyBinding> {
1413 self.window
1414 .current_frame
1415 .dispatch_tree
1416 .bindings_for_action(action)
1417 }
1418}
1419
1420impl Context for WindowContext<'_> {
1421 type Result<T> = T;
1422
1423 fn build_model<T>(
1424 &mut self,
1425 build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
1426 ) -> Model<T>
1427 where
1428 T: 'static,
1429 {
1430 let slot = self.app.entities.reserve();
1431 let model = build_model(&mut ModelContext::new(&mut *self.app, slot.downgrade()));
1432 self.entities.insert(slot, model)
1433 }
1434
1435 fn update_model<T: 'static, R>(
1436 &mut self,
1437 model: &Model<T>,
1438 update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
1439 ) -> R {
1440 let mut entity = self.entities.lease(model);
1441 let result = update(
1442 &mut *entity,
1443 &mut ModelContext::new(&mut *self.app, model.downgrade()),
1444 );
1445 self.entities.end_lease(entity);
1446 result
1447 }
1448
1449 fn update_window<T, F>(&mut self, window: AnyWindowHandle, update: F) -> Result<T>
1450 where
1451 F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
1452 {
1453 if window == self.window.handle {
1454 let root_view = self.window.root_view.clone().unwrap();
1455 Ok(update(root_view, self))
1456 } else {
1457 window.update(self.app, update)
1458 }
1459 }
1460
1461 fn read_model<T, R>(
1462 &self,
1463 handle: &Model<T>,
1464 read: impl FnOnce(&T, &AppContext) -> R,
1465 ) -> Self::Result<R>
1466 where
1467 T: 'static,
1468 {
1469 let entity = self.entities.read(handle);
1470 read(&*entity, &*self.app)
1471 }
1472
1473 fn read_window<T, R>(
1474 &self,
1475 window: &WindowHandle<T>,
1476 read: impl FnOnce(View<T>, &AppContext) -> R,
1477 ) -> Result<R>
1478 where
1479 T: 'static,
1480 {
1481 if window.any_handle == self.window.handle {
1482 let root_view = self
1483 .window
1484 .root_view
1485 .clone()
1486 .unwrap()
1487 .downcast::<T>()
1488 .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
1489 Ok(read(root_view, self))
1490 } else {
1491 self.app.read_window(window, read)
1492 }
1493 }
1494}
1495
1496impl VisualContext for WindowContext<'_> {
1497 fn build_view<V>(
1498 &mut self,
1499 build_view_state: impl FnOnce(&mut ViewContext<'_, V>) -> V,
1500 ) -> Self::Result<View<V>>
1501 where
1502 V: 'static + Render,
1503 {
1504 let slot = self.app.entities.reserve();
1505 let view = View {
1506 model: slot.clone(),
1507 };
1508 let mut cx = ViewContext::new(&mut *self.app, &mut *self.window, &view);
1509 let entity = build_view_state(&mut cx);
1510 cx.entities.insert(slot, entity);
1511
1512 cx.new_view_observers
1513 .clone()
1514 .retain(&TypeId::of::<V>(), |observer| {
1515 let any_view = AnyView::from(view.clone());
1516 (observer)(any_view, self);
1517 true
1518 });
1519
1520 view
1521 }
1522
1523 /// Update the given view. Prefer calling `View::update` instead, which calls this method.
1524 fn update_view<T: 'static, R>(
1525 &mut self,
1526 view: &View<T>,
1527 update: impl FnOnce(&mut T, &mut ViewContext<'_, T>) -> R,
1528 ) -> Self::Result<R> {
1529 let mut lease = self.app.entities.lease(&view.model);
1530 let mut cx = ViewContext::new(&mut *self.app, &mut *self.window, &view);
1531 let result = update(&mut *lease, &mut cx);
1532 cx.app.entities.end_lease(lease);
1533 result
1534 }
1535
1536 fn replace_root_view<V>(
1537 &mut self,
1538 build_view: impl FnOnce(&mut ViewContext<'_, V>) -> V,
1539 ) -> Self::Result<View<V>>
1540 where
1541 V: Render,
1542 {
1543 let slot = self.app.entities.reserve();
1544 let view = View {
1545 model: slot.clone(),
1546 };
1547 let mut cx = ViewContext::new(&mut *self.app, &mut *self.window, &view);
1548 let entity = build_view(&mut cx);
1549 self.entities.insert(slot, entity);
1550 self.window.root_view = Some(view.clone().into());
1551 view
1552 }
1553}
1554
1555impl<'a> std::ops::Deref for WindowContext<'a> {
1556 type Target = AppContext;
1557
1558 fn deref(&self) -> &Self::Target {
1559 &self.app
1560 }
1561}
1562
1563impl<'a> std::ops::DerefMut for WindowContext<'a> {
1564 fn deref_mut(&mut self) -> &mut Self::Target {
1565 &mut self.app
1566 }
1567}
1568
1569impl<'a> Borrow<AppContext> for WindowContext<'a> {
1570 fn borrow(&self) -> &AppContext {
1571 &self.app
1572 }
1573}
1574
1575impl<'a> BorrowMut<AppContext> for WindowContext<'a> {
1576 fn borrow_mut(&mut self) -> &mut AppContext {
1577 &mut self.app
1578 }
1579}
1580
1581pub trait BorrowWindow: BorrowMut<Window> + BorrowMut<AppContext> {
1582 fn app_mut(&mut self) -> &mut AppContext {
1583 self.borrow_mut()
1584 }
1585
1586 fn window(&self) -> &Window {
1587 self.borrow()
1588 }
1589
1590 fn window_mut(&mut self) -> &mut Window {
1591 self.borrow_mut()
1592 }
1593
1594 /// Pushes the given element id onto the global stack and invokes the given closure
1595 /// with a `GlobalElementId`, which disambiguates the given id in the context of its ancestor
1596 /// ids. Because elements are discarded and recreated on each frame, the `GlobalElementId` is
1597 /// used to associate state with identified elements across separate frames.
1598 fn with_element_id<R>(
1599 &mut self,
1600 id: Option<impl Into<ElementId>>,
1601 f: impl FnOnce(&mut Self) -> R,
1602 ) -> R {
1603 if let Some(id) = id.map(Into::into) {
1604 let window = self.window_mut();
1605 window.element_id_stack.push(id.into());
1606 let result = f(self);
1607 let window: &mut Window = self.borrow_mut();
1608 window.element_id_stack.pop();
1609 result
1610 } else {
1611 f(self)
1612 }
1613 }
1614
1615 /// Invoke the given function with the given content mask after intersecting it
1616 /// with the current mask.
1617 fn with_content_mask<R>(
1618 &mut self,
1619 mask: Option<ContentMask<Pixels>>,
1620 f: impl FnOnce(&mut Self) -> R,
1621 ) -> R {
1622 if let Some(mask) = mask {
1623 let mask = mask.intersect(&self.content_mask());
1624 self.window_mut()
1625 .current_frame
1626 .content_mask_stack
1627 .push(mask);
1628 let result = f(self);
1629 self.window_mut().current_frame.content_mask_stack.pop();
1630 result
1631 } else {
1632 f(self)
1633 }
1634 }
1635
1636 /// Update the global element offset based on the given offset. This is used to implement
1637 /// scrolling and position drag handles.
1638 fn with_element_offset<R>(
1639 &mut self,
1640 offset: Point<Pixels>,
1641 f: impl FnOnce(&mut Self) -> R,
1642 ) -> R {
1643 if offset.is_zero() {
1644 return f(self);
1645 };
1646
1647 let offset = self.element_offset() + offset;
1648 self.window_mut()
1649 .current_frame
1650 .element_offset_stack
1651 .push(offset);
1652 let result = f(self);
1653 self.window_mut().current_frame.element_offset_stack.pop();
1654 result
1655 }
1656
1657 /// Obtain the current element offset.
1658 fn element_offset(&self) -> Point<Pixels> {
1659 self.window()
1660 .current_frame
1661 .element_offset_stack
1662 .last()
1663 .copied()
1664 .unwrap_or_default()
1665 }
1666
1667 /// Update or intialize state for an element with the given id that lives across multiple
1668 /// frames. If an element with this id existed in the previous frame, its state will be passed
1669 /// to the given closure. The state returned by the closure will be stored so it can be referenced
1670 /// when drawing the next frame.
1671 fn with_element_state<S, R>(
1672 &mut self,
1673 id: ElementId,
1674 f: impl FnOnce(Option<S>, &mut Self) -> (R, S),
1675 ) -> R
1676 where
1677 S: 'static,
1678 {
1679 self.with_element_id(Some(id), |cx| {
1680 let global_id = cx.window().element_id_stack.clone();
1681
1682 if let Some(any) = cx
1683 .window_mut()
1684 .current_frame
1685 .element_states
1686 .remove(&global_id)
1687 .or_else(|| {
1688 cx.window_mut()
1689 .previous_frame
1690 .element_states
1691 .remove(&global_id)
1692 })
1693 {
1694 // Using the extra inner option to avoid needing to reallocate a new box.
1695 let mut state_box = any
1696 .downcast::<Option<S>>()
1697 .expect("invalid element state type for id");
1698 let state = state_box
1699 .take()
1700 .expect("element state is already on the stack");
1701 let (result, state) = f(Some(state), cx);
1702 state_box.replace(state);
1703 cx.window_mut()
1704 .current_frame
1705 .element_states
1706 .insert(global_id, state_box);
1707 result
1708 } else {
1709 let (result, state) = f(None, cx);
1710 cx.window_mut()
1711 .current_frame
1712 .element_states
1713 .insert(global_id, Box::new(Some(state)));
1714 result
1715 }
1716 })
1717 }
1718
1719 /// Like `with_element_state`, but for situations where the element_id is optional. If the
1720 /// id is `None`, no state will be retrieved or stored.
1721 fn with_optional_element_state<S, R>(
1722 &mut self,
1723 element_id: Option<ElementId>,
1724 f: impl FnOnce(Option<S>, &mut Self) -> (R, S),
1725 ) -> R
1726 where
1727 S: 'static,
1728 {
1729 if let Some(element_id) = element_id {
1730 self.with_element_state(element_id, f)
1731 } else {
1732 f(None, self).0
1733 }
1734 }
1735
1736 /// Obtain the current content mask.
1737 fn content_mask(&self) -> ContentMask<Pixels> {
1738 self.window()
1739 .current_frame
1740 .content_mask_stack
1741 .last()
1742 .cloned()
1743 .unwrap_or_else(|| ContentMask {
1744 bounds: Bounds {
1745 origin: Point::default(),
1746 size: self.window().viewport_size,
1747 },
1748 })
1749 }
1750
1751 /// The size of an em for the base font of the application. Adjusting this value allows the
1752 /// UI to scale, just like zooming a web page.
1753 fn rem_size(&self) -> Pixels {
1754 self.window().rem_size
1755 }
1756}
1757
1758impl Borrow<Window> for WindowContext<'_> {
1759 fn borrow(&self) -> &Window {
1760 &self.window
1761 }
1762}
1763
1764impl BorrowMut<Window> for WindowContext<'_> {
1765 fn borrow_mut(&mut self) -> &mut Window {
1766 &mut self.window
1767 }
1768}
1769
1770impl<T> BorrowWindow for T where T: BorrowMut<AppContext> + BorrowMut<Window> {}
1771
1772pub struct ViewContext<'a, V> {
1773 window_cx: WindowContext<'a>,
1774 view: &'a View<V>,
1775}
1776
1777impl<V> Borrow<AppContext> for ViewContext<'_, V> {
1778 fn borrow(&self) -> &AppContext {
1779 &*self.window_cx.app
1780 }
1781}
1782
1783impl<V> BorrowMut<AppContext> for ViewContext<'_, V> {
1784 fn borrow_mut(&mut self) -> &mut AppContext {
1785 &mut *self.window_cx.app
1786 }
1787}
1788
1789impl<V> Borrow<Window> for ViewContext<'_, V> {
1790 fn borrow(&self) -> &Window {
1791 &*self.window_cx.window
1792 }
1793}
1794
1795impl<V> BorrowMut<Window> for ViewContext<'_, V> {
1796 fn borrow_mut(&mut self) -> &mut Window {
1797 &mut *self.window_cx.window
1798 }
1799}
1800
1801impl<'a, V: 'static> ViewContext<'a, V> {
1802 pub(crate) fn new(app: &'a mut AppContext, window: &'a mut Window, view: &'a View<V>) -> Self {
1803 Self {
1804 window_cx: WindowContext::new(app, window),
1805 view,
1806 }
1807 }
1808
1809 pub fn entity_id(&self) -> EntityId {
1810 self.view.entity_id()
1811 }
1812
1813 pub fn view(&self) -> &View<V> {
1814 self.view
1815 }
1816
1817 pub fn model(&self) -> Model<V> {
1818 self.view.model.clone()
1819 }
1820
1821 /// Access the underlying window context.
1822 pub fn window_context(&mut self) -> &mut WindowContext<'a> {
1823 &mut self.window_cx
1824 }
1825
1826 pub fn with_z_index<R>(&mut self, z_index: u32, f: impl FnOnce(&mut Self) -> R) -> R {
1827 self.window.current_frame.z_index_stack.push(z_index);
1828 let result = f(self);
1829 self.window.current_frame.z_index_stack.pop();
1830 result
1831 }
1832
1833 pub fn on_next_frame(&mut self, f: impl FnOnce(&mut V, &mut ViewContext<V>) + 'static)
1834 where
1835 V: 'static,
1836 {
1837 let view = self.view().clone();
1838 self.window_cx.on_next_frame(move |cx| view.update(cx, f));
1839 }
1840
1841 /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
1842 /// that are currently on the stack to be returned to the app.
1843 pub fn defer(&mut self, f: impl FnOnce(&mut V, &mut ViewContext<V>) + 'static) {
1844 let view = self.view().downgrade();
1845 self.window_cx.defer(move |cx| {
1846 view.update(cx, f).ok();
1847 });
1848 }
1849
1850 pub fn observe<V2, E>(
1851 &mut self,
1852 entity: &E,
1853 mut on_notify: impl FnMut(&mut V, E, &mut ViewContext<'_, V>) + 'static,
1854 ) -> Subscription
1855 where
1856 V2: 'static,
1857 V: 'static,
1858 E: Entity<V2>,
1859 {
1860 let view = self.view().downgrade();
1861 let entity_id = entity.entity_id();
1862 let entity = entity.downgrade();
1863 let window_handle = self.window.handle;
1864 self.app.observers.insert(
1865 entity_id,
1866 Box::new(move |cx| {
1867 window_handle
1868 .update(cx, |_, cx| {
1869 if let Some(handle) = E::upgrade_from(&entity) {
1870 view.update(cx, |this, cx| on_notify(this, handle, cx))
1871 .is_ok()
1872 } else {
1873 false
1874 }
1875 })
1876 .unwrap_or(false)
1877 }),
1878 )
1879 }
1880
1881 pub fn subscribe<V2, E, Evt>(
1882 &mut self,
1883 entity: &E,
1884 mut on_event: impl FnMut(&mut V, E, &Evt, &mut ViewContext<'_, V>) + 'static,
1885 ) -> Subscription
1886 where
1887 V2: EventEmitter<Evt>,
1888 E: Entity<V2>,
1889 Evt: 'static,
1890 {
1891 let view = self.view().downgrade();
1892 let entity_id = entity.entity_id();
1893 let handle = entity.downgrade();
1894 let window_handle = self.window.handle;
1895 self.app.event_listeners.insert(
1896 entity_id,
1897 (
1898 TypeId::of::<Evt>(),
1899 Box::new(move |event, cx| {
1900 window_handle
1901 .update(cx, |_, cx| {
1902 if let Some(handle) = E::upgrade_from(&handle) {
1903 let event = event.downcast_ref().expect("invalid event type");
1904 view.update(cx, |this, cx| on_event(this, handle, event, cx))
1905 .is_ok()
1906 } else {
1907 false
1908 }
1909 })
1910 .unwrap_or(false)
1911 }),
1912 ),
1913 )
1914 }
1915
1916 pub fn on_release(
1917 &mut self,
1918 on_release: impl FnOnce(&mut V, &mut WindowContext) + 'static,
1919 ) -> Subscription {
1920 let window_handle = self.window.handle;
1921 self.app.release_listeners.insert(
1922 self.view.model.entity_id,
1923 Box::new(move |this, cx| {
1924 let this = this.downcast_mut().expect("invalid entity type");
1925 let _ = window_handle.update(cx, |_, cx| on_release(this, cx));
1926 }),
1927 )
1928 }
1929
1930 pub fn observe_release<V2, E>(
1931 &mut self,
1932 entity: &E,
1933 mut on_release: impl FnMut(&mut V, &mut V2, &mut ViewContext<'_, V>) + 'static,
1934 ) -> Subscription
1935 where
1936 V: 'static,
1937 V2: 'static,
1938 E: Entity<V2>,
1939 {
1940 let view = self.view().downgrade();
1941 let entity_id = entity.entity_id();
1942 let window_handle = self.window.handle;
1943 self.app.release_listeners.insert(
1944 entity_id,
1945 Box::new(move |entity, cx| {
1946 let entity = entity.downcast_mut().expect("invalid entity type");
1947 let _ = window_handle.update(cx, |_, cx| {
1948 view.update(cx, |this, cx| on_release(this, entity, cx))
1949 });
1950 }),
1951 )
1952 }
1953
1954 pub fn notify(&mut self) {
1955 self.window_cx.notify();
1956 self.window_cx.app.push_effect(Effect::Notify {
1957 emitter: self.view.model.entity_id,
1958 });
1959 }
1960
1961 pub fn observe_window_bounds(
1962 &mut self,
1963 mut callback: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
1964 ) -> Subscription {
1965 let view = self.view.downgrade();
1966 self.window.bounds_observers.insert(
1967 (),
1968 Box::new(move |cx| view.update(cx, |view, cx| callback(view, cx)).is_ok()),
1969 )
1970 }
1971
1972 pub fn observe_window_activation(
1973 &mut self,
1974 mut callback: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
1975 ) -> Subscription {
1976 let view = self.view.downgrade();
1977 self.window.activation_observers.insert(
1978 (),
1979 Box::new(move |cx| view.update(cx, |view, cx| callback(view, cx)).is_ok()),
1980 )
1981 }
1982
1983 /// Register a listener to be called when the given focus handle receives focus.
1984 /// Unlike [on_focus_changed], returns a subscription and persists until the subscription
1985 /// is dropped.
1986 pub fn on_focus(
1987 &mut self,
1988 handle: &FocusHandle,
1989 mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
1990 ) -> Subscription {
1991 let view = self.view.downgrade();
1992 let focus_id = handle.id;
1993 self.window.focus_listeners.insert(
1994 (),
1995 Box::new(move |event, cx| {
1996 view.update(cx, |view, cx| {
1997 if event.focused.as_ref().map(|focused| focused.id) == Some(focus_id) {
1998 listener(view, cx)
1999 }
2000 })
2001 .is_ok()
2002 }),
2003 )
2004 }
2005
2006 /// Register a listener to be called when the given focus handle or one of its descendants receives focus.
2007 /// Unlike [on_focus_changed], returns a subscription and persists until the subscription
2008 /// is dropped.
2009 pub fn on_focus_in(
2010 &mut self,
2011 handle: &FocusHandle,
2012 mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2013 ) -> Subscription {
2014 let view = self.view.downgrade();
2015 let focus_id = handle.id;
2016 self.window.focus_listeners.insert(
2017 (),
2018 Box::new(move |event, cx| {
2019 view.update(cx, |view, cx| {
2020 if event
2021 .focused
2022 .as_ref()
2023 .map_or(false, |focused| focus_id.contains(focused.id, cx))
2024 {
2025 listener(view, cx)
2026 }
2027 })
2028 .is_ok()
2029 }),
2030 )
2031 }
2032
2033 /// Register a listener to be called when the given focus handle loses focus.
2034 /// Unlike [on_focus_changed], returns a subscription and persists until the subscription
2035 /// is dropped.
2036 pub fn on_blur(
2037 &mut self,
2038 handle: &FocusHandle,
2039 mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2040 ) -> Subscription {
2041 let view = self.view.downgrade();
2042 let focus_id = handle.id;
2043 self.window.focus_listeners.insert(
2044 (),
2045 Box::new(move |event, cx| {
2046 view.update(cx, |view, cx| {
2047 if event.blurred.as_ref().map(|blurred| blurred.id) == Some(focus_id) {
2048 listener(view, cx)
2049 }
2050 })
2051 .is_ok()
2052 }),
2053 )
2054 }
2055
2056 /// Register a listener to be called when the given focus handle or one of its descendants loses focus.
2057 /// Unlike [on_focus_changed], returns a subscription and persists until the subscription
2058 /// is dropped.
2059 pub fn on_focus_out(
2060 &mut self,
2061 handle: &FocusHandle,
2062 mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2063 ) -> Subscription {
2064 let view = self.view.downgrade();
2065 let focus_id = handle.id;
2066 self.window.focus_listeners.insert(
2067 (),
2068 Box::new(move |event, cx| {
2069 view.update(cx, |view, cx| {
2070 if event
2071 .blurred
2072 .as_ref()
2073 .map_or(false, |blurred| focus_id.contains(blurred.id, cx))
2074 {
2075 listener(view, cx)
2076 }
2077 })
2078 .is_ok()
2079 }),
2080 )
2081 }
2082
2083 /// Register a focus listener for the current frame only. It will be cleared
2084 /// on the next frame render. You should use this method only from within elements,
2085 /// and we may want to enforce that better via a different context type.
2086 // todo!() Move this to `FrameContext` to emphasize its individuality?
2087 pub fn on_focus_changed(
2088 &mut self,
2089 listener: impl Fn(&mut V, &FocusEvent, &mut ViewContext<V>) + 'static,
2090 ) {
2091 let handle = self.view().downgrade();
2092 self.window
2093 .current_frame
2094 .focus_listeners
2095 .push(Box::new(move |event, cx| {
2096 handle
2097 .update(cx, |view, cx| listener(view, event, cx))
2098 .log_err();
2099 }));
2100 }
2101
2102 pub fn with_key_dispatch<R>(
2103 &mut self,
2104 context: KeyContext,
2105 focus_handle: Option<FocusHandle>,
2106 f: impl FnOnce(Option<FocusHandle>, &mut Self) -> R,
2107 ) -> R {
2108 let window = &mut self.window;
2109 window
2110 .current_frame
2111 .dispatch_tree
2112 .push_node(context.clone());
2113 if let Some(focus_handle) = focus_handle.as_ref() {
2114 window
2115 .current_frame
2116 .dispatch_tree
2117 .make_focusable(focus_handle.id);
2118 }
2119 let result = f(focus_handle, self);
2120
2121 self.window.current_frame.dispatch_tree.pop_node();
2122
2123 result
2124 }
2125
2126 pub fn spawn<Fut, R>(
2127 &mut self,
2128 f: impl FnOnce(WeakView<V>, AsyncWindowContext) -> Fut,
2129 ) -> Task<R>
2130 where
2131 R: 'static,
2132 Fut: Future<Output = R> + 'static,
2133 {
2134 let view = self.view().downgrade();
2135 self.window_cx.spawn(|cx| f(view, cx))
2136 }
2137
2138 pub fn update_global<G, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R
2139 where
2140 G: 'static,
2141 {
2142 let mut global = self.app.lease_global::<G>();
2143 let result = f(&mut global, self);
2144 self.app.end_global_lease(global);
2145 result
2146 }
2147
2148 pub fn observe_global<G: 'static>(
2149 &mut self,
2150 f: impl Fn(&mut V, &mut ViewContext<'_, V>) + 'static,
2151 ) -> Subscription {
2152 let window_handle = self.window.handle;
2153 let view = self.view().downgrade();
2154 self.global_observers.insert(
2155 TypeId::of::<G>(),
2156 Box::new(move |cx| {
2157 window_handle
2158 .update(cx, |_, cx| view.update(cx, |view, cx| f(view, cx)).is_ok())
2159 .unwrap_or(false)
2160 }),
2161 )
2162 }
2163
2164 pub fn on_mouse_event<Event: 'static>(
2165 &mut self,
2166 handler: impl Fn(&mut V, &Event, DispatchPhase, &mut ViewContext<V>) + 'static,
2167 ) {
2168 let handle = self.view().clone();
2169 self.window_cx.on_mouse_event(move |event, phase, cx| {
2170 handle.update(cx, |view, cx| {
2171 handler(view, event, phase, cx);
2172 })
2173 });
2174 }
2175
2176 pub fn on_key_event<Event: 'static>(
2177 &mut self,
2178 handler: impl Fn(&mut V, &Event, DispatchPhase, &mut ViewContext<V>) + 'static,
2179 ) {
2180 let handle = self.view().clone();
2181 self.window_cx.on_key_event(move |event, phase, cx| {
2182 handle.update(cx, |view, cx| {
2183 handler(view, event, phase, cx);
2184 })
2185 });
2186 }
2187
2188 pub fn on_action(
2189 &mut self,
2190 action_type: TypeId,
2191 handler: impl Fn(&mut V, &dyn Any, DispatchPhase, &mut ViewContext<V>) + 'static,
2192 ) {
2193 let handle = self.view().clone();
2194 self.window_cx
2195 .on_action(action_type, move |action, phase, cx| {
2196 handle.update(cx, |view, cx| {
2197 handler(view, action, phase, cx);
2198 })
2199 });
2200 }
2201
2202 /// Set an input handler, such as [ElementInputHandler], which interfaces with the
2203 /// platform to receive textual input with proper integration with concerns such
2204 /// as IME interactions.
2205 pub fn handle_input(
2206 &mut self,
2207 focus_handle: &FocusHandle,
2208 input_handler: impl PlatformInputHandler,
2209 ) {
2210 if focus_handle.is_focused(self) {
2211 self.window
2212 .platform_window
2213 .set_input_handler(Box::new(input_handler));
2214 }
2215 }
2216}
2217
2218impl<V> ViewContext<'_, V> {
2219 pub fn emit<Evt>(&mut self, event: Evt)
2220 where
2221 Evt: 'static,
2222 V: EventEmitter<Evt>,
2223 {
2224 let emitter = self.view.model.entity_id;
2225 self.app.push_effect(Effect::Emit {
2226 emitter,
2227 event_type: TypeId::of::<Evt>(),
2228 event: Box::new(event),
2229 });
2230 }
2231}
2232
2233impl<V> Context for ViewContext<'_, V> {
2234 type Result<U> = U;
2235
2236 fn build_model<T: 'static>(
2237 &mut self,
2238 build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
2239 ) -> Model<T> {
2240 self.window_cx.build_model(build_model)
2241 }
2242
2243 fn update_model<T: 'static, R>(
2244 &mut self,
2245 model: &Model<T>,
2246 update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
2247 ) -> R {
2248 self.window_cx.update_model(model, update)
2249 }
2250
2251 fn update_window<T, F>(&mut self, window: AnyWindowHandle, update: F) -> Result<T>
2252 where
2253 F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
2254 {
2255 self.window_cx.update_window(window, update)
2256 }
2257
2258 fn read_model<T, R>(
2259 &self,
2260 handle: &Model<T>,
2261 read: impl FnOnce(&T, &AppContext) -> R,
2262 ) -> Self::Result<R>
2263 where
2264 T: 'static,
2265 {
2266 self.window_cx.read_model(handle, read)
2267 }
2268
2269 fn read_window<T, R>(
2270 &self,
2271 window: &WindowHandle<T>,
2272 read: impl FnOnce(View<T>, &AppContext) -> R,
2273 ) -> Result<R>
2274 where
2275 T: 'static,
2276 {
2277 self.window_cx.read_window(window, read)
2278 }
2279}
2280
2281impl<V: 'static> VisualContext for ViewContext<'_, V> {
2282 fn build_view<W: Render + 'static>(
2283 &mut self,
2284 build_view_state: impl FnOnce(&mut ViewContext<'_, W>) -> W,
2285 ) -> Self::Result<View<W>> {
2286 self.window_cx.build_view(build_view_state)
2287 }
2288
2289 fn update_view<V2: 'static, R>(
2290 &mut self,
2291 view: &View<V2>,
2292 update: impl FnOnce(&mut V2, &mut ViewContext<'_, V2>) -> R,
2293 ) -> Self::Result<R> {
2294 self.window_cx.update_view(view, update)
2295 }
2296
2297 fn replace_root_view<W>(
2298 &mut self,
2299 build_view: impl FnOnce(&mut ViewContext<'_, W>) -> W,
2300 ) -> Self::Result<View<W>>
2301 where
2302 W: Render,
2303 {
2304 self.window_cx.replace_root_view(build_view)
2305 }
2306}
2307
2308impl<'a, V> std::ops::Deref for ViewContext<'a, V> {
2309 type Target = WindowContext<'a>;
2310
2311 fn deref(&self) -> &Self::Target {
2312 &self.window_cx
2313 }
2314}
2315
2316impl<'a, V> std::ops::DerefMut for ViewContext<'a, V> {
2317 fn deref_mut(&mut self) -> &mut Self::Target {
2318 &mut self.window_cx
2319 }
2320}
2321
2322// #[derive(Clone, Copy, Eq, PartialEq, Hash)]
2323slotmap::new_key_type! { pub struct WindowId; }
2324
2325impl WindowId {
2326 pub fn as_u64(&self) -> u64 {
2327 self.0.as_ffi()
2328 }
2329}
2330
2331#[derive(Deref, DerefMut)]
2332pub struct WindowHandle<V> {
2333 #[deref]
2334 #[deref_mut]
2335 pub(crate) any_handle: AnyWindowHandle,
2336 state_type: PhantomData<V>,
2337}
2338
2339impl<V: 'static + Render> WindowHandle<V> {
2340 pub fn new(id: WindowId) -> Self {
2341 WindowHandle {
2342 any_handle: AnyWindowHandle {
2343 id,
2344 state_type: TypeId::of::<V>(),
2345 },
2346 state_type: PhantomData,
2347 }
2348 }
2349
2350 pub fn update<C, R>(
2351 &self,
2352 cx: &mut C,
2353 update: impl FnOnce(&mut V, &mut ViewContext<'_, V>) -> R,
2354 ) -> Result<R>
2355 where
2356 C: Context,
2357 {
2358 cx.update_window(self.any_handle, |root_view, cx| {
2359 let view = root_view
2360 .downcast::<V>()
2361 .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
2362 Ok(cx.update_view(&view, update))
2363 })?
2364 }
2365
2366 pub fn read<'a>(&self, cx: &'a AppContext) -> Result<&'a V> {
2367 let x = cx
2368 .windows
2369 .get(self.id)
2370 .and_then(|window| {
2371 window
2372 .as_ref()
2373 .and_then(|window| window.root_view.clone())
2374 .map(|root_view| root_view.downcast::<V>())
2375 })
2376 .ok_or_else(|| anyhow!("window not found"))?
2377 .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
2378
2379 Ok(x.read(cx))
2380 }
2381
2382 pub fn read_with<C, R>(&self, cx: &C, read_with: impl FnOnce(&V, &AppContext) -> R) -> Result<R>
2383 where
2384 C: Context,
2385 {
2386 cx.read_window(self, |root_view, cx| read_with(root_view.read(cx), cx))
2387 }
2388
2389 pub fn root_view<C>(&self, cx: &C) -> Result<View<V>>
2390 where
2391 C: Context,
2392 {
2393 cx.read_window(self, |root_view, _cx| root_view.clone())
2394 }
2395
2396 pub fn is_active(&self, cx: &WindowContext) -> Option<bool> {
2397 cx.windows
2398 .get(self.id)
2399 .and_then(|window| window.as_ref().map(|window| window.active))
2400 }
2401}
2402
2403impl<V> Copy for WindowHandle<V> {}
2404
2405impl<V> Clone for WindowHandle<V> {
2406 fn clone(&self) -> Self {
2407 WindowHandle {
2408 any_handle: self.any_handle,
2409 state_type: PhantomData,
2410 }
2411 }
2412}
2413
2414impl<V> PartialEq for WindowHandle<V> {
2415 fn eq(&self, other: &Self) -> bool {
2416 self.any_handle == other.any_handle
2417 }
2418}
2419
2420impl<V> Eq for WindowHandle<V> {}
2421
2422impl<V> Hash for WindowHandle<V> {
2423 fn hash<H: Hasher>(&self, state: &mut H) {
2424 self.any_handle.hash(state);
2425 }
2426}
2427
2428impl<V: 'static> Into<AnyWindowHandle> for WindowHandle<V> {
2429 fn into(self) -> AnyWindowHandle {
2430 self.any_handle
2431 }
2432}
2433
2434#[derive(Copy, Clone, PartialEq, Eq, Hash)]
2435pub struct AnyWindowHandle {
2436 pub(crate) id: WindowId,
2437 state_type: TypeId,
2438}
2439
2440impl AnyWindowHandle {
2441 pub fn window_id(&self) -> WindowId {
2442 self.id
2443 }
2444
2445 pub fn downcast<T: 'static>(&self) -> Option<WindowHandle<T>> {
2446 if TypeId::of::<T>() == self.state_type {
2447 Some(WindowHandle {
2448 any_handle: *self,
2449 state_type: PhantomData,
2450 })
2451 } else {
2452 None
2453 }
2454 }
2455
2456 pub fn update<C, R>(
2457 self,
2458 cx: &mut C,
2459 update: impl FnOnce(AnyView, &mut WindowContext<'_>) -> R,
2460 ) -> Result<R>
2461 where
2462 C: Context,
2463 {
2464 cx.update_window(self, update)
2465 }
2466
2467 pub fn read<T, C, R>(self, cx: &C, read: impl FnOnce(View<T>, &AppContext) -> R) -> Result<R>
2468 where
2469 C: Context,
2470 T: 'static,
2471 {
2472 let view = self
2473 .downcast::<T>()
2474 .context("the type of the window's root view has changed")?;
2475
2476 cx.read_window(&view, read)
2477 }
2478}
2479
2480#[cfg(any(test, feature = "test-support"))]
2481impl From<SmallVec<[u32; 16]>> for StackingOrder {
2482 fn from(small_vec: SmallVec<[u32; 16]>) -> Self {
2483 StackingOrder(small_vec)
2484 }
2485}
2486
2487#[derive(Clone, Debug, Eq, PartialEq, Hash)]
2488pub enum ElementId {
2489 View(EntityId),
2490 Integer(usize),
2491 Name(SharedString),
2492 FocusHandle(FocusId),
2493}
2494
2495impl From<EntityId> for ElementId {
2496 fn from(id: EntityId) -> Self {
2497 ElementId::View(id)
2498 }
2499}
2500
2501impl From<usize> for ElementId {
2502 fn from(id: usize) -> Self {
2503 ElementId::Integer(id)
2504 }
2505}
2506
2507impl From<i32> for ElementId {
2508 fn from(id: i32) -> Self {
2509 Self::Integer(id as usize)
2510 }
2511}
2512
2513impl From<SharedString> for ElementId {
2514 fn from(name: SharedString) -> Self {
2515 ElementId::Name(name)
2516 }
2517}
2518
2519impl From<&'static str> for ElementId {
2520 fn from(name: &'static str) -> Self {
2521 ElementId::Name(name.into())
2522 }
2523}
2524
2525impl<'a> From<&'a FocusHandle> for ElementId {
2526 fn from(handle: &'a FocusHandle) -> Self {
2527 ElementId::FocusHandle(handle.id)
2528 }
2529}