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
188pub trait FocusableView: Render {
189 fn focus_handle(&self, cx: &AppContext) -> FocusHandle;
190}
191
192// Holds the state for a specific window.
193pub struct Window {
194 pub(crate) handle: AnyWindowHandle,
195 pub(crate) removed: bool,
196 pub(crate) platform_window: Box<dyn PlatformWindow>,
197 display_id: DisplayId,
198 sprite_atlas: Arc<dyn PlatformAtlas>,
199 rem_size: Pixels,
200 viewport_size: Size<Pixels>,
201 pub(crate) layout_engine: TaffyLayoutEngine,
202 pub(crate) root_view: Option<AnyView>,
203 pub(crate) element_id_stack: GlobalElementId,
204 pub(crate) previous_frame: Frame,
205 pub(crate) current_frame: Frame,
206 pub(crate) focus_handles: Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>,
207 pub(crate) focus_listeners: SubscriberSet<(), AnyWindowFocusListener>,
208 default_prevented: bool,
209 mouse_position: Point<Pixels>,
210 requested_cursor_style: Option<CursorStyle>,
211 scale_factor: f32,
212 bounds: WindowBounds,
213 bounds_observers: SubscriberSet<(), AnyObserver>,
214 active: bool,
215 activation_observers: SubscriberSet<(), AnyObserver>,
216 pub(crate) dirty: bool,
217 pub(crate) last_blur: Option<Option<FocusId>>,
218 pub(crate) focus: Option<FocusId>,
219}
220
221// #[derive(Default)]
222pub(crate) struct Frame {
223 pub(crate) element_states: HashMap<GlobalElementId, AnyBox>,
224 mouse_listeners: HashMap<TypeId, Vec<(StackingOrder, AnyMouseListener)>>,
225 pub(crate) dispatch_tree: DispatchTree,
226 pub(crate) focus_listeners: Vec<AnyFocusListener>,
227 pub(crate) scene_builder: SceneBuilder,
228 z_index_stack: StackingOrder,
229 content_mask_stack: Vec<ContentMask<Pixels>>,
230 element_offset_stack: Vec<Point<Pixels>>,
231}
232
233impl Frame {
234 pub fn new(dispatch_tree: DispatchTree) -> Self {
235 Frame {
236 element_states: HashMap::default(),
237 mouse_listeners: HashMap::default(),
238 dispatch_tree,
239 focus_listeners: Vec::new(),
240 scene_builder: SceneBuilder::default(),
241 z_index_stack: StackingOrder::default(),
242 content_mask_stack: Vec::new(),
243 element_offset_stack: Vec::new(),
244 }
245 }
246}
247
248impl Window {
249 pub(crate) fn new(
250 handle: AnyWindowHandle,
251 options: WindowOptions,
252 cx: &mut AppContext,
253 ) -> Self {
254 let platform_window = cx.platform.open_window(handle, options);
255 let display_id = platform_window.display().id();
256 let sprite_atlas = platform_window.sprite_atlas();
257 let mouse_position = platform_window.mouse_position();
258 let content_size = platform_window.content_size();
259 let scale_factor = platform_window.scale_factor();
260 let bounds = platform_window.bounds();
261
262 platform_window.on_resize(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_moved(Box::new({
271 let mut cx = cx.to_async();
272 move || {
273 handle
274 .update(&mut cx, |_, cx| cx.window_bounds_changed())
275 .log_err();
276 }
277 }));
278 platform_window.on_active_status_change(Box::new({
279 let mut cx = cx.to_async();
280 move |active| {
281 handle
282 .update(&mut cx, |_, cx| {
283 cx.window.active = active;
284 cx.window
285 .activation_observers
286 .clone()
287 .retain(&(), |callback| callback(cx));
288 })
289 .log_err();
290 }
291 }));
292
293 platform_window.on_input({
294 let mut cx = cx.to_async();
295 Box::new(move |event| {
296 handle
297 .update(&mut cx, |_, cx| cx.dispatch_event(event))
298 .log_err()
299 .unwrap_or(false)
300 })
301 });
302
303 Window {
304 handle,
305 removed: false,
306 platform_window,
307 display_id,
308 sprite_atlas,
309 rem_size: px(16.),
310 viewport_size: content_size,
311 layout_engine: TaffyLayoutEngine::new(),
312 root_view: None,
313 element_id_stack: GlobalElementId::default(),
314 previous_frame: Frame::new(DispatchTree::new(cx.keymap.clone())),
315 current_frame: Frame::new(DispatchTree::new(cx.keymap.clone())),
316 focus_handles: Arc::new(RwLock::new(SlotMap::with_key())),
317 focus_listeners: SubscriberSet::new(),
318 default_prevented: true,
319 mouse_position,
320 requested_cursor_style: None,
321 scale_factor,
322 bounds,
323 bounds_observers: SubscriberSet::new(),
324 active: false,
325 activation_observers: SubscriberSet::new(),
326 dirty: true,
327 last_blur: None,
328 focus: None,
329 }
330 }
331}
332
333/// Indicates which region of the window is visible. Content falling outside of this mask will not be
334/// rendered. Currently, only rectangular content masks are supported, but we give the mask its own type
335/// to leave room to support more complex shapes in the future.
336#[derive(Clone, Debug, Default, PartialEq, Eq)]
337#[repr(C)]
338pub struct ContentMask<P: Clone + Default + Debug> {
339 pub bounds: Bounds<P>,
340}
341
342impl ContentMask<Pixels> {
343 /// Scale the content mask's pixel units by the given scaling factor.
344 pub fn scale(&self, factor: f32) -> ContentMask<ScaledPixels> {
345 ContentMask {
346 bounds: self.bounds.scale(factor),
347 }
348 }
349
350 /// Intersect the content mask with the given content mask.
351 pub fn intersect(&self, other: &Self) -> Self {
352 let bounds = self.bounds.intersect(&other.bounds);
353 ContentMask { bounds }
354 }
355}
356
357/// Provides access to application state in the context of a single window. Derefs
358/// to an `AppContext`, so you can also pass a `WindowContext` to any method that takes
359/// an `AppContext` and call any `AppContext` methods.
360pub struct WindowContext<'a> {
361 pub(crate) app: &'a mut AppContext,
362 pub(crate) window: &'a mut Window,
363}
364
365impl<'a> WindowContext<'a> {
366 pub(crate) fn new(app: &'a mut AppContext, window: &'a mut Window) -> Self {
367 Self { app, window }
368 }
369
370 /// Obtain a handle to the window that belongs to this context.
371 pub fn window_handle(&self) -> AnyWindowHandle {
372 self.window.handle
373 }
374
375 /// Mark the window as dirty, scheduling it to be redrawn on the next frame.
376 pub fn notify(&mut self) {
377 self.window.dirty = true;
378 }
379
380 /// Close this window.
381 pub fn remove_window(&mut self) {
382 self.window.removed = true;
383 }
384
385 /// Obtain a new `FocusHandle`, which allows you to track and manipulate the keyboard focus
386 /// for elements rendered within this window.
387 pub fn focus_handle(&mut self) -> FocusHandle {
388 FocusHandle::new(&self.window.focus_handles)
389 }
390
391 /// Obtain the currently focused `FocusHandle`. If no elements are focused, returns `None`.
392 pub fn focused(&self) -> Option<FocusHandle> {
393 self.window
394 .focus
395 .and_then(|id| FocusHandle::for_id(id, &self.window.focus_handles))
396 }
397
398 /// Move focus to the element associated with the given `FocusHandle`.
399 pub fn focus(&mut self, handle: &FocusHandle) {
400 if self.window.focus == Some(handle.id) {
401 return;
402 }
403
404 let focus_id = handle.id;
405
406 if self.window.last_blur.is_none() {
407 self.window.last_blur = Some(self.window.focus);
408 }
409
410 self.window.focus = Some(focus_id);
411 self.window
412 .current_frame
413 .dispatch_tree
414 .clear_keystroke_matchers();
415 self.app.push_effect(Effect::FocusChanged {
416 window_handle: self.window.handle,
417 focused: Some(focus_id),
418 });
419 self.notify();
420 }
421
422 /// Remove focus from all elements within this context's window.
423 pub fn blur(&mut self) {
424 if self.window.last_blur.is_none() {
425 self.window.last_blur = Some(self.window.focus);
426 }
427
428 self.window.focus = None;
429 self.app.push_effect(Effect::FocusChanged {
430 window_handle: self.window.handle,
431 focused: None,
432 });
433 self.notify();
434 }
435
436 pub fn dispatch_action(&mut self, action: Box<dyn Action>) {
437 if let Some(focus_handle) = self.focused() {
438 self.defer(move |cx| {
439 if let Some(node_id) = cx
440 .window
441 .current_frame
442 .dispatch_tree
443 .focusable_node_id(focus_handle.id)
444 {
445 cx.propagate_event = true;
446 cx.dispatch_action_on_node(node_id, action);
447 }
448 })
449 }
450 }
451
452 /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
453 /// that are currently on the stack to be returned to the app.
454 pub fn defer(&mut self, f: impl FnOnce(&mut WindowContext) + 'static) {
455 let handle = self.window.handle;
456 self.app.defer(move |cx| {
457 handle.update(cx, |_, cx| f(cx)).ok();
458 });
459 }
460
461 pub fn subscribe<Emitter, E, Evt>(
462 &mut self,
463 entity: &E,
464 mut on_event: impl FnMut(E, &Evt, &mut WindowContext<'_>) + 'static,
465 ) -> Subscription
466 where
467 Emitter: EventEmitter<Evt>,
468 E: Entity<Emitter>,
469 Evt: 'static,
470 {
471 let entity_id = entity.entity_id();
472 let entity = entity.downgrade();
473 let window_handle = self.window.handle;
474 self.app.event_listeners.insert(
475 entity_id,
476 (
477 TypeId::of::<Evt>(),
478 Box::new(move |event, cx| {
479 window_handle
480 .update(cx, |_, cx| {
481 if let Some(handle) = E::upgrade_from(&entity) {
482 let event = event.downcast_ref().expect("invalid event type");
483 on_event(handle, event, cx);
484 true
485 } else {
486 false
487 }
488 })
489 .unwrap_or(false)
490 }),
491 ),
492 )
493 }
494
495 /// Create an `AsyncWindowContext`, which has a static lifetime and can be held across
496 /// await points in async code.
497 pub fn to_async(&self) -> AsyncWindowContext {
498 AsyncWindowContext::new(self.app.to_async(), self.window.handle)
499 }
500
501 /// Schedule the given closure to be run directly after the current frame is rendered.
502 pub fn on_next_frame(&mut self, callback: impl FnOnce(&mut WindowContext) + 'static) {
503 let handle = self.window.handle;
504 let display_id = self.window.display_id;
505
506 if !self.frame_consumers.contains_key(&display_id) {
507 let (tx, mut rx) = mpsc::unbounded::<()>();
508 self.platform.set_display_link_output_callback(
509 display_id,
510 Box::new(move |_current_time, _output_time| _ = tx.unbounded_send(())),
511 );
512
513 let consumer_task = self.app.spawn(|cx| async move {
514 while rx.next().await.is_some() {
515 cx.update(|cx| {
516 for callback in cx
517 .next_frame_callbacks
518 .get_mut(&display_id)
519 .unwrap()
520 .drain(..)
521 .collect::<SmallVec<[_; 32]>>()
522 {
523 callback(cx);
524 }
525 })
526 .ok();
527
528 // Flush effects, then stop the display link if no new next_frame_callbacks have been added.
529
530 cx.update(|cx| {
531 if cx.next_frame_callbacks.is_empty() {
532 cx.platform.stop_display_link(display_id);
533 }
534 })
535 .ok();
536 }
537 });
538 self.frame_consumers.insert(display_id, consumer_task);
539 }
540
541 if self.next_frame_callbacks.is_empty() {
542 self.platform.start_display_link(display_id);
543 }
544
545 self.next_frame_callbacks
546 .entry(display_id)
547 .or_default()
548 .push(Box::new(move |cx: &mut AppContext| {
549 cx.update_window(handle, |_root_view, cx| callback(cx)).ok();
550 }));
551 }
552
553 /// Spawn the future returned by the given closure on the application thread pool.
554 /// The closure is provided a handle to the current window and an `AsyncWindowContext` for
555 /// use within your future.
556 pub fn spawn<Fut, R>(&mut self, f: impl FnOnce(AsyncWindowContext) -> Fut) -> Task<R>
557 where
558 R: 'static,
559 Fut: Future<Output = R> + 'static,
560 {
561 self.app
562 .spawn(|app| f(AsyncWindowContext::new(app, self.window.handle)))
563 }
564
565 /// Update the global of the given type. The given closure is given simultaneous mutable
566 /// access both to the global and the context.
567 pub fn update_global<G, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R
568 where
569 G: 'static,
570 {
571 let mut global = self.app.lease_global::<G>();
572 let result = f(&mut global, self);
573 self.app.end_global_lease(global);
574 result
575 }
576
577 /// Add a node to the layout tree for the current frame. Takes the `Style` of the element for which
578 /// layout is being requested, along with the layout ids of any children. This method is called during
579 /// calls to the `Element::layout` trait method and enables any element to participate in layout.
580 pub fn request_layout(
581 &mut self,
582 style: &Style,
583 children: impl IntoIterator<Item = LayoutId>,
584 ) -> LayoutId {
585 self.app.layout_id_buffer.clear();
586 self.app.layout_id_buffer.extend(children.into_iter());
587 let rem_size = self.rem_size();
588
589 self.window
590 .layout_engine
591 .request_layout(style, rem_size, &self.app.layout_id_buffer)
592 }
593
594 /// Add a node to the layout tree for the current frame. Instead of taking a `Style` and children,
595 /// this variant takes a function that is invoked during layout so you can use arbitrary logic to
596 /// determine the element's size. One place this is used internally is when measuring text.
597 ///
598 /// The given closure is invoked at layout time with the known dimensions and available space and
599 /// returns a `Size`.
600 pub fn request_measured_layout<
601 F: Fn(Size<Option<Pixels>>, Size<AvailableSpace>) -> Size<Pixels> + Send + Sync + 'static,
602 >(
603 &mut self,
604 style: Style,
605 rem_size: Pixels,
606 measure: F,
607 ) -> LayoutId {
608 self.window
609 .layout_engine
610 .request_measured_layout(style, rem_size, measure)
611 }
612
613 pub fn compute_layout(&mut self, layout_id: LayoutId, available_space: Size<AvailableSpace>) {
614 self.window
615 .layout_engine
616 .compute_layout(layout_id, available_space)
617 }
618
619 /// Obtain the bounds computed for the given LayoutId relative to the window. This method should not
620 /// be invoked until the paint phase begins, and will usually be invoked by GPUI itself automatically
621 /// in order to pass your element its `Bounds` automatically.
622 pub fn layout_bounds(&mut self, layout_id: LayoutId) -> Bounds<Pixels> {
623 let mut bounds = self
624 .window
625 .layout_engine
626 .layout_bounds(layout_id)
627 .map(Into::into);
628 bounds.origin += self.element_offset();
629 bounds
630 }
631
632 fn window_bounds_changed(&mut self) {
633 self.window.scale_factor = self.window.platform_window.scale_factor();
634 self.window.viewport_size = self.window.platform_window.content_size();
635 self.window.bounds = self.window.platform_window.bounds();
636 self.window.display_id = self.window.platform_window.display().id();
637 self.window.dirty = true;
638
639 self.window
640 .bounds_observers
641 .clone()
642 .retain(&(), |callback| callback(self));
643 }
644
645 pub fn window_bounds(&self) -> WindowBounds {
646 self.window.bounds
647 }
648
649 pub fn viewport_size(&self) -> Size<Pixels> {
650 self.window.viewport_size
651 }
652
653 pub fn is_window_active(&self) -> bool {
654 self.window.active
655 }
656
657 pub fn zoom_window(&self) {
658 self.window.platform_window.zoom();
659 }
660
661 pub fn display(&self) -> Option<Rc<dyn PlatformDisplay>> {
662 self.platform
663 .displays()
664 .into_iter()
665 .find(|display| display.id() == self.window.display_id)
666 }
667
668 pub fn show_character_palette(&self) {
669 self.window.platform_window.show_character_palette();
670 }
671
672 /// The scale factor of the display associated with the window. For example, it could
673 /// return 2.0 for a "retina" display, indicating that each logical pixel should actually
674 /// be rendered as two pixels on screen.
675 pub fn scale_factor(&self) -> f32 {
676 self.window.scale_factor
677 }
678
679 /// The size of an em for the base font of the application. Adjusting this value allows the
680 /// UI to scale, just like zooming a web page.
681 pub fn rem_size(&self) -> Pixels {
682 self.window.rem_size
683 }
684
685 /// Sets the size of an em for the base font of the application. Adjusting this value allows the
686 /// UI to scale, just like zooming a web page.
687 pub fn set_rem_size(&mut self, rem_size: impl Into<Pixels>) {
688 self.window.rem_size = rem_size.into();
689 }
690
691 /// The line height associated with the current text style.
692 pub fn line_height(&self) -> Pixels {
693 let rem_size = self.rem_size();
694 let text_style = self.text_style();
695 text_style
696 .line_height
697 .to_pixels(text_style.font_size.into(), rem_size)
698 }
699
700 /// Call to prevent the default action of an event. Currently only used to prevent
701 /// parent elements from becoming focused on mouse down.
702 pub fn prevent_default(&mut self) {
703 self.window.default_prevented = true;
704 }
705
706 /// Obtain whether default has been prevented for the event currently being dispatched.
707 pub fn default_prevented(&self) -> bool {
708 self.window.default_prevented
709 }
710
711 /// Register a mouse event listener on the window for the current frame. The type of event
712 /// is determined by the first parameter of the given listener. When the next frame is rendered
713 /// the listener will be cleared.
714 ///
715 /// This is a fairly low-level method, so prefer using event handlers on elements unless you have
716 /// a specific need to register a global listener.
717 pub fn on_mouse_event<Event: 'static>(
718 &mut self,
719 handler: impl Fn(&Event, DispatchPhase, &mut WindowContext) + 'static,
720 ) {
721 let order = self.window.current_frame.z_index_stack.clone();
722 self.window
723 .current_frame
724 .mouse_listeners
725 .entry(TypeId::of::<Event>())
726 .or_default()
727 .push((
728 order,
729 Box::new(move |event: &dyn Any, phase, cx| {
730 handler(event.downcast_ref().unwrap(), phase, cx)
731 }),
732 ))
733 }
734
735 /// Register a key event listener on the window for the current frame. The type of event
736 /// is determined by the first parameter of the given listener. When the next frame is rendered
737 /// the listener will be cleared.
738 ///
739 /// This is a fairly low-level method, so prefer using event handlers on elements unless you have
740 /// a specific need to register a global listener.
741 pub fn on_key_event<Event: 'static>(
742 &mut self,
743 handler: impl Fn(&Event, DispatchPhase, &mut WindowContext) + 'static,
744 ) {
745 self.window
746 .current_frame
747 .dispatch_tree
748 .on_key_event(Rc::new(move |event, phase, cx| {
749 if let Some(event) = event.downcast_ref::<Event>() {
750 handler(event, phase, cx)
751 }
752 }));
753 }
754
755 /// Register an action listener on the window for the current frame. The type of action
756 /// is determined by the first parameter of the given listener. When the next frame is rendered
757 /// the listener will be cleared.
758 ///
759 /// This is a fairly low-level method, so prefer using action handlers on elements unless you have
760 /// a specific need to register a global listener.
761 pub fn on_action(
762 &mut self,
763 action_type: TypeId,
764 handler: impl Fn(&dyn Any, DispatchPhase, &mut WindowContext) + 'static,
765 ) {
766 self.window.current_frame.dispatch_tree.on_action(
767 action_type,
768 Rc::new(move |action, phase, cx| handler(action, phase, cx)),
769 );
770 }
771
772 /// The position of the mouse relative to the window.
773 pub fn mouse_position(&self) -> Point<Pixels> {
774 self.window.mouse_position
775 }
776
777 pub fn set_cursor_style(&mut self, style: CursorStyle) {
778 self.window.requested_cursor_style = Some(style)
779 }
780
781 /// Called during painting to invoke the given closure in a new stacking context. The given
782 /// z-index is interpreted relative to the previous call to `stack`.
783 pub fn with_z_index<R>(&mut self, z_index: u32, f: impl FnOnce(&mut Self) -> R) -> R {
784 self.window.current_frame.z_index_stack.push(z_index);
785 let result = f(self);
786 self.window.current_frame.z_index_stack.pop();
787 result
788 }
789
790 /// Paint one or more drop shadows into the scene for the current frame at the current z-index.
791 pub fn paint_shadows(
792 &mut self,
793 bounds: Bounds<Pixels>,
794 corner_radii: Corners<Pixels>,
795 shadows: &[BoxShadow],
796 ) {
797 let scale_factor = self.scale_factor();
798 let content_mask = self.content_mask();
799 let window = &mut *self.window;
800 for shadow in shadows {
801 let mut shadow_bounds = bounds;
802 shadow_bounds.origin += shadow.offset;
803 shadow_bounds.dilate(shadow.spread_radius);
804 window.current_frame.scene_builder.insert(
805 &window.current_frame.z_index_stack,
806 Shadow {
807 order: 0,
808 bounds: shadow_bounds.scale(scale_factor),
809 content_mask: content_mask.scale(scale_factor),
810 corner_radii: corner_radii.scale(scale_factor),
811 color: shadow.color,
812 blur_radius: shadow.blur_radius.scale(scale_factor),
813 },
814 );
815 }
816 }
817
818 /// Paint one or more quads into the scene for the current frame at the current stacking context.
819 /// Quads are colored rectangular regions with an optional background, border, and corner radius.
820 pub fn paint_quad(
821 &mut self,
822 bounds: Bounds<Pixels>,
823 corner_radii: Corners<Pixels>,
824 background: impl Into<Hsla>,
825 border_widths: Edges<Pixels>,
826 border_color: impl Into<Hsla>,
827 ) {
828 let scale_factor = self.scale_factor();
829 let content_mask = self.content_mask();
830
831 let window = &mut *self.window;
832 window.current_frame.scene_builder.insert(
833 &window.current_frame.z_index_stack,
834 Quad {
835 order: 0,
836 bounds: bounds.scale(scale_factor),
837 content_mask: content_mask.scale(scale_factor),
838 background: background.into(),
839 border_color: border_color.into(),
840 corner_radii: corner_radii.scale(scale_factor),
841 border_widths: border_widths.scale(scale_factor),
842 },
843 );
844 }
845
846 /// Paint the given `Path` into the scene for the current frame at the current z-index.
847 pub fn paint_path(&mut self, mut path: Path<Pixels>, color: impl Into<Hsla>) {
848 let scale_factor = self.scale_factor();
849 let content_mask = self.content_mask();
850 path.content_mask = content_mask;
851 path.color = color.into();
852 let window = &mut *self.window;
853 window.current_frame.scene_builder.insert(
854 &window.current_frame.z_index_stack,
855 path.scale(scale_factor),
856 );
857 }
858
859 /// Paint an underline into the scene for the current frame at the current z-index.
860 pub fn paint_underline(
861 &mut self,
862 origin: Point<Pixels>,
863 width: Pixels,
864 style: &UnderlineStyle,
865 ) -> Result<()> {
866 let scale_factor = self.scale_factor();
867 let height = if style.wavy {
868 style.thickness * 3.
869 } else {
870 style.thickness
871 };
872 let bounds = Bounds {
873 origin,
874 size: size(width, height),
875 };
876 let content_mask = self.content_mask();
877 let window = &mut *self.window;
878 window.current_frame.scene_builder.insert(
879 &window.current_frame.z_index_stack,
880 Underline {
881 order: 0,
882 bounds: bounds.scale(scale_factor),
883 content_mask: content_mask.scale(scale_factor),
884 thickness: style.thickness.scale(scale_factor),
885 color: style.color.unwrap_or_default(),
886 wavy: style.wavy,
887 },
888 );
889 Ok(())
890 }
891
892 /// Paint a monochrome (non-emoji) glyph into the scene for the current frame at the current z-index.
893 /// The y component of the origin is the baseline of the glyph.
894 pub fn paint_glyph(
895 &mut self,
896 origin: Point<Pixels>,
897 font_id: FontId,
898 glyph_id: GlyphId,
899 font_size: Pixels,
900 color: Hsla,
901 ) -> Result<()> {
902 let scale_factor = self.scale_factor();
903 let glyph_origin = origin.scale(scale_factor);
904 let subpixel_variant = Point {
905 x: (glyph_origin.x.0.fract() * SUBPIXEL_VARIANTS as f32).floor() as u8,
906 y: (glyph_origin.y.0.fract() * SUBPIXEL_VARIANTS as f32).floor() as u8,
907 };
908 let params = RenderGlyphParams {
909 font_id,
910 glyph_id,
911 font_size,
912 subpixel_variant,
913 scale_factor,
914 is_emoji: false,
915 };
916
917 let raster_bounds = self.text_system().raster_bounds(¶ms)?;
918 if !raster_bounds.is_zero() {
919 let tile =
920 self.window
921 .sprite_atlas
922 .get_or_insert_with(¶ms.clone().into(), &mut || {
923 let (size, bytes) = self.text_system().rasterize_glyph(¶ms)?;
924 Ok((size, Cow::Owned(bytes)))
925 })?;
926 let bounds = Bounds {
927 origin: glyph_origin.map(|px| px.floor()) + raster_bounds.origin.map(Into::into),
928 size: tile.bounds.size.map(Into::into),
929 };
930 let content_mask = self.content_mask().scale(scale_factor);
931 let window = &mut *self.window;
932 window.current_frame.scene_builder.insert(
933 &window.current_frame.z_index_stack,
934 MonochromeSprite {
935 order: 0,
936 bounds,
937 content_mask,
938 color,
939 tile,
940 },
941 );
942 }
943 Ok(())
944 }
945
946 /// Paint an emoji glyph into the scene for the current frame at the current z-index.
947 /// The y component of the origin is the baseline of the glyph.
948 pub fn paint_emoji(
949 &mut self,
950 origin: Point<Pixels>,
951 font_id: FontId,
952 glyph_id: GlyphId,
953 font_size: Pixels,
954 ) -> Result<()> {
955 let scale_factor = self.scale_factor();
956 let glyph_origin = origin.scale(scale_factor);
957 let params = RenderGlyphParams {
958 font_id,
959 glyph_id,
960 font_size,
961 // We don't render emojis with subpixel variants.
962 subpixel_variant: Default::default(),
963 scale_factor,
964 is_emoji: true,
965 };
966
967 let raster_bounds = self.text_system().raster_bounds(¶ms)?;
968 if !raster_bounds.is_zero() {
969 let tile =
970 self.window
971 .sprite_atlas
972 .get_or_insert_with(¶ms.clone().into(), &mut || {
973 let (size, bytes) = self.text_system().rasterize_glyph(¶ms)?;
974 Ok((size, Cow::Owned(bytes)))
975 })?;
976 let bounds = Bounds {
977 origin: glyph_origin.map(|px| px.floor()) + raster_bounds.origin.map(Into::into),
978 size: tile.bounds.size.map(Into::into),
979 };
980 let content_mask = self.content_mask().scale(scale_factor);
981 let window = &mut *self.window;
982
983 window.current_frame.scene_builder.insert(
984 &window.current_frame.z_index_stack,
985 PolychromeSprite {
986 order: 0,
987 bounds,
988 corner_radii: Default::default(),
989 content_mask,
990 tile,
991 grayscale: false,
992 },
993 );
994 }
995 Ok(())
996 }
997
998 /// Paint a monochrome SVG into the scene for the current frame at the current stacking context.
999 pub fn paint_svg(
1000 &mut self,
1001 bounds: Bounds<Pixels>,
1002 path: SharedString,
1003 color: Hsla,
1004 ) -> Result<()> {
1005 let scale_factor = self.scale_factor();
1006 let bounds = bounds.scale(scale_factor);
1007 // Render the SVG at twice the size to get a higher quality result.
1008 let params = RenderSvgParams {
1009 path,
1010 size: bounds
1011 .size
1012 .map(|pixels| DevicePixels::from((pixels.0 * 2.).ceil() as i32)),
1013 };
1014
1015 let tile =
1016 self.window
1017 .sprite_atlas
1018 .get_or_insert_with(¶ms.clone().into(), &mut || {
1019 let bytes = self.svg_renderer.render(¶ms)?;
1020 Ok((params.size, Cow::Owned(bytes)))
1021 })?;
1022 let content_mask = self.content_mask().scale(scale_factor);
1023
1024 let window = &mut *self.window;
1025 window.current_frame.scene_builder.insert(
1026 &window.current_frame.z_index_stack,
1027 MonochromeSprite {
1028 order: 0,
1029 bounds,
1030 content_mask,
1031 color,
1032 tile,
1033 },
1034 );
1035
1036 Ok(())
1037 }
1038
1039 /// Paint an image into the scene for the current frame at the current z-index.
1040 pub fn paint_image(
1041 &mut self,
1042 bounds: Bounds<Pixels>,
1043 corner_radii: Corners<Pixels>,
1044 data: Arc<ImageData>,
1045 grayscale: bool,
1046 ) -> Result<()> {
1047 let scale_factor = self.scale_factor();
1048 let bounds = bounds.scale(scale_factor);
1049 let params = RenderImageParams { image_id: data.id };
1050
1051 let tile = self
1052 .window
1053 .sprite_atlas
1054 .get_or_insert_with(¶ms.clone().into(), &mut || {
1055 Ok((data.size(), Cow::Borrowed(data.as_bytes())))
1056 })?;
1057 let content_mask = self.content_mask().scale(scale_factor);
1058 let corner_radii = corner_radii.scale(scale_factor);
1059
1060 let window = &mut *self.window;
1061 window.current_frame.scene_builder.insert(
1062 &window.current_frame.z_index_stack,
1063 PolychromeSprite {
1064 order: 0,
1065 bounds,
1066 content_mask,
1067 corner_radii,
1068 tile,
1069 grayscale,
1070 },
1071 );
1072 Ok(())
1073 }
1074
1075 /// Draw pixels to the display for this window based on the contents of its scene.
1076 pub(crate) fn draw(&mut self) {
1077 let root_view = self.window.root_view.take().unwrap();
1078
1079 self.start_frame();
1080
1081 self.with_z_index(0, |cx| {
1082 let available_space = cx.window.viewport_size.map(Into::into);
1083 root_view.draw(Point::zero(), available_space, cx);
1084 });
1085
1086 if let Some(active_drag) = self.app.active_drag.take() {
1087 self.with_z_index(1, |cx| {
1088 let offset = cx.mouse_position() - active_drag.cursor_offset;
1089 let available_space = size(AvailableSpace::MinContent, AvailableSpace::MinContent);
1090 active_drag.view.draw(offset, available_space, cx);
1091 cx.active_drag = Some(active_drag);
1092 });
1093 } else if let Some(active_tooltip) = self.app.active_tooltip.take() {
1094 self.with_z_index(1, |cx| {
1095 let available_space = size(AvailableSpace::MinContent, AvailableSpace::MinContent);
1096 active_tooltip
1097 .view
1098 .draw(active_tooltip.cursor_offset, available_space, cx);
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 fn focus_view<V: crate::FocusableView>(&mut self, view: &View<V>) -> Self::Result<()> {
1555 self.update_view(view, |view, cx| {
1556 view.focus_handle(cx).clone().focus(cx);
1557 })
1558 }
1559}
1560
1561impl<'a> std::ops::Deref for WindowContext<'a> {
1562 type Target = AppContext;
1563
1564 fn deref(&self) -> &Self::Target {
1565 &self.app
1566 }
1567}
1568
1569impl<'a> std::ops::DerefMut for WindowContext<'a> {
1570 fn deref_mut(&mut self) -> &mut Self::Target {
1571 &mut self.app
1572 }
1573}
1574
1575impl<'a> Borrow<AppContext> for WindowContext<'a> {
1576 fn borrow(&self) -> &AppContext {
1577 &self.app
1578 }
1579}
1580
1581impl<'a> BorrowMut<AppContext> for WindowContext<'a> {
1582 fn borrow_mut(&mut self) -> &mut AppContext {
1583 &mut self.app
1584 }
1585}
1586
1587pub trait BorrowWindow: BorrowMut<Window> + BorrowMut<AppContext> {
1588 fn app_mut(&mut self) -> &mut AppContext {
1589 self.borrow_mut()
1590 }
1591
1592 fn window(&self) -> &Window {
1593 self.borrow()
1594 }
1595
1596 fn window_mut(&mut self) -> &mut Window {
1597 self.borrow_mut()
1598 }
1599
1600 /// Pushes the given element id onto the global stack and invokes the given closure
1601 /// with a `GlobalElementId`, which disambiguates the given id in the context of its ancestor
1602 /// ids. Because elements are discarded and recreated on each frame, the `GlobalElementId` is
1603 /// used to associate state with identified elements across separate frames.
1604 fn with_element_id<R>(
1605 &mut self,
1606 id: Option<impl Into<ElementId>>,
1607 f: impl FnOnce(&mut Self) -> R,
1608 ) -> R {
1609 if let Some(id) = id.map(Into::into) {
1610 let window = self.window_mut();
1611 window.element_id_stack.push(id.into());
1612 let result = f(self);
1613 let window: &mut Window = self.borrow_mut();
1614 window.element_id_stack.pop();
1615 result
1616 } else {
1617 f(self)
1618 }
1619 }
1620
1621 /// Invoke the given function with the given content mask after intersecting it
1622 /// with the current mask.
1623 fn with_content_mask<R>(
1624 &mut self,
1625 mask: Option<ContentMask<Pixels>>,
1626 f: impl FnOnce(&mut Self) -> R,
1627 ) -> R {
1628 if let Some(mask) = mask {
1629 let mask = mask.intersect(&self.content_mask());
1630 self.window_mut()
1631 .current_frame
1632 .content_mask_stack
1633 .push(mask);
1634 let result = f(self);
1635 self.window_mut().current_frame.content_mask_stack.pop();
1636 result
1637 } else {
1638 f(self)
1639 }
1640 }
1641
1642 /// Update the global element offset relative to the current offset. This is used to implement
1643 /// scrolling.
1644 fn with_element_offset<R>(
1645 &mut self,
1646 offset: Point<Pixels>,
1647 f: impl FnOnce(&mut Self) -> R,
1648 ) -> R {
1649 if offset.is_zero() {
1650 return f(self);
1651 };
1652
1653 let abs_offset = self.element_offset() + offset;
1654 self.with_absolute_element_offset(abs_offset, f)
1655 }
1656
1657 /// Update the global element offset based on the given offset. This is used to implement
1658 /// drag handles and other manual painting of elements.
1659 fn with_absolute_element_offset<R>(
1660 &mut self,
1661 offset: Point<Pixels>,
1662 f: impl FnOnce(&mut Self) -> R,
1663 ) -> R {
1664 self.window_mut()
1665 .current_frame
1666 .element_offset_stack
1667 .push(offset);
1668 let result = f(self);
1669 self.window_mut().current_frame.element_offset_stack.pop();
1670 result
1671 }
1672
1673 /// Obtain the current element offset.
1674 fn element_offset(&self) -> Point<Pixels> {
1675 self.window()
1676 .current_frame
1677 .element_offset_stack
1678 .last()
1679 .copied()
1680 .unwrap_or_default()
1681 }
1682
1683 /// Update or intialize state for an element with the given id that lives across multiple
1684 /// frames. If an element with this id existed in the previous frame, its state will be passed
1685 /// to the given closure. The state returned by the closure will be stored so it can be referenced
1686 /// when drawing the next frame.
1687 fn with_element_state<S, R>(
1688 &mut self,
1689 id: ElementId,
1690 f: impl FnOnce(Option<S>, &mut Self) -> (R, S),
1691 ) -> R
1692 where
1693 S: 'static,
1694 {
1695 self.with_element_id(Some(id), |cx| {
1696 let global_id = cx.window().element_id_stack.clone();
1697
1698 if let Some(any) = cx
1699 .window_mut()
1700 .current_frame
1701 .element_states
1702 .remove(&global_id)
1703 .or_else(|| {
1704 cx.window_mut()
1705 .previous_frame
1706 .element_states
1707 .remove(&global_id)
1708 })
1709 {
1710 // Using the extra inner option to avoid needing to reallocate a new box.
1711 let mut state_box = any
1712 .downcast::<Option<S>>()
1713 .expect("invalid element state type for id");
1714 let state = state_box
1715 .take()
1716 .expect("element state is already on the stack");
1717 let (result, state) = f(Some(state), cx);
1718 state_box.replace(state);
1719 cx.window_mut()
1720 .current_frame
1721 .element_states
1722 .insert(global_id, state_box);
1723 result
1724 } else {
1725 let (result, state) = f(None, cx);
1726 cx.window_mut()
1727 .current_frame
1728 .element_states
1729 .insert(global_id, Box::new(Some(state)));
1730 result
1731 }
1732 })
1733 }
1734
1735 /// Like `with_element_state`, but for situations where the element_id is optional. If the
1736 /// id is `None`, no state will be retrieved or stored.
1737 fn with_optional_element_state<S, R>(
1738 &mut self,
1739 element_id: Option<ElementId>,
1740 f: impl FnOnce(Option<S>, &mut Self) -> (R, S),
1741 ) -> R
1742 where
1743 S: 'static,
1744 {
1745 if let Some(element_id) = element_id {
1746 self.with_element_state(element_id, f)
1747 } else {
1748 f(None, self).0
1749 }
1750 }
1751
1752 /// Obtain the current content mask.
1753 fn content_mask(&self) -> ContentMask<Pixels> {
1754 self.window()
1755 .current_frame
1756 .content_mask_stack
1757 .last()
1758 .cloned()
1759 .unwrap_or_else(|| ContentMask {
1760 bounds: Bounds {
1761 origin: Point::default(),
1762 size: self.window().viewport_size,
1763 },
1764 })
1765 }
1766
1767 /// The size of an em for the base font of the application. Adjusting this value allows the
1768 /// UI to scale, just like zooming a web page.
1769 fn rem_size(&self) -> Pixels {
1770 self.window().rem_size
1771 }
1772}
1773
1774impl Borrow<Window> for WindowContext<'_> {
1775 fn borrow(&self) -> &Window {
1776 &self.window
1777 }
1778}
1779
1780impl BorrowMut<Window> for WindowContext<'_> {
1781 fn borrow_mut(&mut self) -> &mut Window {
1782 &mut self.window
1783 }
1784}
1785
1786impl<T> BorrowWindow for T where T: BorrowMut<AppContext> + BorrowMut<Window> {}
1787
1788pub struct ViewContext<'a, V> {
1789 window_cx: WindowContext<'a>,
1790 view: &'a View<V>,
1791}
1792
1793impl<V> Borrow<AppContext> for ViewContext<'_, V> {
1794 fn borrow(&self) -> &AppContext {
1795 &*self.window_cx.app
1796 }
1797}
1798
1799impl<V> BorrowMut<AppContext> for ViewContext<'_, V> {
1800 fn borrow_mut(&mut self) -> &mut AppContext {
1801 &mut *self.window_cx.app
1802 }
1803}
1804
1805impl<V> Borrow<Window> for ViewContext<'_, V> {
1806 fn borrow(&self) -> &Window {
1807 &*self.window_cx.window
1808 }
1809}
1810
1811impl<V> BorrowMut<Window> for ViewContext<'_, V> {
1812 fn borrow_mut(&mut self) -> &mut Window {
1813 &mut *self.window_cx.window
1814 }
1815}
1816
1817impl<'a, V: 'static> ViewContext<'a, V> {
1818 pub(crate) fn new(app: &'a mut AppContext, window: &'a mut Window, view: &'a View<V>) -> Self {
1819 Self {
1820 window_cx: WindowContext::new(app, window),
1821 view,
1822 }
1823 }
1824
1825 pub fn entity_id(&self) -> EntityId {
1826 self.view.entity_id()
1827 }
1828
1829 pub fn view(&self) -> &View<V> {
1830 self.view
1831 }
1832
1833 pub fn model(&self) -> &Model<V> {
1834 &self.view.model
1835 }
1836
1837 /// Access the underlying window context.
1838 pub fn window_context(&mut self) -> &mut WindowContext<'a> {
1839 &mut self.window_cx
1840 }
1841
1842 pub fn with_z_index<R>(&mut self, z_index: u32, f: impl FnOnce(&mut Self) -> R) -> R {
1843 self.window.current_frame.z_index_stack.push(z_index);
1844 let result = f(self);
1845 self.window.current_frame.z_index_stack.pop();
1846 result
1847 }
1848
1849 pub fn on_next_frame(&mut self, f: impl FnOnce(&mut V, &mut ViewContext<V>) + 'static)
1850 where
1851 V: 'static,
1852 {
1853 let view = self.view().clone();
1854 self.window_cx.on_next_frame(move |cx| view.update(cx, f));
1855 }
1856
1857 /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
1858 /// that are currently on the stack to be returned to the app.
1859 pub fn defer(&mut self, f: impl FnOnce(&mut V, &mut ViewContext<V>) + 'static) {
1860 let view = self.view().downgrade();
1861 self.window_cx.defer(move |cx| {
1862 view.update(cx, f).ok();
1863 });
1864 }
1865
1866 pub fn observe<V2, E>(
1867 &mut self,
1868 entity: &E,
1869 mut on_notify: impl FnMut(&mut V, E, &mut ViewContext<'_, V>) + 'static,
1870 ) -> Subscription
1871 where
1872 V2: 'static,
1873 V: 'static,
1874 E: Entity<V2>,
1875 {
1876 let view = self.view().downgrade();
1877 let entity_id = entity.entity_id();
1878 let entity = entity.downgrade();
1879 let window_handle = self.window.handle;
1880 self.app.observers.insert(
1881 entity_id,
1882 Box::new(move |cx| {
1883 window_handle
1884 .update(cx, |_, cx| {
1885 if let Some(handle) = E::upgrade_from(&entity) {
1886 view.update(cx, |this, cx| on_notify(this, handle, cx))
1887 .is_ok()
1888 } else {
1889 false
1890 }
1891 })
1892 .unwrap_or(false)
1893 }),
1894 )
1895 }
1896
1897 pub fn subscribe<V2, E, Evt>(
1898 &mut self,
1899 entity: &E,
1900 mut on_event: impl FnMut(&mut V, E, &Evt, &mut ViewContext<'_, V>) + 'static,
1901 ) -> Subscription
1902 where
1903 V2: EventEmitter<Evt>,
1904 E: Entity<V2>,
1905 Evt: 'static,
1906 {
1907 let view = self.view().downgrade();
1908 let entity_id = entity.entity_id();
1909 let handle = entity.downgrade();
1910 let window_handle = self.window.handle;
1911 self.app.event_listeners.insert(
1912 entity_id,
1913 (
1914 TypeId::of::<Evt>(),
1915 Box::new(move |event, cx| {
1916 window_handle
1917 .update(cx, |_, cx| {
1918 if let Some(handle) = E::upgrade_from(&handle) {
1919 let event = event.downcast_ref().expect("invalid event type");
1920 view.update(cx, |this, cx| on_event(this, handle, event, cx))
1921 .is_ok()
1922 } else {
1923 false
1924 }
1925 })
1926 .unwrap_or(false)
1927 }),
1928 ),
1929 )
1930 }
1931
1932 pub fn on_release(
1933 &mut self,
1934 on_release: impl FnOnce(&mut V, &mut WindowContext) + 'static,
1935 ) -> Subscription {
1936 let window_handle = self.window.handle;
1937 self.app.release_listeners.insert(
1938 self.view.model.entity_id,
1939 Box::new(move |this, cx| {
1940 let this = this.downcast_mut().expect("invalid entity type");
1941 let _ = window_handle.update(cx, |_, cx| on_release(this, cx));
1942 }),
1943 )
1944 }
1945
1946 pub fn observe_release<V2, E>(
1947 &mut self,
1948 entity: &E,
1949 mut on_release: impl FnMut(&mut V, &mut V2, &mut ViewContext<'_, V>) + 'static,
1950 ) -> Subscription
1951 where
1952 V: 'static,
1953 V2: 'static,
1954 E: Entity<V2>,
1955 {
1956 let view = self.view().downgrade();
1957 let entity_id = entity.entity_id();
1958 let window_handle = self.window.handle;
1959 self.app.release_listeners.insert(
1960 entity_id,
1961 Box::new(move |entity, cx| {
1962 let entity = entity.downcast_mut().expect("invalid entity type");
1963 let _ = window_handle.update(cx, |_, cx| {
1964 view.update(cx, |this, cx| on_release(this, entity, cx))
1965 });
1966 }),
1967 )
1968 }
1969
1970 pub fn notify(&mut self) {
1971 self.window_cx.notify();
1972 self.window_cx.app.push_effect(Effect::Notify {
1973 emitter: self.view.model.entity_id,
1974 });
1975 }
1976
1977 pub fn observe_window_bounds(
1978 &mut self,
1979 mut callback: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
1980 ) -> Subscription {
1981 let view = self.view.downgrade();
1982 self.window.bounds_observers.insert(
1983 (),
1984 Box::new(move |cx| view.update(cx, |view, cx| callback(view, cx)).is_ok()),
1985 )
1986 }
1987
1988 pub fn observe_window_activation(
1989 &mut self,
1990 mut callback: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
1991 ) -> Subscription {
1992 let view = self.view.downgrade();
1993 self.window.activation_observers.insert(
1994 (),
1995 Box::new(move |cx| view.update(cx, |view, cx| callback(view, cx)).is_ok()),
1996 )
1997 }
1998
1999 /// Register a listener to be called when the given focus handle receives focus.
2000 /// Unlike [on_focus_changed], returns a subscription and persists until the subscription
2001 /// is dropped.
2002 pub fn on_focus(
2003 &mut self,
2004 handle: &FocusHandle,
2005 mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2006 ) -> Subscription {
2007 let view = self.view.downgrade();
2008 let focus_id = handle.id;
2009 self.window.focus_listeners.insert(
2010 (),
2011 Box::new(move |event, cx| {
2012 view.update(cx, |view, cx| {
2013 if event.focused.as_ref().map(|focused| focused.id) == Some(focus_id) {
2014 listener(view, cx)
2015 }
2016 })
2017 .is_ok()
2018 }),
2019 )
2020 }
2021
2022 /// Register a listener to be called when the given focus handle or one of its descendants receives focus.
2023 /// Unlike [on_focus_changed], returns a subscription and persists until the subscription
2024 /// is dropped.
2025 pub fn on_focus_in(
2026 &mut self,
2027 handle: &FocusHandle,
2028 mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2029 ) -> Subscription {
2030 let view = self.view.downgrade();
2031 let focus_id = handle.id;
2032 self.window.focus_listeners.insert(
2033 (),
2034 Box::new(move |event, cx| {
2035 view.update(cx, |view, cx| {
2036 if event
2037 .focused
2038 .as_ref()
2039 .map_or(false, |focused| focus_id.contains(focused.id, cx))
2040 {
2041 listener(view, cx)
2042 }
2043 })
2044 .is_ok()
2045 }),
2046 )
2047 }
2048
2049 /// Register a listener to be called when the given focus handle loses focus.
2050 /// Unlike [on_focus_changed], returns a subscription and persists until the subscription
2051 /// is dropped.
2052 pub fn on_blur(
2053 &mut self,
2054 handle: &FocusHandle,
2055 mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2056 ) -> Subscription {
2057 let view = self.view.downgrade();
2058 let focus_id = handle.id;
2059 self.window.focus_listeners.insert(
2060 (),
2061 Box::new(move |event, cx| {
2062 view.update(cx, |view, cx| {
2063 if event.blurred.as_ref().map(|blurred| blurred.id) == Some(focus_id) {
2064 listener(view, cx)
2065 }
2066 })
2067 .is_ok()
2068 }),
2069 )
2070 }
2071
2072 /// Register a listener to be called when the given focus handle or one of its descendants loses focus.
2073 /// Unlike [on_focus_changed], returns a subscription and persists until the subscription
2074 /// is dropped.
2075 pub fn on_focus_out(
2076 &mut self,
2077 handle: &FocusHandle,
2078 mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2079 ) -> Subscription {
2080 let view = self.view.downgrade();
2081 let focus_id = handle.id;
2082 self.window.focus_listeners.insert(
2083 (),
2084 Box::new(move |event, cx| {
2085 view.update(cx, |view, cx| {
2086 if event
2087 .blurred
2088 .as_ref()
2089 .map_or(false, |blurred| focus_id.contains(blurred.id, cx))
2090 {
2091 listener(view, cx)
2092 }
2093 })
2094 .is_ok()
2095 }),
2096 )
2097 }
2098
2099 /// Register a focus listener for the current frame only. It will be cleared
2100 /// on the next frame render. You should use this method only from within elements,
2101 /// and we may want to enforce that better via a different context type.
2102 // todo!() Move this to `FrameContext` to emphasize its individuality?
2103 pub fn on_focus_changed(
2104 &mut self,
2105 listener: impl Fn(&mut V, &FocusEvent, &mut ViewContext<V>) + 'static,
2106 ) {
2107 let handle = self.view().downgrade();
2108 self.window
2109 .current_frame
2110 .focus_listeners
2111 .push(Box::new(move |event, cx| {
2112 handle
2113 .update(cx, |view, cx| listener(view, event, cx))
2114 .log_err();
2115 }));
2116 }
2117
2118 pub fn with_key_dispatch<R>(
2119 &mut self,
2120 context: KeyContext,
2121 focus_handle: Option<FocusHandle>,
2122 f: impl FnOnce(Option<FocusHandle>, &mut Self) -> R,
2123 ) -> R {
2124 let window = &mut self.window;
2125 window
2126 .current_frame
2127 .dispatch_tree
2128 .push_node(context.clone());
2129 if let Some(focus_handle) = focus_handle.as_ref() {
2130 window
2131 .current_frame
2132 .dispatch_tree
2133 .make_focusable(focus_handle.id);
2134 }
2135 let result = f(focus_handle, self);
2136
2137 self.window.current_frame.dispatch_tree.pop_node();
2138
2139 result
2140 }
2141
2142 pub fn spawn<Fut, R>(
2143 &mut self,
2144 f: impl FnOnce(WeakView<V>, AsyncWindowContext) -> Fut,
2145 ) -> Task<R>
2146 where
2147 R: 'static,
2148 Fut: Future<Output = R> + 'static,
2149 {
2150 let view = self.view().downgrade();
2151 self.window_cx.spawn(|cx| f(view, cx))
2152 }
2153
2154 pub fn update_global<G, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R
2155 where
2156 G: 'static,
2157 {
2158 let mut global = self.app.lease_global::<G>();
2159 let result = f(&mut global, self);
2160 self.app.end_global_lease(global);
2161 result
2162 }
2163
2164 pub fn observe_global<G: 'static>(
2165 &mut self,
2166 mut f: impl FnMut(&mut V, &mut ViewContext<'_, V>) + 'static,
2167 ) -> Subscription {
2168 let window_handle = self.window.handle;
2169 let view = self.view().downgrade();
2170 self.global_observers.insert(
2171 TypeId::of::<G>(),
2172 Box::new(move |cx| {
2173 window_handle
2174 .update(cx, |_, cx| view.update(cx, |view, cx| f(view, cx)).is_ok())
2175 .unwrap_or(false)
2176 }),
2177 )
2178 }
2179
2180 pub fn on_mouse_event<Event: 'static>(
2181 &mut self,
2182 handler: impl Fn(&mut V, &Event, DispatchPhase, &mut ViewContext<V>) + 'static,
2183 ) {
2184 let handle = self.view().clone();
2185 self.window_cx.on_mouse_event(move |event, phase, cx| {
2186 handle.update(cx, |view, cx| {
2187 handler(view, event, phase, cx);
2188 })
2189 });
2190 }
2191
2192 pub fn on_key_event<Event: 'static>(
2193 &mut self,
2194 handler: impl Fn(&mut V, &Event, DispatchPhase, &mut ViewContext<V>) + 'static,
2195 ) {
2196 let handle = self.view().clone();
2197 self.window_cx.on_key_event(move |event, phase, cx| {
2198 handle.update(cx, |view, cx| {
2199 handler(view, event, phase, cx);
2200 })
2201 });
2202 }
2203
2204 pub fn on_action(
2205 &mut self,
2206 action_type: TypeId,
2207 handler: impl Fn(&mut V, &dyn Any, DispatchPhase, &mut ViewContext<V>) + 'static,
2208 ) {
2209 let handle = self.view().clone();
2210 self.window_cx
2211 .on_action(action_type, move |action, phase, cx| {
2212 handle.update(cx, |view, cx| {
2213 handler(view, action, phase, cx);
2214 })
2215 });
2216 }
2217
2218 /// Set an input handler, such as [ElementInputHandler], which interfaces with the
2219 /// platform to receive textual input with proper integration with concerns such
2220 /// as IME interactions.
2221 pub fn handle_input(
2222 &mut self,
2223 focus_handle: &FocusHandle,
2224 input_handler: impl PlatformInputHandler,
2225 ) {
2226 if focus_handle.is_focused(self) {
2227 self.window
2228 .platform_window
2229 .set_input_handler(Box::new(input_handler));
2230 }
2231 }
2232
2233 pub fn emit<Evt>(&mut self, event: Evt)
2234 where
2235 Evt: 'static,
2236 V: EventEmitter<Evt>,
2237 {
2238 let emitter = self.view.model.entity_id;
2239 self.app.push_effect(Effect::Emit {
2240 emitter,
2241 event_type: TypeId::of::<Evt>(),
2242 event: Box::new(event),
2243 });
2244 }
2245
2246 pub fn focus_self(&mut self)
2247 where
2248 V: FocusableView,
2249 {
2250 self.defer(|view, cx| view.focus_handle(cx).focus(cx))
2251 }
2252}
2253
2254impl<V> Context for ViewContext<'_, V> {
2255 type Result<U> = U;
2256
2257 fn build_model<T: 'static>(
2258 &mut self,
2259 build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
2260 ) -> Model<T> {
2261 self.window_cx.build_model(build_model)
2262 }
2263
2264 fn update_model<T: 'static, R>(
2265 &mut self,
2266 model: &Model<T>,
2267 update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
2268 ) -> R {
2269 self.window_cx.update_model(model, update)
2270 }
2271
2272 fn update_window<T, F>(&mut self, window: AnyWindowHandle, update: F) -> Result<T>
2273 where
2274 F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
2275 {
2276 self.window_cx.update_window(window, update)
2277 }
2278
2279 fn read_model<T, R>(
2280 &self,
2281 handle: &Model<T>,
2282 read: impl FnOnce(&T, &AppContext) -> R,
2283 ) -> Self::Result<R>
2284 where
2285 T: 'static,
2286 {
2287 self.window_cx.read_model(handle, read)
2288 }
2289
2290 fn read_window<T, R>(
2291 &self,
2292 window: &WindowHandle<T>,
2293 read: impl FnOnce(View<T>, &AppContext) -> R,
2294 ) -> Result<R>
2295 where
2296 T: 'static,
2297 {
2298 self.window_cx.read_window(window, read)
2299 }
2300}
2301
2302impl<V: 'static> VisualContext for ViewContext<'_, V> {
2303 fn build_view<W: Render + 'static>(
2304 &mut self,
2305 build_view_state: impl FnOnce(&mut ViewContext<'_, W>) -> W,
2306 ) -> Self::Result<View<W>> {
2307 self.window_cx.build_view(build_view_state)
2308 }
2309
2310 fn update_view<V2: 'static, R>(
2311 &mut self,
2312 view: &View<V2>,
2313 update: impl FnOnce(&mut V2, &mut ViewContext<'_, V2>) -> R,
2314 ) -> Self::Result<R> {
2315 self.window_cx.update_view(view, update)
2316 }
2317
2318 fn replace_root_view<W>(
2319 &mut self,
2320 build_view: impl FnOnce(&mut ViewContext<'_, W>) -> W,
2321 ) -> Self::Result<View<W>>
2322 where
2323 W: Render,
2324 {
2325 self.window_cx.replace_root_view(build_view)
2326 }
2327
2328 fn focus_view<W: FocusableView>(&mut self, view: &View<W>) -> Self::Result<()> {
2329 self.window_cx.focus_view(view)
2330 }
2331}
2332
2333impl<'a, V> std::ops::Deref for ViewContext<'a, V> {
2334 type Target = WindowContext<'a>;
2335
2336 fn deref(&self) -> &Self::Target {
2337 &self.window_cx
2338 }
2339}
2340
2341impl<'a, V> std::ops::DerefMut for ViewContext<'a, V> {
2342 fn deref_mut(&mut self) -> &mut Self::Target {
2343 &mut self.window_cx
2344 }
2345}
2346
2347// #[derive(Clone, Copy, Eq, PartialEq, Hash)]
2348slotmap::new_key_type! { pub struct WindowId; }
2349
2350impl WindowId {
2351 pub fn as_u64(&self) -> u64 {
2352 self.0.as_ffi()
2353 }
2354}
2355
2356#[derive(Deref, DerefMut)]
2357pub struct WindowHandle<V> {
2358 #[deref]
2359 #[deref_mut]
2360 pub(crate) any_handle: AnyWindowHandle,
2361 state_type: PhantomData<V>,
2362}
2363
2364impl<V: 'static + Render> WindowHandle<V> {
2365 pub fn new(id: WindowId) -> Self {
2366 WindowHandle {
2367 any_handle: AnyWindowHandle {
2368 id,
2369 state_type: TypeId::of::<V>(),
2370 },
2371 state_type: PhantomData,
2372 }
2373 }
2374
2375 pub fn update<C, R>(
2376 &self,
2377 cx: &mut C,
2378 update: impl FnOnce(&mut V, &mut ViewContext<'_, V>) -> R,
2379 ) -> Result<R>
2380 where
2381 C: Context,
2382 {
2383 cx.update_window(self.any_handle, |root_view, cx| {
2384 let view = root_view
2385 .downcast::<V>()
2386 .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
2387 Ok(cx.update_view(&view, update))
2388 })?
2389 }
2390
2391 pub fn read<'a>(&self, cx: &'a AppContext) -> Result<&'a V> {
2392 let x = cx
2393 .windows
2394 .get(self.id)
2395 .and_then(|window| {
2396 window
2397 .as_ref()
2398 .and_then(|window| window.root_view.clone())
2399 .map(|root_view| root_view.downcast::<V>())
2400 })
2401 .ok_or_else(|| anyhow!("window not found"))?
2402 .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
2403
2404 Ok(x.read(cx))
2405 }
2406
2407 pub fn read_with<C, R>(&self, cx: &C, read_with: impl FnOnce(&V, &AppContext) -> R) -> Result<R>
2408 where
2409 C: Context,
2410 {
2411 cx.read_window(self, |root_view, cx| read_with(root_view.read(cx), cx))
2412 }
2413
2414 pub fn root_view<C>(&self, cx: &C) -> Result<View<V>>
2415 where
2416 C: Context,
2417 {
2418 cx.read_window(self, |root_view, _cx| root_view.clone())
2419 }
2420
2421 pub fn is_active(&self, cx: &WindowContext) -> Option<bool> {
2422 cx.windows
2423 .get(self.id)
2424 .and_then(|window| window.as_ref().map(|window| window.active))
2425 }
2426}
2427
2428impl<V> Copy for WindowHandle<V> {}
2429
2430impl<V> Clone for WindowHandle<V> {
2431 fn clone(&self) -> Self {
2432 WindowHandle {
2433 any_handle: self.any_handle,
2434 state_type: PhantomData,
2435 }
2436 }
2437}
2438
2439impl<V> PartialEq for WindowHandle<V> {
2440 fn eq(&self, other: &Self) -> bool {
2441 self.any_handle == other.any_handle
2442 }
2443}
2444
2445impl<V> Eq for WindowHandle<V> {}
2446
2447impl<V> Hash for WindowHandle<V> {
2448 fn hash<H: Hasher>(&self, state: &mut H) {
2449 self.any_handle.hash(state);
2450 }
2451}
2452
2453impl<V: 'static> Into<AnyWindowHandle> for WindowHandle<V> {
2454 fn into(self) -> AnyWindowHandle {
2455 self.any_handle
2456 }
2457}
2458
2459#[derive(Copy, Clone, PartialEq, Eq, Hash)]
2460pub struct AnyWindowHandle {
2461 pub(crate) id: WindowId,
2462 state_type: TypeId,
2463}
2464
2465impl AnyWindowHandle {
2466 pub fn window_id(&self) -> WindowId {
2467 self.id
2468 }
2469
2470 pub fn downcast<T: 'static>(&self) -> Option<WindowHandle<T>> {
2471 if TypeId::of::<T>() == self.state_type {
2472 Some(WindowHandle {
2473 any_handle: *self,
2474 state_type: PhantomData,
2475 })
2476 } else {
2477 None
2478 }
2479 }
2480
2481 pub fn update<C, R>(
2482 self,
2483 cx: &mut C,
2484 update: impl FnOnce(AnyView, &mut WindowContext<'_>) -> R,
2485 ) -> Result<R>
2486 where
2487 C: Context,
2488 {
2489 cx.update_window(self, update)
2490 }
2491
2492 pub fn read<T, C, R>(self, cx: &C, read: impl FnOnce(View<T>, &AppContext) -> R) -> Result<R>
2493 where
2494 C: Context,
2495 T: 'static,
2496 {
2497 let view = self
2498 .downcast::<T>()
2499 .context("the type of the window's root view has changed")?;
2500
2501 cx.read_window(&view, read)
2502 }
2503}
2504
2505#[cfg(any(test, feature = "test-support"))]
2506impl From<SmallVec<[u32; 16]>> for StackingOrder {
2507 fn from(small_vec: SmallVec<[u32; 16]>) -> Self {
2508 StackingOrder(small_vec)
2509 }
2510}
2511
2512#[derive(Clone, Debug, Eq, PartialEq, Hash)]
2513pub enum ElementId {
2514 View(EntityId),
2515 Integer(usize),
2516 Name(SharedString),
2517 FocusHandle(FocusId),
2518}
2519
2520impl From<EntityId> for ElementId {
2521 fn from(id: EntityId) -> Self {
2522 ElementId::View(id)
2523 }
2524}
2525
2526impl From<usize> for ElementId {
2527 fn from(id: usize) -> Self {
2528 ElementId::Integer(id)
2529 }
2530}
2531
2532impl From<i32> for ElementId {
2533 fn from(id: i32) -> Self {
2534 Self::Integer(id as usize)
2535 }
2536}
2537
2538impl From<SharedString> for ElementId {
2539 fn from(name: SharedString) -> Self {
2540 ElementId::Name(name)
2541 }
2542}
2543
2544impl From<&'static str> for ElementId {
2545 fn from(name: &'static str) -> Self {
2546 ElementId::Name(name.into())
2547 }
2548}
2549
2550impl<'a> From<&'a FocusHandle> for ElementId {
2551 fn from(handle: &'a FocusHandle) -> Self {
2552 ElementId::FocusHandle(handle.id)
2553 }
2554}