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 #[must_use]
578 /// Add a node to the layout tree for the current frame. Takes the `Style` of the element for which
579 /// layout is being requested, along with the layout ids of any children. This method is called during
580 /// calls to the `Element::layout` trait method and enables any element to participate in layout.
581 pub fn request_layout(
582 &mut self,
583 style: &Style,
584 children: impl IntoIterator<Item = LayoutId>,
585 ) -> LayoutId {
586 self.app.layout_id_buffer.clear();
587 self.app.layout_id_buffer.extend(children.into_iter());
588 let rem_size = self.rem_size();
589
590 self.window
591 .layout_engine
592 .request_layout(style, rem_size, &self.app.layout_id_buffer)
593 }
594
595 /// Add a node to the layout tree for the current frame. Instead of taking a `Style` and children,
596 /// this variant takes a function that is invoked during layout so you can use arbitrary logic to
597 /// determine the element's size. One place this is used internally is when measuring text.
598 ///
599 /// The given closure is invoked at layout time with the known dimensions and available space and
600 /// returns a `Size`.
601 pub fn request_measured_layout<
602 F: Fn(Size<Option<Pixels>>, Size<AvailableSpace>) -> Size<Pixels> + Send + Sync + 'static,
603 >(
604 &mut self,
605 style: Style,
606 rem_size: Pixels,
607 measure: F,
608 ) -> LayoutId {
609 self.window
610 .layout_engine
611 .request_measured_layout(style, rem_size, measure)
612 }
613
614 pub fn compute_layout(&mut self, layout_id: LayoutId, available_space: Size<AvailableSpace>) {
615 self.window
616 .layout_engine
617 .compute_layout(layout_id, available_space)
618 }
619
620 /// Obtain the bounds computed for the given LayoutId relative to the window. This method should not
621 /// be invoked until the paint phase begins, and will usually be invoked by GPUI itself automatically
622 /// in order to pass your element its `Bounds` automatically.
623 pub fn layout_bounds(&mut self, layout_id: LayoutId) -> Bounds<Pixels> {
624 let mut bounds = self
625 .window
626 .layout_engine
627 .layout_bounds(layout_id)
628 .map(Into::into);
629 bounds.origin += self.element_offset();
630 bounds
631 }
632
633 fn window_bounds_changed(&mut self) {
634 self.window.scale_factor = self.window.platform_window.scale_factor();
635 self.window.viewport_size = self.window.platform_window.content_size();
636 self.window.bounds = self.window.platform_window.bounds();
637 self.window.display_id = self.window.platform_window.display().id();
638 self.window.dirty = true;
639
640 self.window
641 .bounds_observers
642 .clone()
643 .retain(&(), |callback| callback(self));
644 }
645
646 pub fn window_bounds(&self) -> WindowBounds {
647 self.window.bounds
648 }
649
650 pub fn viewport_size(&self) -> Size<Pixels> {
651 self.window.viewport_size
652 }
653
654 pub fn is_window_active(&self) -> bool {
655 self.window.active
656 }
657
658 pub fn zoom_window(&self) {
659 self.window.platform_window.zoom();
660 }
661
662 pub fn display(&self) -> Option<Rc<dyn PlatformDisplay>> {
663 self.platform
664 .displays()
665 .into_iter()
666 .find(|display| display.id() == self.window.display_id)
667 }
668
669 pub fn show_character_palette(&self) {
670 self.window.platform_window.show_character_palette();
671 }
672
673 /// The scale factor of the display associated with the window. For example, it could
674 /// return 2.0 for a "retina" display, indicating that each logical pixel should actually
675 /// be rendered as two pixels on screen.
676 pub fn scale_factor(&self) -> f32 {
677 self.window.scale_factor
678 }
679
680 /// The size of an em for the base font of the application. Adjusting this value allows the
681 /// UI to scale, just like zooming a web page.
682 pub fn rem_size(&self) -> Pixels {
683 self.window.rem_size
684 }
685
686 /// Sets the size of an em for the base font of the application. Adjusting this value allows the
687 /// UI to scale, just like zooming a web page.
688 pub fn set_rem_size(&mut self, rem_size: impl Into<Pixels>) {
689 self.window.rem_size = rem_size.into();
690 }
691
692 /// The line height associated with the current text style.
693 pub fn line_height(&self) -> Pixels {
694 let rem_size = self.rem_size();
695 let text_style = self.text_style();
696 text_style
697 .line_height
698 .to_pixels(text_style.font_size.into(), rem_size)
699 }
700
701 /// Call to prevent the default action of an event. Currently only used to prevent
702 /// parent elements from becoming focused on mouse down.
703 pub fn prevent_default(&mut self) {
704 self.window.default_prevented = true;
705 }
706
707 /// Obtain whether default has been prevented for the event currently being dispatched.
708 pub fn default_prevented(&self) -> bool {
709 self.window.default_prevented
710 }
711
712 /// Register a mouse event listener on the window for the current frame. The type of event
713 /// is determined by the first parameter of the given listener. When the next frame is rendered
714 /// the listener will be cleared.
715 ///
716 /// This is a fairly low-level method, so prefer using event handlers on elements unless you have
717 /// a specific need to register a global listener.
718 pub fn on_mouse_event<Event: 'static>(
719 &mut self,
720 handler: impl Fn(&Event, DispatchPhase, &mut WindowContext) + 'static,
721 ) {
722 let order = self.window.current_frame.z_index_stack.clone();
723 self.window
724 .current_frame
725 .mouse_listeners
726 .entry(TypeId::of::<Event>())
727 .or_default()
728 .push((
729 order,
730 Box::new(move |event: &dyn Any, phase, cx| {
731 handler(event.downcast_ref().unwrap(), phase, cx)
732 }),
733 ))
734 }
735
736 /// Register a key event listener on the window for the current frame. The type of event
737 /// is determined by the first parameter of the given listener. When the next frame is rendered
738 /// the listener will be cleared.
739 ///
740 /// This is a fairly low-level method, so prefer using event handlers on elements unless you have
741 /// a specific need to register a global listener.
742 pub fn on_key_event<Event: 'static>(
743 &mut self,
744 handler: impl Fn(&Event, DispatchPhase, &mut WindowContext) + 'static,
745 ) {
746 self.window
747 .current_frame
748 .dispatch_tree
749 .on_key_event(Rc::new(move |event, phase, cx| {
750 if let Some(event) = event.downcast_ref::<Event>() {
751 handler(event, phase, cx)
752 }
753 }));
754 }
755
756 /// Register an action listener on the window for the current frame. The type of action
757 /// is determined by the first parameter of the given listener. When the next frame is rendered
758 /// the listener will be cleared.
759 ///
760 /// This is a fairly low-level method, so prefer using action handlers on elements unless you have
761 /// a specific need to register a global listener.
762 pub fn on_action(
763 &mut self,
764 action_type: TypeId,
765 handler: impl Fn(&dyn Any, DispatchPhase, &mut WindowContext) + 'static,
766 ) {
767 self.window.current_frame.dispatch_tree.on_action(
768 action_type,
769 Rc::new(move |action, phase, cx| handler(action, phase, cx)),
770 );
771 }
772
773 /// The position of the mouse relative to the window.
774 pub fn mouse_position(&self) -> Point<Pixels> {
775 self.window.mouse_position
776 }
777
778 pub fn set_cursor_style(&mut self, style: CursorStyle) {
779 self.window.requested_cursor_style = Some(style)
780 }
781
782 /// Called during painting to invoke the given closure in a new stacking context. The given
783 /// z-index is interpreted relative to the previous call to `stack`.
784 pub fn with_z_index<R>(&mut self, z_index: u32, f: impl FnOnce(&mut Self) -> R) -> R {
785 self.window.current_frame.z_index_stack.push(z_index);
786 let result = f(self);
787 self.window.current_frame.z_index_stack.pop();
788 result
789 }
790
791 /// Paint one or more drop shadows into the scene for the current frame at the current z-index.
792 pub fn paint_shadows(
793 &mut self,
794 bounds: Bounds<Pixels>,
795 corner_radii: Corners<Pixels>,
796 shadows: &[BoxShadow],
797 ) {
798 let scale_factor = self.scale_factor();
799 let content_mask = self.content_mask();
800 let window = &mut *self.window;
801 for shadow in shadows {
802 let mut shadow_bounds = bounds;
803 shadow_bounds.origin += shadow.offset;
804 shadow_bounds.dilate(shadow.spread_radius);
805 window.current_frame.scene_builder.insert(
806 &window.current_frame.z_index_stack,
807 Shadow {
808 order: 0,
809 bounds: shadow_bounds.scale(scale_factor),
810 content_mask: content_mask.scale(scale_factor),
811 corner_radii: corner_radii.scale(scale_factor),
812 color: shadow.color,
813 blur_radius: shadow.blur_radius.scale(scale_factor),
814 },
815 );
816 }
817 }
818
819 /// Paint one or more quads into the scene for the current frame at the current stacking context.
820 /// Quads are colored rectangular regions with an optional background, border, and corner radius.
821 pub fn paint_quad(
822 &mut self,
823 bounds: Bounds<Pixels>,
824 corner_radii: Corners<Pixels>,
825 background: impl Into<Hsla>,
826 border_widths: Edges<Pixels>,
827 border_color: impl Into<Hsla>,
828 ) {
829 let scale_factor = self.scale_factor();
830 let content_mask = self.content_mask();
831
832 let window = &mut *self.window;
833 window.current_frame.scene_builder.insert(
834 &window.current_frame.z_index_stack,
835 Quad {
836 order: 0,
837 bounds: bounds.scale(scale_factor),
838 content_mask: content_mask.scale(scale_factor),
839 background: background.into(),
840 border_color: border_color.into(),
841 corner_radii: corner_radii.scale(scale_factor),
842 border_widths: border_widths.scale(scale_factor),
843 },
844 );
845 }
846
847 /// Paint the given `Path` into the scene for the current frame at the current z-index.
848 pub fn paint_path(&mut self, mut path: Path<Pixels>, color: impl Into<Hsla>) {
849 let scale_factor = self.scale_factor();
850 let content_mask = self.content_mask();
851 path.content_mask = content_mask;
852 path.color = color.into();
853 let window = &mut *self.window;
854 window.current_frame.scene_builder.insert(
855 &window.current_frame.z_index_stack,
856 path.scale(scale_factor),
857 );
858 }
859
860 /// Paint an underline into the scene for the current frame at the current z-index.
861 pub fn paint_underline(
862 &mut self,
863 origin: Point<Pixels>,
864 width: Pixels,
865 style: &UnderlineStyle,
866 ) -> Result<()> {
867 let scale_factor = self.scale_factor();
868 let height = if style.wavy {
869 style.thickness * 3.
870 } else {
871 style.thickness
872 };
873 let bounds = Bounds {
874 origin,
875 size: size(width, height),
876 };
877 let content_mask = self.content_mask();
878 let window = &mut *self.window;
879 window.current_frame.scene_builder.insert(
880 &window.current_frame.z_index_stack,
881 Underline {
882 order: 0,
883 bounds: bounds.scale(scale_factor),
884 content_mask: content_mask.scale(scale_factor),
885 thickness: style.thickness.scale(scale_factor),
886 color: style.color.unwrap_or_default(),
887 wavy: style.wavy,
888 },
889 );
890 Ok(())
891 }
892
893 /// Paint a monochrome (non-emoji) glyph into the scene for the current frame at the current z-index.
894 /// The y component of the origin is the baseline of the glyph.
895 pub fn paint_glyph(
896 &mut self,
897 origin: Point<Pixels>,
898 font_id: FontId,
899 glyph_id: GlyphId,
900 font_size: Pixels,
901 color: Hsla,
902 ) -> Result<()> {
903 let scale_factor = self.scale_factor();
904 let glyph_origin = origin.scale(scale_factor);
905 let subpixel_variant = Point {
906 x: (glyph_origin.x.0.fract() * SUBPIXEL_VARIANTS as f32).floor() as u8,
907 y: (glyph_origin.y.0.fract() * SUBPIXEL_VARIANTS as f32).floor() as u8,
908 };
909 let params = RenderGlyphParams {
910 font_id,
911 glyph_id,
912 font_size,
913 subpixel_variant,
914 scale_factor,
915 is_emoji: false,
916 };
917
918 let raster_bounds = self.text_system().raster_bounds(¶ms)?;
919 if !raster_bounds.is_zero() {
920 let tile =
921 self.window
922 .sprite_atlas
923 .get_or_insert_with(¶ms.clone().into(), &mut || {
924 let (size, bytes) = self.text_system().rasterize_glyph(¶ms)?;
925 Ok((size, Cow::Owned(bytes)))
926 })?;
927 let bounds = Bounds {
928 origin: glyph_origin.map(|px| px.floor()) + raster_bounds.origin.map(Into::into),
929 size: tile.bounds.size.map(Into::into),
930 };
931 let content_mask = self.content_mask().scale(scale_factor);
932 let window = &mut *self.window;
933 window.current_frame.scene_builder.insert(
934 &window.current_frame.z_index_stack,
935 MonochromeSprite {
936 order: 0,
937 bounds,
938 content_mask,
939 color,
940 tile,
941 },
942 );
943 }
944 Ok(())
945 }
946
947 /// Paint an emoji glyph into the scene for the current frame at the current z-index.
948 /// The y component of the origin is the baseline of the glyph.
949 pub fn paint_emoji(
950 &mut self,
951 origin: Point<Pixels>,
952 font_id: FontId,
953 glyph_id: GlyphId,
954 font_size: Pixels,
955 ) -> Result<()> {
956 let scale_factor = self.scale_factor();
957 let glyph_origin = origin.scale(scale_factor);
958 let params = RenderGlyphParams {
959 font_id,
960 glyph_id,
961 font_size,
962 // We don't render emojis with subpixel variants.
963 subpixel_variant: Default::default(),
964 scale_factor,
965 is_emoji: true,
966 };
967
968 let raster_bounds = self.text_system().raster_bounds(¶ms)?;
969 if !raster_bounds.is_zero() {
970 let tile =
971 self.window
972 .sprite_atlas
973 .get_or_insert_with(¶ms.clone().into(), &mut || {
974 let (size, bytes) = self.text_system().rasterize_glyph(¶ms)?;
975 Ok((size, Cow::Owned(bytes)))
976 })?;
977 let bounds = Bounds {
978 origin: glyph_origin.map(|px| px.floor()) + raster_bounds.origin.map(Into::into),
979 size: tile.bounds.size.map(Into::into),
980 };
981 let content_mask = self.content_mask().scale(scale_factor);
982 let window = &mut *self.window;
983
984 window.current_frame.scene_builder.insert(
985 &window.current_frame.z_index_stack,
986 PolychromeSprite {
987 order: 0,
988 bounds,
989 corner_radii: Default::default(),
990 content_mask,
991 tile,
992 grayscale: false,
993 },
994 );
995 }
996 Ok(())
997 }
998
999 /// Paint a monochrome SVG into the scene for the current frame at the current stacking context.
1000 pub fn paint_svg(
1001 &mut self,
1002 bounds: Bounds<Pixels>,
1003 path: SharedString,
1004 color: Hsla,
1005 ) -> Result<()> {
1006 let scale_factor = self.scale_factor();
1007 let bounds = bounds.scale(scale_factor);
1008 // Render the SVG at twice the size to get a higher quality result.
1009 let params = RenderSvgParams {
1010 path,
1011 size: bounds
1012 .size
1013 .map(|pixels| DevicePixels::from((pixels.0 * 2.).ceil() as i32)),
1014 };
1015
1016 let tile =
1017 self.window
1018 .sprite_atlas
1019 .get_or_insert_with(¶ms.clone().into(), &mut || {
1020 let bytes = self.svg_renderer.render(¶ms)?;
1021 Ok((params.size, Cow::Owned(bytes)))
1022 })?;
1023 let content_mask = self.content_mask().scale(scale_factor);
1024
1025 let window = &mut *self.window;
1026 window.current_frame.scene_builder.insert(
1027 &window.current_frame.z_index_stack,
1028 MonochromeSprite {
1029 order: 0,
1030 bounds,
1031 content_mask,
1032 color,
1033 tile,
1034 },
1035 );
1036
1037 Ok(())
1038 }
1039
1040 /// Paint an image into the scene for the current frame at the current z-index.
1041 pub fn paint_image(
1042 &mut self,
1043 bounds: Bounds<Pixels>,
1044 corner_radii: Corners<Pixels>,
1045 data: Arc<ImageData>,
1046 grayscale: bool,
1047 ) -> Result<()> {
1048 let scale_factor = self.scale_factor();
1049 let bounds = bounds.scale(scale_factor);
1050 let params = RenderImageParams { image_id: data.id };
1051
1052 let tile = self
1053 .window
1054 .sprite_atlas
1055 .get_or_insert_with(¶ms.clone().into(), &mut || {
1056 Ok((data.size(), Cow::Borrowed(data.as_bytes())))
1057 })?;
1058 let content_mask = self.content_mask().scale(scale_factor);
1059 let corner_radii = corner_radii.scale(scale_factor);
1060
1061 let window = &mut *self.window;
1062 window.current_frame.scene_builder.insert(
1063 &window.current_frame.z_index_stack,
1064 PolychromeSprite {
1065 order: 0,
1066 bounds,
1067 content_mask,
1068 corner_radii,
1069 tile,
1070 grayscale,
1071 },
1072 );
1073 Ok(())
1074 }
1075
1076 /// Draw pixels to the display for this window based on the contents of its scene.
1077 pub(crate) fn draw(&mut self) {
1078 let root_view = self.window.root_view.take().unwrap();
1079
1080 self.start_frame();
1081
1082 self.with_z_index(0, |cx| {
1083 let available_space = cx.window.viewport_size.map(Into::into);
1084 root_view.draw(Point::zero(), available_space, cx);
1085 });
1086
1087 if let Some(active_drag) = self.app.active_drag.take() {
1088 self.with_z_index(1, |cx| {
1089 let offset = cx.mouse_position() - active_drag.cursor_offset;
1090 let available_space = size(AvailableSpace::MinContent, AvailableSpace::MinContent);
1091 active_drag.view.draw(offset, available_space, cx);
1092 cx.active_drag = Some(active_drag);
1093 });
1094 } else if let Some(active_tooltip) = self.app.active_tooltip.take() {
1095 self.with_z_index(1, |cx| {
1096 let available_space = size(AvailableSpace::MinContent, AvailableSpace::MinContent);
1097 active_tooltip
1098 .view
1099 .draw(active_tooltip.cursor_offset, available_space, cx);
1100 });
1101 }
1102
1103 self.window
1104 .current_frame
1105 .dispatch_tree
1106 .preserve_keystroke_matchers(
1107 &mut self.window.previous_frame.dispatch_tree,
1108 self.window.focus,
1109 );
1110
1111 self.window.root_view = Some(root_view);
1112 let scene = self.window.current_frame.scene_builder.build();
1113
1114 self.window.platform_window.draw(scene);
1115 let cursor_style = self
1116 .window
1117 .requested_cursor_style
1118 .take()
1119 .unwrap_or(CursorStyle::Arrow);
1120 self.platform.set_cursor_style(cursor_style);
1121
1122 self.window.dirty = false;
1123 }
1124
1125 /// Rotate the current frame and the previous frame, then clear the current frame.
1126 /// We repopulate all state in the current frame during each paint.
1127 fn start_frame(&mut self) {
1128 self.text_system().start_frame();
1129
1130 let window = &mut *self.window;
1131 window.layout_engine.clear();
1132
1133 mem::swap(&mut window.previous_frame, &mut window.current_frame);
1134 let frame = &mut window.current_frame;
1135 frame.element_states.clear();
1136 frame.mouse_listeners.values_mut().for_each(Vec::clear);
1137 frame.focus_listeners.clear();
1138 frame.dispatch_tree.clear();
1139 }
1140
1141 /// Dispatch a mouse or keyboard event on the window.
1142 pub fn dispatch_event(&mut self, event: InputEvent) -> bool {
1143 // Handlers may set this to false by calling `stop_propagation`
1144 self.app.propagate_event = true;
1145 self.window.default_prevented = false;
1146
1147 let event = match event {
1148 // Track the mouse position with our own state, since accessing the platform
1149 // API for the mouse position can only occur on the main thread.
1150 InputEvent::MouseMove(mouse_move) => {
1151 self.window.mouse_position = mouse_move.position;
1152 InputEvent::MouseMove(mouse_move)
1153 }
1154 InputEvent::MouseDown(mouse_down) => {
1155 self.window.mouse_position = mouse_down.position;
1156 InputEvent::MouseDown(mouse_down)
1157 }
1158 InputEvent::MouseUp(mouse_up) => {
1159 self.window.mouse_position = mouse_up.position;
1160 InputEvent::MouseUp(mouse_up)
1161 }
1162 // Translate dragging and dropping of external files from the operating system
1163 // to internal drag and drop events.
1164 InputEvent::FileDrop(file_drop) => match file_drop {
1165 FileDropEvent::Entered { position, files } => {
1166 self.window.mouse_position = position;
1167 if self.active_drag.is_none() {
1168 self.active_drag = Some(AnyDrag {
1169 view: self.build_view(|_| files).into(),
1170 cursor_offset: position,
1171 });
1172 }
1173 InputEvent::MouseDown(MouseDownEvent {
1174 position,
1175 button: MouseButton::Left,
1176 click_count: 1,
1177 modifiers: Modifiers::default(),
1178 })
1179 }
1180 FileDropEvent::Pending { position } => {
1181 self.window.mouse_position = position;
1182 InputEvent::MouseMove(MouseMoveEvent {
1183 position,
1184 pressed_button: Some(MouseButton::Left),
1185 modifiers: Modifiers::default(),
1186 })
1187 }
1188 FileDropEvent::Submit { position } => {
1189 self.window.mouse_position = position;
1190 InputEvent::MouseUp(MouseUpEvent {
1191 button: MouseButton::Left,
1192 position,
1193 modifiers: Modifiers::default(),
1194 click_count: 1,
1195 })
1196 }
1197 FileDropEvent::Exited => InputEvent::MouseUp(MouseUpEvent {
1198 button: MouseButton::Left,
1199 position: Point::default(),
1200 modifiers: Modifiers::default(),
1201 click_count: 1,
1202 }),
1203 },
1204 _ => event,
1205 };
1206
1207 if let Some(any_mouse_event) = event.mouse_event() {
1208 self.dispatch_mouse_event(any_mouse_event);
1209 } else if let Some(any_key_event) = event.keyboard_event() {
1210 self.dispatch_key_event(any_key_event);
1211 }
1212
1213 !self.app.propagate_event
1214 }
1215
1216 fn dispatch_mouse_event(&mut self, event: &dyn Any) {
1217 if let Some(mut handlers) = self
1218 .window
1219 .current_frame
1220 .mouse_listeners
1221 .remove(&event.type_id())
1222 {
1223 // Because handlers may add other handlers, we sort every time.
1224 handlers.sort_by(|(a, _), (b, _)| a.cmp(b));
1225
1226 // Capture phase, events bubble from back to front. Handlers for this phase are used for
1227 // special purposes, such as detecting events outside of a given Bounds.
1228 for (_, handler) in &mut handlers {
1229 handler(event, DispatchPhase::Capture, self);
1230 if !self.app.propagate_event {
1231 break;
1232 }
1233 }
1234
1235 // Bubble phase, where most normal handlers do their work.
1236 if self.app.propagate_event {
1237 for (_, handler) in handlers.iter_mut().rev() {
1238 handler(event, DispatchPhase::Bubble, self);
1239 if !self.app.propagate_event {
1240 break;
1241 }
1242 }
1243 }
1244
1245 if self.app.propagate_event && event.downcast_ref::<MouseUpEvent>().is_some() {
1246 self.active_drag = None;
1247 }
1248
1249 // Just in case any handlers added new handlers, which is weird, but possible.
1250 handlers.extend(
1251 self.window
1252 .current_frame
1253 .mouse_listeners
1254 .get_mut(&event.type_id())
1255 .into_iter()
1256 .flat_map(|handlers| handlers.drain(..)),
1257 );
1258 self.window
1259 .current_frame
1260 .mouse_listeners
1261 .insert(event.type_id(), handlers);
1262 }
1263 }
1264
1265 fn dispatch_key_event(&mut self, event: &dyn Any) {
1266 if let Some(node_id) = self.window.focus.and_then(|focus_id| {
1267 self.window
1268 .current_frame
1269 .dispatch_tree
1270 .focusable_node_id(focus_id)
1271 }) {
1272 let dispatch_path = self
1273 .window
1274 .current_frame
1275 .dispatch_tree
1276 .dispatch_path(node_id);
1277
1278 // Capture phase
1279 let mut context_stack: SmallVec<[KeyContext; 16]> = SmallVec::new();
1280 self.propagate_event = true;
1281
1282 for node_id in &dispatch_path {
1283 let node = self.window.current_frame.dispatch_tree.node(*node_id);
1284
1285 if !node.context.is_empty() {
1286 context_stack.push(node.context.clone());
1287 }
1288
1289 for key_listener in node.key_listeners.clone() {
1290 key_listener(event, DispatchPhase::Capture, self);
1291 if !self.propagate_event {
1292 return;
1293 }
1294 }
1295 }
1296
1297 // Bubble phase
1298 for node_id in dispatch_path.iter().rev() {
1299 // Handle low level key events
1300 let node = self.window.current_frame.dispatch_tree.node(*node_id);
1301 for key_listener in node.key_listeners.clone() {
1302 key_listener(event, DispatchPhase::Bubble, self);
1303 if !self.propagate_event {
1304 return;
1305 }
1306 }
1307
1308 // Match keystrokes
1309 let node = self.window.current_frame.dispatch_tree.node(*node_id);
1310 if !node.context.is_empty() {
1311 if let Some(key_down_event) = event.downcast_ref::<KeyDownEvent>() {
1312 if let Some(action) = self
1313 .window
1314 .current_frame
1315 .dispatch_tree
1316 .dispatch_key(&key_down_event.keystroke, &context_stack)
1317 {
1318 self.dispatch_action_on_node(*node_id, action);
1319 if !self.propagate_event {
1320 return;
1321 }
1322 }
1323 }
1324
1325 context_stack.pop();
1326 }
1327 }
1328 }
1329 }
1330
1331 fn dispatch_action_on_node(&mut self, node_id: DispatchNodeId, action: Box<dyn Action>) {
1332 let dispatch_path = self
1333 .window
1334 .current_frame
1335 .dispatch_tree
1336 .dispatch_path(node_id);
1337
1338 // Capture phase
1339 for node_id in &dispatch_path {
1340 let node = self.window.current_frame.dispatch_tree.node(*node_id);
1341 for DispatchActionListener {
1342 action_type,
1343 listener,
1344 } in node.action_listeners.clone()
1345 {
1346 let any_action = action.as_any();
1347 if action_type == any_action.type_id() {
1348 listener(any_action, DispatchPhase::Capture, self);
1349 if !self.propagate_event {
1350 return;
1351 }
1352 }
1353 }
1354 }
1355
1356 // Bubble phase
1357 for node_id in dispatch_path.iter().rev() {
1358 let node = self.window.current_frame.dispatch_tree.node(*node_id);
1359 for DispatchActionListener {
1360 action_type,
1361 listener,
1362 } in node.action_listeners.clone()
1363 {
1364 let any_action = action.as_any();
1365 if action_type == any_action.type_id() {
1366 self.propagate_event = false; // Actions stop propagation by default during the bubble phase
1367 listener(any_action, DispatchPhase::Bubble, self);
1368 if !self.propagate_event {
1369 return;
1370 }
1371 }
1372 }
1373 }
1374 }
1375
1376 /// Register the given handler to be invoked whenever the global of the given type
1377 /// is updated.
1378 pub fn observe_global<G: 'static>(
1379 &mut self,
1380 f: impl Fn(&mut WindowContext<'_>) + 'static,
1381 ) -> Subscription {
1382 let window_handle = self.window.handle;
1383 self.global_observers.insert(
1384 TypeId::of::<G>(),
1385 Box::new(move |cx| window_handle.update(cx, |_, cx| f(cx)).is_ok()),
1386 )
1387 }
1388
1389 pub fn activate_window(&self) {
1390 self.window.platform_window.activate();
1391 }
1392
1393 pub fn minimize_window(&self) {
1394 self.window.platform_window.minimize();
1395 }
1396
1397 pub fn toggle_full_screen(&self) {
1398 self.window.platform_window.toggle_full_screen();
1399 }
1400
1401 pub fn prompt(
1402 &self,
1403 level: PromptLevel,
1404 msg: &str,
1405 answers: &[&str],
1406 ) -> oneshot::Receiver<usize> {
1407 self.window.platform_window.prompt(level, msg, answers)
1408 }
1409
1410 pub fn available_actions(&self) -> Vec<Box<dyn Action>> {
1411 if let Some(focus_id) = self.window.focus {
1412 self.window
1413 .current_frame
1414 .dispatch_tree
1415 .available_actions(focus_id)
1416 } else {
1417 Vec::new()
1418 }
1419 }
1420
1421 pub fn bindings_for_action(&self, action: &dyn Action) -> Vec<KeyBinding> {
1422 self.window
1423 .current_frame
1424 .dispatch_tree
1425 .bindings_for_action(action)
1426 }
1427}
1428
1429impl Context for WindowContext<'_> {
1430 type Result<T> = T;
1431
1432 fn build_model<T>(
1433 &mut self,
1434 build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
1435 ) -> Model<T>
1436 where
1437 T: 'static,
1438 {
1439 let slot = self.app.entities.reserve();
1440 let model = build_model(&mut ModelContext::new(&mut *self.app, slot.downgrade()));
1441 self.entities.insert(slot, model)
1442 }
1443
1444 fn update_model<T: 'static, R>(
1445 &mut self,
1446 model: &Model<T>,
1447 update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
1448 ) -> R {
1449 let mut entity = self.entities.lease(model);
1450 let result = update(
1451 &mut *entity,
1452 &mut ModelContext::new(&mut *self.app, model.downgrade()),
1453 );
1454 self.entities.end_lease(entity);
1455 result
1456 }
1457
1458 fn update_window<T, F>(&mut self, window: AnyWindowHandle, update: F) -> Result<T>
1459 where
1460 F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
1461 {
1462 if window == self.window.handle {
1463 let root_view = self.window.root_view.clone().unwrap();
1464 Ok(update(root_view, self))
1465 } else {
1466 window.update(self.app, update)
1467 }
1468 }
1469
1470 fn read_model<T, R>(
1471 &self,
1472 handle: &Model<T>,
1473 read: impl FnOnce(&T, &AppContext) -> R,
1474 ) -> Self::Result<R>
1475 where
1476 T: 'static,
1477 {
1478 let entity = self.entities.read(handle);
1479 read(&*entity, &*self.app)
1480 }
1481
1482 fn read_window<T, R>(
1483 &self,
1484 window: &WindowHandle<T>,
1485 read: impl FnOnce(View<T>, &AppContext) -> R,
1486 ) -> Result<R>
1487 where
1488 T: 'static,
1489 {
1490 if window.any_handle == self.window.handle {
1491 let root_view = self
1492 .window
1493 .root_view
1494 .clone()
1495 .unwrap()
1496 .downcast::<T>()
1497 .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
1498 Ok(read(root_view, self))
1499 } else {
1500 self.app.read_window(window, read)
1501 }
1502 }
1503}
1504
1505impl VisualContext for WindowContext<'_> {
1506 fn build_view<V>(
1507 &mut self,
1508 build_view_state: impl FnOnce(&mut ViewContext<'_, V>) -> V,
1509 ) -> Self::Result<View<V>>
1510 where
1511 V: 'static + Render,
1512 {
1513 let slot = self.app.entities.reserve();
1514 let view = View {
1515 model: slot.clone(),
1516 };
1517 let mut cx = ViewContext::new(&mut *self.app, &mut *self.window, &view);
1518 let entity = build_view_state(&mut cx);
1519 cx.entities.insert(slot, entity);
1520
1521 cx.new_view_observers
1522 .clone()
1523 .retain(&TypeId::of::<V>(), |observer| {
1524 let any_view = AnyView::from(view.clone());
1525 (observer)(any_view, self);
1526 true
1527 });
1528
1529 view
1530 }
1531
1532 /// Update the given view. Prefer calling `View::update` instead, which calls this method.
1533 fn update_view<T: 'static, R>(
1534 &mut self,
1535 view: &View<T>,
1536 update: impl FnOnce(&mut T, &mut ViewContext<'_, T>) -> R,
1537 ) -> Self::Result<R> {
1538 let mut lease = self.app.entities.lease(&view.model);
1539 let mut cx = ViewContext::new(&mut *self.app, &mut *self.window, &view);
1540 let result = update(&mut *lease, &mut cx);
1541 cx.app.entities.end_lease(lease);
1542 result
1543 }
1544
1545 fn replace_root_view<V>(
1546 &mut self,
1547 build_view: impl FnOnce(&mut ViewContext<'_, V>) -> V,
1548 ) -> Self::Result<View<V>>
1549 where
1550 V: Render,
1551 {
1552 let slot = self.app.entities.reserve();
1553 let view = View {
1554 model: slot.clone(),
1555 };
1556 let mut cx = ViewContext::new(&mut *self.app, &mut *self.window, &view);
1557 let entity = build_view(&mut cx);
1558 self.entities.insert(slot, entity);
1559 self.window.root_view = Some(view.clone().into());
1560 view
1561 }
1562
1563 fn focus_view<V: crate::FocusableView>(&mut self, view: &View<V>) -> Self::Result<()> {
1564 self.update_view(view, |view, cx| {
1565 view.focus_handle(cx).clone().focus(cx);
1566 })
1567 }
1568}
1569
1570impl<'a> std::ops::Deref for WindowContext<'a> {
1571 type Target = AppContext;
1572
1573 fn deref(&self) -> &Self::Target {
1574 &self.app
1575 }
1576}
1577
1578impl<'a> std::ops::DerefMut for WindowContext<'a> {
1579 fn deref_mut(&mut self) -> &mut Self::Target {
1580 &mut self.app
1581 }
1582}
1583
1584impl<'a> Borrow<AppContext> for WindowContext<'a> {
1585 fn borrow(&self) -> &AppContext {
1586 &self.app
1587 }
1588}
1589
1590impl<'a> BorrowMut<AppContext> for WindowContext<'a> {
1591 fn borrow_mut(&mut self) -> &mut AppContext {
1592 &mut self.app
1593 }
1594}
1595
1596pub trait BorrowWindow: BorrowMut<Window> + BorrowMut<AppContext> {
1597 fn app_mut(&mut self) -> &mut AppContext {
1598 self.borrow_mut()
1599 }
1600
1601 fn window(&self) -> &Window {
1602 self.borrow()
1603 }
1604
1605 fn window_mut(&mut self) -> &mut Window {
1606 self.borrow_mut()
1607 }
1608
1609 /// Pushes the given element id onto the global stack and invokes the given closure
1610 /// with a `GlobalElementId`, which disambiguates the given id in the context of its ancestor
1611 /// ids. Because elements are discarded and recreated on each frame, the `GlobalElementId` is
1612 /// used to associate state with identified elements across separate frames.
1613 fn with_element_id<R>(
1614 &mut self,
1615 id: Option<impl Into<ElementId>>,
1616 f: impl FnOnce(&mut Self) -> R,
1617 ) -> R {
1618 if let Some(id) = id.map(Into::into) {
1619 let window = self.window_mut();
1620 window.element_id_stack.push(id.into());
1621 let result = f(self);
1622 let window: &mut Window = self.borrow_mut();
1623 window.element_id_stack.pop();
1624 result
1625 } else {
1626 f(self)
1627 }
1628 }
1629
1630 /// Invoke the given function with the given content mask after intersecting it
1631 /// with the current mask.
1632 fn with_content_mask<R>(
1633 &mut self,
1634 mask: Option<ContentMask<Pixels>>,
1635 f: impl FnOnce(&mut Self) -> R,
1636 ) -> R {
1637 if let Some(mask) = mask {
1638 let mask = mask.intersect(&self.content_mask());
1639 self.window_mut()
1640 .current_frame
1641 .content_mask_stack
1642 .push(mask);
1643 let result = f(self);
1644 self.window_mut().current_frame.content_mask_stack.pop();
1645 result
1646 } else {
1647 f(self)
1648 }
1649 }
1650
1651 /// Update the global element offset relative to the current offset. This is used to implement
1652 /// scrolling.
1653 fn with_element_offset<R>(
1654 &mut self,
1655 offset: Point<Pixels>,
1656 f: impl FnOnce(&mut Self) -> R,
1657 ) -> R {
1658 if offset.is_zero() {
1659 return f(self);
1660 };
1661
1662 let abs_offset = self.element_offset() + offset;
1663 self.with_absolute_element_offset(abs_offset, f)
1664 }
1665
1666 /// Update the global element offset based on the given offset. This is used to implement
1667 /// drag handles and other manual painting of elements.
1668 fn with_absolute_element_offset<R>(
1669 &mut self,
1670 offset: Point<Pixels>,
1671 f: impl FnOnce(&mut Self) -> R,
1672 ) -> R {
1673 self.window_mut()
1674 .current_frame
1675 .element_offset_stack
1676 .push(offset);
1677 let result = f(self);
1678 self.window_mut().current_frame.element_offset_stack.pop();
1679 result
1680 }
1681
1682 /// Obtain the current element offset.
1683 fn element_offset(&self) -> Point<Pixels> {
1684 self.window()
1685 .current_frame
1686 .element_offset_stack
1687 .last()
1688 .copied()
1689 .unwrap_or_default()
1690 }
1691
1692 /// Update or intialize state for an element with the given id that lives across multiple
1693 /// frames. If an element with this id existed in the previous frame, its state will be passed
1694 /// to the given closure. The state returned by the closure will be stored so it can be referenced
1695 /// when drawing the next frame.
1696 fn with_element_state<S, R>(
1697 &mut self,
1698 id: ElementId,
1699 f: impl FnOnce(Option<S>, &mut Self) -> (R, S),
1700 ) -> R
1701 where
1702 S: 'static,
1703 {
1704 self.with_element_id(Some(id), |cx| {
1705 let global_id = cx.window().element_id_stack.clone();
1706
1707 if let Some(any) = cx
1708 .window_mut()
1709 .current_frame
1710 .element_states
1711 .remove(&global_id)
1712 .or_else(|| {
1713 cx.window_mut()
1714 .previous_frame
1715 .element_states
1716 .remove(&global_id)
1717 })
1718 {
1719 // Using the extra inner option to avoid needing to reallocate a new box.
1720 let mut state_box = any
1721 .downcast::<Option<S>>()
1722 .expect("invalid element state type for id");
1723 let state = state_box
1724 .take()
1725 .expect("element state is already on the stack");
1726 let (result, state) = f(Some(state), cx);
1727 state_box.replace(state);
1728 cx.window_mut()
1729 .current_frame
1730 .element_states
1731 .insert(global_id, state_box);
1732 result
1733 } else {
1734 let (result, state) = f(None, cx);
1735 cx.window_mut()
1736 .current_frame
1737 .element_states
1738 .insert(global_id, Box::new(Some(state)));
1739 result
1740 }
1741 })
1742 }
1743
1744 /// Like `with_element_state`, but for situations where the element_id is optional. If the
1745 /// id is `None`, no state will be retrieved or stored.
1746 fn with_optional_element_state<S, R>(
1747 &mut self,
1748 element_id: Option<ElementId>,
1749 f: impl FnOnce(Option<S>, &mut Self) -> (R, S),
1750 ) -> R
1751 where
1752 S: 'static,
1753 {
1754 if let Some(element_id) = element_id {
1755 self.with_element_state(element_id, f)
1756 } else {
1757 f(None, self).0
1758 }
1759 }
1760
1761 /// Obtain the current content mask.
1762 fn content_mask(&self) -> ContentMask<Pixels> {
1763 self.window()
1764 .current_frame
1765 .content_mask_stack
1766 .last()
1767 .cloned()
1768 .unwrap_or_else(|| ContentMask {
1769 bounds: Bounds {
1770 origin: Point::default(),
1771 size: self.window().viewport_size,
1772 },
1773 })
1774 }
1775
1776 /// The size of an em for the base font of the application. Adjusting this value allows the
1777 /// UI to scale, just like zooming a web page.
1778 fn rem_size(&self) -> Pixels {
1779 self.window().rem_size
1780 }
1781}
1782
1783impl Borrow<Window> for WindowContext<'_> {
1784 fn borrow(&self) -> &Window {
1785 &self.window
1786 }
1787}
1788
1789impl BorrowMut<Window> for WindowContext<'_> {
1790 fn borrow_mut(&mut self) -> &mut Window {
1791 &mut self.window
1792 }
1793}
1794
1795impl<T> BorrowWindow for T where T: BorrowMut<AppContext> + BorrowMut<Window> {}
1796
1797pub struct ViewContext<'a, V> {
1798 window_cx: WindowContext<'a>,
1799 view: &'a View<V>,
1800}
1801
1802impl<V> Borrow<AppContext> for ViewContext<'_, V> {
1803 fn borrow(&self) -> &AppContext {
1804 &*self.window_cx.app
1805 }
1806}
1807
1808impl<V> BorrowMut<AppContext> for ViewContext<'_, V> {
1809 fn borrow_mut(&mut self) -> &mut AppContext {
1810 &mut *self.window_cx.app
1811 }
1812}
1813
1814impl<V> Borrow<Window> for ViewContext<'_, V> {
1815 fn borrow(&self) -> &Window {
1816 &*self.window_cx.window
1817 }
1818}
1819
1820impl<V> BorrowMut<Window> for ViewContext<'_, V> {
1821 fn borrow_mut(&mut self) -> &mut Window {
1822 &mut *self.window_cx.window
1823 }
1824}
1825
1826impl<'a, V: 'static> ViewContext<'a, V> {
1827 pub(crate) fn new(app: &'a mut AppContext, window: &'a mut Window, view: &'a View<V>) -> Self {
1828 Self {
1829 window_cx: WindowContext::new(app, window),
1830 view,
1831 }
1832 }
1833
1834 pub fn entity_id(&self) -> EntityId {
1835 self.view.entity_id()
1836 }
1837
1838 pub fn view(&self) -> &View<V> {
1839 self.view
1840 }
1841
1842 pub fn model(&self) -> &Model<V> {
1843 &self.view.model
1844 }
1845
1846 /// Access the underlying window context.
1847 pub fn window_context(&mut self) -> &mut WindowContext<'a> {
1848 &mut self.window_cx
1849 }
1850
1851 pub fn with_z_index<R>(&mut self, z_index: u32, f: impl FnOnce(&mut Self) -> R) -> R {
1852 self.window.current_frame.z_index_stack.push(z_index);
1853 let result = f(self);
1854 self.window.current_frame.z_index_stack.pop();
1855 result
1856 }
1857
1858 pub fn on_next_frame(&mut self, f: impl FnOnce(&mut V, &mut ViewContext<V>) + 'static)
1859 where
1860 V: 'static,
1861 {
1862 let view = self.view().clone();
1863 self.window_cx.on_next_frame(move |cx| view.update(cx, f));
1864 }
1865
1866 /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
1867 /// that are currently on the stack to be returned to the app.
1868 pub fn defer(&mut self, f: impl FnOnce(&mut V, &mut ViewContext<V>) + 'static) {
1869 let view = self.view().downgrade();
1870 self.window_cx.defer(move |cx| {
1871 view.update(cx, f).ok();
1872 });
1873 }
1874
1875 pub fn observe<V2, E>(
1876 &mut self,
1877 entity: &E,
1878 mut on_notify: impl FnMut(&mut V, E, &mut ViewContext<'_, V>) + 'static,
1879 ) -> Subscription
1880 where
1881 V2: 'static,
1882 V: 'static,
1883 E: Entity<V2>,
1884 {
1885 let view = self.view().downgrade();
1886 let entity_id = entity.entity_id();
1887 let entity = entity.downgrade();
1888 let window_handle = self.window.handle;
1889 self.app.observers.insert(
1890 entity_id,
1891 Box::new(move |cx| {
1892 window_handle
1893 .update(cx, |_, cx| {
1894 if let Some(handle) = E::upgrade_from(&entity) {
1895 view.update(cx, |this, cx| on_notify(this, handle, cx))
1896 .is_ok()
1897 } else {
1898 false
1899 }
1900 })
1901 .unwrap_or(false)
1902 }),
1903 )
1904 }
1905
1906 pub fn subscribe<V2, E, Evt>(
1907 &mut self,
1908 entity: &E,
1909 mut on_event: impl FnMut(&mut V, E, &Evt, &mut ViewContext<'_, V>) + 'static,
1910 ) -> Subscription
1911 where
1912 V2: EventEmitter<Evt>,
1913 E: Entity<V2>,
1914 Evt: 'static,
1915 {
1916 let view = self.view().downgrade();
1917 let entity_id = entity.entity_id();
1918 let handle = entity.downgrade();
1919 let window_handle = self.window.handle;
1920 self.app.event_listeners.insert(
1921 entity_id,
1922 (
1923 TypeId::of::<Evt>(),
1924 Box::new(move |event, cx| {
1925 window_handle
1926 .update(cx, |_, cx| {
1927 if let Some(handle) = E::upgrade_from(&handle) {
1928 let event = event.downcast_ref().expect("invalid event type");
1929 view.update(cx, |this, cx| on_event(this, handle, event, cx))
1930 .is_ok()
1931 } else {
1932 false
1933 }
1934 })
1935 .unwrap_or(false)
1936 }),
1937 ),
1938 )
1939 }
1940
1941 pub fn on_release(
1942 &mut self,
1943 on_release: impl FnOnce(&mut V, &mut WindowContext) + 'static,
1944 ) -> Subscription {
1945 let window_handle = self.window.handle;
1946 self.app.release_listeners.insert(
1947 self.view.model.entity_id,
1948 Box::new(move |this, cx| {
1949 let this = this.downcast_mut().expect("invalid entity type");
1950 let _ = window_handle.update(cx, |_, cx| on_release(this, cx));
1951 }),
1952 )
1953 }
1954
1955 pub fn observe_release<V2, E>(
1956 &mut self,
1957 entity: &E,
1958 mut on_release: impl FnMut(&mut V, &mut V2, &mut ViewContext<'_, V>) + 'static,
1959 ) -> Subscription
1960 where
1961 V: 'static,
1962 V2: 'static,
1963 E: Entity<V2>,
1964 {
1965 let view = self.view().downgrade();
1966 let entity_id = entity.entity_id();
1967 let window_handle = self.window.handle;
1968 self.app.release_listeners.insert(
1969 entity_id,
1970 Box::new(move |entity, cx| {
1971 let entity = entity.downcast_mut().expect("invalid entity type");
1972 let _ = window_handle.update(cx, |_, cx| {
1973 view.update(cx, |this, cx| on_release(this, entity, cx))
1974 });
1975 }),
1976 )
1977 }
1978
1979 pub fn notify(&mut self) {
1980 self.window_cx.notify();
1981 self.window_cx.app.push_effect(Effect::Notify {
1982 emitter: self.view.model.entity_id,
1983 });
1984 }
1985
1986 pub fn observe_window_bounds(
1987 &mut self,
1988 mut callback: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
1989 ) -> Subscription {
1990 let view = self.view.downgrade();
1991 self.window.bounds_observers.insert(
1992 (),
1993 Box::new(move |cx| view.update(cx, |view, cx| callback(view, cx)).is_ok()),
1994 )
1995 }
1996
1997 pub fn observe_window_activation(
1998 &mut self,
1999 mut callback: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2000 ) -> Subscription {
2001 let view = self.view.downgrade();
2002 self.window.activation_observers.insert(
2003 (),
2004 Box::new(move |cx| view.update(cx, |view, cx| callback(view, cx)).is_ok()),
2005 )
2006 }
2007
2008 /// Register a listener to be called when the given focus handle receives focus.
2009 /// Unlike [on_focus_changed], returns a subscription and persists until the subscription
2010 /// is dropped.
2011 pub fn on_focus(
2012 &mut self,
2013 handle: &FocusHandle,
2014 mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2015 ) -> Subscription {
2016 let view = self.view.downgrade();
2017 let focus_id = handle.id;
2018 self.window.focus_listeners.insert(
2019 (),
2020 Box::new(move |event, cx| {
2021 view.update(cx, |view, cx| {
2022 if event.focused.as_ref().map(|focused| focused.id) == Some(focus_id) {
2023 listener(view, cx)
2024 }
2025 })
2026 .is_ok()
2027 }),
2028 )
2029 }
2030
2031 /// Register a listener to be called when the given focus handle or one of its descendants receives focus.
2032 /// Unlike [on_focus_changed], returns a subscription and persists until the subscription
2033 /// is dropped.
2034 pub fn on_focus_in(
2035 &mut self,
2036 handle: &FocusHandle,
2037 mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2038 ) -> Subscription {
2039 let view = self.view.downgrade();
2040 let focus_id = handle.id;
2041 self.window.focus_listeners.insert(
2042 (),
2043 Box::new(move |event, cx| {
2044 view.update(cx, |view, cx| {
2045 if event
2046 .focused
2047 .as_ref()
2048 .map_or(false, |focused| focus_id.contains(focused.id, cx))
2049 {
2050 listener(view, cx)
2051 }
2052 })
2053 .is_ok()
2054 }),
2055 )
2056 }
2057
2058 /// Register a listener to be called when the given focus handle loses focus.
2059 /// Unlike [on_focus_changed], returns a subscription and persists until the subscription
2060 /// is dropped.
2061 pub fn on_blur(
2062 &mut self,
2063 handle: &FocusHandle,
2064 mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2065 ) -> Subscription {
2066 let view = self.view.downgrade();
2067 let focus_id = handle.id;
2068 self.window.focus_listeners.insert(
2069 (),
2070 Box::new(move |event, cx| {
2071 view.update(cx, |view, cx| {
2072 if event.blurred.as_ref().map(|blurred| blurred.id) == Some(focus_id) {
2073 listener(view, cx)
2074 }
2075 })
2076 .is_ok()
2077 }),
2078 )
2079 }
2080
2081 /// Register a listener to be called when the given focus handle or one of its descendants loses focus.
2082 /// Unlike [on_focus_changed], returns a subscription and persists until the subscription
2083 /// is dropped.
2084 pub fn on_focus_out(
2085 &mut self,
2086 handle: &FocusHandle,
2087 mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2088 ) -> Subscription {
2089 let view = self.view.downgrade();
2090 let focus_id = handle.id;
2091 self.window.focus_listeners.insert(
2092 (),
2093 Box::new(move |event, cx| {
2094 view.update(cx, |view, cx| {
2095 if event
2096 .blurred
2097 .as_ref()
2098 .map_or(false, |blurred| focus_id.contains(blurred.id, cx))
2099 {
2100 listener(view, cx)
2101 }
2102 })
2103 .is_ok()
2104 }),
2105 )
2106 }
2107
2108 /// Register a focus listener for the current frame only. It will be cleared
2109 /// on the next frame render. You should use this method only from within elements,
2110 /// and we may want to enforce that better via a different context type.
2111 // todo!() Move this to `FrameContext` to emphasize its individuality?
2112 pub fn on_focus_changed(
2113 &mut self,
2114 listener: impl Fn(&mut V, &FocusEvent, &mut ViewContext<V>) + 'static,
2115 ) {
2116 let handle = self.view().downgrade();
2117 self.window
2118 .current_frame
2119 .focus_listeners
2120 .push(Box::new(move |event, cx| {
2121 handle
2122 .update(cx, |view, cx| listener(view, event, cx))
2123 .log_err();
2124 }));
2125 }
2126
2127 pub fn with_key_dispatch<R>(
2128 &mut self,
2129 context: KeyContext,
2130 focus_handle: Option<FocusHandle>,
2131 f: impl FnOnce(Option<FocusHandle>, &mut Self) -> R,
2132 ) -> R {
2133 let window = &mut self.window;
2134 window
2135 .current_frame
2136 .dispatch_tree
2137 .push_node(context.clone());
2138 if let Some(focus_handle) = focus_handle.as_ref() {
2139 window
2140 .current_frame
2141 .dispatch_tree
2142 .make_focusable(focus_handle.id);
2143 }
2144 let result = f(focus_handle, self);
2145
2146 self.window.current_frame.dispatch_tree.pop_node();
2147
2148 result
2149 }
2150
2151 pub fn spawn<Fut, R>(
2152 &mut self,
2153 f: impl FnOnce(WeakView<V>, AsyncWindowContext) -> Fut,
2154 ) -> Task<R>
2155 where
2156 R: 'static,
2157 Fut: Future<Output = R> + 'static,
2158 {
2159 let view = self.view().downgrade();
2160 self.window_cx.spawn(|cx| f(view, cx))
2161 }
2162
2163 pub fn update_global<G, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R
2164 where
2165 G: 'static,
2166 {
2167 let mut global = self.app.lease_global::<G>();
2168 let result = f(&mut global, self);
2169 self.app.end_global_lease(global);
2170 result
2171 }
2172
2173 pub fn observe_global<G: 'static>(
2174 &mut self,
2175 mut f: impl FnMut(&mut V, &mut ViewContext<'_, V>) + 'static,
2176 ) -> Subscription {
2177 let window_handle = self.window.handle;
2178 let view = self.view().downgrade();
2179 self.global_observers.insert(
2180 TypeId::of::<G>(),
2181 Box::new(move |cx| {
2182 window_handle
2183 .update(cx, |_, cx| view.update(cx, |view, cx| f(view, cx)).is_ok())
2184 .unwrap_or(false)
2185 }),
2186 )
2187 }
2188
2189 pub fn on_mouse_event<Event: 'static>(
2190 &mut self,
2191 handler: impl Fn(&mut V, &Event, DispatchPhase, &mut ViewContext<V>) + 'static,
2192 ) {
2193 let handle = self.view().clone();
2194 self.window_cx.on_mouse_event(move |event, phase, cx| {
2195 handle.update(cx, |view, cx| {
2196 handler(view, event, phase, cx);
2197 })
2198 });
2199 }
2200
2201 pub fn on_key_event<Event: 'static>(
2202 &mut self,
2203 handler: impl Fn(&mut V, &Event, DispatchPhase, &mut ViewContext<V>) + 'static,
2204 ) {
2205 let handle = self.view().clone();
2206 self.window_cx.on_key_event(move |event, phase, cx| {
2207 handle.update(cx, |view, cx| {
2208 handler(view, event, phase, cx);
2209 })
2210 });
2211 }
2212
2213 pub fn on_action(
2214 &mut self,
2215 action_type: TypeId,
2216 handler: impl Fn(&mut V, &dyn Any, DispatchPhase, &mut ViewContext<V>) + 'static,
2217 ) {
2218 let handle = self.view().clone();
2219 self.window_cx
2220 .on_action(action_type, move |action, phase, cx| {
2221 handle.update(cx, |view, cx| {
2222 handler(view, action, phase, cx);
2223 })
2224 });
2225 }
2226
2227 /// Set an input handler, such as [ElementInputHandler], which interfaces with the
2228 /// platform to receive textual input with proper integration with concerns such
2229 /// as IME interactions.
2230 pub fn handle_input(
2231 &mut self,
2232 focus_handle: &FocusHandle,
2233 input_handler: impl PlatformInputHandler,
2234 ) {
2235 if focus_handle.is_focused(self) {
2236 self.window
2237 .platform_window
2238 .set_input_handler(Box::new(input_handler));
2239 }
2240 }
2241
2242 pub fn emit<Evt>(&mut self, event: Evt)
2243 where
2244 Evt: 'static,
2245 V: EventEmitter<Evt>,
2246 {
2247 let emitter = self.view.model.entity_id;
2248 self.app.push_effect(Effect::Emit {
2249 emitter,
2250 event_type: TypeId::of::<Evt>(),
2251 event: Box::new(event),
2252 });
2253 }
2254
2255 pub fn focus_self(&mut self)
2256 where
2257 V: FocusableView,
2258 {
2259 self.defer(|view, cx| view.focus_handle(cx).focus(cx))
2260 }
2261}
2262
2263impl<V> Context for ViewContext<'_, V> {
2264 type Result<U> = U;
2265
2266 fn build_model<T: 'static>(
2267 &mut self,
2268 build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
2269 ) -> Model<T> {
2270 self.window_cx.build_model(build_model)
2271 }
2272
2273 fn update_model<T: 'static, R>(
2274 &mut self,
2275 model: &Model<T>,
2276 update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
2277 ) -> R {
2278 self.window_cx.update_model(model, update)
2279 }
2280
2281 fn update_window<T, F>(&mut self, window: AnyWindowHandle, update: F) -> Result<T>
2282 where
2283 F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
2284 {
2285 self.window_cx.update_window(window, update)
2286 }
2287
2288 fn read_model<T, R>(
2289 &self,
2290 handle: &Model<T>,
2291 read: impl FnOnce(&T, &AppContext) -> R,
2292 ) -> Self::Result<R>
2293 where
2294 T: 'static,
2295 {
2296 self.window_cx.read_model(handle, read)
2297 }
2298
2299 fn read_window<T, R>(
2300 &self,
2301 window: &WindowHandle<T>,
2302 read: impl FnOnce(View<T>, &AppContext) -> R,
2303 ) -> Result<R>
2304 where
2305 T: 'static,
2306 {
2307 self.window_cx.read_window(window, read)
2308 }
2309}
2310
2311impl<V: 'static> VisualContext for ViewContext<'_, V> {
2312 fn build_view<W: Render + 'static>(
2313 &mut self,
2314 build_view_state: impl FnOnce(&mut ViewContext<'_, W>) -> W,
2315 ) -> Self::Result<View<W>> {
2316 self.window_cx.build_view(build_view_state)
2317 }
2318
2319 fn update_view<V2: 'static, R>(
2320 &mut self,
2321 view: &View<V2>,
2322 update: impl FnOnce(&mut V2, &mut ViewContext<'_, V2>) -> R,
2323 ) -> Self::Result<R> {
2324 self.window_cx.update_view(view, update)
2325 }
2326
2327 fn replace_root_view<W>(
2328 &mut self,
2329 build_view: impl FnOnce(&mut ViewContext<'_, W>) -> W,
2330 ) -> Self::Result<View<W>>
2331 where
2332 W: Render,
2333 {
2334 self.window_cx.replace_root_view(build_view)
2335 }
2336
2337 fn focus_view<W: FocusableView>(&mut self, view: &View<W>) -> Self::Result<()> {
2338 self.window_cx.focus_view(view)
2339 }
2340}
2341
2342impl<'a, V> std::ops::Deref for ViewContext<'a, V> {
2343 type Target = WindowContext<'a>;
2344
2345 fn deref(&self) -> &Self::Target {
2346 &self.window_cx
2347 }
2348}
2349
2350impl<'a, V> std::ops::DerefMut for ViewContext<'a, V> {
2351 fn deref_mut(&mut self) -> &mut Self::Target {
2352 &mut self.window_cx
2353 }
2354}
2355
2356// #[derive(Clone, Copy, Eq, PartialEq, Hash)]
2357slotmap::new_key_type! { pub struct WindowId; }
2358
2359impl WindowId {
2360 pub fn as_u64(&self) -> u64 {
2361 self.0.as_ffi()
2362 }
2363}
2364
2365#[derive(Deref, DerefMut)]
2366pub struct WindowHandle<V> {
2367 #[deref]
2368 #[deref_mut]
2369 pub(crate) any_handle: AnyWindowHandle,
2370 state_type: PhantomData<V>,
2371}
2372
2373impl<V: 'static + Render> WindowHandle<V> {
2374 pub fn new(id: WindowId) -> Self {
2375 WindowHandle {
2376 any_handle: AnyWindowHandle {
2377 id,
2378 state_type: TypeId::of::<V>(),
2379 },
2380 state_type: PhantomData,
2381 }
2382 }
2383
2384 pub fn update<C, R>(
2385 &self,
2386 cx: &mut C,
2387 update: impl FnOnce(&mut V, &mut ViewContext<'_, V>) -> R,
2388 ) -> Result<R>
2389 where
2390 C: Context,
2391 {
2392 cx.update_window(self.any_handle, |root_view, cx| {
2393 let view = root_view
2394 .downcast::<V>()
2395 .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
2396 Ok(cx.update_view(&view, update))
2397 })?
2398 }
2399
2400 pub fn read<'a>(&self, cx: &'a AppContext) -> Result<&'a V> {
2401 let x = cx
2402 .windows
2403 .get(self.id)
2404 .and_then(|window| {
2405 window
2406 .as_ref()
2407 .and_then(|window| window.root_view.clone())
2408 .map(|root_view| root_view.downcast::<V>())
2409 })
2410 .ok_or_else(|| anyhow!("window not found"))?
2411 .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
2412
2413 Ok(x.read(cx))
2414 }
2415
2416 pub fn read_with<C, R>(&self, cx: &C, read_with: impl FnOnce(&V, &AppContext) -> R) -> Result<R>
2417 where
2418 C: Context,
2419 {
2420 cx.read_window(self, |root_view, cx| read_with(root_view.read(cx), cx))
2421 }
2422
2423 pub fn root_view<C>(&self, cx: &C) -> Result<View<V>>
2424 where
2425 C: Context,
2426 {
2427 cx.read_window(self, |root_view, _cx| root_view.clone())
2428 }
2429
2430 pub fn is_active(&self, cx: &WindowContext) -> Option<bool> {
2431 cx.windows
2432 .get(self.id)
2433 .and_then(|window| window.as_ref().map(|window| window.active))
2434 }
2435}
2436
2437impl<V> Copy for WindowHandle<V> {}
2438
2439impl<V> Clone for WindowHandle<V> {
2440 fn clone(&self) -> Self {
2441 WindowHandle {
2442 any_handle: self.any_handle,
2443 state_type: PhantomData,
2444 }
2445 }
2446}
2447
2448impl<V> PartialEq for WindowHandle<V> {
2449 fn eq(&self, other: &Self) -> bool {
2450 self.any_handle == other.any_handle
2451 }
2452}
2453
2454impl<V> Eq for WindowHandle<V> {}
2455
2456impl<V> Hash for WindowHandle<V> {
2457 fn hash<H: Hasher>(&self, state: &mut H) {
2458 self.any_handle.hash(state);
2459 }
2460}
2461
2462impl<V: 'static> Into<AnyWindowHandle> for WindowHandle<V> {
2463 fn into(self) -> AnyWindowHandle {
2464 self.any_handle
2465 }
2466}
2467
2468#[derive(Copy, Clone, PartialEq, Eq, Hash)]
2469pub struct AnyWindowHandle {
2470 pub(crate) id: WindowId,
2471 state_type: TypeId,
2472}
2473
2474impl AnyWindowHandle {
2475 pub fn window_id(&self) -> WindowId {
2476 self.id
2477 }
2478
2479 pub fn downcast<T: 'static>(&self) -> Option<WindowHandle<T>> {
2480 if TypeId::of::<T>() == self.state_type {
2481 Some(WindowHandle {
2482 any_handle: *self,
2483 state_type: PhantomData,
2484 })
2485 } else {
2486 None
2487 }
2488 }
2489
2490 pub fn update<C, R>(
2491 self,
2492 cx: &mut C,
2493 update: impl FnOnce(AnyView, &mut WindowContext<'_>) -> R,
2494 ) -> Result<R>
2495 where
2496 C: Context,
2497 {
2498 cx.update_window(self, update)
2499 }
2500
2501 pub fn read<T, C, R>(self, cx: &C, read: impl FnOnce(View<T>, &AppContext) -> R) -> Result<R>
2502 where
2503 C: Context,
2504 T: 'static,
2505 {
2506 let view = self
2507 .downcast::<T>()
2508 .context("the type of the window's root view has changed")?;
2509
2510 cx.read_window(&view, read)
2511 }
2512}
2513
2514#[cfg(any(test, feature = "test-support"))]
2515impl From<SmallVec<[u32; 16]>> for StackingOrder {
2516 fn from(small_vec: SmallVec<[u32; 16]>) -> Self {
2517 StackingOrder(small_vec)
2518 }
2519}
2520
2521#[derive(Clone, Debug, Eq, PartialEq, Hash)]
2522pub enum ElementId {
2523 View(EntityId),
2524 Integer(usize),
2525 Name(SharedString),
2526 FocusHandle(FocusId),
2527}
2528
2529impl From<EntityId> for ElementId {
2530 fn from(id: EntityId) -> Self {
2531 ElementId::View(id)
2532 }
2533}
2534
2535impl From<usize> for ElementId {
2536 fn from(id: usize) -> Self {
2537 ElementId::Integer(id)
2538 }
2539}
2540
2541impl From<i32> for ElementId {
2542 fn from(id: i32) -> Self {
2543 Self::Integer(id as usize)
2544 }
2545}
2546
2547impl From<SharedString> for ElementId {
2548 fn from(name: SharedString) -> Self {
2549 ElementId::Name(name)
2550 }
2551}
2552
2553impl From<&'static str> for ElementId {
2554 fn from(name: &'static str) -> Self {
2555 ElementId::Name(name.into())
2556 }
2557}
2558
2559impl<'a> From<&'a FocusHandle> for ElementId {
2560 fn from(handle: &'a FocusHandle) -> Self {
2561 ElementId::FocusHandle(handle.id)
2562 }
2563}