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