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 /// Sets the size of an em for the base font of the application. Adjusting this value allows the
545 /// UI to scale, just like zooming a web page.
546 pub fn set_rem_size(&mut self, rem_size: impl Into<Pixels>) {
547 self.window.rem_size = rem_size.into();
548 }
549
550 /// The line height associated with the current text style.
551 pub fn line_height(&self) -> Pixels {
552 let rem_size = self.rem_size();
553 let text_style = self.text_style();
554 text_style
555 .line_height
556 .to_pixels(text_style.font_size.into(), rem_size)
557 }
558
559 /// Call to prevent the default action of an event. Currently only used to prevent
560 /// parent elements from becoming focused on mouse down.
561 pub fn prevent_default(&mut self) {
562 self.window.default_prevented = true;
563 }
564
565 /// Obtain whether default has been prevented for the event currently being dispatched.
566 pub fn default_prevented(&self) -> bool {
567 self.window.default_prevented
568 }
569
570 /// Register a mouse event listener on the window for the current frame. The type of event
571 /// is determined by the first parameter of the given listener. When the next frame is rendered
572 /// the listener will be cleared.
573 ///
574 /// This is a fairly low-level method, so prefer using event handlers on elements unless you have
575 /// a specific need to register a global listener.
576 pub fn on_mouse_event<Event: 'static>(
577 &mut self,
578 handler: impl Fn(&Event, DispatchPhase, &mut WindowContext) + Send + 'static,
579 ) {
580 let order = self.window.z_index_stack.clone();
581 self.window
582 .mouse_listeners
583 .entry(TypeId::of::<Event>())
584 .or_default()
585 .push((
586 order,
587 Box::new(move |event: &dyn Any, phase, cx| {
588 handler(event.downcast_ref().unwrap(), phase, cx)
589 }),
590 ))
591 }
592
593 /// The position of the mouse relative to the window.
594 pub fn mouse_position(&self) -> Point<Pixels> {
595 self.window.mouse_position
596 }
597
598 /// Called during painting to invoke the given closure in a new stacking context. The given
599 /// z-index is interpreted relative to the previous call to `stack`.
600 pub fn stack<R>(&mut self, z_index: u32, f: impl FnOnce(&mut Self) -> R) -> R {
601 self.window.z_index_stack.push(z_index);
602 let result = f(self);
603 self.window.z_index_stack.pop();
604 result
605 }
606
607 /// Paint one or more drop shadows into the scene for the current frame at the current z-index.
608 pub fn paint_shadows(
609 &mut self,
610 bounds: Bounds<Pixels>,
611 corner_radii: Corners<Pixels>,
612 shadows: &[BoxShadow],
613 ) {
614 let scale_factor = self.scale_factor();
615 let content_mask = self.content_mask();
616 let window = &mut *self.window;
617 for shadow in shadows {
618 let mut shadow_bounds = bounds;
619 shadow_bounds.origin += shadow.offset;
620 shadow_bounds.dilate(shadow.spread_radius);
621 window.scene_builder.insert(
622 &window.z_index_stack,
623 Shadow {
624 order: 0,
625 bounds: shadow_bounds.scale(scale_factor),
626 content_mask: content_mask.scale(scale_factor),
627 corner_radii: corner_radii.scale(scale_factor),
628 color: shadow.color,
629 blur_radius: shadow.blur_radius.scale(scale_factor),
630 },
631 );
632 }
633 }
634
635 /// Paint one or more quads into the scene for the current frame at the current stacking context.
636 /// Quads are colored rectangular regions with an optional background, border, and corner radius.
637 pub fn paint_quad(
638 &mut self,
639 bounds: Bounds<Pixels>,
640 corner_radii: Corners<Pixels>,
641 background: impl Into<Hsla>,
642 border_widths: Edges<Pixels>,
643 border_color: impl Into<Hsla>,
644 ) {
645 let scale_factor = self.scale_factor();
646 let content_mask = self.content_mask();
647
648 let window = &mut *self.window;
649 window.scene_builder.insert(
650 &window.z_index_stack,
651 Quad {
652 order: 0,
653 bounds: bounds.scale(scale_factor),
654 content_mask: content_mask.scale(scale_factor),
655 background: background.into(),
656 border_color: border_color.into(),
657 corner_radii: corner_radii.scale(scale_factor),
658 border_widths: border_widths.scale(scale_factor),
659 },
660 );
661 }
662
663 /// Paint the given `Path` into the scene for the current frame at the current z-index.
664 pub fn paint_path(&mut self, mut path: Path<Pixels>, color: impl Into<Hsla>) {
665 let scale_factor = self.scale_factor();
666 let content_mask = self.content_mask();
667 path.content_mask = content_mask;
668 path.color = color.into();
669 let window = &mut *self.window;
670 window
671 .scene_builder
672 .insert(&window.z_index_stack, path.scale(scale_factor));
673 }
674
675 /// Paint an underline into the scene for the current frame at the current z-index.
676 pub fn paint_underline(
677 &mut self,
678 origin: Point<Pixels>,
679 width: Pixels,
680 style: &UnderlineStyle,
681 ) -> Result<()> {
682 let scale_factor = self.scale_factor();
683 let height = if style.wavy {
684 style.thickness * 3.
685 } else {
686 style.thickness
687 };
688 let bounds = Bounds {
689 origin,
690 size: size(width, height),
691 };
692 let content_mask = self.content_mask();
693 let window = &mut *self.window;
694 window.scene_builder.insert(
695 &window.z_index_stack,
696 Underline {
697 order: 0,
698 bounds: bounds.scale(scale_factor),
699 content_mask: content_mask.scale(scale_factor),
700 thickness: style.thickness.scale(scale_factor),
701 color: style.color.unwrap_or_default(),
702 wavy: style.wavy,
703 },
704 );
705 Ok(())
706 }
707
708 /// Paint a monochrome (non-emoji) glyph into the scene for the current frame at the current z-index.
709 pub fn paint_glyph(
710 &mut self,
711 origin: Point<Pixels>,
712 font_id: FontId,
713 glyph_id: GlyphId,
714 font_size: Pixels,
715 color: Hsla,
716 ) -> Result<()> {
717 let scale_factor = self.scale_factor();
718 let glyph_origin = origin.scale(scale_factor);
719 let subpixel_variant = Point {
720 x: (glyph_origin.x.0.fract() * SUBPIXEL_VARIANTS as f32).floor() as u8,
721 y: (glyph_origin.y.0.fract() * SUBPIXEL_VARIANTS as f32).floor() as u8,
722 };
723 let params = RenderGlyphParams {
724 font_id,
725 glyph_id,
726 font_size,
727 subpixel_variant,
728 scale_factor,
729 is_emoji: false,
730 };
731
732 let raster_bounds = self.text_system().raster_bounds(¶ms)?;
733 if !raster_bounds.is_zero() {
734 let tile =
735 self.window
736 .sprite_atlas
737 .get_or_insert_with(¶ms.clone().into(), &mut || {
738 let (size, bytes) = self.text_system().rasterize_glyph(¶ms)?;
739 Ok((size, Cow::Owned(bytes)))
740 })?;
741 let bounds = Bounds {
742 origin: glyph_origin.map(|px| px.floor()) + raster_bounds.origin.map(Into::into),
743 size: tile.bounds.size.map(Into::into),
744 };
745 let content_mask = self.content_mask().scale(scale_factor);
746 let window = &mut *self.window;
747 window.scene_builder.insert(
748 &window.z_index_stack,
749 MonochromeSprite {
750 order: 0,
751 bounds,
752 content_mask,
753 color,
754 tile,
755 },
756 );
757 }
758 Ok(())
759 }
760
761 /// Paint an emoji glyph into the scene for the current frame at the current z-index.
762 pub fn paint_emoji(
763 &mut self,
764 origin: Point<Pixels>,
765 font_id: FontId,
766 glyph_id: GlyphId,
767 font_size: Pixels,
768 ) -> Result<()> {
769 let scale_factor = self.scale_factor();
770 let glyph_origin = origin.scale(scale_factor);
771 let params = RenderGlyphParams {
772 font_id,
773 glyph_id,
774 font_size,
775 // We don't render emojis with subpixel variants.
776 subpixel_variant: Default::default(),
777 scale_factor,
778 is_emoji: true,
779 };
780
781 let raster_bounds = self.text_system().raster_bounds(¶ms)?;
782 if !raster_bounds.is_zero() {
783 let tile =
784 self.window
785 .sprite_atlas
786 .get_or_insert_with(¶ms.clone().into(), &mut || {
787 let (size, bytes) = self.text_system().rasterize_glyph(¶ms)?;
788 Ok((size, Cow::Owned(bytes)))
789 })?;
790 let bounds = Bounds {
791 origin: glyph_origin.map(|px| px.floor()) + raster_bounds.origin.map(Into::into),
792 size: tile.bounds.size.map(Into::into),
793 };
794 let content_mask = self.content_mask().scale(scale_factor);
795 let window = &mut *self.window;
796
797 window.scene_builder.insert(
798 &window.z_index_stack,
799 PolychromeSprite {
800 order: 0,
801 bounds,
802 corner_radii: Default::default(),
803 content_mask,
804 tile,
805 grayscale: false,
806 },
807 );
808 }
809 Ok(())
810 }
811
812 /// Paint a monochrome SVG into the scene for the current frame at the current stacking context.
813 pub fn paint_svg(
814 &mut self,
815 bounds: Bounds<Pixels>,
816 path: SharedString,
817 color: Hsla,
818 ) -> Result<()> {
819 let scale_factor = self.scale_factor();
820 let bounds = bounds.scale(scale_factor);
821 // Render the SVG at twice the size to get a higher quality result.
822 let params = RenderSvgParams {
823 path,
824 size: bounds
825 .size
826 .map(|pixels| DevicePixels::from((pixels.0 * 2.).ceil() as i32)),
827 };
828
829 let tile =
830 self.window
831 .sprite_atlas
832 .get_or_insert_with(¶ms.clone().into(), &mut || {
833 let bytes = self.svg_renderer.render(¶ms)?;
834 Ok((params.size, Cow::Owned(bytes)))
835 })?;
836 let content_mask = self.content_mask().scale(scale_factor);
837
838 let window = &mut *self.window;
839 window.scene_builder.insert(
840 &window.z_index_stack,
841 MonochromeSprite {
842 order: 0,
843 bounds,
844 content_mask,
845 color,
846 tile,
847 },
848 );
849
850 Ok(())
851 }
852
853 /// Paint an image into the scene for the current frame at the current z-index.
854 pub fn paint_image(
855 &mut self,
856 bounds: Bounds<Pixels>,
857 corner_radii: Corners<Pixels>,
858 data: Arc<ImageData>,
859 grayscale: bool,
860 ) -> Result<()> {
861 let scale_factor = self.scale_factor();
862 let bounds = bounds.scale(scale_factor);
863 let params = RenderImageParams { image_id: data.id };
864
865 let tile = self
866 .window
867 .sprite_atlas
868 .get_or_insert_with(¶ms.clone().into(), &mut || {
869 Ok((data.size(), Cow::Borrowed(data.as_bytes())))
870 })?;
871 let content_mask = self.content_mask().scale(scale_factor);
872 let corner_radii = corner_radii.scale(scale_factor);
873
874 let window = &mut *self.window;
875 window.scene_builder.insert(
876 &window.z_index_stack,
877 PolychromeSprite {
878 order: 0,
879 bounds,
880 content_mask,
881 corner_radii,
882 tile,
883 grayscale,
884 },
885 );
886 Ok(())
887 }
888
889 /// Draw pixels to the display for this window based on the contents of its scene.
890 pub(crate) fn draw(&mut self) {
891 let root_view = self.window.root_view.take().unwrap();
892
893 self.start_frame();
894
895 self.stack(0, |cx| {
896 let available_space = cx.window.content_size.map(Into::into);
897 root_view.draw(available_space, cx);
898 });
899
900 if let Some(active_drag) = self.app.active_drag.take() {
901 self.stack(1, |cx| {
902 let offset = cx.mouse_position() - active_drag.cursor_offset;
903 cx.with_element_offset(Some(offset), |cx| {
904 let available_space =
905 size(AvailableSpace::MinContent, AvailableSpace::MinContent);
906 active_drag.view.draw(available_space, cx);
907 cx.active_drag = Some(active_drag);
908 });
909 });
910 }
911
912 self.window.root_view = Some(root_view);
913 let scene = self.window.scene_builder.build();
914
915 self.run_on_main(|cx| {
916 cx.window
917 .platform_window
918 .borrow_on_main_thread()
919 .draw(scene);
920 cx.window.dirty = false;
921 })
922 .detach();
923 }
924
925 fn start_frame(&mut self) {
926 self.text_system().start_frame();
927
928 let window = &mut *self.window;
929
930 // Move the current frame element states to the previous frame.
931 // The new empty element states map will be populated for any element states we
932 // reference during the upcoming frame.
933 mem::swap(
934 &mut window.element_states,
935 &mut window.prev_frame_element_states,
936 );
937 window.element_states.clear();
938
939 // Make the current key matchers the previous, and then clear the current.
940 // An empty key matcher map will be created for every identified element in the
941 // upcoming frame.
942 mem::swap(
943 &mut window.key_matchers,
944 &mut window.prev_frame_key_matchers,
945 );
946 window.key_matchers.clear();
947
948 // Clear mouse event listeners, because elements add new element listeners
949 // when the upcoming frame is painted.
950 window.mouse_listeners.values_mut().for_each(Vec::clear);
951
952 // Clear focus state, because we determine what is focused when the new elements
953 // in the upcoming frame are initialized.
954 window.focus_listeners.clear();
955 window.key_dispatch_stack.clear();
956 window.focus_parents_by_child.clear();
957 window.freeze_key_dispatch_stack = false;
958 }
959
960 /// Dispatch a mouse or keyboard event on the window.
961 fn dispatch_event(&mut self, event: InputEvent) -> bool {
962 let event = match event {
963 // Track the mouse position with our own state, since accessing the platform
964 // API for the mouse position can only occur on the main thread.
965 InputEvent::MouseMove(mouse_move) => {
966 self.window.mouse_position = mouse_move.position;
967 InputEvent::MouseMove(mouse_move)
968 }
969 // Translate dragging and dropping of external files from the operating system
970 // to internal drag and drop events.
971 InputEvent::FileDrop(file_drop) => match file_drop {
972 FileDropEvent::Entered { position, files } => {
973 self.window.mouse_position = position;
974 if self.active_drag.is_none() {
975 self.active_drag = Some(AnyDrag {
976 view: self.build_view(|_| files).into(),
977 cursor_offset: position,
978 });
979 }
980 InputEvent::MouseDown(MouseDownEvent {
981 position,
982 button: MouseButton::Left,
983 click_count: 1,
984 modifiers: Modifiers::default(),
985 })
986 }
987 FileDropEvent::Pending { position } => {
988 self.window.mouse_position = position;
989 InputEvent::MouseMove(MouseMoveEvent {
990 position,
991 pressed_button: Some(MouseButton::Left),
992 modifiers: Modifiers::default(),
993 })
994 }
995 FileDropEvent::Submit { position } => {
996 self.window.mouse_position = position;
997 InputEvent::MouseUp(MouseUpEvent {
998 button: MouseButton::Left,
999 position,
1000 modifiers: Modifiers::default(),
1001 click_count: 1,
1002 })
1003 }
1004 FileDropEvent::Exited => InputEvent::MouseUp(MouseUpEvent {
1005 button: MouseButton::Left,
1006 position: Point::default(),
1007 modifiers: Modifiers::default(),
1008 click_count: 1,
1009 }),
1010 },
1011 _ => event,
1012 };
1013
1014 if let Some(any_mouse_event) = event.mouse_event() {
1015 // Handlers may set this to false by calling `stop_propagation`
1016 self.app.propagate_event = true;
1017 self.window.default_prevented = false;
1018
1019 if let Some(mut handlers) = self
1020 .window
1021 .mouse_listeners
1022 .remove(&any_mouse_event.type_id())
1023 {
1024 // Because handlers may add other handlers, we sort every time.
1025 handlers.sort_by(|(a, _), (b, _)| a.cmp(b));
1026
1027 // Capture phase, events bubble from back to front. Handlers for this phase are used for
1028 // special purposes, such as detecting events outside of a given Bounds.
1029 for (_, handler) in &handlers {
1030 handler(any_mouse_event, DispatchPhase::Capture, self);
1031 if !self.app.propagate_event {
1032 break;
1033 }
1034 }
1035
1036 // Bubble phase, where most normal handlers do their work.
1037 if self.app.propagate_event {
1038 for (_, handler) in handlers.iter().rev() {
1039 handler(any_mouse_event, DispatchPhase::Bubble, self);
1040 if !self.app.propagate_event {
1041 break;
1042 }
1043 }
1044 }
1045
1046 if self.app.propagate_event
1047 && any_mouse_event.downcast_ref::<MouseUpEvent>().is_some()
1048 {
1049 self.active_drag = None;
1050 }
1051
1052 // Just in case any handlers added new handlers, which is weird, but possible.
1053 handlers.extend(
1054 self.window
1055 .mouse_listeners
1056 .get_mut(&any_mouse_event.type_id())
1057 .into_iter()
1058 .flat_map(|handlers| handlers.drain(..)),
1059 );
1060 self.window
1061 .mouse_listeners
1062 .insert(any_mouse_event.type_id(), handlers);
1063 }
1064 } else if let Some(any_key_event) = event.keyboard_event() {
1065 let key_dispatch_stack = mem::take(&mut self.window.key_dispatch_stack);
1066 let key_event_type = any_key_event.type_id();
1067 let mut context_stack = SmallVec::<[&DispatchContext; 16]>::new();
1068
1069 for (ix, frame) in key_dispatch_stack.iter().enumerate() {
1070 match frame {
1071 KeyDispatchStackFrame::Listener {
1072 event_type,
1073 listener,
1074 } => {
1075 if key_event_type == *event_type {
1076 if let Some(action) = listener(
1077 any_key_event,
1078 &context_stack,
1079 DispatchPhase::Capture,
1080 self,
1081 ) {
1082 self.dispatch_action(action, &key_dispatch_stack[..ix]);
1083 }
1084 if !self.app.propagate_event {
1085 break;
1086 }
1087 }
1088 }
1089 KeyDispatchStackFrame::Context(context) => {
1090 context_stack.push(&context);
1091 }
1092 }
1093 }
1094
1095 if self.app.propagate_event {
1096 for (ix, frame) in key_dispatch_stack.iter().enumerate().rev() {
1097 match frame {
1098 KeyDispatchStackFrame::Listener {
1099 event_type,
1100 listener,
1101 } => {
1102 if key_event_type == *event_type {
1103 if let Some(action) = listener(
1104 any_key_event,
1105 &context_stack,
1106 DispatchPhase::Bubble,
1107 self,
1108 ) {
1109 self.dispatch_action(action, &key_dispatch_stack[..ix]);
1110 }
1111
1112 if !self.app.propagate_event {
1113 break;
1114 }
1115 }
1116 }
1117 KeyDispatchStackFrame::Context(_) => {
1118 context_stack.pop();
1119 }
1120 }
1121 }
1122 }
1123
1124 drop(context_stack);
1125 self.window.key_dispatch_stack = key_dispatch_stack;
1126 }
1127
1128 true
1129 }
1130
1131 /// Attempt to map a keystroke to an action based on the keymap.
1132 pub fn match_keystroke(
1133 &mut self,
1134 element_id: &GlobalElementId,
1135 keystroke: &Keystroke,
1136 context_stack: &[&DispatchContext],
1137 ) -> KeyMatch {
1138 let key_match = self
1139 .window
1140 .key_matchers
1141 .get_mut(element_id)
1142 .unwrap()
1143 .match_keystroke(keystroke, context_stack);
1144
1145 if key_match.is_some() {
1146 for matcher in self.window.key_matchers.values_mut() {
1147 matcher.clear_pending();
1148 }
1149 }
1150
1151 key_match
1152 }
1153
1154 /// Register the given handler to be invoked whenever the global of the given type
1155 /// is updated.
1156 pub fn observe_global<G: 'static>(
1157 &mut self,
1158 f: impl Fn(&mut WindowContext<'_, '_>) + Send + 'static,
1159 ) -> Subscription {
1160 let window_id = self.window.handle.id;
1161 self.global_observers.insert(
1162 TypeId::of::<G>(),
1163 Box::new(move |cx| cx.update_window(window_id, |cx| f(cx)).is_ok()),
1164 )
1165 }
1166
1167 fn dispatch_action(
1168 &mut self,
1169 action: Box<dyn Action>,
1170 dispatch_stack: &[KeyDispatchStackFrame],
1171 ) {
1172 let action_type = action.as_any().type_id();
1173
1174 if let Some(mut global_listeners) = self.app.global_action_listeners.remove(&action_type) {
1175 for listener in &global_listeners {
1176 listener(action.as_ref(), DispatchPhase::Capture, self);
1177 if !self.app.propagate_event {
1178 break;
1179 }
1180 }
1181 global_listeners.extend(
1182 self.global_action_listeners
1183 .remove(&action_type)
1184 .unwrap_or_default(),
1185 );
1186 self.global_action_listeners
1187 .insert(action_type, global_listeners);
1188 }
1189
1190 if self.app.propagate_event {
1191 for stack_frame in dispatch_stack {
1192 if let KeyDispatchStackFrame::Listener {
1193 event_type,
1194 listener,
1195 } = stack_frame
1196 {
1197 if action_type == *event_type {
1198 listener(action.as_any(), &[], DispatchPhase::Capture, self);
1199 if !self.app.propagate_event {
1200 break;
1201 }
1202 }
1203 }
1204 }
1205 }
1206
1207 if self.app.propagate_event {
1208 for stack_frame in dispatch_stack.iter().rev() {
1209 if let KeyDispatchStackFrame::Listener {
1210 event_type,
1211 listener,
1212 } = stack_frame
1213 {
1214 if action_type == *event_type {
1215 listener(action.as_any(), &[], DispatchPhase::Bubble, self);
1216 if !self.app.propagate_event {
1217 break;
1218 }
1219 }
1220 }
1221 }
1222 }
1223
1224 if self.app.propagate_event {
1225 if let Some(mut global_listeners) =
1226 self.app.global_action_listeners.remove(&action_type)
1227 {
1228 for listener in global_listeners.iter().rev() {
1229 listener(action.as_ref(), DispatchPhase::Bubble, self);
1230 if !self.app.propagate_event {
1231 break;
1232 }
1233 }
1234 global_listeners.extend(
1235 self.global_action_listeners
1236 .remove(&action_type)
1237 .unwrap_or_default(),
1238 );
1239 self.global_action_listeners
1240 .insert(action_type, global_listeners);
1241 }
1242 }
1243 }
1244}
1245
1246impl Context for WindowContext<'_, '_> {
1247 type ModelContext<'a, T> = ModelContext<'a, T>;
1248 type Result<T> = T;
1249
1250 fn build_model<T>(
1251 &mut self,
1252 build_model: impl FnOnce(&mut Self::ModelContext<'_, T>) -> T,
1253 ) -> Model<T>
1254 where
1255 T: 'static + Send,
1256 {
1257 let slot = self.app.entities.reserve();
1258 let model = build_model(&mut ModelContext::mutable(&mut *self.app, slot.downgrade()));
1259 self.entities.insert(slot, model)
1260 }
1261
1262 fn update_model<T: 'static, R>(
1263 &mut self,
1264 model: &Model<T>,
1265 update: impl FnOnce(&mut T, &mut Self::ModelContext<'_, T>) -> R,
1266 ) -> R {
1267 let mut entity = self.entities.lease(model);
1268 let result = update(
1269 &mut *entity,
1270 &mut ModelContext::mutable(&mut *self.app, model.downgrade()),
1271 );
1272 self.entities.end_lease(entity);
1273 result
1274 }
1275}
1276
1277impl VisualContext for WindowContext<'_, '_> {
1278 type ViewContext<'a, 'w, V> = ViewContext<'a, 'w, V>;
1279
1280 fn build_view<V>(
1281 &mut self,
1282 build_view_state: impl FnOnce(&mut Self::ViewContext<'_, '_, V>) -> V,
1283 ) -> Self::Result<View<V>>
1284 where
1285 V: 'static + Send,
1286 {
1287 let slot = self.app.entities.reserve();
1288 let view = View {
1289 model: slot.clone(),
1290 };
1291 let mut cx = ViewContext::mutable(&mut *self.app, &mut *self.window, view.downgrade());
1292 let entity = build_view_state(&mut cx);
1293 self.entities.insert(slot, entity);
1294 view
1295 }
1296
1297 /// Update the given view. Prefer calling `View::update` instead, which calls this method.
1298 fn update_view<T: 'static, R>(
1299 &mut self,
1300 view: &View<T>,
1301 update: impl FnOnce(&mut T, &mut Self::ViewContext<'_, '_, T>) -> R,
1302 ) -> Self::Result<R> {
1303 let mut lease = self.app.entities.lease(&view.model);
1304 let mut cx = ViewContext::mutable(&mut *self.app, &mut *self.window, view.downgrade());
1305 let result = update(&mut *lease, &mut cx);
1306 cx.app.entities.end_lease(lease);
1307 result
1308 }
1309}
1310
1311impl<'a, 'w> std::ops::Deref for WindowContext<'a, 'w> {
1312 type Target = AppContext;
1313
1314 fn deref(&self) -> &Self::Target {
1315 &self.app
1316 }
1317}
1318
1319impl<'a, 'w> std::ops::DerefMut for WindowContext<'a, 'w> {
1320 fn deref_mut(&mut self) -> &mut Self::Target {
1321 &mut self.app
1322 }
1323}
1324
1325impl<'a, 'w> Borrow<AppContext> for WindowContext<'a, 'w> {
1326 fn borrow(&self) -> &AppContext {
1327 &self.app
1328 }
1329}
1330
1331impl<'a, 'w> BorrowMut<AppContext> for WindowContext<'a, 'w> {
1332 fn borrow_mut(&mut self) -> &mut AppContext {
1333 &mut self.app
1334 }
1335}
1336
1337pub trait BorrowWindow: BorrowMut<Window> + BorrowMut<AppContext> {
1338 fn app_mut(&mut self) -> &mut AppContext {
1339 self.borrow_mut()
1340 }
1341
1342 fn window(&self) -> &Window {
1343 self.borrow()
1344 }
1345
1346 fn window_mut(&mut self) -> &mut Window {
1347 self.borrow_mut()
1348 }
1349
1350 /// Pushes the given element id onto the global stack and invokes the given closure
1351 /// with a `GlobalElementId`, which disambiguates the given id in the context of its ancestor
1352 /// ids. Because elements are discarded and recreated on each frame, the `GlobalElementId` is
1353 /// used to associate state with identified elements across separate frames.
1354 fn with_element_id<R>(
1355 &mut self,
1356 id: impl Into<ElementId>,
1357 f: impl FnOnce(GlobalElementId, &mut Self) -> R,
1358 ) -> R {
1359 let keymap = self.app_mut().keymap.clone();
1360 let window = self.window_mut();
1361 window.element_id_stack.push(id.into());
1362 let global_id = window.element_id_stack.clone();
1363
1364 if window.key_matchers.get(&global_id).is_none() {
1365 window.key_matchers.insert(
1366 global_id.clone(),
1367 window
1368 .prev_frame_key_matchers
1369 .remove(&global_id)
1370 .unwrap_or_else(|| KeyMatcher::new(keymap)),
1371 );
1372 }
1373
1374 let result = f(global_id, self);
1375 let window: &mut Window = self.borrow_mut();
1376 window.element_id_stack.pop();
1377 result
1378 }
1379
1380 /// Invoke the given function with the given content mask after intersecting it
1381 /// with the current mask.
1382 fn with_content_mask<R>(
1383 &mut self,
1384 mask: ContentMask<Pixels>,
1385 f: impl FnOnce(&mut Self) -> R,
1386 ) -> R {
1387 let mask = mask.intersect(&self.content_mask());
1388 self.window_mut().content_mask_stack.push(mask);
1389 let result = f(self);
1390 self.window_mut().content_mask_stack.pop();
1391 result
1392 }
1393
1394 /// Update the global element offset based on the given offset. This is used to implement
1395 /// scrolling and position drag handles.
1396 fn with_element_offset<R>(
1397 &mut self,
1398 offset: Option<Point<Pixels>>,
1399 f: impl FnOnce(&mut Self) -> R,
1400 ) -> R {
1401 let Some(offset) = offset else {
1402 return f(self);
1403 };
1404
1405 let offset = self.element_offset() + offset;
1406 self.window_mut().element_offset_stack.push(offset);
1407 let result = f(self);
1408 self.window_mut().element_offset_stack.pop();
1409 result
1410 }
1411
1412 /// Obtain the current element offset.
1413 fn element_offset(&self) -> Point<Pixels> {
1414 self.window()
1415 .element_offset_stack
1416 .last()
1417 .copied()
1418 .unwrap_or_default()
1419 }
1420
1421 /// Update or intialize state for an element with the given id that lives across multiple
1422 /// frames. If an element with this id existed in the previous frame, its state will be passed
1423 /// to the given closure. The state returned by the closure will be stored so it can be referenced
1424 /// when drawing the next frame.
1425 fn with_element_state<S, R>(
1426 &mut self,
1427 id: ElementId,
1428 f: impl FnOnce(Option<S>, &mut Self) -> (R, S),
1429 ) -> R
1430 where
1431 S: 'static + Send,
1432 {
1433 self.with_element_id(id, |global_id, cx| {
1434 if let Some(any) = cx
1435 .window_mut()
1436 .element_states
1437 .remove(&global_id)
1438 .or_else(|| cx.window_mut().prev_frame_element_states.remove(&global_id))
1439 {
1440 // Using the extra inner option to avoid needing to reallocate a new box.
1441 let mut state_box = any
1442 .downcast::<Option<S>>()
1443 .expect("invalid element state type for id");
1444 let state = state_box
1445 .take()
1446 .expect("element state is already on the stack");
1447 let (result, state) = f(Some(state), cx);
1448 state_box.replace(state);
1449 cx.window_mut().element_states.insert(global_id, state_box);
1450 result
1451 } else {
1452 let (result, state) = f(None, cx);
1453 cx.window_mut()
1454 .element_states
1455 .insert(global_id, Box::new(Some(state)));
1456 result
1457 }
1458 })
1459 }
1460
1461 /// Like `with_element_state`, but for situations where the element_id is optional. If the
1462 /// id is `None`, no state will be retrieved or stored.
1463 fn with_optional_element_state<S, R>(
1464 &mut self,
1465 element_id: Option<ElementId>,
1466 f: impl FnOnce(Option<S>, &mut Self) -> (R, S),
1467 ) -> R
1468 where
1469 S: 'static + Send,
1470 {
1471 if let Some(element_id) = element_id {
1472 self.with_element_state(element_id, f)
1473 } else {
1474 f(None, self).0
1475 }
1476 }
1477
1478 /// Obtain the current content mask.
1479 fn content_mask(&self) -> ContentMask<Pixels> {
1480 self.window()
1481 .content_mask_stack
1482 .last()
1483 .cloned()
1484 .unwrap_or_else(|| ContentMask {
1485 bounds: Bounds {
1486 origin: Point::default(),
1487 size: self.window().content_size,
1488 },
1489 })
1490 }
1491
1492 /// The size of an em for the base font of the application. Adjusting this value allows the
1493 /// UI to scale, just like zooming a web page.
1494 fn rem_size(&self) -> Pixels {
1495 self.window().rem_size
1496 }
1497}
1498
1499impl Borrow<Window> for WindowContext<'_, '_> {
1500 fn borrow(&self) -> &Window {
1501 &self.window
1502 }
1503}
1504
1505impl BorrowMut<Window> for WindowContext<'_, '_> {
1506 fn borrow_mut(&mut self) -> &mut Window {
1507 &mut self.window
1508 }
1509}
1510
1511impl<T> BorrowWindow for T where T: BorrowMut<AppContext> + BorrowMut<Window> {}
1512
1513pub struct ViewContext<'a, 'w, V> {
1514 window_cx: WindowContext<'a, 'w>,
1515 view: WeakView<V>,
1516}
1517
1518impl<V> Borrow<AppContext> for ViewContext<'_, '_, V> {
1519 fn borrow(&self) -> &AppContext {
1520 &*self.window_cx.app
1521 }
1522}
1523
1524impl<V> BorrowMut<AppContext> for ViewContext<'_, '_, V> {
1525 fn borrow_mut(&mut self) -> &mut AppContext {
1526 &mut *self.window_cx.app
1527 }
1528}
1529
1530impl<V> Borrow<Window> for ViewContext<'_, '_, V> {
1531 fn borrow(&self) -> &Window {
1532 &*self.window_cx.window
1533 }
1534}
1535
1536impl<V> BorrowMut<Window> for ViewContext<'_, '_, V> {
1537 fn borrow_mut(&mut self) -> &mut Window {
1538 &mut *self.window_cx.window
1539 }
1540}
1541
1542impl<'a, 'w, V: 'static> ViewContext<'a, 'w, V> {
1543 pub(crate) fn mutable(
1544 app: &'a mut AppContext,
1545 window: &'w mut Window,
1546 view: WeakView<V>,
1547 ) -> Self {
1548 Self {
1549 window_cx: WindowContext::mutable(app, window),
1550 view,
1551 }
1552 }
1553
1554 pub fn view(&self) -> WeakView<V> {
1555 self.view.clone()
1556 }
1557
1558 pub fn model(&self) -> WeakModel<V> {
1559 self.view.model.clone()
1560 }
1561
1562 pub fn stack<R>(&mut self, order: u32, f: impl FnOnce(&mut Self) -> R) -> R {
1563 self.window.z_index_stack.push(order);
1564 let result = f(self);
1565 self.window.z_index_stack.pop();
1566 result
1567 }
1568
1569 pub fn on_next_frame(&mut self, f: impl FnOnce(&mut V, &mut ViewContext<V>) + Send + 'static)
1570 where
1571 V: Any + Send,
1572 {
1573 let view = self.view().upgrade().unwrap();
1574 self.window_cx.on_next_frame(move |cx| view.update(cx, f));
1575 }
1576
1577 pub fn observe<V2, E>(
1578 &mut self,
1579 entity: &E,
1580 mut on_notify: impl FnMut(&mut V, E, &mut ViewContext<'_, '_, V>) + Send + 'static,
1581 ) -> Subscription
1582 where
1583 V2: 'static,
1584 V: Any + Send,
1585 E: Entity<V2>,
1586 {
1587 let view = self.view();
1588 let entity_id = entity.entity_id();
1589 let entity = entity.downgrade();
1590 let window_handle = self.window.handle;
1591 self.app.observers.insert(
1592 entity_id,
1593 Box::new(move |cx| {
1594 cx.update_window(window_handle.id, |cx| {
1595 if let Some(handle) = E::upgrade_from(&entity) {
1596 view.update(cx, |this, cx| on_notify(this, handle, cx))
1597 .is_ok()
1598 } else {
1599 false
1600 }
1601 })
1602 .unwrap_or(false)
1603 }),
1604 )
1605 }
1606
1607 pub fn subscribe<V2, E>(
1608 &mut self,
1609 entity: &E,
1610 mut on_event: impl FnMut(&mut V, E, &V2::Event, &mut ViewContext<'_, '_, V>) + Send + 'static,
1611 ) -> Subscription
1612 where
1613 V2: EventEmitter,
1614 E: Entity<V2>,
1615 {
1616 let view = self.view();
1617 let entity_id = entity.entity_id();
1618 let handle = entity.downgrade();
1619 let window_handle = self.window.handle;
1620 self.app.event_listeners.insert(
1621 entity_id,
1622 Box::new(move |event, cx| {
1623 cx.update_window(window_handle.id, |cx| {
1624 if let Some(handle) = E::upgrade_from(&handle) {
1625 let event = event.downcast_ref().expect("invalid event type");
1626 view.update(cx, |this, cx| on_event(this, handle, event, cx))
1627 .is_ok()
1628 } else {
1629 false
1630 }
1631 })
1632 .unwrap_or(false)
1633 }),
1634 )
1635 }
1636
1637 pub fn on_release(
1638 &mut self,
1639 mut on_release: impl FnMut(&mut V, &mut WindowContext) + Send + 'static,
1640 ) -> Subscription {
1641 let window_handle = self.window.handle;
1642 self.app.release_listeners.insert(
1643 self.view.model.entity_id,
1644 Box::new(move |this, cx| {
1645 let this = this.downcast_mut().expect("invalid entity type");
1646 // todo!("are we okay with silently swallowing the error?")
1647 let _ = cx.update_window(window_handle.id, |cx| on_release(this, cx));
1648 }),
1649 )
1650 }
1651
1652 pub fn observe_release<V2, E>(
1653 &mut self,
1654 entity: &E,
1655 mut on_release: impl FnMut(&mut V, &mut V2, &mut ViewContext<'_, '_, V>) + Send + 'static,
1656 ) -> Subscription
1657 where
1658 V: Any + Send,
1659 V2: 'static,
1660 E: Entity<V2>,
1661 {
1662 let view = self.view();
1663 let entity_id = entity.entity_id();
1664 let window_handle = self.window.handle;
1665 self.app.release_listeners.insert(
1666 entity_id,
1667 Box::new(move |entity, cx| {
1668 let entity = entity.downcast_mut().expect("invalid entity type");
1669 let _ = cx.update_window(window_handle.id, |cx| {
1670 view.update(cx, |this, cx| on_release(this, entity, cx))
1671 });
1672 }),
1673 )
1674 }
1675
1676 pub fn notify(&mut self) {
1677 self.window_cx.notify();
1678 self.window_cx.app.push_effect(Effect::Notify {
1679 emitter: self.view.model.entity_id,
1680 });
1681 }
1682
1683 pub fn on_focus_changed(
1684 &mut self,
1685 listener: impl Fn(&mut V, &FocusEvent, &mut ViewContext<V>) + Send + 'static,
1686 ) {
1687 let handle = self.view();
1688 self.window.focus_listeners.push(Box::new(move |event, cx| {
1689 handle
1690 .update(cx, |view, cx| listener(view, event, cx))
1691 .log_err();
1692 }));
1693 }
1694
1695 pub fn with_key_listeners<R>(
1696 &mut self,
1697 key_listeners: impl IntoIterator<Item = (TypeId, KeyListener<V>)>,
1698 f: impl FnOnce(&mut Self) -> R,
1699 ) -> R {
1700 let old_stack_len = self.window.key_dispatch_stack.len();
1701 if !self.window.freeze_key_dispatch_stack {
1702 for (event_type, listener) in key_listeners {
1703 let handle = self.view();
1704 let listener = Box::new(
1705 move |event: &dyn Any,
1706 context_stack: &[&DispatchContext],
1707 phase: DispatchPhase,
1708 cx: &mut WindowContext<'_, '_>| {
1709 handle
1710 .update(cx, |view, cx| {
1711 listener(view, event, context_stack, phase, cx)
1712 })
1713 .log_err()
1714 .flatten()
1715 },
1716 );
1717 self.window
1718 .key_dispatch_stack
1719 .push(KeyDispatchStackFrame::Listener {
1720 event_type,
1721 listener,
1722 });
1723 }
1724 }
1725
1726 let result = f(self);
1727
1728 if !self.window.freeze_key_dispatch_stack {
1729 self.window.key_dispatch_stack.truncate(old_stack_len);
1730 }
1731
1732 result
1733 }
1734
1735 pub fn with_key_dispatch_context<R>(
1736 &mut self,
1737 context: DispatchContext,
1738 f: impl FnOnce(&mut Self) -> R,
1739 ) -> R {
1740 if context.is_empty() {
1741 return f(self);
1742 }
1743
1744 if !self.window.freeze_key_dispatch_stack {
1745 self.window
1746 .key_dispatch_stack
1747 .push(KeyDispatchStackFrame::Context(context));
1748 }
1749
1750 let result = f(self);
1751
1752 if !self.window.freeze_key_dispatch_stack {
1753 self.window.key_dispatch_stack.pop();
1754 }
1755
1756 result
1757 }
1758
1759 pub fn with_focus<R>(
1760 &mut self,
1761 focus_handle: FocusHandle,
1762 f: impl FnOnce(&mut Self) -> R,
1763 ) -> R {
1764 if let Some(parent_focus_id) = self.window.focus_stack.last().copied() {
1765 self.window
1766 .focus_parents_by_child
1767 .insert(focus_handle.id, parent_focus_id);
1768 }
1769 self.window.focus_stack.push(focus_handle.id);
1770
1771 if Some(focus_handle.id) == self.window.focus {
1772 self.window.freeze_key_dispatch_stack = true;
1773 }
1774
1775 let result = f(self);
1776
1777 self.window.focus_stack.pop();
1778 result
1779 }
1780
1781 pub fn run_on_main<R>(
1782 &mut self,
1783 view: &mut V,
1784 f: impl FnOnce(&mut V, &mut MainThread<ViewContext<'_, '_, V>>) -> R + Send + 'static,
1785 ) -> Task<Result<R>>
1786 where
1787 R: Send + 'static,
1788 {
1789 if self.executor.is_main_thread() {
1790 let cx = unsafe { mem::transmute::<&mut Self, &mut MainThread<Self>>(self) };
1791 Task::ready(Ok(f(view, cx)))
1792 } else {
1793 let view = self.view().upgrade().unwrap();
1794 self.window_cx.run_on_main(move |cx| view.update(cx, f))
1795 }
1796 }
1797
1798 pub fn spawn<Fut, R>(
1799 &mut self,
1800 f: impl FnOnce(WeakView<V>, AsyncWindowContext) -> Fut + Send + 'static,
1801 ) -> Task<R>
1802 where
1803 R: Send + 'static,
1804 Fut: Future<Output = R> + Send + 'static,
1805 {
1806 let view = self.view();
1807 self.window_cx.spawn(move |_, cx| {
1808 let result = f(view, cx);
1809 async move { result.await }
1810 })
1811 }
1812
1813 pub fn update_global<G, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R
1814 where
1815 G: 'static + Send,
1816 {
1817 let mut global = self.app.lease_global::<G>();
1818 let result = f(&mut global, self);
1819 self.app.end_global_lease(global);
1820 result
1821 }
1822
1823 pub fn observe_global<G: 'static>(
1824 &mut self,
1825 f: impl Fn(&mut V, &mut ViewContext<'_, '_, V>) + Send + 'static,
1826 ) -> Subscription {
1827 let window_id = self.window.handle.id;
1828 let handle = self.view();
1829 self.global_observers.insert(
1830 TypeId::of::<G>(),
1831 Box::new(move |cx| {
1832 cx.update_window(window_id, |cx| {
1833 handle.update(cx, |view, cx| f(view, cx)).is_ok()
1834 })
1835 .unwrap_or(false)
1836 }),
1837 )
1838 }
1839
1840 pub fn on_mouse_event<Event: 'static>(
1841 &mut self,
1842 handler: impl Fn(&mut V, &Event, DispatchPhase, &mut ViewContext<V>) + Send + 'static,
1843 ) {
1844 let handle = self.view().upgrade().unwrap();
1845 self.window_cx.on_mouse_event(move |event, phase, cx| {
1846 handle.update(cx, |view, cx| {
1847 handler(view, event, phase, cx);
1848 })
1849 });
1850 }
1851}
1852
1853impl<'a, 'w, V> ViewContext<'a, 'w, V>
1854where
1855 V: EventEmitter,
1856 V::Event: Any + Send,
1857{
1858 pub fn emit(&mut self, event: V::Event) {
1859 let emitter = self.view.model.entity_id;
1860 self.app.push_effect(Effect::Emit {
1861 emitter,
1862 event: Box::new(event),
1863 });
1864 }
1865}
1866
1867impl<'a, 'w, V> Context for ViewContext<'a, 'w, V> {
1868 type ModelContext<'b, U> = ModelContext<'b, U>;
1869 type Result<U> = U;
1870
1871 fn build_model<T>(
1872 &mut self,
1873 build_model: impl FnOnce(&mut Self::ModelContext<'_, T>) -> T,
1874 ) -> Model<T>
1875 where
1876 T: 'static + Send,
1877 {
1878 self.window_cx.build_model(build_model)
1879 }
1880
1881 fn update_model<T: 'static, R>(
1882 &mut self,
1883 model: &Model<T>,
1884 update: impl FnOnce(&mut T, &mut Self::ModelContext<'_, T>) -> R,
1885 ) -> R {
1886 self.window_cx.update_model(model, update)
1887 }
1888}
1889
1890impl<V: 'static> VisualContext for ViewContext<'_, '_, V> {
1891 type ViewContext<'a, 'w, V2> = ViewContext<'a, 'w, V2>;
1892
1893 fn build_view<W: 'static + Send>(
1894 &mut self,
1895 build_view: impl FnOnce(&mut Self::ViewContext<'_, '_, W>) -> W,
1896 ) -> Self::Result<View<W>> {
1897 self.window_cx.build_view(build_view)
1898 }
1899
1900 fn update_view<V2: 'static, R>(
1901 &mut self,
1902 view: &View<V2>,
1903 update: impl FnOnce(&mut V2, &mut Self::ViewContext<'_, '_, V2>) -> R,
1904 ) -> Self::Result<R> {
1905 self.window_cx.update_view(view, update)
1906 }
1907}
1908
1909impl<'a, 'w, V> std::ops::Deref for ViewContext<'a, 'w, V> {
1910 type Target = WindowContext<'a, 'w>;
1911
1912 fn deref(&self) -> &Self::Target {
1913 &self.window_cx
1914 }
1915}
1916
1917impl<'a, 'w, V> std::ops::DerefMut for ViewContext<'a, 'w, V> {
1918 fn deref_mut(&mut self) -> &mut Self::Target {
1919 &mut self.window_cx
1920 }
1921}
1922
1923// #[derive(Clone, Copy, Eq, PartialEq, Hash)]
1924slotmap::new_key_type! { pub struct WindowId; }
1925
1926impl WindowId {
1927 pub fn as_u64(&self) -> u64 {
1928 self.0.as_ffi()
1929 }
1930}
1931
1932#[derive(PartialEq, Eq)]
1933pub struct WindowHandle<V> {
1934 id: WindowId,
1935 state_type: PhantomData<V>,
1936}
1937
1938impl<S> Copy for WindowHandle<S> {}
1939
1940impl<S> Clone for WindowHandle<S> {
1941 fn clone(&self) -> Self {
1942 WindowHandle {
1943 id: self.id,
1944 state_type: PhantomData,
1945 }
1946 }
1947}
1948
1949impl<S> WindowHandle<S> {
1950 pub fn new(id: WindowId) -> Self {
1951 WindowHandle {
1952 id,
1953 state_type: PhantomData,
1954 }
1955 }
1956}
1957
1958impl<S: 'static> Into<AnyWindowHandle> for WindowHandle<S> {
1959 fn into(self) -> AnyWindowHandle {
1960 AnyWindowHandle {
1961 id: self.id,
1962 state_type: TypeId::of::<S>(),
1963 }
1964 }
1965}
1966
1967#[derive(Copy, Clone, PartialEq, Eq)]
1968pub struct AnyWindowHandle {
1969 pub(crate) id: WindowId,
1970 state_type: TypeId,
1971}
1972
1973impl AnyWindowHandle {
1974 pub fn window_id(&self) -> WindowId {
1975 self.id
1976 }
1977}
1978
1979#[cfg(any(test, feature = "test-support"))]
1980impl From<SmallVec<[u32; 16]>> for StackingOrder {
1981 fn from(small_vec: SmallVec<[u32; 16]>) -> Self {
1982 StackingOrder(small_vec)
1983 }
1984}
1985
1986#[derive(Clone, Debug, Eq, PartialEq, Hash)]
1987pub enum ElementId {
1988 View(EntityId),
1989 Number(usize),
1990 Name(SharedString),
1991 FocusHandle(FocusId),
1992}
1993
1994impl From<EntityId> for ElementId {
1995 fn from(id: EntityId) -> Self {
1996 ElementId::View(id)
1997 }
1998}
1999
2000impl From<usize> for ElementId {
2001 fn from(id: usize) -> Self {
2002 ElementId::Number(id)
2003 }
2004}
2005
2006impl From<i32> for ElementId {
2007 fn from(id: i32) -> Self {
2008 Self::Number(id as usize)
2009 }
2010}
2011
2012impl From<SharedString> for ElementId {
2013 fn from(name: SharedString) -> Self {
2014 ElementId::Name(name)
2015 }
2016}
2017
2018impl From<&'static str> for ElementId {
2019 fn from(name: &'static str) -> Self {
2020 ElementId::Name(name.into())
2021 }
2022}
2023
2024impl<'a> From<&'a FocusHandle> for ElementId {
2025 fn from(handle: &'a FocusHandle) -> Self {
2026 ElementId::FocusHandle(handle.id)
2027 }
2028}