1use crate::{
2 px, size, Action, AnyBox, AnyDrag, AnyView, AppContext, AsyncWindowContext, AvailableSpace,
3 Bounds, BoxShadow, Context, Corners, DevicePixels, DispatchContext, DisplayId, Edges, Effect,
4 EntityId, EventEmitter, ExternalPaths, FileDropEvent, FocusEvent, FontId, GlobalElementId,
5 GlyphId, Handle, Hsla, ImageData, InputEvent, IsZero, KeyListener, KeyMatch, KeyMatcher,
6 Keystroke, LayoutId, MainThread, MainThreadOnly, ModelContext, Modifiers, MonochromeSprite,
7 MouseButton, MouseDownEvent, MouseMoveEvent, MouseUpEvent, Path, Pixels, PlatformAtlas,
8 PlatformWindow, Point, PolychromeSprite, Quad, Reference, RenderGlyphParams, RenderImageParams,
9 RenderSvgParams, ScaledPixels, SceneBuilder, Shadow, SharedString, Size, Style, Subscription,
10 TaffyLayoutEngine, Task, Underline, UnderlineStyle, View, VisualContext, WeakHandle, 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 pub(crate) 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 self.window.focus = Some(handle.id);
358 self.app.push_effect(Effect::FocusChanged {
359 window_handle: self.window.handle,
360 focused: Some(handle.id),
361 });
362 self.notify();
363 }
364
365 /// Remove focus from all elements within this context's window.
366 pub fn blur(&mut self) {
367 if self.window.last_blur.is_none() {
368 self.window.last_blur = Some(self.window.focus);
369 }
370
371 self.window.focus = None;
372 self.app.push_effect(Effect::FocusChanged {
373 window_handle: self.window.handle,
374 focused: None,
375 });
376 self.notify();
377 }
378
379 /// Schedule the given closure to be run on the main thread. It will be invoked with
380 /// a `MainThread<WindowContext>`, which provides access to platform-specific functionality
381 /// of the window.
382 pub fn run_on_main<R>(
383 &mut self,
384 f: impl FnOnce(&mut MainThread<WindowContext<'_, '_>>) -> R + Send + 'static,
385 ) -> Task<Result<R>>
386 where
387 R: Send + 'static,
388 {
389 if self.executor.is_main_thread() {
390 Task::ready(Ok(f(unsafe {
391 mem::transmute::<&mut Self, &mut MainThread<Self>>(self)
392 })))
393 } else {
394 let handle = self.window.handle;
395 self.app.run_on_main(move |cx| cx.update_window(handle, f))
396 }
397 }
398
399 /// Create an `AsyncWindowContext`, which has a static lifetime and can be held across
400 /// await points in async code.
401 pub fn to_async(&self) -> AsyncWindowContext {
402 AsyncWindowContext::new(self.app.to_async(), self.window.handle)
403 }
404
405 /// Schedule the given closure to be run directly after the current frame is rendered.
406 pub fn on_next_frame(&mut self, f: impl FnOnce(&mut WindowContext) + Send + 'static) {
407 let f = Box::new(f);
408 let display_id = self.window.display_id;
409 self.run_on_main(move |cx| {
410 if let Some(callbacks) = cx.next_frame_callbacks.get_mut(&display_id) {
411 callbacks.push(f);
412 // If there was already a callback, it means that we already scheduled a frame.
413 if callbacks.len() > 1 {
414 return;
415 }
416 } else {
417 let async_cx = cx.to_async();
418 cx.next_frame_callbacks.insert(display_id, vec![f]);
419 cx.platform().set_display_link_output_callback(
420 display_id,
421 Box::new(move |_current_time, _output_time| {
422 let _ = async_cx.update(|cx| {
423 let callbacks = cx
424 .next_frame_callbacks
425 .get_mut(&display_id)
426 .unwrap()
427 .drain(..)
428 .collect::<Vec<_>>();
429 for callback in callbacks {
430 callback(cx);
431 }
432
433 cx.run_on_main(move |cx| {
434 if cx.next_frame_callbacks.get(&display_id).unwrap().is_empty() {
435 cx.platform().stop_display_link(display_id);
436 }
437 })
438 .detach();
439 });
440 }),
441 );
442 }
443
444 cx.platform().start_display_link(display_id);
445 })
446 .detach();
447 }
448
449 /// Spawn the future returned by the given closure on the application thread pool.
450 /// The closure is provided a handle to the current window and an `AsyncWindowContext` for
451 /// use within your future.
452 pub fn spawn<Fut, R>(
453 &mut self,
454 f: impl FnOnce(AnyWindowHandle, AsyncWindowContext) -> Fut + Send + 'static,
455 ) -> Task<R>
456 where
457 R: Send + 'static,
458 Fut: Future<Output = R> + Send + 'static,
459 {
460 let window = self.window.handle;
461 self.app.spawn(move |app| {
462 let cx = AsyncWindowContext::new(app, window);
463 let future = f(window, cx);
464 async move { future.await }
465 })
466 }
467
468 /// Update the global of the given type. The given closure is given simultaneous mutable
469 /// access both to the global and the context.
470 pub fn update_global<G, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R
471 where
472 G: 'static,
473 {
474 let mut global = self.app.lease_global::<G>();
475 let result = f(&mut global, self);
476 self.app.end_global_lease(global);
477 result
478 }
479
480 /// Add a node to the layout tree for the current frame. Takes the `Style` of the element for which
481 /// layout is being requested, along with the layout ids of any children. This method is called during
482 /// calls to the `Element::layout` trait method and enables any element to participate in layout.
483 pub fn request_layout(
484 &mut self,
485 style: &Style,
486 children: impl IntoIterator<Item = LayoutId>,
487 ) -> LayoutId {
488 self.app.layout_id_buffer.clear();
489 self.app.layout_id_buffer.extend(children.into_iter());
490 let rem_size = self.rem_size();
491
492 self.window
493 .layout_engine
494 .request_layout(style, rem_size, &self.app.layout_id_buffer)
495 }
496
497 /// Add a node to the layout tree for the current frame. Instead of taking a `Style` and children,
498 /// this variant takes a function that is invoked during layout so you can use arbitrary logic to
499 /// determine the element's size. One place this is used internally is when measuring text.
500 ///
501 /// The given closure is invoked at layout time with the known dimensions and available space and
502 /// returns a `Size`.
503 pub fn request_measured_layout<
504 F: Fn(Size<Option<Pixels>>, Size<AvailableSpace>) -> Size<Pixels> + Send + Sync + 'static,
505 >(
506 &mut self,
507 style: Style,
508 rem_size: Pixels,
509 measure: F,
510 ) -> LayoutId {
511 self.window
512 .layout_engine
513 .request_measured_layout(style, rem_size, measure)
514 }
515
516 /// Obtain the bounds computed for the given LayoutId relative to the window. This method should not
517 /// be invoked until the paint phase begins, and will usually be invoked by GPUI itself automatically
518 /// in order to pass your element its `Bounds` automatically.
519 pub fn layout_bounds(&mut self, layout_id: LayoutId) -> Bounds<Pixels> {
520 let mut bounds = self
521 .window
522 .layout_engine
523 .layout_bounds(layout_id)
524 .map(Into::into);
525 bounds.origin += self.element_offset();
526 bounds
527 }
528
529 /// The scale factor of the display associated with the window. For example, it could
530 /// return 2.0 for a "retina" display, indicating that each logical pixel should actually
531 /// be rendered as two pixels on screen.
532 pub fn scale_factor(&self) -> f32 {
533 self.window.scale_factor
534 }
535
536 /// The size of an em for the base font of the application. Adjusting this value allows the
537 /// UI to scale, just like zooming a web page.
538 pub fn rem_size(&self) -> Pixels {
539 self.window.rem_size
540 }
541
542 /// The line height associated with the current text style.
543 pub fn line_height(&self) -> Pixels {
544 let rem_size = self.rem_size();
545 let text_style = self.text_style();
546 text_style
547 .line_height
548 .to_pixels(text_style.font_size.into(), rem_size)
549 }
550
551 /// Call to prevent the default action of an event. Currently only used to prevent
552 /// parent elements from becoming focused on mouse down.
553 pub fn prevent_default(&mut self) {
554 self.window.default_prevented = true;
555 }
556
557 /// Obtain whether default has been prevented for the event currently being dispatched.
558 pub fn default_prevented(&self) -> bool {
559 self.window.default_prevented
560 }
561
562 /// Register a mouse event listener on the window for the current frame. The type of event
563 /// is determined by the first parameter of the given listener. When the next frame is rendered
564 /// the listener will be cleared.
565 ///
566 /// This is a fairly low-level method, so prefer using event handlers on elements unless you have
567 /// a specific need to register a global listener.
568 pub fn on_mouse_event<Event: 'static>(
569 &mut self,
570 handler: impl Fn(&Event, DispatchPhase, &mut WindowContext) + Send + 'static,
571 ) {
572 let order = self.window.z_index_stack.clone();
573 self.window
574 .mouse_listeners
575 .entry(TypeId::of::<Event>())
576 .or_default()
577 .push((
578 order,
579 Box::new(move |event: &dyn Any, phase, cx| {
580 handler(event.downcast_ref().unwrap(), phase, cx)
581 }),
582 ))
583 }
584
585 /// The position of the mouse relative to the window.
586 pub fn mouse_position(&self) -> Point<Pixels> {
587 self.window.mouse_position
588 }
589
590 /// Called during painting to invoke the given closure in a new stacking context. The given
591 /// z-index is interpreted relative to the previous call to `stack`.
592 pub fn stack<R>(&mut self, z_index: u32, f: impl FnOnce(&mut Self) -> R) -> R {
593 self.window.z_index_stack.push(z_index);
594 let result = f(self);
595 self.window.z_index_stack.pop();
596 result
597 }
598
599 /// Paint one or more drop shadows into the scene for the current frame at the current z-index.
600 pub fn paint_shadows(
601 &mut self,
602 bounds: Bounds<Pixels>,
603 corner_radii: Corners<Pixels>,
604 shadows: &[BoxShadow],
605 ) {
606 let scale_factor = self.scale_factor();
607 let content_mask = self.content_mask();
608 let window = &mut *self.window;
609 for shadow in shadows {
610 let mut shadow_bounds = bounds;
611 shadow_bounds.origin += shadow.offset;
612 shadow_bounds.dilate(shadow.spread_radius);
613 window.scene_builder.insert(
614 &window.z_index_stack,
615 Shadow {
616 order: 0,
617 bounds: shadow_bounds.scale(scale_factor),
618 content_mask: content_mask.scale(scale_factor),
619 corner_radii: corner_radii.scale(scale_factor),
620 color: shadow.color,
621 blur_radius: shadow.blur_radius.scale(scale_factor),
622 },
623 );
624 }
625 }
626
627 /// Paint one or more quads into the scene for the current frame at the current stacking context.
628 /// Quads are colored rectangular regions with an optional background, border, and corner radius.
629 pub fn paint_quad(
630 &mut self,
631 bounds: Bounds<Pixels>,
632 corner_radii: Corners<Pixels>,
633 background: impl Into<Hsla>,
634 border_widths: Edges<Pixels>,
635 border_color: impl Into<Hsla>,
636 ) {
637 let scale_factor = self.scale_factor();
638 let content_mask = self.content_mask();
639
640 let window = &mut *self.window;
641 window.scene_builder.insert(
642 &window.z_index_stack,
643 Quad {
644 order: 0,
645 bounds: bounds.scale(scale_factor),
646 content_mask: content_mask.scale(scale_factor),
647 background: background.into(),
648 border_color: border_color.into(),
649 corner_radii: corner_radii.scale(scale_factor),
650 border_widths: border_widths.scale(scale_factor),
651 },
652 );
653 }
654
655 /// Paint the given `Path` into the scene for the current frame at the current z-index.
656 pub fn paint_path(&mut self, mut path: Path<Pixels>, color: impl Into<Hsla>) {
657 let scale_factor = self.scale_factor();
658 let content_mask = self.content_mask();
659 path.content_mask = content_mask;
660 path.color = color.into();
661 let window = &mut *self.window;
662 window
663 .scene_builder
664 .insert(&window.z_index_stack, path.scale(scale_factor));
665 }
666
667 /// Paint an underline into the scene for the current frame at the current z-index.
668 pub fn paint_underline(
669 &mut self,
670 origin: Point<Pixels>,
671 width: Pixels,
672 style: &UnderlineStyle,
673 ) -> Result<()> {
674 let scale_factor = self.scale_factor();
675 let height = if style.wavy {
676 style.thickness * 3.
677 } else {
678 style.thickness
679 };
680 let bounds = Bounds {
681 origin,
682 size: size(width, height),
683 };
684 let content_mask = self.content_mask();
685 let window = &mut *self.window;
686 window.scene_builder.insert(
687 &window.z_index_stack,
688 Underline {
689 order: 0,
690 bounds: bounds.scale(scale_factor),
691 content_mask: content_mask.scale(scale_factor),
692 thickness: style.thickness.scale(scale_factor),
693 color: style.color.unwrap_or_default(),
694 wavy: style.wavy,
695 },
696 );
697 Ok(())
698 }
699
700 /// Paint a monochrome (non-emoji) glyph into the scene for the current frame at the current z-index.
701 pub fn paint_glyph(
702 &mut self,
703 origin: Point<Pixels>,
704 font_id: FontId,
705 glyph_id: GlyphId,
706 font_size: Pixels,
707 color: Hsla,
708 ) -> Result<()> {
709 let scale_factor = self.scale_factor();
710 let glyph_origin = origin.scale(scale_factor);
711 let subpixel_variant = Point {
712 x: (glyph_origin.x.0.fract() * SUBPIXEL_VARIANTS as f32).floor() as u8,
713 y: (glyph_origin.y.0.fract() * SUBPIXEL_VARIANTS as f32).floor() as u8,
714 };
715 let params = RenderGlyphParams {
716 font_id,
717 glyph_id,
718 font_size,
719 subpixel_variant,
720 scale_factor,
721 is_emoji: false,
722 };
723
724 let raster_bounds = self.text_system().raster_bounds(¶ms)?;
725 if !raster_bounds.is_zero() {
726 let tile =
727 self.window
728 .sprite_atlas
729 .get_or_insert_with(¶ms.clone().into(), &mut || {
730 let (size, bytes) = self.text_system().rasterize_glyph(¶ms)?;
731 Ok((size, Cow::Owned(bytes)))
732 })?;
733 let bounds = Bounds {
734 origin: glyph_origin.map(|px| px.floor()) + raster_bounds.origin.map(Into::into),
735 size: tile.bounds.size.map(Into::into),
736 };
737 let content_mask = self.content_mask().scale(scale_factor);
738 let window = &mut *self.window;
739 window.scene_builder.insert(
740 &window.z_index_stack,
741 MonochromeSprite {
742 order: 0,
743 bounds,
744 content_mask,
745 color,
746 tile,
747 },
748 );
749 }
750 Ok(())
751 }
752
753 /// Paint an emoji glyph into the scene for the current frame at the current z-index.
754 pub fn paint_emoji(
755 &mut self,
756 origin: Point<Pixels>,
757 font_id: FontId,
758 glyph_id: GlyphId,
759 font_size: Pixels,
760 ) -> Result<()> {
761 let scale_factor = self.scale_factor();
762 let glyph_origin = origin.scale(scale_factor);
763 let params = RenderGlyphParams {
764 font_id,
765 glyph_id,
766 font_size,
767 // We don't render emojis with subpixel variants.
768 subpixel_variant: Default::default(),
769 scale_factor,
770 is_emoji: true,
771 };
772
773 let raster_bounds = self.text_system().raster_bounds(¶ms)?;
774 if !raster_bounds.is_zero() {
775 let tile =
776 self.window
777 .sprite_atlas
778 .get_or_insert_with(¶ms.clone().into(), &mut || {
779 let (size, bytes) = self.text_system().rasterize_glyph(¶ms)?;
780 Ok((size, Cow::Owned(bytes)))
781 })?;
782 let bounds = Bounds {
783 origin: glyph_origin.map(|px| px.floor()) + raster_bounds.origin.map(Into::into),
784 size: tile.bounds.size.map(Into::into),
785 };
786 let content_mask = self.content_mask().scale(scale_factor);
787 let window = &mut *self.window;
788
789 window.scene_builder.insert(
790 &window.z_index_stack,
791 PolychromeSprite {
792 order: 0,
793 bounds,
794 corner_radii: Default::default(),
795 content_mask,
796 tile,
797 grayscale: false,
798 },
799 );
800 }
801 Ok(())
802 }
803
804 /// Paint a monochrome SVG into the scene for the current frame at the current stacking context.
805 pub fn paint_svg(
806 &mut self,
807 bounds: Bounds<Pixels>,
808 path: SharedString,
809 color: Hsla,
810 ) -> Result<()> {
811 let scale_factor = self.scale_factor();
812 let bounds = bounds.scale(scale_factor);
813 // Render the SVG at twice the size to get a higher quality result.
814 let params = RenderSvgParams {
815 path,
816 size: bounds
817 .size
818 .map(|pixels| DevicePixels::from((pixels.0 * 2.).ceil() as i32)),
819 };
820
821 let tile =
822 self.window
823 .sprite_atlas
824 .get_or_insert_with(¶ms.clone().into(), &mut || {
825 let bytes = self.svg_renderer.render(¶ms)?;
826 Ok((params.size, Cow::Owned(bytes)))
827 })?;
828 let content_mask = self.content_mask().scale(scale_factor);
829
830 let window = &mut *self.window;
831 window.scene_builder.insert(
832 &window.z_index_stack,
833 MonochromeSprite {
834 order: 0,
835 bounds,
836 content_mask,
837 color,
838 tile,
839 },
840 );
841
842 Ok(())
843 }
844
845 /// Paint an image into the scene for the current frame at the current z-index.
846 pub fn paint_image(
847 &mut self,
848 bounds: Bounds<Pixels>,
849 corner_radii: Corners<Pixels>,
850 data: Arc<ImageData>,
851 grayscale: bool,
852 ) -> Result<()> {
853 let scale_factor = self.scale_factor();
854 let bounds = bounds.scale(scale_factor);
855 let params = RenderImageParams { image_id: data.id };
856
857 let tile = self
858 .window
859 .sprite_atlas
860 .get_or_insert_with(¶ms.clone().into(), &mut || {
861 Ok((data.size(), Cow::Borrowed(data.as_bytes())))
862 })?;
863 let content_mask = self.content_mask().scale(scale_factor);
864 let corner_radii = corner_radii.scale(scale_factor);
865
866 let window = &mut *self.window;
867 window.scene_builder.insert(
868 &window.z_index_stack,
869 PolychromeSprite {
870 order: 0,
871 bounds,
872 content_mask,
873 corner_radii,
874 tile,
875 grayscale,
876 },
877 );
878 Ok(())
879 }
880
881 /// Draw pixels to the display for this window based on the contents of its scene.
882 pub(crate) fn draw(&mut self) {
883 let root_view = self.window.root_view.take().unwrap();
884
885 self.start_frame();
886
887 self.stack(0, |cx| {
888 let available_space = cx.window.content_size.map(Into::into);
889 root_view.draw(available_space, cx);
890 });
891
892 if let Some(mut active_drag) = self.app.active_drag.take() {
893 self.stack(1, |cx| {
894 let offset = cx.mouse_position() - active_drag.cursor_offset;
895 cx.with_element_offset(Some(offset), |cx| {
896 let available_space =
897 size(AvailableSpace::MinContent, AvailableSpace::MinContent);
898 if let Some(drag_handle_view) = &mut active_drag.drag_handle_view {
899 drag_handle_view.draw(available_space, cx);
900 }
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 self.active_drag.get_or_insert_with(|| AnyDrag {
969 drag_handle_view: None,
970 cursor_offset: position,
971 state: Box::new(files),
972 state_type: TypeId::of::<ExternalPaths>(),
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_handle = self.window.handle;
1155 self.global_observers.insert(
1156 TypeId::of::<G>(),
1157 Box::new(move |cx| cx.update_window(window_handle, |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 EntityContext<'a, T> = ModelContext<'a, T>;
1242 type Result<T> = T;
1243
1244 fn entity<T>(
1245 &mut self,
1246 build_entity: impl FnOnce(&mut Self::EntityContext<'_, T>) -> T,
1247 ) -> Handle<T>
1248 where
1249 T: 'static + Send,
1250 {
1251 let slot = self.app.entities.reserve();
1252 let entity = build_entity(&mut ModelContext::mutable(&mut *self.app, slot.downgrade()));
1253 self.entities.insert(slot, entity)
1254 }
1255
1256 fn update_entity<T: 'static, R>(
1257 &mut self,
1258 handle: &Handle<T>,
1259 update: impl FnOnce(&mut T, &mut Self::EntityContext<'_, T>) -> R,
1260 ) -> R {
1261 let mut entity = self.entities.lease(handle);
1262 let result = update(
1263 &mut *entity,
1264 &mut ModelContext::mutable(&mut *self.app, handle.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 /// Builds a new view in the current window. The first argument is a function that builds
1275 /// an entity representing the view's state. It is invoked with a `ViewContext` that provides
1276 /// entity-specific access to the window and application state during construction. The second
1277 /// argument is a render function that returns a component based on the view's state.
1278 fn build_view<E, V>(
1279 &mut self,
1280 build_view_state: impl FnOnce(&mut Self::ViewContext<'_, '_, V>) -> V,
1281 render: impl Fn(&mut V, &mut ViewContext<'_, '_, V>) -> E + Send + 'static,
1282 ) -> Self::Result<View<V>>
1283 where
1284 E: crate::Component<V>,
1285 V: 'static + Send,
1286 {
1287 let slot = self.app.entities.reserve();
1288 let view = View::for_handle(slot.clone(), render);
1289 let mut cx = ViewContext::mutable(&mut *self.app, &mut *self.window, view.downgrade());
1290 let entity = build_view_state(&mut cx);
1291 self.entities.insert(slot, entity);
1292 view
1293 }
1294
1295 /// Update the given view. Prefer calling `View::update` instead, which calls this method.
1296 fn update_view<T: 'static, R>(
1297 &mut self,
1298 view: &View<T>,
1299 update: impl FnOnce(&mut T, &mut Self::ViewContext<'_, '_, T>) -> R,
1300 ) -> Self::Result<R> {
1301 let mut lease = self.app.entities.lease(&view.state);
1302 let mut cx = ViewContext::mutable(&mut *self.app, &mut *self.window, view.downgrade());
1303 let result = update(&mut *lease, &mut cx);
1304 cx.app.entities.end_lease(lease);
1305 result
1306 }
1307}
1308
1309impl<'a, 'w> std::ops::Deref for WindowContext<'a, 'w> {
1310 type Target = AppContext;
1311
1312 fn deref(&self) -> &Self::Target {
1313 &self.app
1314 }
1315}
1316
1317impl<'a, 'w> std::ops::DerefMut for WindowContext<'a, 'w> {
1318 fn deref_mut(&mut self) -> &mut Self::Target {
1319 &mut self.app
1320 }
1321}
1322
1323impl<'a, 'w> Borrow<AppContext> for WindowContext<'a, 'w> {
1324 fn borrow(&self) -> &AppContext {
1325 &self.app
1326 }
1327}
1328
1329impl<'a, 'w> BorrowMut<AppContext> for WindowContext<'a, 'w> {
1330 fn borrow_mut(&mut self) -> &mut AppContext {
1331 &mut self.app
1332 }
1333}
1334
1335pub trait BorrowWindow: BorrowMut<Window> + BorrowMut<AppContext> {
1336 fn app_mut(&mut self) -> &mut AppContext {
1337 self.borrow_mut()
1338 }
1339
1340 fn window(&self) -> &Window {
1341 self.borrow()
1342 }
1343
1344 fn window_mut(&mut self) -> &mut Window {
1345 self.borrow_mut()
1346 }
1347
1348 /// Pushes the given element id onto the global stack and invokes the given closure
1349 /// with a `GlobalElementId`, which disambiguates the given id in the context of its ancestor
1350 /// ids. Because elements are discarded and recreated on each frame, the `GlobalElementId` is
1351 /// used to associate state with identified elements across separate frames.
1352 fn with_element_id<R>(
1353 &mut self,
1354 id: impl Into<ElementId>,
1355 f: impl FnOnce(GlobalElementId, &mut Self) -> R,
1356 ) -> R {
1357 let keymap = self.app_mut().keymap.clone();
1358 let window = self.window_mut();
1359 window.element_id_stack.push(id.into());
1360 let global_id = window.element_id_stack.clone();
1361
1362 if window.key_matchers.get(&global_id).is_none() {
1363 window.key_matchers.insert(
1364 global_id.clone(),
1365 window
1366 .prev_frame_key_matchers
1367 .remove(&global_id)
1368 .unwrap_or_else(|| KeyMatcher::new(keymap)),
1369 );
1370 }
1371
1372 let result = f(global_id, self);
1373 let window: &mut Window = self.borrow_mut();
1374 window.element_id_stack.pop();
1375 result
1376 }
1377
1378 /// Invoke the given function with the given content mask after intersecting it
1379 /// with the current mask.
1380 fn with_content_mask<R>(
1381 &mut self,
1382 mask: ContentMask<Pixels>,
1383 f: impl FnOnce(&mut Self) -> R,
1384 ) -> R {
1385 let mask = mask.intersect(&self.content_mask());
1386 self.window_mut().content_mask_stack.push(mask);
1387 let result = f(self);
1388 self.window_mut().content_mask_stack.pop();
1389 result
1390 }
1391
1392 /// Update the global element offset based on the given offset. This is used to implement
1393 /// scrolling and position drag handles.
1394 fn with_element_offset<R>(
1395 &mut self,
1396 offset: Option<Point<Pixels>>,
1397 f: impl FnOnce(&mut Self) -> R,
1398 ) -> R {
1399 let Some(offset) = offset else {
1400 return f(self);
1401 };
1402
1403 let offset = self.element_offset() + offset;
1404 self.window_mut().element_offset_stack.push(offset);
1405 let result = f(self);
1406 self.window_mut().element_offset_stack.pop();
1407 result
1408 }
1409
1410 /// Obtain the current element offset.
1411 fn element_offset(&self) -> Point<Pixels> {
1412 self.window()
1413 .element_offset_stack
1414 .last()
1415 .copied()
1416 .unwrap_or_default()
1417 }
1418
1419 /// Update or intialize state for an element with the given id that lives across multiple
1420 /// frames. If an element with this id existed in the previous frame, its state will be passed
1421 /// to the given closure. The state returned by the closure will be stored so it can be referenced
1422 /// when drawing the next frame.
1423 fn with_element_state<S, R>(
1424 &mut self,
1425 id: ElementId,
1426 f: impl FnOnce(Option<S>, &mut Self) -> (R, S),
1427 ) -> R
1428 where
1429 S: 'static + Send,
1430 {
1431 self.with_element_id(id, |global_id, cx| {
1432 if let Some(any) = cx
1433 .window_mut()
1434 .element_states
1435 .remove(&global_id)
1436 .or_else(|| cx.window_mut().prev_frame_element_states.remove(&global_id))
1437 {
1438 // Using the extra inner option to avoid needing to reallocate a new box.
1439 let mut state_box = any
1440 .downcast::<Option<S>>()
1441 .expect("invalid element state type for id");
1442 let state = state_box
1443 .take()
1444 .expect("element state is already on the stack");
1445 let (result, state) = f(Some(state), cx);
1446 state_box.replace(state);
1447 cx.window_mut().element_states.insert(global_id, state_box);
1448 result
1449 } else {
1450 let (result, state) = f(None, cx);
1451 cx.window_mut()
1452 .element_states
1453 .insert(global_id, Box::new(Some(state)));
1454 result
1455 }
1456 })
1457 }
1458
1459 /// Like `with_element_state`, but for situations where the element_id is optional. If the
1460 /// id is `None`, no state will be retrieved or stored.
1461 fn with_optional_element_state<S, R>(
1462 &mut self,
1463 element_id: Option<ElementId>,
1464 f: impl FnOnce(Option<S>, &mut Self) -> (R, S),
1465 ) -> R
1466 where
1467 S: 'static + Send,
1468 {
1469 if let Some(element_id) = element_id {
1470 self.with_element_state(element_id, f)
1471 } else {
1472 f(None, self).0
1473 }
1474 }
1475
1476 /// Obtain the current content mask.
1477 fn content_mask(&self) -> ContentMask<Pixels> {
1478 self.window()
1479 .content_mask_stack
1480 .last()
1481 .cloned()
1482 .unwrap_or_else(|| ContentMask {
1483 bounds: Bounds {
1484 origin: Point::default(),
1485 size: self.window().content_size,
1486 },
1487 })
1488 }
1489
1490 /// The size of an em for the base font of the application. Adjusting this value allows the
1491 /// UI to scale, just like zooming a web page.
1492 fn rem_size(&self) -> Pixels {
1493 self.window().rem_size
1494 }
1495}
1496
1497impl Borrow<Window> for WindowContext<'_, '_> {
1498 fn borrow(&self) -> &Window {
1499 &self.window
1500 }
1501}
1502
1503impl BorrowMut<Window> for WindowContext<'_, '_> {
1504 fn borrow_mut(&mut self) -> &mut Window {
1505 &mut self.window
1506 }
1507}
1508
1509impl<T> BorrowWindow for T where T: BorrowMut<AppContext> + BorrowMut<Window> {}
1510
1511pub struct ViewContext<'a, 'w, V> {
1512 window_cx: WindowContext<'a, 'w>,
1513 view: WeakView<V>,
1514}
1515
1516impl<V> Borrow<AppContext> for ViewContext<'_, '_, V> {
1517 fn borrow(&self) -> &AppContext {
1518 &*self.window_cx.app
1519 }
1520}
1521
1522impl<V> BorrowMut<AppContext> for ViewContext<'_, '_, V> {
1523 fn borrow_mut(&mut self) -> &mut AppContext {
1524 &mut *self.window_cx.app
1525 }
1526}
1527
1528impl<V> Borrow<Window> for ViewContext<'_, '_, V> {
1529 fn borrow(&self) -> &Window {
1530 &*self.window_cx.window
1531 }
1532}
1533
1534impl<V> BorrowMut<Window> for ViewContext<'_, '_, V> {
1535 fn borrow_mut(&mut self) -> &mut Window {
1536 &mut *self.window_cx.window
1537 }
1538}
1539
1540impl<'a, 'w, V: 'static> ViewContext<'a, 'w, V> {
1541 pub(crate) fn mutable(
1542 app: &'a mut AppContext,
1543 window: &'w mut Window,
1544 view: WeakView<V>,
1545 ) -> Self {
1546 Self {
1547 window_cx: WindowContext::mutable(app, window),
1548 view,
1549 }
1550 }
1551
1552 pub fn view(&self) -> WeakView<V> {
1553 self.view.clone()
1554 }
1555
1556 pub fn handle(&self) -> WeakHandle<V> {
1557 self.view.state.clone()
1558 }
1559
1560 pub fn stack<R>(&mut self, order: u32, f: impl FnOnce(&mut Self) -> R) -> R {
1561 self.window.z_index_stack.push(order);
1562 let result = f(self);
1563 self.window.z_index_stack.pop();
1564 result
1565 }
1566
1567 pub fn on_next_frame(&mut self, f: impl FnOnce(&mut V, &mut ViewContext<V>) + Send + 'static)
1568 where
1569 V: Any + Send,
1570 {
1571 let view = self.view().upgrade().unwrap();
1572 self.window_cx.on_next_frame(move |cx| view.update(cx, f));
1573 }
1574
1575 pub fn observe<E>(
1576 &mut self,
1577 handle: &Handle<E>,
1578 mut on_notify: impl FnMut(&mut V, Handle<E>, &mut ViewContext<'_, '_, V>) + Send + 'static,
1579 ) -> Subscription
1580 where
1581 E: 'static,
1582 V: Any + Send,
1583 {
1584 let view = self.view();
1585 let handle = handle.downgrade();
1586 let window_handle = self.window.handle;
1587 self.app.observers.insert(
1588 handle.entity_id,
1589 Box::new(move |cx| {
1590 cx.update_window(window_handle, |cx| {
1591 if let Some(handle) = handle.upgrade() {
1592 view.update(cx, |this, cx| on_notify(this, handle, cx))
1593 .is_ok()
1594 } else {
1595 false
1596 }
1597 })
1598 .unwrap_or(false)
1599 }),
1600 )
1601 }
1602
1603 pub fn subscribe<E: EventEmitter>(
1604 &mut self,
1605 handle: &Handle<E>,
1606 mut on_event: impl FnMut(&mut V, Handle<E>, &E::Event, &mut ViewContext<'_, '_, V>)
1607 + Send
1608 + 'static,
1609 ) -> Subscription {
1610 let view = self.view();
1611 let handle = handle.downgrade();
1612 let window_handle = self.window.handle;
1613 self.app.event_listeners.insert(
1614 handle.entity_id,
1615 Box::new(move |event, cx| {
1616 cx.update_window(window_handle, |cx| {
1617 if let Some(handle) = handle.upgrade() {
1618 let event = event.downcast_ref().expect("invalid event type");
1619 view.update(cx, |this, cx| on_event(this, handle, event, cx))
1620 .is_ok()
1621 } else {
1622 false
1623 }
1624 })
1625 .unwrap_or(false)
1626 }),
1627 )
1628 }
1629
1630 pub fn on_release(
1631 &mut self,
1632 mut on_release: impl FnMut(&mut V, &mut WindowContext) + Send + 'static,
1633 ) -> Subscription {
1634 let window_handle = self.window.handle;
1635 self.app.release_listeners.insert(
1636 self.view.state.entity_id,
1637 Box::new(move |this, cx| {
1638 let this = this.downcast_mut().expect("invalid entity type");
1639 // todo!("are we okay with silently swallowing the error?")
1640 let _ = cx.update_window(window_handle, |cx| on_release(this, cx));
1641 }),
1642 )
1643 }
1644
1645 pub fn observe_release<T: 'static>(
1646 &mut self,
1647 handle: &Handle<T>,
1648 mut on_release: impl FnMut(&mut V, &mut T, &mut ViewContext<'_, '_, V>) + Send + 'static,
1649 ) -> Subscription
1650 where
1651 V: Any + Send,
1652 {
1653 let view = self.view();
1654 let window_handle = self.window.handle;
1655 self.app.release_listeners.insert(
1656 handle.entity_id,
1657 Box::new(move |entity, cx| {
1658 let entity = entity.downcast_mut().expect("invalid entity type");
1659 let _ = cx.update_window(window_handle, |cx| {
1660 view.update(cx, |this, cx| on_release(this, entity, cx))
1661 });
1662 }),
1663 )
1664 }
1665
1666 pub fn notify(&mut self) {
1667 self.window_cx.notify();
1668 self.window_cx.app.push_effect(Effect::Notify {
1669 emitter: self.view.state.entity_id,
1670 });
1671 }
1672
1673 pub fn on_focus_changed(
1674 &mut self,
1675 listener: impl Fn(&mut V, &FocusEvent, &mut ViewContext<V>) + Send + 'static,
1676 ) {
1677 let handle = self.view();
1678 self.window.focus_listeners.push(Box::new(move |event, cx| {
1679 handle
1680 .update(cx, |view, cx| listener(view, event, cx))
1681 .log_err();
1682 }));
1683 }
1684
1685 pub fn with_key_listeners<R>(
1686 &mut self,
1687 key_listeners: impl IntoIterator<Item = (TypeId, KeyListener<V>)>,
1688 f: impl FnOnce(&mut Self) -> R,
1689 ) -> R {
1690 let old_stack_len = self.window.key_dispatch_stack.len();
1691 if !self.window.freeze_key_dispatch_stack {
1692 for (event_type, listener) in key_listeners {
1693 let handle = self.view();
1694 let listener = Box::new(
1695 move |event: &dyn Any,
1696 context_stack: &[&DispatchContext],
1697 phase: DispatchPhase,
1698 cx: &mut WindowContext<'_, '_>| {
1699 handle
1700 .update(cx, |view, cx| {
1701 listener(view, event, context_stack, phase, cx)
1702 })
1703 .log_err()
1704 .flatten()
1705 },
1706 );
1707 self.window
1708 .key_dispatch_stack
1709 .push(KeyDispatchStackFrame::Listener {
1710 event_type,
1711 listener,
1712 });
1713 }
1714 }
1715
1716 let result = f(self);
1717
1718 if !self.window.freeze_key_dispatch_stack {
1719 self.window.key_dispatch_stack.truncate(old_stack_len);
1720 }
1721
1722 result
1723 }
1724
1725 pub fn with_key_dispatch_context<R>(
1726 &mut self,
1727 context: DispatchContext,
1728 f: impl FnOnce(&mut Self) -> R,
1729 ) -> R {
1730 if context.is_empty() {
1731 return f(self);
1732 }
1733
1734 if !self.window.freeze_key_dispatch_stack {
1735 self.window
1736 .key_dispatch_stack
1737 .push(KeyDispatchStackFrame::Context(context));
1738 }
1739
1740 let result = f(self);
1741
1742 if !self.window.freeze_key_dispatch_stack {
1743 self.window.key_dispatch_stack.pop();
1744 }
1745
1746 result
1747 }
1748
1749 pub fn with_focus<R>(
1750 &mut self,
1751 focus_handle: FocusHandle,
1752 f: impl FnOnce(&mut Self) -> R,
1753 ) -> R {
1754 if let Some(parent_focus_id) = self.window.focus_stack.last().copied() {
1755 self.window
1756 .focus_parents_by_child
1757 .insert(focus_handle.id, parent_focus_id);
1758 }
1759 self.window.focus_stack.push(focus_handle.id);
1760
1761 if Some(focus_handle.id) == self.window.focus {
1762 self.window.freeze_key_dispatch_stack = true;
1763 }
1764
1765 let result = f(self);
1766
1767 self.window.focus_stack.pop();
1768 result
1769 }
1770
1771 pub fn run_on_main<R>(
1772 &mut self,
1773 view: &mut V,
1774 f: impl FnOnce(&mut V, &mut MainThread<ViewContext<'_, '_, V>>) -> R + Send + 'static,
1775 ) -> Task<Result<R>>
1776 where
1777 R: Send + 'static,
1778 {
1779 if self.executor.is_main_thread() {
1780 let cx = unsafe { mem::transmute::<&mut Self, &mut MainThread<Self>>(self) };
1781 Task::ready(Ok(f(view, cx)))
1782 } else {
1783 let view = self.view().upgrade().unwrap();
1784 self.window_cx.run_on_main(move |cx| view.update(cx, f))
1785 }
1786 }
1787
1788 pub fn spawn<Fut, R>(
1789 &mut self,
1790 f: impl FnOnce(WeakView<V>, AsyncWindowContext) -> Fut + Send + 'static,
1791 ) -> Task<R>
1792 where
1793 R: Send + 'static,
1794 Fut: Future<Output = R> + Send + 'static,
1795 {
1796 let view = self.view();
1797 self.window_cx.spawn(move |_, cx| {
1798 let result = f(view, cx);
1799 async move { result.await }
1800 })
1801 }
1802
1803 pub fn update_global<G, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R
1804 where
1805 G: 'static + Send,
1806 {
1807 let mut global = self.app.lease_global::<G>();
1808 let result = f(&mut global, self);
1809 self.app.end_global_lease(global);
1810 result
1811 }
1812
1813 pub fn observe_global<G: 'static>(
1814 &mut self,
1815 f: impl Fn(&mut V, &mut ViewContext<'_, '_, V>) + Send + 'static,
1816 ) -> Subscription {
1817 let window_handle = self.window.handle;
1818 let handle = self.view();
1819 self.global_observers.insert(
1820 TypeId::of::<G>(),
1821 Box::new(move |cx| {
1822 cx.update_window(window_handle, |cx| {
1823 handle.update(cx, |view, cx| f(view, cx)).is_ok()
1824 })
1825 .unwrap_or(false)
1826 }),
1827 )
1828 }
1829
1830 pub fn on_mouse_event<Event: 'static>(
1831 &mut self,
1832 handler: impl Fn(&mut V, &Event, DispatchPhase, &mut ViewContext<V>) + Send + 'static,
1833 ) {
1834 let handle = self.view().upgrade().unwrap();
1835 self.window_cx.on_mouse_event(move |event, phase, cx| {
1836 handle.update(cx, |view, cx| {
1837 handler(view, event, phase, cx);
1838 })
1839 });
1840 }
1841}
1842
1843impl<'a, 'w, V> ViewContext<'a, 'w, V>
1844where
1845 V: EventEmitter,
1846 V::Event: Any + Send,
1847{
1848 pub fn emit(&mut self, event: V::Event) {
1849 let emitter = self.view.state.entity_id;
1850 self.app.push_effect(Effect::Emit {
1851 emitter,
1852 event: Box::new(event),
1853 });
1854 }
1855}
1856
1857impl<'a, 'w, V: 'static> MainThread<ViewContext<'a, 'w, V>> {
1858 fn platform_window(&self) -> &dyn PlatformWindow {
1859 self.window.platform_window.borrow_on_main_thread().as_ref()
1860 }
1861
1862 pub fn activate_window(&self) {
1863 self.platform_window().activate();
1864 }
1865}
1866
1867impl<'a, 'w, V> Context for ViewContext<'a, 'w, V> {
1868 type EntityContext<'b, U> = ModelContext<'b, U>;
1869 type Result<U> = U;
1870
1871 fn entity<T>(
1872 &mut self,
1873 build_entity: impl FnOnce(&mut Self::EntityContext<'_, T>) -> T,
1874 ) -> Handle<T>
1875 where
1876 T: 'static + Send,
1877 {
1878 self.window_cx.entity(build_entity)
1879 }
1880
1881 fn update_entity<T: 'static, R>(
1882 &mut self,
1883 handle: &Handle<T>,
1884 update: impl FnOnce(&mut T, &mut Self::EntityContext<'_, T>) -> R,
1885 ) -> R {
1886 self.window_cx.update_entity(handle, 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<E, V2>(
1894 &mut self,
1895 build_entity: impl FnOnce(&mut Self::ViewContext<'_, '_, V2>) -> V2,
1896 render: impl Fn(&mut V2, &mut ViewContext<'_, '_, V2>) -> E + Send + 'static,
1897 ) -> Self::Result<View<V2>>
1898 where
1899 E: crate::Component<V2>,
1900 V2: 'static + Send,
1901 {
1902 self.window_cx.build_view(build_entity, render)
1903 }
1904
1905 fn update_view<V2: 'static, R>(
1906 &mut self,
1907 view: &View<V2>,
1908 update: impl FnOnce(&mut V2, &mut Self::ViewContext<'_, '_, V2>) -> R,
1909 ) -> Self::Result<R> {
1910 self.window_cx.update_view(view, update)
1911 }
1912}
1913
1914impl<'a, 'w, V> std::ops::Deref for ViewContext<'a, 'w, V> {
1915 type Target = WindowContext<'a, 'w>;
1916
1917 fn deref(&self) -> &Self::Target {
1918 &self.window_cx
1919 }
1920}
1921
1922impl<'a, 'w, V> std::ops::DerefMut for ViewContext<'a, 'w, V> {
1923 fn deref_mut(&mut self) -> &mut Self::Target {
1924 &mut self.window_cx
1925 }
1926}
1927
1928// #[derive(Clone, Copy, Eq, PartialEq, Hash)]
1929slotmap::new_key_type! { pub struct WindowId; }
1930
1931impl WindowId {
1932 pub fn as_u64(&self) -> u64 {
1933 self.0.as_ffi()
1934 }
1935}
1936
1937#[derive(PartialEq, Eq, Deref, DerefMut)]
1938pub struct WindowHandle<V> {
1939 #[deref]
1940 #[deref_mut]
1941 pub(crate) any_handle: AnyWindowHandle,
1942 state_type: PhantomData<V>,
1943}
1944
1945impl<V> Copy for WindowHandle<V> {}
1946
1947impl<V> Clone for WindowHandle<V> {
1948 fn clone(&self) -> Self {
1949 WindowHandle {
1950 any_handle: self.any_handle,
1951 state_type: PhantomData,
1952 }
1953 }
1954}
1955
1956impl<V: 'static> WindowHandle<V> {
1957 pub fn new(id: WindowId) -> Self {
1958 WindowHandle {
1959 any_handle: AnyWindowHandle {
1960 id,
1961 state_type: TypeId::of::<V>(),
1962 },
1963 state_type: PhantomData,
1964 }
1965 }
1966}
1967
1968impl<V: 'static> Into<AnyWindowHandle> for WindowHandle<V> {
1969 fn into(self) -> AnyWindowHandle {
1970 self.any_handle
1971 }
1972}
1973
1974#[derive(Copy, Clone, PartialEq, Eq)]
1975pub struct AnyWindowHandle {
1976 pub(crate) id: WindowId,
1977 state_type: TypeId,
1978}
1979
1980impl AnyWindowHandle {
1981 pub fn window_id(&self) -> WindowId {
1982 self.id
1983 }
1984
1985 pub fn downcast<T: 'static>(&self) -> Option<WindowHandle<T>> {
1986 if TypeId::of::<T>() == self.state_type {
1987 Some(WindowHandle {
1988 any_handle: *self,
1989 state_type: PhantomData,
1990 })
1991 } else {
1992 None
1993 }
1994 }
1995}
1996
1997#[cfg(any(test, feature = "test-support"))]
1998impl From<SmallVec<[u32; 16]>> for StackingOrder {
1999 fn from(small_vec: SmallVec<[u32; 16]>) -> Self {
2000 StackingOrder(small_vec)
2001 }
2002}
2003
2004#[derive(Clone, Debug, Eq, PartialEq, Hash)]
2005pub enum ElementId {
2006 View(EntityId),
2007 Number(usize),
2008 Name(SharedString),
2009 FocusHandle(FocusId),
2010}
2011
2012impl From<EntityId> for ElementId {
2013 fn from(id: EntityId) -> Self {
2014 ElementId::View(id)
2015 }
2016}
2017
2018impl From<usize> for ElementId {
2019 fn from(id: usize) -> Self {
2020 ElementId::Number(id)
2021 }
2022}
2023
2024impl From<i32> for ElementId {
2025 fn from(id: i32) -> Self {
2026 Self::Number(id as usize)
2027 }
2028}
2029
2030impl From<SharedString> for ElementId {
2031 fn from(name: SharedString) -> Self {
2032 ElementId::Name(name)
2033 }
2034}
2035
2036impl From<&'static str> for ElementId {
2037 fn from(name: &'static str) -> Self {
2038 ElementId::Name(name.into())
2039 }
2040}
2041
2042impl<'a> From<&'a FocusHandle> for ElementId {
2043 fn from(handle: &'a FocusHandle) -> Self {
2044 ElementId::FocusHandle(handle.id)
2045 }
2046}