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 Model, ModelContext, Modifiers, MonochromeSprite, MouseButton, MouseDownEvent, MouseMoveEvent,
7 MouseUpEvent, Path, Pixels, PlatformAtlas, PlatformWindow, Point, PolychromeSprite,
8 PromptLevel, Quad, Render, RenderGlyphParams, RenderImageParams, RenderSvgParams, ScaledPixels,
9 SceneBuilder, Shadow, SharedString, Size, Style, SubscriberSet, Subscription,
10 TaffyLayoutEngine, Task, Underline, UnderlineStyle, View, VisualContext, WeakView,
11 WindowOptions, SUBPIXEL_VARIANTS,
12};
13use anyhow::{anyhow, Result};
14use collections::HashMap;
15use derive_more::{Deref, DerefMut};
16use futures::channel::oneshot;
17use parking_lot::RwLock;
18use slotmap::SlotMap;
19use smallvec::SmallVec;
20use std::{
21 any::{Any, TypeId},
22 borrow::{Borrow, BorrowMut, Cow},
23 fmt::Debug,
24 future::Future,
25 hash::{Hash, Hasher},
26 marker::PhantomData,
27 mem,
28 sync::{
29 atomic::{AtomicUsize, Ordering::SeqCst},
30 Arc,
31 },
32};
33use util::ResultExt;
34
35/// A global stacking order, which is created by stacking successive z-index values.
36/// Each z-index will always be interpreted in the context of its parent z-index.
37#[derive(Deref, DerefMut, Ord, PartialOrd, Eq, PartialEq, Clone, Default)]
38pub(crate) struct StackingOrder(pub(crate) SmallVec<[u32; 16]>);
39
40/// Represents the two different phases when dispatching events.
41#[derive(Default, Copy, Clone, Debug, Eq, PartialEq)]
42pub enum DispatchPhase {
43 /// After the capture phase comes the bubble phase, in which mouse event listeners are
44 /// invoked front to back and keyboard event listeners are invoked from the focused element
45 /// to the root of the element tree. This is the phase you'll most commonly want to use when
46 /// registering event listeners.
47 #[default]
48 Bubble,
49 /// During the initial capture phase, mouse event listeners are invoked back to front, and keyboard
50 /// listeners are invoked from the root of the tree downward toward the focused element. This phase
51 /// is used for special purposes such as clearing the "pressed" state for click events. If
52 /// you stop event propagation during this phase, you need to know what you're doing. Handlers
53 /// outside of the immediate region may rely on detecting non-local events during this phase.
54 Capture,
55}
56
57type AnyListener = Box<dyn Fn(&dyn Any, DispatchPhase, &mut WindowContext) + 'static>;
58type AnyKeyListener = Box<
59 dyn Fn(
60 &dyn Any,
61 &[&DispatchContext],
62 DispatchPhase,
63 &mut WindowContext,
64 ) -> Option<Box<dyn Action>>
65 + 'static,
66>;
67type AnyFocusListener = Box<dyn Fn(&FocusEvent, &mut WindowContext) + 'static>;
68type AnyFullScreenListener = Box<dyn FnMut(bool, &mut WindowContext) -> bool + 'static>;
69
70slotmap::new_key_type! { pub struct FocusId; }
71
72/// A handle which can be used to track and manipulate the focused element in a window.
73pub struct FocusHandle {
74 pub(crate) id: FocusId,
75 handles: Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>,
76}
77
78impl FocusHandle {
79 pub(crate) fn new(handles: &Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>) -> Self {
80 let id = handles.write().insert(AtomicUsize::new(1));
81 Self {
82 id,
83 handles: handles.clone(),
84 }
85 }
86
87 pub(crate) fn for_id(
88 id: FocusId,
89 handles: &Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>,
90 ) -> Option<Self> {
91 let lock = handles.read();
92 let ref_count = lock.get(id)?;
93 if ref_count.load(SeqCst) == 0 {
94 None
95 } else {
96 ref_count.fetch_add(1, SeqCst);
97 Some(Self {
98 id,
99 handles: handles.clone(),
100 })
101 }
102 }
103
104 /// Obtains whether the element associated with this handle is currently focused.
105 pub fn is_focused(&self, cx: &WindowContext) -> bool {
106 cx.window.focus == Some(self.id)
107 }
108
109 /// Obtains whether the element associated with this handle contains the focused
110 /// element or is itself focused.
111 pub fn contains_focused(&self, cx: &WindowContext) -> bool {
112 cx.focused()
113 .map_or(false, |focused| self.contains(&focused, cx))
114 }
115
116 /// Obtains whether the element associated with this handle is contained within the
117 /// focused element or is itself focused.
118 pub fn within_focused(&self, cx: &WindowContext) -> bool {
119 let focused = cx.focused();
120 focused.map_or(false, |focused| focused.contains(self, cx))
121 }
122
123 /// Obtains whether this handle contains the given handle in the most recently rendered frame.
124 pub(crate) fn contains(&self, other: &Self, cx: &WindowContext) -> bool {
125 let mut ancestor = Some(other.id);
126 while let Some(ancestor_id) = ancestor {
127 if self.id == ancestor_id {
128 return true;
129 } else {
130 ancestor = cx.window.focus_parents_by_child.get(&ancestor_id).copied();
131 }
132 }
133 false
134 }
135}
136
137impl Clone for FocusHandle {
138 fn clone(&self) -> Self {
139 Self::for_id(self.id, &self.handles).unwrap()
140 }
141}
142
143impl PartialEq for FocusHandle {
144 fn eq(&self, other: &Self) -> bool {
145 self.id == other.id
146 }
147}
148
149impl Eq for FocusHandle {}
150
151impl Drop for FocusHandle {
152 fn drop(&mut self) {
153 self.handles
154 .read()
155 .get(self.id)
156 .unwrap()
157 .fetch_sub(1, SeqCst);
158 }
159}
160
161// Holds the state for a specific window.
162pub struct Window {
163 pub(crate) handle: AnyWindowHandle,
164 platform_window: Box<dyn PlatformWindow>,
165 display_id: DisplayId,
166 sprite_atlas: Arc<dyn PlatformAtlas>,
167 rem_size: Pixels,
168 content_size: Size<Pixels>,
169 pub(crate) layout_engine: TaffyLayoutEngine,
170 pub(crate) root_view: Option<AnyView>,
171 pub(crate) element_id_stack: GlobalElementId,
172 prev_frame_element_states: HashMap<GlobalElementId, AnyBox>,
173 element_states: HashMap<GlobalElementId, AnyBox>,
174 prev_frame_key_matchers: HashMap<GlobalElementId, KeyMatcher>,
175 key_matchers: HashMap<GlobalElementId, KeyMatcher>,
176 z_index_stack: StackingOrder,
177 content_mask_stack: Vec<ContentMask<Pixels>>,
178 element_offset_stack: Vec<Point<Pixels>>,
179 mouse_listeners: HashMap<TypeId, Vec<(StackingOrder, AnyListener)>>,
180 key_dispatch_stack: Vec<KeyDispatchStackFrame>,
181 freeze_key_dispatch_stack: bool,
182 focus_stack: Vec<FocusId>,
183 focus_parents_by_child: HashMap<FocusId, FocusId>,
184 pub(crate) focus_listeners: Vec<AnyFocusListener>,
185 fullscreen_listeners: SubscriberSet<(), AnyFullScreenListener>,
186 pub(crate) focus_handles: Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>,
187 default_prevented: bool,
188 mouse_position: Point<Pixels>,
189 scale_factor: f32,
190 fullscreen: bool,
191 pub(crate) scene_builder: SceneBuilder,
192 pub(crate) dirty: bool,
193 pub(crate) last_blur: Option<Option<FocusId>>,
194 pub(crate) focus: Option<FocusId>,
195}
196
197impl Window {
198 pub(crate) fn new(
199 handle: AnyWindowHandle,
200 options: WindowOptions,
201 cx: &mut AppContext,
202 ) -> Self {
203 let platform_window = cx.platform.open_window(handle, options);
204 let display_id = platform_window.display().id();
205 let sprite_atlas = platform_window.sprite_atlas();
206 let mouse_position = platform_window.mouse_position();
207 let content_size = platform_window.content_size();
208 let scale_factor = platform_window.scale_factor();
209
210 platform_window.on_resize(Box::new({
211 let mut cx = cx.to_async();
212 move |content_size, scale_factor| {
213 handle
214 .update(&mut cx, |_, cx| {
215 cx.window.scale_factor = scale_factor;
216 cx.window.scene_builder = SceneBuilder::new();
217 cx.window.content_size = content_size;
218 cx.window.display_id = cx.window.platform_window.display().id();
219 cx.window.dirty = true;
220 })
221 .log_err();
222 }
223 }));
224 platform_window.on_fullscreen(Box::new({
225 let mut cx = cx.to_async();
226 move |fullscreen| {
227 handle
228 .update(&mut cx, |_, cx| {
229 cx.window.fullscreen = fullscreen;
230 cx.window
231 .fullscreen_listeners
232 .clone()
233 .retain(&(), |callback| callback(fullscreen, cx));
234 cx.window.dirty = true;
235 })
236 .log_err();
237 }
238 }));
239
240 platform_window.on_input({
241 let mut cx = cx.to_async();
242 Box::new(move |event| {
243 handle
244 .update(&mut cx, |_, cx| cx.dispatch_event(event))
245 .log_err()
246 .unwrap_or(true)
247 })
248 });
249
250 Window {
251 handle,
252 platform_window,
253 display_id,
254 sprite_atlas,
255 rem_size: px(16.),
256 content_size,
257 layout_engine: TaffyLayoutEngine::new(),
258 root_view: None,
259 element_id_stack: GlobalElementId::default(),
260 prev_frame_element_states: HashMap::default(),
261 element_states: HashMap::default(),
262 prev_frame_key_matchers: HashMap::default(),
263 key_matchers: HashMap::default(),
264 z_index_stack: StackingOrder(SmallVec::new()),
265 content_mask_stack: Vec::new(),
266 element_offset_stack: Vec::new(),
267 mouse_listeners: HashMap::default(),
268 key_dispatch_stack: Vec::new(),
269 freeze_key_dispatch_stack: false,
270 focus_stack: Vec::new(),
271 focus_parents_by_child: HashMap::default(),
272 focus_listeners: Vec::new(),
273 fullscreen_listeners: SubscriberSet::new(),
274 focus_handles: Arc::new(RwLock::new(SlotMap::with_key())),
275 default_prevented: true,
276 mouse_position,
277 scale_factor,
278 fullscreen: false,
279 scene_builder: SceneBuilder::new(),
280 dirty: true,
281 last_blur: None,
282 focus: None,
283 }
284 }
285}
286
287/// When constructing the element tree, we maintain a stack of key dispatch frames until we
288/// find the focused element. We interleave key listeners with dispatch contexts so we can use the
289/// contexts when matching key events against the keymap.
290enum KeyDispatchStackFrame {
291 Listener {
292 event_type: TypeId,
293 listener: AnyKeyListener,
294 },
295 Context(DispatchContext),
296}
297
298/// Indicates which region of the window is visible. Content falling outside of this mask will not be
299/// rendered. Currently, only rectangular content masks are supported, but we give the mask its own type
300/// to leave room to support more complex shapes in the future.
301#[derive(Clone, Debug, Default, PartialEq, Eq)]
302#[repr(C)]
303pub struct ContentMask<P: Clone + Default + Debug> {
304 pub bounds: Bounds<P>,
305}
306
307impl ContentMask<Pixels> {
308 /// Scale the content mask's pixel units by the given scaling factor.
309 pub fn scale(&self, factor: f32) -> ContentMask<ScaledPixels> {
310 ContentMask {
311 bounds: self.bounds.scale(factor),
312 }
313 }
314
315 /// Intersect the content mask with the given content mask.
316 pub fn intersect(&self, other: &Self) -> Self {
317 let bounds = self.bounds.intersect(&other.bounds);
318 ContentMask { bounds }
319 }
320}
321
322/// Provides access to application state in the context of a single window. Derefs
323/// to an `AppContext`, so you can also pass a `WindowContext` to any method that takes
324/// an `AppContext` and call any `AppContext` methods.
325pub struct WindowContext<'a> {
326 pub(crate) app: &'a mut AppContext,
327 pub(crate) window: &'a mut Window,
328}
329
330impl<'a> WindowContext<'a> {
331 pub(crate) fn new(app: &'a mut AppContext, window: &'a mut Window) -> Self {
332 Self { app, window }
333 }
334
335 /// Obtain a handle to the window that belongs to this context.
336 pub fn window_handle(&self) -> AnyWindowHandle {
337 self.window.handle
338 }
339
340 /// Mark the window as dirty, scheduling it to be redrawn on the next frame.
341 pub fn notify(&mut self) {
342 self.window.dirty = true;
343 }
344
345 /// Obtain a new `FocusHandle`, which allows you to track and manipulate the keyboard focus
346 /// for elements rendered within this window.
347 pub fn focus_handle(&mut self) -> FocusHandle {
348 FocusHandle::new(&self.window.focus_handles)
349 }
350
351 /// Obtain the currently focused `FocusHandle`. If no elements are focused, returns `None`.
352 pub fn focused(&self) -> Option<FocusHandle> {
353 self.window
354 .focus
355 .and_then(|id| FocusHandle::for_id(id, &self.window.focus_handles))
356 }
357
358 /// Move focus to the element associated with the given `FocusHandle`.
359 pub fn focus(&mut self, handle: &FocusHandle) {
360 if self.window.last_blur.is_none() {
361 self.window.last_blur = Some(self.window.focus);
362 }
363
364 self.window.focus = Some(handle.id);
365 self.app.push_effect(Effect::FocusChanged {
366 window_handle: self.window.handle,
367 focused: Some(handle.id),
368 });
369 self.notify();
370 }
371
372 /// Remove focus from all elements within this context's window.
373 pub fn blur(&mut self) {
374 if self.window.last_blur.is_none() {
375 self.window.last_blur = Some(self.window.focus);
376 }
377
378 self.window.focus = None;
379 self.app.push_effect(Effect::FocusChanged {
380 window_handle: self.window.handle,
381 focused: None,
382 });
383 self.notify();
384 }
385
386 /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
387 /// that are currently on the stack to be returned to the app.
388 pub fn defer(&mut self, f: impl FnOnce(&mut WindowContext) + 'static) {
389 let handle = self.window.handle;
390 self.app.defer(move |cx| {
391 handle.update(cx, |_, cx| f(cx)).ok();
392 });
393 }
394
395 pub fn subscribe<Emitter, E>(
396 &mut self,
397 entity: &E,
398 mut on_event: impl FnMut(E, &Emitter::Event, &mut WindowContext<'_>) + 'static,
399 ) -> Subscription
400 where
401 Emitter: EventEmitter,
402 E: Entity<Emitter>,
403 {
404 let entity_id = entity.entity_id();
405 let entity = entity.downgrade();
406 let window_handle = self.window.handle;
407 self.app.event_listeners.insert(
408 entity_id,
409 Box::new(move |event, cx| {
410 window_handle
411 .update(cx, |_, cx| {
412 if let Some(handle) = E::upgrade_from(&entity) {
413 let event = event.downcast_ref().expect("invalid event type");
414 on_event(handle, event, cx);
415 true
416 } else {
417 false
418 }
419 })
420 .unwrap_or(false)
421 }),
422 )
423 }
424
425 /// Create an `AsyncWindowContext`, which has a static lifetime and can be held across
426 /// await points in async code.
427 pub fn to_async(&self) -> AsyncWindowContext {
428 AsyncWindowContext::new(self.app.to_async(), self.window.handle)
429 }
430
431 /// Schedule the given closure to be run directly after the current frame is rendered.
432 pub fn on_next_frame(&mut self, f: impl FnOnce(&mut WindowContext) + 'static) {
433 let f = Box::new(f);
434 let display_id = self.window.display_id;
435
436 if let Some(callbacks) = self.next_frame_callbacks.get_mut(&display_id) {
437 callbacks.push(f);
438 // If there was already a callback, it means that we already scheduled a frame.
439 if callbacks.len() > 1 {
440 return;
441 }
442 } else {
443 let mut async_cx = self.to_async();
444 self.next_frame_callbacks.insert(display_id, vec![f]);
445 self.platform.set_display_link_output_callback(
446 display_id,
447 Box::new(move |_current_time, _output_time| {
448 let _ = async_cx.update(|_, cx| {
449 let callbacks = cx
450 .next_frame_callbacks
451 .get_mut(&display_id)
452 .unwrap()
453 .drain(..)
454 .collect::<Vec<_>>();
455 for callback in callbacks {
456 callback(cx);
457 }
458
459 if cx.next_frame_callbacks.get(&display_id).unwrap().is_empty() {
460 cx.platform.stop_display_link(display_id);
461 }
462 });
463 }),
464 );
465 }
466
467 self.platform.start_display_link(display_id);
468 }
469
470 /// Spawn the future returned by the given closure on the application thread pool.
471 /// The closure is provided a handle to the current window and an `AsyncWindowContext` for
472 /// use within your future.
473 pub fn spawn<Fut, R>(&mut self, f: impl FnOnce(AsyncWindowContext) -> Fut) -> Task<R>
474 where
475 R: 'static,
476 Fut: Future<Output = R> + 'static,
477 {
478 self.app
479 .spawn(|app| f(AsyncWindowContext::new(app, self.window.handle)))
480 }
481
482 /// Update the global of the given type. The given closure is given simultaneous mutable
483 /// access both to the global and the context.
484 pub fn update_global<G, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R
485 where
486 G: 'static,
487 {
488 let mut global = self.app.lease_global::<G>();
489 let result = f(&mut global, self);
490 self.app.end_global_lease(global);
491 result
492 }
493
494 /// Add a node to the layout tree for the current frame. Takes the `Style` of the element for which
495 /// layout is being requested, along with the layout ids of any children. This method is called during
496 /// calls to the `Element::layout` trait method and enables any element to participate in layout.
497 pub fn request_layout(
498 &mut self,
499 style: &Style,
500 children: impl IntoIterator<Item = LayoutId>,
501 ) -> LayoutId {
502 self.app.layout_id_buffer.clear();
503 self.app.layout_id_buffer.extend(children.into_iter());
504 let rem_size = self.rem_size();
505
506 self.window
507 .layout_engine
508 .request_layout(style, rem_size, &self.app.layout_id_buffer)
509 }
510
511 /// Add a node to the layout tree for the current frame. Instead of taking a `Style` and children,
512 /// this variant takes a function that is invoked during layout so you can use arbitrary logic to
513 /// determine the element's size. One place this is used internally is when measuring text.
514 ///
515 /// The given closure is invoked at layout time with the known dimensions and available space and
516 /// returns a `Size`.
517 pub fn request_measured_layout<
518 F: Fn(Size<Option<Pixels>>, Size<AvailableSpace>) -> Size<Pixels> + Send + Sync + 'static,
519 >(
520 &mut self,
521 style: Style,
522 rem_size: Pixels,
523 measure: F,
524 ) -> LayoutId {
525 self.window
526 .layout_engine
527 .request_measured_layout(style, rem_size, measure)
528 }
529
530 /// Obtain the bounds computed for the given LayoutId relative to the window. This method should not
531 /// be invoked until the paint phase begins, and will usually be invoked by GPUI itself automatically
532 /// in order to pass your element its `Bounds` automatically.
533 pub fn layout_bounds(&mut self, layout_id: LayoutId) -> Bounds<Pixels> {
534 let mut bounds = self
535 .window
536 .layout_engine
537 .layout_bounds(layout_id)
538 .map(Into::into);
539 bounds.origin += self.element_offset();
540 bounds
541 }
542
543 /// The scale factor of the display associated with the window. For example, it could
544 /// return 2.0 for a "retina" display, indicating that each logical pixel should actually
545 /// be rendered as two pixels on screen.
546 pub fn scale_factor(&self) -> f32 {
547 self.window.scale_factor
548 }
549
550 /// The size of an em for the base font of the application. Adjusting this value allows the
551 /// UI to scale, just like zooming a web page.
552 pub fn rem_size(&self) -> Pixels {
553 self.window.rem_size
554 }
555
556 /// Sets the size of an em for the base font of the application. Adjusting this value allows the
557 /// UI to scale, just like zooming a web page.
558 pub fn set_rem_size(&mut self, rem_size: impl Into<Pixels>) {
559 self.window.rem_size = rem_size.into();
560 }
561
562 /// The line height associated with the current text style.
563 pub fn line_height(&self) -> Pixels {
564 let rem_size = self.rem_size();
565 let text_style = self.text_style();
566 text_style
567 .line_height
568 .to_pixels(text_style.font_size.into(), rem_size)
569 }
570
571 /// Call to prevent the default action of an event. Currently only used to prevent
572 /// parent elements from becoming focused on mouse down.
573 pub fn prevent_default(&mut self) {
574 self.window.default_prevented = true;
575 }
576
577 /// Obtain whether default has been prevented for the event currently being dispatched.
578 pub fn default_prevented(&self) -> bool {
579 self.window.default_prevented
580 }
581
582 /// Register a mouse event listener on the window for the current frame. The type of event
583 /// is determined by the first parameter of the given listener. When the next frame is rendered
584 /// the listener will be cleared.
585 ///
586 /// This is a fairly low-level method, so prefer using event handlers on elements unless you have
587 /// a specific need to register a global listener.
588 pub fn on_mouse_event<Event: 'static>(
589 &mut self,
590 handler: impl Fn(&Event, DispatchPhase, &mut WindowContext) + 'static,
591 ) {
592 let order = self.window.z_index_stack.clone();
593 self.window
594 .mouse_listeners
595 .entry(TypeId::of::<Event>())
596 .or_default()
597 .push((
598 order,
599 Box::new(move |event: &dyn Any, phase, cx| {
600 handler(event.downcast_ref().unwrap(), phase, cx)
601 }),
602 ))
603 }
604
605 /// The position of the mouse relative to the window.
606 pub fn mouse_position(&self) -> Point<Pixels> {
607 self.window.mouse_position
608 }
609
610 /// Called during painting to invoke the given closure in a new stacking context. The given
611 /// z-index is interpreted relative to the previous call to `stack`.
612 pub fn stack<R>(&mut self, z_index: u32, f: impl FnOnce(&mut Self) -> R) -> R {
613 self.window.z_index_stack.push(z_index);
614 let result = f(self);
615 self.window.z_index_stack.pop();
616 result
617 }
618
619 /// Paint one or more drop shadows into the scene for the current frame at the current z-index.
620 pub fn paint_shadows(
621 &mut self,
622 bounds: Bounds<Pixels>,
623 corner_radii: Corners<Pixels>,
624 shadows: &[BoxShadow],
625 ) {
626 let scale_factor = self.scale_factor();
627 let content_mask = self.content_mask();
628 let window = &mut *self.window;
629 for shadow in shadows {
630 let mut shadow_bounds = bounds;
631 shadow_bounds.origin += shadow.offset;
632 shadow_bounds.dilate(shadow.spread_radius);
633 window.scene_builder.insert(
634 &window.z_index_stack,
635 Shadow {
636 order: 0,
637 bounds: shadow_bounds.scale(scale_factor),
638 content_mask: content_mask.scale(scale_factor),
639 corner_radii: corner_radii.scale(scale_factor),
640 color: shadow.color,
641 blur_radius: shadow.blur_radius.scale(scale_factor),
642 },
643 );
644 }
645 }
646
647 /// Paint one or more quads into the scene for the current frame at the current stacking context.
648 /// Quads are colored rectangular regions with an optional background, border, and corner radius.
649 pub fn paint_quad(
650 &mut self,
651 bounds: Bounds<Pixels>,
652 corner_radii: Corners<Pixels>,
653 background: impl Into<Hsla>,
654 border_widths: Edges<Pixels>,
655 border_color: impl Into<Hsla>,
656 ) {
657 let scale_factor = self.scale_factor();
658 let content_mask = self.content_mask();
659
660 let window = &mut *self.window;
661 window.scene_builder.insert(
662 &window.z_index_stack,
663 Quad {
664 order: 0,
665 bounds: bounds.scale(scale_factor),
666 content_mask: content_mask.scale(scale_factor),
667 background: background.into(),
668 border_color: border_color.into(),
669 corner_radii: corner_radii.scale(scale_factor),
670 border_widths: border_widths.scale(scale_factor),
671 },
672 );
673 }
674
675 /// Paint the given `Path` into the scene for the current frame at the current z-index.
676 pub fn paint_path(&mut self, mut path: Path<Pixels>, color: impl Into<Hsla>) {
677 let scale_factor = self.scale_factor();
678 let content_mask = self.content_mask();
679 path.content_mask = content_mask;
680 path.color = color.into();
681 let window = &mut *self.window;
682 window
683 .scene_builder
684 .insert(&window.z_index_stack, path.scale(scale_factor));
685 }
686
687 /// Paint an underline into the scene for the current frame at the current z-index.
688 pub fn paint_underline(
689 &mut self,
690 origin: Point<Pixels>,
691 width: Pixels,
692 style: &UnderlineStyle,
693 ) -> Result<()> {
694 let scale_factor = self.scale_factor();
695 let height = if style.wavy {
696 style.thickness * 3.
697 } else {
698 style.thickness
699 };
700 let bounds = Bounds {
701 origin,
702 size: size(width, height),
703 };
704 let content_mask = self.content_mask();
705 let window = &mut *self.window;
706 window.scene_builder.insert(
707 &window.z_index_stack,
708 Underline {
709 order: 0,
710 bounds: bounds.scale(scale_factor),
711 content_mask: content_mask.scale(scale_factor),
712 thickness: style.thickness.scale(scale_factor),
713 color: style.color.unwrap_or_default(),
714 wavy: style.wavy,
715 },
716 );
717 Ok(())
718 }
719
720 /// Paint a monochrome (non-emoji) glyph into the scene for the current frame at the current z-index.
721 pub fn paint_glyph(
722 &mut self,
723 origin: Point<Pixels>,
724 font_id: FontId,
725 glyph_id: GlyphId,
726 font_size: Pixels,
727 color: Hsla,
728 ) -> Result<()> {
729 let scale_factor = self.scale_factor();
730 let glyph_origin = origin.scale(scale_factor);
731 let subpixel_variant = Point {
732 x: (glyph_origin.x.0.fract() * SUBPIXEL_VARIANTS as f32).floor() as u8,
733 y: (glyph_origin.y.0.fract() * SUBPIXEL_VARIANTS as f32).floor() as u8,
734 };
735 let params = RenderGlyphParams {
736 font_id,
737 glyph_id,
738 font_size,
739 subpixel_variant,
740 scale_factor,
741 is_emoji: false,
742 };
743
744 let raster_bounds = self.text_system().raster_bounds(¶ms)?;
745 if !raster_bounds.is_zero() {
746 let tile =
747 self.window
748 .sprite_atlas
749 .get_or_insert_with(¶ms.clone().into(), &mut || {
750 let (size, bytes) = self.text_system().rasterize_glyph(¶ms)?;
751 Ok((size, Cow::Owned(bytes)))
752 })?;
753 let bounds = Bounds {
754 origin: glyph_origin.map(|px| px.floor()) + raster_bounds.origin.map(Into::into),
755 size: tile.bounds.size.map(Into::into),
756 };
757 let content_mask = self.content_mask().scale(scale_factor);
758 let window = &mut *self.window;
759 window.scene_builder.insert(
760 &window.z_index_stack,
761 MonochromeSprite {
762 order: 0,
763 bounds,
764 content_mask,
765 color,
766 tile,
767 },
768 );
769 }
770 Ok(())
771 }
772
773 /// Paint an emoji glyph into the scene for the current frame at the current z-index.
774 pub fn paint_emoji(
775 &mut self,
776 origin: Point<Pixels>,
777 font_id: FontId,
778 glyph_id: GlyphId,
779 font_size: Pixels,
780 ) -> Result<()> {
781 let scale_factor = self.scale_factor();
782 let glyph_origin = origin.scale(scale_factor);
783 let params = RenderGlyphParams {
784 font_id,
785 glyph_id,
786 font_size,
787 // We don't render emojis with subpixel variants.
788 subpixel_variant: Default::default(),
789 scale_factor,
790 is_emoji: true,
791 };
792
793 let raster_bounds = self.text_system().raster_bounds(¶ms)?;
794 if !raster_bounds.is_zero() {
795 let tile =
796 self.window
797 .sprite_atlas
798 .get_or_insert_with(¶ms.clone().into(), &mut || {
799 let (size, bytes) = self.text_system().rasterize_glyph(¶ms)?;
800 Ok((size, Cow::Owned(bytes)))
801 })?;
802 let bounds = Bounds {
803 origin: glyph_origin.map(|px| px.floor()) + raster_bounds.origin.map(Into::into),
804 size: tile.bounds.size.map(Into::into),
805 };
806 let content_mask = self.content_mask().scale(scale_factor);
807 let window = &mut *self.window;
808
809 window.scene_builder.insert(
810 &window.z_index_stack,
811 PolychromeSprite {
812 order: 0,
813 bounds,
814 corner_radii: Default::default(),
815 content_mask,
816 tile,
817 grayscale: false,
818 },
819 );
820 }
821 Ok(())
822 }
823
824 /// Paint a monochrome SVG into the scene for the current frame at the current stacking context.
825 pub fn paint_svg(
826 &mut self,
827 bounds: Bounds<Pixels>,
828 path: SharedString,
829 color: Hsla,
830 ) -> Result<()> {
831 let scale_factor = self.scale_factor();
832 let bounds = bounds.scale(scale_factor);
833 // Render the SVG at twice the size to get a higher quality result.
834 let params = RenderSvgParams {
835 path,
836 size: bounds
837 .size
838 .map(|pixels| DevicePixels::from((pixels.0 * 2.).ceil() as i32)),
839 };
840
841 let tile =
842 self.window
843 .sprite_atlas
844 .get_or_insert_with(¶ms.clone().into(), &mut || {
845 let bytes = self.svg_renderer.render(¶ms)?;
846 Ok((params.size, Cow::Owned(bytes)))
847 })?;
848 let content_mask = self.content_mask().scale(scale_factor);
849
850 let window = &mut *self.window;
851 window.scene_builder.insert(
852 &window.z_index_stack,
853 MonochromeSprite {
854 order: 0,
855 bounds,
856 content_mask,
857 color,
858 tile,
859 },
860 );
861
862 Ok(())
863 }
864
865 /// Paint an image into the scene for the current frame at the current z-index.
866 pub fn paint_image(
867 &mut self,
868 bounds: Bounds<Pixels>,
869 corner_radii: Corners<Pixels>,
870 data: Arc<ImageData>,
871 grayscale: bool,
872 ) -> Result<()> {
873 let scale_factor = self.scale_factor();
874 let bounds = bounds.scale(scale_factor);
875 let params = RenderImageParams { image_id: data.id };
876
877 let tile = self
878 .window
879 .sprite_atlas
880 .get_or_insert_with(¶ms.clone().into(), &mut || {
881 Ok((data.size(), Cow::Borrowed(data.as_bytes())))
882 })?;
883 let content_mask = self.content_mask().scale(scale_factor);
884 let corner_radii = corner_radii.scale(scale_factor);
885
886 let window = &mut *self.window;
887 window.scene_builder.insert(
888 &window.z_index_stack,
889 PolychromeSprite {
890 order: 0,
891 bounds,
892 content_mask,
893 corner_radii,
894 tile,
895 grayscale,
896 },
897 );
898 Ok(())
899 }
900
901 /// Draw pixels to the display for this window based on the contents of its scene.
902 pub(crate) fn draw(&mut self) {
903 let root_view = self.window.root_view.take().unwrap();
904
905 self.start_frame();
906
907 self.stack(0, |cx| {
908 let available_space = cx.window.content_size.map(Into::into);
909 root_view.draw(available_space, cx);
910 });
911
912 if let Some(active_drag) = self.app.active_drag.take() {
913 self.stack(1, |cx| {
914 let offset = cx.mouse_position() - active_drag.cursor_offset;
915 cx.with_element_offset(Some(offset), |cx| {
916 let available_space =
917 size(AvailableSpace::MinContent, AvailableSpace::MinContent);
918 active_drag.view.draw(available_space, cx);
919 cx.active_drag = Some(active_drag);
920 });
921 });
922 }
923
924 self.window.root_view = Some(root_view);
925 let scene = self.window.scene_builder.build();
926
927 self.window.platform_window.draw(scene);
928 self.window.dirty = false;
929 }
930
931 fn start_frame(&mut self) {
932 self.text_system().start_frame();
933
934 let window = &mut *self.window;
935
936 // Move the current frame element states to the previous frame.
937 // The new empty element states map will be populated for any element states we
938 // reference during the upcoming frame.
939 mem::swap(
940 &mut window.element_states,
941 &mut window.prev_frame_element_states,
942 );
943 window.element_states.clear();
944
945 // Make the current key matchers the previous, and then clear the current.
946 // An empty key matcher map will be created for every identified element in the
947 // upcoming frame.
948 mem::swap(
949 &mut window.key_matchers,
950 &mut window.prev_frame_key_matchers,
951 );
952 window.key_matchers.clear();
953
954 // Clear mouse event listeners, because elements add new element listeners
955 // when the upcoming frame is painted.
956 window.mouse_listeners.values_mut().for_each(Vec::clear);
957
958 // Clear focus state, because we determine what is focused when the new elements
959 // in the upcoming frame are initialized.
960 window.focus_listeners.clear();
961 window.key_dispatch_stack.clear();
962 window.focus_parents_by_child.clear();
963 window.freeze_key_dispatch_stack = false;
964 }
965
966 /// Dispatch a mouse or keyboard event on the window.
967 fn dispatch_event(&mut self, event: InputEvent) -> bool {
968 let event = match event {
969 // Track the mouse position with our own state, since accessing the platform
970 // API for the mouse position can only occur on the main thread.
971 InputEvent::MouseMove(mouse_move) => {
972 self.window.mouse_position = mouse_move.position;
973 InputEvent::MouseMove(mouse_move)
974 }
975 // Translate dragging and dropping of external files from the operating system
976 // to internal drag and drop events.
977 InputEvent::FileDrop(file_drop) => match file_drop {
978 FileDropEvent::Entered { position, files } => {
979 self.window.mouse_position = position;
980 if self.active_drag.is_none() {
981 self.active_drag = Some(AnyDrag {
982 view: self.build_view(|_| files).into(),
983 cursor_offset: position,
984 });
985 }
986 InputEvent::MouseDown(MouseDownEvent {
987 position,
988 button: MouseButton::Left,
989 click_count: 1,
990 modifiers: Modifiers::default(),
991 })
992 }
993 FileDropEvent::Pending { position } => {
994 self.window.mouse_position = position;
995 InputEvent::MouseMove(MouseMoveEvent {
996 position,
997 pressed_button: Some(MouseButton::Left),
998 modifiers: Modifiers::default(),
999 })
1000 }
1001 FileDropEvent::Submit { position } => {
1002 self.window.mouse_position = position;
1003 InputEvent::MouseUp(MouseUpEvent {
1004 button: MouseButton::Left,
1005 position,
1006 modifiers: Modifiers::default(),
1007 click_count: 1,
1008 })
1009 }
1010 FileDropEvent::Exited => InputEvent::MouseUp(MouseUpEvent {
1011 button: MouseButton::Left,
1012 position: Point::default(),
1013 modifiers: Modifiers::default(),
1014 click_count: 1,
1015 }),
1016 },
1017 _ => event,
1018 };
1019
1020 if let Some(any_mouse_event) = event.mouse_event() {
1021 // Handlers may set this to false by calling `stop_propagation`
1022 self.app.propagate_event = true;
1023 self.window.default_prevented = false;
1024
1025 if let Some(mut handlers) = self
1026 .window
1027 .mouse_listeners
1028 .remove(&any_mouse_event.type_id())
1029 {
1030 // Because handlers may add other handlers, we sort every time.
1031 handlers.sort_by(|(a, _), (b, _)| a.cmp(b));
1032
1033 // Capture phase, events bubble from back to front. Handlers for this phase are used for
1034 // special purposes, such as detecting events outside of a given Bounds.
1035 for (_, handler) in &handlers {
1036 handler(any_mouse_event, DispatchPhase::Capture, self);
1037 if !self.app.propagate_event {
1038 break;
1039 }
1040 }
1041
1042 // Bubble phase, where most normal handlers do their work.
1043 if self.app.propagate_event {
1044 for (_, handler) in handlers.iter().rev() {
1045 handler(any_mouse_event, DispatchPhase::Bubble, self);
1046 if !self.app.propagate_event {
1047 break;
1048 }
1049 }
1050 }
1051
1052 if self.app.propagate_event
1053 && any_mouse_event.downcast_ref::<MouseUpEvent>().is_some()
1054 {
1055 self.active_drag = None;
1056 }
1057
1058 // Just in case any handlers added new handlers, which is weird, but possible.
1059 handlers.extend(
1060 self.window
1061 .mouse_listeners
1062 .get_mut(&any_mouse_event.type_id())
1063 .into_iter()
1064 .flat_map(|handlers| handlers.drain(..)),
1065 );
1066 self.window
1067 .mouse_listeners
1068 .insert(any_mouse_event.type_id(), handlers);
1069 }
1070 } else if let Some(any_key_event) = event.keyboard_event() {
1071 let key_dispatch_stack = mem::take(&mut self.window.key_dispatch_stack);
1072 let key_event_type = any_key_event.type_id();
1073 let mut context_stack = SmallVec::<[&DispatchContext; 16]>::new();
1074
1075 for (ix, frame) in key_dispatch_stack.iter().enumerate() {
1076 match frame {
1077 KeyDispatchStackFrame::Listener {
1078 event_type,
1079 listener,
1080 } => {
1081 if key_event_type == *event_type {
1082 if let Some(action) = listener(
1083 any_key_event,
1084 &context_stack,
1085 DispatchPhase::Capture,
1086 self,
1087 ) {
1088 self.dispatch_action(action, &key_dispatch_stack[..ix]);
1089 }
1090 if !self.app.propagate_event {
1091 break;
1092 }
1093 }
1094 }
1095 KeyDispatchStackFrame::Context(context) => {
1096 context_stack.push(&context);
1097 }
1098 }
1099 }
1100
1101 if self.app.propagate_event {
1102 for (ix, frame) in key_dispatch_stack.iter().enumerate().rev() {
1103 match frame {
1104 KeyDispatchStackFrame::Listener {
1105 event_type,
1106 listener,
1107 } => {
1108 if key_event_type == *event_type {
1109 if let Some(action) = listener(
1110 any_key_event,
1111 &context_stack,
1112 DispatchPhase::Bubble,
1113 self,
1114 ) {
1115 self.dispatch_action(action, &key_dispatch_stack[..ix]);
1116 }
1117
1118 if !self.app.propagate_event {
1119 break;
1120 }
1121 }
1122 }
1123 KeyDispatchStackFrame::Context(_) => {
1124 context_stack.pop();
1125 }
1126 }
1127 }
1128 }
1129
1130 drop(context_stack);
1131 self.window.key_dispatch_stack = key_dispatch_stack;
1132 }
1133
1134 true
1135 }
1136
1137 /// Attempt to map a keystroke to an action based on the keymap.
1138 pub fn match_keystroke(
1139 &mut self,
1140 element_id: &GlobalElementId,
1141 keystroke: &Keystroke,
1142 context_stack: &[&DispatchContext],
1143 ) -> KeyMatch {
1144 let key_match = self
1145 .window
1146 .key_matchers
1147 .get_mut(element_id)
1148 .unwrap()
1149 .match_keystroke(keystroke, context_stack);
1150
1151 if key_match.is_some() {
1152 for matcher in self.window.key_matchers.values_mut() {
1153 matcher.clear_pending();
1154 }
1155 }
1156
1157 key_match
1158 }
1159
1160 /// Register the given handler to be invoked whenever the global of the given type
1161 /// is updated.
1162 pub fn observe_global<G: 'static>(
1163 &mut self,
1164 f: impl Fn(&mut WindowContext<'_>) + 'static,
1165 ) -> Subscription {
1166 let window_handle = self.window.handle;
1167 self.global_observers.insert(
1168 TypeId::of::<G>(),
1169 Box::new(move |cx| window_handle.update(cx, |_, cx| f(cx)).is_ok()),
1170 )
1171 }
1172
1173 pub fn activate_window(&self) {
1174 self.window.platform_window.activate();
1175 }
1176
1177 pub fn prompt(
1178 &self,
1179 level: PromptLevel,
1180 msg: &str,
1181 answers: &[&str],
1182 ) -> oneshot::Receiver<usize> {
1183 self.window.platform_window.prompt(level, msg, answers)
1184 }
1185
1186 fn dispatch_action(
1187 &mut self,
1188 action: Box<dyn Action>,
1189 dispatch_stack: &[KeyDispatchStackFrame],
1190 ) {
1191 let action_type = action.as_any().type_id();
1192
1193 if let Some(mut global_listeners) = self.app.global_action_listeners.remove(&action_type) {
1194 for listener in &global_listeners {
1195 listener(action.as_ref(), DispatchPhase::Capture, self);
1196 if !self.app.propagate_event {
1197 break;
1198 }
1199 }
1200 global_listeners.extend(
1201 self.global_action_listeners
1202 .remove(&action_type)
1203 .unwrap_or_default(),
1204 );
1205 self.global_action_listeners
1206 .insert(action_type, global_listeners);
1207 }
1208
1209 if self.app.propagate_event {
1210 for stack_frame in dispatch_stack {
1211 if let KeyDispatchStackFrame::Listener {
1212 event_type,
1213 listener,
1214 } = stack_frame
1215 {
1216 if action_type == *event_type {
1217 listener(action.as_any(), &[], DispatchPhase::Capture, self);
1218 if !self.app.propagate_event {
1219 break;
1220 }
1221 }
1222 }
1223 }
1224 }
1225
1226 if self.app.propagate_event {
1227 for stack_frame in dispatch_stack.iter().rev() {
1228 if let KeyDispatchStackFrame::Listener {
1229 event_type,
1230 listener,
1231 } = stack_frame
1232 {
1233 if action_type == *event_type {
1234 listener(action.as_any(), &[], DispatchPhase::Bubble, self);
1235 if !self.app.propagate_event {
1236 break;
1237 }
1238 }
1239 }
1240 }
1241 }
1242
1243 if self.app.propagate_event {
1244 if let Some(mut global_listeners) =
1245 self.app.global_action_listeners.remove(&action_type)
1246 {
1247 for listener in global_listeners.iter().rev() {
1248 listener(action.as_ref(), DispatchPhase::Bubble, self);
1249 if !self.app.propagate_event {
1250 break;
1251 }
1252 }
1253 global_listeners.extend(
1254 self.global_action_listeners
1255 .remove(&action_type)
1256 .unwrap_or_default(),
1257 );
1258 self.global_action_listeners
1259 .insert(action_type, global_listeners);
1260 }
1261 }
1262 }
1263}
1264
1265impl Context for WindowContext<'_> {
1266 type Result<T> = T;
1267
1268 fn build_model<T>(
1269 &mut self,
1270 build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
1271 ) -> Model<T>
1272 where
1273 T: 'static,
1274 {
1275 let slot = self.app.entities.reserve();
1276 let model = build_model(&mut ModelContext::new(&mut *self.app, slot.downgrade()));
1277 self.entities.insert(slot, model)
1278 }
1279
1280 fn update_model<T: 'static, R>(
1281 &mut self,
1282 model: &Model<T>,
1283 update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
1284 ) -> R {
1285 let mut entity = self.entities.lease(model);
1286 let result = update(
1287 &mut *entity,
1288 &mut ModelContext::new(&mut *self.app, model.downgrade()),
1289 );
1290 self.entities.end_lease(entity);
1291 result
1292 }
1293
1294 fn update_window<T, F>(&mut self, window: AnyWindowHandle, update: F) -> Result<T>
1295 where
1296 F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
1297 {
1298 if window == self.window.handle {
1299 let root_view = self.window.root_view.clone().unwrap();
1300 Ok(update(root_view, self))
1301 } else {
1302 window.update(self.app, update)
1303 }
1304 }
1305}
1306
1307impl VisualContext for WindowContext<'_> {
1308 fn build_view<V>(
1309 &mut self,
1310 build_view_state: impl FnOnce(&mut ViewContext<'_, V>) -> V,
1311 ) -> Self::Result<View<V>>
1312 where
1313 V: 'static,
1314 {
1315 let slot = self.app.entities.reserve();
1316 let view = View {
1317 model: slot.clone(),
1318 };
1319 let mut cx = ViewContext::new(&mut *self.app, &mut *self.window, &view);
1320 let entity = build_view_state(&mut cx);
1321 self.entities.insert(slot, entity);
1322 view
1323 }
1324
1325 /// Update the given view. Prefer calling `View::update` instead, which calls this method.
1326 fn update_view<T: 'static, R>(
1327 &mut self,
1328 view: &View<T>,
1329 update: impl FnOnce(&mut T, &mut ViewContext<'_, T>) -> R,
1330 ) -> Self::Result<R> {
1331 let mut lease = self.app.entities.lease(&view.model);
1332 let mut cx = ViewContext::new(&mut *self.app, &mut *self.window, &view);
1333 let result = update(&mut *lease, &mut cx);
1334 cx.app.entities.end_lease(lease);
1335 result
1336 }
1337
1338 fn replace_root_view<V>(
1339 &mut self,
1340 build_view: impl FnOnce(&mut ViewContext<'_, V>) -> V,
1341 ) -> Self::Result<View<V>>
1342 where
1343 V: Render,
1344 {
1345 let slot = self.app.entities.reserve();
1346 let view = View {
1347 model: slot.clone(),
1348 };
1349 let mut cx = ViewContext::new(&mut *self.app, &mut *self.window, &view);
1350 let entity = build_view(&mut cx);
1351 self.entities.insert(slot, entity);
1352 self.window.root_view = Some(view.clone().into());
1353 view
1354 }
1355}
1356
1357impl<'a> std::ops::Deref for WindowContext<'a> {
1358 type Target = AppContext;
1359
1360 fn deref(&self) -> &Self::Target {
1361 &self.app
1362 }
1363}
1364
1365impl<'a> std::ops::DerefMut for WindowContext<'a> {
1366 fn deref_mut(&mut self) -> &mut Self::Target {
1367 &mut self.app
1368 }
1369}
1370
1371impl<'a> Borrow<AppContext> for WindowContext<'a> {
1372 fn borrow(&self) -> &AppContext {
1373 &self.app
1374 }
1375}
1376
1377impl<'a> BorrowMut<AppContext> for WindowContext<'a> {
1378 fn borrow_mut(&mut self) -> &mut AppContext {
1379 &mut self.app
1380 }
1381}
1382
1383pub trait BorrowWindow: BorrowMut<Window> + BorrowMut<AppContext> {
1384 fn app_mut(&mut self) -> &mut AppContext {
1385 self.borrow_mut()
1386 }
1387
1388 fn window(&self) -> &Window {
1389 self.borrow()
1390 }
1391
1392 fn window_mut(&mut self) -> &mut Window {
1393 self.borrow_mut()
1394 }
1395
1396 /// Pushes the given element id onto the global stack and invokes the given closure
1397 /// with a `GlobalElementId`, which disambiguates the given id in the context of its ancestor
1398 /// ids. Because elements are discarded and recreated on each frame, the `GlobalElementId` is
1399 /// used to associate state with identified elements across separate frames.
1400 fn with_element_id<R>(
1401 &mut self,
1402 id: impl Into<ElementId>,
1403 f: impl FnOnce(GlobalElementId, &mut Self) -> R,
1404 ) -> R {
1405 let keymap = self.app_mut().keymap.clone();
1406 let window = self.window_mut();
1407 window.element_id_stack.push(id.into());
1408 let global_id = window.element_id_stack.clone();
1409
1410 if window.key_matchers.get(&global_id).is_none() {
1411 window.key_matchers.insert(
1412 global_id.clone(),
1413 window
1414 .prev_frame_key_matchers
1415 .remove(&global_id)
1416 .unwrap_or_else(|| KeyMatcher::new(keymap)),
1417 );
1418 }
1419
1420 let result = f(global_id, self);
1421 let window: &mut Window = self.borrow_mut();
1422 window.element_id_stack.pop();
1423 result
1424 }
1425
1426 /// Invoke the given function with the given content mask after intersecting it
1427 /// with the current mask.
1428 fn with_content_mask<R>(
1429 &mut self,
1430 mask: ContentMask<Pixels>,
1431 f: impl FnOnce(&mut Self) -> R,
1432 ) -> R {
1433 let mask = mask.intersect(&self.content_mask());
1434 self.window_mut().content_mask_stack.push(mask);
1435 let result = f(self);
1436 self.window_mut().content_mask_stack.pop();
1437 result
1438 }
1439
1440 /// Update the global element offset based on the given offset. This is used to implement
1441 /// scrolling and position drag handles.
1442 fn with_element_offset<R>(
1443 &mut self,
1444 offset: Option<Point<Pixels>>,
1445 f: impl FnOnce(&mut Self) -> R,
1446 ) -> R {
1447 let Some(offset) = offset else {
1448 return f(self);
1449 };
1450
1451 let offset = self.element_offset() + offset;
1452 self.window_mut().element_offset_stack.push(offset);
1453 let result = f(self);
1454 self.window_mut().element_offset_stack.pop();
1455 result
1456 }
1457
1458 /// Obtain the current element offset.
1459 fn element_offset(&self) -> Point<Pixels> {
1460 self.window()
1461 .element_offset_stack
1462 .last()
1463 .copied()
1464 .unwrap_or_default()
1465 }
1466
1467 /// Update or intialize state for an element with the given id that lives across multiple
1468 /// frames. If an element with this id existed in the previous frame, its state will be passed
1469 /// to the given closure. The state returned by the closure will be stored so it can be referenced
1470 /// when drawing the next frame.
1471 fn with_element_state<S, R>(
1472 &mut self,
1473 id: ElementId,
1474 f: impl FnOnce(Option<S>, &mut Self) -> (R, S),
1475 ) -> R
1476 where
1477 S: 'static,
1478 {
1479 self.with_element_id(id, |global_id, cx| {
1480 if let Some(any) = cx
1481 .window_mut()
1482 .element_states
1483 .remove(&global_id)
1484 .or_else(|| cx.window_mut().prev_frame_element_states.remove(&global_id))
1485 {
1486 // Using the extra inner option to avoid needing to reallocate a new box.
1487 let mut state_box = any
1488 .downcast::<Option<S>>()
1489 .expect("invalid element state type for id");
1490 let state = state_box
1491 .take()
1492 .expect("element state is already on the stack");
1493 let (result, state) = f(Some(state), cx);
1494 state_box.replace(state);
1495 cx.window_mut().element_states.insert(global_id, state_box);
1496 result
1497 } else {
1498 let (result, state) = f(None, cx);
1499 cx.window_mut()
1500 .element_states
1501 .insert(global_id, Box::new(Some(state)));
1502 result
1503 }
1504 })
1505 }
1506
1507 /// Like `with_element_state`, but for situations where the element_id is optional. If the
1508 /// id is `None`, no state will be retrieved or stored.
1509 fn with_optional_element_state<S, R>(
1510 &mut self,
1511 element_id: Option<ElementId>,
1512 f: impl FnOnce(Option<S>, &mut Self) -> (R, S),
1513 ) -> R
1514 where
1515 S: 'static,
1516 {
1517 if let Some(element_id) = element_id {
1518 self.with_element_state(element_id, f)
1519 } else {
1520 f(None, self).0
1521 }
1522 }
1523
1524 /// Obtain the current content mask.
1525 fn content_mask(&self) -> ContentMask<Pixels> {
1526 self.window()
1527 .content_mask_stack
1528 .last()
1529 .cloned()
1530 .unwrap_or_else(|| ContentMask {
1531 bounds: Bounds {
1532 origin: Point::default(),
1533 size: self.window().content_size,
1534 },
1535 })
1536 }
1537
1538 /// The size of an em for the base font of the application. Adjusting this value allows the
1539 /// UI to scale, just like zooming a web page.
1540 fn rem_size(&self) -> Pixels {
1541 self.window().rem_size
1542 }
1543}
1544
1545impl Borrow<Window> for WindowContext<'_> {
1546 fn borrow(&self) -> &Window {
1547 &self.window
1548 }
1549}
1550
1551impl BorrowMut<Window> for WindowContext<'_> {
1552 fn borrow_mut(&mut self) -> &mut Window {
1553 &mut self.window
1554 }
1555}
1556
1557impl<T> BorrowWindow for T where T: BorrowMut<AppContext> + BorrowMut<Window> {}
1558
1559pub struct ViewContext<'a, V> {
1560 window_cx: WindowContext<'a>,
1561 view: &'a View<V>,
1562}
1563
1564impl<V> Borrow<AppContext> for ViewContext<'_, V> {
1565 fn borrow(&self) -> &AppContext {
1566 &*self.window_cx.app
1567 }
1568}
1569
1570impl<V> BorrowMut<AppContext> for ViewContext<'_, V> {
1571 fn borrow_mut(&mut self) -> &mut AppContext {
1572 &mut *self.window_cx.app
1573 }
1574}
1575
1576impl<V> Borrow<Window> for ViewContext<'_, V> {
1577 fn borrow(&self) -> &Window {
1578 &*self.window_cx.window
1579 }
1580}
1581
1582impl<V> BorrowMut<Window> for ViewContext<'_, V> {
1583 fn borrow_mut(&mut self) -> &mut Window {
1584 &mut *self.window_cx.window
1585 }
1586}
1587
1588impl<'a, V: 'static> ViewContext<'a, V> {
1589 pub(crate) fn new(app: &'a mut AppContext, window: &'a mut Window, view: &'a View<V>) -> Self {
1590 Self {
1591 window_cx: WindowContext::new(app, window),
1592 view,
1593 }
1594 }
1595
1596 pub fn view(&self) -> View<V> {
1597 self.view.clone()
1598 }
1599
1600 pub fn model(&self) -> Model<V> {
1601 self.view.model.clone()
1602 }
1603
1604 pub fn stack<R>(&mut self, order: u32, f: impl FnOnce(&mut Self) -> R) -> R {
1605 self.window.z_index_stack.push(order);
1606 let result = f(self);
1607 self.window.z_index_stack.pop();
1608 result
1609 }
1610
1611 pub fn on_next_frame(&mut self, f: impl FnOnce(&mut V, &mut ViewContext<V>) + 'static)
1612 where
1613 V: 'static,
1614 {
1615 let view = self.view();
1616 self.window_cx.on_next_frame(move |cx| view.update(cx, f));
1617 }
1618
1619 /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
1620 /// that are currently on the stack to be returned to the app.
1621 pub fn defer(&mut self, f: impl FnOnce(&mut V, &mut ViewContext<V>) + 'static) {
1622 let view = self.view().downgrade();
1623 self.window_cx.defer(move |cx| {
1624 view.update(cx, f).ok();
1625 });
1626 }
1627
1628 pub fn observe<V2, E>(
1629 &mut self,
1630 entity: &E,
1631 mut on_notify: impl FnMut(&mut V, E, &mut ViewContext<'_, V>) + 'static,
1632 ) -> Subscription
1633 where
1634 V2: 'static,
1635 V: 'static,
1636 E: Entity<V2>,
1637 {
1638 let view = self.view().downgrade();
1639 let entity_id = entity.entity_id();
1640 let entity = entity.downgrade();
1641 let window_handle = self.window.handle;
1642 self.app.observers.insert(
1643 entity_id,
1644 Box::new(move |cx| {
1645 window_handle
1646 .update(cx, |_, cx| {
1647 if let Some(handle) = E::upgrade_from(&entity) {
1648 view.update(cx, |this, cx| on_notify(this, handle, cx))
1649 .is_ok()
1650 } else {
1651 false
1652 }
1653 })
1654 .unwrap_or(false)
1655 }),
1656 )
1657 }
1658
1659 pub fn subscribe<V2, E>(
1660 &mut self,
1661 entity: &E,
1662 mut on_event: impl FnMut(&mut V, E, &V2::Event, &mut ViewContext<'_, V>) + 'static,
1663 ) -> Subscription
1664 where
1665 V2: EventEmitter,
1666 E: Entity<V2>,
1667 {
1668 let view = self.view().downgrade();
1669 let entity_id = entity.entity_id();
1670 let handle = entity.downgrade();
1671 let window_handle = self.window.handle;
1672 self.app.event_listeners.insert(
1673 entity_id,
1674 Box::new(move |event, cx| {
1675 window_handle
1676 .update(cx, |_, cx| {
1677 if let Some(handle) = E::upgrade_from(&handle) {
1678 let event = event.downcast_ref().expect("invalid event type");
1679 view.update(cx, |this, cx| on_event(this, handle, event, cx))
1680 .is_ok()
1681 } else {
1682 false
1683 }
1684 })
1685 .unwrap_or(false)
1686 }),
1687 )
1688 }
1689
1690 pub fn on_release(
1691 &mut self,
1692 on_release: impl FnOnce(&mut V, &mut WindowContext) + 'static,
1693 ) -> Subscription {
1694 let window_handle = self.window.handle;
1695 self.app.release_listeners.insert(
1696 self.view.model.entity_id,
1697 Box::new(move |this, cx| {
1698 let this = this.downcast_mut().expect("invalid entity type");
1699 let _ = window_handle.update(cx, |_, cx| on_release(this, cx));
1700 }),
1701 )
1702 }
1703
1704 pub fn observe_release<V2, E>(
1705 &mut self,
1706 entity: &E,
1707 mut on_release: impl FnMut(&mut V, &mut V2, &mut ViewContext<'_, V>) + 'static,
1708 ) -> Subscription
1709 where
1710 V: 'static,
1711 V2: 'static,
1712 E: Entity<V2>,
1713 {
1714 let view = self.view().downgrade();
1715 let entity_id = entity.entity_id();
1716 let window_handle = self.window.handle;
1717 self.app.release_listeners.insert(
1718 entity_id,
1719 Box::new(move |entity, cx| {
1720 let entity = entity.downcast_mut().expect("invalid entity type");
1721 let _ = window_handle.update(cx, |_, cx| {
1722 view.update(cx, |this, cx| on_release(this, entity, cx))
1723 });
1724 }),
1725 )
1726 }
1727
1728 pub fn notify(&mut self) {
1729 self.window_cx.notify();
1730 self.window_cx.app.push_effect(Effect::Notify {
1731 emitter: self.view.model.entity_id,
1732 });
1733 }
1734
1735 pub fn observe_fullscreen(
1736 &mut self,
1737 mut callback: impl FnMut(&mut V, bool, &mut ViewContext<V>) + 'static,
1738 ) -> Subscription {
1739 let view = self.view.downgrade();
1740 self.window.fullscreen_listeners.insert(
1741 (),
1742 Box::new(move |fullscreen, cx| {
1743 view.update(cx, |view, cx| callback(view, fullscreen, cx))
1744 .is_ok()
1745 }),
1746 )
1747 }
1748
1749 // fn observe_window_activation(&mut self) -> Subscription {}
1750
1751 // fn observe_window_bounds(&mut self) -> Subscription {}
1752
1753 pub fn on_focus_changed(
1754 &mut self,
1755 listener: impl Fn(&mut V, &FocusEvent, &mut ViewContext<V>) + 'static,
1756 ) {
1757 let handle = self.view().downgrade();
1758 self.window.focus_listeners.push(Box::new(move |event, cx| {
1759 handle
1760 .update(cx, |view, cx| listener(view, event, cx))
1761 .log_err();
1762 }));
1763 }
1764
1765 pub fn with_key_listeners<R>(
1766 &mut self,
1767 key_listeners: impl IntoIterator<Item = (TypeId, KeyListener<V>)>,
1768 f: impl FnOnce(&mut Self) -> R,
1769 ) -> R {
1770 let old_stack_len = self.window.key_dispatch_stack.len();
1771 if !self.window.freeze_key_dispatch_stack {
1772 for (event_type, listener) in key_listeners {
1773 let handle = self.view().downgrade();
1774 let listener = Box::new(
1775 move |event: &dyn Any,
1776 context_stack: &[&DispatchContext],
1777 phase: DispatchPhase,
1778 cx: &mut WindowContext<'_>| {
1779 handle
1780 .update(cx, |view, cx| {
1781 listener(view, event, context_stack, phase, cx)
1782 })
1783 .log_err()
1784 .flatten()
1785 },
1786 );
1787 self.window
1788 .key_dispatch_stack
1789 .push(KeyDispatchStackFrame::Listener {
1790 event_type,
1791 listener,
1792 });
1793 }
1794 }
1795
1796 let result = f(self);
1797
1798 if !self.window.freeze_key_dispatch_stack {
1799 self.window.key_dispatch_stack.truncate(old_stack_len);
1800 }
1801
1802 result
1803 }
1804
1805 pub fn with_key_dispatch_context<R>(
1806 &mut self,
1807 context: DispatchContext,
1808 f: impl FnOnce(&mut Self) -> R,
1809 ) -> R {
1810 if context.is_empty() {
1811 return f(self);
1812 }
1813
1814 if !self.window.freeze_key_dispatch_stack {
1815 self.window
1816 .key_dispatch_stack
1817 .push(KeyDispatchStackFrame::Context(context));
1818 }
1819
1820 let result = f(self);
1821
1822 if !self.window.freeze_key_dispatch_stack {
1823 self.window.key_dispatch_stack.pop();
1824 }
1825
1826 result
1827 }
1828
1829 pub fn with_focus<R>(
1830 &mut self,
1831 focus_handle: FocusHandle,
1832 f: impl FnOnce(&mut Self) -> R,
1833 ) -> R {
1834 if let Some(parent_focus_id) = self.window.focus_stack.last().copied() {
1835 self.window
1836 .focus_parents_by_child
1837 .insert(focus_handle.id, parent_focus_id);
1838 }
1839 self.window.focus_stack.push(focus_handle.id);
1840
1841 if Some(focus_handle.id) == self.window.focus {
1842 self.window.freeze_key_dispatch_stack = true;
1843 }
1844
1845 let result = f(self);
1846
1847 self.window.focus_stack.pop();
1848 result
1849 }
1850
1851 pub fn spawn<Fut, R>(
1852 &mut self,
1853 f: impl FnOnce(WeakView<V>, AsyncWindowContext) -> Fut,
1854 ) -> Task<R>
1855 where
1856 R: 'static,
1857 Fut: Future<Output = R> + 'static,
1858 {
1859 let view = self.view().downgrade();
1860 self.window_cx.spawn(|cx| f(view, cx))
1861 }
1862
1863 pub fn update_global<G, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R
1864 where
1865 G: 'static,
1866 {
1867 let mut global = self.app.lease_global::<G>();
1868 let result = f(&mut global, self);
1869 self.app.end_global_lease(global);
1870 result
1871 }
1872
1873 pub fn observe_global<G: 'static>(
1874 &mut self,
1875 f: impl Fn(&mut V, &mut ViewContext<'_, V>) + 'static,
1876 ) -> Subscription {
1877 let window_handle = self.window.handle;
1878 let view = self.view().downgrade();
1879 self.global_observers.insert(
1880 TypeId::of::<G>(),
1881 Box::new(move |cx| {
1882 window_handle
1883 .update(cx, |_, cx| view.update(cx, |view, cx| f(view, cx)).is_ok())
1884 .unwrap_or(false)
1885 }),
1886 )
1887 }
1888
1889 pub fn on_mouse_event<Event: 'static>(
1890 &mut self,
1891 handler: impl Fn(&mut V, &Event, DispatchPhase, &mut ViewContext<V>) + 'static,
1892 ) {
1893 let handle = self.view();
1894 self.window_cx.on_mouse_event(move |event, phase, cx| {
1895 handle.update(cx, |view, cx| {
1896 handler(view, event, phase, cx);
1897 })
1898 });
1899 }
1900}
1901
1902impl<V> ViewContext<'_, V>
1903where
1904 V: EventEmitter,
1905 V::Event: 'static,
1906{
1907 pub fn emit(&mut self, event: V::Event) {
1908 let emitter = self.view.model.entity_id;
1909 self.app.push_effect(Effect::Emit {
1910 emitter,
1911 event: Box::new(event),
1912 });
1913 }
1914}
1915
1916impl<V> Context for ViewContext<'_, V> {
1917 type Result<U> = U;
1918
1919 fn build_model<T: 'static>(
1920 &mut self,
1921 build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
1922 ) -> Model<T> {
1923 self.window_cx.build_model(build_model)
1924 }
1925
1926 fn update_model<T: 'static, R>(
1927 &mut self,
1928 model: &Model<T>,
1929 update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
1930 ) -> R {
1931 self.window_cx.update_model(model, update)
1932 }
1933
1934 fn update_window<T, F>(&mut self, window: AnyWindowHandle, update: F) -> Result<T>
1935 where
1936 F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
1937 {
1938 self.window_cx.update_window(window, update)
1939 }
1940}
1941
1942impl<V: 'static> VisualContext for ViewContext<'_, V> {
1943 fn build_view<W: 'static>(
1944 &mut self,
1945 build_view: impl FnOnce(&mut ViewContext<'_, W>) -> W,
1946 ) -> Self::Result<View<W>> {
1947 self.window_cx.build_view(build_view)
1948 }
1949
1950 fn update_view<V2: 'static, R>(
1951 &mut self,
1952 view: &View<V2>,
1953 update: impl FnOnce(&mut V2, &mut ViewContext<'_, V2>) -> R,
1954 ) -> Self::Result<R> {
1955 self.window_cx.update_view(view, update)
1956 }
1957
1958 fn replace_root_view<W>(
1959 &mut self,
1960 build_view: impl FnOnce(&mut ViewContext<'_, W>) -> W,
1961 ) -> Self::Result<View<W>>
1962 where
1963 W: Render,
1964 {
1965 self.window_cx.replace_root_view(build_view)
1966 }
1967}
1968
1969impl<'a, V> std::ops::Deref for ViewContext<'a, V> {
1970 type Target = WindowContext<'a>;
1971
1972 fn deref(&self) -> &Self::Target {
1973 &self.window_cx
1974 }
1975}
1976
1977impl<'a, V> std::ops::DerefMut for ViewContext<'a, V> {
1978 fn deref_mut(&mut self) -> &mut Self::Target {
1979 &mut self.window_cx
1980 }
1981}
1982
1983// #[derive(Clone, Copy, Eq, PartialEq, Hash)]
1984slotmap::new_key_type! { pub struct WindowId; }
1985
1986impl WindowId {
1987 pub fn as_u64(&self) -> u64 {
1988 self.0.as_ffi()
1989 }
1990}
1991
1992#[derive(Deref, DerefMut)]
1993pub struct WindowHandle<V> {
1994 #[deref]
1995 #[deref_mut]
1996 pub(crate) any_handle: AnyWindowHandle,
1997 state_type: PhantomData<V>,
1998}
1999
2000impl<V: 'static + Render> WindowHandle<V> {
2001 pub fn new(id: WindowId) -> Self {
2002 WindowHandle {
2003 any_handle: AnyWindowHandle {
2004 id,
2005 state_type: TypeId::of::<V>(),
2006 },
2007 state_type: PhantomData,
2008 }
2009 }
2010
2011 pub fn update<C, R>(
2012 self,
2013 cx: &mut C,
2014 update: impl FnOnce(&mut V, &mut ViewContext<'_, V>) -> R,
2015 ) -> Result<R>
2016 where
2017 C: Context,
2018 {
2019 cx.update_window(self.any_handle, |root_view, cx| {
2020 let view = root_view
2021 .downcast::<V>()
2022 .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
2023 Ok(cx.update_view(&view, update))
2024 })?
2025 }
2026}
2027
2028impl<V> Copy for WindowHandle<V> {}
2029
2030impl<V> Clone for WindowHandle<V> {
2031 fn clone(&self) -> Self {
2032 WindowHandle {
2033 any_handle: self.any_handle,
2034 state_type: PhantomData,
2035 }
2036 }
2037}
2038
2039impl<V> PartialEq for WindowHandle<V> {
2040 fn eq(&self, other: &Self) -> bool {
2041 self.any_handle == other.any_handle
2042 }
2043}
2044
2045impl<V> Eq for WindowHandle<V> {}
2046
2047impl<V> Hash for WindowHandle<V> {
2048 fn hash<H: Hasher>(&self, state: &mut H) {
2049 self.any_handle.hash(state);
2050 }
2051}
2052
2053impl<V: 'static> Into<AnyWindowHandle> for WindowHandle<V> {
2054 fn into(self) -> AnyWindowHandle {
2055 self.any_handle
2056 }
2057}
2058
2059#[derive(Copy, Clone, PartialEq, Eq, Hash)]
2060pub struct AnyWindowHandle {
2061 pub(crate) id: WindowId,
2062 state_type: TypeId,
2063}
2064
2065impl AnyWindowHandle {
2066 pub fn window_id(&self) -> WindowId {
2067 self.id
2068 }
2069
2070 pub fn downcast<T: 'static>(&self) -> Option<WindowHandle<T>> {
2071 if TypeId::of::<T>() == self.state_type {
2072 Some(WindowHandle {
2073 any_handle: *self,
2074 state_type: PhantomData,
2075 })
2076 } else {
2077 None
2078 }
2079 }
2080
2081 pub fn update<C, R>(
2082 self,
2083 cx: &mut C,
2084 update: impl FnOnce(AnyView, &mut WindowContext<'_>) -> R,
2085 ) -> Result<R>
2086 where
2087 C: Context,
2088 {
2089 cx.update_window(self, update)
2090 }
2091}
2092
2093#[cfg(any(test, feature = "test-support"))]
2094impl From<SmallVec<[u32; 16]>> for StackingOrder {
2095 fn from(small_vec: SmallVec<[u32; 16]>) -> Self {
2096 StackingOrder(small_vec)
2097 }
2098}
2099
2100#[derive(Clone, Debug, Eq, PartialEq, Hash)]
2101pub enum ElementId {
2102 View(EntityId),
2103 Number(usize),
2104 Name(SharedString),
2105 FocusHandle(FocusId),
2106}
2107
2108impl From<EntityId> for ElementId {
2109 fn from(id: EntityId) -> Self {
2110 ElementId::View(id)
2111 }
2112}
2113
2114impl From<usize> for ElementId {
2115 fn from(id: usize) -> Self {
2116 ElementId::Number(id)
2117 }
2118}
2119
2120impl From<i32> for ElementId {
2121 fn from(id: i32) -> Self {
2122 Self::Number(id as usize)
2123 }
2124}
2125
2126impl From<SharedString> for ElementId {
2127 fn from(name: SharedString) -> Self {
2128 ElementId::Name(name)
2129 }
2130}
2131
2132impl From<&'static str> for ElementId {
2133 fn from(name: &'static str) -> Self {
2134 ElementId::Name(name.into())
2135 }
2136}
2137
2138impl<'a> From<&'a FocusHandle> for ElementId {
2139 fn from(handle: &'a FocusHandle) -> Self {
2140 ElementId::FocusHandle(handle.id)
2141 }
2142}