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gpui/elements/
div.rs

1//! Div is the central, reusable element that most GPUI trees will be built from.
2//! It functions as a container for other elements, and provides a number of
3//! useful features for laying out and styling its children as well as binding
4//! mouse events and action handlers. It is meant to be similar to the HTML `<div>`
5//! element, but for GPUI.
6//!
7//! # Build your own div
8//!
9//! GPUI does not directly provide APIs for stateful, multi step events like `click`
10//! and `drag`. We want GPUI users to be able to build their own abstractions for
11//! their own needs. However, as a UI framework, we're also obliged to provide some
12//! building blocks to make the process of building your own elements easier.
13//! For this we have the [`Interactivity`] and the [`StyleRefinement`] structs, as well
14//! as several associated traits. Together, these provide the full suite of Dom-like events
15//! and Tailwind-like styling that you can use to build your own custom elements. Div is
16//! constructed by combining these two systems into an all-in-one element.
17
18use crate::{
19    Action, AnyDrag, AnyElement, AnyTooltip, AnyView, App, Bounds, ClickEvent, DispatchPhase,
20    Display, Element, ElementId, Entity, EntityId, ExternalDragPayload, ExternalDragPayloadSource,
21    FocusHandle, Global, GlobalElementId, Hitbox, HitboxBehavior, HitboxId, InspectorElementId,
22    IntoElement, IsZero, KeyContext, KeyDownEvent, KeyUpEvent, KeyboardButton, KeyboardClickEvent,
23    LayoutId, ModifiersChangedEvent, MouseButton, MouseClickEvent, MouseDownEvent, MouseExitEvent,
24    MouseMoveEvent, MousePressureEvent, MouseUpEvent, OngoingScroll, Overflow, ParentElement,
25    PinchEvent, Pixels, Point, Render, ScrollWheelEvent, SharedString, Size, Style,
26    StyleRefinement, Styled, Task, TooltipId, Visibility, Window, WindowControlArea, point, px,
27    size,
28};
29use collections::HashMap;
30use gpui_util::ResultExt;
31use refineable::Refineable;
32use smallvec::SmallVec;
33use stacksafe::{StackSafe, stacksafe};
34use std::{
35    any::{Any, TypeId},
36    cell::RefCell,
37    cmp::Ordering,
38    fmt::Debug,
39    marker::PhantomData,
40    mem,
41    rc::Rc,
42    sync::Arc,
43    time::Duration,
44};
45
46use super::ImageCacheProvider;
47
48const DRAG_THRESHOLD: f64 = 2.;
49const DEFAULT_TOOLTIP_SHOW_DELAY: Duration = Duration::from_millis(500);
50const HOVERABLE_TOOLTIP_HIDE_DELAY: Duration = Duration::from_millis(500);
51
52/// The styling information for a given group.
53pub struct GroupStyle {
54    /// The identifier for this group.
55    pub group: SharedString,
56
57    /// The specific style refinement that this group would apply
58    /// to its children.
59    pub style: Box<StyleRefinement>,
60}
61
62/// An event for when a drag is moving over this element, with the given state type.
63pub struct DragMoveEvent<T> {
64    /// The mouse move event that triggered this drag move event.
65    pub event: MouseMoveEvent,
66
67    /// The bounds of this element.
68    pub bounds: Bounds<Pixels>,
69    drag: PhantomData<T>,
70    dragged_item: Arc<dyn Any>,
71}
72
73impl<T: 'static> DragMoveEvent<T> {
74    /// Returns the drag state for this event.
75    pub fn drag<'b>(&self, cx: &'b App) -> &'b T {
76        cx.active_drag
77            .as_ref()
78            .and_then(|drag| drag.value.downcast_ref::<T>())
79            .expect("DragMoveEvent is only valid when the stored active drag is of the same type.")
80    }
81
82    /// An item that is about to be dropped.
83    pub fn dragged_item(&self) -> &dyn Any {
84        self.dragged_item.as_ref()
85    }
86}
87
88impl Interactivity {
89    /// Create an `Interactivity`, capturing the caller location in debug mode.
90    #[cfg(any(feature = "inspector", debug_assertions))]
91    #[track_caller]
92    pub fn new() -> Interactivity {
93        Interactivity {
94            source_location: Some(core::panic::Location::caller()),
95            ..Default::default()
96        }
97    }
98
99    /// Create an `Interactivity`, capturing the caller location in debug mode.
100    #[cfg(not(any(feature = "inspector", debug_assertions)))]
101    pub fn new() -> Interactivity {
102        Interactivity::default()
103    }
104
105    /// Gets the source location of construction. Returns `None` when not in debug mode.
106    pub fn source_location(&self) -> Option<&'static std::panic::Location<'static>> {
107        #[cfg(any(feature = "inspector", debug_assertions))]
108        {
109            self.source_location
110        }
111
112        #[cfg(not(any(feature = "inspector", debug_assertions)))]
113        {
114            None
115        }
116    }
117
118    /// Bind the given callback to the mouse down event for the given mouse button, during the bubble phase.
119    /// The imperative API equivalent of [`InteractiveElement::on_mouse_down`].
120    ///
121    /// See [`Context::listener`](crate::Context::listener) to get access to the view state from this callback.
122    pub fn on_mouse_down(
123        &mut self,
124        button: MouseButton,
125        listener: impl Fn(&MouseDownEvent, &mut Window, &mut App) + 'static,
126    ) {
127        self.mouse_down_listeners
128            .push(Box::new(move |event, phase, hitbox, window, cx| {
129                if phase == DispatchPhase::Bubble
130                    && event.button == button
131                    && hitbox.is_hovered(window)
132                {
133                    (listener)(event, window, cx)
134                }
135            }));
136    }
137
138    /// Bind the given callback to the mouse down event for any button, during the capture phase.
139    /// The imperative API equivalent of [`InteractiveElement::capture_any_mouse_down`].
140    ///
141    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
142    pub fn capture_any_mouse_down(
143        &mut self,
144        listener: impl Fn(&MouseDownEvent, &mut Window, &mut App) + 'static,
145    ) {
146        self.mouse_down_listeners
147            .push(Box::new(move |event, phase, hitbox, window, cx| {
148                if phase == DispatchPhase::Capture && hitbox.is_hovered(window) {
149                    (listener)(event, window, cx)
150                }
151            }));
152    }
153
154    /// Bind the given callback to the mouse down event for any button, during the bubble phase.
155    /// The imperative API equivalent to [`InteractiveElement::on_any_mouse_down`].
156    ///
157    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
158    pub fn on_any_mouse_down(
159        &mut self,
160        listener: impl Fn(&MouseDownEvent, &mut Window, &mut App) + 'static,
161    ) {
162        self.mouse_down_listeners
163            .push(Box::new(move |event, phase, hitbox, window, cx| {
164                if phase == DispatchPhase::Bubble && hitbox.is_hovered(window) {
165                    (listener)(event, window, cx)
166                }
167            }));
168    }
169
170    /// Bind the given callback to the mouse pressure event, during the bubble phase
171    /// the imperative API equivalent to [`InteractiveElement::on_mouse_pressure`].
172    ///
173    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
174    pub fn on_mouse_pressure(
175        &mut self,
176        listener: impl Fn(&MousePressureEvent, &mut Window, &mut App) + 'static,
177    ) {
178        self.mouse_pressure_listeners
179            .push(Box::new(move |event, phase, hitbox, window, cx| {
180                if phase == DispatchPhase::Bubble && hitbox.is_hovered(window) {
181                    (listener)(event, window, cx)
182                }
183            }));
184    }
185
186    /// Bind the given callback to the mouse pressure event, during the capture phase
187    /// the imperative API equivalent to [`InteractiveElement::on_mouse_pressure`].
188    ///
189    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
190    pub fn capture_mouse_pressure(
191        &mut self,
192        listener: impl Fn(&MousePressureEvent, &mut Window, &mut App) + 'static,
193    ) {
194        self.mouse_pressure_listeners
195            .push(Box::new(move |event, phase, hitbox, window, cx| {
196                if phase == DispatchPhase::Capture && hitbox.is_hovered(window) {
197                    (listener)(event, window, cx)
198                }
199            }));
200    }
201
202    /// Bind the given callback to the mouse up event for the given button, during the bubble phase.
203    /// The imperative API equivalent to [`InteractiveElement::on_mouse_up`].
204    ///
205    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
206    pub fn on_mouse_up(
207        &mut self,
208        button: MouseButton,
209        listener: impl Fn(&MouseUpEvent, &mut Window, &mut App) + 'static,
210    ) {
211        self.mouse_up_listeners
212            .push(Box::new(move |event, phase, hitbox, window, cx| {
213                if phase == DispatchPhase::Bubble
214                    && event.button == button
215                    && hitbox.is_hovered(window)
216                {
217                    (listener)(event, window, cx)
218                }
219            }));
220    }
221
222    /// Bind the given callback to the mouse up event for any button, during the capture phase.
223    /// The imperative API equivalent to [`InteractiveElement::capture_any_mouse_up`].
224    ///
225    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
226    pub fn capture_any_mouse_up(
227        &mut self,
228        listener: impl Fn(&MouseUpEvent, &mut Window, &mut App) + 'static,
229    ) {
230        self.mouse_up_listeners
231            .push(Box::new(move |event, phase, hitbox, window, cx| {
232                if phase == DispatchPhase::Capture && hitbox.is_hovered(window) {
233                    (listener)(event, window, cx)
234                }
235            }));
236    }
237
238    /// Bind the given callback to the mouse up event for any button, during the bubble phase.
239    /// The imperative API equivalent to [`Interactivity::on_any_mouse_up`].
240    ///
241    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
242    pub fn on_any_mouse_up(
243        &mut self,
244        listener: impl Fn(&MouseUpEvent, &mut Window, &mut App) + 'static,
245    ) {
246        self.mouse_up_listeners
247            .push(Box::new(move |event, phase, hitbox, window, cx| {
248                if phase == DispatchPhase::Bubble && hitbox.is_hovered(window) {
249                    (listener)(event, window, cx)
250                }
251            }));
252    }
253
254    /// Bind the given callback to the mouse down event, on any button, during the capture phase,
255    /// when the mouse is outside of the bounds of this element.
256    /// The imperative API equivalent to [`InteractiveElement::on_mouse_down_out`].
257    ///
258    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
259    pub fn on_mouse_down_out(
260        &mut self,
261        listener: impl Fn(&MouseDownEvent, &mut Window, &mut App) + 'static,
262    ) {
263        self.mouse_down_listeners
264            .push(Box::new(move |event, phase, hitbox, window, cx| {
265                if phase == DispatchPhase::Capture
266                    && !window.has_active_prompt()
267                    && !hitbox.contains(&window.mouse_position())
268                {
269                    (listener)(event, window, cx)
270                }
271            }));
272    }
273
274    /// Bind the given callback to the mouse down event - for all mouse up events,
275    /// regardless of dispatch phase, mouse button, or whether the mouse is
276    /// inside or outside the bounds of the element.
277    /// The imperative API equivalent to [`InteractiveElement::on_mouse_down_all`].
278    ///
279    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
280    pub fn on_mouse_down_all(
281        &mut self,
282        listener: impl Fn(&MouseDownEvent, DispatchPhase, &Hitbox, &mut Window, &mut App) + 'static,
283    ) {
284        self.mouse_down_listeners.push(Box::new(listener));
285    }
286
287    /// Bind the given callback to the mouse up event, for the given button, during the capture phase,
288    /// when the mouse is outside of the bounds of this element.
289    /// The imperative API equivalent to [`InteractiveElement::on_mouse_up_out`].
290    ///
291    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
292    pub fn on_mouse_up_out(
293        &mut self,
294        button: MouseButton,
295        listener: impl Fn(&MouseUpEvent, &mut Window, &mut App) + 'static,
296    ) {
297        self.mouse_up_listeners
298            .push(Box::new(move |event, phase, hitbox, window, cx| {
299                if phase == DispatchPhase::Capture
300                    && event.button == button
301                    && !hitbox.is_hovered(window)
302                {
303                    (listener)(event, window, cx);
304                }
305            }));
306    }
307
308    /// Bind the given callback to the mouse up event - for all mouse up events,
309    /// regardless of dispatch phase, mouse button, or whether the mouse is
310    /// inside or outside the bounds of the element.
311    /// The imperative API equivalent to [`InteractiveElement::on_mouse_up_all`].
312    ///
313    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
314    pub fn on_mouse_up_all(
315        &mut self,
316        listener: impl Fn(&MouseUpEvent, DispatchPhase, &Hitbox, &mut Window, &mut App) + 'static,
317    ) {
318        self.mouse_up_listeners.push(Box::new(listener));
319    }
320
321    /// Bind the given callback to the mouse move event, during the bubble phase.
322    /// The imperative API equivalent to [`InteractiveElement::on_mouse_move`].
323    ///
324    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
325    pub fn on_mouse_move(
326        &mut self,
327        listener: impl Fn(&MouseMoveEvent, &mut Window, &mut App) + 'static,
328    ) {
329        self.mouse_move_listeners
330            .push(Box::new(move |event, phase, hitbox, window, cx| {
331                if phase == DispatchPhase::Bubble && hitbox.is_hovered(window) {
332                    (listener)(event, window, cx);
333                }
334            }));
335    }
336
337    /// Bind the given callback to the mouse exit event, during the bubble phase.
338    /// The imperative API equivalent to [`InteractiveElement::on_mouse_exit`].
339    ///
340    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
341    pub fn on_mouse_exit(
342        &mut self,
343        listener: impl Fn(&MouseExitEvent, &mut Window, &mut App) + 'static,
344    ) {
345        self.mouse_exit_listeners
346            .push(Box::new(move |event, phase, hitbox, window, cx| {
347                if phase == DispatchPhase::Bubble && hitbox.is_hovered(window) {
348                    (listener)(event, window, cx);
349                }
350            }));
351    }
352
353    /// Bind the given callback to the mouse drag event of the given type. Note that this
354    /// will be called for all move events, inside or outside of this element, as long as the
355    /// drag was started with this element under the mouse. Useful for implementing draggable
356    /// UIs that don't conform to a drag and drop style interaction, like resizing.
357    /// The imperative API equivalent to [`InteractiveElement::on_drag_move`].
358    ///
359    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
360    pub fn on_drag_move<T>(
361        &mut self,
362        listener: impl Fn(&DragMoveEvent<T>, &mut Window, &mut App) + 'static,
363    ) where
364        T: 'static,
365    {
366        self.mouse_move_listeners
367            .push(Box::new(move |event, phase, hitbox, window, cx| {
368                if phase == DispatchPhase::Capture
369                    && let Some(drag) = &cx.active_drag
370                    && drag.value.as_ref().type_id() == TypeId::of::<T>()
371                {
372                    (listener)(
373                        &DragMoveEvent {
374                            event: event.clone(),
375                            bounds: hitbox.bounds,
376                            drag: PhantomData,
377                            dragged_item: Arc::clone(&drag.value),
378                        },
379                        window,
380                        cx,
381                    );
382                }
383            }));
384    }
385
386    /// Bind the given callback to scroll wheel events during the bubble phase.
387    /// The imperative API equivalent to [`InteractiveElement::on_scroll_wheel`].
388    ///
389    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
390    pub fn on_scroll_wheel(
391        &mut self,
392        listener: impl Fn(&ScrollWheelEvent, &mut Window, &mut App) + 'static,
393    ) {
394        self.scroll_wheel_listeners
395            .push(Box::new(move |event, phase, hitbox, window, cx| {
396                if phase == DispatchPhase::Bubble && hitbox.should_handle_scroll(window) {
397                    (listener)(event, window, cx);
398                }
399            }));
400    }
401
402    /// Bind the given callback to pinch gesture events during the bubble phase.
403    ///
404    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
405    pub fn on_pinch(&mut self, listener: impl Fn(&PinchEvent, &mut Window, &mut App) + 'static) {
406        self.pinch_listeners
407            .push(Box::new(move |event, phase, hitbox, window, cx| {
408                if phase == DispatchPhase::Bubble && hitbox.is_hovered(window) {
409                    (listener)(event, window, cx);
410                }
411            }));
412    }
413
414    /// Bind the given callback to pinch gesture events during the capture phase.
415    ///
416    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
417    pub fn capture_pinch(
418        &mut self,
419        listener: impl Fn(&PinchEvent, &mut Window, &mut App) + 'static,
420    ) {
421        self.pinch_listeners
422            .push(Box::new(move |event, phase, _hitbox, window, cx| {
423                if phase == DispatchPhase::Capture {
424                    (listener)(event, window, cx);
425                } else {
426                    cx.propagate();
427                }
428            }));
429    }
430
431    /// Bind the given callback to an action dispatch during the capture phase.
432    /// The imperative API equivalent to [`InteractiveElement::capture_action`].
433    ///
434    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
435    pub fn capture_action<A: Action>(
436        &mut self,
437        listener: impl Fn(&A, &mut Window, &mut App) + 'static,
438    ) {
439        self.action_listeners.push((
440            TypeId::of::<A>(),
441            Box::new(move |action, phase, window, cx| {
442                let action = action.downcast_ref().unwrap();
443                if phase == DispatchPhase::Capture {
444                    (listener)(action, window, cx)
445                } else {
446                    cx.propagate();
447                }
448            }),
449        ));
450    }
451
452    /// Bind the given callback to an action dispatch during the bubble phase.
453    /// The imperative API equivalent to [`InteractiveElement::on_action`].
454    ///
455    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
456    #[track_caller]
457    pub fn on_action<A: Action>(&mut self, listener: impl Fn(&A, &mut Window, &mut App) + 'static) {
458        self.action_listeners.push((
459            TypeId::of::<A>(),
460            Box::new(move |action, phase, window, cx| {
461                let action = action.downcast_ref().unwrap();
462                if phase == DispatchPhase::Bubble {
463                    (listener)(action, window, cx)
464                }
465            }),
466        ));
467    }
468
469    /// Bind the given callback to an action dispatch, based on a dynamic action parameter
470    /// instead of a type parameter. Useful for component libraries that want to expose
471    /// action bindings to their users.
472    /// The imperative API equivalent to [`InteractiveElement::on_boxed_action`].
473    ///
474    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
475    pub fn on_boxed_action(
476        &mut self,
477        action: &dyn Action,
478        listener: impl Fn(&dyn Action, &mut Window, &mut App) + 'static,
479    ) {
480        let action = action.boxed_clone();
481        self.action_listeners.push((
482            (*action).type_id(),
483            Box::new(move |_, phase, window, cx| {
484                if phase == DispatchPhase::Bubble {
485                    (listener)(&*action, window, cx)
486                }
487            }),
488        ));
489    }
490
491    /// Bind the given callback to key down events during the bubble phase.
492    /// The imperative API equivalent to [`InteractiveElement::on_key_down`].
493    ///
494    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
495    pub fn on_key_down(
496        &mut self,
497        listener: impl Fn(&KeyDownEvent, &mut Window, &mut App) + 'static,
498    ) {
499        self.key_down_listeners
500            .push(Box::new(move |event, phase, window, cx| {
501                if phase == DispatchPhase::Bubble {
502                    (listener)(event, window, cx)
503                }
504            }));
505    }
506
507    /// Bind the given callback to key down events during the capture phase.
508    /// The imperative API equivalent to [`InteractiveElement::capture_key_down`].
509    ///
510    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
511    pub fn capture_key_down(
512        &mut self,
513        listener: impl Fn(&KeyDownEvent, &mut Window, &mut App) + 'static,
514    ) {
515        self.key_down_listeners
516            .push(Box::new(move |event, phase, window, cx| {
517                if phase == DispatchPhase::Capture {
518                    listener(event, window, cx)
519                }
520            }));
521    }
522
523    /// Bind the given callback to key up events during the bubble phase.
524    /// The imperative API equivalent to [`InteractiveElement::on_key_up`].
525    ///
526    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
527    pub fn on_key_up(&mut self, listener: impl Fn(&KeyUpEvent, &mut Window, &mut App) + 'static) {
528        self.key_up_listeners
529            .push(Box::new(move |event, phase, window, cx| {
530                if phase == DispatchPhase::Bubble {
531                    listener(event, window, cx)
532                }
533            }));
534    }
535
536    /// Bind the given callback to key up events during the capture phase.
537    /// The imperative API equivalent to [`InteractiveElement::on_key_up`].
538    ///
539    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
540    pub fn capture_key_up(
541        &mut self,
542        listener: impl Fn(&KeyUpEvent, &mut Window, &mut App) + 'static,
543    ) {
544        self.key_up_listeners
545            .push(Box::new(move |event, phase, window, cx| {
546                if phase == DispatchPhase::Capture {
547                    listener(event, window, cx)
548                }
549            }));
550    }
551
552    /// Bind the given callback to modifiers changing events.
553    /// The imperative API equivalent to [`InteractiveElement::on_modifiers_changed`].
554    ///
555    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
556    pub fn on_modifiers_changed(
557        &mut self,
558        listener: impl Fn(&ModifiersChangedEvent, &mut Window, &mut App) + 'static,
559    ) {
560        self.modifiers_changed_listeners
561            .push(Box::new(move |event, window, cx| {
562                listener(event, window, cx)
563            }));
564    }
565
566    /// Bind the given callback to drop events of the given type, whether or not the drag started on this element.
567    /// The imperative API equivalent to [`InteractiveElement::on_drop`].
568    ///
569    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
570    pub fn on_drop<T: 'static>(&mut self, listener: impl Fn(&T, &mut Window, &mut App) + 'static) {
571        self.drop_listeners.push((
572            TypeId::of::<T>(),
573            Box::new(move |dragged_value, window, cx| {
574                listener(dragged_value.downcast_ref().unwrap(), window, cx);
575            }),
576        ));
577    }
578
579    /// Use the given predicate to determine whether or not a drop event should be dispatched to this element.
580    /// The imperative API equivalent to [`InteractiveElement::can_drop`].
581    pub fn can_drop(
582        &mut self,
583        predicate: impl Fn(&dyn Any, &mut Window, &mut App) -> bool + 'static,
584    ) {
585        self.can_drop_predicate = Some(Box::new(predicate));
586    }
587
588    /// Bind the given callback to click events of this element.
589    /// The imperative API equivalent to [`StatefulInteractiveElement::on_click`].
590    ///
591    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
592    pub fn on_click(&mut self, listener: impl Fn(&ClickEvent, &mut Window, &mut App) + 'static)
593    where
594        Self: Sized,
595    {
596        self.click_listeners.push(Rc::new(move |event, window, cx| {
597            listener(event, window, cx)
598        }));
599    }
600
601    /// Bind the given callback to non-primary click events of this element.
602    /// The imperative API equivalent to [`StatefulInteractiveElement::on_aux_click`].
603    ///
604    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
605    pub fn on_aux_click(&mut self, listener: impl Fn(&ClickEvent, &mut Window, &mut App) + 'static)
606    where
607        Self: Sized,
608    {
609        self.aux_click_listeners
610            .push(Rc::new(move |event, window, cx| {
611                listener(event, window, cx)
612            }));
613    }
614
615    /// On drag initiation, this callback will be used to create a new view to render the dragged value for a
616    /// drag and drop operation. This API should also be used as the equivalent of 'on drag start' with
617    /// the [`Self::on_drag_move`] API.
618    /// The imperative API equivalent to [`StatefulInteractiveElement::on_drag`].
619    ///
620    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
621    pub fn on_drag<T, W>(
622        &mut self,
623        value: T,
624        constructor: impl Fn(&T, Point<Pixels>, &mut Window, &mut App) -> Entity<W> + 'static,
625    ) where
626        Self: Sized,
627        T: 'static,
628        W: 'static + Render,
629    {
630        debug_assert!(
631            self.drag_listener.is_none(),
632            "calling on_drag more than once on the same element is not supported"
633        );
634        self.drag_listener = Some(DragListener {
635            value: Arc::new(value),
636            render: Box::new(move |value, offset, window, cx| {
637                constructor(value.downcast_ref().unwrap(), offset, window, cx).into()
638            }),
639            external_payload: None,
640        });
641    }
642
643    /// Registers a callback resolving a payload to offer the platform if a drag started by this
644    /// element leaves the window. It is invoked at most once per drag gesture, when the pointer
645    /// exits the viewport. Must be called after [`Self::on_drag`], with the same dragged value
646    /// type `T`.
647    pub fn external_drag_payload<T>(
648        &mut self,
649        resolver: impl Fn(&T, &mut Window, &mut App) -> Option<ExternalDragPayload> + 'static,
650    ) where
651        Self: Sized,
652        T: 'static,
653    {
654        let Some(drag_listener) = self.drag_listener.as_mut() else {
655            debug_assert!(false, "external_drag_payload must be called after on_drag");
656            return;
657        };
658        debug_assert!(
659            drag_listener.value.as_ref().type_id() == TypeId::of::<T>(),
660            "external_drag_payload must use the same dragged value type as on_drag"
661        );
662        debug_assert!(
663            drag_listener.external_payload.is_none(),
664            "calling external_drag_payload more than once on the same element is not supported"
665        );
666        drag_listener.external_payload = Some(Box::new(move |value, window, cx| {
667            resolver(value.downcast_ref::<T>()?, window, cx)
668        }));
669    }
670
671    /// Bind the given callback on the hover start and end events of this element. Note that the boolean
672    /// passed to the callback is true when the hover starts and false when it ends.
673    /// The imperative API equivalent to [`StatefulInteractiveElement::on_hover`].
674    ///
675    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
676    pub fn on_hover(&mut self, listener: impl Fn(&bool, &mut Window, &mut App) + 'static)
677    where
678        Self: Sized,
679    {
680        debug_assert!(
681            self.hover_listener.is_none(),
682            "calling on_hover more than once on the same element is not supported"
683        );
684        self.hover_listener = Some(Box::new(listener));
685    }
686
687    /// Use the given callback to construct a new tooltip view when the mouse hovers over this element.
688    /// The imperative API equivalent to [`StatefulInteractiveElement::tooltip`].
689    pub fn tooltip(&mut self, build_tooltip: impl Fn(&mut Window, &mut App) -> AnyView + 'static)
690    where
691        Self: Sized,
692    {
693        debug_assert!(
694            self.tooltip_builder.is_none(),
695            "calling tooltip more than once on the same element is not supported"
696        );
697        self.tooltip_builder = Some(TooltipBuilder {
698            build: Rc::new(build_tooltip),
699            hoverable: false,
700        });
701    }
702
703    /// Use the given callback to construct a new tooltip view when the mouse hovers over this element.
704    /// The tooltip itself is also hoverable and won't disappear when the user moves the mouse into
705    /// the tooltip. The imperative API equivalent to [`StatefulInteractiveElement::hoverable_tooltip`].
706    pub fn hoverable_tooltip(
707        &mut self,
708        build_tooltip: impl Fn(&mut Window, &mut App) -> AnyView + 'static,
709    ) where
710        Self: Sized,
711    {
712        debug_assert!(
713            self.tooltip_builder.is_none(),
714            "calling tooltip more than once on the same element is not supported"
715        );
716        self.tooltip_builder = Some(TooltipBuilder {
717            build: Rc::new(build_tooltip),
718            hoverable: true,
719        });
720    }
721
722    /// Set the delay before this element's tooltip is shown.
723    /// The imperative API equivalent to [`StatefulInteractiveElement::tooltip_show_delay`].
724    pub fn tooltip_show_delay(&mut self, delay: Duration) {
725        self.tooltip_show_delay = Some(delay);
726    }
727
728    /// Block the mouse from all interactions with elements behind this element's hitbox. Typically
729    /// `block_mouse_except_scroll` should be preferred.
730    ///
731    /// The imperative API equivalent to [`InteractiveElement::occlude`]
732    pub fn occlude_mouse(&mut self) {
733        self.hitbox_behavior = HitboxBehavior::BlockMouse;
734    }
735
736    /// Set the bounds of this element as a window control area for the platform window.
737    /// The imperative API equivalent to [`InteractiveElement::window_control_area`]
738    pub fn window_control_area(&mut self, area: WindowControlArea) {
739        self.window_control = Some(area);
740    }
741
742    /// Block non-scroll mouse interactions with elements behind this element's hitbox.
743    /// The imperative API equivalent to [`InteractiveElement::block_mouse_except_scroll`].
744    ///
745    /// See [`Hitbox::is_hovered`] for details.
746    pub fn block_mouse_except_scroll(&mut self) {
747        self.hitbox_behavior = HitboxBehavior::BlockMouseExceptScroll;
748    }
749
750    fn has_pinch_listeners(&self) -> bool {
751        !self.pinch_listeners.is_empty()
752    }
753}
754
755/// A trait for elements that want to use the standard GPUI event handlers that don't
756/// require any state.
757pub trait InteractiveElement: Sized {
758    /// Retrieve the interactivity state associated with this element
759    fn interactivity(&mut self) -> &mut Interactivity;
760
761    /// Assign this element to a group of elements that can be styled together
762    fn group(mut self, group: impl Into<SharedString>) -> Self {
763        self.interactivity().group = Some(group.into());
764        self
765    }
766
767    /// Assign this element an ID, so that it can be used with interactivity
768    fn id(mut self, id: impl Into<ElementId>) -> Stateful<Self> {
769        self.interactivity().element_id = Some(id.into());
770
771        Stateful { element: self }
772    }
773
774    /// Track the focus state of the given focus handle on this element.
775    /// If the focus handle is focused by the application, this element will
776    /// apply its focused styles.
777    fn track_focus(mut self, focus_handle: &FocusHandle) -> Self {
778        self.interactivity().focusable = true;
779        self.interactivity().tracked_focus_handle = Some(focus_handle.clone());
780        self
781    }
782
783    /// Set whether this element is a tab stop.
784    ///
785    /// When false, the element remains in tab-index order but cannot be reached via keyboard navigation.
786    /// Useful for container elements: focus the container, then call `window.focus_next(cx)` to focus
787    /// the first tab stop inside it while having the container element itself be unreachable via the keyboard.
788    /// Should only be used with `tab_index`.
789    fn tab_stop(mut self, tab_stop: bool) -> Self {
790        self.interactivity().tab_stop = tab_stop;
791        self
792    }
793
794    /// Set index of the tab stop order, and set this node as a tab stop.
795    /// This will default the element to being a tab stop. See [`Self::tab_stop`] for more information.
796    /// This should only be used in conjunction with `tab_group`
797    /// in order to not interfere with the tab index of other elements.
798    fn tab_index(mut self, index: isize) -> Self {
799        self.interactivity().focusable = true;
800        self.interactivity().tab_index = Some(index);
801        self.interactivity().tab_stop = true;
802        self
803    }
804
805    /// Designate this div as a "tab group". Tab groups have their own location in the tab-index order,
806    /// but for children of the tab group, the tab index is reset to 0. This can be useful for swapping
807    /// the order of tab stops within the group, without having to renumber all the tab stops in the whole
808    /// application.
809    fn tab_group(mut self) -> Self {
810        self.interactivity().tab_group = true;
811        if self.interactivity().tab_index.is_none() {
812            self.interactivity().tab_index = Some(0);
813        }
814        self
815    }
816
817    /// Set the keymap context for this element. This will be used to determine
818    /// which action to dispatch from the keymap.
819    fn key_context<C, E>(mut self, key_context: C) -> Self
820    where
821        C: TryInto<KeyContext, Error = E>,
822        E: std::fmt::Display,
823    {
824        if let Some(key_context) = key_context.try_into().log_err() {
825            self.interactivity().key_context = Some(key_context);
826        }
827        self
828    }
829
830    /// Apply the given style to this element when the mouse hovers over it
831    fn hover(mut self, f: impl FnOnce(StyleRefinement) -> StyleRefinement) -> Self {
832        debug_assert!(
833            self.interactivity().hover_style.is_none(),
834            "hover style already set"
835        );
836        self.interactivity().hover_style = Some(Box::new(f(StyleRefinement::default())));
837        self
838    }
839
840    /// Apply the given style to this element when the mouse hovers over a group member
841    fn group_hover(
842        mut self,
843        group_name: impl Into<SharedString>,
844        f: impl FnOnce(StyleRefinement) -> StyleRefinement,
845    ) -> Self {
846        self.interactivity().group_hover_style = Some(GroupStyle {
847            group: group_name.into(),
848            style: Box::new(f(StyleRefinement::default())),
849        });
850        self
851    }
852
853    /// Bind the given callback to the mouse down event for the given mouse button.
854    /// The fluent API equivalent to [`Interactivity::on_mouse_down`].
855    ///
856    /// See [`Context::listener`](crate::Context::listener) to get access to the view state from this callback.
857    fn on_mouse_down(
858        mut self,
859        button: MouseButton,
860        listener: impl Fn(&MouseDownEvent, &mut Window, &mut App) + 'static,
861    ) -> Self {
862        self.interactivity().on_mouse_down(button, listener);
863        self
864    }
865
866    #[cfg(any(test, feature = "test-support"))]
867    /// Set a key that can be used to look up this element's bounds
868    /// in the [`crate::VisualTestContext::debug_bounds`] map
869    /// This is a noop in release builds
870    fn debug_selector(mut self, f: impl FnOnce() -> String) -> Self {
871        self.interactivity().debug_selector = Some(f());
872        self
873    }
874
875    #[cfg(not(any(test, feature = "test-support")))]
876    /// Set a key that can be used to look up this element's bounds
877    /// in the [`crate::VisualTestContext::debug_bounds`] map
878    /// This is a noop in release builds
879    #[inline]
880    fn debug_selector(self, _: impl FnOnce() -> String) -> Self {
881        self
882    }
883
884    /// Bind the given callback to the mouse down event for any button, during the capture phase.
885    /// The fluent API equivalent to [`Interactivity::capture_any_mouse_down`].
886    ///
887    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
888    fn capture_any_mouse_down(
889        mut self,
890        listener: impl Fn(&MouseDownEvent, &mut Window, &mut App) + 'static,
891    ) -> Self {
892        self.interactivity().capture_any_mouse_down(listener);
893        self
894    }
895
896    /// Bind the given callback to the mouse down event for any button, during the capture phase.
897    /// The fluent API equivalent to [`Interactivity::on_any_mouse_down`].
898    ///
899    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
900    fn on_any_mouse_down(
901        mut self,
902        listener: impl Fn(&MouseDownEvent, &mut Window, &mut App) + 'static,
903    ) -> Self {
904        self.interactivity().on_any_mouse_down(listener);
905        self
906    }
907
908    /// Bind the given callback to the mouse up event for the given button, during the bubble phase.
909    /// The fluent API equivalent to [`Interactivity::on_mouse_up`].
910    ///
911    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
912    fn on_mouse_up(
913        mut self,
914        button: MouseButton,
915        listener: impl Fn(&MouseUpEvent, &mut Window, &mut App) + 'static,
916    ) -> Self {
917        self.interactivity().on_mouse_up(button, listener);
918        self
919    }
920
921    /// Bind the given callback to the mouse up event for any button, during the capture phase.
922    /// The fluent API equivalent to [`Interactivity::capture_any_mouse_up`].
923    ///
924    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
925    fn capture_any_mouse_up(
926        mut self,
927        listener: impl Fn(&MouseUpEvent, &mut Window, &mut App) + 'static,
928    ) -> Self {
929        self.interactivity().capture_any_mouse_up(listener);
930        self
931    }
932
933    /// Bind the given callback to the mouse pressure event, during the bubble phase
934    /// the fluent API equivalent to [`Interactivity::on_mouse_pressure`]
935    ///
936    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
937    fn on_mouse_pressure(
938        mut self,
939        listener: impl Fn(&MousePressureEvent, &mut Window, &mut App) + 'static,
940    ) -> Self {
941        self.interactivity().on_mouse_pressure(listener);
942        self
943    }
944
945    /// Bind the given callback to the mouse pressure event, during the capture phase
946    /// the fluent API equivalent to [`Interactivity::on_mouse_pressure`]
947    ///
948    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
949    fn capture_mouse_pressure(
950        mut self,
951        listener: impl Fn(&MousePressureEvent, &mut Window, &mut App) + 'static,
952    ) -> Self {
953        self.interactivity().capture_mouse_pressure(listener);
954        self
955    }
956
957    /// Bind the given callback to the mouse down event, on any button, during the capture phase,
958    /// when the mouse is outside of the bounds of this element.
959    /// The fluent API equivalent to [`Interactivity::on_mouse_down_out`].
960    ///
961    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
962    fn on_mouse_down_out(
963        mut self,
964        listener: impl Fn(&MouseDownEvent, &mut Window, &mut App) + 'static,
965    ) -> Self {
966        self.interactivity().on_mouse_down_out(listener);
967        self
968    }
969
970    /// Bind the given callback to the mouse down event - for all mouse up events,
971    /// regardless of dispatch phase, mouse button, or whether the mouse is
972    /// inside or outside the bounds of the element.
973    /// The fluent API equivalent to [`Interactivity::on_mouse_up_out`].
974    ///
975    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
976    fn on_mouse_down_all(
977        mut self,
978        listener: impl Fn(&MouseDownEvent, DispatchPhase, &Hitbox, &mut Window, &mut App) + 'static,
979    ) -> Self {
980        self.interactivity().on_mouse_down_all(listener);
981        self
982    }
983
984    /// Bind the given callback to the mouse up event, for the given button, during the capture phase,
985    /// when the mouse is outside of the bounds of this element.
986    /// The fluent API equivalent to [`Interactivity::on_mouse_up_out`].
987    ///
988    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
989    fn on_mouse_up_out(
990        mut self,
991        button: MouseButton,
992        listener: impl Fn(&MouseUpEvent, &mut Window, &mut App) + 'static,
993    ) -> Self {
994        self.interactivity().on_mouse_up_out(button, listener);
995        self
996    }
997
998    /// Bind the given callback to the mouse up event - for all mouse up events,
999    /// regardless of dispatch phase, mouse button, or whether the mouse is
1000    /// inside or outside the bounds of the element.
1001    /// The fluent API equivalent to [`Interactivity::on_mouse_up_out`].
1002    ///
1003    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
1004    fn on_mouse_up_all(
1005        mut self,
1006        listener: impl Fn(&MouseUpEvent, DispatchPhase, &Hitbox, &mut Window, &mut App) + 'static,
1007    ) -> Self {
1008        self.interactivity().on_mouse_up_all(listener);
1009        self
1010    }
1011
1012    /// Bind the given callback to the mouse move event, during the bubble phase.
1013    /// The fluent API equivalent to [`Interactivity::on_mouse_move`].
1014    ///
1015    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
1016    fn on_mouse_move(
1017        mut self,
1018        listener: impl Fn(&MouseMoveEvent, &mut Window, &mut App) + 'static,
1019    ) -> Self {
1020        self.interactivity().on_mouse_move(listener);
1021        self
1022    }
1023
1024    /// Bind the given callback to the mouse exit event, during the bubble phase.
1025    /// The fluent API equivalent to [`Interactivity::on_mouse_exit`].
1026    ///
1027    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
1028    fn on_mouse_exit(
1029        mut self,
1030        listener: impl Fn(&MouseExitEvent, &mut Window, &mut App) + 'static,
1031    ) -> Self {
1032        self.interactivity().on_mouse_exit(listener);
1033        self
1034    }
1035
1036    /// Bind the given callback to the mouse drag event of the given type. Note that this
1037    /// will be called for all move events, inside or outside of this element, as long as the
1038    /// drag was started with this element under the mouse. Useful for implementing draggable
1039    /// UIs that don't conform to a drag and drop style interaction, like resizing.
1040    /// The fluent API equivalent to [`Interactivity::on_drag_move`].
1041    ///
1042    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
1043    fn on_drag_move<T: 'static>(
1044        mut self,
1045        listener: impl Fn(&DragMoveEvent<T>, &mut Window, &mut App) + 'static,
1046    ) -> Self {
1047        self.interactivity().on_drag_move(listener);
1048        self
1049    }
1050
1051    /// Bind the given callback to scroll wheel events during the bubble phase.
1052    /// The fluent API equivalent to [`Interactivity::on_scroll_wheel`].
1053    ///
1054    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
1055    fn on_scroll_wheel(
1056        mut self,
1057        listener: impl Fn(&ScrollWheelEvent, &mut Window, &mut App) + 'static,
1058    ) -> Self {
1059        self.interactivity().on_scroll_wheel(listener);
1060        self
1061    }
1062
1063    /// Bind the given callback to pinch gesture events during the bubble phase.
1064    /// The fluent API equivalent to [`Interactivity::on_pinch`].
1065    ///
1066    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
1067    fn on_pinch(mut self, listener: impl Fn(&PinchEvent, &mut Window, &mut App) + 'static) -> Self {
1068        self.interactivity().on_pinch(listener);
1069        self
1070    }
1071
1072    /// Bind the given callback to pinch gesture events during the capture phase.
1073    /// The fluent API equivalent to [`Interactivity::capture_pinch`].
1074    ///
1075    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
1076    fn capture_pinch(
1077        mut self,
1078        listener: impl Fn(&PinchEvent, &mut Window, &mut App) + 'static,
1079    ) -> Self {
1080        self.interactivity().capture_pinch(listener);
1081        self
1082    }
1083    /// Capture the given action, before normal action dispatch can fire.
1084    /// The fluent API equivalent to [`Interactivity::capture_action`].
1085    ///
1086    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
1087    fn capture_action<A: Action>(
1088        mut self,
1089        listener: impl Fn(&A, &mut Window, &mut App) + 'static,
1090    ) -> Self {
1091        self.interactivity().capture_action(listener);
1092        self
1093    }
1094
1095    /// Bind the given callback to an action dispatch during the bubble phase.
1096    /// The fluent API equivalent to [`Interactivity::on_action`].
1097    ///
1098    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
1099    #[track_caller]
1100    fn on_action<A: Action>(
1101        mut self,
1102        listener: impl Fn(&A, &mut Window, &mut App) + 'static,
1103    ) -> Self {
1104        self.interactivity().on_action(listener);
1105        self
1106    }
1107
1108    /// Bind the given callback to an action dispatch, based on a dynamic action parameter
1109    /// instead of a type parameter. Useful for component libraries that want to expose
1110    /// action bindings to their users.
1111    /// The fluent API equivalent to [`Interactivity::on_boxed_action`].
1112    ///
1113    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
1114    fn on_boxed_action(
1115        mut self,
1116        action: &dyn Action,
1117        listener: impl Fn(&dyn Action, &mut Window, &mut App) + 'static,
1118    ) -> Self {
1119        self.interactivity().on_boxed_action(action, listener);
1120        self
1121    }
1122
1123    /// Bind the given callback to key down events during the bubble phase.
1124    /// The fluent API equivalent to [`Interactivity::on_key_down`].
1125    ///
1126    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
1127    fn on_key_down(
1128        mut self,
1129        listener: impl Fn(&KeyDownEvent, &mut Window, &mut App) + 'static,
1130    ) -> Self {
1131        self.interactivity().on_key_down(listener);
1132        self
1133    }
1134
1135    /// Bind the given callback to key down events during the capture phase.
1136    /// The fluent API equivalent to [`Interactivity::capture_key_down`].
1137    ///
1138    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
1139    fn capture_key_down(
1140        mut self,
1141        listener: impl Fn(&KeyDownEvent, &mut Window, &mut App) + 'static,
1142    ) -> Self {
1143        self.interactivity().capture_key_down(listener);
1144        self
1145    }
1146
1147    /// Bind the given callback to key up events during the bubble phase.
1148    /// The fluent API equivalent to [`Interactivity::on_key_up`].
1149    ///
1150    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
1151    fn on_key_up(
1152        mut self,
1153        listener: impl Fn(&KeyUpEvent, &mut Window, &mut App) + 'static,
1154    ) -> Self {
1155        self.interactivity().on_key_up(listener);
1156        self
1157    }
1158
1159    /// Bind the given callback to key up events during the capture phase.
1160    /// The fluent API equivalent to [`Interactivity::capture_key_up`].
1161    ///
1162    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
1163    fn capture_key_up(
1164        mut self,
1165        listener: impl Fn(&KeyUpEvent, &mut Window, &mut App) + 'static,
1166    ) -> Self {
1167        self.interactivity().capture_key_up(listener);
1168        self
1169    }
1170
1171    /// Bind the given callback to modifiers changing events.
1172    /// The fluent API equivalent to [`Interactivity::on_modifiers_changed`].
1173    ///
1174    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
1175    fn on_modifiers_changed(
1176        mut self,
1177        listener: impl Fn(&ModifiersChangedEvent, &mut Window, &mut App) + 'static,
1178    ) -> Self {
1179        self.interactivity().on_modifiers_changed(listener);
1180        self
1181    }
1182
1183    /// Apply the given style when the given data type is dragged over this element
1184    fn drag_over<S: 'static>(
1185        mut self,
1186        f: impl 'static + Fn(StyleRefinement, &S, &mut Window, &mut App) -> StyleRefinement,
1187    ) -> Self {
1188        self.interactivity().drag_over_styles.push((
1189            TypeId::of::<S>(),
1190            Box::new(move |currently_dragged: &dyn Any, window, cx| {
1191                f(
1192                    StyleRefinement::default(),
1193                    currently_dragged.downcast_ref::<S>().unwrap(),
1194                    window,
1195                    cx,
1196                )
1197            }),
1198        ));
1199        self
1200    }
1201
1202    /// Apply the given style when the given data type is dragged over this element's group
1203    fn group_drag_over<S: 'static>(
1204        mut self,
1205        group_name: impl Into<SharedString>,
1206        f: impl FnOnce(StyleRefinement) -> StyleRefinement,
1207    ) -> Self {
1208        self.interactivity().group_drag_over_styles.push((
1209            TypeId::of::<S>(),
1210            GroupStyle {
1211                group: group_name.into(),
1212                style: Box::new(f(StyleRefinement::default())),
1213            },
1214        ));
1215        self
1216    }
1217
1218    /// Bind the given callback to drop events of the given type, whether or not the drag started on this element.
1219    /// The fluent API equivalent to [`Interactivity::on_drop`].
1220    ///
1221    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
1222    fn on_drop<T: 'static>(
1223        mut self,
1224        listener: impl Fn(&T, &mut Window, &mut App) + 'static,
1225    ) -> Self {
1226        self.interactivity().on_drop(listener);
1227        self
1228    }
1229
1230    /// Use the given predicate to determine whether or not a drop event should be dispatched to this element.
1231    /// The fluent API equivalent to [`Interactivity::can_drop`].
1232    fn can_drop(
1233        mut self,
1234        predicate: impl Fn(&dyn Any, &mut Window, &mut App) -> bool + 'static,
1235    ) -> Self {
1236        self.interactivity().can_drop(predicate);
1237        self
1238    }
1239
1240    /// Block the mouse from all interactions with elements behind this element's hitbox. Typically
1241    /// `block_mouse_except_scroll` should be preferred.
1242    /// The fluent API equivalent to [`Interactivity::occlude_mouse`].
1243    fn occlude(mut self) -> Self {
1244        self.interactivity().occlude_mouse();
1245        self
1246    }
1247
1248    /// Set the bounds of this element as a window control area for the platform window.
1249    /// The fluent API equivalent to [`Interactivity::window_control_area`].
1250    fn window_control_area(mut self, area: WindowControlArea) -> Self {
1251        self.interactivity().window_control_area(area);
1252        self
1253    }
1254
1255    /// Block non-scroll mouse interactions with elements behind this element's hitbox.
1256    /// The fluent API equivalent to [`Interactivity::block_mouse_except_scroll`].
1257    ///
1258    /// See [`Hitbox::is_hovered`] for details.
1259    fn block_mouse_except_scroll(mut self) -> Self {
1260        self.interactivity().block_mouse_except_scroll();
1261        self
1262    }
1263
1264    /// Set the given styles to be applied when this element, specifically, is focused.
1265    /// Requires that the element is focusable. Elements can be made focusable using [`InteractiveElement::track_focus`].
1266    fn focus(mut self, f: impl FnOnce(StyleRefinement) -> StyleRefinement) -> Self
1267    where
1268        Self: Sized,
1269    {
1270        self.interactivity().focus_style = Some(Box::new(f(StyleRefinement::default())));
1271        self
1272    }
1273
1274    /// Set the given styles to be applied when this element is inside another element that is focused.
1275    /// Requires that the element is focusable. Elements can be made focusable using [`InteractiveElement::track_focus`].
1276    fn in_focus(mut self, f: impl FnOnce(StyleRefinement) -> StyleRefinement) -> Self
1277    where
1278        Self: Sized,
1279    {
1280        self.interactivity().in_focus_style = Some(Box::new(f(StyleRefinement::default())));
1281        self
1282    }
1283
1284    /// Set the given styles to be applied when this element is focused via keyboard navigation.
1285    /// This is similar to CSS's `:focus-visible` pseudo-class - it only applies when the element
1286    /// is focused AND the user is navigating via keyboard (not mouse clicks).
1287    /// Requires that the element is focusable. Elements can be made focusable using [`InteractiveElement::track_focus`].
1288    fn focus_visible(mut self, f: impl FnOnce(StyleRefinement) -> StyleRefinement) -> Self
1289    where
1290        Self: Sized,
1291    {
1292        self.interactivity().focus_visible_style = Some(Box::new(f(StyleRefinement::default())));
1293        self
1294    }
1295}
1296
1297/// A trait for elements that want to use the standard GPUI interactivity features
1298/// that require state.
1299pub trait StatefulInteractiveElement: InteractiveElement {
1300    /// Set the accessible role for this element.
1301    ///
1302    /// See the [accessibility guide](crate::_accessibility) for an overview.
1303    fn role(mut self, role: accesskit::Role) -> Self {
1304        debug_assert!(
1305            role != accesskit::Role::GenericContainer,
1306            "GenericContainer is filtered out of the a11y tree and has no effect"
1307        );
1308        self.interactivity().override_role = Some(role);
1309        self
1310    }
1311
1312    /// Set the accessible label for this element.
1313    fn aria_label(mut self, label: impl Into<SharedString>) -> Self {
1314        self.interactivity().aria.label = Some(label.into());
1315        self
1316    }
1317
1318    /// Set the accessible description for this element. Unlike the label (which
1319    /// names the element), the description provides supplementary information
1320    /// that assistive technology announces after the name, role, and value -
1321    /// for example a settings subtitle or a hint.
1322    fn aria_description(mut self, description: impl Into<SharedString>) -> Self {
1323        self.interactivity().aria.description = Some(description.into());
1324        self
1325    }
1326
1327    /// Set the keyboard shortcut(s) that activate this element, announced by
1328    /// assistive technology (maps to AccessKit's `keyboard_shortcut`).
1329    ///
1330    /// Note that this does not create a keymap. It simply instructs assistive
1331    /// technology what the keymap is.
1332    fn aria_keyshortcuts(mut self, keyshortcuts: impl Into<SharedString>) -> Self {
1333        self.interactivity().aria.keyshortcuts = Some(keyshortcuts.into());
1334        self
1335    }
1336
1337    /// Report this element as the focused node in the accessibility tree,
1338    /// overriding the element that holds real keyboard focus — but only while
1339    /// one of its ancestors actually holds focus.
1340    ///
1341    /// This implements the `aria-activedescendant` pattern for composite
1342    /// widgets that keep keyboard focus on a container (e.g. a menu or
1343    /// listbox) while a child is "selected": set this on the selected child so
1344    /// assistive technology announces and highlights it as focused.
1345    ///
1346    /// The element must also have a [`role`][Self::role] (and an id) so it
1347    /// produces an accessibility node. Unlike the web's container-side
1348    /// `aria-activedescendant`, this is set on the descendant; GPUI honors it
1349    /// only when a focused ancestor is present in the tree, so it is safe to
1350    /// set unconditionally on the selected child — if the container isn't
1351    /// focused, the claim is ignored.
1352    fn aria_active_descendant(mut self) -> Self {
1353        self.interactivity().report_active_descendant_focus = true;
1354        self
1355    }
1356
1357    /// Contribute synthetic accessibility nodes — nodes that don't correspond
1358    /// to any element — as children of this element's a11y node. For example,
1359    /// text runs describing an editor's text content.
1360    ///
1361    /// The closure is called after this element is prepainted, and only if it
1362    /// contributed a node to the accessibility tree (i.e. it has an id and a
1363    /// [`role`][StatefulInteractiveElement::role]).
1364    ///
1365    /// See [`Element::a11y_synthetic_children`] for details.
1366    fn a11y_synthetic_children(
1367        mut self,
1368        f: impl FnOnce(&mut crate::A11ySubtreeBuilder) + 'static,
1369    ) -> Self {
1370        self.interactivity().a11y_synthetic_children = Some(Box::new(f));
1371        self
1372    }
1373
1374    /// Set the selected state for this element.
1375    fn aria_selected(mut self, selected: bool) -> Self {
1376        self.interactivity().aria.selected = Some(selected);
1377        self
1378    }
1379
1380    /// Set the expanded state for this element.
1381    fn aria_expanded(mut self, expanded: bool) -> Self {
1382        self.interactivity().aria.expanded = Some(expanded);
1383        self
1384    }
1385
1386    /// Set the toggled state for this element.
1387    fn aria_toggled(mut self, toggled: accesskit::Toggled) -> Self {
1388        self.interactivity().aria.toggled = Some(toggled);
1389        self
1390    }
1391
1392    /// Set the numeric value for this element.
1393    fn aria_numeric_value(mut self, value: f64) -> Self {
1394        self.interactivity().aria.numeric_value = Some(value);
1395        self
1396    }
1397
1398    /// Set the step by which assistive technology should expect the numeric
1399    /// value of this element to change (e.g. when incrementing a spin button).
1400    fn aria_numeric_value_step(mut self, step: f64) -> Self {
1401        self.interactivity().aria.numeric_value_step = Some(step);
1402        self
1403    }
1404
1405    /// Set the string value of this element, e.g. the text content of a simple
1406    /// text input.
1407    fn aria_value(mut self, value: impl Into<SharedString>) -> Self {
1408        self.interactivity().aria.value = Some(value.into());
1409        self
1410    }
1411
1412    /// Set the placeholder text reported to assistive technology for this
1413    /// element, shown when a text input is empty.
1414    fn aria_placeholder(mut self, placeholder: impl Into<SharedString>) -> Self {
1415        self.interactivity().aria.placeholder = Some(placeholder.into());
1416        self
1417    }
1418
1419    /// Set the minimum numeric value for this element.
1420    fn aria_min_numeric_value(mut self, value: f64) -> Self {
1421        self.interactivity().aria.min_numeric_value = Some(value);
1422        self
1423    }
1424
1425    /// Set the maximum numeric value for this element.
1426    fn aria_max_numeric_value(mut self, value: f64) -> Self {
1427        self.interactivity().aria.max_numeric_value = Some(value);
1428        self
1429    }
1430
1431    /// Set the orientation of this element.
1432    fn aria_orientation(mut self, orientation: accesskit::Orientation) -> Self {
1433        self.interactivity().aria.orientation = Some(orientation);
1434        self
1435    }
1436
1437    /// Set the heading level of this element.
1438    fn aria_level(mut self, level: usize) -> Self {
1439        self.interactivity().aria.level = Some(level);
1440        self
1441    }
1442
1443    /// Set the position in set of this element.
1444    fn aria_position_in_set(mut self, position: usize) -> Self {
1445        self.interactivity().aria.position_in_set = Some(position);
1446        self
1447    }
1448
1449    /// Set the size of set for this element.
1450    fn aria_size_of_set(mut self, size: usize) -> Self {
1451        self.interactivity().aria.size_of_set = Some(size);
1452        self
1453    }
1454
1455    /// Set the row index for this element.
1456    fn aria_row_index(mut self, index: usize) -> Self {
1457        self.interactivity().aria.row_index = Some(index);
1458        self
1459    }
1460
1461    /// Set the column index for this element.
1462    fn aria_column_index(mut self, index: usize) -> Self {
1463        self.interactivity().aria.column_index = Some(index);
1464        self
1465    }
1466
1467    /// Set the row count for this element.
1468    fn aria_row_count(mut self, count: usize) -> Self {
1469        self.interactivity().aria.row_count = Some(count);
1470        self
1471    }
1472
1473    /// Set the column count for this element.
1474    fn aria_column_count(mut self, count: usize) -> Self {
1475        self.interactivity().aria.column_count = Some(count);
1476        self
1477    }
1478
1479    /// Register a handler for an accessibility action on this element.
1480    /// The handler is called when a screen reader requests the given action.
1481    ///
1482    /// See the [accessibility guide](crate::_accessibility) for an overview.
1483    fn on_a11y_action(
1484        mut self,
1485        action: accesskit::Action,
1486        listener: impl FnMut(Option<&accesskit::ActionData>, &mut crate::Window, &mut crate::App)
1487        + 'static,
1488    ) -> Self {
1489        self.interactivity()
1490            .a11y_action_listeners
1491            .push((action, Box::new(listener)));
1492        self
1493    }
1494
1495    /// Set this element to focusable.
1496    fn focusable(mut self) -> Self {
1497        self.interactivity().focusable = true;
1498        self
1499    }
1500
1501    /// Set the overflow x and y to scroll.
1502    fn overflow_scroll(mut self) -> Self {
1503        self.interactivity().base_style.overflow.x = Some(Overflow::Scroll);
1504        self.interactivity().base_style.overflow.y = Some(Overflow::Scroll);
1505        self
1506    }
1507
1508    /// Set the overflow x to scroll.
1509    fn overflow_x_scroll(mut self) -> Self {
1510        self.interactivity().base_style.overflow.x = Some(Overflow::Scroll);
1511        self
1512    }
1513
1514    /// Set the overflow y to scroll.
1515    fn overflow_y_scroll(mut self) -> Self {
1516        self.interactivity().base_style.overflow.y = Some(Overflow::Scroll);
1517        self
1518    }
1519
1520    /// Restrict scrolling of this element to the axis of the input gesture.
1521    ///
1522    /// See [`Style::restrict_scroll_to_axis`](crate::Style::restrict_scroll_to_axis) for details.
1523    fn restrict_scroll_to_axis(mut self) -> Self {
1524        self.interactivity().base_style.restrict_scroll_to_axis = Some(true);
1525        self
1526    }
1527
1528    /// Track the scroll state of this element with the given handle.
1529    fn track_scroll(mut self, scroll_handle: &ScrollHandle) -> Self {
1530        self.interactivity().tracked_scroll_handle = Some(scroll_handle.clone());
1531        self
1532    }
1533
1534    /// Track the scroll state of this element with the given handle.
1535    fn anchor_scroll(mut self, scroll_anchor: Option<ScrollAnchor>) -> Self {
1536        self.interactivity().scroll_anchor = scroll_anchor;
1537        self
1538    }
1539
1540    /// Set the given styles to be applied when this element is active.
1541    fn active(mut self, f: impl FnOnce(StyleRefinement) -> StyleRefinement) -> Self
1542    where
1543        Self: Sized,
1544    {
1545        self.interactivity().active_style = Some(Box::new(f(StyleRefinement::default())));
1546        self
1547    }
1548
1549    /// Set the given styles to be applied when this element's group is active.
1550    fn group_active(
1551        mut self,
1552        group_name: impl Into<SharedString>,
1553        f: impl FnOnce(StyleRefinement) -> StyleRefinement,
1554    ) -> Self
1555    where
1556        Self: Sized,
1557    {
1558        self.interactivity().group_active_style = Some(GroupStyle {
1559            group: group_name.into(),
1560            style: Box::new(f(StyleRefinement::default())),
1561        });
1562        self
1563    }
1564
1565    /// Bind the given callback to click events of this element.
1566    /// The fluent API equivalent to [`Interactivity::on_click`].
1567    ///
1568    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
1569    fn on_click(mut self, listener: impl Fn(&ClickEvent, &mut Window, &mut App) + 'static) -> Self
1570    where
1571        Self: Sized,
1572    {
1573        self.interactivity().on_click(listener);
1574        self
1575    }
1576
1577    /// Bind the given callback to non-primary click events of this element.
1578    /// The fluent API equivalent to [`Interactivity::on_aux_click`].
1579    ///
1580    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
1581    fn on_aux_click(
1582        mut self,
1583        listener: impl Fn(&ClickEvent, &mut Window, &mut App) + 'static,
1584    ) -> Self
1585    where
1586        Self: Sized,
1587    {
1588        self.interactivity().on_aux_click(listener);
1589        self
1590    }
1591
1592    /// On drag initiation, this callback will be used to create a new view to render the dragged value for a
1593    /// drag and drop operation. This API should also be used as the equivalent of 'on drag start' with
1594    /// the [`InteractiveElement::on_drag_move`] API.
1595    /// The callback also has access to the offset of triggering click from the origin of parent element.
1596    /// The fluent API equivalent to [`Interactivity::on_drag`].
1597    ///
1598    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
1599    fn on_drag<T, W>(
1600        mut self,
1601        value: T,
1602        constructor: impl Fn(&T, Point<Pixels>, &mut Window, &mut App) -> Entity<W> + 'static,
1603    ) -> Self
1604    where
1605        Self: Sized,
1606        T: 'static,
1607        W: 'static + Render,
1608    {
1609        self.interactivity().on_drag(value, constructor);
1610        self
1611    }
1612
1613    /// Registers a callback resolving a payload to offer the platform if a drag started by this
1614    /// element leaves the window. It is invoked at most once per drag gesture, when the pointer
1615    /// exits the viewport. Must be called after [`Self::on_drag`], with the same dragged value
1616    /// type `T`.
1617    /// The fluent API equivalent to [`Interactivity::external_drag_payload`].
1618    fn external_drag_payload<T>(
1619        mut self,
1620        resolver: impl Fn(&T, &mut Window, &mut App) -> Option<ExternalDragPayload> + 'static,
1621    ) -> Self
1622    where
1623        Self: Sized,
1624        T: 'static,
1625    {
1626        self.interactivity().external_drag_payload(resolver);
1627        self
1628    }
1629
1630    /// Bind the given callback on the hover start and end events of this element. Note that the boolean
1631    /// passed to the callback is true when the hover starts and false when it ends.
1632    /// The fluent API equivalent to [`Interactivity::on_hover`].
1633    ///
1634    /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
1635    fn on_hover(mut self, listener: impl Fn(&bool, &mut Window, &mut App) + 'static) -> Self
1636    where
1637        Self: Sized,
1638    {
1639        self.interactivity().on_hover(listener);
1640        self
1641    }
1642
1643    /// Use the given callback to construct a new tooltip view when the mouse hovers over this element.
1644    /// The fluent API equivalent to [`Interactivity::tooltip`].
1645    fn tooltip(mut self, build_tooltip: impl Fn(&mut Window, &mut App) -> AnyView + 'static) -> Self
1646    where
1647        Self: Sized,
1648    {
1649        self.interactivity().tooltip(build_tooltip);
1650        self
1651    }
1652
1653    /// Use the given callback to construct a new tooltip view when the mouse hovers over this element.
1654    /// The tooltip itself is also hoverable and won't disappear when the user moves the mouse into
1655    /// the tooltip. The fluent API equivalent to [`Interactivity::hoverable_tooltip`].
1656    fn hoverable_tooltip(
1657        mut self,
1658        build_tooltip: impl Fn(&mut Window, &mut App) -> AnyView + 'static,
1659    ) -> Self
1660    where
1661        Self: Sized,
1662    {
1663        self.interactivity().hoverable_tooltip(build_tooltip);
1664        self
1665    }
1666
1667    /// Set the delay before this element's tooltip is shown.
1668    /// The fluent API equivalent to [`Interactivity::tooltip_show_delay`].
1669    fn tooltip_show_delay(mut self, delay: Duration) -> Self
1670    where
1671        Self: Sized,
1672    {
1673        self.interactivity().tooltip_show_delay(delay);
1674        self
1675    }
1676}
1677
1678pub(crate) type MouseDownListener =
1679    Box<dyn Fn(&MouseDownEvent, DispatchPhase, &Hitbox, &mut Window, &mut App) + 'static>;
1680pub(crate) type MouseUpListener =
1681    Box<dyn Fn(&MouseUpEvent, DispatchPhase, &Hitbox, &mut Window, &mut App) + 'static>;
1682pub(crate) type MousePressureListener =
1683    Box<dyn Fn(&MousePressureEvent, DispatchPhase, &Hitbox, &mut Window, &mut App) + 'static>;
1684pub(crate) type MouseMoveListener =
1685    Box<dyn Fn(&MouseMoveEvent, DispatchPhase, &Hitbox, &mut Window, &mut App) + 'static>;
1686pub(crate) type MouseExitListener =
1687    Box<dyn Fn(&MouseExitEvent, DispatchPhase, &Hitbox, &mut Window, &mut App) + 'static>;
1688
1689pub(crate) type ScrollWheelListener =
1690    Box<dyn Fn(&ScrollWheelEvent, DispatchPhase, &Hitbox, &mut Window, &mut App) + 'static>;
1691
1692pub(crate) type PinchListener =
1693    Box<dyn Fn(&PinchEvent, DispatchPhase, &Hitbox, &mut Window, &mut App) + 'static>;
1694
1695pub(crate) type ClickListener = Rc<dyn Fn(&ClickEvent, &mut Window, &mut App) + 'static>;
1696
1697pub(crate) struct DragListener {
1698    value: Arc<dyn Any>,
1699    render: Box<dyn Fn(&dyn Any, Point<Pixels>, &mut Window, &mut App) -> AnyView + 'static>,
1700    external_payload: Option<ExternalDragPayloadResolver>,
1701}
1702
1703type ExternalDragPayloadResolver =
1704    Box<dyn Fn(&dyn Any, &mut Window, &mut App) -> Option<ExternalDragPayload> + 'static>;
1705
1706type DropListener = Box<dyn Fn(&dyn Any, &mut Window, &mut App) + 'static>;
1707
1708type CanDropPredicate = Box<dyn Fn(&dyn Any, &mut Window, &mut App) -> bool + 'static>;
1709
1710pub(crate) struct TooltipBuilder {
1711    build: Rc<dyn Fn(&mut Window, &mut App) -> AnyView + 'static>,
1712    hoverable: bool,
1713}
1714
1715pub(crate) type KeyDownListener =
1716    Box<dyn Fn(&KeyDownEvent, DispatchPhase, &mut Window, &mut App) + 'static>;
1717
1718pub(crate) type KeyUpListener =
1719    Box<dyn Fn(&KeyUpEvent, DispatchPhase, &mut Window, &mut App) + 'static>;
1720
1721pub(crate) type ModifiersChangedListener =
1722    Box<dyn Fn(&ModifiersChangedEvent, &mut Window, &mut App) + 'static>;
1723
1724pub(crate) type ActionListener =
1725    Box<dyn Fn(&dyn Any, DispatchPhase, &mut Window, &mut App) + 'static>;
1726
1727/// Construct a new [`Div`] element
1728#[track_caller]
1729pub fn div() -> Div {
1730    Div {
1731        interactivity: Interactivity::new(),
1732        children: SmallVec::default(),
1733        prepaint_listener: None,
1734        image_cache: None,
1735        prepaint_order_fn: None,
1736    }
1737}
1738
1739/// A [`Div`] element, the all-in-one element for building complex UIs in GPUI
1740pub struct Div {
1741    interactivity: Interactivity,
1742    children: SmallVec<[StackSafe<AnyElement>; 2]>,
1743    prepaint_listener: Option<Box<dyn Fn(Vec<Bounds<Pixels>>, &mut Window, &mut App) + 'static>>,
1744    image_cache: Option<Box<dyn ImageCacheProvider>>,
1745    prepaint_order_fn: Option<Box<dyn Fn(&mut Window, &mut App) -> SmallVec<[usize; 8]>>>,
1746}
1747
1748impl Div {
1749    /// Add a listener to be called when the children of this `Div` are prepainted.
1750    /// This allows you to store the [`Bounds`] of the children for later use.
1751    pub fn on_children_prepainted(
1752        mut self,
1753        listener: impl Fn(Vec<Bounds<Pixels>>, &mut Window, &mut App) + 'static,
1754    ) -> Self {
1755        self.prepaint_listener = Some(Box::new(listener));
1756        self
1757    }
1758
1759    /// Add an image cache at the location of this div in the element tree.
1760    pub fn image_cache(mut self, cache: impl ImageCacheProvider) -> Self {
1761        self.image_cache = Some(Box::new(cache));
1762        self
1763    }
1764
1765    /// Specify a function that determines the order in which children are prepainted.
1766    ///
1767    /// The function is called at prepaint time and should return a vector of child indices
1768    /// in the desired prepaint order. Each index should appear exactly once.
1769    ///
1770    /// This is useful when the prepaint of one child affects state that another child reads.
1771    /// For example, in split editor views, the editor with an autoscroll request should
1772    /// be prepainted first so its scroll position update is visible to the other editor.
1773    pub fn with_dynamic_prepaint_order(
1774        mut self,
1775        order_fn: impl Fn(&mut Window, &mut App) -> SmallVec<[usize; 8]> + 'static,
1776    ) -> Self {
1777        self.prepaint_order_fn = Some(Box::new(order_fn));
1778        self
1779    }
1780}
1781
1782/// A frame state for a `Div` element, which contains layout IDs for its children.
1783///
1784/// This struct is used internally by the `Div` element to manage the layout state of its children
1785/// during the UI update cycle. It holds a small vector of `LayoutId` values, each corresponding to
1786/// a child element of the `Div`. These IDs are used to query the layout engine for the computed
1787/// bounds of the children after the layout phase is complete.
1788pub struct DivFrameState {
1789    child_layout_ids: SmallVec<[LayoutId; 2]>,
1790}
1791
1792/// Interactivity state displayed an manipulated in the inspector.
1793#[derive(Clone)]
1794pub struct DivInspectorState {
1795    /// The inspected element's base style. This is used for both inspecting and modifying the
1796    /// state. In the future it will make sense to separate the read and write, possibly tracking
1797    /// the modifications.
1798    #[cfg(any(feature = "inspector", debug_assertions))]
1799    pub base_style: Box<StyleRefinement>,
1800    /// Inspects the bounds of the element.
1801    pub bounds: Bounds<Pixels>,
1802    /// Size of the children of the element, or `bounds.size` if it has no children.
1803    pub content_size: Size<Pixels>,
1804}
1805
1806impl Styled for Div {
1807    fn style(&mut self) -> &mut StyleRefinement {
1808        &mut self.interactivity.base_style
1809    }
1810}
1811
1812impl InteractiveElement for Div {
1813    fn interactivity(&mut self) -> &mut Interactivity {
1814        &mut self.interactivity
1815    }
1816}
1817
1818impl ParentElement for Div {
1819    fn extend(&mut self, elements: impl IntoIterator<Item = AnyElement>) {
1820        self.children
1821            .extend(elements.into_iter().map(StackSafe::new))
1822    }
1823}
1824
1825impl Element for Div {
1826    type RequestLayoutState = DivFrameState;
1827    type PrepaintState = Option<Hitbox>;
1828
1829    fn id(&self) -> Option<ElementId> {
1830        self.interactivity.element_id.clone()
1831    }
1832
1833    fn source_location(&self) -> Option<&'static std::panic::Location<'static>> {
1834        self.interactivity.source_location()
1835    }
1836
1837    fn a11y_role(&self) -> Option<accesskit::Role> {
1838        // Nodes with `GenericContainer` should never be reported to accesskit.
1839        // Equivalent to an HTML div with no role.
1840        self.interactivity
1841            .override_role
1842            .filter(|role| *role != accesskit::Role::GenericContainer)
1843    }
1844
1845    fn write_a11y_info(&self, node: &mut accesskit::Node) {
1846        self.interactivity.write_a11y_info(node);
1847    }
1848
1849    fn a11y_synthetic_children(
1850        &mut self,
1851        _prepaint: &mut Self::PrepaintState,
1852        builder: &mut crate::A11ySubtreeBuilder,
1853    ) {
1854        if let Some(f) = self.interactivity.a11y_synthetic_children.take() {
1855            f(builder);
1856        }
1857    }
1858
1859    #[stacksafe]
1860    fn request_layout(
1861        &mut self,
1862        global_id: Option<&GlobalElementId>,
1863        inspector_id: Option<&InspectorElementId>,
1864        window: &mut Window,
1865        cx: &mut App,
1866    ) -> (LayoutId, Self::RequestLayoutState) {
1867        let mut child_layout_ids = SmallVec::new();
1868        let image_cache = self
1869            .image_cache
1870            .as_mut()
1871            .map(|provider| provider.provide(window, cx));
1872
1873        let layout_id = window.with_image_cache(image_cache, |window| {
1874            self.interactivity.request_layout(
1875                global_id,
1876                inspector_id,
1877                window,
1878                cx,
1879                |style, window, cx| {
1880                    window.with_text_style(style.text_style().cloned(), |window| {
1881                        child_layout_ids = self
1882                            .children
1883                            .iter_mut()
1884                            .map(|child| child.request_layout(window, cx))
1885                            .collect::<SmallVec<_>>();
1886                        window.request_layout(style, child_layout_ids.iter().copied(), cx)
1887                    })
1888                },
1889            )
1890        });
1891
1892        (layout_id, DivFrameState { child_layout_ids })
1893    }
1894
1895    #[stacksafe]
1896    fn prepaint(
1897        &mut self,
1898        global_id: Option<&GlobalElementId>,
1899        inspector_id: Option<&InspectorElementId>,
1900        bounds: Bounds<Pixels>,
1901        request_layout: &mut Self::RequestLayoutState,
1902        window: &mut Window,
1903        cx: &mut App,
1904    ) -> Option<Hitbox> {
1905        let image_cache = self
1906            .image_cache
1907            .as_mut()
1908            .map(|provider| provider.provide(window, cx));
1909
1910        let has_prepaint_listener = self.prepaint_listener.is_some();
1911        let mut children_bounds = Vec::with_capacity(if has_prepaint_listener {
1912            request_layout.child_layout_ids.len()
1913        } else {
1914            0
1915        });
1916
1917        let mut child_min = point(Pixels::MAX, Pixels::MAX);
1918        let mut child_max = Point::default();
1919        if let Some(handle) = self.interactivity.scroll_anchor.as_ref() {
1920            *handle.last_origin.borrow_mut() = bounds.origin - window.element_offset();
1921        }
1922        let content_size = if request_layout.child_layout_ids.is_empty() {
1923            bounds.size
1924        } else if let Some(scroll_handle) = self.interactivity.tracked_scroll_handle.as_ref() {
1925            let mut state = scroll_handle.0.borrow_mut();
1926            state.child_bounds = Vec::with_capacity(request_layout.child_layout_ids.len());
1927            for child_layout_id in &request_layout.child_layout_ids {
1928                let child_bounds = window.layout_bounds(*child_layout_id);
1929                child_min = child_min.min(&child_bounds.origin);
1930                child_max = child_max.max(&child_bounds.bottom_right());
1931                state.child_bounds.push(child_bounds);
1932            }
1933            (child_max - child_min).into()
1934        } else {
1935            for child_layout_id in &request_layout.child_layout_ids {
1936                let child_bounds = window.layout_bounds(*child_layout_id);
1937                child_min = child_min.min(&child_bounds.origin);
1938                child_max = child_max.max(&child_bounds.bottom_right());
1939
1940                if has_prepaint_listener {
1941                    children_bounds.push(child_bounds);
1942                }
1943            }
1944            (child_max - child_min).into()
1945        };
1946
1947        if let Some(scroll_handle) = self.interactivity.tracked_scroll_handle.as_ref() {
1948            scroll_handle.scroll_to_active_item();
1949        }
1950
1951        self.interactivity.prepaint(
1952            global_id,
1953            inspector_id,
1954            bounds,
1955            content_size,
1956            window,
1957            cx,
1958            |style, scroll_offset, hitbox, window, cx| {
1959                // skip children
1960                if style.display == Display::None {
1961                    return hitbox;
1962                }
1963
1964                window.with_image_cache(image_cache, |window| {
1965                    window.with_element_offset(scroll_offset, |window| {
1966                        if let Some(order_fn) = &self.prepaint_order_fn {
1967                            let order = order_fn(window, cx);
1968                            for idx in order {
1969                                if let Some(child) = self.children.get_mut(idx) {
1970                                    child.prepaint(window, cx);
1971                                }
1972                            }
1973                        } else {
1974                            for child in &mut self.children {
1975                                child.prepaint(window, cx);
1976                            }
1977                        }
1978                    });
1979
1980                    if let Some(listener) = self.prepaint_listener.as_ref() {
1981                        listener(children_bounds, window, cx);
1982                    }
1983                });
1984
1985                hitbox
1986            },
1987        )
1988    }
1989
1990    #[stacksafe]
1991    fn paint(
1992        &mut self,
1993        global_id: Option<&GlobalElementId>,
1994        inspector_id: Option<&InspectorElementId>,
1995        bounds: Bounds<Pixels>,
1996        _request_layout: &mut Self::RequestLayoutState,
1997        hitbox: &mut Option<Hitbox>,
1998        window: &mut Window,
1999        cx: &mut App,
2000    ) {
2001        let image_cache = self
2002            .image_cache
2003            .as_mut()
2004            .map(|provider| provider.provide(window, cx));
2005
2006        window.with_image_cache(image_cache, |window| {
2007            self.interactivity.paint(
2008                global_id,
2009                inspector_id,
2010                bounds,
2011                hitbox.as_ref(),
2012                window,
2013                cx,
2014                |style, window, cx| {
2015                    // skip children
2016                    if style.display == Display::None {
2017                        return;
2018                    }
2019
2020                    for child in &mut self.children {
2021                        child.paint(window, cx);
2022                    }
2023                },
2024            )
2025        });
2026    }
2027}
2028
2029impl IntoElement for Div {
2030    type Element = Self;
2031
2032    fn into_element(self) -> Self::Element {
2033        self
2034    }
2035}
2036
2037#[derive(Default)]
2038pub(crate) struct AriaProperties {
2039    pub(crate) label: Option<SharedString>,
2040    pub(crate) description: Option<SharedString>,
2041    pub(crate) keyshortcuts: Option<SharedString>,
2042    pub(crate) selected: Option<bool>,
2043    pub(crate) expanded: Option<bool>,
2044    pub(crate) toggled: Option<accesskit::Toggled>,
2045    pub(crate) numeric_value: Option<f64>,
2046    pub(crate) min_numeric_value: Option<f64>,
2047    pub(crate) max_numeric_value: Option<f64>,
2048    pub(crate) numeric_value_step: Option<f64>,
2049    pub(crate) value: Option<SharedString>,
2050    pub(crate) placeholder: Option<SharedString>,
2051    pub(crate) orientation: Option<accesskit::Orientation>,
2052    pub(crate) level: Option<usize>,
2053    pub(crate) position_in_set: Option<usize>,
2054    pub(crate) size_of_set: Option<usize>,
2055    pub(crate) row_index: Option<usize>,
2056    pub(crate) column_index: Option<usize>,
2057    pub(crate) row_count: Option<usize>,
2058    pub(crate) column_count: Option<usize>,
2059}
2060
2061/// The interactivity struct. Powers all of the general-purpose
2062/// interactivity in the `Div` element.
2063#[derive(Default)]
2064pub struct Interactivity {
2065    /// The element ID of the element. In id is required to support a stateful subset of the interactivity such as on_click.
2066    pub element_id: Option<ElementId>,
2067    /// Whether the element was clicked. This will only be present after layout.
2068    pub active: Option<bool>,
2069    /// Whether the element was hovered. This will only be present after paint if an hitbox
2070    /// was created for the interactive element.
2071    pub hovered: Option<bool>,
2072    pub(crate) tooltip_id: Option<TooltipId>,
2073    pub(crate) content_size: Size<Pixels>,
2074    pub(crate) key_context: Option<KeyContext>,
2075    pub(crate) focusable: bool,
2076    pub(crate) tracked_focus_handle: Option<FocusHandle>,
2077    pub(crate) tracked_scroll_handle: Option<ScrollHandle>,
2078    pub(crate) scroll_anchor: Option<ScrollAnchor>,
2079    pub(crate) scroll_offset: Option<Rc<RefCell<Point<Pixels>>>>,
2080    pub(crate) ongoing_scroll: Option<Rc<RefCell<OngoingScroll>>>,
2081    pub(crate) group: Option<SharedString>,
2082    /// The base style of the element, before any modifications are applied
2083    /// by focus, active, etc.
2084    pub base_style: Box<StyleRefinement>,
2085    pub(crate) focus_style: Option<Box<StyleRefinement>>,
2086    pub(crate) in_focus_style: Option<Box<StyleRefinement>>,
2087    pub(crate) focus_visible_style: Option<Box<StyleRefinement>>,
2088    pub(crate) hover_style: Option<Box<StyleRefinement>>,
2089    pub(crate) group_hover_style: Option<GroupStyle>,
2090    pub(crate) active_style: Option<Box<StyleRefinement>>,
2091    pub(crate) group_active_style: Option<GroupStyle>,
2092    pub(crate) drag_over_styles: Vec<(
2093        TypeId,
2094        Box<dyn Fn(&dyn Any, &mut Window, &mut App) -> StyleRefinement>,
2095    )>,
2096    pub(crate) group_drag_over_styles: Vec<(TypeId, GroupStyle)>,
2097    pub(crate) mouse_down_listeners: Vec<MouseDownListener>,
2098    pub(crate) mouse_up_listeners: Vec<MouseUpListener>,
2099    pub(crate) mouse_pressure_listeners: Vec<MousePressureListener>,
2100    pub(crate) mouse_move_listeners: Vec<MouseMoveListener>,
2101    pub(crate) mouse_exit_listeners: Vec<MouseExitListener>,
2102    pub(crate) scroll_wheel_listeners: Vec<ScrollWheelListener>,
2103    pub(crate) pinch_listeners: Vec<PinchListener>,
2104    pub(crate) key_down_listeners: Vec<KeyDownListener>,
2105    pub(crate) key_up_listeners: Vec<KeyUpListener>,
2106    pub(crate) modifiers_changed_listeners: Vec<ModifiersChangedListener>,
2107    pub(crate) action_listeners: Vec<(TypeId, ActionListener)>,
2108    pub(crate) drop_listeners: Vec<(TypeId, DropListener)>,
2109    pub(crate) can_drop_predicate: Option<CanDropPredicate>,
2110    pub(crate) click_listeners: Vec<ClickListener>,
2111    pub(crate) aux_click_listeners: Vec<ClickListener>,
2112    pub(crate) drag_listener: Option<DragListener>,
2113    pub(crate) hover_listener: Option<Box<dyn Fn(&bool, &mut Window, &mut App)>>,
2114    pub(crate) tooltip_builder: Option<TooltipBuilder>,
2115    pub(crate) tooltip_show_delay: Option<Duration>,
2116    pub(crate) window_control: Option<WindowControlArea>,
2117    pub(crate) hitbox_behavior: HitboxBehavior,
2118    pub(crate) tab_index: Option<isize>,
2119    pub(crate) tab_group: bool,
2120    pub(crate) tab_stop: bool,
2121
2122    pub(crate) a11y_action_listeners:
2123        Vec<(accesskit::Action, crate::window::a11y::A11yActionListener)>,
2124    pub(crate) a11y_synthetic_children: Option<Box<dyn FnOnce(&mut crate::A11ySubtreeBuilder)>>,
2125    pub(crate) report_active_descendant_focus: bool,
2126    pub(crate) override_role: Option<accesskit::Role>,
2127    pub(crate) aria: AriaProperties,
2128
2129    #[cfg(any(feature = "inspector", debug_assertions))]
2130    pub(crate) source_location: Option<&'static core::panic::Location<'static>>,
2131
2132    #[cfg(any(test, feature = "test-support"))]
2133    pub(crate) debug_selector: Option<String>,
2134}
2135
2136impl Interactivity {
2137    /// Assigns the current scroll offset of an element. No-op if the element's
2138    /// style does not have overflow enabled.
2139    ///
2140    /// Should only be called during the `request_layout` phase.
2141    pub fn set_scroll_offset(
2142        &self,
2143        global_id: Option<&GlobalElementId>,
2144        window: &mut Window,
2145        point: Point<Pixels>,
2146    ) {
2147        window.with_optional_element_state::<gpui::InteractiveElementState, _>(
2148            global_id,
2149            |element_state, _window| {
2150                let mut element_state =
2151                    element_state.map(|element_state| element_state.unwrap_or_default());
2152                let overflow = &self.base_style.overflow;
2153                if (overflow.x == Some(Overflow::Scroll) || overflow.y == Some(Overflow::Scroll))
2154                    && let Some(element_state) = element_state.as_mut()
2155                {
2156                    let scroll_offset = element_state.scroll_offset.get_or_insert_with(Rc::default);
2157                    *scroll_offset.borrow_mut() = point;
2158                }
2159                ((), element_state)
2160            },
2161        );
2162    }
2163}
2164
2165impl Interactivity {
2166    /// Layout this element according to this interactivity state's configured styles
2167    pub fn request_layout(
2168        &mut self,
2169        global_id: Option<&GlobalElementId>,
2170        _inspector_id: Option<&InspectorElementId>,
2171        window: &mut Window,
2172        cx: &mut App,
2173        f: impl FnOnce(Style, &mut Window, &mut App) -> LayoutId,
2174    ) -> LayoutId {
2175        #[cfg(any(feature = "inspector", debug_assertions))]
2176        window.with_inspector_state(
2177            _inspector_id,
2178            cx,
2179            |inspector_state: &mut Option<DivInspectorState>, _window| {
2180                if let Some(inspector_state) = inspector_state {
2181                    self.base_style = inspector_state.base_style.clone();
2182                } else {
2183                    *inspector_state = Some(DivInspectorState {
2184                        base_style: self.base_style.clone(),
2185                        bounds: Default::default(),
2186                        content_size: Default::default(),
2187                    })
2188                }
2189            },
2190        );
2191
2192        window.with_optional_element_state::<InteractiveElementState, _>(
2193            global_id,
2194            |element_state, window| {
2195                let mut element_state =
2196                    element_state.map(|element_state| element_state.unwrap_or_default());
2197
2198                if let Some(element_state) = element_state.as_ref()
2199                    && cx.has_active_drag()
2200                {
2201                    if let Some(pending_mouse_down) = element_state.pending_mouse_down.as_ref() {
2202                        *pending_mouse_down.borrow_mut() = None;
2203                    }
2204                    if let Some(clicked_state) = element_state.clicked_state.as_ref() {
2205                        *clicked_state.borrow_mut() = ElementClickedState::default();
2206                    }
2207                }
2208
2209                // Ensure we store a focus handle in our element state if we're focusable.
2210                // If there's an explicit focus handle we're tracking, use that. Otherwise
2211                // create a new handle and store it in the element state, which lives for as
2212                // as frames contain an element with this id.
2213                if self.focusable
2214                    && self.tracked_focus_handle.is_none()
2215                    && let Some(element_state) = element_state.as_mut()
2216                {
2217                    let mut handle = element_state
2218                        .focus_handle
2219                        .get_or_insert_with(|| cx.focus_handle())
2220                        .clone()
2221                        .tab_stop(self.tab_stop);
2222
2223                    if let Some(index) = self.tab_index {
2224                        handle = handle.tab_index(index);
2225                    }
2226
2227                    self.tracked_focus_handle = Some(handle);
2228                }
2229
2230                if let Some(scroll_handle) = self.tracked_scroll_handle.as_ref() {
2231                    let scroll_handle_state = scroll_handle.0.borrow();
2232                    self.scroll_offset = Some(scroll_handle_state.offset.clone());
2233                    self.ongoing_scroll = Some(scroll_handle_state.ongoing_scroll.clone());
2234                } else if (self.base_style.overflow.x == Some(Overflow::Scroll)
2235                    || self.base_style.overflow.y == Some(Overflow::Scroll))
2236                    && let Some(element_state) = element_state.as_mut()
2237                {
2238                    self.scroll_offset = Some(
2239                        element_state
2240                            .scroll_offset
2241                            .get_or_insert_with(Rc::default)
2242                            .clone(),
2243                    );
2244                    self.ongoing_scroll = Some(
2245                        element_state
2246                            .ongoing_scroll
2247                            .get_or_insert_with(|| Rc::new(RefCell::new(OngoingScroll::default())))
2248                            .clone(),
2249                    );
2250                }
2251
2252                let style = self.compute_style_internal(None, element_state.as_mut(), window, cx);
2253                let layout_id = f(style, window, cx);
2254                (layout_id, element_state)
2255            },
2256        )
2257    }
2258
2259    /// Commit the bounds of this element according to this interactivity state's configured styles.
2260    pub fn prepaint<R>(
2261        &mut self,
2262        global_id: Option<&GlobalElementId>,
2263        _inspector_id: Option<&InspectorElementId>,
2264        bounds: Bounds<Pixels>,
2265        content_size: Size<Pixels>,
2266        window: &mut Window,
2267        cx: &mut App,
2268        f: impl FnOnce(&Style, Point<Pixels>, Option<Hitbox>, &mut Window, &mut App) -> R,
2269    ) -> R {
2270        self.content_size = content_size;
2271
2272        #[cfg(any(feature = "inspector", debug_assertions))]
2273        window.with_inspector_state(
2274            _inspector_id,
2275            cx,
2276            |inspector_state: &mut Option<DivInspectorState>, _window| {
2277                if let Some(inspector_state) = inspector_state {
2278                    inspector_state.bounds = bounds;
2279                    inspector_state.content_size = content_size;
2280                }
2281            },
2282        );
2283
2284        if let Some(focus_handle) = self.tracked_focus_handle.as_ref() {
2285            window.set_focus_handle(focus_handle, cx);
2286
2287            if window.a11y.is_active() {
2288                if let Some(global_id) = global_id {
2289                    let node_id = global_id.accesskit_node_id();
2290                    window.a11y.set_focusable(node_id, focus_handle.id);
2291                    if focus_handle.is_focused(window) {
2292                        window.a11y.set_focus(node_id);
2293                    }
2294                } else if focus_handle.is_focused(window) {
2295                    // Focusable, but with no element id it can't have an
2296                    // accessibility node, so screen readers fall back to the
2297                    // whole window.
2298                    window
2299                        .a11y
2300                        .note_focus_without_node(focus_handle.id, "it has no element id");
2301                }
2302            }
2303        }
2304
2305        if self.report_active_descendant_focus && window.a11y.is_active() {
2306            if let Some(global_id) = global_id {
2307                window
2308                    .a11y
2309                    .set_active_descendant(global_id.accesskit_node_id());
2310            }
2311        }
2312        window.with_optional_element_state::<InteractiveElementState, _>(
2313            global_id,
2314            |element_state, window| {
2315                let mut element_state =
2316                    element_state.map(|element_state| element_state.unwrap_or_default());
2317                let style = self.compute_style_internal(None, element_state.as_mut(), window, cx);
2318
2319                if let Some(element_state) = element_state.as_mut() {
2320                    if let Some(clicked_state) = element_state.clicked_state.as_ref() {
2321                        let clicked_state = clicked_state.borrow();
2322                        self.active = Some(clicked_state.element);
2323                    }
2324                    if self.hover_style.is_some() || self.group_hover_style.is_some() {
2325                        element_state
2326                            .hover_state
2327                            .get_or_insert_with(Default::default);
2328                    }
2329                    if let Some(active_tooltip) = element_state.active_tooltip.as_ref() {
2330                        if self.tooltip_builder.is_some() {
2331                            self.tooltip_id = set_tooltip_on_window(active_tooltip, window);
2332                        } else {
2333                            // If there is no longer a tooltip builder, remove the active tooltip.
2334                            element_state.active_tooltip.take();
2335                        }
2336                    }
2337                }
2338
2339                window.with_text_style(style.text_style().cloned(), |window| {
2340                    window.with_content_mask(
2341                        style.overflow_mask(bounds, window.rem_size()),
2342                        |window| {
2343                            let hitbox = if self.should_insert_hitbox(&style, window, cx) {
2344                                Some(window.insert_hitbox(bounds, self.hitbox_behavior))
2345                            } else {
2346                                None
2347                            };
2348
2349                            let scroll_offset =
2350                                self.clamp_scroll_position(bounds, &style, window, cx);
2351                            let result = f(&style, scroll_offset, hitbox, window, cx);
2352                            (result, element_state)
2353                        },
2354                    )
2355                })
2356            },
2357        )
2358    }
2359
2360    fn should_insert_hitbox(&self, style: &Style, window: &Window, cx: &App) -> bool {
2361        self.hitbox_behavior != HitboxBehavior::Normal
2362            || self.window_control.is_some()
2363            || style.mouse_cursor.is_some()
2364            || self.group.is_some()
2365            || self.scroll_offset.is_some()
2366            || self.tracked_focus_handle.is_some()
2367            || self.hover_style.is_some()
2368            || self.group_hover_style.is_some()
2369            || self.hover_listener.is_some()
2370            || !self.mouse_up_listeners.is_empty()
2371            || !self.mouse_pressure_listeners.is_empty()
2372            || !self.mouse_down_listeners.is_empty()
2373            || !self.mouse_move_listeners.is_empty()
2374            || !self.mouse_exit_listeners.is_empty()
2375            || !self.click_listeners.is_empty()
2376            || !self.aux_click_listeners.is_empty()
2377            || !self.scroll_wheel_listeners.is_empty()
2378            || self.has_pinch_listeners()
2379            || self.drag_listener.is_some()
2380            || !self.drop_listeners.is_empty()
2381            || !self.drag_over_styles.is_empty()
2382            || self.tooltip_builder.is_some()
2383            || window.is_inspector_picking(cx)
2384    }
2385
2386    fn clamp_scroll_position(
2387        &self,
2388        bounds: Bounds<Pixels>,
2389        style: &Style,
2390        window: &mut Window,
2391        _cx: &mut App,
2392    ) -> Point<Pixels> {
2393        fn round_to_two_decimals(pixels: Pixels) -> Pixels {
2394            const ROUNDING_FACTOR: f32 = 100.0;
2395            (pixels * ROUNDING_FACTOR).round() / ROUNDING_FACTOR
2396        }
2397
2398        if let Some(scroll_offset) = self.scroll_offset.as_ref() {
2399            let mut scroll_to_bottom = false;
2400            let mut tracked_scroll_handle = self
2401                .tracked_scroll_handle
2402                .as_ref()
2403                .map(|handle| handle.0.borrow_mut());
2404            if let Some(mut scroll_handle_state) = tracked_scroll_handle.as_deref_mut() {
2405                scroll_handle_state.overflow = style.overflow;
2406                scroll_to_bottom = mem::take(&mut scroll_handle_state.scroll_to_bottom);
2407            }
2408
2409            let rem_size = window.rem_size();
2410            let padding = style.padding.to_pixels(bounds.size.into(), rem_size);
2411            let padding_size = size(padding.left + padding.right, padding.top + padding.bottom);
2412            // The floating point values produced by Taffy and ours often vary
2413            // slightly after ~5 decimal places. This can lead to cases where after
2414            // subtracting these, the container becomes scrollable for less than
2415            // 0.00000x pixels. As we generally don't benefit from a precision that
2416            // high for the maximum scroll, we round the scroll max to 2 decimal
2417            // places here.
2418            let padded_content_size = self.content_size + padding_size;
2419            let scroll_max = Point::from(padded_content_size - bounds.size)
2420                .map(round_to_two_decimals)
2421                .max(&Default::default());
2422            // Clamp scroll offset in case scroll max is smaller now (e.g., if children
2423            // were removed or the bounds became larger).
2424            let mut scroll_offset = scroll_offset.borrow_mut();
2425
2426            scroll_offset.x = scroll_offset.x.clamp(-scroll_max.x, px(0.));
2427            if scroll_to_bottom {
2428                scroll_offset.y = -scroll_max.y;
2429            } else {
2430                scroll_offset.y = scroll_offset.y.clamp(-scroll_max.y, px(0.));
2431            }
2432
2433            if let Some(mut scroll_handle_state) = tracked_scroll_handle {
2434                scroll_handle_state.max_offset = scroll_max;
2435                scroll_handle_state.bounds = bounds;
2436            }
2437
2438            *scroll_offset
2439        } else {
2440            Point::default()
2441        }
2442    }
2443
2444    /// Paint this element according to this interactivity state's configured styles
2445    /// and bind the element's mouse and keyboard events.
2446    ///
2447    /// content_size is the size of the content of the element, which may be larger than the
2448    /// element's bounds if the element is scrollable.
2449    ///
2450    /// the final computed style will be passed to the provided function, along
2451    /// with the current scroll offset
2452    pub fn paint(
2453        &mut self,
2454        global_id: Option<&GlobalElementId>,
2455        _inspector_id: Option<&InspectorElementId>,
2456        bounds: Bounds<Pixels>,
2457        hitbox: Option<&Hitbox>,
2458        window: &mut Window,
2459        cx: &mut App,
2460        f: impl FnOnce(&Style, &mut Window, &mut App),
2461    ) {
2462        self.hovered = hitbox.map(|hitbox| hitbox.is_hovered(window));
2463        window.with_optional_element_state::<InteractiveElementState, _>(
2464            global_id,
2465            |element_state, window| {
2466                let mut element_state =
2467                    element_state.map(|element_state| element_state.unwrap_or_default());
2468
2469                let style = self.compute_style_internal(hitbox, element_state.as_mut(), window, cx);
2470
2471                #[cfg(any(feature = "test-support", test))]
2472                if let Some(debug_selector) = &self.debug_selector {
2473                    window
2474                        .next_frame
2475                        .debug_bounds
2476                        .insert(debug_selector.clone(), bounds);
2477                }
2478
2479                self.paint_hover_group_handler(window, cx);
2480
2481                if style.visibility == Visibility::Hidden {
2482                    return ((), element_state);
2483                }
2484
2485                let mut tab_group = None;
2486                if self.tab_group {
2487                    tab_group = self.tab_index;
2488                }
2489
2490                window.with_element_opacity(style.opacity, |window| {
2491                    style.paint(bounds, window, cx, |window: &mut Window, cx: &mut App| {
2492                        window.with_text_style(style.text_style().cloned(), |window| {
2493                            window.with_content_mask(
2494                                style.overflow_mask(bounds, window.rem_size()),
2495                                |window| {
2496                                    window.with_tab_group(tab_group, |window| {
2497                                        // Register the container's own focus handle *inside* its
2498                                        // tab group, so that focusing the container and then
2499                                        // calling `focus_next` descends into this group's first
2500                                        // item. Inserting it before `with_tab_group` would give the
2501                                        // container a shallower tab path than its children; with
2502                                        // sibling groups every container would then sort ahead of
2503                                        // every item, and `focus_next` from a container would jump
2504                                        // to the first item in the whole window instead of its own.
2505                                        if let Some(focus_handle) = &self.tracked_focus_handle {
2506                                            window.next_frame.tab_stops.insert(focus_handle);
2507                                        }
2508                                        if let Some(hitbox) = hitbox {
2509                                            #[cfg(debug_assertions)]
2510                                            self.paint_debug_info(
2511                                                global_id, hitbox, &style, window, cx,
2512                                            );
2513
2514                                            if let Some(drag) = cx.active_drag.as_ref() {
2515                                                if let Some(mouse_cursor) = drag.cursor_style {
2516                                                    window.set_window_cursor_style(mouse_cursor);
2517                                                }
2518                                            } else {
2519                                                if let Some(mouse_cursor) = style.mouse_cursor {
2520                                                    window.set_cursor_style(mouse_cursor, hitbox);
2521                                                }
2522                                            }
2523
2524                                            if let Some(group) = self.group.clone() {
2525                                                GroupHitboxes::push(group, hitbox.id, cx);
2526                                            }
2527
2528                                            if let Some(area) = self.window_control {
2529                                                window.insert_window_control_hitbox(
2530                                                    area,
2531                                                    hitbox.clone(),
2532                                                );
2533                                            }
2534
2535                                            self.paint_mouse_listeners(
2536                                                hitbox,
2537                                                element_state.as_mut(),
2538                                                window,
2539                                                cx,
2540                                            );
2541                                            self.paint_scroll_listener(hitbox, &style, window, cx);
2542                                        }
2543
2544                                        self.paint_keyboard_listeners(window, cx);
2545
2546                                        if window.a11y.is_active() {
2547                                            if let Some(global_id) = global_id {
2548                                                if !self.a11y_action_listeners.is_empty() {
2549                                                    let node_id = global_id.accesskit_node_id();
2550                                                    for (action, listener) in
2551                                                        self.a11y_action_listeners.drain(..)
2552                                                    {
2553                                                        window.on_a11y_action(
2554                                                            node_id, action, listener,
2555                                                        );
2556                                                    }
2557                                                }
2558                                            }
2559                                        }
2560
2561                                        f(&style, window, cx);
2562
2563                                        if let Some(_hitbox) = hitbox {
2564                                            #[cfg(any(feature = "inspector", debug_assertions))]
2565                                            window.insert_inspector_hitbox(
2566                                                _hitbox.id,
2567                                                _inspector_id,
2568                                                cx,
2569                                            );
2570
2571                                            if let Some(group) = self.group.as_ref() {
2572                                                GroupHitboxes::pop(group, cx);
2573                                            }
2574                                        }
2575                                    })
2576                                },
2577                            );
2578                        });
2579                    });
2580                });
2581
2582                ((), element_state)
2583            },
2584        );
2585    }
2586
2587    #[cfg(debug_assertions)]
2588    fn paint_debug_info(
2589        &self,
2590        global_id: Option<&GlobalElementId>,
2591        hitbox: &Hitbox,
2592        style: &Style,
2593        window: &mut Window,
2594        cx: &mut App,
2595    ) {
2596        use crate::{BorderStyle, TextAlign};
2597
2598        if let Some(global_id) = global_id
2599            && (style.debug || style.debug_below || cx.has_global::<crate::DebugBelow>())
2600            && hitbox.is_hovered(window)
2601        {
2602            const FONT_SIZE: crate::Pixels = crate::Pixels(10.);
2603            let element_id = format!("{global_id:?}");
2604            let str_len = element_id.len();
2605
2606            let render_debug_text = |window: &mut Window| {
2607                if let Some(text) = window
2608                    .text_system()
2609                    .shape_text(
2610                        &element_id,
2611                        FONT_SIZE,
2612                        &[window.text_style().to_run(str_len)],
2613                        None,
2614                        None,
2615                    )
2616                    .ok()
2617                    .and_then(|mut text| text.pop())
2618                {
2619                    text.paint(hitbox.origin, FONT_SIZE, TextAlign::Left, None, window, cx)
2620                        .ok();
2621
2622                    let text_bounds = crate::Bounds {
2623                        origin: hitbox.origin,
2624                        size: text.size(FONT_SIZE),
2625                    };
2626                    if let Some(source_location) = self.source_location
2627                        && text_bounds.contains(&window.mouse_position())
2628                        && window.modifiers().secondary()
2629                    {
2630                        let secondary_held = window.modifiers().secondary();
2631                        window.on_key_event({
2632                            move |e: &crate::ModifiersChangedEvent, _phase, window, _cx| {
2633                                if e.modifiers.secondary() != secondary_held
2634                                    && text_bounds.contains(&window.mouse_position())
2635                                {
2636                                    window.refresh();
2637                                }
2638                            }
2639                        });
2640
2641                        let was_hovered = hitbox.is_hovered(window);
2642                        let current_view = window.current_view();
2643                        window.on_mouse_event({
2644                            let hitbox = hitbox.clone();
2645                            move |_: &MouseMoveEvent, phase, window, cx| {
2646                                if phase == DispatchPhase::Capture {
2647                                    let hovered = hitbox.is_hovered(window);
2648                                    if hovered != was_hovered {
2649                                        cx.notify(current_view)
2650                                    }
2651                                }
2652                            }
2653                        });
2654
2655                        window.on_mouse_event({
2656                            let hitbox = hitbox.clone();
2657                            move |e: &crate::MouseDownEvent, phase, window, cx| {
2658                                if text_bounds.contains(&e.position)
2659                                    && phase.capture()
2660                                    && hitbox.is_hovered(window)
2661                                {
2662                                    cx.stop_propagation();
2663                                    let Ok(dir) = std::env::current_dir() else {
2664                                        return;
2665                                    };
2666
2667                                    eprintln!(
2668                                        "This element was created at:\n{}:{}:{}",
2669                                        dir.join(source_location.file()).to_string_lossy(),
2670                                        source_location.line(),
2671                                        source_location.column()
2672                                    );
2673                                }
2674                            }
2675                        });
2676                        window.paint_quad(crate::outline(
2677                            crate::Bounds {
2678                                origin: hitbox.origin
2679                                    + crate::point(crate::px(0.), FONT_SIZE - px(2.)),
2680                                size: crate::Size {
2681                                    width: text_bounds.size.width,
2682                                    height: crate::px(1.),
2683                                },
2684                            },
2685                            crate::red(),
2686                            BorderStyle::default(),
2687                        ))
2688                    }
2689                }
2690            };
2691
2692            window.with_text_style(
2693                Some(crate::TextStyleRefinement {
2694                    color: Some(crate::red()),
2695                    line_height: Some(FONT_SIZE.into()),
2696                    background_color: Some(crate::white()),
2697                    ..Default::default()
2698                }),
2699                render_debug_text,
2700            )
2701        }
2702    }
2703
2704    fn paint_mouse_listeners(
2705        &mut self,
2706        hitbox: &Hitbox,
2707        element_state: Option<&mut InteractiveElementState>,
2708        window: &mut Window,
2709        cx: &mut App,
2710    ) {
2711        let is_focused = self
2712            .tracked_focus_handle
2713            .as_ref()
2714            .map(|handle| handle.is_focused(window))
2715            .unwrap_or(false);
2716
2717        // If this element can be focused, register a mouse down listener
2718        // that will automatically transfer focus when hitting the element.
2719        // This behavior can be suppressed by using `cx.prevent_default()`.
2720        if let Some(focus_handle) = self.tracked_focus_handle.clone() {
2721            let hitbox = hitbox.clone();
2722            window.on_mouse_event(move |_: &MouseDownEvent, phase, window, cx| {
2723                if phase == DispatchPhase::Bubble
2724                    && hitbox.is_hovered(window)
2725                    && !window.default_prevented()
2726                {
2727                    window.focus(&focus_handle, cx);
2728                    // If there is a parent that is also focusable, prevent it
2729                    // from transferring focus because we already did so.
2730                    window.prevent_default();
2731                }
2732            });
2733        }
2734
2735        for listener in self.mouse_down_listeners.drain(..) {
2736            let hitbox = hitbox.clone();
2737            window.on_mouse_event(move |event: &MouseDownEvent, phase, window, cx| {
2738                listener(event, phase, &hitbox, window, cx);
2739            })
2740        }
2741
2742        for listener in self.mouse_up_listeners.drain(..) {
2743            let hitbox = hitbox.clone();
2744            window.on_mouse_event(move |event: &MouseUpEvent, phase, window, cx| {
2745                listener(event, phase, &hitbox, window, cx);
2746            })
2747        }
2748
2749        for listener in self.mouse_pressure_listeners.drain(..) {
2750            let hitbox = hitbox.clone();
2751            window.on_mouse_event(move |event: &MousePressureEvent, phase, window, cx| {
2752                listener(event, phase, &hitbox, window, cx);
2753            })
2754        }
2755
2756        for listener in self.mouse_move_listeners.drain(..) {
2757            let hitbox = hitbox.clone();
2758            window.on_mouse_event(move |event: &MouseMoveEvent, phase, window, cx| {
2759                listener(event, phase, &hitbox, window, cx);
2760            })
2761        }
2762
2763        for listener in self.mouse_exit_listeners.drain(..) {
2764            let hitbox = hitbox.clone();
2765            window.on_mouse_event(move |event: &MouseExitEvent, phase, window, cx| {
2766                listener(event, phase, &hitbox, window, cx);
2767            })
2768        }
2769
2770        for listener in self.scroll_wheel_listeners.drain(..) {
2771            let hitbox = hitbox.clone();
2772            window.on_mouse_event(move |event: &ScrollWheelEvent, phase, window, cx| {
2773                listener(event, phase, &hitbox, window, cx);
2774            })
2775        }
2776
2777        for listener in self.pinch_listeners.drain(..) {
2778            let hitbox = hitbox.clone();
2779            window.on_mouse_event(move |event: &PinchEvent, phase, window, cx| {
2780                listener(event, phase, &hitbox, window, cx);
2781            })
2782        }
2783
2784        if self.hover_style.is_some()
2785            || self.base_style.mouse_cursor.is_some()
2786            || cx.active_drag.is_some() && !self.drag_over_styles.is_empty()
2787        {
2788            let hitbox = hitbox.clone();
2789            let hover_state = self.hover_style.as_ref().and_then(|_| {
2790                element_state
2791                    .as_ref()
2792                    .and_then(|state| state.hover_state.as_ref())
2793                    .cloned()
2794            });
2795            let current_view = window.current_view();
2796
2797            window.on_mouse_event(move |_: &MouseMoveEvent, phase, window, cx| {
2798                let hovered = hitbox.is_hovered(window);
2799                let was_hovered = hover_state
2800                    .as_ref()
2801                    .is_some_and(|state| state.borrow().element);
2802                if phase == DispatchPhase::Capture && hovered != was_hovered {
2803                    if let Some(hover_state) = &hover_state {
2804                        hover_state.borrow_mut().element = hovered;
2805                        cx.notify(current_view);
2806                    }
2807                }
2808            });
2809        }
2810
2811        if let Some(group_hover) = self.group_hover_style.as_ref() {
2812            if let Some(group_hitbox_id) = GroupHitboxes::get(&group_hover.group, cx) {
2813                let hover_state = element_state
2814                    .as_ref()
2815                    .and_then(|element| element.hover_state.as_ref())
2816                    .cloned();
2817                let current_view = window.current_view();
2818
2819                window.on_mouse_event(move |_: &MouseMoveEvent, phase, window, cx| {
2820                    let group_hovered = group_hitbox_id.is_hovered(window);
2821                    let was_group_hovered = hover_state
2822                        .as_ref()
2823                        .is_some_and(|state| state.borrow().group);
2824                    if phase == DispatchPhase::Capture && group_hovered != was_group_hovered {
2825                        if let Some(hover_state) = &hover_state {
2826                            hover_state.borrow_mut().group = group_hovered;
2827                            cx.notify(current_view);
2828                        }
2829                    }
2830                });
2831            }
2832        }
2833
2834        let drag_cursor_style = self.base_style.as_ref().mouse_cursor;
2835
2836        let mut drag_listener = mem::take(&mut self.drag_listener);
2837        let drop_listeners = mem::take(&mut self.drop_listeners);
2838        let click_listeners = mem::take(&mut self.click_listeners);
2839        let aux_click_listeners = mem::take(&mut self.aux_click_listeners);
2840        let can_drop_predicate = mem::take(&mut self.can_drop_predicate);
2841
2842        if !drop_listeners.is_empty() {
2843            let hitbox = hitbox.clone();
2844            window.on_mouse_event({
2845                move |_: &MouseUpEvent, phase, window, cx| {
2846                    if let Some(drag) = &cx.active_drag
2847                        && phase == DispatchPhase::Bubble
2848                        && hitbox.is_hovered(window)
2849                    {
2850                        let drag_state_type = drag.value.as_ref().type_id();
2851                        for (drop_state_type, listener) in &drop_listeners {
2852                            if *drop_state_type == drag_state_type {
2853                                let drag = cx
2854                                    .active_drag
2855                                    .take()
2856                                    .expect("checked for type drag state type above");
2857
2858                                let mut can_drop = true;
2859                                if let Some(predicate) = &can_drop_predicate {
2860                                    can_drop = predicate(drag.value.as_ref(), window, cx);
2861                                }
2862
2863                                if can_drop {
2864                                    listener(drag.value.as_ref(), window, cx);
2865                                    window.refresh();
2866                                    cx.stop_propagation();
2867                                }
2868                            }
2869                        }
2870                    }
2871                }
2872            });
2873        }
2874
2875        if let Some(element_state) = element_state {
2876            if !click_listeners.is_empty()
2877                || !aux_click_listeners.is_empty()
2878                || drag_listener.is_some()
2879            {
2880                let pending_mouse_down = element_state
2881                    .pending_mouse_down
2882                    .get_or_insert_with(Default::default)
2883                    .clone();
2884
2885                let pending_keyboard_down = element_state
2886                    .pending_keyboard_down
2887                    .get_or_insert_with(Default::default)
2888                    .clone();
2889
2890                let clicked_state = element_state
2891                    .clicked_state
2892                    .get_or_insert_with(Default::default)
2893                    .clone();
2894
2895                window.on_mouse_event({
2896                    let pending_mouse_down = pending_mouse_down.clone();
2897                    let hitbox = hitbox.clone();
2898                    let has_aux_click_listeners = !aux_click_listeners.is_empty();
2899                    move |event: &MouseDownEvent, phase, window, _cx| {
2900                        if phase == DispatchPhase::Bubble
2901                            && (event.button == MouseButton::Left || has_aux_click_listeners)
2902                            && hitbox.is_hovered(window)
2903                        {
2904                            *pending_mouse_down.borrow_mut() = Some(event.clone());
2905                            window.refresh();
2906                        }
2907                    }
2908                });
2909
2910                window.on_mouse_event({
2911                    let pending_mouse_down = pending_mouse_down.clone();
2912                    let hitbox = hitbox.clone();
2913                    move |event: &MouseMoveEvent, phase, window, cx| {
2914                        if phase == DispatchPhase::Capture {
2915                            return;
2916                        }
2917
2918                        let mut pending_mouse_down = pending_mouse_down.borrow_mut();
2919                        if let Some(mouse_down) = pending_mouse_down.clone()
2920                            && !cx.has_active_drag()
2921                            && (event.position - mouse_down.position).magnitude() > DRAG_THRESHOLD
2922                            && let Some(listener) = drag_listener.take()
2923                            && mouse_down.button == MouseButton::Left
2924                        {
2925                            *clicked_state.borrow_mut() = ElementClickedState::default();
2926                            let cursor_offset = event.position - hitbox.origin;
2927                            let drag = (listener.render)(
2928                                listener.value.as_ref(),
2929                                cursor_offset,
2930                                window,
2931                                cx,
2932                            );
2933                            let external_payload_source =
2934                                listener.external_payload.map(|external_payload| {
2935                                    let value = listener.value.clone();
2936                                    Box::new(move |window: &mut Window, cx: &mut App| {
2937                                        external_payload(value.as_ref(), window, cx)
2938                                    })
2939                                        as ExternalDragPayloadSource
2940                                });
2941                            cx.active_drag = Some(AnyDrag {
2942                                view: drag,
2943                                value: listener.value,
2944                                cursor_offset,
2945                                cursor_style: drag_cursor_style,
2946                                external_payload_source,
2947                            });
2948                            pending_mouse_down.take();
2949                            window.refresh();
2950                            cx.stop_propagation();
2951                        }
2952                    }
2953                });
2954
2955                if is_focused {
2956                    // Record the focus generation at which an enter/space key
2957                    // down event happened on this element. The next key up
2958                    // event will be mapped to a click event if both of the
2959                    // following are true:
2960                    // - no other key events happen in between
2961                    // - the focus generation is the same (implying focus did not move)
2962                    //
2963                    // This design avoids an ABA problem that happens if you
2964                    // store the focus handle that registered the keypress.
2965                    window.on_key_event({
2966                        let pending_keyboard_down = pending_keyboard_down.clone();
2967                        move |event: &KeyDownEvent, phase, window, _cx| {
2968                            if phase.bubble() && !window.default_prevented() {
2969                                let stroke = &event.keystroke;
2970                                let is_activation_key = (stroke.key.eq("enter")
2971                                    || stroke.key.eq("space"))
2972                                    && !stroke.modifiers.modified();
2973                                *pending_keyboard_down.borrow_mut() =
2974                                    is_activation_key.then_some(window.focus_generation);
2975                            }
2976                        }
2977                    });
2978
2979                    // Press enter, space to trigger click, when the element is focused.
2980                    window.on_key_event({
2981                        let click_listeners = click_listeners.clone();
2982                        let hitbox = hitbox.clone();
2983                        move |event: &KeyUpEvent, phase, window, cx| {
2984                            if phase.bubble() && !window.default_prevented() {
2985                                let stroke = &event.keystroke;
2986                                let keyboard_button = if stroke.key.eq("enter") {
2987                                    Some(KeyboardButton::Enter)
2988                                } else if stroke.key.eq("space") {
2989                                    Some(KeyboardButton::Space)
2990                                } else {
2991                                    None
2992                                };
2993
2994                                if let Some(button) = keyboard_button
2995                                    && !stroke.modifiers.modified()
2996                                {
2997                                    let pending =
2998                                        std::mem::take(&mut *pending_keyboard_down.borrow_mut());
2999                                    if pending != Some(window.focus_generation) {
3000                                        return;
3001                                    }
3002
3003                                    let click_event = ClickEvent::Keyboard(KeyboardClickEvent {
3004                                        button,
3005                                        bounds: hitbox.bounds,
3006                                    });
3007
3008                                    for listener in &click_listeners {
3009                                        listener(&click_event, window, cx);
3010                                    }
3011                                } else {
3012                                    // Releasing any other key mid-press means
3013                                    // this isn't a clean activation, so cancel
3014                                    // the pending keydown.
3015                                    *pending_keyboard_down.borrow_mut() = None;
3016                                }
3017                            }
3018                        }
3019                    });
3020                }
3021
3022                window.on_mouse_event({
3023                    let mut captured_mouse_down = None;
3024                    let hitbox = hitbox.clone();
3025                    move |event: &MouseUpEvent, phase, window, cx| match phase {
3026                        // Clear the pending mouse down during the capture phase,
3027                        // so that it happens even if another event handler stops
3028                        // propagation.
3029                        DispatchPhase::Capture => {
3030                            let mut pending_mouse_down = pending_mouse_down.borrow_mut();
3031                            if pending_mouse_down.is_some() && hitbox.is_hovered(window) {
3032                                captured_mouse_down = pending_mouse_down.take();
3033                                window.refresh();
3034                            } else if pending_mouse_down.is_some() {
3035                                // Clear the pending mouse down event (without firing click handlers)
3036                                // if the hitbox is not being hovered.
3037                                // This avoids dragging elements that changed their position
3038                                // immediately after being clicked.
3039                                // See https://github.com/zed-industries/zed/issues/24600 for more details
3040                                pending_mouse_down.take();
3041                                window.refresh();
3042                            }
3043                        }
3044                        // Fire click handlers during the bubble phase.
3045                        DispatchPhase::Bubble => {
3046                            if let Some(mouse_down) = captured_mouse_down.take() {
3047                                let btn = mouse_down.button;
3048
3049                                let mouse_click = ClickEvent::Mouse(MouseClickEvent {
3050                                    down: mouse_down,
3051                                    up: event.clone(),
3052                                });
3053
3054                                match btn {
3055                                    MouseButton::Left => {
3056                                        for listener in &click_listeners {
3057                                            listener(&mouse_click, window, cx);
3058                                        }
3059                                    }
3060                                    _ => {
3061                                        for listener in &aux_click_listeners {
3062                                            listener(&mouse_click, window, cx);
3063                                        }
3064                                    }
3065                                }
3066                            }
3067                        }
3068                    }
3069                });
3070            }
3071
3072            if let Some(hover_listener) = self.hover_listener.take() {
3073                let was_hovered = element_state
3074                    .hover_listener_state
3075                    .get_or_insert_with(Default::default)
3076                    .clone();
3077                let has_mouse_down = element_state
3078                    .pending_mouse_down
3079                    .get_or_insert_with(Default::default)
3080                    .clone();
3081                let hover_listener = Rc::new(hover_listener);
3082                let update_hover = move |is_hovered: bool, window: &mut Window, cx: &mut App| {
3083                    let mut was_hovered = was_hovered.borrow_mut();
3084                    if is_hovered != *was_hovered {
3085                        *was_hovered = is_hovered;
3086                        drop(was_hovered);
3087                        hover_listener(&is_hovered, window, cx);
3088                    }
3089                };
3090
3091                window.on_mouse_event({
3092                    let update_hover = update_hover.clone();
3093                    let hitbox = hitbox.clone();
3094                    move |_: &MouseMoveEvent, phase, window, cx| {
3095                        if phase == DispatchPhase::Bubble {
3096                            let is_hovered = has_mouse_down.borrow().is_none()
3097                                && !cx.has_active_drag()
3098                                && hitbox.is_hovered(window);
3099                            update_hover(is_hovered, window, cx);
3100                        }
3101                    }
3102                });
3103
3104                // The pointer can leave the window without a final MouseMove, so also
3105                // clear hover on MouseExited.
3106                window.on_mouse_event(move |_: &MouseExitEvent, phase, window, cx| {
3107                    if phase == DispatchPhase::Bubble {
3108                        update_hover(false, window, cx);
3109                    }
3110                });
3111            }
3112
3113            if let Some(tooltip_builder) = self.tooltip_builder.take() {
3114                let active_tooltip = element_state
3115                    .active_tooltip
3116                    .get_or_insert_with(Default::default)
3117                    .clone();
3118                let pending_mouse_down = element_state
3119                    .pending_mouse_down
3120                    .get_or_insert_with(Default::default)
3121                    .clone();
3122
3123                let tooltip_is_hoverable = tooltip_builder.hoverable;
3124                let build_tooltip = Rc::new(move |window: &mut Window, cx: &mut App| {
3125                    Some(((tooltip_builder.build)(window, cx), tooltip_is_hoverable))
3126                });
3127                // Use bounds instead of testing hitbox since this is called during prepaint.
3128                let check_is_hovered_during_prepaint = Rc::new({
3129                    let pending_mouse_down = pending_mouse_down.clone();
3130                    let source_bounds = hitbox.bounds;
3131                    move |window: &Window| {
3132                        !window.last_input_was_keyboard()
3133                            && pending_mouse_down.borrow().is_none()
3134                            && source_bounds.contains(&window.mouse_position())
3135                    }
3136                });
3137                let check_is_hovered = Rc::new({
3138                    let hitbox = hitbox.clone();
3139                    move |window: &Window| {
3140                        pending_mouse_down.borrow().is_none() && hitbox.is_hovered(window)
3141                    }
3142                });
3143                register_tooltip_mouse_handlers(
3144                    &active_tooltip,
3145                    self.tooltip_id,
3146                    build_tooltip,
3147                    check_is_hovered,
3148                    check_is_hovered_during_prepaint,
3149                    self.tooltip_show_delay,
3150                    window,
3151                );
3152            }
3153
3154            // We unconditionally bind both the mouse up and mouse down active state handlers
3155            // Because we might not get a chance to render a frame before the mouse up event arrives.
3156            let active_state = element_state
3157                .clicked_state
3158                .get_or_insert_with(Default::default)
3159                .clone();
3160
3161            {
3162                let active_state = active_state.clone();
3163                window.on_mouse_event(move |_: &MouseUpEvent, phase, window, _cx| {
3164                    if phase == DispatchPhase::Capture && active_state.borrow().is_clicked() {
3165                        *active_state.borrow_mut() = ElementClickedState::default();
3166                        window.refresh();
3167                    }
3168                });
3169            }
3170
3171            {
3172                let active_group_hitbox = self
3173                    .group_active_style
3174                    .as_ref()
3175                    .and_then(|group_active| GroupHitboxes::get(&group_active.group, cx));
3176                let hitbox = hitbox.clone();
3177                window.on_mouse_event(move |_: &MouseDownEvent, phase, window, _cx| {
3178                    if phase == DispatchPhase::Bubble && !window.default_prevented() {
3179                        let group_hovered = active_group_hitbox
3180                            .is_some_and(|group_hitbox_id| group_hitbox_id.is_hovered(window));
3181                        let element_hovered = hitbox.is_hovered(window);
3182                        if group_hovered || element_hovered {
3183                            *active_state.borrow_mut() = ElementClickedState {
3184                                group: group_hovered,
3185                                element: element_hovered,
3186                            };
3187                            window.refresh();
3188                        }
3189                    }
3190                });
3191            }
3192        }
3193    }
3194
3195    fn paint_keyboard_listeners(&mut self, window: &mut Window, _cx: &mut App) {
3196        let key_down_listeners = mem::take(&mut self.key_down_listeners);
3197        let key_up_listeners = mem::take(&mut self.key_up_listeners);
3198        let modifiers_changed_listeners = mem::take(&mut self.modifiers_changed_listeners);
3199        let action_listeners = mem::take(&mut self.action_listeners);
3200        if let Some(context) = self.key_context.clone() {
3201            window.set_key_context(context);
3202        }
3203
3204        for listener in key_down_listeners {
3205            window.on_key_event(move |event: &KeyDownEvent, phase, window, cx| {
3206                listener(event, phase, window, cx);
3207            })
3208        }
3209
3210        for listener in key_up_listeners {
3211            window.on_key_event(move |event: &KeyUpEvent, phase, window, cx| {
3212                listener(event, phase, window, cx);
3213            })
3214        }
3215
3216        for listener in modifiers_changed_listeners {
3217            window.on_modifiers_changed(move |event: &ModifiersChangedEvent, window, cx| {
3218                listener(event, window, cx);
3219            })
3220        }
3221
3222        for (action_type, listener) in action_listeners {
3223            window.on_action(action_type, listener)
3224        }
3225    }
3226
3227    fn paint_hover_group_handler(&self, window: &mut Window, cx: &mut App) {
3228        let group_hitbox = self
3229            .group_hover_style
3230            .as_ref()
3231            .and_then(|group_hover| GroupHitboxes::get(&group_hover.group, cx));
3232
3233        if let Some(group_hitbox) = group_hitbox {
3234            let was_hovered = group_hitbox.is_hovered(window);
3235            let current_view = window.current_view();
3236            window.on_mouse_event(move |_: &MouseMoveEvent, phase, window, cx| {
3237                let hovered = group_hitbox.is_hovered(window);
3238                if phase == DispatchPhase::Capture && hovered != was_hovered {
3239                    cx.notify(current_view);
3240                }
3241            });
3242        }
3243    }
3244
3245    fn paint_scroll_listener(
3246        &self,
3247        hitbox: &Hitbox,
3248        style: &Style,
3249        window: &mut Window,
3250        _cx: &mut App,
3251    ) {
3252        if let Some(scroll_offset) = self.scroll_offset.clone() {
3253            let ongoing_scroll = self.ongoing_scroll.clone();
3254            let overflow = style.overflow;
3255            let allow_concurrent_scroll = style.allow_concurrent_scroll;
3256            let restrict_scroll_to_axis = style.restrict_scroll_to_axis;
3257            let line_height = window.line_height();
3258            let hitbox = hitbox.clone();
3259            let current_view = window.current_view();
3260            window.on_mouse_event(move |event: &ScrollWheelEvent, phase, window, cx| {
3261                if phase == DispatchPhase::Bubble && hitbox.should_handle_scroll(window) {
3262                    let mut scroll_offset = scroll_offset.borrow_mut();
3263                    let old_scroll_offset = *scroll_offset;
3264                    let mut delta = event.delta.pixel_delta(line_height);
3265
3266                    if restrict_scroll_to_axis
3267                        && event.delta.precise()
3268                        && let Some(ongoing_scroll) = &ongoing_scroll
3269                    {
3270                        ongoing_scroll
3271                            .borrow_mut()
3272                            .filter(&mut delta, event.touch_phase);
3273                    }
3274
3275                    let mut delta_x = match overflow.x {
3276                        Overflow::Scroll if !delta.x.is_zero() => delta.x,
3277                        Overflow::Scroll
3278                            if !restrict_scroll_to_axis && overflow.y != Overflow::Scroll =>
3279                        {
3280                            delta.y
3281                        }
3282                        _ => Pixels::ZERO,
3283                    };
3284                    let mut delta_y = match overflow.y {
3285                        Overflow::Scroll if !delta.y.is_zero() => delta.y,
3286                        Overflow::Scroll
3287                            if !restrict_scroll_to_axis && overflow.x != Overflow::Scroll =>
3288                        {
3289                            delta.x
3290                        }
3291                        _ => Pixels::ZERO,
3292                    };
3293                    if !allow_concurrent_scroll && !delta_x.is_zero() && !delta_y.is_zero() {
3294                        if delta_x.abs() > delta_y.abs() {
3295                            delta_y = Pixels::ZERO;
3296                        } else {
3297                            delta_x = Pixels::ZERO;
3298                        }
3299                    }
3300                    scroll_offset.y += delta_y;
3301                    scroll_offset.x += delta_x;
3302                    if *scroll_offset != old_scroll_offset {
3303                        cx.notify(current_view);
3304                    }
3305                }
3306            });
3307        }
3308    }
3309
3310    /// Compute the visual style for this element, based on the current bounds and the element's state.
3311    pub fn compute_style(
3312        &self,
3313        global_id: Option<&GlobalElementId>,
3314        hitbox: Option<&Hitbox>,
3315        window: &mut Window,
3316        cx: &mut App,
3317    ) -> Style {
3318        window.with_optional_element_state(global_id, |element_state, window| {
3319            let mut element_state =
3320                element_state.map(|element_state| element_state.unwrap_or_default());
3321            let style = self.compute_style_internal(hitbox, element_state.as_mut(), window, cx);
3322            (style, element_state)
3323        })
3324    }
3325
3326    /// Called from internal methods that have already called with_element_state.
3327    fn compute_style_internal(
3328        &self,
3329        hitbox: Option<&Hitbox>,
3330        element_state: Option<&mut InteractiveElementState>,
3331        window: &mut Window,
3332        cx: &mut App,
3333    ) -> Style {
3334        let mut style = Style::default();
3335        style.refine(&self.base_style);
3336
3337        if let Some(focus_handle) = self.tracked_focus_handle.as_ref() {
3338            if let Some(in_focus_style) = self.in_focus_style.as_ref()
3339                && focus_handle.within_focused(window, cx)
3340            {
3341                style.refine(in_focus_style);
3342            }
3343
3344            if let Some(focus_style) = self.focus_style.as_ref()
3345                && focus_handle.is_focused(window)
3346            {
3347                style.refine(focus_style);
3348            }
3349
3350            if let Some(focus_visible_style) = self.focus_visible_style.as_ref()
3351                && focus_handle.is_focused(window)
3352                && window.last_input_was_keyboard()
3353            {
3354                style.refine(focus_visible_style);
3355            }
3356        }
3357
3358        if !cx.has_active_drag() {
3359            if let Some(group_hover) = self.group_hover_style.as_ref() {
3360                let is_group_hovered =
3361                    if let Some(group_hitbox_id) = GroupHitboxes::get(&group_hover.group, cx) {
3362                        group_hitbox_id.is_hovered(window)
3363                    } else if let Some(element_state) = element_state.as_ref() {
3364                        element_state
3365                            .hover_state
3366                            .as_ref()
3367                            .map(|state| state.borrow().group)
3368                            .unwrap_or(false)
3369                    } else {
3370                        false
3371                    };
3372
3373                if is_group_hovered {
3374                    style.refine(&group_hover.style);
3375                }
3376            }
3377
3378            if let Some(hover_style) = self.hover_style.as_ref() {
3379                let is_hovered = if let Some(hitbox) = hitbox {
3380                    hitbox.is_hovered(window)
3381                } else if let Some(element_state) = element_state.as_ref() {
3382                    element_state
3383                        .hover_state
3384                        .as_ref()
3385                        .map(|state| state.borrow().element)
3386                        .unwrap_or(false)
3387                } else {
3388                    false
3389                };
3390
3391                if is_hovered {
3392                    style.refine(hover_style);
3393                }
3394            }
3395        }
3396
3397        if let Some(hitbox) = hitbox {
3398            if let Some(drag) = cx.active_drag.take() {
3399                let mut can_drop = true;
3400                if let Some(can_drop_predicate) = &self.can_drop_predicate {
3401                    can_drop = can_drop_predicate(drag.value.as_ref(), window, cx);
3402                }
3403
3404                if can_drop {
3405                    for (state_type, group_drag_style) in &self.group_drag_over_styles {
3406                        if let Some(group_hitbox_id) =
3407                            GroupHitboxes::get(&group_drag_style.group, cx)
3408                            && *state_type == drag.value.as_ref().type_id()
3409                            && group_hitbox_id.is_hovered(window)
3410                        {
3411                            style.refine(&group_drag_style.style);
3412                        }
3413                    }
3414
3415                    for (state_type, build_drag_over_style) in &self.drag_over_styles {
3416                        if *state_type == drag.value.as_ref().type_id() && hitbox.is_hovered(window)
3417                        {
3418                            style.refine(&build_drag_over_style(drag.value.as_ref(), window, cx));
3419                        }
3420                    }
3421                }
3422
3423                style.mouse_cursor = drag.cursor_style;
3424                cx.active_drag = Some(drag);
3425            }
3426        }
3427
3428        if let Some(element_state) = element_state {
3429            let clicked_state = element_state
3430                .clicked_state
3431                .get_or_insert_with(Default::default)
3432                .borrow();
3433            if clicked_state.group
3434                && let Some(group) = self.group_active_style.as_ref()
3435            {
3436                style.refine(&group.style)
3437            }
3438
3439            if let Some(active_style) = self.active_style.as_ref()
3440                && clicked_state.element
3441            {
3442                style.refine(active_style)
3443            }
3444        }
3445
3446        style
3447    }
3448
3449    pub(crate) fn write_a11y_info(&self, node: &mut accesskit::Node) {
3450        if let Some(label) = &self.aria.label {
3451            node.set_label(label.to_string());
3452        }
3453        if let Some(description) = &self.aria.description {
3454            node.set_description(description.to_string());
3455        }
3456        if let Some(keyshortcuts) = &self.aria.keyshortcuts {
3457            node.set_keyboard_shortcut(keyshortcuts.to_string());
3458        }
3459        if let Some(selected) = self.aria.selected {
3460            node.set_selected(selected);
3461        }
3462        if let Some(expanded) = self.aria.expanded {
3463            node.set_expanded(expanded);
3464        }
3465        if let Some(toggled) = self.aria.toggled {
3466            node.set_toggled(toggled);
3467        }
3468        if let Some(value) = self.aria.numeric_value {
3469            node.set_numeric_value(value);
3470        }
3471        if let Some(value) = self.aria.min_numeric_value {
3472            node.set_min_numeric_value(value);
3473        }
3474        if let Some(value) = self.aria.max_numeric_value {
3475            node.set_max_numeric_value(value);
3476        }
3477        if let Some(step) = self.aria.numeric_value_step {
3478            node.set_numeric_value_step(step);
3479        }
3480        if let Some(value) = &self.aria.value {
3481            node.set_value(value.to_string());
3482        }
3483        if let Some(placeholder) = &self.aria.placeholder {
3484            node.set_placeholder(placeholder.to_string());
3485        }
3486        if let Some(orientation) = self.aria.orientation {
3487            node.set_orientation(orientation);
3488        }
3489        if let Some(level) = self.aria.level {
3490            node.set_level(level);
3491        }
3492        if let Some(position) = self.aria.position_in_set {
3493            node.set_position_in_set(position);
3494        }
3495        if let Some(size) = self.aria.size_of_set {
3496            node.set_size_of_set(size);
3497        }
3498        if let Some(index) = self.aria.row_index {
3499            node.set_row_index(index);
3500        }
3501        if let Some(index) = self.aria.column_index {
3502            node.set_column_index(index);
3503        }
3504        if let Some(count) = self.aria.row_count {
3505            node.set_row_count(count);
3506        }
3507        if let Some(count) = self.aria.column_count {
3508            node.set_column_count(count);
3509        }
3510        if !self.click_listeners.is_empty() {
3511            node.add_action(accesskit::Action::Click);
3512        }
3513        if self.tracked_focus_handle.is_some() || self.focusable {
3514            node.add_action(accesskit::Action::Focus);
3515        }
3516        for (action, _) in &self.a11y_action_listeners {
3517            node.add_action(*action);
3518        }
3519    }
3520}
3521
3522/// The per-frame state of an interactive element. Used for tracking stateful interactions like clicks
3523/// and scroll offsets.
3524#[derive(Default)]
3525pub struct InteractiveElementState {
3526    pub(crate) focus_handle: Option<FocusHandle>,
3527    pub(crate) clicked_state: Option<Rc<RefCell<ElementClickedState>>>,
3528    pub(crate) hover_state: Option<Rc<RefCell<ElementHoverState>>>,
3529    pub(crate) hover_listener_state: Option<Rc<RefCell<bool>>>,
3530    pub(crate) pending_mouse_down: Option<Rc<RefCell<Option<MouseDownEvent>>>>,
3531    /// Set to the window's [`focus_generation`](crate::Window::focus_generation)
3532    /// when an Enter/Space keydown is received while this element is focused,
3533    /// recording that we are waiting for the matching keyup to fire a keyboard
3534    /// click. On keyup the click only fires if the stored generation still
3535    /// matches the window's current one, i.e. focus never moved during the
3536    /// press (mirroring the browser clearing a control's pressed state on
3537    /// blur). `None` means no activation key is pending.
3538    pub(crate) pending_keyboard_down: Option<Rc<RefCell<Option<u64>>>>,
3539    pub(crate) scroll_offset: Option<Rc<RefCell<Point<Pixels>>>>,
3540    ongoing_scroll: Option<Rc<RefCell<OngoingScroll>>>,
3541    pub(crate) active_tooltip: Option<Rc<RefCell<Option<ActiveTooltip>>>>,
3542}
3543
3544/// Whether or not the element or a group that contains it is clicked by the mouse.
3545#[derive(Copy, Clone, Default, Eq, PartialEq)]
3546pub struct ElementClickedState {
3547    /// True if this element's group has been clicked, false otherwise
3548    pub group: bool,
3549
3550    /// True if this element has been clicked, false otherwise
3551    pub element: bool,
3552}
3553
3554impl ElementClickedState {
3555    fn is_clicked(&self) -> bool {
3556        self.group || self.element
3557    }
3558}
3559
3560/// Whether or not the element or a group that contains it is hovered.
3561#[derive(Copy, Clone, Default, Eq, PartialEq)]
3562pub struct ElementHoverState {
3563    /// True if this element's group is hovered, false otherwise
3564    pub group: bool,
3565
3566    /// True if this element is hovered, false otherwise
3567    pub element: bool,
3568}
3569
3570pub(crate) enum ActiveTooltip {
3571    /// Currently delaying before showing the tooltip.
3572    WaitingForShow { _task: Task<()> },
3573    /// Tooltip is visible, element was hovered or for hoverable tooltips, the tooltip was hovered.
3574    Visible {
3575        tooltip: AnyTooltip,
3576        is_hoverable: bool,
3577    },
3578    /// Tooltip is visible and hoverable, but the mouse is no longer hovering. Currently delaying
3579    /// before hiding it.
3580    WaitingForHide {
3581        tooltip: AnyTooltip,
3582        _task: Task<()>,
3583    },
3584}
3585
3586pub(crate) fn clear_active_tooltip(
3587    active_tooltip: &Rc<RefCell<Option<ActiveTooltip>>>,
3588    window: &mut Window,
3589) {
3590    match active_tooltip.borrow_mut().take() {
3591        None => {}
3592        Some(ActiveTooltip::WaitingForShow { .. }) => {}
3593        Some(ActiveTooltip::Visible { .. }) => window.refresh(),
3594        Some(ActiveTooltip::WaitingForHide { .. }) => window.refresh(),
3595    }
3596}
3597
3598pub(crate) fn clear_active_tooltip_if_not_hoverable(
3599    active_tooltip: &Rc<RefCell<Option<ActiveTooltip>>>,
3600    window: &mut Window,
3601) {
3602    let should_clear = match active_tooltip.borrow().as_ref() {
3603        None => false,
3604        Some(ActiveTooltip::WaitingForShow { .. }) => false,
3605        Some(ActiveTooltip::Visible { is_hoverable, .. }) => !is_hoverable,
3606        Some(ActiveTooltip::WaitingForHide { .. }) => false,
3607    };
3608    if should_clear {
3609        active_tooltip.borrow_mut().take();
3610        window.refresh();
3611    }
3612}
3613
3614pub(crate) fn set_tooltip_on_window(
3615    active_tooltip: &Rc<RefCell<Option<ActiveTooltip>>>,
3616    window: &mut Window,
3617) -> Option<TooltipId> {
3618    let tooltip = match active_tooltip.borrow().as_ref() {
3619        None => return None,
3620        Some(ActiveTooltip::WaitingForShow { .. }) => return None,
3621        Some(ActiveTooltip::Visible { tooltip, .. }) => tooltip.clone(),
3622        Some(ActiveTooltip::WaitingForHide { tooltip, .. }) => tooltip.clone(),
3623    };
3624    Some(window.set_tooltip(tooltip))
3625}
3626
3627pub(crate) fn register_tooltip_mouse_handlers(
3628    active_tooltip: &Rc<RefCell<Option<ActiveTooltip>>>,
3629    tooltip_id: Option<TooltipId>,
3630    build_tooltip: Rc<dyn Fn(&mut Window, &mut App) -> Option<(AnyView, bool)>>,
3631    check_is_hovered: Rc<dyn Fn(&Window) -> bool>,
3632    check_is_hovered_during_prepaint: Rc<dyn Fn(&Window) -> bool>,
3633    show_delay: Option<Duration>,
3634    window: &mut Window,
3635) {
3636    let current_view = window.current_view();
3637    let show_delay = show_delay.unwrap_or(DEFAULT_TOOLTIP_SHOW_DELAY);
3638
3639    window.on_mouse_event({
3640        let active_tooltip = active_tooltip.clone();
3641        let build_tooltip = build_tooltip.clone();
3642        let check_is_hovered = check_is_hovered.clone();
3643        move |_: &MouseMoveEvent, phase, window, cx| {
3644            handle_tooltip_mouse_move(
3645                &active_tooltip,
3646                &build_tooltip,
3647                &check_is_hovered,
3648                &check_is_hovered_during_prepaint,
3649                tooltip_id,
3650                current_view,
3651                phase,
3652                show_delay,
3653                window,
3654                cx,
3655            )
3656        }
3657    });
3658
3659    window.on_mouse_event({
3660        let active_tooltip = active_tooltip.clone();
3661        move |_: &MouseDownEvent, _phase, window: &mut Window, _cx| {
3662            if !tooltip_id.is_some_and(|tooltip_id| tooltip_id.is_hovered(window)) {
3663                clear_active_tooltip_if_not_hoverable(&active_tooltip, window);
3664            }
3665        }
3666    });
3667
3668    window.on_mouse_event({
3669        let active_tooltip = active_tooltip.clone();
3670        move |_: &ScrollWheelEvent, _phase, window: &mut Window, _cx| {
3671            if !tooltip_id.is_some_and(|tooltip_id| tooltip_id.is_hovered(window)) {
3672                clear_active_tooltip_if_not_hoverable(&active_tooltip, window);
3673            }
3674        }
3675    });
3676}
3677
3678/// Handles displaying tooltips when an element is hovered.
3679///
3680/// The mouse hovering logic also relies on being called from window prepaint in order to handle the
3681/// case where the element the tooltip is on is not rendered - in that case its mouse listeners are
3682/// also not registered. During window prepaint, the hitbox information is not available, so
3683/// `check_is_hovered_during_prepaint` is used which bases the check off of the absolute bounds of
3684/// the element.
3685///
3686/// TODO: There's a minor bug due to the use of absolute bounds while checking during prepaint - it
3687/// does not know if the hitbox is occluded. In the case where a tooltip gets displayed and then
3688/// gets occluded after display, it will stick around until the mouse exits the hover bounds.
3689fn handle_tooltip_mouse_move(
3690    active_tooltip: &Rc<RefCell<Option<ActiveTooltip>>>,
3691    build_tooltip: &Rc<dyn Fn(&mut Window, &mut App) -> Option<(AnyView, bool)>>,
3692    check_is_hovered: &Rc<dyn Fn(&Window) -> bool>,
3693    check_is_hovered_during_prepaint: &Rc<dyn Fn(&Window) -> bool>,
3694    tooltip_id: Option<TooltipId>,
3695    current_view: EntityId,
3696    phase: DispatchPhase,
3697    show_delay: Duration,
3698    window: &mut Window,
3699    cx: &mut App,
3700) {
3701    // Separates logic for what mutation should occur from applying it, to avoid overlapping
3702    // RefCell borrows.
3703    enum Action {
3704        None,
3705        CancelShow,
3706        ScheduleShow,
3707        CheckVisible,
3708    }
3709
3710    let action = match active_tooltip.borrow().as_ref() {
3711        None => {
3712            let is_hovered = check_is_hovered(window);
3713            if is_hovered && phase.bubble() {
3714                Action::ScheduleShow
3715            } else {
3716                Action::None
3717            }
3718        }
3719        Some(ActiveTooltip::WaitingForShow { .. }) => {
3720            let is_hovered = check_is_hovered(window);
3721            if is_hovered {
3722                Action::None
3723            } else {
3724                Action::CancelShow
3725            }
3726        }
3727        Some(ActiveTooltip::Visible { is_hoverable, .. }) => {
3728            if phase.capture()
3729                && !check_is_hovered(window)
3730                && (!*is_hoverable
3731                    || !tooltip_id.is_some_and(|tooltip_id| tooltip_id.is_hovered(window)))
3732            {
3733                Action::CheckVisible
3734            } else {
3735                Action::None
3736            }
3737        }
3738        Some(ActiveTooltip::WaitingForHide { .. }) => {
3739            if phase.capture()
3740                && (check_is_hovered(window)
3741                    || tooltip_id.is_some_and(|tooltip_id| tooltip_id.is_hovered(window)))
3742            {
3743                Action::CheckVisible
3744            } else {
3745                Action::None
3746            }
3747        }
3748    };
3749
3750    match action {
3751        Action::None => {}
3752        Action::CancelShow => {
3753            // Cancel waiting to show tooltip when it is no longer hovered.
3754            active_tooltip.borrow_mut().take();
3755        }
3756        Action::ScheduleShow => {
3757            let delayed_show_task = window.spawn(cx, {
3758                let weak_active_tooltip = Rc::downgrade(active_tooltip);
3759                let build_tooltip = build_tooltip.clone();
3760                let check_is_hovered_during_prepaint = check_is_hovered_during_prepaint.clone();
3761                async move |cx| {
3762                    cx.background_executor().timer(show_delay).await;
3763                    let Some(active_tooltip) = weak_active_tooltip.upgrade() else {
3764                        return;
3765                    };
3766                    cx.update(|window, cx| {
3767                        let new_tooltip =
3768                            build_tooltip(window, cx).map(|(view, tooltip_is_hoverable)| {
3769                                let weak_active_tooltip = Rc::downgrade(&active_tooltip);
3770                                ActiveTooltip::Visible {
3771                                    tooltip: AnyTooltip {
3772                                        view,
3773                                        mouse_position: window.mouse_position(),
3774                                        check_visible_and_update: Rc::new(
3775                                            move |tooltip_bounds, window, cx| {
3776                                                let Some(active_tooltip) =
3777                                                    weak_active_tooltip.upgrade()
3778                                                else {
3779                                                    return false;
3780                                                };
3781                                                handle_tooltip_check_visible_and_update(
3782                                                    &active_tooltip,
3783                                                    tooltip_is_hoverable,
3784                                                    &check_is_hovered_during_prepaint,
3785                                                    tooltip_bounds,
3786                                                    window,
3787                                                    cx,
3788                                                )
3789                                            },
3790                                        ),
3791                                    },
3792                                    is_hoverable: tooltip_is_hoverable,
3793                                }
3794                            });
3795                        *active_tooltip.borrow_mut() = new_tooltip;
3796                        window.refresh();
3797                    })
3798                    .ok();
3799                }
3800            });
3801            active_tooltip
3802                .borrow_mut()
3803                .replace(ActiveTooltip::WaitingForShow {
3804                    _task: delayed_show_task,
3805                });
3806        }
3807        Action::CheckVisible => cx.notify(current_view),
3808    }
3809}
3810
3811/// Returns a callback which will be called by window prepaint to update tooltip visibility. The
3812/// purpose of doing this logic here instead of the mouse move handler is that the mouse move
3813/// handler won't get called when the element is not painted (e.g. via use of `visible_on_hover`).
3814fn handle_tooltip_check_visible_and_update(
3815    active_tooltip: &Rc<RefCell<Option<ActiveTooltip>>>,
3816    tooltip_is_hoverable: bool,
3817    check_is_hovered: &Rc<dyn Fn(&Window) -> bool>,
3818    tooltip_bounds: Bounds<Pixels>,
3819    window: &mut Window,
3820    cx: &mut App,
3821) -> bool {
3822    // Separates logic for what mutation should occur from applying it, to avoid overlapping RefCell
3823    // borrows.
3824    enum Action {
3825        None,
3826        Hide,
3827        ScheduleHide(AnyTooltip),
3828        CancelHide(AnyTooltip),
3829    }
3830
3831    let is_hovered = check_is_hovered(window)
3832        || (tooltip_is_hoverable && tooltip_bounds.contains(&window.mouse_position()));
3833    let action = match active_tooltip.borrow().as_ref() {
3834        Some(ActiveTooltip::Visible { tooltip, .. }) => {
3835            if is_hovered {
3836                Action::None
3837            } else {
3838                if tooltip_is_hoverable {
3839                    Action::ScheduleHide(tooltip.clone())
3840                } else {
3841                    Action::Hide
3842                }
3843            }
3844        }
3845        Some(ActiveTooltip::WaitingForHide { tooltip, .. }) => {
3846            if is_hovered {
3847                Action::CancelHide(tooltip.clone())
3848            } else {
3849                Action::None
3850            }
3851        }
3852        None | Some(ActiveTooltip::WaitingForShow { .. }) => Action::None,
3853    };
3854
3855    match action {
3856        Action::None => {}
3857        Action::Hide => clear_active_tooltip(active_tooltip, window),
3858        Action::ScheduleHide(tooltip) => {
3859            let delayed_hide_task = window.spawn(cx, {
3860                let weak_active_tooltip = Rc::downgrade(active_tooltip);
3861                async move |cx| {
3862                    cx.background_executor()
3863                        .timer(HOVERABLE_TOOLTIP_HIDE_DELAY)
3864                        .await;
3865                    let Some(active_tooltip) = weak_active_tooltip.upgrade() else {
3866                        return;
3867                    };
3868                    if active_tooltip.borrow_mut().take().is_some() {
3869                        cx.update(|window, _cx| window.refresh()).ok();
3870                    }
3871                }
3872            });
3873            active_tooltip
3874                .borrow_mut()
3875                .replace(ActiveTooltip::WaitingForHide {
3876                    tooltip,
3877                    _task: delayed_hide_task,
3878                });
3879        }
3880        Action::CancelHide(tooltip) => {
3881            // Cancel waiting to hide tooltip when it becomes hovered.
3882            active_tooltip.borrow_mut().replace(ActiveTooltip::Visible {
3883                tooltip,
3884                is_hoverable: true,
3885            });
3886        }
3887    }
3888
3889    active_tooltip.borrow().is_some()
3890}
3891
3892#[derive(Default)]
3893pub(crate) struct GroupHitboxes(HashMap<SharedString, SmallVec<[HitboxId; 1]>>);
3894
3895impl Global for GroupHitboxes {}
3896
3897impl GroupHitboxes {
3898    pub fn get(name: &SharedString, cx: &mut App) -> Option<HitboxId> {
3899        cx.default_global::<Self>()
3900            .0
3901            .get(name)
3902            .and_then(|bounds_stack| bounds_stack.last())
3903            .cloned()
3904    }
3905
3906    pub fn push(name: SharedString, hitbox_id: HitboxId, cx: &mut App) {
3907        cx.default_global::<Self>()
3908            .0
3909            .entry(name)
3910            .or_default()
3911            .push(hitbox_id);
3912    }
3913
3914    pub fn pop(name: &SharedString, cx: &mut App) {
3915        cx.default_global::<Self>().0.get_mut(name).unwrap().pop();
3916    }
3917}
3918
3919/// A wrapper around an element that can store state, produced after assigning an ElementId.
3920pub struct Stateful<E> {
3921    pub(crate) element: E,
3922}
3923
3924impl<E> Styled for Stateful<E>
3925where
3926    E: Styled,
3927{
3928    fn style(&mut self) -> &mut StyleRefinement {
3929        self.element.style()
3930    }
3931}
3932
3933impl<E> StatefulInteractiveElement for Stateful<E>
3934where
3935    E: Element,
3936    Self: InteractiveElement,
3937{
3938}
3939
3940impl<E> InteractiveElement for Stateful<E>
3941where
3942    E: InteractiveElement,
3943{
3944    fn interactivity(&mut self) -> &mut Interactivity {
3945        self.element.interactivity()
3946    }
3947}
3948
3949impl<E> Element for Stateful<E>
3950where
3951    E: Element,
3952{
3953    type RequestLayoutState = E::RequestLayoutState;
3954    type PrepaintState = E::PrepaintState;
3955
3956    fn id(&self) -> Option<ElementId> {
3957        self.element.id()
3958    }
3959
3960    fn source_location(&self) -> Option<&'static core::panic::Location<'static>> {
3961        self.element.source_location()
3962    }
3963
3964    fn a11y_role(&self) -> Option<accesskit::Role> {
3965        self.element.a11y_role()
3966    }
3967
3968    fn write_a11y_info(&self, node: &mut accesskit::Node) {
3969        self.element.write_a11y_info(node);
3970    }
3971
3972    fn a11y_synthetic_children(
3973        &mut self,
3974        prepaint: &mut Self::PrepaintState,
3975        builder: &mut crate::A11ySubtreeBuilder,
3976    ) {
3977        self.element.a11y_synthetic_children(prepaint, builder);
3978    }
3979
3980    fn request_layout(
3981        &mut self,
3982        id: Option<&GlobalElementId>,
3983        inspector_id: Option<&InspectorElementId>,
3984        window: &mut Window,
3985        cx: &mut App,
3986    ) -> (LayoutId, Self::RequestLayoutState) {
3987        self.element.request_layout(id, inspector_id, window, cx)
3988    }
3989
3990    fn prepaint(
3991        &mut self,
3992        id: Option<&GlobalElementId>,
3993        inspector_id: Option<&InspectorElementId>,
3994        bounds: Bounds<Pixels>,
3995        state: &mut Self::RequestLayoutState,
3996        window: &mut Window,
3997        cx: &mut App,
3998    ) -> E::PrepaintState {
3999        self.element
4000            .prepaint(id, inspector_id, bounds, state, window, cx)
4001    }
4002
4003    fn paint(
4004        &mut self,
4005        id: Option<&GlobalElementId>,
4006        inspector_id: Option<&InspectorElementId>,
4007        bounds: Bounds<Pixels>,
4008        request_layout: &mut Self::RequestLayoutState,
4009        prepaint: &mut Self::PrepaintState,
4010        window: &mut Window,
4011        cx: &mut App,
4012    ) {
4013        self.element.paint(
4014            id,
4015            inspector_id,
4016            bounds,
4017            request_layout,
4018            prepaint,
4019            window,
4020            cx,
4021        );
4022    }
4023}
4024
4025impl<E> IntoElement for Stateful<E>
4026where
4027    E: Element,
4028{
4029    type Element = Self;
4030
4031    fn into_element(self) -> Self::Element {
4032        self
4033    }
4034}
4035
4036impl<E> ParentElement for Stateful<E>
4037where
4038    E: ParentElement,
4039{
4040    fn extend(&mut self, elements: impl IntoIterator<Item = AnyElement>) {
4041        self.element.extend(elements)
4042    }
4043}
4044
4045/// Represents an element that can be scrolled *to* in its parent element.
4046/// Contrary to [ScrollHandle::scroll_to_active_item], an anchored element does not have to be an immediate child of the parent.
4047#[derive(Clone)]
4048pub struct ScrollAnchor {
4049    handle: ScrollHandle,
4050    last_origin: Rc<RefCell<Point<Pixels>>>,
4051}
4052
4053impl ScrollAnchor {
4054    /// Creates a [ScrollAnchor] associated with a given [ScrollHandle].
4055    pub fn for_handle(handle: ScrollHandle) -> Self {
4056        Self {
4057            handle,
4058            last_origin: Default::default(),
4059        }
4060    }
4061    /// Request scroll to this item on the next frame.
4062    pub fn scroll_to(&self, window: &mut Window, _cx: &mut App) {
4063        let this = self.clone();
4064
4065        window.on_next_frame(move |_, _| {
4066            let viewport_bounds = this.handle.bounds();
4067            let self_bounds = *this.last_origin.borrow();
4068            this.handle.set_offset(viewport_bounds.origin - self_bounds);
4069        });
4070    }
4071}
4072
4073#[derive(Default, Debug)]
4074struct ScrollHandleState {
4075    offset: Rc<RefCell<Point<Pixels>>>,
4076    ongoing_scroll: Rc<RefCell<OngoingScroll>>,
4077    bounds: Bounds<Pixels>,
4078    max_offset: Point<Pixels>,
4079    child_bounds: Vec<Bounds<Pixels>>,
4080    scroll_to_bottom: bool,
4081    overflow: Point<Overflow>,
4082    active_item: Option<ScrollActiveItem>,
4083}
4084
4085#[derive(Default, Debug, Clone, Copy)]
4086struct ScrollActiveItem {
4087    index: usize,
4088    strategy: ScrollStrategy,
4089}
4090
4091#[derive(Default, Debug, Clone, Copy)]
4092enum ScrollStrategy {
4093    #[default]
4094    FirstVisible,
4095    Top,
4096}
4097
4098/// A handle to the scrollable aspects of an element.
4099/// Used for accessing scroll state, like the current scroll offset,
4100/// and for mutating the scroll state, like scrolling to a specific child.
4101#[derive(Clone, Debug)]
4102pub struct ScrollHandle(Rc<RefCell<ScrollHandleState>>);
4103
4104impl Default for ScrollHandle {
4105    fn default() -> Self {
4106        Self::new()
4107    }
4108}
4109
4110impl ScrollHandle {
4111    /// Construct a new scroll handle.
4112    pub fn new() -> Self {
4113        Self(Rc::default())
4114    }
4115
4116    /// Get the current scroll offset.
4117    pub fn offset(&self) -> Point<Pixels> {
4118        *self.0.borrow().offset.borrow()
4119    }
4120
4121    /// Get the maximum scroll offset.
4122    pub fn max_offset(&self) -> Point<Pixels> {
4123        self.0.borrow().max_offset
4124    }
4125
4126    /// Get the top child that's scrolled into view.
4127    pub fn top_item(&self) -> usize {
4128        let state = self.0.borrow();
4129        let top = state.bounds.top() - state.offset.borrow().y;
4130
4131        match state.child_bounds.binary_search_by(|bounds| {
4132            if top < bounds.top() {
4133                Ordering::Greater
4134            } else if top > bounds.bottom() {
4135                Ordering::Less
4136            } else {
4137                Ordering::Equal
4138            }
4139        }) {
4140            Ok(ix) => ix,
4141            Err(ix) => ix.min(state.child_bounds.len().saturating_sub(1)),
4142        }
4143    }
4144
4145    /// Get the bottom child that's scrolled into view.
4146    pub fn bottom_item(&self) -> usize {
4147        let state = self.0.borrow();
4148        let bottom = state.bounds.bottom() - state.offset.borrow().y;
4149
4150        match state.child_bounds.binary_search_by(|bounds| {
4151            if bottom < bounds.top() {
4152                Ordering::Greater
4153            } else if bottom > bounds.bottom() {
4154                Ordering::Less
4155            } else {
4156                Ordering::Equal
4157            }
4158        }) {
4159            Ok(ix) => ix,
4160            Err(ix) => ix.min(state.child_bounds.len().saturating_sub(1)),
4161        }
4162    }
4163
4164    /// Return the bounds into which this child is painted
4165    pub fn bounds(&self) -> Bounds<Pixels> {
4166        self.0.borrow().bounds
4167    }
4168
4169    /// Get the bounds for a specific child.
4170    pub fn bounds_for_item(&self, ix: usize) -> Option<Bounds<Pixels>> {
4171        self.0.borrow().child_bounds.get(ix).cloned()
4172    }
4173
4174    /// Update [ScrollHandleState]'s active item for scrolling to in prepaint
4175    pub fn scroll_to_item(&self, ix: usize) {
4176        let mut state = self.0.borrow_mut();
4177        state.active_item = Some(ScrollActiveItem {
4178            index: ix,
4179            strategy: ScrollStrategy::default(),
4180        });
4181    }
4182
4183    /// Update [ScrollHandleState]'s active item for scrolling to in prepaint
4184    /// This scrolls the minimal amount to ensure that the child is the first visible element
4185    pub fn scroll_to_top_of_item(&self, ix: usize) {
4186        let mut state = self.0.borrow_mut();
4187        state.active_item = Some(ScrollActiveItem {
4188            index: ix,
4189            strategy: ScrollStrategy::Top,
4190        });
4191    }
4192
4193    /// Scrolls the minimal amount to either ensure that the child is
4194    /// fully visible or the top element of the view depends on the
4195    /// scroll strategy
4196    fn scroll_to_active_item(&self) {
4197        let mut state = self.0.borrow_mut();
4198
4199        let Some(active_item) = state.active_item else {
4200            return;
4201        };
4202
4203        let active_item = match state.child_bounds.get(active_item.index) {
4204            Some(bounds) => {
4205                let mut scroll_offset = state.offset.borrow_mut();
4206
4207                match active_item.strategy {
4208                    ScrollStrategy::FirstVisible => {
4209                        if state.overflow.y == Overflow::Scroll {
4210                            let child_height = bounds.size.height;
4211                            let viewport_height = state.bounds.size.height;
4212                            if child_height > viewport_height {
4213                                scroll_offset.y = state.bounds.top() - bounds.top();
4214                            } else if bounds.top() + scroll_offset.y < state.bounds.top() {
4215                                scroll_offset.y = state.bounds.top() - bounds.top();
4216                            } else if bounds.bottom() + scroll_offset.y > state.bounds.bottom() {
4217                                scroll_offset.y = state.bounds.bottom() - bounds.bottom();
4218                            }
4219                        }
4220                    }
4221                    ScrollStrategy::Top => {
4222                        scroll_offset.y = state.bounds.top() - bounds.top();
4223                    }
4224                }
4225
4226                if state.overflow.x == Overflow::Scroll {
4227                    let child_width = bounds.size.width;
4228                    let viewport_width = state.bounds.size.width;
4229                    if child_width > viewport_width {
4230                        scroll_offset.x = state.bounds.left() - bounds.left();
4231                    } else if bounds.left() + scroll_offset.x < state.bounds.left() {
4232                        scroll_offset.x = state.bounds.left() - bounds.left();
4233                    } else if bounds.right() + scroll_offset.x > state.bounds.right() {
4234                        scroll_offset.x = state.bounds.right() - bounds.right();
4235                    }
4236                }
4237                None
4238            }
4239            None => Some(active_item),
4240        };
4241        state.active_item = active_item;
4242    }
4243
4244    /// Scrolls to the bottom.
4245    pub fn scroll_to_bottom(&self) {
4246        let mut state = self.0.borrow_mut();
4247        state.scroll_to_bottom = true;
4248    }
4249
4250    /// Set the offset explicitly. The offset is the distance from the top left of the
4251    /// parent container to the top left of the first child.
4252    /// As you scroll further down the offset becomes more negative.
4253    pub fn set_offset(&self, mut position: Point<Pixels>) {
4254        let state = self.0.borrow();
4255        *state.offset.borrow_mut() = position;
4256    }
4257
4258    /// Get the logical scroll top, based on a child index and a pixel offset.
4259    pub fn logical_scroll_top(&self) -> (usize, Pixels) {
4260        let ix = self.top_item();
4261        let state = self.0.borrow();
4262
4263        if let Some(child_bounds) = state.child_bounds.get(ix) {
4264            (
4265                ix,
4266                child_bounds.top() + state.offset.borrow().y - state.bounds.top(),
4267            )
4268        } else {
4269            (ix, px(0.))
4270        }
4271    }
4272
4273    /// Get the logical scroll bottom, based on a child index and a pixel offset.
4274    pub fn logical_scroll_bottom(&self) -> (usize, Pixels) {
4275        let ix = self.bottom_item();
4276        let state = self.0.borrow();
4277
4278        if let Some(child_bounds) = state.child_bounds.get(ix) {
4279            (
4280                ix,
4281                child_bounds.bottom() + state.offset.borrow().y - state.bounds.bottom(),
4282            )
4283        } else {
4284            (ix, px(0.))
4285        }
4286    }
4287
4288    /// Get the count of children for scrollable item.
4289    pub fn children_count(&self) -> usize {
4290        self.0.borrow().child_bounds.len()
4291    }
4292}
4293
4294#[cfg(test)]
4295mod tests {
4296    use super::*;
4297    use crate::{
4298        AnyWindowHandle, AppContext as _, Context, InputEvent, Keystroke, MouseMoveEvent,
4299        TestAppContext, canvas, util::FluentBuilder as _,
4300    };
4301    use std::{cell::Cell, rc::Weak};
4302
4303    struct GroupHoverTestView {
4304        render_count: Rc<Cell<usize>>,
4305        anonymous_paint_count: Rc<Cell<usize>>,
4306        stateful_width: Rc<Cell<Pixels>>,
4307    }
4308
4309    impl Render for GroupHoverTestView {
4310        fn render(&mut self, _window: &mut Window, _cx: &mut Context<Self>) -> impl IntoElement {
4311            self.render_count.set(self.render_count.get() + 1);
4312            let anonymous_paint_count = self.anonymous_paint_count.clone();
4313            let stateful_width = self.stateful_width.clone();
4314            div().size_full().child(
4315                div()
4316                    .ml(px(20.))
4317                    .mt(px(20.))
4318                    .size(px(50.))
4319                    .relative()
4320                    .group("hover-group")
4321                    .child(
4322                        div()
4323                            .absolute()
4324                            .size_full()
4325                            .invisible()
4326                            .group_hover("hover-group", |style| style.visible())
4327                            .child(canvas(
4328                                |_, _, _| {},
4329                                move |_, _, _, _| {
4330                                    anonymous_paint_count.set(anonymous_paint_count.get() + 1)
4331                                },
4332                            )),
4333                    )
4334                    .child(
4335                        div()
4336                            .id("stateful-group-hover-target")
4337                            .absolute()
4338                            .top_0()
4339                            .left_0()
4340                            .size(px(10.))
4341                            .group_hover("hover-group", |style| style.size(px(20.)))
4342                            .child(canvas(
4343                                move |bounds, _, _| stateful_width.set(bounds.size.width),
4344                                |_, _, _, _| {},
4345                            )),
4346                    ),
4347            )
4348        }
4349    }
4350
4351    #[gpui::test]
4352    fn group_hover_styles_update_only_on_transitions(cx: &mut TestAppContext) {
4353        let render_count = Rc::new(Cell::new(0));
4354        let anonymous_paint_count = Rc::new(Cell::new(0));
4355        let stateful_width = Rc::new(Cell::new(px(0.)));
4356        let window = cx.add_window({
4357            let render_count = render_count.clone();
4358            let anonymous_paint_count = anonymous_paint_count.clone();
4359            let stateful_width = stateful_width.clone();
4360            move |_, _| GroupHoverTestView {
4361                render_count,
4362                anonymous_paint_count,
4363                stateful_width,
4364            }
4365        });
4366        let window = AnyWindowHandle::from(window);
4367
4368        cx.update_window(window, |_, window, cx| window.draw(cx).clear(cx))
4369            .unwrap();
4370        assert_eq!(anonymous_paint_count.get(), 0);
4371        assert_eq!(stateful_width.get(), px(10.));
4372
4373        let move_mouse = |cx: &mut TestAppContext, position| {
4374            cx.update_window(window, |_, window, cx| {
4375                window.simulate_mouse_move(position, cx)
4376            })
4377            .unwrap();
4378        };
4379
4380        let initial_render_count = render_count.get();
4381        move_mouse(cx, point(px(25.), px(25.)));
4382        assert_eq!(render_count.get(), initial_render_count + 1);
4383        assert_eq!(anonymous_paint_count.get(), 1);
4384        assert_eq!(stateful_width.get(), px(20.));
4385
4386        move_mouse(cx, point(px(30.), px(30.)));
4387        assert_eq!(render_count.get(), initial_render_count + 1);
4388        assert_eq!(anonymous_paint_count.get(), 1);
4389        assert_eq!(stateful_width.get(), px(20.));
4390
4391        move_mouse(cx, point(px(5.), px(5.)));
4392        assert_eq!(render_count.get(), initial_render_count + 2);
4393        assert_eq!(anonymous_paint_count.get(), 1);
4394        assert_eq!(stateful_width.get(), px(10.));
4395
4396        move_mouse(cx, point(px(10.), px(10.)));
4397        assert_eq!(render_count.get(), initial_render_count + 2);
4398        assert_eq!(anonymous_paint_count.get(), 1);
4399        assert_eq!(stateful_width.get(), px(10.));
4400    }
4401
4402    struct TestTooltipView;
4403
4404    impl Render for TestTooltipView {
4405        fn render(&mut self, _window: &mut Window, _cx: &mut Context<Self>) -> impl IntoElement {
4406            div().w(px(20.)).h(px(20.)).child("tooltip")
4407        }
4408    }
4409
4410    type CapturedActiveTooltip = Rc<RefCell<Option<Weak<RefCell<Option<ActiveTooltip>>>>>>;
4411
4412    struct TooltipCaptureElement {
4413        child: AnyElement,
4414        captured_active_tooltip: CapturedActiveTooltip,
4415    }
4416
4417    impl IntoElement for TooltipCaptureElement {
4418        type Element = Self;
4419
4420        fn into_element(self) -> Self::Element {
4421            self
4422        }
4423    }
4424
4425    impl Element for TooltipCaptureElement {
4426        type RequestLayoutState = ();
4427        type PrepaintState = ();
4428
4429        fn id(&self) -> Option<ElementId> {
4430            None
4431        }
4432
4433        fn source_location(&self) -> Option<&'static core::panic::Location<'static>> {
4434            None
4435        }
4436
4437        fn request_layout(
4438            &mut self,
4439            _id: Option<&GlobalElementId>,
4440            _inspector_id: Option<&InspectorElementId>,
4441            window: &mut Window,
4442            cx: &mut App,
4443        ) -> (LayoutId, Self::RequestLayoutState) {
4444            (self.child.request_layout(window, cx), ())
4445        }
4446
4447        fn prepaint(
4448            &mut self,
4449            _id: Option<&GlobalElementId>,
4450            _inspector_id: Option<&InspectorElementId>,
4451            _bounds: Bounds<Pixels>,
4452            _request_layout: &mut Self::RequestLayoutState,
4453            window: &mut Window,
4454            cx: &mut App,
4455        ) -> Self::PrepaintState {
4456            self.child.prepaint(window, cx);
4457        }
4458
4459        fn paint(
4460            &mut self,
4461            _id: Option<&GlobalElementId>,
4462            _inspector_id: Option<&InspectorElementId>,
4463            _bounds: Bounds<Pixels>,
4464            _request_layout: &mut Self::RequestLayoutState,
4465            _prepaint: &mut Self::PrepaintState,
4466            window: &mut Window,
4467            cx: &mut App,
4468        ) {
4469            self.child.paint(window, cx);
4470            window.with_global_id("target".into(), |global_id, window| {
4471                window.with_element_state::<InteractiveElementState, _>(
4472                    global_id,
4473                    |state, _window| {
4474                        let state = state.unwrap();
4475                        *self.captured_active_tooltip.borrow_mut() =
4476                            state.active_tooltip.as_ref().map(Rc::downgrade);
4477                        ((), state)
4478                    },
4479                )
4480            });
4481        }
4482    }
4483
4484    struct TooltipOwner {
4485        captured_active_tooltip: CapturedActiveTooltip,
4486        show_delay_override: Option<Duration>,
4487    }
4488
4489    impl Render for TooltipOwner {
4490        fn render(&mut self, _window: &mut Window, _cx: &mut Context<Self>) -> impl IntoElement {
4491            TooltipCaptureElement {
4492                child: div()
4493                    .size_full()
4494                    .child(
4495                        div()
4496                            .id("target")
4497                            .w(px(50.))
4498                            .h(px(50.))
4499                            .tooltip(|_, cx| cx.new(|_| TestTooltipView).into())
4500                            .when_some(self.show_delay_override, |this, delay| {
4501                                this.tooltip_show_delay(delay)
4502                            }),
4503                    )
4504                    .into_any_element(),
4505                captured_active_tooltip: self.captured_active_tooltip.clone(),
4506            }
4507        }
4508    }
4509
4510    #[test]
4511    fn scroll_handle_aligns_wide_children_to_left_edge() {
4512        let handle = ScrollHandle::new();
4513        {
4514            let mut state = handle.0.borrow_mut();
4515            state.bounds = Bounds::new(point(px(0.), px(0.)), size(px(80.), px(20.)));
4516            state.child_bounds = vec![Bounds::new(point(px(25.), px(0.)), size(px(200.), px(20.)))];
4517            state.overflow.x = Overflow::Scroll;
4518            state.active_item = Some(ScrollActiveItem {
4519                index: 0,
4520                strategy: ScrollStrategy::default(),
4521            });
4522        }
4523
4524        handle.scroll_to_active_item();
4525
4526        assert_eq!(handle.offset().x, px(-25.));
4527    }
4528
4529    #[test]
4530    fn scroll_handle_aligns_tall_children_to_top_edge() {
4531        let handle = ScrollHandle::new();
4532        {
4533            let mut state = handle.0.borrow_mut();
4534            state.bounds = Bounds::new(point(px(0.), px(0.)), size(px(20.), px(80.)));
4535            state.child_bounds = vec![Bounds::new(point(px(0.), px(25.)), size(px(20.), px(200.)))];
4536            state.overflow.y = Overflow::Scroll;
4537            state.active_item = Some(ScrollActiveItem {
4538                index: 0,
4539                strategy: ScrollStrategy::default(),
4540            });
4541        }
4542
4543        handle.scroll_to_active_item();
4544
4545        assert_eq!(handle.offset().y, px(-25.));
4546    }
4547
4548    fn setup_tooltip_owner_test(
4549        show_delay_override: Option<Duration>,
4550    ) -> (
4551        TestAppContext,
4552        crate::AnyWindowHandle,
4553        CapturedActiveTooltip,
4554    ) {
4555        let mut test_app = TestAppContext::single();
4556        let captured_active_tooltip: CapturedActiveTooltip = Rc::new(RefCell::new(None));
4557        let window = test_app.add_window({
4558            let captured_active_tooltip = captured_active_tooltip.clone();
4559            move |_, _| TooltipOwner {
4560                captured_active_tooltip,
4561                show_delay_override,
4562            }
4563        });
4564        let any_window = window.into();
4565
4566        test_app
4567            .update_window(any_window, |_, window, cx| {
4568                window.draw(cx).clear(cx);
4569            })
4570            .unwrap();
4571
4572        test_app
4573            .update_window(any_window, |_, window, cx| {
4574                window.dispatch_event(
4575                    MouseMoveEvent {
4576                        position: point(px(10.), px(10.)),
4577                        modifiers: Default::default(),
4578                        pressed_button: None,
4579                    }
4580                    .to_platform_input(),
4581                    cx,
4582                );
4583            })
4584            .unwrap();
4585
4586        test_app
4587            .update_window(any_window, |_, window, cx| {
4588                window.draw(cx).clear(cx);
4589            })
4590            .unwrap();
4591
4592        (test_app, any_window, captured_active_tooltip)
4593    }
4594
4595    #[test]
4596    fn tooltip_waiting_for_show_is_released_when_its_owner_disappears() {
4597        let (mut test_app, any_window, captured_active_tooltip) = setup_tooltip_owner_test(None);
4598
4599        let weak_active_tooltip = captured_active_tooltip.borrow().clone().unwrap();
4600        let active_tooltip = weak_active_tooltip.upgrade().unwrap();
4601        assert!(matches!(
4602            active_tooltip.borrow().as_ref(),
4603            Some(ActiveTooltip::WaitingForShow { .. })
4604        ));
4605
4606        test_app
4607            .update_window(any_window, |_, window, _| {
4608                window.remove_window();
4609            })
4610            .unwrap();
4611        test_app.run_until_parked();
4612        drop(active_tooltip);
4613
4614        assert!(weak_active_tooltip.upgrade().is_none());
4615    }
4616
4617    #[test]
4618    fn tooltip_respects_custom_show_delay() {
4619        let extra_delay = Duration::from_secs(1);
4620        let show_delay_override = DEFAULT_TOOLTIP_SHOW_DELAY + extra_delay;
4621        let (mut test_app, _any_window, captured_active_tooltip) =
4622            setup_tooltip_owner_test(Some(show_delay_override));
4623
4624        let weak_active_tooltip = captured_active_tooltip.borrow().clone().unwrap();
4625        let active_tooltip = weak_active_tooltip.upgrade().unwrap();
4626
4627        test_app
4628            .dispatcher
4629            .advance_clock(DEFAULT_TOOLTIP_SHOW_DELAY);
4630        test_app.run_until_parked();
4631
4632        assert!(matches!(
4633            active_tooltip.borrow().as_ref(),
4634            Some(ActiveTooltip::WaitingForShow { .. })
4635        ));
4636
4637        test_app.dispatcher.advance_clock(extra_delay);
4638        test_app.run_until_parked();
4639
4640        assert!(matches!(
4641            active_tooltip.borrow().as_ref(),
4642            Some(ActiveTooltip::Visible { .. })
4643        ));
4644    }
4645
4646    #[test]
4647    fn tooltip_is_released_when_its_owner_disappears() {
4648        let (mut test_app, any_window, captured_active_tooltip) = setup_tooltip_owner_test(None);
4649
4650        let weak_active_tooltip = captured_active_tooltip.borrow().clone().unwrap();
4651        let active_tooltip = weak_active_tooltip.upgrade().unwrap();
4652
4653        test_app
4654            .dispatcher
4655            .advance_clock(DEFAULT_TOOLTIP_SHOW_DELAY);
4656        test_app.run_until_parked();
4657
4658        assert!(matches!(
4659            active_tooltip.borrow().as_ref(),
4660            Some(ActiveTooltip::Visible { .. })
4661        ));
4662
4663        test_app
4664            .update_window(any_window, |_, window, _| {
4665                window.remove_window();
4666            })
4667            .unwrap();
4668        test_app.run_until_parked();
4669        drop(active_tooltip);
4670
4671        assert!(weak_active_tooltip.upgrade().is_none());
4672    }
4673
4674    #[test]
4675    fn tooltip_hides_after_mouse_leaves_origin() {
4676        let (mut test_app, any_window, captured_active_tooltip) = setup_tooltip_owner_test(None);
4677
4678        let weak_active_tooltip = captured_active_tooltip.borrow().clone().unwrap();
4679        let active_tooltip = weak_active_tooltip.upgrade().unwrap();
4680
4681        test_app
4682            .dispatcher
4683            .advance_clock(DEFAULT_TOOLTIP_SHOW_DELAY);
4684        test_app.run_until_parked();
4685
4686        assert!(matches!(
4687            active_tooltip.borrow().as_ref(),
4688            Some(ActiveTooltip::Visible { .. })
4689        ));
4690
4691        test_app
4692            .update_window(any_window, |_, window, cx| {
4693                window.dispatch_event(
4694                    MouseMoveEvent {
4695                        position: point(px(75.), px(75.)),
4696                        modifiers: Default::default(),
4697                        pressed_button: None,
4698                    }
4699                    .to_platform_input(),
4700                    cx,
4701                );
4702            })
4703            .unwrap();
4704
4705        assert!(active_tooltip.borrow().is_none());
4706    }
4707
4708    struct MouseDownOutOwner {
4709        mouse_down_out_count: Rc<RefCell<usize>>,
4710    }
4711
4712    impl Render for MouseDownOutOwner {
4713        fn render(&mut self, _window: &mut Window, _cx: &mut Context<Self>) -> impl IntoElement {
4714            let mouse_down_out_count = self.mouse_down_out_count.clone();
4715            div()
4716                .size_full()
4717                .child(div().id("target").w(px(50.)).h(px(50.)).on_mouse_down_out(
4718                    move |_, _, _| {
4719                        *mouse_down_out_count.borrow_mut() += 1;
4720                    },
4721                ))
4722        }
4723    }
4724
4725    #[test]
4726    fn mouse_down_out_is_suppressed_while_window_prompt_is_active() {
4727        let mut test_app = TestAppContext::single();
4728        let mouse_down_out_count = Rc::new(RefCell::new(0));
4729        let window = test_app.add_window({
4730            let mouse_down_out_count = mouse_down_out_count.clone();
4731            move |_, _| MouseDownOutOwner {
4732                mouse_down_out_count,
4733            }
4734        });
4735        let any_window: AnyWindowHandle = window.into();
4736
4737        fn dispatch_mouse_down_outside_target(
4738            test_app: &mut TestAppContext,
4739            any_window: AnyWindowHandle,
4740        ) {
4741            test_app
4742                .update_window(any_window, |_, window, cx| {
4743                    window.dispatch_event(
4744                        MouseDownEvent {
4745                            position: point(px(75.), px(75.)),
4746                            button: MouseButton::Left,
4747                            modifiers: Default::default(),
4748                            click_count: 1,
4749                            first_mouse: false,
4750                        }
4751                        .to_platform_input(),
4752                        cx,
4753                    );
4754                })
4755                .unwrap();
4756        }
4757
4758        test_app
4759            .update_window(any_window, |_, window, cx| {
4760                window.draw(cx).clear(cx);
4761            })
4762            .unwrap();
4763
4764        dispatch_mouse_down_outside_target(&mut test_app, any_window);
4765        assert_eq!(
4766            *mouse_down_out_count.borrow(),
4767            1,
4768            "mouse down outside the element should fire mouse-down-out listeners"
4769        );
4770
4771        test_app
4772            .update_window(any_window, |_, window, cx| {
4773                cx.set_prompt_builder(crate::fallback_prompt_renderer);
4774                let _receiver =
4775                    window.prompt(crate::PromptLevel::Warning, "message", None, &["Ok"], cx);
4776                assert!(window.has_active_prompt());
4777                window.draw(cx).clear(cx);
4778            })
4779            .unwrap();
4780
4781        dispatch_mouse_down_outside_target(&mut test_app, any_window);
4782        assert_eq!(
4783            *mouse_down_out_count.borrow(),
4784            1,
4785            "mouse down over an active prompt should not fire mouse-down-out listeners"
4786        );
4787    }
4788
4789    #[test]
4790    fn test_write_a11y_info_string_and_numeric_properties() {
4791        let mut interactivity = Interactivity::default();
4792        interactivity.aria.label = Some("Buffer Font Size".into());
4793        interactivity.aria.value = Some("15".into());
4794        interactivity.aria.placeholder = Some("Search".into());
4795        interactivity.aria.numeric_value = Some(15.0);
4796        interactivity.aria.min_numeric_value = Some(6.0);
4797        interactivity.aria.max_numeric_value = Some(72.0);
4798        interactivity.aria.numeric_value_step = Some(1.0);
4799
4800        let mut node = accesskit::Node::new(accesskit::Role::SpinButton);
4801        interactivity.write_a11y_info(&mut node);
4802
4803        assert_eq!(node.label(), Some("Buffer Font Size"));
4804        assert_eq!(node.value(), Some("15"));
4805        assert_eq!(node.placeholder(), Some("Search"));
4806        assert_eq!(node.numeric_value(), Some(15.0));
4807        assert_eq!(node.min_numeric_value(), Some(6.0));
4808        assert_eq!(node.max_numeric_value(), Some(72.0));
4809        assert_eq!(node.numeric_value_step(), Some(1.0));
4810    }
4811
4812    /// Two focusable, clickable elements ("a" and "b") used to exercise the
4813    /// Enter/Space -> synthesized click press/release pairing.
4814    struct KeyboardActivationTest {
4815        focus_a: FocusHandle,
4816        focus_b: FocusHandle,
4817        clicks: Rc<RefCell<Vec<&'static str>>>,
4818    }
4819
4820    impl Render for KeyboardActivationTest {
4821        fn render(&mut self, _window: &mut Window, _cx: &mut Context<Self>) -> impl IntoElement {
4822            let clicks_a = self.clicks.clone();
4823            let clicks_b = self.clicks.clone();
4824            div()
4825                .size_full()
4826                .child(
4827                    div()
4828                        .id("a")
4829                        .w(px(50.))
4830                        .h(px(50.))
4831                        .track_focus(&self.focus_a)
4832                        .on_click(move |_, _, _| clicks_a.borrow_mut().push("a")),
4833                )
4834                .child(
4835                    div()
4836                        .id("b")
4837                        .w(px(50.))
4838                        .h(px(50.))
4839                        .track_focus(&self.focus_b)
4840                        .on_click(move |_, _, _| clicks_b.borrow_mut().push("b")),
4841                )
4842        }
4843    }
4844
4845    fn setup_keyboard_activation_test() -> (
4846        TestAppContext,
4847        AnyWindowHandle,
4848        Rc<RefCell<Vec<&'static str>>>,
4849        FocusHandle,
4850        FocusHandle,
4851    ) {
4852        let mut cx = TestAppContext::single();
4853        let (focus_a, focus_b) = cx.update(|cx| (cx.focus_handle(), cx.focus_handle()));
4854        let clicks: Rc<RefCell<Vec<&'static str>>> = Rc::new(RefCell::new(Vec::new()));
4855        let window = cx.add_window({
4856            let focus_a = focus_a.clone();
4857            let focus_b = focus_b.clone();
4858            let clicks = clicks.clone();
4859            move |_, _| KeyboardActivationTest {
4860                focus_a,
4861                focus_b,
4862                clicks,
4863            }
4864        });
4865        (cx, window.into(), clicks, focus_a, focus_b)
4866    }
4867
4868    /// Move focus to `handle`, flush effects, then paint so the newly focused
4869    /// element registers its key handlers for the next dispatched event.
4870    fn focus_and_draw(cx: &mut TestAppContext, window: AnyWindowHandle, handle: &FocusHandle) {
4871        cx.update_window(window, |_, window, cx| window.focus(handle, cx))
4872            .unwrap();
4873        cx.run_until_parked();
4874        cx.update_window(window, |_, window, cx| {
4875            window.draw(cx).clear(cx);
4876        })
4877        .unwrap();
4878    }
4879
4880    fn key_down(cx: &mut TestAppContext, window: AnyWindowHandle, key: &str) {
4881        let keystroke = Keystroke::parse(key).unwrap();
4882        cx.update_window(window, |_, window, cx| {
4883            window.dispatch_event(
4884                KeyDownEvent {
4885                    keystroke,
4886                    is_held: false,
4887                    prefer_character_input: false,
4888                }
4889                .to_platform_input(),
4890                cx,
4891            );
4892        })
4893        .unwrap();
4894    }
4895
4896    fn key_up(cx: &mut TestAppContext, window: AnyWindowHandle, key: &str) {
4897        let keystroke = Keystroke::parse(key).unwrap();
4898        cx.update_window(window, |_, window, cx| {
4899            window.dispatch_event(KeyUpEvent { keystroke }.to_platform_input(), cx);
4900        })
4901        .unwrap();
4902    }
4903
4904    /// Pressing and releasing Enter on the same focused element fires a click.
4905    #[test]
4906    fn keyboard_activation_fires_click_on_same_element() {
4907        let (mut cx, window, clicks, focus_a, _focus_b) = setup_keyboard_activation_test();
4908
4909        focus_and_draw(&mut cx, window, &focus_a);
4910        key_down(&mut cx, window, "enter");
4911        key_up(&mut cx, window, "enter");
4912
4913        assert_eq!(*clicks.borrow(), vec!["a"]);
4914    }
4915
4916    /// A key-down whose key-up lands on a *different* element (because focus
4917    /// moved in between) must not leak a synthesized click onto the newly
4918    /// focused element. This is the core regression: previously the key-up
4919    /// handler fired unconditionally on whatever was focused at key-up time.
4920    #[test]
4921    fn keyboard_activation_does_not_leak_across_focus_change() {
4922        let (mut cx, window, clicks, focus_a, focus_b) = setup_keyboard_activation_test();
4923
4924        // Enter pressed while "a" is focused...
4925        focus_and_draw(&mut cx, window, &focus_a);
4926        key_down(&mut cx, window, "enter");
4927
4928        // ...focus moves to "b" before the release (as a confirm action would)...
4929        focus_and_draw(&mut cx, window, &focus_b);
4930        key_up(&mut cx, window, "enter");
4931
4932        // ...so neither element is clicked: "a" never saw the up, and "b"
4933        // never saw the down.
4934        assert!(clicks.borrow().is_empty(), "clicks: {:?}", clicks.borrow());
4935    }
4936
4937    /// A keydown whose flag is left pending because focus moved away before
4938    /// the keyup must not fire a click when focus later *returns* to the same
4939    /// element (the menu trigger reopening case). The stamped focus generation
4940    /// no longer matches, so the stale pending state is ignored.
4941    #[test]
4942    fn keyboard_activation_does_not_leak_when_focus_returns() {
4943        let (mut cx, window, clicks, focus_a, focus_b) = setup_keyboard_activation_test();
4944
4945        // Enter pressed on "a"...
4946        focus_and_draw(&mut cx, window, &focus_a);
4947        key_down(&mut cx, window, "enter");
4948
4949        // ...focus leaves "a" before its keyup (so the pending state is never
4950        // consumed), then comes back to "a"...
4951        focus_and_draw(&mut cx, window, &focus_b);
4952        focus_and_draw(&mut cx, window, &focus_a);
4953        key_up(&mut cx, window, "enter");
4954
4955        // ...and the now-stale pending keydown must not fire a click.
4956        assert!(clicks.borrow().is_empty(), "clicks: {:?}", clicks.borrow());
4957    }
4958
4959    /// A non-activation key *released* during the press must cancel the pending
4960    /// activation. For the sequence escape-down, space-down, escape-up,
4961    /// space-up the space forms a clean down/up pair, but the intervening
4962    /// escape-up means this isn't a plain space activation, so no click fires.
4963    #[test]
4964    fn keyboard_activation_cleared_by_intervening_key_release() {
4965        let (mut cx, window, clicks, focus_a, _focus_b) = setup_keyboard_activation_test();
4966
4967        focus_and_draw(&mut cx, window, &focus_a);
4968        key_down(&mut cx, window, "escape");
4969        key_down(&mut cx, window, "space");
4970        key_up(&mut cx, window, "escape");
4971        key_up(&mut cx, window, "space");
4972
4973        assert!(clicks.borrow().is_empty(), "clicks: {:?}", clicks.borrow());
4974    }
4975
4976    /// The flag is a single activation marker, not keyed by which activation
4977    /// key was used, so a Space down paired with an Enter up on the same
4978    /// element still fires a click.
4979    #[test]
4980    fn keyboard_activation_does_not_distinguish_space_and_enter() {
4981        let (mut cx, window, clicks, focus_a, _focus_b) = setup_keyboard_activation_test();
4982
4983        focus_and_draw(&mut cx, window, &focus_a);
4984        key_down(&mut cx, window, "space");
4985        key_up(&mut cx, window, "enter");
4986
4987        assert_eq!(*clicks.borrow(), vec!["a"]);
4988    }
4989
4990    /// A non-activation key pressed between the activation down and up clears
4991    /// the pending flag, suppressing the click.
4992    #[test]
4993    fn keyboard_activation_cleared_by_intervening_keydown() {
4994        let (mut cx, window, clicks, focus_a, _focus_b) = setup_keyboard_activation_test();
4995
4996        focus_and_draw(&mut cx, window, &focus_a);
4997        key_down(&mut cx, window, "enter");
4998        key_down(&mut cx, window, "a");
4999        key_up(&mut cx, window, "enter");
5000
5001        assert!(clicks.borrow().is_empty(), "clicks: {:?}", clicks.borrow());
5002    }
5003
5004    /// A modified Enter (e.g. cmd-enter) is not treated as an activation key,
5005    /// so it neither sets the pending flag nor fires a click on release.
5006    #[test]
5007    fn keyboard_activation_ignores_modified_keys() {
5008        let (mut cx, window, clicks, focus_a, _focus_b) = setup_keyboard_activation_test();
5009
5010        focus_and_draw(&mut cx, window, &focus_a);
5011        key_down(&mut cx, window, "cmd-enter");
5012        key_up(&mut cx, window, "cmd-enter");
5013
5014        assert!(clicks.borrow().is_empty(), "clicks: {:?}", clicks.borrow());
5015    }
5016
5017    /// Two sibling tab groups, each a focusable container that is *not* itself a
5018    /// tab stop and holds a single tab stop. Mirrors how the title bar and
5019    /// status bar expose their controls as ARIA toolbars.
5020    struct TabGroupFocus {
5021        group_a: FocusHandle,
5022        item_a: FocusHandle,
5023        group_b: FocusHandle,
5024        item_b: FocusHandle,
5025    }
5026
5027    impl Render for TabGroupFocus {
5028        fn render(&mut self, _: &mut Window, _: &mut Context<Self>) -> impl IntoElement {
5029            fn group(container: &FocusHandle, item: &FocusHandle) -> Div {
5030                div()
5031                    .track_focus(container)
5032                    .tab_group()
5033                    .child(div().track_focus(item))
5034            }
5035            div()
5036                .child(group(&self.group_a, &self.item_a))
5037                .child(group(&self.group_b, &self.item_b))
5038        }
5039    }
5040
5041    /// Focusing a tab-group container and pressing Tab (`focus_next`) must move
5042    /// focus to the first tab stop *inside that container*, as documented on
5043    /// [`InteractiveElement::tab_stop`].
5044    #[test]
5045    fn focus_next_from_tab_group_container_enters_that_group() {
5046        let mut cx = TestAppContext::single();
5047        let (group_a, item_a, group_b, item_b) = cx.update(|cx| {
5048            (
5049                cx.focus_handle(),
5050                cx.focus_handle().tab_stop(true),
5051                cx.focus_handle(),
5052                cx.focus_handle().tab_stop(true),
5053            )
5054        });
5055        let window: AnyWindowHandle = cx
5056            .add_window({
5057                let (group_a, item_a, group_b, item_b) =
5058                    (group_a, item_a, group_b.clone(), item_b.clone());
5059                move |_, _| TabGroupFocus {
5060                    group_a,
5061                    item_a,
5062                    group_b,
5063                    item_b,
5064                }
5065            })
5066            .into();
5067        cx.update_window(window, |_, window, cx| window.draw(cx).clear(cx))
5068            .unwrap();
5069
5070        // Focus the *second* group's container, then advance like Tab would.
5071        let focused = cx
5072            .update_window(window, |_, window, cx| {
5073                window.focus(&group_b, cx);
5074                window.focus_next(cx);
5075                window.focused(cx).map(|handle| handle.id)
5076            })
5077            .unwrap();
5078
5079        assert_eq!(focused, Some(item_b.id));
5080    }
5081}