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 point, px, size, Action, AnyDrag, AnyElement, AnyTooltip, AnyView, AppContext, Bounds,
20 ClickEvent, DispatchPhase, Element, ElementId, FocusHandle, Global, GlobalElementId, Hitbox,
21 HitboxId, IntoElement, IsZero, KeyContext, KeyDownEvent, KeyUpEvent, LayoutId,
22 ModifiersChangedEvent, MouseButton, MouseDownEvent, MouseMoveEvent, MouseUpEvent,
23 ParentElement, Pixels, Point, Render, ScrollWheelEvent, SharedString, Size, Style,
24 StyleRefinement, Styled, Task, TooltipId, View, Visibility, WindowContext,
25};
26use collections::HashMap;
27use refineable::Refineable;
28use smallvec::SmallVec;
29use std::{
30 any::{Any, TypeId},
31 cell::RefCell,
32 cmp::Ordering,
33 fmt::Debug,
34 marker::PhantomData,
35 mem,
36 ops::DerefMut,
37 rc::Rc,
38 time::Duration,
39};
40use taffy::style::Overflow;
41use util::ResultExt;
42
43const DRAG_THRESHOLD: f64 = 2.;
44pub(crate) const TOOLTIP_DELAY: Duration = Duration::from_millis(500);
45
46/// The styling information for a given group.
47pub struct GroupStyle {
48 /// The identifier for this group.
49 pub group: SharedString,
50
51 /// The specific style refinement that this group would apply
52 /// to its children.
53 pub style: Box<StyleRefinement>,
54}
55
56/// An event for when a drag is moving over this element, with the given state type.
57pub struct DragMoveEvent<T> {
58 /// The mouse move event that triggered this drag move event.
59 pub event: MouseMoveEvent,
60
61 /// The bounds of this element.
62 pub bounds: Bounds<Pixels>,
63 drag: PhantomData<T>,
64}
65
66impl<T: 'static> DragMoveEvent<T> {
67 /// Returns the drag state for this event.
68 pub fn drag<'b>(&self, cx: &'b AppContext) -> &'b T {
69 cx.active_drag
70 .as_ref()
71 .and_then(|drag| drag.value.downcast_ref::<T>())
72 .expect("DragMoveEvent is only valid when the stored active drag is of the same type.")
73 }
74}
75
76impl Interactivity {
77 /// Bind the given callback to the mouse down event for the given mouse button, during the bubble phase
78 /// The imperative API equivalent of [`InteractiveElement::on_mouse_down`]
79 ///
80 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to the view state from this callback.
81 pub fn on_mouse_down(
82 &mut self,
83 button: MouseButton,
84 listener: impl Fn(&MouseDownEvent, &mut WindowContext) + 'static,
85 ) {
86 self.mouse_down_listeners
87 .push(Box::new(move |event, phase, hitbox, cx| {
88 if phase == DispatchPhase::Bubble && event.button == button && hitbox.is_hovered(cx)
89 {
90 (listener)(event, cx)
91 }
92 }));
93 }
94
95 /// Bind the given callback to the mouse down event for any button, during the capture phase
96 /// The imperative API equivalent of [`InteractiveElement::capture_any_mouse_down`]
97 ///
98 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
99 pub fn capture_any_mouse_down(
100 &mut self,
101 listener: impl Fn(&MouseDownEvent, &mut WindowContext) + 'static,
102 ) {
103 self.mouse_down_listeners
104 .push(Box::new(move |event, phase, hitbox, cx| {
105 if phase == DispatchPhase::Capture && hitbox.is_hovered(cx) {
106 (listener)(event, cx)
107 }
108 }));
109 }
110
111 /// Bind the given callback to the mouse down event for any button, during the bubble phase
112 /// the imperative API equivalent to [`InteractiveElement::on_any_mouse_down`]
113 ///
114 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
115 pub fn on_any_mouse_down(
116 &mut self,
117 listener: impl Fn(&MouseDownEvent, &mut WindowContext) + 'static,
118 ) {
119 self.mouse_down_listeners
120 .push(Box::new(move |event, phase, hitbox, cx| {
121 if phase == DispatchPhase::Bubble && hitbox.is_hovered(cx) {
122 (listener)(event, cx)
123 }
124 }));
125 }
126
127 /// Bind the given callback to the mouse up event for the given button, during the bubble phase
128 /// the imperative API equivalent to [`InteractiveElement::on_mouse_up`]
129 ///
130 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
131 pub fn on_mouse_up(
132 &mut self,
133 button: MouseButton,
134 listener: impl Fn(&MouseUpEvent, &mut WindowContext) + 'static,
135 ) {
136 self.mouse_up_listeners
137 .push(Box::new(move |event, phase, hitbox, cx| {
138 if phase == DispatchPhase::Bubble && event.button == button && hitbox.is_hovered(cx)
139 {
140 (listener)(event, cx)
141 }
142 }));
143 }
144
145 /// Bind the given callback to the mouse up event for any button, during the capture phase
146 /// the imperative API equivalent to [`InteractiveElement::capture_any_mouse_up`]
147 ///
148 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
149 pub fn capture_any_mouse_up(
150 &mut self,
151 listener: impl Fn(&MouseUpEvent, &mut WindowContext) + 'static,
152 ) {
153 self.mouse_up_listeners
154 .push(Box::new(move |event, phase, hitbox, cx| {
155 if phase == DispatchPhase::Capture && hitbox.is_hovered(cx) {
156 (listener)(event, cx)
157 }
158 }));
159 }
160
161 /// Bind the given callback to the mouse up event for any button, during the bubble phase
162 /// the imperative API equivalent to [`Interactivity::on_any_mouse_up`]
163 ///
164 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
165 pub fn on_any_mouse_up(
166 &mut self,
167 listener: impl Fn(&MouseUpEvent, &mut WindowContext) + 'static,
168 ) {
169 self.mouse_up_listeners
170 .push(Box::new(move |event, phase, hitbox, cx| {
171 if phase == DispatchPhase::Bubble && hitbox.is_hovered(cx) {
172 (listener)(event, cx)
173 }
174 }));
175 }
176
177 /// Bind the given callback to the mouse down event, on any button, during the capture phase,
178 /// when the mouse is outside of the bounds of this element.
179 /// The imperative API equivalent to [`InteractiveElement::on_mouse_down_out`]
180 ///
181 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
182 pub fn on_mouse_down_out(
183 &mut self,
184 listener: impl Fn(&MouseDownEvent, &mut WindowContext) + 'static,
185 ) {
186 self.mouse_down_listeners
187 .push(Box::new(move |event, phase, hitbox, cx| {
188 if phase == DispatchPhase::Capture && !hitbox.contains(&cx.mouse_position()) {
189 (listener)(event, cx)
190 }
191 }));
192 }
193
194 /// Bind the given callback to the mouse up event, for the given button, during the capture phase,
195 /// when the mouse is outside of the bounds of this element.
196 /// The imperative API equivalent to [`InteractiveElement::on_mouse_up_out`]
197 ///
198 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
199 pub fn on_mouse_up_out(
200 &mut self,
201 button: MouseButton,
202 listener: impl Fn(&MouseUpEvent, &mut WindowContext) + 'static,
203 ) {
204 self.mouse_up_listeners
205 .push(Box::new(move |event, phase, hitbox, cx| {
206 if phase == DispatchPhase::Capture
207 && event.button == button
208 && !hitbox.is_hovered(cx)
209 {
210 (listener)(event, cx);
211 }
212 }));
213 }
214
215 /// Bind the given callback to the mouse move event, during the bubble phase
216 /// The imperative API equivalent to [`InteractiveElement::on_mouse_move`]
217 ///
218 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
219 pub fn on_mouse_move(
220 &mut self,
221 listener: impl Fn(&MouseMoveEvent, &mut WindowContext) + 'static,
222 ) {
223 self.mouse_move_listeners
224 .push(Box::new(move |event, phase, hitbox, cx| {
225 if phase == DispatchPhase::Bubble && hitbox.is_hovered(cx) {
226 (listener)(event, cx);
227 }
228 }));
229 }
230
231 /// Bind the given callback to the mouse drag event of the given type. Note that this
232 /// will be called for all move events, inside or outside of this element, as long as the
233 /// drag was started with this element under the mouse. Useful for implementing draggable
234 /// UIs that don't conform to a drag and drop style interaction, like resizing.
235 /// The imperative API equivalent to [`InteractiveElement::on_drag_move`]
236 ///
237 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
238 pub fn on_drag_move<T>(
239 &mut self,
240 listener: impl Fn(&DragMoveEvent<T>, &mut WindowContext) + 'static,
241 ) where
242 T: 'static,
243 {
244 self.mouse_move_listeners
245 .push(Box::new(move |event, phase, hitbox, cx| {
246 if phase == DispatchPhase::Capture
247 && cx
248 .active_drag
249 .as_ref()
250 .is_some_and(|drag| drag.value.as_ref().type_id() == TypeId::of::<T>())
251 {
252 (listener)(
253 &DragMoveEvent {
254 event: event.clone(),
255 bounds: hitbox.bounds,
256 drag: PhantomData,
257 },
258 cx,
259 );
260 }
261 }));
262 }
263
264 /// Bind the given callback to scroll wheel events during the bubble phase
265 /// The imperative API equivalent to [`InteractiveElement::on_scroll_wheel`]
266 ///
267 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
268 pub fn on_scroll_wheel(
269 &mut self,
270 listener: impl Fn(&ScrollWheelEvent, &mut WindowContext) + 'static,
271 ) {
272 self.scroll_wheel_listeners
273 .push(Box::new(move |event, phase, hitbox, cx| {
274 if phase == DispatchPhase::Bubble && hitbox.is_hovered(cx) {
275 (listener)(event, cx);
276 }
277 }));
278 }
279
280 /// Bind the given callback to an action dispatch during the capture phase
281 /// The imperative API equivalent to [`InteractiveElement::capture_action`]
282 ///
283 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
284 pub fn capture_action<A: Action>(
285 &mut self,
286 listener: impl Fn(&A, &mut WindowContext) + 'static,
287 ) {
288 self.action_listeners.push((
289 TypeId::of::<A>(),
290 Box::new(move |action, phase, cx| {
291 let action = action.downcast_ref().unwrap();
292 if phase == DispatchPhase::Capture {
293 (listener)(action, cx)
294 } else {
295 cx.propagate();
296 }
297 }),
298 ));
299 }
300
301 /// Bind the given callback to an action dispatch during the bubble phase
302 /// The imperative API equivalent to [`InteractiveElement::on_action`]
303 ///
304 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
305 pub fn on_action<A: Action>(&mut self, listener: impl Fn(&A, &mut WindowContext) + 'static) {
306 self.action_listeners.push((
307 TypeId::of::<A>(),
308 Box::new(move |action, phase, cx| {
309 let action = action.downcast_ref().unwrap();
310 if phase == DispatchPhase::Bubble {
311 (listener)(action, cx)
312 }
313 }),
314 ));
315 }
316
317 /// Bind the given callback to an action dispatch, based on a dynamic action parameter
318 /// instead of a type parameter. Useful for component libraries that want to expose
319 /// action bindings to their users.
320 /// The imperative API equivalent to [`InteractiveElement::on_boxed_action`]
321 ///
322 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
323 pub fn on_boxed_action(
324 &mut self,
325 action: &dyn Action,
326 listener: impl Fn(&dyn Action, &mut WindowContext) + 'static,
327 ) {
328 let action = action.boxed_clone();
329 self.action_listeners.push((
330 (*action).type_id(),
331 Box::new(move |_, phase, cx| {
332 if phase == DispatchPhase::Bubble {
333 (listener)(&*action, cx)
334 }
335 }),
336 ));
337 }
338
339 /// Bind the given callback to key down events during the bubble phase
340 /// The imperative API equivalent to [`InteractiveElement::on_key_down`]
341 ///
342 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
343 pub fn on_key_down(&mut self, listener: impl Fn(&KeyDownEvent, &mut WindowContext) + 'static) {
344 self.key_down_listeners
345 .push(Box::new(move |event, phase, cx| {
346 if phase == DispatchPhase::Bubble {
347 (listener)(event, cx)
348 }
349 }));
350 }
351
352 /// Bind the given callback to key down events during the capture phase
353 /// The imperative API equivalent to [`InteractiveElement::capture_key_down`]
354 ///
355 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
356 pub fn capture_key_down(
357 &mut self,
358 listener: impl Fn(&KeyDownEvent, &mut WindowContext) + 'static,
359 ) {
360 self.key_down_listeners
361 .push(Box::new(move |event, phase, cx| {
362 if phase == DispatchPhase::Capture {
363 listener(event, cx)
364 }
365 }));
366 }
367
368 /// Bind the given callback to key up events during the bubble phase
369 /// The imperative API equivalent to [`InteractiveElement::on_key_up`]
370 ///
371 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
372 pub fn on_key_up(&mut self, listener: impl Fn(&KeyUpEvent, &mut WindowContext) + 'static) {
373 self.key_up_listeners
374 .push(Box::new(move |event, phase, cx| {
375 if phase == DispatchPhase::Bubble {
376 listener(event, cx)
377 }
378 }));
379 }
380
381 /// Bind the given callback to key up events during the capture phase
382 /// The imperative API equivalent to [`InteractiveElement::on_key_up`]
383 ///
384 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
385 pub fn capture_key_up(&mut self, listener: impl Fn(&KeyUpEvent, &mut WindowContext) + 'static) {
386 self.key_up_listeners
387 .push(Box::new(move |event, phase, cx| {
388 if phase == DispatchPhase::Capture {
389 listener(event, cx)
390 }
391 }));
392 }
393
394 /// Bind the given callback to modifiers changing events.
395 /// The imperative API equivalent to [`InteractiveElement::on_modifiers_changed`]
396 ///
397 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
398 pub fn on_modifiers_changed(
399 &mut self,
400 listener: impl Fn(&ModifiersChangedEvent, &mut WindowContext) + 'static,
401 ) {
402 self.modifiers_changed_listeners
403 .push(Box::new(move |event, cx| listener(event, cx)));
404 }
405
406 /// Bind the given callback to drop events of the given type, whether or not the drag started on this element
407 /// The imperative API equivalent to [`InteractiveElement::on_drop`]
408 ///
409 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
410 pub fn on_drop<T: 'static>(&mut self, listener: impl Fn(&T, &mut WindowContext) + 'static) {
411 self.drop_listeners.push((
412 TypeId::of::<T>(),
413 Box::new(move |dragged_value, cx| {
414 listener(dragged_value.downcast_ref().unwrap(), cx);
415 }),
416 ));
417 }
418
419 /// Use the given predicate to determine whether or not a drop event should be dispatched to this element
420 /// The imperative API equivalent to [`InteractiveElement::can_drop`]
421 pub fn can_drop(&mut self, predicate: impl Fn(&dyn Any, &mut WindowContext) -> bool + 'static) {
422 self.can_drop_predicate = Some(Box::new(predicate));
423 }
424
425 /// Bind the given callback to click events of this element
426 /// The imperative API equivalent to [`StatefulInteractiveElement::on_click`]
427 ///
428 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
429 pub fn on_click(&mut self, listener: impl Fn(&ClickEvent, &mut WindowContext) + 'static)
430 where
431 Self: Sized,
432 {
433 self.click_listeners
434 .push(Box::new(move |event, cx| listener(event, cx)));
435 }
436
437 /// On drag initiation, this callback will be used to create a new view to render the dragged value for a
438 /// drag and drop operation. This API should also be used as the equivalent of 'on drag start' with
439 /// the [`Self::on_drag_move`] API
440 /// The imperative API equivalent to [`StatefulInteractiveElement::on_drag`]
441 ///
442 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
443 pub fn on_drag<T, W>(
444 &mut self,
445 value: T,
446 constructor: impl Fn(&T, &mut WindowContext) -> View<W> + 'static,
447 ) where
448 Self: Sized,
449 T: 'static,
450 W: 'static + Render,
451 {
452 debug_assert!(
453 self.drag_listener.is_none(),
454 "calling on_drag more than once on the same element is not supported"
455 );
456 self.drag_listener = Some((
457 Box::new(value),
458 Box::new(move |value, cx| constructor(value.downcast_ref().unwrap(), cx).into()),
459 ));
460 }
461
462 /// Bind the given callback on the hover start and end events of this element. Note that the boolean
463 /// passed to the callback is true when the hover starts and false when it ends.
464 /// The imperative API equivalent to [`StatefulInteractiveElement::on_drag`]
465 ///
466 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
467 pub fn on_hover(&mut self, listener: impl Fn(&bool, &mut WindowContext) + 'static)
468 where
469 Self: Sized,
470 {
471 debug_assert!(
472 self.hover_listener.is_none(),
473 "calling on_hover more than once on the same element is not supported"
474 );
475 self.hover_listener = Some(Box::new(listener));
476 }
477
478 /// Use the given callback to construct a new tooltip view when the mouse hovers over this element.
479 /// The imperative API equivalent to [`InteractiveElement::tooltip`]
480 pub fn tooltip(&mut self, build_tooltip: impl Fn(&mut WindowContext) -> AnyView + 'static)
481 where
482 Self: Sized,
483 {
484 debug_assert!(
485 self.tooltip_builder.is_none(),
486 "calling tooltip more than once on the same element is not supported"
487 );
488 self.tooltip_builder = Some(TooltipBuilder {
489 build: Rc::new(build_tooltip),
490 hoverable: false,
491 });
492 }
493
494 /// Use the given callback to construct a new tooltip view when the mouse hovers over this element.
495 /// The tooltip itself is also hoverable and won't disappear when the user moves the mouse into
496 /// the tooltip. The imperative API equivalent to [`InteractiveElement::hoverable_tooltip`]
497 pub fn hoverable_tooltip(
498 &mut self,
499 build_tooltip: impl Fn(&mut WindowContext) -> AnyView + 'static,
500 ) where
501 Self: Sized,
502 {
503 debug_assert!(
504 self.tooltip_builder.is_none(),
505 "calling tooltip more than once on the same element is not supported"
506 );
507 self.tooltip_builder = Some(TooltipBuilder {
508 build: Rc::new(build_tooltip),
509 hoverable: true,
510 });
511 }
512
513 /// Block the mouse from interacting with this element or any of its children
514 /// The imperative API equivalent to [`InteractiveElement::block_mouse`]
515 pub fn occlude_mouse(&mut self) {
516 self.occlude_mouse = true;
517 }
518}
519
520/// A trait for elements that want to use the standard GPUI event handlers that don't
521/// require any state.
522pub trait InteractiveElement: Sized {
523 /// Retrieve the interactivity state associated with this element
524 fn interactivity(&mut self) -> &mut Interactivity;
525
526 /// Assign this element to a group of elements that can be styled together
527 fn group(mut self, group: impl Into<SharedString>) -> Self {
528 self.interactivity().group = Some(group.into());
529 self
530 }
531
532 /// Assign this element an ID, so that it can be used with interactivity
533 fn id(mut self, id: impl Into<ElementId>) -> Stateful<Self> {
534 self.interactivity().element_id = Some(id.into());
535
536 Stateful { element: self }
537 }
538
539 /// Track the focus state of the given focus handle on this element.
540 /// If the focus handle is focused by the application, this element will
541 /// apply its focused styles.
542 fn track_focus(mut self, focus_handle: &FocusHandle) -> Focusable<Self> {
543 self.interactivity().focusable = true;
544 self.interactivity().tracked_focus_handle = Some(focus_handle.clone());
545 Focusable { element: self }
546 }
547
548 /// Set the keymap context for this element. This will be used to determine
549 /// which action to dispatch from the keymap.
550 fn key_context<C, E>(mut self, key_context: C) -> Self
551 where
552 C: TryInto<KeyContext, Error = E>,
553 E: Debug,
554 {
555 if let Some(key_context) = key_context.try_into().log_err() {
556 self.interactivity().key_context = Some(key_context);
557 }
558 self
559 }
560
561 /// Apply the given style to this element when the mouse hovers over it
562 fn hover(mut self, f: impl FnOnce(StyleRefinement) -> StyleRefinement) -> Self {
563 debug_assert!(
564 self.interactivity().hover_style.is_none(),
565 "hover style already set"
566 );
567 self.interactivity().hover_style = Some(Box::new(f(StyleRefinement::default())));
568 self
569 }
570
571 /// Apply the given style to this element when the mouse hovers over a group member
572 fn group_hover(
573 mut self,
574 group_name: impl Into<SharedString>,
575 f: impl FnOnce(StyleRefinement) -> StyleRefinement,
576 ) -> Self {
577 self.interactivity().group_hover_style = Some(GroupStyle {
578 group: group_name.into(),
579 style: Box::new(f(StyleRefinement::default())),
580 });
581 self
582 }
583
584 /// Bind the given callback to the mouse down event for the given mouse button,
585 /// the fluent API equivalent to [`Interactivity::on_mouse_down`]
586 ///
587 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to the view state from this callback.
588 fn on_mouse_down(
589 mut self,
590 button: MouseButton,
591 listener: impl Fn(&MouseDownEvent, &mut WindowContext) + 'static,
592 ) -> Self {
593 self.interactivity().on_mouse_down(button, listener);
594 self
595 }
596
597 #[cfg(any(test, feature = "test-support"))]
598 /// Set a key that can be used to look up this element's bounds
599 /// in the [`VisualTestContext::debug_bounds`] map
600 /// This is a noop in release builds
601 fn debug_selector(mut self, f: impl FnOnce() -> String) -> Self {
602 self.interactivity().debug_selector = Some(f());
603 self
604 }
605
606 #[cfg(not(any(test, feature = "test-support")))]
607 /// Set a key that can be used to look up this element's bounds
608 /// in the [`VisualTestContext::debug_bounds`] map
609 /// This is a noop in release builds
610 #[inline]
611 fn debug_selector(self, _: impl FnOnce() -> String) -> Self {
612 self
613 }
614
615 /// Bind the given callback to the mouse down event for any button, during the capture phase
616 /// the fluent API equivalent to [`Interactivity::capture_any_mouse_down`]
617 ///
618 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
619 fn capture_any_mouse_down(
620 mut self,
621 listener: impl Fn(&MouseDownEvent, &mut WindowContext) + 'static,
622 ) -> Self {
623 self.interactivity().capture_any_mouse_down(listener);
624 self
625 }
626
627 /// Bind the given callback to the mouse down event for any button, during the capture phase
628 /// the fluent API equivalent to [`Interactivity::on_any_mouse_down`]
629 ///
630 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
631 fn on_any_mouse_down(
632 mut self,
633 listener: impl Fn(&MouseDownEvent, &mut WindowContext) + 'static,
634 ) -> Self {
635 self.interactivity().on_any_mouse_down(listener);
636 self
637 }
638
639 /// Bind the given callback to the mouse up event for the given button, during the bubble phase
640 /// the fluent API equivalent to [`Interactivity::on_mouse_up`]
641 ///
642 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
643 fn on_mouse_up(
644 mut self,
645 button: MouseButton,
646 listener: impl Fn(&MouseUpEvent, &mut WindowContext) + 'static,
647 ) -> Self {
648 self.interactivity().on_mouse_up(button, listener);
649 self
650 }
651
652 /// Bind the given callback to the mouse up event for any button, during the capture phase
653 /// the fluent API equivalent to [`Interactivity::capture_any_mouse_up`]
654 ///
655 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
656 fn capture_any_mouse_up(
657 mut self,
658 listener: impl Fn(&MouseUpEvent, &mut WindowContext) + 'static,
659 ) -> Self {
660 self.interactivity().capture_any_mouse_up(listener);
661 self
662 }
663
664 /// Bind the given callback to the mouse down event, on any button, during the capture phase,
665 /// when the mouse is outside of the bounds of this element.
666 /// The fluent API equivalent to [`Interactivity::on_mouse_down_out`]
667 ///
668 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
669 fn on_mouse_down_out(
670 mut self,
671 listener: impl Fn(&MouseDownEvent, &mut WindowContext) + 'static,
672 ) -> Self {
673 self.interactivity().on_mouse_down_out(listener);
674 self
675 }
676
677 /// Bind the given callback to the mouse up event, for the given button, during the capture phase,
678 /// when the mouse is outside of the bounds of this element.
679 /// The fluent API equivalent to [`Interactivity::on_mouse_up_out`]
680 ///
681 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
682 fn on_mouse_up_out(
683 mut self,
684 button: MouseButton,
685 listener: impl Fn(&MouseUpEvent, &mut WindowContext) + 'static,
686 ) -> Self {
687 self.interactivity().on_mouse_up_out(button, listener);
688 self
689 }
690
691 /// Bind the given callback to the mouse move event, during the bubble phase
692 /// The fluent API equivalent to [`Interactivity::on_mouse_move`]
693 ///
694 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
695 fn on_mouse_move(
696 mut self,
697 listener: impl Fn(&MouseMoveEvent, &mut WindowContext) + 'static,
698 ) -> Self {
699 self.interactivity().on_mouse_move(listener);
700 self
701 }
702
703 /// Bind the given callback to the mouse drag event of the given type. Note that this
704 /// will be called for all move events, inside or outside of this element, as long as the
705 /// drag was started with this element under the mouse. Useful for implementing draggable
706 /// UIs that don't conform to a drag and drop style interaction, like resizing.
707 /// The fluent API equivalent to [`Interactivity::on_drag_move`]
708 ///
709 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
710 fn on_drag_move<T: 'static>(
711 mut self,
712 listener: impl Fn(&DragMoveEvent<T>, &mut WindowContext) + 'static,
713 ) -> Self {
714 self.interactivity().on_drag_move(listener);
715 self
716 }
717
718 /// Bind the given callback to scroll wheel events during the bubble phase
719 /// The fluent API equivalent to [`Interactivity::on_scroll_wheel`]
720 ///
721 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
722 fn on_scroll_wheel(
723 mut self,
724 listener: impl Fn(&ScrollWheelEvent, &mut WindowContext) + 'static,
725 ) -> Self {
726 self.interactivity().on_scroll_wheel(listener);
727 self
728 }
729
730 /// Capture the given action, before normal action dispatch can fire
731 /// The fluent API equivalent to [`Interactivity::on_scroll_wheel`]
732 ///
733 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
734 fn capture_action<A: Action>(
735 mut self,
736 listener: impl Fn(&A, &mut WindowContext) + 'static,
737 ) -> Self {
738 self.interactivity().capture_action(listener);
739 self
740 }
741
742 /// Bind the given callback to an action dispatch during the bubble phase
743 /// The fluent API equivalent to [`Interactivity::on_action`]
744 ///
745 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
746 fn on_action<A: Action>(mut self, listener: impl Fn(&A, &mut WindowContext) + 'static) -> Self {
747 self.interactivity().on_action(listener);
748 self
749 }
750
751 /// Bind the given callback to an action dispatch, based on a dynamic action parameter
752 /// instead of a type parameter. Useful for component libraries that want to expose
753 /// action bindings to their users.
754 /// The fluent API equivalent to [`Interactivity::on_boxed_action`]
755 ///
756 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
757 fn on_boxed_action(
758 mut self,
759 action: &dyn Action,
760 listener: impl Fn(&dyn Action, &mut WindowContext) + 'static,
761 ) -> Self {
762 self.interactivity().on_boxed_action(action, listener);
763 self
764 }
765
766 /// Bind the given callback to key down events during the bubble phase
767 /// The fluent API equivalent to [`Interactivity::on_key_down`]
768 ///
769 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
770 fn on_key_down(
771 mut self,
772 listener: impl Fn(&KeyDownEvent, &mut WindowContext) + 'static,
773 ) -> Self {
774 self.interactivity().on_key_down(listener);
775 self
776 }
777
778 /// Bind the given callback to key down events during the capture phase
779 /// The fluent API equivalent to [`Interactivity::capture_key_down`]
780 ///
781 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
782 fn capture_key_down(
783 mut self,
784 listener: impl Fn(&KeyDownEvent, &mut WindowContext) + 'static,
785 ) -> Self {
786 self.interactivity().capture_key_down(listener);
787 self
788 }
789
790 /// Bind the given callback to key up events during the bubble phase
791 /// The fluent API equivalent to [`Interactivity::on_key_up`]
792 ///
793 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
794 fn on_key_up(mut self, listener: impl Fn(&KeyUpEvent, &mut WindowContext) + 'static) -> Self {
795 self.interactivity().on_key_up(listener);
796 self
797 }
798
799 /// Bind the given callback to key up events during the capture phase
800 /// The fluent API equivalent to [`Interactivity::capture_key_up`]
801 ///
802 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
803 fn capture_key_up(
804 mut self,
805 listener: impl Fn(&KeyUpEvent, &mut WindowContext) + 'static,
806 ) -> Self {
807 self.interactivity().capture_key_up(listener);
808 self
809 }
810
811 /// Bind the given callback to modifiers changing events.
812 /// The fluent API equivalent to [`Interactivity::on_modifiers_changed`]
813 ///
814 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
815 fn on_modifiers_changed(
816 mut self,
817 listener: impl Fn(&ModifiersChangedEvent, &mut WindowContext) + 'static,
818 ) -> Self {
819 self.interactivity().on_modifiers_changed(listener);
820 self
821 }
822
823 /// Apply the given style when the given data type is dragged over this element
824 fn drag_over<S: 'static>(
825 mut self,
826 f: impl 'static + Fn(StyleRefinement, &S, &WindowContext) -> StyleRefinement,
827 ) -> Self {
828 self.interactivity().drag_over_styles.push((
829 TypeId::of::<S>(),
830 Box::new(move |currently_dragged: &dyn Any, cx| {
831 f(
832 StyleRefinement::default(),
833 currently_dragged.downcast_ref::<S>().unwrap(),
834 cx,
835 )
836 }),
837 ));
838 self
839 }
840
841 /// Apply the given style when the given data type is dragged over this element's group
842 fn group_drag_over<S: 'static>(
843 mut self,
844 group_name: impl Into<SharedString>,
845 f: impl FnOnce(StyleRefinement) -> StyleRefinement,
846 ) -> Self {
847 self.interactivity().group_drag_over_styles.push((
848 TypeId::of::<S>(),
849 GroupStyle {
850 group: group_name.into(),
851 style: Box::new(f(StyleRefinement::default())),
852 },
853 ));
854 self
855 }
856
857 /// Bind the given callback to drop events of the given type, whether or not the drag started on this element
858 /// The fluent API equivalent to [`Interactivity::on_drop`]
859 ///
860 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
861 fn on_drop<T: 'static>(mut self, listener: impl Fn(&T, &mut WindowContext) + 'static) -> Self {
862 self.interactivity().on_drop(listener);
863 self
864 }
865
866 /// Use the given predicate to determine whether or not a drop event should be dispatched to this element
867 /// The fluent API equivalent to [`Interactivity::can_drop`]
868 fn can_drop(
869 mut self,
870 predicate: impl Fn(&dyn Any, &mut WindowContext) -> bool + 'static,
871 ) -> Self {
872 self.interactivity().can_drop(predicate);
873 self
874 }
875
876 /// Block the mouse from interacting with this element or any of its children
877 /// The fluent API equivalent to [`Interactivity::block_mouse`]
878 fn occlude(mut self) -> Self {
879 self.interactivity().occlude_mouse();
880 self
881 }
882}
883
884/// A trait for elements that want to use the standard GPUI interactivity features
885/// that require state.
886pub trait StatefulInteractiveElement: InteractiveElement {
887 /// Set this element to focusable.
888 fn focusable(mut self) -> Focusable<Self> {
889 self.interactivity().focusable = true;
890 Focusable { element: self }
891 }
892
893 /// Set the overflow x and y to scroll.
894 fn overflow_scroll(mut self) -> Self {
895 self.interactivity().base_style.overflow.x = Some(Overflow::Scroll);
896 self.interactivity().base_style.overflow.y = Some(Overflow::Scroll);
897 self
898 }
899
900 /// Set the overflow x to scroll.
901 fn overflow_x_scroll(mut self) -> Self {
902 self.interactivity().base_style.overflow.x = Some(Overflow::Scroll);
903 self
904 }
905
906 /// Set the overflow y to scroll.
907 fn overflow_y_scroll(mut self) -> Self {
908 self.interactivity().base_style.overflow.y = Some(Overflow::Scroll);
909 self
910 }
911
912 /// Track the scroll state of this element with the given handle.
913 fn track_scroll(mut self, scroll_handle: &ScrollHandle) -> Self {
914 self.interactivity().tracked_scroll_handle = Some(scroll_handle.clone());
915 self
916 }
917
918 /// Track the scroll state of this element with the given handle.
919 fn anchor_scroll(mut self, scroll_anchor: Option<ScrollAnchor>) -> Self {
920 self.interactivity().scroll_anchor = scroll_anchor;
921 self
922 }
923
924 /// Set the given styles to be applied when this element is active.
925 fn active(mut self, f: impl FnOnce(StyleRefinement) -> StyleRefinement) -> Self
926 where
927 Self: Sized,
928 {
929 self.interactivity().active_style = Some(Box::new(f(StyleRefinement::default())));
930 self
931 }
932
933 /// Set the given styles to be applied when this element's group is active.
934 fn group_active(
935 mut self,
936 group_name: impl Into<SharedString>,
937 f: impl FnOnce(StyleRefinement) -> StyleRefinement,
938 ) -> Self
939 where
940 Self: Sized,
941 {
942 self.interactivity().group_active_style = Some(GroupStyle {
943 group: group_name.into(),
944 style: Box::new(f(StyleRefinement::default())),
945 });
946 self
947 }
948
949 /// Bind the given callback to click events of this element
950 /// The fluent API equivalent to [`Interactivity::on_click`]
951 ///
952 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
953 fn on_click(mut self, listener: impl Fn(&ClickEvent, &mut WindowContext) + 'static) -> Self
954 where
955 Self: Sized,
956 {
957 self.interactivity().on_click(listener);
958 self
959 }
960
961 /// On drag initiation, this callback will be used to create a new view to render the dragged value for a
962 /// drag and drop operation. This API should also be used as the equivalent of 'on drag start' with
963 /// the [`Self::on_drag_move`] API
964 /// The fluent API equivalent to [`Interactivity::on_drag`]
965 ///
966 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
967 fn on_drag<T, W>(
968 mut self,
969 value: T,
970 constructor: impl Fn(&T, &mut WindowContext) -> View<W> + 'static,
971 ) -> Self
972 where
973 Self: Sized,
974 T: 'static,
975 W: 'static + Render,
976 {
977 self.interactivity().on_drag(value, constructor);
978 self
979 }
980
981 /// Bind the given callback on the hover start and end events of this element. Note that the boolean
982 /// passed to the callback is true when the hover starts and false when it ends.
983 /// The fluent API equivalent to [`Interactivity::on_hover`]
984 ///
985 /// See [`ViewContext::listener`](crate::ViewContext::listener) to get access to a view's state from this callback.
986 fn on_hover(mut self, listener: impl Fn(&bool, &mut WindowContext) + 'static) -> Self
987 where
988 Self: Sized,
989 {
990 self.interactivity().on_hover(listener);
991 self
992 }
993
994 /// Use the given callback to construct a new tooltip view when the mouse hovers over this element.
995 /// The fluent API equivalent to [`Interactivity::tooltip`]
996 fn tooltip(mut self, build_tooltip: impl Fn(&mut WindowContext) -> AnyView + 'static) -> Self
997 where
998 Self: Sized,
999 {
1000 self.interactivity().tooltip(build_tooltip);
1001 self
1002 }
1003
1004 /// Use the given callback to construct a new tooltip view when the mouse hovers over this element.
1005 /// The tooltip itself is also hoverable and won't disappear when the user moves the mouse into
1006 /// the tooltip. The fluent API equivalent to [`Interactivity::hoverable_tooltip`]
1007 fn hoverable_tooltip(
1008 mut self,
1009 build_tooltip: impl Fn(&mut WindowContext) -> AnyView + 'static,
1010 ) -> Self
1011 where
1012 Self: Sized,
1013 {
1014 self.interactivity().hoverable_tooltip(build_tooltip);
1015 self
1016 }
1017}
1018
1019/// A trait for providing focus related APIs to interactive elements
1020pub trait FocusableElement: InteractiveElement {
1021 /// Set the given styles to be applied when this element, specifically, is focused.
1022 fn focus(mut self, f: impl FnOnce(StyleRefinement) -> StyleRefinement) -> Self
1023 where
1024 Self: Sized,
1025 {
1026 self.interactivity().focus_style = Some(Box::new(f(StyleRefinement::default())));
1027 self
1028 }
1029
1030 /// Set the given styles to be applied when this element is inside another element that is focused.
1031 fn in_focus(mut self, f: impl FnOnce(StyleRefinement) -> StyleRefinement) -> Self
1032 where
1033 Self: Sized,
1034 {
1035 self.interactivity().in_focus_style = Some(Box::new(f(StyleRefinement::default())));
1036 self
1037 }
1038}
1039
1040pub(crate) type MouseDownListener =
1041 Box<dyn Fn(&MouseDownEvent, DispatchPhase, &Hitbox, &mut WindowContext) + 'static>;
1042pub(crate) type MouseUpListener =
1043 Box<dyn Fn(&MouseUpEvent, DispatchPhase, &Hitbox, &mut WindowContext) + 'static>;
1044
1045pub(crate) type MouseMoveListener =
1046 Box<dyn Fn(&MouseMoveEvent, DispatchPhase, &Hitbox, &mut WindowContext) + 'static>;
1047
1048pub(crate) type ScrollWheelListener =
1049 Box<dyn Fn(&ScrollWheelEvent, DispatchPhase, &Hitbox, &mut WindowContext) + 'static>;
1050
1051pub(crate) type ClickListener = Box<dyn Fn(&ClickEvent, &mut WindowContext) + 'static>;
1052
1053pub(crate) type DragListener = Box<dyn Fn(&dyn Any, &mut WindowContext) -> AnyView + 'static>;
1054
1055type DropListener = Box<dyn Fn(&dyn Any, &mut WindowContext) + 'static>;
1056
1057type CanDropPredicate = Box<dyn Fn(&dyn Any, &mut WindowContext) -> bool + 'static>;
1058
1059pub(crate) struct TooltipBuilder {
1060 build: Rc<dyn Fn(&mut WindowContext) -> AnyView + 'static>,
1061 hoverable: bool,
1062}
1063
1064pub(crate) type KeyDownListener =
1065 Box<dyn Fn(&KeyDownEvent, DispatchPhase, &mut WindowContext) + 'static>;
1066
1067pub(crate) type KeyUpListener =
1068 Box<dyn Fn(&KeyUpEvent, DispatchPhase, &mut WindowContext) + 'static>;
1069
1070pub(crate) type ModifiersChangedListener =
1071 Box<dyn Fn(&ModifiersChangedEvent, &mut WindowContext) + 'static>;
1072
1073pub(crate) type ActionListener = Box<dyn Fn(&dyn Any, DispatchPhase, &mut WindowContext) + 'static>;
1074
1075/// Construct a new [`Div`] element
1076#[track_caller]
1077pub fn div() -> Div {
1078 #[cfg(debug_assertions)]
1079 let interactivity = Interactivity {
1080 location: Some(*core::panic::Location::caller()),
1081 ..Default::default()
1082 };
1083
1084 #[cfg(not(debug_assertions))]
1085 let interactivity = Interactivity::default();
1086
1087 Div {
1088 interactivity,
1089 children: SmallVec::default(),
1090 }
1091}
1092
1093/// A [`Div`] element, the all-in-one element for building complex UIs in GPUI
1094pub struct Div {
1095 interactivity: Interactivity,
1096 children: SmallVec<[AnyElement; 2]>,
1097}
1098
1099/// A frame state for a `Div` element, which contains layout IDs for its children.
1100///
1101/// This struct is used internally by the `Div` element to manage the layout state of its children
1102/// during the UI update cycle. It holds a small vector of `LayoutId` values, each corresponding to
1103/// a child element of the `Div`. These IDs are used to query the layout engine for the computed
1104/// bounds of the children after the layout phase is complete.
1105pub struct DivFrameState {
1106 child_layout_ids: SmallVec<[LayoutId; 2]>,
1107}
1108
1109impl Styled for Div {
1110 fn style(&mut self) -> &mut StyleRefinement {
1111 &mut self.interactivity.base_style
1112 }
1113}
1114
1115impl InteractiveElement for Div {
1116 fn interactivity(&mut self) -> &mut Interactivity {
1117 &mut self.interactivity
1118 }
1119}
1120
1121impl ParentElement for Div {
1122 fn extend(&mut self, elements: impl IntoIterator<Item = AnyElement>) {
1123 self.children.extend(elements)
1124 }
1125}
1126
1127impl Element for Div {
1128 type RequestLayoutState = DivFrameState;
1129 type PrepaintState = Option<Hitbox>;
1130
1131 fn id(&self) -> Option<ElementId> {
1132 self.interactivity.element_id.clone()
1133 }
1134
1135 fn request_layout(
1136 &mut self,
1137 global_id: Option<&GlobalElementId>,
1138 cx: &mut WindowContext,
1139 ) -> (LayoutId, Self::RequestLayoutState) {
1140 let mut child_layout_ids = SmallVec::new();
1141 let layout_id = self
1142 .interactivity
1143 .request_layout(global_id, cx, |style, cx| {
1144 cx.with_text_style(style.text_style().cloned(), |cx| {
1145 child_layout_ids = self
1146 .children
1147 .iter_mut()
1148 .map(|child| child.request_layout(cx))
1149 .collect::<SmallVec<_>>();
1150 cx.request_layout(style, child_layout_ids.iter().copied())
1151 })
1152 });
1153 (layout_id, DivFrameState { child_layout_ids })
1154 }
1155
1156 fn prepaint(
1157 &mut self,
1158 global_id: Option<&GlobalElementId>,
1159 bounds: Bounds<Pixels>,
1160 request_layout: &mut Self::RequestLayoutState,
1161 cx: &mut WindowContext,
1162 ) -> Option<Hitbox> {
1163 let mut child_min = point(Pixels::MAX, Pixels::MAX);
1164 let mut child_max = Point::default();
1165 if let Some(handle) = self.interactivity.scroll_anchor.as_ref() {
1166 *handle.last_origin.borrow_mut() = bounds.origin - cx.element_offset();
1167 }
1168 let content_size = if request_layout.child_layout_ids.is_empty() {
1169 bounds.size
1170 } else if let Some(scroll_handle) = self.interactivity.tracked_scroll_handle.as_ref() {
1171 let mut state = scroll_handle.0.borrow_mut();
1172 state.child_bounds = Vec::with_capacity(request_layout.child_layout_ids.len());
1173 state.bounds = bounds;
1174 let requested = state.requested_scroll_top.take();
1175
1176 for (ix, child_layout_id) in request_layout.child_layout_ids.iter().enumerate() {
1177 let child_bounds = cx.layout_bounds(*child_layout_id);
1178 child_min = child_min.min(&child_bounds.origin);
1179 child_max = child_max.max(&child_bounds.lower_right());
1180 state.child_bounds.push(child_bounds);
1181
1182 if let Some(requested) = requested.as_ref() {
1183 if requested.0 == ix {
1184 *state.offset.borrow_mut() =
1185 bounds.origin - (child_bounds.origin - point(px(0.), requested.1));
1186 }
1187 }
1188 }
1189 (child_max - child_min).into()
1190 } else {
1191 for child_layout_id in &request_layout.child_layout_ids {
1192 let child_bounds = cx.layout_bounds(*child_layout_id);
1193 child_min = child_min.min(&child_bounds.origin);
1194 child_max = child_max.max(&child_bounds.lower_right());
1195 }
1196 (child_max - child_min).into()
1197 };
1198
1199 self.interactivity.prepaint(
1200 global_id,
1201 bounds,
1202 content_size,
1203 cx,
1204 |_style, scroll_offset, hitbox, cx| {
1205 cx.with_element_offset(scroll_offset, |cx| {
1206 for child in &mut self.children {
1207 child.prepaint(cx);
1208 }
1209 });
1210 hitbox
1211 },
1212 )
1213 }
1214
1215 fn paint(
1216 &mut self,
1217 global_id: Option<&GlobalElementId>,
1218 bounds: Bounds<Pixels>,
1219 _request_layout: &mut Self::RequestLayoutState,
1220 hitbox: &mut Option<Hitbox>,
1221 cx: &mut WindowContext,
1222 ) {
1223 self.interactivity
1224 .paint(global_id, bounds, hitbox.as_ref(), cx, |_style, cx| {
1225 for child in &mut self.children {
1226 child.paint(cx);
1227 }
1228 });
1229 }
1230}
1231
1232impl IntoElement for Div {
1233 type Element = Self;
1234
1235 fn into_element(self) -> Self::Element {
1236 self
1237 }
1238}
1239
1240/// The interactivity struct. Powers all of the general-purpose
1241/// interactivity in the `Div` element.
1242#[derive(Default)]
1243pub struct Interactivity {
1244 /// The element ID of the element. In id is required to support a stateful subset of the interactivity such as on_click.
1245 pub element_id: Option<ElementId>,
1246 /// Whether the element was clicked. This will only be present after layout.
1247 pub active: Option<bool>,
1248 /// Whether the element was hovered. This will only be present after paint if an hitbox
1249 /// was created for the interactive element.
1250 pub hovered: Option<bool>,
1251 pub(crate) tooltip_id: Option<TooltipId>,
1252 pub(crate) content_size: Size<Pixels>,
1253 pub(crate) key_context: Option<KeyContext>,
1254 pub(crate) focusable: bool,
1255 pub(crate) tracked_focus_handle: Option<FocusHandle>,
1256 pub(crate) tracked_scroll_handle: Option<ScrollHandle>,
1257 pub(crate) scroll_anchor: Option<ScrollAnchor>,
1258 pub(crate) scroll_offset: Option<Rc<RefCell<Point<Pixels>>>>,
1259 pub(crate) group: Option<SharedString>,
1260 /// The base style of the element, before any modifications are applied
1261 /// by focus, active, etc.
1262 pub base_style: Box<StyleRefinement>,
1263 pub(crate) focus_style: Option<Box<StyleRefinement>>,
1264 pub(crate) in_focus_style: Option<Box<StyleRefinement>>,
1265 pub(crate) hover_style: Option<Box<StyleRefinement>>,
1266 pub(crate) group_hover_style: Option<GroupStyle>,
1267 pub(crate) active_style: Option<Box<StyleRefinement>>,
1268 pub(crate) group_active_style: Option<GroupStyle>,
1269 pub(crate) drag_over_styles: Vec<(
1270 TypeId,
1271 Box<dyn Fn(&dyn Any, &mut WindowContext) -> StyleRefinement>,
1272 )>,
1273 pub(crate) group_drag_over_styles: Vec<(TypeId, GroupStyle)>,
1274 pub(crate) mouse_down_listeners: Vec<MouseDownListener>,
1275 pub(crate) mouse_up_listeners: Vec<MouseUpListener>,
1276 pub(crate) mouse_move_listeners: Vec<MouseMoveListener>,
1277 pub(crate) scroll_wheel_listeners: Vec<ScrollWheelListener>,
1278 pub(crate) key_down_listeners: Vec<KeyDownListener>,
1279 pub(crate) key_up_listeners: Vec<KeyUpListener>,
1280 pub(crate) modifiers_changed_listeners: Vec<ModifiersChangedListener>,
1281 pub(crate) action_listeners: Vec<(TypeId, ActionListener)>,
1282 pub(crate) drop_listeners: Vec<(TypeId, DropListener)>,
1283 pub(crate) can_drop_predicate: Option<CanDropPredicate>,
1284 pub(crate) click_listeners: Vec<ClickListener>,
1285 pub(crate) drag_listener: Option<(Box<dyn Any>, DragListener)>,
1286 pub(crate) hover_listener: Option<Box<dyn Fn(&bool, &mut WindowContext)>>,
1287 pub(crate) tooltip_builder: Option<TooltipBuilder>,
1288 pub(crate) occlude_mouse: bool,
1289
1290 #[cfg(debug_assertions)]
1291 pub(crate) location: Option<core::panic::Location<'static>>,
1292
1293 #[cfg(any(test, feature = "test-support"))]
1294 pub(crate) debug_selector: Option<String>,
1295}
1296
1297impl Interactivity {
1298 /// Layout this element according to this interactivity state's configured styles
1299 pub fn request_layout(
1300 &mut self,
1301 global_id: Option<&GlobalElementId>,
1302 cx: &mut WindowContext,
1303 f: impl FnOnce(Style, &mut WindowContext) -> LayoutId,
1304 ) -> LayoutId {
1305 cx.with_optional_element_state::<InteractiveElementState, _>(
1306 global_id,
1307 |element_state, cx| {
1308 let mut element_state =
1309 element_state.map(|element_state| element_state.unwrap_or_default());
1310
1311 if let Some(element_state) = element_state.as_ref() {
1312 if cx.has_active_drag() {
1313 if let Some(pending_mouse_down) = element_state.pending_mouse_down.as_ref()
1314 {
1315 *pending_mouse_down.borrow_mut() = None;
1316 }
1317 if let Some(clicked_state) = element_state.clicked_state.as_ref() {
1318 *clicked_state.borrow_mut() = ElementClickedState::default();
1319 }
1320 }
1321 }
1322
1323 // Ensure we store a focus handle in our element state if we're focusable.
1324 // If there's an explicit focus handle we're tracking, use that. Otherwise
1325 // create a new handle and store it in the element state, which lives for as
1326 // as frames contain an element with this id.
1327 if self.focusable && self.tracked_focus_handle.is_none() {
1328 if let Some(element_state) = element_state.as_mut() {
1329 self.tracked_focus_handle = Some(
1330 element_state
1331 .focus_handle
1332 .get_or_insert_with(|| cx.focus_handle())
1333 .clone(),
1334 );
1335 }
1336 }
1337
1338 if let Some(scroll_handle) = self.tracked_scroll_handle.as_ref() {
1339 self.scroll_offset = Some(scroll_handle.0.borrow().offset.clone());
1340 } else if self.base_style.overflow.x == Some(Overflow::Scroll)
1341 || self.base_style.overflow.y == Some(Overflow::Scroll)
1342 {
1343 if let Some(element_state) = element_state.as_mut() {
1344 self.scroll_offset = Some(
1345 element_state
1346 .scroll_offset
1347 .get_or_insert_with(Rc::default)
1348 .clone(),
1349 );
1350 }
1351 }
1352
1353 let style = self.compute_style_internal(None, element_state.as_mut(), cx);
1354 let layout_id = f(style, cx);
1355 (layout_id, element_state)
1356 },
1357 )
1358 }
1359
1360 /// Commit the bounds of this element according to this interactivity state's configured styles.
1361 pub fn prepaint<R>(
1362 &mut self,
1363 global_id: Option<&GlobalElementId>,
1364 bounds: Bounds<Pixels>,
1365 content_size: Size<Pixels>,
1366 cx: &mut WindowContext,
1367 f: impl FnOnce(&Style, Point<Pixels>, Option<Hitbox>, &mut WindowContext) -> R,
1368 ) -> R {
1369 self.content_size = content_size;
1370 if let Some(focus_handle) = self.tracked_focus_handle.as_ref() {
1371 cx.set_focus_handle(focus_handle);
1372 }
1373 cx.with_optional_element_state::<InteractiveElementState, _>(
1374 global_id,
1375 |element_state, cx| {
1376 let mut element_state =
1377 element_state.map(|element_state| element_state.unwrap_or_default());
1378 let style = self.compute_style_internal(None, element_state.as_mut(), cx);
1379
1380 if let Some(element_state) = element_state.as_ref() {
1381 if let Some(clicked_state) = element_state.clicked_state.as_ref() {
1382 let clicked_state = clicked_state.borrow();
1383 self.active = Some(clicked_state.element);
1384 }
1385
1386 if let Some(active_tooltip) = element_state.active_tooltip.as_ref() {
1387 if let Some(active_tooltip) = active_tooltip.borrow().as_ref() {
1388 if let Some(tooltip) = active_tooltip.tooltip.clone() {
1389 self.tooltip_id = Some(cx.set_tooltip(tooltip));
1390 }
1391 }
1392 }
1393 }
1394
1395 cx.with_text_style(style.text_style().cloned(), |cx| {
1396 cx.with_content_mask(style.overflow_mask(bounds, cx.rem_size()), |cx| {
1397 let hitbox = if self.should_insert_hitbox(&style) {
1398 Some(cx.insert_hitbox(bounds, self.occlude_mouse))
1399 } else {
1400 None
1401 };
1402
1403 let scroll_offset = self.clamp_scroll_position(bounds, &style, cx);
1404 let result = f(&style, scroll_offset, hitbox, cx);
1405 (result, element_state)
1406 })
1407 })
1408 },
1409 )
1410 }
1411
1412 fn should_insert_hitbox(&self, style: &Style) -> bool {
1413 self.occlude_mouse
1414 || style.mouse_cursor.is_some()
1415 || self.group.is_some()
1416 || self.scroll_offset.is_some()
1417 || self.tracked_focus_handle.is_some()
1418 || self.hover_style.is_some()
1419 || self.group_hover_style.is_some()
1420 || !self.mouse_up_listeners.is_empty()
1421 || !self.mouse_down_listeners.is_empty()
1422 || !self.mouse_move_listeners.is_empty()
1423 || !self.click_listeners.is_empty()
1424 || !self.scroll_wheel_listeners.is_empty()
1425 || self.drag_listener.is_some()
1426 || !self.drop_listeners.is_empty()
1427 || self.tooltip_builder.is_some()
1428 }
1429
1430 fn clamp_scroll_position(
1431 &self,
1432 bounds: Bounds<Pixels>,
1433 style: &Style,
1434 cx: &mut WindowContext,
1435 ) -> Point<Pixels> {
1436 if let Some(scroll_offset) = self.scroll_offset.as_ref() {
1437 if let Some(scroll_handle) = &self.tracked_scroll_handle {
1438 scroll_handle.0.borrow_mut().overflow = style.overflow;
1439 }
1440
1441 let rem_size = cx.rem_size();
1442 let padding_size = size(
1443 style
1444 .padding
1445 .left
1446 .to_pixels(bounds.size.width.into(), rem_size)
1447 + style
1448 .padding
1449 .right
1450 .to_pixels(bounds.size.width.into(), rem_size),
1451 style
1452 .padding
1453 .top
1454 .to_pixels(bounds.size.height.into(), rem_size)
1455 + style
1456 .padding
1457 .bottom
1458 .to_pixels(bounds.size.height.into(), rem_size),
1459 );
1460 let scroll_max = (self.content_size + padding_size - bounds.size).max(&Size::default());
1461 // Clamp scroll offset in case scroll max is smaller now (e.g., if children
1462 // were removed or the bounds became larger).
1463 let mut scroll_offset = scroll_offset.borrow_mut();
1464 scroll_offset.x = scroll_offset.x.clamp(-scroll_max.width, px(0.));
1465 scroll_offset.y = scroll_offset.y.clamp(-scroll_max.height, px(0.));
1466 *scroll_offset
1467 } else {
1468 Point::default()
1469 }
1470 }
1471
1472 /// Paint this element according to this interactivity state's configured styles
1473 /// and bind the element's mouse and keyboard events.
1474 ///
1475 /// content_size is the size of the content of the element, which may be larger than the
1476 /// element's bounds if the element is scrollable.
1477 ///
1478 /// the final computed style will be passed to the provided function, along
1479 /// with the current scroll offset
1480 pub fn paint(
1481 &mut self,
1482 global_id: Option<&GlobalElementId>,
1483 bounds: Bounds<Pixels>,
1484 hitbox: Option<&Hitbox>,
1485 cx: &mut WindowContext,
1486 f: impl FnOnce(&Style, &mut WindowContext),
1487 ) {
1488 self.hovered = hitbox.map(|hitbox| hitbox.is_hovered(cx));
1489 cx.with_optional_element_state::<InteractiveElementState, _>(
1490 global_id,
1491 |element_state, cx| {
1492 let mut element_state =
1493 element_state.map(|element_state| element_state.unwrap_or_default());
1494
1495 let style = self.compute_style_internal(hitbox, element_state.as_mut(), cx);
1496
1497 #[cfg(any(feature = "test-support", test))]
1498 if let Some(debug_selector) = &self.debug_selector {
1499 cx.window
1500 .next_frame
1501 .debug_bounds
1502 .insert(debug_selector.clone(), bounds);
1503 }
1504
1505 self.paint_hover_group_handler(cx);
1506
1507 if style.visibility == Visibility::Hidden {
1508 return ((), element_state);
1509 }
1510
1511 cx.with_element_opacity(style.opacity, |cx| {
1512 style.paint(bounds, cx, |cx: &mut WindowContext| {
1513 cx.with_text_style(style.text_style().cloned(), |cx| {
1514 cx.with_content_mask(
1515 style.overflow_mask(bounds, cx.rem_size()),
1516 |cx| {
1517 if let Some(hitbox) = hitbox {
1518 #[cfg(debug_assertions)]
1519 self.paint_debug_info(global_id, hitbox, &style, cx);
1520
1521 if !cx.has_active_drag() {
1522 if let Some(mouse_cursor) = style.mouse_cursor {
1523 cx.set_cursor_style(mouse_cursor, hitbox);
1524 }
1525 }
1526
1527 if let Some(group) = self.group.clone() {
1528 GroupHitboxes::push(group, hitbox.id, cx);
1529 }
1530
1531 self.paint_mouse_listeners(
1532 hitbox,
1533 element_state.as_mut(),
1534 cx,
1535 );
1536 self.paint_scroll_listener(hitbox, &style, cx);
1537 }
1538
1539 self.paint_keyboard_listeners(cx);
1540 f(&style, cx);
1541
1542 if hitbox.is_some() {
1543 if let Some(group) = self.group.as_ref() {
1544 GroupHitboxes::pop(group, cx);
1545 }
1546 }
1547 },
1548 );
1549 });
1550 });
1551 });
1552
1553 ((), element_state)
1554 },
1555 );
1556 }
1557
1558 #[cfg(debug_assertions)]
1559 fn paint_debug_info(
1560 &self,
1561 global_id: Option<&GlobalElementId>,
1562 hitbox: &Hitbox,
1563 style: &Style,
1564 cx: &mut WindowContext,
1565 ) {
1566 if global_id.is_some()
1567 && (style.debug || style.debug_below || cx.has_global::<crate::DebugBelow>())
1568 && hitbox.is_hovered(cx)
1569 {
1570 const FONT_SIZE: crate::Pixels = crate::Pixels(10.);
1571 let element_id = format!("{:?}", global_id.unwrap());
1572 let str_len = element_id.len();
1573
1574 let render_debug_text = |cx: &mut WindowContext| {
1575 if let Some(text) = cx
1576 .text_system()
1577 .shape_text(
1578 element_id.into(),
1579 FONT_SIZE,
1580 &[cx.text_style().to_run(str_len)],
1581 None,
1582 )
1583 .ok()
1584 .and_then(|mut text| text.pop())
1585 {
1586 text.paint(hitbox.origin, FONT_SIZE, cx).ok();
1587
1588 let text_bounds = crate::Bounds {
1589 origin: hitbox.origin,
1590 size: text.size(FONT_SIZE),
1591 };
1592 if self.location.is_some()
1593 && text_bounds.contains(&cx.mouse_position())
1594 && cx.modifiers().secondary()
1595 {
1596 let secondary_held = cx.modifiers().secondary();
1597 cx.on_key_event({
1598 move |e: &crate::ModifiersChangedEvent, _phase, cx| {
1599 if e.modifiers.secondary() != secondary_held
1600 && text_bounds.contains(&cx.mouse_position())
1601 {
1602 cx.refresh();
1603 }
1604 }
1605 });
1606
1607 let was_hovered = hitbox.is_hovered(cx);
1608 cx.on_mouse_event({
1609 let hitbox = hitbox.clone();
1610 move |_: &MouseMoveEvent, phase, cx| {
1611 if phase == DispatchPhase::Capture {
1612 let hovered = hitbox.is_hovered(cx);
1613 if hovered != was_hovered {
1614 cx.refresh();
1615 }
1616 }
1617 }
1618 });
1619
1620 cx.on_mouse_event({
1621 let hitbox = hitbox.clone();
1622 let location = self.location.unwrap();
1623 move |e: &crate::MouseDownEvent, phase, cx| {
1624 if text_bounds.contains(&e.position)
1625 && phase.capture()
1626 && hitbox.is_hovered(cx)
1627 {
1628 cx.stop_propagation();
1629 let Ok(dir) = std::env::current_dir() else {
1630 return;
1631 };
1632
1633 eprintln!(
1634 "This element was created at:\n{}:{}:{}",
1635 dir.join(location.file()).to_string_lossy(),
1636 location.line(),
1637 location.column()
1638 );
1639 }
1640 }
1641 });
1642 cx.paint_quad(crate::outline(
1643 crate::Bounds {
1644 origin: hitbox.origin
1645 + crate::point(crate::px(0.), FONT_SIZE - px(2.)),
1646 size: crate::Size {
1647 width: text_bounds.size.width,
1648 height: crate::px(1.),
1649 },
1650 },
1651 crate::red(),
1652 ))
1653 }
1654 }
1655 };
1656
1657 cx.with_text_style(
1658 Some(crate::TextStyleRefinement {
1659 color: Some(crate::red()),
1660 line_height: Some(FONT_SIZE.into()),
1661 background_color: Some(crate::white()),
1662 ..Default::default()
1663 }),
1664 render_debug_text,
1665 )
1666 }
1667 }
1668
1669 fn paint_mouse_listeners(
1670 &mut self,
1671 hitbox: &Hitbox,
1672 element_state: Option<&mut InteractiveElementState>,
1673 cx: &mut WindowContext,
1674 ) {
1675 // If this element can be focused, register a mouse down listener
1676 // that will automatically transfer focus when hitting the element.
1677 // This behavior can be suppressed by using `cx.prevent_default()`.
1678 if let Some(focus_handle) = self.tracked_focus_handle.clone() {
1679 let hitbox = hitbox.clone();
1680 cx.on_mouse_event(move |_: &MouseDownEvent, phase, cx| {
1681 if phase == DispatchPhase::Bubble
1682 && hitbox.is_hovered(cx)
1683 && !cx.default_prevented()
1684 {
1685 cx.focus(&focus_handle);
1686 // If there is a parent that is also focusable, prevent it
1687 // from transferring focus because we already did so.
1688 cx.prevent_default();
1689 }
1690 });
1691 }
1692
1693 for listener in self.mouse_down_listeners.drain(..) {
1694 let hitbox = hitbox.clone();
1695 cx.on_mouse_event(move |event: &MouseDownEvent, phase, cx| {
1696 listener(event, phase, &hitbox, cx);
1697 })
1698 }
1699
1700 for listener in self.mouse_up_listeners.drain(..) {
1701 let hitbox = hitbox.clone();
1702 cx.on_mouse_event(move |event: &MouseUpEvent, phase, cx| {
1703 listener(event, phase, &hitbox, cx);
1704 })
1705 }
1706
1707 for listener in self.mouse_move_listeners.drain(..) {
1708 let hitbox = hitbox.clone();
1709 cx.on_mouse_event(move |event: &MouseMoveEvent, phase, cx| {
1710 listener(event, phase, &hitbox, cx);
1711 })
1712 }
1713
1714 for listener in self.scroll_wheel_listeners.drain(..) {
1715 let hitbox = hitbox.clone();
1716 cx.on_mouse_event(move |event: &ScrollWheelEvent, phase, cx| {
1717 listener(event, phase, &hitbox, cx);
1718 })
1719 }
1720
1721 if self.hover_style.is_some()
1722 || self.base_style.mouse_cursor.is_some()
1723 || cx.active_drag.is_some() && !self.drag_over_styles.is_empty()
1724 {
1725 let hitbox = hitbox.clone();
1726 let was_hovered = hitbox.is_hovered(cx);
1727 cx.on_mouse_event(move |_: &MouseMoveEvent, phase, cx| {
1728 let hovered = hitbox.is_hovered(cx);
1729 if phase == DispatchPhase::Capture && hovered != was_hovered {
1730 cx.refresh();
1731 }
1732 });
1733 }
1734
1735 let mut drag_listener = mem::take(&mut self.drag_listener);
1736 let drop_listeners = mem::take(&mut self.drop_listeners);
1737 let click_listeners = mem::take(&mut self.click_listeners);
1738 let can_drop_predicate = mem::take(&mut self.can_drop_predicate);
1739
1740 if !drop_listeners.is_empty() {
1741 let hitbox = hitbox.clone();
1742 cx.on_mouse_event({
1743 move |_: &MouseUpEvent, phase, cx| {
1744 if let Some(drag) = &cx.active_drag {
1745 if phase == DispatchPhase::Bubble && hitbox.is_hovered(cx) {
1746 let drag_state_type = drag.value.as_ref().type_id();
1747 for (drop_state_type, listener) in &drop_listeners {
1748 if *drop_state_type == drag_state_type {
1749 let drag = cx
1750 .active_drag
1751 .take()
1752 .expect("checked for type drag state type above");
1753
1754 let mut can_drop = true;
1755 if let Some(predicate) = &can_drop_predicate {
1756 can_drop = predicate(drag.value.as_ref(), cx);
1757 }
1758
1759 if can_drop {
1760 listener(drag.value.as_ref(), cx);
1761 cx.refresh();
1762 cx.stop_propagation();
1763 }
1764 }
1765 }
1766 }
1767 }
1768 }
1769 });
1770 }
1771
1772 if let Some(element_state) = element_state {
1773 if !click_listeners.is_empty() || drag_listener.is_some() {
1774 let pending_mouse_down = element_state
1775 .pending_mouse_down
1776 .get_or_insert_with(Default::default)
1777 .clone();
1778
1779 let clicked_state = element_state
1780 .clicked_state
1781 .get_or_insert_with(Default::default)
1782 .clone();
1783
1784 cx.on_mouse_event({
1785 let pending_mouse_down = pending_mouse_down.clone();
1786 let hitbox = hitbox.clone();
1787 move |event: &MouseDownEvent, phase, cx| {
1788 if phase == DispatchPhase::Bubble
1789 && event.button == MouseButton::Left
1790 && hitbox.is_hovered(cx)
1791 {
1792 *pending_mouse_down.borrow_mut() = Some(event.clone());
1793 cx.refresh();
1794 }
1795 }
1796 });
1797
1798 cx.on_mouse_event({
1799 let pending_mouse_down = pending_mouse_down.clone();
1800 let hitbox = hitbox.clone();
1801 move |event: &MouseMoveEvent, phase, cx| {
1802 if phase == DispatchPhase::Capture {
1803 return;
1804 }
1805
1806 let mut pending_mouse_down = pending_mouse_down.borrow_mut();
1807 if let Some(mouse_down) = pending_mouse_down.clone() {
1808 if !cx.has_active_drag()
1809 && (event.position - mouse_down.position).magnitude()
1810 > DRAG_THRESHOLD
1811 {
1812 if let Some((drag_value, drag_listener)) = drag_listener.take() {
1813 *clicked_state.borrow_mut() = ElementClickedState::default();
1814 let cursor_offset = event.position - hitbox.origin;
1815 let drag = (drag_listener)(drag_value.as_ref(), cx);
1816 cx.active_drag = Some(AnyDrag {
1817 view: drag,
1818 value: drag_value,
1819 cursor_offset,
1820 });
1821 pending_mouse_down.take();
1822 cx.refresh();
1823 cx.stop_propagation();
1824 }
1825 }
1826 }
1827 }
1828 });
1829
1830 cx.on_mouse_event({
1831 let mut captured_mouse_down = None;
1832 let hitbox = hitbox.clone();
1833 move |event: &MouseUpEvent, phase, cx| match phase {
1834 // Clear the pending mouse down during the capture phase,
1835 // so that it happens even if another event handler stops
1836 // propagation.
1837 DispatchPhase::Capture => {
1838 let mut pending_mouse_down = pending_mouse_down.borrow_mut();
1839 if pending_mouse_down.is_some() && hitbox.is_hovered(cx) {
1840 captured_mouse_down = pending_mouse_down.take();
1841 cx.refresh();
1842 }
1843 }
1844 // Fire click handlers during the bubble phase.
1845 DispatchPhase::Bubble => {
1846 if let Some(mouse_down) = captured_mouse_down.take() {
1847 let mouse_click = ClickEvent {
1848 down: mouse_down,
1849 up: event.clone(),
1850 };
1851 for listener in &click_listeners {
1852 listener(&mouse_click, cx);
1853 }
1854 }
1855 }
1856 }
1857 });
1858 }
1859
1860 if let Some(hover_listener) = self.hover_listener.take() {
1861 let hitbox = hitbox.clone();
1862 let was_hovered = element_state
1863 .hover_state
1864 .get_or_insert_with(Default::default)
1865 .clone();
1866 let has_mouse_down = element_state
1867 .pending_mouse_down
1868 .get_or_insert_with(Default::default)
1869 .clone();
1870
1871 cx.on_mouse_event(move |_: &MouseMoveEvent, phase, cx| {
1872 if phase != DispatchPhase::Bubble {
1873 return;
1874 }
1875 let is_hovered = has_mouse_down.borrow().is_none()
1876 && !cx.has_active_drag()
1877 && hitbox.is_hovered(cx);
1878 let mut was_hovered = was_hovered.borrow_mut();
1879
1880 if is_hovered != *was_hovered {
1881 *was_hovered = is_hovered;
1882 drop(was_hovered);
1883
1884 hover_listener(&is_hovered, cx);
1885 }
1886 });
1887 }
1888
1889 // Ensure to remove active tooltip if tooltip builder is none
1890 if self.tooltip_builder.is_none() {
1891 element_state.active_tooltip.take();
1892 }
1893
1894 if let Some(tooltip_builder) = self.tooltip_builder.take() {
1895 let tooltip_is_hoverable = tooltip_builder.hoverable;
1896 let active_tooltip = element_state
1897 .active_tooltip
1898 .get_or_insert_with(Default::default)
1899 .clone();
1900 let pending_mouse_down = element_state
1901 .pending_mouse_down
1902 .get_or_insert_with(Default::default)
1903 .clone();
1904
1905 cx.on_mouse_event({
1906 let active_tooltip = active_tooltip.clone();
1907 let hitbox = hitbox.clone();
1908 let tooltip_id = self.tooltip_id;
1909 move |_: &MouseMoveEvent, phase, cx| {
1910 let is_hovered =
1911 pending_mouse_down.borrow().is_none() && hitbox.is_hovered(cx);
1912 let tooltip_is_hovered =
1913 tooltip_id.map_or(false, |tooltip_id| tooltip_id.is_hovered(cx));
1914 if !is_hovered && (!tooltip_is_hoverable || !tooltip_is_hovered) {
1915 if active_tooltip.borrow_mut().take().is_some() {
1916 cx.refresh();
1917 }
1918
1919 return;
1920 }
1921
1922 if phase != DispatchPhase::Bubble {
1923 return;
1924 }
1925
1926 if active_tooltip.borrow().is_none() {
1927 let task = cx.spawn({
1928 let active_tooltip = active_tooltip.clone();
1929 let build_tooltip = tooltip_builder.build.clone();
1930 move |mut cx| async move {
1931 cx.background_executor().timer(TOOLTIP_DELAY).await;
1932 cx.update(|cx| {
1933 active_tooltip.borrow_mut().replace(ActiveTooltip {
1934 tooltip: Some(AnyTooltip {
1935 view: build_tooltip(cx),
1936 mouse_position: cx.mouse_position(),
1937 }),
1938 _task: None,
1939 });
1940 cx.refresh();
1941 })
1942 .ok();
1943 }
1944 });
1945 active_tooltip.borrow_mut().replace(ActiveTooltip {
1946 tooltip: None,
1947 _task: Some(task),
1948 });
1949 }
1950 }
1951 });
1952
1953 cx.on_mouse_event({
1954 let active_tooltip = active_tooltip.clone();
1955 let tooltip_id = self.tooltip_id;
1956 move |_: &MouseDownEvent, _, cx| {
1957 let tooltip_is_hovered =
1958 tooltip_id.map_or(false, |tooltip_id| tooltip_id.is_hovered(cx));
1959
1960 if (!tooltip_is_hoverable || !tooltip_is_hovered)
1961 && active_tooltip.borrow_mut().take().is_some()
1962 {
1963 cx.refresh();
1964 }
1965 }
1966 });
1967
1968 cx.on_mouse_event({
1969 let active_tooltip = active_tooltip.clone();
1970 let tooltip_id = self.tooltip_id;
1971 move |_: &ScrollWheelEvent, _, cx| {
1972 let tooltip_is_hovered =
1973 tooltip_id.map_or(false, |tooltip_id| tooltip_id.is_hovered(cx));
1974 if (!tooltip_is_hoverable || !tooltip_is_hovered)
1975 && active_tooltip.borrow_mut().take().is_some()
1976 {
1977 cx.refresh();
1978 }
1979 }
1980 })
1981 }
1982
1983 let active_state = element_state
1984 .clicked_state
1985 .get_or_insert_with(Default::default)
1986 .clone();
1987 if active_state.borrow().is_clicked() {
1988 cx.on_mouse_event(move |_: &MouseUpEvent, phase, cx| {
1989 if phase == DispatchPhase::Capture {
1990 *active_state.borrow_mut() = ElementClickedState::default();
1991 cx.refresh();
1992 }
1993 });
1994 } else {
1995 let active_group_hitbox = self
1996 .group_active_style
1997 .as_ref()
1998 .and_then(|group_active| GroupHitboxes::get(&group_active.group, cx));
1999 let hitbox = hitbox.clone();
2000 cx.on_mouse_event(move |_: &MouseDownEvent, phase, cx| {
2001 if phase == DispatchPhase::Bubble && !cx.default_prevented() {
2002 let group_hovered = active_group_hitbox
2003 .map_or(false, |group_hitbox_id| group_hitbox_id.is_hovered(cx));
2004 let element_hovered = hitbox.is_hovered(cx);
2005 if group_hovered || element_hovered {
2006 *active_state.borrow_mut() = ElementClickedState {
2007 group: group_hovered,
2008 element: element_hovered,
2009 };
2010 cx.refresh();
2011 }
2012 }
2013 });
2014 }
2015 }
2016 }
2017
2018 fn paint_keyboard_listeners(&mut self, cx: &mut WindowContext) {
2019 let key_down_listeners = mem::take(&mut self.key_down_listeners);
2020 let key_up_listeners = mem::take(&mut self.key_up_listeners);
2021 let modifiers_changed_listeners = mem::take(&mut self.modifiers_changed_listeners);
2022 let action_listeners = mem::take(&mut self.action_listeners);
2023 if let Some(context) = self.key_context.clone() {
2024 cx.set_key_context(context);
2025 }
2026
2027 for listener in key_down_listeners {
2028 cx.on_key_event(move |event: &KeyDownEvent, phase, cx| {
2029 listener(event, phase, cx);
2030 })
2031 }
2032
2033 for listener in key_up_listeners {
2034 cx.on_key_event(move |event: &KeyUpEvent, phase, cx| {
2035 listener(event, phase, cx);
2036 })
2037 }
2038
2039 for listener in modifiers_changed_listeners {
2040 cx.on_modifiers_changed(move |event: &ModifiersChangedEvent, cx| {
2041 listener(event, cx);
2042 })
2043 }
2044
2045 for (action_type, listener) in action_listeners {
2046 cx.on_action(action_type, listener)
2047 }
2048 }
2049
2050 fn paint_hover_group_handler(&self, cx: &mut WindowContext) {
2051 let group_hitbox = self
2052 .group_hover_style
2053 .as_ref()
2054 .and_then(|group_hover| GroupHitboxes::get(&group_hover.group, cx));
2055
2056 if let Some(group_hitbox) = group_hitbox {
2057 let was_hovered = group_hitbox.is_hovered(cx);
2058 cx.on_mouse_event(move |_: &MouseMoveEvent, phase, cx| {
2059 let hovered = group_hitbox.is_hovered(cx);
2060 if phase == DispatchPhase::Capture && hovered != was_hovered {
2061 cx.refresh();
2062 }
2063 });
2064 }
2065 }
2066
2067 fn paint_scroll_listener(&self, hitbox: &Hitbox, style: &Style, cx: &mut WindowContext) {
2068 if let Some(scroll_offset) = self.scroll_offset.clone() {
2069 let overflow = style.overflow;
2070 let allow_concurrent_scroll = style.allow_concurrent_scroll;
2071 let line_height = cx.line_height();
2072 let hitbox = hitbox.clone();
2073 cx.on_mouse_event(move |event: &ScrollWheelEvent, phase, cx| {
2074 if phase == DispatchPhase::Bubble && hitbox.is_hovered(cx) {
2075 let mut scroll_offset = scroll_offset.borrow_mut();
2076 let old_scroll_offset = *scroll_offset;
2077 let delta = event.delta.pixel_delta(line_height);
2078
2079 let mut delta_x = Pixels::ZERO;
2080 if overflow.x == Overflow::Scroll {
2081 if !delta.x.is_zero() {
2082 delta_x = delta.x;
2083 } else if overflow.y != Overflow::Scroll {
2084 delta_x = delta.y;
2085 }
2086 }
2087 let mut delta_y = Pixels::ZERO;
2088 if overflow.y == Overflow::Scroll {
2089 if !delta.y.is_zero() {
2090 delta_y = delta.y;
2091 } else if overflow.x != Overflow::Scroll {
2092 delta_y = delta.x;
2093 }
2094 }
2095 if !allow_concurrent_scroll && !delta_x.is_zero() && !delta_y.is_zero() {
2096 if delta_x.abs() > delta_y.abs() {
2097 delta_y = Pixels::ZERO;
2098 } else {
2099 delta_x = Pixels::ZERO;
2100 }
2101 }
2102 scroll_offset.y += delta_y;
2103 scroll_offset.x += delta_x;
2104 cx.stop_propagation();
2105 if *scroll_offset != old_scroll_offset {
2106 cx.refresh();
2107 }
2108 }
2109 });
2110 }
2111 }
2112
2113 /// Compute the visual style for this element, based on the current bounds and the element's state.
2114 pub fn compute_style(
2115 &self,
2116 global_id: Option<&GlobalElementId>,
2117 hitbox: Option<&Hitbox>,
2118 cx: &mut WindowContext,
2119 ) -> Style {
2120 cx.with_optional_element_state(global_id, |element_state, cx| {
2121 let mut element_state =
2122 element_state.map(|element_state| element_state.unwrap_or_default());
2123 let style = self.compute_style_internal(hitbox, element_state.as_mut(), cx);
2124 (style, element_state)
2125 })
2126 }
2127
2128 /// Called from internal methods that have already called with_element_state.
2129 fn compute_style_internal(
2130 &self,
2131 hitbox: Option<&Hitbox>,
2132 element_state: Option<&mut InteractiveElementState>,
2133 cx: &mut WindowContext,
2134 ) -> Style {
2135 let mut style = Style::default();
2136 style.refine(&self.base_style);
2137
2138 if let Some(focus_handle) = self.tracked_focus_handle.as_ref() {
2139 if let Some(in_focus_style) = self.in_focus_style.as_ref() {
2140 if focus_handle.within_focused(cx) {
2141 style.refine(in_focus_style);
2142 }
2143 }
2144
2145 if let Some(focus_style) = self.focus_style.as_ref() {
2146 if focus_handle.is_focused(cx) {
2147 style.refine(focus_style);
2148 }
2149 }
2150 }
2151
2152 if let Some(hitbox) = hitbox {
2153 if !cx.has_active_drag() {
2154 if let Some(group_hover) = self.group_hover_style.as_ref() {
2155 if let Some(group_hitbox_id) =
2156 GroupHitboxes::get(&group_hover.group, cx.deref_mut())
2157 {
2158 if group_hitbox_id.is_hovered(cx) {
2159 style.refine(&group_hover.style);
2160 }
2161 }
2162 }
2163
2164 if let Some(hover_style) = self.hover_style.as_ref() {
2165 if hitbox.is_hovered(cx) {
2166 style.refine(hover_style);
2167 }
2168 }
2169 }
2170
2171 if let Some(drag) = cx.active_drag.take() {
2172 let mut can_drop = true;
2173 if let Some(can_drop_predicate) = &self.can_drop_predicate {
2174 can_drop = can_drop_predicate(drag.value.as_ref(), cx);
2175 }
2176
2177 if can_drop {
2178 for (state_type, group_drag_style) in &self.group_drag_over_styles {
2179 if let Some(group_hitbox_id) =
2180 GroupHitboxes::get(&group_drag_style.group, cx.deref_mut())
2181 {
2182 if *state_type == drag.value.as_ref().type_id()
2183 && group_hitbox_id.is_hovered(cx)
2184 {
2185 style.refine(&group_drag_style.style);
2186 }
2187 }
2188 }
2189
2190 for (state_type, build_drag_over_style) in &self.drag_over_styles {
2191 if *state_type == drag.value.as_ref().type_id() && hitbox.is_hovered(cx) {
2192 style.refine(&build_drag_over_style(drag.value.as_ref(), cx));
2193 }
2194 }
2195 }
2196
2197 cx.active_drag = Some(drag);
2198 }
2199 }
2200
2201 if let Some(element_state) = element_state {
2202 let clicked_state = element_state
2203 .clicked_state
2204 .get_or_insert_with(Default::default)
2205 .borrow();
2206 if clicked_state.group {
2207 if let Some(group) = self.group_active_style.as_ref() {
2208 style.refine(&group.style)
2209 }
2210 }
2211
2212 if let Some(active_style) = self.active_style.as_ref() {
2213 if clicked_state.element {
2214 style.refine(active_style)
2215 }
2216 }
2217 }
2218
2219 style
2220 }
2221}
2222
2223/// The per-frame state of an interactive element. Used for tracking stateful interactions like clicks
2224/// and scroll offsets.
2225#[derive(Default)]
2226pub struct InteractiveElementState {
2227 pub(crate) focus_handle: Option<FocusHandle>,
2228 pub(crate) clicked_state: Option<Rc<RefCell<ElementClickedState>>>,
2229 pub(crate) hover_state: Option<Rc<RefCell<bool>>>,
2230 pub(crate) pending_mouse_down: Option<Rc<RefCell<Option<MouseDownEvent>>>>,
2231 pub(crate) scroll_offset: Option<Rc<RefCell<Point<Pixels>>>>,
2232 pub(crate) active_tooltip: Option<Rc<RefCell<Option<ActiveTooltip>>>>,
2233}
2234
2235/// The current active tooltip
2236pub struct ActiveTooltip {
2237 pub(crate) tooltip: Option<AnyTooltip>,
2238 pub(crate) _task: Option<Task<()>>,
2239}
2240
2241/// Whether or not the element or a group that contains it is clicked by the mouse.
2242#[derive(Copy, Clone, Default, Eq, PartialEq)]
2243pub struct ElementClickedState {
2244 /// True if this element's group has been clicked, false otherwise
2245 pub group: bool,
2246
2247 /// True if this element has been clicked, false otherwise
2248 pub element: bool,
2249}
2250
2251impl ElementClickedState {
2252 fn is_clicked(&self) -> bool {
2253 self.group || self.element
2254 }
2255}
2256
2257#[derive(Default)]
2258pub(crate) struct GroupHitboxes(HashMap<SharedString, SmallVec<[HitboxId; 1]>>);
2259
2260impl Global for GroupHitboxes {}
2261
2262impl GroupHitboxes {
2263 pub fn get(name: &SharedString, cx: &mut AppContext) -> Option<HitboxId> {
2264 cx.default_global::<Self>()
2265 .0
2266 .get(name)
2267 .and_then(|bounds_stack| bounds_stack.last())
2268 .cloned()
2269 }
2270
2271 pub fn push(name: SharedString, hitbox_id: HitboxId, cx: &mut AppContext) {
2272 cx.default_global::<Self>()
2273 .0
2274 .entry(name)
2275 .or_default()
2276 .push(hitbox_id);
2277 }
2278
2279 pub fn pop(name: &SharedString, cx: &mut AppContext) {
2280 cx.default_global::<Self>().0.get_mut(name).unwrap().pop();
2281 }
2282}
2283
2284/// A wrapper around an element that can be focused.
2285pub struct Focusable<E> {
2286 /// The element that is focusable
2287 pub element: E,
2288}
2289
2290impl<E: InteractiveElement> FocusableElement for Focusable<E> {}
2291
2292impl<E> InteractiveElement for Focusable<E>
2293where
2294 E: InteractiveElement,
2295{
2296 fn interactivity(&mut self) -> &mut Interactivity {
2297 self.element.interactivity()
2298 }
2299}
2300
2301impl<E: StatefulInteractiveElement> StatefulInteractiveElement for Focusable<E> {}
2302
2303impl<E> Styled for Focusable<E>
2304where
2305 E: Styled,
2306{
2307 fn style(&mut self) -> &mut StyleRefinement {
2308 self.element.style()
2309 }
2310}
2311
2312impl<E> Element for Focusable<E>
2313where
2314 E: Element,
2315{
2316 type RequestLayoutState = E::RequestLayoutState;
2317 type PrepaintState = E::PrepaintState;
2318
2319 fn id(&self) -> Option<ElementId> {
2320 self.element.id()
2321 }
2322
2323 fn request_layout(
2324 &mut self,
2325 id: Option<&GlobalElementId>,
2326 cx: &mut WindowContext,
2327 ) -> (LayoutId, Self::RequestLayoutState) {
2328 self.element.request_layout(id, cx)
2329 }
2330
2331 fn prepaint(
2332 &mut self,
2333 id: Option<&GlobalElementId>,
2334 bounds: Bounds<Pixels>,
2335 state: &mut Self::RequestLayoutState,
2336 cx: &mut WindowContext,
2337 ) -> E::PrepaintState {
2338 self.element.prepaint(id, bounds, state, cx)
2339 }
2340
2341 fn paint(
2342 &mut self,
2343 id: Option<&GlobalElementId>,
2344 bounds: Bounds<Pixels>,
2345 request_layout: &mut Self::RequestLayoutState,
2346 prepaint: &mut Self::PrepaintState,
2347 cx: &mut WindowContext,
2348 ) {
2349 self.element.paint(id, bounds, request_layout, prepaint, cx)
2350 }
2351}
2352
2353impl<E> IntoElement for Focusable<E>
2354where
2355 E: IntoElement,
2356{
2357 type Element = E::Element;
2358
2359 fn into_element(self) -> Self::Element {
2360 self.element.into_element()
2361 }
2362}
2363
2364impl<E> ParentElement for Focusable<E>
2365where
2366 E: ParentElement,
2367{
2368 fn extend(&mut self, elements: impl IntoIterator<Item = AnyElement>) {
2369 self.element.extend(elements)
2370 }
2371}
2372
2373/// A wrapper around an element that can store state, produced after assigning an ElementId.
2374pub struct Stateful<E> {
2375 element: E,
2376}
2377
2378impl<E> Styled for Stateful<E>
2379where
2380 E: Styled,
2381{
2382 fn style(&mut self) -> &mut StyleRefinement {
2383 self.element.style()
2384 }
2385}
2386
2387impl<E> StatefulInteractiveElement for Stateful<E>
2388where
2389 E: Element,
2390 Self: InteractiveElement,
2391{
2392}
2393
2394impl<E> InteractiveElement for Stateful<E>
2395where
2396 E: InteractiveElement,
2397{
2398 fn interactivity(&mut self) -> &mut Interactivity {
2399 self.element.interactivity()
2400 }
2401}
2402
2403impl<E: FocusableElement> FocusableElement for Stateful<E> {}
2404
2405impl<E> Element for Stateful<E>
2406where
2407 E: Element,
2408{
2409 type RequestLayoutState = E::RequestLayoutState;
2410 type PrepaintState = E::PrepaintState;
2411
2412 fn id(&self) -> Option<ElementId> {
2413 self.element.id()
2414 }
2415
2416 fn request_layout(
2417 &mut self,
2418 id: Option<&GlobalElementId>,
2419 cx: &mut WindowContext,
2420 ) -> (LayoutId, Self::RequestLayoutState) {
2421 self.element.request_layout(id, cx)
2422 }
2423
2424 fn prepaint(
2425 &mut self,
2426 id: Option<&GlobalElementId>,
2427 bounds: Bounds<Pixels>,
2428 state: &mut Self::RequestLayoutState,
2429 cx: &mut WindowContext,
2430 ) -> E::PrepaintState {
2431 self.element.prepaint(id, bounds, state, cx)
2432 }
2433
2434 fn paint(
2435 &mut self,
2436 id: Option<&GlobalElementId>,
2437 bounds: Bounds<Pixels>,
2438 request_layout: &mut Self::RequestLayoutState,
2439 prepaint: &mut Self::PrepaintState,
2440 cx: &mut WindowContext,
2441 ) {
2442 self.element.paint(id, bounds, request_layout, prepaint, cx);
2443 }
2444}
2445
2446impl<E> IntoElement for Stateful<E>
2447where
2448 E: Element,
2449{
2450 type Element = Self;
2451
2452 fn into_element(self) -> Self::Element {
2453 self
2454 }
2455}
2456
2457impl<E> ParentElement for Stateful<E>
2458where
2459 E: ParentElement,
2460{
2461 fn extend(&mut self, elements: impl IntoIterator<Item = AnyElement>) {
2462 self.element.extend(elements)
2463 }
2464}
2465
2466/// Represents an element that can be scrolled *to* in its parent element.
2467///
2468/// Contrary to [ScrollHandle::scroll_to_item], an anchored element does not have to be an immediate child of the parent.
2469#[derive(Clone)]
2470pub struct ScrollAnchor {
2471 handle: ScrollHandle,
2472 last_origin: Rc<RefCell<Point<Pixels>>>,
2473}
2474
2475impl ScrollAnchor {
2476 /// Creates a [ScrollAnchor] associated with a given [ScrollHandle].
2477 pub fn for_handle(handle: ScrollHandle) -> Self {
2478 Self {
2479 handle,
2480 last_origin: Default::default(),
2481 }
2482 }
2483 /// Request scroll to this item on the next frame.
2484 pub fn scroll_to(&self, cx: &mut WindowContext<'_>) {
2485 let this = self.clone();
2486
2487 cx.on_next_frame(move |_| {
2488 let viewport_bounds = this.handle.bounds();
2489 let self_bounds = *this.last_origin.borrow();
2490 this.handle.set_offset(viewport_bounds.origin - self_bounds);
2491 });
2492 }
2493}
2494#[derive(Default, Debug)]
2495struct ScrollHandleState {
2496 offset: Rc<RefCell<Point<Pixels>>>,
2497 bounds: Bounds<Pixels>,
2498 child_bounds: Vec<Bounds<Pixels>>,
2499 requested_scroll_top: Option<(usize, Pixels)>,
2500 overflow: Point<Overflow>,
2501}
2502
2503/// A handle to the scrollable aspects of an element.
2504/// Used for accessing scroll state, like the current scroll offset,
2505/// and for mutating the scroll state, like scrolling to a specific child.
2506#[derive(Clone, Debug)]
2507pub struct ScrollHandle(Rc<RefCell<ScrollHandleState>>);
2508
2509impl Default for ScrollHandle {
2510 fn default() -> Self {
2511 Self::new()
2512 }
2513}
2514
2515impl ScrollHandle {
2516 /// Construct a new scroll handle.
2517 pub fn new() -> Self {
2518 Self(Rc::default())
2519 }
2520
2521 /// Get the current scroll offset.
2522 pub fn offset(&self) -> Point<Pixels> {
2523 *self.0.borrow().offset.borrow()
2524 }
2525
2526 /// Get the top child that's scrolled into view.
2527 pub fn top_item(&self) -> usize {
2528 let state = self.0.borrow();
2529 let top = state.bounds.top() - state.offset.borrow().y;
2530
2531 match state.child_bounds.binary_search_by(|bounds| {
2532 if top < bounds.top() {
2533 Ordering::Greater
2534 } else if top > bounds.bottom() {
2535 Ordering::Less
2536 } else {
2537 Ordering::Equal
2538 }
2539 }) {
2540 Ok(ix) => ix,
2541 Err(ix) => ix.min(state.child_bounds.len().saturating_sub(1)),
2542 }
2543 }
2544
2545 /// Return the bounds into which this child is painted
2546 pub fn bounds(&self) -> Bounds<Pixels> {
2547 self.0.borrow().bounds
2548 }
2549
2550 /// Set the bounds into which this child is painted
2551 pub(super) fn set_bounds(&self, bounds: Bounds<Pixels>) {
2552 self.0.borrow_mut().bounds = bounds;
2553 }
2554
2555 /// Get the bounds for a specific child.
2556 pub fn bounds_for_item(&self, ix: usize) -> Option<Bounds<Pixels>> {
2557 self.0.borrow().child_bounds.get(ix).cloned()
2558 }
2559
2560 /// scroll_to_item scrolls the minimal amount to ensure that the child is
2561 /// fully visible
2562 pub fn scroll_to_item(&self, ix: usize) {
2563 let state = self.0.borrow();
2564
2565 let Some(bounds) = state.child_bounds.get(ix) else {
2566 return;
2567 };
2568
2569 let mut scroll_offset = state.offset.borrow_mut();
2570
2571 if state.overflow.y == Overflow::Scroll {
2572 if bounds.top() + scroll_offset.y < state.bounds.top() {
2573 scroll_offset.y = state.bounds.top() - bounds.top();
2574 } else if bounds.bottom() + scroll_offset.y > state.bounds.bottom() {
2575 scroll_offset.y = state.bounds.bottom() - bounds.bottom();
2576 }
2577 }
2578
2579 if state.overflow.x == Overflow::Scroll {
2580 if bounds.left() + scroll_offset.x < state.bounds.left() {
2581 scroll_offset.x = state.bounds.left() - bounds.left();
2582 } else if bounds.right() + scroll_offset.x > state.bounds.right() {
2583 scroll_offset.x = state.bounds.right() - bounds.right();
2584 }
2585 }
2586 }
2587
2588 /// Set the offset explicitly. The offset is the distance from the top left of the
2589 /// parent container to the top left of the first child.
2590 /// As you scroll further down the offset becomes more negative.
2591 pub fn set_offset(&self, mut position: Point<Pixels>) {
2592 let state = self.0.borrow();
2593 *state.offset.borrow_mut() = position;
2594 }
2595
2596 /// Get the logical scroll top, based on a child index and a pixel offset.
2597 pub fn logical_scroll_top(&self) -> (usize, Pixels) {
2598 let ix = self.top_item();
2599 let state = self.0.borrow();
2600
2601 if let Some(child_bounds) = state.child_bounds.get(ix) {
2602 (
2603 ix,
2604 child_bounds.top() + state.offset.borrow().y - state.bounds.top(),
2605 )
2606 } else {
2607 (ix, px(0.))
2608 }
2609 }
2610
2611 /// Set the logical scroll top, based on a child index and a pixel offset.
2612 pub fn set_logical_scroll_top(&self, ix: usize, px: Pixels) {
2613 self.0.borrow_mut().requested_scroll_top = Some((ix, px));
2614 }
2615
2616 /// Get the count of children for scrollable item.
2617 pub fn children_count(&self) -> usize {
2618 self.0.borrow().child_bounds.len()
2619 }
2620}