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 AbsoluteLength, Action, AnyDrag, AnyElement, AnyTooltip, AnyView, App, Bounds, ClickEvent,
20 DispatchPhase, Display, Element, ElementId, Entity, FocusHandle, Global, GlobalElementId,
21 Hitbox, HitboxBehavior, HitboxId, InspectorElementId, IntoElement, IsZero, KeyContext,
22 KeyDownEvent, KeyUpEvent, KeyboardButton, KeyboardClickEvent, LayoutId, ModifiersChangedEvent,
23 MouseButton, MouseClickEvent, MouseDownEvent, MouseMoveEvent, MousePressureEvent, MouseUpEvent,
24 Overflow, ParentElement, Pixels, Point, Render, ScrollWheelEvent, SharedString, Size, Style,
25 StyleRefinement, Styled, Task, TooltipId, Visibility, Window, WindowControlArea, point, px,
26 size,
27};
28use collections::HashMap;
29use refineable::Refineable;
30use smallvec::SmallVec;
31use stacksafe::{StackSafe, stacksafe};
32use std::{
33 any::{Any, TypeId},
34 cell::RefCell,
35 cmp::Ordering,
36 fmt::Debug,
37 marker::PhantomData,
38 mem,
39 rc::Rc,
40 sync::Arc,
41 time::Duration,
42};
43use util::ResultExt;
44
45use super::ImageCacheProvider;
46
47const DRAG_THRESHOLD: f64 = 2.;
48const TOOLTIP_SHOW_DELAY: Duration = Duration::from_millis(500);
49const HOVERABLE_TOOLTIP_HIDE_DELAY: Duration = Duration::from_millis(500);
50
51/// The styling information for a given group.
52pub struct GroupStyle {
53 /// The identifier for this group.
54 pub group: SharedString,
55
56 /// The specific style refinement that this group would apply
57 /// to its children.
58 pub style: Box<StyleRefinement>,
59}
60
61/// An event for when a drag is moving over this element, with the given state type.
62pub struct DragMoveEvent<T> {
63 /// The mouse move event that triggered this drag move event.
64 pub event: MouseMoveEvent,
65
66 /// The bounds of this element.
67 pub bounds: Bounds<Pixels>,
68 drag: PhantomData<T>,
69 dragged_item: Arc<dyn Any>,
70}
71
72impl<T: 'static> DragMoveEvent<T> {
73 /// Returns the drag state for this event.
74 pub fn drag<'b>(&self, cx: &'b App) -> &'b T {
75 cx.active_drag
76 .as_ref()
77 .and_then(|drag| drag.value.downcast_ref::<T>())
78 .expect("DragMoveEvent is only valid when the stored active drag is of the same type.")
79 }
80
81 /// An item that is about to be dropped.
82 pub fn dragged_item(&self) -> &dyn Any {
83 self.dragged_item.as_ref()
84 }
85}
86
87impl Interactivity {
88 /// Create an `Interactivity`, capturing the caller location in debug mode.
89 #[cfg(any(feature = "inspector", debug_assertions))]
90 #[track_caller]
91 pub fn new() -> Interactivity {
92 Interactivity {
93 source_location: Some(core::panic::Location::caller()),
94 ..Default::default()
95 }
96 }
97
98 /// Create an `Interactivity`, capturing the caller location in debug mode.
99 #[cfg(not(any(feature = "inspector", debug_assertions)))]
100 pub fn new() -> Interactivity {
101 Interactivity::default()
102 }
103
104 /// Gets the source location of construction. Returns `None` when not in debug mode.
105 pub fn source_location(&self) -> Option<&'static std::panic::Location<'static>> {
106 #[cfg(any(feature = "inspector", debug_assertions))]
107 {
108 self.source_location
109 }
110
111 #[cfg(not(any(feature = "inspector", debug_assertions)))]
112 {
113 None
114 }
115 }
116
117 /// Bind the given callback to the mouse down event for the given mouse button, during the bubble phase.
118 /// The imperative API equivalent of [`InteractiveElement::on_mouse_down`].
119 ///
120 /// See [`Context::listener`](crate::Context::listener) to get access to the view state from this callback.
121 pub fn on_mouse_down(
122 &mut self,
123 button: MouseButton,
124 listener: impl Fn(&MouseDownEvent, &mut Window, &mut App) + 'static,
125 ) {
126 self.mouse_down_listeners
127 .push(Box::new(move |event, phase, hitbox, window, cx| {
128 if phase == DispatchPhase::Bubble
129 && event.button == button
130 && hitbox.is_hovered(window)
131 {
132 (listener)(event, window, cx)
133 }
134 }));
135 }
136
137 /// Bind the given callback to the mouse down event for any button, during the capture phase.
138 /// The imperative API equivalent of [`InteractiveElement::capture_any_mouse_down`].
139 ///
140 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
141 pub fn capture_any_mouse_down(
142 &mut self,
143 listener: impl Fn(&MouseDownEvent, &mut Window, &mut App) + 'static,
144 ) {
145 self.mouse_down_listeners
146 .push(Box::new(move |event, phase, hitbox, window, cx| {
147 if phase == DispatchPhase::Capture && hitbox.is_hovered(window) {
148 (listener)(event, window, cx)
149 }
150 }));
151 }
152
153 /// Bind the given callback to the mouse down event for any button, during the bubble phase.
154 /// The imperative API equivalent to [`InteractiveElement::on_any_mouse_down`].
155 ///
156 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
157 pub fn on_any_mouse_down(
158 &mut self,
159 listener: impl Fn(&MouseDownEvent, &mut Window, &mut App) + 'static,
160 ) {
161 self.mouse_down_listeners
162 .push(Box::new(move |event, phase, hitbox, window, cx| {
163 if phase == DispatchPhase::Bubble && hitbox.is_hovered(window) {
164 (listener)(event, window, cx)
165 }
166 }));
167 }
168
169 /// Bind the given callback to the mouse pressure event, during the bubble phase
170 /// the imperative API equivalent to [`InteractiveElement::on_mouse_pressure`].
171 ///
172 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
173 pub fn on_mouse_pressure(
174 &mut self,
175 listener: impl Fn(&MousePressureEvent, &mut Window, &mut App) + 'static,
176 ) {
177 self.mouse_pressure_listeners
178 .push(Box::new(move |event, phase, hitbox, window, cx| {
179 if phase == DispatchPhase::Bubble && hitbox.is_hovered(window) {
180 (listener)(event, window, cx)
181 }
182 }));
183 }
184
185 /// Bind the given callback to the mouse pressure event, during the capture phase
186 /// the imperative API equivalent to [`InteractiveElement::on_mouse_pressure`].
187 ///
188 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
189 pub fn capture_mouse_pressure(
190 &mut self,
191 listener: impl Fn(&MousePressureEvent, &mut Window, &mut App) + 'static,
192 ) {
193 self.mouse_pressure_listeners
194 .push(Box::new(move |event, phase, hitbox, window, cx| {
195 if phase == DispatchPhase::Capture && hitbox.is_hovered(window) {
196 (listener)(event, window, cx)
197 }
198 }));
199 }
200
201 /// Bind the given callback to the mouse up event for the given button, during the bubble phase.
202 /// The imperative API equivalent to [`InteractiveElement::on_mouse_up`].
203 ///
204 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
205 pub fn on_mouse_up(
206 &mut self,
207 button: MouseButton,
208 listener: impl Fn(&MouseUpEvent, &mut Window, &mut App) + 'static,
209 ) {
210 self.mouse_up_listeners
211 .push(Box::new(move |event, phase, hitbox, window, cx| {
212 if phase == DispatchPhase::Bubble
213 && event.button == button
214 && hitbox.is_hovered(window)
215 {
216 (listener)(event, window, cx)
217 }
218 }));
219 }
220
221 /// Bind the given callback to the mouse up event for any button, during the capture phase.
222 /// The imperative API equivalent to [`InteractiveElement::capture_any_mouse_up`].
223 ///
224 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
225 pub fn capture_any_mouse_up(
226 &mut self,
227 listener: impl Fn(&MouseUpEvent, &mut Window, &mut App) + 'static,
228 ) {
229 self.mouse_up_listeners
230 .push(Box::new(move |event, phase, hitbox, window, cx| {
231 if phase == DispatchPhase::Capture && hitbox.is_hovered(window) {
232 (listener)(event, window, cx)
233 }
234 }));
235 }
236
237 /// Bind the given callback to the mouse up event for any button, during the bubble phase.
238 /// The imperative API equivalent to [`Interactivity::on_any_mouse_up`].
239 ///
240 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
241 pub fn on_any_mouse_up(
242 &mut self,
243 listener: impl Fn(&MouseUpEvent, &mut Window, &mut App) + 'static,
244 ) {
245 self.mouse_up_listeners
246 .push(Box::new(move |event, phase, hitbox, window, cx| {
247 if phase == DispatchPhase::Bubble && hitbox.is_hovered(window) {
248 (listener)(event, window, cx)
249 }
250 }));
251 }
252
253 /// Bind the given callback to the mouse down event, on any button, during the capture phase,
254 /// when the mouse is outside of the bounds of this element.
255 /// The imperative API equivalent to [`InteractiveElement::on_mouse_down_out`].
256 ///
257 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
258 pub fn on_mouse_down_out(
259 &mut self,
260 listener: impl Fn(&MouseDownEvent, &mut Window, &mut App) + 'static,
261 ) {
262 self.mouse_down_listeners
263 .push(Box::new(move |event, phase, hitbox, window, cx| {
264 if phase == DispatchPhase::Capture && !hitbox.contains(&window.mouse_position()) {
265 (listener)(event, window, cx)
266 }
267 }));
268 }
269
270 /// Bind the given callback to the mouse up event, for the given button, during the capture phase,
271 /// when the mouse is outside of the bounds of this element.
272 /// The imperative API equivalent to [`InteractiveElement::on_mouse_up_out`].
273 ///
274 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
275 pub fn on_mouse_up_out(
276 &mut self,
277 button: MouseButton,
278 listener: impl Fn(&MouseUpEvent, &mut Window, &mut App) + 'static,
279 ) {
280 self.mouse_up_listeners
281 .push(Box::new(move |event, phase, hitbox, window, cx| {
282 if phase == DispatchPhase::Capture
283 && event.button == button
284 && !hitbox.is_hovered(window)
285 {
286 (listener)(event, window, cx);
287 }
288 }));
289 }
290
291 /// Bind the given callback to the mouse move event, during the bubble phase.
292 /// The imperative API equivalent to [`InteractiveElement::on_mouse_move`].
293 ///
294 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
295 pub fn on_mouse_move(
296 &mut self,
297 listener: impl Fn(&MouseMoveEvent, &mut Window, &mut App) + 'static,
298 ) {
299 self.mouse_move_listeners
300 .push(Box::new(move |event, phase, hitbox, window, cx| {
301 if phase == DispatchPhase::Bubble && hitbox.is_hovered(window) {
302 (listener)(event, window, cx);
303 }
304 }));
305 }
306
307 /// Bind the given callback to the mouse drag event of the given type. Note that this
308 /// will be called for all move events, inside or outside of this element, as long as the
309 /// drag was started with this element under the mouse. Useful for implementing draggable
310 /// UIs that don't conform to a drag and drop style interaction, like resizing.
311 /// The imperative API equivalent to [`InteractiveElement::on_drag_move`].
312 ///
313 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
314 pub fn on_drag_move<T>(
315 &mut self,
316 listener: impl Fn(&DragMoveEvent<T>, &mut Window, &mut App) + 'static,
317 ) where
318 T: 'static,
319 {
320 self.mouse_move_listeners
321 .push(Box::new(move |event, phase, hitbox, window, cx| {
322 if phase == DispatchPhase::Capture
323 && let Some(drag) = &cx.active_drag
324 && drag.value.as_ref().type_id() == TypeId::of::<T>()
325 {
326 (listener)(
327 &DragMoveEvent {
328 event: event.clone(),
329 bounds: hitbox.bounds,
330 drag: PhantomData,
331 dragged_item: Arc::clone(&drag.value),
332 },
333 window,
334 cx,
335 );
336 }
337 }));
338 }
339
340 /// Bind the given callback to scroll wheel events during the bubble phase.
341 /// The imperative API equivalent to [`InteractiveElement::on_scroll_wheel`].
342 ///
343 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
344 pub fn on_scroll_wheel(
345 &mut self,
346 listener: impl Fn(&ScrollWheelEvent, &mut Window, &mut App) + 'static,
347 ) {
348 self.scroll_wheel_listeners
349 .push(Box::new(move |event, phase, hitbox, window, cx| {
350 if phase == DispatchPhase::Bubble && hitbox.should_handle_scroll(window) {
351 (listener)(event, window, cx);
352 }
353 }));
354 }
355
356 /// Bind the given callback to an action dispatch during the capture phase.
357 /// The imperative API equivalent to [`InteractiveElement::capture_action`].
358 ///
359 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
360 pub fn capture_action<A: Action>(
361 &mut self,
362 listener: impl Fn(&A, &mut Window, &mut App) + 'static,
363 ) {
364 self.action_listeners.push((
365 TypeId::of::<A>(),
366 Box::new(move |action, phase, window, cx| {
367 let action = action.downcast_ref().unwrap();
368 if phase == DispatchPhase::Capture {
369 (listener)(action, window, cx)
370 } else {
371 cx.propagate();
372 }
373 }),
374 ));
375 }
376
377 /// Bind the given callback to an action dispatch during the bubble phase.
378 /// The imperative API equivalent to [`InteractiveElement::on_action`].
379 ///
380 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
381 pub fn on_action<A: Action>(&mut self, listener: impl Fn(&A, &mut Window, &mut App) + 'static) {
382 self.action_listeners.push((
383 TypeId::of::<A>(),
384 Box::new(move |action, phase, window, cx| {
385 let action = action.downcast_ref().unwrap();
386 if phase == DispatchPhase::Bubble {
387 (listener)(action, window, cx)
388 }
389 }),
390 ));
391 }
392
393 /// Bind the given callback to an action dispatch, based on a dynamic action parameter
394 /// instead of a type parameter. Useful for component libraries that want to expose
395 /// action bindings to their users.
396 /// The imperative API equivalent to [`InteractiveElement::on_boxed_action`].
397 ///
398 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
399 pub fn on_boxed_action(
400 &mut self,
401 action: &dyn Action,
402 listener: impl Fn(&dyn Action, &mut Window, &mut App) + 'static,
403 ) {
404 let action = action.boxed_clone();
405 self.action_listeners.push((
406 (*action).type_id(),
407 Box::new(move |_, phase, window, cx| {
408 if phase == DispatchPhase::Bubble {
409 (listener)(&*action, window, cx)
410 }
411 }),
412 ));
413 }
414
415 /// Bind the given callback to key down events during the bubble phase.
416 /// The imperative API equivalent to [`InteractiveElement::on_key_down`].
417 ///
418 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
419 pub fn on_key_down(
420 &mut self,
421 listener: impl Fn(&KeyDownEvent, &mut Window, &mut App) + 'static,
422 ) {
423 self.key_down_listeners
424 .push(Box::new(move |event, phase, window, cx| {
425 if phase == DispatchPhase::Bubble {
426 (listener)(event, window, cx)
427 }
428 }));
429 }
430
431 /// Bind the given callback to key down events during the capture phase.
432 /// The imperative API equivalent to [`InteractiveElement::capture_key_down`].
433 ///
434 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
435 pub fn capture_key_down(
436 &mut self,
437 listener: impl Fn(&KeyDownEvent, &mut Window, &mut App) + 'static,
438 ) {
439 self.key_down_listeners
440 .push(Box::new(move |event, phase, window, cx| {
441 if phase == DispatchPhase::Capture {
442 listener(event, window, cx)
443 }
444 }));
445 }
446
447 /// Bind the given callback to key up events during the bubble phase.
448 /// The imperative API equivalent to [`InteractiveElement::on_key_up`].
449 ///
450 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
451 pub fn on_key_up(&mut self, listener: impl Fn(&KeyUpEvent, &mut Window, &mut App) + 'static) {
452 self.key_up_listeners
453 .push(Box::new(move |event, phase, window, cx| {
454 if phase == DispatchPhase::Bubble {
455 listener(event, window, cx)
456 }
457 }));
458 }
459
460 /// Bind the given callback to key up events during the capture phase.
461 /// The imperative API equivalent to [`InteractiveElement::on_key_up`].
462 ///
463 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
464 pub fn capture_key_up(
465 &mut self,
466 listener: impl Fn(&KeyUpEvent, &mut Window, &mut App) + 'static,
467 ) {
468 self.key_up_listeners
469 .push(Box::new(move |event, phase, window, cx| {
470 if phase == DispatchPhase::Capture {
471 listener(event, window, cx)
472 }
473 }));
474 }
475
476 /// Bind the given callback to modifiers changing events.
477 /// The imperative API equivalent to [`InteractiveElement::on_modifiers_changed`].
478 ///
479 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
480 pub fn on_modifiers_changed(
481 &mut self,
482 listener: impl Fn(&ModifiersChangedEvent, &mut Window, &mut App) + 'static,
483 ) {
484 self.modifiers_changed_listeners
485 .push(Box::new(move |event, window, cx| {
486 listener(event, window, cx)
487 }));
488 }
489
490 /// Bind the given callback to drop events of the given type, whether or not the drag started on this element.
491 /// The imperative API equivalent to [`InteractiveElement::on_drop`].
492 ///
493 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
494 pub fn on_drop<T: 'static>(&mut self, listener: impl Fn(&T, &mut Window, &mut App) + 'static) {
495 self.drop_listeners.push((
496 TypeId::of::<T>(),
497 Box::new(move |dragged_value, window, cx| {
498 listener(dragged_value.downcast_ref().unwrap(), window, cx);
499 }),
500 ));
501 }
502
503 /// Use the given predicate to determine whether or not a drop event should be dispatched to this element.
504 /// The imperative API equivalent to [`InteractiveElement::can_drop`].
505 pub fn can_drop(
506 &mut self,
507 predicate: impl Fn(&dyn Any, &mut Window, &mut App) -> bool + 'static,
508 ) {
509 self.can_drop_predicate = Some(Box::new(predicate));
510 }
511
512 /// Bind the given callback to click events of this element.
513 /// The imperative API equivalent to [`StatefulInteractiveElement::on_click`].
514 ///
515 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
516 pub fn on_click(&mut self, listener: impl Fn(&ClickEvent, &mut Window, &mut App) + 'static)
517 where
518 Self: Sized,
519 {
520 self.click_listeners.push(Rc::new(move |event, window, cx| {
521 listener(event, window, cx)
522 }));
523 }
524
525 /// On drag initiation, this callback will be used to create a new view to render the dragged value for a
526 /// drag and drop operation. This API should also be used as the equivalent of 'on drag start' with
527 /// the [`Self::on_drag_move`] API.
528 /// The imperative API equivalent to [`StatefulInteractiveElement::on_drag`].
529 ///
530 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
531 pub fn on_drag<T, W>(
532 &mut self,
533 value: T,
534 constructor: impl Fn(&T, Point<Pixels>, &mut Window, &mut App) -> Entity<W> + 'static,
535 ) where
536 Self: Sized,
537 T: 'static,
538 W: 'static + Render,
539 {
540 debug_assert!(
541 self.drag_listener.is_none(),
542 "calling on_drag more than once on the same element is not supported"
543 );
544 self.drag_listener = Some((
545 Arc::new(value),
546 Box::new(move |value, offset, window, cx| {
547 constructor(value.downcast_ref().unwrap(), offset, window, cx).into()
548 }),
549 ));
550 }
551
552 /// Bind the given callback on the hover start and end events of this element. Note that the boolean
553 /// passed to the callback is true when the hover starts and false when it ends.
554 /// The imperative API equivalent to [`StatefulInteractiveElement::on_hover`].
555 ///
556 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
557 pub fn on_hover(&mut self, listener: impl Fn(&bool, &mut Window, &mut App) + 'static)
558 where
559 Self: Sized,
560 {
561 debug_assert!(
562 self.hover_listener.is_none(),
563 "calling on_hover more than once on the same element is not supported"
564 );
565 self.hover_listener = Some(Box::new(listener));
566 }
567
568 /// Use the given callback to construct a new tooltip view when the mouse hovers over this element.
569 /// The imperative API equivalent to [`StatefulInteractiveElement::tooltip`].
570 pub fn tooltip(&mut self, build_tooltip: impl Fn(&mut Window, &mut App) -> AnyView + 'static)
571 where
572 Self: Sized,
573 {
574 debug_assert!(
575 self.tooltip_builder.is_none(),
576 "calling tooltip more than once on the same element is not supported"
577 );
578 self.tooltip_builder = Some(TooltipBuilder {
579 build: Rc::new(build_tooltip),
580 hoverable: false,
581 });
582 }
583
584 /// Use the given callback to construct a new tooltip view when the mouse hovers over this element.
585 /// The tooltip itself is also hoverable and won't disappear when the user moves the mouse into
586 /// the tooltip. The imperative API equivalent to [`StatefulInteractiveElement::hoverable_tooltip`].
587 pub fn hoverable_tooltip(
588 &mut self,
589 build_tooltip: impl Fn(&mut Window, &mut App) -> AnyView + 'static,
590 ) where
591 Self: Sized,
592 {
593 debug_assert!(
594 self.tooltip_builder.is_none(),
595 "calling tooltip more than once on the same element is not supported"
596 );
597 self.tooltip_builder = Some(TooltipBuilder {
598 build: Rc::new(build_tooltip),
599 hoverable: true,
600 });
601 }
602
603 /// Block the mouse from all interactions with elements behind this element's hitbox. Typically
604 /// `block_mouse_except_scroll` should be preferred.
605 ///
606 /// The imperative API equivalent to [`InteractiveElement::occlude`]
607 pub fn occlude_mouse(&mut self) {
608 self.hitbox_behavior = HitboxBehavior::BlockMouse;
609 }
610
611 /// Set the bounds of this element as a window control area for the platform window.
612 /// The imperative API equivalent to [`InteractiveElement::window_control_area`]
613 pub fn window_control_area(&mut self, area: WindowControlArea) {
614 self.window_control = Some(area);
615 }
616
617 /// Block non-scroll mouse interactions with elements behind this element's hitbox.
618 /// The imperative API equivalent to [`InteractiveElement::block_mouse_except_scroll`].
619 ///
620 /// See [`Hitbox::is_hovered`] for details.
621 pub fn block_mouse_except_scroll(&mut self) {
622 self.hitbox_behavior = HitboxBehavior::BlockMouseExceptScroll;
623 }
624}
625
626/// A trait for elements that want to use the standard GPUI event handlers that don't
627/// require any state.
628pub trait InteractiveElement: Sized {
629 /// Retrieve the interactivity state associated with this element
630 fn interactivity(&mut self) -> &mut Interactivity;
631
632 /// Assign this element to a group of elements that can be styled together
633 fn group(mut self, group: impl Into<SharedString>) -> Self {
634 self.interactivity().group = Some(group.into());
635 self
636 }
637
638 /// Assign this element an ID, so that it can be used with interactivity
639 fn id(mut self, id: impl Into<ElementId>) -> Stateful<Self> {
640 self.interactivity().element_id = Some(id.into());
641
642 Stateful { element: self }
643 }
644
645 /// Track the focus state of the given focus handle on this element.
646 /// If the focus handle is focused by the application, this element will
647 /// apply its focused styles.
648 fn track_focus(mut self, focus_handle: &FocusHandle) -> Self {
649 self.interactivity().focusable = true;
650 self.interactivity().tracked_focus_handle = Some(focus_handle.clone());
651 self
652 }
653
654 /// Set whether this element is a tab stop.
655 ///
656 /// When false, the element remains in tab-index order but cannot be reached via keyboard navigation.
657 /// Useful for container elements: focus the container, then call `window.focus_next()` to focus
658 /// the first tab stop inside it while having the container element itself be unreachable via the keyboard.
659 /// Should only be used with `tab_index`.
660 fn tab_stop(mut self, tab_stop: bool) -> Self {
661 self.interactivity().tab_stop = tab_stop;
662 self
663 }
664
665 /// Set index of the tab stop order, and set this node as a tab stop.
666 /// This will default the element to being a tab stop. See [`Self::tab_stop`] for more information.
667 /// This should only be used in conjunction with `tab_group`
668 /// in order to not interfere with the tab index of other elements.
669 fn tab_index(mut self, index: isize) -> Self {
670 self.interactivity().focusable = true;
671 self.interactivity().tab_index = Some(index);
672 self.interactivity().tab_stop = true;
673 self
674 }
675
676 /// Designate this div as a "tab group". Tab groups have their own location in the tab-index order,
677 /// but for children of the tab group, the tab index is reset to 0. This can be useful for swapping
678 /// the order of tab stops within the group, without having to renumber all the tab stops in the whole
679 /// application.
680 fn tab_group(mut self) -> Self {
681 self.interactivity().tab_group = true;
682 if self.interactivity().tab_index.is_none() {
683 self.interactivity().tab_index = Some(0);
684 }
685 self
686 }
687
688 /// Set the keymap context for this element. This will be used to determine
689 /// which action to dispatch from the keymap.
690 fn key_context<C, E>(mut self, key_context: C) -> Self
691 where
692 C: TryInto<KeyContext, Error = E>,
693 E: Debug,
694 {
695 if let Some(key_context) = key_context.try_into().log_err() {
696 self.interactivity().key_context = Some(key_context);
697 }
698 self
699 }
700
701 /// Apply the given style to this element when the mouse hovers over it
702 fn hover(mut self, f: impl FnOnce(StyleRefinement) -> StyleRefinement) -> Self {
703 debug_assert!(
704 self.interactivity().hover_style.is_none(),
705 "hover style already set"
706 );
707 self.interactivity().hover_style = Some(Box::new(f(StyleRefinement::default())));
708 self
709 }
710
711 /// Apply the given style to this element when the mouse hovers over a group member
712 fn group_hover(
713 mut self,
714 group_name: impl Into<SharedString>,
715 f: impl FnOnce(StyleRefinement) -> StyleRefinement,
716 ) -> Self {
717 self.interactivity().group_hover_style = Some(GroupStyle {
718 group: group_name.into(),
719 style: Box::new(f(StyleRefinement::default())),
720 });
721 self
722 }
723
724 /// Bind the given callback to the mouse down event for the given mouse button.
725 /// The fluent API equivalent to [`Interactivity::on_mouse_down`].
726 ///
727 /// See [`Context::listener`](crate::Context::listener) to get access to the view state from this callback.
728 fn on_mouse_down(
729 mut self,
730 button: MouseButton,
731 listener: impl Fn(&MouseDownEvent, &mut Window, &mut App) + 'static,
732 ) -> Self {
733 self.interactivity().on_mouse_down(button, listener);
734 self
735 }
736
737 #[cfg(any(test, feature = "test-support"))]
738 /// Set a key that can be used to look up this element's bounds
739 /// in the [`crate::VisualTestContext::debug_bounds`] map
740 /// This is a noop in release builds
741 fn debug_selector(mut self, f: impl FnOnce() -> String) -> Self {
742 self.interactivity().debug_selector = Some(f());
743 self
744 }
745
746 #[cfg(not(any(test, feature = "test-support")))]
747 /// Set a key that can be used to look up this element's bounds
748 /// in the [`crate::VisualTestContext::debug_bounds`] map
749 /// This is a noop in release builds
750 #[inline]
751 fn debug_selector(self, _: impl FnOnce() -> String) -> Self {
752 self
753 }
754
755 /// Bind the given callback to the mouse down event for any button, during the capture phase.
756 /// The fluent API equivalent to [`Interactivity::capture_any_mouse_down`].
757 ///
758 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
759 fn capture_any_mouse_down(
760 mut self,
761 listener: impl Fn(&MouseDownEvent, &mut Window, &mut App) + 'static,
762 ) -> Self {
763 self.interactivity().capture_any_mouse_down(listener);
764 self
765 }
766
767 /// Bind the given callback to the mouse down event for any button, during the capture phase.
768 /// The fluent API equivalent to [`Interactivity::on_any_mouse_down`].
769 ///
770 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
771 fn on_any_mouse_down(
772 mut self,
773 listener: impl Fn(&MouseDownEvent, &mut Window, &mut App) + 'static,
774 ) -> Self {
775 self.interactivity().on_any_mouse_down(listener);
776 self
777 }
778
779 /// Bind the given callback to the mouse up event for the given button, during the bubble phase.
780 /// The fluent API equivalent to [`Interactivity::on_mouse_up`].
781 ///
782 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
783 fn on_mouse_up(
784 mut self,
785 button: MouseButton,
786 listener: impl Fn(&MouseUpEvent, &mut Window, &mut App) + 'static,
787 ) -> Self {
788 self.interactivity().on_mouse_up(button, listener);
789 self
790 }
791
792 /// Bind the given callback to the mouse up event for any button, during the capture phase.
793 /// The fluent API equivalent to [`Interactivity::capture_any_mouse_up`].
794 ///
795 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
796 fn capture_any_mouse_up(
797 mut self,
798 listener: impl Fn(&MouseUpEvent, &mut Window, &mut App) + 'static,
799 ) -> Self {
800 self.interactivity().capture_any_mouse_up(listener);
801 self
802 }
803
804 /// Bind the given callback to the mouse pressure event, during the bubble phase
805 /// the fluent API equivalent to [`Interactivity::on_mouse_pressure`]
806 ///
807 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
808 fn on_mouse_pressure(
809 mut self,
810 listener: impl Fn(&MousePressureEvent, &mut Window, &mut App) + 'static,
811 ) -> Self {
812 self.interactivity().on_mouse_pressure(listener);
813 self
814 }
815
816 /// Bind the given callback to the mouse pressure event, during the capture phase
817 /// the fluent API equivalent to [`Interactivity::on_mouse_pressure`]
818 ///
819 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
820 fn capture_mouse_pressure(
821 mut self,
822 listener: impl Fn(&MousePressureEvent, &mut Window, &mut App) + 'static,
823 ) -> Self {
824 self.interactivity().capture_mouse_pressure(listener);
825 self
826 }
827
828 /// Bind the given callback to the mouse down event, on any button, during the capture phase,
829 /// when the mouse is outside of the bounds of this element.
830 /// The fluent API equivalent to [`Interactivity::on_mouse_down_out`].
831 ///
832 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
833 fn on_mouse_down_out(
834 mut self,
835 listener: impl Fn(&MouseDownEvent, &mut Window, &mut App) + 'static,
836 ) -> Self {
837 self.interactivity().on_mouse_down_out(listener);
838 self
839 }
840
841 /// Bind the given callback to the mouse up event, for the given button, during the capture phase,
842 /// when the mouse is outside of the bounds of this element.
843 /// The fluent API equivalent to [`Interactivity::on_mouse_up_out`].
844 ///
845 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
846 fn on_mouse_up_out(
847 mut self,
848 button: MouseButton,
849 listener: impl Fn(&MouseUpEvent, &mut Window, &mut App) + 'static,
850 ) -> Self {
851 self.interactivity().on_mouse_up_out(button, listener);
852 self
853 }
854
855 /// Bind the given callback to the mouse move event, during the bubble phase.
856 /// The fluent API equivalent to [`Interactivity::on_mouse_move`].
857 ///
858 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
859 fn on_mouse_move(
860 mut self,
861 listener: impl Fn(&MouseMoveEvent, &mut Window, &mut App) + 'static,
862 ) -> Self {
863 self.interactivity().on_mouse_move(listener);
864 self
865 }
866
867 /// Bind the given callback to the mouse drag event of the given type. Note that this
868 /// will be called for all move events, inside or outside of this element, as long as the
869 /// drag was started with this element under the mouse. Useful for implementing draggable
870 /// UIs that don't conform to a drag and drop style interaction, like resizing.
871 /// The fluent API equivalent to [`Interactivity::on_drag_move`].
872 ///
873 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
874 fn on_drag_move<T: 'static>(
875 mut self,
876 listener: impl Fn(&DragMoveEvent<T>, &mut Window, &mut App) + 'static,
877 ) -> Self {
878 self.interactivity().on_drag_move(listener);
879 self
880 }
881
882 /// Bind the given callback to scroll wheel events during the bubble phase.
883 /// The fluent API equivalent to [`Interactivity::on_scroll_wheel`].
884 ///
885 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
886 fn on_scroll_wheel(
887 mut self,
888 listener: impl Fn(&ScrollWheelEvent, &mut Window, &mut App) + 'static,
889 ) -> Self {
890 self.interactivity().on_scroll_wheel(listener);
891 self
892 }
893
894 /// Capture the given action, before normal action dispatch can fire.
895 /// The fluent API equivalent to [`Interactivity::capture_action`].
896 ///
897 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
898 fn capture_action<A: Action>(
899 mut self,
900 listener: impl Fn(&A, &mut Window, &mut App) + 'static,
901 ) -> Self {
902 self.interactivity().capture_action(listener);
903 self
904 }
905
906 /// Bind the given callback to an action dispatch during the bubble phase.
907 /// The fluent API equivalent to [`Interactivity::on_action`].
908 ///
909 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
910 fn on_action<A: Action>(
911 mut self,
912 listener: impl Fn(&A, &mut Window, &mut App) + 'static,
913 ) -> Self {
914 self.interactivity().on_action(listener);
915 self
916 }
917
918 /// Bind the given callback to an action dispatch, based on a dynamic action parameter
919 /// instead of a type parameter. Useful for component libraries that want to expose
920 /// action bindings to their users.
921 /// The fluent API equivalent to [`Interactivity::on_boxed_action`].
922 ///
923 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
924 fn on_boxed_action(
925 mut self,
926 action: &dyn Action,
927 listener: impl Fn(&dyn Action, &mut Window, &mut App) + 'static,
928 ) -> Self {
929 self.interactivity().on_boxed_action(action, listener);
930 self
931 }
932
933 /// Bind the given callback to key down events during the bubble phase.
934 /// The fluent API equivalent to [`Interactivity::on_key_down`].
935 ///
936 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
937 fn on_key_down(
938 mut self,
939 listener: impl Fn(&KeyDownEvent, &mut Window, &mut App) + 'static,
940 ) -> Self {
941 self.interactivity().on_key_down(listener);
942 self
943 }
944
945 /// Bind the given callback to key down events during the capture phase.
946 /// The fluent API equivalent to [`Interactivity::capture_key_down`].
947 ///
948 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
949 fn capture_key_down(
950 mut self,
951 listener: impl Fn(&KeyDownEvent, &mut Window, &mut App) + 'static,
952 ) -> Self {
953 self.interactivity().capture_key_down(listener);
954 self
955 }
956
957 /// Bind the given callback to key up events during the bubble phase.
958 /// The fluent API equivalent to [`Interactivity::on_key_up`].
959 ///
960 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
961 fn on_key_up(
962 mut self,
963 listener: impl Fn(&KeyUpEvent, &mut Window, &mut App) + 'static,
964 ) -> Self {
965 self.interactivity().on_key_up(listener);
966 self
967 }
968
969 /// Bind the given callback to key up events during the capture phase.
970 /// The fluent API equivalent to [`Interactivity::capture_key_up`].
971 ///
972 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
973 fn capture_key_up(
974 mut self,
975 listener: impl Fn(&KeyUpEvent, &mut Window, &mut App) + 'static,
976 ) -> Self {
977 self.interactivity().capture_key_up(listener);
978 self
979 }
980
981 /// Bind the given callback to modifiers changing events.
982 /// The fluent API equivalent to [`Interactivity::on_modifiers_changed`].
983 ///
984 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
985 fn on_modifiers_changed(
986 mut self,
987 listener: impl Fn(&ModifiersChangedEvent, &mut Window, &mut App) + 'static,
988 ) -> Self {
989 self.interactivity().on_modifiers_changed(listener);
990 self
991 }
992
993 /// Apply the given style when the given data type is dragged over this element
994 fn drag_over<S: 'static>(
995 mut self,
996 f: impl 'static + Fn(StyleRefinement, &S, &mut Window, &mut App) -> StyleRefinement,
997 ) -> Self {
998 self.interactivity().drag_over_styles.push((
999 TypeId::of::<S>(),
1000 Box::new(move |currently_dragged: &dyn Any, window, cx| {
1001 f(
1002 StyleRefinement::default(),
1003 currently_dragged.downcast_ref::<S>().unwrap(),
1004 window,
1005 cx,
1006 )
1007 }),
1008 ));
1009 self
1010 }
1011
1012 /// Apply the given style when the given data type is dragged over this element's group
1013 fn group_drag_over<S: 'static>(
1014 mut self,
1015 group_name: impl Into<SharedString>,
1016 f: impl FnOnce(StyleRefinement) -> StyleRefinement,
1017 ) -> Self {
1018 self.interactivity().group_drag_over_styles.push((
1019 TypeId::of::<S>(),
1020 GroupStyle {
1021 group: group_name.into(),
1022 style: Box::new(f(StyleRefinement::default())),
1023 },
1024 ));
1025 self
1026 }
1027
1028 /// Bind the given callback to drop events of the given type, whether or not the drag started on this element.
1029 /// The fluent API equivalent to [`Interactivity::on_drop`].
1030 ///
1031 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
1032 fn on_drop<T: 'static>(
1033 mut self,
1034 listener: impl Fn(&T, &mut Window, &mut App) + 'static,
1035 ) -> Self {
1036 self.interactivity().on_drop(listener);
1037 self
1038 }
1039
1040 /// Use the given predicate to determine whether or not a drop event should be dispatched to this element.
1041 /// The fluent API equivalent to [`Interactivity::can_drop`].
1042 fn can_drop(
1043 mut self,
1044 predicate: impl Fn(&dyn Any, &mut Window, &mut App) -> bool + 'static,
1045 ) -> Self {
1046 self.interactivity().can_drop(predicate);
1047 self
1048 }
1049
1050 /// Block the mouse from all interactions with elements behind this element's hitbox. Typically
1051 /// `block_mouse_except_scroll` should be preferred.
1052 /// The fluent API equivalent to [`Interactivity::occlude_mouse`].
1053 fn occlude(mut self) -> Self {
1054 self.interactivity().occlude_mouse();
1055 self
1056 }
1057
1058 /// Set the bounds of this element as a window control area for the platform window.
1059 /// The fluent API equivalent to [`Interactivity::window_control_area`].
1060 fn window_control_area(mut self, area: WindowControlArea) -> Self {
1061 self.interactivity().window_control_area(area);
1062 self
1063 }
1064
1065 /// Block non-scroll mouse interactions with elements behind this element's hitbox.
1066 /// The fluent API equivalent to [`Interactivity::block_mouse_except_scroll`].
1067 ///
1068 /// See [`Hitbox::is_hovered`] for details.
1069 fn block_mouse_except_scroll(mut self) -> Self {
1070 self.interactivity().block_mouse_except_scroll();
1071 self
1072 }
1073
1074 /// Set the given styles to be applied when this element, specifically, is focused.
1075 /// Requires that the element is focusable. Elements can be made focusable using [`InteractiveElement::track_focus`].
1076 fn focus(mut self, f: impl FnOnce(StyleRefinement) -> StyleRefinement) -> Self
1077 where
1078 Self: Sized,
1079 {
1080 self.interactivity().focus_style = Some(Box::new(f(StyleRefinement::default())));
1081 self
1082 }
1083
1084 /// Set the given styles to be applied when this element is inside another element that is focused.
1085 /// Requires that the element is focusable. Elements can be made focusable using [`InteractiveElement::track_focus`].
1086 fn in_focus(mut self, f: impl FnOnce(StyleRefinement) -> StyleRefinement) -> Self
1087 where
1088 Self: Sized,
1089 {
1090 self.interactivity().in_focus_style = Some(Box::new(f(StyleRefinement::default())));
1091 self
1092 }
1093
1094 /// Set the given styles to be applied when this element is focused via keyboard navigation.
1095 /// This is similar to CSS's `:focus-visible` pseudo-class - it only applies when the element
1096 /// is focused AND the user is navigating via keyboard (not mouse clicks).
1097 /// Requires that the element is focusable. Elements can be made focusable using [`InteractiveElement::track_focus`].
1098 fn focus_visible(mut self, f: impl FnOnce(StyleRefinement) -> StyleRefinement) -> Self
1099 where
1100 Self: Sized,
1101 {
1102 self.interactivity().focus_visible_style = Some(Box::new(f(StyleRefinement::default())));
1103 self
1104 }
1105}
1106
1107/// A trait for elements that want to use the standard GPUI interactivity features
1108/// that require state.
1109pub trait StatefulInteractiveElement: InteractiveElement {
1110 /// Set this element to focusable.
1111 fn focusable(mut self) -> Self {
1112 self.interactivity().focusable = true;
1113 self
1114 }
1115
1116 /// Set the overflow x and y to scroll.
1117 fn overflow_scroll(mut self) -> Self {
1118 self.interactivity().base_style.overflow.x = Some(Overflow::Scroll);
1119 self.interactivity().base_style.overflow.y = Some(Overflow::Scroll);
1120 self
1121 }
1122
1123 /// Set the overflow x to scroll.
1124 fn overflow_x_scroll(mut self) -> Self {
1125 self.interactivity().base_style.overflow.x = Some(Overflow::Scroll);
1126 self
1127 }
1128
1129 /// Set the overflow y to scroll.
1130 fn overflow_y_scroll(mut self) -> Self {
1131 self.interactivity().base_style.overflow.y = Some(Overflow::Scroll);
1132 self
1133 }
1134
1135 /// Set the space to be reserved for rendering the scrollbar.
1136 ///
1137 /// This will only affect the layout of the element when overflow for this element is set to
1138 /// `Overflow::Scroll`.
1139 fn scrollbar_width(mut self, width: impl Into<AbsoluteLength>) -> Self {
1140 self.interactivity().base_style.scrollbar_width = Some(width.into());
1141 self
1142 }
1143
1144 /// Track the scroll state of this element with the given handle.
1145 fn track_scroll(mut self, scroll_handle: &ScrollHandle) -> Self {
1146 self.interactivity().tracked_scroll_handle = Some(scroll_handle.clone());
1147 self
1148 }
1149
1150 /// Track the scroll state of this element with the given handle.
1151 fn anchor_scroll(mut self, scroll_anchor: Option<ScrollAnchor>) -> Self {
1152 self.interactivity().scroll_anchor = scroll_anchor;
1153 self
1154 }
1155
1156 /// Set the given styles to be applied when this element is active.
1157 fn active(mut self, f: impl FnOnce(StyleRefinement) -> StyleRefinement) -> Self
1158 where
1159 Self: Sized,
1160 {
1161 self.interactivity().active_style = Some(Box::new(f(StyleRefinement::default())));
1162 self
1163 }
1164
1165 /// Set the given styles to be applied when this element's group is active.
1166 fn group_active(
1167 mut self,
1168 group_name: impl Into<SharedString>,
1169 f: impl FnOnce(StyleRefinement) -> StyleRefinement,
1170 ) -> Self
1171 where
1172 Self: Sized,
1173 {
1174 self.interactivity().group_active_style = Some(GroupStyle {
1175 group: group_name.into(),
1176 style: Box::new(f(StyleRefinement::default())),
1177 });
1178 self
1179 }
1180
1181 /// Bind the given callback to click events of this element.
1182 /// The fluent API equivalent to [`Interactivity::on_click`].
1183 ///
1184 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
1185 fn on_click(mut self, listener: impl Fn(&ClickEvent, &mut Window, &mut App) + 'static) -> Self
1186 where
1187 Self: Sized,
1188 {
1189 self.interactivity().on_click(listener);
1190 self
1191 }
1192
1193 /// On drag initiation, this callback will be used to create a new view to render the dragged value for a
1194 /// drag and drop operation. This API should also be used as the equivalent of 'on drag start' with
1195 /// the [`InteractiveElement::on_drag_move`] API.
1196 /// The callback also has access to the offset of triggering click from the origin of parent element.
1197 /// The fluent API equivalent to [`Interactivity::on_drag`].
1198 ///
1199 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
1200 fn on_drag<T, W>(
1201 mut self,
1202 value: T,
1203 constructor: impl Fn(&T, Point<Pixels>, &mut Window, &mut App) -> Entity<W> + 'static,
1204 ) -> Self
1205 where
1206 Self: Sized,
1207 T: 'static,
1208 W: 'static + Render,
1209 {
1210 self.interactivity().on_drag(value, constructor);
1211 self
1212 }
1213
1214 /// Bind the given callback on the hover start and end events of this element. Note that the boolean
1215 /// passed to the callback is true when the hover starts and false when it ends.
1216 /// The fluent API equivalent to [`Interactivity::on_hover`].
1217 ///
1218 /// See [`Context::listener`](crate::Context::listener) to get access to a view's state from this callback.
1219 fn on_hover(mut self, listener: impl Fn(&bool, &mut Window, &mut App) + 'static) -> Self
1220 where
1221 Self: Sized,
1222 {
1223 self.interactivity().on_hover(listener);
1224 self
1225 }
1226
1227 /// Use the given callback to construct a new tooltip view when the mouse hovers over this element.
1228 /// The fluent API equivalent to [`Interactivity::tooltip`].
1229 fn tooltip(mut self, build_tooltip: impl Fn(&mut Window, &mut App) -> AnyView + 'static) -> Self
1230 where
1231 Self: Sized,
1232 {
1233 self.interactivity().tooltip(build_tooltip);
1234 self
1235 }
1236
1237 /// Use the given callback to construct a new tooltip view when the mouse hovers over this element.
1238 /// The tooltip itself is also hoverable and won't disappear when the user moves the mouse into
1239 /// the tooltip. The fluent API equivalent to [`Interactivity::hoverable_tooltip`].
1240 fn hoverable_tooltip(
1241 mut self,
1242 build_tooltip: impl Fn(&mut Window, &mut App) -> AnyView + 'static,
1243 ) -> Self
1244 where
1245 Self: Sized,
1246 {
1247 self.interactivity().hoverable_tooltip(build_tooltip);
1248 self
1249 }
1250}
1251
1252pub(crate) type MouseDownListener =
1253 Box<dyn Fn(&MouseDownEvent, DispatchPhase, &Hitbox, &mut Window, &mut App) + 'static>;
1254pub(crate) type MouseUpListener =
1255 Box<dyn Fn(&MouseUpEvent, DispatchPhase, &Hitbox, &mut Window, &mut App) + 'static>;
1256pub(crate) type MousePressureListener =
1257 Box<dyn Fn(&MousePressureEvent, DispatchPhase, &Hitbox, &mut Window, &mut App) + 'static>;
1258pub(crate) type MouseMoveListener =
1259 Box<dyn Fn(&MouseMoveEvent, DispatchPhase, &Hitbox, &mut Window, &mut App) + 'static>;
1260
1261pub(crate) type ScrollWheelListener =
1262 Box<dyn Fn(&ScrollWheelEvent, DispatchPhase, &Hitbox, &mut Window, &mut App) + 'static>;
1263
1264pub(crate) type ClickListener = Rc<dyn Fn(&ClickEvent, &mut Window, &mut App) + 'static>;
1265
1266pub(crate) type DragListener =
1267 Box<dyn Fn(&dyn Any, Point<Pixels>, &mut Window, &mut App) -> AnyView + 'static>;
1268
1269type DropListener = Box<dyn Fn(&dyn Any, &mut Window, &mut App) + 'static>;
1270
1271type CanDropPredicate = Box<dyn Fn(&dyn Any, &mut Window, &mut App) -> bool + 'static>;
1272
1273pub(crate) struct TooltipBuilder {
1274 build: Rc<dyn Fn(&mut Window, &mut App) -> AnyView + 'static>,
1275 hoverable: bool,
1276}
1277
1278pub(crate) type KeyDownListener =
1279 Box<dyn Fn(&KeyDownEvent, DispatchPhase, &mut Window, &mut App) + 'static>;
1280
1281pub(crate) type KeyUpListener =
1282 Box<dyn Fn(&KeyUpEvent, DispatchPhase, &mut Window, &mut App) + 'static>;
1283
1284pub(crate) type ModifiersChangedListener =
1285 Box<dyn Fn(&ModifiersChangedEvent, &mut Window, &mut App) + 'static>;
1286
1287pub(crate) type ActionListener =
1288 Box<dyn Fn(&dyn Any, DispatchPhase, &mut Window, &mut App) + 'static>;
1289
1290/// Construct a new [`Div`] element
1291#[track_caller]
1292pub fn div() -> Div {
1293 Div {
1294 interactivity: Interactivity::new(),
1295 children: SmallVec::default(),
1296 prepaint_listener: None,
1297 image_cache: None,
1298 }
1299}
1300
1301/// A [`Div`] element, the all-in-one element for building complex UIs in GPUI
1302pub struct Div {
1303 interactivity: Interactivity,
1304 children: SmallVec<[StackSafe<AnyElement>; 2]>,
1305 prepaint_listener: Option<Box<dyn Fn(Vec<Bounds<Pixels>>, &mut Window, &mut App) + 'static>>,
1306 image_cache: Option<Box<dyn ImageCacheProvider>>,
1307}
1308
1309impl Div {
1310 /// Add a listener to be called when the children of this `Div` are prepainted.
1311 /// This allows you to store the [`Bounds`] of the children for later use.
1312 pub fn on_children_prepainted(
1313 mut self,
1314 listener: impl Fn(Vec<Bounds<Pixels>>, &mut Window, &mut App) + 'static,
1315 ) -> Self {
1316 self.prepaint_listener = Some(Box::new(listener));
1317 self
1318 }
1319
1320 /// Add an image cache at the location of this div in the element tree.
1321 pub fn image_cache(mut self, cache: impl ImageCacheProvider) -> Self {
1322 self.image_cache = Some(Box::new(cache));
1323 self
1324 }
1325}
1326
1327/// A frame state for a `Div` element, which contains layout IDs for its children.
1328///
1329/// This struct is used internally by the `Div` element to manage the layout state of its children
1330/// during the UI update cycle. It holds a small vector of `LayoutId` values, each corresponding to
1331/// a child element of the `Div`. These IDs are used to query the layout engine for the computed
1332/// bounds of the children after the layout phase is complete.
1333pub struct DivFrameState {
1334 child_layout_ids: SmallVec<[LayoutId; 2]>,
1335}
1336
1337/// Interactivity state displayed an manipulated in the inspector.
1338#[derive(Clone)]
1339pub struct DivInspectorState {
1340 /// The inspected element's base style. This is used for both inspecting and modifying the
1341 /// state. In the future it will make sense to separate the read and write, possibly tracking
1342 /// the modifications.
1343 #[cfg(any(feature = "inspector", debug_assertions))]
1344 pub base_style: Box<StyleRefinement>,
1345 /// Inspects the bounds of the element.
1346 pub bounds: Bounds<Pixels>,
1347 /// Size of the children of the element, or `bounds.size` if it has no children.
1348 pub content_size: Size<Pixels>,
1349}
1350
1351impl Styled for Div {
1352 fn style(&mut self) -> &mut StyleRefinement {
1353 &mut self.interactivity.base_style
1354 }
1355}
1356
1357impl InteractiveElement for Div {
1358 fn interactivity(&mut self) -> &mut Interactivity {
1359 &mut self.interactivity
1360 }
1361}
1362
1363impl ParentElement for Div {
1364 fn extend(&mut self, elements: impl IntoIterator<Item = AnyElement>) {
1365 self.children
1366 .extend(elements.into_iter().map(StackSafe::new))
1367 }
1368}
1369
1370impl Element for Div {
1371 type RequestLayoutState = DivFrameState;
1372 type PrepaintState = Option<Hitbox>;
1373
1374 fn id(&self) -> Option<ElementId> {
1375 self.interactivity.element_id.clone()
1376 }
1377
1378 fn source_location(&self) -> Option<&'static std::panic::Location<'static>> {
1379 self.interactivity.source_location()
1380 }
1381
1382 #[stacksafe]
1383 fn request_layout(
1384 &mut self,
1385 global_id: Option<&GlobalElementId>,
1386 inspector_id: Option<&InspectorElementId>,
1387 window: &mut Window,
1388 cx: &mut App,
1389 ) -> (LayoutId, Self::RequestLayoutState) {
1390 let mut child_layout_ids = SmallVec::new();
1391 let image_cache = self
1392 .image_cache
1393 .as_mut()
1394 .map(|provider| provider.provide(window, cx));
1395
1396 let layout_id = window.with_image_cache(image_cache, |window| {
1397 self.interactivity.request_layout(
1398 global_id,
1399 inspector_id,
1400 window,
1401 cx,
1402 |style, window, cx| {
1403 window.with_text_style(style.text_style().cloned(), |window| {
1404 child_layout_ids = self
1405 .children
1406 .iter_mut()
1407 .map(|child| child.request_layout(window, cx))
1408 .collect::<SmallVec<_>>();
1409 window.request_layout(style, child_layout_ids.iter().copied(), cx)
1410 })
1411 },
1412 )
1413 });
1414
1415 (layout_id, DivFrameState { child_layout_ids })
1416 }
1417
1418 #[stacksafe]
1419 fn prepaint(
1420 &mut self,
1421 global_id: Option<&GlobalElementId>,
1422 inspector_id: Option<&InspectorElementId>,
1423 bounds: Bounds<Pixels>,
1424 request_layout: &mut Self::RequestLayoutState,
1425 window: &mut Window,
1426 cx: &mut App,
1427 ) -> Option<Hitbox> {
1428 let has_prepaint_listener = self.prepaint_listener.is_some();
1429 let mut children_bounds = Vec::with_capacity(if has_prepaint_listener {
1430 request_layout.child_layout_ids.len()
1431 } else {
1432 0
1433 });
1434
1435 let mut child_min = point(Pixels::MAX, Pixels::MAX);
1436 let mut child_max = Point::default();
1437 if let Some(handle) = self.interactivity.scroll_anchor.as_ref() {
1438 *handle.last_origin.borrow_mut() = bounds.origin - window.element_offset();
1439 }
1440 let content_size = if request_layout.child_layout_ids.is_empty() {
1441 bounds.size
1442 } else if let Some(scroll_handle) = self.interactivity.tracked_scroll_handle.as_ref() {
1443 let mut state = scroll_handle.0.borrow_mut();
1444 state.child_bounds = Vec::with_capacity(request_layout.child_layout_ids.len());
1445 for child_layout_id in &request_layout.child_layout_ids {
1446 let child_bounds = window.layout_bounds(*child_layout_id);
1447 child_min = child_min.min(&child_bounds.origin);
1448 child_max = child_max.max(&child_bounds.bottom_right());
1449 state.child_bounds.push(child_bounds);
1450 }
1451 (child_max - child_min).into()
1452 } else {
1453 for child_layout_id in &request_layout.child_layout_ids {
1454 let child_bounds = window.layout_bounds(*child_layout_id);
1455 child_min = child_min.min(&child_bounds.origin);
1456 child_max = child_max.max(&child_bounds.bottom_right());
1457
1458 if has_prepaint_listener {
1459 children_bounds.push(child_bounds);
1460 }
1461 }
1462 (child_max - child_min).into()
1463 };
1464
1465 if let Some(scroll_handle) = self.interactivity.tracked_scroll_handle.as_ref() {
1466 scroll_handle.scroll_to_active_item();
1467 }
1468
1469 self.interactivity.prepaint(
1470 global_id,
1471 inspector_id,
1472 bounds,
1473 content_size,
1474 window,
1475 cx,
1476 |style, scroll_offset, hitbox, window, cx| {
1477 // skip children
1478 if style.display == Display::None {
1479 return hitbox;
1480 }
1481
1482 window.with_element_offset(scroll_offset, |window| {
1483 for child in &mut self.children {
1484 child.prepaint(window, cx);
1485 }
1486 });
1487
1488 if let Some(listener) = self.prepaint_listener.as_ref() {
1489 listener(children_bounds, window, cx);
1490 }
1491
1492 hitbox
1493 },
1494 )
1495 }
1496
1497 #[stacksafe]
1498 fn paint(
1499 &mut self,
1500 global_id: Option<&GlobalElementId>,
1501 inspector_id: Option<&InspectorElementId>,
1502 bounds: Bounds<Pixels>,
1503 _request_layout: &mut Self::RequestLayoutState,
1504 hitbox: &mut Option<Hitbox>,
1505 window: &mut Window,
1506 cx: &mut App,
1507 ) {
1508 let image_cache = self
1509 .image_cache
1510 .as_mut()
1511 .map(|provider| provider.provide(window, cx));
1512
1513 window.with_image_cache(image_cache, |window| {
1514 self.interactivity.paint(
1515 global_id,
1516 inspector_id,
1517 bounds,
1518 hitbox.as_ref(),
1519 window,
1520 cx,
1521 |style, window, cx| {
1522 // skip children
1523 if style.display == Display::None {
1524 return;
1525 }
1526
1527 for child in &mut self.children {
1528 child.paint(window, cx);
1529 }
1530 },
1531 )
1532 });
1533 }
1534}
1535
1536impl IntoElement for Div {
1537 type Element = Self;
1538
1539 fn into_element(self) -> Self::Element {
1540 self
1541 }
1542}
1543
1544/// The interactivity struct. Powers all of the general-purpose
1545/// interactivity in the `Div` element.
1546#[derive(Default)]
1547pub struct Interactivity {
1548 /// The element ID of the element. In id is required to support a stateful subset of the interactivity such as on_click.
1549 pub element_id: Option<ElementId>,
1550 /// Whether the element was clicked. This will only be present after layout.
1551 pub active: Option<bool>,
1552 /// Whether the element was hovered. This will only be present after paint if an hitbox
1553 /// was created for the interactive element.
1554 pub hovered: Option<bool>,
1555 pub(crate) tooltip_id: Option<TooltipId>,
1556 pub(crate) content_size: Size<Pixels>,
1557 pub(crate) key_context: Option<KeyContext>,
1558 pub(crate) focusable: bool,
1559 pub(crate) tracked_focus_handle: Option<FocusHandle>,
1560 pub(crate) tracked_scroll_handle: Option<ScrollHandle>,
1561 pub(crate) scroll_anchor: Option<ScrollAnchor>,
1562 pub(crate) scroll_offset: Option<Rc<RefCell<Point<Pixels>>>>,
1563 pub(crate) group: Option<SharedString>,
1564 /// The base style of the element, before any modifications are applied
1565 /// by focus, active, etc.
1566 pub base_style: Box<StyleRefinement>,
1567 pub(crate) focus_style: Option<Box<StyleRefinement>>,
1568 pub(crate) in_focus_style: Option<Box<StyleRefinement>>,
1569 pub(crate) focus_visible_style: Option<Box<StyleRefinement>>,
1570 pub(crate) hover_style: Option<Box<StyleRefinement>>,
1571 pub(crate) group_hover_style: Option<GroupStyle>,
1572 pub(crate) active_style: Option<Box<StyleRefinement>>,
1573 pub(crate) group_active_style: Option<GroupStyle>,
1574 pub(crate) drag_over_styles: Vec<(
1575 TypeId,
1576 Box<dyn Fn(&dyn Any, &mut Window, &mut App) -> StyleRefinement>,
1577 )>,
1578 pub(crate) group_drag_over_styles: Vec<(TypeId, GroupStyle)>,
1579 pub(crate) mouse_down_listeners: Vec<MouseDownListener>,
1580 pub(crate) mouse_up_listeners: Vec<MouseUpListener>,
1581 pub(crate) mouse_pressure_listeners: Vec<MousePressureListener>,
1582 pub(crate) mouse_move_listeners: Vec<MouseMoveListener>,
1583 pub(crate) scroll_wheel_listeners: Vec<ScrollWheelListener>,
1584 pub(crate) key_down_listeners: Vec<KeyDownListener>,
1585 pub(crate) key_up_listeners: Vec<KeyUpListener>,
1586 pub(crate) modifiers_changed_listeners: Vec<ModifiersChangedListener>,
1587 pub(crate) action_listeners: Vec<(TypeId, ActionListener)>,
1588 pub(crate) drop_listeners: Vec<(TypeId, DropListener)>,
1589 pub(crate) can_drop_predicate: Option<CanDropPredicate>,
1590 pub(crate) click_listeners: Vec<ClickListener>,
1591 pub(crate) drag_listener: Option<(Arc<dyn Any>, DragListener)>,
1592 pub(crate) hover_listener: Option<Box<dyn Fn(&bool, &mut Window, &mut App)>>,
1593 pub(crate) tooltip_builder: Option<TooltipBuilder>,
1594 pub(crate) window_control: Option<WindowControlArea>,
1595 pub(crate) hitbox_behavior: HitboxBehavior,
1596 pub(crate) tab_index: Option<isize>,
1597 pub(crate) tab_group: bool,
1598 pub(crate) tab_stop: bool,
1599
1600 #[cfg(any(feature = "inspector", debug_assertions))]
1601 pub(crate) source_location: Option<&'static core::panic::Location<'static>>,
1602
1603 #[cfg(any(test, feature = "test-support"))]
1604 pub(crate) debug_selector: Option<String>,
1605}
1606
1607impl Interactivity {
1608 /// Layout this element according to this interactivity state's configured styles
1609 pub fn request_layout(
1610 &mut self,
1611 global_id: Option<&GlobalElementId>,
1612 _inspector_id: Option<&InspectorElementId>,
1613 window: &mut Window,
1614 cx: &mut App,
1615 f: impl FnOnce(Style, &mut Window, &mut App) -> LayoutId,
1616 ) -> LayoutId {
1617 #[cfg(any(feature = "inspector", debug_assertions))]
1618 window.with_inspector_state(
1619 _inspector_id,
1620 cx,
1621 |inspector_state: &mut Option<DivInspectorState>, _window| {
1622 if let Some(inspector_state) = inspector_state {
1623 self.base_style = inspector_state.base_style.clone();
1624 } else {
1625 *inspector_state = Some(DivInspectorState {
1626 base_style: self.base_style.clone(),
1627 bounds: Default::default(),
1628 content_size: Default::default(),
1629 })
1630 }
1631 },
1632 );
1633
1634 window.with_optional_element_state::<InteractiveElementState, _>(
1635 global_id,
1636 |element_state, window| {
1637 let mut element_state =
1638 element_state.map(|element_state| element_state.unwrap_or_default());
1639
1640 if let Some(element_state) = element_state.as_ref()
1641 && cx.has_active_drag()
1642 {
1643 if let Some(pending_mouse_down) = element_state.pending_mouse_down.as_ref() {
1644 *pending_mouse_down.borrow_mut() = None;
1645 }
1646 if let Some(clicked_state) = element_state.clicked_state.as_ref() {
1647 *clicked_state.borrow_mut() = ElementClickedState::default();
1648 }
1649 }
1650
1651 // Ensure we store a focus handle in our element state if we're focusable.
1652 // If there's an explicit focus handle we're tracking, use that. Otherwise
1653 // create a new handle and store it in the element state, which lives for as
1654 // as frames contain an element with this id.
1655 if self.focusable
1656 && self.tracked_focus_handle.is_none()
1657 && let Some(element_state) = element_state.as_mut()
1658 {
1659 let mut handle = element_state
1660 .focus_handle
1661 .get_or_insert_with(|| cx.focus_handle())
1662 .clone()
1663 .tab_stop(self.tab_stop);
1664
1665 if let Some(index) = self.tab_index {
1666 handle = handle.tab_index(index);
1667 }
1668
1669 self.tracked_focus_handle = Some(handle);
1670 }
1671
1672 if let Some(scroll_handle) = self.tracked_scroll_handle.as_ref() {
1673 self.scroll_offset = Some(scroll_handle.0.borrow().offset.clone());
1674 } else if (self.base_style.overflow.x == Some(Overflow::Scroll)
1675 || self.base_style.overflow.y == Some(Overflow::Scroll))
1676 && let Some(element_state) = element_state.as_mut()
1677 {
1678 self.scroll_offset = Some(
1679 element_state
1680 .scroll_offset
1681 .get_or_insert_with(Rc::default)
1682 .clone(),
1683 );
1684 }
1685
1686 let style = self.compute_style_internal(None, element_state.as_mut(), window, cx);
1687 let layout_id = f(style, window, cx);
1688 (layout_id, element_state)
1689 },
1690 )
1691 }
1692
1693 /// Commit the bounds of this element according to this interactivity state's configured styles.
1694 pub fn prepaint<R>(
1695 &mut self,
1696 global_id: Option<&GlobalElementId>,
1697 _inspector_id: Option<&InspectorElementId>,
1698 bounds: Bounds<Pixels>,
1699 content_size: Size<Pixels>,
1700 window: &mut Window,
1701 cx: &mut App,
1702 f: impl FnOnce(&Style, Point<Pixels>, Option<Hitbox>, &mut Window, &mut App) -> R,
1703 ) -> R {
1704 self.content_size = content_size;
1705
1706 #[cfg(any(feature = "inspector", debug_assertions))]
1707 window.with_inspector_state(
1708 _inspector_id,
1709 cx,
1710 |inspector_state: &mut Option<DivInspectorState>, _window| {
1711 if let Some(inspector_state) = inspector_state {
1712 inspector_state.bounds = bounds;
1713 inspector_state.content_size = content_size;
1714 }
1715 },
1716 );
1717
1718 if let Some(focus_handle) = self.tracked_focus_handle.as_ref() {
1719 window.set_focus_handle(focus_handle, cx);
1720 }
1721 window.with_optional_element_state::<InteractiveElementState, _>(
1722 global_id,
1723 |element_state, window| {
1724 let mut element_state =
1725 element_state.map(|element_state| element_state.unwrap_or_default());
1726 let style = self.compute_style_internal(None, element_state.as_mut(), window, cx);
1727
1728 if let Some(element_state) = element_state.as_mut() {
1729 if let Some(clicked_state) = element_state.clicked_state.as_ref() {
1730 let clicked_state = clicked_state.borrow();
1731 self.active = Some(clicked_state.element);
1732 }
1733 if let Some(active_tooltip) = element_state.active_tooltip.as_ref() {
1734 if self.tooltip_builder.is_some() {
1735 self.tooltip_id = set_tooltip_on_window(active_tooltip, window);
1736 } else {
1737 // If there is no longer a tooltip builder, remove the active tooltip.
1738 element_state.active_tooltip.take();
1739 }
1740 }
1741 }
1742
1743 window.with_text_style(style.text_style().cloned(), |window| {
1744 window.with_content_mask(
1745 style.overflow_mask(bounds, window.rem_size()),
1746 |window| {
1747 let hitbox = if self.should_insert_hitbox(&style, window, cx) {
1748 Some(window.insert_hitbox(bounds, self.hitbox_behavior))
1749 } else {
1750 None
1751 };
1752
1753 let scroll_offset =
1754 self.clamp_scroll_position(bounds, &style, window, cx);
1755 let result = f(&style, scroll_offset, hitbox, window, cx);
1756 (result, element_state)
1757 },
1758 )
1759 })
1760 },
1761 )
1762 }
1763
1764 fn should_insert_hitbox(&self, style: &Style, window: &Window, cx: &App) -> bool {
1765 self.hitbox_behavior != HitboxBehavior::Normal
1766 || self.window_control.is_some()
1767 || style.mouse_cursor.is_some()
1768 || self.group.is_some()
1769 || self.scroll_offset.is_some()
1770 || self.tracked_focus_handle.is_some()
1771 || self.hover_style.is_some()
1772 || self.group_hover_style.is_some()
1773 || self.hover_listener.is_some()
1774 || !self.mouse_up_listeners.is_empty()
1775 || !self.mouse_pressure_listeners.is_empty()
1776 || !self.mouse_down_listeners.is_empty()
1777 || !self.mouse_move_listeners.is_empty()
1778 || !self.click_listeners.is_empty()
1779 || !self.scroll_wheel_listeners.is_empty()
1780 || self.drag_listener.is_some()
1781 || !self.drop_listeners.is_empty()
1782 || self.tooltip_builder.is_some()
1783 || window.is_inspector_picking(cx)
1784 }
1785
1786 fn clamp_scroll_position(
1787 &self,
1788 bounds: Bounds<Pixels>,
1789 style: &Style,
1790 window: &mut Window,
1791 _cx: &mut App,
1792 ) -> Point<Pixels> {
1793 fn round_to_two_decimals(pixels: Pixels) -> Pixels {
1794 const ROUNDING_FACTOR: f32 = 100.0;
1795 (pixels * ROUNDING_FACTOR).round() / ROUNDING_FACTOR
1796 }
1797
1798 if let Some(scroll_offset) = self.scroll_offset.as_ref() {
1799 let mut scroll_to_bottom = false;
1800 let mut tracked_scroll_handle = self
1801 .tracked_scroll_handle
1802 .as_ref()
1803 .map(|handle| handle.0.borrow_mut());
1804 if let Some(mut scroll_handle_state) = tracked_scroll_handle.as_deref_mut() {
1805 scroll_handle_state.overflow = style.overflow;
1806 scroll_to_bottom = mem::take(&mut scroll_handle_state.scroll_to_bottom);
1807 }
1808
1809 let rem_size = window.rem_size();
1810 let padding = style.padding.to_pixels(bounds.size.into(), rem_size);
1811 let padding_size = size(padding.left + padding.right, padding.top + padding.bottom);
1812 // The floating point values produced by Taffy and ours often vary
1813 // slightly after ~5 decimal places. This can lead to cases where after
1814 // subtracting these, the container becomes scrollable for less than
1815 // 0.00000x pixels. As we generally don't benefit from a precision that
1816 // high for the maximum scroll, we round the scroll max to 2 decimal
1817 // places here.
1818 let padded_content_size = self.content_size + padding_size;
1819 let scroll_max = (padded_content_size - bounds.size)
1820 .map(round_to_two_decimals)
1821 .max(&Default::default());
1822 // Clamp scroll offset in case scroll max is smaller now (e.g., if children
1823 // were removed or the bounds became larger).
1824 let mut scroll_offset = scroll_offset.borrow_mut();
1825
1826 scroll_offset.x = scroll_offset.x.clamp(-scroll_max.width, px(0.));
1827 if scroll_to_bottom {
1828 scroll_offset.y = -scroll_max.height;
1829 } else {
1830 scroll_offset.y = scroll_offset.y.clamp(-scroll_max.height, px(0.));
1831 }
1832
1833 if let Some(mut scroll_handle_state) = tracked_scroll_handle {
1834 scroll_handle_state.max_offset = scroll_max;
1835 scroll_handle_state.bounds = bounds;
1836 }
1837
1838 *scroll_offset
1839 } else {
1840 Point::default()
1841 }
1842 }
1843
1844 /// Paint this element according to this interactivity state's configured styles
1845 /// and bind the element's mouse and keyboard events.
1846 ///
1847 /// content_size is the size of the content of the element, which may be larger than the
1848 /// element's bounds if the element is scrollable.
1849 ///
1850 /// the final computed style will be passed to the provided function, along
1851 /// with the current scroll offset
1852 pub fn paint(
1853 &mut self,
1854 global_id: Option<&GlobalElementId>,
1855 _inspector_id: Option<&InspectorElementId>,
1856 bounds: Bounds<Pixels>,
1857 hitbox: Option<&Hitbox>,
1858 window: &mut Window,
1859 cx: &mut App,
1860 f: impl FnOnce(&Style, &mut Window, &mut App),
1861 ) {
1862 self.hovered = hitbox.map(|hitbox| hitbox.is_hovered(window));
1863 window.with_optional_element_state::<InteractiveElementState, _>(
1864 global_id,
1865 |element_state, window| {
1866 let mut element_state =
1867 element_state.map(|element_state| element_state.unwrap_or_default());
1868
1869 let style = self.compute_style_internal(hitbox, element_state.as_mut(), window, cx);
1870
1871 #[cfg(any(feature = "test-support", test))]
1872 if let Some(debug_selector) = &self.debug_selector {
1873 window
1874 .next_frame
1875 .debug_bounds
1876 .insert(debug_selector.clone(), bounds);
1877 }
1878
1879 self.paint_hover_group_handler(window, cx);
1880
1881 if style.visibility == Visibility::Hidden {
1882 return ((), element_state);
1883 }
1884
1885 let mut tab_group = None;
1886 if self.tab_group {
1887 tab_group = self.tab_index;
1888 }
1889 if let Some(focus_handle) = &self.tracked_focus_handle {
1890 window.next_frame.tab_stops.insert(focus_handle);
1891 }
1892
1893 window.with_element_opacity(style.opacity, |window| {
1894 style.paint(bounds, window, cx, |window: &mut Window, cx: &mut App| {
1895 window.with_text_style(style.text_style().cloned(), |window| {
1896 window.with_content_mask(
1897 style.overflow_mask(bounds, window.rem_size()),
1898 |window| {
1899 window.with_tab_group(tab_group, |window| {
1900 if let Some(hitbox) = hitbox {
1901 #[cfg(debug_assertions)]
1902 self.paint_debug_info(
1903 global_id, hitbox, &style, window, cx,
1904 );
1905
1906 if let Some(drag) = cx.active_drag.as_ref() {
1907 if let Some(mouse_cursor) = drag.cursor_style {
1908 window.set_window_cursor_style(mouse_cursor);
1909 }
1910 } else {
1911 if let Some(mouse_cursor) = style.mouse_cursor {
1912 window.set_cursor_style(mouse_cursor, hitbox);
1913 }
1914 }
1915
1916 if let Some(group) = self.group.clone() {
1917 GroupHitboxes::push(group, hitbox.id, cx);
1918 }
1919
1920 if let Some(area) = self.window_control {
1921 window.insert_window_control_hitbox(
1922 area,
1923 hitbox.clone(),
1924 );
1925 }
1926
1927 self.paint_mouse_listeners(
1928 hitbox,
1929 element_state.as_mut(),
1930 window,
1931 cx,
1932 );
1933 self.paint_scroll_listener(hitbox, &style, window, cx);
1934 }
1935
1936 self.paint_keyboard_listeners(window, cx);
1937 f(&style, window, cx);
1938
1939 if let Some(_hitbox) = hitbox {
1940 #[cfg(any(feature = "inspector", debug_assertions))]
1941 window.insert_inspector_hitbox(
1942 _hitbox.id,
1943 _inspector_id,
1944 cx,
1945 );
1946
1947 if let Some(group) = self.group.as_ref() {
1948 GroupHitboxes::pop(group, cx);
1949 }
1950 }
1951 })
1952 },
1953 );
1954 });
1955 });
1956 });
1957
1958 ((), element_state)
1959 },
1960 );
1961 }
1962
1963 #[cfg(debug_assertions)]
1964 fn paint_debug_info(
1965 &self,
1966 global_id: Option<&GlobalElementId>,
1967 hitbox: &Hitbox,
1968 style: &Style,
1969 window: &mut Window,
1970 cx: &mut App,
1971 ) {
1972 use crate::{BorderStyle, TextAlign};
1973
1974 if global_id.is_some()
1975 && (style.debug || style.debug_below || cx.has_global::<crate::DebugBelow>())
1976 && hitbox.is_hovered(window)
1977 {
1978 const FONT_SIZE: crate::Pixels = crate::Pixels(10.);
1979 let element_id = format!("{:?}", global_id.unwrap());
1980 let str_len = element_id.len();
1981
1982 let render_debug_text = |window: &mut Window| {
1983 if let Some(text) = window
1984 .text_system()
1985 .shape_text(
1986 element_id.into(),
1987 FONT_SIZE,
1988 &[window.text_style().to_run(str_len)],
1989 None,
1990 None,
1991 )
1992 .ok()
1993 .and_then(|mut text| text.pop())
1994 {
1995 text.paint(hitbox.origin, FONT_SIZE, TextAlign::Left, None, window, cx)
1996 .ok();
1997
1998 let text_bounds = crate::Bounds {
1999 origin: hitbox.origin,
2000 size: text.size(FONT_SIZE),
2001 };
2002 if self.source_location.is_some()
2003 && text_bounds.contains(&window.mouse_position())
2004 && window.modifiers().secondary()
2005 {
2006 let secondary_held = window.modifiers().secondary();
2007 window.on_key_event({
2008 move |e: &crate::ModifiersChangedEvent, _phase, window, _cx| {
2009 if e.modifiers.secondary() != secondary_held
2010 && text_bounds.contains(&window.mouse_position())
2011 {
2012 window.refresh();
2013 }
2014 }
2015 });
2016
2017 let was_hovered = hitbox.is_hovered(window);
2018 let current_view = window.current_view();
2019 window.on_mouse_event({
2020 let hitbox = hitbox.clone();
2021 move |_: &MouseMoveEvent, phase, window, cx| {
2022 if phase == DispatchPhase::Capture {
2023 let hovered = hitbox.is_hovered(window);
2024 if hovered != was_hovered {
2025 cx.notify(current_view)
2026 }
2027 }
2028 }
2029 });
2030
2031 window.on_mouse_event({
2032 let hitbox = hitbox.clone();
2033 let location = self.source_location.unwrap();
2034 move |e: &crate::MouseDownEvent, phase, window, cx| {
2035 if text_bounds.contains(&e.position)
2036 && phase.capture()
2037 && hitbox.is_hovered(window)
2038 {
2039 cx.stop_propagation();
2040 let Ok(dir) = std::env::current_dir() else {
2041 return;
2042 };
2043
2044 eprintln!(
2045 "This element was created at:\n{}:{}:{}",
2046 dir.join(location.file()).to_string_lossy(),
2047 location.line(),
2048 location.column()
2049 );
2050 }
2051 }
2052 });
2053 window.paint_quad(crate::outline(
2054 crate::Bounds {
2055 origin: hitbox.origin
2056 + crate::point(crate::px(0.), FONT_SIZE - px(2.)),
2057 size: crate::Size {
2058 width: text_bounds.size.width,
2059 height: crate::px(1.),
2060 },
2061 },
2062 crate::red(),
2063 BorderStyle::default(),
2064 ))
2065 }
2066 }
2067 };
2068
2069 window.with_text_style(
2070 Some(crate::TextStyleRefinement {
2071 color: Some(crate::red()),
2072 line_height: Some(FONT_SIZE.into()),
2073 background_color: Some(crate::white()),
2074 ..Default::default()
2075 }),
2076 render_debug_text,
2077 )
2078 }
2079 }
2080
2081 fn paint_mouse_listeners(
2082 &mut self,
2083 hitbox: &Hitbox,
2084 element_state: Option<&mut InteractiveElementState>,
2085 window: &mut Window,
2086 cx: &mut App,
2087 ) {
2088 let is_focused = self
2089 .tracked_focus_handle
2090 .as_ref()
2091 .map(|handle| handle.is_focused(window))
2092 .unwrap_or(false);
2093
2094 // If this element can be focused, register a mouse down listener
2095 // that will automatically transfer focus when hitting the element.
2096 // This behavior can be suppressed by using `cx.prevent_default()`.
2097 if let Some(focus_handle) = self.tracked_focus_handle.clone() {
2098 let hitbox = hitbox.clone();
2099 window.on_mouse_event(move |_: &MouseDownEvent, phase, window, _| {
2100 if phase == DispatchPhase::Bubble
2101 && hitbox.is_hovered(window)
2102 && !window.default_prevented()
2103 {
2104 window.focus(&focus_handle);
2105 // If there is a parent that is also focusable, prevent it
2106 // from transferring focus because we already did so.
2107 window.prevent_default();
2108 }
2109 });
2110 }
2111
2112 for listener in self.mouse_down_listeners.drain(..) {
2113 let hitbox = hitbox.clone();
2114 window.on_mouse_event(move |event: &MouseDownEvent, phase, window, cx| {
2115 listener(event, phase, &hitbox, window, cx);
2116 })
2117 }
2118
2119 for listener in self.mouse_up_listeners.drain(..) {
2120 let hitbox = hitbox.clone();
2121 window.on_mouse_event(move |event: &MouseUpEvent, phase, window, cx| {
2122 listener(event, phase, &hitbox, window, cx);
2123 })
2124 }
2125
2126 for listener in self.mouse_pressure_listeners.drain(..) {
2127 let hitbox = hitbox.clone();
2128 window.on_mouse_event(move |event: &MousePressureEvent, phase, window, cx| {
2129 listener(event, phase, &hitbox, window, cx);
2130 })
2131 }
2132
2133 for listener in self.mouse_move_listeners.drain(..) {
2134 let hitbox = hitbox.clone();
2135 window.on_mouse_event(move |event: &MouseMoveEvent, phase, window, cx| {
2136 listener(event, phase, &hitbox, window, cx);
2137 })
2138 }
2139
2140 for listener in self.scroll_wheel_listeners.drain(..) {
2141 let hitbox = hitbox.clone();
2142 window.on_mouse_event(move |event: &ScrollWheelEvent, phase, window, cx| {
2143 listener(event, phase, &hitbox, window, cx);
2144 })
2145 }
2146
2147 if self.hover_style.is_some()
2148 || self.base_style.mouse_cursor.is_some()
2149 || cx.active_drag.is_some() && !self.drag_over_styles.is_empty()
2150 {
2151 let hitbox = hitbox.clone();
2152 let was_hovered = hitbox.is_hovered(window);
2153 let current_view = window.current_view();
2154 window.on_mouse_event(move |_: &MouseMoveEvent, phase, window, cx| {
2155 let hovered = hitbox.is_hovered(window);
2156 if phase == DispatchPhase::Capture && hovered != was_hovered {
2157 cx.notify(current_view);
2158 }
2159 });
2160 }
2161 let drag_cursor_style = self.base_style.as_ref().mouse_cursor;
2162
2163 let mut drag_listener = mem::take(&mut self.drag_listener);
2164 let drop_listeners = mem::take(&mut self.drop_listeners);
2165 let click_listeners = mem::take(&mut self.click_listeners);
2166 let can_drop_predicate = mem::take(&mut self.can_drop_predicate);
2167
2168 if !drop_listeners.is_empty() {
2169 let hitbox = hitbox.clone();
2170 window.on_mouse_event({
2171 move |_: &MouseUpEvent, phase, window, cx| {
2172 if let Some(drag) = &cx.active_drag
2173 && phase == DispatchPhase::Bubble
2174 && hitbox.is_hovered(window)
2175 {
2176 let drag_state_type = drag.value.as_ref().type_id();
2177 for (drop_state_type, listener) in &drop_listeners {
2178 if *drop_state_type == drag_state_type {
2179 let drag = cx
2180 .active_drag
2181 .take()
2182 .expect("checked for type drag state type above");
2183
2184 let mut can_drop = true;
2185 if let Some(predicate) = &can_drop_predicate {
2186 can_drop = predicate(drag.value.as_ref(), window, cx);
2187 }
2188
2189 if can_drop {
2190 listener(drag.value.as_ref(), window, cx);
2191 window.refresh();
2192 cx.stop_propagation();
2193 }
2194 }
2195 }
2196 }
2197 }
2198 });
2199 }
2200
2201 if let Some(element_state) = element_state {
2202 if !click_listeners.is_empty() || drag_listener.is_some() {
2203 let pending_mouse_down = element_state
2204 .pending_mouse_down
2205 .get_or_insert_with(Default::default)
2206 .clone();
2207
2208 let clicked_state = element_state
2209 .clicked_state
2210 .get_or_insert_with(Default::default)
2211 .clone();
2212
2213 window.on_mouse_event({
2214 let pending_mouse_down = pending_mouse_down.clone();
2215 let hitbox = hitbox.clone();
2216 move |event: &MouseDownEvent, phase, window, _cx| {
2217 if phase == DispatchPhase::Bubble
2218 && event.button == MouseButton::Left
2219 && hitbox.is_hovered(window)
2220 {
2221 *pending_mouse_down.borrow_mut() = Some(event.clone());
2222 window.refresh();
2223 }
2224 }
2225 });
2226
2227 window.on_mouse_event({
2228 let pending_mouse_down = pending_mouse_down.clone();
2229 let hitbox = hitbox.clone();
2230 move |event: &MouseMoveEvent, phase, window, cx| {
2231 if phase == DispatchPhase::Capture {
2232 return;
2233 }
2234
2235 let mut pending_mouse_down = pending_mouse_down.borrow_mut();
2236 if let Some(mouse_down) = pending_mouse_down.clone()
2237 && !cx.has_active_drag()
2238 && (event.position - mouse_down.position).magnitude() > DRAG_THRESHOLD
2239 && let Some((drag_value, drag_listener)) = drag_listener.take()
2240 {
2241 *clicked_state.borrow_mut() = ElementClickedState::default();
2242 let cursor_offset = event.position - hitbox.origin;
2243 let drag =
2244 (drag_listener)(drag_value.as_ref(), cursor_offset, window, cx);
2245 cx.active_drag = Some(AnyDrag {
2246 view: drag,
2247 value: drag_value,
2248 cursor_offset,
2249 cursor_style: drag_cursor_style,
2250 });
2251 pending_mouse_down.take();
2252 window.refresh();
2253 cx.stop_propagation();
2254 }
2255 }
2256 });
2257
2258 if is_focused {
2259 // Press enter, space to trigger click, when the element is focused.
2260 window.on_key_event({
2261 let click_listeners = click_listeners.clone();
2262 let hitbox = hitbox.clone();
2263 move |event: &KeyUpEvent, phase, window, cx| {
2264 if phase.bubble() && !window.default_prevented() {
2265 let stroke = &event.keystroke;
2266 let keyboard_button = if stroke.key.eq("enter") {
2267 Some(KeyboardButton::Enter)
2268 } else if stroke.key.eq("space") {
2269 Some(KeyboardButton::Space)
2270 } else {
2271 None
2272 };
2273
2274 if let Some(button) = keyboard_button
2275 && !stroke.modifiers.modified()
2276 {
2277 let click_event = ClickEvent::Keyboard(KeyboardClickEvent {
2278 button,
2279 bounds: hitbox.bounds,
2280 });
2281
2282 for listener in &click_listeners {
2283 listener(&click_event, window, cx);
2284 }
2285 }
2286 }
2287 }
2288 });
2289 }
2290
2291 window.on_mouse_event({
2292 let mut captured_mouse_down = None;
2293 let hitbox = hitbox.clone();
2294 move |event: &MouseUpEvent, phase, window, cx| match phase {
2295 // Clear the pending mouse down during the capture phase,
2296 // so that it happens even if another event handler stops
2297 // propagation.
2298 DispatchPhase::Capture => {
2299 let mut pending_mouse_down = pending_mouse_down.borrow_mut();
2300 if pending_mouse_down.is_some() && hitbox.is_hovered(window) {
2301 captured_mouse_down = pending_mouse_down.take();
2302 window.refresh();
2303 } else if pending_mouse_down.is_some() {
2304 // Clear the pending mouse down event (without firing click handlers)
2305 // if the hitbox is not being hovered.
2306 // This avoids dragging elements that changed their position
2307 // immediately after being clicked.
2308 // See https://github.com/zed-industries/zed/issues/24600 for more details
2309 pending_mouse_down.take();
2310 window.refresh();
2311 }
2312 }
2313 // Fire click handlers during the bubble phase.
2314 DispatchPhase::Bubble => {
2315 if let Some(mouse_down) = captured_mouse_down.take() {
2316 let mouse_click = ClickEvent::Mouse(MouseClickEvent {
2317 down: mouse_down,
2318 up: event.clone(),
2319 });
2320 for listener in &click_listeners {
2321 listener(&mouse_click, window, cx);
2322 }
2323 }
2324 }
2325 }
2326 });
2327 }
2328
2329 if let Some(hover_listener) = self.hover_listener.take() {
2330 let hitbox = hitbox.clone();
2331 let was_hovered = element_state
2332 .hover_state
2333 .get_or_insert_with(Default::default)
2334 .clone();
2335 let has_mouse_down = element_state
2336 .pending_mouse_down
2337 .get_or_insert_with(Default::default)
2338 .clone();
2339
2340 window.on_mouse_event(move |_: &MouseMoveEvent, phase, window, cx| {
2341 if phase != DispatchPhase::Bubble {
2342 return;
2343 }
2344 let is_hovered = has_mouse_down.borrow().is_none()
2345 && !cx.has_active_drag()
2346 && hitbox.is_hovered(window);
2347 let mut was_hovered = was_hovered.borrow_mut();
2348
2349 if is_hovered != *was_hovered {
2350 *was_hovered = is_hovered;
2351 drop(was_hovered);
2352
2353 hover_listener(&is_hovered, window, cx);
2354 }
2355 });
2356 }
2357
2358 if let Some(tooltip_builder) = self.tooltip_builder.take() {
2359 let active_tooltip = element_state
2360 .active_tooltip
2361 .get_or_insert_with(Default::default)
2362 .clone();
2363 let pending_mouse_down = element_state
2364 .pending_mouse_down
2365 .get_or_insert_with(Default::default)
2366 .clone();
2367
2368 let tooltip_is_hoverable = tooltip_builder.hoverable;
2369 let build_tooltip = Rc::new(move |window: &mut Window, cx: &mut App| {
2370 Some(((tooltip_builder.build)(window, cx), tooltip_is_hoverable))
2371 });
2372 // Use bounds instead of testing hitbox since this is called during prepaint.
2373 let check_is_hovered_during_prepaint = Rc::new({
2374 let pending_mouse_down = pending_mouse_down.clone();
2375 let source_bounds = hitbox.bounds;
2376 move |window: &Window| {
2377 pending_mouse_down.borrow().is_none()
2378 && source_bounds.contains(&window.mouse_position())
2379 }
2380 });
2381 let check_is_hovered = Rc::new({
2382 let hitbox = hitbox.clone();
2383 move |window: &Window| {
2384 pending_mouse_down.borrow().is_none() && hitbox.is_hovered(window)
2385 }
2386 });
2387 register_tooltip_mouse_handlers(
2388 &active_tooltip,
2389 self.tooltip_id,
2390 build_tooltip,
2391 check_is_hovered,
2392 check_is_hovered_during_prepaint,
2393 window,
2394 );
2395 }
2396
2397 let active_state = element_state
2398 .clicked_state
2399 .get_or_insert_with(Default::default)
2400 .clone();
2401 if active_state.borrow().is_clicked() {
2402 window.on_mouse_event(move |_: &MouseUpEvent, phase, window, _cx| {
2403 if phase == DispatchPhase::Capture {
2404 *active_state.borrow_mut() = ElementClickedState::default();
2405 window.refresh();
2406 }
2407 });
2408 } else {
2409 let active_group_hitbox = self
2410 .group_active_style
2411 .as_ref()
2412 .and_then(|group_active| GroupHitboxes::get(&group_active.group, cx));
2413 let hitbox = hitbox.clone();
2414 window.on_mouse_event(move |_: &MouseDownEvent, phase, window, _cx| {
2415 if phase == DispatchPhase::Bubble && !window.default_prevented() {
2416 let group_hovered = active_group_hitbox
2417 .is_some_and(|group_hitbox_id| group_hitbox_id.is_hovered(window));
2418 let element_hovered = hitbox.is_hovered(window);
2419 if group_hovered || element_hovered {
2420 *active_state.borrow_mut() = ElementClickedState {
2421 group: group_hovered,
2422 element: element_hovered,
2423 };
2424 window.refresh();
2425 }
2426 }
2427 });
2428 }
2429 }
2430 }
2431
2432 fn paint_keyboard_listeners(&mut self, window: &mut Window, _cx: &mut App) {
2433 let key_down_listeners = mem::take(&mut self.key_down_listeners);
2434 let key_up_listeners = mem::take(&mut self.key_up_listeners);
2435 let modifiers_changed_listeners = mem::take(&mut self.modifiers_changed_listeners);
2436 let action_listeners = mem::take(&mut self.action_listeners);
2437 if let Some(context) = self.key_context.clone() {
2438 window.set_key_context(context);
2439 }
2440
2441 for listener in key_down_listeners {
2442 window.on_key_event(move |event: &KeyDownEvent, phase, window, cx| {
2443 listener(event, phase, window, cx);
2444 })
2445 }
2446
2447 for listener in key_up_listeners {
2448 window.on_key_event(move |event: &KeyUpEvent, phase, window, cx| {
2449 listener(event, phase, window, cx);
2450 })
2451 }
2452
2453 for listener in modifiers_changed_listeners {
2454 window.on_modifiers_changed(move |event: &ModifiersChangedEvent, window, cx| {
2455 listener(event, window, cx);
2456 })
2457 }
2458
2459 for (action_type, listener) in action_listeners {
2460 window.on_action(action_type, listener)
2461 }
2462 }
2463
2464 fn paint_hover_group_handler(&self, window: &mut Window, cx: &mut App) {
2465 let group_hitbox = self
2466 .group_hover_style
2467 .as_ref()
2468 .and_then(|group_hover| GroupHitboxes::get(&group_hover.group, cx));
2469
2470 if let Some(group_hitbox) = group_hitbox {
2471 let was_hovered = group_hitbox.is_hovered(window);
2472 let current_view = window.current_view();
2473 window.on_mouse_event(move |_: &MouseMoveEvent, phase, window, cx| {
2474 let hovered = group_hitbox.is_hovered(window);
2475 if phase == DispatchPhase::Capture && hovered != was_hovered {
2476 cx.notify(current_view);
2477 }
2478 });
2479 }
2480 }
2481
2482 fn paint_scroll_listener(
2483 &self,
2484 hitbox: &Hitbox,
2485 style: &Style,
2486 window: &mut Window,
2487 _cx: &mut App,
2488 ) {
2489 if let Some(scroll_offset) = self.scroll_offset.clone() {
2490 let overflow = style.overflow;
2491 let allow_concurrent_scroll = style.allow_concurrent_scroll;
2492 let restrict_scroll_to_axis = style.restrict_scroll_to_axis;
2493 let line_height = window.line_height();
2494 let hitbox = hitbox.clone();
2495 let current_view = window.current_view();
2496 window.on_mouse_event(move |event: &ScrollWheelEvent, phase, window, cx| {
2497 if phase == DispatchPhase::Bubble && hitbox.should_handle_scroll(window) {
2498 let mut scroll_offset = scroll_offset.borrow_mut();
2499 let old_scroll_offset = *scroll_offset;
2500 let delta = event.delta.pixel_delta(line_height);
2501
2502 let mut delta_x = Pixels::ZERO;
2503 if overflow.x == Overflow::Scroll {
2504 if !delta.x.is_zero() {
2505 delta_x = delta.x;
2506 } else if !restrict_scroll_to_axis && overflow.y != Overflow::Scroll {
2507 delta_x = delta.y;
2508 }
2509 }
2510 let mut delta_y = Pixels::ZERO;
2511 if overflow.y == Overflow::Scroll {
2512 if !delta.y.is_zero() {
2513 delta_y = delta.y;
2514 } else if !restrict_scroll_to_axis && overflow.x != Overflow::Scroll {
2515 delta_y = delta.x;
2516 }
2517 }
2518 if !allow_concurrent_scroll && !delta_x.is_zero() && !delta_y.is_zero() {
2519 if delta_x.abs() > delta_y.abs() {
2520 delta_y = Pixels::ZERO;
2521 } else {
2522 delta_x = Pixels::ZERO;
2523 }
2524 }
2525 scroll_offset.y += delta_y;
2526 scroll_offset.x += delta_x;
2527 if *scroll_offset != old_scroll_offset {
2528 cx.notify(current_view);
2529 }
2530 }
2531 });
2532 }
2533 }
2534
2535 /// Compute the visual style for this element, based on the current bounds and the element's state.
2536 pub fn compute_style(
2537 &self,
2538 global_id: Option<&GlobalElementId>,
2539 hitbox: Option<&Hitbox>,
2540 window: &mut Window,
2541 cx: &mut App,
2542 ) -> Style {
2543 window.with_optional_element_state(global_id, |element_state, window| {
2544 let mut element_state =
2545 element_state.map(|element_state| element_state.unwrap_or_default());
2546 let style = self.compute_style_internal(hitbox, element_state.as_mut(), window, cx);
2547 (style, element_state)
2548 })
2549 }
2550
2551 /// Called from internal methods that have already called with_element_state.
2552 fn compute_style_internal(
2553 &self,
2554 hitbox: Option<&Hitbox>,
2555 element_state: Option<&mut InteractiveElementState>,
2556 window: &mut Window,
2557 cx: &mut App,
2558 ) -> Style {
2559 let mut style = Style::default();
2560 style.refine(&self.base_style);
2561
2562 if let Some(focus_handle) = self.tracked_focus_handle.as_ref() {
2563 if let Some(in_focus_style) = self.in_focus_style.as_ref()
2564 && focus_handle.within_focused(window, cx)
2565 {
2566 style.refine(in_focus_style);
2567 }
2568
2569 if let Some(focus_style) = self.focus_style.as_ref()
2570 && focus_handle.is_focused(window)
2571 {
2572 style.refine(focus_style);
2573 }
2574
2575 if let Some(focus_visible_style) = self.focus_visible_style.as_ref()
2576 && focus_handle.is_focused(window)
2577 && window.last_input_was_keyboard()
2578 {
2579 style.refine(focus_visible_style);
2580 }
2581 }
2582
2583 if let Some(hitbox) = hitbox {
2584 if !cx.has_active_drag() {
2585 if let Some(group_hover) = self.group_hover_style.as_ref()
2586 && let Some(group_hitbox_id) = GroupHitboxes::get(&group_hover.group, cx)
2587 && group_hitbox_id.is_hovered(window)
2588 {
2589 style.refine(&group_hover.style);
2590 }
2591
2592 if let Some(hover_style) = self.hover_style.as_ref()
2593 && hitbox.is_hovered(window)
2594 {
2595 style.refine(hover_style);
2596 }
2597 }
2598
2599 if let Some(drag) = cx.active_drag.take() {
2600 let mut can_drop = true;
2601 if let Some(can_drop_predicate) = &self.can_drop_predicate {
2602 can_drop = can_drop_predicate(drag.value.as_ref(), window, cx);
2603 }
2604
2605 if can_drop {
2606 for (state_type, group_drag_style) in &self.group_drag_over_styles {
2607 if let Some(group_hitbox_id) =
2608 GroupHitboxes::get(&group_drag_style.group, cx)
2609 && *state_type == drag.value.as_ref().type_id()
2610 && group_hitbox_id.is_hovered(window)
2611 {
2612 style.refine(&group_drag_style.style);
2613 }
2614 }
2615
2616 for (state_type, build_drag_over_style) in &self.drag_over_styles {
2617 if *state_type == drag.value.as_ref().type_id() && hitbox.is_hovered(window)
2618 {
2619 style.refine(&build_drag_over_style(drag.value.as_ref(), window, cx));
2620 }
2621 }
2622 }
2623
2624 style.mouse_cursor = drag.cursor_style;
2625 cx.active_drag = Some(drag);
2626 }
2627 }
2628
2629 if let Some(element_state) = element_state {
2630 let clicked_state = element_state
2631 .clicked_state
2632 .get_or_insert_with(Default::default)
2633 .borrow();
2634 if clicked_state.group
2635 && let Some(group) = self.group_active_style.as_ref()
2636 {
2637 style.refine(&group.style)
2638 }
2639
2640 if let Some(active_style) = self.active_style.as_ref()
2641 && clicked_state.element
2642 {
2643 style.refine(active_style)
2644 }
2645 }
2646
2647 style
2648 }
2649}
2650
2651/// The per-frame state of an interactive element. Used for tracking stateful interactions like clicks
2652/// and scroll offsets.
2653#[derive(Default)]
2654pub struct InteractiveElementState {
2655 pub(crate) focus_handle: Option<FocusHandle>,
2656 pub(crate) clicked_state: Option<Rc<RefCell<ElementClickedState>>>,
2657 pub(crate) hover_state: Option<Rc<RefCell<bool>>>,
2658 pub(crate) pending_mouse_down: Option<Rc<RefCell<Option<MouseDownEvent>>>>,
2659 pub(crate) scroll_offset: Option<Rc<RefCell<Point<Pixels>>>>,
2660 pub(crate) active_tooltip: Option<Rc<RefCell<Option<ActiveTooltip>>>>,
2661}
2662
2663/// Whether or not the element or a group that contains it is clicked by the mouse.
2664#[derive(Copy, Clone, Default, Eq, PartialEq)]
2665pub struct ElementClickedState {
2666 /// True if this element's group has been clicked, false otherwise
2667 pub group: bool,
2668
2669 /// True if this element has been clicked, false otherwise
2670 pub element: bool,
2671}
2672
2673impl ElementClickedState {
2674 fn is_clicked(&self) -> bool {
2675 self.group || self.element
2676 }
2677}
2678
2679pub(crate) enum ActiveTooltip {
2680 /// Currently delaying before showing the tooltip.
2681 WaitingForShow { _task: Task<()> },
2682 /// Tooltip is visible, element was hovered or for hoverable tooltips, the tooltip was hovered.
2683 Visible {
2684 tooltip: AnyTooltip,
2685 is_hoverable: bool,
2686 },
2687 /// Tooltip is visible and hoverable, but the mouse is no longer hovering. Currently delaying
2688 /// before hiding it.
2689 WaitingForHide {
2690 tooltip: AnyTooltip,
2691 _task: Task<()>,
2692 },
2693}
2694
2695pub(crate) fn clear_active_tooltip(
2696 active_tooltip: &Rc<RefCell<Option<ActiveTooltip>>>,
2697 window: &mut Window,
2698) {
2699 match active_tooltip.borrow_mut().take() {
2700 None => {}
2701 Some(ActiveTooltip::WaitingForShow { .. }) => {}
2702 Some(ActiveTooltip::Visible { .. }) => window.refresh(),
2703 Some(ActiveTooltip::WaitingForHide { .. }) => window.refresh(),
2704 }
2705}
2706
2707pub(crate) fn clear_active_tooltip_if_not_hoverable(
2708 active_tooltip: &Rc<RefCell<Option<ActiveTooltip>>>,
2709 window: &mut Window,
2710) {
2711 let should_clear = match active_tooltip.borrow().as_ref() {
2712 None => false,
2713 Some(ActiveTooltip::WaitingForShow { .. }) => false,
2714 Some(ActiveTooltip::Visible { is_hoverable, .. }) => !is_hoverable,
2715 Some(ActiveTooltip::WaitingForHide { .. }) => false,
2716 };
2717 if should_clear {
2718 active_tooltip.borrow_mut().take();
2719 window.refresh();
2720 }
2721}
2722
2723pub(crate) fn set_tooltip_on_window(
2724 active_tooltip: &Rc<RefCell<Option<ActiveTooltip>>>,
2725 window: &mut Window,
2726) -> Option<TooltipId> {
2727 let tooltip = match active_tooltip.borrow().as_ref() {
2728 None => return None,
2729 Some(ActiveTooltip::WaitingForShow { .. }) => return None,
2730 Some(ActiveTooltip::Visible { tooltip, .. }) => tooltip.clone(),
2731 Some(ActiveTooltip::WaitingForHide { tooltip, .. }) => tooltip.clone(),
2732 };
2733 Some(window.set_tooltip(tooltip))
2734}
2735
2736pub(crate) fn register_tooltip_mouse_handlers(
2737 active_tooltip: &Rc<RefCell<Option<ActiveTooltip>>>,
2738 tooltip_id: Option<TooltipId>,
2739 build_tooltip: Rc<dyn Fn(&mut Window, &mut App) -> Option<(AnyView, bool)>>,
2740 check_is_hovered: Rc<dyn Fn(&Window) -> bool>,
2741 check_is_hovered_during_prepaint: Rc<dyn Fn(&Window) -> bool>,
2742 window: &mut Window,
2743) {
2744 window.on_mouse_event({
2745 let active_tooltip = active_tooltip.clone();
2746 let build_tooltip = build_tooltip.clone();
2747 let check_is_hovered = check_is_hovered.clone();
2748 move |_: &MouseMoveEvent, phase, window, cx| {
2749 handle_tooltip_mouse_move(
2750 &active_tooltip,
2751 &build_tooltip,
2752 &check_is_hovered,
2753 &check_is_hovered_during_prepaint,
2754 phase,
2755 window,
2756 cx,
2757 )
2758 }
2759 });
2760
2761 window.on_mouse_event({
2762 let active_tooltip = active_tooltip.clone();
2763 move |_: &MouseDownEvent, _phase, window: &mut Window, _cx| {
2764 if !tooltip_id.is_some_and(|tooltip_id| tooltip_id.is_hovered(window)) {
2765 clear_active_tooltip_if_not_hoverable(&active_tooltip, window);
2766 }
2767 }
2768 });
2769
2770 window.on_mouse_event({
2771 let active_tooltip = active_tooltip.clone();
2772 move |_: &ScrollWheelEvent, _phase, window: &mut Window, _cx| {
2773 if !tooltip_id.is_some_and(|tooltip_id| tooltip_id.is_hovered(window)) {
2774 clear_active_tooltip_if_not_hoverable(&active_tooltip, window);
2775 }
2776 }
2777 });
2778}
2779
2780/// Handles displaying tooltips when an element is hovered.
2781///
2782/// The mouse hovering logic also relies on being called from window prepaint in order to handle the
2783/// case where the element the tooltip is on is not rendered - in that case its mouse listeners are
2784/// also not registered. During window prepaint, the hitbox information is not available, so
2785/// `check_is_hovered_during_prepaint` is used which bases the check off of the absolute bounds of
2786/// the element.
2787///
2788/// TODO: There's a minor bug due to the use of absolute bounds while checking during prepaint - it
2789/// does not know if the hitbox is occluded. In the case where a tooltip gets displayed and then
2790/// gets occluded after display, it will stick around until the mouse exits the hover bounds.
2791fn handle_tooltip_mouse_move(
2792 active_tooltip: &Rc<RefCell<Option<ActiveTooltip>>>,
2793 build_tooltip: &Rc<dyn Fn(&mut Window, &mut App) -> Option<(AnyView, bool)>>,
2794 check_is_hovered: &Rc<dyn Fn(&Window) -> bool>,
2795 check_is_hovered_during_prepaint: &Rc<dyn Fn(&Window) -> bool>,
2796 phase: DispatchPhase,
2797 window: &mut Window,
2798 cx: &mut App,
2799) {
2800 // Separates logic for what mutation should occur from applying it, to avoid overlapping
2801 // RefCell borrows.
2802 enum Action {
2803 None,
2804 CancelShow,
2805 ScheduleShow,
2806 }
2807
2808 let action = match active_tooltip.borrow().as_ref() {
2809 None => {
2810 let is_hovered = check_is_hovered(window);
2811 if is_hovered && phase.bubble() {
2812 Action::ScheduleShow
2813 } else {
2814 Action::None
2815 }
2816 }
2817 Some(ActiveTooltip::WaitingForShow { .. }) => {
2818 let is_hovered = check_is_hovered(window);
2819 if is_hovered {
2820 Action::None
2821 } else {
2822 Action::CancelShow
2823 }
2824 }
2825 // These are handled in check_visible_and_update.
2826 Some(ActiveTooltip::Visible { .. }) | Some(ActiveTooltip::WaitingForHide { .. }) => {
2827 Action::None
2828 }
2829 };
2830
2831 match action {
2832 Action::None => {}
2833 Action::CancelShow => {
2834 // Cancel waiting to show tooltip when it is no longer hovered.
2835 active_tooltip.borrow_mut().take();
2836 }
2837 Action::ScheduleShow => {
2838 let delayed_show_task = window.spawn(cx, {
2839 let active_tooltip = active_tooltip.clone();
2840 let build_tooltip = build_tooltip.clone();
2841 let check_is_hovered_during_prepaint = check_is_hovered_during_prepaint.clone();
2842 async move |cx| {
2843 cx.background_executor().timer(TOOLTIP_SHOW_DELAY).await;
2844 cx.update(|window, cx| {
2845 let new_tooltip =
2846 build_tooltip(window, cx).map(|(view, tooltip_is_hoverable)| {
2847 let active_tooltip = active_tooltip.clone();
2848 ActiveTooltip::Visible {
2849 tooltip: AnyTooltip {
2850 view,
2851 mouse_position: window.mouse_position(),
2852 check_visible_and_update: Rc::new(
2853 move |tooltip_bounds, window, cx| {
2854 handle_tooltip_check_visible_and_update(
2855 &active_tooltip,
2856 tooltip_is_hoverable,
2857 &check_is_hovered_during_prepaint,
2858 tooltip_bounds,
2859 window,
2860 cx,
2861 )
2862 },
2863 ),
2864 },
2865 is_hoverable: tooltip_is_hoverable,
2866 }
2867 });
2868 *active_tooltip.borrow_mut() = new_tooltip;
2869 window.refresh();
2870 })
2871 .ok();
2872 }
2873 });
2874 active_tooltip
2875 .borrow_mut()
2876 .replace(ActiveTooltip::WaitingForShow {
2877 _task: delayed_show_task,
2878 });
2879 }
2880 }
2881}
2882
2883/// Returns a callback which will be called by window prepaint to update tooltip visibility. The
2884/// purpose of doing this logic here instead of the mouse move handler is that the mouse move
2885/// handler won't get called when the element is not painted (e.g. via use of `visible_on_hover`).
2886fn handle_tooltip_check_visible_and_update(
2887 active_tooltip: &Rc<RefCell<Option<ActiveTooltip>>>,
2888 tooltip_is_hoverable: bool,
2889 check_is_hovered: &Rc<dyn Fn(&Window) -> bool>,
2890 tooltip_bounds: Bounds<Pixels>,
2891 window: &mut Window,
2892 cx: &mut App,
2893) -> bool {
2894 // Separates logic for what mutation should occur from applying it, to avoid overlapping RefCell
2895 // borrows.
2896 enum Action {
2897 None,
2898 Hide,
2899 ScheduleHide(AnyTooltip),
2900 CancelHide(AnyTooltip),
2901 }
2902
2903 let is_hovered = check_is_hovered(window)
2904 || (tooltip_is_hoverable && tooltip_bounds.contains(&window.mouse_position()));
2905 let action = match active_tooltip.borrow().as_ref() {
2906 Some(ActiveTooltip::Visible { tooltip, .. }) => {
2907 if is_hovered {
2908 Action::None
2909 } else {
2910 if tooltip_is_hoverable {
2911 Action::ScheduleHide(tooltip.clone())
2912 } else {
2913 Action::Hide
2914 }
2915 }
2916 }
2917 Some(ActiveTooltip::WaitingForHide { tooltip, .. }) => {
2918 if is_hovered {
2919 Action::CancelHide(tooltip.clone())
2920 } else {
2921 Action::None
2922 }
2923 }
2924 None | Some(ActiveTooltip::WaitingForShow { .. }) => Action::None,
2925 };
2926
2927 match action {
2928 Action::None => {}
2929 Action::Hide => clear_active_tooltip(active_tooltip, window),
2930 Action::ScheduleHide(tooltip) => {
2931 let delayed_hide_task = window.spawn(cx, {
2932 let active_tooltip = active_tooltip.clone();
2933 async move |cx| {
2934 cx.background_executor()
2935 .timer(HOVERABLE_TOOLTIP_HIDE_DELAY)
2936 .await;
2937 if active_tooltip.borrow_mut().take().is_some() {
2938 cx.update(|window, _cx| window.refresh()).ok();
2939 }
2940 }
2941 });
2942 active_tooltip
2943 .borrow_mut()
2944 .replace(ActiveTooltip::WaitingForHide {
2945 tooltip,
2946 _task: delayed_hide_task,
2947 });
2948 }
2949 Action::CancelHide(tooltip) => {
2950 // Cancel waiting to hide tooltip when it becomes hovered.
2951 active_tooltip.borrow_mut().replace(ActiveTooltip::Visible {
2952 tooltip,
2953 is_hoverable: true,
2954 });
2955 }
2956 }
2957
2958 active_tooltip.borrow().is_some()
2959}
2960
2961#[derive(Default)]
2962pub(crate) struct GroupHitboxes(HashMap<SharedString, SmallVec<[HitboxId; 1]>>);
2963
2964impl Global for GroupHitboxes {}
2965
2966impl GroupHitboxes {
2967 pub fn get(name: &SharedString, cx: &mut App) -> Option<HitboxId> {
2968 cx.default_global::<Self>()
2969 .0
2970 .get(name)
2971 .and_then(|bounds_stack| bounds_stack.last())
2972 .cloned()
2973 }
2974
2975 pub fn push(name: SharedString, hitbox_id: HitboxId, cx: &mut App) {
2976 cx.default_global::<Self>()
2977 .0
2978 .entry(name)
2979 .or_default()
2980 .push(hitbox_id);
2981 }
2982
2983 pub fn pop(name: &SharedString, cx: &mut App) {
2984 cx.default_global::<Self>().0.get_mut(name).unwrap().pop();
2985 }
2986}
2987
2988/// A wrapper around an element that can store state, produced after assigning an ElementId.
2989pub struct Stateful<E> {
2990 pub(crate) element: E,
2991}
2992
2993impl<E> Styled for Stateful<E>
2994where
2995 E: Styled,
2996{
2997 fn style(&mut self) -> &mut StyleRefinement {
2998 self.element.style()
2999 }
3000}
3001
3002impl<E> StatefulInteractiveElement for Stateful<E>
3003where
3004 E: Element,
3005 Self: InteractiveElement,
3006{
3007}
3008
3009impl<E> InteractiveElement for Stateful<E>
3010where
3011 E: InteractiveElement,
3012{
3013 fn interactivity(&mut self) -> &mut Interactivity {
3014 self.element.interactivity()
3015 }
3016}
3017
3018impl<E> Element for Stateful<E>
3019where
3020 E: Element,
3021{
3022 type RequestLayoutState = E::RequestLayoutState;
3023 type PrepaintState = E::PrepaintState;
3024
3025 fn id(&self) -> Option<ElementId> {
3026 self.element.id()
3027 }
3028
3029 fn source_location(&self) -> Option<&'static core::panic::Location<'static>> {
3030 self.element.source_location()
3031 }
3032
3033 fn request_layout(
3034 &mut self,
3035 id: Option<&GlobalElementId>,
3036 inspector_id: Option<&InspectorElementId>,
3037 window: &mut Window,
3038 cx: &mut App,
3039 ) -> (LayoutId, Self::RequestLayoutState) {
3040 self.element.request_layout(id, inspector_id, window, cx)
3041 }
3042
3043 fn prepaint(
3044 &mut self,
3045 id: Option<&GlobalElementId>,
3046 inspector_id: Option<&InspectorElementId>,
3047 bounds: Bounds<Pixels>,
3048 state: &mut Self::RequestLayoutState,
3049 window: &mut Window,
3050 cx: &mut App,
3051 ) -> E::PrepaintState {
3052 self.element
3053 .prepaint(id, inspector_id, bounds, state, window, cx)
3054 }
3055
3056 fn paint(
3057 &mut self,
3058 id: Option<&GlobalElementId>,
3059 inspector_id: Option<&InspectorElementId>,
3060 bounds: Bounds<Pixels>,
3061 request_layout: &mut Self::RequestLayoutState,
3062 prepaint: &mut Self::PrepaintState,
3063 window: &mut Window,
3064 cx: &mut App,
3065 ) {
3066 self.element.paint(
3067 id,
3068 inspector_id,
3069 bounds,
3070 request_layout,
3071 prepaint,
3072 window,
3073 cx,
3074 );
3075 }
3076}
3077
3078impl<E> IntoElement for Stateful<E>
3079where
3080 E: Element,
3081{
3082 type Element = Self;
3083
3084 fn into_element(self) -> Self::Element {
3085 self
3086 }
3087}
3088
3089impl<E> ParentElement for Stateful<E>
3090where
3091 E: ParentElement,
3092{
3093 fn extend(&mut self, elements: impl IntoIterator<Item = AnyElement>) {
3094 self.element.extend(elements)
3095 }
3096}
3097
3098/// Represents an element that can be scrolled *to* in its parent element.
3099/// Contrary to [ScrollHandle::scroll_to_active_item], an anchored element does not have to be an immediate child of the parent.
3100#[derive(Clone)]
3101pub struct ScrollAnchor {
3102 handle: ScrollHandle,
3103 last_origin: Rc<RefCell<Point<Pixels>>>,
3104}
3105
3106impl ScrollAnchor {
3107 /// Creates a [ScrollAnchor] associated with a given [ScrollHandle].
3108 pub fn for_handle(handle: ScrollHandle) -> Self {
3109 Self {
3110 handle,
3111 last_origin: Default::default(),
3112 }
3113 }
3114 /// Request scroll to this item on the next frame.
3115 pub fn scroll_to(&self, window: &mut Window, _cx: &mut App) {
3116 let this = self.clone();
3117
3118 window.on_next_frame(move |_, _| {
3119 let viewport_bounds = this.handle.bounds();
3120 let self_bounds = *this.last_origin.borrow();
3121 this.handle.set_offset(viewport_bounds.origin - self_bounds);
3122 });
3123 }
3124}
3125
3126#[derive(Default, Debug)]
3127struct ScrollHandleState {
3128 offset: Rc<RefCell<Point<Pixels>>>,
3129 bounds: Bounds<Pixels>,
3130 max_offset: Size<Pixels>,
3131 child_bounds: Vec<Bounds<Pixels>>,
3132 scroll_to_bottom: bool,
3133 overflow: Point<Overflow>,
3134 active_item: Option<ScrollActiveItem>,
3135}
3136
3137#[derive(Default, Debug, Clone, Copy)]
3138struct ScrollActiveItem {
3139 index: usize,
3140 strategy: ScrollStrategy,
3141}
3142
3143#[derive(Default, Debug, Clone, Copy)]
3144enum ScrollStrategy {
3145 #[default]
3146 FirstVisible,
3147 Top,
3148}
3149
3150/// A handle to the scrollable aspects of an element.
3151/// Used for accessing scroll state, like the current scroll offset,
3152/// and for mutating the scroll state, like scrolling to a specific child.
3153#[derive(Clone, Debug)]
3154pub struct ScrollHandle(Rc<RefCell<ScrollHandleState>>);
3155
3156impl Default for ScrollHandle {
3157 fn default() -> Self {
3158 Self::new()
3159 }
3160}
3161
3162impl ScrollHandle {
3163 /// Construct a new scroll handle.
3164 pub fn new() -> Self {
3165 Self(Rc::default())
3166 }
3167
3168 /// Get the current scroll offset.
3169 pub fn offset(&self) -> Point<Pixels> {
3170 *self.0.borrow().offset.borrow()
3171 }
3172
3173 /// Get the maximum scroll offset.
3174 pub fn max_offset(&self) -> Size<Pixels> {
3175 self.0.borrow().max_offset
3176 }
3177
3178 /// Get the top child that's scrolled into view.
3179 pub fn top_item(&self) -> usize {
3180 let state = self.0.borrow();
3181 let top = state.bounds.top() - state.offset.borrow().y;
3182
3183 match state.child_bounds.binary_search_by(|bounds| {
3184 if top < bounds.top() {
3185 Ordering::Greater
3186 } else if top > bounds.bottom() {
3187 Ordering::Less
3188 } else {
3189 Ordering::Equal
3190 }
3191 }) {
3192 Ok(ix) => ix,
3193 Err(ix) => ix.min(state.child_bounds.len().saturating_sub(1)),
3194 }
3195 }
3196
3197 /// Get the bottom child that's scrolled into view.
3198 pub fn bottom_item(&self) -> usize {
3199 let state = self.0.borrow();
3200 let bottom = state.bounds.bottom() - state.offset.borrow().y;
3201
3202 match state.child_bounds.binary_search_by(|bounds| {
3203 if bottom < bounds.top() {
3204 Ordering::Greater
3205 } else if bottom > bounds.bottom() {
3206 Ordering::Less
3207 } else {
3208 Ordering::Equal
3209 }
3210 }) {
3211 Ok(ix) => ix,
3212 Err(ix) => ix.min(state.child_bounds.len().saturating_sub(1)),
3213 }
3214 }
3215
3216 /// Return the bounds into which this child is painted
3217 pub fn bounds(&self) -> Bounds<Pixels> {
3218 self.0.borrow().bounds
3219 }
3220
3221 /// Get the bounds for a specific child.
3222 pub fn bounds_for_item(&self, ix: usize) -> Option<Bounds<Pixels>> {
3223 self.0.borrow().child_bounds.get(ix).cloned()
3224 }
3225
3226 /// Update [ScrollHandleState]'s active item for scrolling to in prepaint
3227 pub fn scroll_to_item(&self, ix: usize) {
3228 let mut state = self.0.borrow_mut();
3229 state.active_item = Some(ScrollActiveItem {
3230 index: ix,
3231 strategy: ScrollStrategy::default(),
3232 });
3233 }
3234
3235 /// Update [ScrollHandleState]'s active item for scrolling to in prepaint
3236 /// This scrolls the minimal amount to ensure that the child is the first visible element
3237 pub fn scroll_to_top_of_item(&self, ix: usize) {
3238 let mut state = self.0.borrow_mut();
3239 state.active_item = Some(ScrollActiveItem {
3240 index: ix,
3241 strategy: ScrollStrategy::Top,
3242 });
3243 }
3244
3245 /// Scrolls the minimal amount to either ensure that the child is
3246 /// fully visible or the top element of the view depends on the
3247 /// scroll strategy
3248 fn scroll_to_active_item(&self) {
3249 let mut state = self.0.borrow_mut();
3250
3251 let Some(active_item) = state.active_item else {
3252 return;
3253 };
3254
3255 let active_item = match state.child_bounds.get(active_item.index) {
3256 Some(bounds) => {
3257 let mut scroll_offset = state.offset.borrow_mut();
3258
3259 match active_item.strategy {
3260 ScrollStrategy::FirstVisible => {
3261 if state.overflow.y == Overflow::Scroll {
3262 let child_height = bounds.size.height;
3263 let viewport_height = state.bounds.size.height;
3264 if child_height > viewport_height {
3265 scroll_offset.y = state.bounds.top() - bounds.top();
3266 } else if bounds.top() + scroll_offset.y < state.bounds.top() {
3267 scroll_offset.y = state.bounds.top() - bounds.top();
3268 } else if bounds.bottom() + scroll_offset.y > state.bounds.bottom() {
3269 scroll_offset.y = state.bounds.bottom() - bounds.bottom();
3270 }
3271 }
3272 }
3273 ScrollStrategy::Top => {
3274 scroll_offset.y = state.bounds.top() - bounds.top();
3275 }
3276 }
3277
3278 if state.overflow.x == Overflow::Scroll {
3279 let child_width = bounds.size.width;
3280 let viewport_width = state.bounds.size.width;
3281 if child_width > viewport_width {
3282 scroll_offset.x = state.bounds.left() - bounds.left();
3283 } else if bounds.left() + scroll_offset.x < state.bounds.left() {
3284 scroll_offset.x = state.bounds.left() - bounds.left();
3285 } else if bounds.right() + scroll_offset.x > state.bounds.right() {
3286 scroll_offset.x = state.bounds.right() - bounds.right();
3287 }
3288 }
3289 None
3290 }
3291 None => Some(active_item),
3292 };
3293 state.active_item = active_item;
3294 }
3295
3296 /// Scrolls to the bottom.
3297 pub fn scroll_to_bottom(&self) {
3298 let mut state = self.0.borrow_mut();
3299 state.scroll_to_bottom = true;
3300 }
3301
3302 /// Set the offset explicitly. The offset is the distance from the top left of the
3303 /// parent container to the top left of the first child.
3304 /// As you scroll further down the offset becomes more negative.
3305 pub fn set_offset(&self, mut position: Point<Pixels>) {
3306 let state = self.0.borrow();
3307 *state.offset.borrow_mut() = position;
3308 }
3309
3310 /// Get the logical scroll top, based on a child index and a pixel offset.
3311 pub fn logical_scroll_top(&self) -> (usize, Pixels) {
3312 let ix = self.top_item();
3313 let state = self.0.borrow();
3314
3315 if let Some(child_bounds) = state.child_bounds.get(ix) {
3316 (
3317 ix,
3318 child_bounds.top() + state.offset.borrow().y - state.bounds.top(),
3319 )
3320 } else {
3321 (ix, px(0.))
3322 }
3323 }
3324
3325 /// Get the logical scroll bottom, based on a child index and a pixel offset.
3326 pub fn logical_scroll_bottom(&self) -> (usize, Pixels) {
3327 let ix = self.bottom_item();
3328 let state = self.0.borrow();
3329
3330 if let Some(child_bounds) = state.child_bounds.get(ix) {
3331 (
3332 ix,
3333 child_bounds.bottom() + state.offset.borrow().y - state.bounds.bottom(),
3334 )
3335 } else {
3336 (ix, px(0.))
3337 }
3338 }
3339
3340 /// Get the count of children for scrollable item.
3341 pub fn children_count(&self) -> usize {
3342 self.0.borrow().child_bounds.len()
3343 }
3344}
3345
3346#[cfg(test)]
3347mod tests {
3348 use super::*;
3349
3350 #[test]
3351 fn scroll_handle_aligns_wide_children_to_left_edge() {
3352 let handle = ScrollHandle::new();
3353 {
3354 let mut state = handle.0.borrow_mut();
3355 state.bounds = Bounds::new(point(px(0.), px(0.)), size(px(80.), px(20.)));
3356 state.child_bounds = vec![Bounds::new(point(px(25.), px(0.)), size(px(200.), px(20.)))];
3357 state.overflow.x = Overflow::Scroll;
3358 state.active_item = Some(ScrollActiveItem {
3359 index: 0,
3360 strategy: ScrollStrategy::default(),
3361 });
3362 }
3363
3364 handle.scroll_to_active_item();
3365
3366 assert_eq!(handle.offset().x, px(-25.));
3367 }
3368
3369 #[test]
3370 fn scroll_handle_aligns_tall_children_to_top_edge() {
3371 let handle = ScrollHandle::new();
3372 {
3373 let mut state = handle.0.borrow_mut();
3374 state.bounds = Bounds::new(point(px(0.), px(0.)), size(px(20.), px(80.)));
3375 state.child_bounds = vec![Bounds::new(point(px(0.), px(25.)), size(px(20.), px(200.)))];
3376 state.overflow.y = Overflow::Scroll;
3377 state.active_item = Some(ScrollActiveItem {
3378 index: 0,
3379 strategy: ScrollStrategy::default(),
3380 });
3381 }
3382
3383 handle.scroll_to_active_item();
3384
3385 assert_eq!(handle.offset().y, px(-25.));
3386 }
3387}