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(cx)` 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 self.hover_style.is_some() || self.group_hover_style.is_some() {
1734 element_state
1735 .hover_state
1736 .get_or_insert_with(Default::default);
1737 }
1738 if let Some(active_tooltip) = element_state.active_tooltip.as_ref() {
1739 if self.tooltip_builder.is_some() {
1740 self.tooltip_id = set_tooltip_on_window(active_tooltip, window);
1741 } else {
1742 // If there is no longer a tooltip builder, remove the active tooltip.
1743 element_state.active_tooltip.take();
1744 }
1745 }
1746 }
1747
1748 window.with_text_style(style.text_style().cloned(), |window| {
1749 window.with_content_mask(
1750 style.overflow_mask(bounds, window.rem_size()),
1751 |window| {
1752 let hitbox = if self.should_insert_hitbox(&style, window, cx) {
1753 Some(window.insert_hitbox(bounds, self.hitbox_behavior))
1754 } else {
1755 None
1756 };
1757
1758 let scroll_offset =
1759 self.clamp_scroll_position(bounds, &style, window, cx);
1760 let result = f(&style, scroll_offset, hitbox, window, cx);
1761 (result, element_state)
1762 },
1763 )
1764 })
1765 },
1766 )
1767 }
1768
1769 fn should_insert_hitbox(&self, style: &Style, window: &Window, cx: &App) -> bool {
1770 self.hitbox_behavior != HitboxBehavior::Normal
1771 || self.window_control.is_some()
1772 || style.mouse_cursor.is_some()
1773 || self.group.is_some()
1774 || self.scroll_offset.is_some()
1775 || self.tracked_focus_handle.is_some()
1776 || self.hover_style.is_some()
1777 || self.group_hover_style.is_some()
1778 || self.hover_listener.is_some()
1779 || !self.mouse_up_listeners.is_empty()
1780 || !self.mouse_pressure_listeners.is_empty()
1781 || !self.mouse_down_listeners.is_empty()
1782 || !self.mouse_move_listeners.is_empty()
1783 || !self.click_listeners.is_empty()
1784 || !self.scroll_wheel_listeners.is_empty()
1785 || self.drag_listener.is_some()
1786 || !self.drop_listeners.is_empty()
1787 || self.tooltip_builder.is_some()
1788 || window.is_inspector_picking(cx)
1789 }
1790
1791 fn clamp_scroll_position(
1792 &self,
1793 bounds: Bounds<Pixels>,
1794 style: &Style,
1795 window: &mut Window,
1796 _cx: &mut App,
1797 ) -> Point<Pixels> {
1798 fn round_to_two_decimals(pixels: Pixels) -> Pixels {
1799 const ROUNDING_FACTOR: f32 = 100.0;
1800 (pixels * ROUNDING_FACTOR).round() / ROUNDING_FACTOR
1801 }
1802
1803 if let Some(scroll_offset) = self.scroll_offset.as_ref() {
1804 let mut scroll_to_bottom = false;
1805 let mut tracked_scroll_handle = self
1806 .tracked_scroll_handle
1807 .as_ref()
1808 .map(|handle| handle.0.borrow_mut());
1809 if let Some(mut scroll_handle_state) = tracked_scroll_handle.as_deref_mut() {
1810 scroll_handle_state.overflow = style.overflow;
1811 scroll_to_bottom = mem::take(&mut scroll_handle_state.scroll_to_bottom);
1812 }
1813
1814 let rem_size = window.rem_size();
1815 let padding = style.padding.to_pixels(bounds.size.into(), rem_size);
1816 let padding_size = size(padding.left + padding.right, padding.top + padding.bottom);
1817 // The floating point values produced by Taffy and ours often vary
1818 // slightly after ~5 decimal places. This can lead to cases where after
1819 // subtracting these, the container becomes scrollable for less than
1820 // 0.00000x pixels. As we generally don't benefit from a precision that
1821 // high for the maximum scroll, we round the scroll max to 2 decimal
1822 // places here.
1823 let padded_content_size = self.content_size + padding_size;
1824 let scroll_max = (padded_content_size - bounds.size)
1825 .map(round_to_two_decimals)
1826 .max(&Default::default());
1827 // Clamp scroll offset in case scroll max is smaller now (e.g., if children
1828 // were removed or the bounds became larger).
1829 let mut scroll_offset = scroll_offset.borrow_mut();
1830
1831 scroll_offset.x = scroll_offset.x.clamp(-scroll_max.width, px(0.));
1832 if scroll_to_bottom {
1833 scroll_offset.y = -scroll_max.height;
1834 } else {
1835 scroll_offset.y = scroll_offset.y.clamp(-scroll_max.height, px(0.));
1836 }
1837
1838 if let Some(mut scroll_handle_state) = tracked_scroll_handle {
1839 scroll_handle_state.max_offset = scroll_max;
1840 scroll_handle_state.bounds = bounds;
1841 }
1842
1843 *scroll_offset
1844 } else {
1845 Point::default()
1846 }
1847 }
1848
1849 /// Paint this element according to this interactivity state's configured styles
1850 /// and bind the element's mouse and keyboard events.
1851 ///
1852 /// content_size is the size of the content of the element, which may be larger than the
1853 /// element's bounds if the element is scrollable.
1854 ///
1855 /// the final computed style will be passed to the provided function, along
1856 /// with the current scroll offset
1857 pub fn paint(
1858 &mut self,
1859 global_id: Option<&GlobalElementId>,
1860 _inspector_id: Option<&InspectorElementId>,
1861 bounds: Bounds<Pixels>,
1862 hitbox: Option<&Hitbox>,
1863 window: &mut Window,
1864 cx: &mut App,
1865 f: impl FnOnce(&Style, &mut Window, &mut App),
1866 ) {
1867 self.hovered = hitbox.map(|hitbox| hitbox.is_hovered(window));
1868 window.with_optional_element_state::<InteractiveElementState, _>(
1869 global_id,
1870 |element_state, window| {
1871 let mut element_state =
1872 element_state.map(|element_state| element_state.unwrap_or_default());
1873
1874 let style = self.compute_style_internal(hitbox, element_state.as_mut(), window, cx);
1875
1876 #[cfg(any(feature = "test-support", test))]
1877 if let Some(debug_selector) = &self.debug_selector {
1878 window
1879 .next_frame
1880 .debug_bounds
1881 .insert(debug_selector.clone(), bounds);
1882 }
1883
1884 self.paint_hover_group_handler(window, cx);
1885
1886 if style.visibility == Visibility::Hidden {
1887 return ((), element_state);
1888 }
1889
1890 let mut tab_group = None;
1891 if self.tab_group {
1892 tab_group = self.tab_index;
1893 }
1894 if let Some(focus_handle) = &self.tracked_focus_handle {
1895 window.next_frame.tab_stops.insert(focus_handle);
1896 }
1897
1898 window.with_element_opacity(style.opacity, |window| {
1899 style.paint(bounds, window, cx, |window: &mut Window, cx: &mut App| {
1900 window.with_text_style(style.text_style().cloned(), |window| {
1901 window.with_content_mask(
1902 style.overflow_mask(bounds, window.rem_size()),
1903 |window| {
1904 window.with_tab_group(tab_group, |window| {
1905 if let Some(hitbox) = hitbox {
1906 #[cfg(debug_assertions)]
1907 self.paint_debug_info(
1908 global_id, hitbox, &style, window, cx,
1909 );
1910
1911 if let Some(drag) = cx.active_drag.as_ref() {
1912 if let Some(mouse_cursor) = drag.cursor_style {
1913 window.set_window_cursor_style(mouse_cursor);
1914 }
1915 } else {
1916 if let Some(mouse_cursor) = style.mouse_cursor {
1917 window.set_cursor_style(mouse_cursor, hitbox);
1918 }
1919 }
1920
1921 if let Some(group) = self.group.clone() {
1922 GroupHitboxes::push(group, hitbox.id, cx);
1923 }
1924
1925 if let Some(area) = self.window_control {
1926 window.insert_window_control_hitbox(
1927 area,
1928 hitbox.clone(),
1929 );
1930 }
1931
1932 self.paint_mouse_listeners(
1933 hitbox,
1934 element_state.as_mut(),
1935 window,
1936 cx,
1937 );
1938 self.paint_scroll_listener(hitbox, &style, window, cx);
1939 }
1940
1941 self.paint_keyboard_listeners(window, cx);
1942 f(&style, window, cx);
1943
1944 if let Some(_hitbox) = hitbox {
1945 #[cfg(any(feature = "inspector", debug_assertions))]
1946 window.insert_inspector_hitbox(
1947 _hitbox.id,
1948 _inspector_id,
1949 cx,
1950 );
1951
1952 if let Some(group) = self.group.as_ref() {
1953 GroupHitboxes::pop(group, cx);
1954 }
1955 }
1956 })
1957 },
1958 );
1959 });
1960 });
1961 });
1962
1963 ((), element_state)
1964 },
1965 );
1966 }
1967
1968 #[cfg(debug_assertions)]
1969 fn paint_debug_info(
1970 &self,
1971 global_id: Option<&GlobalElementId>,
1972 hitbox: &Hitbox,
1973 style: &Style,
1974 window: &mut Window,
1975 cx: &mut App,
1976 ) {
1977 use crate::{BorderStyle, TextAlign};
1978
1979 if global_id.is_some()
1980 && (style.debug || style.debug_below || cx.has_global::<crate::DebugBelow>())
1981 && hitbox.is_hovered(window)
1982 {
1983 const FONT_SIZE: crate::Pixels = crate::Pixels(10.);
1984 let element_id = format!("{:?}", global_id.unwrap());
1985 let str_len = element_id.len();
1986
1987 let render_debug_text = |window: &mut Window| {
1988 if let Some(text) = window
1989 .text_system()
1990 .shape_text(
1991 element_id.into(),
1992 FONT_SIZE,
1993 &[window.text_style().to_run(str_len)],
1994 None,
1995 None,
1996 )
1997 .ok()
1998 .and_then(|mut text| text.pop())
1999 {
2000 text.paint(hitbox.origin, FONT_SIZE, TextAlign::Left, None, window, cx)
2001 .ok();
2002
2003 let text_bounds = crate::Bounds {
2004 origin: hitbox.origin,
2005 size: text.size(FONT_SIZE),
2006 };
2007 if self.source_location.is_some()
2008 && text_bounds.contains(&window.mouse_position())
2009 && window.modifiers().secondary()
2010 {
2011 let secondary_held = window.modifiers().secondary();
2012 window.on_key_event({
2013 move |e: &crate::ModifiersChangedEvent, _phase, window, _cx| {
2014 if e.modifiers.secondary() != secondary_held
2015 && text_bounds.contains(&window.mouse_position())
2016 {
2017 window.refresh();
2018 }
2019 }
2020 });
2021
2022 let was_hovered = hitbox.is_hovered(window);
2023 let current_view = window.current_view();
2024 window.on_mouse_event({
2025 let hitbox = hitbox.clone();
2026 move |_: &MouseMoveEvent, phase, window, cx| {
2027 if phase == DispatchPhase::Capture {
2028 let hovered = hitbox.is_hovered(window);
2029 if hovered != was_hovered {
2030 cx.notify(current_view)
2031 }
2032 }
2033 }
2034 });
2035
2036 window.on_mouse_event({
2037 let hitbox = hitbox.clone();
2038 let location = self.source_location.unwrap();
2039 move |e: &crate::MouseDownEvent, phase, window, cx| {
2040 if text_bounds.contains(&e.position)
2041 && phase.capture()
2042 && hitbox.is_hovered(window)
2043 {
2044 cx.stop_propagation();
2045 let Ok(dir) = std::env::current_dir() else {
2046 return;
2047 };
2048
2049 eprintln!(
2050 "This element was created at:\n{}:{}:{}",
2051 dir.join(location.file()).to_string_lossy(),
2052 location.line(),
2053 location.column()
2054 );
2055 }
2056 }
2057 });
2058 window.paint_quad(crate::outline(
2059 crate::Bounds {
2060 origin: hitbox.origin
2061 + crate::point(crate::px(0.), FONT_SIZE - px(2.)),
2062 size: crate::Size {
2063 width: text_bounds.size.width,
2064 height: crate::px(1.),
2065 },
2066 },
2067 crate::red(),
2068 BorderStyle::default(),
2069 ))
2070 }
2071 }
2072 };
2073
2074 window.with_text_style(
2075 Some(crate::TextStyleRefinement {
2076 color: Some(crate::red()),
2077 line_height: Some(FONT_SIZE.into()),
2078 background_color: Some(crate::white()),
2079 ..Default::default()
2080 }),
2081 render_debug_text,
2082 )
2083 }
2084 }
2085
2086 fn paint_mouse_listeners(
2087 &mut self,
2088 hitbox: &Hitbox,
2089 element_state: Option<&mut InteractiveElementState>,
2090 window: &mut Window,
2091 cx: &mut App,
2092 ) {
2093 let is_focused = self
2094 .tracked_focus_handle
2095 .as_ref()
2096 .map(|handle| handle.is_focused(window))
2097 .unwrap_or(false);
2098
2099 // If this element can be focused, register a mouse down listener
2100 // that will automatically transfer focus when hitting the element.
2101 // This behavior can be suppressed by using `cx.prevent_default()`.
2102 if let Some(focus_handle) = self.tracked_focus_handle.clone() {
2103 let hitbox = hitbox.clone();
2104 window.on_mouse_event(move |_: &MouseDownEvent, phase, window, cx| {
2105 if phase == DispatchPhase::Bubble
2106 && hitbox.is_hovered(window)
2107 && !window.default_prevented()
2108 {
2109 window.focus(&focus_handle, cx);
2110 // If there is a parent that is also focusable, prevent it
2111 // from transferring focus because we already did so.
2112 window.prevent_default();
2113 }
2114 });
2115 }
2116
2117 for listener in self.mouse_down_listeners.drain(..) {
2118 let hitbox = hitbox.clone();
2119 window.on_mouse_event(move |event: &MouseDownEvent, phase, window, cx| {
2120 listener(event, phase, &hitbox, window, cx);
2121 })
2122 }
2123
2124 for listener in self.mouse_up_listeners.drain(..) {
2125 let hitbox = hitbox.clone();
2126 window.on_mouse_event(move |event: &MouseUpEvent, phase, window, cx| {
2127 listener(event, phase, &hitbox, window, cx);
2128 })
2129 }
2130
2131 for listener in self.mouse_pressure_listeners.drain(..) {
2132 let hitbox = hitbox.clone();
2133 window.on_mouse_event(move |event: &MousePressureEvent, phase, window, cx| {
2134 listener(event, phase, &hitbox, window, cx);
2135 })
2136 }
2137
2138 for listener in self.mouse_move_listeners.drain(..) {
2139 let hitbox = hitbox.clone();
2140 window.on_mouse_event(move |event: &MouseMoveEvent, phase, window, cx| {
2141 listener(event, phase, &hitbox, window, cx);
2142 })
2143 }
2144
2145 for listener in self.scroll_wheel_listeners.drain(..) {
2146 let hitbox = hitbox.clone();
2147 window.on_mouse_event(move |event: &ScrollWheelEvent, phase, window, cx| {
2148 listener(event, phase, &hitbox, window, cx);
2149 })
2150 }
2151
2152 if self.hover_style.is_some()
2153 || self.base_style.mouse_cursor.is_some()
2154 || cx.active_drag.is_some() && !self.drag_over_styles.is_empty()
2155 {
2156 let hitbox = hitbox.clone();
2157 let was_hovered = hitbox.is_hovered(window);
2158 let hover_state = self.hover_style.as_ref().and_then(|_| {
2159 element_state
2160 .as_ref()
2161 .and_then(|state| state.hover_state.as_ref())
2162 .cloned()
2163 });
2164 let current_view = window.current_view();
2165 window.on_mouse_event(move |_: &MouseMoveEvent, phase, window, cx| {
2166 let hovered = hitbox.is_hovered(window);
2167 if phase == DispatchPhase::Capture && hovered != was_hovered {
2168 if let Some(hover_state) = &hover_state {
2169 hover_state.borrow_mut().element = hovered;
2170 }
2171 cx.notify(current_view);
2172 }
2173 });
2174 }
2175
2176 if let Some(group_hover) = self.group_hover_style.as_ref() {
2177 if let Some(group_hitbox_id) = GroupHitboxes::get(&group_hover.group, cx) {
2178 let hover_state = element_state
2179 .as_ref()
2180 .and_then(|element| element.hover_state.as_ref())
2181 .cloned();
2182
2183 let was_group_hovered = group_hitbox_id.is_hovered(window);
2184 let current_view = window.current_view();
2185
2186 window.on_mouse_event(move |_: &MouseMoveEvent, phase, window, cx| {
2187 let group_hovered = group_hitbox_id.is_hovered(window);
2188 if phase == DispatchPhase::Capture && group_hovered != was_group_hovered {
2189 if let Some(hover_state) = &hover_state {
2190 hover_state.borrow_mut().group = group_hovered;
2191 }
2192 cx.notify(current_view);
2193 }
2194 });
2195 }
2196 }
2197
2198 let drag_cursor_style = self.base_style.as_ref().mouse_cursor;
2199
2200 let mut drag_listener = mem::take(&mut self.drag_listener);
2201 let drop_listeners = mem::take(&mut self.drop_listeners);
2202 let click_listeners = mem::take(&mut self.click_listeners);
2203 let can_drop_predicate = mem::take(&mut self.can_drop_predicate);
2204
2205 if !drop_listeners.is_empty() {
2206 let hitbox = hitbox.clone();
2207 window.on_mouse_event({
2208 move |_: &MouseUpEvent, phase, window, cx| {
2209 if let Some(drag) = &cx.active_drag
2210 && phase == DispatchPhase::Bubble
2211 && hitbox.is_hovered(window)
2212 {
2213 let drag_state_type = drag.value.as_ref().type_id();
2214 for (drop_state_type, listener) in &drop_listeners {
2215 if *drop_state_type == drag_state_type {
2216 let drag = cx
2217 .active_drag
2218 .take()
2219 .expect("checked for type drag state type above");
2220
2221 let mut can_drop = true;
2222 if let Some(predicate) = &can_drop_predicate {
2223 can_drop = predicate(drag.value.as_ref(), window, cx);
2224 }
2225
2226 if can_drop {
2227 listener(drag.value.as_ref(), window, cx);
2228 window.refresh();
2229 cx.stop_propagation();
2230 }
2231 }
2232 }
2233 }
2234 }
2235 });
2236 }
2237
2238 if let Some(element_state) = element_state {
2239 if !click_listeners.is_empty() || drag_listener.is_some() {
2240 let pending_mouse_down = element_state
2241 .pending_mouse_down
2242 .get_or_insert_with(Default::default)
2243 .clone();
2244
2245 let clicked_state = element_state
2246 .clicked_state
2247 .get_or_insert_with(Default::default)
2248 .clone();
2249
2250 window.on_mouse_event({
2251 let pending_mouse_down = pending_mouse_down.clone();
2252 let hitbox = hitbox.clone();
2253 move |event: &MouseDownEvent, phase, window, _cx| {
2254 if phase == DispatchPhase::Bubble
2255 && event.button == MouseButton::Left
2256 && hitbox.is_hovered(window)
2257 {
2258 *pending_mouse_down.borrow_mut() = Some(event.clone());
2259 window.refresh();
2260 }
2261 }
2262 });
2263
2264 window.on_mouse_event({
2265 let pending_mouse_down = pending_mouse_down.clone();
2266 let hitbox = hitbox.clone();
2267 move |event: &MouseMoveEvent, phase, window, cx| {
2268 if phase == DispatchPhase::Capture {
2269 return;
2270 }
2271
2272 let mut pending_mouse_down = pending_mouse_down.borrow_mut();
2273 if let Some(mouse_down) = pending_mouse_down.clone()
2274 && !cx.has_active_drag()
2275 && (event.position - mouse_down.position).magnitude() > DRAG_THRESHOLD
2276 && let Some((drag_value, drag_listener)) = drag_listener.take()
2277 {
2278 *clicked_state.borrow_mut() = ElementClickedState::default();
2279 let cursor_offset = event.position - hitbox.origin;
2280 let drag =
2281 (drag_listener)(drag_value.as_ref(), cursor_offset, window, cx);
2282 cx.active_drag = Some(AnyDrag {
2283 view: drag,
2284 value: drag_value,
2285 cursor_offset,
2286 cursor_style: drag_cursor_style,
2287 });
2288 pending_mouse_down.take();
2289 window.refresh();
2290 cx.stop_propagation();
2291 }
2292 }
2293 });
2294
2295 if is_focused {
2296 // Press enter, space to trigger click, when the element is focused.
2297 window.on_key_event({
2298 let click_listeners = click_listeners.clone();
2299 let hitbox = hitbox.clone();
2300 move |event: &KeyUpEvent, phase, window, cx| {
2301 if phase.bubble() && !window.default_prevented() {
2302 let stroke = &event.keystroke;
2303 let keyboard_button = if stroke.key.eq("enter") {
2304 Some(KeyboardButton::Enter)
2305 } else if stroke.key.eq("space") {
2306 Some(KeyboardButton::Space)
2307 } else {
2308 None
2309 };
2310
2311 if let Some(button) = keyboard_button
2312 && !stroke.modifiers.modified()
2313 {
2314 let click_event = ClickEvent::Keyboard(KeyboardClickEvent {
2315 button,
2316 bounds: hitbox.bounds,
2317 });
2318
2319 for listener in &click_listeners {
2320 listener(&click_event, window, cx);
2321 }
2322 }
2323 }
2324 }
2325 });
2326 }
2327
2328 window.on_mouse_event({
2329 let mut captured_mouse_down = None;
2330 let hitbox = hitbox.clone();
2331 move |event: &MouseUpEvent, phase, window, cx| match phase {
2332 // Clear the pending mouse down during the capture phase,
2333 // so that it happens even if another event handler stops
2334 // propagation.
2335 DispatchPhase::Capture => {
2336 let mut pending_mouse_down = pending_mouse_down.borrow_mut();
2337 if pending_mouse_down.is_some() && hitbox.is_hovered(window) {
2338 captured_mouse_down = pending_mouse_down.take();
2339 window.refresh();
2340 } else if pending_mouse_down.is_some() {
2341 // Clear the pending mouse down event (without firing click handlers)
2342 // if the hitbox is not being hovered.
2343 // This avoids dragging elements that changed their position
2344 // immediately after being clicked.
2345 // See https://github.com/zed-industries/zed/issues/24600 for more details
2346 pending_mouse_down.take();
2347 window.refresh();
2348 }
2349 }
2350 // Fire click handlers during the bubble phase.
2351 DispatchPhase::Bubble => {
2352 if let Some(mouse_down) = captured_mouse_down.take() {
2353 let mouse_click = ClickEvent::Mouse(MouseClickEvent {
2354 down: mouse_down,
2355 up: event.clone(),
2356 });
2357 for listener in &click_listeners {
2358 listener(&mouse_click, window, cx);
2359 }
2360 }
2361 }
2362 }
2363 });
2364 }
2365
2366 if let Some(hover_listener) = self.hover_listener.take() {
2367 let hitbox = hitbox.clone();
2368 let was_hovered = element_state
2369 .hover_state
2370 .get_or_insert_with(Default::default)
2371 .clone();
2372 let has_mouse_down = element_state
2373 .pending_mouse_down
2374 .get_or_insert_with(Default::default)
2375 .clone();
2376
2377 window.on_mouse_event(move |_: &MouseMoveEvent, phase, window, cx| {
2378 if phase != DispatchPhase::Bubble {
2379 return;
2380 }
2381 let is_hovered = has_mouse_down.borrow().is_none()
2382 && !cx.has_active_drag()
2383 && hitbox.is_hovered(window);
2384 let mut was_hovered = was_hovered.borrow_mut();
2385
2386 if is_hovered != was_hovered.element {
2387 was_hovered.element = is_hovered;
2388 drop(was_hovered);
2389
2390 hover_listener(&is_hovered, window, cx);
2391 }
2392 });
2393 }
2394
2395 if let Some(tooltip_builder) = self.tooltip_builder.take() {
2396 let active_tooltip = element_state
2397 .active_tooltip
2398 .get_or_insert_with(Default::default)
2399 .clone();
2400 let pending_mouse_down = element_state
2401 .pending_mouse_down
2402 .get_or_insert_with(Default::default)
2403 .clone();
2404
2405 let tooltip_is_hoverable = tooltip_builder.hoverable;
2406 let build_tooltip = Rc::new(move |window: &mut Window, cx: &mut App| {
2407 Some(((tooltip_builder.build)(window, cx), tooltip_is_hoverable))
2408 });
2409 // Use bounds instead of testing hitbox since this is called during prepaint.
2410 let check_is_hovered_during_prepaint = Rc::new({
2411 let pending_mouse_down = pending_mouse_down.clone();
2412 let source_bounds = hitbox.bounds;
2413 move |window: &Window| {
2414 pending_mouse_down.borrow().is_none()
2415 && source_bounds.contains(&window.mouse_position())
2416 }
2417 });
2418 let check_is_hovered = Rc::new({
2419 let hitbox = hitbox.clone();
2420 move |window: &Window| {
2421 pending_mouse_down.borrow().is_none() && hitbox.is_hovered(window)
2422 }
2423 });
2424 register_tooltip_mouse_handlers(
2425 &active_tooltip,
2426 self.tooltip_id,
2427 build_tooltip,
2428 check_is_hovered,
2429 check_is_hovered_during_prepaint,
2430 window,
2431 );
2432 }
2433
2434 let active_state = element_state
2435 .clicked_state
2436 .get_or_insert_with(Default::default)
2437 .clone();
2438 if active_state.borrow().is_clicked() {
2439 window.on_mouse_event(move |_: &MouseUpEvent, phase, window, _cx| {
2440 if phase == DispatchPhase::Capture {
2441 *active_state.borrow_mut() = ElementClickedState::default();
2442 window.refresh();
2443 }
2444 });
2445 } else {
2446 let active_group_hitbox = self
2447 .group_active_style
2448 .as_ref()
2449 .and_then(|group_active| GroupHitboxes::get(&group_active.group, cx));
2450 let hitbox = hitbox.clone();
2451 window.on_mouse_event(move |_: &MouseDownEvent, phase, window, _cx| {
2452 if phase == DispatchPhase::Bubble && !window.default_prevented() {
2453 let group_hovered = active_group_hitbox
2454 .is_some_and(|group_hitbox_id| group_hitbox_id.is_hovered(window));
2455 let element_hovered = hitbox.is_hovered(window);
2456 if group_hovered || element_hovered {
2457 *active_state.borrow_mut() = ElementClickedState {
2458 group: group_hovered,
2459 element: element_hovered,
2460 };
2461 window.refresh();
2462 }
2463 }
2464 });
2465 }
2466 }
2467 }
2468
2469 fn paint_keyboard_listeners(&mut self, window: &mut Window, _cx: &mut App) {
2470 let key_down_listeners = mem::take(&mut self.key_down_listeners);
2471 let key_up_listeners = mem::take(&mut self.key_up_listeners);
2472 let modifiers_changed_listeners = mem::take(&mut self.modifiers_changed_listeners);
2473 let action_listeners = mem::take(&mut self.action_listeners);
2474 if let Some(context) = self.key_context.clone() {
2475 window.set_key_context(context);
2476 }
2477
2478 for listener in key_down_listeners {
2479 window.on_key_event(move |event: &KeyDownEvent, phase, window, cx| {
2480 listener(event, phase, window, cx);
2481 })
2482 }
2483
2484 for listener in key_up_listeners {
2485 window.on_key_event(move |event: &KeyUpEvent, phase, window, cx| {
2486 listener(event, phase, window, cx);
2487 })
2488 }
2489
2490 for listener in modifiers_changed_listeners {
2491 window.on_modifiers_changed(move |event: &ModifiersChangedEvent, window, cx| {
2492 listener(event, window, cx);
2493 })
2494 }
2495
2496 for (action_type, listener) in action_listeners {
2497 window.on_action(action_type, listener)
2498 }
2499 }
2500
2501 fn paint_hover_group_handler(&self, window: &mut Window, cx: &mut App) {
2502 let group_hitbox = self
2503 .group_hover_style
2504 .as_ref()
2505 .and_then(|group_hover| GroupHitboxes::get(&group_hover.group, cx));
2506
2507 if let Some(group_hitbox) = group_hitbox {
2508 let was_hovered = group_hitbox.is_hovered(window);
2509 let current_view = window.current_view();
2510 window.on_mouse_event(move |_: &MouseMoveEvent, phase, window, cx| {
2511 let hovered = group_hitbox.is_hovered(window);
2512 if phase == DispatchPhase::Capture && hovered != was_hovered {
2513 cx.notify(current_view);
2514 }
2515 });
2516 }
2517 }
2518
2519 fn paint_scroll_listener(
2520 &self,
2521 hitbox: &Hitbox,
2522 style: &Style,
2523 window: &mut Window,
2524 _cx: &mut App,
2525 ) {
2526 if let Some(scroll_offset) = self.scroll_offset.clone() {
2527 let overflow = style.overflow;
2528 let allow_concurrent_scroll = style.allow_concurrent_scroll;
2529 let restrict_scroll_to_axis = style.restrict_scroll_to_axis;
2530 let line_height = window.line_height();
2531 let hitbox = hitbox.clone();
2532 let current_view = window.current_view();
2533 window.on_mouse_event(move |event: &ScrollWheelEvent, phase, window, cx| {
2534 if phase == DispatchPhase::Bubble && hitbox.should_handle_scroll(window) {
2535 let mut scroll_offset = scroll_offset.borrow_mut();
2536 let old_scroll_offset = *scroll_offset;
2537 let delta = event.delta.pixel_delta(line_height);
2538
2539 let mut delta_x = Pixels::ZERO;
2540 if overflow.x == Overflow::Scroll {
2541 if !delta.x.is_zero() {
2542 delta_x = delta.x;
2543 } else if !restrict_scroll_to_axis && overflow.y != Overflow::Scroll {
2544 delta_x = delta.y;
2545 }
2546 }
2547 let mut delta_y = Pixels::ZERO;
2548 if overflow.y == Overflow::Scroll {
2549 if !delta.y.is_zero() {
2550 delta_y = delta.y;
2551 } else if !restrict_scroll_to_axis && overflow.x != Overflow::Scroll {
2552 delta_y = delta.x;
2553 }
2554 }
2555 if !allow_concurrent_scroll && !delta_x.is_zero() && !delta_y.is_zero() {
2556 if delta_x.abs() > delta_y.abs() {
2557 delta_y = Pixels::ZERO;
2558 } else {
2559 delta_x = Pixels::ZERO;
2560 }
2561 }
2562 scroll_offset.y += delta_y;
2563 scroll_offset.x += delta_x;
2564 if *scroll_offset != old_scroll_offset {
2565 cx.notify(current_view);
2566 }
2567 }
2568 });
2569 }
2570 }
2571
2572 /// Compute the visual style for this element, based on the current bounds and the element's state.
2573 pub fn compute_style(
2574 &self,
2575 global_id: Option<&GlobalElementId>,
2576 hitbox: Option<&Hitbox>,
2577 window: &mut Window,
2578 cx: &mut App,
2579 ) -> Style {
2580 window.with_optional_element_state(global_id, |element_state, window| {
2581 let mut element_state =
2582 element_state.map(|element_state| element_state.unwrap_or_default());
2583 let style = self.compute_style_internal(hitbox, element_state.as_mut(), window, cx);
2584 (style, element_state)
2585 })
2586 }
2587
2588 /// Called from internal methods that have already called with_element_state.
2589 fn compute_style_internal(
2590 &self,
2591 hitbox: Option<&Hitbox>,
2592 element_state: Option<&mut InteractiveElementState>,
2593 window: &mut Window,
2594 cx: &mut App,
2595 ) -> Style {
2596 let mut style = Style::default();
2597 style.refine(&self.base_style);
2598
2599 if let Some(focus_handle) = self.tracked_focus_handle.as_ref() {
2600 if let Some(in_focus_style) = self.in_focus_style.as_ref()
2601 && focus_handle.within_focused(window, cx)
2602 {
2603 style.refine(in_focus_style);
2604 }
2605
2606 if let Some(focus_style) = self.focus_style.as_ref()
2607 && focus_handle.is_focused(window)
2608 {
2609 style.refine(focus_style);
2610 }
2611
2612 if let Some(focus_visible_style) = self.focus_visible_style.as_ref()
2613 && focus_handle.is_focused(window)
2614 && window.last_input_was_keyboard()
2615 {
2616 style.refine(focus_visible_style);
2617 }
2618 }
2619
2620 if !cx.has_active_drag() {
2621 if let Some(group_hover) = self.group_hover_style.as_ref() {
2622 let is_group_hovered =
2623 if let Some(group_hitbox_id) = GroupHitboxes::get(&group_hover.group, cx) {
2624 group_hitbox_id.is_hovered(window)
2625 } else if let Some(element_state) = element_state.as_ref() {
2626 element_state
2627 .hover_state
2628 .as_ref()
2629 .map(|state| state.borrow().group)
2630 .unwrap_or(false)
2631 } else {
2632 false
2633 };
2634
2635 if is_group_hovered {
2636 style.refine(&group_hover.style);
2637 }
2638 }
2639
2640 if let Some(hover_style) = self.hover_style.as_ref() {
2641 let is_hovered = if let Some(hitbox) = hitbox {
2642 hitbox.is_hovered(window)
2643 } else if let Some(element_state) = element_state.as_ref() {
2644 element_state
2645 .hover_state
2646 .as_ref()
2647 .map(|state| state.borrow().element)
2648 .unwrap_or(false)
2649 } else {
2650 false
2651 };
2652
2653 if is_hovered {
2654 style.refine(hover_style);
2655 }
2656 }
2657 }
2658
2659 if let Some(hitbox) = hitbox {
2660 if let Some(drag) = cx.active_drag.take() {
2661 let mut can_drop = true;
2662 if let Some(can_drop_predicate) = &self.can_drop_predicate {
2663 can_drop = can_drop_predicate(drag.value.as_ref(), window, cx);
2664 }
2665
2666 if can_drop {
2667 for (state_type, group_drag_style) in &self.group_drag_over_styles {
2668 if let Some(group_hitbox_id) =
2669 GroupHitboxes::get(&group_drag_style.group, cx)
2670 && *state_type == drag.value.as_ref().type_id()
2671 && group_hitbox_id.is_hovered(window)
2672 {
2673 style.refine(&group_drag_style.style);
2674 }
2675 }
2676
2677 for (state_type, build_drag_over_style) in &self.drag_over_styles {
2678 if *state_type == drag.value.as_ref().type_id() && hitbox.is_hovered(window)
2679 {
2680 style.refine(&build_drag_over_style(drag.value.as_ref(), window, cx));
2681 }
2682 }
2683 }
2684
2685 style.mouse_cursor = drag.cursor_style;
2686 cx.active_drag = Some(drag);
2687 }
2688 }
2689
2690 if let Some(element_state) = element_state {
2691 let clicked_state = element_state
2692 .clicked_state
2693 .get_or_insert_with(Default::default)
2694 .borrow();
2695 if clicked_state.group
2696 && let Some(group) = self.group_active_style.as_ref()
2697 {
2698 style.refine(&group.style)
2699 }
2700
2701 if let Some(active_style) = self.active_style.as_ref()
2702 && clicked_state.element
2703 {
2704 style.refine(active_style)
2705 }
2706 }
2707
2708 style
2709 }
2710}
2711
2712/// The per-frame state of an interactive element. Used for tracking stateful interactions like clicks
2713/// and scroll offsets.
2714#[derive(Default)]
2715pub struct InteractiveElementState {
2716 pub(crate) focus_handle: Option<FocusHandle>,
2717 pub(crate) clicked_state: Option<Rc<RefCell<ElementClickedState>>>,
2718 pub(crate) hover_state: Option<Rc<RefCell<ElementHoverState>>>,
2719 pub(crate) pending_mouse_down: Option<Rc<RefCell<Option<MouseDownEvent>>>>,
2720 pub(crate) scroll_offset: Option<Rc<RefCell<Point<Pixels>>>>,
2721 pub(crate) active_tooltip: Option<Rc<RefCell<Option<ActiveTooltip>>>>,
2722}
2723
2724/// Whether or not the element or a group that contains it is clicked by the mouse.
2725#[derive(Copy, Clone, Default, Eq, PartialEq)]
2726pub struct ElementClickedState {
2727 /// True if this element's group has been clicked, false otherwise
2728 pub group: bool,
2729
2730 /// True if this element has been clicked, false otherwise
2731 pub element: bool,
2732}
2733
2734impl ElementClickedState {
2735 fn is_clicked(&self) -> bool {
2736 self.group || self.element
2737 }
2738}
2739
2740/// Whether or not the element or a group that contains it is hovered.
2741#[derive(Copy, Clone, Default, Eq, PartialEq)]
2742pub struct ElementHoverState {
2743 /// True if this element's group is hovered, false otherwise
2744 pub group: bool,
2745
2746 /// True if this element is hovered, false otherwise
2747 pub element: bool,
2748}
2749
2750pub(crate) enum ActiveTooltip {
2751 /// Currently delaying before showing the tooltip.
2752 WaitingForShow { _task: Task<()> },
2753 /// Tooltip is visible, element was hovered or for hoverable tooltips, the tooltip was hovered.
2754 Visible {
2755 tooltip: AnyTooltip,
2756 is_hoverable: bool,
2757 },
2758 /// Tooltip is visible and hoverable, but the mouse is no longer hovering. Currently delaying
2759 /// before hiding it.
2760 WaitingForHide {
2761 tooltip: AnyTooltip,
2762 _task: Task<()>,
2763 },
2764}
2765
2766pub(crate) fn clear_active_tooltip(
2767 active_tooltip: &Rc<RefCell<Option<ActiveTooltip>>>,
2768 window: &mut Window,
2769) {
2770 match active_tooltip.borrow_mut().take() {
2771 None => {}
2772 Some(ActiveTooltip::WaitingForShow { .. }) => {}
2773 Some(ActiveTooltip::Visible { .. }) => window.refresh(),
2774 Some(ActiveTooltip::WaitingForHide { .. }) => window.refresh(),
2775 }
2776}
2777
2778pub(crate) fn clear_active_tooltip_if_not_hoverable(
2779 active_tooltip: &Rc<RefCell<Option<ActiveTooltip>>>,
2780 window: &mut Window,
2781) {
2782 let should_clear = match active_tooltip.borrow().as_ref() {
2783 None => false,
2784 Some(ActiveTooltip::WaitingForShow { .. }) => false,
2785 Some(ActiveTooltip::Visible { is_hoverable, .. }) => !is_hoverable,
2786 Some(ActiveTooltip::WaitingForHide { .. }) => false,
2787 };
2788 if should_clear {
2789 active_tooltip.borrow_mut().take();
2790 window.refresh();
2791 }
2792}
2793
2794pub(crate) fn set_tooltip_on_window(
2795 active_tooltip: &Rc<RefCell<Option<ActiveTooltip>>>,
2796 window: &mut Window,
2797) -> Option<TooltipId> {
2798 let tooltip = match active_tooltip.borrow().as_ref() {
2799 None => return None,
2800 Some(ActiveTooltip::WaitingForShow { .. }) => return None,
2801 Some(ActiveTooltip::Visible { tooltip, .. }) => tooltip.clone(),
2802 Some(ActiveTooltip::WaitingForHide { tooltip, .. }) => tooltip.clone(),
2803 };
2804 Some(window.set_tooltip(tooltip))
2805}
2806
2807pub(crate) fn register_tooltip_mouse_handlers(
2808 active_tooltip: &Rc<RefCell<Option<ActiveTooltip>>>,
2809 tooltip_id: Option<TooltipId>,
2810 build_tooltip: Rc<dyn Fn(&mut Window, &mut App) -> Option<(AnyView, bool)>>,
2811 check_is_hovered: Rc<dyn Fn(&Window) -> bool>,
2812 check_is_hovered_during_prepaint: Rc<dyn Fn(&Window) -> bool>,
2813 window: &mut Window,
2814) {
2815 window.on_mouse_event({
2816 let active_tooltip = active_tooltip.clone();
2817 let build_tooltip = build_tooltip.clone();
2818 let check_is_hovered = check_is_hovered.clone();
2819 move |_: &MouseMoveEvent, phase, window, cx| {
2820 handle_tooltip_mouse_move(
2821 &active_tooltip,
2822 &build_tooltip,
2823 &check_is_hovered,
2824 &check_is_hovered_during_prepaint,
2825 phase,
2826 window,
2827 cx,
2828 )
2829 }
2830 });
2831
2832 window.on_mouse_event({
2833 let active_tooltip = active_tooltip.clone();
2834 move |_: &MouseDownEvent, _phase, window: &mut Window, _cx| {
2835 if !tooltip_id.is_some_and(|tooltip_id| tooltip_id.is_hovered(window)) {
2836 clear_active_tooltip_if_not_hoverable(&active_tooltip, window);
2837 }
2838 }
2839 });
2840
2841 window.on_mouse_event({
2842 let active_tooltip = active_tooltip.clone();
2843 move |_: &ScrollWheelEvent, _phase, window: &mut Window, _cx| {
2844 if !tooltip_id.is_some_and(|tooltip_id| tooltip_id.is_hovered(window)) {
2845 clear_active_tooltip_if_not_hoverable(&active_tooltip, window);
2846 }
2847 }
2848 });
2849}
2850
2851/// Handles displaying tooltips when an element is hovered.
2852///
2853/// The mouse hovering logic also relies on being called from window prepaint in order to handle the
2854/// case where the element the tooltip is on is not rendered - in that case its mouse listeners are
2855/// also not registered. During window prepaint, the hitbox information is not available, so
2856/// `check_is_hovered_during_prepaint` is used which bases the check off of the absolute bounds of
2857/// the element.
2858///
2859/// TODO: There's a minor bug due to the use of absolute bounds while checking during prepaint - it
2860/// does not know if the hitbox is occluded. In the case where a tooltip gets displayed and then
2861/// gets occluded after display, it will stick around until the mouse exits the hover bounds.
2862fn handle_tooltip_mouse_move(
2863 active_tooltip: &Rc<RefCell<Option<ActiveTooltip>>>,
2864 build_tooltip: &Rc<dyn Fn(&mut Window, &mut App) -> Option<(AnyView, bool)>>,
2865 check_is_hovered: &Rc<dyn Fn(&Window) -> bool>,
2866 check_is_hovered_during_prepaint: &Rc<dyn Fn(&Window) -> bool>,
2867 phase: DispatchPhase,
2868 window: &mut Window,
2869 cx: &mut App,
2870) {
2871 // Separates logic for what mutation should occur from applying it, to avoid overlapping
2872 // RefCell borrows.
2873 enum Action {
2874 None,
2875 CancelShow,
2876 ScheduleShow,
2877 }
2878
2879 let action = match active_tooltip.borrow().as_ref() {
2880 None => {
2881 let is_hovered = check_is_hovered(window);
2882 if is_hovered && phase.bubble() {
2883 Action::ScheduleShow
2884 } else {
2885 Action::None
2886 }
2887 }
2888 Some(ActiveTooltip::WaitingForShow { .. }) => {
2889 let is_hovered = check_is_hovered(window);
2890 if is_hovered {
2891 Action::None
2892 } else {
2893 Action::CancelShow
2894 }
2895 }
2896 // These are handled in check_visible_and_update.
2897 Some(ActiveTooltip::Visible { .. }) | Some(ActiveTooltip::WaitingForHide { .. }) => {
2898 Action::None
2899 }
2900 };
2901
2902 match action {
2903 Action::None => {}
2904 Action::CancelShow => {
2905 // Cancel waiting to show tooltip when it is no longer hovered.
2906 active_tooltip.borrow_mut().take();
2907 }
2908 Action::ScheduleShow => {
2909 let delayed_show_task = window.spawn(cx, {
2910 let active_tooltip = active_tooltip.clone();
2911 let build_tooltip = build_tooltip.clone();
2912 let check_is_hovered_during_prepaint = check_is_hovered_during_prepaint.clone();
2913 async move |cx| {
2914 cx.background_executor().timer(TOOLTIP_SHOW_DELAY).await;
2915 cx.update(|window, cx| {
2916 let new_tooltip =
2917 build_tooltip(window, cx).map(|(view, tooltip_is_hoverable)| {
2918 let active_tooltip = active_tooltip.clone();
2919 ActiveTooltip::Visible {
2920 tooltip: AnyTooltip {
2921 view,
2922 mouse_position: window.mouse_position(),
2923 check_visible_and_update: Rc::new(
2924 move |tooltip_bounds, window, cx| {
2925 handle_tooltip_check_visible_and_update(
2926 &active_tooltip,
2927 tooltip_is_hoverable,
2928 &check_is_hovered_during_prepaint,
2929 tooltip_bounds,
2930 window,
2931 cx,
2932 )
2933 },
2934 ),
2935 },
2936 is_hoverable: tooltip_is_hoverable,
2937 }
2938 });
2939 *active_tooltip.borrow_mut() = new_tooltip;
2940 window.refresh();
2941 })
2942 .ok();
2943 }
2944 });
2945 active_tooltip
2946 .borrow_mut()
2947 .replace(ActiveTooltip::WaitingForShow {
2948 _task: delayed_show_task,
2949 });
2950 }
2951 }
2952}
2953
2954/// Returns a callback which will be called by window prepaint to update tooltip visibility. The
2955/// purpose of doing this logic here instead of the mouse move handler is that the mouse move
2956/// handler won't get called when the element is not painted (e.g. via use of `visible_on_hover`).
2957fn handle_tooltip_check_visible_and_update(
2958 active_tooltip: &Rc<RefCell<Option<ActiveTooltip>>>,
2959 tooltip_is_hoverable: bool,
2960 check_is_hovered: &Rc<dyn Fn(&Window) -> bool>,
2961 tooltip_bounds: Bounds<Pixels>,
2962 window: &mut Window,
2963 cx: &mut App,
2964) -> bool {
2965 // Separates logic for what mutation should occur from applying it, to avoid overlapping RefCell
2966 // borrows.
2967 enum Action {
2968 None,
2969 Hide,
2970 ScheduleHide(AnyTooltip),
2971 CancelHide(AnyTooltip),
2972 }
2973
2974 let is_hovered = check_is_hovered(window)
2975 || (tooltip_is_hoverable && tooltip_bounds.contains(&window.mouse_position()));
2976 let action = match active_tooltip.borrow().as_ref() {
2977 Some(ActiveTooltip::Visible { tooltip, .. }) => {
2978 if is_hovered {
2979 Action::None
2980 } else {
2981 if tooltip_is_hoverable {
2982 Action::ScheduleHide(tooltip.clone())
2983 } else {
2984 Action::Hide
2985 }
2986 }
2987 }
2988 Some(ActiveTooltip::WaitingForHide { tooltip, .. }) => {
2989 if is_hovered {
2990 Action::CancelHide(tooltip.clone())
2991 } else {
2992 Action::None
2993 }
2994 }
2995 None | Some(ActiveTooltip::WaitingForShow { .. }) => Action::None,
2996 };
2997
2998 match action {
2999 Action::None => {}
3000 Action::Hide => clear_active_tooltip(active_tooltip, window),
3001 Action::ScheduleHide(tooltip) => {
3002 let delayed_hide_task = window.spawn(cx, {
3003 let active_tooltip = active_tooltip.clone();
3004 async move |cx| {
3005 cx.background_executor()
3006 .timer(HOVERABLE_TOOLTIP_HIDE_DELAY)
3007 .await;
3008 if active_tooltip.borrow_mut().take().is_some() {
3009 cx.update(|window, _cx| window.refresh()).ok();
3010 }
3011 }
3012 });
3013 active_tooltip
3014 .borrow_mut()
3015 .replace(ActiveTooltip::WaitingForHide {
3016 tooltip,
3017 _task: delayed_hide_task,
3018 });
3019 }
3020 Action::CancelHide(tooltip) => {
3021 // Cancel waiting to hide tooltip when it becomes hovered.
3022 active_tooltip.borrow_mut().replace(ActiveTooltip::Visible {
3023 tooltip,
3024 is_hoverable: true,
3025 });
3026 }
3027 }
3028
3029 active_tooltip.borrow().is_some()
3030}
3031
3032#[derive(Default)]
3033pub(crate) struct GroupHitboxes(HashMap<SharedString, SmallVec<[HitboxId; 1]>>);
3034
3035impl Global for GroupHitboxes {}
3036
3037impl GroupHitboxes {
3038 pub fn get(name: &SharedString, cx: &mut App) -> Option<HitboxId> {
3039 cx.default_global::<Self>()
3040 .0
3041 .get(name)
3042 .and_then(|bounds_stack| bounds_stack.last())
3043 .cloned()
3044 }
3045
3046 pub fn push(name: SharedString, hitbox_id: HitboxId, cx: &mut App) {
3047 cx.default_global::<Self>()
3048 .0
3049 .entry(name)
3050 .or_default()
3051 .push(hitbox_id);
3052 }
3053
3054 pub fn pop(name: &SharedString, cx: &mut App) {
3055 cx.default_global::<Self>().0.get_mut(name).unwrap().pop();
3056 }
3057}
3058
3059/// A wrapper around an element that can store state, produced after assigning an ElementId.
3060pub struct Stateful<E> {
3061 pub(crate) element: E,
3062}
3063
3064impl<E> Styled for Stateful<E>
3065where
3066 E: Styled,
3067{
3068 fn style(&mut self) -> &mut StyleRefinement {
3069 self.element.style()
3070 }
3071}
3072
3073impl<E> StatefulInteractiveElement for Stateful<E>
3074where
3075 E: Element,
3076 Self: InteractiveElement,
3077{
3078}
3079
3080impl<E> InteractiveElement for Stateful<E>
3081where
3082 E: InteractiveElement,
3083{
3084 fn interactivity(&mut self) -> &mut Interactivity {
3085 self.element.interactivity()
3086 }
3087}
3088
3089impl<E> Element for Stateful<E>
3090where
3091 E: Element,
3092{
3093 type RequestLayoutState = E::RequestLayoutState;
3094 type PrepaintState = E::PrepaintState;
3095
3096 fn id(&self) -> Option<ElementId> {
3097 self.element.id()
3098 }
3099
3100 fn source_location(&self) -> Option<&'static core::panic::Location<'static>> {
3101 self.element.source_location()
3102 }
3103
3104 fn request_layout(
3105 &mut self,
3106 id: Option<&GlobalElementId>,
3107 inspector_id: Option<&InspectorElementId>,
3108 window: &mut Window,
3109 cx: &mut App,
3110 ) -> (LayoutId, Self::RequestLayoutState) {
3111 self.element.request_layout(id, inspector_id, window, cx)
3112 }
3113
3114 fn prepaint(
3115 &mut self,
3116 id: Option<&GlobalElementId>,
3117 inspector_id: Option<&InspectorElementId>,
3118 bounds: Bounds<Pixels>,
3119 state: &mut Self::RequestLayoutState,
3120 window: &mut Window,
3121 cx: &mut App,
3122 ) -> E::PrepaintState {
3123 self.element
3124 .prepaint(id, inspector_id, bounds, state, window, cx)
3125 }
3126
3127 fn paint(
3128 &mut self,
3129 id: Option<&GlobalElementId>,
3130 inspector_id: Option<&InspectorElementId>,
3131 bounds: Bounds<Pixels>,
3132 request_layout: &mut Self::RequestLayoutState,
3133 prepaint: &mut Self::PrepaintState,
3134 window: &mut Window,
3135 cx: &mut App,
3136 ) {
3137 self.element.paint(
3138 id,
3139 inspector_id,
3140 bounds,
3141 request_layout,
3142 prepaint,
3143 window,
3144 cx,
3145 );
3146 }
3147}
3148
3149impl<E> IntoElement for Stateful<E>
3150where
3151 E: Element,
3152{
3153 type Element = Self;
3154
3155 fn into_element(self) -> Self::Element {
3156 self
3157 }
3158}
3159
3160impl<E> ParentElement for Stateful<E>
3161where
3162 E: ParentElement,
3163{
3164 fn extend(&mut self, elements: impl IntoIterator<Item = AnyElement>) {
3165 self.element.extend(elements)
3166 }
3167}
3168
3169/// Represents an element that can be scrolled *to* in its parent element.
3170/// Contrary to [ScrollHandle::scroll_to_active_item], an anchored element does not have to be an immediate child of the parent.
3171#[derive(Clone)]
3172pub struct ScrollAnchor {
3173 handle: ScrollHandle,
3174 last_origin: Rc<RefCell<Point<Pixels>>>,
3175}
3176
3177impl ScrollAnchor {
3178 /// Creates a [ScrollAnchor] associated with a given [ScrollHandle].
3179 pub fn for_handle(handle: ScrollHandle) -> Self {
3180 Self {
3181 handle,
3182 last_origin: Default::default(),
3183 }
3184 }
3185 /// Request scroll to this item on the next frame.
3186 pub fn scroll_to(&self, window: &mut Window, _cx: &mut App) {
3187 let this = self.clone();
3188
3189 window.on_next_frame(move |_, _| {
3190 let viewport_bounds = this.handle.bounds();
3191 let self_bounds = *this.last_origin.borrow();
3192 this.handle.set_offset(viewport_bounds.origin - self_bounds);
3193 });
3194 }
3195}
3196
3197#[derive(Default, Debug)]
3198struct ScrollHandleState {
3199 offset: Rc<RefCell<Point<Pixels>>>,
3200 bounds: Bounds<Pixels>,
3201 max_offset: Size<Pixels>,
3202 child_bounds: Vec<Bounds<Pixels>>,
3203 scroll_to_bottom: bool,
3204 overflow: Point<Overflow>,
3205 active_item: Option<ScrollActiveItem>,
3206}
3207
3208#[derive(Default, Debug, Clone, Copy)]
3209struct ScrollActiveItem {
3210 index: usize,
3211 strategy: ScrollStrategy,
3212}
3213
3214#[derive(Default, Debug, Clone, Copy)]
3215enum ScrollStrategy {
3216 #[default]
3217 FirstVisible,
3218 Top,
3219}
3220
3221/// A handle to the scrollable aspects of an element.
3222/// Used for accessing scroll state, like the current scroll offset,
3223/// and for mutating the scroll state, like scrolling to a specific child.
3224#[derive(Clone, Debug)]
3225pub struct ScrollHandle(Rc<RefCell<ScrollHandleState>>);
3226
3227impl Default for ScrollHandle {
3228 fn default() -> Self {
3229 Self::new()
3230 }
3231}
3232
3233impl ScrollHandle {
3234 /// Construct a new scroll handle.
3235 pub fn new() -> Self {
3236 Self(Rc::default())
3237 }
3238
3239 /// Get the current scroll offset.
3240 pub fn offset(&self) -> Point<Pixels> {
3241 *self.0.borrow().offset.borrow()
3242 }
3243
3244 /// Get the maximum scroll offset.
3245 pub fn max_offset(&self) -> Size<Pixels> {
3246 self.0.borrow().max_offset
3247 }
3248
3249 /// Get the top child that's scrolled into view.
3250 pub fn top_item(&self) -> usize {
3251 let state = self.0.borrow();
3252 let top = state.bounds.top() - state.offset.borrow().y;
3253
3254 match state.child_bounds.binary_search_by(|bounds| {
3255 if top < bounds.top() {
3256 Ordering::Greater
3257 } else if top > bounds.bottom() {
3258 Ordering::Less
3259 } else {
3260 Ordering::Equal
3261 }
3262 }) {
3263 Ok(ix) => ix,
3264 Err(ix) => ix.min(state.child_bounds.len().saturating_sub(1)),
3265 }
3266 }
3267
3268 /// Get the bottom child that's scrolled into view.
3269 pub fn bottom_item(&self) -> usize {
3270 let state = self.0.borrow();
3271 let bottom = state.bounds.bottom() - state.offset.borrow().y;
3272
3273 match state.child_bounds.binary_search_by(|bounds| {
3274 if bottom < bounds.top() {
3275 Ordering::Greater
3276 } else if bottom > bounds.bottom() {
3277 Ordering::Less
3278 } else {
3279 Ordering::Equal
3280 }
3281 }) {
3282 Ok(ix) => ix,
3283 Err(ix) => ix.min(state.child_bounds.len().saturating_sub(1)),
3284 }
3285 }
3286
3287 /// Return the bounds into which this child is painted
3288 pub fn bounds(&self) -> Bounds<Pixels> {
3289 self.0.borrow().bounds
3290 }
3291
3292 /// Get the bounds for a specific child.
3293 pub fn bounds_for_item(&self, ix: usize) -> Option<Bounds<Pixels>> {
3294 self.0.borrow().child_bounds.get(ix).cloned()
3295 }
3296
3297 /// Update [ScrollHandleState]'s active item for scrolling to in prepaint
3298 pub fn scroll_to_item(&self, ix: usize) {
3299 let mut state = self.0.borrow_mut();
3300 state.active_item = Some(ScrollActiveItem {
3301 index: ix,
3302 strategy: ScrollStrategy::default(),
3303 });
3304 }
3305
3306 /// Update [ScrollHandleState]'s active item for scrolling to in prepaint
3307 /// This scrolls the minimal amount to ensure that the child is the first visible element
3308 pub fn scroll_to_top_of_item(&self, ix: usize) {
3309 let mut state = self.0.borrow_mut();
3310 state.active_item = Some(ScrollActiveItem {
3311 index: ix,
3312 strategy: ScrollStrategy::Top,
3313 });
3314 }
3315
3316 /// Scrolls the minimal amount to either ensure that the child is
3317 /// fully visible or the top element of the view depends on the
3318 /// scroll strategy
3319 fn scroll_to_active_item(&self) {
3320 let mut state = self.0.borrow_mut();
3321
3322 let Some(active_item) = state.active_item else {
3323 return;
3324 };
3325
3326 let active_item = match state.child_bounds.get(active_item.index) {
3327 Some(bounds) => {
3328 let mut scroll_offset = state.offset.borrow_mut();
3329
3330 match active_item.strategy {
3331 ScrollStrategy::FirstVisible => {
3332 if state.overflow.y == Overflow::Scroll {
3333 let child_height = bounds.size.height;
3334 let viewport_height = state.bounds.size.height;
3335 if child_height > viewport_height {
3336 scroll_offset.y = state.bounds.top() - bounds.top();
3337 } else if bounds.top() + scroll_offset.y < state.bounds.top() {
3338 scroll_offset.y = state.bounds.top() - bounds.top();
3339 } else if bounds.bottom() + scroll_offset.y > state.bounds.bottom() {
3340 scroll_offset.y = state.bounds.bottom() - bounds.bottom();
3341 }
3342 }
3343 }
3344 ScrollStrategy::Top => {
3345 scroll_offset.y = state.bounds.top() - bounds.top();
3346 }
3347 }
3348
3349 if state.overflow.x == Overflow::Scroll {
3350 let child_width = bounds.size.width;
3351 let viewport_width = state.bounds.size.width;
3352 if child_width > viewport_width {
3353 scroll_offset.x = state.bounds.left() - bounds.left();
3354 } else if bounds.left() + scroll_offset.x < state.bounds.left() {
3355 scroll_offset.x = state.bounds.left() - bounds.left();
3356 } else if bounds.right() + scroll_offset.x > state.bounds.right() {
3357 scroll_offset.x = state.bounds.right() - bounds.right();
3358 }
3359 }
3360 None
3361 }
3362 None => Some(active_item),
3363 };
3364 state.active_item = active_item;
3365 }
3366
3367 /// Scrolls to the bottom.
3368 pub fn scroll_to_bottom(&self) {
3369 let mut state = self.0.borrow_mut();
3370 state.scroll_to_bottom = true;
3371 }
3372
3373 /// Set the offset explicitly. The offset is the distance from the top left of the
3374 /// parent container to the top left of the first child.
3375 /// As you scroll further down the offset becomes more negative.
3376 pub fn set_offset(&self, mut position: Point<Pixels>) {
3377 let state = self.0.borrow();
3378 *state.offset.borrow_mut() = position;
3379 }
3380
3381 /// Get the logical scroll top, based on a child index and a pixel offset.
3382 pub fn logical_scroll_top(&self) -> (usize, Pixels) {
3383 let ix = self.top_item();
3384 let state = self.0.borrow();
3385
3386 if let Some(child_bounds) = state.child_bounds.get(ix) {
3387 (
3388 ix,
3389 child_bounds.top() + state.offset.borrow().y - state.bounds.top(),
3390 )
3391 } else {
3392 (ix, px(0.))
3393 }
3394 }
3395
3396 /// Get the logical scroll bottom, based on a child index and a pixel offset.
3397 pub fn logical_scroll_bottom(&self) -> (usize, Pixels) {
3398 let ix = self.bottom_item();
3399 let state = self.0.borrow();
3400
3401 if let Some(child_bounds) = state.child_bounds.get(ix) {
3402 (
3403 ix,
3404 child_bounds.bottom() + state.offset.borrow().y - state.bounds.bottom(),
3405 )
3406 } else {
3407 (ix, px(0.))
3408 }
3409 }
3410
3411 /// Get the count of children for scrollable item.
3412 pub fn children_count(&self) -> usize {
3413 self.0.borrow().child_bounds.len()
3414 }
3415}
3416
3417#[cfg(test)]
3418mod tests {
3419 use super::*;
3420
3421 #[test]
3422 fn scroll_handle_aligns_wide_children_to_left_edge() {
3423 let handle = ScrollHandle::new();
3424 {
3425 let mut state = handle.0.borrow_mut();
3426 state.bounds = Bounds::new(point(px(0.), px(0.)), size(px(80.), px(20.)));
3427 state.child_bounds = vec![Bounds::new(point(px(25.), px(0.)), size(px(200.), px(20.)))];
3428 state.overflow.x = Overflow::Scroll;
3429 state.active_item = Some(ScrollActiveItem {
3430 index: 0,
3431 strategy: ScrollStrategy::default(),
3432 });
3433 }
3434
3435 handle.scroll_to_active_item();
3436
3437 assert_eq!(handle.offset().x, px(-25.));
3438 }
3439
3440 #[test]
3441 fn scroll_handle_aligns_tall_children_to_top_edge() {
3442 let handle = ScrollHandle::new();
3443 {
3444 let mut state = handle.0.borrow_mut();
3445 state.bounds = Bounds::new(point(px(0.), px(0.)), size(px(20.), px(80.)));
3446 state.child_bounds = vec![Bounds::new(point(px(0.), px(25.)), size(px(20.), px(200.)))];
3447 state.overflow.y = Overflow::Scroll;
3448 state.active_item = Some(ScrollActiveItem {
3449 index: 0,
3450 strategy: ScrollStrategy::default(),
3451 });
3452 }
3453
3454 handle.scroll_to_active_item();
3455
3456 assert_eq!(handle.offset().y, px(-25.));
3457 }
3458}