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 image_cache = self
1429 .image_cache
1430 .as_mut()
1431 .map(|provider| provider.provide(window, cx));
1432
1433 let has_prepaint_listener = self.prepaint_listener.is_some();
1434 let mut children_bounds = Vec::with_capacity(if has_prepaint_listener {
1435 request_layout.child_layout_ids.len()
1436 } else {
1437 0
1438 });
1439
1440 let mut child_min = point(Pixels::MAX, Pixels::MAX);
1441 let mut child_max = Point::default();
1442 if let Some(handle) = self.interactivity.scroll_anchor.as_ref() {
1443 *handle.last_origin.borrow_mut() = bounds.origin - window.element_offset();
1444 }
1445 let content_size = if request_layout.child_layout_ids.is_empty() {
1446 bounds.size
1447 } else if let Some(scroll_handle) = self.interactivity.tracked_scroll_handle.as_ref() {
1448 let mut state = scroll_handle.0.borrow_mut();
1449 state.child_bounds = Vec::with_capacity(request_layout.child_layout_ids.len());
1450 for child_layout_id in &request_layout.child_layout_ids {
1451 let child_bounds = window.layout_bounds(*child_layout_id);
1452 child_min = child_min.min(&child_bounds.origin);
1453 child_max = child_max.max(&child_bounds.bottom_right());
1454 state.child_bounds.push(child_bounds);
1455 }
1456 (child_max - child_min).into()
1457 } else {
1458 for child_layout_id in &request_layout.child_layout_ids {
1459 let child_bounds = window.layout_bounds(*child_layout_id);
1460 child_min = child_min.min(&child_bounds.origin);
1461 child_max = child_max.max(&child_bounds.bottom_right());
1462
1463 if has_prepaint_listener {
1464 children_bounds.push(child_bounds);
1465 }
1466 }
1467 (child_max - child_min).into()
1468 };
1469
1470 if let Some(scroll_handle) = self.interactivity.tracked_scroll_handle.as_ref() {
1471 scroll_handle.scroll_to_active_item();
1472 }
1473
1474 self.interactivity.prepaint(
1475 global_id,
1476 inspector_id,
1477 bounds,
1478 content_size,
1479 window,
1480 cx,
1481 |style, scroll_offset, hitbox, window, cx| {
1482 // skip children
1483 if style.display == Display::None {
1484 return hitbox;
1485 }
1486
1487 window.with_image_cache(image_cache, |window| {
1488 window.with_element_offset(scroll_offset, |window| {
1489 for child in &mut self.children {
1490 child.prepaint(window, cx);
1491 }
1492 });
1493
1494 if let Some(listener) = self.prepaint_listener.as_ref() {
1495 listener(children_bounds, window, cx);
1496 }
1497 });
1498
1499 hitbox
1500 },
1501 )
1502 }
1503
1504 #[stacksafe]
1505 fn paint(
1506 &mut self,
1507 global_id: Option<&GlobalElementId>,
1508 inspector_id: Option<&InspectorElementId>,
1509 bounds: Bounds<Pixels>,
1510 _request_layout: &mut Self::RequestLayoutState,
1511 hitbox: &mut Option<Hitbox>,
1512 window: &mut Window,
1513 cx: &mut App,
1514 ) {
1515 let image_cache = self
1516 .image_cache
1517 .as_mut()
1518 .map(|provider| provider.provide(window, cx));
1519
1520 window.with_image_cache(image_cache, |window| {
1521 self.interactivity.paint(
1522 global_id,
1523 inspector_id,
1524 bounds,
1525 hitbox.as_ref(),
1526 window,
1527 cx,
1528 |style, window, cx| {
1529 // skip children
1530 if style.display == Display::None {
1531 return;
1532 }
1533
1534 for child in &mut self.children {
1535 child.paint(window, cx);
1536 }
1537 },
1538 )
1539 });
1540 }
1541}
1542
1543impl IntoElement for Div {
1544 type Element = Self;
1545
1546 fn into_element(self) -> Self::Element {
1547 self
1548 }
1549}
1550
1551/// The interactivity struct. Powers all of the general-purpose
1552/// interactivity in the `Div` element.
1553#[derive(Default)]
1554pub struct Interactivity {
1555 /// The element ID of the element. In id is required to support a stateful subset of the interactivity such as on_click.
1556 pub element_id: Option<ElementId>,
1557 /// Whether the element was clicked. This will only be present after layout.
1558 pub active: Option<bool>,
1559 /// Whether the element was hovered. This will only be present after paint if an hitbox
1560 /// was created for the interactive element.
1561 pub hovered: Option<bool>,
1562 pub(crate) tooltip_id: Option<TooltipId>,
1563 pub(crate) content_size: Size<Pixels>,
1564 pub(crate) key_context: Option<KeyContext>,
1565 pub(crate) focusable: bool,
1566 pub(crate) tracked_focus_handle: Option<FocusHandle>,
1567 pub(crate) tracked_scroll_handle: Option<ScrollHandle>,
1568 pub(crate) scroll_anchor: Option<ScrollAnchor>,
1569 pub(crate) scroll_offset: Option<Rc<RefCell<Point<Pixels>>>>,
1570 pub(crate) group: Option<SharedString>,
1571 /// The base style of the element, before any modifications are applied
1572 /// by focus, active, etc.
1573 pub base_style: Box<StyleRefinement>,
1574 pub(crate) focus_style: Option<Box<StyleRefinement>>,
1575 pub(crate) in_focus_style: Option<Box<StyleRefinement>>,
1576 pub(crate) focus_visible_style: Option<Box<StyleRefinement>>,
1577 pub(crate) hover_style: Option<Box<StyleRefinement>>,
1578 pub(crate) group_hover_style: Option<GroupStyle>,
1579 pub(crate) active_style: Option<Box<StyleRefinement>>,
1580 pub(crate) group_active_style: Option<GroupStyle>,
1581 pub(crate) drag_over_styles: Vec<(
1582 TypeId,
1583 Box<dyn Fn(&dyn Any, &mut Window, &mut App) -> StyleRefinement>,
1584 )>,
1585 pub(crate) group_drag_over_styles: Vec<(TypeId, GroupStyle)>,
1586 pub(crate) mouse_down_listeners: Vec<MouseDownListener>,
1587 pub(crate) mouse_up_listeners: Vec<MouseUpListener>,
1588 pub(crate) mouse_pressure_listeners: Vec<MousePressureListener>,
1589 pub(crate) mouse_move_listeners: Vec<MouseMoveListener>,
1590 pub(crate) scroll_wheel_listeners: Vec<ScrollWheelListener>,
1591 pub(crate) key_down_listeners: Vec<KeyDownListener>,
1592 pub(crate) key_up_listeners: Vec<KeyUpListener>,
1593 pub(crate) modifiers_changed_listeners: Vec<ModifiersChangedListener>,
1594 pub(crate) action_listeners: Vec<(TypeId, ActionListener)>,
1595 pub(crate) drop_listeners: Vec<(TypeId, DropListener)>,
1596 pub(crate) can_drop_predicate: Option<CanDropPredicate>,
1597 pub(crate) click_listeners: Vec<ClickListener>,
1598 pub(crate) drag_listener: Option<(Arc<dyn Any>, DragListener)>,
1599 pub(crate) hover_listener: Option<Box<dyn Fn(&bool, &mut Window, &mut App)>>,
1600 pub(crate) tooltip_builder: Option<TooltipBuilder>,
1601 pub(crate) window_control: Option<WindowControlArea>,
1602 pub(crate) hitbox_behavior: HitboxBehavior,
1603 pub(crate) tab_index: Option<isize>,
1604 pub(crate) tab_group: bool,
1605 pub(crate) tab_stop: bool,
1606
1607 #[cfg(any(feature = "inspector", debug_assertions))]
1608 pub(crate) source_location: Option<&'static core::panic::Location<'static>>,
1609
1610 #[cfg(any(test, feature = "test-support"))]
1611 pub(crate) debug_selector: Option<String>,
1612}
1613
1614impl Interactivity {
1615 /// Layout this element according to this interactivity state's configured styles
1616 pub fn request_layout(
1617 &mut self,
1618 global_id: Option<&GlobalElementId>,
1619 _inspector_id: Option<&InspectorElementId>,
1620 window: &mut Window,
1621 cx: &mut App,
1622 f: impl FnOnce(Style, &mut Window, &mut App) -> LayoutId,
1623 ) -> LayoutId {
1624 #[cfg(any(feature = "inspector", debug_assertions))]
1625 window.with_inspector_state(
1626 _inspector_id,
1627 cx,
1628 |inspector_state: &mut Option<DivInspectorState>, _window| {
1629 if let Some(inspector_state) = inspector_state {
1630 self.base_style = inspector_state.base_style.clone();
1631 } else {
1632 *inspector_state = Some(DivInspectorState {
1633 base_style: self.base_style.clone(),
1634 bounds: Default::default(),
1635 content_size: Default::default(),
1636 })
1637 }
1638 },
1639 );
1640
1641 window.with_optional_element_state::<InteractiveElementState, _>(
1642 global_id,
1643 |element_state, window| {
1644 let mut element_state =
1645 element_state.map(|element_state| element_state.unwrap_or_default());
1646
1647 if let Some(element_state) = element_state.as_ref()
1648 && cx.has_active_drag()
1649 {
1650 if let Some(pending_mouse_down) = element_state.pending_mouse_down.as_ref() {
1651 *pending_mouse_down.borrow_mut() = None;
1652 }
1653 if let Some(clicked_state) = element_state.clicked_state.as_ref() {
1654 *clicked_state.borrow_mut() = ElementClickedState::default();
1655 }
1656 }
1657
1658 // Ensure we store a focus handle in our element state if we're focusable.
1659 // If there's an explicit focus handle we're tracking, use that. Otherwise
1660 // create a new handle and store it in the element state, which lives for as
1661 // as frames contain an element with this id.
1662 if self.focusable
1663 && self.tracked_focus_handle.is_none()
1664 && let Some(element_state) = element_state.as_mut()
1665 {
1666 let mut handle = element_state
1667 .focus_handle
1668 .get_or_insert_with(|| cx.focus_handle())
1669 .clone()
1670 .tab_stop(self.tab_stop);
1671
1672 if let Some(index) = self.tab_index {
1673 handle = handle.tab_index(index);
1674 }
1675
1676 self.tracked_focus_handle = Some(handle);
1677 }
1678
1679 if let Some(scroll_handle) = self.tracked_scroll_handle.as_ref() {
1680 self.scroll_offset = Some(scroll_handle.0.borrow().offset.clone());
1681 } else if (self.base_style.overflow.x == Some(Overflow::Scroll)
1682 || self.base_style.overflow.y == Some(Overflow::Scroll))
1683 && let Some(element_state) = element_state.as_mut()
1684 {
1685 self.scroll_offset = Some(
1686 element_state
1687 .scroll_offset
1688 .get_or_insert_with(Rc::default)
1689 .clone(),
1690 );
1691 }
1692
1693 let style = self.compute_style_internal(None, element_state.as_mut(), window, cx);
1694 let layout_id = f(style, window, cx);
1695 (layout_id, element_state)
1696 },
1697 )
1698 }
1699
1700 /// Commit the bounds of this element according to this interactivity state's configured styles.
1701 pub fn prepaint<R>(
1702 &mut self,
1703 global_id: Option<&GlobalElementId>,
1704 _inspector_id: Option<&InspectorElementId>,
1705 bounds: Bounds<Pixels>,
1706 content_size: Size<Pixels>,
1707 window: &mut Window,
1708 cx: &mut App,
1709 f: impl FnOnce(&Style, Point<Pixels>, Option<Hitbox>, &mut Window, &mut App) -> R,
1710 ) -> R {
1711 self.content_size = content_size;
1712
1713 #[cfg(any(feature = "inspector", debug_assertions))]
1714 window.with_inspector_state(
1715 _inspector_id,
1716 cx,
1717 |inspector_state: &mut Option<DivInspectorState>, _window| {
1718 if let Some(inspector_state) = inspector_state {
1719 inspector_state.bounds = bounds;
1720 inspector_state.content_size = content_size;
1721 }
1722 },
1723 );
1724
1725 if let Some(focus_handle) = self.tracked_focus_handle.as_ref() {
1726 window.set_focus_handle(focus_handle, cx);
1727 }
1728 window.with_optional_element_state::<InteractiveElementState, _>(
1729 global_id,
1730 |element_state, window| {
1731 let mut element_state =
1732 element_state.map(|element_state| element_state.unwrap_or_default());
1733 let style = self.compute_style_internal(None, element_state.as_mut(), window, cx);
1734
1735 if let Some(element_state) = element_state.as_mut() {
1736 if let Some(clicked_state) = element_state.clicked_state.as_ref() {
1737 let clicked_state = clicked_state.borrow();
1738 self.active = Some(clicked_state.element);
1739 }
1740 if self.hover_style.is_some() || self.group_hover_style.is_some() {
1741 element_state
1742 .hover_state
1743 .get_or_insert_with(Default::default);
1744 }
1745 if let Some(active_tooltip) = element_state.active_tooltip.as_ref() {
1746 if self.tooltip_builder.is_some() {
1747 self.tooltip_id = set_tooltip_on_window(active_tooltip, window);
1748 } else {
1749 // If there is no longer a tooltip builder, remove the active tooltip.
1750 element_state.active_tooltip.take();
1751 }
1752 }
1753 }
1754
1755 window.with_text_style(style.text_style().cloned(), |window| {
1756 window.with_content_mask(
1757 style.overflow_mask(bounds, window.rem_size()),
1758 |window| {
1759 let hitbox = if self.should_insert_hitbox(&style, window, cx) {
1760 Some(window.insert_hitbox(bounds, self.hitbox_behavior))
1761 } else {
1762 None
1763 };
1764
1765 let scroll_offset =
1766 self.clamp_scroll_position(bounds, &style, window, cx);
1767 let result = f(&style, scroll_offset, hitbox, window, cx);
1768 (result, element_state)
1769 },
1770 )
1771 })
1772 },
1773 )
1774 }
1775
1776 fn should_insert_hitbox(&self, style: &Style, window: &Window, cx: &App) -> bool {
1777 self.hitbox_behavior != HitboxBehavior::Normal
1778 || self.window_control.is_some()
1779 || style.mouse_cursor.is_some()
1780 || self.group.is_some()
1781 || self.scroll_offset.is_some()
1782 || self.tracked_focus_handle.is_some()
1783 || self.hover_style.is_some()
1784 || self.group_hover_style.is_some()
1785 || self.hover_listener.is_some()
1786 || !self.mouse_up_listeners.is_empty()
1787 || !self.mouse_pressure_listeners.is_empty()
1788 || !self.mouse_down_listeners.is_empty()
1789 || !self.mouse_move_listeners.is_empty()
1790 || !self.click_listeners.is_empty()
1791 || !self.scroll_wheel_listeners.is_empty()
1792 || self.drag_listener.is_some()
1793 || !self.drop_listeners.is_empty()
1794 || self.tooltip_builder.is_some()
1795 || window.is_inspector_picking(cx)
1796 }
1797
1798 fn clamp_scroll_position(
1799 &self,
1800 bounds: Bounds<Pixels>,
1801 style: &Style,
1802 window: &mut Window,
1803 _cx: &mut App,
1804 ) -> Point<Pixels> {
1805 fn round_to_two_decimals(pixels: Pixels) -> Pixels {
1806 const ROUNDING_FACTOR: f32 = 100.0;
1807 (pixels * ROUNDING_FACTOR).round() / ROUNDING_FACTOR
1808 }
1809
1810 if let Some(scroll_offset) = self.scroll_offset.as_ref() {
1811 let mut scroll_to_bottom = false;
1812 let mut tracked_scroll_handle = self
1813 .tracked_scroll_handle
1814 .as_ref()
1815 .map(|handle| handle.0.borrow_mut());
1816 if let Some(mut scroll_handle_state) = tracked_scroll_handle.as_deref_mut() {
1817 scroll_handle_state.overflow = style.overflow;
1818 scroll_to_bottom = mem::take(&mut scroll_handle_state.scroll_to_bottom);
1819 }
1820
1821 let rem_size = window.rem_size();
1822 let padding = style.padding.to_pixels(bounds.size.into(), rem_size);
1823 let padding_size = size(padding.left + padding.right, padding.top + padding.bottom);
1824 // The floating point values produced by Taffy and ours often vary
1825 // slightly after ~5 decimal places. This can lead to cases where after
1826 // subtracting these, the container becomes scrollable for less than
1827 // 0.00000x pixels. As we generally don't benefit from a precision that
1828 // high for the maximum scroll, we round the scroll max to 2 decimal
1829 // places here.
1830 let padded_content_size = self.content_size + padding_size;
1831 let scroll_max = (padded_content_size - bounds.size)
1832 .map(round_to_two_decimals)
1833 .max(&Default::default());
1834 // Clamp scroll offset in case scroll max is smaller now (e.g., if children
1835 // were removed or the bounds became larger).
1836 let mut scroll_offset = scroll_offset.borrow_mut();
1837
1838 scroll_offset.x = scroll_offset.x.clamp(-scroll_max.width, px(0.));
1839 if scroll_to_bottom {
1840 scroll_offset.y = -scroll_max.height;
1841 } else {
1842 scroll_offset.y = scroll_offset.y.clamp(-scroll_max.height, px(0.));
1843 }
1844
1845 if let Some(mut scroll_handle_state) = tracked_scroll_handle {
1846 scroll_handle_state.max_offset = scroll_max;
1847 scroll_handle_state.bounds = bounds;
1848 }
1849
1850 *scroll_offset
1851 } else {
1852 Point::default()
1853 }
1854 }
1855
1856 /// Paint this element according to this interactivity state's configured styles
1857 /// and bind the element's mouse and keyboard events.
1858 ///
1859 /// content_size is the size of the content of the element, which may be larger than the
1860 /// element's bounds if the element is scrollable.
1861 ///
1862 /// the final computed style will be passed to the provided function, along
1863 /// with the current scroll offset
1864 pub fn paint(
1865 &mut self,
1866 global_id: Option<&GlobalElementId>,
1867 _inspector_id: Option<&InspectorElementId>,
1868 bounds: Bounds<Pixels>,
1869 hitbox: Option<&Hitbox>,
1870 window: &mut Window,
1871 cx: &mut App,
1872 f: impl FnOnce(&Style, &mut Window, &mut App),
1873 ) {
1874 self.hovered = hitbox.map(|hitbox| hitbox.is_hovered(window));
1875 window.with_optional_element_state::<InteractiveElementState, _>(
1876 global_id,
1877 |element_state, window| {
1878 let mut element_state =
1879 element_state.map(|element_state| element_state.unwrap_or_default());
1880
1881 let style = self.compute_style_internal(hitbox, element_state.as_mut(), window, cx);
1882
1883 #[cfg(any(feature = "test-support", test))]
1884 if let Some(debug_selector) = &self.debug_selector {
1885 window
1886 .next_frame
1887 .debug_bounds
1888 .insert(debug_selector.clone(), bounds);
1889 }
1890
1891 self.paint_hover_group_handler(window, cx);
1892
1893 if style.visibility == Visibility::Hidden {
1894 return ((), element_state);
1895 }
1896
1897 let mut tab_group = None;
1898 if self.tab_group {
1899 tab_group = self.tab_index;
1900 }
1901 if let Some(focus_handle) = &self.tracked_focus_handle {
1902 window.next_frame.tab_stops.insert(focus_handle);
1903 }
1904
1905 window.with_element_opacity(style.opacity, |window| {
1906 style.paint(bounds, window, cx, |window: &mut Window, cx: &mut App| {
1907 window.with_text_style(style.text_style().cloned(), |window| {
1908 window.with_content_mask(
1909 style.overflow_mask(bounds, window.rem_size()),
1910 |window| {
1911 window.with_tab_group(tab_group, |window| {
1912 if let Some(hitbox) = hitbox {
1913 #[cfg(debug_assertions)]
1914 self.paint_debug_info(
1915 global_id, hitbox, &style, window, cx,
1916 );
1917
1918 if let Some(drag) = cx.active_drag.as_ref() {
1919 if let Some(mouse_cursor) = drag.cursor_style {
1920 window.set_window_cursor_style(mouse_cursor);
1921 }
1922 } else {
1923 if let Some(mouse_cursor) = style.mouse_cursor {
1924 window.set_cursor_style(mouse_cursor, hitbox);
1925 }
1926 }
1927
1928 if let Some(group) = self.group.clone() {
1929 GroupHitboxes::push(group, hitbox.id, cx);
1930 }
1931
1932 if let Some(area) = self.window_control {
1933 window.insert_window_control_hitbox(
1934 area,
1935 hitbox.clone(),
1936 );
1937 }
1938
1939 self.paint_mouse_listeners(
1940 hitbox,
1941 element_state.as_mut(),
1942 window,
1943 cx,
1944 );
1945 self.paint_scroll_listener(hitbox, &style, window, cx);
1946 }
1947
1948 self.paint_keyboard_listeners(window, cx);
1949 f(&style, window, cx);
1950
1951 if let Some(_hitbox) = hitbox {
1952 #[cfg(any(feature = "inspector", debug_assertions))]
1953 window.insert_inspector_hitbox(
1954 _hitbox.id,
1955 _inspector_id,
1956 cx,
1957 );
1958
1959 if let Some(group) = self.group.as_ref() {
1960 GroupHitboxes::pop(group, cx);
1961 }
1962 }
1963 })
1964 },
1965 );
1966 });
1967 });
1968 });
1969
1970 ((), element_state)
1971 },
1972 );
1973 }
1974
1975 #[cfg(debug_assertions)]
1976 fn paint_debug_info(
1977 &self,
1978 global_id: Option<&GlobalElementId>,
1979 hitbox: &Hitbox,
1980 style: &Style,
1981 window: &mut Window,
1982 cx: &mut App,
1983 ) {
1984 use crate::{BorderStyle, TextAlign};
1985
1986 if let Some(global_id) = global_id
1987 && (style.debug || style.debug_below || cx.has_global::<crate::DebugBelow>())
1988 && hitbox.is_hovered(window)
1989 {
1990 const FONT_SIZE: crate::Pixels = crate::Pixels(10.);
1991 let element_id = format!("{global_id:?}");
1992 let str_len = element_id.len();
1993
1994 let render_debug_text = |window: &mut Window| {
1995 if let Some(text) = window
1996 .text_system()
1997 .shape_text(
1998 element_id.into(),
1999 FONT_SIZE,
2000 &[window.text_style().to_run(str_len)],
2001 None,
2002 None,
2003 )
2004 .ok()
2005 .and_then(|mut text| text.pop())
2006 {
2007 text.paint(hitbox.origin, FONT_SIZE, TextAlign::Left, None, window, cx)
2008 .ok();
2009
2010 let text_bounds = crate::Bounds {
2011 origin: hitbox.origin,
2012 size: text.size(FONT_SIZE),
2013 };
2014 if self.source_location.is_some()
2015 && text_bounds.contains(&window.mouse_position())
2016 && window.modifiers().secondary()
2017 {
2018 let secondary_held = window.modifiers().secondary();
2019 window.on_key_event({
2020 move |e: &crate::ModifiersChangedEvent, _phase, window, _cx| {
2021 if e.modifiers.secondary() != secondary_held
2022 && text_bounds.contains(&window.mouse_position())
2023 {
2024 window.refresh();
2025 }
2026 }
2027 });
2028
2029 let was_hovered = hitbox.is_hovered(window);
2030 let current_view = window.current_view();
2031 window.on_mouse_event({
2032 let hitbox = hitbox.clone();
2033 move |_: &MouseMoveEvent, phase, window, cx| {
2034 if phase == DispatchPhase::Capture {
2035 let hovered = hitbox.is_hovered(window);
2036 if hovered != was_hovered {
2037 cx.notify(current_view)
2038 }
2039 }
2040 }
2041 });
2042
2043 window.on_mouse_event({
2044 let hitbox = hitbox.clone();
2045 let location = self.source_location.unwrap();
2046 move |e: &crate::MouseDownEvent, phase, window, cx| {
2047 if text_bounds.contains(&e.position)
2048 && phase.capture()
2049 && hitbox.is_hovered(window)
2050 {
2051 cx.stop_propagation();
2052 let Ok(dir) = std::env::current_dir() else {
2053 return;
2054 };
2055
2056 eprintln!(
2057 "This element was created at:\n{}:{}:{}",
2058 dir.join(location.file()).to_string_lossy(),
2059 location.line(),
2060 location.column()
2061 );
2062 }
2063 }
2064 });
2065 window.paint_quad(crate::outline(
2066 crate::Bounds {
2067 origin: hitbox.origin
2068 + crate::point(crate::px(0.), FONT_SIZE - px(2.)),
2069 size: crate::Size {
2070 width: text_bounds.size.width,
2071 height: crate::px(1.),
2072 },
2073 },
2074 crate::red(),
2075 BorderStyle::default(),
2076 ))
2077 }
2078 }
2079 };
2080
2081 window.with_text_style(
2082 Some(crate::TextStyleRefinement {
2083 color: Some(crate::red()),
2084 line_height: Some(FONT_SIZE.into()),
2085 background_color: Some(crate::white()),
2086 ..Default::default()
2087 }),
2088 render_debug_text,
2089 )
2090 }
2091 }
2092
2093 fn paint_mouse_listeners(
2094 &mut self,
2095 hitbox: &Hitbox,
2096 element_state: Option<&mut InteractiveElementState>,
2097 window: &mut Window,
2098 cx: &mut App,
2099 ) {
2100 let is_focused = self
2101 .tracked_focus_handle
2102 .as_ref()
2103 .map(|handle| handle.is_focused(window))
2104 .unwrap_or(false);
2105
2106 // If this element can be focused, register a mouse down listener
2107 // that will automatically transfer focus when hitting the element.
2108 // This behavior can be suppressed by using `cx.prevent_default()`.
2109 if let Some(focus_handle) = self.tracked_focus_handle.clone() {
2110 let hitbox = hitbox.clone();
2111 window.on_mouse_event(move |_: &MouseDownEvent, phase, window, cx| {
2112 if phase == DispatchPhase::Bubble
2113 && hitbox.is_hovered(window)
2114 && !window.default_prevented()
2115 {
2116 window.focus(&focus_handle, cx);
2117 // If there is a parent that is also focusable, prevent it
2118 // from transferring focus because we already did so.
2119 window.prevent_default();
2120 }
2121 });
2122 }
2123
2124 for listener in self.mouse_down_listeners.drain(..) {
2125 let hitbox = hitbox.clone();
2126 window.on_mouse_event(move |event: &MouseDownEvent, phase, window, cx| {
2127 listener(event, phase, &hitbox, window, cx);
2128 })
2129 }
2130
2131 for listener in self.mouse_up_listeners.drain(..) {
2132 let hitbox = hitbox.clone();
2133 window.on_mouse_event(move |event: &MouseUpEvent, phase, window, cx| {
2134 listener(event, phase, &hitbox, window, cx);
2135 })
2136 }
2137
2138 for listener in self.mouse_pressure_listeners.drain(..) {
2139 let hitbox = hitbox.clone();
2140 window.on_mouse_event(move |event: &MousePressureEvent, phase, window, cx| {
2141 listener(event, phase, &hitbox, window, cx);
2142 })
2143 }
2144
2145 for listener in self.mouse_move_listeners.drain(..) {
2146 let hitbox = hitbox.clone();
2147 window.on_mouse_event(move |event: &MouseMoveEvent, phase, window, cx| {
2148 listener(event, phase, &hitbox, window, cx);
2149 })
2150 }
2151
2152 for listener in self.scroll_wheel_listeners.drain(..) {
2153 let hitbox = hitbox.clone();
2154 window.on_mouse_event(move |event: &ScrollWheelEvent, phase, window, cx| {
2155 listener(event, phase, &hitbox, window, cx);
2156 })
2157 }
2158
2159 if self.hover_style.is_some()
2160 || self.base_style.mouse_cursor.is_some()
2161 || cx.active_drag.is_some() && !self.drag_over_styles.is_empty()
2162 {
2163 let hitbox = hitbox.clone();
2164 let hover_state = self.hover_style.as_ref().and_then(|_| {
2165 element_state
2166 .as_ref()
2167 .and_then(|state| state.hover_state.as_ref())
2168 .cloned()
2169 });
2170 let current_view = window.current_view();
2171
2172 window.on_mouse_event(move |_: &MouseMoveEvent, phase, window, cx| {
2173 let hovered = hitbox.is_hovered(window);
2174 let was_hovered = hover_state
2175 .as_ref()
2176 .is_some_and(|state| state.borrow().element);
2177 if phase == DispatchPhase::Capture && hovered != was_hovered {
2178 if let Some(hover_state) = &hover_state {
2179 hover_state.borrow_mut().element = hovered;
2180 cx.notify(current_view);
2181 }
2182 }
2183 });
2184 }
2185
2186 if let Some(group_hover) = self.group_hover_style.as_ref() {
2187 if let Some(group_hitbox_id) = GroupHitboxes::get(&group_hover.group, cx) {
2188 let hover_state = element_state
2189 .as_ref()
2190 .and_then(|element| element.hover_state.as_ref())
2191 .cloned();
2192 let current_view = window.current_view();
2193
2194 window.on_mouse_event(move |_: &MouseMoveEvent, phase, window, cx| {
2195 let group_hovered = group_hitbox_id.is_hovered(window);
2196 let was_group_hovered = hover_state
2197 .as_ref()
2198 .is_some_and(|state| state.borrow().group);
2199 if phase == DispatchPhase::Capture && group_hovered != was_group_hovered {
2200 if let Some(hover_state) = &hover_state {
2201 hover_state.borrow_mut().group = group_hovered;
2202 }
2203 cx.notify(current_view);
2204 }
2205 });
2206 }
2207 }
2208
2209 let drag_cursor_style = self.base_style.as_ref().mouse_cursor;
2210
2211 let mut drag_listener = mem::take(&mut self.drag_listener);
2212 let drop_listeners = mem::take(&mut self.drop_listeners);
2213 let click_listeners = mem::take(&mut self.click_listeners);
2214 let can_drop_predicate = mem::take(&mut self.can_drop_predicate);
2215
2216 if !drop_listeners.is_empty() {
2217 let hitbox = hitbox.clone();
2218 window.on_mouse_event({
2219 move |_: &MouseUpEvent, phase, window, cx| {
2220 if let Some(drag) = &cx.active_drag
2221 && phase == DispatchPhase::Bubble
2222 && hitbox.is_hovered(window)
2223 {
2224 let drag_state_type = drag.value.as_ref().type_id();
2225 for (drop_state_type, listener) in &drop_listeners {
2226 if *drop_state_type == drag_state_type {
2227 let drag = cx
2228 .active_drag
2229 .take()
2230 .expect("checked for type drag state type above");
2231
2232 let mut can_drop = true;
2233 if let Some(predicate) = &can_drop_predicate {
2234 can_drop = predicate(drag.value.as_ref(), window, cx);
2235 }
2236
2237 if can_drop {
2238 listener(drag.value.as_ref(), window, cx);
2239 window.refresh();
2240 cx.stop_propagation();
2241 }
2242 }
2243 }
2244 }
2245 }
2246 });
2247 }
2248
2249 if let Some(element_state) = element_state {
2250 if !click_listeners.is_empty() || drag_listener.is_some() {
2251 let pending_mouse_down = element_state
2252 .pending_mouse_down
2253 .get_or_insert_with(Default::default)
2254 .clone();
2255
2256 let clicked_state = element_state
2257 .clicked_state
2258 .get_or_insert_with(Default::default)
2259 .clone();
2260
2261 window.on_mouse_event({
2262 let pending_mouse_down = pending_mouse_down.clone();
2263 let hitbox = hitbox.clone();
2264 move |event: &MouseDownEvent, phase, window, _cx| {
2265 if phase == DispatchPhase::Bubble
2266 && event.button == MouseButton::Left
2267 && hitbox.is_hovered(window)
2268 {
2269 *pending_mouse_down.borrow_mut() = Some(event.clone());
2270 window.refresh();
2271 }
2272 }
2273 });
2274
2275 window.on_mouse_event({
2276 let pending_mouse_down = pending_mouse_down.clone();
2277 let hitbox = hitbox.clone();
2278 move |event: &MouseMoveEvent, phase, window, cx| {
2279 if phase == DispatchPhase::Capture {
2280 return;
2281 }
2282
2283 let mut pending_mouse_down = pending_mouse_down.borrow_mut();
2284 if let Some(mouse_down) = pending_mouse_down.clone()
2285 && !cx.has_active_drag()
2286 && (event.position - mouse_down.position).magnitude() > DRAG_THRESHOLD
2287 && let Some((drag_value, drag_listener)) = drag_listener.take()
2288 {
2289 *clicked_state.borrow_mut() = ElementClickedState::default();
2290 let cursor_offset = event.position - hitbox.origin;
2291 let drag =
2292 (drag_listener)(drag_value.as_ref(), cursor_offset, window, cx);
2293 cx.active_drag = Some(AnyDrag {
2294 view: drag,
2295 value: drag_value,
2296 cursor_offset,
2297 cursor_style: drag_cursor_style,
2298 });
2299 pending_mouse_down.take();
2300 window.refresh();
2301 cx.stop_propagation();
2302 }
2303 }
2304 });
2305
2306 if is_focused {
2307 // Press enter, space to trigger click, when the element is focused.
2308 window.on_key_event({
2309 let click_listeners = click_listeners.clone();
2310 let hitbox = hitbox.clone();
2311 move |event: &KeyUpEvent, phase, window, cx| {
2312 if phase.bubble() && !window.default_prevented() {
2313 let stroke = &event.keystroke;
2314 let keyboard_button = if stroke.key.eq("enter") {
2315 Some(KeyboardButton::Enter)
2316 } else if stroke.key.eq("space") {
2317 Some(KeyboardButton::Space)
2318 } else {
2319 None
2320 };
2321
2322 if let Some(button) = keyboard_button
2323 && !stroke.modifiers.modified()
2324 {
2325 let click_event = ClickEvent::Keyboard(KeyboardClickEvent {
2326 button,
2327 bounds: hitbox.bounds,
2328 });
2329
2330 for listener in &click_listeners {
2331 listener(&click_event, window, cx);
2332 }
2333 }
2334 }
2335 }
2336 });
2337 }
2338
2339 window.on_mouse_event({
2340 let mut captured_mouse_down = None;
2341 let hitbox = hitbox.clone();
2342 move |event: &MouseUpEvent, phase, window, cx| match phase {
2343 // Clear the pending mouse down during the capture phase,
2344 // so that it happens even if another event handler stops
2345 // propagation.
2346 DispatchPhase::Capture => {
2347 let mut pending_mouse_down = pending_mouse_down.borrow_mut();
2348 if pending_mouse_down.is_some() && hitbox.is_hovered(window) {
2349 captured_mouse_down = pending_mouse_down.take();
2350 window.refresh();
2351 } else if pending_mouse_down.is_some() {
2352 // Clear the pending mouse down event (without firing click handlers)
2353 // if the hitbox is not being hovered.
2354 // This avoids dragging elements that changed their position
2355 // immediately after being clicked.
2356 // See https://github.com/zed-industries/zed/issues/24600 for more details
2357 pending_mouse_down.take();
2358 window.refresh();
2359 }
2360 }
2361 // Fire click handlers during the bubble phase.
2362 DispatchPhase::Bubble => {
2363 if let Some(mouse_down) = captured_mouse_down.take() {
2364 let mouse_click = ClickEvent::Mouse(MouseClickEvent {
2365 down: mouse_down,
2366 up: event.clone(),
2367 });
2368 for listener in &click_listeners {
2369 listener(&mouse_click, window, cx);
2370 }
2371 }
2372 }
2373 }
2374 });
2375 }
2376
2377 if let Some(hover_listener) = self.hover_listener.take() {
2378 let hitbox = hitbox.clone();
2379 let was_hovered = element_state
2380 .hover_listener_state
2381 .get_or_insert_with(Default::default)
2382 .clone();
2383 let has_mouse_down = element_state
2384 .pending_mouse_down
2385 .get_or_insert_with(Default::default)
2386 .clone();
2387
2388 window.on_mouse_event(move |_: &MouseMoveEvent, phase, window, cx| {
2389 if phase != DispatchPhase::Bubble {
2390 return;
2391 }
2392 let is_hovered = has_mouse_down.borrow().is_none()
2393 && !cx.has_active_drag()
2394 && hitbox.is_hovered(window);
2395 let mut was_hovered = was_hovered.borrow_mut();
2396
2397 if is_hovered != *was_hovered {
2398 *was_hovered = is_hovered;
2399 drop(was_hovered);
2400
2401 hover_listener(&is_hovered, window, cx);
2402 }
2403 });
2404 }
2405
2406 if let Some(tooltip_builder) = self.tooltip_builder.take() {
2407 let active_tooltip = element_state
2408 .active_tooltip
2409 .get_or_insert_with(Default::default)
2410 .clone();
2411 let pending_mouse_down = element_state
2412 .pending_mouse_down
2413 .get_or_insert_with(Default::default)
2414 .clone();
2415
2416 let tooltip_is_hoverable = tooltip_builder.hoverable;
2417 let build_tooltip = Rc::new(move |window: &mut Window, cx: &mut App| {
2418 Some(((tooltip_builder.build)(window, cx), tooltip_is_hoverable))
2419 });
2420 // Use bounds instead of testing hitbox since this is called during prepaint.
2421 let check_is_hovered_during_prepaint = Rc::new({
2422 let pending_mouse_down = pending_mouse_down.clone();
2423 let source_bounds = hitbox.bounds;
2424 move |window: &Window| {
2425 pending_mouse_down.borrow().is_none()
2426 && source_bounds.contains(&window.mouse_position())
2427 }
2428 });
2429 let check_is_hovered = Rc::new({
2430 let hitbox = hitbox.clone();
2431 move |window: &Window| {
2432 pending_mouse_down.borrow().is_none() && hitbox.is_hovered(window)
2433 }
2434 });
2435 register_tooltip_mouse_handlers(
2436 &active_tooltip,
2437 self.tooltip_id,
2438 build_tooltip,
2439 check_is_hovered,
2440 check_is_hovered_during_prepaint,
2441 window,
2442 );
2443 }
2444
2445 let active_state = element_state
2446 .clicked_state
2447 .get_or_insert_with(Default::default)
2448 .clone();
2449 if active_state.borrow().is_clicked() {
2450 window.on_mouse_event(move |_: &MouseUpEvent, phase, window, _cx| {
2451 if phase == DispatchPhase::Capture {
2452 *active_state.borrow_mut() = ElementClickedState::default();
2453 window.refresh();
2454 }
2455 });
2456 } else {
2457 let active_group_hitbox = self
2458 .group_active_style
2459 .as_ref()
2460 .and_then(|group_active| GroupHitboxes::get(&group_active.group, cx));
2461 let hitbox = hitbox.clone();
2462 window.on_mouse_event(move |_: &MouseDownEvent, phase, window, _cx| {
2463 if phase == DispatchPhase::Bubble && !window.default_prevented() {
2464 let group_hovered = active_group_hitbox
2465 .is_some_and(|group_hitbox_id| group_hitbox_id.is_hovered(window));
2466 let element_hovered = hitbox.is_hovered(window);
2467 if group_hovered || element_hovered {
2468 *active_state.borrow_mut() = ElementClickedState {
2469 group: group_hovered,
2470 element: element_hovered,
2471 };
2472 window.refresh();
2473 }
2474 }
2475 });
2476 }
2477 }
2478 }
2479
2480 fn paint_keyboard_listeners(&mut self, window: &mut Window, _cx: &mut App) {
2481 let key_down_listeners = mem::take(&mut self.key_down_listeners);
2482 let key_up_listeners = mem::take(&mut self.key_up_listeners);
2483 let modifiers_changed_listeners = mem::take(&mut self.modifiers_changed_listeners);
2484 let action_listeners = mem::take(&mut self.action_listeners);
2485 if let Some(context) = self.key_context.clone() {
2486 window.set_key_context(context);
2487 }
2488
2489 for listener in key_down_listeners {
2490 window.on_key_event(move |event: &KeyDownEvent, phase, window, cx| {
2491 listener(event, phase, window, cx);
2492 })
2493 }
2494
2495 for listener in key_up_listeners {
2496 window.on_key_event(move |event: &KeyUpEvent, phase, window, cx| {
2497 listener(event, phase, window, cx);
2498 })
2499 }
2500
2501 for listener in modifiers_changed_listeners {
2502 window.on_modifiers_changed(move |event: &ModifiersChangedEvent, window, cx| {
2503 listener(event, window, cx);
2504 })
2505 }
2506
2507 for (action_type, listener) in action_listeners {
2508 window.on_action(action_type, listener)
2509 }
2510 }
2511
2512 fn paint_hover_group_handler(&self, window: &mut Window, cx: &mut App) {
2513 let group_hitbox = self
2514 .group_hover_style
2515 .as_ref()
2516 .and_then(|group_hover| GroupHitboxes::get(&group_hover.group, cx));
2517
2518 if let Some(group_hitbox) = group_hitbox {
2519 let was_hovered = group_hitbox.is_hovered(window);
2520 let current_view = window.current_view();
2521 window.on_mouse_event(move |_: &MouseMoveEvent, phase, window, cx| {
2522 let hovered = group_hitbox.is_hovered(window);
2523 if phase == DispatchPhase::Capture && hovered != was_hovered {
2524 cx.notify(current_view);
2525 }
2526 });
2527 }
2528 }
2529
2530 fn paint_scroll_listener(
2531 &self,
2532 hitbox: &Hitbox,
2533 style: &Style,
2534 window: &mut Window,
2535 _cx: &mut App,
2536 ) {
2537 if let Some(scroll_offset) = self.scroll_offset.clone() {
2538 let overflow = style.overflow;
2539 let allow_concurrent_scroll = style.allow_concurrent_scroll;
2540 let restrict_scroll_to_axis = style.restrict_scroll_to_axis;
2541 let line_height = window.line_height();
2542 let hitbox = hitbox.clone();
2543 let current_view = window.current_view();
2544 window.on_mouse_event(move |event: &ScrollWheelEvent, phase, window, cx| {
2545 if phase == DispatchPhase::Bubble && hitbox.should_handle_scroll(window) {
2546 let mut scroll_offset = scroll_offset.borrow_mut();
2547 let old_scroll_offset = *scroll_offset;
2548 let delta = event.delta.pixel_delta(line_height);
2549
2550 let mut delta_x = Pixels::ZERO;
2551 if overflow.x == Overflow::Scroll {
2552 if !delta.x.is_zero() {
2553 delta_x = delta.x;
2554 } else if !restrict_scroll_to_axis && overflow.y != Overflow::Scroll {
2555 delta_x = delta.y;
2556 }
2557 }
2558 let mut delta_y = Pixels::ZERO;
2559 if overflow.y == Overflow::Scroll {
2560 if !delta.y.is_zero() {
2561 delta_y = delta.y;
2562 } else if !restrict_scroll_to_axis && overflow.x != Overflow::Scroll {
2563 delta_y = delta.x;
2564 }
2565 }
2566 if !allow_concurrent_scroll && !delta_x.is_zero() && !delta_y.is_zero() {
2567 if delta_x.abs() > delta_y.abs() {
2568 delta_y = Pixels::ZERO;
2569 } else {
2570 delta_x = Pixels::ZERO;
2571 }
2572 }
2573 scroll_offset.y += delta_y;
2574 scroll_offset.x += delta_x;
2575 if *scroll_offset != old_scroll_offset {
2576 cx.notify(current_view);
2577 }
2578 }
2579 });
2580 }
2581 }
2582
2583 /// Compute the visual style for this element, based on the current bounds and the element's state.
2584 pub fn compute_style(
2585 &self,
2586 global_id: Option<&GlobalElementId>,
2587 hitbox: Option<&Hitbox>,
2588 window: &mut Window,
2589 cx: &mut App,
2590 ) -> Style {
2591 window.with_optional_element_state(global_id, |element_state, window| {
2592 let mut element_state =
2593 element_state.map(|element_state| element_state.unwrap_or_default());
2594 let style = self.compute_style_internal(hitbox, element_state.as_mut(), window, cx);
2595 (style, element_state)
2596 })
2597 }
2598
2599 /// Called from internal methods that have already called with_element_state.
2600 fn compute_style_internal(
2601 &self,
2602 hitbox: Option<&Hitbox>,
2603 element_state: Option<&mut InteractiveElementState>,
2604 window: &mut Window,
2605 cx: &mut App,
2606 ) -> Style {
2607 let mut style = Style::default();
2608 style.refine(&self.base_style);
2609
2610 if let Some(focus_handle) = self.tracked_focus_handle.as_ref() {
2611 if let Some(in_focus_style) = self.in_focus_style.as_ref()
2612 && focus_handle.within_focused(window, cx)
2613 {
2614 style.refine(in_focus_style);
2615 }
2616
2617 if let Some(focus_style) = self.focus_style.as_ref()
2618 && focus_handle.is_focused(window)
2619 {
2620 style.refine(focus_style);
2621 }
2622
2623 if let Some(focus_visible_style) = self.focus_visible_style.as_ref()
2624 && focus_handle.is_focused(window)
2625 && window.last_input_was_keyboard()
2626 {
2627 style.refine(focus_visible_style);
2628 }
2629 }
2630
2631 if !cx.has_active_drag() {
2632 if let Some(group_hover) = self.group_hover_style.as_ref() {
2633 let is_group_hovered =
2634 if let Some(group_hitbox_id) = GroupHitboxes::get(&group_hover.group, cx) {
2635 group_hitbox_id.is_hovered(window)
2636 } else if let Some(element_state) = element_state.as_ref() {
2637 element_state
2638 .hover_state
2639 .as_ref()
2640 .map(|state| state.borrow().group)
2641 .unwrap_or(false)
2642 } else {
2643 false
2644 };
2645
2646 if is_group_hovered {
2647 style.refine(&group_hover.style);
2648 }
2649 }
2650
2651 if let Some(hover_style) = self.hover_style.as_ref() {
2652 let is_hovered = if let Some(hitbox) = hitbox {
2653 hitbox.is_hovered(window)
2654 } else if let Some(element_state) = element_state.as_ref() {
2655 element_state
2656 .hover_state
2657 .as_ref()
2658 .map(|state| state.borrow().element)
2659 .unwrap_or(false)
2660 } else {
2661 false
2662 };
2663
2664 if is_hovered {
2665 style.refine(hover_style);
2666 }
2667 }
2668 }
2669
2670 if let Some(hitbox) = hitbox {
2671 if let Some(drag) = cx.active_drag.take() {
2672 let mut can_drop = true;
2673 if let Some(can_drop_predicate) = &self.can_drop_predicate {
2674 can_drop = can_drop_predicate(drag.value.as_ref(), window, cx);
2675 }
2676
2677 if can_drop {
2678 for (state_type, group_drag_style) in &self.group_drag_over_styles {
2679 if let Some(group_hitbox_id) =
2680 GroupHitboxes::get(&group_drag_style.group, cx)
2681 && *state_type == drag.value.as_ref().type_id()
2682 && group_hitbox_id.is_hovered(window)
2683 {
2684 style.refine(&group_drag_style.style);
2685 }
2686 }
2687
2688 for (state_type, build_drag_over_style) in &self.drag_over_styles {
2689 if *state_type == drag.value.as_ref().type_id() && hitbox.is_hovered(window)
2690 {
2691 style.refine(&build_drag_over_style(drag.value.as_ref(), window, cx));
2692 }
2693 }
2694 }
2695
2696 style.mouse_cursor = drag.cursor_style;
2697 cx.active_drag = Some(drag);
2698 }
2699 }
2700
2701 if let Some(element_state) = element_state {
2702 let clicked_state = element_state
2703 .clicked_state
2704 .get_or_insert_with(Default::default)
2705 .borrow();
2706 if clicked_state.group
2707 && let Some(group) = self.group_active_style.as_ref()
2708 {
2709 style.refine(&group.style)
2710 }
2711
2712 if let Some(active_style) = self.active_style.as_ref()
2713 && clicked_state.element
2714 {
2715 style.refine(active_style)
2716 }
2717 }
2718
2719 style
2720 }
2721}
2722
2723/// The per-frame state of an interactive element. Used for tracking stateful interactions like clicks
2724/// and scroll offsets.
2725#[derive(Default)]
2726pub struct InteractiveElementState {
2727 pub(crate) focus_handle: Option<FocusHandle>,
2728 pub(crate) clicked_state: Option<Rc<RefCell<ElementClickedState>>>,
2729 pub(crate) hover_state: Option<Rc<RefCell<ElementHoverState>>>,
2730 pub(crate) hover_listener_state: Option<Rc<RefCell<bool>>>,
2731 pub(crate) pending_mouse_down: Option<Rc<RefCell<Option<MouseDownEvent>>>>,
2732 pub(crate) scroll_offset: Option<Rc<RefCell<Point<Pixels>>>>,
2733 pub(crate) active_tooltip: Option<Rc<RefCell<Option<ActiveTooltip>>>>,
2734}
2735
2736/// Whether or not the element or a group that contains it is clicked by the mouse.
2737#[derive(Copy, Clone, Default, Eq, PartialEq)]
2738pub struct ElementClickedState {
2739 /// True if this element's group has been clicked, false otherwise
2740 pub group: bool,
2741
2742 /// True if this element has been clicked, false otherwise
2743 pub element: bool,
2744}
2745
2746impl ElementClickedState {
2747 fn is_clicked(&self) -> bool {
2748 self.group || self.element
2749 }
2750}
2751
2752/// Whether or not the element or a group that contains it is hovered.
2753#[derive(Copy, Clone, Default, Eq, PartialEq)]
2754pub struct ElementHoverState {
2755 /// True if this element's group is hovered, false otherwise
2756 pub group: bool,
2757
2758 /// True if this element is hovered, false otherwise
2759 pub element: bool,
2760}
2761
2762pub(crate) enum ActiveTooltip {
2763 /// Currently delaying before showing the tooltip.
2764 WaitingForShow { _task: Task<()> },
2765 /// Tooltip is visible, element was hovered or for hoverable tooltips, the tooltip was hovered.
2766 Visible {
2767 tooltip: AnyTooltip,
2768 is_hoverable: bool,
2769 },
2770 /// Tooltip is visible and hoverable, but the mouse is no longer hovering. Currently delaying
2771 /// before hiding it.
2772 WaitingForHide {
2773 tooltip: AnyTooltip,
2774 _task: Task<()>,
2775 },
2776}
2777
2778pub(crate) fn clear_active_tooltip(
2779 active_tooltip: &Rc<RefCell<Option<ActiveTooltip>>>,
2780 window: &mut Window,
2781) {
2782 match active_tooltip.borrow_mut().take() {
2783 None => {}
2784 Some(ActiveTooltip::WaitingForShow { .. }) => {}
2785 Some(ActiveTooltip::Visible { .. }) => window.refresh(),
2786 Some(ActiveTooltip::WaitingForHide { .. }) => window.refresh(),
2787 }
2788}
2789
2790pub(crate) fn clear_active_tooltip_if_not_hoverable(
2791 active_tooltip: &Rc<RefCell<Option<ActiveTooltip>>>,
2792 window: &mut Window,
2793) {
2794 let should_clear = match active_tooltip.borrow().as_ref() {
2795 None => false,
2796 Some(ActiveTooltip::WaitingForShow { .. }) => false,
2797 Some(ActiveTooltip::Visible { is_hoverable, .. }) => !is_hoverable,
2798 Some(ActiveTooltip::WaitingForHide { .. }) => false,
2799 };
2800 if should_clear {
2801 active_tooltip.borrow_mut().take();
2802 window.refresh();
2803 }
2804}
2805
2806pub(crate) fn set_tooltip_on_window(
2807 active_tooltip: &Rc<RefCell<Option<ActiveTooltip>>>,
2808 window: &mut Window,
2809) -> Option<TooltipId> {
2810 let tooltip = match active_tooltip.borrow().as_ref() {
2811 None => return None,
2812 Some(ActiveTooltip::WaitingForShow { .. }) => return None,
2813 Some(ActiveTooltip::Visible { tooltip, .. }) => tooltip.clone(),
2814 Some(ActiveTooltip::WaitingForHide { tooltip, .. }) => tooltip.clone(),
2815 };
2816 Some(window.set_tooltip(tooltip))
2817}
2818
2819pub(crate) fn register_tooltip_mouse_handlers(
2820 active_tooltip: &Rc<RefCell<Option<ActiveTooltip>>>,
2821 tooltip_id: Option<TooltipId>,
2822 build_tooltip: Rc<dyn Fn(&mut Window, &mut App) -> Option<(AnyView, bool)>>,
2823 check_is_hovered: Rc<dyn Fn(&Window) -> bool>,
2824 check_is_hovered_during_prepaint: Rc<dyn Fn(&Window) -> bool>,
2825 window: &mut Window,
2826) {
2827 window.on_mouse_event({
2828 let active_tooltip = active_tooltip.clone();
2829 let build_tooltip = build_tooltip.clone();
2830 let check_is_hovered = check_is_hovered.clone();
2831 move |_: &MouseMoveEvent, phase, window, cx| {
2832 handle_tooltip_mouse_move(
2833 &active_tooltip,
2834 &build_tooltip,
2835 &check_is_hovered,
2836 &check_is_hovered_during_prepaint,
2837 phase,
2838 window,
2839 cx,
2840 )
2841 }
2842 });
2843
2844 window.on_mouse_event({
2845 let active_tooltip = active_tooltip.clone();
2846 move |_: &MouseDownEvent, _phase, window: &mut Window, _cx| {
2847 if !tooltip_id.is_some_and(|tooltip_id| tooltip_id.is_hovered(window)) {
2848 clear_active_tooltip_if_not_hoverable(&active_tooltip, window);
2849 }
2850 }
2851 });
2852
2853 window.on_mouse_event({
2854 let active_tooltip = active_tooltip.clone();
2855 move |_: &ScrollWheelEvent, _phase, window: &mut Window, _cx| {
2856 if !tooltip_id.is_some_and(|tooltip_id| tooltip_id.is_hovered(window)) {
2857 clear_active_tooltip_if_not_hoverable(&active_tooltip, window);
2858 }
2859 }
2860 });
2861}
2862
2863/// Handles displaying tooltips when an element is hovered.
2864///
2865/// The mouse hovering logic also relies on being called from window prepaint in order to handle the
2866/// case where the element the tooltip is on is not rendered - in that case its mouse listeners are
2867/// also not registered. During window prepaint, the hitbox information is not available, so
2868/// `check_is_hovered_during_prepaint` is used which bases the check off of the absolute bounds of
2869/// the element.
2870///
2871/// TODO: There's a minor bug due to the use of absolute bounds while checking during prepaint - it
2872/// does not know if the hitbox is occluded. In the case where a tooltip gets displayed and then
2873/// gets occluded after display, it will stick around until the mouse exits the hover bounds.
2874fn handle_tooltip_mouse_move(
2875 active_tooltip: &Rc<RefCell<Option<ActiveTooltip>>>,
2876 build_tooltip: &Rc<dyn Fn(&mut Window, &mut App) -> Option<(AnyView, bool)>>,
2877 check_is_hovered: &Rc<dyn Fn(&Window) -> bool>,
2878 check_is_hovered_during_prepaint: &Rc<dyn Fn(&Window) -> bool>,
2879 phase: DispatchPhase,
2880 window: &mut Window,
2881 cx: &mut App,
2882) {
2883 // Separates logic for what mutation should occur from applying it, to avoid overlapping
2884 // RefCell borrows.
2885 enum Action {
2886 None,
2887 CancelShow,
2888 ScheduleShow,
2889 }
2890
2891 let action = match active_tooltip.borrow().as_ref() {
2892 None => {
2893 let is_hovered = check_is_hovered(window);
2894 if is_hovered && phase.bubble() {
2895 Action::ScheduleShow
2896 } else {
2897 Action::None
2898 }
2899 }
2900 Some(ActiveTooltip::WaitingForShow { .. }) => {
2901 let is_hovered = check_is_hovered(window);
2902 if is_hovered {
2903 Action::None
2904 } else {
2905 Action::CancelShow
2906 }
2907 }
2908 // These are handled in check_visible_and_update.
2909 Some(ActiveTooltip::Visible { .. }) | Some(ActiveTooltip::WaitingForHide { .. }) => {
2910 Action::None
2911 }
2912 };
2913
2914 match action {
2915 Action::None => {}
2916 Action::CancelShow => {
2917 // Cancel waiting to show tooltip when it is no longer hovered.
2918 active_tooltip.borrow_mut().take();
2919 }
2920 Action::ScheduleShow => {
2921 let delayed_show_task = window.spawn(cx, {
2922 let active_tooltip = active_tooltip.clone();
2923 let build_tooltip = build_tooltip.clone();
2924 let check_is_hovered_during_prepaint = check_is_hovered_during_prepaint.clone();
2925 async move |cx| {
2926 cx.background_executor().timer(TOOLTIP_SHOW_DELAY).await;
2927 cx.update(|window, cx| {
2928 let new_tooltip =
2929 build_tooltip(window, cx).map(|(view, tooltip_is_hoverable)| {
2930 let active_tooltip = active_tooltip.clone();
2931 ActiveTooltip::Visible {
2932 tooltip: AnyTooltip {
2933 view,
2934 mouse_position: window.mouse_position(),
2935 check_visible_and_update: Rc::new(
2936 move |tooltip_bounds, window, cx| {
2937 handle_tooltip_check_visible_and_update(
2938 &active_tooltip,
2939 tooltip_is_hoverable,
2940 &check_is_hovered_during_prepaint,
2941 tooltip_bounds,
2942 window,
2943 cx,
2944 )
2945 },
2946 ),
2947 },
2948 is_hoverable: tooltip_is_hoverable,
2949 }
2950 });
2951 *active_tooltip.borrow_mut() = new_tooltip;
2952 window.refresh();
2953 })
2954 .ok();
2955 }
2956 });
2957 active_tooltip
2958 .borrow_mut()
2959 .replace(ActiveTooltip::WaitingForShow {
2960 _task: delayed_show_task,
2961 });
2962 }
2963 }
2964}
2965
2966/// Returns a callback which will be called by window prepaint to update tooltip visibility. The
2967/// purpose of doing this logic here instead of the mouse move handler is that the mouse move
2968/// handler won't get called when the element is not painted (e.g. via use of `visible_on_hover`).
2969fn handle_tooltip_check_visible_and_update(
2970 active_tooltip: &Rc<RefCell<Option<ActiveTooltip>>>,
2971 tooltip_is_hoverable: bool,
2972 check_is_hovered: &Rc<dyn Fn(&Window) -> bool>,
2973 tooltip_bounds: Bounds<Pixels>,
2974 window: &mut Window,
2975 cx: &mut App,
2976) -> bool {
2977 // Separates logic for what mutation should occur from applying it, to avoid overlapping RefCell
2978 // borrows.
2979 enum Action {
2980 None,
2981 Hide,
2982 ScheduleHide(AnyTooltip),
2983 CancelHide(AnyTooltip),
2984 }
2985
2986 let is_hovered = check_is_hovered(window)
2987 || (tooltip_is_hoverable && tooltip_bounds.contains(&window.mouse_position()));
2988 let action = match active_tooltip.borrow().as_ref() {
2989 Some(ActiveTooltip::Visible { tooltip, .. }) => {
2990 if is_hovered {
2991 Action::None
2992 } else {
2993 if tooltip_is_hoverable {
2994 Action::ScheduleHide(tooltip.clone())
2995 } else {
2996 Action::Hide
2997 }
2998 }
2999 }
3000 Some(ActiveTooltip::WaitingForHide { tooltip, .. }) => {
3001 if is_hovered {
3002 Action::CancelHide(tooltip.clone())
3003 } else {
3004 Action::None
3005 }
3006 }
3007 None | Some(ActiveTooltip::WaitingForShow { .. }) => Action::None,
3008 };
3009
3010 match action {
3011 Action::None => {}
3012 Action::Hide => clear_active_tooltip(active_tooltip, window),
3013 Action::ScheduleHide(tooltip) => {
3014 let delayed_hide_task = window.spawn(cx, {
3015 let active_tooltip = active_tooltip.clone();
3016 async move |cx| {
3017 cx.background_executor()
3018 .timer(HOVERABLE_TOOLTIP_HIDE_DELAY)
3019 .await;
3020 if active_tooltip.borrow_mut().take().is_some() {
3021 cx.update(|window, _cx| window.refresh()).ok();
3022 }
3023 }
3024 });
3025 active_tooltip
3026 .borrow_mut()
3027 .replace(ActiveTooltip::WaitingForHide {
3028 tooltip,
3029 _task: delayed_hide_task,
3030 });
3031 }
3032 Action::CancelHide(tooltip) => {
3033 // Cancel waiting to hide tooltip when it becomes hovered.
3034 active_tooltip.borrow_mut().replace(ActiveTooltip::Visible {
3035 tooltip,
3036 is_hoverable: true,
3037 });
3038 }
3039 }
3040
3041 active_tooltip.borrow().is_some()
3042}
3043
3044#[derive(Default)]
3045pub(crate) struct GroupHitboxes(HashMap<SharedString, SmallVec<[HitboxId; 1]>>);
3046
3047impl Global for GroupHitboxes {}
3048
3049impl GroupHitboxes {
3050 pub fn get(name: &SharedString, cx: &mut App) -> Option<HitboxId> {
3051 cx.default_global::<Self>()
3052 .0
3053 .get(name)
3054 .and_then(|bounds_stack| bounds_stack.last())
3055 .cloned()
3056 }
3057
3058 pub fn push(name: SharedString, hitbox_id: HitboxId, cx: &mut App) {
3059 cx.default_global::<Self>()
3060 .0
3061 .entry(name)
3062 .or_default()
3063 .push(hitbox_id);
3064 }
3065
3066 pub fn pop(name: &SharedString, cx: &mut App) {
3067 cx.default_global::<Self>().0.get_mut(name).unwrap().pop();
3068 }
3069}
3070
3071/// A wrapper around an element that can store state, produced after assigning an ElementId.
3072pub struct Stateful<E> {
3073 pub(crate) element: E,
3074}
3075
3076impl<E> Styled for Stateful<E>
3077where
3078 E: Styled,
3079{
3080 fn style(&mut self) -> &mut StyleRefinement {
3081 self.element.style()
3082 }
3083}
3084
3085impl<E> StatefulInteractiveElement for Stateful<E>
3086where
3087 E: Element,
3088 Self: InteractiveElement,
3089{
3090}
3091
3092impl<E> InteractiveElement for Stateful<E>
3093where
3094 E: InteractiveElement,
3095{
3096 fn interactivity(&mut self) -> &mut Interactivity {
3097 self.element.interactivity()
3098 }
3099}
3100
3101impl<E> Element for Stateful<E>
3102where
3103 E: Element,
3104{
3105 type RequestLayoutState = E::RequestLayoutState;
3106 type PrepaintState = E::PrepaintState;
3107
3108 fn id(&self) -> Option<ElementId> {
3109 self.element.id()
3110 }
3111
3112 fn source_location(&self) -> Option<&'static core::panic::Location<'static>> {
3113 self.element.source_location()
3114 }
3115
3116 fn request_layout(
3117 &mut self,
3118 id: Option<&GlobalElementId>,
3119 inspector_id: Option<&InspectorElementId>,
3120 window: &mut Window,
3121 cx: &mut App,
3122 ) -> (LayoutId, Self::RequestLayoutState) {
3123 self.element.request_layout(id, inspector_id, window, cx)
3124 }
3125
3126 fn prepaint(
3127 &mut self,
3128 id: Option<&GlobalElementId>,
3129 inspector_id: Option<&InspectorElementId>,
3130 bounds: Bounds<Pixels>,
3131 state: &mut Self::RequestLayoutState,
3132 window: &mut Window,
3133 cx: &mut App,
3134 ) -> E::PrepaintState {
3135 self.element
3136 .prepaint(id, inspector_id, bounds, state, window, cx)
3137 }
3138
3139 fn paint(
3140 &mut self,
3141 id: Option<&GlobalElementId>,
3142 inspector_id: Option<&InspectorElementId>,
3143 bounds: Bounds<Pixels>,
3144 request_layout: &mut Self::RequestLayoutState,
3145 prepaint: &mut Self::PrepaintState,
3146 window: &mut Window,
3147 cx: &mut App,
3148 ) {
3149 self.element.paint(
3150 id,
3151 inspector_id,
3152 bounds,
3153 request_layout,
3154 prepaint,
3155 window,
3156 cx,
3157 );
3158 }
3159}
3160
3161impl<E> IntoElement for Stateful<E>
3162where
3163 E: Element,
3164{
3165 type Element = Self;
3166
3167 fn into_element(self) -> Self::Element {
3168 self
3169 }
3170}
3171
3172impl<E> ParentElement for Stateful<E>
3173where
3174 E: ParentElement,
3175{
3176 fn extend(&mut self, elements: impl IntoIterator<Item = AnyElement>) {
3177 self.element.extend(elements)
3178 }
3179}
3180
3181/// Represents an element that can be scrolled *to* in its parent element.
3182/// Contrary to [ScrollHandle::scroll_to_active_item], an anchored element does not have to be an immediate child of the parent.
3183#[derive(Clone)]
3184pub struct ScrollAnchor {
3185 handle: ScrollHandle,
3186 last_origin: Rc<RefCell<Point<Pixels>>>,
3187}
3188
3189impl ScrollAnchor {
3190 /// Creates a [ScrollAnchor] associated with a given [ScrollHandle].
3191 pub fn for_handle(handle: ScrollHandle) -> Self {
3192 Self {
3193 handle,
3194 last_origin: Default::default(),
3195 }
3196 }
3197 /// Request scroll to this item on the next frame.
3198 pub fn scroll_to(&self, window: &mut Window, _cx: &mut App) {
3199 let this = self.clone();
3200
3201 window.on_next_frame(move |_, _| {
3202 let viewport_bounds = this.handle.bounds();
3203 let self_bounds = *this.last_origin.borrow();
3204 this.handle.set_offset(viewport_bounds.origin - self_bounds);
3205 });
3206 }
3207}
3208
3209#[derive(Default, Debug)]
3210struct ScrollHandleState {
3211 offset: Rc<RefCell<Point<Pixels>>>,
3212 bounds: Bounds<Pixels>,
3213 max_offset: Size<Pixels>,
3214 child_bounds: Vec<Bounds<Pixels>>,
3215 scroll_to_bottom: bool,
3216 overflow: Point<Overflow>,
3217 active_item: Option<ScrollActiveItem>,
3218}
3219
3220#[derive(Default, Debug, Clone, Copy)]
3221struct ScrollActiveItem {
3222 index: usize,
3223 strategy: ScrollStrategy,
3224}
3225
3226#[derive(Default, Debug, Clone, Copy)]
3227enum ScrollStrategy {
3228 #[default]
3229 FirstVisible,
3230 Top,
3231}
3232
3233/// A handle to the scrollable aspects of an element.
3234/// Used for accessing scroll state, like the current scroll offset,
3235/// and for mutating the scroll state, like scrolling to a specific child.
3236#[derive(Clone, Debug)]
3237pub struct ScrollHandle(Rc<RefCell<ScrollHandleState>>);
3238
3239impl Default for ScrollHandle {
3240 fn default() -> Self {
3241 Self::new()
3242 }
3243}
3244
3245impl ScrollHandle {
3246 /// Construct a new scroll handle.
3247 pub fn new() -> Self {
3248 Self(Rc::default())
3249 }
3250
3251 /// Get the current scroll offset.
3252 pub fn offset(&self) -> Point<Pixels> {
3253 *self.0.borrow().offset.borrow()
3254 }
3255
3256 /// Get the maximum scroll offset.
3257 pub fn max_offset(&self) -> Size<Pixels> {
3258 self.0.borrow().max_offset
3259 }
3260
3261 /// Get the top child that's scrolled into view.
3262 pub fn top_item(&self) -> usize {
3263 let state = self.0.borrow();
3264 let top = state.bounds.top() - state.offset.borrow().y;
3265
3266 match state.child_bounds.binary_search_by(|bounds| {
3267 if top < bounds.top() {
3268 Ordering::Greater
3269 } else if top > bounds.bottom() {
3270 Ordering::Less
3271 } else {
3272 Ordering::Equal
3273 }
3274 }) {
3275 Ok(ix) => ix,
3276 Err(ix) => ix.min(state.child_bounds.len().saturating_sub(1)),
3277 }
3278 }
3279
3280 /// Get the bottom child that's scrolled into view.
3281 pub fn bottom_item(&self) -> usize {
3282 let state = self.0.borrow();
3283 let bottom = state.bounds.bottom() - state.offset.borrow().y;
3284
3285 match state.child_bounds.binary_search_by(|bounds| {
3286 if bottom < bounds.top() {
3287 Ordering::Greater
3288 } else if bottom > bounds.bottom() {
3289 Ordering::Less
3290 } else {
3291 Ordering::Equal
3292 }
3293 }) {
3294 Ok(ix) => ix,
3295 Err(ix) => ix.min(state.child_bounds.len().saturating_sub(1)),
3296 }
3297 }
3298
3299 /// Return the bounds into which this child is painted
3300 pub fn bounds(&self) -> Bounds<Pixels> {
3301 self.0.borrow().bounds
3302 }
3303
3304 /// Get the bounds for a specific child.
3305 pub fn bounds_for_item(&self, ix: usize) -> Option<Bounds<Pixels>> {
3306 self.0.borrow().child_bounds.get(ix).cloned()
3307 }
3308
3309 /// Update [ScrollHandleState]'s active item for scrolling to in prepaint
3310 pub fn scroll_to_item(&self, ix: usize) {
3311 let mut state = self.0.borrow_mut();
3312 state.active_item = Some(ScrollActiveItem {
3313 index: ix,
3314 strategy: ScrollStrategy::default(),
3315 });
3316 }
3317
3318 /// Update [ScrollHandleState]'s active item for scrolling to in prepaint
3319 /// This scrolls the minimal amount to ensure that the child is the first visible element
3320 pub fn scroll_to_top_of_item(&self, ix: usize) {
3321 let mut state = self.0.borrow_mut();
3322 state.active_item = Some(ScrollActiveItem {
3323 index: ix,
3324 strategy: ScrollStrategy::Top,
3325 });
3326 }
3327
3328 /// Scrolls the minimal amount to either ensure that the child is
3329 /// fully visible or the top element of the view depends on the
3330 /// scroll strategy
3331 fn scroll_to_active_item(&self) {
3332 let mut state = self.0.borrow_mut();
3333
3334 let Some(active_item) = state.active_item else {
3335 return;
3336 };
3337
3338 let active_item = match state.child_bounds.get(active_item.index) {
3339 Some(bounds) => {
3340 let mut scroll_offset = state.offset.borrow_mut();
3341
3342 match active_item.strategy {
3343 ScrollStrategy::FirstVisible => {
3344 if state.overflow.y == Overflow::Scroll {
3345 let child_height = bounds.size.height;
3346 let viewport_height = state.bounds.size.height;
3347 if child_height > viewport_height {
3348 scroll_offset.y = state.bounds.top() - bounds.top();
3349 } else if bounds.top() + scroll_offset.y < state.bounds.top() {
3350 scroll_offset.y = state.bounds.top() - bounds.top();
3351 } else if bounds.bottom() + scroll_offset.y > state.bounds.bottom() {
3352 scroll_offset.y = state.bounds.bottom() - bounds.bottom();
3353 }
3354 }
3355 }
3356 ScrollStrategy::Top => {
3357 scroll_offset.y = state.bounds.top() - bounds.top();
3358 }
3359 }
3360
3361 if state.overflow.x == Overflow::Scroll {
3362 let child_width = bounds.size.width;
3363 let viewport_width = state.bounds.size.width;
3364 if child_width > viewport_width {
3365 scroll_offset.x = state.bounds.left() - bounds.left();
3366 } else if bounds.left() + scroll_offset.x < state.bounds.left() {
3367 scroll_offset.x = state.bounds.left() - bounds.left();
3368 } else if bounds.right() + scroll_offset.x > state.bounds.right() {
3369 scroll_offset.x = state.bounds.right() - bounds.right();
3370 }
3371 }
3372 None
3373 }
3374 None => Some(active_item),
3375 };
3376 state.active_item = active_item;
3377 }
3378
3379 /// Scrolls to the bottom.
3380 pub fn scroll_to_bottom(&self) {
3381 let mut state = self.0.borrow_mut();
3382 state.scroll_to_bottom = true;
3383 }
3384
3385 /// Set the offset explicitly. The offset is the distance from the top left of the
3386 /// parent container to the top left of the first child.
3387 /// As you scroll further down the offset becomes more negative.
3388 pub fn set_offset(&self, mut position: Point<Pixels>) {
3389 let state = self.0.borrow();
3390 *state.offset.borrow_mut() = position;
3391 }
3392
3393 /// Get the logical scroll top, based on a child index and a pixel offset.
3394 pub fn logical_scroll_top(&self) -> (usize, Pixels) {
3395 let ix = self.top_item();
3396 let state = self.0.borrow();
3397
3398 if let Some(child_bounds) = state.child_bounds.get(ix) {
3399 (
3400 ix,
3401 child_bounds.top() + state.offset.borrow().y - state.bounds.top(),
3402 )
3403 } else {
3404 (ix, px(0.))
3405 }
3406 }
3407
3408 /// Get the logical scroll bottom, based on a child index and a pixel offset.
3409 pub fn logical_scroll_bottom(&self) -> (usize, Pixels) {
3410 let ix = self.bottom_item();
3411 let state = self.0.borrow();
3412
3413 if let Some(child_bounds) = state.child_bounds.get(ix) {
3414 (
3415 ix,
3416 child_bounds.bottom() + state.offset.borrow().y - state.bounds.bottom(),
3417 )
3418 } else {
3419 (ix, px(0.))
3420 }
3421 }
3422
3423 /// Get the count of children for scrollable item.
3424 pub fn children_count(&self) -> usize {
3425 self.0.borrow().child_bounds.len()
3426 }
3427}
3428
3429#[cfg(test)]
3430mod tests {
3431 use super::*;
3432
3433 #[test]
3434 fn scroll_handle_aligns_wide_children_to_left_edge() {
3435 let handle = ScrollHandle::new();
3436 {
3437 let mut state = handle.0.borrow_mut();
3438 state.bounds = Bounds::new(point(px(0.), px(0.)), size(px(80.), px(20.)));
3439 state.child_bounds = vec![Bounds::new(point(px(25.), px(0.)), size(px(200.), px(20.)))];
3440 state.overflow.x = Overflow::Scroll;
3441 state.active_item = Some(ScrollActiveItem {
3442 index: 0,
3443 strategy: ScrollStrategy::default(),
3444 });
3445 }
3446
3447 handle.scroll_to_active_item();
3448
3449 assert_eq!(handle.offset().x, px(-25.));
3450 }
3451
3452 #[test]
3453 fn scroll_handle_aligns_tall_children_to_top_edge() {
3454 let handle = ScrollHandle::new();
3455 {
3456 let mut state = handle.0.borrow_mut();
3457 state.bounds = Bounds::new(point(px(0.), px(0.)), size(px(20.), px(80.)));
3458 state.child_bounds = vec![Bounds::new(point(px(0.), px(25.)), size(px(20.), px(200.)))];
3459 state.overflow.y = Overflow::Scroll;
3460 state.active_item = Some(ScrollActiveItem {
3461 index: 0,
3462 strategy: ScrollStrategy::default(),
3463 });
3464 }
3465
3466 handle.scroll_to_active_item();
3467
3468 assert_eq!(handle.offset().y, px(-25.));
3469 }
3470}