1use crate::{
2 point, px, Action, AnyDrag, AnyElement, AnyTooltip, AnyView, AppContext, BorrowAppContext,
3 BorrowWindow, Bounds, ClickEvent, DispatchPhase, Element, ElementId, FocusEvent, FocusHandle,
4 IntoElement, KeyContext, KeyDownEvent, KeyUpEvent, LayoutId, MouseButton, MouseDownEvent,
5 MouseMoveEvent, MouseUpEvent, ParentElement, Pixels, Point, Render, ScrollWheelEvent,
6 SharedString, Size, StackingOrder, Style, StyleRefinement, Styled, Task, View, Visibility,
7 WindowContext,
8};
9use collections::HashMap;
10use refineable::Refineable;
11use smallvec::SmallVec;
12use std::{
13 any::{Any, TypeId},
14 cell::RefCell,
15 cmp::Ordering,
16 fmt::Debug,
17 mem,
18 rc::Rc,
19 time::Duration,
20};
21use taffy::style::Overflow;
22use util::ResultExt;
23
24const DRAG_THRESHOLD: f64 = 2.;
25const TOOLTIP_DELAY: Duration = Duration::from_millis(500);
26
27pub struct GroupStyle {
28 pub group: SharedString,
29 pub style: StyleRefinement,
30}
31
32pub trait InteractiveElement: Sized + Element {
33 fn interactivity(&mut self) -> &mut Interactivity;
34
35 fn group(mut self, group: impl Into<SharedString>) -> Self {
36 self.interactivity().group = Some(group.into());
37 self
38 }
39
40 fn id(mut self, id: impl Into<ElementId>) -> Stateful<Self> {
41 self.interactivity().element_id = Some(id.into());
42
43 Stateful { element: self }
44 }
45
46 fn track_focus(mut self, focus_handle: &FocusHandle) -> Focusable<Self> {
47 self.interactivity().focusable = true;
48 self.interactivity().tracked_focus_handle = Some(focus_handle.clone());
49 Focusable { element: self }
50 }
51
52 fn key_context<C, E>(mut self, key_context: C) -> Self
53 where
54 C: TryInto<KeyContext, Error = E>,
55 E: Debug,
56 {
57 if let Some(key_context) = key_context.try_into().log_err() {
58 self.interactivity().key_context = Some(key_context);
59 }
60 self
61 }
62
63 fn hover(mut self, f: impl FnOnce(StyleRefinement) -> StyleRefinement) -> Self {
64 self.interactivity().hover_style = f(StyleRefinement::default());
65 self
66 }
67
68 fn group_hover(
69 mut self,
70 group_name: impl Into<SharedString>,
71 f: impl FnOnce(StyleRefinement) -> StyleRefinement,
72 ) -> Self {
73 self.interactivity().group_hover_style = Some(GroupStyle {
74 group: group_name.into(),
75 style: f(StyleRefinement::default()),
76 });
77 self
78 }
79
80 fn on_mouse_down(
81 mut self,
82 button: MouseButton,
83 listener: impl Fn(&MouseDownEvent, &mut WindowContext) + 'static,
84 ) -> Self {
85 self.interactivity().mouse_down_listeners.push(Box::new(
86 move |event, bounds, phase, cx| {
87 if phase == DispatchPhase::Bubble
88 && event.button == button
89 && bounds.visibly_contains(&event.position, cx)
90 {
91 (listener)(event, cx)
92 }
93 },
94 ));
95 self
96 }
97
98 fn on_any_mouse_down(
99 mut self,
100 listener: impl Fn(&MouseDownEvent, &mut WindowContext) + 'static,
101 ) -> Self {
102 self.interactivity().mouse_down_listeners.push(Box::new(
103 move |event, bounds, phase, cx| {
104 if phase == DispatchPhase::Bubble && bounds.visibly_contains(&event.position, cx) {
105 (listener)(event, cx)
106 }
107 },
108 ));
109 self
110 }
111
112 fn on_mouse_up(
113 mut self,
114 button: MouseButton,
115 listener: impl Fn(&MouseUpEvent, &mut WindowContext) + 'static,
116 ) -> Self {
117 self.interactivity()
118 .mouse_up_listeners
119 .push(Box::new(move |event, bounds, phase, cx| {
120 if phase == DispatchPhase::Bubble
121 && event.button == button
122 && bounds.visibly_contains(&event.position, cx)
123 {
124 (listener)(event, cx)
125 }
126 }));
127 self
128 }
129
130 fn on_any_mouse_up(
131 mut self,
132 listener: impl Fn(&MouseUpEvent, &mut WindowContext) + 'static,
133 ) -> Self {
134 self.interactivity()
135 .mouse_up_listeners
136 .push(Box::new(move |event, bounds, phase, cx| {
137 if phase == DispatchPhase::Bubble && bounds.visibly_contains(&event.position, cx) {
138 (listener)(event, cx)
139 }
140 }));
141 self
142 }
143
144 fn on_mouse_down_out(
145 mut self,
146 listener: impl Fn(&MouseDownEvent, &mut WindowContext) + 'static,
147 ) -> Self {
148 self.interactivity().mouse_down_listeners.push(Box::new(
149 move |event, bounds, phase, cx| {
150 if phase == DispatchPhase::Capture && !bounds.visibly_contains(&event.position, cx)
151 {
152 (listener)(event, cx)
153 }
154 },
155 ));
156 self
157 }
158
159 fn on_mouse_up_out(
160 mut self,
161 button: MouseButton,
162 listener: impl Fn(&MouseUpEvent, &mut WindowContext) + 'static,
163 ) -> Self {
164 self.interactivity()
165 .mouse_up_listeners
166 .push(Box::new(move |event, bounds, phase, cx| {
167 if phase == DispatchPhase::Capture
168 && event.button == button
169 && !bounds.visibly_contains(&event.position, cx)
170 {
171 (listener)(event, cx);
172 }
173 }));
174 self
175 }
176
177 fn on_mouse_move(
178 mut self,
179 listener: impl Fn(&MouseMoveEvent, &mut WindowContext) + 'static,
180 ) -> Self {
181 self.interactivity().mouse_move_listeners.push(Box::new(
182 move |event, bounds, phase, cx| {
183 if phase == DispatchPhase::Bubble && bounds.visibly_contains(&event.position, cx) {
184 (listener)(event, cx);
185 }
186 },
187 ));
188 self
189 }
190
191 fn on_scroll_wheel(
192 mut self,
193 listener: impl Fn(&ScrollWheelEvent, &mut WindowContext) + 'static,
194 ) -> Self {
195 self.interactivity().scroll_wheel_listeners.push(Box::new(
196 move |event, bounds, phase, cx| {
197 if phase == DispatchPhase::Bubble && bounds.visibly_contains(&event.position, cx) {
198 (listener)(event, cx);
199 }
200 },
201 ));
202 self
203 }
204
205 /// Capture the given action, before normal action dispatch can fire
206 fn capture_action<A: Action>(
207 mut self,
208 listener: impl Fn(&A, &mut WindowContext) + 'static,
209 ) -> Self {
210 self.interactivity().action_listeners.push((
211 TypeId::of::<A>(),
212 Box::new(move |action, phase, cx| {
213 let action = action.downcast_ref().unwrap();
214 if phase == DispatchPhase::Capture {
215 (listener)(action, cx)
216 }
217 }),
218 ));
219 self
220 }
221
222 /// Add a listener for the given action, fires during the bubble event phase
223 fn on_action<A: Action>(mut self, listener: impl Fn(&A, &mut WindowContext) + 'static) -> Self {
224 self.interactivity().action_listeners.push((
225 TypeId::of::<A>(),
226 Box::new(move |action, phase, cx| {
227 let action = action.downcast_ref().unwrap();
228 if phase == DispatchPhase::Bubble {
229 (listener)(action, cx)
230 }
231 }),
232 ));
233 self
234 }
235
236 fn on_boxed_action(
237 mut self,
238 action: &Box<dyn Action>,
239 listener: impl Fn(&Box<dyn Action>, &mut WindowContext) + 'static,
240 ) -> Self {
241 let action = action.boxed_clone();
242 self.interactivity().action_listeners.push((
243 (*action).type_id(),
244 Box::new(move |_, phase, cx| {
245 if phase == DispatchPhase::Bubble {
246 (listener)(&action, cx)
247 }
248 }),
249 ));
250 self
251 }
252
253 fn on_key_down(
254 mut self,
255 listener: impl Fn(&KeyDownEvent, &mut WindowContext) + 'static,
256 ) -> Self {
257 self.interactivity()
258 .key_down_listeners
259 .push(Box::new(move |event, phase, cx| {
260 if phase == DispatchPhase::Bubble {
261 (listener)(event, cx)
262 }
263 }));
264 self
265 }
266
267 fn capture_key_down(
268 mut self,
269 listener: impl Fn(&KeyDownEvent, &mut WindowContext) + 'static,
270 ) -> Self {
271 self.interactivity()
272 .key_down_listeners
273 .push(Box::new(move |event, phase, cx| {
274 if phase == DispatchPhase::Capture {
275 listener(event, cx)
276 }
277 }));
278 self
279 }
280
281 fn on_key_up(mut self, listener: impl Fn(&KeyUpEvent, &mut WindowContext) + 'static) -> Self {
282 self.interactivity()
283 .key_up_listeners
284 .push(Box::new(move |event, phase, cx| {
285 if phase == DispatchPhase::Bubble {
286 listener(event, cx)
287 }
288 }));
289 self
290 }
291
292 fn capture_key_up(
293 mut self,
294 listener: impl Fn(&KeyUpEvent, &mut WindowContext) + 'static,
295 ) -> Self {
296 self.interactivity()
297 .key_up_listeners
298 .push(Box::new(move |event, phase, cx| {
299 if phase == DispatchPhase::Capture {
300 listener(event, cx)
301 }
302 }));
303 self
304 }
305
306 fn drag_over<S: 'static>(mut self, f: impl FnOnce(StyleRefinement) -> StyleRefinement) -> Self {
307 self.interactivity()
308 .drag_over_styles
309 .push((TypeId::of::<S>(), f(StyleRefinement::default())));
310 self
311 }
312
313 fn group_drag_over<S: 'static>(
314 mut self,
315 group_name: impl Into<SharedString>,
316 f: impl FnOnce(StyleRefinement) -> StyleRefinement,
317 ) -> Self {
318 self.interactivity().group_drag_over_styles.push((
319 TypeId::of::<S>(),
320 GroupStyle {
321 group: group_name.into(),
322 style: f(StyleRefinement::default()),
323 },
324 ));
325 self
326 }
327
328 fn on_drop<W: 'static>(
329 mut self,
330 listener: impl Fn(&View<W>, &mut WindowContext) + 'static,
331 ) -> Self {
332 self.interactivity().drop_listeners.push((
333 TypeId::of::<W>(),
334 Box::new(move |dragged_view, cx| {
335 listener(&dragged_view.downcast().unwrap(), cx);
336 }),
337 ));
338 self
339 }
340}
341
342pub trait StatefulInteractiveElement: InteractiveElement {
343 fn focusable(mut self) -> Focusable<Self> {
344 self.interactivity().focusable = true;
345 Focusable { element: self }
346 }
347
348 fn overflow_scroll(mut self) -> Self {
349 self.interactivity().base_style.overflow.x = Some(Overflow::Scroll);
350 self.interactivity().base_style.overflow.y = Some(Overflow::Scroll);
351 self
352 }
353
354 fn overflow_x_scroll(mut self) -> Self {
355 self.interactivity().base_style.overflow.x = Some(Overflow::Scroll);
356 self
357 }
358
359 fn overflow_y_scroll(mut self) -> Self {
360 self.interactivity().base_style.overflow.y = Some(Overflow::Scroll);
361 self
362 }
363
364 fn track_scroll(mut self, scroll_handle: &ScrollHandle) -> Self {
365 self.interactivity().scroll_handle = Some(scroll_handle.clone());
366 self
367 }
368
369 fn active(mut self, f: impl FnOnce(StyleRefinement) -> StyleRefinement) -> Self
370 where
371 Self: Sized,
372 {
373 self.interactivity().active_style = f(StyleRefinement::default());
374 self
375 }
376
377 fn group_active(
378 mut self,
379 group_name: impl Into<SharedString>,
380 f: impl FnOnce(StyleRefinement) -> StyleRefinement,
381 ) -> Self
382 where
383 Self: Sized,
384 {
385 self.interactivity().group_active_style = Some(GroupStyle {
386 group: group_name.into(),
387 style: f(StyleRefinement::default()),
388 });
389 self
390 }
391
392 fn on_click(mut self, listener: impl Fn(&ClickEvent, &mut WindowContext) + 'static) -> Self
393 where
394 Self: Sized,
395 {
396 self.interactivity()
397 .click_listeners
398 .push(Box::new(move |event, cx| listener(event, cx)));
399 self
400 }
401
402 fn on_drag<W>(mut self, listener: impl Fn(&mut WindowContext) -> View<W> + 'static) -> Self
403 where
404 Self: Sized,
405 W: 'static + Render,
406 {
407 debug_assert!(
408 self.interactivity().drag_listener.is_none(),
409 "calling on_drag more than once on the same element is not supported"
410 );
411 self.interactivity().drag_listener = Some(Box::new(move |cursor_offset, cx| AnyDrag {
412 view: listener(cx).into(),
413 cursor_offset,
414 }));
415 self
416 }
417
418 fn on_hover(mut self, listener: impl Fn(&bool, &mut WindowContext) + 'static) -> Self
419 where
420 Self: Sized,
421 {
422 debug_assert!(
423 self.interactivity().hover_listener.is_none(),
424 "calling on_hover more than once on the same element is not supported"
425 );
426 self.interactivity().hover_listener = Some(Box::new(listener));
427 self
428 }
429
430 fn tooltip(mut self, build_tooltip: impl Fn(&mut WindowContext) -> AnyView + 'static) -> Self
431 where
432 Self: Sized,
433 {
434 debug_assert!(
435 self.interactivity().tooltip_builder.is_none(),
436 "calling tooltip more than once on the same element is not supported"
437 );
438 self.interactivity().tooltip_builder = Some(Rc::new(build_tooltip));
439
440 self
441 }
442}
443
444pub trait FocusableElement: InteractiveElement {
445 fn focus(mut self, f: impl FnOnce(StyleRefinement) -> StyleRefinement) -> Self
446 where
447 Self: Sized,
448 {
449 self.interactivity().focus_style = f(StyleRefinement::default());
450 self
451 }
452
453 fn in_focus(mut self, f: impl FnOnce(StyleRefinement) -> StyleRefinement) -> Self
454 where
455 Self: Sized,
456 {
457 self.interactivity().in_focus_style = f(StyleRefinement::default());
458 self
459 }
460
461 fn on_focus(mut self, listener: impl Fn(&FocusEvent, &mut WindowContext) + 'static) -> Self
462 where
463 Self: Sized,
464 {
465 self.interactivity()
466 .focus_listeners
467 .push(Box::new(move |focus_handle, event, cx| {
468 if event.focused.as_ref() == Some(focus_handle) {
469 listener(event, cx)
470 }
471 }));
472 self
473 }
474
475 fn on_blur(mut self, listener: impl Fn(&FocusEvent, &mut WindowContext) + 'static) -> Self
476 where
477 Self: Sized,
478 {
479 self.interactivity()
480 .focus_listeners
481 .push(Box::new(move |focus_handle, event, cx| {
482 if event.blurred.as_ref() == Some(focus_handle) {
483 listener(event, cx)
484 }
485 }));
486 self
487 }
488
489 fn on_focus_in(mut self, listener: impl Fn(&FocusEvent, &mut WindowContext) + 'static) -> Self
490 where
491 Self: Sized,
492 {
493 self.interactivity()
494 .focus_listeners
495 .push(Box::new(move |focus_handle, event, cx| {
496 let descendant_blurred = event
497 .blurred
498 .as_ref()
499 .map_or(false, |blurred| focus_handle.contains(blurred, cx));
500 let descendant_focused = event
501 .focused
502 .as_ref()
503 .map_or(false, |focused| focus_handle.contains(focused, cx));
504
505 if !descendant_blurred && descendant_focused {
506 listener(event, cx)
507 }
508 }));
509 self
510 }
511
512 fn on_focus_out(mut self, listener: impl Fn(&FocusEvent, &mut WindowContext) + 'static) -> Self
513 where
514 Self: Sized,
515 {
516 self.interactivity()
517 .focus_listeners
518 .push(Box::new(move |focus_handle, event, cx| {
519 let descendant_blurred = event
520 .blurred
521 .as_ref()
522 .map_or(false, |blurred| focus_handle.contains(blurred, cx));
523 let descendant_focused = event
524 .focused
525 .as_ref()
526 .map_or(false, |focused| focus_handle.contains(focused, cx));
527 if descendant_blurred && !descendant_focused {
528 listener(event, cx)
529 }
530 }));
531 self
532 }
533}
534
535pub type FocusListeners = SmallVec<[FocusListener; 2]>;
536
537pub type FocusListener = Box<dyn Fn(&FocusHandle, &FocusEvent, &mut WindowContext) + 'static>;
538
539pub type MouseDownListener =
540 Box<dyn Fn(&MouseDownEvent, &InteractiveBounds, DispatchPhase, &mut WindowContext) + 'static>;
541pub type MouseUpListener =
542 Box<dyn Fn(&MouseUpEvent, &InteractiveBounds, DispatchPhase, &mut WindowContext) + 'static>;
543
544pub type MouseMoveListener =
545 Box<dyn Fn(&MouseMoveEvent, &InteractiveBounds, DispatchPhase, &mut WindowContext) + 'static>;
546
547pub type ScrollWheelListener =
548 Box<dyn Fn(&ScrollWheelEvent, &InteractiveBounds, DispatchPhase, &mut WindowContext) + 'static>;
549
550pub type ClickListener = Box<dyn Fn(&ClickEvent, &mut WindowContext) + 'static>;
551
552pub type DragListener = Box<dyn Fn(Point<Pixels>, &mut WindowContext) -> AnyDrag + 'static>;
553
554type DropListener = dyn Fn(AnyView, &mut WindowContext) + 'static;
555
556pub type TooltipBuilder = Rc<dyn Fn(&mut WindowContext) -> AnyView + 'static>;
557
558pub type KeyDownListener = Box<dyn Fn(&KeyDownEvent, DispatchPhase, &mut WindowContext) + 'static>;
559
560pub type KeyUpListener = Box<dyn Fn(&KeyUpEvent, DispatchPhase, &mut WindowContext) + 'static>;
561
562pub type ActionListener = Box<dyn Fn(&dyn Any, DispatchPhase, &mut WindowContext) + 'static>;
563
564pub fn div() -> Div {
565 Div {
566 interactivity: Interactivity::default(),
567 children: SmallVec::default(),
568 }
569}
570
571pub struct Div {
572 interactivity: Interactivity,
573 children: SmallVec<[AnyElement; 2]>,
574}
575
576impl Styled for Div {
577 fn style(&mut self) -> &mut StyleRefinement {
578 &mut self.interactivity.base_style
579 }
580}
581
582impl InteractiveElement for Div {
583 fn interactivity(&mut self) -> &mut Interactivity {
584 &mut self.interactivity
585 }
586}
587
588impl ParentElement for Div {
589 fn children_mut(&mut self) -> &mut SmallVec<[AnyElement; 2]> {
590 &mut self.children
591 }
592}
593
594impl Element for Div {
595 type State = DivState;
596
597 fn layout(
598 &mut self,
599 element_state: Option<Self::State>,
600 cx: &mut WindowContext,
601 ) -> (LayoutId, Self::State) {
602 let mut child_layout_ids = SmallVec::new();
603 let mut interactivity = mem::take(&mut self.interactivity);
604 let (layout_id, interactive_state) = interactivity.layout(
605 element_state.map(|s| s.interactive_state),
606 cx,
607 |style, cx| {
608 cx.with_text_style(style.text_style().cloned(), |cx| {
609 child_layout_ids = self
610 .children
611 .iter_mut()
612 .map(|child| child.layout(cx))
613 .collect::<SmallVec<_>>();
614 cx.request_layout(&style, child_layout_ids.iter().copied())
615 })
616 },
617 );
618 self.interactivity = interactivity;
619 (
620 layout_id,
621 DivState {
622 interactive_state,
623 child_layout_ids,
624 },
625 )
626 }
627
628 fn paint(
629 self,
630 bounds: Bounds<Pixels>,
631 element_state: &mut Self::State,
632 cx: &mut WindowContext,
633 ) {
634 let mut child_min = point(Pixels::MAX, Pixels::MAX);
635 let mut child_max = Point::default();
636 let content_size = if element_state.child_layout_ids.is_empty() {
637 bounds.size
638 } else if let Some(scroll_handle) = self.interactivity.scroll_handle.as_ref() {
639 let mut state = scroll_handle.0.borrow_mut();
640 state.child_bounds = Vec::with_capacity(element_state.child_layout_ids.len());
641 state.bounds = bounds;
642 let requested = state.requested_scroll_top.take();
643
644 for (ix, child_layout_id) in element_state.child_layout_ids.iter().enumerate() {
645 let child_bounds = cx.layout_bounds(*child_layout_id);
646 child_min = child_min.min(&child_bounds.origin);
647 child_max = child_max.max(&child_bounds.lower_right());
648 state.child_bounds.push(child_bounds);
649
650 if let Some(requested) = requested.as_ref() {
651 if requested.0 == ix {
652 *state.offset.borrow_mut() =
653 bounds.origin - (child_bounds.origin - point(px(0.), requested.1));
654 }
655 }
656 }
657 (child_max - child_min).into()
658 } else {
659 for child_layout_id in &element_state.child_layout_ids {
660 let child_bounds = cx.layout_bounds(*child_layout_id);
661 child_min = child_min.min(&child_bounds.origin);
662 child_max = child_max.max(&child_bounds.lower_right());
663 }
664 (child_max - child_min).into()
665 };
666
667 self.interactivity.paint(
668 bounds,
669 content_size,
670 &mut element_state.interactive_state,
671 cx,
672 |style, scroll_offset, cx| {
673 if style.visibility == Visibility::Hidden {
674 return;
675 }
676
677 let z_index = style.z_index.unwrap_or(0);
678
679 cx.with_z_index(z_index, |cx| {
680 cx.with_z_index(0, |cx| {
681 style.paint(bounds, cx);
682 });
683 cx.with_z_index(1, |cx| {
684 cx.with_text_style(style.text_style().cloned(), |cx| {
685 cx.with_content_mask(style.overflow_mask(bounds), |cx| {
686 cx.with_element_offset(scroll_offset, |cx| {
687 for child in self.children {
688 child.paint(cx);
689 }
690 })
691 })
692 })
693 })
694 })
695 },
696 );
697 }
698}
699
700impl IntoElement for Div {
701 type Element = Self;
702
703 fn element_id(&self) -> Option<ElementId> {
704 self.interactivity.element_id.clone()
705 }
706
707 fn into_element(self) -> Self::Element {
708 self
709 }
710}
711
712pub struct DivState {
713 child_layout_ids: SmallVec<[LayoutId; 4]>,
714 interactive_state: InteractiveElementState,
715}
716
717impl DivState {
718 pub fn is_active(&self) -> bool {
719 self.interactive_state.pending_mouse_down.borrow().is_some()
720 }
721}
722
723pub struct Interactivity {
724 pub element_id: Option<ElementId>,
725 pub key_context: Option<KeyContext>,
726 pub focusable: bool,
727 pub tracked_focus_handle: Option<FocusHandle>,
728 pub scroll_handle: Option<ScrollHandle>,
729 pub focus_listeners: FocusListeners,
730 pub group: Option<SharedString>,
731 pub base_style: StyleRefinement,
732 pub focus_style: StyleRefinement,
733 pub in_focus_style: StyleRefinement,
734 pub hover_style: StyleRefinement,
735 pub group_hover_style: Option<GroupStyle>,
736 pub active_style: StyleRefinement,
737 pub group_active_style: Option<GroupStyle>,
738 pub drag_over_styles: SmallVec<[(TypeId, StyleRefinement); 2]>,
739 pub group_drag_over_styles: SmallVec<[(TypeId, GroupStyle); 2]>,
740 pub mouse_down_listeners: SmallVec<[MouseDownListener; 2]>,
741 pub mouse_up_listeners: SmallVec<[MouseUpListener; 2]>,
742 pub mouse_move_listeners: SmallVec<[MouseMoveListener; 2]>,
743 pub scroll_wheel_listeners: SmallVec<[ScrollWheelListener; 2]>,
744 pub key_down_listeners: SmallVec<[KeyDownListener; 2]>,
745 pub key_up_listeners: SmallVec<[KeyUpListener; 2]>,
746 pub action_listeners: SmallVec<[(TypeId, ActionListener); 8]>,
747 pub drop_listeners: SmallVec<[(TypeId, Box<DropListener>); 2]>,
748 pub click_listeners: SmallVec<[ClickListener; 2]>,
749 pub drag_listener: Option<DragListener>,
750 pub hover_listener: Option<Box<dyn Fn(&bool, &mut WindowContext)>>,
751 pub tooltip_builder: Option<TooltipBuilder>,
752}
753
754#[derive(Clone)]
755pub struct InteractiveBounds {
756 pub bounds: Bounds<Pixels>,
757 pub stacking_order: StackingOrder,
758}
759
760impl InteractiveBounds {
761 pub fn visibly_contains(&self, point: &Point<Pixels>, cx: &WindowContext) -> bool {
762 self.bounds.contains_point(point) && cx.was_top_layer(&point, &self.stacking_order)
763 }
764}
765
766impl Interactivity {
767 pub fn layout(
768 &mut self,
769 element_state: Option<InteractiveElementState>,
770 cx: &mut WindowContext,
771 f: impl FnOnce(Style, &mut WindowContext) -> LayoutId,
772 ) -> (LayoutId, InteractiveElementState) {
773 let mut element_state = element_state.unwrap_or_default();
774
775 // Ensure we store a focus handle in our element state if we're focusable.
776 // If there's an explicit focus handle we're tracking, use that. Otherwise
777 // create a new handle and store it in the element state, which lives for as
778 // as frames contain an element with this id.
779 if self.focusable {
780 element_state.focus_handle.get_or_insert_with(|| {
781 self.tracked_focus_handle
782 .clone()
783 .unwrap_or_else(|| cx.focus_handle())
784 });
785 }
786
787 if let Some(scroll_handle) = self.scroll_handle.as_ref() {
788 element_state.scroll_offset = Some(scroll_handle.0.borrow().offset.clone());
789 }
790
791 let style = self.compute_style(None, &mut element_state, cx);
792 let layout_id = f(style, cx);
793 (layout_id, element_state)
794 }
795
796 pub fn paint(
797 mut self,
798 bounds: Bounds<Pixels>,
799 content_size: Size<Pixels>,
800 element_state: &mut InteractiveElementState,
801 cx: &mut WindowContext,
802 f: impl FnOnce(Style, Point<Pixels>, &mut WindowContext),
803 ) {
804 let style = self.compute_style(Some(bounds), element_state, cx);
805
806 if style
807 .background
808 .as_ref()
809 .is_some_and(|fill| fill.color().is_some_and(|color| !color.is_transparent()))
810 {
811 cx.with_z_index(style.z_index.unwrap_or(0), |cx| cx.add_opaque_layer(bounds))
812 }
813
814 let interactive_bounds = Rc::new(InteractiveBounds {
815 bounds: bounds.intersect(&cx.content_mask().bounds),
816 stacking_order: cx.stacking_order().clone(),
817 });
818
819 if let Some(mouse_cursor) = style.mouse_cursor {
820 let mouse_position = &cx.mouse_position();
821 let hovered = interactive_bounds.visibly_contains(mouse_position, cx);
822 if hovered {
823 cx.set_cursor_style(mouse_cursor);
824 }
825 }
826
827 for listener in self.mouse_down_listeners.drain(..) {
828 let interactive_bounds = interactive_bounds.clone();
829 cx.on_mouse_event(move |event: &MouseDownEvent, phase, cx| {
830 listener(event, &*interactive_bounds, phase, cx);
831 })
832 }
833
834 for listener in self.mouse_up_listeners.drain(..) {
835 let interactive_bounds = interactive_bounds.clone();
836 cx.on_mouse_event(move |event: &MouseUpEvent, phase, cx| {
837 listener(event, &*interactive_bounds, phase, cx);
838 })
839 }
840
841 for listener in self.mouse_move_listeners.drain(..) {
842 let interactive_bounds = interactive_bounds.clone();
843 cx.on_mouse_event(move |event: &MouseMoveEvent, phase, cx| {
844 listener(event, &*interactive_bounds, phase, cx);
845 })
846 }
847
848 for listener in self.scroll_wheel_listeners.drain(..) {
849 let interactive_bounds = interactive_bounds.clone();
850 cx.on_mouse_event(move |event: &ScrollWheelEvent, phase, cx| {
851 listener(event, &*interactive_bounds, phase, cx);
852 })
853 }
854
855 let hover_group_bounds = self
856 .group_hover_style
857 .as_ref()
858 .and_then(|group_hover| GroupBounds::get(&group_hover.group, cx));
859
860 if let Some(group_bounds) = hover_group_bounds {
861 let hovered = group_bounds.contains_point(&cx.mouse_position());
862 cx.on_mouse_event(move |event: &MouseMoveEvent, phase, cx| {
863 if phase == DispatchPhase::Capture {
864 if group_bounds.contains_point(&event.position) != hovered {
865 cx.notify();
866 }
867 }
868 });
869 }
870
871 if self.hover_style.is_some()
872 || self.base_style.mouse_cursor.is_some()
873 || cx.active_drag.is_some() && !self.drag_over_styles.is_empty()
874 {
875 let bounds = bounds.intersect(&cx.content_mask().bounds);
876 let hovered = bounds.contains_point(&cx.mouse_position());
877 cx.on_mouse_event(move |event: &MouseMoveEvent, phase, cx| {
878 if phase == DispatchPhase::Capture {
879 if bounds.contains_point(&event.position) != hovered {
880 cx.notify();
881 }
882 }
883 });
884 }
885
886 if cx.active_drag.is_some() {
887 let drop_listeners = mem::take(&mut self.drop_listeners);
888 let interactive_bounds = interactive_bounds.clone();
889 cx.on_mouse_event(move |event: &MouseUpEvent, phase, cx| {
890 if phase == DispatchPhase::Bubble
891 && interactive_bounds.visibly_contains(&event.position, &cx)
892 {
893 if let Some(drag_state_type) =
894 cx.active_drag.as_ref().map(|drag| drag.view.entity_type())
895 {
896 for (drop_state_type, listener) in &drop_listeners {
897 if *drop_state_type == drag_state_type {
898 let drag = cx
899 .active_drag
900 .take()
901 .expect("checked for type drag state type above");
902 listener(drag.view.clone(), cx);
903 cx.notify();
904 cx.stop_propagation();
905 }
906 }
907 }
908 }
909 });
910 }
911
912 let click_listeners = mem::take(&mut self.click_listeners);
913 let drag_listener = mem::take(&mut self.drag_listener);
914
915 if !click_listeners.is_empty() || drag_listener.is_some() {
916 let pending_mouse_down = element_state.pending_mouse_down.clone();
917 let mouse_down = pending_mouse_down.borrow().clone();
918 if let Some(mouse_down) = mouse_down {
919 if let Some(drag_listener) = drag_listener {
920 let active_state = element_state.clicked_state.clone();
921 let interactive_bounds = interactive_bounds.clone();
922
923 cx.on_mouse_event(move |event: &MouseMoveEvent, phase, cx| {
924 if cx.active_drag.is_some() {
925 if phase == DispatchPhase::Capture {
926 cx.notify();
927 }
928 } else if phase == DispatchPhase::Bubble
929 && interactive_bounds.visibly_contains(&event.position, cx)
930 && (event.position - mouse_down.position).magnitude() > DRAG_THRESHOLD
931 {
932 *active_state.borrow_mut() = ElementClickedState::default();
933 let cursor_offset = event.position - bounds.origin;
934 let drag = drag_listener(cursor_offset, cx);
935 cx.active_drag = Some(drag);
936 cx.notify();
937 cx.stop_propagation();
938 }
939 });
940 }
941
942 let interactive_bounds = interactive_bounds.clone();
943 cx.on_mouse_event(move |event: &MouseUpEvent, phase, cx| {
944 if phase == DispatchPhase::Bubble
945 && interactive_bounds.visibly_contains(&event.position, cx)
946 {
947 let mouse_click = ClickEvent {
948 down: mouse_down.clone(),
949 up: event.clone(),
950 };
951 for listener in &click_listeners {
952 listener(&mouse_click, cx);
953 }
954 }
955 *pending_mouse_down.borrow_mut() = None;
956 cx.notify();
957 });
958 } else {
959 let interactive_bounds = interactive_bounds.clone();
960 cx.on_mouse_event(move |event: &MouseDownEvent, phase, cx| {
961 if phase == DispatchPhase::Bubble
962 && interactive_bounds.visibly_contains(&event.position, cx)
963 {
964 *pending_mouse_down.borrow_mut() = Some(event.clone());
965 cx.notify();
966 }
967 });
968 }
969 }
970
971 if let Some(hover_listener) = self.hover_listener.take() {
972 let was_hovered = element_state.hover_state.clone();
973 let has_mouse_down = element_state.pending_mouse_down.clone();
974 let interactive_bounds = interactive_bounds.clone();
975
976 cx.on_mouse_event(move |event: &MouseMoveEvent, phase, cx| {
977 if phase != DispatchPhase::Bubble {
978 return;
979 }
980 let is_hovered = interactive_bounds.visibly_contains(&event.position, cx)
981 && has_mouse_down.borrow().is_none();
982 let mut was_hovered = was_hovered.borrow_mut();
983
984 if is_hovered != was_hovered.clone() {
985 *was_hovered = is_hovered;
986 drop(was_hovered);
987
988 hover_listener(&is_hovered, cx);
989 }
990 });
991 }
992
993 if let Some(tooltip_builder) = self.tooltip_builder.take() {
994 let active_tooltip = element_state.active_tooltip.clone();
995 let pending_mouse_down = element_state.pending_mouse_down.clone();
996 let interactive_bounds = interactive_bounds.clone();
997
998 cx.on_mouse_event(move |event: &MouseMoveEvent, phase, cx| {
999 let is_hovered = interactive_bounds.visibly_contains(&event.position, cx)
1000 && pending_mouse_down.borrow().is_none();
1001 if !is_hovered {
1002 active_tooltip.borrow_mut().take();
1003 return;
1004 }
1005
1006 if phase != DispatchPhase::Bubble {
1007 return;
1008 }
1009
1010 if active_tooltip.borrow().is_none() {
1011 let task = cx.spawn({
1012 let active_tooltip = active_tooltip.clone();
1013 let tooltip_builder = tooltip_builder.clone();
1014
1015 move |mut cx| async move {
1016 cx.background_executor().timer(TOOLTIP_DELAY).await;
1017 cx.update(|_, cx| {
1018 active_tooltip.borrow_mut().replace(ActiveTooltip {
1019 tooltip: Some(AnyTooltip {
1020 view: tooltip_builder(cx),
1021 cursor_offset: cx.mouse_position(),
1022 }),
1023 _task: None,
1024 });
1025 cx.notify();
1026 })
1027 .ok();
1028 }
1029 });
1030 active_tooltip.borrow_mut().replace(ActiveTooltip {
1031 tooltip: None,
1032 _task: Some(task),
1033 });
1034 }
1035 });
1036
1037 let active_tooltip = element_state.active_tooltip.clone();
1038 cx.on_mouse_event(move |_: &MouseDownEvent, _, _| {
1039 active_tooltip.borrow_mut().take();
1040 });
1041
1042 if let Some(active_tooltip) = element_state.active_tooltip.borrow().as_ref() {
1043 if active_tooltip.tooltip.is_some() {
1044 cx.active_tooltip = active_tooltip.tooltip.clone()
1045 }
1046 }
1047 }
1048
1049 let active_state = element_state.clicked_state.clone();
1050 if !active_state.borrow().is_clicked() {
1051 cx.on_mouse_event(move |_: &MouseUpEvent, phase, cx| {
1052 if phase == DispatchPhase::Capture {
1053 *active_state.borrow_mut() = ElementClickedState::default();
1054 cx.notify();
1055 }
1056 });
1057 } else {
1058 let active_group_bounds = self
1059 .group_active_style
1060 .as_ref()
1061 .and_then(|group_active| GroupBounds::get(&group_active.group, cx));
1062 let interactive_bounds = interactive_bounds.clone();
1063 cx.on_mouse_event(move |down: &MouseDownEvent, phase, cx| {
1064 if phase == DispatchPhase::Bubble {
1065 let group = active_group_bounds
1066 .map_or(false, |bounds| bounds.contains_point(&down.position));
1067 let element = interactive_bounds.visibly_contains(&down.position, cx);
1068 if group || element {
1069 *active_state.borrow_mut() = ElementClickedState { group, element };
1070 cx.notify();
1071 }
1072 }
1073 });
1074 }
1075
1076 let overflow = style.overflow;
1077 if overflow.x == Overflow::Scroll || overflow.y == Overflow::Scroll {
1078 let scroll_offset = element_state
1079 .scroll_offset
1080 .get_or_insert_with(Rc::default)
1081 .clone();
1082 let line_height = cx.line_height();
1083 let scroll_max = (content_size - bounds.size).max(&Size::default());
1084 let interactive_bounds = interactive_bounds.clone();
1085
1086 cx.on_mouse_event(move |event: &ScrollWheelEvent, phase, cx| {
1087 if phase == DispatchPhase::Bubble
1088 && interactive_bounds.visibly_contains(&event.position, cx)
1089 {
1090 let mut scroll_offset = scroll_offset.borrow_mut();
1091 let old_scroll_offset = *scroll_offset;
1092 let delta = event.delta.pixel_delta(line_height);
1093
1094 if overflow.x == Overflow::Scroll {
1095 scroll_offset.x =
1096 (scroll_offset.x + delta.x).clamp(-scroll_max.width, px(0.));
1097 }
1098
1099 if overflow.y == Overflow::Scroll {
1100 scroll_offset.y =
1101 (scroll_offset.y + delta.y).clamp(-scroll_max.height, px(0.));
1102 }
1103
1104 if *scroll_offset != old_scroll_offset {
1105 cx.notify();
1106 cx.stop_propagation();
1107 }
1108 }
1109 });
1110 }
1111
1112 if let Some(group) = self.group.clone() {
1113 GroupBounds::push(group, bounds, cx);
1114 }
1115
1116 let scroll_offset = element_state
1117 .scroll_offset
1118 .as_ref()
1119 .map(|scroll_offset| *scroll_offset.borrow());
1120
1121 cx.with_key_dispatch(
1122 self.key_context.clone(),
1123 element_state.focus_handle.clone(),
1124 |_, cx| {
1125 for listener in self.key_down_listeners.drain(..) {
1126 cx.on_key_event(move |event: &KeyDownEvent, phase, cx| {
1127 listener(event, phase, cx);
1128 })
1129 }
1130
1131 for listener in self.key_up_listeners.drain(..) {
1132 cx.on_key_event(move |event: &KeyUpEvent, phase, cx| {
1133 listener(event, phase, cx);
1134 })
1135 }
1136
1137 for (action_type, listener) in self.action_listeners {
1138 cx.on_action(action_type, listener)
1139 }
1140
1141 if let Some(focus_handle) = element_state.focus_handle.as_ref() {
1142 for listener in self.focus_listeners {
1143 let focus_handle = focus_handle.clone();
1144 cx.on_focus_changed(move |event, cx| listener(&focus_handle, event, cx));
1145 }
1146 }
1147
1148 f(style, scroll_offset.unwrap_or_default(), cx)
1149 },
1150 );
1151
1152 if let Some(group) = self.group.as_ref() {
1153 GroupBounds::pop(group, cx);
1154 }
1155 }
1156
1157 pub fn compute_style(
1158 &self,
1159 bounds: Option<Bounds<Pixels>>,
1160 element_state: &mut InteractiveElementState,
1161 cx: &mut WindowContext,
1162 ) -> Style {
1163 let mut style = Style::default();
1164 style.refine(&self.base_style);
1165
1166 if let Some(focus_handle) = self.tracked_focus_handle.as_ref() {
1167 if focus_handle.within_focused(cx) {
1168 style.refine(&self.in_focus_style);
1169 }
1170
1171 if focus_handle.is_focused(cx) {
1172 style.refine(&self.focus_style);
1173 }
1174 }
1175
1176 if let Some(bounds) = bounds {
1177 let mouse_position = cx.mouse_position();
1178 if let Some(group_hover) = self.group_hover_style.as_ref() {
1179 if let Some(group_bounds) = GroupBounds::get(&group_hover.group, cx) {
1180 if group_bounds.contains_point(&mouse_position)
1181 && cx.was_top_layer(&mouse_position, cx.stacking_order())
1182 {
1183 style.refine(&group_hover.style);
1184 }
1185 }
1186 }
1187 if self.hover_style.is_some() {
1188 if bounds
1189 .intersect(&cx.content_mask().bounds)
1190 .contains_point(&mouse_position)
1191 && cx.was_top_layer(&mouse_position, cx.stacking_order())
1192 {
1193 style.refine(&self.hover_style);
1194 }
1195 }
1196
1197 if let Some(drag) = cx.active_drag.take() {
1198 for (state_type, group_drag_style) in &self.group_drag_over_styles {
1199 if let Some(group_bounds) = GroupBounds::get(&group_drag_style.group, cx) {
1200 if *state_type == drag.view.entity_type()
1201 && group_bounds.contains_point(&mouse_position)
1202 {
1203 style.refine(&group_drag_style.style);
1204 }
1205 }
1206 }
1207
1208 for (state_type, drag_over_style) in &self.drag_over_styles {
1209 if *state_type == drag.view.entity_type()
1210 && bounds
1211 .intersect(&cx.content_mask().bounds)
1212 .contains_point(&mouse_position)
1213 {
1214 style.refine(drag_over_style);
1215 }
1216 }
1217
1218 cx.active_drag = Some(drag);
1219 }
1220 }
1221
1222 let clicked_state = element_state.clicked_state.borrow();
1223 if clicked_state.group {
1224 if let Some(group) = self.group_active_style.as_ref() {
1225 style.refine(&group.style)
1226 }
1227 }
1228
1229 if clicked_state.element {
1230 style.refine(&self.active_style)
1231 }
1232
1233 style
1234 }
1235}
1236
1237impl Default for Interactivity {
1238 fn default() -> Self {
1239 Self {
1240 element_id: None,
1241 key_context: None,
1242 focusable: false,
1243 tracked_focus_handle: None,
1244 scroll_handle: None,
1245 focus_listeners: SmallVec::default(),
1246 // scroll_offset: Point::default(),
1247 group: None,
1248 base_style: StyleRefinement::default(),
1249 focus_style: StyleRefinement::default(),
1250 in_focus_style: StyleRefinement::default(),
1251 hover_style: StyleRefinement::default(),
1252 group_hover_style: None,
1253 active_style: StyleRefinement::default(),
1254 group_active_style: None,
1255 drag_over_styles: SmallVec::new(),
1256 group_drag_over_styles: SmallVec::new(),
1257 mouse_down_listeners: SmallVec::new(),
1258 mouse_up_listeners: SmallVec::new(),
1259 mouse_move_listeners: SmallVec::new(),
1260 scroll_wheel_listeners: SmallVec::new(),
1261 key_down_listeners: SmallVec::new(),
1262 key_up_listeners: SmallVec::new(),
1263 action_listeners: SmallVec::new(),
1264 drop_listeners: SmallVec::new(),
1265 click_listeners: SmallVec::new(),
1266 drag_listener: None,
1267 hover_listener: None,
1268 tooltip_builder: None,
1269 }
1270 }
1271}
1272
1273#[derive(Default)]
1274pub struct InteractiveElementState {
1275 pub focus_handle: Option<FocusHandle>,
1276 pub clicked_state: Rc<RefCell<ElementClickedState>>,
1277 pub hover_state: Rc<RefCell<bool>>,
1278 pub pending_mouse_down: Rc<RefCell<Option<MouseDownEvent>>>,
1279 pub scroll_offset: Option<Rc<RefCell<Point<Pixels>>>>,
1280 pub active_tooltip: Rc<RefCell<Option<ActiveTooltip>>>,
1281}
1282
1283pub struct ActiveTooltip {
1284 tooltip: Option<AnyTooltip>,
1285 _task: Option<Task<()>>,
1286}
1287
1288/// Whether or not the element or a group that contains it is clicked by the mouse.
1289#[derive(Copy, Clone, Default, Eq, PartialEq)]
1290pub struct ElementClickedState {
1291 pub group: bool,
1292 pub element: bool,
1293}
1294
1295impl ElementClickedState {
1296 fn is_clicked(&self) -> bool {
1297 self.group || self.element
1298 }
1299}
1300
1301#[derive(Default)]
1302pub struct GroupBounds(HashMap<SharedString, SmallVec<[Bounds<Pixels>; 1]>>);
1303
1304impl GroupBounds {
1305 pub fn get(name: &SharedString, cx: &mut AppContext) -> Option<Bounds<Pixels>> {
1306 cx.default_global::<Self>()
1307 .0
1308 .get(name)
1309 .and_then(|bounds_stack| bounds_stack.last())
1310 .cloned()
1311 }
1312
1313 pub fn push(name: SharedString, bounds: Bounds<Pixels>, cx: &mut AppContext) {
1314 cx.default_global::<Self>()
1315 .0
1316 .entry(name)
1317 .or_default()
1318 .push(bounds);
1319 }
1320
1321 pub fn pop(name: &SharedString, cx: &mut AppContext) {
1322 cx.default_global::<Self>().0.get_mut(name).unwrap().pop();
1323 }
1324}
1325
1326pub struct Focusable<E> {
1327 element: E,
1328}
1329
1330impl<E: InteractiveElement> FocusableElement for Focusable<E> {}
1331
1332impl<E> InteractiveElement for Focusable<E>
1333where
1334 E: InteractiveElement,
1335{
1336 fn interactivity(&mut self) -> &mut Interactivity {
1337 self.element.interactivity()
1338 }
1339}
1340
1341impl<E: StatefulInteractiveElement> StatefulInteractiveElement for Focusable<E> {}
1342
1343impl<E> Styled for Focusable<E>
1344where
1345 E: Styled,
1346{
1347 fn style(&mut self) -> &mut StyleRefinement {
1348 self.element.style()
1349 }
1350}
1351
1352impl<E> Element for Focusable<E>
1353where
1354 E: Element,
1355{
1356 type State = E::State;
1357
1358 fn layout(
1359 &mut self,
1360 state: Option<Self::State>,
1361 cx: &mut WindowContext,
1362 ) -> (LayoutId, Self::State) {
1363 self.element.layout(state, cx)
1364 }
1365
1366 fn paint(self, bounds: Bounds<Pixels>, state: &mut Self::State, cx: &mut WindowContext) {
1367 self.element.paint(bounds, state, cx)
1368 }
1369}
1370
1371impl<E> IntoElement for Focusable<E>
1372where
1373 E: Element,
1374{
1375 type Element = E;
1376
1377 fn element_id(&self) -> Option<ElementId> {
1378 self.element.element_id()
1379 }
1380
1381 fn into_element(self) -> Self::Element {
1382 self.element
1383 }
1384}
1385
1386impl<E> ParentElement for Focusable<E>
1387where
1388 E: ParentElement,
1389{
1390 fn children_mut(&mut self) -> &mut SmallVec<[AnyElement; 2]> {
1391 self.element.children_mut()
1392 }
1393}
1394
1395pub struct Stateful<E> {
1396 element: E,
1397}
1398
1399impl<E> Styled for Stateful<E>
1400where
1401 E: Styled,
1402{
1403 fn style(&mut self) -> &mut StyleRefinement {
1404 self.element.style()
1405 }
1406}
1407
1408impl<E> StatefulInteractiveElement for Stateful<E>
1409where
1410 E: Element,
1411 Self: InteractiveElement,
1412{
1413}
1414
1415impl<E> InteractiveElement for Stateful<E>
1416where
1417 E: InteractiveElement,
1418{
1419 fn interactivity(&mut self) -> &mut Interactivity {
1420 self.element.interactivity()
1421 }
1422}
1423
1424impl<E: FocusableElement> FocusableElement for Stateful<E> {}
1425
1426impl<E> Element for Stateful<E>
1427where
1428 E: Element,
1429{
1430 type State = E::State;
1431
1432 fn layout(
1433 &mut self,
1434 state: Option<Self::State>,
1435 cx: &mut WindowContext,
1436 ) -> (LayoutId, Self::State) {
1437 self.element.layout(state, cx)
1438 }
1439
1440 fn paint(self, bounds: Bounds<Pixels>, state: &mut Self::State, cx: &mut WindowContext) {
1441 self.element.paint(bounds, state, cx)
1442 }
1443}
1444
1445impl<E> IntoElement for Stateful<E>
1446where
1447 E: Element,
1448{
1449 type Element = Self;
1450
1451 fn element_id(&self) -> Option<ElementId> {
1452 self.element.element_id()
1453 }
1454
1455 fn into_element(self) -> Self::Element {
1456 self
1457 }
1458}
1459
1460impl<E> ParentElement for Stateful<E>
1461where
1462 E: ParentElement,
1463{
1464 fn children_mut(&mut self) -> &mut SmallVec<[AnyElement; 2]> {
1465 self.element.children_mut()
1466 }
1467}
1468
1469#[derive(Default)]
1470struct ScrollHandleState {
1471 // not great to have the nested rc's...
1472 offset: Rc<RefCell<Point<Pixels>>>,
1473 bounds: Bounds<Pixels>,
1474 child_bounds: Vec<Bounds<Pixels>>,
1475 requested_scroll_top: Option<(usize, Pixels)>,
1476}
1477
1478#[derive(Clone)]
1479pub struct ScrollHandle(Rc<RefCell<ScrollHandleState>>);
1480
1481impl ScrollHandle {
1482 pub fn new() -> Self {
1483 Self(Rc::default())
1484 }
1485
1486 pub fn offset(&self) -> Point<Pixels> {
1487 self.0.borrow().offset.borrow().clone()
1488 }
1489
1490 pub fn top_item(&self) -> usize {
1491 let state = self.0.borrow();
1492 let top = state.bounds.top() - state.offset.borrow().y;
1493
1494 match state.child_bounds.binary_search_by(|bounds| {
1495 if top < bounds.top() {
1496 Ordering::Greater
1497 } else if top > bounds.bottom() {
1498 Ordering::Less
1499 } else {
1500 Ordering::Equal
1501 }
1502 }) {
1503 Ok(ix) => ix,
1504 Err(ix) => ix.min(state.child_bounds.len().saturating_sub(1)),
1505 }
1506 }
1507
1508 pub fn bounds_for_item(&self, ix: usize) -> Option<Bounds<Pixels>> {
1509 self.0.borrow().child_bounds.get(ix).cloned()
1510 }
1511
1512 /// scroll_to_item scrolls the minimal amount to ensure that the item is
1513 /// fully visible
1514 pub fn scroll_to_item(&self, ix: usize) {
1515 let state = self.0.borrow();
1516
1517 let Some(bounds) = state.child_bounds.get(ix) else {
1518 return;
1519 };
1520
1521 let scroll_offset = state.offset.borrow().y;
1522
1523 if bounds.top() + scroll_offset < state.bounds.top() {
1524 state.offset.borrow_mut().y = state.bounds.top() - bounds.top();
1525 } else if bounds.bottom() + scroll_offset > state.bounds.bottom() {
1526 state.offset.borrow_mut().y = state.bounds.bottom() - bounds.bottom();
1527 }
1528 }
1529
1530 pub fn logical_scroll_top(&self) -> (usize, Pixels) {
1531 let ix = self.top_item();
1532 let state = self.0.borrow();
1533
1534 if let Some(child_bounds) = state.child_bounds.get(ix) {
1535 (
1536 ix,
1537 child_bounds.top() + state.offset.borrow().y - state.bounds.top(),
1538 )
1539 } else {
1540 (ix, px(0.))
1541 }
1542 }
1543
1544 pub fn set_logical_scroll_top(&self, ix: usize, px: Pixels) {
1545 self.0.borrow_mut().requested_scroll_top = Some((ix, px));
1546 }
1547}