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: Box<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 = Some(Box::new(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: Box::new(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: Box::new(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 = Some(Box::new(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: Box::new(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 = Some(Box::new(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 = Some(Box::new(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 = Vec<FocusListener>;
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 DragEventListener = Box<dyn Fn(&MouseMoveEvent, &mut WindowContext) + 'static>;
563
564pub type ActionListener = Box<dyn Fn(&dyn Any, DispatchPhase, &mut WindowContext) + 'static>;
565
566pub fn div() -> Div {
567 Div {
568 interactivity: Interactivity::default(),
569 children: SmallVec::default(),
570 }
571}
572
573pub struct Div {
574 interactivity: Interactivity,
575 children: SmallVec<[AnyElement; 2]>,
576}
577
578impl Styled for Div {
579 fn style(&mut self) -> &mut StyleRefinement {
580 &mut self.interactivity.base_style
581 }
582}
583
584impl InteractiveElement for Div {
585 fn interactivity(&mut self) -> &mut Interactivity {
586 &mut self.interactivity
587 }
588}
589
590impl ParentElement for Div {
591 fn children_mut(&mut self) -> &mut SmallVec<[AnyElement; 2]> {
592 &mut self.children
593 }
594}
595
596impl Element for Div {
597 type State = DivState;
598
599 fn layout(
600 &mut self,
601 element_state: Option<Self::State>,
602 cx: &mut WindowContext,
603 ) -> (LayoutId, Self::State) {
604 let mut child_layout_ids = SmallVec::new();
605 let (layout_id, interactive_state) = self.interactivity.layout(
606 element_state.map(|s| s.interactive_state),
607 cx,
608 |style, cx| {
609 cx.with_text_style(style.text_style().cloned(), |cx| {
610 child_layout_ids = self
611 .children
612 .iter_mut()
613 .map(|child| child.layout(cx))
614 .collect::<SmallVec<_>>();
615 cx.request_layout(&style, child_layout_ids.iter().copied())
616 })
617 },
618 );
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; 2]>,
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: Box<StyleRefinement>,
732 pub focus_style: Option<Box<StyleRefinement>>,
733 pub in_focus_style: Option<Box<StyleRefinement>>,
734 pub hover_style: Option<Box<StyleRefinement>>,
735 pub group_hover_style: Option<GroupStyle>,
736 pub active_style: Option<Box<StyleRefinement>>,
737 pub group_active_style: Option<GroupStyle>,
738 pub drag_over_styles: Vec<(TypeId, StyleRefinement)>,
739 pub group_drag_over_styles: Vec<(TypeId, GroupStyle)>,
740 pub mouse_down_listeners: Vec<MouseDownListener>,
741 pub mouse_up_listeners: Vec<MouseUpListener>,
742 pub mouse_move_listeners: Vec<MouseMoveListener>,
743 pub scroll_wheel_listeners: Vec<ScrollWheelListener>,
744 pub key_down_listeners: Vec<KeyDownListener>,
745 pub key_up_listeners: Vec<KeyUpListener>,
746 pub action_listeners: Vec<(TypeId, ActionListener)>,
747 pub drop_listeners: Vec<(TypeId, Box<DropListener>)>,
748 pub click_listeners: Vec<ClickListener>,
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, Debug)]
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) && cx.was_top_layer(&point, &self.stacking_order)
763 }
764
765 pub fn drag_target_contains(&self, point: &Point<Pixels>, cx: &WindowContext) -> bool {
766 self.bounds.contains(point)
767 && cx.was_top_layer_under_active_drag(&point, &self.stacking_order)
768 }
769}
770
771impl Interactivity {
772 pub fn layout(
773 &mut self,
774 element_state: Option<InteractiveElementState>,
775 cx: &mut WindowContext,
776 f: impl FnOnce(Style, &mut WindowContext) -> LayoutId,
777 ) -> (LayoutId, InteractiveElementState) {
778 let mut element_state = element_state.unwrap_or_default();
779
780 // Ensure we store a focus handle in our element state if we're focusable.
781 // If there's an explicit focus handle we're tracking, use that. Otherwise
782 // create a new handle and store it in the element state, which lives for as
783 // as frames contain an element with this id.
784 if self.focusable {
785 element_state.focus_handle.get_or_insert_with(|| {
786 self.tracked_focus_handle
787 .clone()
788 .unwrap_or_else(|| cx.focus_handle())
789 });
790 }
791
792 if let Some(scroll_handle) = self.scroll_handle.as_ref() {
793 element_state.scroll_offset = Some(scroll_handle.0.borrow().offset.clone());
794 }
795
796 let style = self.compute_style(None, &mut element_state, cx);
797 let layout_id = f(style, cx);
798 (layout_id, element_state)
799 }
800
801 pub fn paint(
802 mut self,
803 bounds: Bounds<Pixels>,
804 content_size: Size<Pixels>,
805 element_state: &mut InteractiveElementState,
806 cx: &mut WindowContext,
807 f: impl FnOnce(Style, Point<Pixels>, &mut WindowContext),
808 ) {
809 let style = self.compute_style(Some(bounds), element_state, cx);
810
811 if style
812 .background
813 .as_ref()
814 .is_some_and(|fill| fill.color().is_some_and(|color| !color.is_transparent()))
815 {
816 cx.with_z_index(style.z_index.unwrap_or(0), |cx| cx.add_opaque_layer(bounds))
817 }
818
819 let interactive_bounds = Rc::new(InteractiveBounds {
820 bounds: bounds.intersect(&cx.content_mask().bounds),
821 stacking_order: cx.stacking_order().clone(),
822 });
823
824 if let Some(mouse_cursor) = style.mouse_cursor {
825 let mouse_position = &cx.mouse_position();
826 let hovered = interactive_bounds.visibly_contains(mouse_position, cx);
827 if hovered {
828 cx.set_cursor_style(mouse_cursor);
829 }
830 }
831
832 for listener in self.mouse_down_listeners.drain(..) {
833 let interactive_bounds = interactive_bounds.clone();
834 cx.on_mouse_event(move |event: &MouseDownEvent, phase, cx| {
835 listener(event, &*interactive_bounds, phase, cx);
836 })
837 }
838
839 for listener in self.mouse_up_listeners.drain(..) {
840 let interactive_bounds = interactive_bounds.clone();
841 cx.on_mouse_event(move |event: &MouseUpEvent, phase, cx| {
842 listener(event, &*interactive_bounds, phase, cx);
843 })
844 }
845
846 for listener in self.mouse_move_listeners.drain(..) {
847 let interactive_bounds = interactive_bounds.clone();
848 cx.on_mouse_event(move |event: &MouseMoveEvent, phase, cx| {
849 listener(event, &*interactive_bounds, phase, cx);
850 })
851 }
852
853 for listener in self.scroll_wheel_listeners.drain(..) {
854 let interactive_bounds = interactive_bounds.clone();
855 cx.on_mouse_event(move |event: &ScrollWheelEvent, phase, cx| {
856 listener(event, &*interactive_bounds, phase, cx);
857 })
858 }
859
860 let hover_group_bounds = self
861 .group_hover_style
862 .as_ref()
863 .and_then(|group_hover| GroupBounds::get(&group_hover.group, cx));
864
865 if let Some(group_bounds) = hover_group_bounds {
866 let hovered = group_bounds.contains(&cx.mouse_position());
867 cx.on_mouse_event(move |event: &MouseMoveEvent, phase, cx| {
868 if phase == DispatchPhase::Capture {
869 if group_bounds.contains(&event.position) != hovered {
870 cx.notify();
871 }
872 }
873 });
874 }
875
876 if self.hover_style.is_some()
877 || self.base_style.mouse_cursor.is_some()
878 || cx.active_drag.is_some() && !self.drag_over_styles.is_empty()
879 {
880 let bounds = bounds.intersect(&cx.content_mask().bounds);
881 let hovered = bounds.contains(&cx.mouse_position());
882 cx.on_mouse_event(move |event: &MouseMoveEvent, phase, cx| {
883 if phase == DispatchPhase::Capture {
884 if bounds.contains(&event.position) != hovered {
885 cx.notify();
886 }
887 }
888 });
889 }
890
891 if cx.active_drag.is_some() {
892 let drop_listeners = mem::take(&mut self.drop_listeners);
893 let interactive_bounds = interactive_bounds.clone();
894 if !drop_listeners.is_empty() {
895 cx.on_mouse_event(move |event: &MouseUpEvent, phase, cx| {
896 if phase == DispatchPhase::Bubble
897 && interactive_bounds.drag_target_contains(&event.position, cx)
898 {
899 if let Some(drag_state_type) =
900 cx.active_drag.as_ref().map(|drag| drag.view.entity_type())
901 {
902 for (drop_state_type, listener) in &drop_listeners {
903 if *drop_state_type == drag_state_type {
904 let drag = cx
905 .active_drag
906 .take()
907 .expect("checked for type drag state type above");
908
909 listener(drag.view.clone(), cx);
910 cx.notify();
911 cx.stop_propagation();
912 }
913 }
914 } else {
915 cx.active_drag = None;
916 }
917 }
918 });
919 }
920 }
921
922 let click_listeners = mem::take(&mut self.click_listeners);
923 let drag_listener = mem::take(&mut self.drag_listener);
924
925 if !click_listeners.is_empty() || drag_listener.is_some() {
926 let pending_mouse_down = element_state.pending_mouse_down.clone();
927 let mouse_down = pending_mouse_down.borrow().clone();
928 if let Some(mouse_down) = mouse_down {
929 if let Some(drag_listener) = drag_listener {
930 let active_state = element_state.clicked_state.clone();
931 let interactive_bounds = interactive_bounds.clone();
932
933 cx.on_mouse_event(move |event: &MouseMoveEvent, phase, cx| {
934 if cx.active_drag.is_some() {
935 if phase == DispatchPhase::Capture {
936 cx.notify();
937 }
938 } else if phase == DispatchPhase::Bubble
939 && interactive_bounds.visibly_contains(&event.position, cx)
940 && (event.position - mouse_down.position).magnitude() > DRAG_THRESHOLD
941 {
942 *active_state.borrow_mut() = ElementClickedState::default();
943 let cursor_offset = event.position - bounds.origin;
944 let drag = drag_listener(cursor_offset, cx);
945 cx.active_drag = Some(drag);
946 cx.notify();
947 cx.stop_propagation();
948 }
949 });
950 }
951
952 let interactive_bounds = interactive_bounds.clone();
953 cx.on_mouse_event(move |event: &MouseUpEvent, phase, cx| {
954 if phase == DispatchPhase::Bubble
955 && interactive_bounds.visibly_contains(&event.position, cx)
956 {
957 let mouse_click = ClickEvent {
958 down: mouse_down.clone(),
959 up: event.clone(),
960 };
961 for listener in &click_listeners {
962 listener(&mouse_click, cx);
963 }
964 }
965 *pending_mouse_down.borrow_mut() = None;
966 cx.notify();
967 });
968 } else {
969 let interactive_bounds = interactive_bounds.clone();
970 cx.on_mouse_event(move |event: &MouseDownEvent, phase, cx| {
971 if phase == DispatchPhase::Bubble
972 && event.button == MouseButton::Left
973 && interactive_bounds.visibly_contains(&event.position, cx)
974 {
975 *pending_mouse_down.borrow_mut() = Some(event.clone());
976 cx.notify();
977 }
978 });
979 }
980 }
981
982 if let Some(hover_listener) = self.hover_listener.take() {
983 let was_hovered = element_state.hover_state.clone();
984 let has_mouse_down = element_state.pending_mouse_down.clone();
985 let interactive_bounds = interactive_bounds.clone();
986
987 cx.on_mouse_event(move |event: &MouseMoveEvent, phase, cx| {
988 if phase != DispatchPhase::Bubble {
989 return;
990 }
991 let is_hovered = interactive_bounds.visibly_contains(&event.position, cx)
992 && has_mouse_down.borrow().is_none();
993 let mut was_hovered = was_hovered.borrow_mut();
994
995 if is_hovered != was_hovered.clone() {
996 *was_hovered = is_hovered;
997 drop(was_hovered);
998
999 hover_listener(&is_hovered, cx);
1000 }
1001 });
1002 }
1003
1004 if let Some(tooltip_builder) = self.tooltip_builder.take() {
1005 let active_tooltip = element_state.active_tooltip.clone();
1006 let pending_mouse_down = element_state.pending_mouse_down.clone();
1007 let interactive_bounds = interactive_bounds.clone();
1008
1009 cx.on_mouse_event(move |event: &MouseMoveEvent, phase, cx| {
1010 let is_hovered = interactive_bounds.visibly_contains(&event.position, cx)
1011 && pending_mouse_down.borrow().is_none();
1012 if !is_hovered {
1013 active_tooltip.borrow_mut().take();
1014 return;
1015 }
1016
1017 if phase != DispatchPhase::Bubble {
1018 return;
1019 }
1020
1021 if active_tooltip.borrow().is_none() {
1022 let task = cx.spawn({
1023 let active_tooltip = active_tooltip.clone();
1024 let tooltip_builder = tooltip_builder.clone();
1025
1026 move |mut cx| async move {
1027 cx.background_executor().timer(TOOLTIP_DELAY).await;
1028 cx.update(|_, cx| {
1029 active_tooltip.borrow_mut().replace(ActiveTooltip {
1030 tooltip: Some(AnyTooltip {
1031 view: tooltip_builder(cx),
1032 cursor_offset: cx.mouse_position(),
1033 }),
1034 _task: None,
1035 });
1036 cx.notify();
1037 })
1038 .ok();
1039 }
1040 });
1041 active_tooltip.borrow_mut().replace(ActiveTooltip {
1042 tooltip: None,
1043 _task: Some(task),
1044 });
1045 }
1046 });
1047
1048 let active_tooltip = element_state.active_tooltip.clone();
1049 cx.on_mouse_event(move |_: &MouseDownEvent, _, _| {
1050 active_tooltip.borrow_mut().take();
1051 });
1052
1053 if let Some(active_tooltip) = element_state.active_tooltip.borrow().as_ref() {
1054 if active_tooltip.tooltip.is_some() {
1055 cx.active_tooltip = active_tooltip.tooltip.clone()
1056 }
1057 }
1058 }
1059
1060 let active_state = element_state.clicked_state.clone();
1061 if !active_state.borrow().is_clicked() {
1062 cx.on_mouse_event(move |_: &MouseUpEvent, phase, cx| {
1063 if phase == DispatchPhase::Capture {
1064 *active_state.borrow_mut() = ElementClickedState::default();
1065 cx.notify();
1066 }
1067 });
1068 } else {
1069 let active_group_bounds = self
1070 .group_active_style
1071 .as_ref()
1072 .and_then(|group_active| GroupBounds::get(&group_active.group, cx));
1073 let interactive_bounds = interactive_bounds.clone();
1074 cx.on_mouse_event(move |down: &MouseDownEvent, phase, cx| {
1075 if phase == DispatchPhase::Bubble {
1076 let group =
1077 active_group_bounds.map_or(false, |bounds| bounds.contains(&down.position));
1078 let element = interactive_bounds.visibly_contains(&down.position, cx);
1079 if group || element {
1080 *active_state.borrow_mut() = ElementClickedState { group, element };
1081 cx.notify();
1082 }
1083 }
1084 });
1085 }
1086
1087 let overflow = style.overflow;
1088 if overflow.x == Overflow::Scroll || overflow.y == Overflow::Scroll {
1089 let scroll_offset = element_state
1090 .scroll_offset
1091 .get_or_insert_with(Rc::default)
1092 .clone();
1093 let line_height = cx.line_height();
1094 let scroll_max = (content_size - bounds.size).max(&Size::default());
1095 let interactive_bounds = interactive_bounds.clone();
1096
1097 cx.on_mouse_event(move |event: &ScrollWheelEvent, phase, cx| {
1098 if phase == DispatchPhase::Bubble
1099 && interactive_bounds.visibly_contains(&event.position, cx)
1100 {
1101 let mut scroll_offset = scroll_offset.borrow_mut();
1102 let old_scroll_offset = *scroll_offset;
1103 let delta = event.delta.pixel_delta(line_height);
1104
1105 if overflow.x == Overflow::Scroll {
1106 scroll_offset.x =
1107 (scroll_offset.x + delta.x).clamp(-scroll_max.width, px(0.));
1108 }
1109
1110 if overflow.y == Overflow::Scroll {
1111 scroll_offset.y =
1112 (scroll_offset.y + delta.y).clamp(-scroll_max.height, px(0.));
1113 }
1114
1115 if *scroll_offset != old_scroll_offset {
1116 cx.notify();
1117 cx.stop_propagation();
1118 }
1119 }
1120 });
1121 }
1122
1123 if let Some(group) = self.group.clone() {
1124 GroupBounds::push(group, bounds, cx);
1125 }
1126
1127 let scroll_offset = element_state
1128 .scroll_offset
1129 .as_ref()
1130 .map(|scroll_offset| *scroll_offset.borrow());
1131
1132 cx.with_key_dispatch(
1133 self.key_context.clone(),
1134 element_state.focus_handle.clone(),
1135 |_, cx| {
1136 for listener in self.key_down_listeners.drain(..) {
1137 cx.on_key_event(move |event: &KeyDownEvent, phase, cx| {
1138 listener(event, phase, cx);
1139 })
1140 }
1141
1142 for listener in self.key_up_listeners.drain(..) {
1143 cx.on_key_event(move |event: &KeyUpEvent, phase, cx| {
1144 listener(event, phase, cx);
1145 })
1146 }
1147
1148 for (action_type, listener) in self.action_listeners {
1149 cx.on_action(action_type, listener)
1150 }
1151
1152 if let Some(focus_handle) = element_state.focus_handle.as_ref() {
1153 for listener in self.focus_listeners {
1154 let focus_handle = focus_handle.clone();
1155 cx.on_focus_changed(move |event, cx| listener(&focus_handle, event, cx));
1156 }
1157 }
1158
1159 f(style, scroll_offset.unwrap_or_default(), cx)
1160 },
1161 );
1162
1163 if let Some(group) = self.group.as_ref() {
1164 GroupBounds::pop(group, cx);
1165 }
1166 }
1167
1168 pub fn compute_style(
1169 &self,
1170 bounds: Option<Bounds<Pixels>>,
1171 element_state: &mut InteractiveElementState,
1172 cx: &mut WindowContext,
1173 ) -> Style {
1174 let mut style = Style::default();
1175 style.refine(&self.base_style);
1176
1177 if let Some(focus_handle) = self.tracked_focus_handle.as_ref() {
1178 if let Some(in_focus_style) = self.in_focus_style.as_ref() {
1179 if focus_handle.within_focused(cx) {
1180 style.refine(in_focus_style);
1181 }
1182 }
1183
1184 if let Some(focus_style) = self.focus_style.as_ref() {
1185 if focus_handle.is_focused(cx) {
1186 style.refine(focus_style);
1187 }
1188 }
1189 }
1190
1191 if let Some(bounds) = bounds {
1192 let mouse_position = cx.mouse_position();
1193 if let Some(group_hover) = self.group_hover_style.as_ref() {
1194 if let Some(group_bounds) = GroupBounds::get(&group_hover.group, cx) {
1195 if group_bounds.contains(&mouse_position)
1196 && cx.was_top_layer(&mouse_position, cx.stacking_order())
1197 {
1198 style.refine(&group_hover.style);
1199 }
1200 }
1201 }
1202 if let Some(hover_style) = self.hover_style.as_ref() {
1203 if bounds
1204 .intersect(&cx.content_mask().bounds)
1205 .contains(&mouse_position)
1206 && cx.was_top_layer(&mouse_position, cx.stacking_order())
1207 {
1208 style.refine(hover_style);
1209 }
1210 }
1211
1212 if let Some(drag) = cx.active_drag.take() {
1213 for (state_type, group_drag_style) in &self.group_drag_over_styles {
1214 if let Some(group_bounds) = GroupBounds::get(&group_drag_style.group, cx) {
1215 if *state_type == drag.view.entity_type()
1216 && group_bounds.contains(&mouse_position)
1217 {
1218 style.refine(&group_drag_style.style);
1219 }
1220 }
1221 }
1222
1223 for (state_type, drag_over_style) in &self.drag_over_styles {
1224 if *state_type == drag.view.entity_type()
1225 && bounds
1226 .intersect(&cx.content_mask().bounds)
1227 .contains(&mouse_position)
1228 {
1229 style.refine(drag_over_style);
1230 }
1231 }
1232
1233 cx.active_drag = Some(drag);
1234 }
1235 }
1236
1237 let clicked_state = element_state.clicked_state.borrow();
1238 if clicked_state.group {
1239 if let Some(group) = self.group_active_style.as_ref() {
1240 style.refine(&group.style)
1241 }
1242 }
1243
1244 if let Some(active_style) = self.active_style.as_ref() {
1245 if clicked_state.element {
1246 style.refine(active_style)
1247 }
1248 }
1249
1250 style
1251 }
1252}
1253
1254impl Default for Interactivity {
1255 fn default() -> Self {
1256 Self {
1257 element_id: None,
1258 key_context: None,
1259 focusable: false,
1260 tracked_focus_handle: None,
1261 scroll_handle: None,
1262 focus_listeners: Vec::default(),
1263 // scroll_offset: Point::default(),
1264 group: None,
1265 base_style: Box::new(StyleRefinement::default()),
1266 focus_style: None,
1267 in_focus_style: None,
1268 hover_style: None,
1269 group_hover_style: None,
1270 active_style: None,
1271 group_active_style: None,
1272 drag_over_styles: Vec::new(),
1273 group_drag_over_styles: Vec::new(),
1274 mouse_down_listeners: Vec::new(),
1275 mouse_up_listeners: Vec::new(),
1276 mouse_move_listeners: Vec::new(),
1277 scroll_wheel_listeners: Vec::new(),
1278 key_down_listeners: Vec::new(),
1279 key_up_listeners: Vec::new(),
1280 action_listeners: Vec::new(),
1281 drop_listeners: Vec::new(),
1282 click_listeners: Vec::new(),
1283 drag_listener: None,
1284 hover_listener: None,
1285 tooltip_builder: None,
1286 }
1287 }
1288}
1289
1290#[derive(Default)]
1291pub struct InteractiveElementState {
1292 pub focus_handle: Option<FocusHandle>,
1293 pub clicked_state: Rc<RefCell<ElementClickedState>>,
1294 pub hover_state: Rc<RefCell<bool>>,
1295 pub pending_mouse_down: Rc<RefCell<Option<MouseDownEvent>>>,
1296 pub scroll_offset: Option<Rc<RefCell<Point<Pixels>>>>,
1297 pub active_tooltip: Rc<RefCell<Option<ActiveTooltip>>>,
1298}
1299
1300pub struct ActiveTooltip {
1301 tooltip: Option<AnyTooltip>,
1302 _task: Option<Task<()>>,
1303}
1304
1305/// Whether or not the element or a group that contains it is clicked by the mouse.
1306#[derive(Copy, Clone, Default, Eq, PartialEq)]
1307pub struct ElementClickedState {
1308 pub group: bool,
1309 pub element: bool,
1310}
1311
1312impl ElementClickedState {
1313 fn is_clicked(&self) -> bool {
1314 self.group || self.element
1315 }
1316}
1317
1318#[derive(Default)]
1319pub struct GroupBounds(HashMap<SharedString, SmallVec<[Bounds<Pixels>; 1]>>);
1320
1321impl GroupBounds {
1322 pub fn get(name: &SharedString, cx: &mut AppContext) -> Option<Bounds<Pixels>> {
1323 cx.default_global::<Self>()
1324 .0
1325 .get(name)
1326 .and_then(|bounds_stack| bounds_stack.last())
1327 .cloned()
1328 }
1329
1330 pub fn push(name: SharedString, bounds: Bounds<Pixels>, cx: &mut AppContext) {
1331 cx.default_global::<Self>()
1332 .0
1333 .entry(name)
1334 .or_default()
1335 .push(bounds);
1336 }
1337
1338 pub fn pop(name: &SharedString, cx: &mut AppContext) {
1339 cx.default_global::<Self>().0.get_mut(name).unwrap().pop();
1340 }
1341}
1342
1343pub struct Focusable<E> {
1344 pub element: E,
1345}
1346
1347impl<E: InteractiveElement> FocusableElement for Focusable<E> {}
1348
1349impl<E> InteractiveElement for Focusable<E>
1350where
1351 E: InteractiveElement,
1352{
1353 fn interactivity(&mut self) -> &mut Interactivity {
1354 self.element.interactivity()
1355 }
1356}
1357
1358impl<E: StatefulInteractiveElement> StatefulInteractiveElement for Focusable<E> {}
1359
1360impl<E> Styled for Focusable<E>
1361where
1362 E: Styled,
1363{
1364 fn style(&mut self) -> &mut StyleRefinement {
1365 self.element.style()
1366 }
1367}
1368
1369impl<E> Element for Focusable<E>
1370where
1371 E: Element,
1372{
1373 type State = E::State;
1374
1375 fn layout(
1376 &mut self,
1377 state: Option<Self::State>,
1378 cx: &mut WindowContext,
1379 ) -> (LayoutId, Self::State) {
1380 self.element.layout(state, cx)
1381 }
1382
1383 fn paint(self, bounds: Bounds<Pixels>, state: &mut Self::State, cx: &mut WindowContext) {
1384 self.element.paint(bounds, state, cx)
1385 }
1386}
1387
1388impl<E> IntoElement for Focusable<E>
1389where
1390 E: Element,
1391{
1392 type Element = E;
1393
1394 fn element_id(&self) -> Option<ElementId> {
1395 self.element.element_id()
1396 }
1397
1398 fn into_element(self) -> Self::Element {
1399 self.element
1400 }
1401}
1402
1403impl<E> ParentElement for Focusable<E>
1404where
1405 E: ParentElement,
1406{
1407 fn children_mut(&mut self) -> &mut SmallVec<[AnyElement; 2]> {
1408 self.element.children_mut()
1409 }
1410}
1411
1412pub struct Stateful<E> {
1413 element: E,
1414}
1415
1416impl<E> Styled for Stateful<E>
1417where
1418 E: Styled,
1419{
1420 fn style(&mut self) -> &mut StyleRefinement {
1421 self.element.style()
1422 }
1423}
1424
1425impl<E> StatefulInteractiveElement for Stateful<E>
1426where
1427 E: Element,
1428 Self: InteractiveElement,
1429{
1430}
1431
1432impl<E> InteractiveElement for Stateful<E>
1433where
1434 E: InteractiveElement,
1435{
1436 fn interactivity(&mut self) -> &mut Interactivity {
1437 self.element.interactivity()
1438 }
1439}
1440
1441impl<E: FocusableElement> FocusableElement for Stateful<E> {}
1442
1443impl<E> Element for Stateful<E>
1444where
1445 E: Element,
1446{
1447 type State = E::State;
1448
1449 fn layout(
1450 &mut self,
1451 state: Option<Self::State>,
1452 cx: &mut WindowContext,
1453 ) -> (LayoutId, Self::State) {
1454 self.element.layout(state, cx)
1455 }
1456
1457 fn paint(self, bounds: Bounds<Pixels>, state: &mut Self::State, cx: &mut WindowContext) {
1458 self.element.paint(bounds, state, cx)
1459 }
1460}
1461
1462impl<E> IntoElement for Stateful<E>
1463where
1464 E: Element,
1465{
1466 type Element = Self;
1467
1468 fn element_id(&self) -> Option<ElementId> {
1469 self.element.element_id()
1470 }
1471
1472 fn into_element(self) -> Self::Element {
1473 self
1474 }
1475}
1476
1477impl<E> ParentElement for Stateful<E>
1478where
1479 E: ParentElement,
1480{
1481 fn children_mut(&mut self) -> &mut SmallVec<[AnyElement; 2]> {
1482 self.element.children_mut()
1483 }
1484}
1485
1486#[derive(Default)]
1487struct ScrollHandleState {
1488 // not great to have the nested rc's...
1489 offset: Rc<RefCell<Point<Pixels>>>,
1490 bounds: Bounds<Pixels>,
1491 child_bounds: Vec<Bounds<Pixels>>,
1492 requested_scroll_top: Option<(usize, Pixels)>,
1493}
1494
1495#[derive(Clone)]
1496pub struct ScrollHandle(Rc<RefCell<ScrollHandleState>>);
1497
1498impl ScrollHandle {
1499 pub fn new() -> Self {
1500 Self(Rc::default())
1501 }
1502
1503 pub fn offset(&self) -> Point<Pixels> {
1504 self.0.borrow().offset.borrow().clone()
1505 }
1506
1507 pub fn top_item(&self) -> usize {
1508 let state = self.0.borrow();
1509 let top = state.bounds.top() - state.offset.borrow().y;
1510
1511 match state.child_bounds.binary_search_by(|bounds| {
1512 if top < bounds.top() {
1513 Ordering::Greater
1514 } else if top > bounds.bottom() {
1515 Ordering::Less
1516 } else {
1517 Ordering::Equal
1518 }
1519 }) {
1520 Ok(ix) => ix,
1521 Err(ix) => ix.min(state.child_bounds.len().saturating_sub(1)),
1522 }
1523 }
1524
1525 pub fn bounds_for_item(&self, ix: usize) -> Option<Bounds<Pixels>> {
1526 self.0.borrow().child_bounds.get(ix).cloned()
1527 }
1528
1529 /// scroll_to_item scrolls the minimal amount to ensure that the item is
1530 /// fully visible
1531 pub fn scroll_to_item(&self, ix: usize) {
1532 let state = self.0.borrow();
1533
1534 let Some(bounds) = state.child_bounds.get(ix) else {
1535 return;
1536 };
1537
1538 let scroll_offset = state.offset.borrow().y;
1539
1540 if bounds.top() + scroll_offset < state.bounds.top() {
1541 state.offset.borrow_mut().y = state.bounds.top() - bounds.top();
1542 } else if bounds.bottom() + scroll_offset > state.bounds.bottom() {
1543 state.offset.borrow_mut().y = state.bounds.bottom() - bounds.bottom();
1544 }
1545 }
1546
1547 pub fn logical_scroll_top(&self) -> (usize, Pixels) {
1548 let ix = self.top_item();
1549 let state = self.0.borrow();
1550
1551 if let Some(child_bounds) = state.child_bounds.get(ix) {
1552 (
1553 ix,
1554 child_bounds.top() + state.offset.borrow().y - state.bounds.top(),
1555 )
1556 } else {
1557 (ix, px(0.))
1558 }
1559 }
1560
1561 pub fn set_logical_scroll_top(&self, ix: usize, px: Pixels) {
1562 self.0.borrow_mut().requested_scroll_top = Some((ix, px));
1563 }
1564}