1use crate::{
   2    point, px, Action, AnyDrag, AnyElement, AnyTooltip, AnyView, AppContext, BorrowAppContext,
   3    BorrowWindow, Bounds, ClickEvent, DispatchPhase, Element, ElementId, FocusHandle, IntoElement,
   4    IsZero, 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};
   9
  10use collections::HashMap;
  11use refineable::Refineable;
  12use smallvec::SmallVec;
  13use std::{
  14    any::{Any, TypeId},
  15    cell::RefCell,
  16    cmp::Ordering,
  17    fmt::Debug,
  18    marker::PhantomData,
  19    mem,
  20    rc::Rc,
  21    time::Duration,
  22};
  23use taffy::style::Overflow;
  24use util::ResultExt;
  25
  26const DRAG_THRESHOLD: f64 = 2.;
  27const TOOLTIP_DELAY: Duration = Duration::from_millis(500);
  28
  29pub struct GroupStyle {
  30    pub group: SharedString,
  31    pub style: Box<StyleRefinement>,
  32}
  33
  34pub struct DragMoveEvent<T> {
  35    pub event: MouseMoveEvent,
  36    pub bounds: Bounds<Pixels>,
  37    drag: PhantomData<T>,
  38}
  39
  40impl<T: 'static> DragMoveEvent<T> {
  41    pub fn drag<'b>(&self, cx: &'b AppContext) -> &'b T {
  42        cx.active_drag
  43            .as_ref()
  44            .and_then(|drag| drag.value.downcast_ref::<T>())
  45            .expect("DragMoveEvent is only valid when the stored active drag is of the same type.")
  46    }
  47}
  48
  49impl Interactivity {
  50    pub fn on_mouse_down(
  51        &mut self,
  52        button: MouseButton,
  53        listener: impl Fn(&MouseDownEvent, &mut WindowContext) + 'static,
  54    ) {
  55        self.mouse_down_listeners
  56            .push(Box::new(move |event, bounds, phase, cx| {
  57                if phase == DispatchPhase::Bubble
  58                    && event.button == button
  59                    && bounds.visibly_contains(&event.position, cx)
  60                {
  61                    (listener)(event, cx)
  62                }
  63            }));
  64    }
  65
  66    pub fn capture_any_mouse_down(
  67        &mut self,
  68        listener: impl Fn(&MouseDownEvent, &mut WindowContext) + 'static,
  69    ) {
  70        self.mouse_down_listeners
  71            .push(Box::new(move |event, bounds, phase, cx| {
  72                if phase == DispatchPhase::Capture && bounds.visibly_contains(&event.position, cx) {
  73                    (listener)(event, cx)
  74                }
  75            }));
  76    }
  77
  78    pub fn on_any_mouse_down(
  79        &mut self,
  80        listener: impl Fn(&MouseDownEvent, &mut WindowContext) + 'static,
  81    ) {
  82        self.mouse_down_listeners
  83            .push(Box::new(move |event, bounds, phase, cx| {
  84                if phase == DispatchPhase::Bubble && bounds.visibly_contains(&event.position, cx) {
  85                    (listener)(event, cx)
  86                }
  87            }));
  88    }
  89
  90    pub fn on_mouse_up(
  91        &mut self,
  92        button: MouseButton,
  93        listener: impl Fn(&MouseUpEvent, &mut WindowContext) + 'static,
  94    ) {
  95        self.mouse_up_listeners
  96            .push(Box::new(move |event, bounds, phase, cx| {
  97                if phase == DispatchPhase::Bubble
  98                    && event.button == button
  99                    && bounds.visibly_contains(&event.position, cx)
 100                {
 101                    (listener)(event, cx)
 102                }
 103            }));
 104    }
 105
 106    pub fn capture_any_mouse_up(
 107        &mut self,
 108        listener: impl Fn(&MouseUpEvent, &mut WindowContext) + 'static,
 109    ) {
 110        self.mouse_up_listeners
 111            .push(Box::new(move |event, bounds, phase, cx| {
 112                if phase == DispatchPhase::Capture && bounds.visibly_contains(&event.position, cx) {
 113                    (listener)(event, cx)
 114                }
 115            }));
 116    }
 117
 118    pub fn on_any_mouse_up(
 119        &mut self,
 120        listener: impl Fn(&MouseUpEvent, &mut WindowContext) + 'static,
 121    ) {
 122        self.mouse_up_listeners
 123            .push(Box::new(move |event, bounds, phase, cx| {
 124                if phase == DispatchPhase::Bubble && bounds.visibly_contains(&event.position, cx) {
 125                    (listener)(event, cx)
 126                }
 127            }));
 128    }
 129
 130    pub fn on_mouse_down_out(
 131        &mut self,
 132        listener: impl Fn(&MouseDownEvent, &mut WindowContext) + 'static,
 133    ) {
 134        self.mouse_down_listeners
 135            .push(Box::new(move |event, bounds, phase, cx| {
 136                if phase == DispatchPhase::Capture && !bounds.visibly_contains(&event.position, cx)
 137                {
 138                    (listener)(event, cx)
 139                }
 140            }));
 141    }
 142
 143    pub fn on_mouse_up_out(
 144        &mut self,
 145        button: MouseButton,
 146        listener: impl Fn(&MouseUpEvent, &mut WindowContext) + 'static,
 147    ) {
 148        self.mouse_up_listeners
 149            .push(Box::new(move |event, bounds, phase, cx| {
 150                if phase == DispatchPhase::Capture
 151                    && event.button == button
 152                    && !bounds.visibly_contains(&event.position, cx)
 153                {
 154                    (listener)(event, cx);
 155                }
 156            }));
 157    }
 158
 159    pub fn on_mouse_move(
 160        &mut self,
 161        listener: impl Fn(&MouseMoveEvent, &mut WindowContext) + 'static,
 162    ) {
 163        self.mouse_move_listeners
 164            .push(Box::new(move |event, bounds, phase, cx| {
 165                if phase == DispatchPhase::Bubble && bounds.visibly_contains(&event.position, cx) {
 166                    (listener)(event, cx);
 167                }
 168            }));
 169    }
 170
 171    pub fn on_drag_move<T>(
 172        &mut self,
 173        listener: impl Fn(&DragMoveEvent<T>, &mut WindowContext) + 'static,
 174    ) where
 175        T: 'static,
 176    {
 177        self.mouse_move_listeners
 178            .push(Box::new(move |event, bounds, phase, cx| {
 179                if phase == DispatchPhase::Capture
 180                    && cx
 181                        .active_drag
 182                        .as_ref()
 183                        .is_some_and(|drag| drag.value.as_ref().type_id() == TypeId::of::<T>())
 184                {
 185                    (listener)(
 186                        &DragMoveEvent {
 187                            event: event.clone(),
 188                            bounds: bounds.bounds,
 189                            drag: PhantomData,
 190                        },
 191                        cx,
 192                    );
 193                }
 194            }));
 195    }
 196
 197    pub fn on_scroll_wheel(
 198        &mut self,
 199        listener: impl Fn(&ScrollWheelEvent, &mut WindowContext) + 'static,
 200    ) {
 201        self.scroll_wheel_listeners
 202            .push(Box::new(move |event, bounds, phase, cx| {
 203                if phase == DispatchPhase::Bubble && bounds.visibly_contains(&event.position, cx) {
 204                    (listener)(event, cx);
 205                }
 206            }));
 207    }
 208
 209    pub fn capture_action<A: Action>(
 210        &mut self,
 211        listener: impl Fn(&A, &mut WindowContext) + 'static,
 212    ) {
 213        self.action_listeners.push((
 214            TypeId::of::<A>(),
 215            Box::new(move |action, phase, cx| {
 216                let action = action.downcast_ref().unwrap();
 217                if phase == DispatchPhase::Capture {
 218                    (listener)(action, cx)
 219                }
 220            }),
 221        ));
 222    }
 223
 224    pub fn on_action<A: Action>(&mut self, listener: impl Fn(&A, &mut WindowContext) + 'static) {
 225        self.action_listeners.push((
 226            TypeId::of::<A>(),
 227            Box::new(move |action, phase, cx| {
 228                let action = action.downcast_ref().unwrap();
 229                if phase == DispatchPhase::Bubble {
 230                    (listener)(action, cx)
 231                }
 232            }),
 233        ));
 234    }
 235
 236    pub fn on_boxed_action(
 237        &mut self,
 238        action: &dyn Action,
 239        listener: impl Fn(&Box<dyn Action>, &mut WindowContext) + 'static,
 240    ) {
 241        let action = action.boxed_clone();
 242        self.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    }
 251
 252    pub fn on_key_down(&mut self, listener: impl Fn(&KeyDownEvent, &mut WindowContext) + 'static) {
 253        self.key_down_listeners
 254            .push(Box::new(move |event, phase, cx| {
 255                if phase == DispatchPhase::Bubble {
 256                    (listener)(event, cx)
 257                }
 258            }));
 259    }
 260
 261    pub fn capture_key_down(
 262        &mut self,
 263        listener: impl Fn(&KeyDownEvent, &mut WindowContext) + 'static,
 264    ) {
 265        self.key_down_listeners
 266            .push(Box::new(move |event, phase, cx| {
 267                if phase == DispatchPhase::Capture {
 268                    listener(event, cx)
 269                }
 270            }));
 271    }
 272
 273    pub fn on_key_up(&mut self, listener: impl Fn(&KeyUpEvent, &mut WindowContext) + 'static) {
 274        self.key_up_listeners
 275            .push(Box::new(move |event, phase, cx| {
 276                if phase == DispatchPhase::Bubble {
 277                    listener(event, cx)
 278                }
 279            }));
 280    }
 281
 282    pub fn capture_key_up(&mut self, listener: impl Fn(&KeyUpEvent, &mut WindowContext) + 'static) {
 283        self.key_up_listeners
 284            .push(Box::new(move |event, phase, cx| {
 285                if phase == DispatchPhase::Capture {
 286                    listener(event, cx)
 287                }
 288            }));
 289    }
 290
 291    pub fn on_drop<T: 'static>(&mut self, listener: impl Fn(&T, &mut WindowContext) + 'static) {
 292        self.drop_listeners.push((
 293            TypeId::of::<T>(),
 294            Box::new(move |dragged_value, cx| {
 295                listener(dragged_value.downcast_ref().unwrap(), cx);
 296            }),
 297        ));
 298    }
 299
 300    pub fn can_drop(&mut self, predicate: impl Fn(&dyn Any, &mut WindowContext) -> bool + 'static) {
 301        self.can_drop_predicate = Some(Box::new(predicate));
 302    }
 303
 304    pub fn on_click(&mut self, listener: impl Fn(&ClickEvent, &mut WindowContext) + 'static)
 305    where
 306        Self: Sized,
 307    {
 308        self.click_listeners
 309            .push(Box::new(move |event, cx| listener(event, cx)));
 310    }
 311
 312    pub fn on_drag<T, W>(
 313        &mut self,
 314        value: T,
 315        constructor: impl Fn(&T, &mut WindowContext) -> View<W> + 'static,
 316    ) where
 317        Self: Sized,
 318        T: 'static,
 319        W: 'static + Render,
 320    {
 321        debug_assert!(
 322            self.drag_listener.is_none(),
 323            "calling on_drag more than once on the same element is not supported"
 324        );
 325        self.drag_listener = Some((
 326            Box::new(value),
 327            Box::new(move |value, cx| constructor(value.downcast_ref().unwrap(), cx).into()),
 328        ));
 329    }
 330
 331    pub fn on_hover(&mut self, listener: impl Fn(&bool, &mut WindowContext) + 'static)
 332    where
 333        Self: Sized,
 334    {
 335        debug_assert!(
 336            self.hover_listener.is_none(),
 337            "calling on_hover more than once on the same element is not supported"
 338        );
 339        self.hover_listener = Some(Box::new(listener));
 340    }
 341
 342    pub fn tooltip(&mut self, build_tooltip: impl Fn(&mut WindowContext) -> AnyView + 'static)
 343    where
 344        Self: Sized,
 345    {
 346        debug_assert!(
 347            self.tooltip_builder.is_none(),
 348            "calling tooltip more than once on the same element is not supported"
 349        );
 350        self.tooltip_builder = Some(Rc::new(build_tooltip));
 351    }
 352
 353    pub fn block_mouse(&mut self) {
 354        self.block_mouse = true;
 355    }
 356}
 357
 358pub trait InteractiveElement: Sized {
 359    fn interactivity(&mut self) -> &mut Interactivity;
 360
 361    fn group(mut self, group: impl Into<SharedString>) -> Self {
 362        self.interactivity().group = Some(group.into());
 363        self
 364    }
 365
 366    fn id(mut self, id: impl Into<ElementId>) -> Stateful<Self> {
 367        self.interactivity().element_id = Some(id.into());
 368
 369        Stateful { element: self }
 370    }
 371
 372    fn track_focus(mut self, focus_handle: &FocusHandle) -> Focusable<Self> {
 373        self.interactivity().focusable = true;
 374        self.interactivity().tracked_focus_handle = Some(focus_handle.clone());
 375        Focusable { element: self }
 376    }
 377
 378    fn key_context<C, E>(mut self, key_context: C) -> Self
 379    where
 380        C: TryInto<KeyContext, Error = E>,
 381        E: Debug,
 382    {
 383        if let Some(key_context) = key_context.try_into().log_err() {
 384            self.interactivity().key_context = Some(key_context);
 385        }
 386        self
 387    }
 388
 389    fn hover(mut self, f: impl FnOnce(StyleRefinement) -> StyleRefinement) -> Self {
 390        debug_assert!(
 391            self.interactivity().hover_style.is_none(),
 392            "hover style already set"
 393        );
 394        self.interactivity().hover_style = Some(Box::new(f(StyleRefinement::default())));
 395        self
 396    }
 397
 398    fn group_hover(
 399        mut self,
 400        group_name: impl Into<SharedString>,
 401        f: impl FnOnce(StyleRefinement) -> StyleRefinement,
 402    ) -> Self {
 403        self.interactivity().group_hover_style = Some(GroupStyle {
 404            group: group_name.into(),
 405            style: Box::new(f(StyleRefinement::default())),
 406        });
 407        self
 408    }
 409
 410    fn on_mouse_down(
 411        mut self,
 412        button: MouseButton,
 413        listener: impl Fn(&MouseDownEvent, &mut WindowContext) + 'static,
 414    ) -> Self {
 415        self.interactivity().on_mouse_down(button, listener);
 416        self
 417    }
 418
 419    fn capture_any_mouse_down(
 420        mut self,
 421        listener: impl Fn(&MouseDownEvent, &mut WindowContext) + 'static,
 422    ) -> Self {
 423        self.interactivity().capture_any_mouse_down(listener);
 424        self
 425    }
 426
 427    fn on_any_mouse_down(
 428        mut self,
 429        listener: impl Fn(&MouseDownEvent, &mut WindowContext) + 'static,
 430    ) -> Self {
 431        self.interactivity().on_any_mouse_down(listener);
 432        self
 433    }
 434
 435    fn on_mouse_up(
 436        mut self,
 437        button: MouseButton,
 438        listener: impl Fn(&MouseUpEvent, &mut WindowContext) + 'static,
 439    ) -> Self {
 440        self.interactivity().on_mouse_up(button, listener);
 441        self
 442    }
 443
 444    fn capture_any_mouse_up(
 445        mut self,
 446        listener: impl Fn(&MouseUpEvent, &mut WindowContext) + 'static,
 447    ) -> Self {
 448        self.interactivity().capture_any_mouse_up(listener);
 449        self
 450    }
 451
 452    fn on_mouse_down_out(
 453        mut self,
 454        listener: impl Fn(&MouseDownEvent, &mut WindowContext) + 'static,
 455    ) -> Self {
 456        self.interactivity().on_mouse_down_out(listener);
 457        self
 458    }
 459
 460    fn on_mouse_up_out(
 461        mut self,
 462        button: MouseButton,
 463        listener: impl Fn(&MouseUpEvent, &mut WindowContext) + 'static,
 464    ) -> Self {
 465        self.interactivity().on_mouse_up_out(button, listener);
 466        self
 467    }
 468
 469    fn on_mouse_move(
 470        mut self,
 471        listener: impl Fn(&MouseMoveEvent, &mut WindowContext) + 'static,
 472    ) -> Self {
 473        self.interactivity().on_mouse_move(listener);
 474        self
 475    }
 476
 477    fn on_drag_move<T: 'static>(
 478        mut self,
 479        listener: impl Fn(&DragMoveEvent<T>, &mut WindowContext) + 'static,
 480    ) -> Self
 481    where
 482        T: 'static,
 483    {
 484        self.interactivity().on_drag_move(listener);
 485        self
 486    }
 487
 488    fn on_scroll_wheel(
 489        mut self,
 490        listener: impl Fn(&ScrollWheelEvent, &mut WindowContext) + 'static,
 491    ) -> Self {
 492        self.interactivity().on_scroll_wheel(listener);
 493        self
 494    }
 495
 496    /// Capture the given action, before normal action dispatch can fire
 497    fn capture_action<A: Action>(
 498        mut self,
 499        listener: impl Fn(&A, &mut WindowContext) + 'static,
 500    ) -> Self {
 501        self.interactivity().capture_action(listener);
 502        self
 503    }
 504
 505    /// Add a listener for the given action, fires during the bubble event phase
 506    fn on_action<A: Action>(mut self, listener: impl Fn(&A, &mut WindowContext) + 'static) -> Self {
 507        self.interactivity().on_action(listener);
 508        self
 509    }
 510
 511    fn on_boxed_action(
 512        mut self,
 513        action: &dyn Action,
 514        listener: impl Fn(&Box<dyn Action>, &mut WindowContext) + 'static,
 515    ) -> Self {
 516        self.interactivity().on_boxed_action(action, listener);
 517        self
 518    }
 519
 520    fn on_key_down(
 521        mut self,
 522        listener: impl Fn(&KeyDownEvent, &mut WindowContext) + 'static,
 523    ) -> Self {
 524        self.interactivity().on_key_down(listener);
 525        self
 526    }
 527
 528    fn capture_key_down(
 529        mut self,
 530        listener: impl Fn(&KeyDownEvent, &mut WindowContext) + 'static,
 531    ) -> Self {
 532        self.interactivity().capture_key_down(listener);
 533        self
 534    }
 535
 536    fn on_key_up(mut self, listener: impl Fn(&KeyUpEvent, &mut WindowContext) + 'static) -> Self {
 537        self.interactivity().on_key_up(listener);
 538        self
 539    }
 540
 541    fn capture_key_up(
 542        mut self,
 543        listener: impl Fn(&KeyUpEvent, &mut WindowContext) + 'static,
 544    ) -> Self {
 545        self.interactivity().capture_key_up(listener);
 546        self
 547    }
 548
 549    fn drag_over<S: 'static>(mut self, f: impl FnOnce(StyleRefinement) -> StyleRefinement) -> Self {
 550        self.interactivity()
 551            .drag_over_styles
 552            .push((TypeId::of::<S>(), f(StyleRefinement::default())));
 553        self
 554    }
 555
 556    fn group_drag_over<S: 'static>(
 557        mut self,
 558        group_name: impl Into<SharedString>,
 559        f: impl FnOnce(StyleRefinement) -> StyleRefinement,
 560    ) -> Self {
 561        self.interactivity().group_drag_over_styles.push((
 562            TypeId::of::<S>(),
 563            GroupStyle {
 564                group: group_name.into(),
 565                style: Box::new(f(StyleRefinement::default())),
 566            },
 567        ));
 568        self
 569    }
 570
 571    fn on_drop<T: 'static>(mut self, listener: impl Fn(&T, &mut WindowContext) + 'static) -> Self {
 572        self.interactivity().on_drop(listener);
 573        self
 574    }
 575
 576    fn can_drop(
 577        mut self,
 578        predicate: impl Fn(&dyn Any, &mut WindowContext) -> bool + 'static,
 579    ) -> Self {
 580        self.interactivity().can_drop(predicate);
 581        self
 582    }
 583
 584    fn block_mouse(mut self) -> Self {
 585        self.interactivity().block_mouse();
 586        self
 587    }
 588}
 589
 590pub trait StatefulInteractiveElement: InteractiveElement {
 591    fn focusable(mut self) -> Focusable<Self> {
 592        self.interactivity().focusable = true;
 593        Focusable { element: self }
 594    }
 595
 596    fn overflow_scroll(mut self) -> Self {
 597        self.interactivity().base_style.overflow.x = Some(Overflow::Scroll);
 598        self.interactivity().base_style.overflow.y = Some(Overflow::Scroll);
 599        self
 600    }
 601
 602    fn overflow_x_scroll(mut self) -> Self {
 603        self.interactivity().base_style.overflow.x = Some(Overflow::Scroll);
 604        self
 605    }
 606
 607    fn overflow_y_scroll(mut self) -> Self {
 608        self.interactivity().base_style.overflow.y = Some(Overflow::Scroll);
 609        self
 610    }
 611
 612    fn track_scroll(mut self, scroll_handle: &ScrollHandle) -> Self {
 613        self.interactivity().scroll_handle = Some(scroll_handle.clone());
 614        self
 615    }
 616
 617    fn active(mut self, f: impl FnOnce(StyleRefinement) -> StyleRefinement) -> Self
 618    where
 619        Self: Sized,
 620    {
 621        self.interactivity().active_style = Some(Box::new(f(StyleRefinement::default())));
 622        self
 623    }
 624
 625    fn group_active(
 626        mut self,
 627        group_name: impl Into<SharedString>,
 628        f: impl FnOnce(StyleRefinement) -> StyleRefinement,
 629    ) -> Self
 630    where
 631        Self: Sized,
 632    {
 633        self.interactivity().group_active_style = Some(GroupStyle {
 634            group: group_name.into(),
 635            style: Box::new(f(StyleRefinement::default())),
 636        });
 637        self
 638    }
 639
 640    fn on_click(mut self, listener: impl Fn(&ClickEvent, &mut WindowContext) + 'static) -> Self
 641    where
 642        Self: Sized,
 643    {
 644        self.interactivity().on_click(listener);
 645        self
 646    }
 647
 648    fn on_drag<T, W>(
 649        mut self,
 650        value: T,
 651        constructor: impl Fn(&T, &mut WindowContext) -> View<W> + 'static,
 652    ) -> Self
 653    where
 654        Self: Sized,
 655        T: 'static,
 656        W: 'static + Render,
 657    {
 658        self.interactivity().on_drag(value, constructor);
 659        self
 660    }
 661
 662    fn on_hover(mut self, listener: impl Fn(&bool, &mut WindowContext) + 'static) -> Self
 663    where
 664        Self: Sized,
 665    {
 666        self.interactivity().on_hover(listener);
 667        self
 668    }
 669
 670    fn tooltip(mut self, build_tooltip: impl Fn(&mut WindowContext) -> AnyView + 'static) -> Self
 671    where
 672        Self: Sized,
 673    {
 674        self.interactivity().tooltip(build_tooltip);
 675        self
 676    }
 677}
 678
 679pub trait FocusableElement: InteractiveElement {
 680    fn focus(mut self, f: impl FnOnce(StyleRefinement) -> StyleRefinement) -> Self
 681    where
 682        Self: Sized,
 683    {
 684        self.interactivity().focus_style = Some(Box::new(f(StyleRefinement::default())));
 685        self
 686    }
 687
 688    fn in_focus(mut self, f: impl FnOnce(StyleRefinement) -> StyleRefinement) -> Self
 689    where
 690        Self: Sized,
 691    {
 692        self.interactivity().in_focus_style = Some(Box::new(f(StyleRefinement::default())));
 693        self
 694    }
 695}
 696
 697pub type MouseDownListener =
 698    Box<dyn Fn(&MouseDownEvent, &InteractiveBounds, DispatchPhase, &mut WindowContext) + 'static>;
 699pub type MouseUpListener =
 700    Box<dyn Fn(&MouseUpEvent, &InteractiveBounds, DispatchPhase, &mut WindowContext) + 'static>;
 701
 702pub type MouseMoveListener =
 703    Box<dyn Fn(&MouseMoveEvent, &InteractiveBounds, DispatchPhase, &mut WindowContext) + 'static>;
 704
 705pub type ScrollWheelListener =
 706    Box<dyn Fn(&ScrollWheelEvent, &InteractiveBounds, DispatchPhase, &mut WindowContext) + 'static>;
 707
 708pub type ClickListener = Box<dyn Fn(&ClickEvent, &mut WindowContext) + 'static>;
 709
 710pub type DragListener = Box<dyn Fn(&dyn Any, &mut WindowContext) -> AnyView + 'static>;
 711
 712type DropListener = Box<dyn Fn(&dyn Any, &mut WindowContext) + 'static>;
 713
 714type CanDropPredicate = Box<dyn Fn(&dyn Any, &mut WindowContext) -> bool + 'static>;
 715
 716pub type TooltipBuilder = Rc<dyn Fn(&mut WindowContext) -> AnyView + 'static>;
 717
 718pub type KeyDownListener = Box<dyn Fn(&KeyDownEvent, DispatchPhase, &mut WindowContext) + 'static>;
 719
 720pub type KeyUpListener = Box<dyn Fn(&KeyUpEvent, DispatchPhase, &mut WindowContext) + 'static>;
 721
 722pub type DragEventListener = Box<dyn Fn(&MouseMoveEvent, &mut WindowContext) + 'static>;
 723
 724pub type ActionListener = Box<dyn Fn(&dyn Any, DispatchPhase, &mut WindowContext) + 'static>;
 725
 726#[track_caller]
 727pub fn div() -> Div {
 728    #[cfg(debug_assertions)]
 729    let interactivity = {
 730        let mut interactivity = Interactivity::default();
 731        interactivity.location = Some(*core::panic::Location::caller());
 732        interactivity
 733    };
 734
 735    #[cfg(not(debug_assertions))]
 736    let interactivity = Interactivity::default();
 737
 738    Div {
 739        interactivity,
 740        children: SmallVec::default(),
 741    }
 742}
 743
 744pub struct Div {
 745    interactivity: Interactivity,
 746    children: SmallVec<[AnyElement; 2]>,
 747}
 748
 749impl Styled for Div {
 750    fn style(&mut self) -> &mut StyleRefinement {
 751        &mut self.interactivity.base_style
 752    }
 753}
 754
 755impl InteractiveElement for Div {
 756    fn interactivity(&mut self) -> &mut Interactivity {
 757        &mut self.interactivity
 758    }
 759}
 760
 761impl ParentElement for Div {
 762    fn children_mut(&mut self) -> &mut SmallVec<[AnyElement; 2]> {
 763        &mut self.children
 764    }
 765}
 766
 767impl Element for Div {
 768    type State = DivState;
 769
 770    fn request_layout(
 771        &mut self,
 772        element_state: Option<Self::State>,
 773        cx: &mut WindowContext,
 774    ) -> (LayoutId, Self::State) {
 775        let mut child_layout_ids = SmallVec::new();
 776        let (layout_id, interactive_state) = self.interactivity.layout(
 777            element_state.map(|s| s.interactive_state),
 778            cx,
 779            |style, cx| {
 780                cx.with_text_style(style.text_style().cloned(), |cx| {
 781                    child_layout_ids = self
 782                        .children
 783                        .iter_mut()
 784                        .map(|child| child.request_layout(cx))
 785                        .collect::<SmallVec<_>>();
 786                    cx.request_layout(&style, child_layout_ids.iter().copied())
 787                })
 788            },
 789        );
 790        (
 791            layout_id,
 792            DivState {
 793                interactive_state,
 794                child_layout_ids,
 795            },
 796        )
 797    }
 798
 799    fn paint(
 800        &mut self,
 801        bounds: Bounds<Pixels>,
 802        element_state: &mut Self::State,
 803        cx: &mut WindowContext,
 804    ) {
 805        let mut child_min = point(Pixels::MAX, Pixels::MAX);
 806        let mut child_max = Point::default();
 807        let content_size = if element_state.child_layout_ids.is_empty() {
 808            bounds.size
 809        } else if let Some(scroll_handle) = self.interactivity.scroll_handle.as_ref() {
 810            let mut state = scroll_handle.0.borrow_mut();
 811            state.child_bounds = Vec::with_capacity(element_state.child_layout_ids.len());
 812            state.bounds = bounds;
 813            let requested = state.requested_scroll_top.take();
 814
 815            for (ix, child_layout_id) in element_state.child_layout_ids.iter().enumerate() {
 816                let child_bounds = cx.layout_bounds(*child_layout_id);
 817                child_min = child_min.min(&child_bounds.origin);
 818                child_max = child_max.max(&child_bounds.lower_right());
 819                state.child_bounds.push(child_bounds);
 820
 821                if let Some(requested) = requested.as_ref() {
 822                    if requested.0 == ix {
 823                        *state.offset.borrow_mut() =
 824                            bounds.origin - (child_bounds.origin - point(px(0.), requested.1));
 825                    }
 826                }
 827            }
 828            (child_max - child_min).into()
 829        } else {
 830            for child_layout_id in &element_state.child_layout_ids {
 831                let child_bounds = cx.layout_bounds(*child_layout_id);
 832                child_min = child_min.min(&child_bounds.origin);
 833                child_max = child_max.max(&child_bounds.lower_right());
 834            }
 835            (child_max - child_min).into()
 836        };
 837
 838        self.interactivity.paint(
 839            bounds,
 840            content_size,
 841            &mut element_state.interactive_state,
 842            cx,
 843            |_style, scroll_offset, cx| {
 844                cx.with_element_offset(scroll_offset, |cx| {
 845                    for child in &mut self.children {
 846                        child.paint(cx);
 847                    }
 848                })
 849            },
 850        );
 851    }
 852}
 853
 854impl IntoElement for Div {
 855    type Element = Self;
 856
 857    fn element_id(&self) -> Option<ElementId> {
 858        self.interactivity.element_id.clone()
 859    }
 860
 861    fn into_element(self) -> Self::Element {
 862        self
 863    }
 864}
 865
 866pub struct DivState {
 867    child_layout_ids: SmallVec<[LayoutId; 2]>,
 868    interactive_state: InteractiveElementState,
 869}
 870
 871impl DivState {
 872    pub fn is_active(&self) -> bool {
 873        self.interactive_state
 874            .pending_mouse_down
 875            .as_ref()
 876            .map_or(false, |pending| pending.borrow().is_some())
 877    }
 878}
 879
 880#[derive(Default)]
 881pub struct Interactivity {
 882    pub element_id: Option<ElementId>,
 883    pub key_context: Option<KeyContext>,
 884    pub focusable: bool,
 885    pub tracked_focus_handle: Option<FocusHandle>,
 886    pub scroll_handle: Option<ScrollHandle>,
 887    pub group: Option<SharedString>,
 888    pub base_style: Box<StyleRefinement>,
 889    pub focus_style: Option<Box<StyleRefinement>>,
 890    pub in_focus_style: Option<Box<StyleRefinement>>,
 891    pub hover_style: Option<Box<StyleRefinement>>,
 892    pub group_hover_style: Option<GroupStyle>,
 893    pub active_style: Option<Box<StyleRefinement>>,
 894    pub group_active_style: Option<GroupStyle>,
 895    pub drag_over_styles: Vec<(TypeId, StyleRefinement)>,
 896    pub group_drag_over_styles: Vec<(TypeId, GroupStyle)>,
 897    pub mouse_down_listeners: Vec<MouseDownListener>,
 898    pub mouse_up_listeners: Vec<MouseUpListener>,
 899    pub mouse_move_listeners: Vec<MouseMoveListener>,
 900    pub scroll_wheel_listeners: Vec<ScrollWheelListener>,
 901    pub key_down_listeners: Vec<KeyDownListener>,
 902    pub key_up_listeners: Vec<KeyUpListener>,
 903    pub action_listeners: Vec<(TypeId, ActionListener)>,
 904    pub drop_listeners: Vec<(TypeId, DropListener)>,
 905    pub can_drop_predicate: Option<CanDropPredicate>,
 906    pub click_listeners: Vec<ClickListener>,
 907    pub drag_listener: Option<(Box<dyn Any>, DragListener)>,
 908    pub hover_listener: Option<Box<dyn Fn(&bool, &mut WindowContext)>>,
 909    pub tooltip_builder: Option<TooltipBuilder>,
 910    pub block_mouse: bool,
 911
 912    #[cfg(debug_assertions)]
 913    pub location: Option<core::panic::Location<'static>>,
 914}
 915
 916#[derive(Clone, Debug)]
 917pub struct InteractiveBounds {
 918    pub bounds: Bounds<Pixels>,
 919    pub stacking_order: StackingOrder,
 920}
 921
 922impl InteractiveBounds {
 923    pub fn visibly_contains(&self, point: &Point<Pixels>, cx: &WindowContext) -> bool {
 924        self.bounds.contains(point) && cx.was_top_layer(point, &self.stacking_order)
 925    }
 926
 927    pub fn drag_target_contains(&self, point: &Point<Pixels>, cx: &WindowContext) -> bool {
 928        self.bounds.contains(point)
 929            && cx.was_top_layer_under_active_drag(point, &self.stacking_order)
 930    }
 931}
 932
 933impl Interactivity {
 934    pub fn layout(
 935        &mut self,
 936        element_state: Option<InteractiveElementState>,
 937        cx: &mut WindowContext,
 938        f: impl FnOnce(Style, &mut WindowContext) -> LayoutId,
 939    ) -> (LayoutId, InteractiveElementState) {
 940        let mut element_state = element_state.unwrap_or_default();
 941
 942        if cx.has_active_drag() {
 943            if let Some(pending_mouse_down) = element_state.pending_mouse_down.as_ref() {
 944                *pending_mouse_down.borrow_mut() = None;
 945            }
 946            if let Some(clicked_state) = element_state.clicked_state.as_ref() {
 947                *clicked_state.borrow_mut() = ElementClickedState::default();
 948            }
 949        }
 950
 951        // Ensure we store a focus handle in our element state if we're focusable.
 952        // If there's an explicit focus handle we're tracking, use that. Otherwise
 953        // create a new handle and store it in the element state, which lives for as
 954        // as frames contain an element with this id.
 955        if self.focusable {
 956            element_state.focus_handle.get_or_insert_with(|| {
 957                self.tracked_focus_handle
 958                    .clone()
 959                    .unwrap_or_else(|| cx.focus_handle())
 960            });
 961        }
 962
 963        if let Some(scroll_handle) = self.scroll_handle.as_ref() {
 964            element_state.scroll_offset = Some(scroll_handle.0.borrow().offset.clone());
 965        }
 966
 967        let style = self.compute_style(None, &mut element_state, cx);
 968        let layout_id = f(style, cx);
 969        (layout_id, element_state)
 970    }
 971
 972    pub fn paint(
 973        &mut self,
 974        bounds: Bounds<Pixels>,
 975        content_size: Size<Pixels>,
 976        element_state: &mut InteractiveElementState,
 977        cx: &mut WindowContext,
 978        f: impl FnOnce(&Style, Point<Pixels>, &mut WindowContext),
 979    ) {
 980        let style = self.compute_style(Some(bounds), element_state, cx);
 981
 982        if style.visibility == Visibility::Hidden {
 983            return;
 984        }
 985
 986        let z_index = style.z_index.unwrap_or(0);
 987        cx.with_z_index(z_index, |cx| {
 988            style.paint(bounds, cx, |cx| {
 989                cx.with_text_style(style.text_style().cloned(), |cx| {
 990                    cx.with_content_mask(style.overflow_mask(bounds, cx.rem_size()), |cx| {
 991                        #[cfg(debug_assertions)]
 992                        if self.element_id.is_some()
 993                            && (style.debug
 994                                || style.debug_below
 995                                || cx.has_global::<crate::DebugBelow>())
 996                            && bounds.contains(&cx.mouse_position())
 997                        {
 998                            const FONT_SIZE: crate::Pixels = crate::Pixels(10.);
 999                            let element_id = format!("{:?}", self.element_id.as_ref().unwrap());
1000                            let str_len = element_id.len();
1001
1002                            let render_debug_text = |cx: &mut WindowContext| {
1003                                if let Some(text) = cx
1004                                    .text_system()
1005                                    .shape_text(
1006                                        &element_id,
1007                                        FONT_SIZE,
1008                                        &[cx.text_style().to_run(str_len)],
1009                                        None,
1010                                    )
1011                                    .ok()
1012                                    .and_then(|mut text| text.pop())
1013                                {
1014                                    text.paint(bounds.origin, FONT_SIZE, cx).ok();
1015
1016                                    let text_bounds = crate::Bounds {
1017                                        origin: bounds.origin,
1018                                        size: text.size(FONT_SIZE),
1019                                    };
1020                                    if self.location.is_some()
1021                                        && text_bounds.contains(&cx.mouse_position())
1022                                        && cx.modifiers().command
1023                                    {
1024                                        let command_held = cx.modifiers().command;
1025                                        cx.on_key_event({
1026                                            move |e: &crate::ModifiersChangedEvent, _phase, cx| {
1027                                                if e.modifiers.command != command_held
1028                                                    && text_bounds.contains(&cx.mouse_position())
1029                                                {
1030                                                    cx.notify();
1031                                                }
1032                                            }
1033                                        });
1034
1035                                        let hovered = bounds.contains(&cx.mouse_position());
1036                                        cx.on_mouse_event(
1037                                            move |event: &MouseMoveEvent, phase, cx| {
1038                                                if phase == DispatchPhase::Capture
1039                                                    && bounds.contains(&event.position) != hovered
1040                                                {
1041                                                    cx.notify();
1042                                                }
1043                                            },
1044                                        );
1045
1046                                        cx.on_mouse_event({
1047                                            let location = self.location.unwrap();
1048                                            move |e: &crate::MouseDownEvent, phase, cx| {
1049                                                if text_bounds.contains(&e.position)
1050                                                    && phase.capture()
1051                                                {
1052                                                    cx.stop_propagation();
1053                                                    let Ok(dir) = std::env::current_dir() else {
1054                                                        return;
1055                                                    };
1056
1057                                                    eprintln!(
1058                                                        "This element is created at:\n{}:{}:{}",
1059                                                        location.file(),
1060                                                        location.line(),
1061                                                        location.column()
1062                                                    );
1063
1064                                                    std::process::Command::new("zed")
1065                                                        .arg(format!(
1066                                                            "{}/{}:{}:{}",
1067                                                            dir.to_string_lossy(),
1068                                                            location.file(),
1069                                                            location.line(),
1070                                                            location.column()
1071                                                        ))
1072                                                        .spawn()
1073                                                        .ok();
1074                                                }
1075                                            }
1076                                        });
1077                                        cx.paint_quad(crate::outline(
1078                                            crate::Bounds {
1079                                                origin: bounds.origin
1080                                                    + crate::point(
1081                                                        crate::px(0.),
1082                                                        FONT_SIZE - px(2.),
1083                                                    ),
1084                                                size: crate::Size {
1085                                                    width: text_bounds.size.width,
1086                                                    height: crate::px(1.),
1087                                                },
1088                                            },
1089                                            crate::red(),
1090                                        ))
1091                                    }
1092                                }
1093                            };
1094
1095                            cx.with_z_index(1, |cx| {
1096                                cx.with_text_style(
1097                                    Some(crate::TextStyleRefinement {
1098                                        color: Some(crate::red()),
1099                                        line_height: Some(FONT_SIZE.into()),
1100                                        background_color: Some(crate::white()),
1101                                        ..Default::default()
1102                                    }),
1103                                    render_debug_text,
1104                                )
1105                            });
1106                        }
1107
1108                        let interactive_bounds = InteractiveBounds {
1109                            bounds: bounds.intersect(&cx.content_mask().bounds),
1110                            stacking_order: cx.stacking_order().clone(),
1111                        };
1112
1113                        if self.block_mouse
1114                            || style.background.as_ref().is_some_and(|fill| {
1115                                fill.color().is_some_and(|color| !color.is_transparent())
1116                            })
1117                        {
1118                            cx.add_opaque_layer(interactive_bounds.bounds);
1119                        }
1120
1121                        if !cx.has_active_drag() {
1122                            if let Some(mouse_cursor) = style.mouse_cursor {
1123                                let mouse_position = &cx.mouse_position();
1124                                let hovered =
1125                                    interactive_bounds.visibly_contains(mouse_position, cx);
1126                                if hovered {
1127                                    cx.set_cursor_style(mouse_cursor);
1128                                }
1129                            }
1130                        }
1131
1132                        // If this element can be focused, register a mouse down listener
1133                        // that will automatically transfer focus when hitting the element.
1134                        // This behavior can be suppressed by using `cx.prevent_default()`.
1135                        if let Some(focus_handle) = element_state.focus_handle.clone() {
1136                            cx.on_mouse_event({
1137                                let interactive_bounds = interactive_bounds.clone();
1138                                move |event: &MouseDownEvent, phase, cx| {
1139                                    if phase == DispatchPhase::Bubble
1140                                        && !cx.default_prevented()
1141                                        && interactive_bounds.visibly_contains(&event.position, cx)
1142                                    {
1143                                        cx.focus(&focus_handle);
1144                                        // If there is a parent that is also focusable, prevent it
1145                                        // from transferring focus because we already did so.
1146                                        cx.prevent_default();
1147                                    }
1148                                }
1149                            });
1150                        }
1151
1152                        for listener in self.mouse_down_listeners.drain(..) {
1153                            let interactive_bounds = interactive_bounds.clone();
1154                            cx.on_mouse_event(move |event: &MouseDownEvent, phase, cx| {
1155                                listener(event, &interactive_bounds, phase, cx);
1156                            })
1157                        }
1158
1159                        for listener in self.mouse_up_listeners.drain(..) {
1160                            let interactive_bounds = interactive_bounds.clone();
1161                            cx.on_mouse_event(move |event: &MouseUpEvent, phase, cx| {
1162                                listener(event, &interactive_bounds, phase, cx);
1163                            })
1164                        }
1165
1166                        for listener in self.mouse_move_listeners.drain(..) {
1167                            let interactive_bounds = interactive_bounds.clone();
1168                            cx.on_mouse_event(move |event: &MouseMoveEvent, phase, cx| {
1169                                listener(event, &interactive_bounds, phase, cx);
1170                            })
1171                        }
1172
1173                        for listener in self.scroll_wheel_listeners.drain(..) {
1174                            let interactive_bounds = interactive_bounds.clone();
1175                            cx.on_mouse_event(move |event: &ScrollWheelEvent, phase, cx| {
1176                                listener(event, &interactive_bounds, phase, cx);
1177                            })
1178                        }
1179
1180                        let hover_group_bounds = self
1181                            .group_hover_style
1182                            .as_ref()
1183                            .and_then(|group_hover| GroupBounds::get(&group_hover.group, cx));
1184
1185                        if let Some(group_bounds) = hover_group_bounds {
1186                            let hovered = group_bounds.contains(&cx.mouse_position());
1187                            cx.on_mouse_event(move |event: &MouseMoveEvent, phase, cx| {
1188                                if phase == DispatchPhase::Capture
1189                                    && group_bounds.contains(&event.position) != hovered
1190                                {
1191                                    cx.notify();
1192                                }
1193                            });
1194                        }
1195
1196                        if self.hover_style.is_some()
1197                            || self.base_style.mouse_cursor.is_some()
1198                            || cx.active_drag.is_some() && !self.drag_over_styles.is_empty()
1199                        {
1200                            let bounds = bounds.intersect(&cx.content_mask().bounds);
1201                            let hovered = bounds.contains(&cx.mouse_position());
1202                            cx.on_mouse_event(move |event: &MouseMoveEvent, phase, cx| {
1203                                if phase == DispatchPhase::Capture
1204                                    && bounds.contains(&event.position) != hovered
1205                                {
1206                                    cx.notify();
1207                                }
1208                            });
1209                        }
1210
1211                        let mut drag_listener = mem::take(&mut self.drag_listener);
1212                        let drop_listeners = mem::take(&mut self.drop_listeners);
1213                        let click_listeners = mem::take(&mut self.click_listeners);
1214                        let can_drop_predicate = mem::take(&mut self.can_drop_predicate);
1215
1216                        if !drop_listeners.is_empty() {
1217                            cx.on_mouse_event({
1218                                let interactive_bounds = interactive_bounds.clone();
1219                                move |event: &MouseUpEvent, phase, cx| {
1220                                    if let Some(drag) = &cx.active_drag {
1221                                        if phase == DispatchPhase::Bubble
1222                                            && interactive_bounds
1223                                                .drag_target_contains(&event.position, cx)
1224                                        {
1225                                            let drag_state_type = drag.value.as_ref().type_id();
1226                                            for (drop_state_type, listener) in &drop_listeners {
1227                                                if *drop_state_type == drag_state_type {
1228                                                    let drag = cx.active_drag.take().expect(
1229                                                        "checked for type drag state type above",
1230                                                    );
1231
1232                                                    let mut can_drop = true;
1233                                                    if let Some(predicate) = &can_drop_predicate {
1234                                                        can_drop =
1235                                                            predicate(drag.value.as_ref(), cx);
1236                                                    }
1237
1238                                                    if can_drop {
1239                                                        listener(drag.value.as_ref(), cx);
1240                                                        cx.notify();
1241                                                        cx.stop_propagation();
1242                                                    }
1243                                                }
1244                                            }
1245                                        }
1246                                    }
1247                                }
1248                            });
1249                        }
1250
1251                        if !click_listeners.is_empty() || drag_listener.is_some() {
1252                            let pending_mouse_down = element_state
1253                                .pending_mouse_down
1254                                .get_or_insert_with(Default::default)
1255                                .clone();
1256
1257                            let clicked_state = element_state
1258                                .clicked_state
1259                                .get_or_insert_with(Default::default)
1260                                .clone();
1261
1262                            cx.on_mouse_event({
1263                                let interactive_bounds = interactive_bounds.clone();
1264                                let pending_mouse_down = pending_mouse_down.clone();
1265                                move |event: &MouseDownEvent, phase, cx| {
1266                                    if phase == DispatchPhase::Bubble
1267                                        && event.button == MouseButton::Left
1268                                        && interactive_bounds.visibly_contains(&event.position, cx)
1269                                    {
1270                                        *pending_mouse_down.borrow_mut() = Some(event.clone());
1271                                        cx.notify();
1272                                    }
1273                                }
1274                            });
1275
1276                            cx.on_mouse_event({
1277                                let pending_mouse_down = pending_mouse_down.clone();
1278                                move |event: &MouseMoveEvent, phase, cx| {
1279                                    if phase == DispatchPhase::Capture {
1280                                        return;
1281                                    }
1282
1283                                    let mut pending_mouse_down = pending_mouse_down.borrow_mut();
1284                                    if let Some(mouse_down) = pending_mouse_down.clone() {
1285                                        if !cx.has_active_drag()
1286                                            && (event.position - mouse_down.position).magnitude()
1287                                                > DRAG_THRESHOLD
1288                                        {
1289                                            if let Some((drag_value, drag_listener)) =
1290                                                drag_listener.take()
1291                                            {
1292                                                *clicked_state.borrow_mut() =
1293                                                    ElementClickedState::default();
1294                                                let cursor_offset = event.position - bounds.origin;
1295                                                let drag = (drag_listener)(drag_value.as_ref(), cx);
1296                                                cx.active_drag = Some(AnyDrag {
1297                                                    view: drag,
1298                                                    value: drag_value,
1299                                                    cursor_offset,
1300                                                });
1301                                                pending_mouse_down.take();
1302                                                cx.notify();
1303                                                cx.stop_propagation();
1304                                            }
1305                                        }
1306                                    }
1307                                }
1308                            });
1309
1310                            cx.on_mouse_event({
1311                                let interactive_bounds = interactive_bounds.clone();
1312                                let mut captured_mouse_down = None;
1313                                move |event: &MouseUpEvent, phase, cx| match phase {
1314                                    // Clear the pending mouse down during the capture phase,
1315                                    // so that it happens even if another event handler stops
1316                                    // propagation.
1317                                    DispatchPhase::Capture => {
1318                                        let mut pending_mouse_down =
1319                                            pending_mouse_down.borrow_mut();
1320                                        if pending_mouse_down.is_some() {
1321                                            captured_mouse_down = pending_mouse_down.take();
1322                                            cx.notify();
1323                                        }
1324                                    }
1325                                    // Fire click handlers during the bubble phase.
1326                                    DispatchPhase::Bubble => {
1327                                        if let Some(mouse_down) = captured_mouse_down.take() {
1328                                            if interactive_bounds
1329                                                .visibly_contains(&event.position, cx)
1330                                            {
1331                                                let mouse_click = ClickEvent {
1332                                                    down: mouse_down,
1333                                                    up: event.clone(),
1334                                                };
1335                                                for listener in &click_listeners {
1336                                                    listener(&mouse_click, cx);
1337                                                }
1338                                            }
1339                                        }
1340                                    }
1341                                }
1342                            });
1343                        }
1344
1345                        if let Some(hover_listener) = self.hover_listener.take() {
1346                            let was_hovered = element_state
1347                                .hover_state
1348                                .get_or_insert_with(Default::default)
1349                                .clone();
1350                            let has_mouse_down = element_state
1351                                .pending_mouse_down
1352                                .get_or_insert_with(Default::default)
1353                                .clone();
1354                            let interactive_bounds = interactive_bounds.clone();
1355
1356                            cx.on_mouse_event(move |event: &MouseMoveEvent, phase, cx| {
1357                                if phase != DispatchPhase::Bubble {
1358                                    return;
1359                                }
1360                                let is_hovered = interactive_bounds
1361                                    .visibly_contains(&event.position, cx)
1362                                    && has_mouse_down.borrow().is_none()
1363                                    && !cx.has_active_drag();
1364                                let mut was_hovered = was_hovered.borrow_mut();
1365
1366                                if is_hovered != *was_hovered {
1367                                    *was_hovered = is_hovered;
1368                                    drop(was_hovered);
1369
1370                                    hover_listener(&is_hovered, cx);
1371                                }
1372                            });
1373                        }
1374
1375                        if let Some(tooltip_builder) = self.tooltip_builder.take() {
1376                            let active_tooltip = element_state
1377                                .active_tooltip
1378                                .get_or_insert_with(Default::default)
1379                                .clone();
1380                            let pending_mouse_down = element_state
1381                                .pending_mouse_down
1382                                .get_or_insert_with(Default::default)
1383                                .clone();
1384                            let interactive_bounds = interactive_bounds.clone();
1385
1386                            cx.on_mouse_event(move |event: &MouseMoveEvent, phase, cx| {
1387                                let is_hovered = interactive_bounds
1388                                    .visibly_contains(&event.position, cx)
1389                                    && pending_mouse_down.borrow().is_none();
1390                                if !is_hovered {
1391                                    active_tooltip.borrow_mut().take();
1392                                    return;
1393                                }
1394
1395                                if phase != DispatchPhase::Bubble {
1396                                    return;
1397                                }
1398
1399                                if active_tooltip.borrow().is_none() {
1400                                    let task = cx.spawn({
1401                                        let active_tooltip = active_tooltip.clone();
1402                                        let tooltip_builder = tooltip_builder.clone();
1403
1404                                        move |mut cx| async move {
1405                                            cx.background_executor().timer(TOOLTIP_DELAY).await;
1406                                            cx.update(|_, cx| {
1407                                                active_tooltip.borrow_mut().replace(
1408                                                    ActiveTooltip {
1409                                                        tooltip: Some(AnyTooltip {
1410                                                            view: tooltip_builder(cx),
1411                                                            cursor_offset: cx.mouse_position(),
1412                                                        }),
1413                                                        _task: None,
1414                                                    },
1415                                                );
1416                                                cx.notify();
1417                                            })
1418                                            .ok();
1419                                        }
1420                                    });
1421                                    active_tooltip.borrow_mut().replace(ActiveTooltip {
1422                                        tooltip: None,
1423                                        _task: Some(task),
1424                                    });
1425                                }
1426                            });
1427
1428                            let active_tooltip = element_state
1429                                .active_tooltip
1430                                .get_or_insert_with(Default::default)
1431                                .clone();
1432                            cx.on_mouse_event(move |_: &MouseDownEvent, _, _| {
1433                                active_tooltip.borrow_mut().take();
1434                            });
1435
1436                            if let Some(active_tooltip) = element_state
1437                                .active_tooltip
1438                                .get_or_insert_with(Default::default)
1439                                .borrow()
1440                                .as_ref()
1441                            {
1442                                if active_tooltip.tooltip.is_some() {
1443                                    cx.active_tooltip = active_tooltip.tooltip.clone()
1444                                }
1445                            }
1446                        }
1447
1448                        let active_state = element_state
1449                            .clicked_state
1450                            .get_or_insert_with(Default::default)
1451                            .clone();
1452                        if active_state.borrow().is_clicked() {
1453                            cx.on_mouse_event(move |_: &MouseUpEvent, phase, cx| {
1454                                if phase == DispatchPhase::Capture {
1455                                    *active_state.borrow_mut() = ElementClickedState::default();
1456                                    cx.notify();
1457                                }
1458                            });
1459                        } else {
1460                            let active_group_bounds = self
1461                                .group_active_style
1462                                .as_ref()
1463                                .and_then(|group_active| GroupBounds::get(&group_active.group, cx));
1464                            let interactive_bounds = interactive_bounds.clone();
1465                            cx.on_mouse_event(move |down: &MouseDownEvent, phase, cx| {
1466                                if phase == DispatchPhase::Bubble && !cx.default_prevented() {
1467                                    let group = active_group_bounds
1468                                        .map_or(false, |bounds| bounds.contains(&down.position));
1469                                    let element =
1470                                        interactive_bounds.visibly_contains(&down.position, cx);
1471                                    if group || element {
1472                                        *active_state.borrow_mut() =
1473                                            ElementClickedState { group, element };
1474                                        cx.notify();
1475                                    }
1476                                }
1477                            });
1478                        }
1479
1480                        let overflow = style.overflow;
1481                        if overflow.x == Overflow::Scroll || overflow.y == Overflow::Scroll {
1482                            if let Some(scroll_handle) = &self.scroll_handle {
1483                                scroll_handle.0.borrow_mut().overflow = overflow;
1484                            }
1485
1486                            let scroll_offset = element_state
1487                                .scroll_offset
1488                                .get_or_insert_with(Rc::default)
1489                                .clone();
1490                            let line_height = cx.line_height();
1491                            let scroll_max = (content_size - bounds.size).max(&Size::default());
1492                            // Clamp scroll offset in case scroll max is smaller now (e.g., if children
1493                            // were removed or the bounds became larger).
1494                            {
1495                                let mut scroll_offset = scroll_offset.borrow_mut();
1496                                scroll_offset.x = scroll_offset.x.clamp(-scroll_max.width, px(0.));
1497                                scroll_offset.y = scroll_offset.y.clamp(-scroll_max.height, px(0.));
1498                            }
1499
1500                            let interactive_bounds = interactive_bounds.clone();
1501                            cx.on_mouse_event(move |event: &ScrollWheelEvent, phase, cx| {
1502                                if phase == DispatchPhase::Bubble
1503                                    && interactive_bounds.visibly_contains(&event.position, cx)
1504                                {
1505                                    let mut scroll_offset = scroll_offset.borrow_mut();
1506                                    let old_scroll_offset = *scroll_offset;
1507                                    let delta = event.delta.pixel_delta(line_height);
1508
1509                                    if overflow.x == Overflow::Scroll {
1510                                        let mut delta_x = Pixels::ZERO;
1511                                        if !delta.x.is_zero() {
1512                                            delta_x = delta.x;
1513                                        } else if overflow.y != Overflow::Scroll {
1514                                            delta_x = delta.y;
1515                                        }
1516
1517                                        scroll_offset.x = (scroll_offset.x + delta_x)
1518                                            .clamp(-scroll_max.width, px(0.));
1519                                    }
1520
1521                                    if overflow.y == Overflow::Scroll {
1522                                        let mut delta_y = Pixels::ZERO;
1523                                        if !delta.y.is_zero() {
1524                                            delta_y = delta.y;
1525                                        } else if overflow.x != Overflow::Scroll {
1526                                            delta_y = delta.x;
1527                                        }
1528
1529                                        scroll_offset.y = (scroll_offset.y + delta_y)
1530                                            .clamp(-scroll_max.height, px(0.));
1531                                    }
1532
1533                                    if *scroll_offset != old_scroll_offset {
1534                                        cx.notify();
1535                                        cx.stop_propagation();
1536                                    }
1537                                }
1538                            });
1539                        }
1540
1541                        if let Some(group) = self.group.clone() {
1542                            GroupBounds::push(group, bounds, cx);
1543                        }
1544
1545                        let scroll_offset = element_state
1546                            .scroll_offset
1547                            .as_ref()
1548                            .map(|scroll_offset| *scroll_offset.borrow());
1549
1550                        let key_down_listeners = mem::take(&mut self.key_down_listeners);
1551                        let key_up_listeners = mem::take(&mut self.key_up_listeners);
1552                        let action_listeners = mem::take(&mut self.action_listeners);
1553                        cx.with_key_dispatch(
1554                            self.key_context.clone(),
1555                            element_state.focus_handle.clone(),
1556                            |_, cx| {
1557                                for listener in key_down_listeners {
1558                                    cx.on_key_event(move |event: &KeyDownEvent, phase, cx| {
1559                                        listener(event, phase, cx);
1560                                    })
1561                                }
1562
1563                                for listener in key_up_listeners {
1564                                    cx.on_key_event(move |event: &KeyUpEvent, phase, cx| {
1565                                        listener(event, phase, cx);
1566                                    })
1567                                }
1568
1569                                for (action_type, listener) in action_listeners {
1570                                    cx.on_action(action_type, listener)
1571                                }
1572
1573                                f(&style, scroll_offset.unwrap_or_default(), cx)
1574                            },
1575                        );
1576
1577                        if let Some(group) = self.group.as_ref() {
1578                            GroupBounds::pop(group, cx);
1579                        }
1580                    });
1581                });
1582            });
1583        });
1584    }
1585
1586    pub fn compute_style(
1587        &self,
1588        bounds: Option<Bounds<Pixels>>,
1589        element_state: &mut InteractiveElementState,
1590        cx: &mut WindowContext,
1591    ) -> Style {
1592        let mut style = Style::default();
1593        style.refine(&self.base_style);
1594
1595        cx.with_z_index(style.z_index.unwrap_or(0), |cx| {
1596            if let Some(focus_handle) = self.tracked_focus_handle.as_ref() {
1597                if let Some(in_focus_style) = self.in_focus_style.as_ref() {
1598                    if focus_handle.within_focused(cx) {
1599                        style.refine(in_focus_style);
1600                    }
1601                }
1602
1603                if let Some(focus_style) = self.focus_style.as_ref() {
1604                    if focus_handle.is_focused(cx) {
1605                        style.refine(focus_style);
1606                    }
1607                }
1608            }
1609
1610            if let Some(bounds) = bounds {
1611                let mouse_position = cx.mouse_position();
1612                if !cx.has_active_drag() {
1613                    if let Some(group_hover) = self.group_hover_style.as_ref() {
1614                        if let Some(group_bounds) = GroupBounds::get(&group_hover.group, cx) {
1615                            if group_bounds.contains(&mouse_position)
1616                                && cx.was_top_layer(&mouse_position, cx.stacking_order())
1617                            {
1618                                style.refine(&group_hover.style);
1619                            }
1620                        }
1621                    }
1622
1623                    if let Some(hover_style) = self.hover_style.as_ref() {
1624                        if bounds
1625                            .intersect(&cx.content_mask().bounds)
1626                            .contains(&mouse_position)
1627                            && cx.was_top_layer(&mouse_position, cx.stacking_order())
1628                        {
1629                            style.refine(hover_style);
1630                        }
1631                    }
1632                }
1633
1634                if let Some(drag) = cx.active_drag.take() {
1635                    let mut can_drop = true;
1636                    if let Some(can_drop_predicate) = &self.can_drop_predicate {
1637                        can_drop = can_drop_predicate(drag.value.as_ref(), cx);
1638                    }
1639
1640                    if can_drop {
1641                        for (state_type, group_drag_style) in &self.group_drag_over_styles {
1642                            if let Some(group_bounds) =
1643                                GroupBounds::get(&group_drag_style.group, cx)
1644                            {
1645                                if *state_type == drag.value.as_ref().type_id()
1646                                    && group_bounds.contains(&mouse_position)
1647                                {
1648                                    style.refine(&group_drag_style.style);
1649                                }
1650                            }
1651                        }
1652
1653                        for (state_type, drag_over_style) in &self.drag_over_styles {
1654                            if *state_type == drag.value.as_ref().type_id()
1655                                && bounds
1656                                    .intersect(&cx.content_mask().bounds)
1657                                    .contains(&mouse_position)
1658                                && cx.was_top_layer_under_active_drag(
1659                                    &mouse_position,
1660                                    cx.stacking_order(),
1661                                )
1662                            {
1663                                style.refine(drag_over_style);
1664                            }
1665                        }
1666                    }
1667
1668                    cx.active_drag = Some(drag);
1669                }
1670            }
1671
1672            let clicked_state = element_state
1673                .clicked_state
1674                .get_or_insert_with(Default::default)
1675                .borrow();
1676            if clicked_state.group {
1677                if let Some(group) = self.group_active_style.as_ref() {
1678                    style.refine(&group.style)
1679                }
1680            }
1681
1682            if let Some(active_style) = self.active_style.as_ref() {
1683                if clicked_state.element {
1684                    style.refine(active_style)
1685                }
1686            }
1687        });
1688
1689        style
1690    }
1691}
1692
1693#[derive(Default)]
1694pub struct InteractiveElementState {
1695    pub focus_handle: Option<FocusHandle>,
1696    pub clicked_state: Option<Rc<RefCell<ElementClickedState>>>,
1697    pub hover_state: Option<Rc<RefCell<bool>>>,
1698    pub pending_mouse_down: Option<Rc<RefCell<Option<MouseDownEvent>>>>,
1699    pub scroll_offset: Option<Rc<RefCell<Point<Pixels>>>>,
1700    pub active_tooltip: Option<Rc<RefCell<Option<ActiveTooltip>>>>,
1701}
1702
1703pub struct ActiveTooltip {
1704    tooltip: Option<AnyTooltip>,
1705    _task: Option<Task<()>>,
1706}
1707
1708/// Whether or not the element or a group that contains it is clicked by the mouse.
1709#[derive(Copy, Clone, Default, Eq, PartialEq)]
1710pub struct ElementClickedState {
1711    pub group: bool,
1712    pub element: bool,
1713}
1714
1715impl ElementClickedState {
1716    fn is_clicked(&self) -> bool {
1717        self.group || self.element
1718    }
1719}
1720
1721#[derive(Default)]
1722pub struct GroupBounds(HashMap<SharedString, SmallVec<[Bounds<Pixels>; 1]>>);
1723
1724impl GroupBounds {
1725    pub fn get(name: &SharedString, cx: &mut AppContext) -> Option<Bounds<Pixels>> {
1726        cx.default_global::<Self>()
1727            .0
1728            .get(name)
1729            .and_then(|bounds_stack| bounds_stack.last())
1730            .cloned()
1731    }
1732
1733    pub fn push(name: SharedString, bounds: Bounds<Pixels>, cx: &mut AppContext) {
1734        cx.default_global::<Self>()
1735            .0
1736            .entry(name)
1737            .or_default()
1738            .push(bounds);
1739    }
1740
1741    pub fn pop(name: &SharedString, cx: &mut AppContext) {
1742        cx.default_global::<Self>().0.get_mut(name).unwrap().pop();
1743    }
1744}
1745
1746pub struct Focusable<E> {
1747    pub element: E,
1748}
1749
1750impl<E: InteractiveElement> FocusableElement for Focusable<E> {}
1751
1752impl<E> InteractiveElement for Focusable<E>
1753where
1754    E: InteractiveElement,
1755{
1756    fn interactivity(&mut self) -> &mut Interactivity {
1757        self.element.interactivity()
1758    }
1759}
1760
1761impl<E: StatefulInteractiveElement> StatefulInteractiveElement for Focusable<E> {}
1762
1763impl<E> Styled for Focusable<E>
1764where
1765    E: Styled,
1766{
1767    fn style(&mut self) -> &mut StyleRefinement {
1768        self.element.style()
1769    }
1770}
1771
1772impl<E> Element for Focusable<E>
1773where
1774    E: Element,
1775{
1776    type State = E::State;
1777
1778    fn request_layout(
1779        &mut self,
1780        state: Option<Self::State>,
1781        cx: &mut WindowContext,
1782    ) -> (LayoutId, Self::State) {
1783        self.element.request_layout(state, cx)
1784    }
1785
1786    fn paint(&mut self, bounds: Bounds<Pixels>, state: &mut Self::State, cx: &mut WindowContext) {
1787        self.element.paint(bounds, state, cx)
1788    }
1789}
1790
1791impl<E> IntoElement for Focusable<E>
1792where
1793    E: IntoElement,
1794{
1795    type Element = E::Element;
1796
1797    fn element_id(&self) -> Option<ElementId> {
1798        self.element.element_id()
1799    }
1800
1801    fn into_element(self) -> Self::Element {
1802        self.element.into_element()
1803    }
1804}
1805
1806impl<E> ParentElement for Focusable<E>
1807where
1808    E: ParentElement,
1809{
1810    fn children_mut(&mut self) -> &mut SmallVec<[AnyElement; 2]> {
1811        self.element.children_mut()
1812    }
1813}
1814
1815pub struct Stateful<E> {
1816    element: E,
1817}
1818
1819impl<E> Styled for Stateful<E>
1820where
1821    E: Styled,
1822{
1823    fn style(&mut self) -> &mut StyleRefinement {
1824        self.element.style()
1825    }
1826}
1827
1828impl<E> StatefulInteractiveElement for Stateful<E>
1829where
1830    E: Element,
1831    Self: InteractiveElement,
1832{
1833}
1834
1835impl<E> InteractiveElement for Stateful<E>
1836where
1837    E: InteractiveElement,
1838{
1839    fn interactivity(&mut self) -> &mut Interactivity {
1840        self.element.interactivity()
1841    }
1842}
1843
1844impl<E: FocusableElement> FocusableElement for Stateful<E> {}
1845
1846impl<E> Element for Stateful<E>
1847where
1848    E: Element,
1849{
1850    type State = E::State;
1851
1852    fn request_layout(
1853        &mut self,
1854        state: Option<Self::State>,
1855        cx: &mut WindowContext,
1856    ) -> (LayoutId, Self::State) {
1857        self.element.request_layout(state, cx)
1858    }
1859
1860    fn paint(&mut self, bounds: Bounds<Pixels>, state: &mut Self::State, cx: &mut WindowContext) {
1861        self.element.paint(bounds, state, cx)
1862    }
1863}
1864
1865impl<E> IntoElement for Stateful<E>
1866where
1867    E: Element,
1868{
1869    type Element = Self;
1870
1871    fn element_id(&self) -> Option<ElementId> {
1872        self.element.element_id()
1873    }
1874
1875    fn into_element(self) -> Self::Element {
1876        self
1877    }
1878}
1879
1880impl<E> ParentElement for Stateful<E>
1881where
1882    E: ParentElement,
1883{
1884    fn children_mut(&mut self) -> &mut SmallVec<[AnyElement; 2]> {
1885        self.element.children_mut()
1886    }
1887}
1888
1889#[derive(Default)]
1890struct ScrollHandleState {
1891    // not great to have the nested rc's...
1892    offset: Rc<RefCell<Point<Pixels>>>,
1893    bounds: Bounds<Pixels>,
1894    child_bounds: Vec<Bounds<Pixels>>,
1895    requested_scroll_top: Option<(usize, Pixels)>,
1896    overflow: Point<Overflow>,
1897}
1898
1899#[derive(Clone)]
1900pub struct ScrollHandle(Rc<RefCell<ScrollHandleState>>);
1901
1902impl Default for ScrollHandle {
1903    fn default() -> Self {
1904        Self::new()
1905    }
1906}
1907
1908impl ScrollHandle {
1909    pub fn new() -> Self {
1910        Self(Rc::default())
1911    }
1912
1913    pub fn offset(&self) -> Point<Pixels> {
1914        *self.0.borrow().offset.borrow()
1915    }
1916
1917    pub fn top_item(&self) -> usize {
1918        let state = self.0.borrow();
1919        let top = state.bounds.top() - state.offset.borrow().y;
1920
1921        match state.child_bounds.binary_search_by(|bounds| {
1922            if top < bounds.top() {
1923                Ordering::Greater
1924            } else if top > bounds.bottom() {
1925                Ordering::Less
1926            } else {
1927                Ordering::Equal
1928            }
1929        }) {
1930            Ok(ix) => ix,
1931            Err(ix) => ix.min(state.child_bounds.len().saturating_sub(1)),
1932        }
1933    }
1934
1935    pub fn bounds_for_item(&self, ix: usize) -> Option<Bounds<Pixels>> {
1936        self.0.borrow().child_bounds.get(ix).cloned()
1937    }
1938
1939    /// scroll_to_item scrolls the minimal amount to ensure that the item is
1940    /// fully visible
1941    pub fn scroll_to_item(&self, ix: usize) {
1942        let state = self.0.borrow();
1943
1944        let Some(bounds) = state.child_bounds.get(ix) else {
1945            return;
1946        };
1947
1948        let mut scroll_offset = state.offset.borrow_mut();
1949
1950        if state.overflow.y == Overflow::Scroll {
1951            if bounds.top() + scroll_offset.y < state.bounds.top() {
1952                scroll_offset.y = state.bounds.top() - bounds.top();
1953            } else if bounds.bottom() + scroll_offset.y > state.bounds.bottom() {
1954                scroll_offset.y = state.bounds.bottom() - bounds.bottom();
1955            }
1956        }
1957
1958        if state.overflow.x == Overflow::Scroll {
1959            if bounds.left() + scroll_offset.x < state.bounds.left() {
1960                scroll_offset.x = state.bounds.left() - bounds.left();
1961            } else if bounds.right() + scroll_offset.x > state.bounds.right() {
1962                scroll_offset.x = state.bounds.right() - bounds.right();
1963            }
1964        }
1965    }
1966
1967    pub fn logical_scroll_top(&self) -> (usize, Pixels) {
1968        let ix = self.top_item();
1969        let state = self.0.borrow();
1970
1971        if let Some(child_bounds) = state.child_bounds.get(ix) {
1972            (
1973                ix,
1974                child_bounds.top() + state.offset.borrow().y - state.bounds.top(),
1975            )
1976        } else {
1977            (ix, px(0.))
1978        }
1979    }
1980
1981    pub fn set_logical_scroll_top(&self, ix: usize, px: Pixels) {
1982        self.0.borrow_mut().requested_scroll_top = Some((ix, px));
1983    }
1984}