node.rs

   1use crate::{
   2    point, px, Action, AnyDrag, AnyElement, AnyTooltip, AnyView, AppContext, BorrowAppContext,
   3    BorrowWindow, Bounds, ClickEvent, DispatchPhase, Element, FocusHandle, KeyContext,
   4    KeyDownEvent, KeyUpEvent, LayoutId, MouseButton, MouseDownEvent, MouseMoveEvent, MouseUpEvent,
   5    Pixels, Point, Render, ScrollWheelEvent, SharedString, Size, Style, StyleRefinement, Styled,
   6    Task, View, ViewContext, Visibility,
   7};
   8use collections::HashMap;
   9use parking_lot::Mutex;
  10use refineable::Refineable;
  11use smallvec::SmallVec;
  12use std::{
  13    any::{Any, TypeId},
  14    marker::PhantomData,
  15    mem,
  16    sync::Arc,
  17    time::Duration,
  18};
  19use taffy::style::Overflow;
  20
  21const DRAG_THRESHOLD: f64 = 2.;
  22const TOOLTIP_DELAY: Duration = Duration::from_millis(500);
  23const TOOLTIP_OFFSET: Point<Pixels> = Point::new(px(10.0), px(8.0));
  24
  25pub struct GroupStyle {
  26    pub group: SharedString,
  27    pub style: StyleRefinement,
  28}
  29
  30pub trait InteractiveComponent<V: 'static>: Sized + Element<V> {
  31    fn interactivity(&mut self) -> &mut Interactivity<V>;
  32
  33    fn hover(mut self, f: impl FnOnce(StyleRefinement) -> StyleRefinement) -> Self
  34    where
  35        Self: Sized,
  36    {
  37        self.interactivity().hover_style = f(StyleRefinement::default());
  38        self
  39    }
  40
  41    fn group_hover(
  42        mut self,
  43        group_name: impl Into<SharedString>,
  44        f: impl FnOnce(StyleRefinement) -> StyleRefinement,
  45    ) -> Self
  46    where
  47        Self: Sized,
  48    {
  49        self.interactivity().group_hover_style = Some(GroupStyle {
  50            group: group_name.into(),
  51            style: f(StyleRefinement::default()),
  52        });
  53        self
  54    }
  55
  56    fn on_mouse_down(
  57        mut self,
  58        button: MouseButton,
  59        handler: impl Fn(&mut V, &MouseDownEvent, &mut ViewContext<V>) + 'static,
  60    ) -> Self
  61    where
  62        Self: Sized,
  63    {
  64        self.interactivity().mouse_down_listeners.push(Box::new(
  65            move |view, event, bounds, phase, cx| {
  66                if phase == DispatchPhase::Bubble
  67                    && event.button == button
  68                    && bounds.contains_point(&event.position)
  69                {
  70                    handler(view, event, cx)
  71                }
  72            },
  73        ));
  74        self
  75    }
  76
  77    fn on_mouse_up(
  78        mut self,
  79        button: MouseButton,
  80        handler: impl Fn(&mut V, &MouseUpEvent, &mut ViewContext<V>) + 'static,
  81    ) -> Self
  82    where
  83        Self: Sized,
  84    {
  85        self.interactivity().mouse_up_listeners.push(Box::new(
  86            move |view, event, bounds, phase, cx| {
  87                if phase == DispatchPhase::Bubble
  88                    && event.button == button
  89                    && bounds.contains_point(&event.position)
  90                {
  91                    handler(view, event, cx)
  92                }
  93            },
  94        ));
  95        self
  96    }
  97
  98    fn on_mouse_down_out(
  99        mut self,
 100        handler: impl Fn(&mut V, &MouseDownEvent, &mut ViewContext<V>) + 'static,
 101    ) -> Self
 102    where
 103        Self: Sized,
 104    {
 105        self.interactivity().mouse_down_listeners.push(Box::new(
 106            move |view, event, bounds, phase, cx| {
 107                if phase == DispatchPhase::Capture && !bounds.contains_point(&event.position) {
 108                    handler(view, event, cx)
 109                }
 110            },
 111        ));
 112        self
 113    }
 114
 115    fn on_mouse_up_out(
 116        mut self,
 117        button: MouseButton,
 118        handler: impl Fn(&mut V, &MouseUpEvent, &mut ViewContext<V>) + 'static,
 119    ) -> Self
 120    where
 121        Self: Sized,
 122    {
 123        self.interactivity().mouse_up_listeners.push(Box::new(
 124            move |view, event, bounds, phase, cx| {
 125                if phase == DispatchPhase::Capture
 126                    && event.button == button
 127                    && !bounds.contains_point(&event.position)
 128                {
 129                    handler(view, event, cx);
 130                }
 131            },
 132        ));
 133        self
 134    }
 135
 136    fn on_mouse_move(
 137        mut self,
 138        handler: impl Fn(&mut V, &MouseMoveEvent, &mut ViewContext<V>) + 'static,
 139    ) -> Self
 140    where
 141        Self: Sized,
 142    {
 143        self.interactivity().mouse_move_listeners.push(Box::new(
 144            move |view, event, bounds, phase, cx| {
 145                if phase == DispatchPhase::Bubble && bounds.contains_point(&event.position) {
 146                    handler(view, event, cx);
 147                }
 148            },
 149        ));
 150        self
 151    }
 152
 153    fn on_scroll_wheel(
 154        mut self,
 155        handler: impl Fn(&mut V, &ScrollWheelEvent, &mut ViewContext<V>) + 'static,
 156    ) -> Self
 157    where
 158        Self: Sized,
 159    {
 160        self.interactivity().scroll_wheel_listeners.push(Box::new(
 161            move |view, event, bounds, phase, cx| {
 162                if phase == DispatchPhase::Bubble && bounds.contains_point(&event.position) {
 163                    handler(view, event, cx);
 164                }
 165            },
 166        ));
 167        self
 168    }
 169
 170    /// Capture the given action, fires during the capture phase
 171    fn capture_action<A: Action>(
 172        mut self,
 173        listener: impl Fn(&mut V, &A, &mut ViewContext<V>) + 'static,
 174    ) -> Self
 175    where
 176        Self: Sized,
 177    {
 178        self.interactivity().action_listeners.push((
 179            TypeId::of::<A>(),
 180            Box::new(move |view, action, phase, cx| {
 181                let action = action.downcast_ref().unwrap();
 182                if phase == DispatchPhase::Capture {
 183                    listener(view, action, cx)
 184                }
 185            }),
 186        ));
 187        self
 188    }
 189
 190    /// Add a listener for the given action, fires during the bubble event phase
 191    fn on_action<A: Action>(
 192        mut self,
 193        listener: impl Fn(&mut V, &A, &mut ViewContext<V>) + 'static,
 194    ) -> Self
 195    where
 196        Self: Sized,
 197    {
 198        self.interactivity().action_listeners.push((
 199            TypeId::of::<A>(),
 200            Box::new(move |view, action, phase, cx| {
 201                let action = action.downcast_ref().unwrap();
 202                if phase == DispatchPhase::Bubble {
 203                    listener(view, action, cx)
 204                }
 205            }),
 206        ));
 207        self
 208    }
 209
 210    fn on_key_down(
 211        mut self,
 212        listener: impl Fn(&mut V, &KeyDownEvent, DispatchPhase, &mut ViewContext<V>) + 'static,
 213    ) -> Self
 214    where
 215        Self: Sized,
 216    {
 217        self.interactivity()
 218            .key_down_listeners
 219            .push(Box::new(move |view, event, phase, cx| {
 220                listener(view, event, phase, cx)
 221            }));
 222        self
 223    }
 224
 225    fn on_key_up(
 226        mut self,
 227        listener: impl Fn(&mut V, &KeyUpEvent, DispatchPhase, &mut ViewContext<V>) + 'static,
 228    ) -> Self
 229    where
 230        Self: Sized,
 231    {
 232        self.interactivity()
 233            .key_up_listeners
 234            .push(Box::new(move |view, event, phase, cx| {
 235                listener(view, event, phase, cx)
 236            }));
 237        self
 238    }
 239
 240    fn drag_over<S: 'static>(mut self, f: impl FnOnce(StyleRefinement) -> StyleRefinement) -> Self
 241    where
 242        Self: Sized,
 243    {
 244        self.interactivity()
 245            .drag_over_styles
 246            .push((TypeId::of::<S>(), f(StyleRefinement::default())));
 247        self
 248    }
 249
 250    fn group_drag_over<S: 'static>(
 251        mut self,
 252        group_name: impl Into<SharedString>,
 253        f: impl FnOnce(StyleRefinement) -> StyleRefinement,
 254    ) -> Self
 255    where
 256        Self: Sized,
 257    {
 258        self.interactivity().group_drag_over_styles.push((
 259            TypeId::of::<S>(),
 260            GroupStyle {
 261                group: group_name.into(),
 262                style: f(StyleRefinement::default()),
 263            },
 264        ));
 265        self
 266    }
 267
 268    fn on_drop<W: 'static>(
 269        mut self,
 270        listener: impl Fn(&mut V, View<W>, &mut ViewContext<V>) + 'static,
 271    ) -> Self
 272    where
 273        Self: Sized,
 274    {
 275        self.interactivity().drop_listeners.push((
 276            TypeId::of::<W>(),
 277            Box::new(move |view, dragged_view, cx| {
 278                listener(view, dragged_view.downcast().unwrap(), cx);
 279            }),
 280        ));
 281        self
 282    }
 283}
 284
 285pub trait StatefulInteractiveComponent<V: 'static, E: Element<V>>: InteractiveComponent<V> {
 286    fn active(mut self, f: impl FnOnce(StyleRefinement) -> StyleRefinement) -> Self
 287    where
 288        Self: Sized,
 289    {
 290        self.interactivity().active_style = f(StyleRefinement::default());
 291        self
 292    }
 293
 294    fn group_active(
 295        mut self,
 296        group_name: impl Into<SharedString>,
 297        f: impl FnOnce(StyleRefinement) -> StyleRefinement,
 298    ) -> Self
 299    where
 300        Self: Sized,
 301    {
 302        self.interactivity().group_active_style = Some(GroupStyle {
 303            group: group_name.into(),
 304            style: f(StyleRefinement::default()),
 305        });
 306        self
 307    }
 308
 309    fn on_click(
 310        mut self,
 311        listener: impl Fn(&mut V, &ClickEvent, &mut ViewContext<V>) + 'static,
 312    ) -> Self
 313    where
 314        Self: Sized,
 315    {
 316        self.interactivity()
 317            .click_listeners
 318            .push(Box::new(move |view, event, cx| listener(view, event, cx)));
 319        self
 320    }
 321
 322    fn on_drag<W>(
 323        mut self,
 324        listener: impl Fn(&mut V, &mut ViewContext<V>) -> View<W> + 'static,
 325    ) -> Self
 326    where
 327        Self: Sized,
 328        W: 'static + Render,
 329    {
 330        debug_assert!(
 331            self.interactivity().drag_listener.is_none(),
 332            "calling on_drag more than once on the same element is not supported"
 333        );
 334        self.interactivity().drag_listener =
 335            Some(Box::new(move |view_state, cursor_offset, cx| AnyDrag {
 336                view: listener(view_state, cx).into(),
 337                cursor_offset,
 338            }));
 339        self
 340    }
 341
 342    fn on_hover(mut self, listener: impl 'static + Fn(&mut V, bool, &mut ViewContext<V>)) -> Self
 343    where
 344        Self: Sized,
 345    {
 346        debug_assert!(
 347            self.interactivity().hover_listener.is_none(),
 348            "calling on_hover more than once on the same element is not supported"
 349        );
 350        self.interactivity().hover_listener = Some(Box::new(listener));
 351        self
 352    }
 353
 354    fn tooltip<W>(
 355        mut self,
 356        build_tooltip: impl Fn(&mut V, &mut ViewContext<V>) -> View<W> + 'static,
 357    ) -> Self
 358    where
 359        Self: Sized,
 360        W: 'static + Render,
 361    {
 362        debug_assert!(
 363            self.interactivity().tooltip_builder.is_none(),
 364            "calling tooltip more than once on the same element is not supported"
 365        );
 366        self.interactivity().tooltip_builder = Some(Arc::new(move |view_state, cx| {
 367            build_tooltip(view_state, cx).into()
 368        }));
 369
 370        self
 371    }
 372}
 373
 374pub trait FocusableComponent<V> {
 375    fn focusability(&mut self) -> &mut Focusability<V>;
 376
 377    fn focus(mut self, f: impl FnOnce(StyleRefinement) -> StyleRefinement) -> Self
 378    where
 379        Self: Sized,
 380    {
 381        self.focusability().focus_style = f(StyleRefinement::default());
 382        self
 383    }
 384
 385    fn focus_in(mut self, f: impl FnOnce(StyleRefinement) -> StyleRefinement) -> Self
 386    where
 387        Self: Sized,
 388    {
 389        self.focusability().focus_in_style = f(StyleRefinement::default());
 390        self
 391    }
 392
 393    fn in_focus(mut self, f: impl FnOnce(StyleRefinement) -> StyleRefinement) -> Self
 394    where
 395        Self: Sized,
 396    {
 397        self.focusability().in_focus_style = f(StyleRefinement::default());
 398        self
 399    }
 400
 401    fn on_focus(
 402        mut self,
 403        listener: impl Fn(&mut V, &FocusEvent, &mut ViewContext<V>) + 'static,
 404    ) -> Self
 405    where
 406        Self: Sized,
 407    {
 408        self.focusability()
 409            .focus_listeners
 410            .push(Box::new(move |view, focus_handle, event, cx| {
 411                if event.focused.as_ref() == Some(focus_handle) {
 412                    listener(view, event, cx)
 413                }
 414            }));
 415        self
 416    }
 417
 418    fn on_blur(
 419        mut self,
 420        listener: impl Fn(&mut V, &FocusEvent, &mut ViewContext<V>) + 'static,
 421    ) -> Self
 422    where
 423        Self: Sized,
 424    {
 425        self.focusability()
 426            .focus_listeners
 427            .push(Box::new(move |view, focus_handle, event, cx| {
 428                if event.blurred.as_ref() == Some(focus_handle) {
 429                    listener(view, event, cx)
 430                }
 431            }));
 432        self
 433    }
 434
 435    fn on_focus_in(
 436        mut self,
 437        listener: impl Fn(&mut V, &FocusEvent, &mut ViewContext<V>) + 'static,
 438    ) -> Self
 439    where
 440        Self: Sized,
 441    {
 442        self.focusability()
 443            .focus_listeners
 444            .push(Box::new(move |view, focus_handle, event, cx| {
 445                let descendant_blurred = event
 446                    .blurred
 447                    .as_ref()
 448                    .map_or(false, |blurred| focus_handle.contains(blurred, cx));
 449                let descendant_focused = event
 450                    .focused
 451                    .as_ref()
 452                    .map_or(false, |focused| focus_handle.contains(focused, cx));
 453
 454                if !descendant_blurred && descendant_focused {
 455                    listener(view, event, cx)
 456                }
 457            }));
 458        self
 459    }
 460
 461    fn on_focus_out(
 462        mut self,
 463        listener: impl Fn(&mut V, &FocusEvent, &mut ViewContext<V>) + 'static,
 464    ) -> Self
 465    where
 466        Self: Sized,
 467    {
 468        self.focusability()
 469            .focus_listeners
 470            .push(Box::new(move |view, focus_handle, event, cx| {
 471                let descendant_blurred = event
 472                    .blurred
 473                    .as_ref()
 474                    .map_or(false, |blurred| focus_handle.contains(blurred, cx));
 475                let descendant_focused = event
 476                    .focused
 477                    .as_ref()
 478                    .map_or(false, |focused| focus_handle.contains(focused, cx));
 479                if descendant_blurred && !descendant_focused {
 480                    listener(view, event, cx)
 481                }
 482            }));
 483        self
 484    }
 485}
 486
 487pub type FocusListeners<V> = SmallVec<[FocusListener<V>; 2]>;
 488
 489pub type FocusListener<V> =
 490    Box<dyn Fn(&mut V, &FocusHandle, &FocusEvent, &mut ViewContext<V>) + 'static>;
 491
 492pub type MouseDownListener<V> = Box<
 493    dyn Fn(&mut V, &MouseDownEvent, &Bounds<Pixels>, DispatchPhase, &mut ViewContext<V>) + 'static,
 494>;
 495pub type MouseUpListener<V> = Box<
 496    dyn Fn(&mut V, &MouseUpEvent, &Bounds<Pixels>, DispatchPhase, &mut ViewContext<V>) + 'static,
 497>;
 498
 499pub type MouseMoveListener<V> = Box<
 500    dyn Fn(&mut V, &MouseMoveEvent, &Bounds<Pixels>, DispatchPhase, &mut ViewContext<V>) + 'static,
 501>;
 502
 503pub type ScrollWheelListener<V> = Box<
 504    dyn Fn(&mut V, &ScrollWheelEvent, &Bounds<Pixels>, DispatchPhase, &mut ViewContext<V>)
 505        + 'static,
 506>;
 507
 508pub type ClickListener<V> = Box<dyn Fn(&mut V, &ClickEvent, &mut ViewContext<V>) + 'static>;
 509
 510pub type DragListener<V> =
 511    Box<dyn Fn(&mut V, Point<Pixels>, &mut ViewContext<V>) -> AnyDrag + 'static>;
 512
 513type DropListener<V> = dyn Fn(&mut V, AnyView, &mut ViewContext<V>) + 'static;
 514
 515pub type HoverListener<V> = Box<dyn Fn(&mut V, bool, &mut ViewContext<V>) + 'static>;
 516
 517pub type TooltipBuilder<V> = Arc<dyn Fn(&mut V, &mut ViewContext<V>) -> AnyView + 'static>;
 518
 519pub type KeyDownListener<V> =
 520    Box<dyn Fn(&mut V, &KeyDownEvent, DispatchPhase, &mut ViewContext<V>) + 'static>;
 521
 522pub type KeyUpListener<V> =
 523    Box<dyn Fn(&mut V, &KeyUpEvent, DispatchPhase, &mut ViewContext<V>) + 'static>;
 524
 525pub type ActionListener<V> =
 526    Box<dyn Fn(&mut V, &dyn Any, DispatchPhase, &mut ViewContext<V>) + 'static>;
 527
 528pub struct FocusEvent {
 529    pub blurred: Option<FocusHandle>,
 530    pub focused: Option<FocusHandle>,
 531}
 532
 533pub struct Node<V> {
 534    interactivity: Interactivity<V>,
 535    children: Vec<AnyElement<V>>,
 536}
 537
 538impl<V> Styled for Node<V> {
 539    fn style(&mut self) -> &mut StyleRefinement {
 540        &mut self.interactivity.base_style
 541    }
 542}
 543
 544impl<V: 'static> InteractiveComponent<V> for Node<V> {
 545    fn interactivity(&mut self) -> &mut Interactivity<V> {
 546        &mut self.interactivity
 547    }
 548}
 549
 550impl<V: 'static> Element<V> for Node<V> {
 551    type ElementState = NodeState;
 552
 553    fn id(&self) -> Option<crate::ElementId> {
 554        None
 555    }
 556
 557    fn initialize(
 558        &mut self,
 559        view_state: &mut V,
 560        element_state: Option<Self::ElementState>,
 561        cx: &mut ViewContext<V>,
 562    ) -> Self::ElementState {
 563        let interactive_state =
 564            self.interactivity
 565                .initialize(element_state.map(|s| s.interactive_state), cx, |cx| {
 566                    for child in &mut self.children {
 567                        child.initialize(view_state, cx);
 568                    }
 569                });
 570
 571        NodeState {
 572            interactive_state,
 573            child_layout_ids: SmallVec::new(),
 574        }
 575    }
 576
 577    fn layout(
 578        &mut self,
 579        view_state: &mut V,
 580        element_state: &mut Self::ElementState,
 581        cx: &mut ViewContext<V>,
 582    ) -> crate::LayoutId {
 583        let mut interactivity = mem::take(&mut self.interactivity);
 584        let layout_id =
 585            interactivity.layout(&mut element_state.interactive_state, cx, |style, cx| {
 586                cx.with_text_style(style.text_style().cloned(), |cx| {
 587                    element_state.child_layout_ids = self
 588                        .children
 589                        .iter_mut()
 590                        .map(|child| child.layout(view_state, cx))
 591                        .collect::<SmallVec<_>>();
 592                    cx.request_layout(&style, element_state.child_layout_ids.iter().copied())
 593                })
 594            });
 595        self.interactivity = interactivity;
 596        layout_id
 597    }
 598
 599    fn paint(
 600        &mut self,
 601        bounds: Bounds<Pixels>,
 602        view_state: &mut V,
 603        element_state: &mut Self::ElementState,
 604        cx: &mut ViewContext<V>,
 605    ) {
 606        let mut interactivity = mem::take(&mut self.interactivity);
 607
 608        let mut child_min = point(Pixels::MAX, Pixels::MAX);
 609        let mut child_max = Point::default();
 610        let content_size = if element_state.child_layout_ids.is_empty() {
 611            bounds.size
 612        } else {
 613            for child_layout_id in &element_state.child_layout_ids {
 614                let child_bounds = cx.layout_bounds(*child_layout_id);
 615                child_min = child_min.min(&child_bounds.origin);
 616                child_max = child_max.max(&child_bounds.lower_right());
 617            }
 618            (child_max - child_min).into()
 619        };
 620
 621        interactivity.paint(
 622            bounds,
 623            content_size,
 624            &mut element_state.interactive_state,
 625            cx,
 626            |style, scroll_offset, cx| {
 627                if style.visibility == Visibility::Hidden {
 628                    return;
 629                }
 630
 631                let z_index = style.z_index.unwrap_or(0);
 632
 633                cx.with_z_index(z_index, |cx| {
 634                    cx.with_z_index(0, |cx| {
 635                        style.paint(bounds, cx);
 636                    });
 637                    cx.with_z_index(1, |cx| {
 638                        cx.with_text_style(style.text_style().cloned(), |cx| {
 639                            cx.with_content_mask(style.overflow_mask(bounds), |cx| {
 640                                cx.with_element_offset(scroll_offset, |cx| {
 641                                    for child in &mut self.children {
 642                                        child.paint(view_state, cx);
 643                                    }
 644                                })
 645                            })
 646                        })
 647                    })
 648                })
 649            },
 650        );
 651        self.interactivity = interactivity;
 652    }
 653}
 654
 655pub struct NodeState {
 656    child_layout_ids: SmallVec<[LayoutId; 4]>,
 657    interactive_state: InteractiveElementState,
 658}
 659
 660impl AsMut<InteractiveElementState> for InteractiveElementState {
 661    fn as_mut(&mut self) -> &mut InteractiveElementState {
 662        self
 663    }
 664}
 665
 666pub struct Interactivity<V> {
 667    hovered: bool,
 668    group_hovered: bool,
 669    key_context: KeyContext,
 670    tracked_focus_handle: Option<FocusHandle>,
 671    focusable: bool,
 672    scroll_offset: Point<Pixels>,
 673    group: Option<SharedString>,
 674    base_style: StyleRefinement,
 675    focus_style: StyleRefinement,
 676    focus_in_style: StyleRefinement,
 677    in_focus_style: StyleRefinement,
 678    hover_style: StyleRefinement,
 679    group_hover_style: Option<GroupStyle>,
 680    active_style: StyleRefinement,
 681    group_active_style: Option<GroupStyle>,
 682    drag_over_styles: SmallVec<[(TypeId, StyleRefinement); 2]>,
 683    group_drag_over_styles: SmallVec<[(TypeId, GroupStyle); 2]>,
 684    mouse_down_listeners: SmallVec<[MouseDownListener<V>; 2]>,
 685    mouse_up_listeners: SmallVec<[MouseUpListener<V>; 2]>,
 686    mouse_move_listeners: SmallVec<[MouseMoveListener<V>; 2]>,
 687    scroll_wheel_listeners: SmallVec<[ScrollWheelListener<V>; 2]>,
 688    key_down_listeners: SmallVec<[KeyDownListener<V>; 2]>,
 689    key_up_listeners: SmallVec<[KeyUpListener<V>; 2]>,
 690    action_listeners: SmallVec<[(TypeId, ActionListener<V>); 8]>,
 691    drop_listeners: SmallVec<[(TypeId, Box<DropListener<V>>); 2]>,
 692    click_listeners: SmallVec<[ClickListener<V>; 2]>,
 693    drag_listener: Option<DragListener<V>>,
 694    hover_listener: Option<HoverListener<V>>,
 695    tooltip_builder: Option<TooltipBuilder<V>>,
 696}
 697
 698impl<V> Interactivity<V>
 699where
 700    V: 'static,
 701{
 702    fn initialize(
 703        &mut self,
 704        element_state: Option<InteractiveElementState>,
 705        cx: &mut ViewContext<V>,
 706        f: impl FnOnce(&mut ViewContext<V>),
 707    ) -> InteractiveElementState {
 708        let mut element_state = element_state.unwrap_or_default();
 709        // Ensure we store a focus handle in our element state if we're focusable.
 710        // If there's an explicit focus handle we're tracking, use that. Otherwise
 711        // create a new handle and store it in the element state, which lives for as
 712        // as frames contain an element with this id.
 713        if self.focusable {
 714            element_state.focus_handle.get_or_insert_with(|| {
 715                self.tracked_focus_handle
 716                    .clone()
 717                    .unwrap_or_else(|| cx.focus_handle())
 718            });
 719        }
 720        element_state
 721    }
 722
 723    fn layout(
 724        &mut self,
 725        element_state: &mut InteractiveElementState,
 726        cx: &mut ViewContext<V>,
 727        f: impl FnOnce(Style, &mut ViewContext<V>) -> LayoutId,
 728    ) -> LayoutId {
 729        let style = self.compute_style(None, element_state, cx);
 730        cx.with_key_dispatch(
 731            self.key_context.clone(),
 732            self.tracked_focus_handle.clone(),
 733            |_, cx| f(style, cx),
 734        )
 735    }
 736
 737    fn paint(
 738        &mut self,
 739        bounds: Bounds<Pixels>,
 740        content_size: Size<Pixels>,
 741        element_state: &mut InteractiveElementState,
 742        cx: &mut ViewContext<V>,
 743        f: impl FnOnce(Style, Point<Pixels>, &mut ViewContext<V>),
 744    ) {
 745        let style = self.compute_style(Some(bounds), element_state, cx);
 746
 747        if let Some(mouse_cursor) = style.mouse_cursor {
 748            let hovered = bounds.contains_point(&cx.mouse_position());
 749            if hovered {
 750                cx.set_cursor_style(mouse_cursor);
 751            }
 752        }
 753
 754        for listener in self.mouse_down_listeners.drain(..) {
 755            cx.on_mouse_event(move |state, event: &MouseDownEvent, phase, cx| {
 756                listener(state, event, &bounds, phase, cx);
 757            })
 758        }
 759
 760        for listener in self.mouse_up_listeners.drain(..) {
 761            cx.on_mouse_event(move |state, event: &MouseUpEvent, phase, cx| {
 762                listener(state, event, &bounds, phase, cx);
 763            })
 764        }
 765
 766        for listener in self.mouse_move_listeners.drain(..) {
 767            cx.on_mouse_event(move |state, event: &MouseMoveEvent, phase, cx| {
 768                listener(state, event, &bounds, phase, cx);
 769            })
 770        }
 771
 772        for listener in self.scroll_wheel_listeners.drain(..) {
 773            cx.on_mouse_event(move |state, event: &ScrollWheelEvent, phase, cx| {
 774                listener(state, event, &bounds, phase, cx);
 775            })
 776        }
 777
 778        let hover_group_bounds = self
 779            .group_hover_style
 780            .as_ref()
 781            .and_then(|group_hover| GroupBounds::get(&group_hover.group, cx));
 782
 783        if let Some(group_bounds) = hover_group_bounds {
 784            let hovered = group_bounds.contains_point(&cx.mouse_position());
 785            cx.on_mouse_event(move |_, event: &MouseMoveEvent, phase, cx| {
 786                if phase == DispatchPhase::Capture {
 787                    if group_bounds.contains_point(&event.position) != hovered {
 788                        cx.notify();
 789                    }
 790                }
 791            });
 792        }
 793
 794        if self.hover_style.is_some()
 795            || (cx.active_drag.is_some() && !self.drag_over_styles.is_empty())
 796        {
 797            let hovered = bounds.contains_point(&cx.mouse_position());
 798            cx.on_mouse_event(move |_, event: &MouseMoveEvent, phase, cx| {
 799                if phase == DispatchPhase::Capture {
 800                    if bounds.contains_point(&event.position) != hovered {
 801                        cx.notify();
 802                    }
 803                }
 804            });
 805        }
 806
 807        if cx.active_drag.is_some() {
 808            let drop_listeners = mem::take(&mut self.drop_listeners);
 809            cx.on_mouse_event(move |view, event: &MouseUpEvent, phase, cx| {
 810                if phase == DispatchPhase::Bubble && bounds.contains_point(&event.position) {
 811                    if let Some(drag_state_type) =
 812                        cx.active_drag.as_ref().map(|drag| drag.view.entity_type())
 813                    {
 814                        for (drop_state_type, listener) in &drop_listeners {
 815                            if *drop_state_type == drag_state_type {
 816                                let drag = cx
 817                                    .active_drag
 818                                    .take()
 819                                    .expect("checked for type drag state type above");
 820                                listener(view, drag.view.clone(), cx);
 821                                cx.notify();
 822                                cx.stop_propagation();
 823                            }
 824                        }
 825                    }
 826                }
 827            });
 828        }
 829
 830        let click_listeners = mem::take(&mut self.click_listeners);
 831        let drag_listener = mem::take(&mut self.drag_listener);
 832
 833        if !click_listeners.is_empty() || drag_listener.is_some() {
 834            let pending_mouse_down = element_state.pending_mouse_down.clone();
 835            let mouse_down = pending_mouse_down.lock().clone();
 836            if let Some(mouse_down) = mouse_down {
 837                if let Some(drag_listener) = drag_listener {
 838                    let active_state = element_state.clicked_state.clone();
 839
 840                    cx.on_mouse_event(move |view_state, event: &MouseMoveEvent, phase, cx| {
 841                        if cx.active_drag.is_some() {
 842                            if phase == DispatchPhase::Capture {
 843                                cx.notify();
 844                            }
 845                        } else if phase == DispatchPhase::Bubble
 846                            && bounds.contains_point(&event.position)
 847                            && (event.position - mouse_down.position).magnitude() > DRAG_THRESHOLD
 848                        {
 849                            *active_state.lock() = ElementClickedState::default();
 850                            let cursor_offset = event.position - bounds.origin;
 851                            let drag = drag_listener(view_state, cursor_offset, cx);
 852                            cx.active_drag = Some(drag);
 853                            cx.notify();
 854                            cx.stop_propagation();
 855                        }
 856                    });
 857                }
 858
 859                cx.on_mouse_event(move |view_state, event: &MouseUpEvent, phase, cx| {
 860                    if phase == DispatchPhase::Bubble && bounds.contains_point(&event.position) {
 861                        let mouse_click = ClickEvent {
 862                            down: mouse_down.clone(),
 863                            up: event.clone(),
 864                        };
 865                        for listener in &click_listeners {
 866                            listener(view_state, &mouse_click, cx);
 867                        }
 868                    }
 869                    *pending_mouse_down.lock() = None;
 870                });
 871            } else {
 872                cx.on_mouse_event(move |_state, event: &MouseDownEvent, phase, _cx| {
 873                    if phase == DispatchPhase::Bubble && bounds.contains_point(&event.position) {
 874                        *pending_mouse_down.lock() = Some(event.clone());
 875                    }
 876                });
 877            }
 878        }
 879
 880        if let Some(hover_listener) = self.hover_listener.take() {
 881            let was_hovered = element_state.hover_state.clone();
 882            let has_mouse_down = element_state.pending_mouse_down.clone();
 883
 884            cx.on_mouse_event(move |view_state, event: &MouseMoveEvent, phase, cx| {
 885                if phase != DispatchPhase::Bubble {
 886                    return;
 887                }
 888                let is_hovered =
 889                    bounds.contains_point(&event.position) && has_mouse_down.lock().is_none();
 890                let mut was_hovered = was_hovered.lock();
 891
 892                if is_hovered != was_hovered.clone() {
 893                    *was_hovered = is_hovered;
 894                    drop(was_hovered);
 895
 896                    hover_listener(view_state, is_hovered, cx);
 897                }
 898            });
 899        }
 900
 901        if let Some(tooltip_builder) = self.tooltip_builder.take() {
 902            let active_tooltip = element_state.active_tooltip.clone();
 903            let pending_mouse_down = element_state.pending_mouse_down.clone();
 904
 905            cx.on_mouse_event(move |_, event: &MouseMoveEvent, phase, cx| {
 906                if phase != DispatchPhase::Bubble {
 907                    return;
 908                }
 909
 910                let is_hovered =
 911                    bounds.contains_point(&event.position) && pending_mouse_down.lock().is_none();
 912                if !is_hovered {
 913                    active_tooltip.lock().take();
 914                    return;
 915                }
 916
 917                if active_tooltip.lock().is_none() {
 918                    let task = cx.spawn({
 919                        let active_tooltip = active_tooltip.clone();
 920                        let tooltip_builder = tooltip_builder.clone();
 921
 922                        move |view, mut cx| async move {
 923                            cx.background_executor().timer(TOOLTIP_DELAY).await;
 924                            view.update(&mut cx, move |view_state, cx| {
 925                                active_tooltip.lock().replace(ActiveTooltip {
 926                                    waiting: None,
 927                                    tooltip: Some(AnyTooltip {
 928                                        view: tooltip_builder(view_state, cx),
 929                                        cursor_offset: cx.mouse_position() + TOOLTIP_OFFSET,
 930                                    }),
 931                                });
 932                                cx.notify();
 933                            })
 934                            .ok();
 935                        }
 936                    });
 937                    active_tooltip.lock().replace(ActiveTooltip {
 938                        waiting: Some(task),
 939                        tooltip: None,
 940                    });
 941                }
 942            });
 943
 944            if let Some(active_tooltip) = element_state.active_tooltip.lock().as_ref() {
 945                if active_tooltip.tooltip.is_some() {
 946                    cx.active_tooltip = active_tooltip.tooltip.clone()
 947                }
 948            }
 949        }
 950
 951        let active_state = element_state.clicked_state.clone();
 952        if !active_state.lock().is_clicked() {
 953            cx.on_mouse_event(move |_, _: &MouseUpEvent, phase, cx| {
 954                if phase == DispatchPhase::Capture {
 955                    *active_state.lock() = ElementClickedState::default();
 956                    cx.notify();
 957                }
 958            });
 959        } else {
 960            let active_group_bounds = self
 961                .group_active_style
 962                .as_ref()
 963                .and_then(|group_active| GroupBounds::get(&group_active.group, cx));
 964            cx.on_mouse_event(move |_view, down: &MouseDownEvent, phase, cx| {
 965                if phase == DispatchPhase::Bubble {
 966                    let group = active_group_bounds
 967                        .map_or(false, |bounds| bounds.contains_point(&down.position));
 968                    let element = bounds.contains_point(&down.position);
 969                    if group || element {
 970                        *active_state.lock() = ElementClickedState { group, element };
 971                        cx.notify();
 972                    }
 973                }
 974            });
 975        }
 976
 977        let overflow = style.overflow;
 978        if overflow.x == Overflow::Scroll || overflow.y == Overflow::Scroll {
 979            let scroll_offset = element_state
 980                .scroll_offset
 981                .get_or_insert_with(Arc::default)
 982                .clone();
 983            let line_height = cx.line_height();
 984            let scroll_max = (content_size - bounds.size).max(&Size::default());
 985
 986            cx.on_mouse_event(move |_, event: &ScrollWheelEvent, phase, cx| {
 987                if phase == DispatchPhase::Bubble && bounds.contains_point(&event.position) {
 988                    let mut scroll_offset = scroll_offset.lock();
 989                    let old_scroll_offset = *scroll_offset;
 990                    let delta = event.delta.pixel_delta(line_height);
 991
 992                    if overflow.x == Overflow::Scroll {
 993                        scroll_offset.x =
 994                            (scroll_offset.x + delta.x).clamp(-scroll_max.width, px(0.));
 995                    }
 996
 997                    if overflow.y == Overflow::Scroll {
 998                        scroll_offset.y =
 999                            (scroll_offset.y + delta.y).clamp(-scroll_max.height, px(0.));
1000                    }
1001
1002                    if *scroll_offset != old_scroll_offset {
1003                        cx.notify();
1004                        cx.stop_propagation();
1005                    }
1006                }
1007            });
1008        }
1009
1010        if let Some(group) = self.group.clone() {
1011            GroupBounds::push(group, bounds, cx);
1012        }
1013
1014        cx.with_key_dispatch(
1015            self.key_context.clone(),
1016            self.tracked_focus_handle.clone(),
1017            |_, cx| {
1018                for listener in self.key_down_listeners.drain(..) {
1019                    cx.on_key_event(move |state, event: &KeyDownEvent, phase, cx| {
1020                        listener(state, event, phase, cx);
1021                    })
1022                }
1023
1024                for listener in self.key_up_listeners.drain(..) {
1025                    cx.on_key_event(move |state, event: &KeyUpEvent, phase, cx| {
1026                        listener(state, event, phase, cx);
1027                    })
1028                }
1029
1030                for (action_type, listener) in self.action_listeners.drain(..) {
1031                    cx.on_action(action_type, listener)
1032                }
1033
1034                f(style, self.scroll_offset, cx)
1035            },
1036        );
1037
1038        if let Some(group) = self.group.as_ref() {
1039            GroupBounds::pop(group, cx);
1040        }
1041    }
1042
1043    fn compute_style(
1044        &self,
1045        bounds: Option<Bounds<Pixels>>,
1046        element_state: &mut InteractiveElementState,
1047        cx: &mut ViewContext<V>,
1048    ) -> Style {
1049        let mut style = Style::default();
1050        style.refine(&self.base_style);
1051
1052        if let Some(focus_handle) = self.tracked_focus_handle.as_ref() {
1053            if focus_handle.contains_focused(cx) {
1054                style.refine(&self.focus_in_style);
1055            }
1056
1057            if focus_handle.within_focused(cx) {
1058                style.refine(&self.in_focus_style);
1059            }
1060
1061            if focus_handle.is_focused(cx) {
1062                style.refine(&self.focus_style);
1063            }
1064        }
1065
1066        if let Some(bounds) = bounds {
1067            let mouse_position = cx.mouse_position();
1068            if let Some(group_hover) = self.group_hover_style.as_ref() {
1069                if let Some(group_bounds) = GroupBounds::get(&group_hover.group, cx) {
1070                    if group_bounds.contains_point(&mouse_position) {
1071                        style.refine(&group_hover.style);
1072                    }
1073                }
1074            }
1075            if bounds.contains_point(&mouse_position) {
1076                style.refine(&self.hover_style);
1077            }
1078
1079            if let Some(drag) = cx.active_drag.take() {
1080                for (state_type, group_drag_style) in &self.group_drag_over_styles {
1081                    if let Some(group_bounds) = GroupBounds::get(&group_drag_style.group, cx) {
1082                        if *state_type == drag.view.entity_type()
1083                            && group_bounds.contains_point(&mouse_position)
1084                        {
1085                            style.refine(&group_drag_style.style);
1086                        }
1087                    }
1088                }
1089
1090                for (state_type, drag_over_style) in &self.drag_over_styles {
1091                    if *state_type == drag.view.entity_type()
1092                        && bounds.contains_point(&mouse_position)
1093                    {
1094                        style.refine(drag_over_style);
1095                    }
1096                }
1097
1098                cx.active_drag = Some(drag);
1099            }
1100        }
1101
1102        let clicked_state = element_state.clicked_state.lock();
1103        if clicked_state.group {
1104            if let Some(group) = self.group_active_style.as_ref() {
1105                style.refine(&group.style)
1106            }
1107        }
1108
1109        if clicked_state.element {
1110            style.refine(&self.active_style)
1111        }
1112
1113        style
1114    }
1115}
1116
1117impl<V: 'static> Default for Interactivity<V> {
1118    fn default() -> Self {
1119        Self {
1120            hovered: false,
1121            group_hovered: false,
1122            key_context: KeyContext::default(),
1123            tracked_focus_handle: None,
1124            scroll_offset: Point::default(),
1125            group: None,
1126            base_style: StyleRefinement::default(),
1127            focus_style: StyleRefinement::default(),
1128            focus_in_style: StyleRefinement::default(),
1129            in_focus_style: StyleRefinement::default(),
1130            hover_style: StyleRefinement::default(),
1131            group_hover_style: None,
1132            active_style: StyleRefinement::default(),
1133            group_active_style: None,
1134            drag_over_styles: SmallVec::new(),
1135            group_drag_over_styles: SmallVec::new(),
1136            mouse_down_listeners: SmallVec::new(),
1137            mouse_up_listeners: SmallVec::new(),
1138            mouse_move_listeners: SmallVec::new(),
1139            scroll_wheel_listeners: SmallVec::new(),
1140            key_down_listeners: SmallVec::new(),
1141            key_up_listeners: SmallVec::new(),
1142            action_listeners: SmallVec::new(),
1143            drop_listeners: SmallVec::new(),
1144            click_listeners: SmallVec::new(),
1145            drag_listener: None,
1146            hover_listener: None,
1147            tooltip_builder: None,
1148            focusable: false,
1149        }
1150    }
1151}
1152
1153#[derive(Default)]
1154pub struct InteractiveElementState {
1155    focus_handle: Option<FocusHandle>,
1156    clicked_state: Arc<Mutex<ElementClickedState>>,
1157    hover_state: Arc<Mutex<bool>>,
1158    pending_mouse_down: Arc<Mutex<Option<MouseDownEvent>>>,
1159    scroll_offset: Option<Arc<Mutex<Point<Pixels>>>>,
1160    active_tooltip: Arc<Mutex<Option<ActiveTooltip>>>,
1161}
1162
1163struct ActiveTooltip {
1164    #[allow(unused)] // used to drop the task
1165    waiting: Option<Task<()>>,
1166    tooltip: Option<AnyTooltip>,
1167}
1168
1169/// Whether or not the element or a group that contains it is clicked by the mouse.
1170#[derive(Copy, Clone, Default, Eq, PartialEq)]
1171struct ElementClickedState {
1172    pub group: bool,
1173    pub element: bool,
1174}
1175
1176impl ElementClickedState {
1177    fn is_clicked(&self) -> bool {
1178        self.group || self.element
1179    }
1180}
1181
1182#[derive(Default)]
1183pub struct GroupBounds(HashMap<SharedString, SmallVec<[Bounds<Pixels>; 1]>>);
1184
1185impl GroupBounds {
1186    pub fn get(name: &SharedString, cx: &mut AppContext) -> Option<Bounds<Pixels>> {
1187        cx.default_global::<Self>()
1188            .0
1189            .get(name)
1190            .and_then(|bounds_stack| bounds_stack.last())
1191            .cloned()
1192    }
1193
1194    pub fn push(name: SharedString, bounds: Bounds<Pixels>, cx: &mut AppContext) {
1195        cx.default_global::<Self>()
1196            .0
1197            .entry(name)
1198            .or_default()
1199            .push(bounds);
1200    }
1201
1202    pub fn pop(name: &SharedString, cx: &mut AppContext) {
1203        cx.default_global::<Self>().0.get_mut(name).unwrap().pop();
1204    }
1205}
1206
1207pub struct Focusable<V, E> {
1208    focusability: Focusability<V>,
1209    view_type: PhantomData<V>,
1210    element: E,
1211}
1212
1213pub struct Focusability<V> {
1214    focus_handle: Option<FocusHandle>,
1215    focus_listeners: FocusListeners<V>,
1216    focus_style: StyleRefinement,
1217    focus_in_style: StyleRefinement,
1218    in_focus_style: StyleRefinement,
1219}
1220
1221impl<V, E> FocusableComponent<V> for Focusable<V, E> {
1222    fn focusability(&mut self) -> &mut Focusability<V> {
1223        &mut self.focusability
1224    }
1225}
1226
1227impl<V, E> InteractiveComponent<V> for Focusable<V, E>
1228where
1229    V: 'static,
1230    E: InteractiveComponent<V>,
1231{
1232    fn interactivity(&mut self) -> &mut Interactivity<V> {
1233        self.element.interactivity()
1234    }
1235}
1236
1237impl<V: 'static, E: StatefulInteractiveComponent<V, E>> StatefulInteractiveComponent<V, E>
1238    for Focusable<V, E>
1239{
1240}
1241
1242impl<V, E> Element<V> for Focusable<V, E>
1243where
1244    V: 'static,
1245    E: Element<V>,
1246{
1247    type ElementState = E::ElementState;
1248
1249    fn id(&self) -> Option<crate::ElementId> {
1250        self.element.id()
1251    }
1252
1253    fn initialize(
1254        &mut self,
1255        view_state: &mut V,
1256        element_state: Option<Self::ElementState>,
1257        cx: &mut ViewContext<V>,
1258    ) -> Self::ElementState {
1259        todo!()
1260    }
1261
1262    fn layout(
1263        &mut self,
1264        view_state: &mut V,
1265        element_state: &mut Self::ElementState,
1266        cx: &mut ViewContext<V>,
1267    ) -> LayoutId {
1268        todo!()
1269    }
1270
1271    fn paint(
1272        &mut self,
1273        bounds: Bounds<Pixels>,
1274        view_state: &mut V,
1275        element_state: &mut Self::ElementState,
1276        cx: &mut ViewContext<V>,
1277    ) {
1278        todo!()
1279    }
1280}
1281
1282pub struct Stateful<V, E> {
1283    id: SharedString,
1284    view_type: PhantomData<V>,
1285    element: E,
1286}
1287
1288impl<V, E> StatefulInteractiveComponent<V, E> for Stateful<V, E>
1289where
1290    V: 'static,
1291    E: Element<V>,
1292    Self: InteractiveComponent<V>,
1293{
1294}
1295
1296impl<V, E> InteractiveComponent<V> for Stateful<V, E>
1297where
1298    V: 'static,
1299    E: InteractiveComponent<V>,
1300{
1301    fn interactivity(&mut self) -> &mut Interactivity<V> {
1302        self.element.interactivity()
1303    }
1304}
1305
1306impl<V, E: FocusableComponent<V>> FocusableComponent<V> for Stateful<V, E> {
1307    fn focusability(&mut self) -> &mut Focusability<V> {
1308        self.element.focusability()
1309    }
1310}
1311
1312impl<V, E> Element<V> for Stateful<V, E>
1313where
1314    V: 'static,
1315    E: Element<V>,
1316{
1317    type ElementState = InteractiveElementState;
1318
1319    fn id(&self) -> Option<crate::ElementId> {
1320        todo!()
1321    }
1322
1323    fn initialize(
1324        &mut self,
1325        view_state: &mut V,
1326        element_state: Option<Self::ElementState>,
1327        cx: &mut ViewContext<V>,
1328    ) -> Self::ElementState {
1329        todo!()
1330    }
1331
1332    fn layout(
1333        &mut self,
1334        view_state: &mut V,
1335        element_state: &mut Self::ElementState,
1336        cx: &mut ViewContext<V>,
1337    ) -> LayoutId {
1338        todo!()
1339    }
1340
1341    fn paint(
1342        &mut self,
1343        bounds: Bounds<Pixels>,
1344        view_state: &mut V,
1345        element_state: &mut Self::ElementState,
1346        cx: &mut ViewContext<V>,
1347    ) {
1348        todo!()
1349    }
1350}