interactive.rs

   1use crate::{
   2    point, px, view, Action, AnyDrag, AppContext, BorrowWindow, Bounds, DispatchContext,
   3    DispatchPhase, Element, ElementId, FocusHandle, KeyMatch, Keystroke, Modifiers, Overflow,
   4    Pixels, Point, SharedString, Size, Style, StyleRefinement, ViewContext,
   5};
   6use collections::HashMap;
   7use derive_more::{Deref, DerefMut};
   8use parking_lot::Mutex;
   9use refineable::Refineable;
  10use smallvec::SmallVec;
  11use std::{
  12    any::{Any, TypeId},
  13    fmt::Debug,
  14    marker::PhantomData,
  15    ops::Deref,
  16    sync::Arc,
  17};
  18
  19pub trait StatelessInteractive: Element {
  20    fn stateless_interactivity(&mut self) -> &mut StatelessInteraction<Self::ViewState>;
  21
  22    fn hover(mut self, f: impl FnOnce(StyleRefinement) -> StyleRefinement) -> Self
  23    where
  24        Self: Sized,
  25    {
  26        self.stateless_interactivity().hover_style = f(StyleRefinement::default());
  27        self
  28    }
  29
  30    fn group_hover(
  31        mut self,
  32        group_name: impl Into<SharedString>,
  33        f: impl FnOnce(StyleRefinement) -> StyleRefinement,
  34    ) -> Self
  35    where
  36        Self: Sized,
  37    {
  38        self.stateless_interactivity().group_hover_style = Some(GroupStyle {
  39            group: group_name.into(),
  40            style: f(StyleRefinement::default()),
  41        });
  42        self
  43    }
  44
  45    fn on_mouse_down(
  46        mut self,
  47        button: MouseButton,
  48        handler: impl Fn(&mut Self::ViewState, &MouseDownEvent, &mut ViewContext<Self::ViewState>)
  49            + Send
  50            + Sync
  51            + 'static,
  52    ) -> Self
  53    where
  54        Self: Sized,
  55    {
  56        self.stateless_interactivity()
  57            .mouse_down_listeners
  58            .push(Arc::new(move |view, event, bounds, phase, cx| {
  59                if phase == DispatchPhase::Bubble
  60                    && event.button == button
  61                    && bounds.contains_point(&event.position)
  62                {
  63                    handler(view, event, cx)
  64                }
  65            }));
  66        self
  67    }
  68
  69    fn on_mouse_up(
  70        mut self,
  71        button: MouseButton,
  72        handler: impl Fn(&mut Self::ViewState, &MouseUpEvent, &mut ViewContext<Self::ViewState>)
  73            + Send
  74            + Sync
  75            + 'static,
  76    ) -> Self
  77    where
  78        Self: Sized,
  79    {
  80        self.stateless_interactivity()
  81            .mouse_up_listeners
  82            .push(Arc::new(move |view, event, bounds, phase, cx| {
  83                if phase == DispatchPhase::Bubble
  84                    && event.button == button
  85                    && bounds.contains_point(&event.position)
  86                {
  87                    handler(view, event, cx)
  88                }
  89            }));
  90        self
  91    }
  92
  93    fn on_mouse_down_out(
  94        mut self,
  95        button: MouseButton,
  96        handler: impl Fn(&mut Self::ViewState, &MouseDownEvent, &mut ViewContext<Self::ViewState>)
  97            + Send
  98            + Sync
  99            + 'static,
 100    ) -> Self
 101    where
 102        Self: Sized,
 103    {
 104        self.stateless_interactivity()
 105            .mouse_down_listeners
 106            .push(Arc::new(move |view, event, bounds, phase, cx| {
 107                if phase == DispatchPhase::Capture
 108                    && event.button == button
 109                    && !bounds.contains_point(&event.position)
 110                {
 111                    handler(view, event, cx)
 112                }
 113            }));
 114        self
 115    }
 116
 117    fn on_mouse_up_out(
 118        mut self,
 119        button: MouseButton,
 120        handler: impl Fn(&mut Self::ViewState, &MouseUpEvent, &mut ViewContext<Self::ViewState>)
 121            + Send
 122            + Sync
 123            + 'static,
 124    ) -> Self
 125    where
 126        Self: Sized,
 127    {
 128        self.stateless_interactivity()
 129            .mouse_up_listeners
 130            .push(Arc::new(move |view, event, bounds, phase, cx| {
 131                if phase == DispatchPhase::Capture
 132                    && event.button == button
 133                    && !bounds.contains_point(&event.position)
 134                {
 135                    handler(view, event, cx);
 136                }
 137            }));
 138        self
 139    }
 140
 141    fn on_mouse_move(
 142        mut self,
 143        handler: impl Fn(&mut Self::ViewState, &MouseMoveEvent, &mut ViewContext<Self::ViewState>)
 144            + Send
 145            + Sync
 146            + 'static,
 147    ) -> Self
 148    where
 149        Self: Sized,
 150    {
 151        self.stateless_interactivity()
 152            .mouse_move_listeners
 153            .push(Arc::new(move |view, event, bounds, phase, cx| {
 154                if phase == DispatchPhase::Bubble && bounds.contains_point(&event.position) {
 155                    handler(view, event, cx);
 156                }
 157            }));
 158        self
 159    }
 160
 161    fn on_scroll_wheel(
 162        mut self,
 163        handler: impl Fn(&mut Self::ViewState, &ScrollWheelEvent, &mut ViewContext<Self::ViewState>)
 164            + Send
 165            + Sync
 166            + 'static,
 167    ) -> Self
 168    where
 169        Self: Sized,
 170    {
 171        self.stateless_interactivity()
 172            .scroll_wheel_listeners
 173            .push(Arc::new(move |view, event, bounds, phase, cx| {
 174                if phase == DispatchPhase::Bubble && bounds.contains_point(&event.position) {
 175                    handler(view, event, cx);
 176                }
 177            }));
 178        self
 179    }
 180
 181    fn context<C>(mut self, context: C) -> Self
 182    where
 183        Self: Sized,
 184        C: TryInto<DispatchContext>,
 185        C::Error: Debug,
 186    {
 187        self.stateless_interactivity().dispatch_context =
 188            context.try_into().expect("invalid dispatch context");
 189        self
 190    }
 191
 192    fn on_action<A: 'static>(
 193        mut self,
 194        listener: impl Fn(&mut Self::ViewState, &A, DispatchPhase, &mut ViewContext<Self::ViewState>)
 195            + Send
 196            + Sync
 197            + 'static,
 198    ) -> Self
 199    where
 200        Self: Sized,
 201    {
 202        self.stateless_interactivity().key_listeners.push((
 203            TypeId::of::<A>(),
 204            Arc::new(move |view, event, _, phase, cx| {
 205                let event = event.downcast_ref().unwrap();
 206                listener(view, event, phase, cx);
 207                None
 208            }),
 209        ));
 210        self
 211    }
 212
 213    fn on_key_down(
 214        mut self,
 215        listener: impl Fn(
 216                &mut Self::ViewState,
 217                &KeyDownEvent,
 218                DispatchPhase,
 219                &mut ViewContext<Self::ViewState>,
 220            ) + Send
 221            + Sync
 222            + 'static,
 223    ) -> Self
 224    where
 225        Self: Sized,
 226    {
 227        self.stateless_interactivity().key_listeners.push((
 228            TypeId::of::<KeyDownEvent>(),
 229            Arc::new(move |view, event, _, phase, cx| {
 230                let event = event.downcast_ref().unwrap();
 231                listener(view, event, phase, cx);
 232                None
 233            }),
 234        ));
 235        self
 236    }
 237
 238    fn on_key_up(
 239        mut self,
 240        listener: impl Fn(&mut Self::ViewState, &KeyUpEvent, DispatchPhase, &mut ViewContext<Self::ViewState>)
 241            + Send
 242            + Sync
 243            + 'static,
 244    ) -> Self
 245    where
 246        Self: Sized,
 247    {
 248        self.stateless_interactivity().key_listeners.push((
 249            TypeId::of::<KeyUpEvent>(),
 250            Arc::new(move |view, event, _, phase, cx| {
 251                let event = event.downcast_ref().unwrap();
 252                listener(view, event, phase, cx);
 253                None
 254            }),
 255        ));
 256        self
 257    }
 258}
 259
 260pub trait StatefulInteractive: StatelessInteractive {
 261    fn stateful_interaction(&mut self) -> &mut StatefulInteraction<Self::ViewState>;
 262
 263    fn active(mut self, f: impl FnOnce(StyleRefinement) -> StyleRefinement) -> Self
 264    where
 265        Self: Sized,
 266    {
 267        self.stateful_interaction().active_style = f(StyleRefinement::default());
 268        self
 269    }
 270
 271    fn group_active(
 272        mut self,
 273        group_name: impl Into<SharedString>,
 274        f: impl FnOnce(StyleRefinement) -> StyleRefinement,
 275    ) -> Self
 276    where
 277        Self: Sized,
 278    {
 279        self.stateful_interaction().group_active_style = Some(GroupStyle {
 280            group: group_name.into(),
 281            style: f(StyleRefinement::default()),
 282        });
 283        self
 284    }
 285
 286    fn on_click(
 287        mut self,
 288        listener: impl Fn(&mut Self::ViewState, &ClickEvent, &mut ViewContext<Self::ViewState>)
 289            + Send
 290            + Sync
 291            + 'static,
 292    ) -> Self
 293    where
 294        Self: Sized,
 295    {
 296        self.stateful_interaction()
 297            .click_listeners
 298            .push(Arc::new(move |view, event, cx| listener(view, event, cx)));
 299        self
 300    }
 301
 302    fn on_drag<S, R, E>(
 303        mut self,
 304        listener: impl Fn(
 305                &mut Self::ViewState,
 306                &mut ViewContext<Self::ViewState>,
 307            ) -> Drag<S, R, Self::ViewState, E>
 308            + Send
 309            + Sync
 310            + 'static,
 311    ) -> Self
 312    where
 313        Self: Sized,
 314        S: 'static + Send + Sync,
 315        R: 'static + Fn(&mut Self::ViewState, &mut ViewContext<Self::ViewState>) -> E + Send + Sync,
 316        E: Element<ViewState = Self::ViewState>,
 317    {
 318        debug_assert!(
 319            self.stateful_interaction().drag_listener.is_none(),
 320            "calling on_drag more than once on the same element is not supported"
 321        );
 322        self.stateful_interaction().drag_listener = Some(Arc::new(move |view_state, cx| {
 323            let drag = listener(view_state, cx);
 324            let view_handle = cx.handle().upgrade().unwrap();
 325            let drag_handle_view = view(view_handle, move |view_state, cx| {
 326                (drag.render_drag_handle)(view_state, cx)
 327            })
 328            .into_any();
 329            AnyDrag {
 330                drag_handle_view,
 331                state: Box::new(drag.state),
 332                state_type: TypeId::of::<S>(),
 333            }
 334        }));
 335        self
 336    }
 337}
 338
 339pub trait ElementInteraction<V: 'static + Send + Sync>: 'static + Send + Sync {
 340    fn as_stateless(&self) -> &StatelessInteraction<V>;
 341    fn as_stateless_mut(&mut self) -> &mut StatelessInteraction<V>;
 342    fn as_stateful(&self) -> Option<&StatefulInteraction<V>>;
 343    fn as_stateful_mut(&mut self) -> Option<&mut StatefulInteraction<V>>;
 344
 345    fn initialize<R>(
 346        &mut self,
 347        cx: &mut ViewContext<V>,
 348        f: impl FnOnce(&mut ViewContext<V>) -> R,
 349    ) -> R {
 350        if let Some(stateful) = self.as_stateful_mut() {
 351            cx.with_element_id(stateful.id.clone(), |global_id, cx| {
 352                stateful.key_listeners.push((
 353                    TypeId::of::<KeyDownEvent>(),
 354                    Arc::new(move |_, key_down, context, phase, cx| {
 355                        if phase == DispatchPhase::Bubble {
 356                            let key_down = key_down.downcast_ref::<KeyDownEvent>().unwrap();
 357                            if let KeyMatch::Some(action) =
 358                                cx.match_keystroke(&global_id, &key_down.keystroke, context)
 359                            {
 360                                return Some(action);
 361                            }
 362                        }
 363
 364                        None
 365                    }),
 366                ));
 367                let result = stateful.stateless.initialize(cx, f);
 368                stateful.key_listeners.pop();
 369                result
 370            })
 371        } else {
 372            let stateless = self.as_stateless();
 373            cx.with_key_dispatch_context(stateless.dispatch_context.clone(), |cx| {
 374                cx.with_key_listeners(&stateless.key_listeners, f)
 375            })
 376        }
 377    }
 378
 379    fn refine_style(
 380        &self,
 381        style: &mut Style,
 382        bounds: Bounds<Pixels>,
 383        element_state: &InteractiveElementState,
 384        cx: &mut ViewContext<V>,
 385    ) {
 386        let mouse_position = cx.mouse_position();
 387        let stateless = self.as_stateless();
 388        if let Some(group_hover) = stateless.group_hover_style.as_ref() {
 389            if let Some(group_bounds) = GroupBounds::get(&group_hover.group, cx) {
 390                if group_bounds.contains_point(&mouse_position) {
 391                    style.refine(&group_hover.style);
 392                }
 393            }
 394        }
 395        if bounds.contains_point(&mouse_position) {
 396            style.refine(&stateless.hover_style);
 397        }
 398
 399        if let Some(stateful) = self.as_stateful() {
 400            let active_state = element_state.active_state.lock();
 401            if active_state.group {
 402                if let Some(group_style) = stateful.group_active_style.as_ref() {
 403                    style.refine(&group_style.style);
 404                }
 405            }
 406            if active_state.element {
 407                style.refine(&stateful.active_style);
 408            }
 409        }
 410    }
 411
 412    fn paint(
 413        &mut self,
 414        bounds: Bounds<Pixels>,
 415        content_size: Size<Pixels>,
 416        overflow: Point<Overflow>,
 417        element_state: &mut InteractiveElementState,
 418        cx: &mut ViewContext<V>,
 419    ) {
 420        let stateless = self.as_stateless();
 421        for listener in stateless.mouse_down_listeners.iter().cloned() {
 422            cx.on_mouse_event(move |state, event: &MouseDownEvent, phase, cx| {
 423                listener(state, event, &bounds, phase, cx);
 424            })
 425        }
 426
 427        for listener in stateless.mouse_up_listeners.iter().cloned() {
 428            cx.on_mouse_event(move |state, event: &MouseUpEvent, phase, cx| {
 429                listener(state, event, &bounds, phase, cx);
 430            })
 431        }
 432
 433        for listener in stateless.mouse_move_listeners.iter().cloned() {
 434            cx.on_mouse_event(move |state, event: &MouseMoveEvent, phase, cx| {
 435                listener(state, event, &bounds, phase, cx);
 436            })
 437        }
 438
 439        for listener in stateless.scroll_wheel_listeners.iter().cloned() {
 440            cx.on_mouse_event(move |state, event: &ScrollWheelEvent, phase, cx| {
 441                listener(state, event, &bounds, phase, cx);
 442            })
 443        }
 444
 445        let hover_group_bounds = stateless
 446            .group_hover_style
 447            .as_ref()
 448            .and_then(|group_hover| GroupBounds::get(&group_hover.group, cx));
 449
 450        if let Some(group_bounds) = hover_group_bounds {
 451            paint_hover_listener(group_bounds, cx);
 452        }
 453
 454        if stateless.hover_style.is_some() {
 455            paint_hover_listener(bounds, cx);
 456        }
 457
 458        if let Some(stateful) = self.as_stateful() {
 459            let click_listeners = stateful.click_listeners.clone();
 460            let drag_listener = stateful.drag_listener.clone();
 461
 462            if !click_listeners.is_empty() || drag_listener.is_some() {
 463                let pending_mouse_down = element_state.pending_mouse_down.clone();
 464                let mouse_down = pending_mouse_down.lock().clone();
 465                if let Some(mouse_down) = mouse_down {
 466                    if let Some(drag_listener) = drag_listener {
 467                        cx.on_mouse_event(move |view_state, event: &MouseMoveEvent, phase, cx| {
 468                            if cx.active_drag.is_some() {
 469                                if phase == DispatchPhase::Capture {
 470                                    cx.notify();
 471                                }
 472                            } else if phase == DispatchPhase::Bubble
 473                                && bounds.contains_point(&event.position)
 474                            {
 475                                let any_drag = drag_listener(view_state, cx);
 476                                cx.start_drag(any_drag);
 477                                cx.stop_propagation();
 478                            }
 479                        });
 480                    }
 481
 482                    cx.on_mouse_event(move |view_state, event: &MouseUpEvent, phase, cx| {
 483                        if phase == DispatchPhase::Bubble && bounds.contains_point(&event.position)
 484                        {
 485                            let mouse_click = ClickEvent {
 486                                down: mouse_down.clone(),
 487                                up: event.clone(),
 488                            };
 489                            for listener in &click_listeners {
 490                                listener(view_state, &mouse_click, cx);
 491                            }
 492                        }
 493
 494                        if cx.active_drag.is_some() {
 495                            cx.end_drag();
 496                        }
 497                        *pending_mouse_down.lock() = None;
 498                    });
 499                } else {
 500                    cx.on_mouse_event(move |_state, event: &MouseDownEvent, phase, _cx| {
 501                        if phase == DispatchPhase::Bubble && bounds.contains_point(&event.position)
 502                        {
 503                            *pending_mouse_down.lock() = Some(event.clone());
 504                        }
 505                    });
 506                }
 507            }
 508
 509            let active_state = element_state.active_state.clone();
 510            if active_state.lock().is_none() {
 511                let active_group_bounds = stateful
 512                    .group_active_style
 513                    .as_ref()
 514                    .and_then(|group_active| GroupBounds::get(&group_active.group, cx));
 515                cx.on_mouse_event(move |_view, down: &MouseDownEvent, phase, cx| {
 516                    if phase == DispatchPhase::Bubble {
 517                        let group = active_group_bounds
 518                            .map_or(false, |bounds| bounds.contains_point(&down.position));
 519                        let element = bounds.contains_point(&down.position);
 520                        if group || element {
 521                            *active_state.lock() = ActiveState { group, element };
 522                            cx.notify();
 523                        }
 524                    }
 525                });
 526            } else {
 527                cx.on_mouse_event(move |_, _: &MouseUpEvent, phase, cx| {
 528                    if phase == DispatchPhase::Capture {
 529                        *active_state.lock() = ActiveState::default();
 530                        cx.notify();
 531                    }
 532                });
 533            }
 534
 535            if overflow.x == Overflow::Scroll || overflow.y == Overflow::Scroll {
 536                let scroll_offset = element_state
 537                    .scroll_offset
 538                    .get_or_insert_with(Arc::default)
 539                    .clone();
 540                let line_height = cx.line_height();
 541                let scroll_max = (content_size - bounds.size).max(&Size::default());
 542
 543                cx.on_mouse_event(move |_, event: &ScrollWheelEvent, phase, cx| {
 544                    if phase == DispatchPhase::Bubble && bounds.contains_point(&event.position) {
 545                        let mut scroll_offset = scroll_offset.lock();
 546                        let old_scroll_offset = *scroll_offset;
 547                        let delta = event.delta.pixel_delta(line_height);
 548
 549                        if overflow.x == Overflow::Scroll {
 550                            scroll_offset.x =
 551                                (scroll_offset.x + delta.x).clamp(-scroll_max.width, px(0.));
 552                        }
 553
 554                        if overflow.y == Overflow::Scroll {
 555                            scroll_offset.y =
 556                                (scroll_offset.y + delta.y).clamp(-scroll_max.height, px(0.));
 557                        }
 558
 559                        if *scroll_offset != old_scroll_offset {
 560                            cx.notify();
 561                            cx.stop_propagation();
 562                        }
 563                    }
 564                });
 565            }
 566        }
 567    }
 568}
 569
 570fn paint_hover_listener<V>(bounds: Bounds<Pixels>, cx: &mut ViewContext<V>)
 571where
 572    V: 'static + Send + Sync,
 573{
 574    let hovered = bounds.contains_point(&cx.mouse_position());
 575    cx.on_mouse_event(move |_, event: &MouseMoveEvent, phase, cx| {
 576        if phase == DispatchPhase::Capture {
 577            if bounds.contains_point(&event.position) != hovered {
 578                cx.notify();
 579            }
 580        }
 581    });
 582}
 583
 584#[derive(Deref, DerefMut)]
 585pub struct StatefulInteraction<V: 'static + Send + Sync> {
 586    pub id: ElementId,
 587    #[deref]
 588    #[deref_mut]
 589    stateless: StatelessInteraction<V>,
 590    pub click_listeners: SmallVec<[ClickListener<V>; 2]>,
 591    pub(crate) drag_listener: Option<DragListener<V>>,
 592    pub active_style: StyleRefinement,
 593    pub group_active_style: Option<GroupStyle>,
 594}
 595
 596impl<V> ElementInteraction<V> for StatefulInteraction<V>
 597where
 598    V: 'static + Send + Sync,
 599{
 600    fn as_stateful(&self) -> Option<&StatefulInteraction<V>> {
 601        Some(self)
 602    }
 603
 604    fn as_stateful_mut(&mut self) -> Option<&mut StatefulInteraction<V>> {
 605        Some(self)
 606    }
 607
 608    fn as_stateless(&self) -> &StatelessInteraction<V> {
 609        &self.stateless
 610    }
 611
 612    fn as_stateless_mut(&mut self) -> &mut StatelessInteraction<V> {
 613        &mut self.stateless
 614    }
 615}
 616
 617impl<V> From<ElementId> for StatefulInteraction<V>
 618where
 619    V: 'static + Send + Sync,
 620{
 621    fn from(id: ElementId) -> Self {
 622        Self {
 623            id,
 624            stateless: StatelessInteraction::default(),
 625            click_listeners: SmallVec::new(),
 626            drag_listener: None,
 627            active_style: StyleRefinement::default(),
 628            group_active_style: None,
 629        }
 630    }
 631}
 632
 633pub struct StatelessInteraction<V> {
 634    pub dispatch_context: DispatchContext,
 635    pub mouse_down_listeners: SmallVec<[MouseDownListener<V>; 2]>,
 636    pub mouse_up_listeners: SmallVec<[MouseUpListener<V>; 2]>,
 637    pub mouse_move_listeners: SmallVec<[MouseMoveListener<V>; 2]>,
 638    pub scroll_wheel_listeners: SmallVec<[ScrollWheelListener<V>; 2]>,
 639    pub key_listeners: SmallVec<[(TypeId, KeyListener<V>); 32]>,
 640    pub hover_style: StyleRefinement,
 641    pub group_hover_style: Option<GroupStyle>,
 642}
 643
 644impl<V> StatelessInteraction<V>
 645where
 646    V: 'static + Send + Sync,
 647{
 648    pub fn into_stateful(self, id: impl Into<ElementId>) -> StatefulInteraction<V> {
 649        StatefulInteraction {
 650            id: id.into(),
 651            stateless: self,
 652            click_listeners: SmallVec::new(),
 653            drag_listener: None,
 654            active_style: StyleRefinement::default(),
 655            group_active_style: None,
 656        }
 657    }
 658}
 659
 660pub struct GroupStyle {
 661    pub group: SharedString,
 662    pub style: StyleRefinement,
 663}
 664
 665#[derive(Default)]
 666pub struct GroupBounds(HashMap<SharedString, SmallVec<[Bounds<Pixels>; 1]>>);
 667
 668impl GroupBounds {
 669    pub fn get(name: &SharedString, cx: &mut AppContext) -> Option<Bounds<Pixels>> {
 670        cx.default_global_mut::<Self>()
 671            .0
 672            .get(name)
 673            .and_then(|bounds_stack| bounds_stack.last())
 674            .cloned()
 675    }
 676
 677    pub fn push(name: SharedString, bounds: Bounds<Pixels>, cx: &mut AppContext) {
 678        cx.default_global_mut::<Self>()
 679            .0
 680            .entry(name)
 681            .or_default()
 682            .push(bounds);
 683    }
 684
 685    pub fn pop(name: &SharedString, cx: &mut AppContext) {
 686        cx.default_global_mut::<Self>()
 687            .0
 688            .get_mut(name)
 689            .unwrap()
 690            .pop();
 691    }
 692}
 693
 694#[derive(Copy, Clone, Default, Eq, PartialEq)]
 695struct ActiveState {
 696    pub group: bool,
 697    pub element: bool,
 698}
 699
 700impl ActiveState {
 701    pub fn is_none(&self) -> bool {
 702        !self.group && !self.element
 703    }
 704}
 705
 706#[derive(Default)]
 707pub struct InteractiveElementState {
 708    active_state: Arc<Mutex<ActiveState>>,
 709    pending_mouse_down: Arc<Mutex<Option<MouseDownEvent>>>,
 710    scroll_offset: Option<Arc<Mutex<Point<Pixels>>>>,
 711}
 712
 713impl InteractiveElementState {
 714    pub fn scroll_offset(&self) -> Option<Point<Pixels>> {
 715        self.scroll_offset
 716            .as_ref()
 717            .map(|offset| offset.lock().clone())
 718    }
 719}
 720
 721impl<V> Default for StatelessInteraction<V> {
 722    fn default() -> Self {
 723        Self {
 724            dispatch_context: DispatchContext::default(),
 725            mouse_down_listeners: SmallVec::new(),
 726            mouse_up_listeners: SmallVec::new(),
 727            mouse_move_listeners: SmallVec::new(),
 728            scroll_wheel_listeners: SmallVec::new(),
 729            key_listeners: SmallVec::new(),
 730            hover_style: StyleRefinement::default(),
 731            group_hover_style: None,
 732        }
 733    }
 734}
 735
 736impl<V> ElementInteraction<V> for StatelessInteraction<V>
 737where
 738    V: 'static + Send + Sync,
 739{
 740    fn as_stateful(&self) -> Option<&StatefulInteraction<V>> {
 741        None
 742    }
 743
 744    fn as_stateful_mut(&mut self) -> Option<&mut StatefulInteraction<V>> {
 745        None
 746    }
 747
 748    fn as_stateless(&self) -> &StatelessInteraction<V> {
 749        self
 750    }
 751
 752    fn as_stateless_mut(&mut self) -> &mut StatelessInteraction<V> {
 753        self
 754    }
 755}
 756
 757#[derive(Clone, Debug, Eq, PartialEq)]
 758pub struct KeyDownEvent {
 759    pub keystroke: Keystroke,
 760    pub is_held: bool,
 761}
 762
 763#[derive(Clone, Debug)]
 764pub struct KeyUpEvent {
 765    pub keystroke: Keystroke,
 766}
 767
 768#[derive(Clone, Debug, Default)]
 769pub struct ModifiersChangedEvent {
 770    pub modifiers: Modifiers,
 771}
 772
 773impl Deref for ModifiersChangedEvent {
 774    type Target = Modifiers;
 775
 776    fn deref(&self) -> &Self::Target {
 777        &self.modifiers
 778    }
 779}
 780
 781/// The phase of a touch motion event.
 782/// Based on the winit enum of the same name.
 783#[derive(Clone, Copy, Debug)]
 784pub enum TouchPhase {
 785    Started,
 786    Moved,
 787    Ended,
 788}
 789
 790#[derive(Clone, Debug, Default)]
 791pub struct MouseDownEvent {
 792    pub button: MouseButton,
 793    pub position: Point<Pixels>,
 794    pub modifiers: Modifiers,
 795    pub click_count: usize,
 796}
 797
 798#[derive(Clone, Debug, Default)]
 799pub struct MouseUpEvent {
 800    pub button: MouseButton,
 801    pub position: Point<Pixels>,
 802    pub modifiers: Modifiers,
 803    pub click_count: usize,
 804}
 805
 806#[derive(Clone, Debug, Default)]
 807pub struct ClickEvent {
 808    pub down: MouseDownEvent,
 809    pub up: MouseUpEvent,
 810}
 811
 812pub struct Drag<S, R, V, E>
 813where
 814    S: 'static + Send + Sync,
 815    R: Fn(&mut V, &mut ViewContext<V>) -> E,
 816    V: 'static + Send + Sync,
 817    E: Element<ViewState = V>,
 818{
 819    pub state: S,
 820    pub render_drag_handle: R,
 821    view_type: PhantomData<V>,
 822}
 823
 824impl<S, R, V, E> Drag<S, R, V, E>
 825where
 826    S: 'static + Send + Sync,
 827    R: Fn(&mut V, &mut ViewContext<V>) -> E + Send + Sync,
 828    V: 'static + Send + Sync,
 829    E: Element<ViewState = V>,
 830{
 831    pub fn new(state: S, render_drag_handle: R) -> Self {
 832        Drag {
 833            state,
 834            render_drag_handle,
 835            view_type: PhantomData,
 836        }
 837    }
 838}
 839
 840#[derive(Hash, PartialEq, Eq, Copy, Clone, Debug)]
 841pub enum MouseButton {
 842    Left,
 843    Right,
 844    Middle,
 845    Navigate(NavigationDirection),
 846}
 847
 848impl MouseButton {
 849    pub fn all() -> Vec<Self> {
 850        vec![
 851            MouseButton::Left,
 852            MouseButton::Right,
 853            MouseButton::Middle,
 854            MouseButton::Navigate(NavigationDirection::Back),
 855            MouseButton::Navigate(NavigationDirection::Forward),
 856        ]
 857    }
 858}
 859
 860impl Default for MouseButton {
 861    fn default() -> Self {
 862        Self::Left
 863    }
 864}
 865
 866#[derive(Hash, PartialEq, Eq, Copy, Clone, Debug)]
 867pub enum NavigationDirection {
 868    Back,
 869    Forward,
 870}
 871
 872impl Default for NavigationDirection {
 873    fn default() -> Self {
 874        Self::Back
 875    }
 876}
 877
 878#[derive(Clone, Debug, Default)]
 879pub struct MouseMoveEvent {
 880    pub position: Point<Pixels>,
 881    pub pressed_button: Option<MouseButton>,
 882    pub modifiers: Modifiers,
 883}
 884
 885#[derive(Clone, Debug)]
 886pub struct ScrollWheelEvent {
 887    pub position: Point<Pixels>,
 888    pub delta: ScrollDelta,
 889    pub modifiers: Modifiers,
 890    pub touch_phase: TouchPhase,
 891}
 892
 893impl Deref for ScrollWheelEvent {
 894    type Target = Modifiers;
 895
 896    fn deref(&self) -> &Self::Target {
 897        &self.modifiers
 898    }
 899}
 900
 901#[derive(Clone, Copy, Debug)]
 902pub enum ScrollDelta {
 903    Pixels(Point<Pixels>),
 904    Lines(Point<f32>),
 905}
 906
 907impl Default for ScrollDelta {
 908    fn default() -> Self {
 909        Self::Lines(Default::default())
 910    }
 911}
 912
 913impl ScrollDelta {
 914    pub fn precise(&self) -> bool {
 915        match self {
 916            ScrollDelta::Pixels(_) => true,
 917            ScrollDelta::Lines(_) => false,
 918        }
 919    }
 920
 921    pub fn pixel_delta(&self, line_height: Pixels) -> Point<Pixels> {
 922        match self {
 923            ScrollDelta::Pixels(delta) => *delta,
 924            ScrollDelta::Lines(delta) => point(line_height * delta.x, line_height * delta.y),
 925        }
 926    }
 927}
 928
 929#[derive(Clone, Debug, Default)]
 930pub struct MouseExitEvent {
 931    pub position: Point<Pixels>,
 932    pub pressed_button: Option<MouseButton>,
 933    pub modifiers: Modifiers,
 934}
 935
 936impl Deref for MouseExitEvent {
 937    type Target = Modifiers;
 938
 939    fn deref(&self) -> &Self::Target {
 940        &self.modifiers
 941    }
 942}
 943
 944#[derive(Clone, Debug)]
 945pub enum InputEvent {
 946    KeyDown(KeyDownEvent),
 947    KeyUp(KeyUpEvent),
 948    ModifiersChanged(ModifiersChangedEvent),
 949    MouseDown(MouseDownEvent),
 950    MouseUp(MouseUpEvent),
 951    MouseMoved(MouseMoveEvent),
 952    MouseExited(MouseExitEvent),
 953    ScrollWheel(ScrollWheelEvent),
 954}
 955
 956impl InputEvent {
 957    pub fn position(&self) -> Option<Point<Pixels>> {
 958        match self {
 959            InputEvent::KeyDown { .. } => None,
 960            InputEvent::KeyUp { .. } => None,
 961            InputEvent::ModifiersChanged { .. } => None,
 962            InputEvent::MouseDown(event) => Some(event.position),
 963            InputEvent::MouseUp(event) => Some(event.position),
 964            InputEvent::MouseMoved(event) => Some(event.position),
 965            InputEvent::MouseExited(event) => Some(event.position),
 966            InputEvent::ScrollWheel(event) => Some(event.position),
 967        }
 968    }
 969
 970    pub fn mouse_event<'a>(&'a self) -> Option<&'a dyn Any> {
 971        match self {
 972            InputEvent::KeyDown { .. } => None,
 973            InputEvent::KeyUp { .. } => None,
 974            InputEvent::ModifiersChanged { .. } => None,
 975            InputEvent::MouseDown(event) => Some(event),
 976            InputEvent::MouseUp(event) => Some(event),
 977            InputEvent::MouseMoved(event) => Some(event),
 978            InputEvent::MouseExited(event) => Some(event),
 979            InputEvent::ScrollWheel(event) => Some(event),
 980        }
 981    }
 982
 983    pub fn keyboard_event<'a>(&'a self) -> Option<&'a dyn Any> {
 984        match self {
 985            InputEvent::KeyDown(event) => Some(event),
 986            InputEvent::KeyUp(event) => Some(event),
 987            InputEvent::ModifiersChanged(event) => Some(event),
 988            InputEvent::MouseDown(_) => None,
 989            InputEvent::MouseUp(_) => None,
 990            InputEvent::MouseMoved(_) => None,
 991            InputEvent::MouseExited(_) => None,
 992            InputEvent::ScrollWheel(_) => None,
 993        }
 994    }
 995}
 996
 997pub struct FocusEvent {
 998    pub blurred: Option<FocusHandle>,
 999    pub focused: Option<FocusHandle>,
1000}
1001
1002pub type MouseDownListener<V> = Arc<
1003    dyn Fn(&mut V, &MouseDownEvent, &Bounds<Pixels>, DispatchPhase, &mut ViewContext<V>)
1004        + Send
1005        + Sync
1006        + 'static,
1007>;
1008pub type MouseUpListener<V> = Arc<
1009    dyn Fn(&mut V, &MouseUpEvent, &Bounds<Pixels>, DispatchPhase, &mut ViewContext<V>)
1010        + Send
1011        + Sync
1012        + 'static,
1013>;
1014
1015pub type MouseMoveListener<V> = Arc<
1016    dyn Fn(&mut V, &MouseMoveEvent, &Bounds<Pixels>, DispatchPhase, &mut ViewContext<V>)
1017        + Send
1018        + Sync
1019        + 'static,
1020>;
1021
1022pub type ScrollWheelListener<V> = Arc<
1023    dyn Fn(&mut V, &ScrollWheelEvent, &Bounds<Pixels>, DispatchPhase, &mut ViewContext<V>)
1024        + Send
1025        + Sync
1026        + 'static,
1027>;
1028
1029pub type ClickListener<V> =
1030    Arc<dyn Fn(&mut V, &ClickEvent, &mut ViewContext<V>) + Send + Sync + 'static>;
1031
1032pub(crate) type DragListener<V> =
1033    Arc<dyn Fn(&mut V, &mut ViewContext<V>) -> AnyDrag + Send + Sync + 'static>;
1034
1035pub type KeyListener<V> = Arc<
1036    dyn Fn(
1037            &mut V,
1038            &dyn Any,
1039            &[&DispatchContext],
1040            DispatchPhase,
1041            &mut ViewContext<V>,
1042        ) -> Option<Box<dyn Action>>
1043        + Send
1044        + Sync
1045        + 'static,
1046>;