window.rs

   1use crate::{
   2    key_dispatch::DispatchActionListener, px, size, Action, AnyDrag, AnyView, AppContext,
   3    AsyncWindowContext, AvailableSpace, Bounds, BoxShadow, Context, Corners, CursorStyle,
   4    DevicePixels, DispatchNodeId, DispatchTree, DisplayId, Edges, Effect, Entity, EntityId,
   5    EventEmitter, FileDropEvent, Flatten, FocusEvent, FontId, GlobalElementId, GlyphId, Hsla,
   6    ImageData, InputEvent, IsZero, KeyBinding, KeyContext, KeyDownEvent, KeystrokeEvent, LayoutId,
   7    Model, ModelContext, Modifiers, MonochromeSprite, MouseButton, MouseMoveEvent, MouseUpEvent,
   8    Path, Pixels, PlatformAtlas, PlatformDisplay, PlatformInputHandler, PlatformWindow, Point,
   9    PolychromeSprite, PromptLevel, Quad, Render, RenderGlyphParams, RenderImageParams,
  10    RenderSvgParams, ScaledPixels, Scene, SceneBuilder, Shadow, SharedString, Size, Style,
  11    SubscriberSet, Subscription, Surface, TaffyLayoutEngine, Task, Underline, UnderlineStyle, View,
  12    VisualContext, WeakView, WindowBounds, WindowOptions, SUBPIXEL_VARIANTS,
  13};
  14use anyhow::{anyhow, Context as _, Result};
  15use collections::HashMap;
  16use derive_more::{Deref, DerefMut};
  17use futures::{
  18    channel::{mpsc, oneshot},
  19    StreamExt,
  20};
  21use media::core_video::CVImageBuffer;
  22use parking_lot::RwLock;
  23use slotmap::SlotMap;
  24use smallvec::SmallVec;
  25use std::{
  26    any::{Any, TypeId},
  27    borrow::{Borrow, BorrowMut, Cow},
  28    fmt::Debug,
  29    future::Future,
  30    hash::{Hash, Hasher},
  31    marker::PhantomData,
  32    mem,
  33    rc::Rc,
  34    sync::{
  35        atomic::{AtomicUsize, Ordering::SeqCst},
  36        Arc,
  37    },
  38};
  39use util::ResultExt;
  40
  41const ACTIVE_DRAG_Z_INDEX: u32 = 1;
  42
  43/// A global stacking order, which is created by stacking successive z-index values.
  44/// Each z-index will always be interpreted in the context of its parent z-index.
  45#[derive(Deref, DerefMut, Ord, PartialOrd, Eq, PartialEq, Clone, Default, Debug)]
  46pub struct StackingOrder(pub(crate) SmallVec<[u32; 16]>);
  47
  48/// Represents the two different phases when dispatching events.
  49#[derive(Default, Copy, Clone, Debug, Eq, PartialEq)]
  50pub enum DispatchPhase {
  51    /// After the capture phase comes the bubble phase, in which mouse event listeners are
  52    /// invoked front to back and keyboard event listeners are invoked from the focused element
  53    /// to the root of the element tree. This is the phase you'll most commonly want to use when
  54    /// registering event listeners.
  55    #[default]
  56    Bubble,
  57    /// During the initial capture phase, mouse event listeners are invoked back to front, and keyboard
  58    /// listeners are invoked from the root of the tree downward toward the focused element. This phase
  59    /// is used for special purposes such as clearing the "pressed" state for click events. If
  60    /// you stop event propagation during this phase, you need to know what you're doing. Handlers
  61    /// outside of the immediate region may rely on detecting non-local events during this phase.
  62    Capture,
  63}
  64
  65impl DispatchPhase {
  66    pub fn bubble(self) -> bool {
  67        self == DispatchPhase::Bubble
  68    }
  69
  70    pub fn capture(self) -> bool {
  71        self == DispatchPhase::Capture
  72    }
  73}
  74
  75type AnyObserver = Box<dyn FnMut(&mut WindowContext) -> bool + 'static>;
  76type AnyMouseListener = Box<dyn FnMut(&dyn Any, DispatchPhase, &mut WindowContext) + 'static>;
  77type AnyFocusListener = Box<dyn Fn(&FocusEvent, &mut WindowContext) + 'static>;
  78type AnyWindowFocusListener = Box<dyn FnMut(&FocusEvent, &mut WindowContext) -> bool + 'static>;
  79
  80slotmap::new_key_type! { pub struct FocusId; }
  81
  82impl FocusId {
  83    /// Obtains whether the element associated with this handle is currently focused.
  84    pub fn is_focused(&self, cx: &WindowContext) -> bool {
  85        cx.window.focus == Some(*self)
  86    }
  87
  88    /// Obtains whether the element associated with this handle contains the focused
  89    /// element or is itself focused.
  90    pub fn contains_focused(&self, cx: &WindowContext) -> bool {
  91        cx.focused()
  92            .map_or(false, |focused| self.contains(focused.id, cx))
  93    }
  94
  95    /// Obtains whether the element associated with this handle is contained within the
  96    /// focused element or is itself focused.
  97    pub fn within_focused(&self, cx: &WindowContext) -> bool {
  98        let focused = cx.focused();
  99        focused.map_or(false, |focused| focused.id.contains(*self, cx))
 100    }
 101
 102    /// Obtains whether this handle contains the given handle in the most recently rendered frame.
 103    pub(crate) fn contains(&self, other: Self, cx: &WindowContext) -> bool {
 104        cx.window
 105            .rendered_frame
 106            .dispatch_tree
 107            .focus_contains(*self, other)
 108    }
 109}
 110
 111/// A handle which can be used to track and manipulate the focused element in a window.
 112pub struct FocusHandle {
 113    pub(crate) id: FocusId,
 114    handles: Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>,
 115}
 116
 117impl std::fmt::Debug for FocusHandle {
 118    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 119        f.write_fmt(format_args!("FocusHandle({:?})", self.id))
 120    }
 121}
 122
 123impl FocusHandle {
 124    pub(crate) fn new(handles: &Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>) -> Self {
 125        let id = handles.write().insert(AtomicUsize::new(1));
 126        Self {
 127            id,
 128            handles: handles.clone(),
 129        }
 130    }
 131
 132    pub(crate) fn for_id(
 133        id: FocusId,
 134        handles: &Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>,
 135    ) -> Option<Self> {
 136        let lock = handles.read();
 137        let ref_count = lock.get(id)?;
 138        if ref_count.load(SeqCst) == 0 {
 139            None
 140        } else {
 141            ref_count.fetch_add(1, SeqCst);
 142            Some(Self {
 143                id,
 144                handles: handles.clone(),
 145            })
 146        }
 147    }
 148
 149    /// Moves the focus to the element associated with this handle.
 150    pub fn focus(&self, cx: &mut WindowContext) {
 151        cx.focus(self)
 152    }
 153
 154    /// Obtains whether the element associated with this handle is currently focused.
 155    pub fn is_focused(&self, cx: &WindowContext) -> bool {
 156        self.id.is_focused(cx)
 157    }
 158
 159    /// Obtains whether the element associated with this handle contains the focused
 160    /// element or is itself focused.
 161    pub fn contains_focused(&self, cx: &WindowContext) -> bool {
 162        self.id.contains_focused(cx)
 163    }
 164
 165    /// Obtains whether the element associated with this handle is contained within the
 166    /// focused element or is itself focused.
 167    pub fn within_focused(&self, cx: &WindowContext) -> bool {
 168        self.id.within_focused(cx)
 169    }
 170
 171    /// Obtains whether this handle contains the given handle in the most recently rendered frame.
 172    pub(crate) fn contains(&self, other: &Self, cx: &WindowContext) -> bool {
 173        self.id.contains(other.id, cx)
 174    }
 175}
 176
 177impl Clone for FocusHandle {
 178    fn clone(&self) -> Self {
 179        Self::for_id(self.id, &self.handles).unwrap()
 180    }
 181}
 182
 183impl PartialEq for FocusHandle {
 184    fn eq(&self, other: &Self) -> bool {
 185        self.id == other.id
 186    }
 187}
 188
 189impl Eq for FocusHandle {}
 190
 191impl Drop for FocusHandle {
 192    fn drop(&mut self) {
 193        self.handles
 194            .read()
 195            .get(self.id)
 196            .unwrap()
 197            .fetch_sub(1, SeqCst);
 198    }
 199}
 200
 201/// FocusableView allows users of your view to easily
 202/// focus it (using cx.focus_view(view))
 203pub trait FocusableView: 'static + Render {
 204    fn focus_handle(&self, cx: &AppContext) -> FocusHandle;
 205}
 206
 207/// ManagedView is a view (like a Modal, Popover, Menu, etc.)
 208/// where the lifecycle of the view is handled by another view.
 209pub trait ManagedView: FocusableView + EventEmitter<DismissEvent> {}
 210
 211impl<M: FocusableView + EventEmitter<DismissEvent>> ManagedView for M {}
 212
 213pub struct DismissEvent;
 214
 215// Holds the state for a specific window.
 216pub struct Window {
 217    pub(crate) handle: AnyWindowHandle,
 218    pub(crate) removed: bool,
 219    pub(crate) platform_window: Box<dyn PlatformWindow>,
 220    display_id: DisplayId,
 221    sprite_atlas: Arc<dyn PlatformAtlas>,
 222    rem_size: Pixels,
 223    viewport_size: Size<Pixels>,
 224    layout_engine: Option<TaffyLayoutEngine>,
 225    pub(crate) root_view: Option<AnyView>,
 226    pub(crate) element_id_stack: GlobalElementId,
 227    pub(crate) rendered_frame: Frame,
 228    pub(crate) next_frame: Frame,
 229    pub(crate) focus_handles: Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>,
 230    pub(crate) focus_listeners: SubscriberSet<(), AnyWindowFocusListener>,
 231    default_prevented: bool,
 232    mouse_position: Point<Pixels>,
 233    requested_cursor_style: Option<CursorStyle>,
 234    scale_factor: f32,
 235    bounds: WindowBounds,
 236    bounds_observers: SubscriberSet<(), AnyObserver>,
 237    active: bool,
 238    pub(crate) dirty: bool,
 239    activation_observers: SubscriberSet<(), AnyObserver>,
 240    pub(crate) last_blur: Option<Option<FocusId>>,
 241    pub(crate) focus: Option<FocusId>,
 242}
 243
 244pub(crate) struct ElementStateBox {
 245    inner: Box<dyn Any>,
 246    #[cfg(debug_assertions)]
 247    type_name: &'static str,
 248}
 249
 250// #[derive(Default)]
 251pub(crate) struct Frame {
 252    pub(crate) element_states: HashMap<GlobalElementId, ElementStateBox>,
 253    mouse_listeners: HashMap<TypeId, Vec<(StackingOrder, AnyMouseListener)>>,
 254    pub(crate) dispatch_tree: DispatchTree,
 255    pub(crate) focus_listeners: Vec<AnyFocusListener>,
 256    pub(crate) scene_builder: SceneBuilder,
 257    pub(crate) depth_map: Vec<(StackingOrder, Bounds<Pixels>)>,
 258    pub(crate) z_index_stack: StackingOrder,
 259    content_mask_stack: Vec<ContentMask<Pixels>>,
 260    element_offset_stack: Vec<Point<Pixels>>,
 261}
 262
 263impl Frame {
 264    fn new(dispatch_tree: DispatchTree) -> Self {
 265        Frame {
 266            element_states: HashMap::default(),
 267            mouse_listeners: HashMap::default(),
 268            dispatch_tree,
 269            focus_listeners: Vec::new(),
 270            scene_builder: SceneBuilder::default(),
 271            z_index_stack: StackingOrder::default(),
 272            depth_map: Default::default(),
 273            content_mask_stack: Vec::new(),
 274            element_offset_stack: Vec::new(),
 275        }
 276    }
 277
 278    fn clear(&mut self) {
 279        self.element_states.clear();
 280        self.mouse_listeners.values_mut().for_each(Vec::clear);
 281        self.focus_listeners.clear();
 282        self.dispatch_tree.clear();
 283        self.depth_map.clear();
 284    }
 285}
 286
 287impl Window {
 288    pub(crate) fn new(
 289        handle: AnyWindowHandle,
 290        options: WindowOptions,
 291        cx: &mut AppContext,
 292    ) -> Self {
 293        let platform_window = cx.platform.open_window(
 294            handle,
 295            options,
 296            Box::new({
 297                let mut cx = cx.to_async();
 298                move || handle.update(&mut cx, |_, cx| cx.draw())
 299            }),
 300        );
 301        let display_id = platform_window.display().id();
 302        let sprite_atlas = platform_window.sprite_atlas();
 303        let mouse_position = platform_window.mouse_position();
 304        let content_size = platform_window.content_size();
 305        let scale_factor = platform_window.scale_factor();
 306        let bounds = platform_window.bounds();
 307
 308        platform_window.on_resize(Box::new({
 309            let mut cx = cx.to_async();
 310            move |_, _| {
 311                handle
 312                    .update(&mut cx, |_, cx| cx.window_bounds_changed())
 313                    .log_err();
 314            }
 315        }));
 316        platform_window.on_moved(Box::new({
 317            let mut cx = cx.to_async();
 318            move || {
 319                handle
 320                    .update(&mut cx, |_, cx| cx.window_bounds_changed())
 321                    .log_err();
 322            }
 323        }));
 324        platform_window.on_active_status_change(Box::new({
 325            let mut cx = cx.to_async();
 326            move |active| {
 327                handle
 328                    .update(&mut cx, |_, cx| {
 329                        cx.window.active = active;
 330                        cx.window
 331                            .activation_observers
 332                            .clone()
 333                            .retain(&(), |callback| callback(cx));
 334                    })
 335                    .log_err();
 336            }
 337        }));
 338
 339        platform_window.on_input({
 340            let mut cx = cx.to_async();
 341            Box::new(move |event| {
 342                handle
 343                    .update(&mut cx, |_, cx| cx.dispatch_event(event))
 344                    .log_err()
 345                    .unwrap_or(false)
 346            })
 347        });
 348
 349        Window {
 350            handle,
 351            removed: false,
 352            platform_window,
 353            display_id,
 354            sprite_atlas,
 355            rem_size: px(16.),
 356            viewport_size: content_size,
 357            layout_engine: Some(TaffyLayoutEngine::new()),
 358            root_view: None,
 359            element_id_stack: GlobalElementId::default(),
 360            rendered_frame: Frame::new(DispatchTree::new(cx.keymap.clone(), cx.actions.clone())),
 361            next_frame: Frame::new(DispatchTree::new(cx.keymap.clone(), cx.actions.clone())),
 362            focus_handles: Arc::new(RwLock::new(SlotMap::with_key())),
 363            focus_listeners: SubscriberSet::new(),
 364            default_prevented: true,
 365            mouse_position,
 366            requested_cursor_style: None,
 367            scale_factor,
 368            bounds,
 369            bounds_observers: SubscriberSet::new(),
 370            active: false,
 371            dirty: false,
 372            activation_observers: SubscriberSet::new(),
 373            last_blur: None,
 374            focus: None,
 375        }
 376    }
 377}
 378
 379/// Indicates which region of the window is visible. Content falling outside of this mask will not be
 380/// rendered. Currently, only rectangular content masks are supported, but we give the mask its own type
 381/// to leave room to support more complex shapes in the future.
 382#[derive(Clone, Debug, Default, PartialEq, Eq)]
 383#[repr(C)]
 384pub struct ContentMask<P: Clone + Default + Debug> {
 385    pub bounds: Bounds<P>,
 386}
 387
 388impl ContentMask<Pixels> {
 389    /// Scale the content mask's pixel units by the given scaling factor.
 390    pub fn scale(&self, factor: f32) -> ContentMask<ScaledPixels> {
 391        ContentMask {
 392            bounds: self.bounds.scale(factor),
 393        }
 394    }
 395
 396    /// Intersect the content mask with the given content mask.
 397    pub fn intersect(&self, other: &Self) -> Self {
 398        let bounds = self.bounds.intersect(&other.bounds);
 399        ContentMask { bounds }
 400    }
 401}
 402
 403/// Provides access to application state in the context of a single window. Derefs
 404/// to an `AppContext`, so you can also pass a `WindowContext` to any method that takes
 405/// an `AppContext` and call any `AppContext` methods.
 406pub struct WindowContext<'a> {
 407    pub(crate) app: &'a mut AppContext,
 408    pub(crate) window: &'a mut Window,
 409}
 410
 411impl<'a> WindowContext<'a> {
 412    pub(crate) fn new(app: &'a mut AppContext, window: &'a mut Window) -> Self {
 413        Self { app, window }
 414    }
 415
 416    /// Obtain a handle to the window that belongs to this context.
 417    pub fn window_handle(&self) -> AnyWindowHandle {
 418        self.window.handle
 419    }
 420
 421    /// Mark the window as dirty, scheduling it to be redrawn on the next frame.
 422    pub fn notify(&mut self) {
 423        self.window.dirty = true;
 424    }
 425
 426    /// Close this window.
 427    pub fn remove_window(&mut self) {
 428        self.window.removed = true;
 429    }
 430
 431    /// Obtain a new `FocusHandle`, which allows you to track and manipulate the keyboard focus
 432    /// for elements rendered within this window.
 433    pub fn focus_handle(&mut self) -> FocusHandle {
 434        FocusHandle::new(&self.window.focus_handles)
 435    }
 436
 437    /// Obtain the currently focused `FocusHandle`. If no elements are focused, returns `None`.
 438    pub fn focused(&self) -> Option<FocusHandle> {
 439        self.window
 440            .focus
 441            .and_then(|id| FocusHandle::for_id(id, &self.window.focus_handles))
 442    }
 443
 444    /// Move focus to the element associated with the given `FocusHandle`.
 445    pub fn focus(&mut self, handle: &FocusHandle) {
 446        if self.window.focus == Some(handle.id) {
 447            return;
 448        }
 449
 450        let focus_id = handle.id;
 451
 452        if self.window.last_blur.is_none() {
 453            self.window.last_blur = Some(self.window.focus);
 454        }
 455
 456        self.window.focus = Some(focus_id);
 457        self.window
 458            .rendered_frame
 459            .dispatch_tree
 460            .clear_pending_keystrokes();
 461        self.app.push_effect(Effect::FocusChanged {
 462            window_handle: self.window.handle,
 463            focused: Some(focus_id),
 464        });
 465        self.notify();
 466    }
 467
 468    /// Remove focus from all elements within this context's window.
 469    pub fn blur(&mut self) {
 470        if self.window.last_blur.is_none() {
 471            self.window.last_blur = Some(self.window.focus);
 472        }
 473
 474        self.window.focus = None;
 475        self.app.push_effect(Effect::FocusChanged {
 476            window_handle: self.window.handle,
 477            focused: None,
 478        });
 479        self.notify();
 480    }
 481
 482    pub fn dispatch_action(&mut self, action: Box<dyn Action>) {
 483        let focus_handle = self.focused();
 484
 485        self.defer(move |cx| {
 486            let node_id = focus_handle
 487                .and_then(|handle| {
 488                    cx.window
 489                        .rendered_frame
 490                        .dispatch_tree
 491                        .focusable_node_id(handle.id)
 492                })
 493                .unwrap_or_else(|| cx.window.rendered_frame.dispatch_tree.root_node_id());
 494
 495            cx.propagate_event = true;
 496            cx.dispatch_action_on_node(node_id, action);
 497        })
 498    }
 499
 500    pub(crate) fn dispatch_keystroke_observers(
 501        &mut self,
 502        event: &dyn Any,
 503        action: Option<Box<dyn Action>>,
 504    ) {
 505        let Some(key_down_event) = event.downcast_ref::<KeyDownEvent>() else {
 506            return;
 507        };
 508
 509        self.keystroke_observers
 510            .clone()
 511            .retain(&(), move |callback| {
 512                (callback)(
 513                    &KeystrokeEvent {
 514                        keystroke: key_down_event.keystroke.clone(),
 515                        action: action.as_ref().map(|action| action.boxed_clone()),
 516                    },
 517                    self,
 518                );
 519                true
 520            });
 521    }
 522
 523    /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
 524    /// that are currently on the stack to be returned to the app.
 525    pub fn defer(&mut self, f: impl FnOnce(&mut WindowContext) + 'static) {
 526        let handle = self.window.handle;
 527        self.app.defer(move |cx| {
 528            handle.update(cx, |_, cx| f(cx)).ok();
 529        });
 530    }
 531
 532    pub fn subscribe<Emitter, E, Evt>(
 533        &mut self,
 534        entity: &E,
 535        mut on_event: impl FnMut(E, &Evt, &mut WindowContext<'_>) + 'static,
 536    ) -> Subscription
 537    where
 538        Emitter: EventEmitter<Evt>,
 539        E: Entity<Emitter>,
 540        Evt: 'static,
 541    {
 542        let entity_id = entity.entity_id();
 543        let entity = entity.downgrade();
 544        let window_handle = self.window.handle;
 545        let (subscription, activate) = self.app.event_listeners.insert(
 546            entity_id,
 547            (
 548                TypeId::of::<Evt>(),
 549                Box::new(move |event, cx| {
 550                    window_handle
 551                        .update(cx, |_, cx| {
 552                            if let Some(handle) = E::upgrade_from(&entity) {
 553                                let event = event.downcast_ref().expect("invalid event type");
 554                                on_event(handle, event, cx);
 555                                true
 556                            } else {
 557                                false
 558                            }
 559                        })
 560                        .unwrap_or(false)
 561                }),
 562            ),
 563        );
 564        self.app.defer(move |_| activate());
 565        subscription
 566    }
 567
 568    /// Create an `AsyncWindowContext`, which has a static lifetime and can be held across
 569    /// await points in async code.
 570    pub fn to_async(&self) -> AsyncWindowContext {
 571        AsyncWindowContext::new(self.app.to_async(), self.window.handle)
 572    }
 573
 574    /// Schedule the given closure to be run directly after the current frame is rendered.
 575    pub fn on_next_frame(&mut self, callback: impl FnOnce(&mut WindowContext) + 'static) {
 576        let handle = self.window.handle;
 577        let display_id = self.window.display_id;
 578
 579        if !self.frame_consumers.contains_key(&display_id) {
 580            let (tx, mut rx) = mpsc::unbounded::<()>();
 581            self.platform.set_display_link_output_callback(
 582                display_id,
 583                Box::new(move |_current_time, _output_time| _ = tx.unbounded_send(())),
 584            );
 585
 586            let consumer_task = self.app.spawn(|cx| async move {
 587                while rx.next().await.is_some() {
 588                    cx.update(|cx| {
 589                        for callback in cx
 590                            .next_frame_callbacks
 591                            .get_mut(&display_id)
 592                            .unwrap()
 593                            .drain(..)
 594                            .collect::<SmallVec<[_; 32]>>()
 595                        {
 596                            callback(cx);
 597                        }
 598                    })
 599                    .ok();
 600
 601                    // Flush effects, then stop the display link if no new next_frame_callbacks have been added.
 602
 603                    cx.update(|cx| {
 604                        if cx.next_frame_callbacks.is_empty() {
 605                            cx.platform.stop_display_link(display_id);
 606                        }
 607                    })
 608                    .ok();
 609                }
 610            });
 611            self.frame_consumers.insert(display_id, consumer_task);
 612        }
 613
 614        if self.next_frame_callbacks.is_empty() {
 615            self.platform.start_display_link(display_id);
 616        }
 617
 618        self.next_frame_callbacks
 619            .entry(display_id)
 620            .or_default()
 621            .push(Box::new(move |cx: &mut AppContext| {
 622                cx.update_window(handle, |_root_view, cx| callback(cx)).ok();
 623            }));
 624    }
 625
 626    /// Spawn the future returned by the given closure on the application thread pool.
 627    /// The closure is provided a handle to the current window and an `AsyncWindowContext` for
 628    /// use within your future.
 629    pub fn spawn<Fut, R>(&mut self, f: impl FnOnce(AsyncWindowContext) -> Fut) -> Task<R>
 630    where
 631        R: 'static,
 632        Fut: Future<Output = R> + 'static,
 633    {
 634        self.app
 635            .spawn(|app| f(AsyncWindowContext::new(app, self.window.handle)))
 636    }
 637
 638    /// Update the global of the given type. The given closure is given simultaneous mutable
 639    /// access both to the global and the context.
 640    pub fn update_global<G, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R
 641    where
 642        G: 'static,
 643    {
 644        let mut global = self.app.lease_global::<G>();
 645        let result = f(&mut global, self);
 646        self.app.end_global_lease(global);
 647        result
 648    }
 649
 650    #[must_use]
 651    /// Add a node to the layout tree for the current frame. Takes the `Style` of the element for which
 652    /// layout is being requested, along with the layout ids of any children. This method is called during
 653    /// calls to the `Element::layout` trait method and enables any element to participate in layout.
 654    pub fn request_layout(
 655        &mut self,
 656        style: &Style,
 657        children: impl IntoIterator<Item = LayoutId>,
 658    ) -> LayoutId {
 659        self.app.layout_id_buffer.clear();
 660        self.app.layout_id_buffer.extend(children.into_iter());
 661        let rem_size = self.rem_size();
 662
 663        self.window.layout_engine.as_mut().unwrap().request_layout(
 664            style,
 665            rem_size,
 666            &self.app.layout_id_buffer,
 667        )
 668    }
 669
 670    /// Add a node to the layout tree for the current frame. Instead of taking a `Style` and children,
 671    /// this variant takes a function that is invoked during layout so you can use arbitrary logic to
 672    /// determine the element's size. One place this is used internally is when measuring text.
 673    ///
 674    /// The given closure is invoked at layout time with the known dimensions and available space and
 675    /// returns a `Size`.
 676    pub fn request_measured_layout<
 677        F: FnMut(Size<Option<Pixels>>, Size<AvailableSpace>, &mut WindowContext) -> Size<Pixels>
 678            + 'static,
 679    >(
 680        &mut self,
 681        style: Style,
 682        measure: F,
 683    ) -> LayoutId {
 684        let rem_size = self.rem_size();
 685        self.window
 686            .layout_engine
 687            .as_mut()
 688            .unwrap()
 689            .request_measured_layout(style, rem_size, measure)
 690    }
 691
 692    pub fn compute_layout(&mut self, layout_id: LayoutId, available_space: Size<AvailableSpace>) {
 693        let mut layout_engine = self.window.layout_engine.take().unwrap();
 694        layout_engine.compute_layout(layout_id, available_space, self);
 695        self.window.layout_engine = Some(layout_engine);
 696    }
 697
 698    /// Obtain the bounds computed for the given LayoutId relative to the window. This method should not
 699    /// be invoked until the paint phase begins, and will usually be invoked by GPUI itself automatically
 700    /// in order to pass your element its `Bounds` automatically.
 701    pub fn layout_bounds(&mut self, layout_id: LayoutId) -> Bounds<Pixels> {
 702        let mut bounds = self
 703            .window
 704            .layout_engine
 705            .as_mut()
 706            .unwrap()
 707            .layout_bounds(layout_id)
 708            .map(Into::into);
 709        bounds.origin += self.element_offset();
 710        bounds
 711    }
 712
 713    fn window_bounds_changed(&mut self) {
 714        self.window.scale_factor = self.window.platform_window.scale_factor();
 715        self.window.viewport_size = self.window.platform_window.content_size();
 716        self.window.bounds = self.window.platform_window.bounds();
 717        self.window.display_id = self.window.platform_window.display().id();
 718        self.notify();
 719
 720        self.window
 721            .bounds_observers
 722            .clone()
 723            .retain(&(), |callback| callback(self));
 724    }
 725
 726    pub fn window_bounds(&self) -> WindowBounds {
 727        self.window.bounds
 728    }
 729
 730    pub fn viewport_size(&self) -> Size<Pixels> {
 731        self.window.viewport_size
 732    }
 733
 734    pub fn is_window_active(&self) -> bool {
 735        self.window.active
 736    }
 737
 738    pub fn zoom_window(&self) {
 739        self.window.platform_window.zoom();
 740    }
 741
 742    pub fn set_window_title(&mut self, title: &str) {
 743        self.window.platform_window.set_title(title);
 744    }
 745
 746    pub fn display(&self) -> Option<Rc<dyn PlatformDisplay>> {
 747        self.platform
 748            .displays()
 749            .into_iter()
 750            .find(|display| display.id() == self.window.display_id)
 751    }
 752
 753    pub fn show_character_palette(&self) {
 754        self.window.platform_window.show_character_palette();
 755    }
 756
 757    /// The scale factor of the display associated with the window. For example, it could
 758    /// return 2.0 for a "retina" display, indicating that each logical pixel should actually
 759    /// be rendered as two pixels on screen.
 760    pub fn scale_factor(&self) -> f32 {
 761        self.window.scale_factor
 762    }
 763
 764    /// The size of an em for the base font of the application. Adjusting this value allows the
 765    /// UI to scale, just like zooming a web page.
 766    pub fn rem_size(&self) -> Pixels {
 767        self.window.rem_size
 768    }
 769
 770    /// Sets the size of an em for the base font of the application. Adjusting this value allows the
 771    /// UI to scale, just like zooming a web page.
 772    pub fn set_rem_size(&mut self, rem_size: impl Into<Pixels>) {
 773        self.window.rem_size = rem_size.into();
 774    }
 775
 776    /// The line height associated with the current text style.
 777    pub fn line_height(&self) -> Pixels {
 778        let rem_size = self.rem_size();
 779        let text_style = self.text_style();
 780        text_style
 781            .line_height
 782            .to_pixels(text_style.font_size.into(), rem_size)
 783    }
 784
 785    /// Call to prevent the default action of an event. Currently only used to prevent
 786    /// parent elements from becoming focused on mouse down.
 787    pub fn prevent_default(&mut self) {
 788        self.window.default_prevented = true;
 789    }
 790
 791    /// Obtain whether default has been prevented for the event currently being dispatched.
 792    pub fn default_prevented(&self) -> bool {
 793        self.window.default_prevented
 794    }
 795
 796    /// Register a mouse event listener on the window for the next frame. The type of event
 797    /// is determined by the first parameter of the given listener. When the next frame is rendered
 798    /// the listener will be cleared.
 799    ///
 800    /// This is a fairly low-level method, so prefer using event handlers on elements unless you have
 801    /// a specific need to register a global listener.
 802    pub fn on_mouse_event<Event: 'static>(
 803        &mut self,
 804        handler: impl Fn(&Event, DispatchPhase, &mut WindowContext) + 'static,
 805    ) {
 806        let order = self.window.next_frame.z_index_stack.clone();
 807        self.window
 808            .next_frame
 809            .mouse_listeners
 810            .entry(TypeId::of::<Event>())
 811            .or_default()
 812            .push((
 813                order,
 814                Box::new(move |event: &dyn Any, phase, cx| {
 815                    handler(event.downcast_ref().unwrap(), phase, cx)
 816                }),
 817            ))
 818    }
 819
 820    /// Register a key event listener on the window for the next frame. The type of event
 821    /// is determined by the first parameter of the given listener. When the next frame is rendered
 822    /// the listener will be cleared.
 823    ///
 824    /// This is a fairly low-level method, so prefer using event handlers on elements unless you have
 825    /// a specific need to register a global listener.
 826    pub fn on_key_event<Event: 'static>(
 827        &mut self,
 828        handler: impl Fn(&Event, DispatchPhase, &mut WindowContext) + 'static,
 829    ) {
 830        self.window
 831            .next_frame
 832            .dispatch_tree
 833            .on_key_event(Rc::new(move |event, phase, cx| {
 834                if let Some(event) = event.downcast_ref::<Event>() {
 835                    handler(event, phase, cx)
 836                }
 837            }));
 838    }
 839
 840    /// Register an action listener on the window for the next frame. The type of action
 841    /// is determined by the first parameter of the given listener. When the next frame is rendered
 842    /// the listener will be cleared.
 843    ///
 844    /// This is a fairly low-level method, so prefer using action handlers on elements unless you have
 845    /// a specific need to register a global listener.
 846    pub fn on_action(
 847        &mut self,
 848        action_type: TypeId,
 849        handler: impl Fn(&dyn Any, DispatchPhase, &mut WindowContext) + 'static,
 850    ) {
 851        self.window.next_frame.dispatch_tree.on_action(
 852            action_type,
 853            Rc::new(move |action, phase, cx| handler(action, phase, cx)),
 854        );
 855    }
 856
 857    pub fn is_action_available(&self, action: &dyn Action) -> bool {
 858        let target = self
 859            .focused()
 860            .and_then(|focused_handle| {
 861                self.window
 862                    .rendered_frame
 863                    .dispatch_tree
 864                    .focusable_node_id(focused_handle.id)
 865            })
 866            .unwrap_or_else(|| self.window.rendered_frame.dispatch_tree.root_node_id());
 867        self.window
 868            .rendered_frame
 869            .dispatch_tree
 870            .is_action_available(action, target)
 871    }
 872
 873    /// The position of the mouse relative to the window.
 874    pub fn mouse_position(&self) -> Point<Pixels> {
 875        self.window.mouse_position
 876    }
 877
 878    pub fn set_cursor_style(&mut self, style: CursorStyle) {
 879        self.window.requested_cursor_style = Some(style)
 880    }
 881
 882    /// Called during painting to invoke the given closure in a new stacking context. The given
 883    /// z-index is interpreted relative to the previous call to `stack`.
 884    pub fn with_z_index<R>(&mut self, z_index: u32, f: impl FnOnce(&mut Self) -> R) -> R {
 885        self.window.next_frame.z_index_stack.push(z_index);
 886        let result = f(self);
 887        self.window.next_frame.z_index_stack.pop();
 888        result
 889    }
 890
 891    /// Called during painting to track which z-index is on top at each pixel position
 892    pub fn add_opaque_layer(&mut self, bounds: Bounds<Pixels>) {
 893        let stacking_order = self.window.next_frame.z_index_stack.clone();
 894        let depth_map = &mut self.window.next_frame.depth_map;
 895        match depth_map.binary_search_by(|(level, _)| stacking_order.cmp(&level)) {
 896            Ok(i) | Err(i) => depth_map.insert(i, (stacking_order, bounds)),
 897        }
 898    }
 899
 900    /// Returns true if the top-most opaque layer painted over this point was part of the
 901    /// same layer as the given stacking order.
 902    pub fn was_top_layer(&self, point: &Point<Pixels>, level: &StackingOrder) -> bool {
 903        for (stack, bounds) in self.window.rendered_frame.depth_map.iter() {
 904            if bounds.contains(point) {
 905                return level.starts_with(stack) || stack.starts_with(level);
 906            }
 907        }
 908
 909        false
 910    }
 911
 912    pub fn was_top_layer_under_active_drag(
 913        &self,
 914        point: &Point<Pixels>,
 915        level: &StackingOrder,
 916    ) -> bool {
 917        for (stack, bounds) in self.window.rendered_frame.depth_map.iter() {
 918            if stack.starts_with(&[ACTIVE_DRAG_Z_INDEX]) {
 919                continue;
 920            }
 921            if bounds.contains(point) {
 922                return level.starts_with(stack) || stack.starts_with(level);
 923            }
 924        }
 925
 926        false
 927    }
 928
 929    /// Called during painting to get the current stacking order.
 930    pub fn stacking_order(&self) -> &StackingOrder {
 931        &self.window.next_frame.z_index_stack
 932    }
 933
 934    /// Paint one or more drop shadows into the scene for the next frame at the current z-index.
 935    pub fn paint_shadows(
 936        &mut self,
 937        bounds: Bounds<Pixels>,
 938        corner_radii: Corners<Pixels>,
 939        shadows: &[BoxShadow],
 940    ) {
 941        let scale_factor = self.scale_factor();
 942        let content_mask = self.content_mask();
 943        let window = &mut *self.window;
 944        for shadow in shadows {
 945            let mut shadow_bounds = bounds;
 946            shadow_bounds.origin += shadow.offset;
 947            shadow_bounds.dilate(shadow.spread_radius);
 948            window.next_frame.scene_builder.insert(
 949                &window.next_frame.z_index_stack,
 950                Shadow {
 951                    order: 0,
 952                    bounds: shadow_bounds.scale(scale_factor),
 953                    content_mask: content_mask.scale(scale_factor),
 954                    corner_radii: corner_radii.scale(scale_factor),
 955                    color: shadow.color,
 956                    blur_radius: shadow.blur_radius.scale(scale_factor),
 957                },
 958            );
 959        }
 960    }
 961
 962    /// Paint one or more quads into the scene for the next frame at the current stacking context.
 963    /// Quads are colored rectangular regions with an optional background, border, and corner radius.
 964    pub fn paint_quad(
 965        &mut self,
 966        bounds: Bounds<Pixels>,
 967        corner_radii: Corners<Pixels>,
 968        background: impl Into<Hsla>,
 969        border_widths: Edges<Pixels>,
 970        border_color: impl Into<Hsla>,
 971    ) {
 972        let scale_factor = self.scale_factor();
 973        let content_mask = self.content_mask();
 974
 975        let window = &mut *self.window;
 976        window.next_frame.scene_builder.insert(
 977            &window.next_frame.z_index_stack,
 978            Quad {
 979                order: 0,
 980                bounds: bounds.scale(scale_factor),
 981                content_mask: content_mask.scale(scale_factor),
 982                background: background.into(),
 983                border_color: border_color.into(),
 984                corner_radii: corner_radii.scale(scale_factor),
 985                border_widths: border_widths.scale(scale_factor),
 986            },
 987        );
 988    }
 989
 990    /// Paint the given `Path` into the scene for the next frame at the current z-index.
 991    pub fn paint_path(&mut self, mut path: Path<Pixels>, color: impl Into<Hsla>) {
 992        let scale_factor = self.scale_factor();
 993        let content_mask = self.content_mask();
 994        path.content_mask = content_mask;
 995        path.color = color.into();
 996        let window = &mut *self.window;
 997        window
 998            .next_frame
 999            .scene_builder
1000            .insert(&window.next_frame.z_index_stack, path.scale(scale_factor));
1001    }
1002
1003    /// Paint an underline into the scene for the next frame at the current z-index.
1004    pub fn paint_underline(
1005        &mut self,
1006        origin: Point<Pixels>,
1007        width: Pixels,
1008        style: &UnderlineStyle,
1009    ) {
1010        let scale_factor = self.scale_factor();
1011        let height = if style.wavy {
1012            style.thickness * 3.
1013        } else {
1014            style.thickness
1015        };
1016        let bounds = Bounds {
1017            origin,
1018            size: size(width, height),
1019        };
1020        let content_mask = self.content_mask();
1021        let window = &mut *self.window;
1022        window.next_frame.scene_builder.insert(
1023            &window.next_frame.z_index_stack,
1024            Underline {
1025                order: 0,
1026                bounds: bounds.scale(scale_factor),
1027                content_mask: content_mask.scale(scale_factor),
1028                thickness: style.thickness.scale(scale_factor),
1029                color: style.color.unwrap_or_default(),
1030                wavy: style.wavy,
1031            },
1032        );
1033    }
1034
1035    /// Paint a monochrome (non-emoji) glyph into the scene for the next frame at the current z-index.
1036    /// The y component of the origin is the baseline of the glyph.
1037    pub fn paint_glyph(
1038        &mut self,
1039        origin: Point<Pixels>,
1040        font_id: FontId,
1041        glyph_id: GlyphId,
1042        font_size: Pixels,
1043        color: Hsla,
1044    ) -> Result<()> {
1045        let scale_factor = self.scale_factor();
1046        let glyph_origin = origin.scale(scale_factor);
1047        let subpixel_variant = Point {
1048            x: (glyph_origin.x.0.fract() * SUBPIXEL_VARIANTS as f32).floor() as u8,
1049            y: (glyph_origin.y.0.fract() * SUBPIXEL_VARIANTS as f32).floor() as u8,
1050        };
1051        let params = RenderGlyphParams {
1052            font_id,
1053            glyph_id,
1054            font_size,
1055            subpixel_variant,
1056            scale_factor,
1057            is_emoji: false,
1058        };
1059
1060        let raster_bounds = self.text_system().raster_bounds(&params)?;
1061        if !raster_bounds.is_zero() {
1062            let tile =
1063                self.window
1064                    .sprite_atlas
1065                    .get_or_insert_with(&params.clone().into(), &mut || {
1066                        let (size, bytes) = self.text_system().rasterize_glyph(&params)?;
1067                        Ok((size, Cow::Owned(bytes)))
1068                    })?;
1069            let bounds = Bounds {
1070                origin: glyph_origin.map(|px| px.floor()) + raster_bounds.origin.map(Into::into),
1071                size: tile.bounds.size.map(Into::into),
1072            };
1073            let content_mask = self.content_mask().scale(scale_factor);
1074            let window = &mut *self.window;
1075            window.next_frame.scene_builder.insert(
1076                &window.next_frame.z_index_stack,
1077                MonochromeSprite {
1078                    order: 0,
1079                    bounds,
1080                    content_mask,
1081                    color,
1082                    tile,
1083                },
1084            );
1085        }
1086        Ok(())
1087    }
1088
1089    /// Paint an emoji glyph into the scene for the next frame at the current z-index.
1090    /// The y component of the origin is the baseline of the glyph.
1091    pub fn paint_emoji(
1092        &mut self,
1093        origin: Point<Pixels>,
1094        font_id: FontId,
1095        glyph_id: GlyphId,
1096        font_size: Pixels,
1097    ) -> Result<()> {
1098        let scale_factor = self.scale_factor();
1099        let glyph_origin = origin.scale(scale_factor);
1100        let params = RenderGlyphParams {
1101            font_id,
1102            glyph_id,
1103            font_size,
1104            // We don't render emojis with subpixel variants.
1105            subpixel_variant: Default::default(),
1106            scale_factor,
1107            is_emoji: true,
1108        };
1109
1110        let raster_bounds = self.text_system().raster_bounds(&params)?;
1111        if !raster_bounds.is_zero() {
1112            let tile =
1113                self.window
1114                    .sprite_atlas
1115                    .get_or_insert_with(&params.clone().into(), &mut || {
1116                        let (size, bytes) = self.text_system().rasterize_glyph(&params)?;
1117                        Ok((size, Cow::Owned(bytes)))
1118                    })?;
1119            let bounds = Bounds {
1120                origin: glyph_origin.map(|px| px.floor()) + raster_bounds.origin.map(Into::into),
1121                size: tile.bounds.size.map(Into::into),
1122            };
1123            let content_mask = self.content_mask().scale(scale_factor);
1124            let window = &mut *self.window;
1125
1126            window.next_frame.scene_builder.insert(
1127                &window.next_frame.z_index_stack,
1128                PolychromeSprite {
1129                    order: 0,
1130                    bounds,
1131                    corner_radii: Default::default(),
1132                    content_mask,
1133                    tile,
1134                    grayscale: false,
1135                },
1136            );
1137        }
1138        Ok(())
1139    }
1140
1141    /// Paint a monochrome SVG into the scene for the next frame at the current stacking context.
1142    pub fn paint_svg(
1143        &mut self,
1144        bounds: Bounds<Pixels>,
1145        path: SharedString,
1146        color: Hsla,
1147    ) -> Result<()> {
1148        let scale_factor = self.scale_factor();
1149        let bounds = bounds.scale(scale_factor);
1150        // Render the SVG at twice the size to get a higher quality result.
1151        let params = RenderSvgParams {
1152            path,
1153            size: bounds
1154                .size
1155                .map(|pixels| DevicePixels::from((pixels.0 * 2.).ceil() as i32)),
1156        };
1157
1158        let tile =
1159            self.window
1160                .sprite_atlas
1161                .get_or_insert_with(&params.clone().into(), &mut || {
1162                    let bytes = self.svg_renderer.render(&params)?;
1163                    Ok((params.size, Cow::Owned(bytes)))
1164                })?;
1165        let content_mask = self.content_mask().scale(scale_factor);
1166
1167        let window = &mut *self.window;
1168        window.next_frame.scene_builder.insert(
1169            &window.next_frame.z_index_stack,
1170            MonochromeSprite {
1171                order: 0,
1172                bounds,
1173                content_mask,
1174                color,
1175                tile,
1176            },
1177        );
1178
1179        Ok(())
1180    }
1181
1182    /// Paint an image into the scene for the next frame at the current z-index.
1183    pub fn paint_image(
1184        &mut self,
1185        bounds: Bounds<Pixels>,
1186        corner_radii: Corners<Pixels>,
1187        data: Arc<ImageData>,
1188        grayscale: bool,
1189    ) -> Result<()> {
1190        let scale_factor = self.scale_factor();
1191        let bounds = bounds.scale(scale_factor);
1192        let params = RenderImageParams { image_id: data.id };
1193
1194        let tile = self
1195            .window
1196            .sprite_atlas
1197            .get_or_insert_with(&params.clone().into(), &mut || {
1198                Ok((data.size(), Cow::Borrowed(data.as_bytes())))
1199            })?;
1200        let content_mask = self.content_mask().scale(scale_factor);
1201        let corner_radii = corner_radii.scale(scale_factor);
1202
1203        let window = &mut *self.window;
1204        window.next_frame.scene_builder.insert(
1205            &window.next_frame.z_index_stack,
1206            PolychromeSprite {
1207                order: 0,
1208                bounds,
1209                content_mask,
1210                corner_radii,
1211                tile,
1212                grayscale,
1213            },
1214        );
1215        Ok(())
1216    }
1217
1218    /// Paint a surface into the scene for the next frame at the current z-index.
1219    pub fn paint_surface(&mut self, bounds: Bounds<Pixels>, image_buffer: CVImageBuffer) {
1220        let scale_factor = self.scale_factor();
1221        let bounds = bounds.scale(scale_factor);
1222        let content_mask = self.content_mask().scale(scale_factor);
1223        let window = &mut *self.window;
1224        window.next_frame.scene_builder.insert(
1225            &window.next_frame.z_index_stack,
1226            Surface {
1227                order: 0,
1228                bounds,
1229                content_mask,
1230                image_buffer,
1231            },
1232        );
1233    }
1234
1235    /// Draw pixels to the display for this window based on the contents of its scene.
1236    pub(crate) fn draw(&mut self) -> Scene {
1237        self.text_system().start_frame();
1238        self.window.platform_window.clear_input_handler();
1239        self.window.layout_engine.as_mut().unwrap().clear();
1240        self.window.next_frame.clear();
1241        let root_view = self.window.root_view.take().unwrap();
1242
1243        self.with_z_index(0, |cx| {
1244            cx.with_key_dispatch(Some(KeyContext::default()), None, |_, cx| {
1245                for (action_type, action_listeners) in &cx.app.global_action_listeners {
1246                    for action_listener in action_listeners.iter().cloned() {
1247                        cx.window.next_frame.dispatch_tree.on_action(
1248                            *action_type,
1249                            Rc::new(move |action, phase, cx| action_listener(action, phase, cx)),
1250                        )
1251                    }
1252                }
1253
1254                let available_space = cx.window.viewport_size.map(Into::into);
1255                root_view.draw(Point::default(), available_space, cx);
1256            })
1257        });
1258
1259        if let Some(active_drag) = self.app.active_drag.take() {
1260            self.with_z_index(ACTIVE_DRAG_Z_INDEX, |cx| {
1261                let offset = cx.mouse_position() - active_drag.cursor_offset;
1262                let available_space = size(AvailableSpace::MinContent, AvailableSpace::MinContent);
1263                active_drag.view.draw(offset, available_space, cx);
1264            });
1265            self.active_drag = Some(active_drag);
1266        } else if let Some(active_tooltip) = self.app.active_tooltip.take() {
1267            self.with_z_index(1, |cx| {
1268                let available_space = size(AvailableSpace::MinContent, AvailableSpace::MinContent);
1269                active_tooltip
1270                    .view
1271                    .draw(active_tooltip.cursor_offset, available_space, cx);
1272            });
1273        }
1274
1275        self.window
1276            .next_frame
1277            .dispatch_tree
1278            .preserve_pending_keystrokes(
1279                &mut self.window.rendered_frame.dispatch_tree,
1280                self.window.focus,
1281            );
1282        self.window.root_view = Some(root_view);
1283
1284        let window = &mut self.window;
1285        mem::swap(&mut window.rendered_frame, &mut window.next_frame);
1286
1287        let scene = self.window.rendered_frame.scene_builder.build();
1288
1289        // Set the cursor only if we're the active window.
1290        let cursor_style = self
1291            .window
1292            .requested_cursor_style
1293            .take()
1294            .unwrap_or(CursorStyle::Arrow);
1295        if self.is_window_active() {
1296            self.platform.set_cursor_style(cursor_style);
1297        }
1298
1299        self.window.dirty = false;
1300
1301        scene
1302    }
1303
1304    /// Dispatch a mouse or keyboard event on the window.
1305    pub fn dispatch_event(&mut self, event: InputEvent) -> bool {
1306        // Handlers may set this to false by calling `stop_propagation`
1307        self.app.propagate_event = true;
1308        self.window.default_prevented = false;
1309
1310        let event = match event {
1311            // Track the mouse position with our own state, since accessing the platform
1312            // API for the mouse position can only occur on the main thread.
1313            InputEvent::MouseMove(mouse_move) => {
1314                self.window.mouse_position = mouse_move.position;
1315                InputEvent::MouseMove(mouse_move)
1316            }
1317            InputEvent::MouseDown(mouse_down) => {
1318                self.window.mouse_position = mouse_down.position;
1319                InputEvent::MouseDown(mouse_down)
1320            }
1321            InputEvent::MouseUp(mouse_up) => {
1322                self.window.mouse_position = mouse_up.position;
1323                InputEvent::MouseUp(mouse_up)
1324            }
1325            // Translate dragging and dropping of external files from the operating system
1326            // to internal drag and drop events.
1327            InputEvent::FileDrop(file_drop) => match file_drop {
1328                FileDropEvent::Entered { position, files } => {
1329                    self.window.mouse_position = position;
1330                    if self.active_drag.is_none() {
1331                        self.active_drag = Some(AnyDrag {
1332                            view: self.build_view(|_| files).into(),
1333                            cursor_offset: position,
1334                        });
1335                    }
1336                    InputEvent::MouseMove(MouseMoveEvent {
1337                        position,
1338                        pressed_button: Some(MouseButton::Left),
1339                        modifiers: Modifiers::default(),
1340                    })
1341                }
1342                FileDropEvent::Pending { position } => {
1343                    self.window.mouse_position = position;
1344                    InputEvent::MouseMove(MouseMoveEvent {
1345                        position,
1346                        pressed_button: Some(MouseButton::Left),
1347                        modifiers: Modifiers::default(),
1348                    })
1349                }
1350                FileDropEvent::Submit { position } => {
1351                    self.activate(true);
1352                    self.window.mouse_position = position;
1353                    InputEvent::MouseUp(MouseUpEvent {
1354                        button: MouseButton::Left,
1355                        position,
1356                        modifiers: Modifiers::default(),
1357                        click_count: 1,
1358                    })
1359                }
1360                FileDropEvent::Exited => InputEvent::MouseUp(MouseUpEvent {
1361                    button: MouseButton::Left,
1362                    position: Point::default(),
1363                    modifiers: Modifiers::default(),
1364                    click_count: 1,
1365                }),
1366            },
1367            _ => event,
1368        };
1369
1370        if let Some(any_mouse_event) = event.mouse_event() {
1371            self.dispatch_mouse_event(any_mouse_event);
1372        } else if let Some(any_key_event) = event.keyboard_event() {
1373            self.dispatch_key_event(any_key_event);
1374        }
1375
1376        !self.app.propagate_event
1377    }
1378
1379    fn dispatch_mouse_event(&mut self, event: &dyn Any) {
1380        if let Some(mut handlers) = self
1381            .window
1382            .rendered_frame
1383            .mouse_listeners
1384            .remove(&event.type_id())
1385        {
1386            // Because handlers may add other handlers, we sort every time.
1387            handlers.sort_by(|(a, _), (b, _)| a.cmp(b));
1388
1389            // Capture phase, events bubble from back to front. Handlers for this phase are used for
1390            // special purposes, such as detecting events outside of a given Bounds.
1391            for (_, handler) in &mut handlers {
1392                handler(event, DispatchPhase::Capture, self);
1393                if !self.app.propagate_event {
1394                    break;
1395                }
1396            }
1397
1398            // Bubble phase, where most normal handlers do their work.
1399            if self.app.propagate_event {
1400                for (_, handler) in handlers.iter_mut().rev() {
1401                    handler(event, DispatchPhase::Bubble, self);
1402                    if !self.app.propagate_event {
1403                        break;
1404                    }
1405                }
1406            }
1407
1408            if self.app.propagate_event && event.downcast_ref::<MouseUpEvent>().is_some() {
1409                self.active_drag = None;
1410            }
1411
1412            self.window
1413                .rendered_frame
1414                .mouse_listeners
1415                .insert(event.type_id(), handlers);
1416        }
1417    }
1418
1419    fn dispatch_key_event(&mut self, event: &dyn Any) {
1420        let node_id = self
1421            .window
1422            .focus
1423            .and_then(|focus_id| {
1424                self.window
1425                    .rendered_frame
1426                    .dispatch_tree
1427                    .focusable_node_id(focus_id)
1428            })
1429            .unwrap_or_else(|| self.window.rendered_frame.dispatch_tree.root_node_id());
1430
1431        let dispatch_path = self
1432            .window
1433            .rendered_frame
1434            .dispatch_tree
1435            .dispatch_path(node_id);
1436
1437        let mut actions: Vec<Box<dyn Action>> = Vec::new();
1438
1439        // Capture phase
1440        let mut context_stack: SmallVec<[KeyContext; 16]> = SmallVec::new();
1441        self.propagate_event = true;
1442
1443        for node_id in &dispatch_path {
1444            let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1445
1446            if let Some(context) = node.context.clone() {
1447                context_stack.push(context);
1448            }
1449
1450            for key_listener in node.key_listeners.clone() {
1451                key_listener(event, DispatchPhase::Capture, self);
1452                if !self.propagate_event {
1453                    return;
1454                }
1455            }
1456        }
1457
1458        // Bubble phase
1459        for node_id in dispatch_path.iter().rev() {
1460            // Handle low level key events
1461            let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1462            for key_listener in node.key_listeners.clone() {
1463                key_listener(event, DispatchPhase::Bubble, self);
1464                if !self.propagate_event {
1465                    return;
1466                }
1467            }
1468
1469            // Match keystrokes
1470            let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1471            if node.context.is_some() {
1472                if let Some(key_down_event) = event.downcast_ref::<KeyDownEvent>() {
1473                    let mut new_actions = self
1474                        .window
1475                        .rendered_frame
1476                        .dispatch_tree
1477                        .dispatch_key(&key_down_event.keystroke, &context_stack);
1478                    actions.append(&mut new_actions);
1479                }
1480
1481                context_stack.pop();
1482            }
1483        }
1484
1485        for action in actions {
1486            self.dispatch_action_on_node(node_id, action.boxed_clone());
1487            if !self.propagate_event {
1488                self.dispatch_keystroke_observers(event, Some(action));
1489                return;
1490            }
1491        }
1492        self.dispatch_keystroke_observers(event, None);
1493    }
1494
1495    pub fn has_pending_keystrokes(&self) -> bool {
1496        self.window
1497            .rendered_frame
1498            .dispatch_tree
1499            .has_pending_keystrokes()
1500    }
1501
1502    fn dispatch_action_on_node(&mut self, node_id: DispatchNodeId, action: Box<dyn Action>) {
1503        let dispatch_path = self
1504            .window
1505            .rendered_frame
1506            .dispatch_tree
1507            .dispatch_path(node_id);
1508
1509        // Capture phase
1510        for node_id in &dispatch_path {
1511            let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1512            for DispatchActionListener {
1513                action_type,
1514                listener,
1515            } in node.action_listeners.clone()
1516            {
1517                let any_action = action.as_any();
1518                if action_type == any_action.type_id() {
1519                    listener(any_action, DispatchPhase::Capture, self);
1520                    if !self.propagate_event {
1521                        return;
1522                    }
1523                }
1524            }
1525        }
1526        // Bubble phase
1527        for node_id in dispatch_path.iter().rev() {
1528            let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1529            for DispatchActionListener {
1530                action_type,
1531                listener,
1532            } in node.action_listeners.clone()
1533            {
1534                let any_action = action.as_any();
1535                if action_type == any_action.type_id() {
1536                    self.propagate_event = false; // Actions stop propagation by default during the bubble phase
1537                    listener(any_action, DispatchPhase::Bubble, self);
1538                    if !self.propagate_event {
1539                        return;
1540                    }
1541                }
1542            }
1543        }
1544    }
1545
1546    /// Register the given handler to be invoked whenever the global of the given type
1547    /// is updated.
1548    pub fn observe_global<G: 'static>(
1549        &mut self,
1550        f: impl Fn(&mut WindowContext<'_>) + 'static,
1551    ) -> Subscription {
1552        let window_handle = self.window.handle;
1553        let (subscription, activate) = self.global_observers.insert(
1554            TypeId::of::<G>(),
1555            Box::new(move |cx| window_handle.update(cx, |_, cx| f(cx)).is_ok()),
1556        );
1557        self.app.defer(move |_| activate());
1558        subscription
1559    }
1560
1561    pub fn activate_window(&self) {
1562        self.window.platform_window.activate();
1563    }
1564
1565    pub fn minimize_window(&self) {
1566        self.window.platform_window.minimize();
1567    }
1568
1569    pub fn toggle_full_screen(&self) {
1570        self.window.platform_window.toggle_full_screen();
1571    }
1572
1573    pub fn prompt(
1574        &self,
1575        level: PromptLevel,
1576        msg: &str,
1577        answers: &[&str],
1578    ) -> oneshot::Receiver<usize> {
1579        self.window.platform_window.prompt(level, msg, answers)
1580    }
1581
1582    pub fn available_actions(&self) -> Vec<Box<dyn Action>> {
1583        let node_id = self
1584            .window
1585            .focus
1586            .and_then(|focus_id| {
1587                self.window
1588                    .rendered_frame
1589                    .dispatch_tree
1590                    .focusable_node_id(focus_id)
1591            })
1592            .unwrap_or_else(|| self.window.rendered_frame.dispatch_tree.root_node_id());
1593
1594        self.window
1595            .rendered_frame
1596            .dispatch_tree
1597            .available_actions(node_id)
1598    }
1599
1600    pub fn bindings_for_action(&self, action: &dyn Action) -> Vec<KeyBinding> {
1601        self.window
1602            .rendered_frame
1603            .dispatch_tree
1604            .bindings_for_action(
1605                action,
1606                &self.window.rendered_frame.dispatch_tree.context_stack,
1607            )
1608    }
1609
1610    pub fn bindings_for_action_in(
1611        &self,
1612        action: &dyn Action,
1613        focus_handle: &FocusHandle,
1614    ) -> Vec<KeyBinding> {
1615        let dispatch_tree = &self.window.rendered_frame.dispatch_tree;
1616
1617        let Some(node_id) = dispatch_tree.focusable_node_id(focus_handle.id) else {
1618            return vec![];
1619        };
1620        let context_stack = dispatch_tree
1621            .dispatch_path(node_id)
1622            .into_iter()
1623            .filter_map(|node_id| dispatch_tree.node(node_id).context.clone())
1624            .collect();
1625        dispatch_tree.bindings_for_action(action, &context_stack)
1626    }
1627
1628    pub fn listener_for<V: Render, E>(
1629        &self,
1630        view: &View<V>,
1631        f: impl Fn(&mut V, &E, &mut ViewContext<V>) + 'static,
1632    ) -> impl Fn(&E, &mut WindowContext) + 'static {
1633        let view = view.downgrade();
1634        move |e: &E, cx: &mut WindowContext| {
1635            view.update(cx, |view, cx| f(view, e, cx)).ok();
1636        }
1637    }
1638
1639    pub fn handler_for<V: Render>(
1640        &self,
1641        view: &View<V>,
1642        f: impl Fn(&mut V, &mut ViewContext<V>) + 'static,
1643    ) -> impl Fn(&mut WindowContext) {
1644        let view = view.downgrade();
1645        move |cx: &mut WindowContext| {
1646            view.update(cx, |view, cx| f(view, cx)).ok();
1647        }
1648    }
1649
1650    //========== ELEMENT RELATED FUNCTIONS ===========
1651    pub fn with_key_dispatch<R>(
1652        &mut self,
1653        context: Option<KeyContext>,
1654        focus_handle: Option<FocusHandle>,
1655        f: impl FnOnce(Option<FocusHandle>, &mut Self) -> R,
1656    ) -> R {
1657        let window = &mut self.window;
1658        window.next_frame.dispatch_tree.push_node(context.clone());
1659        if let Some(focus_handle) = focus_handle.as_ref() {
1660            window
1661                .next_frame
1662                .dispatch_tree
1663                .make_focusable(focus_handle.id);
1664        }
1665        let result = f(focus_handle, self);
1666
1667        self.window.next_frame.dispatch_tree.pop_node();
1668
1669        result
1670    }
1671
1672    /// Register a focus listener for the next frame only. It will be cleared
1673    /// on the next frame render. You should use this method only from within elements,
1674    /// and we may want to enforce that better via a different context type.
1675    // todo!() Move this to `FrameContext` to emphasize its individuality?
1676    pub fn on_focus_changed(
1677        &mut self,
1678        listener: impl Fn(&FocusEvent, &mut WindowContext) + 'static,
1679    ) {
1680        self.window
1681            .next_frame
1682            .focus_listeners
1683            .push(Box::new(move |event, cx| {
1684                listener(event, cx);
1685            }));
1686    }
1687
1688    /// Set an input handler, such as [ElementInputHandler], which interfaces with the
1689    /// platform to receive textual input with proper integration with concerns such
1690    /// as IME interactions.
1691    pub fn handle_input(
1692        &mut self,
1693        focus_handle: &FocusHandle,
1694        input_handler: impl PlatformInputHandler,
1695    ) {
1696        if focus_handle.is_focused(self) {
1697            self.window
1698                .platform_window
1699                .set_input_handler(Box::new(input_handler));
1700        }
1701    }
1702
1703    pub fn on_window_should_close(&mut self, f: impl Fn(&mut WindowContext) -> bool + 'static) {
1704        let mut this = self.to_async();
1705        self.window
1706            .platform_window
1707            .on_should_close(Box::new(move || this.update(|_, cx| f(cx)).unwrap_or(true)))
1708    }
1709}
1710
1711impl Context for WindowContext<'_> {
1712    type Result<T> = T;
1713
1714    fn build_model<T>(
1715        &mut self,
1716        build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
1717    ) -> Model<T>
1718    where
1719        T: 'static,
1720    {
1721        let slot = self.app.entities.reserve();
1722        let model = build_model(&mut ModelContext::new(&mut *self.app, slot.downgrade()));
1723        self.entities.insert(slot, model)
1724    }
1725
1726    fn update_model<T: 'static, R>(
1727        &mut self,
1728        model: &Model<T>,
1729        update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
1730    ) -> R {
1731        let mut entity = self.entities.lease(model);
1732        let result = update(
1733            &mut *entity,
1734            &mut ModelContext::new(&mut *self.app, model.downgrade()),
1735        );
1736        self.entities.end_lease(entity);
1737        result
1738    }
1739
1740    fn update_window<T, F>(&mut self, window: AnyWindowHandle, update: F) -> Result<T>
1741    where
1742        F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
1743    {
1744        if window == self.window.handle {
1745            let root_view = self.window.root_view.clone().unwrap();
1746            Ok(update(root_view, self))
1747        } else {
1748            window.update(self.app, update)
1749        }
1750    }
1751
1752    fn read_model<T, R>(
1753        &self,
1754        handle: &Model<T>,
1755        read: impl FnOnce(&T, &AppContext) -> R,
1756    ) -> Self::Result<R>
1757    where
1758        T: 'static,
1759    {
1760        let entity = self.entities.read(handle);
1761        read(&*entity, &*self.app)
1762    }
1763
1764    fn read_window<T, R>(
1765        &self,
1766        window: &WindowHandle<T>,
1767        read: impl FnOnce(View<T>, &AppContext) -> R,
1768    ) -> Result<R>
1769    where
1770        T: 'static,
1771    {
1772        if window.any_handle == self.window.handle {
1773            let root_view = self
1774                .window
1775                .root_view
1776                .clone()
1777                .unwrap()
1778                .downcast::<T>()
1779                .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
1780            Ok(read(root_view, self))
1781        } else {
1782            self.app.read_window(window, read)
1783        }
1784    }
1785}
1786
1787impl VisualContext for WindowContext<'_> {
1788    fn build_view<V>(
1789        &mut self,
1790        build_view_state: impl FnOnce(&mut ViewContext<'_, V>) -> V,
1791    ) -> Self::Result<View<V>>
1792    where
1793        V: 'static + Render,
1794    {
1795        let slot = self.app.entities.reserve();
1796        let view = View {
1797            model: slot.clone(),
1798        };
1799        let mut cx = ViewContext::new(&mut *self.app, &mut *self.window, &view);
1800        let entity = build_view_state(&mut cx);
1801        cx.entities.insert(slot, entity);
1802
1803        cx.new_view_observers
1804            .clone()
1805            .retain(&TypeId::of::<V>(), |observer| {
1806                let any_view = AnyView::from(view.clone());
1807                (observer)(any_view, self);
1808                true
1809            });
1810
1811        view
1812    }
1813
1814    /// Update the given view. Prefer calling `View::update` instead, which calls this method.
1815    fn update_view<T: 'static, R>(
1816        &mut self,
1817        view: &View<T>,
1818        update: impl FnOnce(&mut T, &mut ViewContext<'_, T>) -> R,
1819    ) -> Self::Result<R> {
1820        let mut lease = self.app.entities.lease(&view.model);
1821        let mut cx = ViewContext::new(&mut *self.app, &mut *self.window, &view);
1822        let result = update(&mut *lease, &mut cx);
1823        cx.app.entities.end_lease(lease);
1824        result
1825    }
1826
1827    fn replace_root_view<V>(
1828        &mut self,
1829        build_view: impl FnOnce(&mut ViewContext<'_, V>) -> V,
1830    ) -> Self::Result<View<V>>
1831    where
1832        V: 'static + Render,
1833    {
1834        let slot = self.app.entities.reserve();
1835        let view = View {
1836            model: slot.clone(),
1837        };
1838        let mut cx = ViewContext::new(&mut *self.app, &mut *self.window, &view);
1839        let entity = build_view(&mut cx);
1840        self.entities.insert(slot, entity);
1841        self.window.root_view = Some(view.clone().into());
1842        view
1843    }
1844
1845    fn focus_view<V: crate::FocusableView>(&mut self, view: &View<V>) -> Self::Result<()> {
1846        self.update_view(view, |view, cx| {
1847            view.focus_handle(cx).clone().focus(cx);
1848        })
1849    }
1850
1851    fn dismiss_view<V>(&mut self, view: &View<V>) -> Self::Result<()>
1852    where
1853        V: ManagedView,
1854    {
1855        self.update_view(view, |_, cx| cx.emit(DismissEvent))
1856    }
1857}
1858
1859impl<'a> std::ops::Deref for WindowContext<'a> {
1860    type Target = AppContext;
1861
1862    fn deref(&self) -> &Self::Target {
1863        &self.app
1864    }
1865}
1866
1867impl<'a> std::ops::DerefMut for WindowContext<'a> {
1868    fn deref_mut(&mut self) -> &mut Self::Target {
1869        &mut self.app
1870    }
1871}
1872
1873impl<'a> Borrow<AppContext> for WindowContext<'a> {
1874    fn borrow(&self) -> &AppContext {
1875        &self.app
1876    }
1877}
1878
1879impl<'a> BorrowMut<AppContext> for WindowContext<'a> {
1880    fn borrow_mut(&mut self) -> &mut AppContext {
1881        &mut self.app
1882    }
1883}
1884
1885pub trait BorrowWindow: BorrowMut<Window> + BorrowMut<AppContext> {
1886    fn app_mut(&mut self) -> &mut AppContext {
1887        self.borrow_mut()
1888    }
1889
1890    fn app(&self) -> &AppContext {
1891        self.borrow()
1892    }
1893
1894    fn window(&self) -> &Window {
1895        self.borrow()
1896    }
1897
1898    fn window_mut(&mut self) -> &mut Window {
1899        self.borrow_mut()
1900    }
1901
1902    /// Pushes the given element id onto the global stack and invokes the given closure
1903    /// with a `GlobalElementId`, which disambiguates the given id in the context of its ancestor
1904    /// ids. Because elements are discarded and recreated on each frame, the `GlobalElementId` is
1905    /// used to associate state with identified elements across separate frames.
1906    fn with_element_id<R>(
1907        &mut self,
1908        id: Option<impl Into<ElementId>>,
1909        f: impl FnOnce(&mut Self) -> R,
1910    ) -> R {
1911        if let Some(id) = id.map(Into::into) {
1912            let window = self.window_mut();
1913            window.element_id_stack.push(id.into());
1914            let result = f(self);
1915            let window: &mut Window = self.borrow_mut();
1916            window.element_id_stack.pop();
1917            result
1918        } else {
1919            f(self)
1920        }
1921    }
1922
1923    /// Invoke the given function with the given content mask after intersecting it
1924    /// with the current mask.
1925    fn with_content_mask<R>(
1926        &mut self,
1927        mask: Option<ContentMask<Pixels>>,
1928        f: impl FnOnce(&mut Self) -> R,
1929    ) -> R {
1930        if let Some(mask) = mask {
1931            let mask = mask.intersect(&self.content_mask());
1932            self.window_mut().next_frame.content_mask_stack.push(mask);
1933            let result = f(self);
1934            self.window_mut().next_frame.content_mask_stack.pop();
1935            result
1936        } else {
1937            f(self)
1938        }
1939    }
1940
1941    /// Invoke the given function with the content mask reset to that
1942    /// of the window.
1943    fn break_content_mask<R>(&mut self, f: impl FnOnce(&mut Self) -> R) -> R {
1944        let mask = ContentMask {
1945            bounds: Bounds {
1946                origin: Point::default(),
1947                size: self.window().viewport_size,
1948            },
1949        };
1950        self.window_mut().next_frame.content_mask_stack.push(mask);
1951        let result = f(self);
1952        self.window_mut().next_frame.content_mask_stack.pop();
1953        result
1954    }
1955
1956    /// Update the global element offset relative to the current offset. This is used to implement
1957    /// scrolling.
1958    fn with_element_offset<R>(
1959        &mut self,
1960        offset: Point<Pixels>,
1961        f: impl FnOnce(&mut Self) -> R,
1962    ) -> R {
1963        if offset.is_zero() {
1964            return f(self);
1965        };
1966
1967        let abs_offset = self.element_offset() + offset;
1968        self.with_absolute_element_offset(abs_offset, f)
1969    }
1970
1971    /// Update the global element offset based on the given offset. This is used to implement
1972    /// drag handles and other manual painting of elements.
1973    fn with_absolute_element_offset<R>(
1974        &mut self,
1975        offset: Point<Pixels>,
1976        f: impl FnOnce(&mut Self) -> R,
1977    ) -> R {
1978        self.window_mut()
1979            .next_frame
1980            .element_offset_stack
1981            .push(offset);
1982        let result = f(self);
1983        self.window_mut().next_frame.element_offset_stack.pop();
1984        result
1985    }
1986
1987    /// Obtain the current element offset.
1988    fn element_offset(&self) -> Point<Pixels> {
1989        self.window()
1990            .next_frame
1991            .element_offset_stack
1992            .last()
1993            .copied()
1994            .unwrap_or_default()
1995    }
1996
1997    /// Update or initialize state for an element with the given id that lives across multiple
1998    /// frames. If an element with this id existed in the rendered frame, its state will be passed
1999    /// to the given closure. The state returned by the closure will be stored so it can be referenced
2000    /// when drawing the next frame.
2001    fn with_element_state<S, R>(
2002        &mut self,
2003        id: ElementId,
2004        f: impl FnOnce(Option<S>, &mut Self) -> (R, S),
2005    ) -> R
2006    where
2007        S: 'static,
2008    {
2009        self.with_element_id(Some(id), |cx| {
2010            let global_id = cx.window().element_id_stack.clone();
2011
2012            if let Some(any) = cx
2013                .window_mut()
2014                .next_frame
2015                .element_states
2016                .remove(&global_id)
2017                .or_else(|| {
2018                    cx.window_mut()
2019                        .rendered_frame
2020                        .element_states
2021                        .remove(&global_id)
2022                })
2023            {
2024                let ElementStateBox {
2025                    inner,
2026
2027                    #[cfg(debug_assertions)]
2028                    type_name
2029                } = any;
2030                // Using the extra inner option to avoid needing to reallocate a new box.
2031                let mut state_box = inner
2032                    .downcast::<Option<S>>()
2033                    .map_err(|_| {
2034                        #[cfg(debug_assertions)]
2035                        {
2036                            anyhow!(
2037                                "invalid element state type for id, requested_type {:?}, actual type: {:?}",
2038                                std::any::type_name::<S>(),
2039                                type_name
2040                            )
2041                        }
2042
2043                        #[cfg(not(debug_assertions))]
2044                        {
2045                            anyhow!(
2046                                "invalid element state type for id, requested_type {:?}",
2047                                std::any::type_name::<S>(),
2048                            )
2049                        }
2050                    })
2051                    .unwrap();
2052
2053                // Actual: Option<AnyElement> <- View
2054                // Requested: () <- AnyElemet
2055                let state = state_box
2056                    .take()
2057                    .expect("element state is already on the stack");
2058                let (result, state) = f(Some(state), cx);
2059                state_box.replace(state);
2060                cx.window_mut()
2061                    .next_frame
2062                    .element_states
2063                    .insert(global_id, ElementStateBox {
2064                        inner: state_box,
2065
2066                        #[cfg(debug_assertions)]
2067                        type_name
2068                    });
2069                result
2070            } else {
2071                let (result, state) = f(None, cx);
2072                cx.window_mut()
2073                    .next_frame
2074                    .element_states
2075                    .insert(global_id,
2076                        ElementStateBox {
2077                            inner: Box::new(Some(state)),
2078
2079                            #[cfg(debug_assertions)]
2080                            type_name: std::any::type_name::<S>()
2081                        }
2082
2083                    );
2084                result
2085            }
2086        })
2087    }
2088
2089    /// Obtain the current content mask.
2090    fn content_mask(&self) -> ContentMask<Pixels> {
2091        self.window()
2092            .next_frame
2093            .content_mask_stack
2094            .last()
2095            .cloned()
2096            .unwrap_or_else(|| ContentMask {
2097                bounds: Bounds {
2098                    origin: Point::default(),
2099                    size: self.window().viewport_size,
2100                },
2101            })
2102    }
2103
2104    /// The size of an em for the base font of the application. Adjusting this value allows the
2105    /// UI to scale, just like zooming a web page.
2106    fn rem_size(&self) -> Pixels {
2107        self.window().rem_size
2108    }
2109}
2110
2111impl Borrow<Window> for WindowContext<'_> {
2112    fn borrow(&self) -> &Window {
2113        &self.window
2114    }
2115}
2116
2117impl BorrowMut<Window> for WindowContext<'_> {
2118    fn borrow_mut(&mut self) -> &mut Window {
2119        &mut self.window
2120    }
2121}
2122
2123impl<T> BorrowWindow for T where T: BorrowMut<AppContext> + BorrowMut<Window> {}
2124
2125pub struct ViewContext<'a, V> {
2126    window_cx: WindowContext<'a>,
2127    view: &'a View<V>,
2128}
2129
2130impl<V> Borrow<AppContext> for ViewContext<'_, V> {
2131    fn borrow(&self) -> &AppContext {
2132        &*self.window_cx.app
2133    }
2134}
2135
2136impl<V> BorrowMut<AppContext> for ViewContext<'_, V> {
2137    fn borrow_mut(&mut self) -> &mut AppContext {
2138        &mut *self.window_cx.app
2139    }
2140}
2141
2142impl<V> Borrow<Window> for ViewContext<'_, V> {
2143    fn borrow(&self) -> &Window {
2144        &*self.window_cx.window
2145    }
2146}
2147
2148impl<V> BorrowMut<Window> for ViewContext<'_, V> {
2149    fn borrow_mut(&mut self) -> &mut Window {
2150        &mut *self.window_cx.window
2151    }
2152}
2153
2154impl<'a, V: 'static> ViewContext<'a, V> {
2155    pub(crate) fn new(app: &'a mut AppContext, window: &'a mut Window, view: &'a View<V>) -> Self {
2156        Self {
2157            window_cx: WindowContext::new(app, window),
2158            view,
2159        }
2160    }
2161
2162    pub fn entity_id(&self) -> EntityId {
2163        self.view.entity_id()
2164    }
2165
2166    pub fn view(&self) -> &View<V> {
2167        self.view
2168    }
2169
2170    pub fn model(&self) -> &Model<V> {
2171        &self.view.model
2172    }
2173
2174    /// Access the underlying window context.
2175    pub fn window_context(&mut self) -> &mut WindowContext<'a> {
2176        &mut self.window_cx
2177    }
2178
2179    pub fn with_z_index<R>(&mut self, z_index: u32, f: impl FnOnce(&mut Self) -> R) -> R {
2180        self.window.next_frame.z_index_stack.push(z_index);
2181        let result = f(self);
2182        self.window.next_frame.z_index_stack.pop();
2183        result
2184    }
2185
2186    pub fn on_next_frame(&mut self, f: impl FnOnce(&mut V, &mut ViewContext<V>) + 'static)
2187    where
2188        V: 'static,
2189    {
2190        let view = self.view().clone();
2191        self.window_cx.on_next_frame(move |cx| view.update(cx, f));
2192    }
2193
2194    /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
2195    /// that are currently on the stack to be returned to the app.
2196    pub fn defer(&mut self, f: impl FnOnce(&mut V, &mut ViewContext<V>) + 'static) {
2197        let view = self.view().downgrade();
2198        self.window_cx.defer(move |cx| {
2199            view.update(cx, f).ok();
2200        });
2201    }
2202
2203    pub fn observe<V2, E>(
2204        &mut self,
2205        entity: &E,
2206        mut on_notify: impl FnMut(&mut V, E, &mut ViewContext<'_, V>) + 'static,
2207    ) -> Subscription
2208    where
2209        V2: 'static,
2210        V: 'static,
2211        E: Entity<V2>,
2212    {
2213        let view = self.view().downgrade();
2214        let entity_id = entity.entity_id();
2215        let entity = entity.downgrade();
2216        let window_handle = self.window.handle;
2217        let (subscription, activate) = self.app.observers.insert(
2218            entity_id,
2219            Box::new(move |cx| {
2220                window_handle
2221                    .update(cx, |_, cx| {
2222                        if let Some(handle) = E::upgrade_from(&entity) {
2223                            view.update(cx, |this, cx| on_notify(this, handle, cx))
2224                                .is_ok()
2225                        } else {
2226                            false
2227                        }
2228                    })
2229                    .unwrap_or(false)
2230            }),
2231        );
2232        self.app.defer(move |_| activate());
2233        subscription
2234    }
2235
2236    pub fn subscribe<V2, E, Evt>(
2237        &mut self,
2238        entity: &E,
2239        mut on_event: impl FnMut(&mut V, E, &Evt, &mut ViewContext<'_, V>) + 'static,
2240    ) -> Subscription
2241    where
2242        V2: EventEmitter<Evt>,
2243        E: Entity<V2>,
2244        Evt: 'static,
2245    {
2246        let view = self.view().downgrade();
2247        let entity_id = entity.entity_id();
2248        let handle = entity.downgrade();
2249        let window_handle = self.window.handle;
2250        let (subscription, activate) = self.app.event_listeners.insert(
2251            entity_id,
2252            (
2253                TypeId::of::<Evt>(),
2254                Box::new(move |event, cx| {
2255                    window_handle
2256                        .update(cx, |_, cx| {
2257                            if let Some(handle) = E::upgrade_from(&handle) {
2258                                let event = event.downcast_ref().expect("invalid event type");
2259                                view.update(cx, |this, cx| on_event(this, handle, event, cx))
2260                                    .is_ok()
2261                            } else {
2262                                false
2263                            }
2264                        })
2265                        .unwrap_or(false)
2266                }),
2267            ),
2268        );
2269        self.app.defer(move |_| activate());
2270        subscription
2271    }
2272
2273    pub fn on_release(
2274        &mut self,
2275        on_release: impl FnOnce(&mut V, &mut WindowContext) + 'static,
2276    ) -> Subscription {
2277        let window_handle = self.window.handle;
2278        let (subscription, activate) = self.app.release_listeners.insert(
2279            self.view.model.entity_id,
2280            Box::new(move |this, cx| {
2281                let this = this.downcast_mut().expect("invalid entity type");
2282                let _ = window_handle.update(cx, |_, cx| on_release(this, cx));
2283            }),
2284        );
2285        activate();
2286        subscription
2287    }
2288
2289    pub fn observe_release<V2, E>(
2290        &mut self,
2291        entity: &E,
2292        mut on_release: impl FnMut(&mut V, &mut V2, &mut ViewContext<'_, V>) + 'static,
2293    ) -> Subscription
2294    where
2295        V: 'static,
2296        V2: 'static,
2297        E: Entity<V2>,
2298    {
2299        let view = self.view().downgrade();
2300        let entity_id = entity.entity_id();
2301        let window_handle = self.window.handle;
2302        let (subscription, activate) = self.app.release_listeners.insert(
2303            entity_id,
2304            Box::new(move |entity, cx| {
2305                let entity = entity.downcast_mut().expect("invalid entity type");
2306                let _ = window_handle.update(cx, |_, cx| {
2307                    view.update(cx, |this, cx| on_release(this, entity, cx))
2308                });
2309            }),
2310        );
2311        activate();
2312        subscription
2313    }
2314
2315    pub fn notify(&mut self) {
2316        self.window_cx.notify();
2317        self.window_cx.app.push_effect(Effect::Notify {
2318            emitter: self.view.model.entity_id,
2319        });
2320    }
2321
2322    pub fn observe_window_bounds(
2323        &mut self,
2324        mut callback: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2325    ) -> Subscription {
2326        let view = self.view.downgrade();
2327        let (subscription, activate) = self.window.bounds_observers.insert(
2328            (),
2329            Box::new(move |cx| view.update(cx, |view, cx| callback(view, cx)).is_ok()),
2330        );
2331        activate();
2332        subscription
2333    }
2334
2335    pub fn observe_window_activation(
2336        &mut self,
2337        mut callback: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2338    ) -> Subscription {
2339        let view = self.view.downgrade();
2340        let (subscription, activate) = self.window.activation_observers.insert(
2341            (),
2342            Box::new(move |cx| view.update(cx, |view, cx| callback(view, cx)).is_ok()),
2343        );
2344        activate();
2345        subscription
2346    }
2347
2348    /// Register a listener to be called when the given focus handle receives focus.
2349    /// Unlike [on_focus_changed], returns a subscription and persists until the subscription
2350    /// is dropped.
2351    pub fn on_focus(
2352        &mut self,
2353        handle: &FocusHandle,
2354        mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2355    ) -> Subscription {
2356        let view = self.view.downgrade();
2357        let focus_id = handle.id;
2358        let (subscription, activate) = self.window.focus_listeners.insert(
2359            (),
2360            Box::new(move |event, cx| {
2361                view.update(cx, |view, cx| {
2362                    if event.focused.as_ref().map(|focused| focused.id) == Some(focus_id) {
2363                        listener(view, cx)
2364                    }
2365                })
2366                .is_ok()
2367            }),
2368        );
2369        self.app.defer(move |_| activate());
2370        subscription
2371    }
2372
2373    /// Register a listener to be called when the given focus handle or one of its descendants receives focus.
2374    /// Unlike [on_focus_changed], returns a subscription and persists until the subscription
2375    /// is dropped.
2376    pub fn on_focus_in(
2377        &mut self,
2378        handle: &FocusHandle,
2379        mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2380    ) -> Subscription {
2381        let view = self.view.downgrade();
2382        let focus_id = handle.id;
2383        let (subscription, activate) = self.window.focus_listeners.insert(
2384            (),
2385            Box::new(move |event, cx| {
2386                view.update(cx, |view, cx| {
2387                    if event
2388                        .focused
2389                        .as_ref()
2390                        .map_or(false, |focused| focus_id.contains(focused.id, cx))
2391                    {
2392                        listener(view, cx)
2393                    }
2394                })
2395                .is_ok()
2396            }),
2397        );
2398        self.app.defer(move |_| activate());
2399        subscription
2400    }
2401
2402    /// Register a listener to be called when the given focus handle loses focus.
2403    /// Unlike [on_focus_changed], returns a subscription and persists until the subscription
2404    /// is dropped.
2405    pub fn on_blur(
2406        &mut self,
2407        handle: &FocusHandle,
2408        mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2409    ) -> Subscription {
2410        let view = self.view.downgrade();
2411        let focus_id = handle.id;
2412        let (subscription, activate) = self.window.focus_listeners.insert(
2413            (),
2414            Box::new(move |event, cx| {
2415                view.update(cx, |view, cx| {
2416                    if event.blurred.as_ref().map(|blurred| blurred.id) == Some(focus_id) {
2417                        listener(view, cx)
2418                    }
2419                })
2420                .is_ok()
2421            }),
2422        );
2423        self.app.defer(move |_| activate());
2424        subscription
2425    }
2426
2427    /// Register a listener to be called when the given focus handle or one of its descendants loses focus.
2428    /// Unlike [on_focus_changed], returns a subscription and persists until the subscription
2429    /// is dropped.
2430    pub fn on_focus_out(
2431        &mut self,
2432        handle: &FocusHandle,
2433        mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2434    ) -> Subscription {
2435        let view = self.view.downgrade();
2436        let focus_id = handle.id;
2437        let (subscription, activate) = self.window.focus_listeners.insert(
2438            (),
2439            Box::new(move |event, cx| {
2440                view.update(cx, |view, cx| {
2441                    if event
2442                        .blurred
2443                        .as_ref()
2444                        .map_or(false, |blurred| focus_id.contains(blurred.id, cx))
2445                    {
2446                        listener(view, cx)
2447                    }
2448                })
2449                .is_ok()
2450            }),
2451        );
2452        self.app.defer(move |_| activate());
2453        subscription
2454    }
2455
2456    pub fn spawn<Fut, R>(
2457        &mut self,
2458        f: impl FnOnce(WeakView<V>, AsyncWindowContext) -> Fut,
2459    ) -> Task<R>
2460    where
2461        R: 'static,
2462        Fut: Future<Output = R> + 'static,
2463    {
2464        let view = self.view().downgrade();
2465        self.window_cx.spawn(|cx| f(view, cx))
2466    }
2467
2468    pub fn update_global<G, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R
2469    where
2470        G: 'static,
2471    {
2472        let mut global = self.app.lease_global::<G>();
2473        let result = f(&mut global, self);
2474        self.app.end_global_lease(global);
2475        result
2476    }
2477
2478    pub fn observe_global<G: 'static>(
2479        &mut self,
2480        mut f: impl FnMut(&mut V, &mut ViewContext<'_, V>) + 'static,
2481    ) -> Subscription {
2482        let window_handle = self.window.handle;
2483        let view = self.view().downgrade();
2484        let (subscription, activate) = self.global_observers.insert(
2485            TypeId::of::<G>(),
2486            Box::new(move |cx| {
2487                window_handle
2488                    .update(cx, |_, cx| view.update(cx, |view, cx| f(view, cx)).is_ok())
2489                    .unwrap_or(false)
2490            }),
2491        );
2492        self.app.defer(move |_| activate());
2493        subscription
2494    }
2495
2496    pub fn on_mouse_event<Event: 'static>(
2497        &mut self,
2498        handler: impl Fn(&mut V, &Event, DispatchPhase, &mut ViewContext<V>) + 'static,
2499    ) {
2500        let handle = self.view().clone();
2501        self.window_cx.on_mouse_event(move |event, phase, cx| {
2502            handle.update(cx, |view, cx| {
2503                handler(view, event, phase, cx);
2504            })
2505        });
2506    }
2507
2508    pub fn on_key_event<Event: 'static>(
2509        &mut self,
2510        handler: impl Fn(&mut V, &Event, DispatchPhase, &mut ViewContext<V>) + 'static,
2511    ) {
2512        let handle = self.view().clone();
2513        self.window_cx.on_key_event(move |event, phase, cx| {
2514            handle.update(cx, |view, cx| {
2515                handler(view, event, phase, cx);
2516            })
2517        });
2518    }
2519
2520    pub fn on_action(
2521        &mut self,
2522        action_type: TypeId,
2523        handler: impl Fn(&mut V, &dyn Any, DispatchPhase, &mut ViewContext<V>) + 'static,
2524    ) {
2525        let handle = self.view().clone();
2526        self.window_cx
2527            .on_action(action_type, move |action, phase, cx| {
2528                handle.update(cx, |view, cx| {
2529                    handler(view, action, phase, cx);
2530                })
2531            });
2532    }
2533
2534    pub fn emit<Evt>(&mut self, event: Evt)
2535    where
2536        Evt: 'static,
2537        V: EventEmitter<Evt>,
2538    {
2539        let emitter = self.view.model.entity_id;
2540        self.app.push_effect(Effect::Emit {
2541            emitter,
2542            event_type: TypeId::of::<Evt>(),
2543            event: Box::new(event),
2544        });
2545    }
2546
2547    pub fn focus_self(&mut self)
2548    where
2549        V: FocusableView,
2550    {
2551        self.defer(|view, cx| view.focus_handle(cx).focus(cx))
2552    }
2553
2554    pub fn dismiss_self(&mut self)
2555    where
2556        V: ManagedView,
2557    {
2558        self.defer(|_, cx| cx.emit(DismissEvent))
2559    }
2560
2561    pub fn listener<E>(
2562        &self,
2563        f: impl Fn(&mut V, &E, &mut ViewContext<V>) + 'static,
2564    ) -> impl Fn(&E, &mut WindowContext) + 'static {
2565        let view = self.view().downgrade();
2566        move |e: &E, cx: &mut WindowContext| {
2567            view.update(cx, |view, cx| f(view, e, cx)).ok();
2568        }
2569    }
2570}
2571
2572impl<V> Context for ViewContext<'_, V> {
2573    type Result<U> = U;
2574
2575    fn build_model<T: 'static>(
2576        &mut self,
2577        build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
2578    ) -> Model<T> {
2579        self.window_cx.build_model(build_model)
2580    }
2581
2582    fn update_model<T: 'static, R>(
2583        &mut self,
2584        model: &Model<T>,
2585        update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
2586    ) -> R {
2587        self.window_cx.update_model(model, update)
2588    }
2589
2590    fn update_window<T, F>(&mut self, window: AnyWindowHandle, update: F) -> Result<T>
2591    where
2592        F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
2593    {
2594        self.window_cx.update_window(window, update)
2595    }
2596
2597    fn read_model<T, R>(
2598        &self,
2599        handle: &Model<T>,
2600        read: impl FnOnce(&T, &AppContext) -> R,
2601    ) -> Self::Result<R>
2602    where
2603        T: 'static,
2604    {
2605        self.window_cx.read_model(handle, read)
2606    }
2607
2608    fn read_window<T, R>(
2609        &self,
2610        window: &WindowHandle<T>,
2611        read: impl FnOnce(View<T>, &AppContext) -> R,
2612    ) -> Result<R>
2613    where
2614        T: 'static,
2615    {
2616        self.window_cx.read_window(window, read)
2617    }
2618}
2619
2620impl<V: 'static> VisualContext for ViewContext<'_, V> {
2621    fn build_view<W: Render + 'static>(
2622        &mut self,
2623        build_view_state: impl FnOnce(&mut ViewContext<'_, W>) -> W,
2624    ) -> Self::Result<View<W>> {
2625        self.window_cx.build_view(build_view_state)
2626    }
2627
2628    fn update_view<V2: 'static, R>(
2629        &mut self,
2630        view: &View<V2>,
2631        update: impl FnOnce(&mut V2, &mut ViewContext<'_, V2>) -> R,
2632    ) -> Self::Result<R> {
2633        self.window_cx.update_view(view, update)
2634    }
2635
2636    fn replace_root_view<W>(
2637        &mut self,
2638        build_view: impl FnOnce(&mut ViewContext<'_, W>) -> W,
2639    ) -> Self::Result<View<W>>
2640    where
2641        W: 'static + Render,
2642    {
2643        self.window_cx.replace_root_view(build_view)
2644    }
2645
2646    fn focus_view<W: FocusableView>(&mut self, view: &View<W>) -> Self::Result<()> {
2647        self.window_cx.focus_view(view)
2648    }
2649
2650    fn dismiss_view<W: ManagedView>(&mut self, view: &View<W>) -> Self::Result<()> {
2651        self.window_cx.dismiss_view(view)
2652    }
2653}
2654
2655impl<'a, V> std::ops::Deref for ViewContext<'a, V> {
2656    type Target = WindowContext<'a>;
2657
2658    fn deref(&self) -> &Self::Target {
2659        &self.window_cx
2660    }
2661}
2662
2663impl<'a, V> std::ops::DerefMut for ViewContext<'a, V> {
2664    fn deref_mut(&mut self) -> &mut Self::Target {
2665        &mut self.window_cx
2666    }
2667}
2668
2669// #[derive(Clone, Copy, Eq, PartialEq, Hash)]
2670slotmap::new_key_type! { pub struct WindowId; }
2671
2672impl WindowId {
2673    pub fn as_u64(&self) -> u64 {
2674        self.0.as_ffi()
2675    }
2676}
2677
2678#[derive(Deref, DerefMut)]
2679pub struct WindowHandle<V> {
2680    #[deref]
2681    #[deref_mut]
2682    pub(crate) any_handle: AnyWindowHandle,
2683    state_type: PhantomData<V>,
2684}
2685
2686impl<V: 'static + Render> WindowHandle<V> {
2687    pub fn new(id: WindowId) -> Self {
2688        WindowHandle {
2689            any_handle: AnyWindowHandle {
2690                id,
2691                state_type: TypeId::of::<V>(),
2692            },
2693            state_type: PhantomData,
2694        }
2695    }
2696
2697    pub fn root<C>(&self, cx: &mut C) -> Result<View<V>>
2698    where
2699        C: Context,
2700    {
2701        Flatten::flatten(cx.update_window(self.any_handle, |root_view, _| {
2702            root_view
2703                .downcast::<V>()
2704                .map_err(|_| anyhow!("the type of the window's root view has changed"))
2705        }))
2706    }
2707
2708    pub fn update<C, R>(
2709        &self,
2710        cx: &mut C,
2711        update: impl FnOnce(&mut V, &mut ViewContext<'_, V>) -> R,
2712    ) -> Result<R>
2713    where
2714        C: Context,
2715    {
2716        cx.update_window(self.any_handle, |root_view, cx| {
2717            let view = root_view
2718                .downcast::<V>()
2719                .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
2720            Ok(cx.update_view(&view, update))
2721        })?
2722    }
2723
2724    pub fn read<'a>(&self, cx: &'a AppContext) -> Result<&'a V> {
2725        let x = cx
2726            .windows
2727            .get(self.id)
2728            .and_then(|window| {
2729                window
2730                    .as_ref()
2731                    .and_then(|window| window.root_view.clone())
2732                    .map(|root_view| root_view.downcast::<V>())
2733            })
2734            .ok_or_else(|| anyhow!("window not found"))?
2735            .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
2736
2737        Ok(x.read(cx))
2738    }
2739
2740    pub fn read_with<C, R>(&self, cx: &C, read_with: impl FnOnce(&V, &AppContext) -> R) -> Result<R>
2741    where
2742        C: Context,
2743    {
2744        cx.read_window(self, |root_view, cx| read_with(root_view.read(cx), cx))
2745    }
2746
2747    pub fn root_view<C>(&self, cx: &C) -> Result<View<V>>
2748    where
2749        C: Context,
2750    {
2751        cx.read_window(self, |root_view, _cx| root_view.clone())
2752    }
2753
2754    pub fn is_active(&self, cx: &AppContext) -> Option<bool> {
2755        cx.windows
2756            .get(self.id)
2757            .and_then(|window| window.as_ref().map(|window| window.active))
2758    }
2759}
2760
2761impl<V> Copy for WindowHandle<V> {}
2762
2763impl<V> Clone for WindowHandle<V> {
2764    fn clone(&self) -> Self {
2765        WindowHandle {
2766            any_handle: self.any_handle,
2767            state_type: PhantomData,
2768        }
2769    }
2770}
2771
2772impl<V> PartialEq for WindowHandle<V> {
2773    fn eq(&self, other: &Self) -> bool {
2774        self.any_handle == other.any_handle
2775    }
2776}
2777
2778impl<V> Eq for WindowHandle<V> {}
2779
2780impl<V> Hash for WindowHandle<V> {
2781    fn hash<H: Hasher>(&self, state: &mut H) {
2782        self.any_handle.hash(state);
2783    }
2784}
2785
2786impl<V: 'static> Into<AnyWindowHandle> for WindowHandle<V> {
2787    fn into(self) -> AnyWindowHandle {
2788        self.any_handle
2789    }
2790}
2791
2792#[derive(Copy, Clone, PartialEq, Eq, Hash)]
2793pub struct AnyWindowHandle {
2794    pub(crate) id: WindowId,
2795    state_type: TypeId,
2796}
2797
2798impl AnyWindowHandle {
2799    pub fn window_id(&self) -> WindowId {
2800        self.id
2801    }
2802
2803    pub fn downcast<T: 'static>(&self) -> Option<WindowHandle<T>> {
2804        if TypeId::of::<T>() == self.state_type {
2805            Some(WindowHandle {
2806                any_handle: *self,
2807                state_type: PhantomData,
2808            })
2809        } else {
2810            None
2811        }
2812    }
2813
2814    pub fn update<C, R>(
2815        self,
2816        cx: &mut C,
2817        update: impl FnOnce(AnyView, &mut WindowContext<'_>) -> R,
2818    ) -> Result<R>
2819    where
2820        C: Context,
2821    {
2822        cx.update_window(self, update)
2823    }
2824
2825    pub fn read<T, C, R>(self, cx: &C, read: impl FnOnce(View<T>, &AppContext) -> R) -> Result<R>
2826    where
2827        C: Context,
2828        T: 'static,
2829    {
2830        let view = self
2831            .downcast::<T>()
2832            .context("the type of the window's root view has changed")?;
2833
2834        cx.read_window(&view, read)
2835    }
2836}
2837
2838#[cfg(any(test, feature = "test-support"))]
2839impl From<SmallVec<[u32; 16]>> for StackingOrder {
2840    fn from(small_vec: SmallVec<[u32; 16]>) -> Self {
2841        StackingOrder(small_vec)
2842    }
2843}
2844
2845#[derive(Clone, Debug, Eq, PartialEq, Hash)]
2846pub enum ElementId {
2847    View(EntityId),
2848    Integer(usize),
2849    Name(SharedString),
2850    FocusHandle(FocusId),
2851    NamedInteger(SharedString, usize),
2852}
2853
2854impl ElementId {
2855    pub(crate) fn from_entity_id(entity_id: EntityId) -> Self {
2856        ElementId::View(entity_id)
2857    }
2858}
2859
2860impl TryInto<SharedString> for ElementId {
2861    type Error = anyhow::Error;
2862
2863    fn try_into(self) -> anyhow::Result<SharedString> {
2864        if let ElementId::Name(name) = self {
2865            Ok(name)
2866        } else {
2867            Err(anyhow!("element id is not string"))
2868        }
2869    }
2870}
2871
2872impl From<usize> for ElementId {
2873    fn from(id: usize) -> Self {
2874        ElementId::Integer(id)
2875    }
2876}
2877
2878impl From<i32> for ElementId {
2879    fn from(id: i32) -> Self {
2880        Self::Integer(id as usize)
2881    }
2882}
2883
2884impl From<SharedString> for ElementId {
2885    fn from(name: SharedString) -> Self {
2886        ElementId::Name(name)
2887    }
2888}
2889
2890impl From<&'static str> for ElementId {
2891    fn from(name: &'static str) -> Self {
2892        ElementId::Name(name.into())
2893    }
2894}
2895
2896impl<'a> From<&'a FocusHandle> for ElementId {
2897    fn from(handle: &'a FocusHandle) -> Self {
2898        ElementId::FocusHandle(handle.id)
2899    }
2900}
2901
2902impl From<(&'static str, EntityId)> for ElementId {
2903    fn from((name, id): (&'static str, EntityId)) -> Self {
2904        ElementId::NamedInteger(name.into(), id.as_u64() as usize)
2905    }
2906}
2907
2908impl From<(&'static str, usize)> for ElementId {
2909    fn from((name, id): (&'static str, usize)) -> Self {
2910        ElementId::NamedInteger(name.into(), id)
2911    }
2912}
2913
2914impl From<(&'static str, u64)> for ElementId {
2915    fn from((name, id): (&'static str, u64)) -> Self {
2916        ElementId::NamedInteger(name.into(), id as usize)
2917    }
2918}