window.rs

   1use crate::{
   2    key_dispatch::DispatchActionListener, px, size, transparent_black, Action, AnyDrag, AnyView,
   3    AppContext, AsyncWindowContext, AvailableSpace, Bounds, BoxShadow, Context, Corners,
   4    CursorStyle, DevicePixels, DispatchNodeId, DispatchTree, DisplayId, Edges, Effect, Entity,
   5    EntityId, EventEmitter, FileDropEvent, Flatten, FocusEvent, FontId, GlobalElementId, GlyphId,
   6    Hsla, ImageData, InputEvent, IsZero, KeyBinding, KeyContext, KeyDownEvent, KeystrokeEvent,
   7    LayoutId, Model, ModelContext, Modifiers, MonochromeSprite, MouseButton, MouseMoveEvent,
   8    MouseUpEvent, Path, Pixels, PlatformAtlas, PlatformDisplay, PlatformInputHandler,
   9    PlatformWindow, Point, PolychromeSprite, PromptLevel, Quad, Render, RenderGlyphParams,
  10    RenderImageParams, RenderSvgParams, ScaledPixels, Scene, SceneBuilder, Shadow, SharedString,
  11    Size, Style, SubscriberSet, Subscription, Surface, TaffyLayoutEngine, Task, Underline,
  12    UnderlineStyle, View, VisualContext, WeakView, WindowBounds, WindowOptions, SUBPIXEL_VARIANTS,
  13};
  14use anyhow::{anyhow, Context as _, Result};
  15use collections::FxHashMap;
  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: u8 = 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, Clone, Debug, Ord, PartialOrd, PartialEq, Eq)]
  46pub struct StackingOrder {
  47    #[deref]
  48    #[deref_mut]
  49    z_indices: SmallVec<[u8; 64]>,
  50}
  51
  52impl Default for StackingOrder {
  53    fn default() -> Self {
  54        StackingOrder {
  55            z_indices: SmallVec::new(),
  56        }
  57    }
  58}
  59
  60/// Represents the two different phases when dispatching events.
  61#[derive(Default, Copy, Clone, Debug, Eq, PartialEq)]
  62pub enum DispatchPhase {
  63    /// After the capture phase comes the bubble phase, in which mouse event listeners are
  64    /// invoked front to back and keyboard event listeners are invoked from the focused element
  65    /// to the root of the element tree. This is the phase you'll most commonly want to use when
  66    /// registering event listeners.
  67    #[default]
  68    Bubble,
  69    /// During the initial capture phase, mouse event listeners are invoked back to front, and keyboard
  70    /// listeners are invoked from the root of the tree downward toward the focused element. This phase
  71    /// is used for special purposes such as clearing the "pressed" state for click events. If
  72    /// you stop event propagation during this phase, you need to know what you're doing. Handlers
  73    /// outside of the immediate region may rely on detecting non-local events during this phase.
  74    Capture,
  75}
  76
  77impl DispatchPhase {
  78    pub fn bubble(self) -> bool {
  79        self == DispatchPhase::Bubble
  80    }
  81
  82    pub fn capture(self) -> bool {
  83        self == DispatchPhase::Capture
  84    }
  85}
  86
  87type AnyObserver = Box<dyn FnMut(&mut WindowContext) -> bool + 'static>;
  88type AnyMouseListener = Box<dyn FnMut(&dyn Any, DispatchPhase, &mut WindowContext) + 'static>;
  89type AnyFocusListener = Box<dyn Fn(&FocusEvent, &mut WindowContext) + 'static>;
  90type AnyWindowFocusListener = Box<dyn FnMut(&FocusEvent, &mut WindowContext) -> bool + 'static>;
  91
  92slotmap::new_key_type! { pub struct FocusId; }
  93
  94impl FocusId {
  95    /// Obtains whether the element associated with this handle is currently focused.
  96    pub fn is_focused(&self, cx: &WindowContext) -> bool {
  97        cx.window.focus == Some(*self)
  98    }
  99
 100    /// Obtains whether the element associated with this handle contains the focused
 101    /// element or is itself focused.
 102    pub fn contains_focused(&self, cx: &WindowContext) -> bool {
 103        cx.focused()
 104            .map_or(false, |focused| self.contains(focused.id, cx))
 105    }
 106
 107    /// Obtains whether the element associated with this handle is contained within the
 108    /// focused element or is itself focused.
 109    pub fn within_focused(&self, cx: &WindowContext) -> bool {
 110        let focused = cx.focused();
 111        focused.map_or(false, |focused| focused.id.contains(*self, cx))
 112    }
 113
 114    /// Obtains whether this handle contains the given handle in the most recently rendered frame.
 115    pub(crate) fn contains(&self, other: Self, cx: &WindowContext) -> bool {
 116        cx.window
 117            .rendered_frame
 118            .dispatch_tree
 119            .focus_contains(*self, other)
 120    }
 121}
 122
 123/// A handle which can be used to track and manipulate the focused element in a window.
 124pub struct FocusHandle {
 125    pub(crate) id: FocusId,
 126    handles: Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>,
 127}
 128
 129impl std::fmt::Debug for FocusHandle {
 130    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 131        f.write_fmt(format_args!("FocusHandle({:?})", self.id))
 132    }
 133}
 134
 135impl FocusHandle {
 136    pub(crate) fn new(handles: &Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>) -> Self {
 137        let id = handles.write().insert(AtomicUsize::new(1));
 138        Self {
 139            id,
 140            handles: handles.clone(),
 141        }
 142    }
 143
 144    pub(crate) fn for_id(
 145        id: FocusId,
 146        handles: &Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>,
 147    ) -> Option<Self> {
 148        let lock = handles.read();
 149        let ref_count = lock.get(id)?;
 150        if ref_count.load(SeqCst) == 0 {
 151            None
 152        } else {
 153            ref_count.fetch_add(1, SeqCst);
 154            Some(Self {
 155                id,
 156                handles: handles.clone(),
 157            })
 158        }
 159    }
 160
 161    /// Moves the focus to the element associated with this handle.
 162    pub fn focus(&self, cx: &mut WindowContext) {
 163        cx.focus(self)
 164    }
 165
 166    /// Obtains whether the element associated with this handle is currently focused.
 167    pub fn is_focused(&self, cx: &WindowContext) -> bool {
 168        self.id.is_focused(cx)
 169    }
 170
 171    /// Obtains whether the element associated with this handle contains the focused
 172    /// element or is itself focused.
 173    pub fn contains_focused(&self, cx: &WindowContext) -> bool {
 174        self.id.contains_focused(cx)
 175    }
 176
 177    /// Obtains whether the element associated with this handle is contained within the
 178    /// focused element or is itself focused.
 179    pub fn within_focused(&self, cx: &WindowContext) -> bool {
 180        self.id.within_focused(cx)
 181    }
 182
 183    /// Obtains whether this handle contains the given handle in the most recently rendered frame.
 184    pub fn contains(&self, other: &Self, cx: &WindowContext) -> bool {
 185        self.id.contains(other.id, cx)
 186    }
 187}
 188
 189impl Clone for FocusHandle {
 190    fn clone(&self) -> Self {
 191        Self::for_id(self.id, &self.handles).unwrap()
 192    }
 193}
 194
 195impl PartialEq for FocusHandle {
 196    fn eq(&self, other: &Self) -> bool {
 197        self.id == other.id
 198    }
 199}
 200
 201impl Eq for FocusHandle {}
 202
 203impl Drop for FocusHandle {
 204    fn drop(&mut self) {
 205        self.handles
 206            .read()
 207            .get(self.id)
 208            .unwrap()
 209            .fetch_sub(1, SeqCst);
 210    }
 211}
 212
 213/// FocusableView allows users of your view to easily
 214/// focus it (using cx.focus_view(view))
 215pub trait FocusableView: 'static + Render {
 216    fn focus_handle(&self, cx: &AppContext) -> FocusHandle;
 217}
 218
 219/// ManagedView is a view (like a Modal, Popover, Menu, etc.)
 220/// where the lifecycle of the view is handled by another view.
 221pub trait ManagedView: FocusableView + EventEmitter<DismissEvent> {}
 222
 223impl<M: FocusableView + EventEmitter<DismissEvent>> ManagedView for M {}
 224
 225pub struct DismissEvent;
 226
 227// Holds the state for a specific window.
 228pub struct Window {
 229    pub(crate) handle: AnyWindowHandle,
 230    pub(crate) removed: bool,
 231    pub(crate) platform_window: Box<dyn PlatformWindow>,
 232    display_id: DisplayId,
 233    sprite_atlas: Arc<dyn PlatformAtlas>,
 234    rem_size: Pixels,
 235    viewport_size: Size<Pixels>,
 236    layout_engine: Option<TaffyLayoutEngine>,
 237    pub(crate) root_view: Option<AnyView>,
 238    pub(crate) element_id_stack: GlobalElementId,
 239    pub(crate) rendered_frame: Frame,
 240    pub(crate) next_frame: Frame,
 241    pub(crate) focus_handles: Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>,
 242    pub(crate) focus_listeners: SubscriberSet<(), AnyWindowFocusListener>,
 243    pub(crate) blur_listeners: SubscriberSet<(), AnyObserver>,
 244    default_prevented: bool,
 245    mouse_position: Point<Pixels>,
 246    modifiers: Modifiers,
 247    requested_cursor_style: Option<CursorStyle>,
 248    scale_factor: f32,
 249    bounds: WindowBounds,
 250    bounds_observers: SubscriberSet<(), AnyObserver>,
 251    active: bool,
 252    pub(crate) dirty: bool,
 253    pub(crate) drawing: bool,
 254    activation_observers: SubscriberSet<(), AnyObserver>,
 255    pub(crate) last_blur: Option<Option<FocusId>>,
 256    pub(crate) focus: Option<FocusId>,
 257}
 258
 259pub(crate) struct ElementStateBox {
 260    inner: Box<dyn Any>,
 261    #[cfg(debug_assertions)]
 262    type_name: &'static str,
 263}
 264
 265// #[derive(Default)]
 266pub(crate) struct Frame {
 267    pub(crate) element_states: FxHashMap<GlobalElementId, ElementStateBox>,
 268    mouse_listeners: FxHashMap<TypeId, Vec<(StackingOrder, AnyMouseListener)>>,
 269    pub(crate) dispatch_tree: DispatchTree,
 270    pub(crate) focus_listeners: Vec<AnyFocusListener>,
 271    pub(crate) scene_builder: SceneBuilder,
 272    pub(crate) depth_map: Vec<(StackingOrder, Bounds<Pixels>)>,
 273    pub(crate) z_index_stack: StackingOrder,
 274    content_mask_stack: Vec<ContentMask<Pixels>>,
 275    element_offset_stack: Vec<Point<Pixels>>,
 276}
 277
 278impl Frame {
 279    fn new(dispatch_tree: DispatchTree) -> Self {
 280        Frame {
 281            element_states: FxHashMap::default(),
 282            mouse_listeners: FxHashMap::default(),
 283            dispatch_tree,
 284            focus_listeners: Vec::new(),
 285            scene_builder: SceneBuilder::default(),
 286            z_index_stack: StackingOrder::default(),
 287            depth_map: Default::default(),
 288            content_mask_stack: Vec::new(),
 289            element_offset_stack: Vec::new(),
 290        }
 291    }
 292
 293    fn clear(&mut self) {
 294        self.element_states.clear();
 295        self.mouse_listeners.values_mut().for_each(Vec::clear);
 296        self.focus_listeners.clear();
 297        self.dispatch_tree.clear();
 298        self.depth_map.clear();
 299    }
 300}
 301
 302impl Window {
 303    pub(crate) fn new(
 304        handle: AnyWindowHandle,
 305        options: WindowOptions,
 306        cx: &mut AppContext,
 307    ) -> Self {
 308        let platform_window = cx.platform.open_window(
 309            handle,
 310            options,
 311            Box::new({
 312                let mut cx = cx.to_async();
 313                move || handle.update(&mut cx, |_, cx| cx.draw())
 314            }),
 315        );
 316        let display_id = platform_window.display().id();
 317        let sprite_atlas = platform_window.sprite_atlas();
 318        let mouse_position = platform_window.mouse_position();
 319        let modifiers = platform_window.modifiers();
 320        let content_size = platform_window.content_size();
 321        let scale_factor = platform_window.scale_factor();
 322        let bounds = platform_window.bounds();
 323
 324        platform_window.on_resize(Box::new({
 325            let mut cx = cx.to_async();
 326            move |_, _| {
 327                handle
 328                    .update(&mut cx, |_, cx| cx.window_bounds_changed())
 329                    .log_err();
 330            }
 331        }));
 332        platform_window.on_moved(Box::new({
 333            let mut cx = cx.to_async();
 334            move || {
 335                handle
 336                    .update(&mut cx, |_, cx| cx.window_bounds_changed())
 337                    .log_err();
 338            }
 339        }));
 340        platform_window.on_active_status_change(Box::new({
 341            let mut cx = cx.to_async();
 342            move |active| {
 343                handle
 344                    .update(&mut cx, |_, cx| {
 345                        cx.window.active = active;
 346                        cx.window
 347                            .activation_observers
 348                            .clone()
 349                            .retain(&(), |callback| callback(cx));
 350                    })
 351                    .log_err();
 352            }
 353        }));
 354
 355        platform_window.on_input({
 356            let mut cx = cx.to_async();
 357            Box::new(move |event| {
 358                handle
 359                    .update(&mut cx, |_, cx| cx.dispatch_event(event))
 360                    .log_err()
 361                    .unwrap_or(false)
 362            })
 363        });
 364
 365        Window {
 366            handle,
 367            removed: false,
 368            platform_window,
 369            display_id,
 370            sprite_atlas,
 371            rem_size: px(16.),
 372            viewport_size: content_size,
 373            layout_engine: Some(TaffyLayoutEngine::new()),
 374            root_view: None,
 375            element_id_stack: GlobalElementId::default(),
 376            rendered_frame: Frame::new(DispatchTree::new(cx.keymap.clone(), cx.actions.clone())),
 377            next_frame: Frame::new(DispatchTree::new(cx.keymap.clone(), cx.actions.clone())),
 378            focus_handles: Arc::new(RwLock::new(SlotMap::with_key())),
 379            focus_listeners: SubscriberSet::new(),
 380            blur_listeners: SubscriberSet::new(),
 381            default_prevented: true,
 382            mouse_position,
 383            modifiers,
 384            requested_cursor_style: None,
 385            scale_factor,
 386            bounds,
 387            bounds_observers: SubscriberSet::new(),
 388            active: false,
 389            dirty: false,
 390            drawing: false,
 391            activation_observers: SubscriberSet::new(),
 392            last_blur: None,
 393            focus: None,
 394        }
 395    }
 396}
 397
 398/// Indicates which region of the window is visible. Content falling outside of this mask will not be
 399/// rendered. Currently, only rectangular content masks are supported, but we give the mask its own type
 400/// to leave room to support more complex shapes in the future.
 401#[derive(Clone, Debug, Default, PartialEq, Eq)]
 402#[repr(C)]
 403pub struct ContentMask<P: Clone + Default + Debug> {
 404    pub bounds: Bounds<P>,
 405}
 406
 407impl ContentMask<Pixels> {
 408    /// Scale the content mask's pixel units by the given scaling factor.
 409    pub fn scale(&self, factor: f32) -> ContentMask<ScaledPixels> {
 410        ContentMask {
 411            bounds: self.bounds.scale(factor),
 412        }
 413    }
 414
 415    /// Intersect the content mask with the given content mask.
 416    pub fn intersect(&self, other: &Self) -> Self {
 417        let bounds = self.bounds.intersect(&other.bounds);
 418        ContentMask { bounds }
 419    }
 420}
 421
 422/// Provides access to application state in the context of a single window. Derefs
 423/// to an `AppContext`, so you can also pass a `WindowContext` to any method that takes
 424/// an `AppContext` and call any `AppContext` methods.
 425pub struct WindowContext<'a> {
 426    pub(crate) app: &'a mut AppContext,
 427    pub(crate) window: &'a mut Window,
 428}
 429
 430impl<'a> WindowContext<'a> {
 431    pub(crate) fn new(app: &'a mut AppContext, window: &'a mut Window) -> Self {
 432        Self { app, window }
 433    }
 434
 435    /// Obtain a handle to the window that belongs to this context.
 436    pub fn window_handle(&self) -> AnyWindowHandle {
 437        self.window.handle
 438    }
 439
 440    /// Mark the window as dirty, scheduling it to be redrawn on the next frame.
 441    pub fn notify(&mut self) {
 442        if !self.window.drawing {
 443            self.window.dirty = true;
 444        }
 445    }
 446
 447    /// Close this window.
 448    pub fn remove_window(&mut self) {
 449        self.window.removed = true;
 450    }
 451
 452    /// Obtain a new `FocusHandle`, which allows you to track and manipulate the keyboard focus
 453    /// for elements rendered within this window.
 454    pub fn focus_handle(&mut self) -> FocusHandle {
 455        FocusHandle::new(&self.window.focus_handles)
 456    }
 457
 458    /// Obtain the currently focused `FocusHandle`. If no elements are focused, returns `None`.
 459    pub fn focused(&self) -> Option<FocusHandle> {
 460        self.window
 461            .focus
 462            .and_then(|id| FocusHandle::for_id(id, &self.window.focus_handles))
 463    }
 464
 465    /// Move focus to the element associated with the given `FocusHandle`.
 466    pub fn focus(&mut self, handle: &FocusHandle) {
 467        if self.window.focus == Some(handle.id) {
 468            return;
 469        }
 470
 471        let focus_id = handle.id;
 472
 473        if self.window.last_blur.is_none() {
 474            self.window.last_blur = Some(self.window.focus);
 475        }
 476
 477        self.window.focus = Some(focus_id);
 478        self.window
 479            .rendered_frame
 480            .dispatch_tree
 481            .clear_pending_keystrokes();
 482        self.app.push_effect(Effect::FocusChanged {
 483            window_handle: self.window.handle,
 484            focused: Some(focus_id),
 485        });
 486        self.notify();
 487    }
 488
 489    /// Remove focus from all elements within this context's window.
 490    pub fn blur(&mut self) {
 491        if self.window.last_blur.is_none() {
 492            self.window.last_blur = Some(self.window.focus);
 493        }
 494
 495        self.window.focus = None;
 496        self.app.push_effect(Effect::FocusChanged {
 497            window_handle: self.window.handle,
 498            focused: None,
 499        });
 500        self.notify();
 501    }
 502
 503    pub fn dispatch_action(&mut self, action: Box<dyn Action>) {
 504        let focus_handle = self.focused();
 505
 506        self.defer(move |cx| {
 507            let node_id = focus_handle
 508                .and_then(|handle| {
 509                    cx.window
 510                        .rendered_frame
 511                        .dispatch_tree
 512                        .focusable_node_id(handle.id)
 513                })
 514                .unwrap_or_else(|| cx.window.rendered_frame.dispatch_tree.root_node_id());
 515
 516            cx.propagate_event = true;
 517            cx.dispatch_action_on_node(node_id, action);
 518        })
 519    }
 520
 521    pub(crate) fn dispatch_keystroke_observers(
 522        &mut self,
 523        event: &dyn Any,
 524        action: Option<Box<dyn Action>>,
 525    ) {
 526        let Some(key_down_event) = event.downcast_ref::<KeyDownEvent>() else {
 527            return;
 528        };
 529
 530        self.keystroke_observers
 531            .clone()
 532            .retain(&(), move |callback| {
 533                (callback)(
 534                    &KeystrokeEvent {
 535                        keystroke: key_down_event.keystroke.clone(),
 536                        action: action.as_ref().map(|action| action.boxed_clone()),
 537                    },
 538                    self,
 539                );
 540                true
 541            });
 542    }
 543
 544    /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
 545    /// that are currently on the stack to be returned to the app.
 546    pub fn defer(&mut self, f: impl FnOnce(&mut WindowContext) + 'static) {
 547        let handle = self.window.handle;
 548        self.app.defer(move |cx| {
 549            handle.update(cx, |_, cx| f(cx)).ok();
 550        });
 551    }
 552
 553    pub fn subscribe<Emitter, E, Evt>(
 554        &mut self,
 555        entity: &E,
 556        mut on_event: impl FnMut(E, &Evt, &mut WindowContext<'_>) + 'static,
 557    ) -> Subscription
 558    where
 559        Emitter: EventEmitter<Evt>,
 560        E: Entity<Emitter>,
 561        Evt: 'static,
 562    {
 563        let entity_id = entity.entity_id();
 564        let entity = entity.downgrade();
 565        let window_handle = self.window.handle;
 566        let (subscription, activate) = self.app.event_listeners.insert(
 567            entity_id,
 568            (
 569                TypeId::of::<Evt>(),
 570                Box::new(move |event, cx| {
 571                    window_handle
 572                        .update(cx, |_, cx| {
 573                            if let Some(handle) = E::upgrade_from(&entity) {
 574                                let event = event.downcast_ref().expect("invalid event type");
 575                                on_event(handle, event, cx);
 576                                true
 577                            } else {
 578                                false
 579                            }
 580                        })
 581                        .unwrap_or(false)
 582                }),
 583            ),
 584        );
 585        self.app.defer(move |_| activate());
 586        subscription
 587    }
 588
 589    /// Create an `AsyncWindowContext`, which has a static lifetime and can be held across
 590    /// await points in async code.
 591    pub fn to_async(&self) -> AsyncWindowContext {
 592        AsyncWindowContext::new(self.app.to_async(), self.window.handle)
 593    }
 594
 595    /// Schedule the given closure to be run directly after the current frame is rendered.
 596    pub fn on_next_frame(&mut self, callback: impl FnOnce(&mut WindowContext) + 'static) {
 597        let handle = self.window.handle;
 598        let display_id = self.window.display_id;
 599
 600        if !self.frame_consumers.contains_key(&display_id) {
 601            let (tx, mut rx) = mpsc::unbounded::<()>();
 602            self.platform.set_display_link_output_callback(
 603                display_id,
 604                Box::new(move |_current_time, _output_time| _ = tx.unbounded_send(())),
 605            );
 606
 607            let consumer_task = self.app.spawn(|cx| async move {
 608                while rx.next().await.is_some() {
 609                    cx.update(|cx| {
 610                        for callback in cx
 611                            .next_frame_callbacks
 612                            .get_mut(&display_id)
 613                            .unwrap()
 614                            .drain(..)
 615                            .collect::<SmallVec<[_; 32]>>()
 616                        {
 617                            callback(cx);
 618                        }
 619                    })
 620                    .ok();
 621
 622                    // Flush effects, then stop the display link if no new next_frame_callbacks have been added.
 623
 624                    cx.update(|cx| {
 625                        if cx.next_frame_callbacks.is_empty() {
 626                            cx.platform.stop_display_link(display_id);
 627                        }
 628                    })
 629                    .ok();
 630                }
 631            });
 632            self.frame_consumers.insert(display_id, consumer_task);
 633        }
 634
 635        if self.next_frame_callbacks.is_empty() {
 636            self.platform.start_display_link(display_id);
 637        }
 638
 639        self.next_frame_callbacks
 640            .entry(display_id)
 641            .or_default()
 642            .push(Box::new(move |cx: &mut AppContext| {
 643                cx.update_window(handle, |_root_view, cx| callback(cx)).ok();
 644            }));
 645    }
 646
 647    /// Spawn the future returned by the given closure on the application thread pool.
 648    /// The closure is provided a handle to the current window and an `AsyncWindowContext` for
 649    /// use within your future.
 650    pub fn spawn<Fut, R>(&mut self, f: impl FnOnce(AsyncWindowContext) -> Fut) -> Task<R>
 651    where
 652        R: 'static,
 653        Fut: Future<Output = R> + 'static,
 654    {
 655        self.app
 656            .spawn(|app| f(AsyncWindowContext::new(app, self.window.handle)))
 657    }
 658
 659    /// Update the global of the given type. The given closure is given simultaneous mutable
 660    /// access both to the global and the context.
 661    pub fn update_global<G, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R
 662    where
 663        G: 'static,
 664    {
 665        let mut global = self.app.lease_global::<G>();
 666        let result = f(&mut global, self);
 667        self.app.end_global_lease(global);
 668        result
 669    }
 670
 671    #[must_use]
 672    /// Add a node to the layout tree for the current frame. Takes the `Style` of the element for which
 673    /// layout is being requested, along with the layout ids of any children. This method is called during
 674    /// calls to the `Element::layout` trait method and enables any element to participate in layout.
 675    pub fn request_layout(
 676        &mut self,
 677        style: &Style,
 678        children: impl IntoIterator<Item = LayoutId>,
 679    ) -> LayoutId {
 680        self.app.layout_id_buffer.clear();
 681        self.app.layout_id_buffer.extend(children.into_iter());
 682        let rem_size = self.rem_size();
 683
 684        self.window.layout_engine.as_mut().unwrap().request_layout(
 685            style,
 686            rem_size,
 687            &self.app.layout_id_buffer,
 688        )
 689    }
 690
 691    /// Add a node to the layout tree for the current frame. Instead of taking a `Style` and children,
 692    /// this variant takes a function that is invoked during layout so you can use arbitrary logic to
 693    /// determine the element's size. One place this is used internally is when measuring text.
 694    ///
 695    /// The given closure is invoked at layout time with the known dimensions and available space and
 696    /// returns a `Size`.
 697    pub fn request_measured_layout<
 698        F: FnMut(Size<Option<Pixels>>, Size<AvailableSpace>, &mut WindowContext) -> Size<Pixels>
 699            + 'static,
 700    >(
 701        &mut self,
 702        style: Style,
 703        measure: F,
 704    ) -> LayoutId {
 705        let rem_size = self.rem_size();
 706        self.window
 707            .layout_engine
 708            .as_mut()
 709            .unwrap()
 710            .request_measured_layout(style, rem_size, measure)
 711    }
 712
 713    pub fn compute_layout(&mut self, layout_id: LayoutId, available_space: Size<AvailableSpace>) {
 714        let mut layout_engine = self.window.layout_engine.take().unwrap();
 715        layout_engine.compute_layout(layout_id, available_space, self);
 716        self.window.layout_engine = Some(layout_engine);
 717    }
 718
 719    /// Obtain the bounds computed for the given LayoutId relative to the window. This method should not
 720    /// be invoked until the paint phase begins, and will usually be invoked by GPUI itself automatically
 721    /// in order to pass your element its `Bounds` automatically.
 722    pub fn layout_bounds(&mut self, layout_id: LayoutId) -> Bounds<Pixels> {
 723        let mut bounds = self
 724            .window
 725            .layout_engine
 726            .as_mut()
 727            .unwrap()
 728            .layout_bounds(layout_id)
 729            .map(Into::into);
 730        bounds.origin += self.element_offset();
 731        bounds
 732    }
 733
 734    fn window_bounds_changed(&mut self) {
 735        self.window.scale_factor = self.window.platform_window.scale_factor();
 736        self.window.viewport_size = self.window.platform_window.content_size();
 737        self.window.bounds = self.window.platform_window.bounds();
 738        self.window.display_id = self.window.platform_window.display().id();
 739        self.notify();
 740
 741        self.window
 742            .bounds_observers
 743            .clone()
 744            .retain(&(), |callback| callback(self));
 745    }
 746
 747    pub fn window_bounds(&self) -> WindowBounds {
 748        self.window.bounds
 749    }
 750
 751    pub fn viewport_size(&self) -> Size<Pixels> {
 752        self.window.viewport_size
 753    }
 754
 755    pub fn is_window_active(&self) -> bool {
 756        self.window.active
 757    }
 758
 759    pub fn zoom_window(&self) {
 760        self.window.platform_window.zoom();
 761    }
 762
 763    pub fn set_window_title(&mut self, title: &str) {
 764        self.window.platform_window.set_title(title);
 765    }
 766
 767    pub fn display(&self) -> Option<Rc<dyn PlatformDisplay>> {
 768        self.platform
 769            .displays()
 770            .into_iter()
 771            .find(|display| display.id() == self.window.display_id)
 772    }
 773
 774    pub fn show_character_palette(&self) {
 775        self.window.platform_window.show_character_palette();
 776    }
 777
 778    /// The scale factor of the display associated with the window. For example, it could
 779    /// return 2.0 for a "retina" display, indicating that each logical pixel should actually
 780    /// be rendered as two pixels on screen.
 781    pub fn scale_factor(&self) -> f32 {
 782        self.window.scale_factor
 783    }
 784
 785    /// The size of an em for the base font of the application. Adjusting this value allows the
 786    /// UI to scale, just like zooming a web page.
 787    pub fn rem_size(&self) -> Pixels {
 788        self.window.rem_size
 789    }
 790
 791    /// Sets the size of an em for the base font of the application. Adjusting this value allows the
 792    /// UI to scale, just like zooming a web page.
 793    pub fn set_rem_size(&mut self, rem_size: impl Into<Pixels>) {
 794        self.window.rem_size = rem_size.into();
 795    }
 796
 797    /// The line height associated with the current text style.
 798    pub fn line_height(&self) -> Pixels {
 799        let rem_size = self.rem_size();
 800        let text_style = self.text_style();
 801        text_style
 802            .line_height
 803            .to_pixels(text_style.font_size.into(), rem_size)
 804    }
 805
 806    /// Call to prevent the default action of an event. Currently only used to prevent
 807    /// parent elements from becoming focused on mouse down.
 808    pub fn prevent_default(&mut self) {
 809        self.window.default_prevented = true;
 810    }
 811
 812    /// Obtain whether default has been prevented for the event currently being dispatched.
 813    pub fn default_prevented(&self) -> bool {
 814        self.window.default_prevented
 815    }
 816
 817    /// Register a mouse event listener on the window for the next frame. The type of event
 818    /// is determined by the first parameter of the given listener. When the next frame is rendered
 819    /// the listener will be cleared.
 820    ///
 821    /// This is a fairly low-level method, so prefer using event handlers on elements unless you have
 822    /// a specific need to register a global listener.
 823    pub fn on_mouse_event<Event: 'static>(
 824        &mut self,
 825        mut handler: impl FnMut(&Event, DispatchPhase, &mut WindowContext) + 'static,
 826    ) {
 827        let order = self.window.next_frame.z_index_stack.clone();
 828        self.window
 829            .next_frame
 830            .mouse_listeners
 831            .entry(TypeId::of::<Event>())
 832            .or_default()
 833            .push((
 834                order,
 835                Box::new(move |event: &dyn Any, phase, cx| {
 836                    handler(event.downcast_ref().unwrap(), phase, cx)
 837                }),
 838            ))
 839    }
 840
 841    /// Register a key event listener on the window for the next frame. The type of event
 842    /// is determined by the first parameter of the given listener. When the next frame is rendered
 843    /// the listener will be cleared.
 844    ///
 845    /// This is a fairly low-level method, so prefer using event handlers on elements unless you have
 846    /// a specific need to register a global listener.
 847    pub fn on_key_event<Event: 'static>(
 848        &mut self,
 849        handler: impl Fn(&Event, DispatchPhase, &mut WindowContext) + 'static,
 850    ) {
 851        self.window
 852            .next_frame
 853            .dispatch_tree
 854            .on_key_event(Rc::new(move |event, phase, cx| {
 855                if let Some(event) = event.downcast_ref::<Event>() {
 856                    handler(event, phase, cx)
 857                }
 858            }));
 859    }
 860
 861    /// Register an action listener on the window for the next frame. The type of action
 862    /// is determined by the first parameter of the given listener. When the next frame is rendered
 863    /// the listener will be cleared.
 864    ///
 865    /// This is a fairly low-level method, so prefer using action handlers on elements unless you have
 866    /// a specific need to register a global listener.
 867    pub fn on_action(
 868        &mut self,
 869        action_type: TypeId,
 870        handler: impl Fn(&dyn Any, DispatchPhase, &mut WindowContext) + 'static,
 871    ) {
 872        self.window.next_frame.dispatch_tree.on_action(
 873            action_type,
 874            Rc::new(move |action, phase, cx| handler(action, phase, cx)),
 875        );
 876    }
 877
 878    pub fn is_action_available(&self, action: &dyn Action) -> bool {
 879        let target = self
 880            .focused()
 881            .and_then(|focused_handle| {
 882                self.window
 883                    .rendered_frame
 884                    .dispatch_tree
 885                    .focusable_node_id(focused_handle.id)
 886            })
 887            .unwrap_or_else(|| self.window.rendered_frame.dispatch_tree.root_node_id());
 888        self.window
 889            .rendered_frame
 890            .dispatch_tree
 891            .is_action_available(action, target)
 892    }
 893
 894    /// The position of the mouse relative to the window.
 895    pub fn mouse_position(&self) -> Point<Pixels> {
 896        self.window.mouse_position
 897    }
 898
 899    /// The current state of the keyboard's modifiers
 900    pub fn modifiers(&self) -> Modifiers {
 901        self.window.modifiers
 902    }
 903
 904    pub fn set_cursor_style(&mut self, style: CursorStyle) {
 905        self.window.requested_cursor_style = Some(style)
 906    }
 907
 908    /// Called during painting to invoke the given closure in a new stacking context. The given
 909    /// z-index is interpreted relative to the previous call to `stack`.
 910    pub fn with_z_index<R>(&mut self, z_index: u8, f: impl FnOnce(&mut Self) -> R) -> R {
 911        self.window.next_frame.z_index_stack.push(z_index);
 912        let result = f(self);
 913        self.window.next_frame.z_index_stack.pop();
 914        result
 915    }
 916
 917    /// Called during painting to track which z-index is on top at each pixel position
 918    pub fn add_opaque_layer(&mut self, bounds: Bounds<Pixels>) {
 919        let stacking_order = self.window.next_frame.z_index_stack.clone();
 920        let depth_map = &mut self.window.next_frame.depth_map;
 921        match depth_map.binary_search_by(|(level, _)| stacking_order.cmp(&level)) {
 922            Ok(i) | Err(i) => depth_map.insert(i, (stacking_order, bounds)),
 923        }
 924    }
 925
 926    /// Returns true if the top-most opaque layer painted over this point was part of the
 927    /// same layer as the given stacking order.
 928    pub fn was_top_layer(&self, point: &Point<Pixels>, level: &StackingOrder) -> bool {
 929        for (stack, bounds) in self.window.rendered_frame.depth_map.iter() {
 930            if bounds.contains(point) {
 931                return level.starts_with(stack) || stack.starts_with(level);
 932            }
 933        }
 934
 935        false
 936    }
 937
 938    pub fn was_top_layer_under_active_drag(
 939        &self,
 940        point: &Point<Pixels>,
 941        level: &StackingOrder,
 942    ) -> bool {
 943        for (stack, bounds) in self.window.rendered_frame.depth_map.iter() {
 944            if stack.starts_with(&[ACTIVE_DRAG_Z_INDEX]) {
 945                continue;
 946            }
 947            if bounds.contains(point) {
 948                return level.starts_with(stack) || stack.starts_with(level);
 949            }
 950        }
 951
 952        false
 953    }
 954
 955    /// Called during painting to get the current stacking order.
 956    pub fn stacking_order(&self) -> &StackingOrder {
 957        &self.window.next_frame.z_index_stack
 958    }
 959
 960    /// Paint one or more drop shadows into the scene for the next frame at the current z-index.
 961    pub fn paint_shadows(
 962        &mut self,
 963        bounds: Bounds<Pixels>,
 964        corner_radii: Corners<Pixels>,
 965        shadows: &[BoxShadow],
 966    ) {
 967        let scale_factor = self.scale_factor();
 968        let content_mask = self.content_mask();
 969        let window = &mut *self.window;
 970        for shadow in shadows {
 971            let mut shadow_bounds = bounds;
 972            shadow_bounds.origin += shadow.offset;
 973            shadow_bounds.dilate(shadow.spread_radius);
 974            window.next_frame.scene_builder.insert(
 975                &window.next_frame.z_index_stack,
 976                Shadow {
 977                    order: 0,
 978                    bounds: shadow_bounds.scale(scale_factor),
 979                    content_mask: content_mask.scale(scale_factor),
 980                    corner_radii: corner_radii.scale(scale_factor),
 981                    color: shadow.color,
 982                    blur_radius: shadow.blur_radius.scale(scale_factor),
 983                },
 984            );
 985        }
 986    }
 987
 988    /// Paint one or more quads into the scene for the next frame at the current stacking context.
 989    /// Quads are colored rectangular regions with an optional background, border, and corner radius.
 990    /// see [`fill`], [`outline`], and [`quad`] to construct this type.
 991    pub fn paint_quad(&mut self, quad: PaintQuad) {
 992        let scale_factor = self.scale_factor();
 993        let content_mask = self.content_mask();
 994
 995        let window = &mut *self.window;
 996        window.next_frame.scene_builder.insert(
 997            &window.next_frame.z_index_stack,
 998            Quad {
 999                order: 0,
1000                bounds: quad.bounds.scale(scale_factor),
1001                content_mask: content_mask.scale(scale_factor),
1002                background: quad.background,
1003                border_color: quad.border_color,
1004                corner_radii: quad.corner_radii.scale(scale_factor),
1005                border_widths: quad.border_widths.scale(scale_factor),
1006            },
1007        );
1008    }
1009
1010    /// Paint the given `Path` into the scene for the next frame at the current z-index.
1011    pub fn paint_path(&mut self, mut path: Path<Pixels>, color: impl Into<Hsla>) {
1012        let scale_factor = self.scale_factor();
1013        let content_mask = self.content_mask();
1014        path.content_mask = content_mask;
1015        path.color = color.into();
1016        let window = &mut *self.window;
1017        window
1018            .next_frame
1019            .scene_builder
1020            .insert(&window.next_frame.z_index_stack, path.scale(scale_factor));
1021    }
1022
1023    /// Paint an underline into the scene for the next frame at the current z-index.
1024    pub fn paint_underline(
1025        &mut self,
1026        origin: Point<Pixels>,
1027        width: Pixels,
1028        style: &UnderlineStyle,
1029    ) {
1030        let scale_factor = self.scale_factor();
1031        let height = if style.wavy {
1032            style.thickness * 3.
1033        } else {
1034            style.thickness
1035        };
1036        let bounds = Bounds {
1037            origin,
1038            size: size(width, height),
1039        };
1040        let content_mask = self.content_mask();
1041        let window = &mut *self.window;
1042        window.next_frame.scene_builder.insert(
1043            &window.next_frame.z_index_stack,
1044            Underline {
1045                order: 0,
1046                bounds: bounds.scale(scale_factor),
1047                content_mask: content_mask.scale(scale_factor),
1048                thickness: style.thickness.scale(scale_factor),
1049                color: style.color.unwrap_or_default(),
1050                wavy: style.wavy,
1051            },
1052        );
1053    }
1054
1055    /// Paint a monochrome (non-emoji) glyph into the scene for the next frame at the current z-index.
1056    /// The y component of the origin is the baseline of the glyph.
1057    pub fn paint_glyph(
1058        &mut self,
1059        origin: Point<Pixels>,
1060        font_id: FontId,
1061        glyph_id: GlyphId,
1062        font_size: Pixels,
1063        color: Hsla,
1064    ) -> Result<()> {
1065        let scale_factor = self.scale_factor();
1066        let glyph_origin = origin.scale(scale_factor);
1067        let subpixel_variant = Point {
1068            x: (glyph_origin.x.0.fract() * SUBPIXEL_VARIANTS as f32).floor() as u8,
1069            y: (glyph_origin.y.0.fract() * SUBPIXEL_VARIANTS as f32).floor() as u8,
1070        };
1071        let params = RenderGlyphParams {
1072            font_id,
1073            glyph_id,
1074            font_size,
1075            subpixel_variant,
1076            scale_factor,
1077            is_emoji: false,
1078        };
1079
1080        let raster_bounds = self.text_system().raster_bounds(&params)?;
1081        if !raster_bounds.is_zero() {
1082            let tile =
1083                self.window
1084                    .sprite_atlas
1085                    .get_or_insert_with(&params.clone().into(), &mut || {
1086                        let (size, bytes) = self.text_system().rasterize_glyph(&params)?;
1087                        Ok((size, Cow::Owned(bytes)))
1088                    })?;
1089            let bounds = Bounds {
1090                origin: glyph_origin.map(|px| px.floor()) + raster_bounds.origin.map(Into::into),
1091                size: tile.bounds.size.map(Into::into),
1092            };
1093            let content_mask = self.content_mask().scale(scale_factor);
1094            let window = &mut *self.window;
1095            window.next_frame.scene_builder.insert(
1096                &window.next_frame.z_index_stack,
1097                MonochromeSprite {
1098                    order: 0,
1099                    bounds,
1100                    content_mask,
1101                    color,
1102                    tile,
1103                },
1104            );
1105        }
1106        Ok(())
1107    }
1108
1109    /// Paint an emoji glyph into the scene for the next frame at the current z-index.
1110    /// The y component of the origin is the baseline of the glyph.
1111    pub fn paint_emoji(
1112        &mut self,
1113        origin: Point<Pixels>,
1114        font_id: FontId,
1115        glyph_id: GlyphId,
1116        font_size: Pixels,
1117    ) -> Result<()> {
1118        let scale_factor = self.scale_factor();
1119        let glyph_origin = origin.scale(scale_factor);
1120        let params = RenderGlyphParams {
1121            font_id,
1122            glyph_id,
1123            font_size,
1124            // We don't render emojis with subpixel variants.
1125            subpixel_variant: Default::default(),
1126            scale_factor,
1127            is_emoji: true,
1128        };
1129
1130        let raster_bounds = self.text_system().raster_bounds(&params)?;
1131        if !raster_bounds.is_zero() {
1132            let tile =
1133                self.window
1134                    .sprite_atlas
1135                    .get_or_insert_with(&params.clone().into(), &mut || {
1136                        let (size, bytes) = self.text_system().rasterize_glyph(&params)?;
1137                        Ok((size, Cow::Owned(bytes)))
1138                    })?;
1139            let bounds = Bounds {
1140                origin: glyph_origin.map(|px| px.floor()) + raster_bounds.origin.map(Into::into),
1141                size: tile.bounds.size.map(Into::into),
1142            };
1143            let content_mask = self.content_mask().scale(scale_factor);
1144            let window = &mut *self.window;
1145
1146            window.next_frame.scene_builder.insert(
1147                &window.next_frame.z_index_stack,
1148                PolychromeSprite {
1149                    order: 0,
1150                    bounds,
1151                    corner_radii: Default::default(),
1152                    content_mask,
1153                    tile,
1154                    grayscale: false,
1155                },
1156            );
1157        }
1158        Ok(())
1159    }
1160
1161    /// Paint a monochrome SVG into the scene for the next frame at the current stacking context.
1162    pub fn paint_svg(
1163        &mut self,
1164        bounds: Bounds<Pixels>,
1165        path: SharedString,
1166        color: Hsla,
1167    ) -> Result<()> {
1168        let scale_factor = self.scale_factor();
1169        let bounds = bounds.scale(scale_factor);
1170        // Render the SVG at twice the size to get a higher quality result.
1171        let params = RenderSvgParams {
1172            path,
1173            size: bounds
1174                .size
1175                .map(|pixels| DevicePixels::from((pixels.0 * 2.).ceil() as i32)),
1176        };
1177
1178        let tile =
1179            self.window
1180                .sprite_atlas
1181                .get_or_insert_with(&params.clone().into(), &mut || {
1182                    let bytes = self.svg_renderer.render(&params)?;
1183                    Ok((params.size, Cow::Owned(bytes)))
1184                })?;
1185        let content_mask = self.content_mask().scale(scale_factor);
1186
1187        let window = &mut *self.window;
1188        window.next_frame.scene_builder.insert(
1189            &window.next_frame.z_index_stack,
1190            MonochromeSprite {
1191                order: 0,
1192                bounds,
1193                content_mask,
1194                color,
1195                tile,
1196            },
1197        );
1198
1199        Ok(())
1200    }
1201
1202    /// Paint an image into the scene for the next frame at the current z-index.
1203    pub fn paint_image(
1204        &mut self,
1205        bounds: Bounds<Pixels>,
1206        corner_radii: Corners<Pixels>,
1207        data: Arc<ImageData>,
1208        grayscale: bool,
1209    ) -> Result<()> {
1210        let scale_factor = self.scale_factor();
1211        let bounds = bounds.scale(scale_factor);
1212        let params = RenderImageParams { image_id: data.id };
1213
1214        let tile = self
1215            .window
1216            .sprite_atlas
1217            .get_or_insert_with(&params.clone().into(), &mut || {
1218                Ok((data.size(), Cow::Borrowed(data.as_bytes())))
1219            })?;
1220        let content_mask = self.content_mask().scale(scale_factor);
1221        let corner_radii = corner_radii.scale(scale_factor);
1222
1223        let window = &mut *self.window;
1224        window.next_frame.scene_builder.insert(
1225            &window.next_frame.z_index_stack,
1226            PolychromeSprite {
1227                order: 0,
1228                bounds,
1229                content_mask,
1230                corner_radii,
1231                tile,
1232                grayscale,
1233            },
1234        );
1235        Ok(())
1236    }
1237
1238    /// Paint a surface into the scene for the next frame at the current z-index.
1239    pub fn paint_surface(&mut self, bounds: Bounds<Pixels>, image_buffer: CVImageBuffer) {
1240        let scale_factor = self.scale_factor();
1241        let bounds = bounds.scale(scale_factor);
1242        let content_mask = self.content_mask().scale(scale_factor);
1243        let window = &mut *self.window;
1244        window.next_frame.scene_builder.insert(
1245            &window.next_frame.z_index_stack,
1246            Surface {
1247                order: 0,
1248                bounds,
1249                content_mask,
1250                image_buffer,
1251            },
1252        );
1253    }
1254
1255    /// Draw pixels to the display for this window based on the contents of its scene.
1256    pub(crate) fn draw(&mut self) -> Scene {
1257        let t0 = std::time::Instant::now();
1258        self.window.dirty = false;
1259        self.window.drawing = true;
1260
1261        let window_was_focused = self
1262            .window
1263            .focus
1264            .and_then(|focus_id| {
1265                self.window
1266                    .rendered_frame
1267                    .dispatch_tree
1268                    .focusable_node_id(focus_id)
1269            })
1270            .is_some();
1271        self.text_system().start_frame();
1272        self.window.platform_window.clear_input_handler();
1273        self.window.layout_engine.as_mut().unwrap().clear();
1274        self.window.next_frame.clear();
1275        let root_view = self.window.root_view.take().unwrap();
1276
1277        self.with_z_index(0, |cx| {
1278            cx.with_key_dispatch(Some(KeyContext::default()), None, |_, cx| {
1279                for (action_type, action_listeners) in &cx.app.global_action_listeners {
1280                    for action_listener in action_listeners.iter().cloned() {
1281                        cx.window.next_frame.dispatch_tree.on_action(
1282                            *action_type,
1283                            Rc::new(move |action, phase, cx| action_listener(action, phase, cx)),
1284                        )
1285                    }
1286                }
1287
1288                let available_space = cx.window.viewport_size.map(Into::into);
1289                root_view.draw(Point::default(), available_space, cx);
1290            })
1291        });
1292
1293        if let Some(active_drag) = self.app.active_drag.take() {
1294            self.with_z_index(ACTIVE_DRAG_Z_INDEX, |cx| {
1295                let offset = cx.mouse_position() - active_drag.cursor_offset;
1296                let available_space = size(AvailableSpace::MinContent, AvailableSpace::MinContent);
1297                active_drag.view.draw(offset, available_space, cx);
1298            });
1299            self.active_drag = Some(active_drag);
1300        } else if let Some(active_tooltip) = self.app.active_tooltip.take() {
1301            self.with_z_index(1, |cx| {
1302                let available_space = size(AvailableSpace::MinContent, AvailableSpace::MinContent);
1303                active_tooltip
1304                    .view
1305                    .draw(active_tooltip.cursor_offset, available_space, cx);
1306            });
1307        }
1308
1309        let window_is_focused = self
1310            .window
1311            .focus
1312            .and_then(|focus_id| {
1313                self.window
1314                    .next_frame
1315                    .dispatch_tree
1316                    .focusable_node_id(focus_id)
1317            })
1318            .is_some();
1319        if window_was_focused && !window_is_focused {
1320            self.window
1321                .blur_listeners
1322                .clone()
1323                .retain(&(), |listener| listener(self));
1324        }
1325
1326        self.window
1327            .next_frame
1328            .dispatch_tree
1329            .preserve_pending_keystrokes(
1330                &mut self.window.rendered_frame.dispatch_tree,
1331                self.window.focus,
1332            );
1333        self.window.root_view = Some(root_view);
1334
1335        let window = &mut self.window;
1336        mem::swap(&mut window.rendered_frame, &mut window.next_frame);
1337
1338        let scene = self.window.rendered_frame.scene_builder.build();
1339
1340        // Set the cursor only if we're the active window.
1341        let cursor_style = self
1342            .window
1343            .requested_cursor_style
1344            .take()
1345            .unwrap_or(CursorStyle::Arrow);
1346        if self.is_window_active() {
1347            self.platform.set_cursor_style(cursor_style);
1348        }
1349
1350        self.window.drawing = false;
1351        eprintln!("window draw: {:?}", t0.elapsed());
1352
1353        scene
1354    }
1355
1356    /// Dispatch a mouse or keyboard event on the window.
1357    pub fn dispatch_event(&mut self, event: InputEvent) -> bool {
1358        // Handlers may set this to false by calling `stop_propagation`.
1359        self.app.propagate_event = true;
1360        // Handlers may set this to true by calling `prevent_default`.
1361        self.window.default_prevented = false;
1362
1363        let event = match event {
1364            // Track the mouse position with our own state, since accessing the platform
1365            // API for the mouse position can only occur on the main thread.
1366            InputEvent::MouseMove(mouse_move) => {
1367                self.window.mouse_position = mouse_move.position;
1368                self.window.modifiers = mouse_move.modifiers;
1369                InputEvent::MouseMove(mouse_move)
1370            }
1371            InputEvent::MouseDown(mouse_down) => {
1372                self.window.mouse_position = mouse_down.position;
1373                self.window.modifiers = mouse_down.modifiers;
1374                InputEvent::MouseDown(mouse_down)
1375            }
1376            InputEvent::MouseUp(mouse_up) => {
1377                self.window.mouse_position = mouse_up.position;
1378                self.window.modifiers = mouse_up.modifiers;
1379                InputEvent::MouseUp(mouse_up)
1380            }
1381            InputEvent::MouseExited(mouse_exited) => {
1382                // todo!("Should we record that the mouse is outside of the window somehow? Or are these global pixels?")
1383                self.window.modifiers = mouse_exited.modifiers;
1384
1385                InputEvent::MouseExited(mouse_exited)
1386            }
1387            InputEvent::ModifiersChanged(modifiers_changed) => {
1388                self.window.modifiers = modifiers_changed.modifiers;
1389                InputEvent::ModifiersChanged(modifiers_changed)
1390            }
1391            InputEvent::ScrollWheel(scroll_wheel) => {
1392                self.window.mouse_position = scroll_wheel.position;
1393                self.window.modifiers = scroll_wheel.modifiers;
1394                InputEvent::ScrollWheel(scroll_wheel)
1395            }
1396            // Translate dragging and dropping of external files from the operating system
1397            // to internal drag and drop events.
1398            InputEvent::FileDrop(file_drop) => match file_drop {
1399                FileDropEvent::Entered { position, files } => {
1400                    self.window.mouse_position = position;
1401                    if self.active_drag.is_none() {
1402                        self.active_drag = Some(AnyDrag {
1403                            value: Box::new(files.clone()),
1404                            view: self.build_view(|_| files).into(),
1405                            cursor_offset: position,
1406                        });
1407                    }
1408                    InputEvent::MouseMove(MouseMoveEvent {
1409                        position,
1410                        pressed_button: Some(MouseButton::Left),
1411                        modifiers: Modifiers::default(),
1412                    })
1413                }
1414                FileDropEvent::Pending { position } => {
1415                    self.window.mouse_position = position;
1416                    InputEvent::MouseMove(MouseMoveEvent {
1417                        position,
1418                        pressed_button: Some(MouseButton::Left),
1419                        modifiers: Modifiers::default(),
1420                    })
1421                }
1422                FileDropEvent::Submit { position } => {
1423                    self.activate(true);
1424                    self.window.mouse_position = position;
1425                    InputEvent::MouseUp(MouseUpEvent {
1426                        button: MouseButton::Left,
1427                        position,
1428                        modifiers: Modifiers::default(),
1429                        click_count: 1,
1430                    })
1431                }
1432                FileDropEvent::Exited => InputEvent::MouseUp(MouseUpEvent {
1433                    button: MouseButton::Left,
1434                    position: Point::default(),
1435                    modifiers: Modifiers::default(),
1436                    click_count: 1,
1437                }),
1438            },
1439            InputEvent::KeyDown(_) | InputEvent::KeyUp(_) => event,
1440        };
1441
1442        if let Some(any_mouse_event) = event.mouse_event() {
1443            self.dispatch_mouse_event(any_mouse_event);
1444        } else if let Some(any_key_event) = event.keyboard_event() {
1445            self.dispatch_key_event(any_key_event);
1446        }
1447
1448        !self.app.propagate_event
1449    }
1450
1451    fn dispatch_mouse_event(&mut self, event: &dyn Any) {
1452        if let Some(mut handlers) = self
1453            .window
1454            .rendered_frame
1455            .mouse_listeners
1456            .remove(&event.type_id())
1457        {
1458            // Because handlers may add other handlers, we sort every time.
1459            handlers.sort_by(|(a, _), (b, _)| a.cmp(b));
1460
1461            // Capture phase, events bubble from back to front. Handlers for this phase are used for
1462            // special purposes, such as detecting events outside of a given Bounds.
1463            for (_, handler) in &mut handlers {
1464                handler(event, DispatchPhase::Capture, self);
1465                if !self.app.propagate_event {
1466                    break;
1467                }
1468            }
1469
1470            // Bubble phase, where most normal handlers do their work.
1471            if self.app.propagate_event {
1472                for (_, handler) in handlers.iter_mut().rev() {
1473                    handler(event, DispatchPhase::Bubble, self);
1474                    if !self.app.propagate_event {
1475                        break;
1476                    }
1477                }
1478            }
1479
1480            if self.app.propagate_event && event.downcast_ref::<MouseUpEvent>().is_some() {
1481                self.active_drag = None;
1482            }
1483
1484            self.window
1485                .rendered_frame
1486                .mouse_listeners
1487                .insert(event.type_id(), handlers);
1488        }
1489    }
1490
1491    fn dispatch_key_event(&mut self, event: &dyn Any) {
1492        let node_id = self
1493            .window
1494            .focus
1495            .and_then(|focus_id| {
1496                self.window
1497                    .rendered_frame
1498                    .dispatch_tree
1499                    .focusable_node_id(focus_id)
1500            })
1501            .unwrap_or_else(|| self.window.rendered_frame.dispatch_tree.root_node_id());
1502
1503        let dispatch_path = self
1504            .window
1505            .rendered_frame
1506            .dispatch_tree
1507            .dispatch_path(node_id);
1508
1509        let mut actions: Vec<Box<dyn Action>> = Vec::new();
1510
1511        // Capture phase
1512        let mut context_stack: SmallVec<[KeyContext; 16]> = SmallVec::new();
1513        self.propagate_event = true;
1514
1515        for node_id in &dispatch_path {
1516            let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1517
1518            if let Some(context) = node.context.clone() {
1519                context_stack.push(context);
1520            }
1521
1522            for key_listener in node.key_listeners.clone() {
1523                key_listener(event, DispatchPhase::Capture, self);
1524                if !self.propagate_event {
1525                    return;
1526                }
1527            }
1528        }
1529
1530        // Bubble phase
1531        for node_id in dispatch_path.iter().rev() {
1532            // Handle low level key events
1533            let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1534            for key_listener in node.key_listeners.clone() {
1535                key_listener(event, DispatchPhase::Bubble, self);
1536                if !self.propagate_event {
1537                    return;
1538                }
1539            }
1540
1541            // Match keystrokes
1542            let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1543            if node.context.is_some() {
1544                if let Some(key_down_event) = event.downcast_ref::<KeyDownEvent>() {
1545                    let mut new_actions = self
1546                        .window
1547                        .rendered_frame
1548                        .dispatch_tree
1549                        .dispatch_key(&key_down_event.keystroke, &context_stack);
1550                    actions.append(&mut new_actions);
1551                }
1552
1553                context_stack.pop();
1554            }
1555        }
1556
1557        for action in actions {
1558            self.dispatch_action_on_node(node_id, action.boxed_clone());
1559            if !self.propagate_event {
1560                self.dispatch_keystroke_observers(event, Some(action));
1561                return;
1562            }
1563        }
1564        self.dispatch_keystroke_observers(event, None);
1565    }
1566
1567    pub fn has_pending_keystrokes(&self) -> bool {
1568        self.window
1569            .rendered_frame
1570            .dispatch_tree
1571            .has_pending_keystrokes()
1572    }
1573
1574    fn dispatch_action_on_node(&mut self, node_id: DispatchNodeId, action: Box<dyn Action>) {
1575        let dispatch_path = self
1576            .window
1577            .rendered_frame
1578            .dispatch_tree
1579            .dispatch_path(node_id);
1580
1581        // Capture phase
1582        for node_id in &dispatch_path {
1583            let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1584            for DispatchActionListener {
1585                action_type,
1586                listener,
1587            } in node.action_listeners.clone()
1588            {
1589                let any_action = action.as_any();
1590                if action_type == any_action.type_id() {
1591                    listener(any_action, DispatchPhase::Capture, self);
1592                    if !self.propagate_event {
1593                        return;
1594                    }
1595                }
1596            }
1597        }
1598        // Bubble phase
1599        for node_id in dispatch_path.iter().rev() {
1600            let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1601            for DispatchActionListener {
1602                action_type,
1603                listener,
1604            } in node.action_listeners.clone()
1605            {
1606                let any_action = action.as_any();
1607                if action_type == any_action.type_id() {
1608                    self.propagate_event = false; // Actions stop propagation by default during the bubble phase
1609                    listener(any_action, DispatchPhase::Bubble, self);
1610                    if !self.propagate_event {
1611                        return;
1612                    }
1613                }
1614            }
1615        }
1616    }
1617
1618    /// Register the given handler to be invoked whenever the global of the given type
1619    /// is updated.
1620    pub fn observe_global<G: 'static>(
1621        &mut self,
1622        f: impl Fn(&mut WindowContext<'_>) + 'static,
1623    ) -> Subscription {
1624        let window_handle = self.window.handle;
1625        let (subscription, activate) = self.global_observers.insert(
1626            TypeId::of::<G>(),
1627            Box::new(move |cx| window_handle.update(cx, |_, cx| f(cx)).is_ok()),
1628        );
1629        self.app.defer(move |_| activate());
1630        subscription
1631    }
1632
1633    pub fn activate_window(&self) {
1634        self.window.platform_window.activate();
1635    }
1636
1637    pub fn minimize_window(&self) {
1638        self.window.platform_window.minimize();
1639    }
1640
1641    pub fn toggle_full_screen(&self) {
1642        self.window.platform_window.toggle_full_screen();
1643    }
1644
1645    pub fn prompt(
1646        &self,
1647        level: PromptLevel,
1648        msg: &str,
1649        answers: &[&str],
1650    ) -> oneshot::Receiver<usize> {
1651        self.window.platform_window.prompt(level, msg, answers)
1652    }
1653
1654    pub fn available_actions(&self) -> Vec<Box<dyn Action>> {
1655        let node_id = self
1656            .window
1657            .focus
1658            .and_then(|focus_id| {
1659                self.window
1660                    .rendered_frame
1661                    .dispatch_tree
1662                    .focusable_node_id(focus_id)
1663            })
1664            .unwrap_or_else(|| self.window.rendered_frame.dispatch_tree.root_node_id());
1665
1666        self.window
1667            .rendered_frame
1668            .dispatch_tree
1669            .available_actions(node_id)
1670    }
1671
1672    pub fn bindings_for_action(&self, action: &dyn Action) -> Vec<KeyBinding> {
1673        self.window
1674            .rendered_frame
1675            .dispatch_tree
1676            .bindings_for_action(
1677                action,
1678                &self.window.rendered_frame.dispatch_tree.context_stack,
1679            )
1680    }
1681
1682    pub fn bindings_for_action_in(
1683        &self,
1684        action: &dyn Action,
1685        focus_handle: &FocusHandle,
1686    ) -> Vec<KeyBinding> {
1687        let dispatch_tree = &self.window.rendered_frame.dispatch_tree;
1688
1689        let Some(node_id) = dispatch_tree.focusable_node_id(focus_handle.id) else {
1690            return vec![];
1691        };
1692        let context_stack = dispatch_tree
1693            .dispatch_path(node_id)
1694            .into_iter()
1695            .filter_map(|node_id| dispatch_tree.node(node_id).context.clone())
1696            .collect();
1697        dispatch_tree.bindings_for_action(action, &context_stack)
1698    }
1699
1700    pub fn listener_for<V: Render, E>(
1701        &self,
1702        view: &View<V>,
1703        f: impl Fn(&mut V, &E, &mut ViewContext<V>) + 'static,
1704    ) -> impl Fn(&E, &mut WindowContext) + 'static {
1705        let view = view.downgrade();
1706        move |e: &E, cx: &mut WindowContext| {
1707            view.update(cx, |view, cx| f(view, e, cx)).ok();
1708        }
1709    }
1710
1711    pub fn handler_for<V: Render>(
1712        &self,
1713        view: &View<V>,
1714        f: impl Fn(&mut V, &mut ViewContext<V>) + 'static,
1715    ) -> impl Fn(&mut WindowContext) {
1716        let view = view.downgrade();
1717        move |cx: &mut WindowContext| {
1718            view.update(cx, |view, cx| f(view, cx)).ok();
1719        }
1720    }
1721
1722    //========== ELEMENT RELATED FUNCTIONS ===========
1723    pub fn with_key_dispatch<R>(
1724        &mut self,
1725        context: Option<KeyContext>,
1726        focus_handle: Option<FocusHandle>,
1727        f: impl FnOnce(Option<FocusHandle>, &mut Self) -> R,
1728    ) -> R {
1729        let window = &mut self.window;
1730        window.next_frame.dispatch_tree.push_node(context.clone());
1731        if let Some(focus_handle) = focus_handle.as_ref() {
1732            window
1733                .next_frame
1734                .dispatch_tree
1735                .make_focusable(focus_handle.id);
1736        }
1737        let result = f(focus_handle, self);
1738
1739        self.window.next_frame.dispatch_tree.pop_node();
1740
1741        result
1742    }
1743
1744    /// Register a focus listener for the next frame only. It will be cleared
1745    /// on the next frame render. You should use this method only from within elements,
1746    /// and we may want to enforce that better via a different context type.
1747    // todo!() Move this to `FrameContext` to emphasize its individuality?
1748    pub fn on_focus_changed(
1749        &mut self,
1750        listener: impl Fn(&FocusEvent, &mut WindowContext) + 'static,
1751    ) {
1752        self.window
1753            .next_frame
1754            .focus_listeners
1755            .push(Box::new(move |event, cx| {
1756                listener(event, cx);
1757            }));
1758    }
1759
1760    /// Set an input handler, such as [ElementInputHandler], which interfaces with the
1761    /// platform to receive textual input with proper integration with concerns such
1762    /// as IME interactions.
1763    pub fn handle_input(
1764        &mut self,
1765        focus_handle: &FocusHandle,
1766        input_handler: impl PlatformInputHandler,
1767    ) {
1768        if focus_handle.is_focused(self) {
1769            self.window
1770                .platform_window
1771                .set_input_handler(Box::new(input_handler));
1772        }
1773    }
1774
1775    pub fn on_window_should_close(&mut self, f: impl Fn(&mut WindowContext) -> bool + 'static) {
1776        let mut this = self.to_async();
1777        self.window
1778            .platform_window
1779            .on_should_close(Box::new(move || this.update(|_, cx| f(cx)).unwrap_or(true)))
1780    }
1781}
1782
1783impl Context for WindowContext<'_> {
1784    type Result<T> = T;
1785
1786    fn build_model<T>(
1787        &mut self,
1788        build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
1789    ) -> Model<T>
1790    where
1791        T: 'static,
1792    {
1793        let slot = self.app.entities.reserve();
1794        let model = build_model(&mut ModelContext::new(&mut *self.app, slot.downgrade()));
1795        self.entities.insert(slot, model)
1796    }
1797
1798    fn update_model<T: 'static, R>(
1799        &mut self,
1800        model: &Model<T>,
1801        update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
1802    ) -> R {
1803        let mut entity = self.entities.lease(model);
1804        let result = update(
1805            &mut *entity,
1806            &mut ModelContext::new(&mut *self.app, model.downgrade()),
1807        );
1808        self.entities.end_lease(entity);
1809        result
1810    }
1811
1812    fn update_window<T, F>(&mut self, window: AnyWindowHandle, update: F) -> Result<T>
1813    where
1814        F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
1815    {
1816        if window == self.window.handle {
1817            let root_view = self.window.root_view.clone().unwrap();
1818            Ok(update(root_view, self))
1819        } else {
1820            window.update(self.app, update)
1821        }
1822    }
1823
1824    fn read_model<T, R>(
1825        &self,
1826        handle: &Model<T>,
1827        read: impl FnOnce(&T, &AppContext) -> R,
1828    ) -> Self::Result<R>
1829    where
1830        T: 'static,
1831    {
1832        let entity = self.entities.read(handle);
1833        read(&*entity, &*self.app)
1834    }
1835
1836    fn read_window<T, R>(
1837        &self,
1838        window: &WindowHandle<T>,
1839        read: impl FnOnce(View<T>, &AppContext) -> R,
1840    ) -> Result<R>
1841    where
1842        T: 'static,
1843    {
1844        if window.any_handle == self.window.handle {
1845            let root_view = self
1846                .window
1847                .root_view
1848                .clone()
1849                .unwrap()
1850                .downcast::<T>()
1851                .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
1852            Ok(read(root_view, self))
1853        } else {
1854            self.app.read_window(window, read)
1855        }
1856    }
1857}
1858
1859impl VisualContext for WindowContext<'_> {
1860    fn build_view<V>(
1861        &mut self,
1862        build_view_state: impl FnOnce(&mut ViewContext<'_, V>) -> V,
1863    ) -> Self::Result<View<V>>
1864    where
1865        V: 'static + Render,
1866    {
1867        let slot = self.app.entities.reserve();
1868        let view = View {
1869            model: slot.clone(),
1870        };
1871        let mut cx = ViewContext::new(&mut *self.app, &mut *self.window, &view);
1872        let entity = build_view_state(&mut cx);
1873        cx.entities.insert(slot, entity);
1874
1875        cx.new_view_observers
1876            .clone()
1877            .retain(&TypeId::of::<V>(), |observer| {
1878                let any_view = AnyView::from(view.clone());
1879                (observer)(any_view, self);
1880                true
1881            });
1882
1883        view
1884    }
1885
1886    /// Update the given view. Prefer calling `View::update` instead, which calls this method.
1887    fn update_view<T: 'static, R>(
1888        &mut self,
1889        view: &View<T>,
1890        update: impl FnOnce(&mut T, &mut ViewContext<'_, T>) -> R,
1891    ) -> Self::Result<R> {
1892        let mut lease = self.app.entities.lease(&view.model);
1893        let mut cx = ViewContext::new(&mut *self.app, &mut *self.window, &view);
1894        let result = update(&mut *lease, &mut cx);
1895        cx.app.entities.end_lease(lease);
1896        result
1897    }
1898
1899    fn replace_root_view<V>(
1900        &mut self,
1901        build_view: impl FnOnce(&mut ViewContext<'_, V>) -> V,
1902    ) -> Self::Result<View<V>>
1903    where
1904        V: 'static + Render,
1905    {
1906        let slot = self.app.entities.reserve();
1907        let view = View {
1908            model: slot.clone(),
1909        };
1910        let mut cx = ViewContext::new(&mut *self.app, &mut *self.window, &view);
1911        let entity = build_view(&mut cx);
1912        self.entities.insert(slot, entity);
1913        self.window.root_view = Some(view.clone().into());
1914        view
1915    }
1916
1917    fn focus_view<V: crate::FocusableView>(&mut self, view: &View<V>) -> Self::Result<()> {
1918        self.update_view(view, |view, cx| {
1919            view.focus_handle(cx).clone().focus(cx);
1920        })
1921    }
1922
1923    fn dismiss_view<V>(&mut self, view: &View<V>) -> Self::Result<()>
1924    where
1925        V: ManagedView,
1926    {
1927        self.update_view(view, |_, cx| cx.emit(DismissEvent))
1928    }
1929}
1930
1931impl<'a> std::ops::Deref for WindowContext<'a> {
1932    type Target = AppContext;
1933
1934    fn deref(&self) -> &Self::Target {
1935        &self.app
1936    }
1937}
1938
1939impl<'a> std::ops::DerefMut for WindowContext<'a> {
1940    fn deref_mut(&mut self) -> &mut Self::Target {
1941        &mut self.app
1942    }
1943}
1944
1945impl<'a> Borrow<AppContext> for WindowContext<'a> {
1946    fn borrow(&self) -> &AppContext {
1947        &self.app
1948    }
1949}
1950
1951impl<'a> BorrowMut<AppContext> for WindowContext<'a> {
1952    fn borrow_mut(&mut self) -> &mut AppContext {
1953        &mut self.app
1954    }
1955}
1956
1957pub trait BorrowWindow: BorrowMut<Window> + BorrowMut<AppContext> {
1958    fn app_mut(&mut self) -> &mut AppContext {
1959        self.borrow_mut()
1960    }
1961
1962    fn app(&self) -> &AppContext {
1963        self.borrow()
1964    }
1965
1966    fn window(&self) -> &Window {
1967        self.borrow()
1968    }
1969
1970    fn window_mut(&mut self) -> &mut Window {
1971        self.borrow_mut()
1972    }
1973
1974    /// Pushes the given element id onto the global stack and invokes the given closure
1975    /// with a `GlobalElementId`, which disambiguates the given id in the context of its ancestor
1976    /// ids. Because elements are discarded and recreated on each frame, the `GlobalElementId` is
1977    /// used to associate state with identified elements across separate frames.
1978    fn with_element_id<R>(
1979        &mut self,
1980        id: Option<impl Into<ElementId>>,
1981        f: impl FnOnce(&mut Self) -> R,
1982    ) -> R {
1983        if let Some(id) = id.map(Into::into) {
1984            let window = self.window_mut();
1985            window.element_id_stack.push(id.into());
1986            let result = f(self);
1987            let window: &mut Window = self.borrow_mut();
1988            window.element_id_stack.pop();
1989            result
1990        } else {
1991            f(self)
1992        }
1993    }
1994
1995    /// Invoke the given function with the given content mask after intersecting it
1996    /// with the current mask.
1997    fn with_content_mask<R>(
1998        &mut self,
1999        mask: Option<ContentMask<Pixels>>,
2000        f: impl FnOnce(&mut Self) -> R,
2001    ) -> R {
2002        if let Some(mask) = mask {
2003            let mask = mask.intersect(&self.content_mask());
2004            self.window_mut().next_frame.content_mask_stack.push(mask);
2005            let result = f(self);
2006            self.window_mut().next_frame.content_mask_stack.pop();
2007            result
2008        } else {
2009            f(self)
2010        }
2011    }
2012
2013    /// Invoke the given function with the content mask reset to that
2014    /// of the window.
2015    fn break_content_mask<R>(&mut self, f: impl FnOnce(&mut Self) -> R) -> R {
2016        let mask = ContentMask {
2017            bounds: Bounds {
2018                origin: Point::default(),
2019                size: self.window().viewport_size,
2020            },
2021        };
2022        self.window_mut().next_frame.content_mask_stack.push(mask);
2023        let result = f(self);
2024        self.window_mut().next_frame.content_mask_stack.pop();
2025        result
2026    }
2027
2028    /// Update the global element offset relative to the current offset. This is used to implement
2029    /// scrolling.
2030    fn with_element_offset<R>(
2031        &mut self,
2032        offset: Point<Pixels>,
2033        f: impl FnOnce(&mut Self) -> R,
2034    ) -> R {
2035        if offset.is_zero() {
2036            return f(self);
2037        };
2038
2039        let abs_offset = self.element_offset() + offset;
2040        self.with_absolute_element_offset(abs_offset, f)
2041    }
2042
2043    /// Update the global element offset based on the given offset. This is used to implement
2044    /// drag handles and other manual painting of elements.
2045    fn with_absolute_element_offset<R>(
2046        &mut self,
2047        offset: Point<Pixels>,
2048        f: impl FnOnce(&mut Self) -> R,
2049    ) -> R {
2050        self.window_mut()
2051            .next_frame
2052            .element_offset_stack
2053            .push(offset);
2054        let result = f(self);
2055        self.window_mut().next_frame.element_offset_stack.pop();
2056        result
2057    }
2058
2059    /// Obtain the current element offset.
2060    fn element_offset(&self) -> Point<Pixels> {
2061        self.window()
2062            .next_frame
2063            .element_offset_stack
2064            .last()
2065            .copied()
2066            .unwrap_or_default()
2067    }
2068
2069    /// Update or initialize state for an element with the given id that lives across multiple
2070    /// frames. If an element with this id existed in the rendered frame, its state will be passed
2071    /// to the given closure. The state returned by the closure will be stored so it can be referenced
2072    /// when drawing the next frame.
2073    fn with_element_state<S, R>(
2074        &mut self,
2075        id: ElementId,
2076        f: impl FnOnce(Option<S>, &mut Self) -> (R, S),
2077    ) -> R
2078    where
2079        S: 'static,
2080    {
2081        self.with_element_id(Some(id), |cx| {
2082            let global_id = cx.window().element_id_stack.clone();
2083
2084            if let Some(any) = cx
2085                .window_mut()
2086                .next_frame
2087                .element_states
2088                .remove(&global_id)
2089                .or_else(|| {
2090                    cx.window_mut()
2091                        .rendered_frame
2092                        .element_states
2093                        .remove(&global_id)
2094                })
2095            {
2096                let ElementStateBox {
2097                    inner,
2098
2099                    #[cfg(debug_assertions)]
2100                    type_name
2101                } = any;
2102                // Using the extra inner option to avoid needing to reallocate a new box.
2103                let mut state_box = inner
2104                    .downcast::<Option<S>>()
2105                    .map_err(|_| {
2106                        #[cfg(debug_assertions)]
2107                        {
2108                            anyhow!(
2109                                "invalid element state type for id, requested_type {:?}, actual type: {:?}",
2110                                std::any::type_name::<S>(),
2111                                type_name
2112                            )
2113                        }
2114
2115                        #[cfg(not(debug_assertions))]
2116                        {
2117                            anyhow!(
2118                                "invalid element state type for id, requested_type {:?}",
2119                                std::any::type_name::<S>(),
2120                            )
2121                        }
2122                    })
2123                    .unwrap();
2124
2125                // Actual: Option<AnyElement> <- View
2126                // Requested: () <- AnyElemet
2127                let state = state_box
2128                    .take()
2129                    .expect("element state is already on the stack");
2130                let (result, state) = f(Some(state), cx);
2131                state_box.replace(state);
2132                cx.window_mut()
2133                    .next_frame
2134                    .element_states
2135                    .insert(global_id, ElementStateBox {
2136                        inner: state_box,
2137
2138                        #[cfg(debug_assertions)]
2139                        type_name
2140                    });
2141                result
2142            } else {
2143                let (result, state) = f(None, cx);
2144                cx.window_mut()
2145                    .next_frame
2146                    .element_states
2147                    .insert(global_id,
2148                        ElementStateBox {
2149                            inner: Box::new(Some(state)),
2150
2151                            #[cfg(debug_assertions)]
2152                            type_name: std::any::type_name::<S>()
2153                        }
2154
2155                    );
2156                result
2157            }
2158        })
2159    }
2160
2161    /// Obtain the current content mask.
2162    fn content_mask(&self) -> ContentMask<Pixels> {
2163        self.window()
2164            .next_frame
2165            .content_mask_stack
2166            .last()
2167            .cloned()
2168            .unwrap_or_else(|| ContentMask {
2169                bounds: Bounds {
2170                    origin: Point::default(),
2171                    size: self.window().viewport_size,
2172                },
2173            })
2174    }
2175
2176    /// The size of an em for the base font of the application. Adjusting this value allows the
2177    /// UI to scale, just like zooming a web page.
2178    fn rem_size(&self) -> Pixels {
2179        self.window().rem_size
2180    }
2181}
2182
2183impl Borrow<Window> for WindowContext<'_> {
2184    fn borrow(&self) -> &Window {
2185        &self.window
2186    }
2187}
2188
2189impl BorrowMut<Window> for WindowContext<'_> {
2190    fn borrow_mut(&mut self) -> &mut Window {
2191        &mut self.window
2192    }
2193}
2194
2195impl<T> BorrowWindow for T where T: BorrowMut<AppContext> + BorrowMut<Window> {}
2196
2197pub struct ViewContext<'a, V> {
2198    window_cx: WindowContext<'a>,
2199    view: &'a View<V>,
2200}
2201
2202impl<V> Borrow<AppContext> for ViewContext<'_, V> {
2203    fn borrow(&self) -> &AppContext {
2204        &*self.window_cx.app
2205    }
2206}
2207
2208impl<V> BorrowMut<AppContext> for ViewContext<'_, V> {
2209    fn borrow_mut(&mut self) -> &mut AppContext {
2210        &mut *self.window_cx.app
2211    }
2212}
2213
2214impl<V> Borrow<Window> for ViewContext<'_, V> {
2215    fn borrow(&self) -> &Window {
2216        &*self.window_cx.window
2217    }
2218}
2219
2220impl<V> BorrowMut<Window> for ViewContext<'_, V> {
2221    fn borrow_mut(&mut self) -> &mut Window {
2222        &mut *self.window_cx.window
2223    }
2224}
2225
2226impl<'a, V: 'static> ViewContext<'a, V> {
2227    pub(crate) fn new(app: &'a mut AppContext, window: &'a mut Window, view: &'a View<V>) -> Self {
2228        Self {
2229            window_cx: WindowContext::new(app, window),
2230            view,
2231        }
2232    }
2233
2234    pub fn entity_id(&self) -> EntityId {
2235        self.view.entity_id()
2236    }
2237
2238    pub fn view(&self) -> &View<V> {
2239        self.view
2240    }
2241
2242    pub fn model(&self) -> &Model<V> {
2243        &self.view.model
2244    }
2245
2246    /// Access the underlying window context.
2247    pub fn window_context(&mut self) -> &mut WindowContext<'a> {
2248        &mut self.window_cx
2249    }
2250
2251    pub fn with_z_index<R>(&mut self, z_index: u8, f: impl FnOnce(&mut Self) -> R) -> R {
2252        self.window.next_frame.z_index_stack.push(z_index);
2253        let result = f(self);
2254        self.window.next_frame.z_index_stack.pop();
2255        result
2256    }
2257
2258    pub fn on_next_frame(&mut self, f: impl FnOnce(&mut V, &mut ViewContext<V>) + 'static)
2259    where
2260        V: 'static,
2261    {
2262        let view = self.view().clone();
2263        self.window_cx.on_next_frame(move |cx| view.update(cx, f));
2264    }
2265
2266    /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
2267    /// that are currently on the stack to be returned to the app.
2268    pub fn defer(&mut self, f: impl FnOnce(&mut V, &mut ViewContext<V>) + 'static) {
2269        let view = self.view().downgrade();
2270        self.window_cx.defer(move |cx| {
2271            view.update(cx, f).ok();
2272        });
2273    }
2274
2275    pub fn observe<V2, E>(
2276        &mut self,
2277        entity: &E,
2278        mut on_notify: impl FnMut(&mut V, E, &mut ViewContext<'_, V>) + 'static,
2279    ) -> Subscription
2280    where
2281        V2: 'static,
2282        V: 'static,
2283        E: Entity<V2>,
2284    {
2285        let view = self.view().downgrade();
2286        let entity_id = entity.entity_id();
2287        let entity = entity.downgrade();
2288        let window_handle = self.window.handle;
2289        let (subscription, activate) = self.app.observers.insert(
2290            entity_id,
2291            Box::new(move |cx| {
2292                window_handle
2293                    .update(cx, |_, cx| {
2294                        if let Some(handle) = E::upgrade_from(&entity) {
2295                            view.update(cx, |this, cx| on_notify(this, handle, cx))
2296                                .is_ok()
2297                        } else {
2298                            false
2299                        }
2300                    })
2301                    .unwrap_or(false)
2302            }),
2303        );
2304        self.app.defer(move |_| activate());
2305        subscription
2306    }
2307
2308    pub fn subscribe<V2, E, Evt>(
2309        &mut self,
2310        entity: &E,
2311        mut on_event: impl FnMut(&mut V, E, &Evt, &mut ViewContext<'_, V>) + 'static,
2312    ) -> Subscription
2313    where
2314        V2: EventEmitter<Evt>,
2315        E: Entity<V2>,
2316        Evt: 'static,
2317    {
2318        let view = self.view().downgrade();
2319        let entity_id = entity.entity_id();
2320        let handle = entity.downgrade();
2321        let window_handle = self.window.handle;
2322        let (subscription, activate) = self.app.event_listeners.insert(
2323            entity_id,
2324            (
2325                TypeId::of::<Evt>(),
2326                Box::new(move |event, cx| {
2327                    window_handle
2328                        .update(cx, |_, cx| {
2329                            if let Some(handle) = E::upgrade_from(&handle) {
2330                                let event = event.downcast_ref().expect("invalid event type");
2331                                view.update(cx, |this, cx| on_event(this, handle, event, cx))
2332                                    .is_ok()
2333                            } else {
2334                                false
2335                            }
2336                        })
2337                        .unwrap_or(false)
2338                }),
2339            ),
2340        );
2341        self.app.defer(move |_| activate());
2342        subscription
2343    }
2344
2345    pub fn on_release(
2346        &mut self,
2347        on_release: impl FnOnce(&mut V, &mut WindowContext) + 'static,
2348    ) -> Subscription {
2349        let window_handle = self.window.handle;
2350        let (subscription, activate) = self.app.release_listeners.insert(
2351            self.view.model.entity_id,
2352            Box::new(move |this, cx| {
2353                let this = this.downcast_mut().expect("invalid entity type");
2354                let _ = window_handle.update(cx, |_, cx| on_release(this, cx));
2355            }),
2356        );
2357        activate();
2358        subscription
2359    }
2360
2361    pub fn observe_release<V2, E>(
2362        &mut self,
2363        entity: &E,
2364        mut on_release: impl FnMut(&mut V, &mut V2, &mut ViewContext<'_, V>) + 'static,
2365    ) -> Subscription
2366    where
2367        V: 'static,
2368        V2: 'static,
2369        E: Entity<V2>,
2370    {
2371        let view = self.view().downgrade();
2372        let entity_id = entity.entity_id();
2373        let window_handle = self.window.handle;
2374        let (subscription, activate) = self.app.release_listeners.insert(
2375            entity_id,
2376            Box::new(move |entity, cx| {
2377                let entity = entity.downcast_mut().expect("invalid entity type");
2378                let _ = window_handle.update(cx, |_, cx| {
2379                    view.update(cx, |this, cx| on_release(this, entity, cx))
2380                });
2381            }),
2382        );
2383        activate();
2384        subscription
2385    }
2386
2387    pub fn notify(&mut self) {
2388        if !self.window.drawing {
2389            self.window_cx.notify();
2390            self.window_cx.app.push_effect(Effect::Notify {
2391                emitter: self.view.model.entity_id,
2392            });
2393        }
2394    }
2395
2396    pub fn observe_window_bounds(
2397        &mut self,
2398        mut callback: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2399    ) -> Subscription {
2400        let view = self.view.downgrade();
2401        let (subscription, activate) = self.window.bounds_observers.insert(
2402            (),
2403            Box::new(move |cx| view.update(cx, |view, cx| callback(view, cx)).is_ok()),
2404        );
2405        activate();
2406        subscription
2407    }
2408
2409    pub fn observe_window_activation(
2410        &mut self,
2411        mut callback: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2412    ) -> Subscription {
2413        let view = self.view.downgrade();
2414        let (subscription, activate) = self.window.activation_observers.insert(
2415            (),
2416            Box::new(move |cx| view.update(cx, |view, cx| callback(view, cx)).is_ok()),
2417        );
2418        activate();
2419        subscription
2420    }
2421
2422    /// Register a listener to be called when the given focus handle receives focus.
2423    /// Unlike [on_focus_changed], returns a subscription and persists until the subscription
2424    /// is dropped.
2425    pub fn on_focus(
2426        &mut self,
2427        handle: &FocusHandle,
2428        mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2429    ) -> Subscription {
2430        let view = self.view.downgrade();
2431        let focus_id = handle.id;
2432        let (subscription, activate) = self.window.focus_listeners.insert(
2433            (),
2434            Box::new(move |event, cx| {
2435                view.update(cx, |view, cx| {
2436                    if event.focused.as_ref().map(|focused| focused.id) == Some(focus_id) {
2437                        listener(view, cx)
2438                    }
2439                })
2440                .is_ok()
2441            }),
2442        );
2443        self.app.defer(move |_| activate());
2444        subscription
2445    }
2446
2447    /// Register a listener to be called when the given focus handle or one of its descendants receives focus.
2448    /// Unlike [on_focus_changed], returns a subscription and persists until the subscription
2449    /// is dropped.
2450    pub fn on_focus_in(
2451        &mut self,
2452        handle: &FocusHandle,
2453        mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2454    ) -> Subscription {
2455        let view = self.view.downgrade();
2456        let focus_id = handle.id;
2457        let (subscription, activate) = self.window.focus_listeners.insert(
2458            (),
2459            Box::new(move |event, cx| {
2460                view.update(cx, |view, cx| {
2461                    if event
2462                        .focused
2463                        .as_ref()
2464                        .map_or(false, |focused| focus_id.contains(focused.id, cx))
2465                    {
2466                        listener(view, cx)
2467                    }
2468                })
2469                .is_ok()
2470            }),
2471        );
2472        self.app.defer(move |_| activate());
2473        subscription
2474    }
2475
2476    /// Register a listener to be called when the given focus handle loses focus.
2477    /// Unlike [on_focus_changed], returns a subscription and persists until the subscription
2478    /// is dropped.
2479    pub fn on_blur(
2480        &mut self,
2481        handle: &FocusHandle,
2482        mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2483    ) -> Subscription {
2484        let view = self.view.downgrade();
2485        let focus_id = handle.id;
2486        let (subscription, activate) = self.window.focus_listeners.insert(
2487            (),
2488            Box::new(move |event, cx| {
2489                view.update(cx, |view, cx| {
2490                    if event.blurred.as_ref().map(|blurred| blurred.id) == Some(focus_id) {
2491                        listener(view, cx)
2492                    }
2493                })
2494                .is_ok()
2495            }),
2496        );
2497        self.app.defer(move |_| activate());
2498        subscription
2499    }
2500
2501    /// Register a listener to be called when the window loses focus.
2502    /// Unlike [on_focus_changed], returns a subscription and persists until the subscription
2503    /// is dropped.
2504    pub fn on_blur_window(
2505        &mut self,
2506        mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2507    ) -> Subscription {
2508        let view = self.view.downgrade();
2509        let (subscription, activate) = self.window.blur_listeners.insert(
2510            (),
2511            Box::new(move |cx| view.update(cx, |view, cx| listener(view, cx)).is_ok()),
2512        );
2513        activate();
2514        subscription
2515    }
2516
2517    /// Register a listener to be called when the given focus handle or one of its descendants loses focus.
2518    /// Unlike [on_focus_changed], returns a subscription and persists until the subscription
2519    /// is dropped.
2520    pub fn on_focus_out(
2521        &mut self,
2522        handle: &FocusHandle,
2523        mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2524    ) -> Subscription {
2525        let view = self.view.downgrade();
2526        let focus_id = handle.id;
2527        let (subscription, activate) = self.window.focus_listeners.insert(
2528            (),
2529            Box::new(move |event, cx| {
2530                view.update(cx, |view, cx| {
2531                    if event
2532                        .blurred
2533                        .as_ref()
2534                        .map_or(false, |blurred| focus_id.contains(blurred.id, cx))
2535                    {
2536                        listener(view, cx)
2537                    }
2538                })
2539                .is_ok()
2540            }),
2541        );
2542        self.app.defer(move |_| activate());
2543        subscription
2544    }
2545
2546    pub fn spawn<Fut, R>(
2547        &mut self,
2548        f: impl FnOnce(WeakView<V>, AsyncWindowContext) -> Fut,
2549    ) -> Task<R>
2550    where
2551        R: 'static,
2552        Fut: Future<Output = R> + 'static,
2553    {
2554        let view = self.view().downgrade();
2555        self.window_cx.spawn(|cx| f(view, cx))
2556    }
2557
2558    pub fn update_global<G, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R
2559    where
2560        G: 'static,
2561    {
2562        let mut global = self.app.lease_global::<G>();
2563        let result = f(&mut global, self);
2564        self.app.end_global_lease(global);
2565        result
2566    }
2567
2568    pub fn observe_global<G: 'static>(
2569        &mut self,
2570        mut f: impl FnMut(&mut V, &mut ViewContext<'_, V>) + 'static,
2571    ) -> Subscription {
2572        let window_handle = self.window.handle;
2573        let view = self.view().downgrade();
2574        let (subscription, activate) = self.global_observers.insert(
2575            TypeId::of::<G>(),
2576            Box::new(move |cx| {
2577                window_handle
2578                    .update(cx, |_, cx| view.update(cx, |view, cx| f(view, cx)).is_ok())
2579                    .unwrap_or(false)
2580            }),
2581        );
2582        self.app.defer(move |_| activate());
2583        subscription
2584    }
2585
2586    pub fn on_mouse_event<Event: 'static>(
2587        &mut self,
2588        handler: impl Fn(&mut V, &Event, DispatchPhase, &mut ViewContext<V>) + 'static,
2589    ) {
2590        let handle = self.view().clone();
2591        self.window_cx.on_mouse_event(move |event, phase, cx| {
2592            handle.update(cx, |view, cx| {
2593                handler(view, event, phase, cx);
2594            })
2595        });
2596    }
2597
2598    pub fn on_key_event<Event: 'static>(
2599        &mut self,
2600        handler: impl Fn(&mut V, &Event, DispatchPhase, &mut ViewContext<V>) + 'static,
2601    ) {
2602        let handle = self.view().clone();
2603        self.window_cx.on_key_event(move |event, phase, cx| {
2604            handle.update(cx, |view, cx| {
2605                handler(view, event, phase, cx);
2606            })
2607        });
2608    }
2609
2610    pub fn on_action(
2611        &mut self,
2612        action_type: TypeId,
2613        handler: impl Fn(&mut V, &dyn Any, DispatchPhase, &mut ViewContext<V>) + 'static,
2614    ) {
2615        let handle = self.view().clone();
2616        self.window_cx
2617            .on_action(action_type, move |action, phase, cx| {
2618                handle.update(cx, |view, cx| {
2619                    handler(view, action, phase, cx);
2620                })
2621            });
2622    }
2623
2624    pub fn emit<Evt>(&mut self, event: Evt)
2625    where
2626        Evt: 'static,
2627        V: EventEmitter<Evt>,
2628    {
2629        let emitter = self.view.model.entity_id;
2630        self.app.push_effect(Effect::Emit {
2631            emitter,
2632            event_type: TypeId::of::<Evt>(),
2633            event: Box::new(event),
2634        });
2635    }
2636
2637    pub fn focus_self(&mut self)
2638    where
2639        V: FocusableView,
2640    {
2641        self.defer(|view, cx| view.focus_handle(cx).focus(cx))
2642    }
2643
2644    pub fn dismiss_self(&mut self)
2645    where
2646        V: ManagedView,
2647    {
2648        self.defer(|_, cx| cx.emit(DismissEvent))
2649    }
2650
2651    pub fn listener<E>(
2652        &self,
2653        f: impl Fn(&mut V, &E, &mut ViewContext<V>) + 'static,
2654    ) -> impl Fn(&E, &mut WindowContext) + 'static {
2655        let view = self.view().downgrade();
2656        move |e: &E, cx: &mut WindowContext| {
2657            view.update(cx, |view, cx| f(view, e, cx)).ok();
2658        }
2659    }
2660}
2661
2662impl<V> Context for ViewContext<'_, V> {
2663    type Result<U> = U;
2664
2665    fn build_model<T: 'static>(
2666        &mut self,
2667        build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
2668    ) -> Model<T> {
2669        self.window_cx.build_model(build_model)
2670    }
2671
2672    fn update_model<T: 'static, R>(
2673        &mut self,
2674        model: &Model<T>,
2675        update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
2676    ) -> R {
2677        self.window_cx.update_model(model, update)
2678    }
2679
2680    fn update_window<T, F>(&mut self, window: AnyWindowHandle, update: F) -> Result<T>
2681    where
2682        F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
2683    {
2684        self.window_cx.update_window(window, update)
2685    }
2686
2687    fn read_model<T, R>(
2688        &self,
2689        handle: &Model<T>,
2690        read: impl FnOnce(&T, &AppContext) -> R,
2691    ) -> Self::Result<R>
2692    where
2693        T: 'static,
2694    {
2695        self.window_cx.read_model(handle, read)
2696    }
2697
2698    fn read_window<T, R>(
2699        &self,
2700        window: &WindowHandle<T>,
2701        read: impl FnOnce(View<T>, &AppContext) -> R,
2702    ) -> Result<R>
2703    where
2704        T: 'static,
2705    {
2706        self.window_cx.read_window(window, read)
2707    }
2708}
2709
2710impl<V: 'static> VisualContext for ViewContext<'_, V> {
2711    fn build_view<W: Render + 'static>(
2712        &mut self,
2713        build_view_state: impl FnOnce(&mut ViewContext<'_, W>) -> W,
2714    ) -> Self::Result<View<W>> {
2715        self.window_cx.build_view(build_view_state)
2716    }
2717
2718    fn update_view<V2: 'static, R>(
2719        &mut self,
2720        view: &View<V2>,
2721        update: impl FnOnce(&mut V2, &mut ViewContext<'_, V2>) -> R,
2722    ) -> Self::Result<R> {
2723        self.window_cx.update_view(view, update)
2724    }
2725
2726    fn replace_root_view<W>(
2727        &mut self,
2728        build_view: impl FnOnce(&mut ViewContext<'_, W>) -> W,
2729    ) -> Self::Result<View<W>>
2730    where
2731        W: 'static + Render,
2732    {
2733        self.window_cx.replace_root_view(build_view)
2734    }
2735
2736    fn focus_view<W: FocusableView>(&mut self, view: &View<W>) -> Self::Result<()> {
2737        self.window_cx.focus_view(view)
2738    }
2739
2740    fn dismiss_view<W: ManagedView>(&mut self, view: &View<W>) -> Self::Result<()> {
2741        self.window_cx.dismiss_view(view)
2742    }
2743}
2744
2745impl<'a, V> std::ops::Deref for ViewContext<'a, V> {
2746    type Target = WindowContext<'a>;
2747
2748    fn deref(&self) -> &Self::Target {
2749        &self.window_cx
2750    }
2751}
2752
2753impl<'a, V> std::ops::DerefMut for ViewContext<'a, V> {
2754    fn deref_mut(&mut self) -> &mut Self::Target {
2755        &mut self.window_cx
2756    }
2757}
2758
2759// #[derive(Clone, Copy, Eq, PartialEq, Hash)]
2760slotmap::new_key_type! { pub struct WindowId; }
2761
2762impl WindowId {
2763    pub fn as_u64(&self) -> u64 {
2764        self.0.as_ffi()
2765    }
2766}
2767
2768#[derive(Deref, DerefMut)]
2769pub struct WindowHandle<V> {
2770    #[deref]
2771    #[deref_mut]
2772    pub(crate) any_handle: AnyWindowHandle,
2773    state_type: PhantomData<V>,
2774}
2775
2776impl<V: 'static + Render> WindowHandle<V> {
2777    pub fn new(id: WindowId) -> Self {
2778        WindowHandle {
2779            any_handle: AnyWindowHandle {
2780                id,
2781                state_type: TypeId::of::<V>(),
2782            },
2783            state_type: PhantomData,
2784        }
2785    }
2786
2787    pub fn root<C>(&self, cx: &mut C) -> Result<View<V>>
2788    where
2789        C: Context,
2790    {
2791        Flatten::flatten(cx.update_window(self.any_handle, |root_view, _| {
2792            root_view
2793                .downcast::<V>()
2794                .map_err(|_| anyhow!("the type of the window's root view has changed"))
2795        }))
2796    }
2797
2798    pub fn update<C, R>(
2799        &self,
2800        cx: &mut C,
2801        update: impl FnOnce(&mut V, &mut ViewContext<'_, V>) -> R,
2802    ) -> Result<R>
2803    where
2804        C: Context,
2805    {
2806        cx.update_window(self.any_handle, |root_view, cx| {
2807            let view = root_view
2808                .downcast::<V>()
2809                .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
2810            Ok(cx.update_view(&view, update))
2811        })?
2812    }
2813
2814    pub fn read<'a>(&self, cx: &'a AppContext) -> Result<&'a V> {
2815        let x = cx
2816            .windows
2817            .get(self.id)
2818            .and_then(|window| {
2819                window
2820                    .as_ref()
2821                    .and_then(|window| window.root_view.clone())
2822                    .map(|root_view| root_view.downcast::<V>())
2823            })
2824            .ok_or_else(|| anyhow!("window not found"))?
2825            .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
2826
2827        Ok(x.read(cx))
2828    }
2829
2830    pub fn read_with<C, R>(&self, cx: &C, read_with: impl FnOnce(&V, &AppContext) -> R) -> Result<R>
2831    where
2832        C: Context,
2833    {
2834        cx.read_window(self, |root_view, cx| read_with(root_view.read(cx), cx))
2835    }
2836
2837    pub fn root_view<C>(&self, cx: &C) -> Result<View<V>>
2838    where
2839        C: Context,
2840    {
2841        cx.read_window(self, |root_view, _cx| root_view.clone())
2842    }
2843
2844    pub fn is_active(&self, cx: &AppContext) -> Option<bool> {
2845        cx.windows
2846            .get(self.id)
2847            .and_then(|window| window.as_ref().map(|window| window.active))
2848    }
2849}
2850
2851impl<V> Copy for WindowHandle<V> {}
2852
2853impl<V> Clone for WindowHandle<V> {
2854    fn clone(&self) -> Self {
2855        WindowHandle {
2856            any_handle: self.any_handle,
2857            state_type: PhantomData,
2858        }
2859    }
2860}
2861
2862impl<V> PartialEq for WindowHandle<V> {
2863    fn eq(&self, other: &Self) -> bool {
2864        self.any_handle == other.any_handle
2865    }
2866}
2867
2868impl<V> Eq for WindowHandle<V> {}
2869
2870impl<V> Hash for WindowHandle<V> {
2871    fn hash<H: Hasher>(&self, state: &mut H) {
2872        self.any_handle.hash(state);
2873    }
2874}
2875
2876impl<V: 'static> Into<AnyWindowHandle> for WindowHandle<V> {
2877    fn into(self) -> AnyWindowHandle {
2878        self.any_handle
2879    }
2880}
2881
2882#[derive(Copy, Clone, PartialEq, Eq, Hash)]
2883pub struct AnyWindowHandle {
2884    pub(crate) id: WindowId,
2885    state_type: TypeId,
2886}
2887
2888impl AnyWindowHandle {
2889    pub fn window_id(&self) -> WindowId {
2890        self.id
2891    }
2892
2893    pub fn downcast<T: 'static>(&self) -> Option<WindowHandle<T>> {
2894        if TypeId::of::<T>() == self.state_type {
2895            Some(WindowHandle {
2896                any_handle: *self,
2897                state_type: PhantomData,
2898            })
2899        } else {
2900            None
2901        }
2902    }
2903
2904    pub fn update<C, R>(
2905        self,
2906        cx: &mut C,
2907        update: impl FnOnce(AnyView, &mut WindowContext<'_>) -> R,
2908    ) -> Result<R>
2909    where
2910        C: Context,
2911    {
2912        cx.update_window(self, update)
2913    }
2914
2915    pub fn read<T, C, R>(self, cx: &C, read: impl FnOnce(View<T>, &AppContext) -> R) -> Result<R>
2916    where
2917        C: Context,
2918        T: 'static,
2919    {
2920        let view = self
2921            .downcast::<T>()
2922            .context("the type of the window's root view has changed")?;
2923
2924        cx.read_window(&view, read)
2925    }
2926}
2927
2928// #[cfg(any(test, feature = "test-support"))]
2929// impl From<SmallVec<[u32; 16]>> for StackingOrder {
2930//     fn from(small_vec: SmallVec<[u32; 16]>) -> Self {
2931//         StackingOrder(small_vec)
2932//     }
2933// }
2934
2935#[derive(Clone, Debug, Eq, PartialEq, Hash)]
2936pub enum ElementId {
2937    View(EntityId),
2938    Integer(usize),
2939    Name(SharedString),
2940    FocusHandle(FocusId),
2941    NamedInteger(SharedString, usize),
2942}
2943
2944impl ElementId {
2945    pub(crate) fn from_entity_id(entity_id: EntityId) -> Self {
2946        ElementId::View(entity_id)
2947    }
2948}
2949
2950impl TryInto<SharedString> for ElementId {
2951    type Error = anyhow::Error;
2952
2953    fn try_into(self) -> anyhow::Result<SharedString> {
2954        if let ElementId::Name(name) = self {
2955            Ok(name)
2956        } else {
2957            Err(anyhow!("element id is not string"))
2958        }
2959    }
2960}
2961
2962impl From<usize> for ElementId {
2963    fn from(id: usize) -> Self {
2964        ElementId::Integer(id)
2965    }
2966}
2967
2968impl From<i32> for ElementId {
2969    fn from(id: i32) -> Self {
2970        Self::Integer(id as usize)
2971    }
2972}
2973
2974impl From<SharedString> for ElementId {
2975    fn from(name: SharedString) -> Self {
2976        ElementId::Name(name)
2977    }
2978}
2979
2980impl From<&'static str> for ElementId {
2981    fn from(name: &'static str) -> Self {
2982        ElementId::Name(name.into())
2983    }
2984}
2985
2986impl<'a> From<&'a FocusHandle> for ElementId {
2987    fn from(handle: &'a FocusHandle) -> Self {
2988        ElementId::FocusHandle(handle.id)
2989    }
2990}
2991
2992impl From<(&'static str, EntityId)> for ElementId {
2993    fn from((name, id): (&'static str, EntityId)) -> Self {
2994        ElementId::NamedInteger(name.into(), id.as_u64() as usize)
2995    }
2996}
2997
2998impl From<(&'static str, usize)> for ElementId {
2999    fn from((name, id): (&'static str, usize)) -> Self {
3000        ElementId::NamedInteger(name.into(), id)
3001    }
3002}
3003
3004impl From<(&'static str, u64)> for ElementId {
3005    fn from((name, id): (&'static str, u64)) -> Self {
3006        ElementId::NamedInteger(name.into(), id as usize)
3007    }
3008}
3009
3010/// A rectangle, to be rendered on the screen by GPUI at the given position and size.
3011pub struct PaintQuad {
3012    bounds: Bounds<Pixels>,
3013    corner_radii: Corners<Pixels>,
3014    background: Hsla,
3015    border_widths: Edges<Pixels>,
3016    border_color: Hsla,
3017}
3018
3019impl PaintQuad {
3020    /// Set the corner radii of the quad.
3021    pub fn corner_radii(self, corner_radii: impl Into<Corners<Pixels>>) -> Self {
3022        PaintQuad {
3023            corner_radii: corner_radii.into(),
3024            ..self
3025        }
3026    }
3027
3028    /// Set the border widths of the quad.
3029    pub fn border_widths(self, border_widths: impl Into<Edges<Pixels>>) -> Self {
3030        PaintQuad {
3031            border_widths: border_widths.into(),
3032            ..self
3033        }
3034    }
3035
3036    /// Set the border color of the quad.
3037    pub fn border_color(self, border_color: impl Into<Hsla>) -> Self {
3038        PaintQuad {
3039            border_color: border_color.into(),
3040            ..self
3041        }
3042    }
3043
3044    /// Set the background color of the quad.
3045    pub fn background(self, background: impl Into<Hsla>) -> Self {
3046        PaintQuad {
3047            background: background.into(),
3048            ..self
3049        }
3050    }
3051}
3052
3053/// Create a quad with the given parameters.
3054pub fn quad(
3055    bounds: Bounds<Pixels>,
3056    corner_radii: impl Into<Corners<Pixels>>,
3057    background: impl Into<Hsla>,
3058    border_widths: impl Into<Edges<Pixels>>,
3059    border_color: impl Into<Hsla>,
3060) -> PaintQuad {
3061    PaintQuad {
3062        bounds,
3063        corner_radii: corner_radii.into(),
3064        background: background.into(),
3065        border_widths: border_widths.into(),
3066        border_color: border_color.into(),
3067    }
3068}
3069
3070/// Create a filled quad with the given bounds and background color.
3071pub fn fill(bounds: impl Into<Bounds<Pixels>>, background: impl Into<Hsla>) -> PaintQuad {
3072    PaintQuad {
3073        bounds: bounds.into(),
3074        corner_radii: (0.).into(),
3075        background: background.into(),
3076        border_widths: (0.).into(),
3077        border_color: transparent_black(),
3078    }
3079}
3080
3081/// Create a rectangle outline with the given bounds, border color, and a 1px border width
3082pub fn outline(bounds: impl Into<Bounds<Pixels>>, border_color: impl Into<Hsla>) -> PaintQuad {
3083    PaintQuad {
3084        bounds: bounds.into(),
3085        corner_radii: (0.).into(),
3086        background: transparent_black(),
3087        border_widths: (1.).into(),
3088        border_color: border_color.into(),
3089    }
3090}