window.rs

   1#![deny(missing_docs)]
   2
   3use crate::{
   4    px, size, transparent_black, Action, AnyDrag, AnyTooltip, AnyView, AppContext, Arena,
   5    AsyncWindowContext, AvailableSpace, Bounds, BoxShadow, Context, Corners, CursorStyle,
   6    DevicePixels, DispatchActionListener, DispatchNodeId, DispatchTree, DisplayId, Edges, Effect,
   7    Entity, EntityId, EventEmitter, FileDropEvent, Flatten, FontId, GlobalElementId, GlyphId, Hsla,
   8    ImageData, InputEvent, IsZero, KeyBinding, KeyContext, KeyDownEvent, KeystrokeEvent, LayoutId,
   9    Model, ModelContext, Modifiers, MonochromeSprite, MouseButton, MouseMoveEvent, MouseUpEvent,
  10    Path, Pixels, PlatformAtlas, PlatformDisplay, PlatformInputHandler, PlatformWindow, Point,
  11    PolychromeSprite, PromptLevel, Quad, Render, RenderGlyphParams, RenderImageParams,
  12    RenderSvgParams, ScaledPixels, Scene, Shadow, SharedString, Size, Style, SubscriberSet,
  13    Subscription, Surface, TaffyLayoutEngine, Task, Underline, UnderlineStyle, View, VisualContext,
  14    WeakView, WindowBounds, WindowOptions, SUBPIXEL_VARIANTS,
  15};
  16use anyhow::{anyhow, Context as _, Result};
  17use collections::{FxHashMap, FxHashSet};
  18use derive_more::{Deref, DerefMut};
  19use futures::{
  20    channel::{mpsc, oneshot},
  21    StreamExt,
  22};
  23use media::core_video::CVImageBuffer;
  24use parking_lot::RwLock;
  25use slotmap::SlotMap;
  26use smallvec::SmallVec;
  27use std::{
  28    any::{Any, TypeId},
  29    borrow::{Borrow, BorrowMut, Cow},
  30    cell::RefCell,
  31    collections::hash_map::Entry,
  32    fmt::Debug,
  33    future::Future,
  34    hash::{Hash, Hasher},
  35    marker::PhantomData,
  36    mem,
  37    rc::Rc,
  38    sync::{
  39        atomic::{AtomicUsize, Ordering::SeqCst},
  40        Arc,
  41    },
  42};
  43use util::{post_inc, ResultExt};
  44
  45const ACTIVE_DRAG_Z_INDEX: u8 = 1;
  46
  47/// A global stacking order, which is created by stacking successive z-index values.
  48/// Each z-index will always be interpreted in the context of its parent z-index.
  49#[derive(Deref, DerefMut, Clone, Ord, PartialOrd, PartialEq, Eq, Default)]
  50pub struct StackingOrder {
  51    #[deref]
  52    #[deref_mut]
  53    context_stack: SmallVec<[u8; 64]>,
  54    id: u32,
  55}
  56
  57impl std::fmt::Debug for StackingOrder {
  58    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
  59        let mut stacks = self.context_stack.iter().peekable();
  60        write!(f, "[({}): ", self.id)?;
  61        while let Some(z_index) = stacks.next() {
  62            write!(f, "{z_index}")?;
  63            if stacks.peek().is_some() {
  64                write!(f, "->")?;
  65            }
  66        }
  67        write!(f, "]")?;
  68        Ok(())
  69    }
  70}
  71
  72/// Represents the two different phases when dispatching events.
  73#[derive(Default, Copy, Clone, Debug, Eq, PartialEq)]
  74pub enum DispatchPhase {
  75    /// After the capture phase comes the bubble phase, in which mouse event listeners are
  76    /// invoked front to back and keyboard event listeners are invoked from the focused element
  77    /// to the root of the element tree. This is the phase you'll most commonly want to use when
  78    /// registering event listeners.
  79    #[default]
  80    Bubble,
  81    /// During the initial capture phase, mouse event listeners are invoked back to front, and keyboard
  82    /// listeners are invoked from the root of the tree downward toward the focused element. This phase
  83    /// is used for special purposes such as clearing the "pressed" state for click events. If
  84    /// you stop event propagation during this phase, you need to know what you're doing. Handlers
  85    /// outside of the immediate region may rely on detecting non-local events during this phase.
  86    Capture,
  87}
  88
  89impl DispatchPhase {
  90    /// Returns true if this represents the "bubble" phase.
  91    pub fn bubble(self) -> bool {
  92        self == DispatchPhase::Bubble
  93    }
  94
  95    /// Returns true if this represents the "capture" phase.
  96    pub fn capture(self) -> bool {
  97        self == DispatchPhase::Capture
  98    }
  99}
 100
 101type AnyObserver = Box<dyn FnMut(&mut WindowContext) -> bool + 'static>;
 102type AnyMouseListener = Box<dyn FnMut(&dyn Any, DispatchPhase, &mut WindowContext) + 'static>;
 103type AnyWindowFocusListener = Box<dyn FnMut(&FocusEvent, &mut WindowContext) -> bool + 'static>;
 104
 105struct FocusEvent {
 106    previous_focus_path: SmallVec<[FocusId; 8]>,
 107    current_focus_path: SmallVec<[FocusId; 8]>,
 108}
 109
 110slotmap::new_key_type! {
 111    /// A globally unique identifier for a focusable element.
 112    pub struct FocusId;
 113}
 114
 115thread_local! {
 116    pub(crate) static ELEMENT_ARENA: RefCell<Arena> = RefCell::new(Arena::new(4 * 1024 * 1024));
 117}
 118
 119impl FocusId {
 120    /// Obtains whether the element associated with this handle is currently focused.
 121    pub fn is_focused(&self, cx: &WindowContext) -> bool {
 122        cx.window.focus == Some(*self)
 123    }
 124
 125    /// Obtains whether the element associated with this handle contains the focused
 126    /// element or is itself focused.
 127    pub fn contains_focused(&self, cx: &WindowContext) -> bool {
 128        cx.focused()
 129            .map_or(false, |focused| self.contains(focused.id, cx))
 130    }
 131
 132    /// Obtains whether the element associated with this handle is contained within the
 133    /// focused element or is itself focused.
 134    pub fn within_focused(&self, cx: &WindowContext) -> bool {
 135        let focused = cx.focused();
 136        focused.map_or(false, |focused| focused.id.contains(*self, cx))
 137    }
 138
 139    /// Obtains whether this handle contains the given handle in the most recently rendered frame.
 140    pub(crate) fn contains(&self, other: Self, cx: &WindowContext) -> bool {
 141        cx.window
 142            .rendered_frame
 143            .dispatch_tree
 144            .focus_contains(*self, other)
 145    }
 146}
 147
 148/// A handle which can be used to track and manipulate the focused element in a window.
 149pub struct FocusHandle {
 150    pub(crate) id: FocusId,
 151    handles: Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>,
 152}
 153
 154impl std::fmt::Debug for FocusHandle {
 155    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 156        f.write_fmt(format_args!("FocusHandle({:?})", self.id))
 157    }
 158}
 159
 160impl FocusHandle {
 161    pub(crate) fn new(handles: &Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>) -> Self {
 162        let id = handles.write().insert(AtomicUsize::new(1));
 163        Self {
 164            id,
 165            handles: handles.clone(),
 166        }
 167    }
 168
 169    pub(crate) fn for_id(
 170        id: FocusId,
 171        handles: &Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>,
 172    ) -> Option<Self> {
 173        let lock = handles.read();
 174        let ref_count = lock.get(id)?;
 175        if ref_count.load(SeqCst) == 0 {
 176            None
 177        } else {
 178            ref_count.fetch_add(1, SeqCst);
 179            Some(Self {
 180                id,
 181                handles: handles.clone(),
 182            })
 183        }
 184    }
 185
 186    /// Moves the focus to the element associated with this handle.
 187    pub fn focus(&self, cx: &mut WindowContext) {
 188        cx.focus(self)
 189    }
 190
 191    /// Obtains whether the element associated with this handle is currently focused.
 192    pub fn is_focused(&self, cx: &WindowContext) -> bool {
 193        self.id.is_focused(cx)
 194    }
 195
 196    /// Obtains whether the element associated with this handle contains the focused
 197    /// element or is itself focused.
 198    pub fn contains_focused(&self, cx: &WindowContext) -> bool {
 199        self.id.contains_focused(cx)
 200    }
 201
 202    /// Obtains whether the element associated with this handle is contained within the
 203    /// focused element or is itself focused.
 204    pub fn within_focused(&self, cx: &WindowContext) -> bool {
 205        self.id.within_focused(cx)
 206    }
 207
 208    /// Obtains whether this handle contains the given handle in the most recently rendered frame.
 209    pub fn contains(&self, other: &Self, cx: &WindowContext) -> bool {
 210        self.id.contains(other.id, cx)
 211    }
 212}
 213
 214impl Clone for FocusHandle {
 215    fn clone(&self) -> Self {
 216        Self::for_id(self.id, &self.handles).unwrap()
 217    }
 218}
 219
 220impl PartialEq for FocusHandle {
 221    fn eq(&self, other: &Self) -> bool {
 222        self.id == other.id
 223    }
 224}
 225
 226impl Eq for FocusHandle {}
 227
 228impl Drop for FocusHandle {
 229    fn drop(&mut self) {
 230        self.handles
 231            .read()
 232            .get(self.id)
 233            .unwrap()
 234            .fetch_sub(1, SeqCst);
 235    }
 236}
 237
 238/// FocusableView allows users of your view to easily
 239/// focus it (using cx.focus_view(view))
 240pub trait FocusableView: 'static + Render {
 241    /// Returns the focus handle associated with this view.
 242    fn focus_handle(&self, cx: &AppContext) -> FocusHandle;
 243}
 244
 245/// ManagedView is a view (like a Modal, Popover, Menu, etc.)
 246/// where the lifecycle of the view is handled by another view.
 247pub trait ManagedView: FocusableView + EventEmitter<DismissEvent> {}
 248
 249impl<M: FocusableView + EventEmitter<DismissEvent>> ManagedView for M {}
 250
 251/// Emitted by implementers of [`ManagedView`] to indicate the view should be dismissed, such as when a view is presented as a modal.
 252pub struct DismissEvent;
 253
 254// Holds the state for a specific window.
 255#[doc(hidden)]
 256pub struct Window {
 257    pub(crate) handle: AnyWindowHandle,
 258    pub(crate) removed: bool,
 259    pub(crate) platform_window: Box<dyn PlatformWindow>,
 260    display_id: DisplayId,
 261    sprite_atlas: Arc<dyn PlatformAtlas>,
 262    rem_size: Pixels,
 263    viewport_size: Size<Pixels>,
 264    layout_engine: Option<TaffyLayoutEngine>,
 265    pub(crate) root_view: Option<AnyView>,
 266    pub(crate) element_id_stack: GlobalElementId,
 267    pub(crate) rendered_frame: Frame,
 268    pub(crate) next_frame: Frame,
 269    pub(crate) dirty_views: FxHashSet<EntityId>,
 270    pub(crate) focus_handles: Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>,
 271    focus_listeners: SubscriberSet<(), AnyWindowFocusListener>,
 272    focus_lost_listeners: SubscriberSet<(), AnyObserver>,
 273    default_prevented: bool,
 274    mouse_position: Point<Pixels>,
 275    modifiers: Modifiers,
 276    scale_factor: f32,
 277    bounds: WindowBounds,
 278    bounds_observers: SubscriberSet<(), AnyObserver>,
 279    active: bool,
 280    pub(crate) dirty: bool,
 281    pub(crate) refreshing: bool,
 282    pub(crate) drawing: bool,
 283    activation_observers: SubscriberSet<(), AnyObserver>,
 284    pub(crate) focus: Option<FocusId>,
 285    focus_enabled: bool,
 286
 287    #[cfg(any(test, feature = "test-support"))]
 288    pub(crate) focus_invalidated: bool,
 289}
 290
 291pub(crate) struct ElementStateBox {
 292    inner: Box<dyn Any>,
 293    parent_view_id: EntityId,
 294    #[cfg(debug_assertions)]
 295    type_name: &'static str,
 296}
 297
 298struct RequestedInputHandler {
 299    view_id: EntityId,
 300    handler: Option<Box<dyn PlatformInputHandler>>,
 301}
 302
 303struct TooltipRequest {
 304    view_id: EntityId,
 305    tooltip: AnyTooltip,
 306}
 307
 308pub(crate) struct Frame {
 309    focus: Option<FocusId>,
 310    window_active: bool,
 311    pub(crate) element_states: FxHashMap<GlobalElementId, ElementStateBox>,
 312    mouse_listeners: FxHashMap<TypeId, Vec<(StackingOrder, EntityId, AnyMouseListener)>>,
 313    pub(crate) dispatch_tree: DispatchTree,
 314    pub(crate) scene: Scene,
 315    pub(crate) depth_map: Vec<(StackingOrder, EntityId, Bounds<Pixels>)>,
 316    pub(crate) z_index_stack: StackingOrder,
 317    pub(crate) next_stacking_order_id: u32,
 318    content_mask_stack: Vec<ContentMask<Pixels>>,
 319    element_offset_stack: Vec<Point<Pixels>>,
 320    requested_input_handler: Option<RequestedInputHandler>,
 321    tooltip_request: Option<TooltipRequest>,
 322    cursor_styles: FxHashMap<EntityId, CursorStyle>,
 323    requested_cursor_style: Option<CursorStyle>,
 324    pub(crate) view_stack: Vec<EntityId>,
 325    pub(crate) reused_views: FxHashSet<EntityId>,
 326}
 327
 328impl Frame {
 329    fn new(dispatch_tree: DispatchTree) -> Self {
 330        Frame {
 331            focus: None,
 332            window_active: false,
 333            element_states: FxHashMap::default(),
 334            mouse_listeners: FxHashMap::default(),
 335            dispatch_tree,
 336            scene: Scene::default(),
 337            depth_map: Vec::new(),
 338            z_index_stack: StackingOrder::default(),
 339            next_stacking_order_id: 0,
 340            content_mask_stack: Vec::new(),
 341            element_offset_stack: Vec::new(),
 342            requested_input_handler: None,
 343            tooltip_request: None,
 344            cursor_styles: FxHashMap::default(),
 345            requested_cursor_style: None,
 346            view_stack: Vec::new(),
 347            reused_views: FxHashSet::default(),
 348        }
 349    }
 350
 351    fn clear(&mut self) {
 352        self.element_states.clear();
 353        self.mouse_listeners.values_mut().for_each(Vec::clear);
 354        self.dispatch_tree.clear();
 355        self.depth_map.clear();
 356        self.next_stacking_order_id = 0;
 357        self.reused_views.clear();
 358        self.scene.clear();
 359        self.requested_input_handler.take();
 360        self.tooltip_request.take();
 361        self.cursor_styles.clear();
 362        self.requested_cursor_style.take();
 363        debug_assert_eq!(self.view_stack.len(), 0);
 364    }
 365
 366    fn focus_path(&self) -> SmallVec<[FocusId; 8]> {
 367        self.focus
 368            .map(|focus_id| self.dispatch_tree.focus_path(focus_id))
 369            .unwrap_or_default()
 370    }
 371
 372    fn finish(&mut self, prev_frame: &mut Self) {
 373        // Reuse mouse listeners that didn't change since the last frame.
 374        for (type_id, listeners) in &mut prev_frame.mouse_listeners {
 375            let next_listeners = self.mouse_listeners.entry(*type_id).or_default();
 376            for (order, view_id, listener) in listeners.drain(..) {
 377                if self.reused_views.contains(&view_id) {
 378                    next_listeners.push((order, view_id, listener));
 379                }
 380            }
 381        }
 382
 383        // Reuse entries in the depth map that didn't change since the last frame.
 384        for (order, view_id, bounds) in prev_frame.depth_map.drain(..) {
 385            if self.reused_views.contains(&view_id) {
 386                match self
 387                    .depth_map
 388                    .binary_search_by(|(level, _, _)| order.cmp(level))
 389                {
 390                    Ok(i) | Err(i) => self.depth_map.insert(i, (order, view_id, bounds)),
 391                }
 392            }
 393        }
 394
 395        // Retain element states for views that didn't change since the last frame.
 396        for (element_id, state) in prev_frame.element_states.drain() {
 397            if self.reused_views.contains(&state.parent_view_id) {
 398                self.element_states.entry(element_id).or_insert(state);
 399            }
 400        }
 401
 402        // Reuse geometry that didn't change since the last frame.
 403        self.scene
 404            .reuse_views(&self.reused_views, &mut prev_frame.scene);
 405        self.scene.finish();
 406    }
 407}
 408
 409impl Window {
 410    pub(crate) fn new(
 411        handle: AnyWindowHandle,
 412        options: WindowOptions,
 413        cx: &mut AppContext,
 414    ) -> Self {
 415        let platform_window = cx.platform.open_window(handle, options);
 416        let display_id = platform_window.display().id();
 417        let sprite_atlas = platform_window.sprite_atlas();
 418        let mouse_position = platform_window.mouse_position();
 419        let modifiers = platform_window.modifiers();
 420        let content_size = platform_window.content_size();
 421        let scale_factor = platform_window.scale_factor();
 422        let bounds = platform_window.bounds();
 423
 424        platform_window.on_request_frame(Box::new({
 425            let mut cx = cx.to_async();
 426            move || {
 427                handle.update(&mut cx, |_, cx| cx.draw()).log_err();
 428            }
 429        }));
 430        platform_window.on_resize(Box::new({
 431            let mut cx = cx.to_async();
 432            move |_, _| {
 433                handle
 434                    .update(&mut cx, |_, cx| cx.window_bounds_changed())
 435                    .log_err();
 436            }
 437        }));
 438        platform_window.on_moved(Box::new({
 439            let mut cx = cx.to_async();
 440            move || {
 441                handle
 442                    .update(&mut cx, |_, cx| cx.window_bounds_changed())
 443                    .log_err();
 444            }
 445        }));
 446        platform_window.on_active_status_change(Box::new({
 447            let mut cx = cx.to_async();
 448            move |active| {
 449                handle
 450                    .update(&mut cx, |_, cx| {
 451                        cx.window.active = active;
 452                        cx.window
 453                            .activation_observers
 454                            .clone()
 455                            .retain(&(), |callback| callback(cx));
 456                    })
 457                    .log_err();
 458            }
 459        }));
 460
 461        platform_window.on_input({
 462            let mut cx = cx.to_async();
 463            Box::new(move |event| {
 464                handle
 465                    .update(&mut cx, |_, cx| cx.dispatch_event(event))
 466                    .log_err()
 467                    .unwrap_or(false)
 468            })
 469        });
 470
 471        Window {
 472            handle,
 473            removed: false,
 474            platform_window,
 475            display_id,
 476            sprite_atlas,
 477            rem_size: px(16.),
 478            viewport_size: content_size,
 479            layout_engine: Some(TaffyLayoutEngine::new()),
 480            root_view: None,
 481            element_id_stack: GlobalElementId::default(),
 482            rendered_frame: Frame::new(DispatchTree::new(cx.keymap.clone(), cx.actions.clone())),
 483            next_frame: Frame::new(DispatchTree::new(cx.keymap.clone(), cx.actions.clone())),
 484            dirty_views: FxHashSet::default(),
 485            focus_handles: Arc::new(RwLock::new(SlotMap::with_key())),
 486            focus_listeners: SubscriberSet::new(),
 487            focus_lost_listeners: SubscriberSet::new(),
 488            default_prevented: true,
 489            mouse_position,
 490            modifiers,
 491            scale_factor,
 492            bounds,
 493            bounds_observers: SubscriberSet::new(),
 494            active: false,
 495            dirty: false,
 496            refreshing: false,
 497            drawing: false,
 498            activation_observers: SubscriberSet::new(),
 499            focus: None,
 500            focus_enabled: true,
 501
 502            #[cfg(any(test, feature = "test-support"))]
 503            focus_invalidated: false,
 504        }
 505    }
 506}
 507
 508/// Indicates which region of the window is visible. Content falling outside of this mask will not be
 509/// rendered. Currently, only rectangular content masks are supported, but we give the mask its own type
 510/// to leave room to support more complex shapes in the future.
 511#[derive(Clone, Debug, Default, PartialEq, Eq)]
 512#[repr(C)]
 513pub struct ContentMask<P: Clone + Default + Debug> {
 514    /// The bounds
 515    pub bounds: Bounds<P>,
 516}
 517
 518impl ContentMask<Pixels> {
 519    /// Scale the content mask's pixel units by the given scaling factor.
 520    pub fn scale(&self, factor: f32) -> ContentMask<ScaledPixels> {
 521        ContentMask {
 522            bounds: self.bounds.scale(factor),
 523        }
 524    }
 525
 526    /// Intersect the content mask with the given content mask.
 527    pub fn intersect(&self, other: &Self) -> Self {
 528        let bounds = self.bounds.intersect(&other.bounds);
 529        ContentMask { bounds }
 530    }
 531}
 532
 533/// Provides access to application state in the context of a single window. Derefs
 534/// to an [`AppContext`], so you can also pass a [`WindowContext`] to any method that takes
 535/// an [`AppContext`] and call any [`AppContext`] methods.
 536pub struct WindowContext<'a> {
 537    pub(crate) app: &'a mut AppContext,
 538    pub(crate) window: &'a mut Window,
 539}
 540
 541impl<'a> WindowContext<'a> {
 542    pub(crate) fn new(app: &'a mut AppContext, window: &'a mut Window) -> Self {
 543        Self { app, window }
 544    }
 545
 546    /// Obtain a handle to the window that belongs to this context.
 547    pub fn window_handle(&self) -> AnyWindowHandle {
 548        self.window.handle
 549    }
 550
 551    /// Mark the window as dirty, scheduling it to be redrawn on the next frame.
 552    pub fn refresh(&mut self) {
 553        if !self.window.drawing {
 554            self.window.refreshing = true;
 555            self.window.dirty = true;
 556        }
 557    }
 558
 559    /// Close this window.
 560    pub fn remove_window(&mut self) {
 561        self.window.removed = true;
 562    }
 563
 564    /// Obtain a new [`FocusHandle`], which allows you to track and manipulate the keyboard focus
 565    /// for elements rendered within this window.
 566    pub fn focus_handle(&mut self) -> FocusHandle {
 567        FocusHandle::new(&self.window.focus_handles)
 568    }
 569
 570    /// Obtain the currently focused [`FocusHandle`]. If no elements are focused, returns `None`.
 571    pub fn focused(&self) -> Option<FocusHandle> {
 572        self.window
 573            .focus
 574            .and_then(|id| FocusHandle::for_id(id, &self.window.focus_handles))
 575    }
 576
 577    /// Move focus to the element associated with the given [`FocusHandle`].
 578    pub fn focus(&mut self, handle: &FocusHandle) {
 579        if !self.window.focus_enabled || self.window.focus == Some(handle.id) {
 580            return;
 581        }
 582
 583        self.window.focus = Some(handle.id);
 584        self.window
 585            .rendered_frame
 586            .dispatch_tree
 587            .clear_pending_keystrokes();
 588
 589        #[cfg(any(test, feature = "test-support"))]
 590        {
 591            self.window.focus_invalidated = true;
 592        }
 593
 594        self.refresh();
 595    }
 596
 597    /// Remove focus from all elements within this context's window.
 598    pub fn blur(&mut self) {
 599        if !self.window.focus_enabled {
 600            return;
 601        }
 602
 603        self.window.focus = None;
 604        self.refresh();
 605    }
 606
 607    /// Blur the window and don't allow anything in it to be focused again.
 608    pub fn disable_focus(&mut self) {
 609        self.blur();
 610        self.window.focus_enabled = false;
 611    }
 612
 613    /// Dispatch the given action on the currently focused element.
 614    pub fn dispatch_action(&mut self, action: Box<dyn Action>) {
 615        let focus_handle = self.focused();
 616
 617        self.defer(move |cx| {
 618            let node_id = focus_handle
 619                .and_then(|handle| {
 620                    cx.window
 621                        .rendered_frame
 622                        .dispatch_tree
 623                        .focusable_node_id(handle.id)
 624                })
 625                .unwrap_or_else(|| cx.window.rendered_frame.dispatch_tree.root_node_id());
 626
 627            cx.propagate_event = true;
 628            cx.dispatch_action_on_node(node_id, action);
 629        })
 630    }
 631
 632    pub(crate) fn dispatch_keystroke_observers(
 633        &mut self,
 634        event: &dyn Any,
 635        action: Option<Box<dyn Action>>,
 636    ) {
 637        let Some(key_down_event) = event.downcast_ref::<KeyDownEvent>() else {
 638            return;
 639        };
 640
 641        self.keystroke_observers
 642            .clone()
 643            .retain(&(), move |callback| {
 644                (callback)(
 645                    &KeystrokeEvent {
 646                        keystroke: key_down_event.keystroke.clone(),
 647                        action: action.as_ref().map(|action| action.boxed_clone()),
 648                    },
 649                    self,
 650                );
 651                true
 652            });
 653    }
 654
 655    pub(crate) fn clear_pending_keystrokes(&mut self) {
 656        self.window
 657            .rendered_frame
 658            .dispatch_tree
 659            .clear_pending_keystrokes();
 660        self.window
 661            .next_frame
 662            .dispatch_tree
 663            .clear_pending_keystrokes();
 664    }
 665
 666    /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
 667    /// that are currently on the stack to be returned to the app.
 668    pub fn defer(&mut self, f: impl FnOnce(&mut WindowContext) + 'static) {
 669        let handle = self.window.handle;
 670        self.app.defer(move |cx| {
 671            handle.update(cx, |_, cx| f(cx)).ok();
 672        });
 673    }
 674
 675    /// Subscribe to events emitted by a model or view.
 676    /// The entity to which you're subscribing must implement the [`EventEmitter`] trait.
 677    /// The callback will be invoked a handle to the emitting entity (either a [`View`] or [`Model`]), the event, and a window context for the current window.
 678    pub fn subscribe<Emitter, E, Evt>(
 679        &mut self,
 680        entity: &E,
 681        mut on_event: impl FnMut(E, &Evt, &mut WindowContext<'_>) + 'static,
 682    ) -> Subscription
 683    where
 684        Emitter: EventEmitter<Evt>,
 685        E: Entity<Emitter>,
 686        Evt: 'static,
 687    {
 688        let entity_id = entity.entity_id();
 689        let entity = entity.downgrade();
 690        let window_handle = self.window.handle;
 691        let (subscription, activate) = self.app.event_listeners.insert(
 692            entity_id,
 693            (
 694                TypeId::of::<Evt>(),
 695                Box::new(move |event, cx| {
 696                    window_handle
 697                        .update(cx, |_, cx| {
 698                            if let Some(handle) = E::upgrade_from(&entity) {
 699                                let event = event.downcast_ref().expect("invalid event type");
 700                                on_event(handle, event, cx);
 701                                true
 702                            } else {
 703                                false
 704                            }
 705                        })
 706                        .unwrap_or(false)
 707                }),
 708            ),
 709        );
 710        self.app.defer(move |_| activate());
 711        subscription
 712    }
 713
 714    /// Create an `AsyncWindowContext`, which has a static lifetime and can be held across
 715    /// await points in async code.
 716    pub fn to_async(&self) -> AsyncWindowContext {
 717        AsyncWindowContext::new(self.app.to_async(), self.window.handle)
 718    }
 719
 720    /// Schedule the given closure to be run directly after the current frame is rendered.
 721    pub fn on_next_frame(&mut self, callback: impl FnOnce(&mut WindowContext) + 'static) {
 722        let handle = self.window.handle;
 723        let display_id = self.window.display_id;
 724
 725        let mut frame_consumers = std::mem::take(&mut self.app.frame_consumers);
 726        if let Entry::Vacant(e) = frame_consumers.entry(display_id) {
 727            let (tx, mut rx) = mpsc::unbounded::<()>();
 728            self.platform.set_display_link_output_callback(
 729                display_id,
 730                Box::new(move |_current_time, _output_time| _ = tx.unbounded_send(())),
 731            );
 732
 733            let consumer_task = self.app.spawn(|cx| async move {
 734                while rx.next().await.is_some() {
 735                    cx.update(|cx| {
 736                        for callback in cx
 737                            .next_frame_callbacks
 738                            .get_mut(&display_id)
 739                            .unwrap()
 740                            .drain(..)
 741                            .collect::<SmallVec<[_; 32]>>()
 742                        {
 743                            callback(cx);
 744                        }
 745                    })
 746                    .ok();
 747
 748                    // Flush effects, then stop the display link if no new next_frame_callbacks have been added.
 749
 750                    cx.update(|cx| {
 751                        if cx.next_frame_callbacks.is_empty() {
 752                            cx.platform.stop_display_link(display_id);
 753                        }
 754                    })
 755                    .ok();
 756                }
 757            });
 758            e.insert(consumer_task);
 759        }
 760        debug_assert!(self.app.frame_consumers.is_empty());
 761        self.app.frame_consumers = frame_consumers;
 762
 763        if self.next_frame_callbacks.is_empty() {
 764            self.platform.start_display_link(display_id);
 765        }
 766
 767        self.next_frame_callbacks
 768            .entry(display_id)
 769            .or_default()
 770            .push(Box::new(move |cx: &mut AppContext| {
 771                cx.update_window(handle, |_root_view, cx| callback(cx)).ok();
 772            }));
 773    }
 774
 775    /// Spawn the future returned by the given closure on the application thread pool.
 776    /// The closure is provided a handle to the current window and an `AsyncWindowContext` for
 777    /// use within your future.
 778    pub fn spawn<Fut, R>(&mut self, f: impl FnOnce(AsyncWindowContext) -> Fut) -> Task<R>
 779    where
 780        R: 'static,
 781        Fut: Future<Output = R> + 'static,
 782    {
 783        self.app
 784            .spawn(|app| f(AsyncWindowContext::new(app, self.window.handle)))
 785    }
 786
 787    /// Update the global of the given type. The given closure is given simultaneous mutable
 788    /// access both to the global and the context.
 789    pub fn update_global<G, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R
 790    where
 791        G: 'static,
 792    {
 793        let mut global = self.app.lease_global::<G>();
 794        let result = f(&mut global, self);
 795        self.app.end_global_lease(global);
 796        result
 797    }
 798
 799    #[must_use]
 800    /// Add a node to the layout tree for the current frame. Takes the `Style` of the element for which
 801    /// layout is being requested, along with the layout ids of any children. This method is called during
 802    /// calls to the `Element::layout` trait method and enables any element to participate in layout.
 803    pub fn request_layout(
 804        &mut self,
 805        style: &Style,
 806        children: impl IntoIterator<Item = LayoutId>,
 807    ) -> LayoutId {
 808        self.app.layout_id_buffer.clear();
 809        self.app.layout_id_buffer.extend(children);
 810        let rem_size = self.rem_size();
 811
 812        self.window.layout_engine.as_mut().unwrap().request_layout(
 813            style,
 814            rem_size,
 815            &self.app.layout_id_buffer,
 816        )
 817    }
 818
 819    /// Add a node to the layout tree for the current frame. Instead of taking a `Style` and children,
 820    /// this variant takes a function that is invoked during layout so you can use arbitrary logic to
 821    /// determine the element's size. One place this is used internally is when measuring text.
 822    ///
 823    /// The given closure is invoked at layout time with the known dimensions and available space and
 824    /// returns a `Size`.
 825    pub fn request_measured_layout<
 826        F: FnMut(Size<Option<Pixels>>, Size<AvailableSpace>, &mut WindowContext) -> Size<Pixels>
 827            + 'static,
 828    >(
 829        &mut self,
 830        style: Style,
 831        measure: F,
 832    ) -> LayoutId {
 833        let rem_size = self.rem_size();
 834        self.window
 835            .layout_engine
 836            .as_mut()
 837            .unwrap()
 838            .request_measured_layout(style, rem_size, measure)
 839    }
 840
 841    pub(crate) fn layout_style(&self, layout_id: LayoutId) -> Option<&Style> {
 842        self.window
 843            .layout_engine
 844            .as_ref()
 845            .unwrap()
 846            .requested_style(layout_id)
 847    }
 848
 849    /// Compute the layout for the given id within the given available space.
 850    /// This method is called for its side effect, typically by the framework prior to painting.
 851    /// After calling it, you can request the bounds of the given layout node id or any descendant.
 852    pub fn compute_layout(&mut self, layout_id: LayoutId, available_space: Size<AvailableSpace>) {
 853        let mut layout_engine = self.window.layout_engine.take().unwrap();
 854        layout_engine.compute_layout(layout_id, available_space, self);
 855        self.window.layout_engine = Some(layout_engine);
 856    }
 857
 858    /// Obtain the bounds computed for the given LayoutId relative to the window. This method should not
 859    /// be invoked until the paint phase begins, and will usually be invoked by GPUI itself automatically
 860    /// in order to pass your element its `Bounds` automatically.
 861    pub fn layout_bounds(&mut self, layout_id: LayoutId) -> Bounds<Pixels> {
 862        let mut bounds = self
 863            .window
 864            .layout_engine
 865            .as_mut()
 866            .unwrap()
 867            .layout_bounds(layout_id)
 868            .map(Into::into);
 869        bounds.origin += self.element_offset();
 870        bounds
 871    }
 872
 873    fn window_bounds_changed(&mut self) {
 874        self.window.scale_factor = self.window.platform_window.scale_factor();
 875        self.window.viewport_size = self.window.platform_window.content_size();
 876        self.window.bounds = self.window.platform_window.bounds();
 877        self.window.display_id = self.window.platform_window.display().id();
 878        self.refresh();
 879
 880        self.window
 881            .bounds_observers
 882            .clone()
 883            .retain(&(), |callback| callback(self));
 884    }
 885
 886    /// Returns the bounds of the current window in the global coordinate space, which could span across multiple displays.
 887    pub fn window_bounds(&self) -> WindowBounds {
 888        self.window.bounds
 889    }
 890
 891    /// Returns the size of the drawable area within the window.
 892    pub fn viewport_size(&self) -> Size<Pixels> {
 893        self.window.viewport_size
 894    }
 895
 896    /// Returns whether this window is focused by the operating system (receiving key events).
 897    pub fn is_window_active(&self) -> bool {
 898        self.window.active
 899    }
 900
 901    /// Toggle zoom on the window.
 902    pub fn zoom_window(&self) {
 903        self.window.platform_window.zoom();
 904    }
 905
 906    /// Update the window's title at the platform level.
 907    pub fn set_window_title(&mut self, title: &str) {
 908        self.window.platform_window.set_title(title);
 909    }
 910
 911    /// Mark the window as dirty at the platform level.
 912    pub fn set_window_edited(&mut self, edited: bool) {
 913        self.window.platform_window.set_edited(edited);
 914    }
 915
 916    /// Determine the display on which the window is visible.
 917    pub fn display(&self) -> Option<Rc<dyn PlatformDisplay>> {
 918        self.platform
 919            .displays()
 920            .into_iter()
 921            .find(|display| display.id() == self.window.display_id)
 922    }
 923
 924    /// Show the platform character palette.
 925    pub fn show_character_palette(&self) {
 926        self.window.platform_window.show_character_palette();
 927    }
 928
 929    /// The scale factor of the display associated with the window. For example, it could
 930    /// return 2.0 for a "retina" display, indicating that each logical pixel should actually
 931    /// be rendered as two pixels on screen.
 932    pub fn scale_factor(&self) -> f32 {
 933        self.window.scale_factor
 934    }
 935
 936    /// The size of an em for the base font of the application. Adjusting this value allows the
 937    /// UI to scale, just like zooming a web page.
 938    pub fn rem_size(&self) -> Pixels {
 939        self.window.rem_size
 940    }
 941
 942    /// Sets the size of an em for the base font of the application. Adjusting this value allows the
 943    /// UI to scale, just like zooming a web page.
 944    pub fn set_rem_size(&mut self, rem_size: impl Into<Pixels>) {
 945        self.window.rem_size = rem_size.into();
 946    }
 947
 948    /// The line height associated with the current text style.
 949    pub fn line_height(&self) -> Pixels {
 950        let rem_size = self.rem_size();
 951        let text_style = self.text_style();
 952        text_style
 953            .line_height
 954            .to_pixels(text_style.font_size, rem_size)
 955    }
 956
 957    /// Call to prevent the default action of an event. Currently only used to prevent
 958    /// parent elements from becoming focused on mouse down.
 959    pub fn prevent_default(&mut self) {
 960        self.window.default_prevented = true;
 961    }
 962
 963    /// Obtain whether default has been prevented for the event currently being dispatched.
 964    pub fn default_prevented(&self) -> bool {
 965        self.window.default_prevented
 966    }
 967
 968    /// Register a mouse event listener on the window for the next frame. The type of event
 969    /// is determined by the first parameter of the given listener. When the next frame is rendered
 970    /// the listener will be cleared.
 971    pub fn on_mouse_event<Event: 'static>(
 972        &mut self,
 973        mut handler: impl FnMut(&Event, DispatchPhase, &mut WindowContext) + 'static,
 974    ) {
 975        let view_id = self.parent_view_id();
 976        let order = self.window.next_frame.z_index_stack.clone();
 977        self.window
 978            .next_frame
 979            .mouse_listeners
 980            .entry(TypeId::of::<Event>())
 981            .or_default()
 982            .push((
 983                order,
 984                view_id,
 985                Box::new(
 986                    move |event: &dyn Any, phase: DispatchPhase, cx: &mut WindowContext<'_>| {
 987                        handler(event.downcast_ref().unwrap(), phase, cx)
 988                    },
 989                ),
 990            ))
 991    }
 992
 993    /// Register a key event listener on the window for the next frame. The type of event
 994    /// is determined by the first parameter of the given listener. When the next frame is rendered
 995    /// the listener will be cleared.
 996    ///
 997    /// This is a fairly low-level method, so prefer using event handlers on elements unless you have
 998    /// a specific need to register a global listener.
 999    pub fn on_key_event<Event: 'static>(
1000        &mut self,
1001        listener: impl Fn(&Event, DispatchPhase, &mut WindowContext) + 'static,
1002    ) {
1003        self.window.next_frame.dispatch_tree.on_key_event(Rc::new(
1004            move |event: &dyn Any, phase, cx: &mut WindowContext<'_>| {
1005                if let Some(event) = event.downcast_ref::<Event>() {
1006                    listener(event, phase, cx)
1007                }
1008            },
1009        ));
1010    }
1011
1012    /// Register an action listener on the window for the next frame. The type of action
1013    /// is determined by the first parameter of the given listener. When the next frame is rendered
1014    /// the listener will be cleared.
1015    ///
1016    /// This is a fairly low-level method, so prefer using action handlers on elements unless you have
1017    /// a specific need to register a global listener.
1018    pub fn on_action(
1019        &mut self,
1020        action_type: TypeId,
1021        listener: impl Fn(&dyn Any, DispatchPhase, &mut WindowContext) + 'static,
1022    ) {
1023        self.window
1024            .next_frame
1025            .dispatch_tree
1026            .on_action(action_type, Rc::new(listener));
1027    }
1028
1029    /// Determine whether the given action is available along the dispatch path to the currently focused element.
1030    pub fn is_action_available(&self, action: &dyn Action) -> bool {
1031        let target = self
1032            .focused()
1033            .and_then(|focused_handle| {
1034                self.window
1035                    .rendered_frame
1036                    .dispatch_tree
1037                    .focusable_node_id(focused_handle.id)
1038            })
1039            .unwrap_or_else(|| self.window.rendered_frame.dispatch_tree.root_node_id());
1040        self.window
1041            .rendered_frame
1042            .dispatch_tree
1043            .is_action_available(action, target)
1044    }
1045
1046    /// The position of the mouse relative to the window.
1047    pub fn mouse_position(&self) -> Point<Pixels> {
1048        self.window.mouse_position
1049    }
1050
1051    /// The current state of the keyboard's modifiers
1052    pub fn modifiers(&self) -> Modifiers {
1053        self.window.modifiers
1054    }
1055
1056    /// Update the cursor style at the platform level.
1057    pub fn set_cursor_style(&mut self, style: CursorStyle) {
1058        let view_id = self.parent_view_id();
1059        self.window.next_frame.cursor_styles.insert(view_id, style);
1060        self.window.next_frame.requested_cursor_style = Some(style);
1061    }
1062
1063    /// Set a tooltip to be rendered for the upcoming frame
1064    pub fn set_tooltip(&mut self, tooltip: AnyTooltip) {
1065        let view_id = self.parent_view_id();
1066        self.window.next_frame.tooltip_request = Some(TooltipRequest { view_id, tooltip });
1067    }
1068
1069    /// Called during painting to track which z-index is on top at each pixel position
1070    pub fn add_opaque_layer(&mut self, bounds: Bounds<Pixels>) {
1071        let stacking_order = self.window.next_frame.z_index_stack.clone();
1072        let view_id = self.parent_view_id();
1073        let depth_map = &mut self.window.next_frame.depth_map;
1074        match depth_map.binary_search_by(|(level, _, _)| stacking_order.cmp(level)) {
1075            Ok(i) | Err(i) => depth_map.insert(i, (stacking_order, view_id, bounds)),
1076        }
1077    }
1078
1079    /// Returns true if there is no opaque layer containing the given point
1080    /// on top of the given level. Layers whose level is an extension of the
1081    /// level are not considered to be on top of the level.
1082    pub fn was_top_layer(&self, point: &Point<Pixels>, level: &StackingOrder) -> bool {
1083        for (opaque_level, _, bounds) in self.window.rendered_frame.depth_map.iter() {
1084            if level >= opaque_level {
1085                break;
1086            }
1087
1088            if bounds.contains(point) && !opaque_level.starts_with(level) {
1089                return false;
1090            }
1091        }
1092        true
1093    }
1094
1095    pub(crate) fn was_top_layer_under_active_drag(
1096        &self,
1097        point: &Point<Pixels>,
1098        level: &StackingOrder,
1099    ) -> bool {
1100        for (opaque_level, _, bounds) in self.window.rendered_frame.depth_map.iter() {
1101            if level >= opaque_level {
1102                break;
1103            }
1104            if opaque_level.starts_with(&[ACTIVE_DRAG_Z_INDEX]) {
1105                continue;
1106            }
1107
1108            if bounds.contains(point) && !opaque_level.starts_with(level) {
1109                return false;
1110            }
1111        }
1112        true
1113    }
1114
1115    /// Called during painting to get the current stacking order.
1116    pub fn stacking_order(&self) -> &StackingOrder {
1117        &self.window.next_frame.z_index_stack
1118    }
1119
1120    /// Paint one or more drop shadows into the scene for the next frame at the current z-index.
1121    pub fn paint_shadows(
1122        &mut self,
1123        bounds: Bounds<Pixels>,
1124        corner_radii: Corners<Pixels>,
1125        shadows: &[BoxShadow],
1126    ) {
1127        let scale_factor = self.scale_factor();
1128        let content_mask = self.content_mask();
1129        let view_id = self.parent_view_id();
1130        let window = &mut *self.window;
1131        for shadow in shadows {
1132            let mut shadow_bounds = bounds;
1133            shadow_bounds.origin += shadow.offset;
1134            shadow_bounds.dilate(shadow.spread_radius);
1135            window.next_frame.scene.insert(
1136                &window.next_frame.z_index_stack,
1137                Shadow {
1138                    view_id: view_id.into(),
1139                    layer_id: 0,
1140                    order: 0,
1141                    bounds: shadow_bounds.scale(scale_factor),
1142                    content_mask: content_mask.scale(scale_factor),
1143                    corner_radii: corner_radii.scale(scale_factor),
1144                    color: shadow.color,
1145                    blur_radius: shadow.blur_radius.scale(scale_factor),
1146                },
1147            );
1148        }
1149    }
1150
1151    /// Paint one or more quads into the scene for the next frame at the current stacking context.
1152    /// Quads are colored rectangular regions with an optional background, border, and corner radius.
1153    /// see [`fill`], [`outline`], and [`quad`] to construct this type.
1154    pub fn paint_quad(&mut self, quad: PaintQuad) {
1155        let scale_factor = self.scale_factor();
1156        let content_mask = self.content_mask();
1157        let view_id = self.parent_view_id();
1158
1159        let window = &mut *self.window;
1160        window.next_frame.scene.insert(
1161            &window.next_frame.z_index_stack,
1162            Quad {
1163                view_id: view_id.into(),
1164                layer_id: 0,
1165                order: 0,
1166                bounds: quad.bounds.scale(scale_factor),
1167                content_mask: content_mask.scale(scale_factor),
1168                background: quad.background,
1169                border_color: quad.border_color,
1170                corner_radii: quad.corner_radii.scale(scale_factor),
1171                border_widths: quad.border_widths.scale(scale_factor),
1172            },
1173        );
1174    }
1175
1176    /// Paint the given `Path` into the scene for the next frame at the current z-index.
1177    pub fn paint_path(&mut self, mut path: Path<Pixels>, color: impl Into<Hsla>) {
1178        let scale_factor = self.scale_factor();
1179        let content_mask = self.content_mask();
1180        let view_id = self.parent_view_id();
1181
1182        path.content_mask = content_mask;
1183        path.color = color.into();
1184        path.view_id = view_id.into();
1185        let window = &mut *self.window;
1186        window
1187            .next_frame
1188            .scene
1189            .insert(&window.next_frame.z_index_stack, path.scale(scale_factor));
1190    }
1191
1192    /// Paint an underline into the scene for the next frame at the current z-index.
1193    pub fn paint_underline(
1194        &mut self,
1195        origin: Point<Pixels>,
1196        width: Pixels,
1197        style: &UnderlineStyle,
1198    ) {
1199        let scale_factor = self.scale_factor();
1200        let height = if style.wavy {
1201            style.thickness * 3.
1202        } else {
1203            style.thickness
1204        };
1205        let bounds = Bounds {
1206            origin,
1207            size: size(width, height),
1208        };
1209        let content_mask = self.content_mask();
1210        let view_id = self.parent_view_id();
1211
1212        let window = &mut *self.window;
1213        window.next_frame.scene.insert(
1214            &window.next_frame.z_index_stack,
1215            Underline {
1216                view_id: view_id.into(),
1217                layer_id: 0,
1218                order: 0,
1219                bounds: bounds.scale(scale_factor),
1220                content_mask: content_mask.scale(scale_factor),
1221                thickness: style.thickness.scale(scale_factor),
1222                color: style.color.unwrap_or_default(),
1223                wavy: style.wavy,
1224            },
1225        );
1226    }
1227
1228    /// Paint a monochrome (non-emoji) glyph into the scene for the next frame at the current z-index.
1229    /// The y component of the origin is the baseline of the glyph.
1230    pub fn paint_glyph(
1231        &mut self,
1232        origin: Point<Pixels>,
1233        font_id: FontId,
1234        glyph_id: GlyphId,
1235        font_size: Pixels,
1236        color: Hsla,
1237    ) -> Result<()> {
1238        let scale_factor = self.scale_factor();
1239        let glyph_origin = origin.scale(scale_factor);
1240        let subpixel_variant = Point {
1241            x: (glyph_origin.x.0.fract() * SUBPIXEL_VARIANTS as f32).floor() as u8,
1242            y: (glyph_origin.y.0.fract() * SUBPIXEL_VARIANTS as f32).floor() as u8,
1243        };
1244        let params = RenderGlyphParams {
1245            font_id,
1246            glyph_id,
1247            font_size,
1248            subpixel_variant,
1249            scale_factor,
1250            is_emoji: false,
1251        };
1252
1253        let raster_bounds = self.text_system().raster_bounds(&params)?;
1254        if !raster_bounds.is_zero() {
1255            let tile =
1256                self.window
1257                    .sprite_atlas
1258                    .get_or_insert_with(&params.clone().into(), &mut || {
1259                        let (size, bytes) = self.text_system().rasterize_glyph(&params)?;
1260                        Ok((size, Cow::Owned(bytes)))
1261                    })?;
1262            let bounds = Bounds {
1263                origin: glyph_origin.map(|px| px.floor()) + raster_bounds.origin.map(Into::into),
1264                size: tile.bounds.size.map(Into::into),
1265            };
1266            let content_mask = self.content_mask().scale(scale_factor);
1267            let view_id = self.parent_view_id();
1268            let window = &mut *self.window;
1269            window.next_frame.scene.insert(
1270                &window.next_frame.z_index_stack,
1271                MonochromeSprite {
1272                    view_id: view_id.into(),
1273                    layer_id: 0,
1274                    order: 0,
1275                    bounds,
1276                    content_mask,
1277                    color,
1278                    tile,
1279                },
1280            );
1281        }
1282        Ok(())
1283    }
1284
1285    /// Paint an emoji glyph into the scene for the next frame at the current z-index.
1286    /// The y component of the origin is the baseline of the glyph.
1287    pub fn paint_emoji(
1288        &mut self,
1289        origin: Point<Pixels>,
1290        font_id: FontId,
1291        glyph_id: GlyphId,
1292        font_size: Pixels,
1293    ) -> Result<()> {
1294        let scale_factor = self.scale_factor();
1295        let glyph_origin = origin.scale(scale_factor);
1296        let params = RenderGlyphParams {
1297            font_id,
1298            glyph_id,
1299            font_size,
1300            // We don't render emojis with subpixel variants.
1301            subpixel_variant: Default::default(),
1302            scale_factor,
1303            is_emoji: true,
1304        };
1305
1306        let raster_bounds = self.text_system().raster_bounds(&params)?;
1307        if !raster_bounds.is_zero() {
1308            let tile =
1309                self.window
1310                    .sprite_atlas
1311                    .get_or_insert_with(&params.clone().into(), &mut || {
1312                        let (size, bytes) = self.text_system().rasterize_glyph(&params)?;
1313                        Ok((size, Cow::Owned(bytes)))
1314                    })?;
1315            let bounds = Bounds {
1316                origin: glyph_origin.map(|px| px.floor()) + raster_bounds.origin.map(Into::into),
1317                size: tile.bounds.size.map(Into::into),
1318            };
1319            let content_mask = self.content_mask().scale(scale_factor);
1320            let view_id = self.parent_view_id();
1321            let window = &mut *self.window;
1322
1323            window.next_frame.scene.insert(
1324                &window.next_frame.z_index_stack,
1325                PolychromeSprite {
1326                    view_id: view_id.into(),
1327                    layer_id: 0,
1328                    order: 0,
1329                    bounds,
1330                    corner_radii: Default::default(),
1331                    content_mask,
1332                    tile,
1333                    grayscale: false,
1334                },
1335            );
1336        }
1337        Ok(())
1338    }
1339
1340    /// Paint a monochrome SVG into the scene for the next frame at the current stacking context.
1341    pub fn paint_svg(
1342        &mut self,
1343        bounds: Bounds<Pixels>,
1344        path: SharedString,
1345        color: Hsla,
1346    ) -> Result<()> {
1347        let scale_factor = self.scale_factor();
1348        let bounds = bounds.scale(scale_factor);
1349        // Render the SVG at twice the size to get a higher quality result.
1350        let params = RenderSvgParams {
1351            path,
1352            size: bounds
1353                .size
1354                .map(|pixels| DevicePixels::from((pixels.0 * 2.).ceil() as i32)),
1355        };
1356
1357        let tile =
1358            self.window
1359                .sprite_atlas
1360                .get_or_insert_with(&params.clone().into(), &mut || {
1361                    let bytes = self.svg_renderer.render(&params)?;
1362                    Ok((params.size, Cow::Owned(bytes)))
1363                })?;
1364        let content_mask = self.content_mask().scale(scale_factor);
1365        let view_id = self.parent_view_id();
1366
1367        let window = &mut *self.window;
1368        window.next_frame.scene.insert(
1369            &window.next_frame.z_index_stack,
1370            MonochromeSprite {
1371                view_id: view_id.into(),
1372                layer_id: 0,
1373                order: 0,
1374                bounds,
1375                content_mask,
1376                color,
1377                tile,
1378            },
1379        );
1380
1381        Ok(())
1382    }
1383
1384    /// Paint an image into the scene for the next frame at the current z-index.
1385    pub fn paint_image(
1386        &mut self,
1387        bounds: Bounds<Pixels>,
1388        corner_radii: Corners<Pixels>,
1389        data: Arc<ImageData>,
1390        grayscale: bool,
1391    ) -> Result<()> {
1392        let scale_factor = self.scale_factor();
1393        let bounds = bounds.scale(scale_factor);
1394        let params = RenderImageParams { image_id: data.id };
1395
1396        let tile = self
1397            .window
1398            .sprite_atlas
1399            .get_or_insert_with(&params.clone().into(), &mut || {
1400                Ok((data.size(), Cow::Borrowed(data.as_bytes())))
1401            })?;
1402        let content_mask = self.content_mask().scale(scale_factor);
1403        let corner_radii = corner_radii.scale(scale_factor);
1404        let view_id = self.parent_view_id();
1405
1406        let window = &mut *self.window;
1407        window.next_frame.scene.insert(
1408            &window.next_frame.z_index_stack,
1409            PolychromeSprite {
1410                view_id: view_id.into(),
1411                layer_id: 0,
1412                order: 0,
1413                bounds,
1414                content_mask,
1415                corner_radii,
1416                tile,
1417                grayscale,
1418            },
1419        );
1420        Ok(())
1421    }
1422
1423    /// Paint a surface into the scene for the next frame at the current z-index.
1424    pub fn paint_surface(&mut self, bounds: Bounds<Pixels>, image_buffer: CVImageBuffer) {
1425        let scale_factor = self.scale_factor();
1426        let bounds = bounds.scale(scale_factor);
1427        let content_mask = self.content_mask().scale(scale_factor);
1428        let view_id = self.parent_view_id();
1429        let window = &mut *self.window;
1430        window.next_frame.scene.insert(
1431            &window.next_frame.z_index_stack,
1432            Surface {
1433                view_id: view_id.into(),
1434                layer_id: 0,
1435                order: 0,
1436                bounds,
1437                content_mask,
1438                image_buffer,
1439            },
1440        );
1441    }
1442
1443    pub(crate) fn reuse_view(&mut self) {
1444        let view_id = self.parent_view_id();
1445        let grafted_view_ids = self
1446            .window
1447            .next_frame
1448            .dispatch_tree
1449            .reuse_view(view_id, &mut self.window.rendered_frame.dispatch_tree);
1450        for view_id in grafted_view_ids {
1451            assert!(self.window.next_frame.reused_views.insert(view_id));
1452
1453            // Reuse the previous input handler requested during painting of the reused view.
1454            if self
1455                .window
1456                .rendered_frame
1457                .requested_input_handler
1458                .as_ref()
1459                .map_or(false, |requested| requested.view_id == view_id)
1460            {
1461                self.window.next_frame.requested_input_handler =
1462                    self.window.rendered_frame.requested_input_handler.take();
1463            }
1464
1465            // Reuse the tooltip previously requested during painting of the reused view.
1466            if self
1467                .window
1468                .rendered_frame
1469                .tooltip_request
1470                .as_ref()
1471                .map_or(false, |requested| requested.view_id == view_id)
1472            {
1473                self.window.next_frame.tooltip_request =
1474                    self.window.rendered_frame.tooltip_request.take();
1475            }
1476
1477            // Reuse the cursor styles previously requested during painting of the reused view.
1478            if let Some(style) = self.window.rendered_frame.cursor_styles.remove(&view_id) {
1479                self.window.next_frame.cursor_styles.insert(view_id, style);
1480                self.window.next_frame.requested_cursor_style = Some(style);
1481            }
1482        }
1483    }
1484
1485    /// Draw pixels to the display for this window based on the contents of its scene.
1486    pub(crate) fn draw(&mut self) {
1487        self.window.dirty = false;
1488        self.window.drawing = true;
1489
1490        #[cfg(any(test, feature = "test-support"))]
1491        {
1492            self.window.focus_invalidated = false;
1493        }
1494
1495        if let Some(requested_handler) = self.window.rendered_frame.requested_input_handler.as_mut()
1496        {
1497            requested_handler.handler = self.window.platform_window.take_input_handler();
1498        }
1499
1500        let root_view = self.window.root_view.take().unwrap();
1501
1502        self.with_z_index(0, |cx| {
1503            cx.with_key_dispatch(Some(KeyContext::default()), None, |_, cx| {
1504                for (action_type, action_listeners) in &cx.app.global_action_listeners {
1505                    for action_listener in action_listeners.iter().cloned() {
1506                        cx.window.next_frame.dispatch_tree.on_action(
1507                            *action_type,
1508                            Rc::new(move |action: &dyn Any, phase, cx: &mut WindowContext<'_>| {
1509                                action_listener(action, phase, cx)
1510                            }),
1511                        )
1512                    }
1513                }
1514
1515                let available_space = cx.window.viewport_size.map(Into::into);
1516                root_view.draw(Point::default(), available_space, cx);
1517            })
1518        });
1519
1520        if let Some(active_drag) = self.app.active_drag.take() {
1521            self.with_z_index(ACTIVE_DRAG_Z_INDEX, |cx| {
1522                let offset = cx.mouse_position() - active_drag.cursor_offset;
1523                let available_space = size(AvailableSpace::MinContent, AvailableSpace::MinContent);
1524                active_drag.view.draw(offset, available_space, cx);
1525            });
1526            self.active_drag = Some(active_drag);
1527        } else if let Some(tooltip_request) = self.window.next_frame.tooltip_request.take() {
1528            self.with_z_index(1, |cx| {
1529                let available_space = size(AvailableSpace::MinContent, AvailableSpace::MinContent);
1530                tooltip_request.tooltip.view.draw(
1531                    tooltip_request.tooltip.cursor_offset,
1532                    available_space,
1533                    cx,
1534                );
1535            });
1536            self.window.next_frame.tooltip_request = Some(tooltip_request);
1537        }
1538        self.window.dirty_views.clear();
1539
1540        self.window
1541            .next_frame
1542            .dispatch_tree
1543            .preserve_pending_keystrokes(
1544                &mut self.window.rendered_frame.dispatch_tree,
1545                self.window.focus,
1546            );
1547        self.window.next_frame.focus = self.window.focus;
1548        self.window.next_frame.window_active = self.window.active;
1549        self.window.root_view = Some(root_view);
1550
1551        // Set the cursor only if we're the active window.
1552        let cursor_style = self
1553            .window
1554            .next_frame
1555            .requested_cursor_style
1556            .take()
1557            .unwrap_or(CursorStyle::Arrow);
1558        if self.is_window_active() {
1559            self.platform.set_cursor_style(cursor_style);
1560        }
1561
1562        // Register requested input handler with the platform window.
1563        if let Some(requested_input) = self.window.next_frame.requested_input_handler.as_mut() {
1564            if let Some(handler) = requested_input.handler.take() {
1565                self.window.platform_window.set_input_handler(handler);
1566            }
1567        }
1568
1569        self.window.layout_engine.as_mut().unwrap().clear();
1570        self.text_system()
1571            .finish_frame(&self.window.next_frame.reused_views);
1572        self.window
1573            .next_frame
1574            .finish(&mut self.window.rendered_frame);
1575        ELEMENT_ARENA.with_borrow_mut(|element_arena| element_arena.clear());
1576
1577        let previous_focus_path = self.window.rendered_frame.focus_path();
1578        let previous_window_active = self.window.rendered_frame.window_active;
1579        mem::swap(&mut self.window.rendered_frame, &mut self.window.next_frame);
1580        self.window.next_frame.clear();
1581        let current_focus_path = self.window.rendered_frame.focus_path();
1582        let current_window_active = self.window.rendered_frame.window_active;
1583
1584        if previous_focus_path != current_focus_path
1585            || previous_window_active != current_window_active
1586        {
1587            if !previous_focus_path.is_empty() && current_focus_path.is_empty() {
1588                self.window
1589                    .focus_lost_listeners
1590                    .clone()
1591                    .retain(&(), |listener| listener(self));
1592            }
1593
1594            let event = FocusEvent {
1595                previous_focus_path: if previous_window_active {
1596                    previous_focus_path
1597                } else {
1598                    Default::default()
1599                },
1600                current_focus_path: if current_window_active {
1601                    current_focus_path
1602                } else {
1603                    Default::default()
1604                },
1605            };
1606            self.window
1607                .focus_listeners
1608                .clone()
1609                .retain(&(), |listener| listener(&event, self));
1610        }
1611
1612        self.window
1613            .platform_window
1614            .draw(&self.window.rendered_frame.scene);
1615        self.window.refreshing = false;
1616        self.window.drawing = false;
1617    }
1618
1619    /// Dispatch a mouse or keyboard event on the window.
1620    pub fn dispatch_event(&mut self, event: InputEvent) -> bool {
1621        // Handlers may set this to false by calling `stop_propagation`.
1622        self.app.propagate_event = true;
1623        // Handlers may set this to true by calling `prevent_default`.
1624        self.window.default_prevented = false;
1625
1626        let event = match event {
1627            // Track the mouse position with our own state, since accessing the platform
1628            // API for the mouse position can only occur on the main thread.
1629            InputEvent::MouseMove(mouse_move) => {
1630                self.window.mouse_position = mouse_move.position;
1631                self.window.modifiers = mouse_move.modifiers;
1632                InputEvent::MouseMove(mouse_move)
1633            }
1634            InputEvent::MouseDown(mouse_down) => {
1635                self.window.mouse_position = mouse_down.position;
1636                self.window.modifiers = mouse_down.modifiers;
1637                InputEvent::MouseDown(mouse_down)
1638            }
1639            InputEvent::MouseUp(mouse_up) => {
1640                self.window.mouse_position = mouse_up.position;
1641                self.window.modifiers = mouse_up.modifiers;
1642                InputEvent::MouseUp(mouse_up)
1643            }
1644            InputEvent::MouseExited(mouse_exited) => {
1645                self.window.modifiers = mouse_exited.modifiers;
1646                InputEvent::MouseExited(mouse_exited)
1647            }
1648            InputEvent::ModifiersChanged(modifiers_changed) => {
1649                self.window.modifiers = modifiers_changed.modifiers;
1650                InputEvent::ModifiersChanged(modifiers_changed)
1651            }
1652            InputEvent::ScrollWheel(scroll_wheel) => {
1653                self.window.mouse_position = scroll_wheel.position;
1654                self.window.modifiers = scroll_wheel.modifiers;
1655                InputEvent::ScrollWheel(scroll_wheel)
1656            }
1657            // Translate dragging and dropping of external files from the operating system
1658            // to internal drag and drop events.
1659            InputEvent::FileDrop(file_drop) => match file_drop {
1660                FileDropEvent::Entered { position, paths } => {
1661                    self.window.mouse_position = position;
1662                    if self.active_drag.is_none() {
1663                        self.active_drag = Some(AnyDrag {
1664                            value: Box::new(paths.clone()),
1665                            view: self.new_view(|_| paths).into(),
1666                            cursor_offset: position,
1667                        });
1668                    }
1669                    InputEvent::MouseMove(MouseMoveEvent {
1670                        position,
1671                        pressed_button: Some(MouseButton::Left),
1672                        modifiers: Modifiers::default(),
1673                    })
1674                }
1675                FileDropEvent::Pending { position } => {
1676                    self.window.mouse_position = position;
1677                    InputEvent::MouseMove(MouseMoveEvent {
1678                        position,
1679                        pressed_button: Some(MouseButton::Left),
1680                        modifiers: Modifiers::default(),
1681                    })
1682                }
1683                FileDropEvent::Submit { position } => {
1684                    self.activate(true);
1685                    self.window.mouse_position = position;
1686                    InputEvent::MouseUp(MouseUpEvent {
1687                        button: MouseButton::Left,
1688                        position,
1689                        modifiers: Modifiers::default(),
1690                        click_count: 1,
1691                    })
1692                }
1693                FileDropEvent::Exited => InputEvent::MouseUp(MouseUpEvent {
1694                    button: MouseButton::Left,
1695                    position: Point::default(),
1696                    modifiers: Modifiers::default(),
1697                    click_count: 1,
1698                }),
1699            },
1700            InputEvent::KeyDown(_) | InputEvent::KeyUp(_) => event,
1701        };
1702
1703        if let Some(any_mouse_event) = event.mouse_event() {
1704            self.dispatch_mouse_event(any_mouse_event);
1705        } else if let Some(any_key_event) = event.keyboard_event() {
1706            self.dispatch_key_event(any_key_event);
1707        }
1708
1709        !self.app.propagate_event
1710    }
1711
1712    fn dispatch_mouse_event(&mut self, event: &dyn Any) {
1713        if let Some(mut handlers) = self
1714            .window
1715            .rendered_frame
1716            .mouse_listeners
1717            .remove(&event.type_id())
1718        {
1719            // Because handlers may add other handlers, we sort every time.
1720            handlers.sort_by(|(a, _, _), (b, _, _)| a.cmp(b));
1721
1722            // Capture phase, events bubble from back to front. Handlers for this phase are used for
1723            // special purposes, such as detecting events outside of a given Bounds.
1724            for (_, _, handler) in &mut handlers {
1725                handler(event, DispatchPhase::Capture, self);
1726                if !self.app.propagate_event {
1727                    break;
1728                }
1729            }
1730
1731            // Bubble phase, where most normal handlers do their work.
1732            if self.app.propagate_event {
1733                for (_, _, handler) in handlers.iter_mut().rev() {
1734                    handler(event, DispatchPhase::Bubble, self);
1735                    if !self.app.propagate_event {
1736                        break;
1737                    }
1738                }
1739            }
1740
1741            self.window
1742                .rendered_frame
1743                .mouse_listeners
1744                .insert(event.type_id(), handlers);
1745        }
1746
1747        if self.app.propagate_event && self.has_active_drag() {
1748            if event.is::<MouseMoveEvent>() {
1749                // If this was a mouse move event, redraw the window so that the
1750                // active drag can follow the mouse cursor.
1751                self.refresh();
1752            } else if event.is::<MouseUpEvent>() {
1753                // If this was a mouse up event, cancel the active drag and redraw
1754                // the window.
1755                self.active_drag = None;
1756                self.refresh();
1757            }
1758        }
1759    }
1760
1761    fn dispatch_key_event(&mut self, event: &dyn Any) {
1762        let node_id = self
1763            .window
1764            .focus
1765            .and_then(|focus_id| {
1766                self.window
1767                    .rendered_frame
1768                    .dispatch_tree
1769                    .focusable_node_id(focus_id)
1770            })
1771            .unwrap_or_else(|| self.window.rendered_frame.dispatch_tree.root_node_id());
1772
1773        let dispatch_path = self
1774            .window
1775            .rendered_frame
1776            .dispatch_tree
1777            .dispatch_path(node_id);
1778
1779        let mut actions: Vec<Box<dyn Action>> = Vec::new();
1780
1781        let mut context_stack: SmallVec<[KeyContext; 16]> = SmallVec::new();
1782        for node_id in &dispatch_path {
1783            let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1784
1785            if let Some(context) = node.context.clone() {
1786                context_stack.push(context);
1787            }
1788        }
1789
1790        for node_id in dispatch_path.iter().rev() {
1791            // Match keystrokes
1792            let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1793            if node.context.is_some() {
1794                if let Some(key_down_event) = event.downcast_ref::<KeyDownEvent>() {
1795                    let mut new_actions = self
1796                        .window
1797                        .rendered_frame
1798                        .dispatch_tree
1799                        .dispatch_key(&key_down_event.keystroke, &context_stack);
1800                    actions.append(&mut new_actions);
1801                }
1802
1803                context_stack.pop();
1804            }
1805        }
1806
1807        if !actions.is_empty() {
1808            self.clear_pending_keystrokes();
1809        }
1810
1811        self.propagate_event = true;
1812        for action in actions {
1813            self.dispatch_action_on_node(node_id, action.boxed_clone());
1814            if !self.propagate_event {
1815                self.dispatch_keystroke_observers(event, Some(action));
1816                return;
1817            }
1818        }
1819
1820        // Capture phase
1821        for node_id in &dispatch_path {
1822            let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1823
1824            for key_listener in node.key_listeners.clone() {
1825                key_listener(event, DispatchPhase::Capture, self);
1826                if !self.propagate_event {
1827                    return;
1828                }
1829            }
1830        }
1831
1832        // Bubble phase
1833        for node_id in dispatch_path.iter().rev() {
1834            // Handle low level key events
1835            let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1836            for key_listener in node.key_listeners.clone() {
1837                key_listener(event, DispatchPhase::Bubble, self);
1838                if !self.propagate_event {
1839                    return;
1840                }
1841            }
1842        }
1843
1844        self.dispatch_keystroke_observers(event, None);
1845    }
1846
1847    /// Determine whether a potential multi-stroke key binding is in progress on this window.
1848    pub fn has_pending_keystrokes(&self) -> bool {
1849        self.window
1850            .rendered_frame
1851            .dispatch_tree
1852            .has_pending_keystrokes()
1853    }
1854
1855    fn dispatch_action_on_node(&mut self, node_id: DispatchNodeId, action: Box<dyn Action>) {
1856        let dispatch_path = self
1857            .window
1858            .rendered_frame
1859            .dispatch_tree
1860            .dispatch_path(node_id);
1861
1862        // Capture phase
1863        for node_id in &dispatch_path {
1864            let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1865            for DispatchActionListener {
1866                action_type,
1867                listener,
1868            } in node.action_listeners.clone()
1869            {
1870                let any_action = action.as_any();
1871                if action_type == any_action.type_id() {
1872                    listener(any_action, DispatchPhase::Capture, self);
1873                    if !self.propagate_event {
1874                        return;
1875                    }
1876                }
1877            }
1878        }
1879        // Bubble phase
1880        for node_id in dispatch_path.iter().rev() {
1881            let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1882            for DispatchActionListener {
1883                action_type,
1884                listener,
1885            } in node.action_listeners.clone()
1886            {
1887                let any_action = action.as_any();
1888                if action_type == any_action.type_id() {
1889                    self.propagate_event = false; // Actions stop propagation by default during the bubble phase
1890                    listener(any_action, DispatchPhase::Bubble, self);
1891                    if !self.propagate_event {
1892                        return;
1893                    }
1894                }
1895            }
1896        }
1897    }
1898
1899    /// Register the given handler to be invoked whenever the global of the given type
1900    /// is updated.
1901    pub fn observe_global<G: 'static>(
1902        &mut self,
1903        f: impl Fn(&mut WindowContext<'_>) + 'static,
1904    ) -> Subscription {
1905        let window_handle = self.window.handle;
1906        let (subscription, activate) = self.global_observers.insert(
1907            TypeId::of::<G>(),
1908            Box::new(move |cx| window_handle.update(cx, |_, cx| f(cx)).is_ok()),
1909        );
1910        self.app.defer(move |_| activate());
1911        subscription
1912    }
1913
1914    /// Focus the current window and bring it to the foreground at the platform level.
1915    pub fn activate_window(&self) {
1916        self.window.platform_window.activate();
1917    }
1918
1919    /// Minimize the current window at the platform level.
1920    pub fn minimize_window(&self) {
1921        self.window.platform_window.minimize();
1922    }
1923
1924    /// Toggle full screen status on the current window at the platform level.
1925    pub fn toggle_full_screen(&self) {
1926        self.window.platform_window.toggle_full_screen();
1927    }
1928
1929    /// Present a platform dialog.
1930    /// The provided message will be presented, along with buttons for each answer.
1931    /// When a button is clicked, the returned Receiver will receive the index of the clicked button.
1932    pub fn prompt(
1933        &self,
1934        level: PromptLevel,
1935        message: &str,
1936        answers: &[&str],
1937    ) -> oneshot::Receiver<usize> {
1938        self.window.platform_window.prompt(level, message, answers)
1939    }
1940
1941    /// Returns all available actions for the focused element.
1942    pub fn available_actions(&self) -> Vec<Box<dyn Action>> {
1943        let node_id = self
1944            .window
1945            .focus
1946            .and_then(|focus_id| {
1947                self.window
1948                    .rendered_frame
1949                    .dispatch_tree
1950                    .focusable_node_id(focus_id)
1951            })
1952            .unwrap_or_else(|| self.window.rendered_frame.dispatch_tree.root_node_id());
1953
1954        self.window
1955            .rendered_frame
1956            .dispatch_tree
1957            .available_actions(node_id)
1958    }
1959
1960    /// Returns key bindings that invoke the given action on the currently focused element.
1961    pub fn bindings_for_action(&self, action: &dyn Action) -> Vec<KeyBinding> {
1962        self.window
1963            .rendered_frame
1964            .dispatch_tree
1965            .bindings_for_action(
1966                action,
1967                &self.window.rendered_frame.dispatch_tree.context_stack,
1968            )
1969    }
1970
1971    /// Returns any bindings that would invoke the given action on the given focus handle if it were focused.
1972    pub fn bindings_for_action_in(
1973        &self,
1974        action: &dyn Action,
1975        focus_handle: &FocusHandle,
1976    ) -> Vec<KeyBinding> {
1977        let dispatch_tree = &self.window.rendered_frame.dispatch_tree;
1978
1979        let Some(node_id) = dispatch_tree.focusable_node_id(focus_handle.id) else {
1980            return vec![];
1981        };
1982        let context_stack = dispatch_tree
1983            .dispatch_path(node_id)
1984            .into_iter()
1985            .filter_map(|node_id| dispatch_tree.node(node_id).context.clone())
1986            .collect();
1987        dispatch_tree.bindings_for_action(action, &context_stack)
1988    }
1989
1990    /// Returns a generic event listener that invokes the given listener with the view and context associated with the given view handle.
1991    pub fn listener_for<V: Render, E>(
1992        &self,
1993        view: &View<V>,
1994        f: impl Fn(&mut V, &E, &mut ViewContext<V>) + 'static,
1995    ) -> impl Fn(&E, &mut WindowContext) + 'static {
1996        let view = view.downgrade();
1997        move |e: &E, cx: &mut WindowContext| {
1998            view.update(cx, |view, cx| f(view, e, cx)).ok();
1999        }
2000    }
2001
2002    /// Returns a generic handler that invokes the given handler with the view and context associated with the given view handle.
2003    pub fn handler_for<V: Render>(
2004        &self,
2005        view: &View<V>,
2006        f: impl Fn(&mut V, &mut ViewContext<V>) + 'static,
2007    ) -> impl Fn(&mut WindowContext) {
2008        let view = view.downgrade();
2009        move |cx: &mut WindowContext| {
2010            view.update(cx, |view, cx| f(view, cx)).ok();
2011        }
2012    }
2013
2014    /// Invoke the given function with the given focus handle present on the key dispatch stack.
2015    /// If you want an element to participate in key dispatch, use this method to push its key context and focus handle into the stack during paint.
2016    pub fn with_key_dispatch<R>(
2017        &mut self,
2018        context: Option<KeyContext>,
2019        focus_handle: Option<FocusHandle>,
2020        f: impl FnOnce(Option<FocusHandle>, &mut Self) -> R,
2021    ) -> R {
2022        let window = &mut self.window;
2023        let focus_id = focus_handle.as_ref().map(|handle| handle.id);
2024        window
2025            .next_frame
2026            .dispatch_tree
2027            .push_node(context.clone(), focus_id, None);
2028
2029        let result = f(focus_handle, self);
2030
2031        self.window.next_frame.dispatch_tree.pop_node();
2032
2033        result
2034    }
2035
2036    /// Invoke the given function with the given view id present on the view stack.
2037    /// This is a fairly low-level method used to layout views.
2038    pub fn with_view_id<R>(&mut self, view_id: EntityId, f: impl FnOnce(&mut Self) -> R) -> R {
2039        let text_system = self.text_system().clone();
2040        text_system.with_view(view_id, || {
2041            if self.window.next_frame.view_stack.last() == Some(&view_id) {
2042                return f(self);
2043            } else {
2044                self.window.next_frame.view_stack.push(view_id);
2045                let result = f(self);
2046                self.window.next_frame.view_stack.pop();
2047                result
2048            }
2049        })
2050    }
2051
2052    /// Invoke the given function with the given view id present on the view stack.
2053    /// This is a fairly low-level method used to paint views.
2054    pub fn paint_view<R>(&mut self, view_id: EntityId, f: impl FnOnce(&mut Self) -> R) -> R {
2055        let text_system = self.text_system().clone();
2056        text_system.with_view(view_id, || {
2057            if self.window.next_frame.view_stack.last() == Some(&view_id) {
2058                return f(self);
2059            } else {
2060                self.window.next_frame.view_stack.push(view_id);
2061                self.window
2062                    .next_frame
2063                    .dispatch_tree
2064                    .push_node(None, None, Some(view_id));
2065                let result = f(self);
2066                self.window.next_frame.dispatch_tree.pop_node();
2067                self.window.next_frame.view_stack.pop();
2068                result
2069            }
2070        })
2071    }
2072
2073    /// Update or initialize state for an element with the given id that lives across multiple
2074    /// frames. If an element with this id existed in the rendered frame, its state will be passed
2075    /// to the given closure. The state returned by the closure will be stored so it can be referenced
2076    /// when drawing the next frame.
2077    pub(crate) fn with_element_state<S, R>(
2078        &mut self,
2079        id: ElementId,
2080        f: impl FnOnce(Option<S>, &mut Self) -> (R, S),
2081    ) -> R
2082    where
2083        S: 'static,
2084    {
2085        self.with_element_id(Some(id), |cx| {
2086            let global_id = cx.window().element_id_stack.clone();
2087
2088            if let Some(any) = cx
2089                .window_mut()
2090                .next_frame
2091                .element_states
2092                .remove(&global_id)
2093                .or_else(|| {
2094                    cx.window_mut()
2095                        .rendered_frame
2096                        .element_states
2097                        .remove(&global_id)
2098                })
2099            {
2100                let ElementStateBox {
2101                    inner,
2102                    parent_view_id,
2103                    #[cfg(debug_assertions)]
2104                    type_name
2105                } = any;
2106                // Using the extra inner option to avoid needing to reallocate a new box.
2107                let mut state_box = inner
2108                    .downcast::<Option<S>>()
2109                    .map_err(|_| {
2110                        #[cfg(debug_assertions)]
2111                        {
2112                            anyhow!(
2113                                "invalid element state type for id, requested_type {:?}, actual type: {:?}",
2114                                std::any::type_name::<S>(),
2115                                type_name
2116                            )
2117                        }
2118
2119                        #[cfg(not(debug_assertions))]
2120                        {
2121                            anyhow!(
2122                                "invalid element state type for id, requested_type {:?}",
2123                                std::any::type_name::<S>(),
2124                            )
2125                        }
2126                    })
2127                    .unwrap();
2128
2129                // Actual: Option<AnyElement> <- View
2130                // Requested: () <- AnyElemet
2131                let state = state_box
2132                    .take()
2133                    .expect("element state is already on the stack");
2134                let (result, state) = f(Some(state), cx);
2135                state_box.replace(state);
2136                cx.window_mut()
2137                    .next_frame
2138                    .element_states
2139                    .insert(global_id, ElementStateBox {
2140                        inner: state_box,
2141                        parent_view_id,
2142                        #[cfg(debug_assertions)]
2143                        type_name
2144                    });
2145                result
2146            } else {
2147                let (result, state) = f(None, cx);
2148                let parent_view_id = cx.parent_view_id();
2149                cx.window_mut()
2150                    .next_frame
2151                    .element_states
2152                    .insert(global_id,
2153                        ElementStateBox {
2154                            inner: Box::new(Some(state)),
2155                            parent_view_id,
2156                            #[cfg(debug_assertions)]
2157                            type_name: std::any::type_name::<S>()
2158                        }
2159
2160                    );
2161                result
2162            }
2163        })
2164    }
2165
2166    fn parent_view_id(&self) -> EntityId {
2167        *self
2168            .window
2169            .next_frame
2170            .view_stack
2171            .last()
2172            .expect("a view should always be on the stack while drawing")
2173    }
2174
2175    /// Set an input handler, such as [`ElementInputHandler`][element_input_handler], which interfaces with the
2176    /// platform to receive textual input with proper integration with concerns such
2177    /// as IME interactions. This handler will be active for the upcoming frame until the following frame is
2178    /// rendered.
2179    ///
2180    /// [element_input_handler]: crate::ElementInputHandler
2181    pub fn handle_input(
2182        &mut self,
2183        focus_handle: &FocusHandle,
2184        input_handler: impl PlatformInputHandler,
2185    ) {
2186        if focus_handle.is_focused(self) {
2187            let view_id = self.parent_view_id();
2188            self.window.next_frame.requested_input_handler = Some(RequestedInputHandler {
2189                view_id,
2190                handler: Some(Box::new(input_handler)),
2191            })
2192        }
2193    }
2194
2195    /// Register a callback that can interrupt the closing of the current window based the returned boolean.
2196    /// If the callback returns false, the window won't be closed.
2197    pub fn on_window_should_close(&mut self, f: impl Fn(&mut WindowContext) -> bool + 'static) {
2198        let mut this = self.to_async();
2199        self.window
2200            .platform_window
2201            .on_should_close(Box::new(move || {
2202                this.update(|_, cx| {
2203                    // Ensure that the window is removed from the app if it's been closed
2204                    // by always pre-empting the system close event.
2205                    if f(cx) {
2206                        cx.remove_window();
2207                    }
2208                    false
2209                })
2210                .unwrap_or(true)
2211            }))
2212    }
2213}
2214
2215impl Context for WindowContext<'_> {
2216    type Result<T> = T;
2217
2218    fn new_model<T>(&mut self, build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T) -> Model<T>
2219    where
2220        T: 'static,
2221    {
2222        let slot = self.app.entities.reserve();
2223        let model = build_model(&mut ModelContext::new(&mut *self.app, slot.downgrade()));
2224        self.entities.insert(slot, model)
2225    }
2226
2227    fn update_model<T: 'static, R>(
2228        &mut self,
2229        model: &Model<T>,
2230        update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
2231    ) -> R {
2232        let mut entity = self.entities.lease(model);
2233        let result = update(
2234            &mut *entity,
2235            &mut ModelContext::new(&mut *self.app, model.downgrade()),
2236        );
2237        self.entities.end_lease(entity);
2238        result
2239    }
2240
2241    fn update_window<T, F>(&mut self, window: AnyWindowHandle, update: F) -> Result<T>
2242    where
2243        F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
2244    {
2245        if window == self.window.handle {
2246            let root_view = self.window.root_view.clone().unwrap();
2247            Ok(update(root_view, self))
2248        } else {
2249            window.update(self.app, update)
2250        }
2251    }
2252
2253    fn read_model<T, R>(
2254        &self,
2255        handle: &Model<T>,
2256        read: impl FnOnce(&T, &AppContext) -> R,
2257    ) -> Self::Result<R>
2258    where
2259        T: 'static,
2260    {
2261        let entity = self.entities.read(handle);
2262        read(entity, &*self.app)
2263    }
2264
2265    fn read_window<T, R>(
2266        &self,
2267        window: &WindowHandle<T>,
2268        read: impl FnOnce(View<T>, &AppContext) -> R,
2269    ) -> Result<R>
2270    where
2271        T: 'static,
2272    {
2273        if window.any_handle == self.window.handle {
2274            let root_view = self
2275                .window
2276                .root_view
2277                .clone()
2278                .unwrap()
2279                .downcast::<T>()
2280                .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
2281            Ok(read(root_view, self))
2282        } else {
2283            self.app.read_window(window, read)
2284        }
2285    }
2286}
2287
2288impl VisualContext for WindowContext<'_> {
2289    fn new_view<V>(
2290        &mut self,
2291        build_view_state: impl FnOnce(&mut ViewContext<'_, V>) -> V,
2292    ) -> Self::Result<View<V>>
2293    where
2294        V: 'static + Render,
2295    {
2296        let slot = self.app.entities.reserve();
2297        let view = View {
2298            model: slot.clone(),
2299        };
2300        let mut cx = ViewContext::new(&mut *self.app, &mut *self.window, &view);
2301        let entity = build_view_state(&mut cx);
2302        cx.entities.insert(slot, entity);
2303
2304        cx.new_view_observers
2305            .clone()
2306            .retain(&TypeId::of::<V>(), |observer| {
2307                let any_view = AnyView::from(view.clone());
2308                (observer)(any_view, self);
2309                true
2310            });
2311
2312        view
2313    }
2314
2315    /// Update the given view. Prefer calling `View::update` instead, which calls this method.
2316    fn update_view<T: 'static, R>(
2317        &mut self,
2318        view: &View<T>,
2319        update: impl FnOnce(&mut T, &mut ViewContext<'_, T>) -> R,
2320    ) -> Self::Result<R> {
2321        let mut lease = self.app.entities.lease(&view.model);
2322        let mut cx = ViewContext::new(&mut *self.app, &mut *self.window, view);
2323        let result = update(&mut *lease, &mut cx);
2324        cx.app.entities.end_lease(lease);
2325        result
2326    }
2327
2328    fn replace_root_view<V>(
2329        &mut self,
2330        build_view: impl FnOnce(&mut ViewContext<'_, V>) -> V,
2331    ) -> Self::Result<View<V>>
2332    where
2333        V: 'static + Render,
2334    {
2335        let view = self.new_view(build_view);
2336        self.window.root_view = Some(view.clone().into());
2337        self.refresh();
2338        view
2339    }
2340
2341    fn focus_view<V: crate::FocusableView>(&mut self, view: &View<V>) -> Self::Result<()> {
2342        self.update_view(view, |view, cx| {
2343            view.focus_handle(cx).clone().focus(cx);
2344        })
2345    }
2346
2347    fn dismiss_view<V>(&mut self, view: &View<V>) -> Self::Result<()>
2348    where
2349        V: ManagedView,
2350    {
2351        self.update_view(view, |_, cx| cx.emit(DismissEvent))
2352    }
2353}
2354
2355impl<'a> std::ops::Deref for WindowContext<'a> {
2356    type Target = AppContext;
2357
2358    fn deref(&self) -> &Self::Target {
2359        self.app
2360    }
2361}
2362
2363impl<'a> std::ops::DerefMut for WindowContext<'a> {
2364    fn deref_mut(&mut self) -> &mut Self::Target {
2365        self.app
2366    }
2367}
2368
2369impl<'a> Borrow<AppContext> for WindowContext<'a> {
2370    fn borrow(&self) -> &AppContext {
2371        self.app
2372    }
2373}
2374
2375impl<'a> BorrowMut<AppContext> for WindowContext<'a> {
2376    fn borrow_mut(&mut self) -> &mut AppContext {
2377        self.app
2378    }
2379}
2380
2381/// This trait contains functionality that is shared across [`ViewContext`] and [`WindowContext`]
2382pub trait BorrowWindow: BorrowMut<Window> + BorrowMut<AppContext> {
2383    #[doc(hidden)]
2384    fn app_mut(&mut self) -> &mut AppContext {
2385        self.borrow_mut()
2386    }
2387
2388    #[doc(hidden)]
2389    fn app(&self) -> &AppContext {
2390        self.borrow()
2391    }
2392
2393    #[doc(hidden)]
2394    fn window(&self) -> &Window {
2395        self.borrow()
2396    }
2397
2398    #[doc(hidden)]
2399    fn window_mut(&mut self) -> &mut Window {
2400        self.borrow_mut()
2401    }
2402
2403    /// Pushes the given element id onto the global stack and invokes the given closure
2404    /// with a `GlobalElementId`, which disambiguates the given id in the context of its ancestor
2405    /// ids. Because elements are discarded and recreated on each frame, the `GlobalElementId` is
2406    /// used to associate state with identified elements across separate frames.
2407    fn with_element_id<R>(
2408        &mut self,
2409        id: Option<impl Into<ElementId>>,
2410        f: impl FnOnce(&mut Self) -> R,
2411    ) -> R {
2412        if let Some(id) = id.map(Into::into) {
2413            let window = self.window_mut();
2414            window.element_id_stack.push(id);
2415            let result = f(self);
2416            let window: &mut Window = self.borrow_mut();
2417            window.element_id_stack.pop();
2418            result
2419        } else {
2420            f(self)
2421        }
2422    }
2423
2424    /// Invoke the given function with the given content mask after intersecting it
2425    /// with the current mask.
2426    fn with_content_mask<R>(
2427        &mut self,
2428        mask: Option<ContentMask<Pixels>>,
2429        f: impl FnOnce(&mut Self) -> R,
2430    ) -> R {
2431        if let Some(mask) = mask {
2432            let mask = mask.intersect(&self.content_mask());
2433            self.window_mut().next_frame.content_mask_stack.push(mask);
2434            let result = f(self);
2435            self.window_mut().next_frame.content_mask_stack.pop();
2436            result
2437        } else {
2438            f(self)
2439        }
2440    }
2441
2442    /// Invoke the given function with the content mask reset to that
2443    /// of the window.
2444    fn break_content_mask<R>(&mut self, f: impl FnOnce(&mut Self) -> R) -> R {
2445        let mask = ContentMask {
2446            bounds: Bounds {
2447                origin: Point::default(),
2448                size: self.window().viewport_size,
2449            },
2450        };
2451        let new_stacking_order_id =
2452            post_inc(&mut self.window_mut().next_frame.next_stacking_order_id);
2453        let old_stacking_order = mem::take(&mut self.window_mut().next_frame.z_index_stack);
2454        self.window_mut().next_frame.z_index_stack.id = new_stacking_order_id;
2455        self.window_mut().next_frame.content_mask_stack.push(mask);
2456        let result = f(self);
2457        self.window_mut().next_frame.content_mask_stack.pop();
2458        self.window_mut().next_frame.z_index_stack = old_stacking_order;
2459        result
2460    }
2461
2462    /// Called during painting to invoke the given closure in a new stacking context. The given
2463    /// z-index is interpreted relative to the previous call to `stack`.
2464    fn with_z_index<R>(&mut self, z_index: u8, f: impl FnOnce(&mut Self) -> R) -> R {
2465        let new_stacking_order_id =
2466            post_inc(&mut self.window_mut().next_frame.next_stacking_order_id);
2467        let old_stacking_order_id = mem::replace(
2468            &mut self.window_mut().next_frame.z_index_stack.id,
2469            new_stacking_order_id,
2470        );
2471        self.window_mut().next_frame.z_index_stack.id = new_stacking_order_id;
2472        self.window_mut().next_frame.z_index_stack.push(z_index);
2473        let result = f(self);
2474        self.window_mut().next_frame.z_index_stack.id = old_stacking_order_id;
2475        self.window_mut().next_frame.z_index_stack.pop();
2476        result
2477    }
2478
2479    /// Update the global element offset relative to the current offset. This is used to implement
2480    /// scrolling.
2481    fn with_element_offset<R>(
2482        &mut self,
2483        offset: Point<Pixels>,
2484        f: impl FnOnce(&mut Self) -> R,
2485    ) -> R {
2486        if offset.is_zero() {
2487            return f(self);
2488        };
2489
2490        let abs_offset = self.element_offset() + offset;
2491        self.with_absolute_element_offset(abs_offset, f)
2492    }
2493
2494    /// Update the global element offset based on the given offset. This is used to implement
2495    /// drag handles and other manual painting of elements.
2496    fn with_absolute_element_offset<R>(
2497        &mut self,
2498        offset: Point<Pixels>,
2499        f: impl FnOnce(&mut Self) -> R,
2500    ) -> R {
2501        self.window_mut()
2502            .next_frame
2503            .element_offset_stack
2504            .push(offset);
2505        let result = f(self);
2506        self.window_mut().next_frame.element_offset_stack.pop();
2507        result
2508    }
2509
2510    /// Obtain the current element offset.
2511    fn element_offset(&self) -> Point<Pixels> {
2512        self.window()
2513            .next_frame
2514            .element_offset_stack
2515            .last()
2516            .copied()
2517            .unwrap_or_default()
2518    }
2519
2520    /// Obtain the current content mask.
2521    fn content_mask(&self) -> ContentMask<Pixels> {
2522        self.window()
2523            .next_frame
2524            .content_mask_stack
2525            .last()
2526            .cloned()
2527            .unwrap_or_else(|| ContentMask {
2528                bounds: Bounds {
2529                    origin: Point::default(),
2530                    size: self.window().viewport_size,
2531                },
2532            })
2533    }
2534
2535    /// The size of an em for the base font of the application. Adjusting this value allows the
2536    /// UI to scale, just like zooming a web page.
2537    fn rem_size(&self) -> Pixels {
2538        self.window().rem_size
2539    }
2540}
2541
2542impl Borrow<Window> for WindowContext<'_> {
2543    fn borrow(&self) -> &Window {
2544        self.window
2545    }
2546}
2547
2548impl BorrowMut<Window> for WindowContext<'_> {
2549    fn borrow_mut(&mut self) -> &mut Window {
2550        self.window
2551    }
2552}
2553
2554impl<T> BorrowWindow for T where T: BorrowMut<AppContext> + BorrowMut<Window> {}
2555
2556/// Provides access to application state that is specialized for a particular [`View`].
2557/// Allows you to interact with focus, emit events, etc.
2558/// ViewContext also derefs to [`WindowContext`], giving you access to all of its methods as well.
2559/// When you call [`View::update`], you're passed a `&mut V` and an `&mut ViewContext<V>`.
2560pub struct ViewContext<'a, V> {
2561    window_cx: WindowContext<'a>,
2562    view: &'a View<V>,
2563}
2564
2565impl<V> Borrow<AppContext> for ViewContext<'_, V> {
2566    fn borrow(&self) -> &AppContext {
2567        &*self.window_cx.app
2568    }
2569}
2570
2571impl<V> BorrowMut<AppContext> for ViewContext<'_, V> {
2572    fn borrow_mut(&mut self) -> &mut AppContext {
2573        &mut *self.window_cx.app
2574    }
2575}
2576
2577impl<V> Borrow<Window> for ViewContext<'_, V> {
2578    fn borrow(&self) -> &Window {
2579        &*self.window_cx.window
2580    }
2581}
2582
2583impl<V> BorrowMut<Window> for ViewContext<'_, V> {
2584    fn borrow_mut(&mut self) -> &mut Window {
2585        &mut *self.window_cx.window
2586    }
2587}
2588
2589impl<'a, V: 'static> ViewContext<'a, V> {
2590    pub(crate) fn new(app: &'a mut AppContext, window: &'a mut Window, view: &'a View<V>) -> Self {
2591        Self {
2592            window_cx: WindowContext::new(app, window),
2593            view,
2594        }
2595    }
2596
2597    /// Get the entity_id of this view.
2598    pub fn entity_id(&self) -> EntityId {
2599        self.view.entity_id()
2600    }
2601
2602    /// Get the view pointer underlying this context.
2603    pub fn view(&self) -> &View<V> {
2604        self.view
2605    }
2606
2607    /// Get the model underlying this view.
2608    pub fn model(&self) -> &Model<V> {
2609        &self.view.model
2610    }
2611
2612    /// Access the underlying window context.
2613    pub fn window_context(&mut self) -> &mut WindowContext<'a> {
2614        &mut self.window_cx
2615    }
2616
2617    /// Set a given callback to be run on the next frame.
2618    pub fn on_next_frame(&mut self, f: impl FnOnce(&mut V, &mut ViewContext<V>) + 'static)
2619    where
2620        V: 'static,
2621    {
2622        let view = self.view().clone();
2623        self.window_cx.on_next_frame(move |cx| view.update(cx, f));
2624    }
2625
2626    /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
2627    /// that are currently on the stack to be returned to the app.
2628    pub fn defer(&mut self, f: impl FnOnce(&mut V, &mut ViewContext<V>) + 'static) {
2629        let view = self.view().downgrade();
2630        self.window_cx.defer(move |cx| {
2631            view.update(cx, f).ok();
2632        });
2633    }
2634
2635    /// Observe another model or view for changes to its state, as tracked by [`ModelContext::notify`].
2636    pub fn observe<V2, E>(
2637        &mut self,
2638        entity: &E,
2639        mut on_notify: impl FnMut(&mut V, E, &mut ViewContext<'_, V>) + 'static,
2640    ) -> Subscription
2641    where
2642        V2: 'static,
2643        V: 'static,
2644        E: Entity<V2>,
2645    {
2646        let view = self.view().downgrade();
2647        let entity_id = entity.entity_id();
2648        let entity = entity.downgrade();
2649        let window_handle = self.window.handle;
2650        let (subscription, activate) = self.app.observers.insert(
2651            entity_id,
2652            Box::new(move |cx| {
2653                window_handle
2654                    .update(cx, |_, cx| {
2655                        if let Some(handle) = E::upgrade_from(&entity) {
2656                            view.update(cx, |this, cx| on_notify(this, handle, cx))
2657                                .is_ok()
2658                        } else {
2659                            false
2660                        }
2661                    })
2662                    .unwrap_or(false)
2663            }),
2664        );
2665        self.app.defer(move |_| activate());
2666        subscription
2667    }
2668
2669    /// Subscribe to events emitted by another model or view.
2670    /// The entity to which you're subscribing must implement the [`EventEmitter`] trait.
2671    /// The callback will be invoked with a reference to the current view, a handle to the emitting entity (either a [`View`] or [`Model`]), the event, and a view context for the current view.
2672    pub fn subscribe<V2, E, Evt>(
2673        &mut self,
2674        entity: &E,
2675        mut on_event: impl FnMut(&mut V, E, &Evt, &mut ViewContext<'_, V>) + 'static,
2676    ) -> Subscription
2677    where
2678        V2: EventEmitter<Evt>,
2679        E: Entity<V2>,
2680        Evt: 'static,
2681    {
2682        let view = self.view().downgrade();
2683        let entity_id = entity.entity_id();
2684        let handle = entity.downgrade();
2685        let window_handle = self.window.handle;
2686        let (subscription, activate) = self.app.event_listeners.insert(
2687            entity_id,
2688            (
2689                TypeId::of::<Evt>(),
2690                Box::new(move |event, cx| {
2691                    window_handle
2692                        .update(cx, |_, cx| {
2693                            if let Some(handle) = E::upgrade_from(&handle) {
2694                                let event = event.downcast_ref().expect("invalid event type");
2695                                view.update(cx, |this, cx| on_event(this, handle, event, cx))
2696                                    .is_ok()
2697                            } else {
2698                                false
2699                            }
2700                        })
2701                        .unwrap_or(false)
2702                }),
2703            ),
2704        );
2705        self.app.defer(move |_| activate());
2706        subscription
2707    }
2708
2709    /// Register a callback to be invoked when the view is released.
2710    ///
2711    /// The callback receives a handle to the view's window. This handle may be
2712    /// invalid, if the window was closed before the view was released.
2713    pub fn on_release(
2714        &mut self,
2715        on_release: impl FnOnce(&mut V, AnyWindowHandle, &mut AppContext) + 'static,
2716    ) -> Subscription {
2717        let window_handle = self.window.handle;
2718        let (subscription, activate) = self.app.release_listeners.insert(
2719            self.view.model.entity_id,
2720            Box::new(move |this, cx| {
2721                let this = this.downcast_mut().expect("invalid entity type");
2722                on_release(this, window_handle, cx)
2723            }),
2724        );
2725        activate();
2726        subscription
2727    }
2728
2729    /// Register a callback to be invoked when the given Model or View is released.
2730    pub fn observe_release<V2, E>(
2731        &mut self,
2732        entity: &E,
2733        mut on_release: impl FnMut(&mut V, &mut V2, &mut ViewContext<'_, V>) + 'static,
2734    ) -> Subscription
2735    where
2736        V: 'static,
2737        V2: 'static,
2738        E: Entity<V2>,
2739    {
2740        let view = self.view().downgrade();
2741        let entity_id = entity.entity_id();
2742        let window_handle = self.window.handle;
2743        let (subscription, activate) = self.app.release_listeners.insert(
2744            entity_id,
2745            Box::new(move |entity, cx| {
2746                let entity = entity.downcast_mut().expect("invalid entity type");
2747                let _ = window_handle.update(cx, |_, cx| {
2748                    view.update(cx, |this, cx| on_release(this, entity, cx))
2749                });
2750            }),
2751        );
2752        activate();
2753        subscription
2754    }
2755
2756    /// Indicate that this view has changed, which will invoke any observers and also mark the window as dirty.
2757    /// If this view or any of its ancestors are *cached*, notifying it will cause it or its ancestors to be redrawn.
2758    pub fn notify(&mut self) {
2759        for view_id in self
2760            .window
2761            .rendered_frame
2762            .dispatch_tree
2763            .view_path(self.view.entity_id())
2764            .into_iter()
2765            .rev()
2766        {
2767            if !self.window.dirty_views.insert(view_id) {
2768                break;
2769            }
2770        }
2771
2772        if !self.window.drawing {
2773            self.window_cx.window.dirty = true;
2774            self.window_cx.app.push_effect(Effect::Notify {
2775                emitter: self.view.model.entity_id,
2776            });
2777        }
2778    }
2779
2780    /// Register a callback to be invoked when the window is resized.
2781    pub fn observe_window_bounds(
2782        &mut self,
2783        mut callback: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2784    ) -> Subscription {
2785        let view = self.view.downgrade();
2786        let (subscription, activate) = self.window.bounds_observers.insert(
2787            (),
2788            Box::new(move |cx| view.update(cx, |view, cx| callback(view, cx)).is_ok()),
2789        );
2790        activate();
2791        subscription
2792    }
2793
2794    /// Register a callback to be invoked when the window is activated or deactivated.
2795    pub fn observe_window_activation(
2796        &mut self,
2797        mut callback: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2798    ) -> Subscription {
2799        let view = self.view.downgrade();
2800        let (subscription, activate) = self.window.activation_observers.insert(
2801            (),
2802            Box::new(move |cx| view.update(cx, |view, cx| callback(view, cx)).is_ok()),
2803        );
2804        activate();
2805        subscription
2806    }
2807
2808    /// Register a listener to be called when the given focus handle receives focus.
2809    /// Returns a subscription and persists until the subscription is dropped.
2810    pub fn on_focus(
2811        &mut self,
2812        handle: &FocusHandle,
2813        mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2814    ) -> Subscription {
2815        let view = self.view.downgrade();
2816        let focus_id = handle.id;
2817        let (subscription, activate) = self.window.focus_listeners.insert(
2818            (),
2819            Box::new(move |event, cx| {
2820                view.update(cx, |view, cx| {
2821                    if event.previous_focus_path.last() != Some(&focus_id)
2822                        && event.current_focus_path.last() == Some(&focus_id)
2823                    {
2824                        listener(view, cx)
2825                    }
2826                })
2827                .is_ok()
2828            }),
2829        );
2830        self.app.defer(move |_| activate());
2831        subscription
2832    }
2833
2834    /// Register a listener to be called when the given focus handle or one of its descendants receives focus.
2835    /// Returns a subscription and persists until the subscription is dropped.
2836    pub fn on_focus_in(
2837        &mut self,
2838        handle: &FocusHandle,
2839        mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2840    ) -> Subscription {
2841        let view = self.view.downgrade();
2842        let focus_id = handle.id;
2843        let (subscription, activate) = self.window.focus_listeners.insert(
2844            (),
2845            Box::new(move |event, cx| {
2846                view.update(cx, |view, cx| {
2847                    if !event.previous_focus_path.contains(&focus_id)
2848                        && event.current_focus_path.contains(&focus_id)
2849                    {
2850                        listener(view, cx)
2851                    }
2852                })
2853                .is_ok()
2854            }),
2855        );
2856        self.app.defer(move |_| activate());
2857        subscription
2858    }
2859
2860    /// Register a listener to be called when the given focus handle loses focus.
2861    /// Returns a subscription and persists until the subscription is dropped.
2862    pub fn on_blur(
2863        &mut self,
2864        handle: &FocusHandle,
2865        mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2866    ) -> Subscription {
2867        let view = self.view.downgrade();
2868        let focus_id = handle.id;
2869        let (subscription, activate) = self.window.focus_listeners.insert(
2870            (),
2871            Box::new(move |event, cx| {
2872                view.update(cx, |view, cx| {
2873                    if event.previous_focus_path.last() == Some(&focus_id)
2874                        && event.current_focus_path.last() != Some(&focus_id)
2875                    {
2876                        listener(view, cx)
2877                    }
2878                })
2879                .is_ok()
2880            }),
2881        );
2882        self.app.defer(move |_| activate());
2883        subscription
2884    }
2885
2886    /// Register a listener to be called when nothing in the window has focus.
2887    /// This typically happens when the node that was focused is removed from the tree,
2888    /// and this callback lets you chose a default place to restore the users focus.
2889    /// Returns a subscription and persists until the subscription is dropped.
2890    pub fn on_focus_lost(
2891        &mut self,
2892        mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2893    ) -> Subscription {
2894        let view = self.view.downgrade();
2895        let (subscription, activate) = self.window.focus_lost_listeners.insert(
2896            (),
2897            Box::new(move |cx| view.update(cx, |view, cx| listener(view, cx)).is_ok()),
2898        );
2899        activate();
2900        subscription
2901    }
2902
2903    /// Register a listener to be called when the given focus handle or one of its descendants loses focus.
2904    /// Returns a subscription and persists until the subscription is dropped.
2905    pub fn on_focus_out(
2906        &mut self,
2907        handle: &FocusHandle,
2908        mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2909    ) -> Subscription {
2910        let view = self.view.downgrade();
2911        let focus_id = handle.id;
2912        let (subscription, activate) = self.window.focus_listeners.insert(
2913            (),
2914            Box::new(move |event, cx| {
2915                view.update(cx, |view, cx| {
2916                    if event.previous_focus_path.contains(&focus_id)
2917                        && !event.current_focus_path.contains(&focus_id)
2918                    {
2919                        listener(view, cx)
2920                    }
2921                })
2922                .is_ok()
2923            }),
2924        );
2925        self.app.defer(move |_| activate());
2926        subscription
2927    }
2928
2929    /// Schedule a future to be run asynchronously.
2930    /// The given callback is invoked with a [`WeakView<V>`] to avoid leaking the view for a long-running process.
2931    /// It's also given an [`AsyncWindowContext`], which can be used to access the state of the view across await points.
2932    /// The returned future will be polled on the main thread.
2933    pub fn spawn<Fut, R>(
2934        &mut self,
2935        f: impl FnOnce(WeakView<V>, AsyncWindowContext) -> Fut,
2936    ) -> Task<R>
2937    where
2938        R: 'static,
2939        Fut: Future<Output = R> + 'static,
2940    {
2941        let view = self.view().downgrade();
2942        self.window_cx.spawn(|cx| f(view, cx))
2943    }
2944
2945    /// Update the global state of the given type.
2946    pub fn update_global<G, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R
2947    where
2948        G: 'static,
2949    {
2950        let mut global = self.app.lease_global::<G>();
2951        let result = f(&mut global, self);
2952        self.app.end_global_lease(global);
2953        result
2954    }
2955
2956    /// Register a callback to be invoked when the given global state changes.
2957    pub fn observe_global<G: 'static>(
2958        &mut self,
2959        mut f: impl FnMut(&mut V, &mut ViewContext<'_, V>) + 'static,
2960    ) -> Subscription {
2961        let window_handle = self.window.handle;
2962        let view = self.view().downgrade();
2963        let (subscription, activate) = self.global_observers.insert(
2964            TypeId::of::<G>(),
2965            Box::new(move |cx| {
2966                window_handle
2967                    .update(cx, |_, cx| view.update(cx, |view, cx| f(view, cx)).is_ok())
2968                    .unwrap_or(false)
2969            }),
2970        );
2971        self.app.defer(move |_| activate());
2972        subscription
2973    }
2974
2975    /// Add a listener for any mouse event that occurs in the window.
2976    /// This is a fairly low level method.
2977    /// Typically, you'll want to use methods on UI elements, which perform bounds checking etc.
2978    pub fn on_mouse_event<Event: 'static>(
2979        &mut self,
2980        handler: impl Fn(&mut V, &Event, DispatchPhase, &mut ViewContext<V>) + 'static,
2981    ) {
2982        let handle = self.view().clone();
2983        self.window_cx.on_mouse_event(move |event, phase, cx| {
2984            handle.update(cx, |view, cx| {
2985                handler(view, event, phase, cx);
2986            })
2987        });
2988    }
2989
2990    /// Register a callback to be invoked when the given Key Event is dispatched to the window.
2991    pub fn on_key_event<Event: 'static>(
2992        &mut self,
2993        handler: impl Fn(&mut V, &Event, DispatchPhase, &mut ViewContext<V>) + 'static,
2994    ) {
2995        let handle = self.view().clone();
2996        self.window_cx.on_key_event(move |event, phase, cx| {
2997            handle.update(cx, |view, cx| {
2998                handler(view, event, phase, cx);
2999            })
3000        });
3001    }
3002
3003    /// Register a callback to be invoked when the given Action type is dispatched to the window.
3004    pub fn on_action(
3005        &mut self,
3006        action_type: TypeId,
3007        listener: impl Fn(&mut V, &dyn Any, DispatchPhase, &mut ViewContext<V>) + 'static,
3008    ) {
3009        let handle = self.view().clone();
3010        self.window_cx
3011            .on_action(action_type, move |action, phase, cx| {
3012                handle.update(cx, |view, cx| {
3013                    listener(view, action, phase, cx);
3014                })
3015            });
3016    }
3017
3018    /// Emit an event to be handled any other views that have subscribed via [ViewContext::subscribe].
3019    pub fn emit<Evt>(&mut self, event: Evt)
3020    where
3021        Evt: 'static,
3022        V: EventEmitter<Evt>,
3023    {
3024        let emitter = self.view.model.entity_id;
3025        self.app.push_effect(Effect::Emit {
3026            emitter,
3027            event_type: TypeId::of::<Evt>(),
3028            event: Box::new(event),
3029        });
3030    }
3031
3032    /// Move focus to the current view, assuming it implements [`FocusableView`].
3033    pub fn focus_self(&mut self)
3034    where
3035        V: FocusableView,
3036    {
3037        self.defer(|view, cx| view.focus_handle(cx).focus(cx))
3038    }
3039
3040    /// Convenience method for accessing view state in an event callback.
3041    ///
3042    /// Many GPUI callbacks take the form of `Fn(&E, &mut WindowContext)`,
3043    /// but it's often useful to be able to access view state in these
3044    /// callbacks. This method provides a convenient way to do so.
3045    pub fn listener<E>(
3046        &self,
3047        f: impl Fn(&mut V, &E, &mut ViewContext<V>) + 'static,
3048    ) -> impl Fn(&E, &mut WindowContext) + 'static {
3049        let view = self.view().downgrade();
3050        move |e: &E, cx: &mut WindowContext| {
3051            view.update(cx, |view, cx| f(view, e, cx)).ok();
3052        }
3053    }
3054}
3055
3056impl<V> Context for ViewContext<'_, V> {
3057    type Result<U> = U;
3058
3059    fn new_model<T: 'static>(
3060        &mut self,
3061        build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
3062    ) -> Model<T> {
3063        self.window_cx.new_model(build_model)
3064    }
3065
3066    fn update_model<T: 'static, R>(
3067        &mut self,
3068        model: &Model<T>,
3069        update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
3070    ) -> R {
3071        self.window_cx.update_model(model, update)
3072    }
3073
3074    fn update_window<T, F>(&mut self, window: AnyWindowHandle, update: F) -> Result<T>
3075    where
3076        F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
3077    {
3078        self.window_cx.update_window(window, update)
3079    }
3080
3081    fn read_model<T, R>(
3082        &self,
3083        handle: &Model<T>,
3084        read: impl FnOnce(&T, &AppContext) -> R,
3085    ) -> Self::Result<R>
3086    where
3087        T: 'static,
3088    {
3089        self.window_cx.read_model(handle, read)
3090    }
3091
3092    fn read_window<T, R>(
3093        &self,
3094        window: &WindowHandle<T>,
3095        read: impl FnOnce(View<T>, &AppContext) -> R,
3096    ) -> Result<R>
3097    where
3098        T: 'static,
3099    {
3100        self.window_cx.read_window(window, read)
3101    }
3102}
3103
3104impl<V: 'static> VisualContext for ViewContext<'_, V> {
3105    fn new_view<W: Render + 'static>(
3106        &mut self,
3107        build_view_state: impl FnOnce(&mut ViewContext<'_, W>) -> W,
3108    ) -> Self::Result<View<W>> {
3109        self.window_cx.new_view(build_view_state)
3110    }
3111
3112    fn update_view<V2: 'static, R>(
3113        &mut self,
3114        view: &View<V2>,
3115        update: impl FnOnce(&mut V2, &mut ViewContext<'_, V2>) -> R,
3116    ) -> Self::Result<R> {
3117        self.window_cx.update_view(view, update)
3118    }
3119
3120    fn replace_root_view<W>(
3121        &mut self,
3122        build_view: impl FnOnce(&mut ViewContext<'_, W>) -> W,
3123    ) -> Self::Result<View<W>>
3124    where
3125        W: 'static + Render,
3126    {
3127        self.window_cx.replace_root_view(build_view)
3128    }
3129
3130    fn focus_view<W: FocusableView>(&mut self, view: &View<W>) -> Self::Result<()> {
3131        self.window_cx.focus_view(view)
3132    }
3133
3134    fn dismiss_view<W: ManagedView>(&mut self, view: &View<W>) -> Self::Result<()> {
3135        self.window_cx.dismiss_view(view)
3136    }
3137}
3138
3139impl<'a, V> std::ops::Deref for ViewContext<'a, V> {
3140    type Target = WindowContext<'a>;
3141
3142    fn deref(&self) -> &Self::Target {
3143        &self.window_cx
3144    }
3145}
3146
3147impl<'a, V> std::ops::DerefMut for ViewContext<'a, V> {
3148    fn deref_mut(&mut self) -> &mut Self::Target {
3149        &mut self.window_cx
3150    }
3151}
3152
3153// #[derive(Clone, Copy, Eq, PartialEq, Hash)]
3154slotmap::new_key_type! {
3155    /// A unique identifier for a window.
3156    pub struct WindowId;
3157}
3158
3159impl WindowId {
3160    /// Converts this window ID to a `u64`.
3161    pub fn as_u64(&self) -> u64 {
3162        self.0.as_ffi()
3163    }
3164}
3165
3166/// A handle to a window with a specific root view type.
3167/// Note that this does not keep the window alive on its own.
3168#[derive(Deref, DerefMut)]
3169pub struct WindowHandle<V> {
3170    #[deref]
3171    #[deref_mut]
3172    pub(crate) any_handle: AnyWindowHandle,
3173    state_type: PhantomData<V>,
3174}
3175
3176impl<V: 'static + Render> WindowHandle<V> {
3177    /// Create a new handle from a window ID.
3178    /// This does not check if the root type of the window is `V`.
3179    pub fn new(id: WindowId) -> Self {
3180        WindowHandle {
3181            any_handle: AnyWindowHandle {
3182                id,
3183                state_type: TypeId::of::<V>(),
3184            },
3185            state_type: PhantomData,
3186        }
3187    }
3188
3189    /// Get the root view out of this window.
3190    ///
3191    /// This will fail if the window is closed or if the root view's type does not match `V`.
3192    pub fn root<C>(&self, cx: &mut C) -> Result<View<V>>
3193    where
3194        C: Context,
3195    {
3196        Flatten::flatten(cx.update_window(self.any_handle, |root_view, _| {
3197            root_view
3198                .downcast::<V>()
3199                .map_err(|_| anyhow!("the type of the window's root view has changed"))
3200        }))
3201    }
3202
3203    /// Update the root view of this window.
3204    ///
3205    /// This will fail if the window has been closed or if the root view's type does not match
3206    pub fn update<C, R>(
3207        &self,
3208        cx: &mut C,
3209        update: impl FnOnce(&mut V, &mut ViewContext<'_, V>) -> R,
3210    ) -> Result<R>
3211    where
3212        C: Context,
3213    {
3214        cx.update_window(self.any_handle, |root_view, cx| {
3215            let view = root_view
3216                .downcast::<V>()
3217                .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
3218            Ok(cx.update_view(&view, update))
3219        })?
3220    }
3221
3222    /// Read the root view out of this window.
3223    ///
3224    /// This will fail if the window is closed or if the root view's type does not match `V`.
3225    pub fn read<'a>(&self, cx: &'a AppContext) -> Result<&'a V> {
3226        let x = cx
3227            .windows
3228            .get(self.id)
3229            .and_then(|window| {
3230                window
3231                    .as_ref()
3232                    .and_then(|window| window.root_view.clone())
3233                    .map(|root_view| root_view.downcast::<V>())
3234            })
3235            .ok_or_else(|| anyhow!("window not found"))?
3236            .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
3237
3238        Ok(x.read(cx))
3239    }
3240
3241    /// Read the root view out of this window, with a callback
3242    ///
3243    /// This will fail if the window is closed or if the root view's type does not match `V`.
3244    pub fn read_with<C, R>(&self, cx: &C, read_with: impl FnOnce(&V, &AppContext) -> R) -> Result<R>
3245    where
3246        C: Context,
3247    {
3248        cx.read_window(self, |root_view, cx| read_with(root_view.read(cx), cx))
3249    }
3250
3251    /// Read the root view pointer off of this window.
3252    ///
3253    /// This will fail if the window is closed or if the root view's type does not match `V`.
3254    pub fn root_view<C>(&self, cx: &C) -> Result<View<V>>
3255    where
3256        C: Context,
3257    {
3258        cx.read_window(self, |root_view, _cx| root_view.clone())
3259    }
3260
3261    /// Check if this window is 'active'.
3262    ///
3263    /// Will return `None` if the window is closed.
3264    pub fn is_active(&self, cx: &AppContext) -> Option<bool> {
3265        cx.windows
3266            .get(self.id)
3267            .and_then(|window| window.as_ref().map(|window| window.active))
3268    }
3269}
3270
3271impl<V> Copy for WindowHandle<V> {}
3272
3273impl<V> Clone for WindowHandle<V> {
3274    fn clone(&self) -> Self {
3275        *self
3276    }
3277}
3278
3279impl<V> PartialEq for WindowHandle<V> {
3280    fn eq(&self, other: &Self) -> bool {
3281        self.any_handle == other.any_handle
3282    }
3283}
3284
3285impl<V> Eq for WindowHandle<V> {}
3286
3287impl<V> Hash for WindowHandle<V> {
3288    fn hash<H: Hasher>(&self, state: &mut H) {
3289        self.any_handle.hash(state);
3290    }
3291}
3292
3293impl<V: 'static> From<WindowHandle<V>> for AnyWindowHandle {
3294    fn from(val: WindowHandle<V>) -> Self {
3295        val.any_handle
3296    }
3297}
3298
3299/// A handle to a window with any root view type, which can be downcast to a window with a specific root view type.
3300#[derive(Copy, Clone, PartialEq, Eq, Hash)]
3301pub struct AnyWindowHandle {
3302    pub(crate) id: WindowId,
3303    state_type: TypeId,
3304}
3305
3306impl AnyWindowHandle {
3307    /// Get the ID of this window.
3308    pub fn window_id(&self) -> WindowId {
3309        self.id
3310    }
3311
3312    /// Attempt to convert this handle to a window handle with a specific root view type.
3313    /// If the types do not match, this will return `None`.
3314    pub fn downcast<T: 'static>(&self) -> Option<WindowHandle<T>> {
3315        if TypeId::of::<T>() == self.state_type {
3316            Some(WindowHandle {
3317                any_handle: *self,
3318                state_type: PhantomData,
3319            })
3320        } else {
3321            None
3322        }
3323    }
3324
3325    /// Update the state of the root view of this window.
3326    ///
3327    /// This will fail if the window has been closed.
3328    pub fn update<C, R>(
3329        self,
3330        cx: &mut C,
3331        update: impl FnOnce(AnyView, &mut WindowContext<'_>) -> R,
3332    ) -> Result<R>
3333    where
3334        C: Context,
3335    {
3336        cx.update_window(self, update)
3337    }
3338
3339    /// Read the state of the root view of this window.
3340    ///
3341    /// This will fail if the window has been closed.
3342    pub fn read<T, C, R>(self, cx: &C, read: impl FnOnce(View<T>, &AppContext) -> R) -> Result<R>
3343    where
3344        C: Context,
3345        T: 'static,
3346    {
3347        let view = self
3348            .downcast::<T>()
3349            .context("the type of the window's root view has changed")?;
3350
3351        cx.read_window(&view, read)
3352    }
3353}
3354
3355/// An identifier for an [`Element`](crate::Element).
3356///
3357/// Can be constructed with a string, a number, or both, as well
3358/// as other internal representations.
3359#[derive(Clone, Debug, Eq, PartialEq, Hash)]
3360pub enum ElementId {
3361    /// The ID of a View element
3362    View(EntityId),
3363    /// An integer ID.
3364    Integer(usize),
3365    /// A string based ID.
3366    Name(SharedString),
3367    /// An ID that's equated with a focus handle.
3368    FocusHandle(FocusId),
3369    /// A combination of a name and an integer.
3370    NamedInteger(SharedString, usize),
3371}
3372
3373impl ElementId {
3374    pub(crate) fn from_entity_id(entity_id: EntityId) -> Self {
3375        ElementId::View(entity_id)
3376    }
3377}
3378
3379impl TryInto<SharedString> for ElementId {
3380    type Error = anyhow::Error;
3381
3382    fn try_into(self) -> anyhow::Result<SharedString> {
3383        if let ElementId::Name(name) = self {
3384            Ok(name)
3385        } else {
3386            Err(anyhow!("element id is not string"))
3387        }
3388    }
3389}
3390
3391impl From<usize> for ElementId {
3392    fn from(id: usize) -> Self {
3393        ElementId::Integer(id)
3394    }
3395}
3396
3397impl From<i32> for ElementId {
3398    fn from(id: i32) -> Self {
3399        Self::Integer(id as usize)
3400    }
3401}
3402
3403impl From<SharedString> for ElementId {
3404    fn from(name: SharedString) -> Self {
3405        ElementId::Name(name)
3406    }
3407}
3408
3409impl From<&'static str> for ElementId {
3410    fn from(name: &'static str) -> Self {
3411        ElementId::Name(name.into())
3412    }
3413}
3414
3415impl<'a> From<&'a FocusHandle> for ElementId {
3416    fn from(handle: &'a FocusHandle) -> Self {
3417        ElementId::FocusHandle(handle.id)
3418    }
3419}
3420
3421impl From<(&'static str, EntityId)> for ElementId {
3422    fn from((name, id): (&'static str, EntityId)) -> Self {
3423        ElementId::NamedInteger(name.into(), id.as_u64() as usize)
3424    }
3425}
3426
3427impl From<(&'static str, usize)> for ElementId {
3428    fn from((name, id): (&'static str, usize)) -> Self {
3429        ElementId::NamedInteger(name.into(), id)
3430    }
3431}
3432
3433impl From<(&'static str, u64)> for ElementId {
3434    fn from((name, id): (&'static str, u64)) -> Self {
3435        ElementId::NamedInteger(name.into(), id as usize)
3436    }
3437}
3438
3439/// A rectangle to be rendered in the window at the given position and size.
3440/// Passed as an argument [`WindowContext::paint_quad`].
3441#[derive(Clone)]
3442pub struct PaintQuad {
3443    bounds: Bounds<Pixels>,
3444    corner_radii: Corners<Pixels>,
3445    background: Hsla,
3446    border_widths: Edges<Pixels>,
3447    border_color: Hsla,
3448}
3449
3450impl PaintQuad {
3451    /// Set the corner radii of the quad.
3452    pub fn corner_radii(self, corner_radii: impl Into<Corners<Pixels>>) -> Self {
3453        PaintQuad {
3454            corner_radii: corner_radii.into(),
3455            ..self
3456        }
3457    }
3458
3459    /// Set the border widths of the quad.
3460    pub fn border_widths(self, border_widths: impl Into<Edges<Pixels>>) -> Self {
3461        PaintQuad {
3462            border_widths: border_widths.into(),
3463            ..self
3464        }
3465    }
3466
3467    /// Set the border color of the quad.
3468    pub fn border_color(self, border_color: impl Into<Hsla>) -> Self {
3469        PaintQuad {
3470            border_color: border_color.into(),
3471            ..self
3472        }
3473    }
3474
3475    /// Set the background color of the quad.
3476    pub fn background(self, background: impl Into<Hsla>) -> Self {
3477        PaintQuad {
3478            background: background.into(),
3479            ..self
3480        }
3481    }
3482}
3483
3484/// Create a quad with the given parameters.
3485pub fn quad(
3486    bounds: Bounds<Pixels>,
3487    corner_radii: impl Into<Corners<Pixels>>,
3488    background: impl Into<Hsla>,
3489    border_widths: impl Into<Edges<Pixels>>,
3490    border_color: impl Into<Hsla>,
3491) -> PaintQuad {
3492    PaintQuad {
3493        bounds,
3494        corner_radii: corner_radii.into(),
3495        background: background.into(),
3496        border_widths: border_widths.into(),
3497        border_color: border_color.into(),
3498    }
3499}
3500
3501/// Create a filled quad with the given bounds and background color.
3502pub fn fill(bounds: impl Into<Bounds<Pixels>>, background: impl Into<Hsla>) -> PaintQuad {
3503    PaintQuad {
3504        bounds: bounds.into(),
3505        corner_radii: (0.).into(),
3506        background: background.into(),
3507        border_widths: (0.).into(),
3508        border_color: transparent_black(),
3509    }
3510}
3511
3512/// Create a rectangle outline with the given bounds, border color, and a 1px border width
3513pub fn outline(bounds: impl Into<Bounds<Pixels>>, border_color: impl Into<Hsla>) -> PaintQuad {
3514    PaintQuad {
3515        bounds: bounds.into(),
3516        corner_radii: (0.).into(),
3517        background: transparent_black(),
3518        border_widths: (1.).into(),
3519        border_color: border_color.into(),
3520    }
3521}