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    next_root_z_index: u8,
 319    content_mask_stack: Vec<ContentMask<Pixels>>,
 320    element_offset_stack: Vec<Point<Pixels>>,
 321    requested_input_handler: Option<RequestedInputHandler>,
 322    tooltip_request: Option<TooltipRequest>,
 323    cursor_styles: FxHashMap<EntityId, CursorStyle>,
 324    requested_cursor_style: Option<CursorStyle>,
 325    pub(crate) view_stack: Vec<EntityId>,
 326    pub(crate) reused_views: FxHashSet<EntityId>,
 327}
 328
 329impl Frame {
 330    fn new(dispatch_tree: DispatchTree) -> Self {
 331        Frame {
 332            focus: None,
 333            window_active: false,
 334            element_states: FxHashMap::default(),
 335            mouse_listeners: FxHashMap::default(),
 336            dispatch_tree,
 337            scene: Scene::default(),
 338            depth_map: Vec::new(),
 339            z_index_stack: StackingOrder::default(),
 340            next_stacking_order_id: 0,
 341            next_root_z_index: 0,
 342            content_mask_stack: Vec::new(),
 343            element_offset_stack: Vec::new(),
 344            requested_input_handler: None,
 345            tooltip_request: None,
 346            cursor_styles: FxHashMap::default(),
 347            requested_cursor_style: None,
 348            view_stack: Vec::new(),
 349            reused_views: FxHashSet::default(),
 350        }
 351    }
 352
 353    fn clear(&mut self) {
 354        self.element_states.clear();
 355        self.mouse_listeners.values_mut().for_each(Vec::clear);
 356        self.dispatch_tree.clear();
 357        self.depth_map.clear();
 358        self.next_stacking_order_id = 0;
 359        self.next_root_z_index = 0;
 360        self.reused_views.clear();
 361        self.scene.clear();
 362        self.requested_input_handler.take();
 363        self.tooltip_request.take();
 364        self.cursor_styles.clear();
 365        self.requested_cursor_style.take();
 366        debug_assert_eq!(self.view_stack.len(), 0);
 367    }
 368
 369    fn focus_path(&self) -> SmallVec<[FocusId; 8]> {
 370        self.focus
 371            .map(|focus_id| self.dispatch_tree.focus_path(focus_id))
 372            .unwrap_or_default()
 373    }
 374
 375    fn finish(&mut self, prev_frame: &mut Self) {
 376        // Reuse mouse listeners that didn't change since the last frame.
 377        for (type_id, listeners) in &mut prev_frame.mouse_listeners {
 378            let next_listeners = self.mouse_listeners.entry(*type_id).or_default();
 379            for (order, view_id, listener) in listeners.drain(..) {
 380                if self.reused_views.contains(&view_id) {
 381                    next_listeners.push((order, view_id, listener));
 382                }
 383            }
 384        }
 385
 386        // Reuse entries in the depth map that didn't change since the last frame.
 387        for (order, view_id, bounds) in prev_frame.depth_map.drain(..) {
 388            if self.reused_views.contains(&view_id) {
 389                match self
 390                    .depth_map
 391                    .binary_search_by(|(level, _, _)| order.cmp(level))
 392                {
 393                    Ok(i) | Err(i) => self.depth_map.insert(i, (order, view_id, bounds)),
 394                }
 395            }
 396        }
 397
 398        // Retain element states for views that didn't change since the last frame.
 399        for (element_id, state) in prev_frame.element_states.drain() {
 400            if self.reused_views.contains(&state.parent_view_id) {
 401                self.element_states.entry(element_id).or_insert(state);
 402            }
 403        }
 404
 405        // Reuse geometry that didn't change since the last frame.
 406        self.scene
 407            .reuse_views(&self.reused_views, &mut prev_frame.scene);
 408        self.scene.finish();
 409    }
 410}
 411
 412impl Window {
 413    pub(crate) fn new(
 414        handle: AnyWindowHandle,
 415        options: WindowOptions,
 416        cx: &mut AppContext,
 417    ) -> Self {
 418        let platform_window = cx.platform.open_window(handle, options);
 419        let display_id = platform_window.display().id();
 420        let sprite_atlas = platform_window.sprite_atlas();
 421        let mouse_position = platform_window.mouse_position();
 422        let modifiers = platform_window.modifiers();
 423        let content_size = platform_window.content_size();
 424        let scale_factor = platform_window.scale_factor();
 425        let bounds = platform_window.bounds();
 426
 427        platform_window.on_request_frame(Box::new({
 428            let mut cx = cx.to_async();
 429            move || {
 430                handle.update(&mut cx, |_, cx| cx.draw()).log_err();
 431            }
 432        }));
 433        platform_window.on_resize(Box::new({
 434            let mut cx = cx.to_async();
 435            move |_, _| {
 436                handle
 437                    .update(&mut cx, |_, cx| cx.window_bounds_changed())
 438                    .log_err();
 439            }
 440        }));
 441        platform_window.on_moved(Box::new({
 442            let mut cx = cx.to_async();
 443            move || {
 444                handle
 445                    .update(&mut cx, |_, cx| cx.window_bounds_changed())
 446                    .log_err();
 447            }
 448        }));
 449        platform_window.on_active_status_change(Box::new({
 450            let mut cx = cx.to_async();
 451            move |active| {
 452                handle
 453                    .update(&mut cx, |_, cx| {
 454                        cx.window.active = active;
 455                        cx.window
 456                            .activation_observers
 457                            .clone()
 458                            .retain(&(), |callback| callback(cx));
 459                    })
 460                    .log_err();
 461            }
 462        }));
 463
 464        platform_window.on_input({
 465            let mut cx = cx.to_async();
 466            Box::new(move |event| {
 467                handle
 468                    .update(&mut cx, |_, cx| cx.dispatch_event(event))
 469                    .log_err()
 470                    .unwrap_or(false)
 471            })
 472        });
 473
 474        Window {
 475            handle,
 476            removed: false,
 477            platform_window,
 478            display_id,
 479            sprite_atlas,
 480            rem_size: px(16.),
 481            viewport_size: content_size,
 482            layout_engine: Some(TaffyLayoutEngine::new()),
 483            root_view: None,
 484            element_id_stack: GlobalElementId::default(),
 485            rendered_frame: Frame::new(DispatchTree::new(cx.keymap.clone(), cx.actions.clone())),
 486            next_frame: Frame::new(DispatchTree::new(cx.keymap.clone(), cx.actions.clone())),
 487            dirty_views: FxHashSet::default(),
 488            focus_handles: Arc::new(RwLock::new(SlotMap::with_key())),
 489            focus_listeners: SubscriberSet::new(),
 490            focus_lost_listeners: SubscriberSet::new(),
 491            default_prevented: true,
 492            mouse_position,
 493            modifiers,
 494            scale_factor,
 495            bounds,
 496            bounds_observers: SubscriberSet::new(),
 497            active: false,
 498            dirty: false,
 499            refreshing: false,
 500            drawing: false,
 501            activation_observers: SubscriberSet::new(),
 502            focus: None,
 503            focus_enabled: true,
 504
 505            #[cfg(any(test, feature = "test-support"))]
 506            focus_invalidated: false,
 507        }
 508    }
 509}
 510
 511/// Indicates which region of the window is visible. Content falling outside of this mask will not be
 512/// rendered. Currently, only rectangular content masks are supported, but we give the mask its own type
 513/// to leave room to support more complex shapes in the future.
 514#[derive(Clone, Debug, Default, PartialEq, Eq)]
 515#[repr(C)]
 516pub struct ContentMask<P: Clone + Default + Debug> {
 517    /// The bounds
 518    pub bounds: Bounds<P>,
 519}
 520
 521impl ContentMask<Pixels> {
 522    /// Scale the content mask's pixel units by the given scaling factor.
 523    pub fn scale(&self, factor: f32) -> ContentMask<ScaledPixels> {
 524        ContentMask {
 525            bounds: self.bounds.scale(factor),
 526        }
 527    }
 528
 529    /// Intersect the content mask with the given content mask.
 530    pub fn intersect(&self, other: &Self) -> Self {
 531        let bounds = self.bounds.intersect(&other.bounds);
 532        ContentMask { bounds }
 533    }
 534}
 535
 536/// Provides access to application state in the context of a single window. Derefs
 537/// to an [`AppContext`], so you can also pass a [`WindowContext`] to any method that takes
 538/// an [`AppContext`] and call any [`AppContext`] methods.
 539pub struct WindowContext<'a> {
 540    pub(crate) app: &'a mut AppContext,
 541    pub(crate) window: &'a mut Window,
 542}
 543
 544impl<'a> WindowContext<'a> {
 545    pub(crate) fn new(app: &'a mut AppContext, window: &'a mut Window) -> Self {
 546        Self { app, window }
 547    }
 548
 549    /// Obtain a handle to the window that belongs to this context.
 550    pub fn window_handle(&self) -> AnyWindowHandle {
 551        self.window.handle
 552    }
 553
 554    /// Mark the window as dirty, scheduling it to be redrawn on the next frame.
 555    pub fn refresh(&mut self) {
 556        if !self.window.drawing {
 557            self.window.refreshing = true;
 558            self.window.dirty = true;
 559        }
 560    }
 561
 562    /// Close this window.
 563    pub fn remove_window(&mut self) {
 564        self.window.removed = true;
 565    }
 566
 567    /// Obtain a new [`FocusHandle`], which allows you to track and manipulate the keyboard focus
 568    /// for elements rendered within this window.
 569    pub fn focus_handle(&mut self) -> FocusHandle {
 570        FocusHandle::new(&self.window.focus_handles)
 571    }
 572
 573    /// Obtain the currently focused [`FocusHandle`]. If no elements are focused, returns `None`.
 574    pub fn focused(&self) -> Option<FocusHandle> {
 575        self.window
 576            .focus
 577            .and_then(|id| FocusHandle::for_id(id, &self.window.focus_handles))
 578    }
 579
 580    /// Move focus to the element associated with the given [`FocusHandle`].
 581    pub fn focus(&mut self, handle: &FocusHandle) {
 582        if !self.window.focus_enabled || self.window.focus == Some(handle.id) {
 583            return;
 584        }
 585
 586        self.window.focus = Some(handle.id);
 587        self.window
 588            .rendered_frame
 589            .dispatch_tree
 590            .clear_pending_keystrokes();
 591
 592        #[cfg(any(test, feature = "test-support"))]
 593        {
 594            self.window.focus_invalidated = true;
 595        }
 596
 597        self.refresh();
 598    }
 599
 600    /// Remove focus from all elements within this context's window.
 601    pub fn blur(&mut self) {
 602        if !self.window.focus_enabled {
 603            return;
 604        }
 605
 606        self.window.focus = None;
 607        self.refresh();
 608    }
 609
 610    /// Blur the window and don't allow anything in it to be focused again.
 611    pub fn disable_focus(&mut self) {
 612        self.blur();
 613        self.window.focus_enabled = false;
 614    }
 615
 616    /// Dispatch the given action on the currently focused element.
 617    pub fn dispatch_action(&mut self, action: Box<dyn Action>) {
 618        let focus_handle = self.focused();
 619
 620        self.defer(move |cx| {
 621            let node_id = focus_handle
 622                .and_then(|handle| {
 623                    cx.window
 624                        .rendered_frame
 625                        .dispatch_tree
 626                        .focusable_node_id(handle.id)
 627                })
 628                .unwrap_or_else(|| cx.window.rendered_frame.dispatch_tree.root_node_id());
 629
 630            cx.propagate_event = true;
 631            cx.dispatch_action_on_node(node_id, action);
 632        })
 633    }
 634
 635    pub(crate) fn dispatch_keystroke_observers(
 636        &mut self,
 637        event: &dyn Any,
 638        action: Option<Box<dyn Action>>,
 639    ) {
 640        let Some(key_down_event) = event.downcast_ref::<KeyDownEvent>() else {
 641            return;
 642        };
 643
 644        self.keystroke_observers
 645            .clone()
 646            .retain(&(), move |callback| {
 647                (callback)(
 648                    &KeystrokeEvent {
 649                        keystroke: key_down_event.keystroke.clone(),
 650                        action: action.as_ref().map(|action| action.boxed_clone()),
 651                    },
 652                    self,
 653                );
 654                true
 655            });
 656    }
 657
 658    pub(crate) fn clear_pending_keystrokes(&mut self) {
 659        self.window
 660            .rendered_frame
 661            .dispatch_tree
 662            .clear_pending_keystrokes();
 663        self.window
 664            .next_frame
 665            .dispatch_tree
 666            .clear_pending_keystrokes();
 667    }
 668
 669    /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
 670    /// that are currently on the stack to be returned to the app.
 671    pub fn defer(&mut self, f: impl FnOnce(&mut WindowContext) + 'static) {
 672        let handle = self.window.handle;
 673        self.app.defer(move |cx| {
 674            handle.update(cx, |_, cx| f(cx)).ok();
 675        });
 676    }
 677
 678    /// Subscribe to events emitted by a model or view.
 679    /// The entity to which you're subscribing must implement the [`EventEmitter`] trait.
 680    /// 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.
 681    pub fn subscribe<Emitter, E, Evt>(
 682        &mut self,
 683        entity: &E,
 684        mut on_event: impl FnMut(E, &Evt, &mut WindowContext<'_>) + 'static,
 685    ) -> Subscription
 686    where
 687        Emitter: EventEmitter<Evt>,
 688        E: Entity<Emitter>,
 689        Evt: 'static,
 690    {
 691        let entity_id = entity.entity_id();
 692        let entity = entity.downgrade();
 693        let window_handle = self.window.handle;
 694        let (subscription, activate) = self.app.event_listeners.insert(
 695            entity_id,
 696            (
 697                TypeId::of::<Evt>(),
 698                Box::new(move |event, cx| {
 699                    window_handle
 700                        .update(cx, |_, cx| {
 701                            if let Some(handle) = E::upgrade_from(&entity) {
 702                                let event = event.downcast_ref().expect("invalid event type");
 703                                on_event(handle, event, cx);
 704                                true
 705                            } else {
 706                                false
 707                            }
 708                        })
 709                        .unwrap_or(false)
 710                }),
 711            ),
 712        );
 713        self.app.defer(move |_| activate());
 714        subscription
 715    }
 716
 717    /// Create an `AsyncWindowContext`, which has a static lifetime and can be held across
 718    /// await points in async code.
 719    pub fn to_async(&self) -> AsyncWindowContext {
 720        AsyncWindowContext::new(self.app.to_async(), self.window.handle)
 721    }
 722
 723    /// Schedule the given closure to be run directly after the current frame is rendered.
 724    pub fn on_next_frame(&mut self, callback: impl FnOnce(&mut WindowContext) + 'static) {
 725        let handle = self.window.handle;
 726        let display_id = self.window.display_id;
 727
 728        let mut frame_consumers = std::mem::take(&mut self.app.frame_consumers);
 729        if let Entry::Vacant(e) = frame_consumers.entry(display_id) {
 730            let (tx, mut rx) = mpsc::unbounded::<()>();
 731            self.platform.set_display_link_output_callback(
 732                display_id,
 733                Box::new(move |_current_time, _output_time| _ = tx.unbounded_send(())),
 734            );
 735
 736            let consumer_task = self.app.spawn(|cx| async move {
 737                while rx.next().await.is_some() {
 738                    cx.update(|cx| {
 739                        for callback in cx
 740                            .next_frame_callbacks
 741                            .get_mut(&display_id)
 742                            .unwrap()
 743                            .drain(..)
 744                            .collect::<SmallVec<[_; 32]>>()
 745                        {
 746                            callback(cx);
 747                        }
 748                    })
 749                    .ok();
 750
 751                    // Flush effects, then stop the display link if no new next_frame_callbacks have been added.
 752
 753                    cx.update(|cx| {
 754                        if cx.next_frame_callbacks.is_empty() {
 755                            cx.platform.stop_display_link(display_id);
 756                        }
 757                    })
 758                    .ok();
 759                }
 760            });
 761            e.insert(consumer_task);
 762        }
 763        debug_assert!(self.app.frame_consumers.is_empty());
 764        self.app.frame_consumers = frame_consumers;
 765
 766        if self.next_frame_callbacks.is_empty() {
 767            self.platform.start_display_link(display_id);
 768        }
 769
 770        self.next_frame_callbacks
 771            .entry(display_id)
 772            .or_default()
 773            .push(Box::new(move |cx: &mut AppContext| {
 774                cx.update_window(handle, |_root_view, cx| callback(cx)).ok();
 775            }));
 776    }
 777
 778    /// Spawn the future returned by the given closure on the application thread pool.
 779    /// The closure is provided a handle to the current window and an `AsyncWindowContext` for
 780    /// use within your future.
 781    pub fn spawn<Fut, R>(&mut self, f: impl FnOnce(AsyncWindowContext) -> Fut) -> Task<R>
 782    where
 783        R: 'static,
 784        Fut: Future<Output = R> + 'static,
 785    {
 786        self.app
 787            .spawn(|app| f(AsyncWindowContext::new(app, self.window.handle)))
 788    }
 789
 790    /// Update the global of the given type. The given closure is given simultaneous mutable
 791    /// access both to the global and the context.
 792    pub fn update_global<G, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R
 793    where
 794        G: 'static,
 795    {
 796        let mut global = self.app.lease_global::<G>();
 797        let result = f(&mut global, self);
 798        self.app.end_global_lease(global);
 799        result
 800    }
 801
 802    #[must_use]
 803    /// Add a node to the layout tree for the current frame. Takes the `Style` of the element for which
 804    /// layout is being requested, along with the layout ids of any children. This method is called during
 805    /// calls to the `Element::layout` trait method and enables any element to participate in layout.
 806    pub fn request_layout(
 807        &mut self,
 808        style: &Style,
 809        children: impl IntoIterator<Item = LayoutId>,
 810    ) -> LayoutId {
 811        self.app.layout_id_buffer.clear();
 812        self.app.layout_id_buffer.extend(children);
 813        let rem_size = self.rem_size();
 814
 815        self.window.layout_engine.as_mut().unwrap().request_layout(
 816            style,
 817            rem_size,
 818            &self.app.layout_id_buffer,
 819        )
 820    }
 821
 822    /// Add a node to the layout tree for the current frame. Instead of taking a `Style` and children,
 823    /// this variant takes a function that is invoked during layout so you can use arbitrary logic to
 824    /// determine the element's size. One place this is used internally is when measuring text.
 825    ///
 826    /// The given closure is invoked at layout time with the known dimensions and available space and
 827    /// returns a `Size`.
 828    pub fn request_measured_layout<
 829        F: FnMut(Size<Option<Pixels>>, Size<AvailableSpace>, &mut WindowContext) -> Size<Pixels>
 830            + 'static,
 831    >(
 832        &mut self,
 833        style: Style,
 834        measure: F,
 835    ) -> LayoutId {
 836        let rem_size = self.rem_size();
 837        self.window
 838            .layout_engine
 839            .as_mut()
 840            .unwrap()
 841            .request_measured_layout(style, rem_size, measure)
 842    }
 843
 844    pub(crate) fn layout_style(&self, layout_id: LayoutId) -> Option<&Style> {
 845        self.window
 846            .layout_engine
 847            .as_ref()
 848            .unwrap()
 849            .requested_style(layout_id)
 850    }
 851
 852    /// Compute the layout for the given id within the given available space.
 853    /// This method is called for its side effect, typically by the framework prior to painting.
 854    /// After calling it, you can request the bounds of the given layout node id or any descendant.
 855    pub fn compute_layout(&mut self, layout_id: LayoutId, available_space: Size<AvailableSpace>) {
 856        let mut layout_engine = self.window.layout_engine.take().unwrap();
 857        layout_engine.compute_layout(layout_id, available_space, self);
 858        self.window.layout_engine = Some(layout_engine);
 859    }
 860
 861    /// Obtain the bounds computed for the given LayoutId relative to the window. This method should not
 862    /// be invoked until the paint phase begins, and will usually be invoked by GPUI itself automatically
 863    /// in order to pass your element its `Bounds` automatically.
 864    pub fn layout_bounds(&mut self, layout_id: LayoutId) -> Bounds<Pixels> {
 865        let mut bounds = self
 866            .window
 867            .layout_engine
 868            .as_mut()
 869            .unwrap()
 870            .layout_bounds(layout_id)
 871            .map(Into::into);
 872        bounds.origin += self.element_offset();
 873        bounds
 874    }
 875
 876    fn window_bounds_changed(&mut self) {
 877        self.window.scale_factor = self.window.platform_window.scale_factor();
 878        self.window.viewport_size = self.window.platform_window.content_size();
 879        self.window.bounds = self.window.platform_window.bounds();
 880        self.window.display_id = self.window.platform_window.display().id();
 881        self.refresh();
 882
 883        self.window
 884            .bounds_observers
 885            .clone()
 886            .retain(&(), |callback| callback(self));
 887    }
 888
 889    /// Returns the bounds of the current window in the global coordinate space, which could span across multiple displays.
 890    pub fn window_bounds(&self) -> WindowBounds {
 891        self.window.bounds
 892    }
 893
 894    /// Returns the size of the drawable area within the window.
 895    pub fn viewport_size(&self) -> Size<Pixels> {
 896        self.window.viewport_size
 897    }
 898
 899    /// Returns whether this window is focused by the operating system (receiving key events).
 900    pub fn is_window_active(&self) -> bool {
 901        self.window.active
 902    }
 903
 904    /// Toggle zoom on the window.
 905    pub fn zoom_window(&self) {
 906        self.window.platform_window.zoom();
 907    }
 908
 909    /// Update the window's title at the platform level.
 910    pub fn set_window_title(&mut self, title: &str) {
 911        self.window.platform_window.set_title(title);
 912    }
 913
 914    /// Mark the window as dirty at the platform level.
 915    pub fn set_window_edited(&mut self, edited: bool) {
 916        self.window.platform_window.set_edited(edited);
 917    }
 918
 919    /// Determine the display on which the window is visible.
 920    pub fn display(&self) -> Option<Rc<dyn PlatformDisplay>> {
 921        self.platform
 922            .displays()
 923            .into_iter()
 924            .find(|display| display.id() == self.window.display_id)
 925    }
 926
 927    /// Show the platform character palette.
 928    pub fn show_character_palette(&self) {
 929        self.window.platform_window.show_character_palette();
 930    }
 931
 932    /// The scale factor of the display associated with the window. For example, it could
 933    /// return 2.0 for a "retina" display, indicating that each logical pixel should actually
 934    /// be rendered as two pixels on screen.
 935    pub fn scale_factor(&self) -> f32 {
 936        self.window.scale_factor
 937    }
 938
 939    /// The size of an em for the base font of the application. Adjusting this value allows the
 940    /// UI to scale, just like zooming a web page.
 941    pub fn rem_size(&self) -> Pixels {
 942        self.window.rem_size
 943    }
 944
 945    /// Sets the size of an em for the base font of the application. Adjusting this value allows the
 946    /// UI to scale, just like zooming a web page.
 947    pub fn set_rem_size(&mut self, rem_size: impl Into<Pixels>) {
 948        self.window.rem_size = rem_size.into();
 949    }
 950
 951    /// The line height associated with the current text style.
 952    pub fn line_height(&self) -> Pixels {
 953        let rem_size = self.rem_size();
 954        let text_style = self.text_style();
 955        text_style
 956            .line_height
 957            .to_pixels(text_style.font_size, rem_size)
 958    }
 959
 960    /// Call to prevent the default action of an event. Currently only used to prevent
 961    /// parent elements from becoming focused on mouse down.
 962    pub fn prevent_default(&mut self) {
 963        self.window.default_prevented = true;
 964    }
 965
 966    /// Obtain whether default has been prevented for the event currently being dispatched.
 967    pub fn default_prevented(&self) -> bool {
 968        self.window.default_prevented
 969    }
 970
 971    /// Register a mouse event listener on the window for the next frame. The type of event
 972    /// is determined by the first parameter of the given listener. When the next frame is rendered
 973    /// the listener will be cleared.
 974    pub fn on_mouse_event<Event: 'static>(
 975        &mut self,
 976        mut handler: impl FnMut(&Event, DispatchPhase, &mut WindowContext) + 'static,
 977    ) {
 978        let view_id = self.parent_view_id();
 979        let order = self.window.next_frame.z_index_stack.clone();
 980        self.window
 981            .next_frame
 982            .mouse_listeners
 983            .entry(TypeId::of::<Event>())
 984            .or_default()
 985            .push((
 986                order,
 987                view_id,
 988                Box::new(
 989                    move |event: &dyn Any, phase: DispatchPhase, cx: &mut WindowContext<'_>| {
 990                        handler(event.downcast_ref().unwrap(), phase, cx)
 991                    },
 992                ),
 993            ))
 994    }
 995
 996    /// Register a key event listener on the window for the next frame. The type of event
 997    /// is determined by the first parameter of the given listener. When the next frame is rendered
 998    /// the listener will be cleared.
 999    ///
1000    /// This is a fairly low-level method, so prefer using event handlers on elements unless you have
1001    /// a specific need to register a global listener.
1002    pub fn on_key_event<Event: 'static>(
1003        &mut self,
1004        listener: impl Fn(&Event, DispatchPhase, &mut WindowContext) + 'static,
1005    ) {
1006        self.window.next_frame.dispatch_tree.on_key_event(Rc::new(
1007            move |event: &dyn Any, phase, cx: &mut WindowContext<'_>| {
1008                if let Some(event) = event.downcast_ref::<Event>() {
1009                    listener(event, phase, cx)
1010                }
1011            },
1012        ));
1013    }
1014
1015    /// Register an action listener on the window for the next frame. The type of action
1016    /// is determined by the first parameter of the given listener. When the next frame is rendered
1017    /// the listener will be cleared.
1018    ///
1019    /// This is a fairly low-level method, so prefer using action handlers on elements unless you have
1020    /// a specific need to register a global listener.
1021    pub fn on_action(
1022        &mut self,
1023        action_type: TypeId,
1024        listener: impl Fn(&dyn Any, DispatchPhase, &mut WindowContext) + 'static,
1025    ) {
1026        self.window
1027            .next_frame
1028            .dispatch_tree
1029            .on_action(action_type, Rc::new(listener));
1030    }
1031
1032    /// Determine whether the given action is available along the dispatch path to the currently focused element.
1033    pub fn is_action_available(&self, action: &dyn Action) -> bool {
1034        let target = self
1035            .focused()
1036            .and_then(|focused_handle| {
1037                self.window
1038                    .rendered_frame
1039                    .dispatch_tree
1040                    .focusable_node_id(focused_handle.id)
1041            })
1042            .unwrap_or_else(|| self.window.rendered_frame.dispatch_tree.root_node_id());
1043        self.window
1044            .rendered_frame
1045            .dispatch_tree
1046            .is_action_available(action, target)
1047    }
1048
1049    /// The position of the mouse relative to the window.
1050    pub fn mouse_position(&self) -> Point<Pixels> {
1051        self.window.mouse_position
1052    }
1053
1054    /// The current state of the keyboard's modifiers
1055    pub fn modifiers(&self) -> Modifiers {
1056        self.window.modifiers
1057    }
1058
1059    /// Update the cursor style at the platform level.
1060    pub fn set_cursor_style(&mut self, style: CursorStyle) {
1061        let view_id = self.parent_view_id();
1062        self.window.next_frame.cursor_styles.insert(view_id, style);
1063        self.window.next_frame.requested_cursor_style = Some(style);
1064    }
1065
1066    /// Set a tooltip to be rendered for the upcoming frame
1067    pub fn set_tooltip(&mut self, tooltip: AnyTooltip) {
1068        let view_id = self.parent_view_id();
1069        self.window.next_frame.tooltip_request = Some(TooltipRequest { view_id, tooltip });
1070    }
1071
1072    /// Called during painting to track which z-index is on top at each pixel position
1073    pub fn add_opaque_layer(&mut self, bounds: Bounds<Pixels>) {
1074        let stacking_order = self.window.next_frame.z_index_stack.clone();
1075        let view_id = self.parent_view_id();
1076        let depth_map = &mut self.window.next_frame.depth_map;
1077        match depth_map.binary_search_by(|(level, _, _)| stacking_order.cmp(level)) {
1078            Ok(i) | Err(i) => depth_map.insert(i, (stacking_order, view_id, bounds)),
1079        }
1080    }
1081
1082    /// Returns true if there is no opaque layer containing the given point
1083    /// on top of the given level. Layers whose level is an extension of the
1084    /// level are not considered to be on top of the level.
1085    pub fn was_top_layer(&self, point: &Point<Pixels>, level: &StackingOrder) -> bool {
1086        for (opaque_level, _, bounds) in self.window.rendered_frame.depth_map.iter() {
1087            if level >= opaque_level {
1088                break;
1089            }
1090
1091            if bounds.contains(point) && !opaque_level.starts_with(level) {
1092                return false;
1093            }
1094        }
1095        true
1096    }
1097
1098    pub(crate) fn was_top_layer_under_active_drag(
1099        &self,
1100        point: &Point<Pixels>,
1101        level: &StackingOrder,
1102    ) -> bool {
1103        for (opaque_level, _, bounds) in self.window.rendered_frame.depth_map.iter() {
1104            if level >= opaque_level {
1105                break;
1106            }
1107            if opaque_level.starts_with(&[ACTIVE_DRAG_Z_INDEX]) {
1108                continue;
1109            }
1110
1111            if bounds.contains(point) && !opaque_level.starts_with(level) {
1112                return false;
1113            }
1114        }
1115        true
1116    }
1117
1118    /// Called during painting to get the current stacking order.
1119    pub fn stacking_order(&self) -> &StackingOrder {
1120        &self.window.next_frame.z_index_stack
1121    }
1122
1123    /// Paint one or more drop shadows into the scene for the next frame at the current z-index.
1124    pub fn paint_shadows(
1125        &mut self,
1126        bounds: Bounds<Pixels>,
1127        corner_radii: Corners<Pixels>,
1128        shadows: &[BoxShadow],
1129    ) {
1130        let scale_factor = self.scale_factor();
1131        let content_mask = self.content_mask();
1132        let view_id = self.parent_view_id();
1133        let window = &mut *self.window;
1134        for shadow in shadows {
1135            let mut shadow_bounds = bounds;
1136            shadow_bounds.origin += shadow.offset;
1137            shadow_bounds.dilate(shadow.spread_radius);
1138            window.next_frame.scene.insert(
1139                &window.next_frame.z_index_stack,
1140                Shadow {
1141                    view_id: view_id.into(),
1142                    layer_id: 0,
1143                    order: 0,
1144                    bounds: shadow_bounds.scale(scale_factor),
1145                    content_mask: content_mask.scale(scale_factor),
1146                    corner_radii: corner_radii.scale(scale_factor),
1147                    color: shadow.color,
1148                    blur_radius: shadow.blur_radius.scale(scale_factor),
1149                },
1150            );
1151        }
1152    }
1153
1154    /// Paint one or more quads into the scene for the next frame at the current stacking context.
1155    /// Quads are colored rectangular regions with an optional background, border, and corner radius.
1156    /// see [`fill`], [`outline`], and [`quad`] to construct this type.
1157    pub fn paint_quad(&mut self, quad: PaintQuad) {
1158        let scale_factor = self.scale_factor();
1159        let content_mask = self.content_mask();
1160        let view_id = self.parent_view_id();
1161
1162        let window = &mut *self.window;
1163        window.next_frame.scene.insert(
1164            &window.next_frame.z_index_stack,
1165            Quad {
1166                view_id: view_id.into(),
1167                layer_id: 0,
1168                order: 0,
1169                bounds: quad.bounds.scale(scale_factor),
1170                content_mask: content_mask.scale(scale_factor),
1171                background: quad.background,
1172                border_color: quad.border_color,
1173                corner_radii: quad.corner_radii.scale(scale_factor),
1174                border_widths: quad.border_widths.scale(scale_factor),
1175            },
1176        );
1177    }
1178
1179    /// Paint the given `Path` into the scene for the next frame at the current z-index.
1180    pub fn paint_path(&mut self, mut path: Path<Pixels>, color: impl Into<Hsla>) {
1181        let scale_factor = self.scale_factor();
1182        let content_mask = self.content_mask();
1183        let view_id = self.parent_view_id();
1184
1185        path.content_mask = content_mask;
1186        path.color = color.into();
1187        path.view_id = view_id.into();
1188        let window = &mut *self.window;
1189        window
1190            .next_frame
1191            .scene
1192            .insert(&window.next_frame.z_index_stack, path.scale(scale_factor));
1193    }
1194
1195    /// Paint an underline into the scene for the next frame at the current z-index.
1196    pub fn paint_underline(
1197        &mut self,
1198        origin: Point<Pixels>,
1199        width: Pixels,
1200        style: &UnderlineStyle,
1201    ) {
1202        let scale_factor = self.scale_factor();
1203        let height = if style.wavy {
1204            style.thickness * 3.
1205        } else {
1206            style.thickness
1207        };
1208        let bounds = Bounds {
1209            origin,
1210            size: size(width, height),
1211        };
1212        let content_mask = self.content_mask();
1213        let view_id = self.parent_view_id();
1214
1215        let window = &mut *self.window;
1216        window.next_frame.scene.insert(
1217            &window.next_frame.z_index_stack,
1218            Underline {
1219                view_id: view_id.into(),
1220                layer_id: 0,
1221                order: 0,
1222                bounds: bounds.scale(scale_factor),
1223                content_mask: content_mask.scale(scale_factor),
1224                thickness: style.thickness.scale(scale_factor),
1225                color: style.color.unwrap_or_default(),
1226                wavy: style.wavy,
1227            },
1228        );
1229    }
1230
1231    /// Paint a monochrome (non-emoji) glyph into the scene for the next frame at the current z-index.
1232    /// The y component of the origin is the baseline of the glyph.
1233    pub fn paint_glyph(
1234        &mut self,
1235        origin: Point<Pixels>,
1236        font_id: FontId,
1237        glyph_id: GlyphId,
1238        font_size: Pixels,
1239        color: Hsla,
1240    ) -> Result<()> {
1241        let scale_factor = self.scale_factor();
1242        let glyph_origin = origin.scale(scale_factor);
1243        let subpixel_variant = Point {
1244            x: (glyph_origin.x.0.fract() * SUBPIXEL_VARIANTS as f32).floor() as u8,
1245            y: (glyph_origin.y.0.fract() * SUBPIXEL_VARIANTS as f32).floor() as u8,
1246        };
1247        let params = RenderGlyphParams {
1248            font_id,
1249            glyph_id,
1250            font_size,
1251            subpixel_variant,
1252            scale_factor,
1253            is_emoji: false,
1254        };
1255
1256        let raster_bounds = self.text_system().raster_bounds(&params)?;
1257        if !raster_bounds.is_zero() {
1258            let tile =
1259                self.window
1260                    .sprite_atlas
1261                    .get_or_insert_with(&params.clone().into(), &mut || {
1262                        let (size, bytes) = self.text_system().rasterize_glyph(&params)?;
1263                        Ok((size, Cow::Owned(bytes)))
1264                    })?;
1265            let bounds = Bounds {
1266                origin: glyph_origin.map(|px| px.floor()) + raster_bounds.origin.map(Into::into),
1267                size: tile.bounds.size.map(Into::into),
1268            };
1269            let content_mask = self.content_mask().scale(scale_factor);
1270            let view_id = self.parent_view_id();
1271            let window = &mut *self.window;
1272            window.next_frame.scene.insert(
1273                &window.next_frame.z_index_stack,
1274                MonochromeSprite {
1275                    view_id: view_id.into(),
1276                    layer_id: 0,
1277                    order: 0,
1278                    bounds,
1279                    content_mask,
1280                    color,
1281                    tile,
1282                },
1283            );
1284        }
1285        Ok(())
1286    }
1287
1288    /// Paint an emoji glyph into the scene for the next frame at the current z-index.
1289    /// The y component of the origin is the baseline of the glyph.
1290    pub fn paint_emoji(
1291        &mut self,
1292        origin: Point<Pixels>,
1293        font_id: FontId,
1294        glyph_id: GlyphId,
1295        font_size: Pixels,
1296    ) -> Result<()> {
1297        let scale_factor = self.scale_factor();
1298        let glyph_origin = origin.scale(scale_factor);
1299        let params = RenderGlyphParams {
1300            font_id,
1301            glyph_id,
1302            font_size,
1303            // We don't render emojis with subpixel variants.
1304            subpixel_variant: Default::default(),
1305            scale_factor,
1306            is_emoji: true,
1307        };
1308
1309        let raster_bounds = self.text_system().raster_bounds(&params)?;
1310        if !raster_bounds.is_zero() {
1311            let tile =
1312                self.window
1313                    .sprite_atlas
1314                    .get_or_insert_with(&params.clone().into(), &mut || {
1315                        let (size, bytes) = self.text_system().rasterize_glyph(&params)?;
1316                        Ok((size, Cow::Owned(bytes)))
1317                    })?;
1318            let bounds = Bounds {
1319                origin: glyph_origin.map(|px| px.floor()) + raster_bounds.origin.map(Into::into),
1320                size: tile.bounds.size.map(Into::into),
1321            };
1322            let content_mask = self.content_mask().scale(scale_factor);
1323            let view_id = self.parent_view_id();
1324            let window = &mut *self.window;
1325
1326            window.next_frame.scene.insert(
1327                &window.next_frame.z_index_stack,
1328                PolychromeSprite {
1329                    view_id: view_id.into(),
1330                    layer_id: 0,
1331                    order: 0,
1332                    bounds,
1333                    corner_radii: Default::default(),
1334                    content_mask,
1335                    tile,
1336                    grayscale: false,
1337                },
1338            );
1339        }
1340        Ok(())
1341    }
1342
1343    /// Paint a monochrome SVG into the scene for the next frame at the current stacking context.
1344    pub fn paint_svg(
1345        &mut self,
1346        bounds: Bounds<Pixels>,
1347        path: SharedString,
1348        color: Hsla,
1349    ) -> Result<()> {
1350        let scale_factor = self.scale_factor();
1351        let bounds = bounds.scale(scale_factor);
1352        // Render the SVG at twice the size to get a higher quality result.
1353        let params = RenderSvgParams {
1354            path,
1355            size: bounds
1356                .size
1357                .map(|pixels| DevicePixels::from((pixels.0 * 2.).ceil() as i32)),
1358        };
1359
1360        let tile =
1361            self.window
1362                .sprite_atlas
1363                .get_or_insert_with(&params.clone().into(), &mut || {
1364                    let bytes = self.svg_renderer.render(&params)?;
1365                    Ok((params.size, Cow::Owned(bytes)))
1366                })?;
1367        let content_mask = self.content_mask().scale(scale_factor);
1368        let view_id = self.parent_view_id();
1369
1370        let window = &mut *self.window;
1371        window.next_frame.scene.insert(
1372            &window.next_frame.z_index_stack,
1373            MonochromeSprite {
1374                view_id: view_id.into(),
1375                layer_id: 0,
1376                order: 0,
1377                bounds,
1378                content_mask,
1379                color,
1380                tile,
1381            },
1382        );
1383
1384        Ok(())
1385    }
1386
1387    /// Paint an image into the scene for the next frame at the current z-index.
1388    pub fn paint_image(
1389        &mut self,
1390        bounds: Bounds<Pixels>,
1391        corner_radii: Corners<Pixels>,
1392        data: Arc<ImageData>,
1393        grayscale: bool,
1394    ) -> Result<()> {
1395        let scale_factor = self.scale_factor();
1396        let bounds = bounds.scale(scale_factor);
1397        let params = RenderImageParams { image_id: data.id };
1398
1399        let tile = self
1400            .window
1401            .sprite_atlas
1402            .get_or_insert_with(&params.clone().into(), &mut || {
1403                Ok((data.size(), Cow::Borrowed(data.as_bytes())))
1404            })?;
1405        let content_mask = self.content_mask().scale(scale_factor);
1406        let corner_radii = corner_radii.scale(scale_factor);
1407        let view_id = self.parent_view_id();
1408
1409        let window = &mut *self.window;
1410        window.next_frame.scene.insert(
1411            &window.next_frame.z_index_stack,
1412            PolychromeSprite {
1413                view_id: view_id.into(),
1414                layer_id: 0,
1415                order: 0,
1416                bounds,
1417                content_mask,
1418                corner_radii,
1419                tile,
1420                grayscale,
1421            },
1422        );
1423        Ok(())
1424    }
1425
1426    /// Paint a surface into the scene for the next frame at the current z-index.
1427    pub fn paint_surface(&mut self, bounds: Bounds<Pixels>, image_buffer: CVImageBuffer) {
1428        let scale_factor = self.scale_factor();
1429        let bounds = bounds.scale(scale_factor);
1430        let content_mask = self.content_mask().scale(scale_factor);
1431        let view_id = self.parent_view_id();
1432        let window = &mut *self.window;
1433        window.next_frame.scene.insert(
1434            &window.next_frame.z_index_stack,
1435            Surface {
1436                view_id: view_id.into(),
1437                layer_id: 0,
1438                order: 0,
1439                bounds,
1440                content_mask,
1441                image_buffer,
1442            },
1443        );
1444    }
1445
1446    pub(crate) fn reuse_view(&mut self) {
1447        let view_id = self.parent_view_id();
1448        let grafted_view_ids = self
1449            .window
1450            .next_frame
1451            .dispatch_tree
1452            .reuse_view(view_id, &mut self.window.rendered_frame.dispatch_tree);
1453        for view_id in grafted_view_ids {
1454            assert!(self.window.next_frame.reused_views.insert(view_id));
1455
1456            // Reuse the previous input handler requested during painting of the reused view.
1457            if self
1458                .window
1459                .rendered_frame
1460                .requested_input_handler
1461                .as_ref()
1462                .map_or(false, |requested| requested.view_id == view_id)
1463            {
1464                self.window.next_frame.requested_input_handler =
1465                    self.window.rendered_frame.requested_input_handler.take();
1466            }
1467
1468            // Reuse the tooltip previously requested during painting of the reused view.
1469            if self
1470                .window
1471                .rendered_frame
1472                .tooltip_request
1473                .as_ref()
1474                .map_or(false, |requested| requested.view_id == view_id)
1475            {
1476                self.window.next_frame.tooltip_request =
1477                    self.window.rendered_frame.tooltip_request.take();
1478            }
1479
1480            // Reuse the cursor styles previously requested during painting of the reused view.
1481            if let Some(style) = self.window.rendered_frame.cursor_styles.remove(&view_id) {
1482                self.window.next_frame.cursor_styles.insert(view_id, style);
1483                self.window.next_frame.requested_cursor_style = Some(style);
1484            }
1485        }
1486    }
1487
1488    /// Draw pixels to the display for this window based on the contents of its scene.
1489    pub(crate) fn draw(&mut self) {
1490        self.window.dirty = false;
1491        self.window.drawing = true;
1492
1493        #[cfg(any(test, feature = "test-support"))]
1494        {
1495            self.window.focus_invalidated = false;
1496        }
1497
1498        if let Some(requested_handler) = self.window.rendered_frame.requested_input_handler.as_mut()
1499        {
1500            requested_handler.handler = self.window.platform_window.take_input_handler();
1501        }
1502
1503        let root_view = self.window.root_view.take().unwrap();
1504
1505        self.with_z_index(0, |cx| {
1506            cx.with_key_dispatch(Some(KeyContext::default()), None, |_, cx| {
1507                for (action_type, action_listeners) in &cx.app.global_action_listeners {
1508                    for action_listener in action_listeners.iter().cloned() {
1509                        cx.window.next_frame.dispatch_tree.on_action(
1510                            *action_type,
1511                            Rc::new(move |action: &dyn Any, phase, cx: &mut WindowContext<'_>| {
1512                                action_listener(action, phase, cx)
1513                            }),
1514                        )
1515                    }
1516                }
1517
1518                let available_space = cx.window.viewport_size.map(Into::into);
1519                root_view.draw(Point::default(), available_space, cx);
1520            })
1521        });
1522
1523        if let Some(active_drag) = self.app.active_drag.take() {
1524            self.with_z_index(ACTIVE_DRAG_Z_INDEX, |cx| {
1525                let offset = cx.mouse_position() - active_drag.cursor_offset;
1526                let available_space = size(AvailableSpace::MinContent, AvailableSpace::MinContent);
1527                active_drag.view.draw(offset, available_space, cx);
1528            });
1529            self.active_drag = Some(active_drag);
1530        } else if let Some(tooltip_request) = self.window.next_frame.tooltip_request.take() {
1531            self.with_z_index(1, |cx| {
1532                let available_space = size(AvailableSpace::MinContent, AvailableSpace::MinContent);
1533                tooltip_request.tooltip.view.draw(
1534                    tooltip_request.tooltip.cursor_offset,
1535                    available_space,
1536                    cx,
1537                );
1538            });
1539            self.window.next_frame.tooltip_request = Some(tooltip_request);
1540        }
1541        self.window.dirty_views.clear();
1542
1543        self.window
1544            .next_frame
1545            .dispatch_tree
1546            .preserve_pending_keystrokes(
1547                &mut self.window.rendered_frame.dispatch_tree,
1548                self.window.focus,
1549            );
1550        self.window.next_frame.focus = self.window.focus;
1551        self.window.next_frame.window_active = self.window.active;
1552        self.window.root_view = Some(root_view);
1553
1554        // Set the cursor only if we're the active window.
1555        let cursor_style = self
1556            .window
1557            .next_frame
1558            .requested_cursor_style
1559            .take()
1560            .unwrap_or(CursorStyle::Arrow);
1561        if self.is_window_active() {
1562            self.platform.set_cursor_style(cursor_style);
1563        }
1564
1565        // Register requested input handler with the platform window.
1566        if let Some(requested_input) = self.window.next_frame.requested_input_handler.as_mut() {
1567            if let Some(handler) = requested_input.handler.take() {
1568                self.window.platform_window.set_input_handler(handler);
1569            }
1570        }
1571
1572        self.window.layout_engine.as_mut().unwrap().clear();
1573        self.text_system()
1574            .finish_frame(&self.window.next_frame.reused_views);
1575        self.window
1576            .next_frame
1577            .finish(&mut self.window.rendered_frame);
1578        ELEMENT_ARENA.with_borrow_mut(|element_arena| element_arena.clear());
1579
1580        let previous_focus_path = self.window.rendered_frame.focus_path();
1581        let previous_window_active = self.window.rendered_frame.window_active;
1582        mem::swap(&mut self.window.rendered_frame, &mut self.window.next_frame);
1583        self.window.next_frame.clear();
1584        let current_focus_path = self.window.rendered_frame.focus_path();
1585        let current_window_active = self.window.rendered_frame.window_active;
1586
1587        if previous_focus_path != current_focus_path
1588            || previous_window_active != current_window_active
1589        {
1590            if !previous_focus_path.is_empty() && current_focus_path.is_empty() {
1591                self.window
1592                    .focus_lost_listeners
1593                    .clone()
1594                    .retain(&(), |listener| listener(self));
1595            }
1596
1597            let event = FocusEvent {
1598                previous_focus_path: if previous_window_active {
1599                    previous_focus_path
1600                } else {
1601                    Default::default()
1602                },
1603                current_focus_path: if current_window_active {
1604                    current_focus_path
1605                } else {
1606                    Default::default()
1607                },
1608            };
1609            self.window
1610                .focus_listeners
1611                .clone()
1612                .retain(&(), |listener| listener(&event, self));
1613        }
1614
1615        self.window
1616            .platform_window
1617            .draw(&self.window.rendered_frame.scene);
1618        self.window.refreshing = false;
1619        self.window.drawing = false;
1620    }
1621
1622    /// Dispatch a mouse or keyboard event on the window.
1623    pub fn dispatch_event(&mut self, event: InputEvent) -> bool {
1624        // Handlers may set this to false by calling `stop_propagation`.
1625        self.app.propagate_event = true;
1626        // Handlers may set this to true by calling `prevent_default`.
1627        self.window.default_prevented = false;
1628
1629        let event = match event {
1630            // Track the mouse position with our own state, since accessing the platform
1631            // API for the mouse position can only occur on the main thread.
1632            InputEvent::MouseMove(mouse_move) => {
1633                self.window.mouse_position = mouse_move.position;
1634                self.window.modifiers = mouse_move.modifiers;
1635                InputEvent::MouseMove(mouse_move)
1636            }
1637            InputEvent::MouseDown(mouse_down) => {
1638                self.window.mouse_position = mouse_down.position;
1639                self.window.modifiers = mouse_down.modifiers;
1640                InputEvent::MouseDown(mouse_down)
1641            }
1642            InputEvent::MouseUp(mouse_up) => {
1643                self.window.mouse_position = mouse_up.position;
1644                self.window.modifiers = mouse_up.modifiers;
1645                InputEvent::MouseUp(mouse_up)
1646            }
1647            InputEvent::MouseExited(mouse_exited) => {
1648                self.window.modifiers = mouse_exited.modifiers;
1649                InputEvent::MouseExited(mouse_exited)
1650            }
1651            InputEvent::ModifiersChanged(modifiers_changed) => {
1652                self.window.modifiers = modifiers_changed.modifiers;
1653                InputEvent::ModifiersChanged(modifiers_changed)
1654            }
1655            InputEvent::ScrollWheel(scroll_wheel) => {
1656                self.window.mouse_position = scroll_wheel.position;
1657                self.window.modifiers = scroll_wheel.modifiers;
1658                InputEvent::ScrollWheel(scroll_wheel)
1659            }
1660            // Translate dragging and dropping of external files from the operating system
1661            // to internal drag and drop events.
1662            InputEvent::FileDrop(file_drop) => match file_drop {
1663                FileDropEvent::Entered { position, paths } => {
1664                    self.window.mouse_position = position;
1665                    if self.active_drag.is_none() {
1666                        self.active_drag = Some(AnyDrag {
1667                            value: Box::new(paths.clone()),
1668                            view: self.new_view(|_| paths).into(),
1669                            cursor_offset: position,
1670                        });
1671                    }
1672                    InputEvent::MouseMove(MouseMoveEvent {
1673                        position,
1674                        pressed_button: Some(MouseButton::Left),
1675                        modifiers: Modifiers::default(),
1676                    })
1677                }
1678                FileDropEvent::Pending { position } => {
1679                    self.window.mouse_position = position;
1680                    InputEvent::MouseMove(MouseMoveEvent {
1681                        position,
1682                        pressed_button: Some(MouseButton::Left),
1683                        modifiers: Modifiers::default(),
1684                    })
1685                }
1686                FileDropEvent::Submit { position } => {
1687                    self.activate(true);
1688                    self.window.mouse_position = position;
1689                    InputEvent::MouseUp(MouseUpEvent {
1690                        button: MouseButton::Left,
1691                        position,
1692                        modifiers: Modifiers::default(),
1693                        click_count: 1,
1694                    })
1695                }
1696                FileDropEvent::Exited => InputEvent::MouseUp(MouseUpEvent {
1697                    button: MouseButton::Left,
1698                    position: Point::default(),
1699                    modifiers: Modifiers::default(),
1700                    click_count: 1,
1701                }),
1702            },
1703            InputEvent::KeyDown(_) | InputEvent::KeyUp(_) => event,
1704        };
1705
1706        if let Some(any_mouse_event) = event.mouse_event() {
1707            self.dispatch_mouse_event(any_mouse_event);
1708        } else if let Some(any_key_event) = event.keyboard_event() {
1709            self.dispatch_key_event(any_key_event);
1710        }
1711
1712        !self.app.propagate_event
1713    }
1714
1715    fn dispatch_mouse_event(&mut self, event: &dyn Any) {
1716        if let Some(mut handlers) = self
1717            .window
1718            .rendered_frame
1719            .mouse_listeners
1720            .remove(&event.type_id())
1721        {
1722            // Because handlers may add other handlers, we sort every time.
1723            handlers.sort_by(|(a, _, _), (b, _, _)| a.cmp(b));
1724
1725            // Capture phase, events bubble from back to front. Handlers for this phase are used for
1726            // special purposes, such as detecting events outside of a given Bounds.
1727            for (_, _, handler) in &mut handlers {
1728                handler(event, DispatchPhase::Capture, self);
1729                if !self.app.propagate_event {
1730                    break;
1731                }
1732            }
1733
1734            // Bubble phase, where most normal handlers do their work.
1735            if self.app.propagate_event {
1736                for (_, _, handler) in handlers.iter_mut().rev() {
1737                    handler(event, DispatchPhase::Bubble, self);
1738                    if !self.app.propagate_event {
1739                        break;
1740                    }
1741                }
1742            }
1743
1744            self.window
1745                .rendered_frame
1746                .mouse_listeners
1747                .insert(event.type_id(), handlers);
1748        }
1749
1750        if self.app.propagate_event && self.has_active_drag() {
1751            if event.is::<MouseMoveEvent>() {
1752                // If this was a mouse move event, redraw the window so that the
1753                // active drag can follow the mouse cursor.
1754                self.refresh();
1755            } else if event.is::<MouseUpEvent>() {
1756                // If this was a mouse up event, cancel the active drag and redraw
1757                // the window.
1758                self.active_drag = None;
1759                self.refresh();
1760            }
1761        }
1762    }
1763
1764    fn dispatch_key_event(&mut self, event: &dyn Any) {
1765        let node_id = self
1766            .window
1767            .focus
1768            .and_then(|focus_id| {
1769                self.window
1770                    .rendered_frame
1771                    .dispatch_tree
1772                    .focusable_node_id(focus_id)
1773            })
1774            .unwrap_or_else(|| self.window.rendered_frame.dispatch_tree.root_node_id());
1775
1776        let dispatch_path = self
1777            .window
1778            .rendered_frame
1779            .dispatch_tree
1780            .dispatch_path(node_id);
1781
1782        let mut actions: Vec<Box<dyn Action>> = Vec::new();
1783
1784        let mut context_stack: SmallVec<[KeyContext; 16]> = SmallVec::new();
1785        for node_id in &dispatch_path {
1786            let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1787
1788            if let Some(context) = node.context.clone() {
1789                context_stack.push(context);
1790            }
1791        }
1792
1793        for node_id in dispatch_path.iter().rev() {
1794            // Match keystrokes
1795            let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1796            if node.context.is_some() {
1797                if let Some(key_down_event) = event.downcast_ref::<KeyDownEvent>() {
1798                    let mut new_actions = self
1799                        .window
1800                        .rendered_frame
1801                        .dispatch_tree
1802                        .dispatch_key(&key_down_event.keystroke, &context_stack);
1803                    actions.append(&mut new_actions);
1804                }
1805
1806                context_stack.pop();
1807            }
1808        }
1809
1810        if !actions.is_empty() {
1811            self.clear_pending_keystrokes();
1812        }
1813
1814        self.propagate_event = true;
1815        for action in actions {
1816            self.dispatch_action_on_node(node_id, action.boxed_clone());
1817            if !self.propagate_event {
1818                self.dispatch_keystroke_observers(event, Some(action));
1819                return;
1820            }
1821        }
1822
1823        // Capture phase
1824        for node_id in &dispatch_path {
1825            let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1826
1827            for key_listener in node.key_listeners.clone() {
1828                key_listener(event, DispatchPhase::Capture, self);
1829                if !self.propagate_event {
1830                    return;
1831                }
1832            }
1833        }
1834
1835        // Bubble phase
1836        for node_id in dispatch_path.iter().rev() {
1837            // Handle low level key events
1838            let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1839            for key_listener in node.key_listeners.clone() {
1840                key_listener(event, DispatchPhase::Bubble, self);
1841                if !self.propagate_event {
1842                    return;
1843                }
1844            }
1845        }
1846
1847        self.dispatch_keystroke_observers(event, None);
1848    }
1849
1850    /// Determine whether a potential multi-stroke key binding is in progress on this window.
1851    pub fn has_pending_keystrokes(&self) -> bool {
1852        self.window
1853            .rendered_frame
1854            .dispatch_tree
1855            .has_pending_keystrokes()
1856    }
1857
1858    fn dispatch_action_on_node(&mut self, node_id: DispatchNodeId, action: Box<dyn Action>) {
1859        let dispatch_path = self
1860            .window
1861            .rendered_frame
1862            .dispatch_tree
1863            .dispatch_path(node_id);
1864
1865        // Capture phase
1866        for node_id in &dispatch_path {
1867            let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1868            for DispatchActionListener {
1869                action_type,
1870                listener,
1871            } in node.action_listeners.clone()
1872            {
1873                let any_action = action.as_any();
1874                if action_type == any_action.type_id() {
1875                    listener(any_action, DispatchPhase::Capture, self);
1876                    if !self.propagate_event {
1877                        return;
1878                    }
1879                }
1880            }
1881        }
1882        // Bubble phase
1883        for node_id in dispatch_path.iter().rev() {
1884            let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1885            for DispatchActionListener {
1886                action_type,
1887                listener,
1888            } in node.action_listeners.clone()
1889            {
1890                let any_action = action.as_any();
1891                if action_type == any_action.type_id() {
1892                    self.propagate_event = false; // Actions stop propagation by default during the bubble phase
1893                    listener(any_action, DispatchPhase::Bubble, self);
1894                    if !self.propagate_event {
1895                        return;
1896                    }
1897                }
1898            }
1899        }
1900    }
1901
1902    /// Register the given handler to be invoked whenever the global of the given type
1903    /// is updated.
1904    pub fn observe_global<G: 'static>(
1905        &mut self,
1906        f: impl Fn(&mut WindowContext<'_>) + 'static,
1907    ) -> Subscription {
1908        let window_handle = self.window.handle;
1909        let (subscription, activate) = self.global_observers.insert(
1910            TypeId::of::<G>(),
1911            Box::new(move |cx| window_handle.update(cx, |_, cx| f(cx)).is_ok()),
1912        );
1913        self.app.defer(move |_| activate());
1914        subscription
1915    }
1916
1917    /// Focus the current window and bring it to the foreground at the platform level.
1918    pub fn activate_window(&self) {
1919        self.window.platform_window.activate();
1920    }
1921
1922    /// Minimize the current window at the platform level.
1923    pub fn minimize_window(&self) {
1924        self.window.platform_window.minimize();
1925    }
1926
1927    /// Toggle full screen status on the current window at the platform level.
1928    pub fn toggle_full_screen(&self) {
1929        self.window.platform_window.toggle_full_screen();
1930    }
1931
1932    /// Present a platform dialog.
1933    /// The provided message will be presented, along with buttons for each answer.
1934    /// When a button is clicked, the returned Receiver will receive the index of the clicked button.
1935    pub fn prompt(
1936        &self,
1937        level: PromptLevel,
1938        message: &str,
1939        answers: &[&str],
1940    ) -> oneshot::Receiver<usize> {
1941        self.window.platform_window.prompt(level, message, answers)
1942    }
1943
1944    /// Returns all available actions for the focused element.
1945    pub fn available_actions(&self) -> Vec<Box<dyn Action>> {
1946        let node_id = self
1947            .window
1948            .focus
1949            .and_then(|focus_id| {
1950                self.window
1951                    .rendered_frame
1952                    .dispatch_tree
1953                    .focusable_node_id(focus_id)
1954            })
1955            .unwrap_or_else(|| self.window.rendered_frame.dispatch_tree.root_node_id());
1956
1957        self.window
1958            .rendered_frame
1959            .dispatch_tree
1960            .available_actions(node_id)
1961    }
1962
1963    /// Returns key bindings that invoke the given action on the currently focused element.
1964    pub fn bindings_for_action(&self, action: &dyn Action) -> Vec<KeyBinding> {
1965        self.window
1966            .rendered_frame
1967            .dispatch_tree
1968            .bindings_for_action(
1969                action,
1970                &self.window.rendered_frame.dispatch_tree.context_stack,
1971            )
1972    }
1973
1974    /// Returns any bindings that would invoke the given action on the given focus handle if it were focused.
1975    pub fn bindings_for_action_in(
1976        &self,
1977        action: &dyn Action,
1978        focus_handle: &FocusHandle,
1979    ) -> Vec<KeyBinding> {
1980        let dispatch_tree = &self.window.rendered_frame.dispatch_tree;
1981
1982        let Some(node_id) = dispatch_tree.focusable_node_id(focus_handle.id) else {
1983            return vec![];
1984        };
1985        let context_stack = dispatch_tree
1986            .dispatch_path(node_id)
1987            .into_iter()
1988            .filter_map(|node_id| dispatch_tree.node(node_id).context.clone())
1989            .collect();
1990        dispatch_tree.bindings_for_action(action, &context_stack)
1991    }
1992
1993    /// Returns a generic event listener that invokes the given listener with the view and context associated with the given view handle.
1994    pub fn listener_for<V: Render, E>(
1995        &self,
1996        view: &View<V>,
1997        f: impl Fn(&mut V, &E, &mut ViewContext<V>) + 'static,
1998    ) -> impl Fn(&E, &mut WindowContext) + 'static {
1999        let view = view.downgrade();
2000        move |e: &E, cx: &mut WindowContext| {
2001            view.update(cx, |view, cx| f(view, e, cx)).ok();
2002        }
2003    }
2004
2005    /// Returns a generic handler that invokes the given handler with the view and context associated with the given view handle.
2006    pub fn handler_for<V: Render>(
2007        &self,
2008        view: &View<V>,
2009        f: impl Fn(&mut V, &mut ViewContext<V>) + 'static,
2010    ) -> impl Fn(&mut WindowContext) {
2011        let view = view.downgrade();
2012        move |cx: &mut WindowContext| {
2013            view.update(cx, |view, cx| f(view, cx)).ok();
2014        }
2015    }
2016
2017    /// Invoke the given function with the given focus handle present on the key dispatch stack.
2018    /// 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.
2019    pub fn with_key_dispatch<R>(
2020        &mut self,
2021        context: Option<KeyContext>,
2022        focus_handle: Option<FocusHandle>,
2023        f: impl FnOnce(Option<FocusHandle>, &mut Self) -> R,
2024    ) -> R {
2025        let window = &mut self.window;
2026        let focus_id = focus_handle.as_ref().map(|handle| handle.id);
2027        window
2028            .next_frame
2029            .dispatch_tree
2030            .push_node(context.clone(), focus_id, None);
2031
2032        let result = f(focus_handle, self);
2033
2034        self.window.next_frame.dispatch_tree.pop_node();
2035
2036        result
2037    }
2038
2039    /// Invoke the given function with the given view id present on the view stack.
2040    /// This is a fairly low-level method used to layout views.
2041    pub fn with_view_id<R>(&mut self, view_id: EntityId, f: impl FnOnce(&mut Self) -> R) -> R {
2042        let text_system = self.text_system().clone();
2043        text_system.with_view(view_id, || {
2044            if self.window.next_frame.view_stack.last() == Some(&view_id) {
2045                return f(self);
2046            } else {
2047                self.window.next_frame.view_stack.push(view_id);
2048                let result = f(self);
2049                self.window.next_frame.view_stack.pop();
2050                result
2051            }
2052        })
2053    }
2054
2055    /// Invoke the given function with the given view id present on the view stack.
2056    /// This is a fairly low-level method used to paint views.
2057    pub fn paint_view<R>(&mut self, view_id: EntityId, f: impl FnOnce(&mut Self) -> R) -> R {
2058        let text_system = self.text_system().clone();
2059        text_system.with_view(view_id, || {
2060            if self.window.next_frame.view_stack.last() == Some(&view_id) {
2061                return f(self);
2062            } else {
2063                self.window.next_frame.view_stack.push(view_id);
2064                self.window
2065                    .next_frame
2066                    .dispatch_tree
2067                    .push_node(None, None, Some(view_id));
2068                let result = f(self);
2069                self.window.next_frame.dispatch_tree.pop_node();
2070                self.window.next_frame.view_stack.pop();
2071                result
2072            }
2073        })
2074    }
2075
2076    /// Update or initialize state for an element with the given id that lives across multiple
2077    /// frames. If an element with this id existed in the rendered frame, its state will be passed
2078    /// to the given closure. The state returned by the closure will be stored so it can be referenced
2079    /// when drawing the next frame.
2080    pub(crate) fn with_element_state<S, R>(
2081        &mut self,
2082        id: ElementId,
2083        f: impl FnOnce(Option<S>, &mut Self) -> (R, S),
2084    ) -> R
2085    where
2086        S: 'static,
2087    {
2088        self.with_element_id(Some(id), |cx| {
2089            let global_id = cx.window().element_id_stack.clone();
2090
2091            if let Some(any) = cx
2092                .window_mut()
2093                .next_frame
2094                .element_states
2095                .remove(&global_id)
2096                .or_else(|| {
2097                    cx.window_mut()
2098                        .rendered_frame
2099                        .element_states
2100                        .remove(&global_id)
2101                })
2102            {
2103                let ElementStateBox {
2104                    inner,
2105                    parent_view_id,
2106                    #[cfg(debug_assertions)]
2107                    type_name
2108                } = any;
2109                // Using the extra inner option to avoid needing to reallocate a new box.
2110                let mut state_box = inner
2111                    .downcast::<Option<S>>()
2112                    .map_err(|_| {
2113                        #[cfg(debug_assertions)]
2114                        {
2115                            anyhow!(
2116                                "invalid element state type for id, requested_type {:?}, actual type: {:?}",
2117                                std::any::type_name::<S>(),
2118                                type_name
2119                            )
2120                        }
2121
2122                        #[cfg(not(debug_assertions))]
2123                        {
2124                            anyhow!(
2125                                "invalid element state type for id, requested_type {:?}",
2126                                std::any::type_name::<S>(),
2127                            )
2128                        }
2129                    })
2130                    .unwrap();
2131
2132                // Actual: Option<AnyElement> <- View
2133                // Requested: () <- AnyElemet
2134                let state = state_box
2135                    .take()
2136                    .expect("element state is already on the stack");
2137                let (result, state) = f(Some(state), cx);
2138                state_box.replace(state);
2139                cx.window_mut()
2140                    .next_frame
2141                    .element_states
2142                    .insert(global_id, ElementStateBox {
2143                        inner: state_box,
2144                        parent_view_id,
2145                        #[cfg(debug_assertions)]
2146                        type_name
2147                    });
2148                result
2149            } else {
2150                let (result, state) = f(None, cx);
2151                let parent_view_id = cx.parent_view_id();
2152                cx.window_mut()
2153                    .next_frame
2154                    .element_states
2155                    .insert(global_id,
2156                        ElementStateBox {
2157                            inner: Box::new(Some(state)),
2158                            parent_view_id,
2159                            #[cfg(debug_assertions)]
2160                            type_name: std::any::type_name::<S>()
2161                        }
2162
2163                    );
2164                result
2165            }
2166        })
2167    }
2168
2169    fn parent_view_id(&self) -> EntityId {
2170        *self
2171            .window
2172            .next_frame
2173            .view_stack
2174            .last()
2175            .expect("a view should always be on the stack while drawing")
2176    }
2177
2178    /// Set an input handler, such as [`ElementInputHandler`][element_input_handler], which interfaces with the
2179    /// platform to receive textual input with proper integration with concerns such
2180    /// as IME interactions. This handler will be active for the upcoming frame until the following frame is
2181    /// rendered.
2182    ///
2183    /// [element_input_handler]: crate::ElementInputHandler
2184    pub fn handle_input(
2185        &mut self,
2186        focus_handle: &FocusHandle,
2187        input_handler: impl PlatformInputHandler,
2188    ) {
2189        if focus_handle.is_focused(self) {
2190            let view_id = self.parent_view_id();
2191            self.window.next_frame.requested_input_handler = Some(RequestedInputHandler {
2192                view_id,
2193                handler: Some(Box::new(input_handler)),
2194            })
2195        }
2196    }
2197
2198    /// Register a callback that can interrupt the closing of the current window based the returned boolean.
2199    /// If the callback returns false, the window won't be closed.
2200    pub fn on_window_should_close(&mut self, f: impl Fn(&mut WindowContext) -> bool + 'static) {
2201        let mut this = self.to_async();
2202        self.window
2203            .platform_window
2204            .on_should_close(Box::new(move || {
2205                this.update(|_, cx| {
2206                    // Ensure that the window is removed from the app if it's been closed
2207                    // by always pre-empting the system close event.
2208                    if f(cx) {
2209                        cx.remove_window();
2210                    }
2211                    false
2212                })
2213                .unwrap_or(true)
2214            }))
2215    }
2216}
2217
2218impl Context for WindowContext<'_> {
2219    type Result<T> = T;
2220
2221    fn new_model<T>(&mut self, build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T) -> Model<T>
2222    where
2223        T: 'static,
2224    {
2225        let slot = self.app.entities.reserve();
2226        let model = build_model(&mut ModelContext::new(&mut *self.app, slot.downgrade()));
2227        self.entities.insert(slot, model)
2228    }
2229
2230    fn update_model<T: 'static, R>(
2231        &mut self,
2232        model: &Model<T>,
2233        update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
2234    ) -> R {
2235        let mut entity = self.entities.lease(model);
2236        let result = update(
2237            &mut *entity,
2238            &mut ModelContext::new(&mut *self.app, model.downgrade()),
2239        );
2240        self.entities.end_lease(entity);
2241        result
2242    }
2243
2244    fn update_window<T, F>(&mut self, window: AnyWindowHandle, update: F) -> Result<T>
2245    where
2246        F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
2247    {
2248        if window == self.window.handle {
2249            let root_view = self.window.root_view.clone().unwrap();
2250            Ok(update(root_view, self))
2251        } else {
2252            window.update(self.app, update)
2253        }
2254    }
2255
2256    fn read_model<T, R>(
2257        &self,
2258        handle: &Model<T>,
2259        read: impl FnOnce(&T, &AppContext) -> R,
2260    ) -> Self::Result<R>
2261    where
2262        T: 'static,
2263    {
2264        let entity = self.entities.read(handle);
2265        read(entity, &*self.app)
2266    }
2267
2268    fn read_window<T, R>(
2269        &self,
2270        window: &WindowHandle<T>,
2271        read: impl FnOnce(View<T>, &AppContext) -> R,
2272    ) -> Result<R>
2273    where
2274        T: 'static,
2275    {
2276        if window.any_handle == self.window.handle {
2277            let root_view = self
2278                .window
2279                .root_view
2280                .clone()
2281                .unwrap()
2282                .downcast::<T>()
2283                .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
2284            Ok(read(root_view, self))
2285        } else {
2286            self.app.read_window(window, read)
2287        }
2288    }
2289}
2290
2291impl VisualContext for WindowContext<'_> {
2292    fn new_view<V>(
2293        &mut self,
2294        build_view_state: impl FnOnce(&mut ViewContext<'_, V>) -> V,
2295    ) -> Self::Result<View<V>>
2296    where
2297        V: 'static + Render,
2298    {
2299        let slot = self.app.entities.reserve();
2300        let view = View {
2301            model: slot.clone(),
2302        };
2303        let mut cx = ViewContext::new(&mut *self.app, &mut *self.window, &view);
2304        let entity = build_view_state(&mut cx);
2305        cx.entities.insert(slot, entity);
2306
2307        cx.new_view_observers
2308            .clone()
2309            .retain(&TypeId::of::<V>(), |observer| {
2310                let any_view = AnyView::from(view.clone());
2311                (observer)(any_view, self);
2312                true
2313            });
2314
2315        view
2316    }
2317
2318    /// Update the given view. Prefer calling `View::update` instead, which calls this method.
2319    fn update_view<T: 'static, R>(
2320        &mut self,
2321        view: &View<T>,
2322        update: impl FnOnce(&mut T, &mut ViewContext<'_, T>) -> R,
2323    ) -> Self::Result<R> {
2324        let mut lease = self.app.entities.lease(&view.model);
2325        let mut cx = ViewContext::new(&mut *self.app, &mut *self.window, view);
2326        let result = update(&mut *lease, &mut cx);
2327        cx.app.entities.end_lease(lease);
2328        result
2329    }
2330
2331    fn replace_root_view<V>(
2332        &mut self,
2333        build_view: impl FnOnce(&mut ViewContext<'_, V>) -> V,
2334    ) -> Self::Result<View<V>>
2335    where
2336        V: 'static + Render,
2337    {
2338        let view = self.new_view(build_view);
2339        self.window.root_view = Some(view.clone().into());
2340        self.refresh();
2341        view
2342    }
2343
2344    fn focus_view<V: crate::FocusableView>(&mut self, view: &View<V>) -> Self::Result<()> {
2345        self.update_view(view, |view, cx| {
2346            view.focus_handle(cx).clone().focus(cx);
2347        })
2348    }
2349
2350    fn dismiss_view<V>(&mut self, view: &View<V>) -> Self::Result<()>
2351    where
2352        V: ManagedView,
2353    {
2354        self.update_view(view, |_, cx| cx.emit(DismissEvent))
2355    }
2356}
2357
2358impl<'a> std::ops::Deref for WindowContext<'a> {
2359    type Target = AppContext;
2360
2361    fn deref(&self) -> &Self::Target {
2362        self.app
2363    }
2364}
2365
2366impl<'a> std::ops::DerefMut for WindowContext<'a> {
2367    fn deref_mut(&mut self) -> &mut Self::Target {
2368        self.app
2369    }
2370}
2371
2372impl<'a> Borrow<AppContext> for WindowContext<'a> {
2373    fn borrow(&self) -> &AppContext {
2374        self.app
2375    }
2376}
2377
2378impl<'a> BorrowMut<AppContext> for WindowContext<'a> {
2379    fn borrow_mut(&mut self) -> &mut AppContext {
2380        self.app
2381    }
2382}
2383
2384/// This trait contains functionality that is shared across [`ViewContext`] and [`WindowContext`]
2385pub trait BorrowWindow: BorrowMut<Window> + BorrowMut<AppContext> {
2386    #[doc(hidden)]
2387    fn app_mut(&mut self) -> &mut AppContext {
2388        self.borrow_mut()
2389    }
2390
2391    #[doc(hidden)]
2392    fn app(&self) -> &AppContext {
2393        self.borrow()
2394    }
2395
2396    #[doc(hidden)]
2397    fn window(&self) -> &Window {
2398        self.borrow()
2399    }
2400
2401    #[doc(hidden)]
2402    fn window_mut(&mut self) -> &mut Window {
2403        self.borrow_mut()
2404    }
2405
2406    /// Pushes the given element id onto the global stack and invokes the given closure
2407    /// with a `GlobalElementId`, which disambiguates the given id in the context of its ancestor
2408    /// ids. Because elements are discarded and recreated on each frame, the `GlobalElementId` is
2409    /// used to associate state with identified elements across separate frames.
2410    fn with_element_id<R>(
2411        &mut self,
2412        id: Option<impl Into<ElementId>>,
2413        f: impl FnOnce(&mut Self) -> R,
2414    ) -> R {
2415        if let Some(id) = id.map(Into::into) {
2416            let window = self.window_mut();
2417            window.element_id_stack.push(id);
2418            let result = f(self);
2419            let window: &mut Window = self.borrow_mut();
2420            window.element_id_stack.pop();
2421            result
2422        } else {
2423            f(self)
2424        }
2425    }
2426
2427    /// Invoke the given function with the given content mask after intersecting it
2428    /// with the current mask.
2429    fn with_content_mask<R>(
2430        &mut self,
2431        mask: Option<ContentMask<Pixels>>,
2432        f: impl FnOnce(&mut Self) -> R,
2433    ) -> R {
2434        if let Some(mask) = mask {
2435            let mask = mask.intersect(&self.content_mask());
2436            self.window_mut().next_frame.content_mask_stack.push(mask);
2437            let result = f(self);
2438            self.window_mut().next_frame.content_mask_stack.pop();
2439            result
2440        } else {
2441            f(self)
2442        }
2443    }
2444
2445    /// Invoke the given function with the content mask reset to that
2446    /// of the window.
2447    fn break_content_mask<R>(&mut self, f: impl FnOnce(&mut Self) -> R) -> R {
2448        let mask = ContentMask {
2449            bounds: Bounds {
2450                origin: Point::default(),
2451                size: self.window().viewport_size,
2452            },
2453        };
2454        let new_stacking_order_id =
2455            post_inc(&mut self.window_mut().next_frame.next_stacking_order_id);
2456        let new_root_z_index = post_inc(&mut self.window_mut().next_frame.next_root_z_index);
2457        let old_stacking_order = mem::take(&mut self.window_mut().next_frame.z_index_stack);
2458        self.window_mut().next_frame.z_index_stack.id = new_stacking_order_id;
2459        self.window_mut()
2460            .next_frame
2461            .z_index_stack
2462            .push(new_root_z_index);
2463        self.window_mut().next_frame.content_mask_stack.push(mask);
2464        let result = f(self);
2465        self.window_mut().next_frame.content_mask_stack.pop();
2466        self.window_mut().next_frame.z_index_stack = old_stacking_order;
2467        result
2468    }
2469
2470    /// Called during painting to invoke the given closure in a new stacking context. The given
2471    /// z-index is interpreted relative to the previous call to `stack`.
2472    fn with_z_index<R>(&mut self, z_index: u8, f: impl FnOnce(&mut Self) -> R) -> R {
2473        let new_stacking_order_id =
2474            post_inc(&mut self.window_mut().next_frame.next_stacking_order_id);
2475        let old_stacking_order_id = mem::replace(
2476            &mut self.window_mut().next_frame.z_index_stack.id,
2477            new_stacking_order_id,
2478        );
2479        self.window_mut().next_frame.z_index_stack.id = new_stacking_order_id;
2480        self.window_mut().next_frame.z_index_stack.push(z_index);
2481        let result = f(self);
2482        self.window_mut().next_frame.z_index_stack.id = old_stacking_order_id;
2483        self.window_mut().next_frame.z_index_stack.pop();
2484        result
2485    }
2486
2487    /// Update the global element offset relative to the current offset. This is used to implement
2488    /// scrolling.
2489    fn with_element_offset<R>(
2490        &mut self,
2491        offset: Point<Pixels>,
2492        f: impl FnOnce(&mut Self) -> R,
2493    ) -> R {
2494        if offset.is_zero() {
2495            return f(self);
2496        };
2497
2498        let abs_offset = self.element_offset() + offset;
2499        self.with_absolute_element_offset(abs_offset, f)
2500    }
2501
2502    /// Update the global element offset based on the given offset. This is used to implement
2503    /// drag handles and other manual painting of elements.
2504    fn with_absolute_element_offset<R>(
2505        &mut self,
2506        offset: Point<Pixels>,
2507        f: impl FnOnce(&mut Self) -> R,
2508    ) -> R {
2509        self.window_mut()
2510            .next_frame
2511            .element_offset_stack
2512            .push(offset);
2513        let result = f(self);
2514        self.window_mut().next_frame.element_offset_stack.pop();
2515        result
2516    }
2517
2518    /// Obtain the current element offset.
2519    fn element_offset(&self) -> Point<Pixels> {
2520        self.window()
2521            .next_frame
2522            .element_offset_stack
2523            .last()
2524            .copied()
2525            .unwrap_or_default()
2526    }
2527
2528    /// Obtain the current content mask.
2529    fn content_mask(&self) -> ContentMask<Pixels> {
2530        self.window()
2531            .next_frame
2532            .content_mask_stack
2533            .last()
2534            .cloned()
2535            .unwrap_or_else(|| ContentMask {
2536                bounds: Bounds {
2537                    origin: Point::default(),
2538                    size: self.window().viewport_size,
2539                },
2540            })
2541    }
2542
2543    /// The size of an em for the base font of the application. Adjusting this value allows the
2544    /// UI to scale, just like zooming a web page.
2545    fn rem_size(&self) -> Pixels {
2546        self.window().rem_size
2547    }
2548}
2549
2550impl Borrow<Window> for WindowContext<'_> {
2551    fn borrow(&self) -> &Window {
2552        self.window
2553    }
2554}
2555
2556impl BorrowMut<Window> for WindowContext<'_> {
2557    fn borrow_mut(&mut self) -> &mut Window {
2558        self.window
2559    }
2560}
2561
2562impl<T> BorrowWindow for T where T: BorrowMut<AppContext> + BorrowMut<Window> {}
2563
2564/// Provides access to application state that is specialized for a particular [`View`].
2565/// Allows you to interact with focus, emit events, etc.
2566/// ViewContext also derefs to [`WindowContext`], giving you access to all of its methods as well.
2567/// When you call [`View::update`], you're passed a `&mut V` and an `&mut ViewContext<V>`.
2568pub struct ViewContext<'a, V> {
2569    window_cx: WindowContext<'a>,
2570    view: &'a View<V>,
2571}
2572
2573impl<V> Borrow<AppContext> for ViewContext<'_, V> {
2574    fn borrow(&self) -> &AppContext {
2575        &*self.window_cx.app
2576    }
2577}
2578
2579impl<V> BorrowMut<AppContext> for ViewContext<'_, V> {
2580    fn borrow_mut(&mut self) -> &mut AppContext {
2581        &mut *self.window_cx.app
2582    }
2583}
2584
2585impl<V> Borrow<Window> for ViewContext<'_, V> {
2586    fn borrow(&self) -> &Window {
2587        &*self.window_cx.window
2588    }
2589}
2590
2591impl<V> BorrowMut<Window> for ViewContext<'_, V> {
2592    fn borrow_mut(&mut self) -> &mut Window {
2593        &mut *self.window_cx.window
2594    }
2595}
2596
2597impl<'a, V: 'static> ViewContext<'a, V> {
2598    pub(crate) fn new(app: &'a mut AppContext, window: &'a mut Window, view: &'a View<V>) -> Self {
2599        Self {
2600            window_cx: WindowContext::new(app, window),
2601            view,
2602        }
2603    }
2604
2605    /// Get the entity_id of this view.
2606    pub fn entity_id(&self) -> EntityId {
2607        self.view.entity_id()
2608    }
2609
2610    /// Get the view pointer underlying this context.
2611    pub fn view(&self) -> &View<V> {
2612        self.view
2613    }
2614
2615    /// Get the model underlying this view.
2616    pub fn model(&self) -> &Model<V> {
2617        &self.view.model
2618    }
2619
2620    /// Access the underlying window context.
2621    pub fn window_context(&mut self) -> &mut WindowContext<'a> {
2622        &mut self.window_cx
2623    }
2624
2625    /// Set a given callback to be run on the next frame.
2626    pub fn on_next_frame(&mut self, f: impl FnOnce(&mut V, &mut ViewContext<V>) + 'static)
2627    where
2628        V: 'static,
2629    {
2630        let view = self.view().clone();
2631        self.window_cx.on_next_frame(move |cx| view.update(cx, f));
2632    }
2633
2634    /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
2635    /// that are currently on the stack to be returned to the app.
2636    pub fn defer(&mut self, f: impl FnOnce(&mut V, &mut ViewContext<V>) + 'static) {
2637        let view = self.view().downgrade();
2638        self.window_cx.defer(move |cx| {
2639            view.update(cx, f).ok();
2640        });
2641    }
2642
2643    /// Observe another model or view for changes to its state, as tracked by [`ModelContext::notify`].
2644    pub fn observe<V2, E>(
2645        &mut self,
2646        entity: &E,
2647        mut on_notify: impl FnMut(&mut V, E, &mut ViewContext<'_, V>) + 'static,
2648    ) -> Subscription
2649    where
2650        V2: 'static,
2651        V: 'static,
2652        E: Entity<V2>,
2653    {
2654        let view = self.view().downgrade();
2655        let entity_id = entity.entity_id();
2656        let entity = entity.downgrade();
2657        let window_handle = self.window.handle;
2658        let (subscription, activate) = self.app.observers.insert(
2659            entity_id,
2660            Box::new(move |cx| {
2661                window_handle
2662                    .update(cx, |_, cx| {
2663                        if let Some(handle) = E::upgrade_from(&entity) {
2664                            view.update(cx, |this, cx| on_notify(this, handle, cx))
2665                                .is_ok()
2666                        } else {
2667                            false
2668                        }
2669                    })
2670                    .unwrap_or(false)
2671            }),
2672        );
2673        self.app.defer(move |_| activate());
2674        subscription
2675    }
2676
2677    /// Subscribe to events emitted by another model or view.
2678    /// The entity to which you're subscribing must implement the [`EventEmitter`] trait.
2679    /// 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.
2680    pub fn subscribe<V2, E, Evt>(
2681        &mut self,
2682        entity: &E,
2683        mut on_event: impl FnMut(&mut V, E, &Evt, &mut ViewContext<'_, V>) + 'static,
2684    ) -> Subscription
2685    where
2686        V2: EventEmitter<Evt>,
2687        E: Entity<V2>,
2688        Evt: 'static,
2689    {
2690        let view = self.view().downgrade();
2691        let entity_id = entity.entity_id();
2692        let handle = entity.downgrade();
2693        let window_handle = self.window.handle;
2694        let (subscription, activate) = self.app.event_listeners.insert(
2695            entity_id,
2696            (
2697                TypeId::of::<Evt>(),
2698                Box::new(move |event, cx| {
2699                    window_handle
2700                        .update(cx, |_, cx| {
2701                            if let Some(handle) = E::upgrade_from(&handle) {
2702                                let event = event.downcast_ref().expect("invalid event type");
2703                                view.update(cx, |this, cx| on_event(this, handle, event, cx))
2704                                    .is_ok()
2705                            } else {
2706                                false
2707                            }
2708                        })
2709                        .unwrap_or(false)
2710                }),
2711            ),
2712        );
2713        self.app.defer(move |_| activate());
2714        subscription
2715    }
2716
2717    /// Register a callback to be invoked when the view is released.
2718    ///
2719    /// The callback receives a handle to the view's window. This handle may be
2720    /// invalid, if the window was closed before the view was released.
2721    pub fn on_release(
2722        &mut self,
2723        on_release: impl FnOnce(&mut V, AnyWindowHandle, &mut AppContext) + 'static,
2724    ) -> Subscription {
2725        let window_handle = self.window.handle;
2726        let (subscription, activate) = self.app.release_listeners.insert(
2727            self.view.model.entity_id,
2728            Box::new(move |this, cx| {
2729                let this = this.downcast_mut().expect("invalid entity type");
2730                on_release(this, window_handle, cx)
2731            }),
2732        );
2733        activate();
2734        subscription
2735    }
2736
2737    /// Register a callback to be invoked when the given Model or View is released.
2738    pub fn observe_release<V2, E>(
2739        &mut self,
2740        entity: &E,
2741        mut on_release: impl FnMut(&mut V, &mut V2, &mut ViewContext<'_, V>) + 'static,
2742    ) -> Subscription
2743    where
2744        V: 'static,
2745        V2: 'static,
2746        E: Entity<V2>,
2747    {
2748        let view = self.view().downgrade();
2749        let entity_id = entity.entity_id();
2750        let window_handle = self.window.handle;
2751        let (subscription, activate) = self.app.release_listeners.insert(
2752            entity_id,
2753            Box::new(move |entity, cx| {
2754                let entity = entity.downcast_mut().expect("invalid entity type");
2755                let _ = window_handle.update(cx, |_, cx| {
2756                    view.update(cx, |this, cx| on_release(this, entity, cx))
2757                });
2758            }),
2759        );
2760        activate();
2761        subscription
2762    }
2763
2764    /// Indicate that this view has changed, which will invoke any observers and also mark the window as dirty.
2765    /// If this view or any of its ancestors are *cached*, notifying it will cause it or its ancestors to be redrawn.
2766    pub fn notify(&mut self) {
2767        for view_id in self
2768            .window
2769            .rendered_frame
2770            .dispatch_tree
2771            .view_path(self.view.entity_id())
2772            .into_iter()
2773            .rev()
2774        {
2775            if !self.window.dirty_views.insert(view_id) {
2776                break;
2777            }
2778        }
2779
2780        if !self.window.drawing {
2781            self.window_cx.window.dirty = true;
2782            self.window_cx.app.push_effect(Effect::Notify {
2783                emitter: self.view.model.entity_id,
2784            });
2785        }
2786    }
2787
2788    /// Register a callback to be invoked when the window is resized.
2789    pub fn observe_window_bounds(
2790        &mut self,
2791        mut callback: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2792    ) -> Subscription {
2793        let view = self.view.downgrade();
2794        let (subscription, activate) = self.window.bounds_observers.insert(
2795            (),
2796            Box::new(move |cx| view.update(cx, |view, cx| callback(view, cx)).is_ok()),
2797        );
2798        activate();
2799        subscription
2800    }
2801
2802    /// Register a callback to be invoked when the window is activated or deactivated.
2803    pub fn observe_window_activation(
2804        &mut self,
2805        mut callback: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2806    ) -> Subscription {
2807        let view = self.view.downgrade();
2808        let (subscription, activate) = self.window.activation_observers.insert(
2809            (),
2810            Box::new(move |cx| view.update(cx, |view, cx| callback(view, cx)).is_ok()),
2811        );
2812        activate();
2813        subscription
2814    }
2815
2816    /// Register a listener to be called when the given focus handle receives focus.
2817    /// Returns a subscription and persists until the subscription is dropped.
2818    pub fn on_focus(
2819        &mut self,
2820        handle: &FocusHandle,
2821        mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2822    ) -> Subscription {
2823        let view = self.view.downgrade();
2824        let focus_id = handle.id;
2825        let (subscription, activate) = self.window.focus_listeners.insert(
2826            (),
2827            Box::new(move |event, cx| {
2828                view.update(cx, |view, cx| {
2829                    if event.previous_focus_path.last() != Some(&focus_id)
2830                        && event.current_focus_path.last() == Some(&focus_id)
2831                    {
2832                        listener(view, cx)
2833                    }
2834                })
2835                .is_ok()
2836            }),
2837        );
2838        self.app.defer(move |_| activate());
2839        subscription
2840    }
2841
2842    /// Register a listener to be called when the given focus handle or one of its descendants receives focus.
2843    /// Returns a subscription and persists until the subscription is dropped.
2844    pub fn on_focus_in(
2845        &mut self,
2846        handle: &FocusHandle,
2847        mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2848    ) -> Subscription {
2849        let view = self.view.downgrade();
2850        let focus_id = handle.id;
2851        let (subscription, activate) = self.window.focus_listeners.insert(
2852            (),
2853            Box::new(move |event, cx| {
2854                view.update(cx, |view, cx| {
2855                    if !event.previous_focus_path.contains(&focus_id)
2856                        && event.current_focus_path.contains(&focus_id)
2857                    {
2858                        listener(view, cx)
2859                    }
2860                })
2861                .is_ok()
2862            }),
2863        );
2864        self.app.defer(move |_| activate());
2865        subscription
2866    }
2867
2868    /// Register a listener to be called when the given focus handle loses focus.
2869    /// Returns a subscription and persists until the subscription is dropped.
2870    pub fn on_blur(
2871        &mut self,
2872        handle: &FocusHandle,
2873        mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2874    ) -> Subscription {
2875        let view = self.view.downgrade();
2876        let focus_id = handle.id;
2877        let (subscription, activate) = self.window.focus_listeners.insert(
2878            (),
2879            Box::new(move |event, cx| {
2880                view.update(cx, |view, cx| {
2881                    if event.previous_focus_path.last() == Some(&focus_id)
2882                        && event.current_focus_path.last() != Some(&focus_id)
2883                    {
2884                        listener(view, cx)
2885                    }
2886                })
2887                .is_ok()
2888            }),
2889        );
2890        self.app.defer(move |_| activate());
2891        subscription
2892    }
2893
2894    /// Register a listener to be called when nothing in the window has focus.
2895    /// This typically happens when the node that was focused is removed from the tree,
2896    /// and this callback lets you chose a default place to restore the users focus.
2897    /// Returns a subscription and persists until the subscription is dropped.
2898    pub fn on_focus_lost(
2899        &mut self,
2900        mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2901    ) -> Subscription {
2902        let view = self.view.downgrade();
2903        let (subscription, activate) = self.window.focus_lost_listeners.insert(
2904            (),
2905            Box::new(move |cx| view.update(cx, |view, cx| listener(view, cx)).is_ok()),
2906        );
2907        activate();
2908        subscription
2909    }
2910
2911    /// Register a listener to be called when the given focus handle or one of its descendants loses focus.
2912    /// Returns a subscription and persists until the subscription is dropped.
2913    pub fn on_focus_out(
2914        &mut self,
2915        handle: &FocusHandle,
2916        mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2917    ) -> Subscription {
2918        let view = self.view.downgrade();
2919        let focus_id = handle.id;
2920        let (subscription, activate) = self.window.focus_listeners.insert(
2921            (),
2922            Box::new(move |event, cx| {
2923                view.update(cx, |view, cx| {
2924                    if event.previous_focus_path.contains(&focus_id)
2925                        && !event.current_focus_path.contains(&focus_id)
2926                    {
2927                        listener(view, cx)
2928                    }
2929                })
2930                .is_ok()
2931            }),
2932        );
2933        self.app.defer(move |_| activate());
2934        subscription
2935    }
2936
2937    /// Schedule a future to be run asynchronously.
2938    /// The given callback is invoked with a [`WeakView<V>`] to avoid leaking the view for a long-running process.
2939    /// It's also given an [`AsyncWindowContext`], which can be used to access the state of the view across await points.
2940    /// The returned future will be polled on the main thread.
2941    pub fn spawn<Fut, R>(
2942        &mut self,
2943        f: impl FnOnce(WeakView<V>, AsyncWindowContext) -> Fut,
2944    ) -> Task<R>
2945    where
2946        R: 'static,
2947        Fut: Future<Output = R> + 'static,
2948    {
2949        let view = self.view().downgrade();
2950        self.window_cx.spawn(|cx| f(view, cx))
2951    }
2952
2953    /// Update the global state of the given type.
2954    pub fn update_global<G, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R
2955    where
2956        G: 'static,
2957    {
2958        let mut global = self.app.lease_global::<G>();
2959        let result = f(&mut global, self);
2960        self.app.end_global_lease(global);
2961        result
2962    }
2963
2964    /// Register a callback to be invoked when the given global state changes.
2965    pub fn observe_global<G: 'static>(
2966        &mut self,
2967        mut f: impl FnMut(&mut V, &mut ViewContext<'_, V>) + 'static,
2968    ) -> Subscription {
2969        let window_handle = self.window.handle;
2970        let view = self.view().downgrade();
2971        let (subscription, activate) = self.global_observers.insert(
2972            TypeId::of::<G>(),
2973            Box::new(move |cx| {
2974                window_handle
2975                    .update(cx, |_, cx| view.update(cx, |view, cx| f(view, cx)).is_ok())
2976                    .unwrap_or(false)
2977            }),
2978        );
2979        self.app.defer(move |_| activate());
2980        subscription
2981    }
2982
2983    /// Add a listener for any mouse event that occurs in the window.
2984    /// This is a fairly low level method.
2985    /// Typically, you'll want to use methods on UI elements, which perform bounds checking etc.
2986    pub fn on_mouse_event<Event: 'static>(
2987        &mut self,
2988        handler: impl Fn(&mut V, &Event, DispatchPhase, &mut ViewContext<V>) + 'static,
2989    ) {
2990        let handle = self.view().clone();
2991        self.window_cx.on_mouse_event(move |event, phase, cx| {
2992            handle.update(cx, |view, cx| {
2993                handler(view, event, phase, cx);
2994            })
2995        });
2996    }
2997
2998    /// Register a callback to be invoked when the given Key Event is dispatched to the window.
2999    pub fn on_key_event<Event: 'static>(
3000        &mut self,
3001        handler: impl Fn(&mut V, &Event, DispatchPhase, &mut ViewContext<V>) + 'static,
3002    ) {
3003        let handle = self.view().clone();
3004        self.window_cx.on_key_event(move |event, phase, cx| {
3005            handle.update(cx, |view, cx| {
3006                handler(view, event, phase, cx);
3007            })
3008        });
3009    }
3010
3011    /// Register a callback to be invoked when the given Action type is dispatched to the window.
3012    pub fn on_action(
3013        &mut self,
3014        action_type: TypeId,
3015        listener: impl Fn(&mut V, &dyn Any, DispatchPhase, &mut ViewContext<V>) + 'static,
3016    ) {
3017        let handle = self.view().clone();
3018        self.window_cx
3019            .on_action(action_type, move |action, phase, cx| {
3020                handle.update(cx, |view, cx| {
3021                    listener(view, action, phase, cx);
3022                })
3023            });
3024    }
3025
3026    /// Emit an event to be handled any other views that have subscribed via [ViewContext::subscribe].
3027    pub fn emit<Evt>(&mut self, event: Evt)
3028    where
3029        Evt: 'static,
3030        V: EventEmitter<Evt>,
3031    {
3032        let emitter = self.view.model.entity_id;
3033        self.app.push_effect(Effect::Emit {
3034            emitter,
3035            event_type: TypeId::of::<Evt>(),
3036            event: Box::new(event),
3037        });
3038    }
3039
3040    /// Move focus to the current view, assuming it implements [`FocusableView`].
3041    pub fn focus_self(&mut self)
3042    where
3043        V: FocusableView,
3044    {
3045        self.defer(|view, cx| view.focus_handle(cx).focus(cx))
3046    }
3047
3048    /// Convenience method for accessing view state in an event callback.
3049    ///
3050    /// Many GPUI callbacks take the form of `Fn(&E, &mut WindowContext)`,
3051    /// but it's often useful to be able to access view state in these
3052    /// callbacks. This method provides a convenient way to do so.
3053    pub fn listener<E>(
3054        &self,
3055        f: impl Fn(&mut V, &E, &mut ViewContext<V>) + 'static,
3056    ) -> impl Fn(&E, &mut WindowContext) + 'static {
3057        let view = self.view().downgrade();
3058        move |e: &E, cx: &mut WindowContext| {
3059            view.update(cx, |view, cx| f(view, e, cx)).ok();
3060        }
3061    }
3062}
3063
3064impl<V> Context for ViewContext<'_, V> {
3065    type Result<U> = U;
3066
3067    fn new_model<T: 'static>(
3068        &mut self,
3069        build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
3070    ) -> Model<T> {
3071        self.window_cx.new_model(build_model)
3072    }
3073
3074    fn update_model<T: 'static, R>(
3075        &mut self,
3076        model: &Model<T>,
3077        update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
3078    ) -> R {
3079        self.window_cx.update_model(model, update)
3080    }
3081
3082    fn update_window<T, F>(&mut self, window: AnyWindowHandle, update: F) -> Result<T>
3083    where
3084        F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
3085    {
3086        self.window_cx.update_window(window, update)
3087    }
3088
3089    fn read_model<T, R>(
3090        &self,
3091        handle: &Model<T>,
3092        read: impl FnOnce(&T, &AppContext) -> R,
3093    ) -> Self::Result<R>
3094    where
3095        T: 'static,
3096    {
3097        self.window_cx.read_model(handle, read)
3098    }
3099
3100    fn read_window<T, R>(
3101        &self,
3102        window: &WindowHandle<T>,
3103        read: impl FnOnce(View<T>, &AppContext) -> R,
3104    ) -> Result<R>
3105    where
3106        T: 'static,
3107    {
3108        self.window_cx.read_window(window, read)
3109    }
3110}
3111
3112impl<V: 'static> VisualContext for ViewContext<'_, V> {
3113    fn new_view<W: Render + 'static>(
3114        &mut self,
3115        build_view_state: impl FnOnce(&mut ViewContext<'_, W>) -> W,
3116    ) -> Self::Result<View<W>> {
3117        self.window_cx.new_view(build_view_state)
3118    }
3119
3120    fn update_view<V2: 'static, R>(
3121        &mut self,
3122        view: &View<V2>,
3123        update: impl FnOnce(&mut V2, &mut ViewContext<'_, V2>) -> R,
3124    ) -> Self::Result<R> {
3125        self.window_cx.update_view(view, update)
3126    }
3127
3128    fn replace_root_view<W>(
3129        &mut self,
3130        build_view: impl FnOnce(&mut ViewContext<'_, W>) -> W,
3131    ) -> Self::Result<View<W>>
3132    where
3133        W: 'static + Render,
3134    {
3135        self.window_cx.replace_root_view(build_view)
3136    }
3137
3138    fn focus_view<W: FocusableView>(&mut self, view: &View<W>) -> Self::Result<()> {
3139        self.window_cx.focus_view(view)
3140    }
3141
3142    fn dismiss_view<W: ManagedView>(&mut self, view: &View<W>) -> Self::Result<()> {
3143        self.window_cx.dismiss_view(view)
3144    }
3145}
3146
3147impl<'a, V> std::ops::Deref for ViewContext<'a, V> {
3148    type Target = WindowContext<'a>;
3149
3150    fn deref(&self) -> &Self::Target {
3151        &self.window_cx
3152    }
3153}
3154
3155impl<'a, V> std::ops::DerefMut for ViewContext<'a, V> {
3156    fn deref_mut(&mut self) -> &mut Self::Target {
3157        &mut self.window_cx
3158    }
3159}
3160
3161// #[derive(Clone, Copy, Eq, PartialEq, Hash)]
3162slotmap::new_key_type! {
3163    /// A unique identifier for a window.
3164    pub struct WindowId;
3165}
3166
3167impl WindowId {
3168    /// Converts this window ID to a `u64`.
3169    pub fn as_u64(&self) -> u64 {
3170        self.0.as_ffi()
3171    }
3172}
3173
3174/// A handle to a window with a specific root view type.
3175/// Note that this does not keep the window alive on its own.
3176#[derive(Deref, DerefMut)]
3177pub struct WindowHandle<V> {
3178    #[deref]
3179    #[deref_mut]
3180    pub(crate) any_handle: AnyWindowHandle,
3181    state_type: PhantomData<V>,
3182}
3183
3184impl<V: 'static + Render> WindowHandle<V> {
3185    /// Create a new handle from a window ID.
3186    /// This does not check if the root type of the window is `V`.
3187    pub fn new(id: WindowId) -> Self {
3188        WindowHandle {
3189            any_handle: AnyWindowHandle {
3190                id,
3191                state_type: TypeId::of::<V>(),
3192            },
3193            state_type: PhantomData,
3194        }
3195    }
3196
3197    /// Get the root view out of this window.
3198    ///
3199    /// This will fail if the window is closed or if the root view's type does not match `V`.
3200    pub fn root<C>(&self, cx: &mut C) -> Result<View<V>>
3201    where
3202        C: Context,
3203    {
3204        Flatten::flatten(cx.update_window(self.any_handle, |root_view, _| {
3205            root_view
3206                .downcast::<V>()
3207                .map_err(|_| anyhow!("the type of the window's root view has changed"))
3208        }))
3209    }
3210
3211    /// Update the root view of this window.
3212    ///
3213    /// This will fail if the window has been closed or if the root view's type does not match
3214    pub fn update<C, R>(
3215        &self,
3216        cx: &mut C,
3217        update: impl FnOnce(&mut V, &mut ViewContext<'_, V>) -> R,
3218    ) -> Result<R>
3219    where
3220        C: Context,
3221    {
3222        cx.update_window(self.any_handle, |root_view, cx| {
3223            let view = root_view
3224                .downcast::<V>()
3225                .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
3226            Ok(cx.update_view(&view, update))
3227        })?
3228    }
3229
3230    /// Read the root view out of this window.
3231    ///
3232    /// This will fail if the window is closed or if the root view's type does not match `V`.
3233    pub fn read<'a>(&self, cx: &'a AppContext) -> Result<&'a V> {
3234        let x = cx
3235            .windows
3236            .get(self.id)
3237            .and_then(|window| {
3238                window
3239                    .as_ref()
3240                    .and_then(|window| window.root_view.clone())
3241                    .map(|root_view| root_view.downcast::<V>())
3242            })
3243            .ok_or_else(|| anyhow!("window not found"))?
3244            .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
3245
3246        Ok(x.read(cx))
3247    }
3248
3249    /// Read the root view out of this window, with a callback
3250    ///
3251    /// This will fail if the window is closed or if the root view's type does not match `V`.
3252    pub fn read_with<C, R>(&self, cx: &C, read_with: impl FnOnce(&V, &AppContext) -> R) -> Result<R>
3253    where
3254        C: Context,
3255    {
3256        cx.read_window(self, |root_view, cx| read_with(root_view.read(cx), cx))
3257    }
3258
3259    /// Read the root view pointer off of this window.
3260    ///
3261    /// This will fail if the window is closed or if the root view's type does not match `V`.
3262    pub fn root_view<C>(&self, cx: &C) -> Result<View<V>>
3263    where
3264        C: Context,
3265    {
3266        cx.read_window(self, |root_view, _cx| root_view.clone())
3267    }
3268
3269    /// Check if this window is 'active'.
3270    ///
3271    /// Will return `None` if the window is closed.
3272    pub fn is_active(&self, cx: &AppContext) -> Option<bool> {
3273        cx.windows
3274            .get(self.id)
3275            .and_then(|window| window.as_ref().map(|window| window.active))
3276    }
3277}
3278
3279impl<V> Copy for WindowHandle<V> {}
3280
3281impl<V> Clone for WindowHandle<V> {
3282    fn clone(&self) -> Self {
3283        *self
3284    }
3285}
3286
3287impl<V> PartialEq for WindowHandle<V> {
3288    fn eq(&self, other: &Self) -> bool {
3289        self.any_handle == other.any_handle
3290    }
3291}
3292
3293impl<V> Eq for WindowHandle<V> {}
3294
3295impl<V> Hash for WindowHandle<V> {
3296    fn hash<H: Hasher>(&self, state: &mut H) {
3297        self.any_handle.hash(state);
3298    }
3299}
3300
3301impl<V: 'static> From<WindowHandle<V>> for AnyWindowHandle {
3302    fn from(val: WindowHandle<V>) -> Self {
3303        val.any_handle
3304    }
3305}
3306
3307/// A handle to a window with any root view type, which can be downcast to a window with a specific root view type.
3308#[derive(Copy, Clone, PartialEq, Eq, Hash)]
3309pub struct AnyWindowHandle {
3310    pub(crate) id: WindowId,
3311    state_type: TypeId,
3312}
3313
3314impl AnyWindowHandle {
3315    /// Get the ID of this window.
3316    pub fn window_id(&self) -> WindowId {
3317        self.id
3318    }
3319
3320    /// Attempt to convert this handle to a window handle with a specific root view type.
3321    /// If the types do not match, this will return `None`.
3322    pub fn downcast<T: 'static>(&self) -> Option<WindowHandle<T>> {
3323        if TypeId::of::<T>() == self.state_type {
3324            Some(WindowHandle {
3325                any_handle: *self,
3326                state_type: PhantomData,
3327            })
3328        } else {
3329            None
3330        }
3331    }
3332
3333    /// Update the state of the root view of this window.
3334    ///
3335    /// This will fail if the window has been closed.
3336    pub fn update<C, R>(
3337        self,
3338        cx: &mut C,
3339        update: impl FnOnce(AnyView, &mut WindowContext<'_>) -> R,
3340    ) -> Result<R>
3341    where
3342        C: Context,
3343    {
3344        cx.update_window(self, update)
3345    }
3346
3347    /// Read the state of the root view of this window.
3348    ///
3349    /// This will fail if the window has been closed.
3350    pub fn read<T, C, R>(self, cx: &C, read: impl FnOnce(View<T>, &AppContext) -> R) -> Result<R>
3351    where
3352        C: Context,
3353        T: 'static,
3354    {
3355        let view = self
3356            .downcast::<T>()
3357            .context("the type of the window's root view has changed")?;
3358
3359        cx.read_window(&view, read)
3360    }
3361}
3362
3363/// An identifier for an [`Element`](crate::Element).
3364///
3365/// Can be constructed with a string, a number, or both, as well
3366/// as other internal representations.
3367#[derive(Clone, Debug, Eq, PartialEq, Hash)]
3368pub enum ElementId {
3369    /// The ID of a View element
3370    View(EntityId),
3371    /// An integer ID.
3372    Integer(usize),
3373    /// A string based ID.
3374    Name(SharedString),
3375    /// An ID that's equated with a focus handle.
3376    FocusHandle(FocusId),
3377    /// A combination of a name and an integer.
3378    NamedInteger(SharedString, usize),
3379}
3380
3381impl ElementId {
3382    pub(crate) fn from_entity_id(entity_id: EntityId) -> Self {
3383        ElementId::View(entity_id)
3384    }
3385}
3386
3387impl TryInto<SharedString> for ElementId {
3388    type Error = anyhow::Error;
3389
3390    fn try_into(self) -> anyhow::Result<SharedString> {
3391        if let ElementId::Name(name) = self {
3392            Ok(name)
3393        } else {
3394            Err(anyhow!("element id is not string"))
3395        }
3396    }
3397}
3398
3399impl From<usize> for ElementId {
3400    fn from(id: usize) -> Self {
3401        ElementId::Integer(id)
3402    }
3403}
3404
3405impl From<i32> for ElementId {
3406    fn from(id: i32) -> Self {
3407        Self::Integer(id as usize)
3408    }
3409}
3410
3411impl From<SharedString> for ElementId {
3412    fn from(name: SharedString) -> Self {
3413        ElementId::Name(name)
3414    }
3415}
3416
3417impl From<&'static str> for ElementId {
3418    fn from(name: &'static str) -> Self {
3419        ElementId::Name(name.into())
3420    }
3421}
3422
3423impl<'a> From<&'a FocusHandle> for ElementId {
3424    fn from(handle: &'a FocusHandle) -> Self {
3425        ElementId::FocusHandle(handle.id)
3426    }
3427}
3428
3429impl From<(&'static str, EntityId)> for ElementId {
3430    fn from((name, id): (&'static str, EntityId)) -> Self {
3431        ElementId::NamedInteger(name.into(), id.as_u64() as usize)
3432    }
3433}
3434
3435impl From<(&'static str, usize)> for ElementId {
3436    fn from((name, id): (&'static str, usize)) -> Self {
3437        ElementId::NamedInteger(name.into(), id)
3438    }
3439}
3440
3441impl From<(&'static str, u64)> for ElementId {
3442    fn from((name, id): (&'static str, u64)) -> Self {
3443        ElementId::NamedInteger(name.into(), id as usize)
3444    }
3445}
3446
3447/// A rectangle to be rendered in the window at the given position and size.
3448/// Passed as an argument [`WindowContext::paint_quad`].
3449#[derive(Clone)]
3450pub struct PaintQuad {
3451    bounds: Bounds<Pixels>,
3452    corner_radii: Corners<Pixels>,
3453    background: Hsla,
3454    border_widths: Edges<Pixels>,
3455    border_color: Hsla,
3456}
3457
3458impl PaintQuad {
3459    /// Set the corner radii of the quad.
3460    pub fn corner_radii(self, corner_radii: impl Into<Corners<Pixels>>) -> Self {
3461        PaintQuad {
3462            corner_radii: corner_radii.into(),
3463            ..self
3464        }
3465    }
3466
3467    /// Set the border widths of the quad.
3468    pub fn border_widths(self, border_widths: impl Into<Edges<Pixels>>) -> Self {
3469        PaintQuad {
3470            border_widths: border_widths.into(),
3471            ..self
3472        }
3473    }
3474
3475    /// Set the border color of the quad.
3476    pub fn border_color(self, border_color: impl Into<Hsla>) -> Self {
3477        PaintQuad {
3478            border_color: border_color.into(),
3479            ..self
3480        }
3481    }
3482
3483    /// Set the background color of the quad.
3484    pub fn background(self, background: impl Into<Hsla>) -> Self {
3485        PaintQuad {
3486            background: background.into(),
3487            ..self
3488        }
3489    }
3490}
3491
3492/// Create a quad with the given parameters.
3493pub fn quad(
3494    bounds: Bounds<Pixels>,
3495    corner_radii: impl Into<Corners<Pixels>>,
3496    background: impl Into<Hsla>,
3497    border_widths: impl Into<Edges<Pixels>>,
3498    border_color: impl Into<Hsla>,
3499) -> PaintQuad {
3500    PaintQuad {
3501        bounds,
3502        corner_radii: corner_radii.into(),
3503        background: background.into(),
3504        border_widths: border_widths.into(),
3505        border_color: border_color.into(),
3506    }
3507}
3508
3509/// Create a filled quad with the given bounds and background color.
3510pub fn fill(bounds: impl Into<Bounds<Pixels>>, background: impl Into<Hsla>) -> PaintQuad {
3511    PaintQuad {
3512        bounds: bounds.into(),
3513        corner_radii: (0.).into(),
3514        background: background.into(),
3515        border_widths: (0.).into(),
3516        border_color: transparent_black(),
3517    }
3518}
3519
3520/// Create a rectangle outline with the given bounds, border color, and a 1px border width
3521pub fn outline(bounds: impl Into<Bounds<Pixels>>, border_color: impl Into<Hsla>) -> PaintQuad {
3522    PaintQuad {
3523        bounds: bounds.into(),
3524        corner_radii: (0.).into(),
3525        background: transparent_black(),
3526        border_widths: (1.).into(),
3527        border_color: border_color.into(),
3528    }
3529}