window.rs

   1use crate::{
   2    hash, point, prelude::*, px, size, transparent_black, Action, AnyDrag, AnyElement, AnyTooltip,
   3    AnyView, AppContext, Arena, Asset, AsyncWindowContext, AvailableSpace, Bounds, BoxShadow,
   4    Context, Corners, CursorStyle, Decorations, DevicePixels, DispatchActionListener,
   5    DispatchNodeId, DispatchTree, DisplayId, Edges, Effect, Entity, EntityId, EventEmitter,
   6    FileDropEvent, Flatten, FontId, GPUSpecs, Global, GlobalElementId, GlyphId, Hsla, ImageData,
   7    InputHandler, IsZero, KeyBinding, KeyContext, KeyDownEvent, KeyEvent, Keystroke,
   8    KeystrokeEvent, LayoutId, LineLayoutIndex, Model, ModelContext, Modifiers,
   9    ModifiersChangedEvent, MonochromeSprite, MouseButton, MouseEvent, MouseMoveEvent, MouseUpEvent,
  10    Path, Pixels, PlatformAtlas, PlatformDisplay, PlatformInput, PlatformInputHandler,
  11    PlatformWindow, Point, PolychromeSprite, PromptLevel, Quad, Render, RenderGlyphParams,
  12    RenderImageParams, RenderSvgParams, Replay, ResizeEdge, ScaledPixels, Scene, Shadow,
  13    SharedString, Size, StrikethroughStyle, Style, SubscriberSet, Subscription, TaffyLayoutEngine,
  14    Task, TextStyle, TextStyleRefinement, TransformationMatrix, Underline, UnderlineStyle, View,
  15    VisualContext, WeakView, WindowAppearance, WindowBackgroundAppearance, WindowBounds,
  16    WindowControls, WindowDecorations, WindowOptions, WindowParams, WindowTextSystem,
  17    SUBPIXEL_VARIANTS,
  18};
  19use anyhow::{anyhow, Context as _, Result};
  20use collections::{FxHashMap, FxHashSet};
  21use derive_more::{Deref, DerefMut};
  22use futures::channel::oneshot;
  23use futures::{future::Shared, FutureExt};
  24#[cfg(target_os = "macos")]
  25use media::core_video::CVImageBuffer;
  26use parking_lot::RwLock;
  27use refineable::Refineable;
  28use slotmap::SlotMap;
  29use smallvec::SmallVec;
  30use std::{
  31    any::{Any, TypeId},
  32    borrow::{Borrow, BorrowMut, Cow},
  33    cell::{Cell, RefCell},
  34    cmp,
  35    fmt::{Debug, Display},
  36    future::Future,
  37    hash::{Hash, Hasher},
  38    marker::PhantomData,
  39    mem,
  40    ops::Range,
  41    rc::Rc,
  42    sync::{
  43        atomic::{AtomicUsize, Ordering::SeqCst},
  44        Arc, Weak,
  45    },
  46    time::{Duration, Instant},
  47};
  48use util::post_inc;
  49use util::{measure, ResultExt};
  50use uuid::Uuid;
  51
  52mod prompts;
  53
  54pub use prompts::*;
  55
  56pub(crate) const DEFAULT_WINDOW_SIZE: Size<Pixels> = size(px(1024.), px(700.));
  57
  58/// Represents the two different phases when dispatching events.
  59#[derive(Default, Copy, Clone, Debug, Eq, PartialEq)]
  60pub enum DispatchPhase {
  61    /// After the capture phase comes the bubble phase, in which mouse event listeners are
  62    /// invoked front to back and keyboard event listeners are invoked from the focused element
  63    /// to the root of the element tree. This is the phase you'll most commonly want to use when
  64    /// registering event listeners.
  65    #[default]
  66    Bubble,
  67    /// During the initial capture phase, mouse event listeners are invoked back to front, and keyboard
  68    /// listeners are invoked from the root of the tree downward toward the focused element. This phase
  69    /// is used for special purposes such as clearing the "pressed" state for click events. If
  70    /// you stop event propagation during this phase, you need to know what you're doing. Handlers
  71    /// outside of the immediate region may rely on detecting non-local events during this phase.
  72    Capture,
  73}
  74
  75impl DispatchPhase {
  76    /// Returns true if this represents the "bubble" phase.
  77    pub fn bubble(self) -> bool {
  78        self == DispatchPhase::Bubble
  79    }
  80
  81    /// Returns true if this represents the "capture" phase.
  82    pub fn capture(self) -> bool {
  83        self == DispatchPhase::Capture
  84    }
  85}
  86
  87type AnyObserver = Box<dyn FnMut(&mut WindowContext) -> bool + 'static>;
  88
  89type AnyWindowFocusListener =
  90    Box<dyn FnMut(&WindowFocusEvent, &mut WindowContext) -> bool + 'static>;
  91
  92struct WindowFocusEvent {
  93    previous_focus_path: SmallVec<[FocusId; 8]>,
  94    current_focus_path: SmallVec<[FocusId; 8]>,
  95}
  96
  97impl WindowFocusEvent {
  98    pub fn is_focus_in(&self, focus_id: FocusId) -> bool {
  99        !self.previous_focus_path.contains(&focus_id) && self.current_focus_path.contains(&focus_id)
 100    }
 101
 102    pub fn is_focus_out(&self, focus_id: FocusId) -> bool {
 103        self.previous_focus_path.contains(&focus_id) && !self.current_focus_path.contains(&focus_id)
 104    }
 105}
 106
 107/// This is provided when subscribing for `ViewContext::on_focus_out` events.
 108pub struct FocusOutEvent {
 109    /// A weak focus handle representing what was blurred.
 110    pub blurred: WeakFocusHandle,
 111}
 112
 113slotmap::new_key_type! {
 114    /// A globally unique identifier for a focusable element.
 115    pub struct FocusId;
 116}
 117
 118thread_local! {
 119    /// 8MB wasn't quite enough...
 120    pub(crate) static ELEMENT_ARENA: RefCell<Arena> = RefCell::new(Arena::new(32 * 1024 * 1024));
 121}
 122
 123impl FocusId {
 124    /// Obtains whether the element associated with this handle is currently focused.
 125    pub fn is_focused(&self, cx: &WindowContext) -> bool {
 126        cx.window.focus == Some(*self)
 127    }
 128
 129    /// Obtains whether the element associated with this handle contains the focused
 130    /// element or is itself focused.
 131    pub fn contains_focused(&self, cx: &WindowContext) -> bool {
 132        cx.focused()
 133            .map_or(false, |focused| self.contains(focused.id, cx))
 134    }
 135
 136    /// Obtains whether the element associated with this handle is contained within the
 137    /// focused element or is itself focused.
 138    pub fn within_focused(&self, cx: &WindowContext) -> bool {
 139        let focused = cx.focused();
 140        focused.map_or(false, |focused| focused.id.contains(*self, cx))
 141    }
 142
 143    /// Obtains whether this handle contains the given handle in the most recently rendered frame.
 144    pub(crate) fn contains(&self, other: Self, cx: &WindowContext) -> bool {
 145        cx.window
 146            .rendered_frame
 147            .dispatch_tree
 148            .focus_contains(*self, other)
 149    }
 150}
 151
 152/// A handle which can be used to track and manipulate the focused element in a window.
 153pub struct FocusHandle {
 154    pub(crate) id: FocusId,
 155    handles: Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>,
 156}
 157
 158impl std::fmt::Debug for FocusHandle {
 159    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 160        f.write_fmt(format_args!("FocusHandle({:?})", self.id))
 161    }
 162}
 163
 164impl FocusHandle {
 165    pub(crate) fn new(handles: &Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>) -> Self {
 166        let id = handles.write().insert(AtomicUsize::new(1));
 167        Self {
 168            id,
 169            handles: handles.clone(),
 170        }
 171    }
 172
 173    pub(crate) fn for_id(
 174        id: FocusId,
 175        handles: &Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>,
 176    ) -> Option<Self> {
 177        let lock = handles.read();
 178        let ref_count = lock.get(id)?;
 179        if ref_count.load(SeqCst) == 0 {
 180            None
 181        } else {
 182            ref_count.fetch_add(1, SeqCst);
 183            Some(Self {
 184                id,
 185                handles: handles.clone(),
 186            })
 187        }
 188    }
 189
 190    /// Converts this focus handle into a weak variant, which does not prevent it from being released.
 191    pub fn downgrade(&self) -> WeakFocusHandle {
 192        WeakFocusHandle {
 193            id: self.id,
 194            handles: Arc::downgrade(&self.handles),
 195        }
 196    }
 197
 198    /// Moves the focus to the element associated with this handle.
 199    pub fn focus(&self, cx: &mut WindowContext) {
 200        cx.focus(self)
 201    }
 202
 203    /// Obtains whether the element associated with this handle is currently focused.
 204    pub fn is_focused(&self, cx: &WindowContext) -> bool {
 205        self.id.is_focused(cx)
 206    }
 207
 208    /// Obtains whether the element associated with this handle contains the focused
 209    /// element or is itself focused.
 210    pub fn contains_focused(&self, cx: &WindowContext) -> bool {
 211        self.id.contains_focused(cx)
 212    }
 213
 214    /// Obtains whether the element associated with this handle is contained within the
 215    /// focused element or is itself focused.
 216    pub fn within_focused(&self, cx: &WindowContext) -> bool {
 217        self.id.within_focused(cx)
 218    }
 219
 220    /// Obtains whether this handle contains the given handle in the most recently rendered frame.
 221    pub fn contains(&self, other: &Self, cx: &WindowContext) -> bool {
 222        self.id.contains(other.id, cx)
 223    }
 224
 225    /// Dispatch an action on the element that rendered this focus handle
 226    pub fn dispatch_action(&self, action: &dyn Action, cx: &mut WindowContext) {
 227        if let Some(node_id) = cx
 228            .window
 229            .rendered_frame
 230            .dispatch_tree
 231            .focusable_node_id(self.id)
 232        {
 233            cx.dispatch_action_on_node(node_id, action)
 234        }
 235    }
 236}
 237
 238impl Clone for FocusHandle {
 239    fn clone(&self) -> Self {
 240        Self::for_id(self.id, &self.handles).unwrap()
 241    }
 242}
 243
 244impl PartialEq for FocusHandle {
 245    fn eq(&self, other: &Self) -> bool {
 246        self.id == other.id
 247    }
 248}
 249
 250impl Eq for FocusHandle {}
 251
 252impl Drop for FocusHandle {
 253    fn drop(&mut self) {
 254        self.handles
 255            .read()
 256            .get(self.id)
 257            .unwrap()
 258            .fetch_sub(1, SeqCst);
 259    }
 260}
 261
 262/// A weak reference to a focus handle.
 263#[derive(Clone, Debug)]
 264pub struct WeakFocusHandle {
 265    pub(crate) id: FocusId,
 266    handles: Weak<RwLock<SlotMap<FocusId, AtomicUsize>>>,
 267}
 268
 269impl WeakFocusHandle {
 270    /// Attempts to upgrade the [WeakFocusHandle] to a [FocusHandle].
 271    pub fn upgrade(&self) -> Option<FocusHandle> {
 272        let handles = self.handles.upgrade()?;
 273        FocusHandle::for_id(self.id, &handles)
 274    }
 275}
 276
 277impl PartialEq for WeakFocusHandle {
 278    fn eq(&self, other: &WeakFocusHandle) -> bool {
 279        self.id == other.id
 280    }
 281}
 282
 283impl Eq for WeakFocusHandle {}
 284
 285impl PartialEq<FocusHandle> for WeakFocusHandle {
 286    fn eq(&self, other: &FocusHandle) -> bool {
 287        self.id == other.id
 288    }
 289}
 290
 291impl PartialEq<WeakFocusHandle> for FocusHandle {
 292    fn eq(&self, other: &WeakFocusHandle) -> bool {
 293        self.id == other.id
 294    }
 295}
 296
 297/// FocusableView allows users of your view to easily
 298/// focus it (using cx.focus_view(view))
 299pub trait FocusableView: 'static + Render {
 300    /// Returns the focus handle associated with this view.
 301    fn focus_handle(&self, cx: &AppContext) -> FocusHandle;
 302}
 303
 304/// ManagedView is a view (like a Modal, Popover, Menu, etc.)
 305/// where the lifecycle of the view is handled by another view.
 306pub trait ManagedView: FocusableView + EventEmitter<DismissEvent> {}
 307
 308impl<M: FocusableView + EventEmitter<DismissEvent>> ManagedView for M {}
 309
 310/// Emitted by implementers of [`ManagedView`] to indicate the view should be dismissed, such as when a view is presented as a modal.
 311pub struct DismissEvent;
 312
 313type FrameCallback = Box<dyn FnOnce(&mut WindowContext)>;
 314
 315pub(crate) type AnyMouseListener =
 316    Box<dyn FnMut(&dyn Any, DispatchPhase, &mut WindowContext) + 'static>;
 317
 318#[derive(Clone)]
 319pub(crate) struct CursorStyleRequest {
 320    pub(crate) hitbox_id: HitboxId,
 321    pub(crate) style: CursorStyle,
 322}
 323
 324/// An identifier for a [Hitbox].
 325#[derive(Copy, Clone, Debug, Default, Eq, PartialEq)]
 326pub struct HitboxId(usize);
 327
 328impl HitboxId {
 329    /// Checks if the hitbox with this id is currently hovered.
 330    pub fn is_hovered(&self, cx: &WindowContext) -> bool {
 331        cx.window.mouse_hit_test.0.contains(self)
 332    }
 333}
 334
 335/// A rectangular region that potentially blocks hitboxes inserted prior.
 336/// See [WindowContext::insert_hitbox] for more details.
 337#[derive(Clone, Debug, Deref)]
 338pub struct Hitbox {
 339    /// A unique identifier for the hitbox.
 340    pub id: HitboxId,
 341    /// The bounds of the hitbox.
 342    #[deref]
 343    pub bounds: Bounds<Pixels>,
 344    /// The content mask when the hitbox was inserted.
 345    pub content_mask: ContentMask<Pixels>,
 346    /// Whether the hitbox occludes other hitboxes inserted prior.
 347    pub opaque: bool,
 348}
 349
 350impl Hitbox {
 351    /// Checks if the hitbox is currently hovered.
 352    pub fn is_hovered(&self, cx: &WindowContext) -> bool {
 353        self.id.is_hovered(cx)
 354    }
 355}
 356
 357#[derive(Default, Eq, PartialEq)]
 358pub(crate) struct HitTest(SmallVec<[HitboxId; 8]>);
 359
 360/// An identifier for a tooltip.
 361#[derive(Copy, Clone, Debug, Default, Eq, PartialEq)]
 362pub struct TooltipId(usize);
 363
 364impl TooltipId {
 365    /// Checks if the tooltip is currently hovered.
 366    pub fn is_hovered(&self, cx: &WindowContext) -> bool {
 367        cx.window
 368            .tooltip_bounds
 369            .as_ref()
 370            .map_or(false, |tooltip_bounds| {
 371                tooltip_bounds.id == *self && tooltip_bounds.bounds.contains(&cx.mouse_position())
 372            })
 373    }
 374}
 375
 376pub(crate) struct TooltipBounds {
 377    id: TooltipId,
 378    bounds: Bounds<Pixels>,
 379}
 380
 381#[derive(Clone)]
 382pub(crate) struct TooltipRequest {
 383    id: TooltipId,
 384    tooltip: AnyTooltip,
 385}
 386
 387pub(crate) struct DeferredDraw {
 388    priority: usize,
 389    parent_node: DispatchNodeId,
 390    element_id_stack: SmallVec<[ElementId; 32]>,
 391    text_style_stack: Vec<TextStyleRefinement>,
 392    element: Option<AnyElement>,
 393    absolute_offset: Point<Pixels>,
 394    prepaint_range: Range<PrepaintStateIndex>,
 395    paint_range: Range<PaintIndex>,
 396}
 397
 398pub(crate) struct Frame {
 399    pub(crate) focus: Option<FocusId>,
 400    pub(crate) window_active: bool,
 401    pub(crate) element_states: FxHashMap<(GlobalElementId, TypeId), ElementStateBox>,
 402    accessed_element_states: Vec<(GlobalElementId, TypeId)>,
 403    pub(crate) mouse_listeners: Vec<Option<AnyMouseListener>>,
 404    pub(crate) dispatch_tree: DispatchTree,
 405    pub(crate) scene: Scene,
 406    pub(crate) hitboxes: Vec<Hitbox>,
 407    pub(crate) deferred_draws: Vec<DeferredDraw>,
 408    pub(crate) input_handlers: Vec<Option<PlatformInputHandler>>,
 409    pub(crate) tooltip_requests: Vec<Option<TooltipRequest>>,
 410    pub(crate) cursor_styles: Vec<CursorStyleRequest>,
 411    #[cfg(any(test, feature = "test-support"))]
 412    pub(crate) debug_bounds: FxHashMap<String, Bounds<Pixels>>,
 413}
 414
 415#[derive(Clone, Default)]
 416pub(crate) struct PrepaintStateIndex {
 417    hitboxes_index: usize,
 418    tooltips_index: usize,
 419    deferred_draws_index: usize,
 420    dispatch_tree_index: usize,
 421    accessed_element_states_index: usize,
 422    line_layout_index: LineLayoutIndex,
 423}
 424
 425#[derive(Clone, Default)]
 426pub(crate) struct PaintIndex {
 427    scene_index: usize,
 428    mouse_listeners_index: usize,
 429    input_handlers_index: usize,
 430    cursor_styles_index: usize,
 431    accessed_element_states_index: usize,
 432    line_layout_index: LineLayoutIndex,
 433}
 434
 435impl Frame {
 436    pub(crate) fn new(dispatch_tree: DispatchTree) -> Self {
 437        Frame {
 438            focus: None,
 439            window_active: false,
 440            element_states: FxHashMap::default(),
 441            accessed_element_states: Vec::new(),
 442            mouse_listeners: Vec::new(),
 443            dispatch_tree,
 444            scene: Scene::default(),
 445            hitboxes: Vec::new(),
 446            deferred_draws: Vec::new(),
 447            input_handlers: Vec::new(),
 448            tooltip_requests: Vec::new(),
 449            cursor_styles: Vec::new(),
 450
 451            #[cfg(any(test, feature = "test-support"))]
 452            debug_bounds: FxHashMap::default(),
 453        }
 454    }
 455
 456    pub(crate) fn clear(&mut self) {
 457        self.element_states.clear();
 458        self.accessed_element_states.clear();
 459        self.mouse_listeners.clear();
 460        self.dispatch_tree.clear();
 461        self.scene.clear();
 462        self.input_handlers.clear();
 463        self.tooltip_requests.clear();
 464        self.cursor_styles.clear();
 465        self.hitboxes.clear();
 466        self.deferred_draws.clear();
 467        self.focus = None;
 468    }
 469
 470    pub(crate) fn hit_test(&self, position: Point<Pixels>) -> HitTest {
 471        let mut hit_test = HitTest::default();
 472        for hitbox in self.hitboxes.iter().rev() {
 473            let bounds = hitbox.bounds.intersect(&hitbox.content_mask.bounds);
 474            if bounds.contains(&position) {
 475                hit_test.0.push(hitbox.id);
 476                if hitbox.opaque {
 477                    break;
 478                }
 479            }
 480        }
 481        hit_test
 482    }
 483
 484    pub(crate) fn focus_path(&self) -> SmallVec<[FocusId; 8]> {
 485        self.focus
 486            .map(|focus_id| self.dispatch_tree.focus_path(focus_id))
 487            .unwrap_or_default()
 488    }
 489
 490    pub(crate) fn finish(&mut self, prev_frame: &mut Self) {
 491        for element_state_key in &self.accessed_element_states {
 492            if let Some((element_state_key, element_state)) =
 493                prev_frame.element_states.remove_entry(element_state_key)
 494            {
 495                self.element_states.insert(element_state_key, element_state);
 496            }
 497        }
 498
 499        self.scene.finish();
 500    }
 501}
 502
 503// Holds the state for a specific window.
 504#[doc(hidden)]
 505pub struct Window {
 506    pub(crate) handle: AnyWindowHandle,
 507    pub(crate) removed: bool,
 508    pub(crate) platform_window: Box<dyn PlatformWindow>,
 509    display_id: Option<DisplayId>,
 510    sprite_atlas: Arc<dyn PlatformAtlas>,
 511    text_system: Arc<WindowTextSystem>,
 512    rem_size: Pixels,
 513    /// The stack of override values for the window's rem size.
 514    ///
 515    /// This is used by `with_rem_size` to allow rendering an element tree with
 516    /// a given rem size.
 517    rem_size_override_stack: SmallVec<[Pixels; 8]>,
 518    pub(crate) viewport_size: Size<Pixels>,
 519    layout_engine: Option<TaffyLayoutEngine>,
 520    pub(crate) root_view: Option<AnyView>,
 521    pub(crate) element_id_stack: SmallVec<[ElementId; 32]>,
 522    pub(crate) text_style_stack: Vec<TextStyleRefinement>,
 523    pub(crate) element_offset_stack: Vec<Point<Pixels>>,
 524    pub(crate) content_mask_stack: Vec<ContentMask<Pixels>>,
 525    pub(crate) requested_autoscroll: Option<Bounds<Pixels>>,
 526    pub(crate) rendered_frame: Frame,
 527    pub(crate) next_frame: Frame,
 528    pub(crate) next_hitbox_id: HitboxId,
 529    pub(crate) next_tooltip_id: TooltipId,
 530    pub(crate) tooltip_bounds: Option<TooltipBounds>,
 531    next_frame_callbacks: Rc<RefCell<Vec<FrameCallback>>>,
 532    pub(crate) dirty_views: FxHashSet<EntityId>,
 533    pub(crate) focus_handles: Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>,
 534    focus_listeners: SubscriberSet<(), AnyWindowFocusListener>,
 535    focus_lost_listeners: SubscriberSet<(), AnyObserver>,
 536    default_prevented: bool,
 537    mouse_position: Point<Pixels>,
 538    mouse_hit_test: HitTest,
 539    modifiers: Modifiers,
 540    scale_factor: f32,
 541    bounds_observers: SubscriberSet<(), AnyObserver>,
 542    appearance: WindowAppearance,
 543    appearance_observers: SubscriberSet<(), AnyObserver>,
 544    active: Rc<Cell<bool>>,
 545    hovered: Rc<Cell<bool>>,
 546    pub(crate) dirty: Rc<Cell<bool>>,
 547    pub(crate) needs_present: Rc<Cell<bool>>,
 548    pub(crate) last_input_timestamp: Rc<Cell<Instant>>,
 549    pub(crate) refreshing: bool,
 550    pub(crate) draw_phase: DrawPhase,
 551    activation_observers: SubscriberSet<(), AnyObserver>,
 552    pub(crate) focus: Option<FocusId>,
 553    focus_enabled: bool,
 554    pending_input: Option<PendingInput>,
 555    pending_modifier: ModifierState,
 556    pending_input_observers: SubscriberSet<(), AnyObserver>,
 557    prompt: Option<RenderablePromptHandle>,
 558}
 559
 560#[derive(Clone, Debug, Default)]
 561struct ModifierState {
 562    modifiers: Modifiers,
 563    saw_keystroke: bool,
 564}
 565
 566#[derive(Clone, Copy, Debug, Eq, PartialEq)]
 567pub(crate) enum DrawPhase {
 568    None,
 569    Prepaint,
 570    Paint,
 571    Focus,
 572}
 573
 574#[derive(Default, Debug)]
 575struct PendingInput {
 576    keystrokes: SmallVec<[Keystroke; 1]>,
 577    focus: Option<FocusId>,
 578    timer: Option<Task<()>>,
 579}
 580
 581pub(crate) struct ElementStateBox {
 582    pub(crate) inner: Box<dyn Any>,
 583    #[cfg(debug_assertions)]
 584    pub(crate) type_name: &'static str,
 585}
 586
 587fn default_bounds(display_id: Option<DisplayId>, cx: &mut AppContext) -> Bounds<Pixels> {
 588    const DEFAULT_WINDOW_OFFSET: Point<Pixels> = point(px(0.), px(35.));
 589
 590    cx.active_window()
 591        .and_then(|w| w.update(cx, |_, cx| cx.bounds()).ok())
 592        .map(|mut bounds| {
 593            bounds.origin += DEFAULT_WINDOW_OFFSET;
 594            bounds
 595        })
 596        .unwrap_or_else(|| {
 597            let display = display_id
 598                .map(|id| cx.find_display(id))
 599                .unwrap_or_else(|| cx.primary_display());
 600
 601            display
 602                .map(|display| display.default_bounds())
 603                .unwrap_or_else(|| Bounds::new(point(px(0.), px(0.)), DEFAULT_WINDOW_SIZE))
 604        })
 605}
 606
 607impl Window {
 608    pub(crate) fn new(
 609        handle: AnyWindowHandle,
 610        options: WindowOptions,
 611        cx: &mut AppContext,
 612    ) -> Result<Self> {
 613        let WindowOptions {
 614            window_bounds,
 615            titlebar,
 616            focus,
 617            show,
 618            kind,
 619            is_movable,
 620            display_id,
 621            window_background,
 622            app_id,
 623            window_min_size,
 624            window_decorations,
 625        } = options;
 626
 627        let bounds = window_bounds
 628            .map(|bounds| bounds.get_bounds())
 629            .unwrap_or_else(|| default_bounds(display_id, cx));
 630        let mut platform_window = cx.platform.open_window(
 631            handle,
 632            WindowParams {
 633                bounds,
 634                titlebar,
 635                kind,
 636                is_movable,
 637                focus,
 638                show,
 639                display_id,
 640                window_min_size,
 641            },
 642        )?;
 643        let display_id = platform_window.display().map(|display| display.id());
 644        let sprite_atlas = platform_window.sprite_atlas();
 645        let mouse_position = platform_window.mouse_position();
 646        let modifiers = platform_window.modifiers();
 647        let content_size = platform_window.content_size();
 648        let scale_factor = platform_window.scale_factor();
 649        let appearance = platform_window.appearance();
 650        let text_system = Arc::new(WindowTextSystem::new(cx.text_system().clone()));
 651        let dirty = Rc::new(Cell::new(true));
 652        let active = Rc::new(Cell::new(platform_window.is_active()));
 653        let hovered = Rc::new(Cell::new(platform_window.is_hovered()));
 654        let needs_present = Rc::new(Cell::new(false));
 655        let next_frame_callbacks: Rc<RefCell<Vec<FrameCallback>>> = Default::default();
 656        let last_input_timestamp = Rc::new(Cell::new(Instant::now()));
 657
 658        platform_window
 659            .request_decorations(window_decorations.unwrap_or(WindowDecorations::Server));
 660        platform_window.set_background_appearance(window_background);
 661
 662        if let Some(ref window_open_state) = window_bounds {
 663            match window_open_state {
 664                WindowBounds::Fullscreen(_) => platform_window.toggle_fullscreen(),
 665                WindowBounds::Maximized(_) => platform_window.zoom(),
 666                WindowBounds::Windowed(_) => {}
 667            }
 668        }
 669
 670        platform_window.on_close(Box::new({
 671            let mut cx = cx.to_async();
 672            move || {
 673                let _ = handle.update(&mut cx, |_, cx| cx.remove_window());
 674            }
 675        }));
 676        platform_window.on_request_frame(Box::new({
 677            let mut cx = cx.to_async();
 678            let dirty = dirty.clone();
 679            let active = active.clone();
 680            let needs_present = needs_present.clone();
 681            let next_frame_callbacks = next_frame_callbacks.clone();
 682            let last_input_timestamp = last_input_timestamp.clone();
 683            move || {
 684                let next_frame_callbacks = next_frame_callbacks.take();
 685                if !next_frame_callbacks.is_empty() {
 686                    handle
 687                        .update(&mut cx, |_, cx| {
 688                            for callback in next_frame_callbacks {
 689                                callback(cx);
 690                            }
 691                        })
 692                        .log_err();
 693                }
 694
 695                // Keep presenting the current scene for 1 extra second since the
 696                // last input to prevent the display from underclocking the refresh rate.
 697                let needs_present = needs_present.get()
 698                    || (active.get()
 699                        && last_input_timestamp.get().elapsed() < Duration::from_secs(1));
 700
 701                if dirty.get() {
 702                    measure("frame duration", || {
 703                        handle
 704                            .update(&mut cx, |_, cx| {
 705                                cx.draw();
 706                                cx.present();
 707                            })
 708                            .log_err();
 709                    })
 710                } else if needs_present {
 711                    handle.update(&mut cx, |_, cx| cx.present()).log_err();
 712                }
 713
 714                handle
 715                    .update(&mut cx, |_, cx| {
 716                        cx.complete_frame();
 717                    })
 718                    .log_err();
 719            }
 720        }));
 721        platform_window.on_resize(Box::new({
 722            let mut cx = cx.to_async();
 723            move |_, _| {
 724                handle
 725                    .update(&mut cx, |_, cx| cx.bounds_changed())
 726                    .log_err();
 727            }
 728        }));
 729        platform_window.on_moved(Box::new({
 730            let mut cx = cx.to_async();
 731            move || {
 732                handle
 733                    .update(&mut cx, |_, cx| cx.bounds_changed())
 734                    .log_err();
 735            }
 736        }));
 737        platform_window.on_appearance_changed(Box::new({
 738            let mut cx = cx.to_async();
 739            move || {
 740                handle
 741                    .update(&mut cx, |_, cx| cx.appearance_changed())
 742                    .log_err();
 743            }
 744        }));
 745        platform_window.on_active_status_change(Box::new({
 746            let mut cx = cx.to_async();
 747            move |active| {
 748                handle
 749                    .update(&mut cx, |_, cx| {
 750                        cx.window.active.set(active);
 751                        cx.window
 752                            .activation_observers
 753                            .clone()
 754                            .retain(&(), |callback| callback(cx));
 755                        cx.refresh();
 756                    })
 757                    .log_err();
 758            }
 759        }));
 760        platform_window.on_hover_status_change(Box::new({
 761            let mut cx = cx.to_async();
 762            move |active| {
 763                handle
 764                    .update(&mut cx, |_, cx| {
 765                        cx.window.hovered.set(active);
 766                        cx.refresh();
 767                    })
 768                    .log_err();
 769            }
 770        }));
 771        platform_window.on_input({
 772            let mut cx = cx.to_async();
 773            Box::new(move |event| {
 774                handle
 775                    .update(&mut cx, |_, cx| cx.dispatch_event(event))
 776                    .log_err()
 777                    .unwrap_or(DispatchEventResult::default())
 778            })
 779        });
 780
 781        if let Some(app_id) = app_id {
 782            platform_window.set_app_id(&app_id);
 783        }
 784
 785        Ok(Window {
 786            handle,
 787            removed: false,
 788            platform_window,
 789            display_id,
 790            sprite_atlas,
 791            text_system,
 792            rem_size: px(16.),
 793            rem_size_override_stack: SmallVec::new(),
 794            viewport_size: content_size,
 795            layout_engine: Some(TaffyLayoutEngine::new()),
 796            root_view: None,
 797            element_id_stack: SmallVec::default(),
 798            text_style_stack: Vec::new(),
 799            element_offset_stack: Vec::new(),
 800            content_mask_stack: Vec::new(),
 801            requested_autoscroll: None,
 802            rendered_frame: Frame::new(DispatchTree::new(cx.keymap.clone(), cx.actions.clone())),
 803            next_frame: Frame::new(DispatchTree::new(cx.keymap.clone(), cx.actions.clone())),
 804            next_frame_callbacks,
 805            next_hitbox_id: HitboxId::default(),
 806            next_tooltip_id: TooltipId::default(),
 807            tooltip_bounds: None,
 808            dirty_views: FxHashSet::default(),
 809            focus_handles: Arc::new(RwLock::new(SlotMap::with_key())),
 810            focus_listeners: SubscriberSet::new(),
 811            focus_lost_listeners: SubscriberSet::new(),
 812            default_prevented: true,
 813            mouse_position,
 814            mouse_hit_test: HitTest::default(),
 815            modifiers,
 816            scale_factor,
 817            bounds_observers: SubscriberSet::new(),
 818            appearance,
 819            appearance_observers: SubscriberSet::new(),
 820            active,
 821            hovered,
 822            dirty,
 823            needs_present,
 824            last_input_timestamp,
 825            refreshing: false,
 826            draw_phase: DrawPhase::None,
 827            activation_observers: SubscriberSet::new(),
 828            focus: None,
 829            focus_enabled: true,
 830            pending_input: None,
 831            pending_modifier: ModifierState::default(),
 832            pending_input_observers: SubscriberSet::new(),
 833            prompt: None,
 834        })
 835    }
 836    fn new_focus_listener(
 837        &mut self,
 838        value: AnyWindowFocusListener,
 839    ) -> (Subscription, impl FnOnce()) {
 840        self.focus_listeners.insert((), value)
 841    }
 842}
 843
 844#[derive(Clone, Debug, Default, PartialEq, Eq)]
 845pub(crate) struct DispatchEventResult {
 846    pub propagate: bool,
 847    pub default_prevented: bool,
 848}
 849
 850/// Indicates which region of the window is visible. Content falling outside of this mask will not be
 851/// rendered. Currently, only rectangular content masks are supported, but we give the mask its own type
 852/// to leave room to support more complex shapes in the future.
 853#[derive(Clone, Debug, Default, PartialEq, Eq)]
 854#[repr(C)]
 855pub struct ContentMask<P: Clone + Default + Debug> {
 856    /// The bounds
 857    pub bounds: Bounds<P>,
 858}
 859
 860impl ContentMask<Pixels> {
 861    /// Scale the content mask's pixel units by the given scaling factor.
 862    pub fn scale(&self, factor: f32) -> ContentMask<ScaledPixels> {
 863        ContentMask {
 864            bounds: self.bounds.scale(factor),
 865        }
 866    }
 867
 868    /// Intersect the content mask with the given content mask.
 869    pub fn intersect(&self, other: &Self) -> Self {
 870        let bounds = self.bounds.intersect(&other.bounds);
 871        ContentMask { bounds }
 872    }
 873}
 874
 875/// Provides access to application state in the context of a single window. Derefs
 876/// to an [`AppContext`], so you can also pass a [`WindowContext`] to any method that takes
 877/// an [`AppContext`] and call any [`AppContext`] methods.
 878pub struct WindowContext<'a> {
 879    pub(crate) app: &'a mut AppContext,
 880    pub(crate) window: &'a mut Window,
 881}
 882
 883impl<'a> WindowContext<'a> {
 884    pub(crate) fn new(app: &'a mut AppContext, window: &'a mut Window) -> Self {
 885        Self { app, window }
 886    }
 887
 888    /// Obtain a handle to the window that belongs to this context.
 889    pub fn window_handle(&self) -> AnyWindowHandle {
 890        self.window.handle
 891    }
 892
 893    /// Mark the window as dirty, scheduling it to be redrawn on the next frame.
 894    pub fn refresh(&mut self) {
 895        if self.window.draw_phase == DrawPhase::None {
 896            self.window.refreshing = true;
 897            self.window.dirty.set(true);
 898        }
 899    }
 900
 901    /// Indicate that this view has changed, which will invoke any observers and also mark the window as dirty.
 902    /// If this view or any of its ancestors are *cached*, notifying it will cause it or its ancestors to be redrawn.
 903    pub fn notify(&mut self, view_id: EntityId) {
 904        for view_id in self
 905            .window
 906            .rendered_frame
 907            .dispatch_tree
 908            .view_path(view_id)
 909            .into_iter()
 910            .rev()
 911        {
 912            if !self.window.dirty_views.insert(view_id) {
 913                break;
 914            }
 915        }
 916
 917        if self.window.draw_phase == DrawPhase::None {
 918            self.window.dirty.set(true);
 919            self.app.push_effect(Effect::Notify { emitter: view_id });
 920        }
 921    }
 922
 923    /// Close this window.
 924    pub fn remove_window(&mut self) {
 925        self.window.removed = true;
 926    }
 927
 928    /// Obtain a new [`FocusHandle`], which allows you to track and manipulate the keyboard focus
 929    /// for elements rendered within this window.
 930    pub fn focus_handle(&mut self) -> FocusHandle {
 931        FocusHandle::new(&self.window.focus_handles)
 932    }
 933
 934    /// Obtain the currently focused [`FocusHandle`]. If no elements are focused, returns `None`.
 935    pub fn focused(&self) -> Option<FocusHandle> {
 936        self.window
 937            .focus
 938            .and_then(|id| FocusHandle::for_id(id, &self.window.focus_handles))
 939    }
 940
 941    /// Move focus to the element associated with the given [`FocusHandle`].
 942    pub fn focus(&mut self, handle: &FocusHandle) {
 943        if !self.window.focus_enabled || self.window.focus == Some(handle.id) {
 944            return;
 945        }
 946
 947        self.window.focus = Some(handle.id);
 948        self.clear_pending_keystrokes();
 949        self.refresh();
 950    }
 951
 952    /// Remove focus from all elements within this context's window.
 953    pub fn blur(&mut self) {
 954        if !self.window.focus_enabled {
 955            return;
 956        }
 957
 958        self.window.focus = None;
 959        self.refresh();
 960    }
 961
 962    /// Blur the window and don't allow anything in it to be focused again.
 963    pub fn disable_focus(&mut self) {
 964        self.blur();
 965        self.window.focus_enabled = false;
 966    }
 967
 968    /// Accessor for the text system.
 969    pub fn text_system(&self) -> &Arc<WindowTextSystem> {
 970        &self.window.text_system
 971    }
 972
 973    /// The current text style. Which is composed of all the style refinements provided to `with_text_style`.
 974    pub fn text_style(&self) -> TextStyle {
 975        let mut style = TextStyle::default();
 976        for refinement in &self.window.text_style_stack {
 977            style.refine(refinement);
 978        }
 979        style
 980    }
 981
 982    /// Check if the platform window is maximized
 983    /// On some platforms (namely Windows) this is different than the bounds being the size of the display
 984    pub fn is_maximized(&self) -> bool {
 985        self.window.platform_window.is_maximized()
 986    }
 987
 988    /// request a certain window decoration (Wayland)
 989    pub fn request_decorations(&self, decorations: WindowDecorations) {
 990        self.window.platform_window.request_decorations(decorations);
 991    }
 992
 993    /// Start a window resize operation (Wayland)
 994    pub fn start_window_resize(&self, edge: ResizeEdge) {
 995        self.window.platform_window.start_window_resize(edge);
 996    }
 997
 998    /// Return the `WindowBounds` to indicate that how a window should be opened
 999    /// after it has been closed
1000    pub fn window_bounds(&self) -> WindowBounds {
1001        self.window.platform_window.window_bounds()
1002    }
1003
1004    /// Dispatch the given action on the currently focused element.
1005    pub fn dispatch_action(&mut self, action: Box<dyn Action>) {
1006        let focus_handle = self.focused();
1007
1008        let window = self.window.handle;
1009        self.app.defer(move |cx| {
1010            window
1011                .update(cx, |_, cx| {
1012                    let node_id = focus_handle
1013                        .and_then(|handle| {
1014                            cx.window
1015                                .rendered_frame
1016                                .dispatch_tree
1017                                .focusable_node_id(handle.id)
1018                        })
1019                        .unwrap_or_else(|| cx.window.rendered_frame.dispatch_tree.root_node_id());
1020
1021                    cx.dispatch_action_on_node(node_id, action.as_ref());
1022                })
1023                .log_err();
1024        })
1025    }
1026
1027    pub(crate) fn dispatch_keystroke_observers(
1028        &mut self,
1029        event: &dyn Any,
1030        action: Option<Box<dyn Action>>,
1031    ) {
1032        let Some(key_down_event) = event.downcast_ref::<KeyDownEvent>() else {
1033            return;
1034        };
1035
1036        self.keystroke_observers
1037            .clone()
1038            .retain(&(), move |callback| {
1039                (callback)(
1040                    &KeystrokeEvent {
1041                        keystroke: key_down_event.keystroke.clone(),
1042                        action: action.as_ref().map(|action| action.boxed_clone()),
1043                    },
1044                    self,
1045                );
1046                true
1047            });
1048    }
1049
1050    /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
1051    /// that are currently on the stack to be returned to the app.
1052    pub fn defer(&mut self, f: impl FnOnce(&mut WindowContext) + 'static) {
1053        let handle = self.window.handle;
1054        self.app.defer(move |cx| {
1055            handle.update(cx, |_, cx| f(cx)).ok();
1056        });
1057    }
1058
1059    /// Subscribe to events emitted by a model or view.
1060    /// The entity to which you're subscribing must implement the [`EventEmitter`] trait.
1061    /// 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.
1062    pub fn observe<E, T>(
1063        &mut self,
1064        entity: &E,
1065        mut on_notify: impl FnMut(E, &mut WindowContext<'_>) + 'static,
1066    ) -> Subscription
1067    where
1068        E: Entity<T>,
1069    {
1070        let entity_id = entity.entity_id();
1071        let entity = entity.downgrade();
1072        let window_handle = self.window.handle;
1073        self.app.new_observer(
1074            entity_id,
1075            Box::new(move |cx| {
1076                window_handle
1077                    .update(cx, |_, cx| {
1078                        if let Some(handle) = E::upgrade_from(&entity) {
1079                            on_notify(handle, cx);
1080                            true
1081                        } else {
1082                            false
1083                        }
1084                    })
1085                    .unwrap_or(false)
1086            }),
1087        )
1088    }
1089
1090    /// Subscribe to events emitted by a model or view.
1091    /// The entity to which you're subscribing must implement the [`EventEmitter`] trait.
1092    /// 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.
1093    pub fn subscribe<Emitter, E, Evt>(
1094        &mut self,
1095        entity: &E,
1096        mut on_event: impl FnMut(E, &Evt, &mut WindowContext<'_>) + 'static,
1097    ) -> Subscription
1098    where
1099        Emitter: EventEmitter<Evt>,
1100        E: Entity<Emitter>,
1101        Evt: 'static,
1102    {
1103        let entity_id = entity.entity_id();
1104        let entity = entity.downgrade();
1105        let window_handle = self.window.handle;
1106        self.app.new_subscription(
1107            entity_id,
1108            (
1109                TypeId::of::<Evt>(),
1110                Box::new(move |event, cx| {
1111                    window_handle
1112                        .update(cx, |_, cx| {
1113                            if let Some(handle) = E::upgrade_from(&entity) {
1114                                let event = event.downcast_ref().expect("invalid event type");
1115                                on_event(handle, event, cx);
1116                                true
1117                            } else {
1118                                false
1119                            }
1120                        })
1121                        .unwrap_or(false)
1122                }),
1123            ),
1124        )
1125    }
1126
1127    /// Register a callback to be invoked when the given Model or View is released.
1128    pub fn observe_release<E, T>(
1129        &mut self,
1130        entity: &E,
1131        mut on_release: impl FnOnce(&mut T, &mut WindowContext) + 'static,
1132    ) -> Subscription
1133    where
1134        E: Entity<T>,
1135        T: 'static,
1136    {
1137        let entity_id = entity.entity_id();
1138        let window_handle = self.window.handle;
1139        let (subscription, activate) = self.app.release_listeners.insert(
1140            entity_id,
1141            Box::new(move |entity, cx| {
1142                let entity = entity.downcast_mut().expect("invalid entity type");
1143                let _ = window_handle.update(cx, |_, cx| on_release(entity, cx));
1144            }),
1145        );
1146        activate();
1147        subscription
1148    }
1149
1150    /// Creates an [`AsyncWindowContext`], which has a static lifetime and can be held across
1151    /// await points in async code.
1152    pub fn to_async(&self) -> AsyncWindowContext {
1153        AsyncWindowContext::new(self.app.to_async(), self.window.handle)
1154    }
1155
1156    /// Schedule the given closure to be run directly after the current frame is rendered.
1157    pub fn on_next_frame(&mut self, callback: impl FnOnce(&mut WindowContext) + 'static) {
1158        RefCell::borrow_mut(&self.window.next_frame_callbacks).push(Box::new(callback));
1159    }
1160
1161    /// Spawn the future returned by the given closure on the application thread pool.
1162    /// The closure is provided a handle to the current window and an `AsyncWindowContext` for
1163    /// use within your future.
1164    pub fn spawn<Fut, R>(&mut self, f: impl FnOnce(AsyncWindowContext) -> Fut) -> Task<R>
1165    where
1166        R: 'static,
1167        Fut: Future<Output = R> + 'static,
1168    {
1169        self.app
1170            .spawn(|app| f(AsyncWindowContext::new(app, self.window.handle)))
1171    }
1172
1173    fn bounds_changed(&mut self) {
1174        self.window.scale_factor = self.window.platform_window.scale_factor();
1175        self.window.viewport_size = self.window.platform_window.content_size();
1176        self.window.display_id = self
1177            .window
1178            .platform_window
1179            .display()
1180            .map(|display| display.id());
1181
1182        self.refresh();
1183
1184        self.window
1185            .bounds_observers
1186            .clone()
1187            .retain(&(), |callback| callback(self));
1188    }
1189
1190    /// Returns the bounds of the current window in the global coordinate space, which could span across multiple displays.
1191    pub fn bounds(&self) -> Bounds<Pixels> {
1192        self.window.platform_window.bounds()
1193    }
1194
1195    /// Returns whether or not the window is currently fullscreen
1196    pub fn is_fullscreen(&self) -> bool {
1197        self.window.platform_window.is_fullscreen()
1198    }
1199
1200    pub(crate) fn appearance_changed(&mut self) {
1201        self.window.appearance = self.window.platform_window.appearance();
1202
1203        self.window
1204            .appearance_observers
1205            .clone()
1206            .retain(&(), |callback| callback(self));
1207    }
1208
1209    /// Returns the appearance of the current window.
1210    pub fn appearance(&self) -> WindowAppearance {
1211        self.window.appearance
1212    }
1213
1214    /// Returns the size of the drawable area within the window.
1215    pub fn viewport_size(&self) -> Size<Pixels> {
1216        self.window.viewport_size
1217    }
1218
1219    /// Returns whether this window is focused by the operating system (receiving key events).
1220    pub fn is_window_active(&self) -> bool {
1221        self.window.active.get()
1222    }
1223
1224    /// Returns whether this window is considered to be the window
1225    /// that currently owns the mouse cursor.
1226    /// On mac, this is equivalent to `is_window_active`.
1227    pub fn is_window_hovered(&self) -> bool {
1228        if cfg!(target_os = "linux") {
1229            self.window.hovered.get()
1230        } else {
1231            self.is_window_active()
1232        }
1233    }
1234
1235    /// Toggle zoom on the window.
1236    pub fn zoom_window(&self) {
1237        self.window.platform_window.zoom();
1238    }
1239
1240    /// Opens the native title bar context menu, useful when implementing client side decorations (Wayland and X11)
1241    pub fn show_window_menu(&self, position: Point<Pixels>) {
1242        self.window.platform_window.show_window_menu(position)
1243    }
1244
1245    /// Tells the compositor to take control of window movement (Wayland and X11)
1246    ///
1247    /// Events may not be received during a move operation.
1248    pub fn start_window_move(&self) {
1249        self.window.platform_window.start_window_move()
1250    }
1251
1252    /// When using client side decorations, set this to the width of the invisible decorations (Wayland and X11)
1253    pub fn set_client_inset(&self, inset: Pixels) {
1254        self.window.platform_window.set_client_inset(inset);
1255    }
1256
1257    /// Returns whether the title bar window controls need to be rendered by the application (Wayland and X11)
1258    pub fn window_decorations(&self) -> Decorations {
1259        self.window.platform_window.window_decorations()
1260    }
1261
1262    /// Returns which window controls are currently visible (Wayland)
1263    pub fn window_controls(&self) -> WindowControls {
1264        self.window.platform_window.window_controls()
1265    }
1266
1267    /// Updates the window's title at the platform level.
1268    pub fn set_window_title(&mut self, title: &str) {
1269        self.window.platform_window.set_title(title);
1270    }
1271
1272    /// Sets the application identifier.
1273    pub fn set_app_id(&mut self, app_id: &str) {
1274        self.window.platform_window.set_app_id(app_id);
1275    }
1276
1277    /// Sets the window background appearance.
1278    pub fn set_background_appearance(&self, background_appearance: WindowBackgroundAppearance) {
1279        self.window
1280            .platform_window
1281            .set_background_appearance(background_appearance);
1282    }
1283
1284    /// Mark the window as dirty at the platform level.
1285    pub fn set_window_edited(&mut self, edited: bool) {
1286        self.window.platform_window.set_edited(edited);
1287    }
1288
1289    /// Determine the display on which the window is visible.
1290    pub fn display(&self) -> Option<Rc<dyn PlatformDisplay>> {
1291        self.platform
1292            .displays()
1293            .into_iter()
1294            .find(|display| Some(display.id()) == self.window.display_id)
1295    }
1296
1297    /// Show the platform character palette.
1298    pub fn show_character_palette(&self) {
1299        self.window.platform_window.show_character_palette();
1300    }
1301
1302    /// The scale factor of the display associated with the window. For example, it could
1303    /// return 2.0 for a "retina" display, indicating that each logical pixel should actually
1304    /// be rendered as two pixels on screen.
1305    pub fn scale_factor(&self) -> f32 {
1306        self.window.scale_factor
1307    }
1308
1309    /// The size of an em for the base font of the application. Adjusting this value allows the
1310    /// UI to scale, just like zooming a web page.
1311    pub fn rem_size(&self) -> Pixels {
1312        self.window
1313            .rem_size_override_stack
1314            .last()
1315            .copied()
1316            .unwrap_or(self.window.rem_size)
1317    }
1318
1319    /// Sets the size of an em for the base font of the application. Adjusting this value allows the
1320    /// UI to scale, just like zooming a web page.
1321    pub fn set_rem_size(&mut self, rem_size: impl Into<Pixels>) {
1322        self.window.rem_size = rem_size.into();
1323    }
1324
1325    /// Executes the provided function with the specified rem size.
1326    ///
1327    /// This method must only be called as part of element drawing.
1328    pub fn with_rem_size<F, R>(&mut self, rem_size: Option<impl Into<Pixels>>, f: F) -> R
1329    where
1330        F: FnOnce(&mut Self) -> R,
1331    {
1332        debug_assert!(
1333            matches!(
1334                self.window.draw_phase,
1335                DrawPhase::Prepaint | DrawPhase::Paint
1336            ),
1337            "this method can only be called during request_layout, prepaint, or paint"
1338        );
1339
1340        if let Some(rem_size) = rem_size {
1341            self.window.rem_size_override_stack.push(rem_size.into());
1342            let result = f(self);
1343            self.window.rem_size_override_stack.pop();
1344            result
1345        } else {
1346            f(self)
1347        }
1348    }
1349
1350    /// The line height associated with the current text style.
1351    pub fn line_height(&self) -> Pixels {
1352        let rem_size = self.rem_size();
1353        let text_style = self.text_style();
1354        text_style
1355            .line_height
1356            .to_pixels(text_style.font_size, rem_size)
1357    }
1358
1359    /// Call to prevent the default action of an event. Currently only used to prevent
1360    /// parent elements from becoming focused on mouse down.
1361    pub fn prevent_default(&mut self) {
1362        self.window.default_prevented = true;
1363    }
1364
1365    /// Obtain whether default has been prevented for the event currently being dispatched.
1366    pub fn default_prevented(&self) -> bool {
1367        self.window.default_prevented
1368    }
1369
1370    /// Determine whether the given action is available along the dispatch path to the currently focused element.
1371    pub fn is_action_available(&self, action: &dyn Action) -> bool {
1372        let target = self
1373            .focused()
1374            .and_then(|focused_handle| {
1375                self.window
1376                    .rendered_frame
1377                    .dispatch_tree
1378                    .focusable_node_id(focused_handle.id)
1379            })
1380            .unwrap_or_else(|| self.window.rendered_frame.dispatch_tree.root_node_id());
1381        self.window
1382            .rendered_frame
1383            .dispatch_tree
1384            .is_action_available(action, target)
1385    }
1386
1387    /// The position of the mouse relative to the window.
1388    pub fn mouse_position(&self) -> Point<Pixels> {
1389        self.window.mouse_position
1390    }
1391
1392    /// The current state of the keyboard's modifiers
1393    pub fn modifiers(&self) -> Modifiers {
1394        self.window.modifiers
1395    }
1396
1397    fn complete_frame(&self) {
1398        self.window.platform_window.completed_frame();
1399    }
1400
1401    /// Produces a new frame and assigns it to `rendered_frame`. To actually show
1402    /// the contents of the new [Scene], use [present].
1403    #[profiling::function]
1404    pub fn draw(&mut self) {
1405        self.window.dirty.set(false);
1406        self.window.requested_autoscroll = None;
1407
1408        // Restore the previously-used input handler.
1409        if let Some(input_handler) = self.window.platform_window.take_input_handler() {
1410            self.window
1411                .rendered_frame
1412                .input_handlers
1413                .push(Some(input_handler));
1414        }
1415
1416        self.draw_roots();
1417        self.window.dirty_views.clear();
1418        self.window.next_frame.window_active = self.window.active.get();
1419
1420        // Register requested input handler with the platform window.
1421        if let Some(input_handler) = self.window.next_frame.input_handlers.pop() {
1422            self.window
1423                .platform_window
1424                .set_input_handler(input_handler.unwrap());
1425        }
1426
1427        self.window.layout_engine.as_mut().unwrap().clear();
1428        self.text_system().finish_frame();
1429        self.window
1430            .next_frame
1431            .finish(&mut self.window.rendered_frame);
1432        ELEMENT_ARENA.with_borrow_mut(|element_arena| {
1433            let percentage = (element_arena.len() as f32 / element_arena.capacity() as f32) * 100.;
1434            if percentage >= 80. {
1435                log::warn!("elevated element arena occupation: {}.", percentage);
1436            }
1437            element_arena.clear();
1438        });
1439
1440        self.window.draw_phase = DrawPhase::Focus;
1441        let previous_focus_path = self.window.rendered_frame.focus_path();
1442        let previous_window_active = self.window.rendered_frame.window_active;
1443        mem::swap(&mut self.window.rendered_frame, &mut self.window.next_frame);
1444        self.window.next_frame.clear();
1445        let current_focus_path = self.window.rendered_frame.focus_path();
1446        let current_window_active = self.window.rendered_frame.window_active;
1447
1448        if previous_focus_path != current_focus_path
1449            || previous_window_active != current_window_active
1450        {
1451            if !previous_focus_path.is_empty() && current_focus_path.is_empty() {
1452                self.window
1453                    .focus_lost_listeners
1454                    .clone()
1455                    .retain(&(), |listener| listener(self));
1456            }
1457
1458            let event = WindowFocusEvent {
1459                previous_focus_path: if previous_window_active {
1460                    previous_focus_path
1461                } else {
1462                    Default::default()
1463                },
1464                current_focus_path: if current_window_active {
1465                    current_focus_path
1466                } else {
1467                    Default::default()
1468                },
1469            };
1470            self.window
1471                .focus_listeners
1472                .clone()
1473                .retain(&(), |listener| listener(&event, self));
1474        }
1475
1476        self.reset_cursor_style();
1477        self.window.refreshing = false;
1478        self.window.draw_phase = DrawPhase::None;
1479        self.window.needs_present.set(true);
1480    }
1481
1482    #[profiling::function]
1483    fn present(&self) {
1484        self.window
1485            .platform_window
1486            .draw(&self.window.rendered_frame.scene);
1487        self.window.needs_present.set(false);
1488        profiling::finish_frame!();
1489    }
1490
1491    fn draw_roots(&mut self) {
1492        self.window.draw_phase = DrawPhase::Prepaint;
1493        self.window.tooltip_bounds.take();
1494
1495        // Layout all root elements.
1496        let mut root_element = self.window.root_view.as_ref().unwrap().clone().into_any();
1497        root_element.prepaint_as_root(Point::default(), self.window.viewport_size.into(), self);
1498
1499        let mut sorted_deferred_draws =
1500            (0..self.window.next_frame.deferred_draws.len()).collect::<SmallVec<[_; 8]>>();
1501        sorted_deferred_draws.sort_by_key(|ix| self.window.next_frame.deferred_draws[*ix].priority);
1502        self.prepaint_deferred_draws(&sorted_deferred_draws);
1503
1504        let mut prompt_element = None;
1505        let mut active_drag_element = None;
1506        let mut tooltip_element = None;
1507        if let Some(prompt) = self.window.prompt.take() {
1508            let mut element = prompt.view.any_view().into_any();
1509            element.prepaint_as_root(Point::default(), self.window.viewport_size.into(), self);
1510            prompt_element = Some(element);
1511            self.window.prompt = Some(prompt);
1512        } else if let Some(active_drag) = self.app.active_drag.take() {
1513            let mut element = active_drag.view.clone().into_any();
1514            let offset = self.mouse_position() - active_drag.cursor_offset;
1515            element.prepaint_as_root(offset, AvailableSpace::min_size(), self);
1516            active_drag_element = Some(element);
1517            self.app.active_drag = Some(active_drag);
1518        } else {
1519            tooltip_element = self.prepaint_tooltip();
1520        }
1521
1522        self.window.mouse_hit_test = self.window.next_frame.hit_test(self.window.mouse_position);
1523
1524        // Now actually paint the elements.
1525        self.window.draw_phase = DrawPhase::Paint;
1526        root_element.paint(self);
1527
1528        self.paint_deferred_draws(&sorted_deferred_draws);
1529
1530        if let Some(mut prompt_element) = prompt_element {
1531            prompt_element.paint(self);
1532        } else if let Some(mut drag_element) = active_drag_element {
1533            drag_element.paint(self);
1534        } else if let Some(mut tooltip_element) = tooltip_element {
1535            tooltip_element.paint(self);
1536        }
1537    }
1538
1539    fn prepaint_tooltip(&mut self) -> Option<AnyElement> {
1540        let tooltip_request = self.window.next_frame.tooltip_requests.last().cloned()?;
1541        let tooltip_request = tooltip_request.unwrap();
1542        let mut element = tooltip_request.tooltip.view.clone().into_any();
1543        let mouse_position = tooltip_request.tooltip.mouse_position;
1544        let tooltip_size = element.layout_as_root(AvailableSpace::min_size(), self);
1545
1546        let mut tooltip_bounds = Bounds::new(mouse_position + point(px(1.), px(1.)), tooltip_size);
1547        let window_bounds = Bounds {
1548            origin: Point::default(),
1549            size: self.viewport_size(),
1550        };
1551
1552        if tooltip_bounds.right() > window_bounds.right() {
1553            let new_x = mouse_position.x - tooltip_bounds.size.width - px(1.);
1554            if new_x >= Pixels::ZERO {
1555                tooltip_bounds.origin.x = new_x;
1556            } else {
1557                tooltip_bounds.origin.x = cmp::max(
1558                    Pixels::ZERO,
1559                    tooltip_bounds.origin.x - tooltip_bounds.right() - window_bounds.right(),
1560                );
1561            }
1562        }
1563
1564        if tooltip_bounds.bottom() > window_bounds.bottom() {
1565            let new_y = mouse_position.y - tooltip_bounds.size.height - px(1.);
1566            if new_y >= Pixels::ZERO {
1567                tooltip_bounds.origin.y = new_y;
1568            } else {
1569                tooltip_bounds.origin.y = cmp::max(
1570                    Pixels::ZERO,
1571                    tooltip_bounds.origin.y - tooltip_bounds.bottom() - window_bounds.bottom(),
1572                );
1573            }
1574        }
1575
1576        self.with_absolute_element_offset(tooltip_bounds.origin, |cx| element.prepaint(cx));
1577
1578        self.window.tooltip_bounds = Some(TooltipBounds {
1579            id: tooltip_request.id,
1580            bounds: tooltip_bounds,
1581        });
1582        Some(element)
1583    }
1584
1585    fn prepaint_deferred_draws(&mut self, deferred_draw_indices: &[usize]) {
1586        assert_eq!(self.window.element_id_stack.len(), 0);
1587
1588        let mut deferred_draws = mem::take(&mut self.window.next_frame.deferred_draws);
1589        for deferred_draw_ix in deferred_draw_indices {
1590            let deferred_draw = &mut deferred_draws[*deferred_draw_ix];
1591            self.window
1592                .element_id_stack
1593                .clone_from(&deferred_draw.element_id_stack);
1594            self.window
1595                .text_style_stack
1596                .clone_from(&deferred_draw.text_style_stack);
1597            self.window
1598                .next_frame
1599                .dispatch_tree
1600                .set_active_node(deferred_draw.parent_node);
1601
1602            let prepaint_start = self.prepaint_index();
1603            if let Some(element) = deferred_draw.element.as_mut() {
1604                self.with_absolute_element_offset(deferred_draw.absolute_offset, |cx| {
1605                    element.prepaint(cx)
1606                });
1607            } else {
1608                self.reuse_prepaint(deferred_draw.prepaint_range.clone());
1609            }
1610            let prepaint_end = self.prepaint_index();
1611            deferred_draw.prepaint_range = prepaint_start..prepaint_end;
1612        }
1613        assert_eq!(
1614            self.window.next_frame.deferred_draws.len(),
1615            0,
1616            "cannot call defer_draw during deferred drawing"
1617        );
1618        self.window.next_frame.deferred_draws = deferred_draws;
1619        self.window.element_id_stack.clear();
1620        self.window.text_style_stack.clear();
1621    }
1622
1623    fn paint_deferred_draws(&mut self, deferred_draw_indices: &[usize]) {
1624        assert_eq!(self.window.element_id_stack.len(), 0);
1625
1626        let mut deferred_draws = mem::take(&mut self.window.next_frame.deferred_draws);
1627        for deferred_draw_ix in deferred_draw_indices {
1628            let mut deferred_draw = &mut deferred_draws[*deferred_draw_ix];
1629            self.window
1630                .element_id_stack
1631                .clone_from(&deferred_draw.element_id_stack);
1632            self.window
1633                .next_frame
1634                .dispatch_tree
1635                .set_active_node(deferred_draw.parent_node);
1636
1637            let paint_start = self.paint_index();
1638            if let Some(element) = deferred_draw.element.as_mut() {
1639                element.paint(self);
1640            } else {
1641                self.reuse_paint(deferred_draw.paint_range.clone());
1642            }
1643            let paint_end = self.paint_index();
1644            deferred_draw.paint_range = paint_start..paint_end;
1645        }
1646        self.window.next_frame.deferred_draws = deferred_draws;
1647        self.window.element_id_stack.clear();
1648    }
1649
1650    pub(crate) fn prepaint_index(&self) -> PrepaintStateIndex {
1651        PrepaintStateIndex {
1652            hitboxes_index: self.window.next_frame.hitboxes.len(),
1653            tooltips_index: self.window.next_frame.tooltip_requests.len(),
1654            deferred_draws_index: self.window.next_frame.deferred_draws.len(),
1655            dispatch_tree_index: self.window.next_frame.dispatch_tree.len(),
1656            accessed_element_states_index: self.window.next_frame.accessed_element_states.len(),
1657            line_layout_index: self.window.text_system.layout_index(),
1658        }
1659    }
1660
1661    pub(crate) fn reuse_prepaint(&mut self, range: Range<PrepaintStateIndex>) {
1662        let window = &mut self.window;
1663        window.next_frame.hitboxes.extend(
1664            window.rendered_frame.hitboxes[range.start.hitboxes_index..range.end.hitboxes_index]
1665                .iter()
1666                .cloned(),
1667        );
1668        window.next_frame.tooltip_requests.extend(
1669            window.rendered_frame.tooltip_requests
1670                [range.start.tooltips_index..range.end.tooltips_index]
1671                .iter_mut()
1672                .map(|request| request.take()),
1673        );
1674        window.next_frame.accessed_element_states.extend(
1675            window.rendered_frame.accessed_element_states[range.start.accessed_element_states_index
1676                ..range.end.accessed_element_states_index]
1677                .iter()
1678                .map(|(id, type_id)| (GlobalElementId(id.0.clone()), *type_id)),
1679        );
1680        window
1681            .text_system
1682            .reuse_layouts(range.start.line_layout_index..range.end.line_layout_index);
1683
1684        let reused_subtree = window.next_frame.dispatch_tree.reuse_subtree(
1685            range.start.dispatch_tree_index..range.end.dispatch_tree_index,
1686            &mut window.rendered_frame.dispatch_tree,
1687            window.focus,
1688        );
1689
1690        if reused_subtree.contains_focus() {
1691            window.next_frame.focus = window.focus;
1692        }
1693
1694        window.next_frame.deferred_draws.extend(
1695            window.rendered_frame.deferred_draws
1696                [range.start.deferred_draws_index..range.end.deferred_draws_index]
1697                .iter()
1698                .map(|deferred_draw| DeferredDraw {
1699                    parent_node: reused_subtree.refresh_node_id(deferred_draw.parent_node),
1700                    element_id_stack: deferred_draw.element_id_stack.clone(),
1701                    text_style_stack: deferred_draw.text_style_stack.clone(),
1702                    priority: deferred_draw.priority,
1703                    element: None,
1704                    absolute_offset: deferred_draw.absolute_offset,
1705                    prepaint_range: deferred_draw.prepaint_range.clone(),
1706                    paint_range: deferred_draw.paint_range.clone(),
1707                }),
1708        );
1709    }
1710
1711    pub(crate) fn paint_index(&self) -> PaintIndex {
1712        PaintIndex {
1713            scene_index: self.window.next_frame.scene.len(),
1714            mouse_listeners_index: self.window.next_frame.mouse_listeners.len(),
1715            input_handlers_index: self.window.next_frame.input_handlers.len(),
1716            cursor_styles_index: self.window.next_frame.cursor_styles.len(),
1717            accessed_element_states_index: self.window.next_frame.accessed_element_states.len(),
1718            line_layout_index: self.window.text_system.layout_index(),
1719        }
1720    }
1721
1722    pub(crate) fn reuse_paint(&mut self, range: Range<PaintIndex>) {
1723        let window = &mut self.window;
1724
1725        window.next_frame.cursor_styles.extend(
1726            window.rendered_frame.cursor_styles
1727                [range.start.cursor_styles_index..range.end.cursor_styles_index]
1728                .iter()
1729                .cloned(),
1730        );
1731        window.next_frame.input_handlers.extend(
1732            window.rendered_frame.input_handlers
1733                [range.start.input_handlers_index..range.end.input_handlers_index]
1734                .iter_mut()
1735                .map(|handler| handler.take()),
1736        );
1737        window.next_frame.mouse_listeners.extend(
1738            window.rendered_frame.mouse_listeners
1739                [range.start.mouse_listeners_index..range.end.mouse_listeners_index]
1740                .iter_mut()
1741                .map(|listener| listener.take()),
1742        );
1743        window.next_frame.accessed_element_states.extend(
1744            window.rendered_frame.accessed_element_states[range.start.accessed_element_states_index
1745                ..range.end.accessed_element_states_index]
1746                .iter()
1747                .map(|(id, type_id)| (GlobalElementId(id.0.clone()), *type_id)),
1748        );
1749        window
1750            .text_system
1751            .reuse_layouts(range.start.line_layout_index..range.end.line_layout_index);
1752        window.next_frame.scene.replay(
1753            range.start.scene_index..range.end.scene_index,
1754            &window.rendered_frame.scene,
1755        );
1756    }
1757
1758    /// Push a text style onto the stack, and call a function with that style active.
1759    /// Use [`AppContext::text_style`] to get the current, combined text style. This method
1760    /// should only be called as part of element drawing.
1761    pub fn with_text_style<F, R>(&mut self, style: Option<TextStyleRefinement>, f: F) -> R
1762    where
1763        F: FnOnce(&mut Self) -> R,
1764    {
1765        debug_assert!(
1766            matches!(
1767                self.window.draw_phase,
1768                DrawPhase::Prepaint | DrawPhase::Paint
1769            ),
1770            "this method can only be called during request_layout, prepaint, or paint"
1771        );
1772        if let Some(style) = style {
1773            self.window.text_style_stack.push(style);
1774            let result = f(self);
1775            self.window.text_style_stack.pop();
1776            result
1777        } else {
1778            f(self)
1779        }
1780    }
1781
1782    /// Updates the cursor style at the platform level. This method should only be called
1783    /// during the prepaint phase of element drawing.
1784    pub fn set_cursor_style(&mut self, style: CursorStyle, hitbox: &Hitbox) {
1785        debug_assert_eq!(
1786            self.window.draw_phase,
1787            DrawPhase::Paint,
1788            "this method can only be called during paint"
1789        );
1790        self.window
1791            .next_frame
1792            .cursor_styles
1793            .push(CursorStyleRequest {
1794                hitbox_id: hitbox.id,
1795                style,
1796            });
1797    }
1798
1799    /// Sets a tooltip to be rendered for the upcoming frame. This method should only be called
1800    /// during the paint phase of element drawing.
1801    pub fn set_tooltip(&mut self, tooltip: AnyTooltip) -> TooltipId {
1802        debug_assert_eq!(
1803            self.window.draw_phase,
1804            DrawPhase::Prepaint,
1805            "this method can only be called during prepaint"
1806        );
1807        let id = TooltipId(post_inc(&mut self.window.next_tooltip_id.0));
1808        self.window
1809            .next_frame
1810            .tooltip_requests
1811            .push(Some(TooltipRequest { id, tooltip }));
1812        id
1813    }
1814
1815    /// Invoke the given function with the given content mask after intersecting it
1816    /// with the current mask. This method should only be called during element drawing.
1817    pub fn with_content_mask<R>(
1818        &mut self,
1819        mask: Option<ContentMask<Pixels>>,
1820        f: impl FnOnce(&mut Self) -> R,
1821    ) -> R {
1822        debug_assert!(
1823            matches!(
1824                self.window.draw_phase,
1825                DrawPhase::Prepaint | DrawPhase::Paint
1826            ),
1827            "this method can only be called during request_layout, prepaint, or paint"
1828        );
1829        if let Some(mask) = mask {
1830            let mask = mask.intersect(&self.content_mask());
1831            self.window_mut().content_mask_stack.push(mask);
1832            let result = f(self);
1833            self.window_mut().content_mask_stack.pop();
1834            result
1835        } else {
1836            f(self)
1837        }
1838    }
1839
1840    /// Updates the global element offset relative to the current offset. This is used to implement
1841    /// scrolling. This method should only be called during the prepaint phase of element drawing.
1842    pub fn with_element_offset<R>(
1843        &mut self,
1844        offset: Point<Pixels>,
1845        f: impl FnOnce(&mut Self) -> R,
1846    ) -> R {
1847        debug_assert_eq!(
1848            self.window.draw_phase,
1849            DrawPhase::Prepaint,
1850            "this method can only be called during request_layout, or prepaint"
1851        );
1852
1853        if offset.is_zero() {
1854            return f(self);
1855        };
1856
1857        let abs_offset = self.element_offset() + offset;
1858        self.with_absolute_element_offset(abs_offset, f)
1859    }
1860
1861    /// Updates the global element offset based on the given offset. This is used to implement
1862    /// drag handles and other manual painting of elements. This method should only be called during
1863    /// the prepaint phase of element drawing.
1864    pub fn with_absolute_element_offset<R>(
1865        &mut self,
1866        offset: Point<Pixels>,
1867        f: impl FnOnce(&mut Self) -> R,
1868    ) -> R {
1869        debug_assert_eq!(
1870            self.window.draw_phase,
1871            DrawPhase::Prepaint,
1872            "this method can only be called during request_layout, or prepaint"
1873        );
1874        self.window_mut().element_offset_stack.push(offset);
1875        let result = f(self);
1876        self.window_mut().element_offset_stack.pop();
1877        result
1878    }
1879
1880    /// Perform prepaint on child elements in a "retryable" manner, so that any side effects
1881    /// of prepaints can be discarded before prepainting again. This is used to support autoscroll
1882    /// where we need to prepaint children to detect the autoscroll bounds, then adjust the
1883    /// element offset and prepaint again. See [`List`] for an example. This method should only be
1884    /// called during the prepaint phase of element drawing.
1885    pub fn transact<T, U>(&mut self, f: impl FnOnce(&mut Self) -> Result<T, U>) -> Result<T, U> {
1886        debug_assert_eq!(
1887            self.window.draw_phase,
1888            DrawPhase::Prepaint,
1889            "this method can only be called during prepaint"
1890        );
1891        let index = self.prepaint_index();
1892        let result = f(self);
1893        if result.is_err() {
1894            self.window
1895                .next_frame
1896                .hitboxes
1897                .truncate(index.hitboxes_index);
1898            self.window
1899                .next_frame
1900                .tooltip_requests
1901                .truncate(index.tooltips_index);
1902            self.window
1903                .next_frame
1904                .deferred_draws
1905                .truncate(index.deferred_draws_index);
1906            self.window
1907                .next_frame
1908                .dispatch_tree
1909                .truncate(index.dispatch_tree_index);
1910            self.window
1911                .next_frame
1912                .accessed_element_states
1913                .truncate(index.accessed_element_states_index);
1914            self.window
1915                .text_system
1916                .truncate_layouts(index.line_layout_index);
1917        }
1918        result
1919    }
1920
1921    /// When you call this method during [`prepaint`], containing elements will attempt to
1922    /// scroll to cause the specified bounds to become visible. When they decide to autoscroll, they will call
1923    /// [`prepaint`] again with a new set of bounds. See [`List`] for an example of an element
1924    /// that supports this method being called on the elements it contains. This method should only be
1925    /// called during the prepaint phase of element drawing.
1926    pub fn request_autoscroll(&mut self, bounds: Bounds<Pixels>) {
1927        debug_assert_eq!(
1928            self.window.draw_phase,
1929            DrawPhase::Prepaint,
1930            "this method can only be called during prepaint"
1931        );
1932        self.window.requested_autoscroll = Some(bounds);
1933    }
1934
1935    /// This method can be called from a containing element such as [`List`] to support the autoscroll behavior
1936    /// described in [`request_autoscroll`].
1937    pub fn take_autoscroll(&mut self) -> Option<Bounds<Pixels>> {
1938        debug_assert_eq!(
1939            self.window.draw_phase,
1940            DrawPhase::Prepaint,
1941            "this method can only be called during prepaint"
1942        );
1943        self.window.requested_autoscroll.take()
1944    }
1945
1946    /// Remove an asset from GPUI's cache
1947    pub fn remove_cached_asset<A: Asset + 'static>(
1948        &mut self,
1949        source: &A::Source,
1950    ) -> Option<A::Output> {
1951        self.asset_cache.remove::<A>(source)
1952    }
1953
1954    /// Asynchronously load an asset, if the asset hasn't finished loading this will return None.
1955    /// Your view will be re-drawn once the asset has finished loading.
1956    ///
1957    /// Note that the multiple calls to this method will only result in one `Asset::load` call.
1958    /// The results of that call will be cached, and returned on subsequent uses of this API.
1959    ///
1960    /// Use [Self::remove_cached_asset] to reload your asset.
1961    pub fn use_cached_asset<A: Asset + 'static>(
1962        &mut self,
1963        source: &A::Source,
1964    ) -> Option<A::Output> {
1965        self.asset_cache.get::<A>(source).or_else(|| {
1966            if let Some(asset) = self.use_asset::<A>(source) {
1967                self.asset_cache
1968                    .insert::<A>(source.to_owned(), asset.clone());
1969                Some(asset)
1970            } else {
1971                None
1972            }
1973        })
1974    }
1975
1976    /// Asynchronously load an asset, if the asset hasn't finished loading this will return None.
1977    /// Your view will be re-drawn once the asset has finished loading.
1978    ///
1979    /// Note that the multiple calls to this method will only result in one `Asset::load` call at a
1980    /// time.
1981    ///
1982    /// This asset will not be cached by default, see [Self::use_cached_asset]
1983    pub fn use_asset<A: Asset + 'static>(&mut self, source: &A::Source) -> Option<A::Output> {
1984        let asset_id = (TypeId::of::<A>(), hash(source));
1985        let mut is_first = false;
1986        let task = self
1987            .loading_assets
1988            .remove(&asset_id)
1989            .map(|boxed_task| *boxed_task.downcast::<Shared<Task<A::Output>>>().unwrap())
1990            .unwrap_or_else(|| {
1991                is_first = true;
1992                let future = A::load(source.clone(), self);
1993                let task = self.background_executor().spawn(future).shared();
1994                task
1995            });
1996
1997        task.clone().now_or_never().or_else(|| {
1998            if is_first {
1999                let parent_id = self.parent_view_id();
2000                self.spawn({
2001                    let task = task.clone();
2002                    |mut cx| async move {
2003                        task.await;
2004
2005                        cx.on_next_frame(move |cx| {
2006                            if let Some(parent_id) = parent_id {
2007                                cx.notify(parent_id)
2008                            } else {
2009                                cx.refresh()
2010                            }
2011                        });
2012                    }
2013                })
2014                .detach();
2015            }
2016
2017            self.loading_assets.insert(asset_id, Box::new(task));
2018
2019            None
2020        })
2021    }
2022
2023    /// Obtain the current element offset. This method should only be called during the
2024    /// prepaint phase of element drawing.
2025    pub fn element_offset(&self) -> Point<Pixels> {
2026        debug_assert_eq!(
2027            self.window.draw_phase,
2028            DrawPhase::Prepaint,
2029            "this method can only be called during prepaint"
2030        );
2031        self.window()
2032            .element_offset_stack
2033            .last()
2034            .copied()
2035            .unwrap_or_default()
2036    }
2037
2038    /// Obtain the current content mask. This method should only be called during element drawing.
2039    pub fn content_mask(&self) -> ContentMask<Pixels> {
2040        debug_assert!(
2041            matches!(
2042                self.window.draw_phase,
2043                DrawPhase::Prepaint | DrawPhase::Paint
2044            ),
2045            "this method can only be called during prepaint, or paint"
2046        );
2047        self.window()
2048            .content_mask_stack
2049            .last()
2050            .cloned()
2051            .unwrap_or_else(|| ContentMask {
2052                bounds: Bounds {
2053                    origin: Point::default(),
2054                    size: self.window().viewport_size,
2055                },
2056            })
2057    }
2058
2059    /// Provide elements in the called function with a new namespace in which their identiers must be unique.
2060    /// This can be used within a custom element to distinguish multiple sets of child elements.
2061    pub fn with_element_namespace<R>(
2062        &mut self,
2063        element_id: impl Into<ElementId>,
2064        f: impl FnOnce(&mut Self) -> R,
2065    ) -> R {
2066        self.window.element_id_stack.push(element_id.into());
2067        let result = f(self);
2068        self.window.element_id_stack.pop();
2069        result
2070    }
2071
2072    /// Updates or initializes state for an element with the given id that lives across multiple
2073    /// frames. If an element with this ID existed in the rendered frame, its state will be passed
2074    /// to the given closure. The state returned by the closure will be stored so it can be referenced
2075    /// when drawing the next frame. This method should only be called as part of element drawing.
2076    pub fn with_element_state<S, R>(
2077        &mut self,
2078        global_id: &GlobalElementId,
2079        f: impl FnOnce(Option<S>, &mut Self) -> (R, S),
2080    ) -> R
2081    where
2082        S: 'static,
2083    {
2084        debug_assert!(
2085            matches!(
2086                self.window.draw_phase,
2087                DrawPhase::Prepaint | DrawPhase::Paint
2088            ),
2089            "this method can only be called during request_layout, prepaint, or paint"
2090        );
2091
2092        let key = (GlobalElementId(global_id.0.clone()), TypeId::of::<S>());
2093        self.window
2094            .next_frame
2095            .accessed_element_states
2096            .push((GlobalElementId(key.0.clone()), TypeId::of::<S>()));
2097
2098        if let Some(any) = self
2099            .window
2100            .next_frame
2101            .element_states
2102            .remove(&key)
2103            .or_else(|| self.window.rendered_frame.element_states.remove(&key))
2104        {
2105            let ElementStateBox {
2106                inner,
2107                #[cfg(debug_assertions)]
2108                type_name,
2109            } = any;
2110            // Using the extra inner option to avoid needing to reallocate a new box.
2111            let mut state_box = inner
2112                .downcast::<Option<S>>()
2113                .map_err(|_| {
2114                    #[cfg(debug_assertions)]
2115                    {
2116                        anyhow::anyhow!(
2117                            "invalid element state type for id, requested {:?}, actual: {:?}",
2118                            std::any::type_name::<S>(),
2119                            type_name
2120                        )
2121                    }
2122
2123                    #[cfg(not(debug_assertions))]
2124                    {
2125                        anyhow::anyhow!(
2126                            "invalid element state type for id, requested {:?}",
2127                            std::any::type_name::<S>(),
2128                        )
2129                    }
2130                })
2131                .unwrap();
2132
2133            let state = state_box.take().expect(
2134                "reentrant call to with_element_state for the same state type and element id",
2135            );
2136            let (result, state) = f(Some(state), self);
2137            state_box.replace(state);
2138            self.window.next_frame.element_states.insert(
2139                key,
2140                ElementStateBox {
2141                    inner: state_box,
2142                    #[cfg(debug_assertions)]
2143                    type_name,
2144                },
2145            );
2146            result
2147        } else {
2148            let (result, state) = f(None, self);
2149            self.window.next_frame.element_states.insert(
2150                key,
2151                ElementStateBox {
2152                    inner: Box::new(Some(state)),
2153                    #[cfg(debug_assertions)]
2154                    type_name: std::any::type_name::<S>(),
2155                },
2156            );
2157            result
2158        }
2159    }
2160
2161    /// A variant of `with_element_state` that allows the element's id to be optional. This is a convenience
2162    /// method for elements where the element id may or may not be assigned. Prefer using `with_element_state`
2163    /// when the element is guaranteed to have an id.
2164    pub fn with_optional_element_state<S, R>(
2165        &mut self,
2166        global_id: Option<&GlobalElementId>,
2167        f: impl FnOnce(Option<Option<S>>, &mut Self) -> (R, Option<S>),
2168    ) -> R
2169    where
2170        S: 'static,
2171    {
2172        debug_assert!(
2173            matches!(
2174                self.window.draw_phase,
2175                DrawPhase::Prepaint | DrawPhase::Paint
2176            ),
2177            "this method can only be called during request_layout, prepaint, or paint"
2178        );
2179
2180        if let Some(global_id) = global_id {
2181            self.with_element_state(global_id, |state, cx| {
2182                let (result, state) = f(Some(state), cx);
2183                let state =
2184                    state.expect("you must return some state when you pass some element id");
2185                (result, state)
2186            })
2187        } else {
2188            let (result, state) = f(None, self);
2189            debug_assert!(
2190                state.is_none(),
2191                "you must not return an element state when passing None for the global id"
2192            );
2193            result
2194        }
2195    }
2196
2197    /// Defers the drawing of the given element, scheduling it to be painted on top of the currently-drawn tree
2198    /// at a later time. The `priority` parameter determines the drawing order relative to other deferred elements,
2199    /// with higher values being drawn on top.
2200    ///
2201    /// This method should only be called as part of the prepaint phase of element drawing.
2202    pub fn defer_draw(
2203        &mut self,
2204        element: AnyElement,
2205        absolute_offset: Point<Pixels>,
2206        priority: usize,
2207    ) {
2208        let window = &mut self.window;
2209        debug_assert_eq!(
2210            window.draw_phase,
2211            DrawPhase::Prepaint,
2212            "this method can only be called during request_layout or prepaint"
2213        );
2214        let parent_node = window.next_frame.dispatch_tree.active_node_id().unwrap();
2215        window.next_frame.deferred_draws.push(DeferredDraw {
2216            parent_node,
2217            element_id_stack: window.element_id_stack.clone(),
2218            text_style_stack: window.text_style_stack.clone(),
2219            priority,
2220            element: Some(element),
2221            absolute_offset,
2222            prepaint_range: PrepaintStateIndex::default()..PrepaintStateIndex::default(),
2223            paint_range: PaintIndex::default()..PaintIndex::default(),
2224        });
2225    }
2226
2227    /// Creates a new painting layer for the specified bounds. A "layer" is a batch
2228    /// of geometry that are non-overlapping and have the same draw order. This is typically used
2229    /// for performance reasons.
2230    ///
2231    /// This method should only be called as part of the paint phase of element drawing.
2232    pub fn paint_layer<R>(&mut self, bounds: Bounds<Pixels>, f: impl FnOnce(&mut Self) -> R) -> R {
2233        debug_assert_eq!(
2234            self.window.draw_phase,
2235            DrawPhase::Paint,
2236            "this method can only be called during paint"
2237        );
2238
2239        let scale_factor = self.scale_factor();
2240        let content_mask = self.content_mask();
2241        let clipped_bounds = bounds.intersect(&content_mask.bounds);
2242        if !clipped_bounds.is_empty() {
2243            self.window
2244                .next_frame
2245                .scene
2246                .push_layer(clipped_bounds.scale(scale_factor));
2247        }
2248
2249        let result = f(self);
2250
2251        if !clipped_bounds.is_empty() {
2252            self.window.next_frame.scene.pop_layer();
2253        }
2254
2255        result
2256    }
2257
2258    /// Paint one or more drop shadows into the scene for the next frame at the current z-index.
2259    ///
2260    /// This method should only be called as part of the paint phase of element drawing.
2261    pub fn paint_shadows(
2262        &mut self,
2263        bounds: Bounds<Pixels>,
2264        corner_radii: Corners<Pixels>,
2265        shadows: &[BoxShadow],
2266    ) {
2267        debug_assert_eq!(
2268            self.window.draw_phase,
2269            DrawPhase::Paint,
2270            "this method can only be called during paint"
2271        );
2272
2273        let scale_factor = self.scale_factor();
2274        let content_mask = self.content_mask();
2275        for shadow in shadows {
2276            let mut shadow_bounds = bounds;
2277            shadow_bounds.origin += shadow.offset;
2278            shadow_bounds.dilate(shadow.spread_radius);
2279            self.window.next_frame.scene.insert_primitive(Shadow {
2280                order: 0,
2281                blur_radius: shadow.blur_radius.scale(scale_factor),
2282                bounds: shadow_bounds.scale(scale_factor),
2283                content_mask: content_mask.scale(scale_factor),
2284                corner_radii: corner_radii.scale(scale_factor),
2285                color: shadow.color,
2286            });
2287        }
2288    }
2289
2290    /// Paint one or more quads into the scene for the next frame at the current stacking context.
2291    /// Quads are colored rectangular regions with an optional background, border, and corner radius.
2292    /// see [`fill`](crate::fill), [`outline`](crate::outline), and [`quad`](crate::quad) to construct this type.
2293    ///
2294    /// This method should only be called as part of the paint phase of element drawing.
2295    pub fn paint_quad(&mut self, quad: PaintQuad) {
2296        debug_assert_eq!(
2297            self.window.draw_phase,
2298            DrawPhase::Paint,
2299            "this method can only be called during paint"
2300        );
2301
2302        let scale_factor = self.scale_factor();
2303        let content_mask = self.content_mask();
2304        self.window.next_frame.scene.insert_primitive(Quad {
2305            order: 0,
2306            pad: 0,
2307            bounds: quad.bounds.scale(scale_factor),
2308            content_mask: content_mask.scale(scale_factor),
2309            background: quad.background,
2310            border_color: quad.border_color,
2311            corner_radii: quad.corner_radii.scale(scale_factor),
2312            border_widths: quad.border_widths.scale(scale_factor),
2313        });
2314    }
2315
2316    /// Paint the given `Path` into the scene for the next frame at the current z-index.
2317    ///
2318    /// This method should only be called as part of the paint phase of element drawing.
2319    pub fn paint_path(&mut self, mut path: Path<Pixels>, color: impl Into<Hsla>) {
2320        debug_assert_eq!(
2321            self.window.draw_phase,
2322            DrawPhase::Paint,
2323            "this method can only be called during paint"
2324        );
2325
2326        let scale_factor = self.scale_factor();
2327        let content_mask = self.content_mask();
2328        path.content_mask = content_mask;
2329        path.color = color.into();
2330        self.window
2331            .next_frame
2332            .scene
2333            .insert_primitive(path.scale(scale_factor));
2334    }
2335
2336    /// Paint an underline into the scene for the next frame at the current z-index.
2337    ///
2338    /// This method should only be called as part of the paint phase of element drawing.
2339    pub fn paint_underline(
2340        &mut self,
2341        origin: Point<Pixels>,
2342        width: Pixels,
2343        style: &UnderlineStyle,
2344    ) {
2345        debug_assert_eq!(
2346            self.window.draw_phase,
2347            DrawPhase::Paint,
2348            "this method can only be called during paint"
2349        );
2350
2351        let scale_factor = self.scale_factor();
2352        let height = if style.wavy {
2353            style.thickness * 3.
2354        } else {
2355            style.thickness
2356        };
2357        let bounds = Bounds {
2358            origin,
2359            size: size(width, height),
2360        };
2361        let content_mask = self.content_mask();
2362
2363        self.window.next_frame.scene.insert_primitive(Underline {
2364            order: 0,
2365            pad: 0,
2366            bounds: bounds.scale(scale_factor),
2367            content_mask: content_mask.scale(scale_factor),
2368            color: style.color.unwrap_or_default(),
2369            thickness: style.thickness.scale(scale_factor),
2370            wavy: style.wavy,
2371        });
2372    }
2373
2374    /// Paint a strikethrough into the scene for the next frame at the current z-index.
2375    ///
2376    /// This method should only be called as part of the paint phase of element drawing.
2377    pub fn paint_strikethrough(
2378        &mut self,
2379        origin: Point<Pixels>,
2380        width: Pixels,
2381        style: &StrikethroughStyle,
2382    ) {
2383        debug_assert_eq!(
2384            self.window.draw_phase,
2385            DrawPhase::Paint,
2386            "this method can only be called during paint"
2387        );
2388
2389        let scale_factor = self.scale_factor();
2390        let height = style.thickness;
2391        let bounds = Bounds {
2392            origin,
2393            size: size(width, height),
2394        };
2395        let content_mask = self.content_mask();
2396
2397        self.window.next_frame.scene.insert_primitive(Underline {
2398            order: 0,
2399            pad: 0,
2400            bounds: bounds.scale(scale_factor),
2401            content_mask: content_mask.scale(scale_factor),
2402            thickness: style.thickness.scale(scale_factor),
2403            color: style.color.unwrap_or_default(),
2404            wavy: false,
2405        });
2406    }
2407
2408    /// Paints a monochrome (non-emoji) glyph into the scene for the next frame at the current z-index.
2409    ///
2410    /// The y component of the origin is the baseline of the glyph.
2411    /// You should generally prefer to use the [`ShapedLine::paint`](crate::ShapedLine::paint) or
2412    /// [`WrappedLine::paint`](crate::WrappedLine::paint) methods in the [`TextSystem`](crate::TextSystem).
2413    /// This method is only useful if you need to paint a single glyph that has already been shaped.
2414    ///
2415    /// This method should only be called as part of the paint phase of element drawing.
2416    pub fn paint_glyph(
2417        &mut self,
2418        origin: Point<Pixels>,
2419        font_id: FontId,
2420        glyph_id: GlyphId,
2421        font_size: Pixels,
2422        color: Hsla,
2423    ) -> Result<()> {
2424        debug_assert_eq!(
2425            self.window.draw_phase,
2426            DrawPhase::Paint,
2427            "this method can only be called during paint"
2428        );
2429
2430        let scale_factor = self.scale_factor();
2431        let glyph_origin = origin.scale(scale_factor);
2432        let subpixel_variant = Point {
2433            x: (glyph_origin.x.0.fract() * SUBPIXEL_VARIANTS as f32).floor() as u8,
2434            y: (glyph_origin.y.0.fract() * SUBPIXEL_VARIANTS as f32).floor() as u8,
2435        };
2436        let params = RenderGlyphParams {
2437            font_id,
2438            glyph_id,
2439            font_size,
2440            subpixel_variant,
2441            scale_factor,
2442            is_emoji: false,
2443        };
2444
2445        let raster_bounds = self.text_system().raster_bounds(&params)?;
2446        if !raster_bounds.is_zero() {
2447            let tile = self
2448                .window
2449                .sprite_atlas
2450                .get_or_insert_with(&params.clone().into(), &mut || {
2451                    let (size, bytes) = self.text_system().rasterize_glyph(&params)?;
2452                    Ok(Some((size, Cow::Owned(bytes))))
2453                })?
2454                .expect("Callback above only errors or returns Some");
2455            let bounds = Bounds {
2456                origin: glyph_origin.map(|px| px.floor()) + raster_bounds.origin.map(Into::into),
2457                size: tile.bounds.size.map(Into::into),
2458            };
2459            let content_mask = self.content_mask().scale(scale_factor);
2460            self.window
2461                .next_frame
2462                .scene
2463                .insert_primitive(MonochromeSprite {
2464                    order: 0,
2465                    pad: 0,
2466                    bounds,
2467                    content_mask,
2468                    color,
2469                    tile,
2470                    transformation: TransformationMatrix::unit(),
2471                });
2472        }
2473        Ok(())
2474    }
2475
2476    /// Paints an emoji glyph into the scene for the next frame at the current z-index.
2477    ///
2478    /// The y component of the origin is the baseline of the glyph.
2479    /// You should generally prefer to use the [`ShapedLine::paint`](crate::ShapedLine::paint) or
2480    /// [`WrappedLine::paint`](crate::WrappedLine::paint) methods in the [`TextSystem`](crate::TextSystem).
2481    /// This method is only useful if you need to paint a single emoji that has already been shaped.
2482    ///
2483    /// This method should only be called as part of the paint phase of element drawing.
2484    pub fn paint_emoji(
2485        &mut self,
2486        origin: Point<Pixels>,
2487        font_id: FontId,
2488        glyph_id: GlyphId,
2489        font_size: Pixels,
2490    ) -> Result<()> {
2491        debug_assert_eq!(
2492            self.window.draw_phase,
2493            DrawPhase::Paint,
2494            "this method can only be called during paint"
2495        );
2496
2497        let scale_factor = self.scale_factor();
2498        let glyph_origin = origin.scale(scale_factor);
2499        let params = RenderGlyphParams {
2500            font_id,
2501            glyph_id,
2502            font_size,
2503            // We don't render emojis with subpixel variants.
2504            subpixel_variant: Default::default(),
2505            scale_factor,
2506            is_emoji: true,
2507        };
2508
2509        let raster_bounds = self.text_system().raster_bounds(&params)?;
2510        if !raster_bounds.is_zero() {
2511            let tile = self
2512                .window
2513                .sprite_atlas
2514                .get_or_insert_with(&params.clone().into(), &mut || {
2515                    let (size, bytes) = self.text_system().rasterize_glyph(&params)?;
2516                    Ok(Some((size, Cow::Owned(bytes))))
2517                })?
2518                .expect("Callback above only errors or returns Some");
2519
2520            let bounds = Bounds {
2521                origin: glyph_origin.map(|px| px.floor()) + raster_bounds.origin.map(Into::into),
2522                size: tile.bounds.size.map(Into::into),
2523            };
2524            let content_mask = self.content_mask().scale(scale_factor);
2525
2526            self.window
2527                .next_frame
2528                .scene
2529                .insert_primitive(PolychromeSprite {
2530                    order: 0,
2531                    grayscale: false,
2532                    bounds,
2533                    corner_radii: Default::default(),
2534                    content_mask,
2535                    tile,
2536                });
2537        }
2538        Ok(())
2539    }
2540
2541    /// Paint a monochrome SVG into the scene for the next frame at the current stacking context.
2542    ///
2543    /// This method should only be called as part of the paint phase of element drawing.
2544    pub fn paint_svg(
2545        &mut self,
2546        bounds: Bounds<Pixels>,
2547        path: SharedString,
2548        transformation: TransformationMatrix,
2549        color: Hsla,
2550    ) -> Result<()> {
2551        debug_assert_eq!(
2552            self.window.draw_phase,
2553            DrawPhase::Paint,
2554            "this method can only be called during paint"
2555        );
2556
2557        let scale_factor = self.scale_factor();
2558        let bounds = bounds.scale(scale_factor);
2559        // Render the SVG at twice the size to get a higher quality result.
2560        let params = RenderSvgParams {
2561            path,
2562            size: bounds
2563                .size
2564                .map(|pixels| DevicePixels::from((pixels.0 * 2.).ceil() as i32)),
2565        };
2566
2567        let Some(tile) =
2568            self.window
2569                .sprite_atlas
2570                .get_or_insert_with(&params.clone().into(), &mut || {
2571                    let Some(bytes) = self.svg_renderer.render(&params)? else {
2572                        return Ok(None);
2573                    };
2574                    Ok(Some((params.size, Cow::Owned(bytes))))
2575                })?
2576        else {
2577            return Ok(());
2578        };
2579        let content_mask = self.content_mask().scale(scale_factor);
2580
2581        self.window
2582            .next_frame
2583            .scene
2584            .insert_primitive(MonochromeSprite {
2585                order: 0,
2586                pad: 0,
2587                bounds,
2588                content_mask,
2589                color,
2590                tile,
2591                transformation,
2592            });
2593
2594        Ok(())
2595    }
2596
2597    /// Paint an image into the scene for the next frame at the current z-index.
2598    ///
2599    /// This method should only be called as part of the paint phase of element drawing.
2600    pub fn paint_image(
2601        &mut self,
2602        bounds: Bounds<Pixels>,
2603        corner_radii: Corners<Pixels>,
2604        data: Arc<ImageData>,
2605        grayscale: bool,
2606    ) -> Result<()> {
2607        debug_assert_eq!(
2608            self.window.draw_phase,
2609            DrawPhase::Paint,
2610            "this method can only be called during paint"
2611        );
2612
2613        let scale_factor = self.scale_factor();
2614        let bounds = bounds.scale(scale_factor);
2615        let params = RenderImageParams { image_id: data.id };
2616
2617        let tile = self
2618            .window
2619            .sprite_atlas
2620            .get_or_insert_with(&params.clone().into(), &mut || {
2621                Ok(Some((data.size(), Cow::Borrowed(data.as_bytes()))))
2622            })?
2623            .expect("Callback above only returns Some");
2624        let content_mask = self.content_mask().scale(scale_factor);
2625        let corner_radii = corner_radii.scale(scale_factor);
2626
2627        self.window
2628            .next_frame
2629            .scene
2630            .insert_primitive(PolychromeSprite {
2631                order: 0,
2632                grayscale,
2633                bounds,
2634                content_mask,
2635                corner_radii,
2636                tile,
2637            });
2638        Ok(())
2639    }
2640
2641    /// Paint a surface into the scene for the next frame at the current z-index.
2642    ///
2643    /// This method should only be called as part of the paint phase of element drawing.
2644    #[cfg(target_os = "macos")]
2645    pub fn paint_surface(&mut self, bounds: Bounds<Pixels>, image_buffer: CVImageBuffer) {
2646        debug_assert_eq!(
2647            self.window.draw_phase,
2648            DrawPhase::Paint,
2649            "this method can only be called during paint"
2650        );
2651
2652        let scale_factor = self.scale_factor();
2653        let bounds = bounds.scale(scale_factor);
2654        let content_mask = self.content_mask().scale(scale_factor);
2655        self.window
2656            .next_frame
2657            .scene
2658            .insert_primitive(crate::Surface {
2659                order: 0,
2660                bounds,
2661                content_mask,
2662                image_buffer,
2663            });
2664    }
2665
2666    #[must_use]
2667    /// Add a node to the layout tree for the current frame. Takes the `Style` of the element for which
2668    /// layout is being requested, along with the layout ids of any children. This method is called during
2669    /// calls to the [`Element::request_layout`] trait method and enables any element to participate in layout.
2670    ///
2671    /// This method should only be called as part of the request_layout or prepaint phase of element drawing.
2672    pub fn request_layout(
2673        &mut self,
2674        style: Style,
2675        children: impl IntoIterator<Item = LayoutId>,
2676    ) -> LayoutId {
2677        debug_assert_eq!(
2678            self.window.draw_phase,
2679            DrawPhase::Prepaint,
2680            "this method can only be called during request_layout, or prepaint"
2681        );
2682
2683        self.app.layout_id_buffer.clear();
2684        self.app.layout_id_buffer.extend(children);
2685        let rem_size = self.rem_size();
2686
2687        self.window.layout_engine.as_mut().unwrap().request_layout(
2688            style,
2689            rem_size,
2690            &self.app.layout_id_buffer,
2691        )
2692    }
2693
2694    /// Add a node to the layout tree for the current frame. Instead of taking a `Style` and children,
2695    /// this variant takes a function that is invoked during layout so you can use arbitrary logic to
2696    /// determine the element's size. One place this is used internally is when measuring text.
2697    ///
2698    /// The given closure is invoked at layout time with the known dimensions and available space and
2699    /// returns a `Size`.
2700    ///
2701    /// This method should only be called as part of the request_layout or prepaint phase of element drawing.
2702    pub fn request_measured_layout<
2703        F: FnMut(Size<Option<Pixels>>, Size<AvailableSpace>, &mut WindowContext) -> Size<Pixels>
2704            + 'static,
2705    >(
2706        &mut self,
2707        style: Style,
2708        measure: F,
2709    ) -> LayoutId {
2710        debug_assert_eq!(
2711            self.window.draw_phase,
2712            DrawPhase::Prepaint,
2713            "this method can only be called during request_layout, or prepaint"
2714        );
2715
2716        let rem_size = self.rem_size();
2717        self.window
2718            .layout_engine
2719            .as_mut()
2720            .unwrap()
2721            .request_measured_layout(style, rem_size, measure)
2722    }
2723
2724    /// Compute the layout for the given id within the given available space.
2725    /// This method is called for its side effect, typically by the framework prior to painting.
2726    /// After calling it, you can request the bounds of the given layout node id or any descendant.
2727    ///
2728    /// This method should only be called as part of the prepaint phase of element drawing.
2729    pub fn compute_layout(&mut self, layout_id: LayoutId, available_space: Size<AvailableSpace>) {
2730        debug_assert_eq!(
2731            self.window.draw_phase,
2732            DrawPhase::Prepaint,
2733            "this method can only be called during request_layout, or prepaint"
2734        );
2735
2736        let mut layout_engine = self.window.layout_engine.take().unwrap();
2737        layout_engine.compute_layout(layout_id, available_space, self);
2738        self.window.layout_engine = Some(layout_engine);
2739    }
2740
2741    /// Obtain the bounds computed for the given LayoutId relative to the window. This method will usually be invoked by
2742    /// GPUI itself automatically in order to pass your element its `Bounds` automatically.
2743    ///
2744    /// This method should only be called as part of element drawing.
2745    pub fn layout_bounds(&mut self, layout_id: LayoutId) -> Bounds<Pixels> {
2746        debug_assert_eq!(
2747            self.window.draw_phase,
2748            DrawPhase::Prepaint,
2749            "this method can only be called during request_layout, prepaint, or paint"
2750        );
2751
2752        let mut bounds = self
2753            .window
2754            .layout_engine
2755            .as_mut()
2756            .unwrap()
2757            .layout_bounds(layout_id)
2758            .map(Into::into);
2759        bounds.origin += self.element_offset();
2760        bounds
2761    }
2762
2763    /// This method should be called during `prepaint`. You can use
2764    /// the returned [Hitbox] during `paint` or in an event handler
2765    /// to determine whether the inserted hitbox was the topmost.
2766    ///
2767    /// This method should only be called as part of the prepaint phase of element drawing.
2768    pub fn insert_hitbox(&mut self, bounds: Bounds<Pixels>, opaque: bool) -> Hitbox {
2769        debug_assert_eq!(
2770            self.window.draw_phase,
2771            DrawPhase::Prepaint,
2772            "this method can only be called during prepaint"
2773        );
2774
2775        let content_mask = self.content_mask();
2776        let window = &mut self.window;
2777        let id = window.next_hitbox_id;
2778        window.next_hitbox_id.0 += 1;
2779        let hitbox = Hitbox {
2780            id,
2781            bounds,
2782            content_mask,
2783            opaque,
2784        };
2785        window.next_frame.hitboxes.push(hitbox.clone());
2786        hitbox
2787    }
2788
2789    /// Sets the key context for the current element. This context will be used to translate
2790    /// keybindings into actions.
2791    ///
2792    /// This method should only be called as part of the paint phase of element drawing.
2793    pub fn set_key_context(&mut self, context: KeyContext) {
2794        debug_assert_eq!(
2795            self.window.draw_phase,
2796            DrawPhase::Paint,
2797            "this method can only be called during paint"
2798        );
2799        self.window
2800            .next_frame
2801            .dispatch_tree
2802            .set_key_context(context);
2803    }
2804
2805    /// Sets the focus handle for the current element. This handle will be used to manage focus state
2806    /// and keyboard event dispatch for the element.
2807    ///
2808    /// This method should only be called as part of the prepaint phase of element drawing.
2809    pub fn set_focus_handle(&mut self, focus_handle: &FocusHandle) {
2810        debug_assert_eq!(
2811            self.window.draw_phase,
2812            DrawPhase::Prepaint,
2813            "this method can only be called during prepaint"
2814        );
2815        if focus_handle.is_focused(self) {
2816            self.window.next_frame.focus = Some(focus_handle.id);
2817        }
2818        self.window
2819            .next_frame
2820            .dispatch_tree
2821            .set_focus_id(focus_handle.id);
2822    }
2823
2824    /// Sets the view id for the current element, which will be used to manage view caching.
2825    ///
2826    /// This method should only be called as part of element prepaint. We plan on removing this
2827    /// method eventually when we solve some issues that require us to construct editor elements
2828    /// directly instead of always using editors via views.
2829    pub fn set_view_id(&mut self, view_id: EntityId) {
2830        debug_assert_eq!(
2831            self.window.draw_phase,
2832            DrawPhase::Prepaint,
2833            "this method can only be called during prepaint"
2834        );
2835        self.window.next_frame.dispatch_tree.set_view_id(view_id);
2836    }
2837
2838    /// Get the last view id for the current element
2839    pub fn parent_view_id(&mut self) -> Option<EntityId> {
2840        self.window.next_frame.dispatch_tree.parent_view_id()
2841    }
2842
2843    /// Sets an input handler, such as [`ElementInputHandler`][element_input_handler], which interfaces with the
2844    /// platform to receive textual input with proper integration with concerns such
2845    /// as IME interactions. This handler will be active for the upcoming frame until the following frame is
2846    /// rendered.
2847    ///
2848    /// This method should only be called as part of the paint phase of element drawing.
2849    ///
2850    /// [element_input_handler]: crate::ElementInputHandler
2851    pub fn handle_input(&mut self, focus_handle: &FocusHandle, input_handler: impl InputHandler) {
2852        debug_assert_eq!(
2853            self.window.draw_phase,
2854            DrawPhase::Paint,
2855            "this method can only be called during paint"
2856        );
2857
2858        if focus_handle.is_focused(self) {
2859            let cx = self.to_async();
2860            self.window
2861                .next_frame
2862                .input_handlers
2863                .push(Some(PlatformInputHandler::new(cx, Box::new(input_handler))));
2864        }
2865    }
2866
2867    /// Register a mouse event listener on the window for the next frame. The type of event
2868    /// is determined by the first parameter of the given listener. When the next frame is rendered
2869    /// the listener will be cleared.
2870    ///
2871    /// This method should only be called as part of the paint phase of element drawing.
2872    pub fn on_mouse_event<Event: MouseEvent>(
2873        &mut self,
2874        mut handler: impl FnMut(&Event, DispatchPhase, &mut WindowContext) + 'static,
2875    ) {
2876        debug_assert_eq!(
2877            self.window.draw_phase,
2878            DrawPhase::Paint,
2879            "this method can only be called during paint"
2880        );
2881
2882        self.window.next_frame.mouse_listeners.push(Some(Box::new(
2883            move |event: &dyn Any, phase: DispatchPhase, cx: &mut WindowContext<'_>| {
2884                if let Some(event) = event.downcast_ref() {
2885                    handler(event, phase, cx)
2886                }
2887            },
2888        )));
2889    }
2890
2891    /// Register a key event listener on the window for the next frame. The type of event
2892    /// is determined by the first parameter of the given listener. When the next frame is rendered
2893    /// the listener will be cleared.
2894    ///
2895    /// This is a fairly low-level method, so prefer using event handlers on elements unless you have
2896    /// a specific need to register a global listener.
2897    ///
2898    /// This method should only be called as part of the paint phase of element drawing.
2899    pub fn on_key_event<Event: KeyEvent>(
2900        &mut self,
2901        listener: impl Fn(&Event, DispatchPhase, &mut WindowContext) + 'static,
2902    ) {
2903        debug_assert_eq!(
2904            self.window.draw_phase,
2905            DrawPhase::Paint,
2906            "this method can only be called during paint"
2907        );
2908
2909        self.window.next_frame.dispatch_tree.on_key_event(Rc::new(
2910            move |event: &dyn Any, phase, cx: &mut WindowContext<'_>| {
2911                if let Some(event) = event.downcast_ref::<Event>() {
2912                    listener(event, phase, cx)
2913                }
2914            },
2915        ));
2916    }
2917
2918    /// Register a modifiers changed event listener on the window for the next frame.
2919    ///
2920    /// This is a fairly low-level method, so prefer using event handlers on elements unless you have
2921    /// a specific need to register a global listener.
2922    ///
2923    /// This method should only be called as part of the paint phase of element drawing.
2924    pub fn on_modifiers_changed(
2925        &mut self,
2926        listener: impl Fn(&ModifiersChangedEvent, &mut WindowContext) + 'static,
2927    ) {
2928        debug_assert_eq!(
2929            self.window.draw_phase,
2930            DrawPhase::Paint,
2931            "this method can only be called during paint"
2932        );
2933
2934        self.window
2935            .next_frame
2936            .dispatch_tree
2937            .on_modifiers_changed(Rc::new(
2938                move |event: &ModifiersChangedEvent, cx: &mut WindowContext<'_>| {
2939                    listener(event, cx)
2940                },
2941            ));
2942    }
2943
2944    /// Register a listener to be called when the given focus handle or one of its descendants receives focus.
2945    /// This does not fire if the given focus handle - or one of its descendants - was previously focused.
2946    /// Returns a subscription and persists until the subscription is dropped.
2947    pub fn on_focus_in(
2948        &mut self,
2949        handle: &FocusHandle,
2950        mut listener: impl FnMut(&mut WindowContext) + 'static,
2951    ) -> Subscription {
2952        let focus_id = handle.id;
2953        let (subscription, activate) =
2954            self.window.new_focus_listener(Box::new(move |event, cx| {
2955                if event.is_focus_in(focus_id) {
2956                    listener(cx);
2957                }
2958                true
2959            }));
2960        self.app.defer(move |_| activate());
2961        subscription
2962    }
2963
2964    /// Register a listener to be called when the given focus handle or one of its descendants loses focus.
2965    /// Returns a subscription and persists until the subscription is dropped.
2966    pub fn on_focus_out(
2967        &mut self,
2968        handle: &FocusHandle,
2969        mut listener: impl FnMut(FocusOutEvent, &mut WindowContext) + 'static,
2970    ) -> Subscription {
2971        let focus_id = handle.id;
2972        let (subscription, activate) =
2973            self.window.new_focus_listener(Box::new(move |event, cx| {
2974                if let Some(blurred_id) = event.previous_focus_path.last().copied() {
2975                    if event.is_focus_out(focus_id) {
2976                        let event = FocusOutEvent {
2977                            blurred: WeakFocusHandle {
2978                                id: blurred_id,
2979                                handles: Arc::downgrade(&cx.window.focus_handles),
2980                            },
2981                        };
2982                        listener(event, cx)
2983                    }
2984                }
2985                true
2986            }));
2987        self.app.defer(move |_| activate());
2988        subscription
2989    }
2990
2991    fn reset_cursor_style(&self) {
2992        // Set the cursor only if we're the active window.
2993        if self.is_window_hovered() {
2994            let style = self
2995                .window
2996                .rendered_frame
2997                .cursor_styles
2998                .iter()
2999                .rev()
3000                .find(|request| request.hitbox_id.is_hovered(self))
3001                .map(|request| request.style)
3002                .unwrap_or(CursorStyle::Arrow);
3003            self.platform.set_cursor_style(style);
3004        }
3005    }
3006
3007    /// Dispatch a given keystroke as though the user had typed it.
3008    /// You can create a keystroke with Keystroke::parse("").
3009    pub fn dispatch_keystroke(&mut self, keystroke: Keystroke) -> bool {
3010        let keystroke = keystroke.with_simulated_ime();
3011        let result = self.dispatch_event(PlatformInput::KeyDown(KeyDownEvent {
3012            keystroke: keystroke.clone(),
3013            is_held: false,
3014        }));
3015        if !result.propagate {
3016            return true;
3017        }
3018
3019        if let Some(input) = keystroke.ime_key {
3020            if let Some(mut input_handler) = self.window.platform_window.take_input_handler() {
3021                input_handler.dispatch_input(&input, self);
3022                self.window.platform_window.set_input_handler(input_handler);
3023                return true;
3024            }
3025        }
3026
3027        false
3028    }
3029
3030    /// Represent this action as a key binding string, to display in the UI.
3031    pub fn keystroke_text_for(&self, action: &dyn Action) -> String {
3032        self.bindings_for_action(action)
3033            .into_iter()
3034            .next()
3035            .map(|binding| {
3036                binding
3037                    .keystrokes()
3038                    .iter()
3039                    .map(ToString::to_string)
3040                    .collect::<Vec<_>>()
3041                    .join(" ")
3042            })
3043            .unwrap_or_else(|| action.name().to_string())
3044    }
3045
3046    /// Dispatch a mouse or keyboard event on the window.
3047    #[profiling::function]
3048    pub fn dispatch_event(&mut self, event: PlatformInput) -> DispatchEventResult {
3049        self.window.last_input_timestamp.set(Instant::now());
3050        // Handlers may set this to false by calling `stop_propagation`.
3051        self.app.propagate_event = true;
3052        // Handlers may set this to true by calling `prevent_default`.
3053        self.window.default_prevented = false;
3054
3055        let event = match event {
3056            // Track the mouse position with our own state, since accessing the platform
3057            // API for the mouse position can only occur on the main thread.
3058            PlatformInput::MouseMove(mouse_move) => {
3059                self.window.mouse_position = mouse_move.position;
3060                self.window.modifiers = mouse_move.modifiers;
3061                PlatformInput::MouseMove(mouse_move)
3062            }
3063            PlatformInput::MouseDown(mouse_down) => {
3064                self.window.mouse_position = mouse_down.position;
3065                self.window.modifiers = mouse_down.modifiers;
3066                PlatformInput::MouseDown(mouse_down)
3067            }
3068            PlatformInput::MouseUp(mouse_up) => {
3069                self.window.mouse_position = mouse_up.position;
3070                self.window.modifiers = mouse_up.modifiers;
3071                PlatformInput::MouseUp(mouse_up)
3072            }
3073            PlatformInput::MouseExited(mouse_exited) => {
3074                self.window.modifiers = mouse_exited.modifiers;
3075                PlatformInput::MouseExited(mouse_exited)
3076            }
3077            PlatformInput::ModifiersChanged(modifiers_changed) => {
3078                self.window.modifiers = modifiers_changed.modifiers;
3079                PlatformInput::ModifiersChanged(modifiers_changed)
3080            }
3081            PlatformInput::ScrollWheel(scroll_wheel) => {
3082                self.window.mouse_position = scroll_wheel.position;
3083                self.window.modifiers = scroll_wheel.modifiers;
3084                PlatformInput::ScrollWheel(scroll_wheel)
3085            }
3086            // Translate dragging and dropping of external files from the operating system
3087            // to internal drag and drop events.
3088            PlatformInput::FileDrop(file_drop) => match file_drop {
3089                FileDropEvent::Entered { position, paths } => {
3090                    self.window.mouse_position = position;
3091                    if self.active_drag.is_none() {
3092                        self.active_drag = Some(AnyDrag {
3093                            value: Box::new(paths.clone()),
3094                            view: self.new_view(|_| paths).into(),
3095                            cursor_offset: position,
3096                        });
3097                    }
3098                    PlatformInput::MouseMove(MouseMoveEvent {
3099                        position,
3100                        pressed_button: Some(MouseButton::Left),
3101                        modifiers: Modifiers::default(),
3102                    })
3103                }
3104                FileDropEvent::Pending { position } => {
3105                    self.window.mouse_position = position;
3106                    PlatformInput::MouseMove(MouseMoveEvent {
3107                        position,
3108                        pressed_button: Some(MouseButton::Left),
3109                        modifiers: Modifiers::default(),
3110                    })
3111                }
3112                FileDropEvent::Submit { position } => {
3113                    self.activate(true);
3114                    self.window.mouse_position = position;
3115                    PlatformInput::MouseUp(MouseUpEvent {
3116                        button: MouseButton::Left,
3117                        position,
3118                        modifiers: Modifiers::default(),
3119                        click_count: 1,
3120                    })
3121                }
3122                FileDropEvent::Exited => {
3123                    self.active_drag.take();
3124                    PlatformInput::FileDrop(FileDropEvent::Exited)
3125                }
3126            },
3127            PlatformInput::KeyDown(_) | PlatformInput::KeyUp(_) => event,
3128        };
3129
3130        if let Some(any_mouse_event) = event.mouse_event() {
3131            self.dispatch_mouse_event(any_mouse_event);
3132        } else if let Some(any_key_event) = event.keyboard_event() {
3133            self.dispatch_key_event(any_key_event);
3134        }
3135
3136        DispatchEventResult {
3137            propagate: self.app.propagate_event,
3138            default_prevented: self.window.default_prevented,
3139        }
3140    }
3141
3142    fn dispatch_mouse_event(&mut self, event: &dyn Any) {
3143        let hit_test = self.window.rendered_frame.hit_test(self.mouse_position());
3144        if hit_test != self.window.mouse_hit_test {
3145            self.window.mouse_hit_test = hit_test;
3146            self.reset_cursor_style();
3147        }
3148
3149        let mut mouse_listeners = mem::take(&mut self.window.rendered_frame.mouse_listeners);
3150
3151        // Capture phase, events bubble from back to front. Handlers for this phase are used for
3152        // special purposes, such as detecting events outside of a given Bounds.
3153        for listener in &mut mouse_listeners {
3154            let listener = listener.as_mut().unwrap();
3155            listener(event, DispatchPhase::Capture, self);
3156            if !self.app.propagate_event {
3157                break;
3158            }
3159        }
3160
3161        // Bubble phase, where most normal handlers do their work.
3162        if self.app.propagate_event {
3163            for listener in mouse_listeners.iter_mut().rev() {
3164                let listener = listener.as_mut().unwrap();
3165                listener(event, DispatchPhase::Bubble, self);
3166                if !self.app.propagate_event {
3167                    break;
3168                }
3169            }
3170        }
3171
3172        self.window.rendered_frame.mouse_listeners = mouse_listeners;
3173
3174        if self.has_active_drag() {
3175            if event.is::<MouseMoveEvent>() {
3176                // If this was a mouse move event, redraw the window so that the
3177                // active drag can follow the mouse cursor.
3178                self.refresh();
3179            } else if event.is::<MouseUpEvent>() {
3180                // If this was a mouse up event, cancel the active drag and redraw
3181                // the window.
3182                self.active_drag = None;
3183                self.refresh();
3184            }
3185        }
3186    }
3187
3188    fn dispatch_key_event(&mut self, event: &dyn Any) {
3189        if self.window.dirty.get() {
3190            self.draw();
3191        }
3192
3193        let node_id = self
3194            .window
3195            .focus
3196            .and_then(|focus_id| {
3197                self.window
3198                    .rendered_frame
3199                    .dispatch_tree
3200                    .focusable_node_id(focus_id)
3201            })
3202            .unwrap_or_else(|| self.window.rendered_frame.dispatch_tree.root_node_id());
3203
3204        let dispatch_path = self
3205            .window
3206            .rendered_frame
3207            .dispatch_tree
3208            .dispatch_path(node_id);
3209
3210        let mut keystroke: Option<Keystroke> = None;
3211
3212        if let Some(event) = event.downcast_ref::<ModifiersChangedEvent>() {
3213            if event.modifiers.number_of_modifiers() == 0
3214                && self.window.pending_modifier.modifiers.number_of_modifiers() == 1
3215                && !self.window.pending_modifier.saw_keystroke
3216            {
3217                if event.modifiers.number_of_modifiers() == 0 {
3218                    let key = match self.window.pending_modifier.modifiers {
3219                        modifiers if modifiers.shift => Some("shift"),
3220                        modifiers if modifiers.control => Some("control"),
3221                        modifiers if modifiers.alt => Some("alt"),
3222                        modifiers if modifiers.platform => Some("platform"),
3223                        modifiers if modifiers.function => Some("function"),
3224                        _ => None,
3225                    };
3226                    if let Some(key) = key {
3227                        keystroke = Some(Keystroke {
3228                            key: key.to_string(),
3229                            ime_key: None,
3230                            modifiers: Modifiers::default(),
3231                        });
3232                    }
3233                }
3234            }
3235            if self.window.pending_modifier.modifiers.number_of_modifiers() == 0
3236                && event.modifiers.number_of_modifiers() == 1
3237            {
3238                self.window.pending_modifier.saw_keystroke = false
3239            }
3240            self.window.pending_modifier.modifiers = event.modifiers
3241        } else if let Some(key_down_event) = event.downcast_ref::<KeyDownEvent>() {
3242            self.window.pending_modifier.saw_keystroke = true;
3243            keystroke = Some(key_down_event.keystroke.clone());
3244        }
3245
3246        let Some(keystroke) = keystroke else {
3247            self.finish_dispatch_key_event(event, dispatch_path);
3248            return;
3249        };
3250
3251        let mut currently_pending = self.window.pending_input.take().unwrap_or_default();
3252        if currently_pending.focus.is_some() && currently_pending.focus != self.window.focus {
3253            currently_pending = PendingInput::default();
3254        }
3255
3256        let match_result = self.window.rendered_frame.dispatch_tree.dispatch_key(
3257            currently_pending.keystrokes,
3258            keystroke,
3259            &dispatch_path,
3260        );
3261        if !match_result.to_replay.is_empty() {
3262            self.replay_pending_input(match_result.to_replay)
3263        }
3264
3265        if !match_result.pending.is_empty() {
3266            currently_pending.keystrokes = match_result.pending;
3267            currently_pending.focus = self.window.focus;
3268            currently_pending.timer = Some(self.spawn(|mut cx| async move {
3269                cx.background_executor.timer(Duration::from_secs(1)).await;
3270                cx.update(move |cx| {
3271                    let Some(currently_pending) = cx
3272                        .window
3273                        .pending_input
3274                        .take()
3275                        .filter(|pending| pending.focus == cx.window.focus)
3276                    else {
3277                        return;
3278                    };
3279
3280                    let dispatch_path = cx
3281                        .window
3282                        .rendered_frame
3283                        .dispatch_tree
3284                        .dispatch_path(node_id);
3285
3286                    let to_replay = cx
3287                        .window
3288                        .rendered_frame
3289                        .dispatch_tree
3290                        .flush_dispatch(currently_pending.keystrokes, &dispatch_path);
3291
3292                    cx.replay_pending_input(to_replay)
3293                })
3294                .log_err();
3295            }));
3296            self.window.pending_input = Some(currently_pending);
3297            self.pending_input_changed();
3298            self.propagate_event = false;
3299            return;
3300        }
3301
3302        self.pending_input_changed();
3303        self.propagate_event = true;
3304        for binding in match_result.bindings {
3305            self.dispatch_action_on_node(node_id, binding.action.as_ref());
3306            if !self.propagate_event {
3307                self.dispatch_keystroke_observers(event, Some(binding.action));
3308                return;
3309            }
3310        }
3311
3312        self.finish_dispatch_key_event(event, dispatch_path)
3313    }
3314
3315    fn finish_dispatch_key_event(
3316        &mut self,
3317        event: &dyn Any,
3318        dispatch_path: SmallVec<[DispatchNodeId; 32]>,
3319    ) {
3320        self.dispatch_key_down_up_event(event, &dispatch_path);
3321        if !self.propagate_event {
3322            return;
3323        }
3324
3325        self.dispatch_modifiers_changed_event(event, &dispatch_path);
3326        if !self.propagate_event {
3327            return;
3328        }
3329
3330        self.dispatch_keystroke_observers(event, None);
3331    }
3332
3333    fn pending_input_changed(&mut self) {
3334        self.window
3335            .pending_input_observers
3336            .clone()
3337            .retain(&(), |callback| callback(self));
3338    }
3339
3340    fn dispatch_key_down_up_event(
3341        &mut self,
3342        event: &dyn Any,
3343        dispatch_path: &SmallVec<[DispatchNodeId; 32]>,
3344    ) {
3345        // Capture phase
3346        for node_id in dispatch_path {
3347            let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
3348
3349            for key_listener in node.key_listeners.clone() {
3350                key_listener(event, DispatchPhase::Capture, self);
3351                if !self.propagate_event {
3352                    return;
3353                }
3354            }
3355        }
3356
3357        // Bubble phase
3358        for node_id in dispatch_path.iter().rev() {
3359            // Handle low level key events
3360            let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
3361            for key_listener in node.key_listeners.clone() {
3362                key_listener(event, DispatchPhase::Bubble, self);
3363                if !self.propagate_event {
3364                    return;
3365                }
3366            }
3367        }
3368    }
3369
3370    fn dispatch_modifiers_changed_event(
3371        &mut self,
3372        event: &dyn Any,
3373        dispatch_path: &SmallVec<[DispatchNodeId; 32]>,
3374    ) {
3375        let Some(event) = event.downcast_ref::<ModifiersChangedEvent>() else {
3376            return;
3377        };
3378        for node_id in dispatch_path.iter().rev() {
3379            let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
3380            for listener in node.modifiers_changed_listeners.clone() {
3381                listener(event, self);
3382                if !self.propagate_event {
3383                    return;
3384                }
3385            }
3386        }
3387    }
3388
3389    /// Determine whether a potential multi-stroke key binding is in progress on this window.
3390    pub fn has_pending_keystrokes(&self) -> bool {
3391        self.window.pending_input.is_some()
3392    }
3393
3394    fn clear_pending_keystrokes(&mut self) {
3395        self.window.pending_input.take();
3396    }
3397
3398    /// Returns the currently pending input keystrokes that might result in a multi-stroke key binding.
3399    pub fn pending_input_keystrokes(&self) -> Option<&[Keystroke]> {
3400        self.window
3401            .pending_input
3402            .as_ref()
3403            .map(|pending_input| pending_input.keystrokes.as_slice())
3404    }
3405
3406    fn replay_pending_input(&mut self, replays: SmallVec<[Replay; 1]>) {
3407        let node_id = self
3408            .window
3409            .focus
3410            .and_then(|focus_id| {
3411                self.window
3412                    .rendered_frame
3413                    .dispatch_tree
3414                    .focusable_node_id(focus_id)
3415            })
3416            .unwrap_or_else(|| self.window.rendered_frame.dispatch_tree.root_node_id());
3417
3418        let dispatch_path = self
3419            .window
3420            .rendered_frame
3421            .dispatch_tree
3422            .dispatch_path(node_id);
3423
3424        'replay: for replay in replays {
3425            let event = KeyDownEvent {
3426                keystroke: replay.keystroke.clone(),
3427                is_held: false,
3428            };
3429
3430            self.propagate_event = true;
3431            for binding in replay.bindings {
3432                self.dispatch_action_on_node(node_id, binding.action.as_ref());
3433                if !self.propagate_event {
3434                    self.dispatch_keystroke_observers(&event, Some(binding.action));
3435                    continue 'replay;
3436                }
3437            }
3438
3439            self.dispatch_key_down_up_event(&event, &dispatch_path);
3440            if !self.propagate_event {
3441                continue 'replay;
3442            }
3443            if let Some(input) = replay.keystroke.ime_key.as_ref().cloned() {
3444                if let Some(mut input_handler) = self.window.platform_window.take_input_handler() {
3445                    input_handler.dispatch_input(&input, self);
3446                    self.window.platform_window.set_input_handler(input_handler)
3447                }
3448            }
3449        }
3450    }
3451
3452    fn dispatch_action_on_node(&mut self, node_id: DispatchNodeId, action: &dyn Action) {
3453        let dispatch_path = self
3454            .window
3455            .rendered_frame
3456            .dispatch_tree
3457            .dispatch_path(node_id);
3458
3459        // Capture phase for global actions.
3460        self.propagate_event = true;
3461        if let Some(mut global_listeners) = self
3462            .global_action_listeners
3463            .remove(&action.as_any().type_id())
3464        {
3465            for listener in &global_listeners {
3466                listener(action.as_any(), DispatchPhase::Capture, self);
3467                if !self.propagate_event {
3468                    break;
3469                }
3470            }
3471
3472            global_listeners.extend(
3473                self.global_action_listeners
3474                    .remove(&action.as_any().type_id())
3475                    .unwrap_or_default(),
3476            );
3477
3478            self.global_action_listeners
3479                .insert(action.as_any().type_id(), global_listeners);
3480        }
3481
3482        if !self.propagate_event {
3483            return;
3484        }
3485
3486        // Capture phase for window actions.
3487        for node_id in &dispatch_path {
3488            let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
3489            for DispatchActionListener {
3490                action_type,
3491                listener,
3492            } in node.action_listeners.clone()
3493            {
3494                let any_action = action.as_any();
3495                if action_type == any_action.type_id() {
3496                    listener(any_action, DispatchPhase::Capture, self);
3497
3498                    if !self.propagate_event {
3499                        return;
3500                    }
3501                }
3502            }
3503        }
3504
3505        // Bubble phase for window actions.
3506        for node_id in dispatch_path.iter().rev() {
3507            let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
3508            for DispatchActionListener {
3509                action_type,
3510                listener,
3511            } in node.action_listeners.clone()
3512            {
3513                let any_action = action.as_any();
3514                if action_type == any_action.type_id() {
3515                    self.propagate_event = false; // Actions stop propagation by default during the bubble phase
3516                    listener(any_action, DispatchPhase::Bubble, self);
3517
3518                    if !self.propagate_event {
3519                        return;
3520                    }
3521                }
3522            }
3523        }
3524
3525        // Bubble phase for global actions.
3526        if let Some(mut global_listeners) = self
3527            .global_action_listeners
3528            .remove(&action.as_any().type_id())
3529        {
3530            for listener in global_listeners.iter().rev() {
3531                self.propagate_event = false; // Actions stop propagation by default during the bubble phase
3532
3533                listener(action.as_any(), DispatchPhase::Bubble, self);
3534                if !self.propagate_event {
3535                    break;
3536                }
3537            }
3538
3539            global_listeners.extend(
3540                self.global_action_listeners
3541                    .remove(&action.as_any().type_id())
3542                    .unwrap_or_default(),
3543            );
3544
3545            self.global_action_listeners
3546                .insert(action.as_any().type_id(), global_listeners);
3547        }
3548    }
3549
3550    /// Register the given handler to be invoked whenever the global of the given type
3551    /// is updated.
3552    pub fn observe_global<G: Global>(
3553        &mut self,
3554        f: impl Fn(&mut WindowContext<'_>) + 'static,
3555    ) -> Subscription {
3556        let window_handle = self.window.handle;
3557        let (subscription, activate) = self.global_observers.insert(
3558            TypeId::of::<G>(),
3559            Box::new(move |cx| window_handle.update(cx, |_, cx| f(cx)).is_ok()),
3560        );
3561        self.app.defer(move |_| activate());
3562        subscription
3563    }
3564
3565    /// Focus the current window and bring it to the foreground at the platform level.
3566    pub fn activate_window(&self) {
3567        self.window.platform_window.activate();
3568    }
3569
3570    /// Minimize the current window at the platform level.
3571    pub fn minimize_window(&self) {
3572        self.window.platform_window.minimize();
3573    }
3574
3575    /// Toggle full screen status on the current window at the platform level.
3576    pub fn toggle_fullscreen(&self) {
3577        self.window.platform_window.toggle_fullscreen();
3578    }
3579
3580    /// Present a platform dialog.
3581    /// The provided message will be presented, along with buttons for each answer.
3582    /// When a button is clicked, the returned Receiver will receive the index of the clicked button.
3583    pub fn prompt(
3584        &mut self,
3585        level: PromptLevel,
3586        message: &str,
3587        detail: Option<&str>,
3588        answers: &[&str],
3589    ) -> oneshot::Receiver<usize> {
3590        let prompt_builder = self.app.prompt_builder.take();
3591        let Some(prompt_builder) = prompt_builder else {
3592            unreachable!("Re-entrant window prompting is not supported by GPUI");
3593        };
3594
3595        let receiver = match &prompt_builder {
3596            PromptBuilder::Default => self
3597                .window
3598                .platform_window
3599                .prompt(level, message, detail, answers)
3600                .unwrap_or_else(|| {
3601                    self.build_custom_prompt(&prompt_builder, level, message, detail, answers)
3602                }),
3603            PromptBuilder::Custom(_) => {
3604                self.build_custom_prompt(&prompt_builder, level, message, detail, answers)
3605            }
3606        };
3607
3608        self.app.prompt_builder = Some(prompt_builder);
3609
3610        receiver
3611    }
3612
3613    fn build_custom_prompt(
3614        &mut self,
3615        prompt_builder: &PromptBuilder,
3616        level: PromptLevel,
3617        message: &str,
3618        detail: Option<&str>,
3619        answers: &[&str],
3620    ) -> oneshot::Receiver<usize> {
3621        let (sender, receiver) = oneshot::channel();
3622        let handle = PromptHandle::new(sender);
3623        let handle = (prompt_builder)(level, message, detail, answers, handle, self);
3624        self.window.prompt = Some(handle);
3625        receiver
3626    }
3627
3628    /// Returns all available actions for the focused element.
3629    pub fn available_actions(&self) -> Vec<Box<dyn Action>> {
3630        let node_id = self
3631            .window
3632            .focus
3633            .and_then(|focus_id| {
3634                self.window
3635                    .rendered_frame
3636                    .dispatch_tree
3637                    .focusable_node_id(focus_id)
3638            })
3639            .unwrap_or_else(|| self.window.rendered_frame.dispatch_tree.root_node_id());
3640
3641        let mut actions = self
3642            .window
3643            .rendered_frame
3644            .dispatch_tree
3645            .available_actions(node_id);
3646        for action_type in self.global_action_listeners.keys() {
3647            if let Err(ix) = actions.binary_search_by_key(action_type, |a| a.as_any().type_id()) {
3648                let action = self.actions.build_action_type(action_type).ok();
3649                if let Some(action) = action {
3650                    actions.insert(ix, action);
3651                }
3652            }
3653        }
3654        actions
3655    }
3656
3657    /// Returns key bindings that invoke the given action on the currently focused element.
3658    pub fn bindings_for_action(&self, action: &dyn Action) -> Vec<KeyBinding> {
3659        self.window
3660            .rendered_frame
3661            .dispatch_tree
3662            .bindings_for_action(
3663                action,
3664                &self.window.rendered_frame.dispatch_tree.context_stack,
3665            )
3666    }
3667
3668    /// Returns any bindings that would invoke the given action on the given focus handle if it were focused.
3669    pub fn bindings_for_action_in(
3670        &self,
3671        action: &dyn Action,
3672        focus_handle: &FocusHandle,
3673    ) -> Vec<KeyBinding> {
3674        let dispatch_tree = &self.window.rendered_frame.dispatch_tree;
3675
3676        let Some(node_id) = dispatch_tree.focusable_node_id(focus_handle.id) else {
3677            return vec![];
3678        };
3679        let context_stack: Vec<_> = dispatch_tree
3680            .dispatch_path(node_id)
3681            .into_iter()
3682            .filter_map(|node_id| dispatch_tree.node(node_id).context.clone())
3683            .collect();
3684        dispatch_tree.bindings_for_action(action, &context_stack)
3685    }
3686
3687    /// Returns a generic event listener that invokes the given listener with the view and context associated with the given view handle.
3688    pub fn listener_for<V: Render, E>(
3689        &self,
3690        view: &View<V>,
3691        f: impl Fn(&mut V, &E, &mut ViewContext<V>) + 'static,
3692    ) -> impl Fn(&E, &mut WindowContext) + 'static {
3693        let view = view.downgrade();
3694        move |e: &E, cx: &mut WindowContext| {
3695            view.update(cx, |view, cx| f(view, e, cx)).ok();
3696        }
3697    }
3698
3699    /// Returns a generic handler that invokes the given handler with the view and context associated with the given view handle.
3700    pub fn handler_for<V: Render>(
3701        &self,
3702        view: &View<V>,
3703        f: impl Fn(&mut V, &mut ViewContext<V>) + 'static,
3704    ) -> impl Fn(&mut WindowContext) {
3705        let view = view.downgrade();
3706        move |cx: &mut WindowContext| {
3707            view.update(cx, |view, cx| f(view, cx)).ok();
3708        }
3709    }
3710
3711    /// Register a callback that can interrupt the closing of the current window based the returned boolean.
3712    /// If the callback returns false, the window won't be closed.
3713    pub fn on_window_should_close(&mut self, f: impl Fn(&mut WindowContext) -> bool + 'static) {
3714        let mut this = self.to_async();
3715        self.window
3716            .platform_window
3717            .on_should_close(Box::new(move || this.update(|cx| f(cx)).unwrap_or(true)))
3718    }
3719
3720    /// Register an action listener on the window for the next frame. The type of action
3721    /// is determined by the first parameter of the given listener. When the next frame is rendered
3722    /// the listener will be cleared.
3723    ///
3724    /// This is a fairly low-level method, so prefer using action handlers on elements unless you have
3725    /// a specific need to register a global listener.
3726    pub fn on_action(
3727        &mut self,
3728        action_type: TypeId,
3729        listener: impl Fn(&dyn Any, DispatchPhase, &mut WindowContext) + 'static,
3730    ) {
3731        self.window
3732            .next_frame
3733            .dispatch_tree
3734            .on_action(action_type, Rc::new(listener));
3735    }
3736
3737    /// Read information about the GPU backing this window.
3738    /// Currently returns None on Mac and Windows.
3739    pub fn gpu_specs(&self) -> Option<GPUSpecs> {
3740        self.window.platform_window.gpu_specs()
3741    }
3742}
3743
3744#[cfg(target_os = "windows")]
3745impl WindowContext<'_> {
3746    /// Returns the raw HWND handle for the window.
3747    pub fn get_raw_handle(&self) -> windows::Win32::Foundation::HWND {
3748        self.window.platform_window.get_raw_handle()
3749    }
3750}
3751
3752impl Context for WindowContext<'_> {
3753    type Result<T> = T;
3754
3755    fn new_model<T>(&mut self, build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T) -> Model<T>
3756    where
3757        T: 'static,
3758    {
3759        let slot = self.app.entities.reserve();
3760        let model = build_model(&mut ModelContext::new(&mut *self.app, slot.downgrade()));
3761        self.entities.insert(slot, model)
3762    }
3763
3764    fn reserve_model<T: 'static>(&mut self) -> Self::Result<crate::Reservation<T>> {
3765        self.app.reserve_model()
3766    }
3767
3768    fn insert_model<T: 'static>(
3769        &mut self,
3770        reservation: crate::Reservation<T>,
3771        build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
3772    ) -> Self::Result<Model<T>> {
3773        self.app.insert_model(reservation, build_model)
3774    }
3775
3776    fn update_model<T: 'static, R>(
3777        &mut self,
3778        model: &Model<T>,
3779        update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
3780    ) -> R {
3781        let mut entity = self.entities.lease(model);
3782        let result = update(
3783            &mut *entity,
3784            &mut ModelContext::new(&mut *self.app, model.downgrade()),
3785        );
3786        self.entities.end_lease(entity);
3787        result
3788    }
3789
3790    fn read_model<T, R>(
3791        &self,
3792        handle: &Model<T>,
3793        read: impl FnOnce(&T, &AppContext) -> R,
3794    ) -> Self::Result<R>
3795    where
3796        T: 'static,
3797    {
3798        let entity = self.entities.read(handle);
3799        read(entity, &*self.app)
3800    }
3801
3802    fn update_window<T, F>(&mut self, window: AnyWindowHandle, update: F) -> Result<T>
3803    where
3804        F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
3805    {
3806        if window == self.window.handle {
3807            let root_view = self.window.root_view.clone().unwrap();
3808            Ok(update(root_view, self))
3809        } else {
3810            window.update(self.app, update)
3811        }
3812    }
3813
3814    fn read_window<T, R>(
3815        &self,
3816        window: &WindowHandle<T>,
3817        read: impl FnOnce(View<T>, &AppContext) -> R,
3818    ) -> Result<R>
3819    where
3820        T: 'static,
3821    {
3822        if window.any_handle == self.window.handle {
3823            let root_view = self
3824                .window
3825                .root_view
3826                .clone()
3827                .unwrap()
3828                .downcast::<T>()
3829                .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
3830            Ok(read(root_view, self))
3831        } else {
3832            self.app.read_window(window, read)
3833        }
3834    }
3835}
3836
3837impl VisualContext for WindowContext<'_> {
3838    fn new_view<V>(
3839        &mut self,
3840        build_view_state: impl FnOnce(&mut ViewContext<'_, V>) -> V,
3841    ) -> Self::Result<View<V>>
3842    where
3843        V: 'static + Render,
3844    {
3845        let slot = self.app.entities.reserve();
3846        let view = View {
3847            model: slot.clone(),
3848        };
3849        let mut cx = ViewContext::new(&mut *self.app, &mut *self.window, &view);
3850        let entity = build_view_state(&mut cx);
3851        cx.entities.insert(slot, entity);
3852
3853        // Non-generic part to avoid leaking SubscriberSet to invokers of `new_view`.
3854        fn notify_observers(cx: &mut WindowContext, tid: TypeId, view: AnyView) {
3855            cx.new_view_observers.clone().retain(&tid, |observer| {
3856                let any_view = view.clone();
3857                (observer)(any_view, cx);
3858                true
3859            });
3860        }
3861        notify_observers(self, TypeId::of::<V>(), AnyView::from(view.clone()));
3862
3863        view
3864    }
3865
3866    /// Updates the given view. Prefer calling [`View::update`] instead, which calls this method.
3867    fn update_view<T: 'static, R>(
3868        &mut self,
3869        view: &View<T>,
3870        update: impl FnOnce(&mut T, &mut ViewContext<'_, T>) -> R,
3871    ) -> Self::Result<R> {
3872        let mut lease = self.app.entities.lease(&view.model);
3873        let mut cx = ViewContext::new(&mut *self.app, &mut *self.window, view);
3874        let result = update(&mut *lease, &mut cx);
3875        cx.app.entities.end_lease(lease);
3876        result
3877    }
3878
3879    fn replace_root_view<V>(
3880        &mut self,
3881        build_view: impl FnOnce(&mut ViewContext<'_, V>) -> V,
3882    ) -> Self::Result<View<V>>
3883    where
3884        V: 'static + Render,
3885    {
3886        let view = self.new_view(build_view);
3887        self.window.root_view = Some(view.clone().into());
3888        self.refresh();
3889        view
3890    }
3891
3892    fn focus_view<V: crate::FocusableView>(&mut self, view: &View<V>) -> Self::Result<()> {
3893        self.update_view(view, |view, cx| {
3894            view.focus_handle(cx).clone().focus(cx);
3895        })
3896    }
3897
3898    fn dismiss_view<V>(&mut self, view: &View<V>) -> Self::Result<()>
3899    where
3900        V: ManagedView,
3901    {
3902        self.update_view(view, |_, cx| cx.emit(DismissEvent))
3903    }
3904}
3905
3906impl<'a> std::ops::Deref for WindowContext<'a> {
3907    type Target = AppContext;
3908
3909    fn deref(&self) -> &Self::Target {
3910        self.app
3911    }
3912}
3913
3914impl<'a> std::ops::DerefMut for WindowContext<'a> {
3915    fn deref_mut(&mut self) -> &mut Self::Target {
3916        self.app
3917    }
3918}
3919
3920impl<'a> Borrow<AppContext> for WindowContext<'a> {
3921    fn borrow(&self) -> &AppContext {
3922        self.app
3923    }
3924}
3925
3926impl<'a> BorrowMut<AppContext> for WindowContext<'a> {
3927    fn borrow_mut(&mut self) -> &mut AppContext {
3928        self.app
3929    }
3930}
3931
3932/// This trait contains functionality that is shared across [`ViewContext`] and [`WindowContext`]
3933pub trait BorrowWindow: BorrowMut<Window> + BorrowMut<AppContext> {
3934    #[doc(hidden)]
3935    fn app_mut(&mut self) -> &mut AppContext {
3936        self.borrow_mut()
3937    }
3938
3939    #[doc(hidden)]
3940    fn app(&self) -> &AppContext {
3941        self.borrow()
3942    }
3943
3944    #[doc(hidden)]
3945    fn window(&self) -> &Window {
3946        self.borrow()
3947    }
3948
3949    #[doc(hidden)]
3950    fn window_mut(&mut self) -> &mut Window {
3951        self.borrow_mut()
3952    }
3953}
3954
3955impl Borrow<Window> for WindowContext<'_> {
3956    fn borrow(&self) -> &Window {
3957        self.window
3958    }
3959}
3960
3961impl BorrowMut<Window> for WindowContext<'_> {
3962    fn borrow_mut(&mut self) -> &mut Window {
3963        self.window
3964    }
3965}
3966
3967impl<T> BorrowWindow for T where T: BorrowMut<AppContext> + BorrowMut<Window> {}
3968
3969/// Provides access to application state that is specialized for a particular [`View`].
3970/// Allows you to interact with focus, emit events, etc.
3971/// ViewContext also derefs to [`WindowContext`], giving you access to all of its methods as well.
3972/// When you call [`View::update`], you're passed a `&mut V` and an `&mut ViewContext<V>`.
3973pub struct ViewContext<'a, V> {
3974    window_cx: WindowContext<'a>,
3975    view: &'a View<V>,
3976}
3977
3978impl<V> Borrow<AppContext> for ViewContext<'_, V> {
3979    fn borrow(&self) -> &AppContext {
3980        &*self.window_cx.app
3981    }
3982}
3983
3984impl<V> BorrowMut<AppContext> for ViewContext<'_, V> {
3985    fn borrow_mut(&mut self) -> &mut AppContext {
3986        &mut *self.window_cx.app
3987    }
3988}
3989
3990impl<V> Borrow<Window> for ViewContext<'_, V> {
3991    fn borrow(&self) -> &Window {
3992        &*self.window_cx.window
3993    }
3994}
3995
3996impl<V> BorrowMut<Window> for ViewContext<'_, V> {
3997    fn borrow_mut(&mut self) -> &mut Window {
3998        &mut *self.window_cx.window
3999    }
4000}
4001
4002impl<'a, V: 'static> ViewContext<'a, V> {
4003    pub(crate) fn new(app: &'a mut AppContext, window: &'a mut Window, view: &'a View<V>) -> Self {
4004        Self {
4005            window_cx: WindowContext::new(app, window),
4006            view,
4007        }
4008    }
4009
4010    /// Get the entity_id of this view.
4011    pub fn entity_id(&self) -> EntityId {
4012        self.view.entity_id()
4013    }
4014
4015    /// Get the view pointer underlying this context.
4016    pub fn view(&self) -> &View<V> {
4017        self.view
4018    }
4019
4020    /// Get the model underlying this view.
4021    pub fn model(&self) -> &Model<V> {
4022        &self.view.model
4023    }
4024
4025    /// Access the underlying window context.
4026    pub fn window_context(&mut self) -> &mut WindowContext<'a> {
4027        &mut self.window_cx
4028    }
4029
4030    /// Sets a given callback to be run on the next frame.
4031    pub fn on_next_frame(&mut self, f: impl FnOnce(&mut V, &mut ViewContext<V>) + 'static)
4032    where
4033        V: 'static,
4034    {
4035        let view = self.view().clone();
4036        self.window_cx.on_next_frame(move |cx| view.update(cx, f));
4037    }
4038
4039    /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
4040    /// that are currently on the stack to be returned to the app.
4041    pub fn defer(&mut self, f: impl FnOnce(&mut V, &mut ViewContext<V>) + 'static) {
4042        let view = self.view().downgrade();
4043        self.window_cx.defer(move |cx| {
4044            view.update(cx, f).ok();
4045        });
4046    }
4047
4048    /// Observe another model or view for changes to its state, as tracked by [`ModelContext::notify`].
4049    pub fn observe<V2, E>(
4050        &mut self,
4051        entity: &E,
4052        mut on_notify: impl FnMut(&mut V, E, &mut ViewContext<'_, V>) + 'static,
4053    ) -> Subscription
4054    where
4055        V2: 'static,
4056        V: 'static,
4057        E: Entity<V2>,
4058    {
4059        let view = self.view().downgrade();
4060        let entity_id = entity.entity_id();
4061        let entity = entity.downgrade();
4062        let window_handle = self.window.handle;
4063        self.app.new_observer(
4064            entity_id,
4065            Box::new(move |cx| {
4066                window_handle
4067                    .update(cx, |_, cx| {
4068                        if let Some(handle) = E::upgrade_from(&entity) {
4069                            view.update(cx, |this, cx| on_notify(this, handle, cx))
4070                                .is_ok()
4071                        } else {
4072                            false
4073                        }
4074                    })
4075                    .unwrap_or(false)
4076            }),
4077        )
4078    }
4079
4080    /// Subscribe to events emitted by another model or view.
4081    /// The entity to which you're subscribing must implement the [`EventEmitter`] trait.
4082    /// 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.
4083    pub fn subscribe<V2, E, Evt>(
4084        &mut self,
4085        entity: &E,
4086        mut on_event: impl FnMut(&mut V, E, &Evt, &mut ViewContext<'_, V>) + 'static,
4087    ) -> Subscription
4088    where
4089        V2: EventEmitter<Evt>,
4090        E: Entity<V2>,
4091        Evt: 'static,
4092    {
4093        let view = self.view().downgrade();
4094        let entity_id = entity.entity_id();
4095        let handle = entity.downgrade();
4096        let window_handle = self.window.handle;
4097        self.app.new_subscription(
4098            entity_id,
4099            (
4100                TypeId::of::<Evt>(),
4101                Box::new(move |event, cx| {
4102                    window_handle
4103                        .update(cx, |_, cx| {
4104                            if let Some(handle) = E::upgrade_from(&handle) {
4105                                let event = event.downcast_ref().expect("invalid event type");
4106                                view.update(cx, |this, cx| on_event(this, handle, event, cx))
4107                                    .is_ok()
4108                            } else {
4109                                false
4110                            }
4111                        })
4112                        .unwrap_or(false)
4113                }),
4114            ),
4115        )
4116    }
4117
4118    /// Register a callback to be invoked when the view is released.
4119    ///
4120    /// The callback receives a handle to the view's window. This handle may be
4121    /// invalid, if the window was closed before the view was released.
4122    pub fn on_release(
4123        &mut self,
4124        on_release: impl FnOnce(&mut V, AnyWindowHandle, &mut AppContext) + 'static,
4125    ) -> Subscription {
4126        let window_handle = self.window.handle;
4127        let (subscription, activate) = self.app.release_listeners.insert(
4128            self.view.model.entity_id,
4129            Box::new(move |this, cx| {
4130                let this = this.downcast_mut().expect("invalid entity type");
4131                on_release(this, window_handle, cx)
4132            }),
4133        );
4134        activate();
4135        subscription
4136    }
4137
4138    /// Register a callback to be invoked when the given Model or View is released.
4139    pub fn observe_release<V2, E>(
4140        &mut self,
4141        entity: &E,
4142        mut on_release: impl FnMut(&mut V, &mut V2, &mut ViewContext<'_, V>) + 'static,
4143    ) -> Subscription
4144    where
4145        V: 'static,
4146        V2: 'static,
4147        E: Entity<V2>,
4148    {
4149        let view = self.view().downgrade();
4150        let entity_id = entity.entity_id();
4151        let window_handle = self.window.handle;
4152        let (subscription, activate) = self.app.release_listeners.insert(
4153            entity_id,
4154            Box::new(move |entity, cx| {
4155                let entity = entity.downcast_mut().expect("invalid entity type");
4156                let _ = window_handle.update(cx, |_, cx| {
4157                    view.update(cx, |this, cx| on_release(this, entity, cx))
4158                });
4159            }),
4160        );
4161        activate();
4162        subscription
4163    }
4164
4165    /// Indicate that this view has changed, which will invoke any observers and also mark the window as dirty.
4166    /// If this view or any of its ancestors are *cached*, notifying it will cause it or its ancestors to be redrawn.
4167    pub fn notify(&mut self) {
4168        self.window_cx.notify(self.view.entity_id());
4169    }
4170
4171    /// Register a callback to be invoked when the window is resized.
4172    pub fn observe_window_bounds(
4173        &mut self,
4174        mut callback: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
4175    ) -> Subscription {
4176        let view = self.view.downgrade();
4177        let (subscription, activate) = self.window.bounds_observers.insert(
4178            (),
4179            Box::new(move |cx| view.update(cx, |view, cx| callback(view, cx)).is_ok()),
4180        );
4181        activate();
4182        subscription
4183    }
4184
4185    /// Register a callback to be invoked when the window is activated or deactivated.
4186    pub fn observe_window_activation(
4187        &mut self,
4188        mut callback: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
4189    ) -> Subscription {
4190        let view = self.view.downgrade();
4191        let (subscription, activate) = self.window.activation_observers.insert(
4192            (),
4193            Box::new(move |cx| view.update(cx, |view, cx| callback(view, cx)).is_ok()),
4194        );
4195        activate();
4196        subscription
4197    }
4198
4199    /// Registers a callback to be invoked when the window appearance changes.
4200    pub fn observe_window_appearance(
4201        &mut self,
4202        mut callback: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
4203    ) -> Subscription {
4204        let view = self.view.downgrade();
4205        let (subscription, activate) = self.window.appearance_observers.insert(
4206            (),
4207            Box::new(move |cx| view.update(cx, |view, cx| callback(view, cx)).is_ok()),
4208        );
4209        activate();
4210        subscription
4211    }
4212
4213    /// Register a callback to be invoked when the window's pending input changes.
4214    pub fn observe_pending_input(
4215        &mut self,
4216        mut callback: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
4217    ) -> Subscription {
4218        let view = self.view.downgrade();
4219        let (subscription, activate) = self.window.pending_input_observers.insert(
4220            (),
4221            Box::new(move |cx| view.update(cx, |view, cx| callback(view, cx)).is_ok()),
4222        );
4223        activate();
4224        subscription
4225    }
4226
4227    /// Register a listener to be called when the given focus handle receives focus.
4228    /// Returns a subscription and persists until the subscription is dropped.
4229    pub fn on_focus(
4230        &mut self,
4231        handle: &FocusHandle,
4232        mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
4233    ) -> Subscription {
4234        let view = self.view.downgrade();
4235        let focus_id = handle.id;
4236        let (subscription, activate) =
4237            self.window.new_focus_listener(Box::new(move |event, cx| {
4238                view.update(cx, |view, cx| {
4239                    if event.previous_focus_path.last() != Some(&focus_id)
4240                        && event.current_focus_path.last() == Some(&focus_id)
4241                    {
4242                        listener(view, cx)
4243                    }
4244                })
4245                .is_ok()
4246            }));
4247        self.app.defer(|_| activate());
4248        subscription
4249    }
4250
4251    /// Register a listener to be called when the given focus handle or one of its descendants receives focus.
4252    /// This does not fire if the given focus handle - or one of its descendants - was previously focused.
4253    /// Returns a subscription and persists until the subscription is dropped.
4254    pub fn on_focus_in(
4255        &mut self,
4256        handle: &FocusHandle,
4257        mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
4258    ) -> Subscription {
4259        let view = self.view.downgrade();
4260        let focus_id = handle.id;
4261        let (subscription, activate) =
4262            self.window.new_focus_listener(Box::new(move |event, cx| {
4263                view.update(cx, |view, cx| {
4264                    if event.is_focus_in(focus_id) {
4265                        listener(view, cx)
4266                    }
4267                })
4268                .is_ok()
4269            }));
4270        self.app.defer(move |_| activate());
4271        subscription
4272    }
4273
4274    /// Register a listener to be called when the given focus handle loses focus.
4275    /// Returns a subscription and persists until the subscription is dropped.
4276    pub fn on_blur(
4277        &mut self,
4278        handle: &FocusHandle,
4279        mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
4280    ) -> Subscription {
4281        let view = self.view.downgrade();
4282        let focus_id = handle.id;
4283        let (subscription, activate) =
4284            self.window.new_focus_listener(Box::new(move |event, cx| {
4285                view.update(cx, |view, cx| {
4286                    if event.previous_focus_path.last() == Some(&focus_id)
4287                        && event.current_focus_path.last() != Some(&focus_id)
4288                    {
4289                        listener(view, cx)
4290                    }
4291                })
4292                .is_ok()
4293            }));
4294        self.app.defer(move |_| activate());
4295        subscription
4296    }
4297
4298    /// Register a listener to be called when nothing in the window has focus.
4299    /// This typically happens when the node that was focused is removed from the tree,
4300    /// and this callback lets you chose a default place to restore the users focus.
4301    /// Returns a subscription and persists until the subscription is dropped.
4302    pub fn on_focus_lost(
4303        &mut self,
4304        mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
4305    ) -> Subscription {
4306        let view = self.view.downgrade();
4307        let (subscription, activate) = self.window.focus_lost_listeners.insert(
4308            (),
4309            Box::new(move |cx| view.update(cx, |view, cx| listener(view, cx)).is_ok()),
4310        );
4311        activate();
4312        subscription
4313    }
4314
4315    /// Register a listener to be called when the given focus handle or one of its descendants loses focus.
4316    /// Returns a subscription and persists until the subscription is dropped.
4317    pub fn on_focus_out(
4318        &mut self,
4319        handle: &FocusHandle,
4320        mut listener: impl FnMut(&mut V, FocusOutEvent, &mut ViewContext<V>) + 'static,
4321    ) -> Subscription {
4322        let view = self.view.downgrade();
4323        let focus_id = handle.id;
4324        let (subscription, activate) =
4325            self.window.new_focus_listener(Box::new(move |event, cx| {
4326                view.update(cx, |view, cx| {
4327                    if let Some(blurred_id) = event.previous_focus_path.last().copied() {
4328                        if event.is_focus_out(focus_id) {
4329                            let event = FocusOutEvent {
4330                                blurred: WeakFocusHandle {
4331                                    id: blurred_id,
4332                                    handles: Arc::downgrade(&cx.window.focus_handles),
4333                                },
4334                            };
4335                            listener(view, event, cx)
4336                        }
4337                    }
4338                })
4339                .is_ok()
4340            }));
4341        self.app.defer(move |_| activate());
4342        subscription
4343    }
4344
4345    /// Schedule a future to be run asynchronously.
4346    /// The given callback is invoked with a [`WeakView<V>`] to avoid leaking the view for a long-running process.
4347    /// It's also given an [`AsyncWindowContext`], which can be used to access the state of the view across await points.
4348    /// The returned future will be polled on the main thread.
4349    pub fn spawn<Fut, R>(
4350        &mut self,
4351        f: impl FnOnce(WeakView<V>, AsyncWindowContext) -> Fut,
4352    ) -> Task<R>
4353    where
4354        R: 'static,
4355        Fut: Future<Output = R> + 'static,
4356    {
4357        let view = self.view().downgrade();
4358        self.window_cx.spawn(|cx| f(view, cx))
4359    }
4360
4361    /// Register a callback to be invoked when the given global state changes.
4362    pub fn observe_global<G: Global>(
4363        &mut self,
4364        mut f: impl FnMut(&mut V, &mut ViewContext<'_, V>) + 'static,
4365    ) -> Subscription {
4366        let window_handle = self.window.handle;
4367        let view = self.view().downgrade();
4368        let (subscription, activate) = self.global_observers.insert(
4369            TypeId::of::<G>(),
4370            Box::new(move |cx| {
4371                window_handle
4372                    .update(cx, |_, cx| view.update(cx, |view, cx| f(view, cx)).is_ok())
4373                    .unwrap_or(false)
4374            }),
4375        );
4376        self.app.defer(move |_| activate());
4377        subscription
4378    }
4379
4380    /// Register a callback to be invoked when the given Action type is dispatched to the window.
4381    pub fn on_action(
4382        &mut self,
4383        action_type: TypeId,
4384        listener: impl Fn(&mut V, &dyn Any, DispatchPhase, &mut ViewContext<V>) + 'static,
4385    ) {
4386        let handle = self.view().clone();
4387        self.window_cx
4388            .on_action(action_type, move |action, phase, cx| {
4389                handle.update(cx, |view, cx| {
4390                    listener(view, action, phase, cx);
4391                })
4392            });
4393    }
4394
4395    /// Emit an event to be handled by any other views that have subscribed via [ViewContext::subscribe].
4396    pub fn emit<Evt>(&mut self, event: Evt)
4397    where
4398        Evt: 'static,
4399        V: EventEmitter<Evt>,
4400    {
4401        let emitter = self.view.model.entity_id;
4402        self.app.push_effect(Effect::Emit {
4403            emitter,
4404            event_type: TypeId::of::<Evt>(),
4405            event: Box::new(event),
4406        });
4407    }
4408
4409    /// Move focus to the current view, assuming it implements [`FocusableView`].
4410    pub fn focus_self(&mut self)
4411    where
4412        V: FocusableView,
4413    {
4414        self.defer(|view, cx| view.focus_handle(cx).focus(cx))
4415    }
4416
4417    /// Convenience method for accessing view state in an event callback.
4418    ///
4419    /// Many GPUI callbacks take the form of `Fn(&E, &mut WindowContext)`,
4420    /// but it's often useful to be able to access view state in these
4421    /// callbacks. This method provides a convenient way to do so.
4422    pub fn listener<E>(
4423        &self,
4424        f: impl Fn(&mut V, &E, &mut ViewContext<V>) + 'static,
4425    ) -> impl Fn(&E, &mut WindowContext) + 'static {
4426        let view = self.view().downgrade();
4427        move |e: &E, cx: &mut WindowContext| {
4428            view.update(cx, |view, cx| f(view, e, cx)).ok();
4429        }
4430    }
4431}
4432
4433impl<V> Context for ViewContext<'_, V> {
4434    type Result<U> = U;
4435
4436    fn new_model<T: 'static>(
4437        &mut self,
4438        build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
4439    ) -> Model<T> {
4440        self.window_cx.new_model(build_model)
4441    }
4442
4443    fn reserve_model<T: 'static>(&mut self) -> Self::Result<crate::Reservation<T>> {
4444        self.window_cx.reserve_model()
4445    }
4446
4447    fn insert_model<T: 'static>(
4448        &mut self,
4449        reservation: crate::Reservation<T>,
4450        build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
4451    ) -> Self::Result<Model<T>> {
4452        self.window_cx.insert_model(reservation, build_model)
4453    }
4454
4455    fn update_model<T: 'static, R>(
4456        &mut self,
4457        model: &Model<T>,
4458        update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
4459    ) -> R {
4460        self.window_cx.update_model(model, update)
4461    }
4462
4463    fn read_model<T, R>(
4464        &self,
4465        handle: &Model<T>,
4466        read: impl FnOnce(&T, &AppContext) -> R,
4467    ) -> Self::Result<R>
4468    where
4469        T: 'static,
4470    {
4471        self.window_cx.read_model(handle, read)
4472    }
4473
4474    fn update_window<T, F>(&mut self, window: AnyWindowHandle, update: F) -> Result<T>
4475    where
4476        F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
4477    {
4478        self.window_cx.update_window(window, update)
4479    }
4480
4481    fn read_window<T, R>(
4482        &self,
4483        window: &WindowHandle<T>,
4484        read: impl FnOnce(View<T>, &AppContext) -> R,
4485    ) -> Result<R>
4486    where
4487        T: 'static,
4488    {
4489        self.window_cx.read_window(window, read)
4490    }
4491}
4492
4493impl<V: 'static> VisualContext for ViewContext<'_, V> {
4494    fn new_view<W: Render + 'static>(
4495        &mut self,
4496        build_view_state: impl FnOnce(&mut ViewContext<'_, W>) -> W,
4497    ) -> Self::Result<View<W>> {
4498        self.window_cx.new_view(build_view_state)
4499    }
4500
4501    fn update_view<V2: 'static, R>(
4502        &mut self,
4503        view: &View<V2>,
4504        update: impl FnOnce(&mut V2, &mut ViewContext<'_, V2>) -> R,
4505    ) -> Self::Result<R> {
4506        self.window_cx.update_view(view, update)
4507    }
4508
4509    fn replace_root_view<W>(
4510        &mut self,
4511        build_view: impl FnOnce(&mut ViewContext<'_, W>) -> W,
4512    ) -> Self::Result<View<W>>
4513    where
4514        W: 'static + Render,
4515    {
4516        self.window_cx.replace_root_view(build_view)
4517    }
4518
4519    fn focus_view<W: FocusableView>(&mut self, view: &View<W>) -> Self::Result<()> {
4520        self.window_cx.focus_view(view)
4521    }
4522
4523    fn dismiss_view<W: ManagedView>(&mut self, view: &View<W>) -> Self::Result<()> {
4524        self.window_cx.dismiss_view(view)
4525    }
4526}
4527
4528impl<'a, V> std::ops::Deref for ViewContext<'a, V> {
4529    type Target = WindowContext<'a>;
4530
4531    fn deref(&self) -> &Self::Target {
4532        &self.window_cx
4533    }
4534}
4535
4536impl<'a, V> std::ops::DerefMut for ViewContext<'a, V> {
4537    fn deref_mut(&mut self) -> &mut Self::Target {
4538        &mut self.window_cx
4539    }
4540}
4541
4542// #[derive(Clone, Copy, Eq, PartialEq, Hash)]
4543slotmap::new_key_type! {
4544    /// A unique identifier for a window.
4545    pub struct WindowId;
4546}
4547
4548impl WindowId {
4549    /// Converts this window ID to a `u64`.
4550    pub fn as_u64(&self) -> u64 {
4551        self.0.as_ffi()
4552    }
4553}
4554
4555/// A handle to a window with a specific root view type.
4556/// Note that this does not keep the window alive on its own.
4557#[derive(Deref, DerefMut)]
4558pub struct WindowHandle<V> {
4559    #[deref]
4560    #[deref_mut]
4561    pub(crate) any_handle: AnyWindowHandle,
4562    state_type: PhantomData<V>,
4563}
4564
4565impl<V: 'static + Render> WindowHandle<V> {
4566    /// Creates a new handle from a window ID.
4567    /// This does not check if the root type of the window is `V`.
4568    pub fn new(id: WindowId) -> Self {
4569        WindowHandle {
4570            any_handle: AnyWindowHandle {
4571                id,
4572                state_type: TypeId::of::<V>(),
4573            },
4574            state_type: PhantomData,
4575        }
4576    }
4577
4578    /// Get the root view out of this window.
4579    ///
4580    /// This will fail if the window is closed or if the root view's type does not match `V`.
4581    pub fn root<C>(&self, cx: &mut C) -> Result<View<V>>
4582    where
4583        C: Context,
4584    {
4585        Flatten::flatten(cx.update_window(self.any_handle, |root_view, _| {
4586            root_view
4587                .downcast::<V>()
4588                .map_err(|_| anyhow!("the type of the window's root view has changed"))
4589        }))
4590    }
4591
4592    /// Updates the root view of this window.
4593    ///
4594    /// This will fail if the window has been closed or if the root view's type does not match
4595    pub fn update<C, R>(
4596        &self,
4597        cx: &mut C,
4598        update: impl FnOnce(&mut V, &mut ViewContext<'_, V>) -> R,
4599    ) -> Result<R>
4600    where
4601        C: Context,
4602    {
4603        cx.update_window(self.any_handle, |root_view, cx| {
4604            let view = root_view
4605                .downcast::<V>()
4606                .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
4607            Ok(cx.update_view(&view, update))
4608        })?
4609    }
4610
4611    /// Read the root view out of this window.
4612    ///
4613    /// This will fail if the window is closed or if the root view's type does not match `V`.
4614    pub fn read<'a>(&self, cx: &'a AppContext) -> Result<&'a V> {
4615        let x = cx
4616            .windows
4617            .get(self.id)
4618            .and_then(|window| {
4619                window
4620                    .as_ref()
4621                    .and_then(|window| window.root_view.clone())
4622                    .map(|root_view| root_view.downcast::<V>())
4623            })
4624            .ok_or_else(|| anyhow!("window not found"))?
4625            .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
4626
4627        Ok(x.read(cx))
4628    }
4629
4630    /// Read the root view out of this window, with a callback
4631    ///
4632    /// This will fail if the window is closed or if the root view's type does not match `V`.
4633    pub fn read_with<C, R>(&self, cx: &C, read_with: impl FnOnce(&V, &AppContext) -> R) -> Result<R>
4634    where
4635        C: Context,
4636    {
4637        cx.read_window(self, |root_view, cx| read_with(root_view.read(cx), cx))
4638    }
4639
4640    /// Read the root view pointer off of this window.
4641    ///
4642    /// This will fail if the window is closed or if the root view's type does not match `V`.
4643    pub fn root_view<C>(&self, cx: &C) -> Result<View<V>>
4644    where
4645        C: Context,
4646    {
4647        cx.read_window(self, |root_view, _cx| root_view.clone())
4648    }
4649
4650    /// Check if this window is 'active'.
4651    ///
4652    /// Will return `None` if the window is closed or currently
4653    /// borrowed.
4654    pub fn is_active(&self, cx: &mut AppContext) -> Option<bool> {
4655        cx.update_window(self.any_handle, |_, cx| cx.is_window_active())
4656            .ok()
4657    }
4658}
4659
4660impl<V> Copy for WindowHandle<V> {}
4661
4662impl<V> Clone for WindowHandle<V> {
4663    fn clone(&self) -> Self {
4664        *self
4665    }
4666}
4667
4668impl<V> PartialEq for WindowHandle<V> {
4669    fn eq(&self, other: &Self) -> bool {
4670        self.any_handle == other.any_handle
4671    }
4672}
4673
4674impl<V> Eq for WindowHandle<V> {}
4675
4676impl<V> Hash for WindowHandle<V> {
4677    fn hash<H: Hasher>(&self, state: &mut H) {
4678        self.any_handle.hash(state);
4679    }
4680}
4681
4682impl<V: 'static> From<WindowHandle<V>> for AnyWindowHandle {
4683    fn from(val: WindowHandle<V>) -> Self {
4684        val.any_handle
4685    }
4686}
4687
4688unsafe impl<V> Send for WindowHandle<V> {}
4689unsafe impl<V> Sync for WindowHandle<V> {}
4690
4691/// A handle to a window with any root view type, which can be downcast to a window with a specific root view type.
4692#[derive(Copy, Clone, PartialEq, Eq, Hash)]
4693pub struct AnyWindowHandle {
4694    pub(crate) id: WindowId,
4695    state_type: TypeId,
4696}
4697
4698impl AnyWindowHandle {
4699    /// Get the ID of this window.
4700    pub fn window_id(&self) -> WindowId {
4701        self.id
4702    }
4703
4704    /// Attempt to convert this handle to a window handle with a specific root view type.
4705    /// If the types do not match, this will return `None`.
4706    pub fn downcast<T: 'static>(&self) -> Option<WindowHandle<T>> {
4707        if TypeId::of::<T>() == self.state_type {
4708            Some(WindowHandle {
4709                any_handle: *self,
4710                state_type: PhantomData,
4711            })
4712        } else {
4713            None
4714        }
4715    }
4716
4717    /// Updates the state of the root view of this window.
4718    ///
4719    /// This will fail if the window has been closed.
4720    pub fn update<C, R>(
4721        self,
4722        cx: &mut C,
4723        update: impl FnOnce(AnyView, &mut WindowContext<'_>) -> R,
4724    ) -> Result<R>
4725    where
4726        C: Context,
4727    {
4728        cx.update_window(self, update)
4729    }
4730
4731    /// Read the state of the root view of this window.
4732    ///
4733    /// This will fail if the window has been closed.
4734    pub fn read<T, C, R>(self, cx: &C, read: impl FnOnce(View<T>, &AppContext) -> R) -> Result<R>
4735    where
4736        C: Context,
4737        T: 'static,
4738    {
4739        let view = self
4740            .downcast::<T>()
4741            .context("the type of the window's root view has changed")?;
4742
4743        cx.read_window(&view, read)
4744    }
4745}
4746
4747/// An identifier for an [`Element`](crate::Element).
4748///
4749/// Can be constructed with a string, a number, or both, as well
4750/// as other internal representations.
4751#[derive(Clone, Debug, Eq, PartialEq, Hash)]
4752pub enum ElementId {
4753    /// The ID of a View element
4754    View(EntityId),
4755    /// An integer ID.
4756    Integer(usize),
4757    /// A string based ID.
4758    Name(SharedString),
4759    /// A UUID.
4760    Uuid(Uuid),
4761    /// An ID that's equated with a focus handle.
4762    FocusHandle(FocusId),
4763    /// A combination of a name and an integer.
4764    NamedInteger(SharedString, usize),
4765}
4766
4767impl Display for ElementId {
4768    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
4769        match self {
4770            ElementId::View(entity_id) => write!(f, "view-{}", entity_id)?,
4771            ElementId::Integer(ix) => write!(f, "{}", ix)?,
4772            ElementId::Name(name) => write!(f, "{}", name)?,
4773            ElementId::FocusHandle(_) => write!(f, "FocusHandle")?,
4774            ElementId::NamedInteger(s, i) => write!(f, "{}-{}", s, i)?,
4775            ElementId::Uuid(uuid) => write!(f, "{}", uuid)?,
4776        }
4777
4778        Ok(())
4779    }
4780}
4781
4782impl TryInto<SharedString> for ElementId {
4783    type Error = anyhow::Error;
4784
4785    fn try_into(self) -> anyhow::Result<SharedString> {
4786        if let ElementId::Name(name) = self {
4787            Ok(name)
4788        } else {
4789            Err(anyhow!("element id is not string"))
4790        }
4791    }
4792}
4793
4794impl From<usize> for ElementId {
4795    fn from(id: usize) -> Self {
4796        ElementId::Integer(id)
4797    }
4798}
4799
4800impl From<i32> for ElementId {
4801    fn from(id: i32) -> Self {
4802        Self::Integer(id as usize)
4803    }
4804}
4805
4806impl From<SharedString> for ElementId {
4807    fn from(name: SharedString) -> Self {
4808        ElementId::Name(name)
4809    }
4810}
4811
4812impl From<&'static str> for ElementId {
4813    fn from(name: &'static str) -> Self {
4814        ElementId::Name(name.into())
4815    }
4816}
4817
4818impl<'a> From<&'a FocusHandle> for ElementId {
4819    fn from(handle: &'a FocusHandle) -> Self {
4820        ElementId::FocusHandle(handle.id)
4821    }
4822}
4823
4824impl From<(&'static str, EntityId)> for ElementId {
4825    fn from((name, id): (&'static str, EntityId)) -> Self {
4826        ElementId::NamedInteger(name.into(), id.as_u64() as usize)
4827    }
4828}
4829
4830impl From<(&'static str, usize)> for ElementId {
4831    fn from((name, id): (&'static str, usize)) -> Self {
4832        ElementId::NamedInteger(name.into(), id)
4833    }
4834}
4835
4836impl From<(&'static str, u64)> for ElementId {
4837    fn from((name, id): (&'static str, u64)) -> Self {
4838        ElementId::NamedInteger(name.into(), id as usize)
4839    }
4840}
4841
4842impl From<Uuid> for ElementId {
4843    fn from(value: Uuid) -> Self {
4844        Self::Uuid(value)
4845    }
4846}
4847
4848impl From<(&'static str, u32)> for ElementId {
4849    fn from((name, id): (&'static str, u32)) -> Self {
4850        ElementId::NamedInteger(name.into(), id as usize)
4851    }
4852}
4853
4854/// A rectangle to be rendered in the window at the given position and size.
4855/// Passed as an argument [`WindowContext::paint_quad`].
4856#[derive(Clone)]
4857pub struct PaintQuad {
4858    /// The bounds of the quad within the window.
4859    pub bounds: Bounds<Pixels>,
4860    /// The radii of the quad's corners.
4861    pub corner_radii: Corners<Pixels>,
4862    /// The background color of the quad.
4863    pub background: Hsla,
4864    /// The widths of the quad's borders.
4865    pub border_widths: Edges<Pixels>,
4866    /// The color of the quad's borders.
4867    pub border_color: Hsla,
4868}
4869
4870impl PaintQuad {
4871    /// Sets the corner radii of the quad.
4872    pub fn corner_radii(self, corner_radii: impl Into<Corners<Pixels>>) -> Self {
4873        PaintQuad {
4874            corner_radii: corner_radii.into(),
4875            ..self
4876        }
4877    }
4878
4879    /// Sets the border widths of the quad.
4880    pub fn border_widths(self, border_widths: impl Into<Edges<Pixels>>) -> Self {
4881        PaintQuad {
4882            border_widths: border_widths.into(),
4883            ..self
4884        }
4885    }
4886
4887    /// Sets the border color of the quad.
4888    pub fn border_color(self, border_color: impl Into<Hsla>) -> Self {
4889        PaintQuad {
4890            border_color: border_color.into(),
4891            ..self
4892        }
4893    }
4894
4895    /// Sets the background color of the quad.
4896    pub fn background(self, background: impl Into<Hsla>) -> Self {
4897        PaintQuad {
4898            background: background.into(),
4899            ..self
4900        }
4901    }
4902}
4903
4904/// Creates a quad with the given parameters.
4905pub fn quad(
4906    bounds: Bounds<Pixels>,
4907    corner_radii: impl Into<Corners<Pixels>>,
4908    background: impl Into<Hsla>,
4909    border_widths: impl Into<Edges<Pixels>>,
4910    border_color: impl Into<Hsla>,
4911) -> PaintQuad {
4912    PaintQuad {
4913        bounds,
4914        corner_radii: corner_radii.into(),
4915        background: background.into(),
4916        border_widths: border_widths.into(),
4917        border_color: border_color.into(),
4918    }
4919}
4920
4921/// Creates a filled quad with the given bounds and background color.
4922pub fn fill(bounds: impl Into<Bounds<Pixels>>, background: impl Into<Hsla>) -> PaintQuad {
4923    PaintQuad {
4924        bounds: bounds.into(),
4925        corner_radii: (0.).into(),
4926        background: background.into(),
4927        border_widths: (0.).into(),
4928        border_color: transparent_black(),
4929    }
4930}
4931
4932/// Creates a rectangle outline with the given bounds, border color, and a 1px border width
4933pub fn outline(bounds: impl Into<Bounds<Pixels>>, border_color: impl Into<Hsla>) -> PaintQuad {
4934    PaintQuad {
4935        bounds: bounds.into(),
4936        corner_radii: (0.).into(),
4937        background: transparent_black(),
4938        border_widths: (1.).into(),
4939        border_color: border_color.into(),
4940    }
4941}