window.rs

   1#[cfg(any(feature = "inspector", debug_assertions))]
   2use crate::Inspector;
   3use crate::{
   4    Action, AnyDrag, AnyElement, AnyImageCache, AnyTooltip, AnyView, App, AppContext, Arena, Asset,
   5    AsyncWindowContext, AvailableSpace, Background, BorderStyle, Bounds, BoxShadow, Capslock,
   6    Context, Corners, CursorStyle, Decorations, DevicePixels, DispatchActionListener,
   7    DispatchNodeId, DispatchTree, DisplayId, Edges, Effect, Entity, EntityId, EventEmitter,
   8    FileDropEvent, FontId, Global, GlobalElementId, GlyphId, GpuSpecs, Hsla, InputHandler, IsZero,
   9    KeyBinding, KeyContext, KeyDownEvent, KeyEvent, Keystroke, KeystrokeEvent, LayoutId,
  10    LineLayoutIndex, Modifiers, ModifiersChangedEvent, MonochromeSprite, MouseButton, MouseEvent,
  11    MouseMoveEvent, MouseUpEvent, Path, Pixels, PlatformAtlas, PlatformDisplay, PlatformInput,
  12    PlatformInputHandler, PlatformWindow, Point, PolychromeSprite, PromptButton, PromptLevel, Quad,
  13    Render, RenderGlyphParams, RenderImage, RenderImageParams, RenderSvgParams, Replay, ResizeEdge,
  14    SMOOTH_SVG_SCALE_FACTOR, SUBPIXEL_VARIANTS, ScaledPixels, Scene, Shadow, SharedString, Size,
  15    StrikethroughStyle, Style, SubscriberSet, Subscription, TaffyLayoutEngine, Task, TextStyle,
  16    TextStyleRefinement, TransformationMatrix, Underline, UnderlineStyle, WindowAppearance,
  17    WindowBackgroundAppearance, WindowBounds, WindowControls, WindowDecorations, WindowOptions,
  18    WindowParams, WindowTextSystem, point, prelude::*, px, rems, size, transparent_black,
  19};
  20use anyhow::{Context as _, Result, anyhow};
  21use collections::{FxHashMap, FxHashSet};
  22#[cfg(target_os = "macos")]
  23use core_video::pixel_buffer::CVPixelBuffer;
  24use derive_more::{Deref, DerefMut};
  25use futures::FutureExt;
  26use futures::channel::oneshot;
  27use itertools::FoldWhile::{Continue, Done};
  28use itertools::Itertools;
  29use parking_lot::RwLock;
  30use raw_window_handle::{HandleError, HasDisplayHandle, HasWindowHandle};
  31use refineable::Refineable;
  32use slotmap::SlotMap;
  33use smallvec::SmallVec;
  34use std::{
  35    any::{Any, TypeId},
  36    borrow::Cow,
  37    cell::{Cell, RefCell},
  38    cmp,
  39    fmt::{Debug, Display},
  40    hash::{Hash, Hasher},
  41    marker::PhantomData,
  42    mem,
  43    ops::{DerefMut, Range},
  44    rc::Rc,
  45    sync::{
  46        Arc, Weak,
  47        atomic::{AtomicUsize, Ordering::SeqCst},
  48    },
  49    time::{Duration, Instant},
  50};
  51use util::post_inc;
  52use util::{ResultExt, measure};
  53use uuid::Uuid;
  54
  55mod prompts;
  56
  57use crate::util::atomic_incr_if_not_zero;
  58pub use prompts::*;
  59
  60pub(crate) const DEFAULT_WINDOW_SIZE: Size<Pixels> = size(px(1024.), px(700.));
  61
  62/// Represents the two different phases when dispatching events.
  63#[derive(Default, Copy, Clone, Debug, Eq, PartialEq)]
  64pub enum DispatchPhase {
  65    /// After the capture phase comes the bubble phase, in which mouse event listeners are
  66    /// invoked front to back and keyboard event listeners are invoked from the focused element
  67    /// to the root of the element tree. This is the phase you'll most commonly want to use when
  68    /// registering event listeners.
  69    #[default]
  70    Bubble,
  71    /// During the initial capture phase, mouse event listeners are invoked back to front, and keyboard
  72    /// listeners are invoked from the root of the tree downward toward the focused element. This phase
  73    /// is used for special purposes such as clearing the "pressed" state for click events. If
  74    /// you stop event propagation during this phase, you need to know what you're doing. Handlers
  75    /// outside of the immediate region may rely on detecting non-local events during this phase.
  76    Capture,
  77}
  78
  79impl DispatchPhase {
  80    /// Returns true if this represents the "bubble" phase.
  81    pub fn bubble(self) -> bool {
  82        self == DispatchPhase::Bubble
  83    }
  84
  85    /// Returns true if this represents the "capture" phase.
  86    pub fn capture(self) -> bool {
  87        self == DispatchPhase::Capture
  88    }
  89}
  90
  91struct WindowInvalidatorInner {
  92    pub dirty: bool,
  93    pub draw_phase: DrawPhase,
  94    pub dirty_views: FxHashSet<EntityId>,
  95}
  96
  97#[derive(Clone)]
  98pub(crate) struct WindowInvalidator {
  99    inner: Rc<RefCell<WindowInvalidatorInner>>,
 100}
 101
 102impl WindowInvalidator {
 103    pub fn new() -> Self {
 104        WindowInvalidator {
 105            inner: Rc::new(RefCell::new(WindowInvalidatorInner {
 106                dirty: true,
 107                draw_phase: DrawPhase::None,
 108                dirty_views: FxHashSet::default(),
 109            })),
 110        }
 111    }
 112
 113    pub fn invalidate_view(&self, entity: EntityId, cx: &mut App) -> bool {
 114        let mut inner = self.inner.borrow_mut();
 115        inner.dirty_views.insert(entity);
 116        if inner.draw_phase == DrawPhase::None {
 117            inner.dirty = true;
 118            cx.push_effect(Effect::Notify { emitter: entity });
 119            true
 120        } else {
 121            false
 122        }
 123    }
 124
 125    pub fn is_dirty(&self) -> bool {
 126        self.inner.borrow().dirty
 127    }
 128
 129    pub fn set_dirty(&self, dirty: bool) {
 130        self.inner.borrow_mut().dirty = dirty
 131    }
 132
 133    pub fn set_phase(&self, phase: DrawPhase) {
 134        self.inner.borrow_mut().draw_phase = phase
 135    }
 136
 137    pub fn take_views(&self) -> FxHashSet<EntityId> {
 138        mem::take(&mut self.inner.borrow_mut().dirty_views)
 139    }
 140
 141    pub fn replace_views(&self, views: FxHashSet<EntityId>) {
 142        self.inner.borrow_mut().dirty_views = views;
 143    }
 144
 145    pub fn not_drawing(&self) -> bool {
 146        self.inner.borrow().draw_phase == DrawPhase::None
 147    }
 148
 149    #[track_caller]
 150    pub fn debug_assert_paint(&self) {
 151        debug_assert!(
 152            matches!(self.inner.borrow().draw_phase, DrawPhase::Paint),
 153            "this method can only be called during paint"
 154        );
 155    }
 156
 157    #[track_caller]
 158    pub fn debug_assert_prepaint(&self) {
 159        debug_assert!(
 160            matches!(self.inner.borrow().draw_phase, DrawPhase::Prepaint),
 161            "this method can only be called during request_layout, or prepaint"
 162        );
 163    }
 164
 165    #[track_caller]
 166    pub fn debug_assert_paint_or_prepaint(&self) {
 167        debug_assert!(
 168            matches!(
 169                self.inner.borrow().draw_phase,
 170                DrawPhase::Paint | DrawPhase::Prepaint
 171            ),
 172            "this method can only be called during request_layout, prepaint, or paint"
 173        );
 174    }
 175}
 176
 177type AnyObserver = Box<dyn FnMut(&mut Window, &mut App) -> bool + 'static>;
 178
 179pub(crate) type AnyWindowFocusListener =
 180    Box<dyn FnMut(&WindowFocusEvent, &mut Window, &mut App) -> bool + 'static>;
 181
 182pub(crate) struct WindowFocusEvent {
 183    pub(crate) previous_focus_path: SmallVec<[FocusId; 8]>,
 184    pub(crate) current_focus_path: SmallVec<[FocusId; 8]>,
 185}
 186
 187impl WindowFocusEvent {
 188    pub fn is_focus_in(&self, focus_id: FocusId) -> bool {
 189        !self.previous_focus_path.contains(&focus_id) && self.current_focus_path.contains(&focus_id)
 190    }
 191
 192    pub fn is_focus_out(&self, focus_id: FocusId) -> bool {
 193        self.previous_focus_path.contains(&focus_id) && !self.current_focus_path.contains(&focus_id)
 194    }
 195}
 196
 197/// This is provided when subscribing for `Context::on_focus_out` events.
 198pub struct FocusOutEvent {
 199    /// A weak focus handle representing what was blurred.
 200    pub blurred: WeakFocusHandle,
 201}
 202
 203slotmap::new_key_type! {
 204    /// A globally unique identifier for a focusable element.
 205    pub struct FocusId;
 206}
 207
 208thread_local! {
 209    pub(crate) static ELEMENT_ARENA: RefCell<Arena> = RefCell::new(Arena::new(1024 * 1024));
 210}
 211
 212/// Returned when the element arena has been used and so must be cleared before the next draw.
 213#[must_use]
 214pub struct ArenaClearNeeded;
 215
 216impl ArenaClearNeeded {
 217    /// Clear the element arena.
 218    pub fn clear(self) {
 219        ELEMENT_ARENA.with_borrow_mut(|element_arena| {
 220            element_arena.clear();
 221        });
 222    }
 223}
 224
 225pub(crate) type FocusMap = RwLock<SlotMap<FocusId, AtomicUsize>>;
 226
 227impl FocusId {
 228    /// Obtains whether the element associated with this handle is currently focused.
 229    pub fn is_focused(&self, window: &Window) -> bool {
 230        window.focus == Some(*self)
 231    }
 232
 233    /// Obtains whether the element associated with this handle contains the focused
 234    /// element or is itself focused.
 235    pub fn contains_focused(&self, window: &Window, cx: &App) -> bool {
 236        window
 237            .focused(cx)
 238            .map_or(false, |focused| self.contains(focused.id, window))
 239    }
 240
 241    /// Obtains whether the element associated with this handle is contained within the
 242    /// focused element or is itself focused.
 243    pub fn within_focused(&self, window: &Window, cx: &App) -> bool {
 244        let focused = window.focused(cx);
 245        focused.map_or(false, |focused| focused.id.contains(*self, window))
 246    }
 247
 248    /// Obtains whether this handle contains the given handle in the most recently rendered frame.
 249    pub(crate) fn contains(&self, other: Self, window: &Window) -> bool {
 250        window
 251            .rendered_frame
 252            .dispatch_tree
 253            .focus_contains(*self, other)
 254    }
 255}
 256
 257/// A handle which can be used to track and manipulate the focused element in a window.
 258pub struct FocusHandle {
 259    pub(crate) id: FocusId,
 260    handles: Arc<FocusMap>,
 261}
 262
 263impl std::fmt::Debug for FocusHandle {
 264    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 265        f.write_fmt(format_args!("FocusHandle({:?})", self.id))
 266    }
 267}
 268
 269impl FocusHandle {
 270    pub(crate) fn new(handles: &Arc<FocusMap>) -> Self {
 271        let id = handles.write().insert(AtomicUsize::new(1));
 272        Self {
 273            id,
 274            handles: handles.clone(),
 275        }
 276    }
 277
 278    pub(crate) fn for_id(id: FocusId, handles: &Arc<FocusMap>) -> Option<Self> {
 279        let lock = handles.read();
 280        let ref_count = lock.get(id)?;
 281        if atomic_incr_if_not_zero(ref_count) == 0 {
 282            return None;
 283        }
 284        Some(Self {
 285            id,
 286            handles: handles.clone(),
 287        })
 288    }
 289
 290    /// Converts this focus handle into a weak variant, which does not prevent it from being released.
 291    pub fn downgrade(&self) -> WeakFocusHandle {
 292        WeakFocusHandle {
 293            id: self.id,
 294            handles: Arc::downgrade(&self.handles),
 295        }
 296    }
 297
 298    /// Moves the focus to the element associated with this handle.
 299    pub fn focus(&self, window: &mut Window) {
 300        window.focus(self)
 301    }
 302
 303    /// Obtains whether the element associated with this handle is currently focused.
 304    pub fn is_focused(&self, window: &Window) -> bool {
 305        self.id.is_focused(window)
 306    }
 307
 308    /// Obtains whether the element associated with this handle contains the focused
 309    /// element or is itself focused.
 310    pub fn contains_focused(&self, window: &Window, cx: &App) -> bool {
 311        self.id.contains_focused(window, cx)
 312    }
 313
 314    /// Obtains whether the element associated with this handle is contained within the
 315    /// focused element or is itself focused.
 316    pub fn within_focused(&self, window: &Window, cx: &mut App) -> bool {
 317        self.id.within_focused(window, cx)
 318    }
 319
 320    /// Obtains whether this handle contains the given handle in the most recently rendered frame.
 321    pub fn contains(&self, other: &Self, window: &Window) -> bool {
 322        self.id.contains(other.id, window)
 323    }
 324
 325    /// Dispatch an action on the element that rendered this focus handle
 326    pub fn dispatch_action(&self, action: &dyn Action, window: &mut Window, cx: &mut App) {
 327        if let Some(node_id) = window
 328            .rendered_frame
 329            .dispatch_tree
 330            .focusable_node_id(self.id)
 331        {
 332            window.dispatch_action_on_node(node_id, action, cx)
 333        }
 334    }
 335}
 336
 337impl Clone for FocusHandle {
 338    fn clone(&self) -> Self {
 339        Self::for_id(self.id, &self.handles).unwrap()
 340    }
 341}
 342
 343impl PartialEq for FocusHandle {
 344    fn eq(&self, other: &Self) -> bool {
 345        self.id == other.id
 346    }
 347}
 348
 349impl Eq for FocusHandle {}
 350
 351impl Drop for FocusHandle {
 352    fn drop(&mut self) {
 353        self.handles
 354            .read()
 355            .get(self.id)
 356            .unwrap()
 357            .fetch_sub(1, SeqCst);
 358    }
 359}
 360
 361/// A weak reference to a focus handle.
 362#[derive(Clone, Debug)]
 363pub struct WeakFocusHandle {
 364    pub(crate) id: FocusId,
 365    pub(crate) handles: Weak<FocusMap>,
 366}
 367
 368impl WeakFocusHandle {
 369    /// Attempts to upgrade the [WeakFocusHandle] to a [FocusHandle].
 370    pub fn upgrade(&self) -> Option<FocusHandle> {
 371        let handles = self.handles.upgrade()?;
 372        FocusHandle::for_id(self.id, &handles)
 373    }
 374}
 375
 376impl PartialEq for WeakFocusHandle {
 377    fn eq(&self, other: &WeakFocusHandle) -> bool {
 378        self.id == other.id
 379    }
 380}
 381
 382impl Eq for WeakFocusHandle {}
 383
 384impl PartialEq<FocusHandle> for WeakFocusHandle {
 385    fn eq(&self, other: &FocusHandle) -> bool {
 386        self.id == other.id
 387    }
 388}
 389
 390impl PartialEq<WeakFocusHandle> for FocusHandle {
 391    fn eq(&self, other: &WeakFocusHandle) -> bool {
 392        self.id == other.id
 393    }
 394}
 395
 396/// Focusable allows users of your view to easily
 397/// focus it (using window.focus_view(cx, view))
 398pub trait Focusable: 'static {
 399    /// Returns the focus handle associated with this view.
 400    fn focus_handle(&self, cx: &App) -> FocusHandle;
 401}
 402
 403impl<V: Focusable> Focusable for Entity<V> {
 404    fn focus_handle(&self, cx: &App) -> FocusHandle {
 405        self.read(cx).focus_handle(cx)
 406    }
 407}
 408
 409/// ManagedView is a view (like a Modal, Popover, Menu, etc.)
 410/// where the lifecycle of the view is handled by another view.
 411pub trait ManagedView: Focusable + EventEmitter<DismissEvent> + Render {}
 412
 413impl<M: Focusable + EventEmitter<DismissEvent> + Render> ManagedView for M {}
 414
 415/// Emitted by implementers of [`ManagedView`] to indicate the view should be dismissed, such as when a view is presented as a modal.
 416pub struct DismissEvent;
 417
 418type FrameCallback = Box<dyn FnOnce(&mut Window, &mut App)>;
 419
 420pub(crate) type AnyMouseListener =
 421    Box<dyn FnMut(&dyn Any, DispatchPhase, &mut Window, &mut App) + 'static>;
 422
 423#[derive(Clone)]
 424pub(crate) struct CursorStyleRequest {
 425    pub(crate) hitbox_id: Option<HitboxId>,
 426    pub(crate) style: CursorStyle,
 427}
 428
 429#[derive(Default, Eq, PartialEq)]
 430pub(crate) struct HitTest {
 431    pub(crate) ids: SmallVec<[HitboxId; 8]>,
 432    pub(crate) hover_hitbox_count: usize,
 433}
 434
 435/// A type of window control area that corresponds to the platform window.
 436#[derive(Clone, Copy, Debug, Eq, PartialEq)]
 437pub enum WindowControlArea {
 438    /// An area that allows dragging of the platform window.
 439    Drag,
 440    /// An area that allows closing of the platform window.
 441    Close,
 442    /// An area that allows maximizing of the platform window.
 443    Max,
 444    /// An area that allows minimizing of the platform window.
 445    Min,
 446}
 447
 448/// An identifier for a [Hitbox] which also includes [HitboxBehavior].
 449#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
 450pub struct HitboxId(u64);
 451
 452impl HitboxId {
 453    /// Checks if the hitbox with this ID is currently hovered. Except when handling
 454    /// `ScrollWheelEvent`, this is typically what you want when determining whether to handle mouse
 455    /// events or paint hover styles.
 456    ///
 457    /// See [`Hitbox::is_hovered`] for details.
 458    pub fn is_hovered(self, window: &Window) -> bool {
 459        let hit_test = &window.mouse_hit_test;
 460        for id in hit_test.ids.iter().take(hit_test.hover_hitbox_count) {
 461            if self == *id {
 462                return true;
 463            }
 464        }
 465        return false;
 466    }
 467
 468    /// Checks if the hitbox with this ID contains the mouse and should handle scroll events.
 469    /// Typically this should only be used when handling `ScrollWheelEvent`, and otherwise
 470    /// `is_hovered` should be used. See the documentation of `Hitbox::is_hovered` for details about
 471    /// this distinction.
 472    pub fn should_handle_scroll(self, window: &Window) -> bool {
 473        window.mouse_hit_test.ids.contains(&self)
 474    }
 475
 476    fn next(mut self) -> HitboxId {
 477        HitboxId(self.0.wrapping_add(1))
 478    }
 479}
 480
 481/// A rectangular region that potentially blocks hitboxes inserted prior.
 482/// See [Window::insert_hitbox] for more details.
 483#[derive(Clone, Debug, Deref)]
 484pub struct Hitbox {
 485    /// A unique identifier for the hitbox.
 486    pub id: HitboxId,
 487    /// The bounds of the hitbox.
 488    #[deref]
 489    pub bounds: Bounds<Pixels>,
 490    /// The content mask when the hitbox was inserted.
 491    pub content_mask: ContentMask<Pixels>,
 492    /// Flags that specify hitbox behavior.
 493    pub behavior: HitboxBehavior,
 494}
 495
 496impl Hitbox {
 497    /// Checks if the hitbox is currently hovered. Except when handling `ScrollWheelEvent`, this is
 498    /// typically what you want when determining whether to handle mouse events or paint hover
 499    /// styles.
 500    ///
 501    /// This can return `false` even when the hitbox contains the mouse, if a hitbox in front of
 502    /// this sets `HitboxBehavior::BlockMouse` (`InteractiveElement::occlude`) or
 503    /// `HitboxBehavior::BlockMouseExceptScroll` (`InteractiveElement::block_mouse_except_scroll`).
 504    ///
 505    /// Handling of `ScrollWheelEvent` should typically use `should_handle_scroll` instead.
 506    /// Concretely, this is due to use-cases like overlays that cause the elements under to be
 507    /// non-interactive while still allowing scrolling. More abstractly, this is because
 508    /// `is_hovered` is about element interactions directly under the mouse - mouse moves, clicks,
 509    /// hover styling, etc. In contrast, scrolling is about finding the current outer scrollable
 510    /// container.
 511    pub fn is_hovered(&self, window: &Window) -> bool {
 512        self.id.is_hovered(window)
 513    }
 514
 515    /// Checks if the hitbox contains the mouse and should handle scroll events. Typically this
 516    /// should only be used when handling `ScrollWheelEvent`, and otherwise `is_hovered` should be
 517    /// used. See the documentation of `Hitbox::is_hovered` for details about this distinction.
 518    ///
 519    /// This can return `false` even when the hitbox contains the mouse, if a hitbox in front of
 520    /// this sets `HitboxBehavior::BlockMouse` (`InteractiveElement::occlude`).
 521    pub fn should_handle_scroll(&self, window: &Window) -> bool {
 522        self.id.should_handle_scroll(window)
 523    }
 524}
 525
 526/// How the hitbox affects mouse behavior.
 527#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 528pub enum HitboxBehavior {
 529    /// Normal hitbox mouse behavior, doesn't affect mouse handling for other hitboxes.
 530    #[default]
 531    Normal,
 532
 533    /// All hitboxes behind this hitbox will be ignored and so will have `hitbox.is_hovered() ==
 534    /// false` and `hitbox.should_handle_scroll() == false`. Typically for elements this causes
 535    /// skipping of all mouse events, hover styles, and tooltips. This flag is set by
 536    /// [`InteractiveElement::occlude`].
 537    ///
 538    /// For mouse handlers that check those hitboxes, this behaves the same as registering a
 539    /// bubble-phase handler for every mouse event type:
 540    ///
 541    /// ```
 542    /// window.on_mouse_event(move |_: &EveryMouseEventTypeHere, phase, window, cx| {
 543    ///     if phase == DispatchPhase::Capture && hitbox.is_hovered(window) {
 544    ///         cx.stop_propagation();
 545    ///     }
 546    /// }
 547    /// ```
 548    ///
 549    /// This has effects beyond event handling - any use of hitbox checking, such as hover
 550    /// styles and tooltops. These other behaviors are the main point of this mechanism. An
 551    /// alternative might be to not affect mouse event handling - but this would allow
 552    /// inconsistent UI where clicks and moves interact with elements that are not considered to
 553    /// be hovered.
 554    BlockMouse,
 555
 556    /// All hitboxes behind this hitbox will have `hitbox.is_hovered() == false`, even when
 557    /// `hitbox.should_handle_scroll() == true`. Typically for elements this causes all mouse
 558    /// interaction except scroll events to be ignored - see the documentation of
 559    /// [`Hitbox::is_hovered`] for details. This flag is set by
 560    /// [`InteractiveElement::block_mouse_except_scroll`].
 561    ///
 562    /// For mouse handlers that check those hitboxes, this behaves the same as registering a
 563    /// bubble-phase handler for every mouse event type **except** `ScrollWheelEvent`:
 564    ///
 565    /// ```
 566    /// window.on_mouse_event(move |_: &EveryMouseEventTypeExceptScroll, phase, window, _cx| {
 567    ///     if phase == DispatchPhase::Bubble && hitbox.should_handle_scroll(window) {
 568    ///         cx.stop_propagation();
 569    ///     }
 570    /// }
 571    /// ```
 572    ///
 573    /// See the documentation of [`Hitbox::is_hovered`] for details of why `ScrollWheelEvent` is
 574    /// handled differently than other mouse events. If also blocking these scroll events is
 575    /// desired, then a `cx.stop_propagation()` handler like the one above can be used.
 576    ///
 577    /// This has effects beyond event handling - this affects any use of `is_hovered`, such as
 578    /// hover styles and tooltops. These other behaviors are the main point of this mechanism.
 579    /// An alternative might be to not affect mouse event handling - but this would allow
 580    /// inconsistent UI where clicks and moves interact with elements that are not considered to
 581    /// be hovered.
 582    BlockMouseExceptScroll,
 583}
 584
 585/// An identifier for a tooltip.
 586#[derive(Copy, Clone, Debug, Default, Eq, PartialEq)]
 587pub struct TooltipId(usize);
 588
 589impl TooltipId {
 590    /// Checks if the tooltip is currently hovered.
 591    pub fn is_hovered(&self, window: &Window) -> bool {
 592        window
 593            .tooltip_bounds
 594            .as_ref()
 595            .map_or(false, |tooltip_bounds| {
 596                tooltip_bounds.id == *self
 597                    && tooltip_bounds.bounds.contains(&window.mouse_position())
 598            })
 599    }
 600}
 601
 602pub(crate) struct TooltipBounds {
 603    id: TooltipId,
 604    bounds: Bounds<Pixels>,
 605}
 606
 607#[derive(Clone)]
 608pub(crate) struct TooltipRequest {
 609    id: TooltipId,
 610    tooltip: AnyTooltip,
 611}
 612
 613pub(crate) struct DeferredDraw {
 614    current_view: EntityId,
 615    priority: usize,
 616    parent_node: DispatchNodeId,
 617    element_id_stack: SmallVec<[ElementId; 32]>,
 618    text_style_stack: Vec<TextStyleRefinement>,
 619    element: Option<AnyElement>,
 620    absolute_offset: Point<Pixels>,
 621    prepaint_range: Range<PrepaintStateIndex>,
 622    paint_range: Range<PaintIndex>,
 623}
 624
 625pub(crate) struct Frame {
 626    pub(crate) focus: Option<FocusId>,
 627    pub(crate) window_active: bool,
 628    pub(crate) element_states: FxHashMap<(GlobalElementId, TypeId), ElementStateBox>,
 629    accessed_element_states: Vec<(GlobalElementId, TypeId)>,
 630    pub(crate) mouse_listeners: Vec<Option<AnyMouseListener>>,
 631    pub(crate) dispatch_tree: DispatchTree,
 632    pub(crate) scene: Scene,
 633    pub(crate) hitboxes: Vec<Hitbox>,
 634    pub(crate) window_control_hitboxes: Vec<(WindowControlArea, Hitbox)>,
 635    pub(crate) deferred_draws: Vec<DeferredDraw>,
 636    pub(crate) input_handlers: Vec<Option<PlatformInputHandler>>,
 637    pub(crate) tooltip_requests: Vec<Option<TooltipRequest>>,
 638    pub(crate) cursor_styles: Vec<CursorStyleRequest>,
 639    #[cfg(any(test, feature = "test-support"))]
 640    pub(crate) debug_bounds: FxHashMap<String, Bounds<Pixels>>,
 641    #[cfg(any(feature = "inspector", debug_assertions))]
 642    pub(crate) next_inspector_instance_ids: FxHashMap<Rc<crate::InspectorElementPath>, usize>,
 643    #[cfg(any(feature = "inspector", debug_assertions))]
 644    pub(crate) inspector_hitboxes: FxHashMap<HitboxId, crate::InspectorElementId>,
 645}
 646
 647#[derive(Clone, Default)]
 648pub(crate) struct PrepaintStateIndex {
 649    hitboxes_index: usize,
 650    tooltips_index: usize,
 651    deferred_draws_index: usize,
 652    dispatch_tree_index: usize,
 653    accessed_element_states_index: usize,
 654    line_layout_index: LineLayoutIndex,
 655}
 656
 657#[derive(Clone, Default)]
 658pub(crate) struct PaintIndex {
 659    scene_index: usize,
 660    mouse_listeners_index: usize,
 661    input_handlers_index: usize,
 662    cursor_styles_index: usize,
 663    accessed_element_states_index: usize,
 664    line_layout_index: LineLayoutIndex,
 665}
 666
 667impl Frame {
 668    pub(crate) fn new(dispatch_tree: DispatchTree) -> Self {
 669        Frame {
 670            focus: None,
 671            window_active: false,
 672            element_states: FxHashMap::default(),
 673            accessed_element_states: Vec::new(),
 674            mouse_listeners: Vec::new(),
 675            dispatch_tree,
 676            scene: Scene::default(),
 677            hitboxes: Vec::new(),
 678            window_control_hitboxes: Vec::new(),
 679            deferred_draws: Vec::new(),
 680            input_handlers: Vec::new(),
 681            tooltip_requests: Vec::new(),
 682            cursor_styles: Vec::new(),
 683
 684            #[cfg(any(test, feature = "test-support"))]
 685            debug_bounds: FxHashMap::default(),
 686
 687            #[cfg(any(feature = "inspector", debug_assertions))]
 688            next_inspector_instance_ids: FxHashMap::default(),
 689
 690            #[cfg(any(feature = "inspector", debug_assertions))]
 691            inspector_hitboxes: FxHashMap::default(),
 692        }
 693    }
 694
 695    pub(crate) fn clear(&mut self) {
 696        self.element_states.clear();
 697        self.accessed_element_states.clear();
 698        self.mouse_listeners.clear();
 699        self.dispatch_tree.clear();
 700        self.scene.clear();
 701        self.input_handlers.clear();
 702        self.tooltip_requests.clear();
 703        self.cursor_styles.clear();
 704        self.hitboxes.clear();
 705        self.window_control_hitboxes.clear();
 706        self.deferred_draws.clear();
 707        self.focus = None;
 708
 709        #[cfg(any(feature = "inspector", debug_assertions))]
 710        {
 711            self.next_inspector_instance_ids.clear();
 712            self.inspector_hitboxes.clear();
 713        }
 714    }
 715
 716    pub(crate) fn cursor_style(&self, window: &Window) -> Option<CursorStyle> {
 717        self.cursor_styles
 718            .iter()
 719            .rev()
 720            .fold_while(None, |style, request| match request.hitbox_id {
 721                None => Done(Some(request.style)),
 722                Some(hitbox_id) => Continue(
 723                    style.or_else(|| hitbox_id.is_hovered(window).then_some(request.style)),
 724                ),
 725            })
 726            .into_inner()
 727    }
 728
 729    pub(crate) fn hit_test(&self, position: Point<Pixels>) -> HitTest {
 730        let mut set_hover_hitbox_count = false;
 731        let mut hit_test = HitTest::default();
 732        for hitbox in self.hitboxes.iter().rev() {
 733            let bounds = hitbox.bounds.intersect(&hitbox.content_mask.bounds);
 734            if bounds.contains(&position) {
 735                hit_test.ids.push(hitbox.id);
 736                if !set_hover_hitbox_count
 737                    && hitbox.behavior == HitboxBehavior::BlockMouseExceptScroll
 738                {
 739                    hit_test.hover_hitbox_count = hit_test.ids.len();
 740                    set_hover_hitbox_count = true;
 741                }
 742                if hitbox.behavior == HitboxBehavior::BlockMouse {
 743                    break;
 744                }
 745            }
 746        }
 747        if !set_hover_hitbox_count {
 748            hit_test.hover_hitbox_count = hit_test.ids.len();
 749        }
 750        hit_test
 751    }
 752
 753    pub(crate) fn focus_path(&self) -> SmallVec<[FocusId; 8]> {
 754        self.focus
 755            .map(|focus_id| self.dispatch_tree.focus_path(focus_id))
 756            .unwrap_or_default()
 757    }
 758
 759    pub(crate) fn finish(&mut self, prev_frame: &mut Self) {
 760        for element_state_key in &self.accessed_element_states {
 761            if let Some((element_state_key, element_state)) =
 762                prev_frame.element_states.remove_entry(element_state_key)
 763            {
 764                self.element_states.insert(element_state_key, element_state);
 765            }
 766        }
 767
 768        self.scene.finish();
 769    }
 770}
 771
 772/// Holds the state for a specific window.
 773pub struct Window {
 774    pub(crate) handle: AnyWindowHandle,
 775    pub(crate) invalidator: WindowInvalidator,
 776    pub(crate) removed: bool,
 777    pub(crate) platform_window: Box<dyn PlatformWindow>,
 778    display_id: Option<DisplayId>,
 779    sprite_atlas: Arc<dyn PlatformAtlas>,
 780    text_system: Arc<WindowTextSystem>,
 781    rem_size: Pixels,
 782    /// The stack of override values for the window's rem size.
 783    ///
 784    /// This is used by `with_rem_size` to allow rendering an element tree with
 785    /// a given rem size.
 786    rem_size_override_stack: SmallVec<[Pixels; 8]>,
 787    pub(crate) viewport_size: Size<Pixels>,
 788    layout_engine: Option<TaffyLayoutEngine>,
 789    pub(crate) root: Option<AnyView>,
 790    pub(crate) element_id_stack: SmallVec<[ElementId; 32]>,
 791    pub(crate) text_style_stack: Vec<TextStyleRefinement>,
 792    pub(crate) rendered_entity_stack: Vec<EntityId>,
 793    pub(crate) element_offset_stack: Vec<Point<Pixels>>,
 794    pub(crate) element_opacity: Option<f32>,
 795    pub(crate) content_mask_stack: Vec<ContentMask<Pixels>>,
 796    pub(crate) requested_autoscroll: Option<Bounds<Pixels>>,
 797    pub(crate) image_cache_stack: Vec<AnyImageCache>,
 798    pub(crate) rendered_frame: Frame,
 799    pub(crate) next_frame: Frame,
 800    next_hitbox_id: HitboxId,
 801    pub(crate) next_tooltip_id: TooltipId,
 802    pub(crate) tooltip_bounds: Option<TooltipBounds>,
 803    next_frame_callbacks: Rc<RefCell<Vec<FrameCallback>>>,
 804    pub(crate) dirty_views: FxHashSet<EntityId>,
 805    focus_listeners: SubscriberSet<(), AnyWindowFocusListener>,
 806    pub(crate) focus_lost_listeners: SubscriberSet<(), AnyObserver>,
 807    default_prevented: bool,
 808    mouse_position: Point<Pixels>,
 809    mouse_hit_test: HitTest,
 810    modifiers: Modifiers,
 811    capslock: Capslock,
 812    scale_factor: f32,
 813    pub(crate) bounds_observers: SubscriberSet<(), AnyObserver>,
 814    appearance: WindowAppearance,
 815    pub(crate) appearance_observers: SubscriberSet<(), AnyObserver>,
 816    active: Rc<Cell<bool>>,
 817    hovered: Rc<Cell<bool>>,
 818    pub(crate) needs_present: Rc<Cell<bool>>,
 819    pub(crate) last_input_timestamp: Rc<Cell<Instant>>,
 820    pub(crate) refreshing: bool,
 821    pub(crate) activation_observers: SubscriberSet<(), AnyObserver>,
 822    pub(crate) focus: Option<FocusId>,
 823    focus_enabled: bool,
 824    pending_input: Option<PendingInput>,
 825    pending_modifier: ModifierState,
 826    pub(crate) pending_input_observers: SubscriberSet<(), AnyObserver>,
 827    prompt: Option<RenderablePromptHandle>,
 828    pub(crate) client_inset: Option<Pixels>,
 829    #[cfg(any(feature = "inspector", debug_assertions))]
 830    inspector: Option<Entity<Inspector>>,
 831}
 832
 833#[derive(Clone, Debug, Default)]
 834struct ModifierState {
 835    modifiers: Modifiers,
 836    saw_keystroke: bool,
 837}
 838
 839#[derive(Clone, Copy, Debug, Eq, PartialEq)]
 840pub(crate) enum DrawPhase {
 841    None,
 842    Prepaint,
 843    Paint,
 844    Focus,
 845}
 846
 847#[derive(Default, Debug)]
 848struct PendingInput {
 849    keystrokes: SmallVec<[Keystroke; 1]>,
 850    focus: Option<FocusId>,
 851    timer: Option<Task<()>>,
 852}
 853
 854pub(crate) struct ElementStateBox {
 855    pub(crate) inner: Box<dyn Any>,
 856    #[cfg(debug_assertions)]
 857    pub(crate) type_name: &'static str,
 858}
 859
 860fn default_bounds(display_id: Option<DisplayId>, cx: &mut App) -> Bounds<Pixels> {
 861    const DEFAULT_WINDOW_OFFSET: Point<Pixels> = point(px(0.), px(35.));
 862
 863    // TODO, BUG: if you open a window with the currently active window
 864    // on the stack, this will erroneously select the 'unwrap_or_else'
 865    // code path
 866    cx.active_window()
 867        .and_then(|w| w.update(cx, |_, window, _| window.bounds()).ok())
 868        .map(|mut bounds| {
 869            bounds.origin += DEFAULT_WINDOW_OFFSET;
 870            bounds
 871        })
 872        .unwrap_or_else(|| {
 873            let display = display_id
 874                .map(|id| cx.find_display(id))
 875                .unwrap_or_else(|| cx.primary_display());
 876
 877            display
 878                .map(|display| display.default_bounds())
 879                .unwrap_or_else(|| Bounds::new(point(px(0.), px(0.)), DEFAULT_WINDOW_SIZE))
 880        })
 881}
 882
 883impl Window {
 884    pub(crate) fn new(
 885        handle: AnyWindowHandle,
 886        options: WindowOptions,
 887        cx: &mut App,
 888    ) -> Result<Self> {
 889        let WindowOptions {
 890            window_bounds,
 891            titlebar,
 892            focus,
 893            show,
 894            kind,
 895            is_movable,
 896            display_id,
 897            window_background,
 898            app_id,
 899            window_min_size,
 900            window_decorations,
 901        } = options;
 902
 903        let bounds = window_bounds
 904            .map(|bounds| bounds.get_bounds())
 905            .unwrap_or_else(|| default_bounds(display_id, cx));
 906        let mut platform_window = cx.platform.open_window(
 907            handle,
 908            WindowParams {
 909                bounds,
 910                titlebar,
 911                kind,
 912                is_movable,
 913                focus,
 914                show,
 915                display_id,
 916                window_min_size,
 917            },
 918        )?;
 919        let display_id = platform_window.display().map(|display| display.id());
 920        let sprite_atlas = platform_window.sprite_atlas();
 921        let mouse_position = platform_window.mouse_position();
 922        let modifiers = platform_window.modifiers();
 923        let capslock = platform_window.capslock();
 924        let content_size = platform_window.content_size();
 925        let scale_factor = platform_window.scale_factor();
 926        let appearance = platform_window.appearance();
 927        let text_system = Arc::new(WindowTextSystem::new(cx.text_system().clone()));
 928        let invalidator = WindowInvalidator::new();
 929        let active = Rc::new(Cell::new(platform_window.is_active()));
 930        let hovered = Rc::new(Cell::new(platform_window.is_hovered()));
 931        let needs_present = Rc::new(Cell::new(false));
 932        let next_frame_callbacks: Rc<RefCell<Vec<FrameCallback>>> = Default::default();
 933        let last_input_timestamp = Rc::new(Cell::new(Instant::now()));
 934
 935        platform_window
 936            .request_decorations(window_decorations.unwrap_or(WindowDecorations::Server));
 937        platform_window.set_background_appearance(window_background);
 938
 939        if let Some(ref window_open_state) = window_bounds {
 940            match window_open_state {
 941                WindowBounds::Fullscreen(_) => platform_window.toggle_fullscreen(),
 942                WindowBounds::Maximized(_) => platform_window.zoom(),
 943                WindowBounds::Windowed(_) => {}
 944            }
 945        }
 946
 947        platform_window.on_close(Box::new({
 948            let mut cx = cx.to_async();
 949            move || {
 950                let _ = handle.update(&mut cx, |_, window, _| window.remove_window());
 951            }
 952        }));
 953        platform_window.on_request_frame(Box::new({
 954            let mut cx = cx.to_async();
 955            let invalidator = invalidator.clone();
 956            let active = active.clone();
 957            let needs_present = needs_present.clone();
 958            let next_frame_callbacks = next_frame_callbacks.clone();
 959            let last_input_timestamp = last_input_timestamp.clone();
 960            move |request_frame_options| {
 961                let next_frame_callbacks = next_frame_callbacks.take();
 962                if !next_frame_callbacks.is_empty() {
 963                    handle
 964                        .update(&mut cx, |_, window, cx| {
 965                            for callback in next_frame_callbacks {
 966                                callback(window, cx);
 967                            }
 968                        })
 969                        .log_err();
 970                }
 971
 972                // Keep presenting the current scene for 1 extra second since the
 973                // last input to prevent the display from underclocking the refresh rate.
 974                let needs_present = request_frame_options.require_presentation
 975                    || needs_present.get()
 976                    || (active.get()
 977                        && last_input_timestamp.get().elapsed() < Duration::from_secs(1));
 978
 979                if invalidator.is_dirty() {
 980                    measure("frame duration", || {
 981                        handle
 982                            .update(&mut cx, |_, window, cx| {
 983                                let arena_clear_needed = window.draw(cx);
 984                                window.present();
 985                                // drop the arena elements after present to reduce latency
 986                                arena_clear_needed.clear();
 987                            })
 988                            .log_err();
 989                    })
 990                } else if needs_present {
 991                    handle
 992                        .update(&mut cx, |_, window, _| window.present())
 993                        .log_err();
 994                }
 995
 996                handle
 997                    .update(&mut cx, |_, window, _| {
 998                        window.complete_frame();
 999                    })
1000                    .log_err();
1001            }
1002        }));
1003        platform_window.on_resize(Box::new({
1004            let mut cx = cx.to_async();
1005            move |_, _| {
1006                handle
1007                    .update(&mut cx, |_, window, cx| window.bounds_changed(cx))
1008                    .log_err();
1009            }
1010        }));
1011        platform_window.on_moved(Box::new({
1012            let mut cx = cx.to_async();
1013            move || {
1014                handle
1015                    .update(&mut cx, |_, window, cx| window.bounds_changed(cx))
1016                    .log_err();
1017            }
1018        }));
1019        platform_window.on_appearance_changed(Box::new({
1020            let mut cx = cx.to_async();
1021            move || {
1022                handle
1023                    .update(&mut cx, |_, window, cx| window.appearance_changed(cx))
1024                    .log_err();
1025            }
1026        }));
1027        platform_window.on_active_status_change(Box::new({
1028            let mut cx = cx.to_async();
1029            move |active| {
1030                handle
1031                    .update(&mut cx, |_, window, cx| {
1032                        window.active.set(active);
1033                        window.modifiers = window.platform_window.modifiers();
1034                        window.capslock = window.platform_window.capslock();
1035                        window
1036                            .activation_observers
1037                            .clone()
1038                            .retain(&(), |callback| callback(window, cx));
1039                        window.refresh();
1040                    })
1041                    .log_err();
1042            }
1043        }));
1044        platform_window.on_hover_status_change(Box::new({
1045            let mut cx = cx.to_async();
1046            move |active| {
1047                handle
1048                    .update(&mut cx, |_, window, _| {
1049                        window.hovered.set(active);
1050                        window.refresh();
1051                    })
1052                    .log_err();
1053            }
1054        }));
1055        platform_window.on_input({
1056            let mut cx = cx.to_async();
1057            Box::new(move |event| {
1058                handle
1059                    .update(&mut cx, |_, window, cx| window.dispatch_event(event, cx))
1060                    .log_err()
1061                    .unwrap_or(DispatchEventResult::default())
1062            })
1063        });
1064        platform_window.on_hit_test_window_control({
1065            let mut cx = cx.to_async();
1066            Box::new(move || {
1067                handle
1068                    .update(&mut cx, |_, window, _cx| {
1069                        for (area, hitbox) in &window.rendered_frame.window_control_hitboxes {
1070                            if window.mouse_hit_test.ids.contains(&hitbox.id) {
1071                                return Some(*area);
1072                            }
1073                        }
1074                        None
1075                    })
1076                    .log_err()
1077                    .unwrap_or(None)
1078            })
1079        });
1080
1081        if let Some(app_id) = app_id {
1082            platform_window.set_app_id(&app_id);
1083        }
1084
1085        platform_window.map_window().unwrap();
1086
1087        Ok(Window {
1088            handle,
1089            invalidator,
1090            removed: false,
1091            platform_window,
1092            display_id,
1093            sprite_atlas,
1094            text_system,
1095            rem_size: px(16.),
1096            rem_size_override_stack: SmallVec::new(),
1097            viewport_size: content_size,
1098            layout_engine: Some(TaffyLayoutEngine::new()),
1099            root: None,
1100            element_id_stack: SmallVec::default(),
1101            text_style_stack: Vec::new(),
1102            rendered_entity_stack: Vec::new(),
1103            element_offset_stack: Vec::new(),
1104            content_mask_stack: Vec::new(),
1105            element_opacity: None,
1106            requested_autoscroll: None,
1107            rendered_frame: Frame::new(DispatchTree::new(cx.keymap.clone(), cx.actions.clone())),
1108            next_frame: Frame::new(DispatchTree::new(cx.keymap.clone(), cx.actions.clone())),
1109            next_frame_callbacks,
1110            next_hitbox_id: HitboxId(0),
1111            next_tooltip_id: TooltipId::default(),
1112            tooltip_bounds: None,
1113            dirty_views: FxHashSet::default(),
1114            focus_listeners: SubscriberSet::new(),
1115            focus_lost_listeners: SubscriberSet::new(),
1116            default_prevented: true,
1117            mouse_position,
1118            mouse_hit_test: HitTest::default(),
1119            modifiers,
1120            capslock,
1121            scale_factor,
1122            bounds_observers: SubscriberSet::new(),
1123            appearance,
1124            appearance_observers: SubscriberSet::new(),
1125            active,
1126            hovered,
1127            needs_present,
1128            last_input_timestamp,
1129            refreshing: false,
1130            activation_observers: SubscriberSet::new(),
1131            focus: None,
1132            focus_enabled: true,
1133            pending_input: None,
1134            pending_modifier: ModifierState::default(),
1135            pending_input_observers: SubscriberSet::new(),
1136            prompt: None,
1137            client_inset: None,
1138            image_cache_stack: Vec::new(),
1139            #[cfg(any(feature = "inspector", debug_assertions))]
1140            inspector: None,
1141        })
1142    }
1143
1144    pub(crate) fn new_focus_listener(
1145        &self,
1146        value: AnyWindowFocusListener,
1147    ) -> (Subscription, impl FnOnce() + use<>) {
1148        self.focus_listeners.insert((), value)
1149    }
1150}
1151
1152#[derive(Clone, Debug, Default, PartialEq, Eq)]
1153pub(crate) struct DispatchEventResult {
1154    pub propagate: bool,
1155    pub default_prevented: bool,
1156}
1157
1158/// Indicates which region of the window is visible. Content falling outside of this mask will not be
1159/// rendered. Currently, only rectangular content masks are supported, but we give the mask its own type
1160/// to leave room to support more complex shapes in the future.
1161#[derive(Clone, Debug, Default, PartialEq, Eq)]
1162#[repr(C)]
1163pub struct ContentMask<P: Clone + Debug + Default + PartialEq> {
1164    /// The bounds
1165    pub bounds: Bounds<P>,
1166}
1167
1168impl ContentMask<Pixels> {
1169    /// Scale the content mask's pixel units by the given scaling factor.
1170    pub fn scale(&self, factor: f32) -> ContentMask<ScaledPixels> {
1171        ContentMask {
1172            bounds: self.bounds.scale(factor),
1173        }
1174    }
1175
1176    /// Intersect the content mask with the given content mask.
1177    pub fn intersect(&self, other: &Self) -> Self {
1178        let bounds = self.bounds.intersect(&other.bounds);
1179        ContentMask { bounds }
1180    }
1181}
1182
1183impl Window {
1184    fn mark_view_dirty(&mut self, view_id: EntityId) {
1185        // Mark ancestor views as dirty. If already in the `dirty_views` set, then all its ancestors
1186        // should already be dirty.
1187        for view_id in self
1188            .rendered_frame
1189            .dispatch_tree
1190            .view_path(view_id)
1191            .into_iter()
1192            .rev()
1193        {
1194            if !self.dirty_views.insert(view_id) {
1195                break;
1196            }
1197        }
1198    }
1199
1200    /// Registers a callback to be invoked when the window appearance changes.
1201    pub fn observe_window_appearance(
1202        &self,
1203        mut callback: impl FnMut(&mut Window, &mut App) + 'static,
1204    ) -> Subscription {
1205        let (subscription, activate) = self.appearance_observers.insert(
1206            (),
1207            Box::new(move |window, cx| {
1208                callback(window, cx);
1209                true
1210            }),
1211        );
1212        activate();
1213        subscription
1214    }
1215
1216    /// Replaces the root entity of the window with a new one.
1217    pub fn replace_root<E>(
1218        &mut self,
1219        cx: &mut App,
1220        build_view: impl FnOnce(&mut Window, &mut Context<E>) -> E,
1221    ) -> Entity<E>
1222    where
1223        E: 'static + Render,
1224    {
1225        let view = cx.new(|cx| build_view(self, cx));
1226        self.root = Some(view.clone().into());
1227        self.refresh();
1228        view
1229    }
1230
1231    /// Returns the root entity of the window, if it has one.
1232    pub fn root<E>(&self) -> Option<Option<Entity<E>>>
1233    where
1234        E: 'static + Render,
1235    {
1236        self.root
1237            .as_ref()
1238            .map(|view| view.clone().downcast::<E>().ok())
1239    }
1240
1241    /// Obtain a handle to the window that belongs to this context.
1242    pub fn window_handle(&self) -> AnyWindowHandle {
1243        self.handle
1244    }
1245
1246    /// Mark the window as dirty, scheduling it to be redrawn on the next frame.
1247    pub fn refresh(&mut self) {
1248        if self.invalidator.not_drawing() {
1249            self.refreshing = true;
1250            self.invalidator.set_dirty(true);
1251        }
1252    }
1253
1254    /// Close this window.
1255    pub fn remove_window(&mut self) {
1256        self.removed = true;
1257    }
1258
1259    /// Obtain the currently focused [`FocusHandle`]. If no elements are focused, returns `None`.
1260    pub fn focused(&self, cx: &App) -> Option<FocusHandle> {
1261        self.focus
1262            .and_then(|id| FocusHandle::for_id(id, &cx.focus_handles))
1263    }
1264
1265    /// Move focus to the element associated with the given [`FocusHandle`].
1266    pub fn focus(&mut self, handle: &FocusHandle) {
1267        if !self.focus_enabled || self.focus == Some(handle.id) {
1268            return;
1269        }
1270
1271        self.focus = Some(handle.id);
1272        self.clear_pending_keystrokes();
1273        self.refresh();
1274    }
1275
1276    /// Remove focus from all elements within this context's window.
1277    pub fn blur(&mut self) {
1278        if !self.focus_enabled {
1279            return;
1280        }
1281
1282        self.focus = None;
1283        self.refresh();
1284    }
1285
1286    /// Blur the window and don't allow anything in it to be focused again.
1287    pub fn disable_focus(&mut self) {
1288        self.blur();
1289        self.focus_enabled = false;
1290    }
1291
1292    /// Accessor for the text system.
1293    pub fn text_system(&self) -> &Arc<WindowTextSystem> {
1294        &self.text_system
1295    }
1296
1297    /// The current text style. Which is composed of all the style refinements provided to `with_text_style`.
1298    pub fn text_style(&self) -> TextStyle {
1299        let mut style = TextStyle::default();
1300        for refinement in &self.text_style_stack {
1301            style.refine(refinement);
1302        }
1303        style
1304    }
1305
1306    /// Check if the platform window is maximized
1307    /// On some platforms (namely Windows) this is different than the bounds being the size of the display
1308    pub fn is_maximized(&self) -> bool {
1309        self.platform_window.is_maximized()
1310    }
1311
1312    /// request a certain window decoration (Wayland)
1313    pub fn request_decorations(&self, decorations: WindowDecorations) {
1314        self.platform_window.request_decorations(decorations);
1315    }
1316
1317    /// Start a window resize operation (Wayland)
1318    pub fn start_window_resize(&self, edge: ResizeEdge) {
1319        self.platform_window.start_window_resize(edge);
1320    }
1321
1322    /// Return the `WindowBounds` to indicate that how a window should be opened
1323    /// after it has been closed
1324    pub fn window_bounds(&self) -> WindowBounds {
1325        self.platform_window.window_bounds()
1326    }
1327
1328    /// Return the `WindowBounds` excluding insets (Wayland and X11)
1329    pub fn inner_window_bounds(&self) -> WindowBounds {
1330        self.platform_window.inner_window_bounds()
1331    }
1332
1333    /// Dispatch the given action on the currently focused element.
1334    pub fn dispatch_action(&mut self, action: Box<dyn Action>, cx: &mut App) {
1335        let focus_id = self.focused(cx).map(|handle| handle.id);
1336
1337        let window = self.handle;
1338        cx.defer(move |cx| {
1339            window
1340                .update(cx, |_, window, cx| {
1341                    let node_id = window.focus_node_id_in_rendered_frame(focus_id);
1342                    window.dispatch_action_on_node(node_id, action.as_ref(), cx);
1343                })
1344                .log_err();
1345        })
1346    }
1347
1348    pub(crate) fn dispatch_keystroke_observers(
1349        &mut self,
1350        event: &dyn Any,
1351        action: Option<Box<dyn Action>>,
1352        context_stack: Vec<KeyContext>,
1353        cx: &mut App,
1354    ) {
1355        let Some(key_down_event) = event.downcast_ref::<KeyDownEvent>() else {
1356            return;
1357        };
1358
1359        cx.keystroke_observers.clone().retain(&(), move |callback| {
1360            (callback)(
1361                &KeystrokeEvent {
1362                    keystroke: key_down_event.keystroke.clone(),
1363                    action: action.as_ref().map(|action| action.boxed_clone()),
1364                    context_stack: context_stack.clone(),
1365                },
1366                self,
1367                cx,
1368            )
1369        });
1370    }
1371
1372    pub(crate) fn dispatch_keystroke_interceptors(
1373        &mut self,
1374        event: &dyn Any,
1375        context_stack: Vec<KeyContext>,
1376        cx: &mut App,
1377    ) {
1378        let Some(key_down_event) = event.downcast_ref::<KeyDownEvent>() else {
1379            return;
1380        };
1381
1382        cx.keystroke_interceptors
1383            .clone()
1384            .retain(&(), move |callback| {
1385                (callback)(
1386                    &KeystrokeEvent {
1387                        keystroke: key_down_event.keystroke.clone(),
1388                        action: None,
1389                        context_stack: context_stack.clone(),
1390                    },
1391                    self,
1392                    cx,
1393                )
1394            });
1395    }
1396
1397    /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
1398    /// that are currently on the stack to be returned to the app.
1399    pub fn defer(&self, cx: &mut App, f: impl FnOnce(&mut Window, &mut App) + 'static) {
1400        let handle = self.handle;
1401        cx.defer(move |cx| {
1402            handle.update(cx, |_, window, cx| f(window, cx)).ok();
1403        });
1404    }
1405
1406    /// Subscribe to events emitted by a entity.
1407    /// The entity to which you're subscribing must implement the [`EventEmitter`] trait.
1408    /// The callback will be invoked a handle to the emitting entity, the event, and a window context for the current window.
1409    pub fn observe<T: 'static>(
1410        &mut self,
1411        observed: &Entity<T>,
1412        cx: &mut App,
1413        mut on_notify: impl FnMut(Entity<T>, &mut Window, &mut App) + 'static,
1414    ) -> Subscription {
1415        let entity_id = observed.entity_id();
1416        let observed = observed.downgrade();
1417        let window_handle = self.handle;
1418        cx.new_observer(
1419            entity_id,
1420            Box::new(move |cx| {
1421                window_handle
1422                    .update(cx, |_, window, cx| {
1423                        if let Some(handle) = observed.upgrade() {
1424                            on_notify(handle, window, cx);
1425                            true
1426                        } else {
1427                            false
1428                        }
1429                    })
1430                    .unwrap_or(false)
1431            }),
1432        )
1433    }
1434
1435    /// Subscribe to events emitted by a entity.
1436    /// The entity to which you're subscribing must implement the [`EventEmitter`] trait.
1437    /// The callback will be invoked a handle to the emitting entity, the event, and a window context for the current window.
1438    pub fn subscribe<Emitter, Evt>(
1439        &mut self,
1440        entity: &Entity<Emitter>,
1441        cx: &mut App,
1442        mut on_event: impl FnMut(Entity<Emitter>, &Evt, &mut Window, &mut App) + 'static,
1443    ) -> Subscription
1444    where
1445        Emitter: EventEmitter<Evt>,
1446        Evt: 'static,
1447    {
1448        let entity_id = entity.entity_id();
1449        let handle = entity.downgrade();
1450        let window_handle = self.handle;
1451        cx.new_subscription(
1452            entity_id,
1453            (
1454                TypeId::of::<Evt>(),
1455                Box::new(move |event, cx| {
1456                    window_handle
1457                        .update(cx, |_, window, cx| {
1458                            if let Some(entity) = handle.upgrade() {
1459                                let event = event.downcast_ref().expect("invalid event type");
1460                                on_event(entity, event, window, cx);
1461                                true
1462                            } else {
1463                                false
1464                            }
1465                        })
1466                        .unwrap_or(false)
1467                }),
1468            ),
1469        )
1470    }
1471
1472    /// Register a callback to be invoked when the given `Entity` is released.
1473    pub fn observe_release<T>(
1474        &self,
1475        entity: &Entity<T>,
1476        cx: &mut App,
1477        mut on_release: impl FnOnce(&mut T, &mut Window, &mut App) + 'static,
1478    ) -> Subscription
1479    where
1480        T: 'static,
1481    {
1482        let entity_id = entity.entity_id();
1483        let window_handle = self.handle;
1484        let (subscription, activate) = cx.release_listeners.insert(
1485            entity_id,
1486            Box::new(move |entity, cx| {
1487                let entity = entity.downcast_mut().expect("invalid entity type");
1488                let _ = window_handle.update(cx, |_, window, cx| on_release(entity, window, cx));
1489            }),
1490        );
1491        activate();
1492        subscription
1493    }
1494
1495    /// Creates an [`AsyncWindowContext`], which has a static lifetime and can be held across
1496    /// await points in async code.
1497    pub fn to_async(&self, cx: &App) -> AsyncWindowContext {
1498        AsyncWindowContext::new_context(cx.to_async(), self.handle)
1499    }
1500
1501    /// Schedule the given closure to be run directly after the current frame is rendered.
1502    pub fn on_next_frame(&self, callback: impl FnOnce(&mut Window, &mut App) + 'static) {
1503        RefCell::borrow_mut(&self.next_frame_callbacks).push(Box::new(callback));
1504    }
1505
1506    /// Schedule a frame to be drawn on the next animation frame.
1507    ///
1508    /// This is useful for elements that need to animate continuously, such as a video player or an animated GIF.
1509    /// It will cause the window to redraw on the next frame, even if no other changes have occurred.
1510    ///
1511    /// If called from within a view, it will notify that view on the next frame. Otherwise, it will refresh the entire window.
1512    pub fn request_animation_frame(&self) {
1513        let entity = self.current_view();
1514        self.on_next_frame(move |_, cx| cx.notify(entity));
1515    }
1516
1517    /// Spawn the future returned by the given closure on the application thread pool.
1518    /// The closure is provided a handle to the current window and an `AsyncWindowContext` for
1519    /// use within your future.
1520    #[track_caller]
1521    pub fn spawn<AsyncFn, R>(&self, cx: &App, f: AsyncFn) -> Task<R>
1522    where
1523        R: 'static,
1524        AsyncFn: AsyncFnOnce(&mut AsyncWindowContext) -> R + 'static,
1525    {
1526        let handle = self.handle;
1527        cx.spawn(async move |app| {
1528            let mut async_window_cx = AsyncWindowContext::new_context(app.clone(), handle);
1529            f(&mut async_window_cx).await
1530        })
1531    }
1532
1533    fn bounds_changed(&mut self, cx: &mut App) {
1534        self.scale_factor = self.platform_window.scale_factor();
1535        self.viewport_size = self.platform_window.content_size();
1536        self.display_id = self.platform_window.display().map(|display| display.id());
1537
1538        self.refresh();
1539
1540        self.bounds_observers
1541            .clone()
1542            .retain(&(), |callback| callback(self, cx));
1543    }
1544
1545    /// Returns the bounds of the current window in the global coordinate space, which could span across multiple displays.
1546    pub fn bounds(&self) -> Bounds<Pixels> {
1547        self.platform_window.bounds()
1548    }
1549
1550    /// Set the content size of the window.
1551    pub fn resize(&mut self, size: Size<Pixels>) {
1552        self.platform_window.resize(size);
1553    }
1554
1555    /// Returns whether or not the window is currently fullscreen
1556    pub fn is_fullscreen(&self) -> bool {
1557        self.platform_window.is_fullscreen()
1558    }
1559
1560    pub(crate) fn appearance_changed(&mut self, cx: &mut App) {
1561        self.appearance = self.platform_window.appearance();
1562
1563        self.appearance_observers
1564            .clone()
1565            .retain(&(), |callback| callback(self, cx));
1566    }
1567
1568    /// Returns the appearance of the current window.
1569    pub fn appearance(&self) -> WindowAppearance {
1570        self.appearance
1571    }
1572
1573    /// Returns the size of the drawable area within the window.
1574    pub fn viewport_size(&self) -> Size<Pixels> {
1575        self.viewport_size
1576    }
1577
1578    /// Returns whether this window is focused by the operating system (receiving key events).
1579    pub fn is_window_active(&self) -> bool {
1580        self.active.get()
1581    }
1582
1583    /// Returns whether this window is considered to be the window
1584    /// that currently owns the mouse cursor.
1585    /// On mac, this is equivalent to `is_window_active`.
1586    pub fn is_window_hovered(&self) -> bool {
1587        if cfg!(any(
1588            target_os = "windows",
1589            target_os = "linux",
1590            target_os = "freebsd"
1591        )) {
1592            self.hovered.get()
1593        } else {
1594            self.is_window_active()
1595        }
1596    }
1597
1598    /// Toggle zoom on the window.
1599    pub fn zoom_window(&self) {
1600        self.platform_window.zoom();
1601    }
1602
1603    /// Opens the native title bar context menu, useful when implementing client side decorations (Wayland and X11)
1604    pub fn show_window_menu(&self, position: Point<Pixels>) {
1605        self.platform_window.show_window_menu(position)
1606    }
1607
1608    /// Tells the compositor to take control of window movement (Wayland and X11)
1609    ///
1610    /// Events may not be received during a move operation.
1611    pub fn start_window_move(&self) {
1612        self.platform_window.start_window_move()
1613    }
1614
1615    /// When using client side decorations, set this to the width of the invisible decorations (Wayland and X11)
1616    pub fn set_client_inset(&mut self, inset: Pixels) {
1617        self.client_inset = Some(inset);
1618        self.platform_window.set_client_inset(inset);
1619    }
1620
1621    /// Returns the client_inset value by [`Self::set_client_inset`].
1622    pub fn client_inset(&self) -> Option<Pixels> {
1623        self.client_inset
1624    }
1625
1626    /// Returns whether the title bar window controls need to be rendered by the application (Wayland and X11)
1627    pub fn window_decorations(&self) -> Decorations {
1628        self.platform_window.window_decorations()
1629    }
1630
1631    /// Returns which window controls are currently visible (Wayland)
1632    pub fn window_controls(&self) -> WindowControls {
1633        self.platform_window.window_controls()
1634    }
1635
1636    /// Updates the window's title at the platform level.
1637    pub fn set_window_title(&mut self, title: &str) {
1638        self.platform_window.set_title(title);
1639    }
1640
1641    /// Sets the application identifier.
1642    pub fn set_app_id(&mut self, app_id: &str) {
1643        self.platform_window.set_app_id(app_id);
1644    }
1645
1646    /// Sets the window background appearance.
1647    pub fn set_background_appearance(&self, background_appearance: WindowBackgroundAppearance) {
1648        self.platform_window
1649            .set_background_appearance(background_appearance);
1650    }
1651
1652    /// Mark the window as dirty at the platform level.
1653    pub fn set_window_edited(&mut self, edited: bool) {
1654        self.platform_window.set_edited(edited);
1655    }
1656
1657    /// Determine the display on which the window is visible.
1658    pub fn display(&self, cx: &App) -> Option<Rc<dyn PlatformDisplay>> {
1659        cx.platform
1660            .displays()
1661            .into_iter()
1662            .find(|display| Some(display.id()) == self.display_id)
1663    }
1664
1665    /// Show the platform character palette.
1666    pub fn show_character_palette(&self) {
1667        self.platform_window.show_character_palette();
1668    }
1669
1670    /// The scale factor of the display associated with the window. For example, it could
1671    /// return 2.0 for a "retina" display, indicating that each logical pixel should actually
1672    /// be rendered as two pixels on screen.
1673    pub fn scale_factor(&self) -> f32 {
1674        self.scale_factor
1675    }
1676
1677    /// The size of an em for the base font of the application. Adjusting this value allows the
1678    /// UI to scale, just like zooming a web page.
1679    pub fn rem_size(&self) -> Pixels {
1680        self.rem_size_override_stack
1681            .last()
1682            .copied()
1683            .unwrap_or(self.rem_size)
1684    }
1685
1686    /// Sets the size of an em for the base font of the application. Adjusting this value allows the
1687    /// UI to scale, just like zooming a web page.
1688    pub fn set_rem_size(&mut self, rem_size: impl Into<Pixels>) {
1689        self.rem_size = rem_size.into();
1690    }
1691
1692    /// Acquire a globally unique identifier for the given ElementId.
1693    /// Only valid for the duration of the provided closure.
1694    pub fn with_global_id<R>(
1695        &mut self,
1696        element_id: ElementId,
1697        f: impl FnOnce(&GlobalElementId, &mut Self) -> R,
1698    ) -> R {
1699        self.element_id_stack.push(element_id);
1700        let global_id = GlobalElementId(self.element_id_stack.clone());
1701        let result = f(&global_id, self);
1702        self.element_id_stack.pop();
1703        result
1704    }
1705
1706    /// Executes the provided function with the specified rem size.
1707    ///
1708    /// This method must only be called as part of element drawing.
1709    pub fn with_rem_size<F, R>(&mut self, rem_size: Option<impl Into<Pixels>>, f: F) -> R
1710    where
1711        F: FnOnce(&mut Self) -> R,
1712    {
1713        self.invalidator.debug_assert_paint_or_prepaint();
1714
1715        if let Some(rem_size) = rem_size {
1716            self.rem_size_override_stack.push(rem_size.into());
1717            let result = f(self);
1718            self.rem_size_override_stack.pop();
1719            result
1720        } else {
1721            f(self)
1722        }
1723    }
1724
1725    /// The line height associated with the current text style.
1726    pub fn line_height(&self) -> Pixels {
1727        self.text_style().line_height_in_pixels(self.rem_size())
1728    }
1729
1730    /// Call to prevent the default action of an event. Currently only used to prevent
1731    /// parent elements from becoming focused on mouse down.
1732    pub fn prevent_default(&mut self) {
1733        self.default_prevented = true;
1734    }
1735
1736    /// Obtain whether default has been prevented for the event currently being dispatched.
1737    pub fn default_prevented(&self) -> bool {
1738        self.default_prevented
1739    }
1740
1741    /// Determine whether the given action is available along the dispatch path to the currently focused element.
1742    pub fn is_action_available(&self, action: &dyn Action, cx: &mut App) -> bool {
1743        let node_id =
1744            self.focus_node_id_in_rendered_frame(self.focused(cx).map(|handle| handle.id));
1745        self.rendered_frame
1746            .dispatch_tree
1747            .is_action_available(action, node_id)
1748    }
1749
1750    /// The position of the mouse relative to the window.
1751    pub fn mouse_position(&self) -> Point<Pixels> {
1752        self.mouse_position
1753    }
1754
1755    /// The current state of the keyboard's modifiers
1756    pub fn modifiers(&self) -> Modifiers {
1757        self.modifiers
1758    }
1759
1760    /// The current state of the keyboard's capslock
1761    pub fn capslock(&self) -> Capslock {
1762        self.capslock
1763    }
1764
1765    fn complete_frame(&self) {
1766        self.platform_window.completed_frame();
1767    }
1768
1769    /// Produces a new frame and assigns it to `rendered_frame`. To actually show
1770    /// the contents of the new [Scene], use [present].
1771    #[profiling::function]
1772    pub fn draw(&mut self, cx: &mut App) -> ArenaClearNeeded {
1773        self.invalidate_entities();
1774        cx.entities.clear_accessed();
1775        debug_assert!(self.rendered_entity_stack.is_empty());
1776        self.invalidator.set_dirty(false);
1777        self.requested_autoscroll = None;
1778
1779        // Restore the previously-used input handler.
1780        if let Some(input_handler) = self.platform_window.take_input_handler() {
1781            self.rendered_frame.input_handlers.push(Some(input_handler));
1782        }
1783        self.draw_roots(cx);
1784        self.dirty_views.clear();
1785        self.next_frame.window_active = self.active.get();
1786
1787        // Register requested input handler with the platform window.
1788        if let Some(input_handler) = self.next_frame.input_handlers.pop() {
1789            self.platform_window
1790                .set_input_handler(input_handler.unwrap());
1791        }
1792
1793        self.layout_engine.as_mut().unwrap().clear();
1794        self.text_system().finish_frame();
1795        self.next_frame.finish(&mut self.rendered_frame);
1796
1797        self.invalidator.set_phase(DrawPhase::Focus);
1798        let previous_focus_path = self.rendered_frame.focus_path();
1799        let previous_window_active = self.rendered_frame.window_active;
1800        mem::swap(&mut self.rendered_frame, &mut self.next_frame);
1801        self.next_frame.clear();
1802        let current_focus_path = self.rendered_frame.focus_path();
1803        let current_window_active = self.rendered_frame.window_active;
1804
1805        if previous_focus_path != current_focus_path
1806            || previous_window_active != current_window_active
1807        {
1808            if !previous_focus_path.is_empty() && current_focus_path.is_empty() {
1809                self.focus_lost_listeners
1810                    .clone()
1811                    .retain(&(), |listener| listener(self, cx));
1812            }
1813
1814            let event = WindowFocusEvent {
1815                previous_focus_path: if previous_window_active {
1816                    previous_focus_path
1817                } else {
1818                    Default::default()
1819                },
1820                current_focus_path: if current_window_active {
1821                    current_focus_path
1822                } else {
1823                    Default::default()
1824                },
1825            };
1826            self.focus_listeners
1827                .clone()
1828                .retain(&(), |listener| listener(&event, self, cx));
1829        }
1830
1831        debug_assert!(self.rendered_entity_stack.is_empty());
1832        self.record_entities_accessed(cx);
1833        self.reset_cursor_style(cx);
1834        self.refreshing = false;
1835        self.invalidator.set_phase(DrawPhase::None);
1836        self.needs_present.set(true);
1837
1838        ArenaClearNeeded
1839    }
1840
1841    fn record_entities_accessed(&mut self, cx: &mut App) {
1842        let mut entities_ref = cx.entities.accessed_entities.borrow_mut();
1843        let mut entities = mem::take(entities_ref.deref_mut());
1844        drop(entities_ref);
1845        let handle = self.handle;
1846        cx.record_entities_accessed(
1847            handle,
1848            // Try moving window invalidator into the Window
1849            self.invalidator.clone(),
1850            &entities,
1851        );
1852        let mut entities_ref = cx.entities.accessed_entities.borrow_mut();
1853        mem::swap(&mut entities, entities_ref.deref_mut());
1854    }
1855
1856    fn invalidate_entities(&mut self) {
1857        let mut views = self.invalidator.take_views();
1858        for entity in views.drain() {
1859            self.mark_view_dirty(entity);
1860        }
1861        self.invalidator.replace_views(views);
1862    }
1863
1864    #[profiling::function]
1865    fn present(&self) {
1866        self.platform_window.draw(&self.rendered_frame.scene);
1867        self.needs_present.set(false);
1868        profiling::finish_frame!();
1869    }
1870
1871    fn draw_roots(&mut self, cx: &mut App) {
1872        self.invalidator.set_phase(DrawPhase::Prepaint);
1873        self.tooltip_bounds.take();
1874
1875        let _inspector_width: Pixels = rems(30.0).to_pixels(self.rem_size());
1876        let root_size = {
1877            #[cfg(any(feature = "inspector", debug_assertions))]
1878            {
1879                if self.inspector.is_some() {
1880                    let mut size = self.viewport_size;
1881                    size.width = (size.width - _inspector_width).max(px(0.0));
1882                    size
1883                } else {
1884                    self.viewport_size
1885                }
1886            }
1887            #[cfg(not(any(feature = "inspector", debug_assertions)))]
1888            {
1889                self.viewport_size
1890            }
1891        };
1892
1893        // Layout all root elements.
1894        let mut root_element = self.root.as_ref().unwrap().clone().into_any();
1895        root_element.prepaint_as_root(Point::default(), root_size.into(), self, cx);
1896
1897        #[cfg(any(feature = "inspector", debug_assertions))]
1898        let inspector_element = self.prepaint_inspector(_inspector_width, cx);
1899
1900        let mut sorted_deferred_draws =
1901            (0..self.next_frame.deferred_draws.len()).collect::<SmallVec<[_; 8]>>();
1902        sorted_deferred_draws.sort_by_key(|ix| self.next_frame.deferred_draws[*ix].priority);
1903        self.prepaint_deferred_draws(&sorted_deferred_draws, cx);
1904
1905        let mut prompt_element = None;
1906        let mut active_drag_element = None;
1907        let mut tooltip_element = None;
1908        if let Some(prompt) = self.prompt.take() {
1909            let mut element = prompt.view.any_view().into_any();
1910            element.prepaint_as_root(Point::default(), root_size.into(), self, cx);
1911            prompt_element = Some(element);
1912            self.prompt = Some(prompt);
1913        } else if let Some(active_drag) = cx.active_drag.take() {
1914            let mut element = active_drag.view.clone().into_any();
1915            let offset = self.mouse_position() - active_drag.cursor_offset;
1916            element.prepaint_as_root(offset, AvailableSpace::min_size(), self, cx);
1917            active_drag_element = Some(element);
1918            cx.active_drag = Some(active_drag);
1919        } else {
1920            tooltip_element = self.prepaint_tooltip(cx);
1921        }
1922
1923        self.mouse_hit_test = self.next_frame.hit_test(self.mouse_position);
1924
1925        // Now actually paint the elements.
1926        self.invalidator.set_phase(DrawPhase::Paint);
1927        root_element.paint(self, cx);
1928
1929        #[cfg(any(feature = "inspector", debug_assertions))]
1930        self.paint_inspector(inspector_element, cx);
1931
1932        self.paint_deferred_draws(&sorted_deferred_draws, cx);
1933
1934        if let Some(mut prompt_element) = prompt_element {
1935            prompt_element.paint(self, cx);
1936        } else if let Some(mut drag_element) = active_drag_element {
1937            drag_element.paint(self, cx);
1938        } else if let Some(mut tooltip_element) = tooltip_element {
1939            tooltip_element.paint(self, cx);
1940        }
1941
1942        #[cfg(any(feature = "inspector", debug_assertions))]
1943        self.paint_inspector_hitbox(cx);
1944    }
1945
1946    fn prepaint_tooltip(&mut self, cx: &mut App) -> Option<AnyElement> {
1947        // Use indexing instead of iteration to avoid borrowing self for the duration of the loop.
1948        for tooltip_request_index in (0..self.next_frame.tooltip_requests.len()).rev() {
1949            let Some(Some(tooltip_request)) = self
1950                .next_frame
1951                .tooltip_requests
1952                .get(tooltip_request_index)
1953                .cloned()
1954            else {
1955                log::error!("Unexpectedly absent TooltipRequest");
1956                continue;
1957            };
1958            let mut element = tooltip_request.tooltip.view.clone().into_any();
1959            let mouse_position = tooltip_request.tooltip.mouse_position;
1960            let tooltip_size = element.layout_as_root(AvailableSpace::min_size(), self, cx);
1961
1962            let mut tooltip_bounds =
1963                Bounds::new(mouse_position + point(px(1.), px(1.)), tooltip_size);
1964            let window_bounds = Bounds {
1965                origin: Point::default(),
1966                size: self.viewport_size(),
1967            };
1968
1969            if tooltip_bounds.right() > window_bounds.right() {
1970                let new_x = mouse_position.x - tooltip_bounds.size.width - px(1.);
1971                if new_x >= Pixels::ZERO {
1972                    tooltip_bounds.origin.x = new_x;
1973                } else {
1974                    tooltip_bounds.origin.x = cmp::max(
1975                        Pixels::ZERO,
1976                        tooltip_bounds.origin.x - tooltip_bounds.right() - window_bounds.right(),
1977                    );
1978                }
1979            }
1980
1981            if tooltip_bounds.bottom() > window_bounds.bottom() {
1982                let new_y = mouse_position.y - tooltip_bounds.size.height - px(1.);
1983                if new_y >= Pixels::ZERO {
1984                    tooltip_bounds.origin.y = new_y;
1985                } else {
1986                    tooltip_bounds.origin.y = cmp::max(
1987                        Pixels::ZERO,
1988                        tooltip_bounds.origin.y - tooltip_bounds.bottom() - window_bounds.bottom(),
1989                    );
1990                }
1991            }
1992
1993            // It's possible for an element to have an active tooltip while not being painted (e.g.
1994            // via the `visible_on_hover` method). Since mouse listeners are not active in this
1995            // case, instead update the tooltip's visibility here.
1996            let is_visible =
1997                (tooltip_request.tooltip.check_visible_and_update)(tooltip_bounds, self, cx);
1998            if !is_visible {
1999                continue;
2000            }
2001
2002            self.with_absolute_element_offset(tooltip_bounds.origin, |window| {
2003                element.prepaint(window, cx)
2004            });
2005
2006            self.tooltip_bounds = Some(TooltipBounds {
2007                id: tooltip_request.id,
2008                bounds: tooltip_bounds,
2009            });
2010            return Some(element);
2011        }
2012        None
2013    }
2014
2015    fn prepaint_deferred_draws(&mut self, deferred_draw_indices: &[usize], cx: &mut App) {
2016        assert_eq!(self.element_id_stack.len(), 0);
2017
2018        let mut deferred_draws = mem::take(&mut self.next_frame.deferred_draws);
2019        for deferred_draw_ix in deferred_draw_indices {
2020            let deferred_draw = &mut deferred_draws[*deferred_draw_ix];
2021            self.element_id_stack
2022                .clone_from(&deferred_draw.element_id_stack);
2023            self.text_style_stack
2024                .clone_from(&deferred_draw.text_style_stack);
2025            self.next_frame
2026                .dispatch_tree
2027                .set_active_node(deferred_draw.parent_node);
2028
2029            let prepaint_start = self.prepaint_index();
2030            if let Some(element) = deferred_draw.element.as_mut() {
2031                self.with_rendered_view(deferred_draw.current_view, |window| {
2032                    window.with_absolute_element_offset(deferred_draw.absolute_offset, |window| {
2033                        element.prepaint(window, cx)
2034                    });
2035                })
2036            } else {
2037                self.reuse_prepaint(deferred_draw.prepaint_range.clone());
2038            }
2039            let prepaint_end = self.prepaint_index();
2040            deferred_draw.prepaint_range = prepaint_start..prepaint_end;
2041        }
2042        assert_eq!(
2043            self.next_frame.deferred_draws.len(),
2044            0,
2045            "cannot call defer_draw during deferred drawing"
2046        );
2047        self.next_frame.deferred_draws = deferred_draws;
2048        self.element_id_stack.clear();
2049        self.text_style_stack.clear();
2050    }
2051
2052    fn paint_deferred_draws(&mut self, deferred_draw_indices: &[usize], cx: &mut App) {
2053        assert_eq!(self.element_id_stack.len(), 0);
2054
2055        let mut deferred_draws = mem::take(&mut self.next_frame.deferred_draws);
2056        for deferred_draw_ix in deferred_draw_indices {
2057            let mut deferred_draw = &mut deferred_draws[*deferred_draw_ix];
2058            self.element_id_stack
2059                .clone_from(&deferred_draw.element_id_stack);
2060            self.next_frame
2061                .dispatch_tree
2062                .set_active_node(deferred_draw.parent_node);
2063
2064            let paint_start = self.paint_index();
2065            if let Some(element) = deferred_draw.element.as_mut() {
2066                self.with_rendered_view(deferred_draw.current_view, |window| {
2067                    element.paint(window, cx);
2068                })
2069            } else {
2070                self.reuse_paint(deferred_draw.paint_range.clone());
2071            }
2072            let paint_end = self.paint_index();
2073            deferred_draw.paint_range = paint_start..paint_end;
2074        }
2075        self.next_frame.deferred_draws = deferred_draws;
2076        self.element_id_stack.clear();
2077    }
2078
2079    pub(crate) fn prepaint_index(&self) -> PrepaintStateIndex {
2080        PrepaintStateIndex {
2081            hitboxes_index: self.next_frame.hitboxes.len(),
2082            tooltips_index: self.next_frame.tooltip_requests.len(),
2083            deferred_draws_index: self.next_frame.deferred_draws.len(),
2084            dispatch_tree_index: self.next_frame.dispatch_tree.len(),
2085            accessed_element_states_index: self.next_frame.accessed_element_states.len(),
2086            line_layout_index: self.text_system.layout_index(),
2087        }
2088    }
2089
2090    pub(crate) fn reuse_prepaint(&mut self, range: Range<PrepaintStateIndex>) {
2091        self.next_frame.hitboxes.extend(
2092            self.rendered_frame.hitboxes[range.start.hitboxes_index..range.end.hitboxes_index]
2093                .iter()
2094                .cloned(),
2095        );
2096        self.next_frame.tooltip_requests.extend(
2097            self.rendered_frame.tooltip_requests
2098                [range.start.tooltips_index..range.end.tooltips_index]
2099                .iter_mut()
2100                .map(|request| request.take()),
2101        );
2102        self.next_frame.accessed_element_states.extend(
2103            self.rendered_frame.accessed_element_states[range.start.accessed_element_states_index
2104                ..range.end.accessed_element_states_index]
2105                .iter()
2106                .map(|(id, type_id)| (GlobalElementId(id.0.clone()), *type_id)),
2107        );
2108        self.text_system
2109            .reuse_layouts(range.start.line_layout_index..range.end.line_layout_index);
2110
2111        let reused_subtree = self.next_frame.dispatch_tree.reuse_subtree(
2112            range.start.dispatch_tree_index..range.end.dispatch_tree_index,
2113            &mut self.rendered_frame.dispatch_tree,
2114            self.focus,
2115        );
2116
2117        if reused_subtree.contains_focus() {
2118            self.next_frame.focus = self.focus;
2119        }
2120
2121        self.next_frame.deferred_draws.extend(
2122            self.rendered_frame.deferred_draws
2123                [range.start.deferred_draws_index..range.end.deferred_draws_index]
2124                .iter()
2125                .map(|deferred_draw| DeferredDraw {
2126                    current_view: deferred_draw.current_view,
2127                    parent_node: reused_subtree.refresh_node_id(deferred_draw.parent_node),
2128                    element_id_stack: deferred_draw.element_id_stack.clone(),
2129                    text_style_stack: deferred_draw.text_style_stack.clone(),
2130                    priority: deferred_draw.priority,
2131                    element: None,
2132                    absolute_offset: deferred_draw.absolute_offset,
2133                    prepaint_range: deferred_draw.prepaint_range.clone(),
2134                    paint_range: deferred_draw.paint_range.clone(),
2135                }),
2136        );
2137    }
2138
2139    pub(crate) fn paint_index(&self) -> PaintIndex {
2140        PaintIndex {
2141            scene_index: self.next_frame.scene.len(),
2142            mouse_listeners_index: self.next_frame.mouse_listeners.len(),
2143            input_handlers_index: self.next_frame.input_handlers.len(),
2144            cursor_styles_index: self.next_frame.cursor_styles.len(),
2145            accessed_element_states_index: self.next_frame.accessed_element_states.len(),
2146            line_layout_index: self.text_system.layout_index(),
2147        }
2148    }
2149
2150    pub(crate) fn reuse_paint(&mut self, range: Range<PaintIndex>) {
2151        self.next_frame.cursor_styles.extend(
2152            self.rendered_frame.cursor_styles
2153                [range.start.cursor_styles_index..range.end.cursor_styles_index]
2154                .iter()
2155                .cloned(),
2156        );
2157        self.next_frame.input_handlers.extend(
2158            self.rendered_frame.input_handlers
2159                [range.start.input_handlers_index..range.end.input_handlers_index]
2160                .iter_mut()
2161                .map(|handler| handler.take()),
2162        );
2163        self.next_frame.mouse_listeners.extend(
2164            self.rendered_frame.mouse_listeners
2165                [range.start.mouse_listeners_index..range.end.mouse_listeners_index]
2166                .iter_mut()
2167                .map(|listener| listener.take()),
2168        );
2169        self.next_frame.accessed_element_states.extend(
2170            self.rendered_frame.accessed_element_states[range.start.accessed_element_states_index
2171                ..range.end.accessed_element_states_index]
2172                .iter()
2173                .map(|(id, type_id)| (GlobalElementId(id.0.clone()), *type_id)),
2174        );
2175
2176        self.text_system
2177            .reuse_layouts(range.start.line_layout_index..range.end.line_layout_index);
2178        self.next_frame.scene.replay(
2179            range.start.scene_index..range.end.scene_index,
2180            &self.rendered_frame.scene,
2181        );
2182    }
2183
2184    /// Push a text style onto the stack, and call a function with that style active.
2185    /// Use [`Window::text_style`] to get the current, combined text style. This method
2186    /// should only be called as part of element drawing.
2187    pub fn with_text_style<F, R>(&mut self, style: Option<TextStyleRefinement>, f: F) -> R
2188    where
2189        F: FnOnce(&mut Self) -> R,
2190    {
2191        self.invalidator.debug_assert_paint_or_prepaint();
2192        if let Some(style) = style {
2193            self.text_style_stack.push(style);
2194            let result = f(self);
2195            self.text_style_stack.pop();
2196            result
2197        } else {
2198            f(self)
2199        }
2200    }
2201
2202    /// Updates the cursor style at the platform level. This method should only be called
2203    /// during the prepaint phase of element drawing.
2204    pub fn set_cursor_style(&mut self, style: CursorStyle, hitbox: &Hitbox) {
2205        self.invalidator.debug_assert_paint();
2206        self.next_frame.cursor_styles.push(CursorStyleRequest {
2207            hitbox_id: Some(hitbox.id),
2208            style,
2209        });
2210    }
2211
2212    /// Updates the cursor style for the entire window at the platform level. A cursor
2213    /// style using this method will have precedence over any cursor style set using
2214    /// `set_cursor_style`. This method should only be called during the prepaint
2215    /// phase of element drawing.
2216    pub fn set_window_cursor_style(&mut self, style: CursorStyle) {
2217        self.invalidator.debug_assert_paint();
2218        self.next_frame.cursor_styles.push(CursorStyleRequest {
2219            hitbox_id: None,
2220            style,
2221        })
2222    }
2223
2224    /// Sets a tooltip to be rendered for the upcoming frame. This method should only be called
2225    /// during the paint phase of element drawing.
2226    pub fn set_tooltip(&mut self, tooltip: AnyTooltip) -> TooltipId {
2227        self.invalidator.debug_assert_prepaint();
2228        let id = TooltipId(post_inc(&mut self.next_tooltip_id.0));
2229        self.next_frame
2230            .tooltip_requests
2231            .push(Some(TooltipRequest { id, tooltip }));
2232        id
2233    }
2234
2235    /// Invoke the given function with the given content mask after intersecting it
2236    /// with the current mask. This method should only be called during element drawing.
2237    pub fn with_content_mask<R>(
2238        &mut self,
2239        mask: Option<ContentMask<Pixels>>,
2240        f: impl FnOnce(&mut Self) -> R,
2241    ) -> R {
2242        self.invalidator.debug_assert_paint_or_prepaint();
2243        if let Some(mask) = mask {
2244            let mask = mask.intersect(&self.content_mask());
2245            self.content_mask_stack.push(mask);
2246            let result = f(self);
2247            self.content_mask_stack.pop();
2248            result
2249        } else {
2250            f(self)
2251        }
2252    }
2253
2254    /// Updates the global element offset relative to the current offset. This is used to implement
2255    /// scrolling. This method should only be called during the prepaint phase of element drawing.
2256    pub fn with_element_offset<R>(
2257        &mut self,
2258        offset: Point<Pixels>,
2259        f: impl FnOnce(&mut Self) -> R,
2260    ) -> R {
2261        self.invalidator.debug_assert_prepaint();
2262
2263        if offset.is_zero() {
2264            return f(self);
2265        };
2266
2267        let abs_offset = self.element_offset() + offset;
2268        self.with_absolute_element_offset(abs_offset, f)
2269    }
2270
2271    /// Updates the global element offset based on the given offset. This is used to implement
2272    /// drag handles and other manual painting of elements. This method should only be called during
2273    /// the prepaint phase of element drawing.
2274    pub fn with_absolute_element_offset<R>(
2275        &mut self,
2276        offset: Point<Pixels>,
2277        f: impl FnOnce(&mut Self) -> R,
2278    ) -> R {
2279        self.invalidator.debug_assert_prepaint();
2280        self.element_offset_stack.push(offset);
2281        let result = f(self);
2282        self.element_offset_stack.pop();
2283        result
2284    }
2285
2286    pub(crate) fn with_element_opacity<R>(
2287        &mut self,
2288        opacity: Option<f32>,
2289        f: impl FnOnce(&mut Self) -> R,
2290    ) -> R {
2291        if opacity.is_none() {
2292            return f(self);
2293        }
2294
2295        self.invalidator.debug_assert_paint_or_prepaint();
2296        self.element_opacity = opacity;
2297        let result = f(self);
2298        self.element_opacity = None;
2299        result
2300    }
2301
2302    /// Perform prepaint on child elements in a "retryable" manner, so that any side effects
2303    /// of prepaints can be discarded before prepainting again. This is used to support autoscroll
2304    /// where we need to prepaint children to detect the autoscroll bounds, then adjust the
2305    /// element offset and prepaint again. See [`List`] for an example. This method should only be
2306    /// called during the prepaint phase of element drawing.
2307    pub fn transact<T, U>(&mut self, f: impl FnOnce(&mut Self) -> Result<T, U>) -> Result<T, U> {
2308        self.invalidator.debug_assert_prepaint();
2309        let index = self.prepaint_index();
2310        let result = f(self);
2311        if result.is_err() {
2312            self.next_frame.hitboxes.truncate(index.hitboxes_index);
2313            self.next_frame
2314                .tooltip_requests
2315                .truncate(index.tooltips_index);
2316            self.next_frame
2317                .deferred_draws
2318                .truncate(index.deferred_draws_index);
2319            self.next_frame
2320                .dispatch_tree
2321                .truncate(index.dispatch_tree_index);
2322            self.next_frame
2323                .accessed_element_states
2324                .truncate(index.accessed_element_states_index);
2325            self.text_system.truncate_layouts(index.line_layout_index);
2326        }
2327        result
2328    }
2329
2330    /// When you call this method during [`prepaint`], containing elements will attempt to
2331    /// scroll to cause the specified bounds to become visible. When they decide to autoscroll, they will call
2332    /// [`prepaint`] again with a new set of bounds. See [`List`] for an example of an element
2333    /// that supports this method being called on the elements it contains. This method should only be
2334    /// called during the prepaint phase of element drawing.
2335    pub fn request_autoscroll(&mut self, bounds: Bounds<Pixels>) {
2336        self.invalidator.debug_assert_prepaint();
2337        self.requested_autoscroll = Some(bounds);
2338    }
2339
2340    /// This method can be called from a containing element such as [`List`] to support the autoscroll behavior
2341    /// described in [`request_autoscroll`].
2342    pub fn take_autoscroll(&mut self) -> Option<Bounds<Pixels>> {
2343        self.invalidator.debug_assert_prepaint();
2344        self.requested_autoscroll.take()
2345    }
2346
2347    /// Asynchronously load an asset, if the asset hasn't finished loading this will return None.
2348    /// Your view will be re-drawn once the asset has finished loading.
2349    ///
2350    /// Note that the multiple calls to this method will only result in one `Asset::load` call at a
2351    /// time.
2352    pub fn use_asset<A: Asset>(&mut self, source: &A::Source, cx: &mut App) -> Option<A::Output> {
2353        let (task, is_first) = cx.fetch_asset::<A>(source);
2354        task.clone().now_or_never().or_else(|| {
2355            if is_first {
2356                let entity_id = self.current_view();
2357                self.spawn(cx, {
2358                    let task = task.clone();
2359                    async move |cx| {
2360                        task.await;
2361
2362                        cx.on_next_frame(move |_, cx| {
2363                            cx.notify(entity_id);
2364                        });
2365                    }
2366                })
2367                .detach();
2368            }
2369
2370            None
2371        })
2372    }
2373
2374    /// Asynchronously load an asset, if the asset hasn't finished loading or doesn't exist this will return None.
2375    /// Your view will not be re-drawn once the asset has finished loading.
2376    ///
2377    /// Note that the multiple calls to this method will only result in one `Asset::load` call at a
2378    /// time.
2379    pub fn get_asset<A: Asset>(&mut self, source: &A::Source, cx: &mut App) -> Option<A::Output> {
2380        let (task, _) = cx.fetch_asset::<A>(source);
2381        task.clone().now_or_never()
2382    }
2383    /// Obtain the current element offset. This method should only be called during the
2384    /// prepaint phase of element drawing.
2385    pub fn element_offset(&self) -> Point<Pixels> {
2386        self.invalidator.debug_assert_prepaint();
2387        self.element_offset_stack
2388            .last()
2389            .copied()
2390            .unwrap_or_default()
2391    }
2392
2393    /// Obtain the current element opacity. This method should only be called during the
2394    /// prepaint phase of element drawing.
2395    pub(crate) fn element_opacity(&self) -> f32 {
2396        self.invalidator.debug_assert_paint_or_prepaint();
2397        self.element_opacity.unwrap_or(1.0)
2398    }
2399
2400    /// Obtain the current content mask. This method should only be called during element drawing.
2401    pub fn content_mask(&self) -> ContentMask<Pixels> {
2402        self.invalidator.debug_assert_paint_or_prepaint();
2403        self.content_mask_stack
2404            .last()
2405            .cloned()
2406            .unwrap_or_else(|| ContentMask {
2407                bounds: Bounds {
2408                    origin: Point::default(),
2409                    size: self.viewport_size,
2410                },
2411            })
2412    }
2413
2414    /// Provide elements in the called function with a new namespace in which their identifiers must be unique.
2415    /// This can be used within a custom element to distinguish multiple sets of child elements.
2416    pub fn with_element_namespace<R>(
2417        &mut self,
2418        element_id: impl Into<ElementId>,
2419        f: impl FnOnce(&mut Self) -> R,
2420    ) -> R {
2421        self.element_id_stack.push(element_id.into());
2422        let result = f(self);
2423        self.element_id_stack.pop();
2424        result
2425    }
2426
2427    /// Use a piece of state that exists as long this element is being rendered in consecutive frames.
2428    pub fn use_keyed_state<S: 'static>(
2429        &mut self,
2430        key: impl Into<ElementId>,
2431        cx: &mut App,
2432        init: impl FnOnce(&mut Self, &mut App) -> S,
2433    ) -> Entity<S> {
2434        let current_view = self.current_view();
2435        self.with_global_id(key.into(), |global_id, window| {
2436            window.with_element_state(global_id, |state: Option<Entity<S>>, window| {
2437                if let Some(state) = state {
2438                    (state.clone(), state)
2439                } else {
2440                    let new_state = cx.new(|cx| init(window, cx));
2441                    cx.observe(&new_state, move |_, cx| {
2442                        cx.notify(current_view);
2443                    })
2444                    .detach();
2445                    (new_state.clone(), new_state)
2446                }
2447            })
2448        })
2449    }
2450
2451    /// Immediately push an element ID onto the stack. Useful for simplifying IDs in lists
2452    pub fn with_id<R>(&mut self, id: impl Into<ElementId>, f: impl FnOnce(&mut Self) -> R) -> R {
2453        self.with_global_id(id.into(), |_, window| f(window))
2454    }
2455
2456    /// Use a piece of state that exists as long this element is being rendered in consecutive frames, without needing to specify a key
2457    ///
2458    /// NOTE: This method uses the location of the caller to generate an ID for this state.
2459    ///       If this is not sufficient to identify your state (e.g. you're rendering a list item),
2460    ///       you can provide a custom ElementID using the `use_keyed_state` method.
2461    #[track_caller]
2462    pub fn use_state<S: 'static>(
2463        &mut self,
2464        cx: &mut App,
2465        init: impl FnOnce(&mut Self, &mut App) -> S,
2466    ) -> Entity<S> {
2467        self.use_keyed_state(
2468            ElementId::CodeLocation(*core::panic::Location::caller()),
2469            cx,
2470            init,
2471        )
2472    }
2473
2474    /// Updates or initializes state for an element with the given id that lives across multiple
2475    /// frames. If an element with this ID existed in the rendered frame, its state will be passed
2476    /// to the given closure. The state returned by the closure will be stored so it can be referenced
2477    /// when drawing the next frame. This method should only be called as part of element drawing.
2478    pub fn with_element_state<S, R>(
2479        &mut self,
2480        global_id: &GlobalElementId,
2481        f: impl FnOnce(Option<S>, &mut Self) -> (R, S),
2482    ) -> R
2483    where
2484        S: 'static,
2485    {
2486        self.invalidator.debug_assert_paint_or_prepaint();
2487
2488        let key = (GlobalElementId(global_id.0.clone()), TypeId::of::<S>());
2489        self.next_frame
2490            .accessed_element_states
2491            .push((GlobalElementId(key.0.clone()), TypeId::of::<S>()));
2492
2493        if let Some(any) = self
2494            .next_frame
2495            .element_states
2496            .remove(&key)
2497            .or_else(|| self.rendered_frame.element_states.remove(&key))
2498        {
2499            let ElementStateBox {
2500                inner,
2501                #[cfg(debug_assertions)]
2502                type_name,
2503            } = any;
2504            // Using the extra inner option to avoid needing to reallocate a new box.
2505            let mut state_box = inner
2506                .downcast::<Option<S>>()
2507                .map_err(|_| {
2508                    #[cfg(debug_assertions)]
2509                    {
2510                        anyhow::anyhow!(
2511                            "invalid element state type for id, requested {:?}, actual: {:?}",
2512                            std::any::type_name::<S>(),
2513                            type_name
2514                        )
2515                    }
2516
2517                    #[cfg(not(debug_assertions))]
2518                    {
2519                        anyhow::anyhow!(
2520                            "invalid element state type for id, requested {:?}",
2521                            std::any::type_name::<S>(),
2522                        )
2523                    }
2524                })
2525                .unwrap();
2526
2527            let state = state_box.take().expect(
2528                "reentrant call to with_element_state for the same state type and element id",
2529            );
2530            let (result, state) = f(Some(state), self);
2531            state_box.replace(state);
2532            self.next_frame.element_states.insert(
2533                key,
2534                ElementStateBox {
2535                    inner: state_box,
2536                    #[cfg(debug_assertions)]
2537                    type_name,
2538                },
2539            );
2540            result
2541        } else {
2542            let (result, state) = f(None, self);
2543            self.next_frame.element_states.insert(
2544                key,
2545                ElementStateBox {
2546                    inner: Box::new(Some(state)),
2547                    #[cfg(debug_assertions)]
2548                    type_name: std::any::type_name::<S>(),
2549                },
2550            );
2551            result
2552        }
2553    }
2554
2555    /// A variant of `with_element_state` that allows the element's id to be optional. This is a convenience
2556    /// method for elements where the element id may or may not be assigned. Prefer using `with_element_state`
2557    /// when the element is guaranteed to have an id.
2558    ///
2559    /// The first option means 'no ID provided'
2560    /// The second option means 'not yet initialized'
2561    pub fn with_optional_element_state<S, R>(
2562        &mut self,
2563        global_id: Option<&GlobalElementId>,
2564        f: impl FnOnce(Option<Option<S>>, &mut Self) -> (R, Option<S>),
2565    ) -> R
2566    where
2567        S: 'static,
2568    {
2569        self.invalidator.debug_assert_paint_or_prepaint();
2570
2571        if let Some(global_id) = global_id {
2572            self.with_element_state(global_id, |state, cx| {
2573                let (result, state) = f(Some(state), cx);
2574                let state =
2575                    state.expect("you must return some state when you pass some element id");
2576                (result, state)
2577            })
2578        } else {
2579            let (result, state) = f(None, self);
2580            debug_assert!(
2581                state.is_none(),
2582                "you must not return an element state when passing None for the global id"
2583            );
2584            result
2585        }
2586    }
2587
2588    /// Defers the drawing of the given element, scheduling it to be painted on top of the currently-drawn tree
2589    /// at a later time. The `priority` parameter determines the drawing order relative to other deferred elements,
2590    /// with higher values being drawn on top.
2591    ///
2592    /// This method should only be called as part of the prepaint phase of element drawing.
2593    pub fn defer_draw(
2594        &mut self,
2595        element: AnyElement,
2596        absolute_offset: Point<Pixels>,
2597        priority: usize,
2598    ) {
2599        self.invalidator.debug_assert_prepaint();
2600        let parent_node = self.next_frame.dispatch_tree.active_node_id().unwrap();
2601        self.next_frame.deferred_draws.push(DeferredDraw {
2602            current_view: self.current_view(),
2603            parent_node,
2604            element_id_stack: self.element_id_stack.clone(),
2605            text_style_stack: self.text_style_stack.clone(),
2606            priority,
2607            element: Some(element),
2608            absolute_offset,
2609            prepaint_range: PrepaintStateIndex::default()..PrepaintStateIndex::default(),
2610            paint_range: PaintIndex::default()..PaintIndex::default(),
2611        });
2612    }
2613
2614    /// Creates a new painting layer for the specified bounds. A "layer" is a batch
2615    /// of geometry that are non-overlapping and have the same draw order. This is typically used
2616    /// for performance reasons.
2617    ///
2618    /// This method should only be called as part of the paint phase of element drawing.
2619    pub fn paint_layer<R>(&mut self, bounds: Bounds<Pixels>, f: impl FnOnce(&mut Self) -> R) -> R {
2620        self.invalidator.debug_assert_paint();
2621
2622        let scale_factor = self.scale_factor();
2623        let content_mask = self.content_mask();
2624        let clipped_bounds = bounds.intersect(&content_mask.bounds);
2625        if !clipped_bounds.is_empty() {
2626            self.next_frame
2627                .scene
2628                .push_layer(clipped_bounds.scale(scale_factor));
2629        }
2630
2631        let result = f(self);
2632
2633        if !clipped_bounds.is_empty() {
2634            self.next_frame.scene.pop_layer();
2635        }
2636
2637        result
2638    }
2639
2640    /// Paint one or more drop shadows into the scene for the next frame at the current z-index.
2641    ///
2642    /// This method should only be called as part of the paint phase of element drawing.
2643    pub fn paint_shadows(
2644        &mut self,
2645        bounds: Bounds<Pixels>,
2646        corner_radii: Corners<Pixels>,
2647        shadows: &[BoxShadow],
2648    ) {
2649        self.invalidator.debug_assert_paint();
2650
2651        let scale_factor = self.scale_factor();
2652        let content_mask = self.content_mask();
2653        let opacity = self.element_opacity();
2654        for shadow in shadows {
2655            let shadow_bounds = (bounds + shadow.offset).dilate(shadow.spread_radius);
2656            self.next_frame.scene.insert_primitive(Shadow {
2657                order: 0,
2658                blur_radius: shadow.blur_radius.scale(scale_factor),
2659                bounds: shadow_bounds.scale(scale_factor),
2660                content_mask: content_mask.scale(scale_factor),
2661                corner_radii: corner_radii.scale(scale_factor),
2662                color: shadow.color.opacity(opacity),
2663            });
2664        }
2665    }
2666
2667    /// Paint one or more quads into the scene for the next frame at the current stacking context.
2668    /// Quads are colored rectangular regions with an optional background, border, and corner radius.
2669    /// see [`fill`](crate::fill), [`outline`](crate::outline), and [`quad`](crate::quad) to construct this type.
2670    ///
2671    /// This method should only be called as part of the paint phase of element drawing.
2672    ///
2673    /// Note that the `quad.corner_radii` are allowed to exceed the bounds, creating sharp corners
2674    /// where the circular arcs meet. This will not display well when combined with dashed borders.
2675    /// Use `Corners::clamp_radii_for_quad_size` if the radii should fit within the bounds.
2676    pub fn paint_quad(&mut self, quad: PaintQuad) {
2677        self.invalidator.debug_assert_paint();
2678
2679        let scale_factor = self.scale_factor();
2680        let content_mask = self.content_mask();
2681        let opacity = self.element_opacity();
2682        self.next_frame.scene.insert_primitive(Quad {
2683            order: 0,
2684            bounds: quad.bounds.scale(scale_factor),
2685            content_mask: content_mask.scale(scale_factor),
2686            background: quad.background.opacity(opacity),
2687            border_color: quad.border_color.opacity(opacity),
2688            corner_radii: quad.corner_radii.scale(scale_factor),
2689            border_widths: quad.border_widths.scale(scale_factor),
2690            border_style: quad.border_style,
2691        });
2692    }
2693
2694    /// Paint the given `Path` into the scene for the next frame at the current z-index.
2695    ///
2696    /// This method should only be called as part of the paint phase of element drawing.
2697    pub fn paint_path(&mut self, mut path: Path<Pixels>, color: impl Into<Background>) {
2698        self.invalidator.debug_assert_paint();
2699
2700        let scale_factor = self.scale_factor();
2701        let content_mask = self.content_mask();
2702        let opacity = self.element_opacity();
2703        path.content_mask = content_mask;
2704        let color: Background = color.into();
2705        path.color = color.opacity(opacity);
2706        self.next_frame
2707            .scene
2708            .insert_primitive(path.scale(scale_factor));
2709    }
2710
2711    /// Paint an underline into the scene for the next frame at the current z-index.
2712    ///
2713    /// This method should only be called as part of the paint phase of element drawing.
2714    pub fn paint_underline(
2715        &mut self,
2716        origin: Point<Pixels>,
2717        width: Pixels,
2718        style: &UnderlineStyle,
2719    ) {
2720        self.invalidator.debug_assert_paint();
2721
2722        let scale_factor = self.scale_factor();
2723        let height = if style.wavy {
2724            style.thickness * 3.
2725        } else {
2726            style.thickness
2727        };
2728        let bounds = Bounds {
2729            origin,
2730            size: size(width, height),
2731        };
2732        let content_mask = self.content_mask();
2733        let element_opacity = self.element_opacity();
2734
2735        self.next_frame.scene.insert_primitive(Underline {
2736            order: 0,
2737            pad: 0,
2738            bounds: bounds.scale(scale_factor),
2739            content_mask: content_mask.scale(scale_factor),
2740            color: style.color.unwrap_or_default().opacity(element_opacity),
2741            thickness: style.thickness.scale(scale_factor),
2742            wavy: style.wavy,
2743        });
2744    }
2745
2746    /// Paint a strikethrough into the scene for the next frame at the current z-index.
2747    ///
2748    /// This method should only be called as part of the paint phase of element drawing.
2749    pub fn paint_strikethrough(
2750        &mut self,
2751        origin: Point<Pixels>,
2752        width: Pixels,
2753        style: &StrikethroughStyle,
2754    ) {
2755        self.invalidator.debug_assert_paint();
2756
2757        let scale_factor = self.scale_factor();
2758        let height = style.thickness;
2759        let bounds = Bounds {
2760            origin,
2761            size: size(width, height),
2762        };
2763        let content_mask = self.content_mask();
2764        let opacity = self.element_opacity();
2765
2766        self.next_frame.scene.insert_primitive(Underline {
2767            order: 0,
2768            pad: 0,
2769            bounds: bounds.scale(scale_factor),
2770            content_mask: content_mask.scale(scale_factor),
2771            thickness: style.thickness.scale(scale_factor),
2772            color: style.color.unwrap_or_default().opacity(opacity),
2773            wavy: false,
2774        });
2775    }
2776
2777    /// Paints a monochrome (non-emoji) glyph into the scene for the next frame at the current z-index.
2778    ///
2779    /// The y component of the origin is the baseline of the glyph.
2780    /// You should generally prefer to use the [`ShapedLine::paint`](crate::ShapedLine::paint) or
2781    /// [`WrappedLine::paint`](crate::WrappedLine::paint) methods in the [`TextSystem`](crate::TextSystem).
2782    /// This method is only useful if you need to paint a single glyph that has already been shaped.
2783    ///
2784    /// This method should only be called as part of the paint phase of element drawing.
2785    pub fn paint_glyph(
2786        &mut self,
2787        origin: Point<Pixels>,
2788        font_id: FontId,
2789        glyph_id: GlyphId,
2790        font_size: Pixels,
2791        color: Hsla,
2792    ) -> Result<()> {
2793        self.invalidator.debug_assert_paint();
2794
2795        let element_opacity = self.element_opacity();
2796        let scale_factor = self.scale_factor();
2797        let glyph_origin = origin.scale(scale_factor);
2798        let subpixel_variant = Point {
2799            x: (glyph_origin.x.0.fract() * SUBPIXEL_VARIANTS as f32).floor() as u8,
2800            y: (glyph_origin.y.0.fract() * SUBPIXEL_VARIANTS as f32).floor() as u8,
2801        };
2802        let params = RenderGlyphParams {
2803            font_id,
2804            glyph_id,
2805            font_size,
2806            subpixel_variant,
2807            scale_factor,
2808            is_emoji: false,
2809        };
2810
2811        let raster_bounds = self.text_system().raster_bounds(&params)?;
2812        if !raster_bounds.is_zero() {
2813            let tile = self
2814                .sprite_atlas
2815                .get_or_insert_with(&params.clone().into(), &mut || {
2816                    let (size, bytes) = self.text_system().rasterize_glyph(&params)?;
2817                    Ok(Some((size, Cow::Owned(bytes))))
2818                })?
2819                .expect("Callback above only errors or returns Some");
2820            let bounds = Bounds {
2821                origin: glyph_origin.map(|px| px.floor()) + raster_bounds.origin.map(Into::into),
2822                size: tile.bounds.size.map(Into::into),
2823            };
2824            let content_mask = self.content_mask().scale(scale_factor);
2825            self.next_frame.scene.insert_primitive(MonochromeSprite {
2826                order: 0,
2827                pad: 0,
2828                bounds,
2829                content_mask,
2830                color: color.opacity(element_opacity),
2831                tile,
2832                transformation: TransformationMatrix::unit(),
2833            });
2834        }
2835        Ok(())
2836    }
2837
2838    /// Paints an emoji glyph into the scene for the next frame at the current z-index.
2839    ///
2840    /// The y component of the origin is the baseline of the glyph.
2841    /// You should generally prefer to use the [`ShapedLine::paint`](crate::ShapedLine::paint) or
2842    /// [`WrappedLine::paint`](crate::WrappedLine::paint) methods in the [`TextSystem`](crate::TextSystem).
2843    /// This method is only useful if you need to paint a single emoji that has already been shaped.
2844    ///
2845    /// This method should only be called as part of the paint phase of element drawing.
2846    pub fn paint_emoji(
2847        &mut self,
2848        origin: Point<Pixels>,
2849        font_id: FontId,
2850        glyph_id: GlyphId,
2851        font_size: Pixels,
2852    ) -> Result<()> {
2853        self.invalidator.debug_assert_paint();
2854
2855        let scale_factor = self.scale_factor();
2856        let glyph_origin = origin.scale(scale_factor);
2857        let params = RenderGlyphParams {
2858            font_id,
2859            glyph_id,
2860            font_size,
2861            // We don't render emojis with subpixel variants.
2862            subpixel_variant: Default::default(),
2863            scale_factor,
2864            is_emoji: true,
2865        };
2866
2867        let raster_bounds = self.text_system().raster_bounds(&params)?;
2868        if !raster_bounds.is_zero() {
2869            let tile = self
2870                .sprite_atlas
2871                .get_or_insert_with(&params.clone().into(), &mut || {
2872                    let (size, bytes) = self.text_system().rasterize_glyph(&params)?;
2873                    Ok(Some((size, Cow::Owned(bytes))))
2874                })?
2875                .expect("Callback above only errors or returns Some");
2876
2877            let bounds = Bounds {
2878                origin: glyph_origin.map(|px| px.floor()) + raster_bounds.origin.map(Into::into),
2879                size: tile.bounds.size.map(Into::into),
2880            };
2881            let content_mask = self.content_mask().scale(scale_factor);
2882            let opacity = self.element_opacity();
2883
2884            self.next_frame.scene.insert_primitive(PolychromeSprite {
2885                order: 0,
2886                pad: 0,
2887                grayscale: false,
2888                bounds,
2889                corner_radii: Default::default(),
2890                content_mask,
2891                tile,
2892                opacity,
2893            });
2894        }
2895        Ok(())
2896    }
2897
2898    /// Paint a monochrome SVG into the scene for the next frame at the current stacking context.
2899    ///
2900    /// This method should only be called as part of the paint phase of element drawing.
2901    pub fn paint_svg(
2902        &mut self,
2903        bounds: Bounds<Pixels>,
2904        path: SharedString,
2905        transformation: TransformationMatrix,
2906        color: Hsla,
2907        cx: &App,
2908    ) -> Result<()> {
2909        self.invalidator.debug_assert_paint();
2910
2911        let element_opacity = self.element_opacity();
2912        let scale_factor = self.scale_factor();
2913        let bounds = bounds.scale(scale_factor);
2914        let params = RenderSvgParams {
2915            path,
2916            size: bounds.size.map(|pixels| {
2917                DevicePixels::from((pixels.0 * SMOOTH_SVG_SCALE_FACTOR).ceil() as i32)
2918            }),
2919        };
2920
2921        let Some(tile) =
2922            self.sprite_atlas
2923                .get_or_insert_with(&params.clone().into(), &mut || {
2924                    let Some(bytes) = cx.svg_renderer.render(&params)? else {
2925                        return Ok(None);
2926                    };
2927                    Ok(Some((params.size, Cow::Owned(bytes))))
2928                })?
2929        else {
2930            return Ok(());
2931        };
2932        let content_mask = self.content_mask().scale(scale_factor);
2933
2934        self.next_frame.scene.insert_primitive(MonochromeSprite {
2935            order: 0,
2936            pad: 0,
2937            bounds: bounds
2938                .map_origin(|origin| origin.floor())
2939                .map_size(|size| size.ceil()),
2940            content_mask,
2941            color: color.opacity(element_opacity),
2942            tile,
2943            transformation,
2944        });
2945
2946        Ok(())
2947    }
2948
2949    /// Paint an image into the scene for the next frame at the current z-index.
2950    /// This method will panic if the frame_index is not valid
2951    ///
2952    /// This method should only be called as part of the paint phase of element drawing.
2953    pub fn paint_image(
2954        &mut self,
2955        bounds: Bounds<Pixels>,
2956        corner_radii: Corners<Pixels>,
2957        data: Arc<RenderImage>,
2958        frame_index: usize,
2959        grayscale: bool,
2960    ) -> Result<()> {
2961        self.invalidator.debug_assert_paint();
2962
2963        let scale_factor = self.scale_factor();
2964        let bounds = bounds.scale(scale_factor);
2965        let params = RenderImageParams {
2966            image_id: data.id,
2967            frame_index,
2968        };
2969
2970        let tile = self
2971            .sprite_atlas
2972            .get_or_insert_with(&params.clone().into(), &mut || {
2973                Ok(Some((
2974                    data.size(frame_index),
2975                    Cow::Borrowed(
2976                        data.as_bytes(frame_index)
2977                            .expect("It's the caller's job to pass a valid frame index"),
2978                    ),
2979                )))
2980            })?
2981            .expect("Callback above only returns Some");
2982        let content_mask = self.content_mask().scale(scale_factor);
2983        let corner_radii = corner_radii.scale(scale_factor);
2984        let opacity = self.element_opacity();
2985
2986        self.next_frame.scene.insert_primitive(PolychromeSprite {
2987            order: 0,
2988            pad: 0,
2989            grayscale,
2990            bounds: bounds
2991                .map_origin(|origin| origin.floor())
2992                .map_size(|size| size.ceil()),
2993            content_mask,
2994            corner_radii,
2995            tile,
2996            opacity,
2997        });
2998        Ok(())
2999    }
3000
3001    /// Paint a surface into the scene for the next frame at the current z-index.
3002    ///
3003    /// This method should only be called as part of the paint phase of element drawing.
3004    #[cfg(target_os = "macos")]
3005    pub fn paint_surface(&mut self, bounds: Bounds<Pixels>, image_buffer: CVPixelBuffer) {
3006        use crate::PaintSurface;
3007
3008        self.invalidator.debug_assert_paint();
3009
3010        let scale_factor = self.scale_factor();
3011        let bounds = bounds.scale(scale_factor);
3012        let content_mask = self.content_mask().scale(scale_factor);
3013        self.next_frame.scene.insert_primitive(PaintSurface {
3014            order: 0,
3015            bounds,
3016            content_mask,
3017            image_buffer,
3018        });
3019    }
3020
3021    /// Removes an image from the sprite atlas.
3022    pub fn drop_image(&mut self, data: Arc<RenderImage>) -> Result<()> {
3023        for frame_index in 0..data.frame_count() {
3024            let params = RenderImageParams {
3025                image_id: data.id,
3026                frame_index,
3027            };
3028
3029            self.sprite_atlas.remove(&params.clone().into());
3030        }
3031
3032        Ok(())
3033    }
3034
3035    /// Add a node to the layout tree for the current frame. Takes the `Style` of the element for which
3036    /// layout is being requested, along with the layout ids of any children. This method is called during
3037    /// calls to the [`Element::request_layout`] trait method and enables any element to participate in layout.
3038    ///
3039    /// This method should only be called as part of the request_layout or prepaint phase of element drawing.
3040    #[must_use]
3041    pub fn request_layout(
3042        &mut self,
3043        style: Style,
3044        children: impl IntoIterator<Item = LayoutId>,
3045        cx: &mut App,
3046    ) -> LayoutId {
3047        self.invalidator.debug_assert_prepaint();
3048
3049        cx.layout_id_buffer.clear();
3050        cx.layout_id_buffer.extend(children);
3051        let rem_size = self.rem_size();
3052
3053        self.layout_engine
3054            .as_mut()
3055            .unwrap()
3056            .request_layout(style, rem_size, &cx.layout_id_buffer)
3057    }
3058
3059    /// Add a node to the layout tree for the current frame. Instead of taking a `Style` and children,
3060    /// this variant takes a function that is invoked during layout so you can use arbitrary logic to
3061    /// determine the element's size. One place this is used internally is when measuring text.
3062    ///
3063    /// The given closure is invoked at layout time with the known dimensions and available space and
3064    /// returns a `Size`.
3065    ///
3066    /// This method should only be called as part of the request_layout or prepaint phase of element drawing.
3067    pub fn request_measured_layout<
3068        F: FnMut(Size<Option<Pixels>>, Size<AvailableSpace>, &mut Window, &mut App) -> Size<Pixels>
3069            + 'static,
3070    >(
3071        &mut self,
3072        style: Style,
3073        measure: F,
3074    ) -> LayoutId {
3075        self.invalidator.debug_assert_prepaint();
3076
3077        let rem_size = self.rem_size();
3078        self.layout_engine
3079            .as_mut()
3080            .unwrap()
3081            .request_measured_layout(style, rem_size, measure)
3082    }
3083
3084    /// Compute the layout for the given id within the given available space.
3085    /// This method is called for its side effect, typically by the framework prior to painting.
3086    /// After calling it, you can request the bounds of the given layout node id or any descendant.
3087    ///
3088    /// This method should only be called as part of the prepaint phase of element drawing.
3089    pub fn compute_layout(
3090        &mut self,
3091        layout_id: LayoutId,
3092        available_space: Size<AvailableSpace>,
3093        cx: &mut App,
3094    ) {
3095        self.invalidator.debug_assert_prepaint();
3096
3097        let mut layout_engine = self.layout_engine.take().unwrap();
3098        layout_engine.compute_layout(layout_id, available_space, self, cx);
3099        self.layout_engine = Some(layout_engine);
3100    }
3101
3102    /// Obtain the bounds computed for the given LayoutId relative to the window. This method will usually be invoked by
3103    /// GPUI itself automatically in order to pass your element its `Bounds` automatically.
3104    ///
3105    /// This method should only be called as part of element drawing.
3106    pub fn layout_bounds(&mut self, layout_id: LayoutId) -> Bounds<Pixels> {
3107        self.invalidator.debug_assert_prepaint();
3108
3109        let mut bounds = self
3110            .layout_engine
3111            .as_mut()
3112            .unwrap()
3113            .layout_bounds(layout_id)
3114            .map(Into::into);
3115        bounds.origin += self.element_offset();
3116        bounds
3117    }
3118
3119    /// This method should be called during `prepaint`. You can use
3120    /// the returned [Hitbox] during `paint` or in an event handler
3121    /// to determine whether the inserted hitbox was the topmost.
3122    ///
3123    /// This method should only be called as part of the prepaint phase of element drawing.
3124    pub fn insert_hitbox(&mut self, bounds: Bounds<Pixels>, behavior: HitboxBehavior) -> Hitbox {
3125        self.invalidator.debug_assert_prepaint();
3126
3127        let content_mask = self.content_mask();
3128        let mut id = self.next_hitbox_id;
3129        self.next_hitbox_id = self.next_hitbox_id.next();
3130        let hitbox = Hitbox {
3131            id,
3132            bounds,
3133            content_mask,
3134            behavior,
3135        };
3136        self.next_frame.hitboxes.push(hitbox.clone());
3137        hitbox
3138    }
3139
3140    /// Set a hitbox which will act as a control area of the platform window.
3141    ///
3142    /// This method should only be called as part of the paint phase of element drawing.
3143    pub fn insert_window_control_hitbox(&mut self, area: WindowControlArea, hitbox: Hitbox) {
3144        self.invalidator.debug_assert_paint();
3145        self.next_frame.window_control_hitboxes.push((area, hitbox));
3146    }
3147
3148    /// Sets the key context for the current element. This context will be used to translate
3149    /// keybindings into actions.
3150    ///
3151    /// This method should only be called as part of the paint phase of element drawing.
3152    pub fn set_key_context(&mut self, context: KeyContext) {
3153        self.invalidator.debug_assert_paint();
3154        self.next_frame.dispatch_tree.set_key_context(context);
3155    }
3156
3157    /// Sets the focus handle for the current element. This handle will be used to manage focus state
3158    /// and keyboard event dispatch for the element.
3159    ///
3160    /// This method should only be called as part of the prepaint phase of element drawing.
3161    pub fn set_focus_handle(&mut self, focus_handle: &FocusHandle, _: &App) {
3162        self.invalidator.debug_assert_prepaint();
3163        if focus_handle.is_focused(self) {
3164            self.next_frame.focus = Some(focus_handle.id);
3165        }
3166        self.next_frame.dispatch_tree.set_focus_id(focus_handle.id);
3167    }
3168
3169    /// Sets the view id for the current element, which will be used to manage view caching.
3170    ///
3171    /// This method should only be called as part of element prepaint. We plan on removing this
3172    /// method eventually when we solve some issues that require us to construct editor elements
3173    /// directly instead of always using editors via views.
3174    pub fn set_view_id(&mut self, view_id: EntityId) {
3175        self.invalidator.debug_assert_prepaint();
3176        self.next_frame.dispatch_tree.set_view_id(view_id);
3177    }
3178
3179    /// Get the entity ID for the currently rendering view
3180    pub fn current_view(&self) -> EntityId {
3181        self.invalidator.debug_assert_paint_or_prepaint();
3182        self.rendered_entity_stack.last().copied().unwrap()
3183    }
3184
3185    pub(crate) fn with_rendered_view<R>(
3186        &mut self,
3187        id: EntityId,
3188        f: impl FnOnce(&mut Self) -> R,
3189    ) -> R {
3190        self.rendered_entity_stack.push(id);
3191        let result = f(self);
3192        self.rendered_entity_stack.pop();
3193        result
3194    }
3195
3196    /// Executes the provided function with the specified image cache.
3197    pub fn with_image_cache<F, R>(&mut self, image_cache: Option<AnyImageCache>, f: F) -> R
3198    where
3199        F: FnOnce(&mut Self) -> R,
3200    {
3201        if let Some(image_cache) = image_cache {
3202            self.image_cache_stack.push(image_cache);
3203            let result = f(self);
3204            self.image_cache_stack.pop();
3205            result
3206        } else {
3207            f(self)
3208        }
3209    }
3210
3211    /// Sets an input handler, such as [`ElementInputHandler`][element_input_handler], which interfaces with the
3212    /// platform to receive textual input with proper integration with concerns such
3213    /// as IME interactions. This handler will be active for the upcoming frame until the following frame is
3214    /// rendered.
3215    ///
3216    /// This method should only be called as part of the paint phase of element drawing.
3217    ///
3218    /// [element_input_handler]: crate::ElementInputHandler
3219    pub fn handle_input(
3220        &mut self,
3221        focus_handle: &FocusHandle,
3222        input_handler: impl InputHandler,
3223        cx: &App,
3224    ) {
3225        self.invalidator.debug_assert_paint();
3226
3227        if focus_handle.is_focused(self) {
3228            let cx = self.to_async(cx);
3229            self.next_frame
3230                .input_handlers
3231                .push(Some(PlatformInputHandler::new(cx, Box::new(input_handler))));
3232        }
3233    }
3234
3235    /// Register a mouse event listener on the window for the next frame. The type of event
3236    /// is determined by the first parameter of the given listener. When the next frame is rendered
3237    /// the listener will be cleared.
3238    ///
3239    /// This method should only be called as part of the paint phase of element drawing.
3240    pub fn on_mouse_event<Event: MouseEvent>(
3241        &mut self,
3242        mut handler: impl FnMut(&Event, DispatchPhase, &mut Window, &mut App) + 'static,
3243    ) {
3244        self.invalidator.debug_assert_paint();
3245
3246        self.next_frame.mouse_listeners.push(Some(Box::new(
3247            move |event: &dyn Any, phase: DispatchPhase, window: &mut Window, cx: &mut App| {
3248                if let Some(event) = event.downcast_ref() {
3249                    handler(event, phase, window, cx)
3250                }
3251            },
3252        )));
3253    }
3254
3255    /// Register a key event listener on the window for the next frame. The type of event
3256    /// is determined by the first parameter of the given listener. When the next frame is rendered
3257    /// the listener will be cleared.
3258    ///
3259    /// This is a fairly low-level method, so prefer using event handlers on elements unless you have
3260    /// a specific need to register a global listener.
3261    ///
3262    /// This method should only be called as part of the paint phase of element drawing.
3263    pub fn on_key_event<Event: KeyEvent>(
3264        &mut self,
3265        listener: impl Fn(&Event, DispatchPhase, &mut Window, &mut App) + 'static,
3266    ) {
3267        self.invalidator.debug_assert_paint();
3268
3269        self.next_frame.dispatch_tree.on_key_event(Rc::new(
3270            move |event: &dyn Any, phase, window: &mut Window, cx: &mut App| {
3271                if let Some(event) = event.downcast_ref::<Event>() {
3272                    listener(event, phase, window, cx)
3273                }
3274            },
3275        ));
3276    }
3277
3278    /// Register a modifiers changed event listener on the window for the next frame.
3279    ///
3280    /// This is a fairly low-level method, so prefer using event handlers on elements unless you have
3281    /// a specific need to register a global listener.
3282    ///
3283    /// This method should only be called as part of the paint phase of element drawing.
3284    pub fn on_modifiers_changed(
3285        &mut self,
3286        listener: impl Fn(&ModifiersChangedEvent, &mut Window, &mut App) + 'static,
3287    ) {
3288        self.invalidator.debug_assert_paint();
3289
3290        self.next_frame.dispatch_tree.on_modifiers_changed(Rc::new(
3291            move |event: &ModifiersChangedEvent, window: &mut Window, cx: &mut App| {
3292                listener(event, window, cx)
3293            },
3294        ));
3295    }
3296
3297    /// Register a listener to be called when the given focus handle or one of its descendants receives focus.
3298    /// This does not fire if the given focus handle - or one of its descendants - was previously focused.
3299    /// Returns a subscription and persists until the subscription is dropped.
3300    pub fn on_focus_in(
3301        &mut self,
3302        handle: &FocusHandle,
3303        cx: &mut App,
3304        mut listener: impl FnMut(&mut Window, &mut App) + 'static,
3305    ) -> Subscription {
3306        let focus_id = handle.id;
3307        let (subscription, activate) =
3308            self.new_focus_listener(Box::new(move |event, window, cx| {
3309                if event.is_focus_in(focus_id) {
3310                    listener(window, cx);
3311                }
3312                true
3313            }));
3314        cx.defer(move |_| activate());
3315        subscription
3316    }
3317
3318    /// Register a listener to be called when the given focus handle or one of its descendants loses focus.
3319    /// Returns a subscription and persists until the subscription is dropped.
3320    pub fn on_focus_out(
3321        &mut self,
3322        handle: &FocusHandle,
3323        cx: &mut App,
3324        mut listener: impl FnMut(FocusOutEvent, &mut Window, &mut App) + 'static,
3325    ) -> Subscription {
3326        let focus_id = handle.id;
3327        let (subscription, activate) =
3328            self.new_focus_listener(Box::new(move |event, window, cx| {
3329                if let Some(blurred_id) = event.previous_focus_path.last().copied() {
3330                    if event.is_focus_out(focus_id) {
3331                        let event = FocusOutEvent {
3332                            blurred: WeakFocusHandle {
3333                                id: blurred_id,
3334                                handles: Arc::downgrade(&cx.focus_handles),
3335                            },
3336                        };
3337                        listener(event, window, cx)
3338                    }
3339                }
3340                true
3341            }));
3342        cx.defer(move |_| activate());
3343        subscription
3344    }
3345
3346    fn reset_cursor_style(&self, cx: &mut App) {
3347        // Set the cursor only if we're the active window.
3348        if self.is_window_hovered() {
3349            let style = self
3350                .rendered_frame
3351                .cursor_style(self)
3352                .unwrap_or(CursorStyle::Arrow);
3353            cx.platform.set_cursor_style(style);
3354        }
3355    }
3356
3357    /// Dispatch a given keystroke as though the user had typed it.
3358    /// You can create a keystroke with Keystroke::parse("").
3359    pub fn dispatch_keystroke(&mut self, keystroke: Keystroke, cx: &mut App) -> bool {
3360        let keystroke = keystroke.with_simulated_ime();
3361        let result = self.dispatch_event(
3362            PlatformInput::KeyDown(KeyDownEvent {
3363                keystroke: keystroke.clone(),
3364                is_held: false,
3365            }),
3366            cx,
3367        );
3368        if !result.propagate {
3369            return true;
3370        }
3371
3372        if let Some(input) = keystroke.key_char {
3373            if let Some(mut input_handler) = self.platform_window.take_input_handler() {
3374                input_handler.dispatch_input(&input, self, cx);
3375                self.platform_window.set_input_handler(input_handler);
3376                return true;
3377            }
3378        }
3379
3380        false
3381    }
3382
3383    /// Return a key binding string for an action, to display in the UI. Uses the highest precedence
3384    /// binding for the action (last binding added to the keymap).
3385    pub fn keystroke_text_for(&self, action: &dyn Action) -> String {
3386        self.highest_precedence_binding_for_action(action)
3387            .map(|binding| {
3388                binding
3389                    .keystrokes()
3390                    .iter()
3391                    .map(ToString::to_string)
3392                    .collect::<Vec<_>>()
3393                    .join(" ")
3394            })
3395            .unwrap_or_else(|| action.name().to_string())
3396    }
3397
3398    /// Dispatch a mouse or keyboard event on the window.
3399    #[profiling::function]
3400    pub fn dispatch_event(&mut self, event: PlatformInput, cx: &mut App) -> DispatchEventResult {
3401        self.last_input_timestamp.set(Instant::now());
3402        // Handlers may set this to false by calling `stop_propagation`.
3403        cx.propagate_event = true;
3404        // Handlers may set this to true by calling `prevent_default`.
3405        self.default_prevented = false;
3406
3407        let event = match event {
3408            // Track the mouse position with our own state, since accessing the platform
3409            // API for the mouse position can only occur on the main thread.
3410            PlatformInput::MouseMove(mouse_move) => {
3411                self.mouse_position = mouse_move.position;
3412                self.modifiers = mouse_move.modifiers;
3413                PlatformInput::MouseMove(mouse_move)
3414            }
3415            PlatformInput::MouseDown(mouse_down) => {
3416                self.mouse_position = mouse_down.position;
3417                self.modifiers = mouse_down.modifiers;
3418                PlatformInput::MouseDown(mouse_down)
3419            }
3420            PlatformInput::MouseUp(mouse_up) => {
3421                self.mouse_position = mouse_up.position;
3422                self.modifiers = mouse_up.modifiers;
3423                PlatformInput::MouseUp(mouse_up)
3424            }
3425            PlatformInput::MouseExited(mouse_exited) => {
3426                self.modifiers = mouse_exited.modifiers;
3427                PlatformInput::MouseExited(mouse_exited)
3428            }
3429            PlatformInput::ModifiersChanged(modifiers_changed) => {
3430                self.modifiers = modifiers_changed.modifiers;
3431                self.capslock = modifiers_changed.capslock;
3432                PlatformInput::ModifiersChanged(modifiers_changed)
3433            }
3434            PlatformInput::ScrollWheel(scroll_wheel) => {
3435                self.mouse_position = scroll_wheel.position;
3436                self.modifiers = scroll_wheel.modifiers;
3437                PlatformInput::ScrollWheel(scroll_wheel)
3438            }
3439            // Translate dragging and dropping of external files from the operating system
3440            // to internal drag and drop events.
3441            PlatformInput::FileDrop(file_drop) => match file_drop {
3442                FileDropEvent::Entered { position, paths } => {
3443                    self.mouse_position = position;
3444                    if cx.active_drag.is_none() {
3445                        cx.active_drag = Some(AnyDrag {
3446                            value: Arc::new(paths.clone()),
3447                            view: cx.new(|_| paths).into(),
3448                            cursor_offset: position,
3449                            cursor_style: None,
3450                        });
3451                    }
3452                    PlatformInput::MouseMove(MouseMoveEvent {
3453                        position,
3454                        pressed_button: Some(MouseButton::Left),
3455                        modifiers: Modifiers::default(),
3456                    })
3457                }
3458                FileDropEvent::Pending { position } => {
3459                    self.mouse_position = position;
3460                    PlatformInput::MouseMove(MouseMoveEvent {
3461                        position,
3462                        pressed_button: Some(MouseButton::Left),
3463                        modifiers: Modifiers::default(),
3464                    })
3465                }
3466                FileDropEvent::Submit { position } => {
3467                    cx.activate(true);
3468                    self.mouse_position = position;
3469                    PlatformInput::MouseUp(MouseUpEvent {
3470                        button: MouseButton::Left,
3471                        position,
3472                        modifiers: Modifiers::default(),
3473                        click_count: 1,
3474                    })
3475                }
3476                FileDropEvent::Exited => {
3477                    cx.active_drag.take();
3478                    PlatformInput::FileDrop(FileDropEvent::Exited)
3479                }
3480            },
3481            PlatformInput::KeyDown(_) | PlatformInput::KeyUp(_) => event,
3482        };
3483
3484        if let Some(any_mouse_event) = event.mouse_event() {
3485            self.dispatch_mouse_event(any_mouse_event, cx);
3486        } else if let Some(any_key_event) = event.keyboard_event() {
3487            self.dispatch_key_event(any_key_event, cx);
3488        }
3489
3490        DispatchEventResult {
3491            propagate: cx.propagate_event,
3492            default_prevented: self.default_prevented,
3493        }
3494    }
3495
3496    fn dispatch_mouse_event(&mut self, event: &dyn Any, cx: &mut App) {
3497        let hit_test = self.rendered_frame.hit_test(self.mouse_position());
3498        if hit_test != self.mouse_hit_test {
3499            self.mouse_hit_test = hit_test;
3500            self.reset_cursor_style(cx);
3501        }
3502
3503        #[cfg(any(feature = "inspector", debug_assertions))]
3504        if self.is_inspector_picking(cx) {
3505            self.handle_inspector_mouse_event(event, cx);
3506            // When inspector is picking, all other mouse handling is skipped.
3507            return;
3508        }
3509
3510        let mut mouse_listeners = mem::take(&mut self.rendered_frame.mouse_listeners);
3511
3512        // Capture phase, events bubble from back to front. Handlers for this phase are used for
3513        // special purposes, such as detecting events outside of a given Bounds.
3514        for listener in &mut mouse_listeners {
3515            let listener = listener.as_mut().unwrap();
3516            listener(event, DispatchPhase::Capture, self, cx);
3517            if !cx.propagate_event {
3518                break;
3519            }
3520        }
3521
3522        // Bubble phase, where most normal handlers do their work.
3523        if cx.propagate_event {
3524            for listener in mouse_listeners.iter_mut().rev() {
3525                let listener = listener.as_mut().unwrap();
3526                listener(event, DispatchPhase::Bubble, self, cx);
3527                if !cx.propagate_event {
3528                    break;
3529                }
3530            }
3531        }
3532
3533        self.rendered_frame.mouse_listeners = mouse_listeners;
3534
3535        if cx.has_active_drag() {
3536            if event.is::<MouseMoveEvent>() {
3537                // If this was a mouse move event, redraw the window so that the
3538                // active drag can follow the mouse cursor.
3539                self.refresh();
3540            } else if event.is::<MouseUpEvent>() {
3541                // If this was a mouse up event, cancel the active drag and redraw
3542                // the window.
3543                cx.active_drag = None;
3544                self.refresh();
3545            }
3546        }
3547    }
3548
3549    fn dispatch_key_event(&mut self, event: &dyn Any, cx: &mut App) {
3550        if self.invalidator.is_dirty() {
3551            self.draw(cx).clear();
3552        }
3553
3554        let node_id = self.focus_node_id_in_rendered_frame(self.focus);
3555        let dispatch_path = self.rendered_frame.dispatch_tree.dispatch_path(node_id);
3556
3557        let mut keystroke: Option<Keystroke> = None;
3558
3559        if let Some(event) = event.downcast_ref::<ModifiersChangedEvent>() {
3560            if event.modifiers.number_of_modifiers() == 0
3561                && self.pending_modifier.modifiers.number_of_modifiers() == 1
3562                && !self.pending_modifier.saw_keystroke
3563            {
3564                let key = match self.pending_modifier.modifiers {
3565                    modifiers if modifiers.shift => Some("shift"),
3566                    modifiers if modifiers.control => Some("control"),
3567                    modifiers if modifiers.alt => Some("alt"),
3568                    modifiers if modifiers.platform => Some("platform"),
3569                    modifiers if modifiers.function => Some("function"),
3570                    _ => None,
3571                };
3572                if let Some(key) = key {
3573                    keystroke = Some(Keystroke {
3574                        key: key.to_string(),
3575                        key_char: None,
3576                        modifiers: Modifiers::default(),
3577                    });
3578                }
3579            }
3580
3581            if self.pending_modifier.modifiers.number_of_modifiers() == 0
3582                && event.modifiers.number_of_modifiers() == 1
3583            {
3584                self.pending_modifier.saw_keystroke = false
3585            }
3586            self.pending_modifier.modifiers = event.modifiers
3587        } else if let Some(key_down_event) = event.downcast_ref::<KeyDownEvent>() {
3588            self.pending_modifier.saw_keystroke = true;
3589            keystroke = Some(key_down_event.keystroke.clone());
3590        }
3591
3592        let Some(keystroke) = keystroke else {
3593            self.finish_dispatch_key_event(event, dispatch_path, self.context_stack(), cx);
3594            return;
3595        };
3596
3597        cx.propagate_event = true;
3598        self.dispatch_keystroke_interceptors(event, self.context_stack(), cx);
3599        if !cx.propagate_event {
3600            self.finish_dispatch_key_event(event, dispatch_path, self.context_stack(), cx);
3601            return;
3602        }
3603
3604        let mut currently_pending = self.pending_input.take().unwrap_or_default();
3605        if currently_pending.focus.is_some() && currently_pending.focus != self.focus {
3606            currently_pending = PendingInput::default();
3607        }
3608
3609        let match_result = self.rendered_frame.dispatch_tree.dispatch_key(
3610            currently_pending.keystrokes,
3611            keystroke,
3612            &dispatch_path,
3613        );
3614
3615        if !match_result.to_replay.is_empty() {
3616            self.replay_pending_input(match_result.to_replay, cx)
3617        }
3618
3619        if !match_result.pending.is_empty() {
3620            currently_pending.keystrokes = match_result.pending;
3621            currently_pending.focus = self.focus;
3622            currently_pending.timer = Some(self.spawn(cx, async move |cx| {
3623                cx.background_executor.timer(Duration::from_secs(1)).await;
3624                cx.update(move |window, cx| {
3625                    let Some(currently_pending) = window
3626                        .pending_input
3627                        .take()
3628                        .filter(|pending| pending.focus == window.focus)
3629                    else {
3630                        return;
3631                    };
3632
3633                    let node_id = window.focus_node_id_in_rendered_frame(window.focus);
3634                    let dispatch_path = window.rendered_frame.dispatch_tree.dispatch_path(node_id);
3635
3636                    let to_replay = window
3637                        .rendered_frame
3638                        .dispatch_tree
3639                        .flush_dispatch(currently_pending.keystrokes, &dispatch_path);
3640
3641                    window.pending_input_changed(cx);
3642                    window.replay_pending_input(to_replay, cx)
3643                })
3644                .log_err();
3645            }));
3646            self.pending_input = Some(currently_pending);
3647            self.pending_input_changed(cx);
3648            cx.propagate_event = false;
3649            return;
3650        }
3651
3652        for binding in match_result.bindings {
3653            self.dispatch_action_on_node(node_id, binding.action.as_ref(), cx);
3654            if !cx.propagate_event {
3655                self.dispatch_keystroke_observers(
3656                    event,
3657                    Some(binding.action),
3658                    match_result.context_stack.clone(),
3659                    cx,
3660                );
3661                self.pending_input_changed(cx);
3662                return;
3663            }
3664        }
3665
3666        self.finish_dispatch_key_event(event, dispatch_path, match_result.context_stack, cx);
3667        self.pending_input_changed(cx);
3668    }
3669
3670    fn finish_dispatch_key_event(
3671        &mut self,
3672        event: &dyn Any,
3673        dispatch_path: SmallVec<[DispatchNodeId; 32]>,
3674        context_stack: Vec<KeyContext>,
3675        cx: &mut App,
3676    ) {
3677        self.dispatch_key_down_up_event(event, &dispatch_path, cx);
3678        if !cx.propagate_event {
3679            return;
3680        }
3681
3682        self.dispatch_modifiers_changed_event(event, &dispatch_path, cx);
3683        if !cx.propagate_event {
3684            return;
3685        }
3686
3687        self.dispatch_keystroke_observers(event, None, context_stack, cx);
3688    }
3689
3690    fn pending_input_changed(&mut self, cx: &mut App) {
3691        self.pending_input_observers
3692            .clone()
3693            .retain(&(), |callback| callback(self, cx));
3694    }
3695
3696    fn dispatch_key_down_up_event(
3697        &mut self,
3698        event: &dyn Any,
3699        dispatch_path: &SmallVec<[DispatchNodeId; 32]>,
3700        cx: &mut App,
3701    ) {
3702        // Capture phase
3703        for node_id in dispatch_path {
3704            let node = self.rendered_frame.dispatch_tree.node(*node_id);
3705
3706            for key_listener in node.key_listeners.clone() {
3707                key_listener(event, DispatchPhase::Capture, self, cx);
3708                if !cx.propagate_event {
3709                    return;
3710                }
3711            }
3712        }
3713
3714        // Bubble phase
3715        for node_id in dispatch_path.iter().rev() {
3716            // Handle low level key events
3717            let node = self.rendered_frame.dispatch_tree.node(*node_id);
3718            for key_listener in node.key_listeners.clone() {
3719                key_listener(event, DispatchPhase::Bubble, self, cx);
3720                if !cx.propagate_event {
3721                    return;
3722                }
3723            }
3724        }
3725    }
3726
3727    fn dispatch_modifiers_changed_event(
3728        &mut self,
3729        event: &dyn Any,
3730        dispatch_path: &SmallVec<[DispatchNodeId; 32]>,
3731        cx: &mut App,
3732    ) {
3733        let Some(event) = event.downcast_ref::<ModifiersChangedEvent>() else {
3734            return;
3735        };
3736        for node_id in dispatch_path.iter().rev() {
3737            let node = self.rendered_frame.dispatch_tree.node(*node_id);
3738            for listener in node.modifiers_changed_listeners.clone() {
3739                listener(event, self, cx);
3740                if !cx.propagate_event {
3741                    return;
3742                }
3743            }
3744        }
3745    }
3746
3747    /// Determine whether a potential multi-stroke key binding is in progress on this window.
3748    pub fn has_pending_keystrokes(&self) -> bool {
3749        self.pending_input.is_some()
3750    }
3751
3752    pub(crate) fn clear_pending_keystrokes(&mut self) {
3753        self.pending_input.take();
3754    }
3755
3756    /// Returns the currently pending input keystrokes that might result in a multi-stroke key binding.
3757    pub fn pending_input_keystrokes(&self) -> Option<&[Keystroke]> {
3758        self.pending_input
3759            .as_ref()
3760            .map(|pending_input| pending_input.keystrokes.as_slice())
3761    }
3762
3763    fn replay_pending_input(&mut self, replays: SmallVec<[Replay; 1]>, cx: &mut App) {
3764        let node_id = self.focus_node_id_in_rendered_frame(self.focus);
3765        let dispatch_path = self.rendered_frame.dispatch_tree.dispatch_path(node_id);
3766
3767        'replay: for replay in replays {
3768            let event = KeyDownEvent {
3769                keystroke: replay.keystroke.clone(),
3770                is_held: false,
3771            };
3772
3773            cx.propagate_event = true;
3774            for binding in replay.bindings {
3775                self.dispatch_action_on_node(node_id, binding.action.as_ref(), cx);
3776                if !cx.propagate_event {
3777                    self.dispatch_keystroke_observers(
3778                        &event,
3779                        Some(binding.action),
3780                        Vec::default(),
3781                        cx,
3782                    );
3783                    continue 'replay;
3784                }
3785            }
3786
3787            self.dispatch_key_down_up_event(&event, &dispatch_path, cx);
3788            if !cx.propagate_event {
3789                continue 'replay;
3790            }
3791            if let Some(input) = replay.keystroke.key_char.as_ref().cloned() {
3792                if let Some(mut input_handler) = self.platform_window.take_input_handler() {
3793                    input_handler.dispatch_input(&input, self, cx);
3794                    self.platform_window.set_input_handler(input_handler)
3795                }
3796            }
3797        }
3798    }
3799
3800    fn focus_node_id_in_rendered_frame(&self, focus_id: Option<FocusId>) -> DispatchNodeId {
3801        focus_id
3802            .and_then(|focus_id| {
3803                self.rendered_frame
3804                    .dispatch_tree
3805                    .focusable_node_id(focus_id)
3806            })
3807            .unwrap_or_else(|| self.rendered_frame.dispatch_tree.root_node_id())
3808    }
3809
3810    fn dispatch_action_on_node(
3811        &mut self,
3812        node_id: DispatchNodeId,
3813        action: &dyn Action,
3814        cx: &mut App,
3815    ) {
3816        let dispatch_path = self.rendered_frame.dispatch_tree.dispatch_path(node_id);
3817
3818        // Capture phase for global actions.
3819        cx.propagate_event = true;
3820        if let Some(mut global_listeners) = cx
3821            .global_action_listeners
3822            .remove(&action.as_any().type_id())
3823        {
3824            for listener in &global_listeners {
3825                listener(action.as_any(), DispatchPhase::Capture, cx);
3826                if !cx.propagate_event {
3827                    break;
3828                }
3829            }
3830
3831            global_listeners.extend(
3832                cx.global_action_listeners
3833                    .remove(&action.as_any().type_id())
3834                    .unwrap_or_default(),
3835            );
3836
3837            cx.global_action_listeners
3838                .insert(action.as_any().type_id(), global_listeners);
3839        }
3840
3841        if !cx.propagate_event {
3842            return;
3843        }
3844
3845        // Capture phase for window actions.
3846        for node_id in &dispatch_path {
3847            let node = self.rendered_frame.dispatch_tree.node(*node_id);
3848            for DispatchActionListener {
3849                action_type,
3850                listener,
3851            } in node.action_listeners.clone()
3852            {
3853                let any_action = action.as_any();
3854                if action_type == any_action.type_id() {
3855                    listener(any_action, DispatchPhase::Capture, self, cx);
3856
3857                    if !cx.propagate_event {
3858                        return;
3859                    }
3860                }
3861            }
3862        }
3863
3864        // Bubble phase for window actions.
3865        for node_id in dispatch_path.iter().rev() {
3866            let node = self.rendered_frame.dispatch_tree.node(*node_id);
3867            for DispatchActionListener {
3868                action_type,
3869                listener,
3870            } in node.action_listeners.clone()
3871            {
3872                let any_action = action.as_any();
3873                if action_type == any_action.type_id() {
3874                    cx.propagate_event = false; // Actions stop propagation by default during the bubble phase
3875                    listener(any_action, DispatchPhase::Bubble, self, cx);
3876
3877                    if !cx.propagate_event {
3878                        return;
3879                    }
3880                }
3881            }
3882        }
3883
3884        // Bubble phase for global actions.
3885        if let Some(mut global_listeners) = cx
3886            .global_action_listeners
3887            .remove(&action.as_any().type_id())
3888        {
3889            for listener in global_listeners.iter().rev() {
3890                cx.propagate_event = false; // Actions stop propagation by default during the bubble phase
3891
3892                listener(action.as_any(), DispatchPhase::Bubble, cx);
3893                if !cx.propagate_event {
3894                    break;
3895                }
3896            }
3897
3898            global_listeners.extend(
3899                cx.global_action_listeners
3900                    .remove(&action.as_any().type_id())
3901                    .unwrap_or_default(),
3902            );
3903
3904            cx.global_action_listeners
3905                .insert(action.as_any().type_id(), global_listeners);
3906        }
3907    }
3908
3909    /// Register the given handler to be invoked whenever the global of the given type
3910    /// is updated.
3911    pub fn observe_global<G: Global>(
3912        &mut self,
3913        cx: &mut App,
3914        f: impl Fn(&mut Window, &mut App) + 'static,
3915    ) -> Subscription {
3916        let window_handle = self.handle;
3917        let (subscription, activate) = cx.global_observers.insert(
3918            TypeId::of::<G>(),
3919            Box::new(move |cx| {
3920                window_handle
3921                    .update(cx, |_, window, cx| f(window, cx))
3922                    .is_ok()
3923            }),
3924        );
3925        cx.defer(move |_| activate());
3926        subscription
3927    }
3928
3929    /// Focus the current window and bring it to the foreground at the platform level.
3930    pub fn activate_window(&self) {
3931        self.platform_window.activate();
3932    }
3933
3934    /// Minimize the current window at the platform level.
3935    pub fn minimize_window(&self) {
3936        self.platform_window.minimize();
3937    }
3938
3939    /// Toggle full screen status on the current window at the platform level.
3940    pub fn toggle_fullscreen(&self) {
3941        self.platform_window.toggle_fullscreen();
3942    }
3943
3944    /// Updates the IME panel position suggestions for languages like japanese, chinese.
3945    pub fn invalidate_character_coordinates(&self) {
3946        self.on_next_frame(|window, cx| {
3947            if let Some(mut input_handler) = window.platform_window.take_input_handler() {
3948                if let Some(bounds) = input_handler.selected_bounds(window, cx) {
3949                    window
3950                        .platform_window
3951                        .update_ime_position(bounds.scale(window.scale_factor()));
3952                }
3953                window.platform_window.set_input_handler(input_handler);
3954            }
3955        });
3956    }
3957
3958    /// Present a platform dialog.
3959    /// The provided message will be presented, along with buttons for each answer.
3960    /// When a button is clicked, the returned Receiver will receive the index of the clicked button.
3961    pub fn prompt<T>(
3962        &mut self,
3963        level: PromptLevel,
3964        message: &str,
3965        detail: Option<&str>,
3966        answers: &[T],
3967        cx: &mut App,
3968    ) -> oneshot::Receiver<usize>
3969    where
3970        T: Clone + Into<PromptButton>,
3971    {
3972        let prompt_builder = cx.prompt_builder.take();
3973        let Some(prompt_builder) = prompt_builder else {
3974            unreachable!("Re-entrant window prompting is not supported by GPUI");
3975        };
3976
3977        let answers = answers
3978            .iter()
3979            .map(|answer| answer.clone().into())
3980            .collect::<Vec<_>>();
3981
3982        let receiver = match &prompt_builder {
3983            PromptBuilder::Default => self
3984                .platform_window
3985                .prompt(level, message, detail, &answers)
3986                .unwrap_or_else(|| {
3987                    self.build_custom_prompt(&prompt_builder, level, message, detail, &answers, cx)
3988                }),
3989            PromptBuilder::Custom(_) => {
3990                self.build_custom_prompt(&prompt_builder, level, message, detail, &answers, cx)
3991            }
3992        };
3993
3994        cx.prompt_builder = Some(prompt_builder);
3995
3996        receiver
3997    }
3998
3999    fn build_custom_prompt(
4000        &mut self,
4001        prompt_builder: &PromptBuilder,
4002        level: PromptLevel,
4003        message: &str,
4004        detail: Option<&str>,
4005        answers: &[PromptButton],
4006        cx: &mut App,
4007    ) -> oneshot::Receiver<usize> {
4008        let (sender, receiver) = oneshot::channel();
4009        let handle = PromptHandle::new(sender);
4010        let handle = (prompt_builder)(level, message, detail, answers, handle, self, cx);
4011        self.prompt = Some(handle);
4012        receiver
4013    }
4014
4015    /// Returns the current context stack.
4016    pub fn context_stack(&self) -> Vec<KeyContext> {
4017        let node_id = self.focus_node_id_in_rendered_frame(self.focus);
4018        let dispatch_tree = &self.rendered_frame.dispatch_tree;
4019        dispatch_tree
4020            .dispatch_path(node_id)
4021            .iter()
4022            .filter_map(move |&node_id| dispatch_tree.node(node_id).context.clone())
4023            .collect()
4024    }
4025
4026    /// Returns all available actions for the focused element.
4027    pub fn available_actions(&self, cx: &App) -> Vec<Box<dyn Action>> {
4028        let node_id = self.focus_node_id_in_rendered_frame(self.focus);
4029        let mut actions = self.rendered_frame.dispatch_tree.available_actions(node_id);
4030        for action_type in cx.global_action_listeners.keys() {
4031            if let Err(ix) = actions.binary_search_by_key(action_type, |a| a.as_any().type_id()) {
4032                let action = cx.actions.build_action_type(action_type).ok();
4033                if let Some(action) = action {
4034                    actions.insert(ix, action);
4035                }
4036            }
4037        }
4038        actions
4039    }
4040
4041    /// Returns key bindings that invoke an action on the currently focused element. Bindings are
4042    /// returned in the order they were added. For display, the last binding should take precedence.
4043    pub fn bindings_for_action(&self, action: &dyn Action) -> Vec<KeyBinding> {
4044        self.rendered_frame
4045            .dispatch_tree
4046            .bindings_for_action(action, &self.rendered_frame.dispatch_tree.context_stack)
4047    }
4048
4049    /// Returns the highest precedence key binding that invokes an action on the currently focused
4050    /// element. This is more efficient than getting the last result of `bindings_for_action`.
4051    pub fn highest_precedence_binding_for_action(&self, action: &dyn Action) -> Option<KeyBinding> {
4052        self.rendered_frame
4053            .dispatch_tree
4054            .highest_precedence_binding_for_action(
4055                action,
4056                &self.rendered_frame.dispatch_tree.context_stack,
4057            )
4058    }
4059
4060    /// Returns the key bindings for an action in a context.
4061    pub fn bindings_for_action_in_context(
4062        &self,
4063        action: &dyn Action,
4064        context: KeyContext,
4065    ) -> Vec<KeyBinding> {
4066        let dispatch_tree = &self.rendered_frame.dispatch_tree;
4067        dispatch_tree.bindings_for_action(action, &[context])
4068    }
4069
4070    /// Returns the highest precedence key binding for an action in a context. This is more
4071    /// efficient than getting the last result of `bindings_for_action_in_context`.
4072    pub fn highest_precedence_binding_for_action_in_context(
4073        &self,
4074        action: &dyn Action,
4075        context: KeyContext,
4076    ) -> Option<KeyBinding> {
4077        let dispatch_tree = &self.rendered_frame.dispatch_tree;
4078        dispatch_tree.highest_precedence_binding_for_action(action, &[context])
4079    }
4080
4081    /// Returns any bindings that would invoke an action on the given focus handle if it were
4082    /// focused. Bindings are returned in the order they were added. For display, the last binding
4083    /// should take precedence.
4084    pub fn bindings_for_action_in(
4085        &self,
4086        action: &dyn Action,
4087        focus_handle: &FocusHandle,
4088    ) -> Vec<KeyBinding> {
4089        let dispatch_tree = &self.rendered_frame.dispatch_tree;
4090        let Some(context_stack) = self.context_stack_for_focus_handle(focus_handle) else {
4091            return vec![];
4092        };
4093        dispatch_tree.bindings_for_action(action, &context_stack)
4094    }
4095
4096    /// Returns the highest precedence key binding that would invoke an action on the given focus
4097    /// handle if it were focused. This is more efficient than getting the last result of
4098    /// `bindings_for_action_in`.
4099    pub fn highest_precedence_binding_for_action_in(
4100        &self,
4101        action: &dyn Action,
4102        focus_handle: &FocusHandle,
4103    ) -> Option<KeyBinding> {
4104        let dispatch_tree = &self.rendered_frame.dispatch_tree;
4105        let context_stack = self.context_stack_for_focus_handle(focus_handle)?;
4106        dispatch_tree.highest_precedence_binding_for_action(action, &context_stack)
4107    }
4108
4109    fn context_stack_for_focus_handle(
4110        &self,
4111        focus_handle: &FocusHandle,
4112    ) -> Option<Vec<KeyContext>> {
4113        let dispatch_tree = &self.rendered_frame.dispatch_tree;
4114        let node_id = dispatch_tree.focusable_node_id(focus_handle.id)?;
4115        let context_stack: Vec<_> = dispatch_tree
4116            .dispatch_path(node_id)
4117            .into_iter()
4118            .filter_map(|node_id| dispatch_tree.node(node_id).context.clone())
4119            .collect();
4120        Some(context_stack)
4121    }
4122
4123    /// Returns a generic event listener that invokes the given listener with the view and context associated with the given view handle.
4124    pub fn listener_for<V: Render, E>(
4125        &self,
4126        view: &Entity<V>,
4127        f: impl Fn(&mut V, &E, &mut Window, &mut Context<V>) + 'static,
4128    ) -> impl Fn(&E, &mut Window, &mut App) + 'static {
4129        let view = view.downgrade();
4130        move |e: &E, window: &mut Window, cx: &mut App| {
4131            view.update(cx, |view, cx| f(view, e, window, cx)).ok();
4132        }
4133    }
4134
4135    /// Returns a generic handler that invokes the given handler with the view and context associated with the given view handle.
4136    pub fn handler_for<V: Render, Callback: Fn(&mut V, &mut Window, &mut Context<V>) + 'static>(
4137        &self,
4138        view: &Entity<V>,
4139        f: Callback,
4140    ) -> impl Fn(&mut Window, &mut App) + use<V, Callback> {
4141        let view = view.downgrade();
4142        move |window: &mut Window, cx: &mut App| {
4143            view.update(cx, |view, cx| f(view, window, cx)).ok();
4144        }
4145    }
4146
4147    /// Register a callback that can interrupt the closing of the current window based the returned boolean.
4148    /// If the callback returns false, the window won't be closed.
4149    pub fn on_window_should_close(
4150        &self,
4151        cx: &App,
4152        f: impl Fn(&mut Window, &mut App) -> bool + 'static,
4153    ) {
4154        let mut cx = self.to_async(cx);
4155        self.platform_window.on_should_close(Box::new(move || {
4156            cx.update(|window, cx| f(window, cx)).unwrap_or(true)
4157        }))
4158    }
4159
4160    /// Register an action listener on the window for the next frame. The type of action
4161    /// is determined by the first parameter of the given listener. When the next frame is rendered
4162    /// the listener will be cleared.
4163    ///
4164    /// This is a fairly low-level method, so prefer using action handlers on elements unless you have
4165    /// a specific need to register a global listener.
4166    pub fn on_action(
4167        &mut self,
4168        action_type: TypeId,
4169        listener: impl Fn(&dyn Any, DispatchPhase, &mut Window, &mut App) + 'static,
4170    ) {
4171        self.next_frame
4172            .dispatch_tree
4173            .on_action(action_type, Rc::new(listener));
4174    }
4175
4176    /// Read information about the GPU backing this window.
4177    /// Currently returns None on Mac and Windows.
4178    pub fn gpu_specs(&self) -> Option<GpuSpecs> {
4179        self.platform_window.gpu_specs()
4180    }
4181
4182    /// Perform titlebar double-click action.
4183    /// This is MacOS specific.
4184    pub fn titlebar_double_click(&self) {
4185        self.platform_window.titlebar_double_click();
4186    }
4187
4188    /// Toggles the inspector mode on this window.
4189    #[cfg(any(feature = "inspector", debug_assertions))]
4190    pub fn toggle_inspector(&mut self, cx: &mut App) {
4191        self.inspector = match self.inspector {
4192            None => Some(cx.new(|_| Inspector::new())),
4193            Some(_) => None,
4194        };
4195        self.refresh();
4196    }
4197
4198    /// Returns true if the window is in inspector mode.
4199    pub fn is_inspector_picking(&self, _cx: &App) -> bool {
4200        #[cfg(any(feature = "inspector", debug_assertions))]
4201        {
4202            if let Some(inspector) = &self.inspector {
4203                return inspector.read(_cx).is_picking();
4204            }
4205        }
4206        false
4207    }
4208
4209    /// Executes the provided function with mutable access to an inspector state.
4210    #[cfg(any(feature = "inspector", debug_assertions))]
4211    pub fn with_inspector_state<T: 'static, R>(
4212        &mut self,
4213        _inspector_id: Option<&crate::InspectorElementId>,
4214        cx: &mut App,
4215        f: impl FnOnce(&mut Option<T>, &mut Self) -> R,
4216    ) -> R {
4217        if let Some(inspector_id) = _inspector_id {
4218            if let Some(inspector) = &self.inspector {
4219                let inspector = inspector.clone();
4220                let active_element_id = inspector.read(cx).active_element_id();
4221                if Some(inspector_id) == active_element_id {
4222                    return inspector.update(cx, |inspector, _cx| {
4223                        inspector.with_active_element_state(self, f)
4224                    });
4225                }
4226            }
4227        }
4228        f(&mut None, self)
4229    }
4230
4231    #[cfg(any(feature = "inspector", debug_assertions))]
4232    pub(crate) fn build_inspector_element_id(
4233        &mut self,
4234        path: crate::InspectorElementPath,
4235    ) -> crate::InspectorElementId {
4236        self.invalidator.debug_assert_paint_or_prepaint();
4237        let path = Rc::new(path);
4238        let next_instance_id = self
4239            .next_frame
4240            .next_inspector_instance_ids
4241            .entry(path.clone())
4242            .or_insert(0);
4243        let instance_id = *next_instance_id;
4244        *next_instance_id += 1;
4245        crate::InspectorElementId { path, instance_id }
4246    }
4247
4248    #[cfg(any(feature = "inspector", debug_assertions))]
4249    fn prepaint_inspector(&mut self, inspector_width: Pixels, cx: &mut App) -> Option<AnyElement> {
4250        if let Some(inspector) = self.inspector.take() {
4251            let mut inspector_element = AnyView::from(inspector.clone()).into_any_element();
4252            inspector_element.prepaint_as_root(
4253                point(self.viewport_size.width - inspector_width, px(0.0)),
4254                size(inspector_width, self.viewport_size.height).into(),
4255                self,
4256                cx,
4257            );
4258            self.inspector = Some(inspector);
4259            Some(inspector_element)
4260        } else {
4261            None
4262        }
4263    }
4264
4265    #[cfg(any(feature = "inspector", debug_assertions))]
4266    fn paint_inspector(&mut self, mut inspector_element: Option<AnyElement>, cx: &mut App) {
4267        if let Some(mut inspector_element) = inspector_element {
4268            inspector_element.paint(self, cx);
4269        };
4270    }
4271
4272    /// Registers a hitbox that can be used for inspector picking mode, allowing users to select and
4273    /// inspect UI elements by clicking on them.
4274    #[cfg(any(feature = "inspector", debug_assertions))]
4275    pub fn insert_inspector_hitbox(
4276        &mut self,
4277        hitbox_id: HitboxId,
4278        inspector_id: Option<&crate::InspectorElementId>,
4279        cx: &App,
4280    ) {
4281        self.invalidator.debug_assert_paint_or_prepaint();
4282        if !self.is_inspector_picking(cx) {
4283            return;
4284        }
4285        if let Some(inspector_id) = inspector_id {
4286            self.next_frame
4287                .inspector_hitboxes
4288                .insert(hitbox_id, inspector_id.clone());
4289        }
4290    }
4291
4292    #[cfg(any(feature = "inspector", debug_assertions))]
4293    fn paint_inspector_hitbox(&mut self, cx: &App) {
4294        if let Some(inspector) = self.inspector.as_ref() {
4295            let inspector = inspector.read(cx);
4296            if let Some((hitbox_id, _)) = self.hovered_inspector_hitbox(inspector, &self.next_frame)
4297            {
4298                if let Some(hitbox) = self
4299                    .next_frame
4300                    .hitboxes
4301                    .iter()
4302                    .find(|hitbox| hitbox.id == hitbox_id)
4303                {
4304                    self.paint_quad(crate::fill(hitbox.bounds, crate::rgba(0x61afef4d)));
4305                }
4306            }
4307        }
4308    }
4309
4310    #[cfg(any(feature = "inspector", debug_assertions))]
4311    fn handle_inspector_mouse_event(&mut self, event: &dyn Any, cx: &mut App) {
4312        let Some(inspector) = self.inspector.clone() else {
4313            return;
4314        };
4315        if event.downcast_ref::<MouseMoveEvent>().is_some() {
4316            inspector.update(cx, |inspector, _cx| {
4317                if let Some((_, inspector_id)) =
4318                    self.hovered_inspector_hitbox(inspector, &self.rendered_frame)
4319                {
4320                    inspector.hover(inspector_id, self);
4321                }
4322            });
4323        } else if event.downcast_ref::<crate::MouseDownEvent>().is_some() {
4324            inspector.update(cx, |inspector, _cx| {
4325                if let Some((_, inspector_id)) =
4326                    self.hovered_inspector_hitbox(inspector, &self.rendered_frame)
4327                {
4328                    inspector.select(inspector_id, self);
4329                }
4330            });
4331        } else if let Some(event) = event.downcast_ref::<crate::ScrollWheelEvent>() {
4332            // This should be kept in sync with SCROLL_LINES in x11 platform.
4333            const SCROLL_LINES: f32 = 3.0;
4334            const SCROLL_PIXELS_PER_LAYER: f32 = 36.0;
4335            let delta_y = event
4336                .delta
4337                .pixel_delta(px(SCROLL_PIXELS_PER_LAYER / SCROLL_LINES))
4338                .y;
4339            if let Some(inspector) = self.inspector.clone() {
4340                inspector.update(cx, |inspector, _cx| {
4341                    if let Some(depth) = inspector.pick_depth.as_mut() {
4342                        *depth += delta_y.0 / SCROLL_PIXELS_PER_LAYER;
4343                        let max_depth = self.mouse_hit_test.ids.len() as f32 - 0.5;
4344                        if *depth < 0.0 {
4345                            *depth = 0.0;
4346                        } else if *depth > max_depth {
4347                            *depth = max_depth;
4348                        }
4349                        if let Some((_, inspector_id)) =
4350                            self.hovered_inspector_hitbox(inspector, &self.rendered_frame)
4351                        {
4352                            inspector.set_active_element_id(inspector_id.clone(), self);
4353                        }
4354                    }
4355                });
4356            }
4357        }
4358    }
4359
4360    #[cfg(any(feature = "inspector", debug_assertions))]
4361    fn hovered_inspector_hitbox(
4362        &self,
4363        inspector: &Inspector,
4364        frame: &Frame,
4365    ) -> Option<(HitboxId, crate::InspectorElementId)> {
4366        if let Some(pick_depth) = inspector.pick_depth {
4367            let depth = (pick_depth as i64).try_into().unwrap_or(0);
4368            let max_skipped = self.mouse_hit_test.ids.len().saturating_sub(1);
4369            let skip_count = (depth as usize).min(max_skipped);
4370            for hitbox_id in self.mouse_hit_test.ids.iter().skip(skip_count) {
4371                if let Some(inspector_id) = frame.inspector_hitboxes.get(hitbox_id) {
4372                    return Some((*hitbox_id, inspector_id.clone()));
4373                }
4374            }
4375        }
4376        return None;
4377    }
4378}
4379
4380// #[derive(Clone, Copy, Eq, PartialEq, Hash)]
4381slotmap::new_key_type! {
4382    /// A unique identifier for a window.
4383    pub struct WindowId;
4384}
4385
4386impl WindowId {
4387    /// Converts this window ID to a `u64`.
4388    pub fn as_u64(&self) -> u64 {
4389        self.0.as_ffi()
4390    }
4391}
4392
4393impl From<u64> for WindowId {
4394    fn from(value: u64) -> Self {
4395        WindowId(slotmap::KeyData::from_ffi(value))
4396    }
4397}
4398
4399/// A handle to a window with a specific root view type.
4400/// Note that this does not keep the window alive on its own.
4401#[derive(Deref, DerefMut)]
4402pub struct WindowHandle<V> {
4403    #[deref]
4404    #[deref_mut]
4405    pub(crate) any_handle: AnyWindowHandle,
4406    state_type: PhantomData<V>,
4407}
4408
4409impl<V: 'static + Render> WindowHandle<V> {
4410    /// Creates a new handle from a window ID.
4411    /// This does not check if the root type of the window is `V`.
4412    pub fn new(id: WindowId) -> Self {
4413        WindowHandle {
4414            any_handle: AnyWindowHandle {
4415                id,
4416                state_type: TypeId::of::<V>(),
4417            },
4418            state_type: PhantomData,
4419        }
4420    }
4421
4422    /// Get the root view out of this window.
4423    ///
4424    /// This will fail if the window is closed or if the root view's type does not match `V`.
4425    #[cfg(any(test, feature = "test-support"))]
4426    pub fn root<C>(&self, cx: &mut C) -> Result<Entity<V>>
4427    where
4428        C: AppContext,
4429    {
4430        crate::Flatten::flatten(cx.update_window(self.any_handle, |root_view, _, _| {
4431            root_view
4432                .downcast::<V>()
4433                .map_err(|_| anyhow!("the type of the window's root view has changed"))
4434        }))
4435    }
4436
4437    /// Updates the root view of this window.
4438    ///
4439    /// This will fail if the window has been closed or if the root view's type does not match
4440    pub fn update<C, R>(
4441        &self,
4442        cx: &mut C,
4443        update: impl FnOnce(&mut V, &mut Window, &mut Context<V>) -> R,
4444    ) -> Result<R>
4445    where
4446        C: AppContext,
4447    {
4448        cx.update_window(self.any_handle, |root_view, window, cx| {
4449            let view = root_view
4450                .downcast::<V>()
4451                .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
4452
4453            Ok(view.update(cx, |view, cx| update(view, window, cx)))
4454        })?
4455    }
4456
4457    /// Read the root view out of this window.
4458    ///
4459    /// This will fail if the window is closed or if the root view's type does not match `V`.
4460    pub fn read<'a>(&self, cx: &'a App) -> Result<&'a V> {
4461        let x = cx
4462            .windows
4463            .get(self.id)
4464            .and_then(|window| {
4465                window
4466                    .as_ref()
4467                    .and_then(|window| window.root.clone())
4468                    .map(|root_view| root_view.downcast::<V>())
4469            })
4470            .context("window not found")?
4471            .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
4472
4473        Ok(x.read(cx))
4474    }
4475
4476    /// Read the root view out of this window, with a callback
4477    ///
4478    /// This will fail if the window is closed or if the root view's type does not match `V`.
4479    pub fn read_with<C, R>(&self, cx: &C, read_with: impl FnOnce(&V, &App) -> R) -> Result<R>
4480    where
4481        C: AppContext,
4482    {
4483        cx.read_window(self, |root_view, cx| read_with(root_view.read(cx), cx))
4484    }
4485
4486    /// Read the root view pointer off of this window.
4487    ///
4488    /// This will fail if the window is closed or if the root view's type does not match `V`.
4489    pub fn entity<C>(&self, cx: &C) -> Result<Entity<V>>
4490    where
4491        C: AppContext,
4492    {
4493        cx.read_window(self, |root_view, _cx| root_view.clone())
4494    }
4495
4496    /// Check if this window is 'active'.
4497    ///
4498    /// Will return `None` if the window is closed or currently
4499    /// borrowed.
4500    pub fn is_active(&self, cx: &mut App) -> Option<bool> {
4501        cx.update_window(self.any_handle, |_, window, _| window.is_window_active())
4502            .ok()
4503    }
4504}
4505
4506impl<V> Copy for WindowHandle<V> {}
4507
4508impl<V> Clone for WindowHandle<V> {
4509    fn clone(&self) -> Self {
4510        *self
4511    }
4512}
4513
4514impl<V> PartialEq for WindowHandle<V> {
4515    fn eq(&self, other: &Self) -> bool {
4516        self.any_handle == other.any_handle
4517    }
4518}
4519
4520impl<V> Eq for WindowHandle<V> {}
4521
4522impl<V> Hash for WindowHandle<V> {
4523    fn hash<H: Hasher>(&self, state: &mut H) {
4524        self.any_handle.hash(state);
4525    }
4526}
4527
4528impl<V: 'static> From<WindowHandle<V>> for AnyWindowHandle {
4529    fn from(val: WindowHandle<V>) -> Self {
4530        val.any_handle
4531    }
4532}
4533
4534unsafe impl<V> Send for WindowHandle<V> {}
4535unsafe impl<V> Sync for WindowHandle<V> {}
4536
4537/// A handle to a window with any root view type, which can be downcast to a window with a specific root view type.
4538#[derive(Copy, Clone, PartialEq, Eq, Hash)]
4539pub struct AnyWindowHandle {
4540    pub(crate) id: WindowId,
4541    state_type: TypeId,
4542}
4543
4544impl AnyWindowHandle {
4545    /// Get the ID of this window.
4546    pub fn window_id(&self) -> WindowId {
4547        self.id
4548    }
4549
4550    /// Attempt to convert this handle to a window handle with a specific root view type.
4551    /// If the types do not match, this will return `None`.
4552    pub fn downcast<T: 'static>(&self) -> Option<WindowHandle<T>> {
4553        if TypeId::of::<T>() == self.state_type {
4554            Some(WindowHandle {
4555                any_handle: *self,
4556                state_type: PhantomData,
4557            })
4558        } else {
4559            None
4560        }
4561    }
4562
4563    /// Updates the state of the root view of this window.
4564    ///
4565    /// This will fail if the window has been closed.
4566    pub fn update<C, R>(
4567        self,
4568        cx: &mut C,
4569        update: impl FnOnce(AnyView, &mut Window, &mut App) -> R,
4570    ) -> Result<R>
4571    where
4572        C: AppContext,
4573    {
4574        cx.update_window(self, update)
4575    }
4576
4577    /// Read the state of the root view of this window.
4578    ///
4579    /// This will fail if the window has been closed.
4580    pub fn read<T, C, R>(self, cx: &C, read: impl FnOnce(Entity<T>, &App) -> R) -> Result<R>
4581    where
4582        C: AppContext,
4583        T: 'static,
4584    {
4585        let view = self
4586            .downcast::<T>()
4587            .context("the type of the window's root view has changed")?;
4588
4589        cx.read_window(&view, read)
4590    }
4591}
4592
4593impl HasWindowHandle for Window {
4594    fn window_handle(&self) -> Result<raw_window_handle::WindowHandle<'_>, HandleError> {
4595        self.platform_window.window_handle()
4596    }
4597}
4598
4599impl HasDisplayHandle for Window {
4600    fn display_handle(
4601        &self,
4602    ) -> std::result::Result<raw_window_handle::DisplayHandle<'_>, HandleError> {
4603        self.platform_window.display_handle()
4604    }
4605}
4606
4607/// An identifier for an [`Element`](crate::Element).
4608///
4609/// Can be constructed with a string, a number, or both, as well
4610/// as other internal representations.
4611#[derive(Clone, Debug, Eq, PartialEq, Hash)]
4612pub enum ElementId {
4613    /// The ID of a View element
4614    View(EntityId),
4615    /// An integer ID.
4616    Integer(u64),
4617    /// A string based ID.
4618    Name(SharedString),
4619    /// A UUID.
4620    Uuid(Uuid),
4621    /// An ID that's equated with a focus handle.
4622    FocusHandle(FocusId),
4623    /// A combination of a name and an integer.
4624    NamedInteger(SharedString, u64),
4625    /// A path.
4626    Path(Arc<std::path::Path>),
4627    /// A code location.
4628    CodeLocation(core::panic::Location<'static>),
4629}
4630
4631impl ElementId {
4632    /// Constructs an `ElementId::NamedInteger` from a name and `usize`.
4633    pub fn named_usize(name: impl Into<SharedString>, integer: usize) -> ElementId {
4634        Self::NamedInteger(name.into(), integer as u64)
4635    }
4636}
4637
4638impl Display for ElementId {
4639    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
4640        match self {
4641            ElementId::View(entity_id) => write!(f, "view-{}", entity_id)?,
4642            ElementId::Integer(ix) => write!(f, "{}", ix)?,
4643            ElementId::Name(name) => write!(f, "{}", name)?,
4644            ElementId::FocusHandle(_) => write!(f, "FocusHandle")?,
4645            ElementId::NamedInteger(s, i) => write!(f, "{}-{}", s, i)?,
4646            ElementId::Uuid(uuid) => write!(f, "{}", uuid)?,
4647            ElementId::Path(path) => write!(f, "{}", path.display())?,
4648            ElementId::CodeLocation(location) => write!(f, "{}", location)?,
4649        }
4650
4651        Ok(())
4652    }
4653}
4654
4655impl TryInto<SharedString> for ElementId {
4656    type Error = anyhow::Error;
4657
4658    fn try_into(self) -> anyhow::Result<SharedString> {
4659        if let ElementId::Name(name) = self {
4660            Ok(name)
4661        } else {
4662            anyhow::bail!("element id is not string")
4663        }
4664    }
4665}
4666
4667impl From<usize> for ElementId {
4668    fn from(id: usize) -> Self {
4669        ElementId::Integer(id as u64)
4670    }
4671}
4672
4673impl From<i32> for ElementId {
4674    fn from(id: i32) -> Self {
4675        Self::Integer(id as u64)
4676    }
4677}
4678
4679impl From<SharedString> for ElementId {
4680    fn from(name: SharedString) -> Self {
4681        ElementId::Name(name)
4682    }
4683}
4684
4685impl From<Arc<std::path::Path>> for ElementId {
4686    fn from(path: Arc<std::path::Path>) -> Self {
4687        ElementId::Path(path)
4688    }
4689}
4690
4691impl From<&'static str> for ElementId {
4692    fn from(name: &'static str) -> Self {
4693        ElementId::Name(name.into())
4694    }
4695}
4696
4697impl<'a> From<&'a FocusHandle> for ElementId {
4698    fn from(handle: &'a FocusHandle) -> Self {
4699        ElementId::FocusHandle(handle.id)
4700    }
4701}
4702
4703impl From<(&'static str, EntityId)> for ElementId {
4704    fn from((name, id): (&'static str, EntityId)) -> Self {
4705        ElementId::NamedInteger(name.into(), id.as_u64())
4706    }
4707}
4708
4709impl From<(&'static str, usize)> for ElementId {
4710    fn from((name, id): (&'static str, usize)) -> Self {
4711        ElementId::NamedInteger(name.into(), id as u64)
4712    }
4713}
4714
4715impl From<(SharedString, usize)> for ElementId {
4716    fn from((name, id): (SharedString, usize)) -> Self {
4717        ElementId::NamedInteger(name, id as u64)
4718    }
4719}
4720
4721impl From<(&'static str, u64)> for ElementId {
4722    fn from((name, id): (&'static str, u64)) -> Self {
4723        ElementId::NamedInteger(name.into(), id)
4724    }
4725}
4726
4727impl From<Uuid> for ElementId {
4728    fn from(value: Uuid) -> Self {
4729        Self::Uuid(value)
4730    }
4731}
4732
4733impl From<(&'static str, u32)> for ElementId {
4734    fn from((name, id): (&'static str, u32)) -> Self {
4735        ElementId::NamedInteger(name.into(), id.into())
4736    }
4737}
4738
4739/// A rectangle to be rendered in the window at the given position and size.
4740/// Passed as an argument [`Window::paint_quad`].
4741#[derive(Clone)]
4742pub struct PaintQuad {
4743    /// The bounds of the quad within the window.
4744    pub bounds: Bounds<Pixels>,
4745    /// The radii of the quad's corners.
4746    pub corner_radii: Corners<Pixels>,
4747    /// The background color of the quad.
4748    pub background: Background,
4749    /// The widths of the quad's borders.
4750    pub border_widths: Edges<Pixels>,
4751    /// The color of the quad's borders.
4752    pub border_color: Hsla,
4753    /// The style of the quad's borders.
4754    pub border_style: BorderStyle,
4755}
4756
4757impl PaintQuad {
4758    /// Sets the corner radii of the quad.
4759    pub fn corner_radii(self, corner_radii: impl Into<Corners<Pixels>>) -> Self {
4760        PaintQuad {
4761            corner_radii: corner_radii.into(),
4762            ..self
4763        }
4764    }
4765
4766    /// Sets the border widths of the quad.
4767    pub fn border_widths(self, border_widths: impl Into<Edges<Pixels>>) -> Self {
4768        PaintQuad {
4769            border_widths: border_widths.into(),
4770            ..self
4771        }
4772    }
4773
4774    /// Sets the border color of the quad.
4775    pub fn border_color(self, border_color: impl Into<Hsla>) -> Self {
4776        PaintQuad {
4777            border_color: border_color.into(),
4778            ..self
4779        }
4780    }
4781
4782    /// Sets the background color of the quad.
4783    pub fn background(self, background: impl Into<Background>) -> Self {
4784        PaintQuad {
4785            background: background.into(),
4786            ..self
4787        }
4788    }
4789}
4790
4791/// Creates a quad with the given parameters.
4792pub fn quad(
4793    bounds: Bounds<Pixels>,
4794    corner_radii: impl Into<Corners<Pixels>>,
4795    background: impl Into<Background>,
4796    border_widths: impl Into<Edges<Pixels>>,
4797    border_color: impl Into<Hsla>,
4798    border_style: BorderStyle,
4799) -> PaintQuad {
4800    PaintQuad {
4801        bounds,
4802        corner_radii: corner_radii.into(),
4803        background: background.into(),
4804        border_widths: border_widths.into(),
4805        border_color: border_color.into(),
4806        border_style,
4807    }
4808}
4809
4810/// Creates a filled quad with the given bounds and background color.
4811pub fn fill(bounds: impl Into<Bounds<Pixels>>, background: impl Into<Background>) -> PaintQuad {
4812    PaintQuad {
4813        bounds: bounds.into(),
4814        corner_radii: (0.).into(),
4815        background: background.into(),
4816        border_widths: (0.).into(),
4817        border_color: transparent_black(),
4818        border_style: BorderStyle::default(),
4819    }
4820}
4821
4822/// Creates a rectangle outline with the given bounds, border color, and a 1px border width
4823pub fn outline(
4824    bounds: impl Into<Bounds<Pixels>>,
4825    border_color: impl Into<Hsla>,
4826    border_style: BorderStyle,
4827) -> PaintQuad {
4828    PaintQuad {
4829        bounds: bounds.into(),
4830        corner_radii: (0.).into(),
4831        background: transparent_black().into(),
4832        border_widths: (1.).into(),
4833        border_color: border_color.into(),
4834        border_style,
4835    }
4836}