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_X, SUBPIXEL_VARIANTS_Y, ScaledPixels, Scene, Shadow,
  15    SharedString, Size, StrikethroughStyle, Style, SubscriberSet, Subscription, SystemWindowTab,
  16    SystemWindowTabController, TabStopMap, TaffyLayoutEngine, Task, TextStyle, TextStyleRefinement,
  17    TransformationMatrix, Underline, UnderlineStyle, WindowAppearance, WindowBackgroundAppearance,
  18    WindowBounds, WindowControls, WindowDecorations, WindowOptions, WindowParams, WindowTextSystem,
  19    point, prelude::*, px, rems, size, transparent_black,
  20};
  21use anyhow::{Context as _, Result, anyhow};
  22use collections::{FxHashMap, FxHashSet};
  23#[cfg(target_os = "macos")]
  24use core_video::pixel_buffer::CVPixelBuffer;
  25use derive_more::{Deref, DerefMut};
  26use futures::FutureExt;
  27use futures::channel::oneshot;
  28use itertools::FoldWhile::{Continue, Done};
  29use itertools::Itertools;
  30use parking_lot::RwLock;
  31use raw_window_handle::{HandleError, HasDisplayHandle, HasWindowHandle};
  32use refineable::Refineable;
  33use slotmap::SlotMap;
  34use smallvec::SmallVec;
  35use std::{
  36    any::{Any, TypeId},
  37    borrow::Cow,
  38    cell::{Cell, RefCell},
  39    cmp,
  40    fmt::{Debug, Display},
  41    hash::{Hash, Hasher},
  42    marker::PhantomData,
  43    mem,
  44    ops::{DerefMut, Range},
  45    rc::Rc,
  46    sync::{
  47        Arc, Weak,
  48        atomic::{AtomicUsize, Ordering::SeqCst},
  49    },
  50    time::{Duration, Instant},
  51};
  52use util::post_inc;
  53use util::{ResultExt, measure};
  54use uuid::Uuid;
  55
  56mod prompts;
  57
  58use crate::util::atomic_incr_if_not_zero;
  59pub use prompts::*;
  60
  61pub(crate) const DEFAULT_WINDOW_SIZE: Size<Pixels> = size(px(1536.), px(864.));
  62
  63/// A 6:5 aspect ratio minimum window size to be used for functional,
  64/// additional-to-main-Zed windows, like the settings and rules library windows.
  65pub const DEFAULT_ADDITIONAL_WINDOW_SIZE: Size<Pixels> = Size {
  66    width: Pixels(900.),
  67    height: Pixels(750.),
  68};
  69
  70/// Represents the two different phases when dispatching events.
  71#[derive(Default, Copy, Clone, Debug, Eq, PartialEq)]
  72pub enum DispatchPhase {
  73    /// After the capture phase comes the bubble phase, in which mouse event listeners are
  74    /// invoked front to back and keyboard event listeners are invoked from the focused element
  75    /// to the root of the element tree. This is the phase you'll most commonly want to use when
  76    /// registering event listeners.
  77    #[default]
  78    Bubble,
  79    /// During the initial capture phase, mouse event listeners are invoked back to front, and keyboard
  80    /// listeners are invoked from the root of the tree downward toward the focused element. This phase
  81    /// is used for special purposes such as clearing the "pressed" state for click events. If
  82    /// you stop event propagation during this phase, you need to know what you're doing. Handlers
  83    /// outside of the immediate region may rely on detecting non-local events during this phase.
  84    Capture,
  85}
  86
  87impl DispatchPhase {
  88    /// Returns true if this represents the "bubble" phase.
  89    #[inline]
  90    pub fn bubble(self) -> bool {
  91        self == DispatchPhase::Bubble
  92    }
  93
  94    /// Returns true if this represents the "capture" phase.
  95    #[inline]
  96    pub fn capture(self) -> bool {
  97        self == DispatchPhase::Capture
  98    }
  99}
 100
 101struct WindowInvalidatorInner {
 102    pub dirty: bool,
 103    pub draw_phase: DrawPhase,
 104    pub dirty_views: FxHashSet<EntityId>,
 105}
 106
 107#[derive(Clone)]
 108pub(crate) struct WindowInvalidator {
 109    inner: Rc<RefCell<WindowInvalidatorInner>>,
 110}
 111
 112impl WindowInvalidator {
 113    pub fn new() -> Self {
 114        WindowInvalidator {
 115            inner: Rc::new(RefCell::new(WindowInvalidatorInner {
 116                dirty: true,
 117                draw_phase: DrawPhase::None,
 118                dirty_views: FxHashSet::default(),
 119            })),
 120        }
 121    }
 122
 123    pub fn invalidate_view(&self, entity: EntityId, cx: &mut App) -> bool {
 124        let mut inner = self.inner.borrow_mut();
 125        inner.dirty_views.insert(entity);
 126        if inner.draw_phase == DrawPhase::None {
 127            inner.dirty = true;
 128            cx.push_effect(Effect::Notify { emitter: entity });
 129            true
 130        } else {
 131            false
 132        }
 133    }
 134
 135    pub fn is_dirty(&self) -> bool {
 136        self.inner.borrow().dirty
 137    }
 138
 139    pub fn set_dirty(&self, dirty: bool) {
 140        self.inner.borrow_mut().dirty = dirty
 141    }
 142
 143    pub fn set_phase(&self, phase: DrawPhase) {
 144        self.inner.borrow_mut().draw_phase = phase
 145    }
 146
 147    pub fn take_views(&self) -> FxHashSet<EntityId> {
 148        mem::take(&mut self.inner.borrow_mut().dirty_views)
 149    }
 150
 151    pub fn replace_views(&self, views: FxHashSet<EntityId>) {
 152        self.inner.borrow_mut().dirty_views = views;
 153    }
 154
 155    pub fn not_drawing(&self) -> bool {
 156        self.inner.borrow().draw_phase == DrawPhase::None
 157    }
 158
 159    #[track_caller]
 160    pub fn debug_assert_paint(&self) {
 161        debug_assert!(
 162            matches!(self.inner.borrow().draw_phase, DrawPhase::Paint),
 163            "this method can only be called during paint"
 164        );
 165    }
 166
 167    #[track_caller]
 168    pub fn debug_assert_prepaint(&self) {
 169        debug_assert!(
 170            matches!(self.inner.borrow().draw_phase, DrawPhase::Prepaint),
 171            "this method can only be called during request_layout, or prepaint"
 172        );
 173    }
 174
 175    #[track_caller]
 176    pub fn debug_assert_paint_or_prepaint(&self) {
 177        debug_assert!(
 178            matches!(
 179                self.inner.borrow().draw_phase,
 180                DrawPhase::Paint | DrawPhase::Prepaint
 181            ),
 182            "this method can only be called during request_layout, prepaint, or paint"
 183        );
 184    }
 185}
 186
 187type AnyObserver = Box<dyn FnMut(&mut Window, &mut App) -> bool + 'static>;
 188
 189pub(crate) type AnyWindowFocusListener =
 190    Box<dyn FnMut(&WindowFocusEvent, &mut Window, &mut App) -> bool + 'static>;
 191
 192pub(crate) struct WindowFocusEvent {
 193    pub(crate) previous_focus_path: SmallVec<[FocusId; 8]>,
 194    pub(crate) current_focus_path: SmallVec<[FocusId; 8]>,
 195}
 196
 197impl WindowFocusEvent {
 198    pub fn is_focus_in(&self, focus_id: FocusId) -> bool {
 199        !self.previous_focus_path.contains(&focus_id) && self.current_focus_path.contains(&focus_id)
 200    }
 201
 202    pub fn is_focus_out(&self, focus_id: FocusId) -> bool {
 203        self.previous_focus_path.contains(&focus_id) && !self.current_focus_path.contains(&focus_id)
 204    }
 205}
 206
 207/// This is provided when subscribing for `Context::on_focus_out` events.
 208pub struct FocusOutEvent {
 209    /// A weak focus handle representing what was blurred.
 210    pub blurred: WeakFocusHandle,
 211}
 212
 213slotmap::new_key_type! {
 214    /// A globally unique identifier for a focusable element.
 215    pub struct FocusId;
 216}
 217
 218thread_local! {
 219    pub(crate) static ELEMENT_ARENA: RefCell<Arena> = RefCell::new(Arena::new(1024 * 1024));
 220}
 221
 222/// Returned when the element arena has been used and so must be cleared before the next draw.
 223#[must_use]
 224pub struct ArenaClearNeeded;
 225
 226impl ArenaClearNeeded {
 227    /// Clear the element arena.
 228    pub fn clear(self) {
 229        ELEMENT_ARENA.with_borrow_mut(|element_arena| {
 230            element_arena.clear();
 231        });
 232    }
 233}
 234
 235pub(crate) type FocusMap = RwLock<SlotMap<FocusId, FocusRef>>;
 236pub(crate) struct FocusRef {
 237    pub(crate) ref_count: AtomicUsize,
 238    pub(crate) tab_index: isize,
 239    pub(crate) tab_stop: bool,
 240}
 241
 242impl FocusId {
 243    /// Obtains whether the element associated with this handle is currently focused.
 244    pub fn is_focused(&self, window: &Window) -> bool {
 245        window.focus == Some(*self)
 246    }
 247
 248    /// Obtains whether the element associated with this handle contains the focused
 249    /// element or is itself focused.
 250    pub fn contains_focused(&self, window: &Window, cx: &App) -> bool {
 251        window
 252            .focused(cx)
 253            .is_some_and(|focused| self.contains(focused.id, window))
 254    }
 255
 256    /// Obtains whether the element associated with this handle is contained within the
 257    /// focused element or is itself focused.
 258    pub fn within_focused(&self, window: &Window, cx: &App) -> bool {
 259        let focused = window.focused(cx);
 260        focused.is_some_and(|focused| focused.id.contains(*self, window))
 261    }
 262
 263    /// Obtains whether this handle contains the given handle in the most recently rendered frame.
 264    pub(crate) fn contains(&self, other: Self, window: &Window) -> bool {
 265        window
 266            .rendered_frame
 267            .dispatch_tree
 268            .focus_contains(*self, other)
 269    }
 270}
 271
 272/// A handle which can be used to track and manipulate the focused element in a window.
 273pub struct FocusHandle {
 274    pub(crate) id: FocusId,
 275    handles: Arc<FocusMap>,
 276    /// The index of this element in the tab order.
 277    pub tab_index: isize,
 278    /// Whether this element can be focused by tab navigation.
 279    pub tab_stop: bool,
 280}
 281
 282impl std::fmt::Debug for FocusHandle {
 283    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 284        f.write_fmt(format_args!("FocusHandle({:?})", self.id))
 285    }
 286}
 287
 288impl FocusHandle {
 289    pub(crate) fn new(handles: &Arc<FocusMap>) -> Self {
 290        let id = handles.write().insert(FocusRef {
 291            ref_count: AtomicUsize::new(1),
 292            tab_index: 0,
 293            tab_stop: false,
 294        });
 295
 296        Self {
 297            id,
 298            tab_index: 0,
 299            tab_stop: false,
 300            handles: handles.clone(),
 301        }
 302    }
 303
 304    pub(crate) fn for_id(id: FocusId, handles: &Arc<FocusMap>) -> Option<Self> {
 305        let lock = handles.read();
 306        let focus = lock.get(id)?;
 307        if atomic_incr_if_not_zero(&focus.ref_count) == 0 {
 308            return None;
 309        }
 310        Some(Self {
 311            id,
 312            tab_index: focus.tab_index,
 313            tab_stop: focus.tab_stop,
 314            handles: handles.clone(),
 315        })
 316    }
 317
 318    /// Sets the tab index of the element associated with this handle.
 319    pub fn tab_index(mut self, index: isize) -> Self {
 320        self.tab_index = index;
 321        if let Some(focus) = self.handles.write().get_mut(self.id) {
 322            focus.tab_index = index;
 323        }
 324        self
 325    }
 326
 327    /// Sets whether the element associated with this handle is a tab stop.
 328    ///
 329    /// When `false`, the element will not be included in the tab order.
 330    pub fn tab_stop(mut self, tab_stop: bool) -> Self {
 331        self.tab_stop = tab_stop;
 332        if let Some(focus) = self.handles.write().get_mut(self.id) {
 333            focus.tab_stop = tab_stop;
 334        }
 335        self
 336    }
 337
 338    /// Converts this focus handle into a weak variant, which does not prevent it from being released.
 339    pub fn downgrade(&self) -> WeakFocusHandle {
 340        WeakFocusHandle {
 341            id: self.id,
 342            handles: Arc::downgrade(&self.handles),
 343        }
 344    }
 345
 346    /// Moves the focus to the element associated with this handle.
 347    pub fn focus(&self, window: &mut Window) {
 348        window.focus(self)
 349    }
 350
 351    /// Obtains whether the element associated with this handle is currently focused.
 352    pub fn is_focused(&self, window: &Window) -> bool {
 353        self.id.is_focused(window)
 354    }
 355
 356    /// Obtains whether the element associated with this handle contains the focused
 357    /// element or is itself focused.
 358    pub fn contains_focused(&self, window: &Window, cx: &App) -> bool {
 359        self.id.contains_focused(window, cx)
 360    }
 361
 362    /// Obtains whether the element associated with this handle is contained within the
 363    /// focused element or is itself focused.
 364    pub fn within_focused(&self, window: &Window, cx: &mut App) -> bool {
 365        self.id.within_focused(window, cx)
 366    }
 367
 368    /// Obtains whether this handle contains the given handle in the most recently rendered frame.
 369    pub fn contains(&self, other: &Self, window: &Window) -> bool {
 370        self.id.contains(other.id, window)
 371    }
 372
 373    /// Dispatch an action on the element that rendered this focus handle
 374    pub fn dispatch_action(&self, action: &dyn Action, window: &mut Window, cx: &mut App) {
 375        if let Some(node_id) = window
 376            .rendered_frame
 377            .dispatch_tree
 378            .focusable_node_id(self.id)
 379        {
 380            window.dispatch_action_on_node(node_id, action, cx)
 381        }
 382    }
 383}
 384
 385impl Clone for FocusHandle {
 386    fn clone(&self) -> Self {
 387        Self::for_id(self.id, &self.handles).unwrap()
 388    }
 389}
 390
 391impl PartialEq for FocusHandle {
 392    fn eq(&self, other: &Self) -> bool {
 393        self.id == other.id
 394    }
 395}
 396
 397impl Eq for FocusHandle {}
 398
 399impl Drop for FocusHandle {
 400    fn drop(&mut self) {
 401        self.handles
 402            .read()
 403            .get(self.id)
 404            .unwrap()
 405            .ref_count
 406            .fetch_sub(1, SeqCst);
 407    }
 408}
 409
 410/// A weak reference to a focus handle.
 411#[derive(Clone, Debug)]
 412pub struct WeakFocusHandle {
 413    pub(crate) id: FocusId,
 414    pub(crate) handles: Weak<FocusMap>,
 415}
 416
 417impl WeakFocusHandle {
 418    /// Attempts to upgrade the [WeakFocusHandle] to a [FocusHandle].
 419    pub fn upgrade(&self) -> Option<FocusHandle> {
 420        let handles = self.handles.upgrade()?;
 421        FocusHandle::for_id(self.id, &handles)
 422    }
 423}
 424
 425impl PartialEq for WeakFocusHandle {
 426    fn eq(&self, other: &WeakFocusHandle) -> bool {
 427        self.id == other.id
 428    }
 429}
 430
 431impl Eq for WeakFocusHandle {}
 432
 433impl PartialEq<FocusHandle> for WeakFocusHandle {
 434    fn eq(&self, other: &FocusHandle) -> bool {
 435        self.id == other.id
 436    }
 437}
 438
 439impl PartialEq<WeakFocusHandle> for FocusHandle {
 440    fn eq(&self, other: &WeakFocusHandle) -> bool {
 441        self.id == other.id
 442    }
 443}
 444
 445/// Focusable allows users of your view to easily
 446/// focus it (using window.focus_view(cx, view))
 447pub trait Focusable: 'static {
 448    /// Returns the focus handle associated with this view.
 449    fn focus_handle(&self, cx: &App) -> FocusHandle;
 450}
 451
 452impl<V: Focusable> Focusable for Entity<V> {
 453    fn focus_handle(&self, cx: &App) -> FocusHandle {
 454        self.read(cx).focus_handle(cx)
 455    }
 456}
 457
 458/// ManagedView is a view (like a Modal, Popover, Menu, etc.)
 459/// where the lifecycle of the view is handled by another view.
 460pub trait ManagedView: Focusable + EventEmitter<DismissEvent> + Render {}
 461
 462impl<M: Focusable + EventEmitter<DismissEvent> + Render> ManagedView for M {}
 463
 464/// Emitted by implementers of [`ManagedView`] to indicate the view should be dismissed, such as when a view is presented as a modal.
 465pub struct DismissEvent;
 466
 467type FrameCallback = Box<dyn FnOnce(&mut Window, &mut App)>;
 468
 469pub(crate) type AnyMouseListener =
 470    Box<dyn FnMut(&dyn Any, DispatchPhase, &mut Window, &mut App) + 'static>;
 471
 472#[derive(Clone)]
 473pub(crate) struct CursorStyleRequest {
 474    pub(crate) hitbox_id: Option<HitboxId>,
 475    pub(crate) style: CursorStyle,
 476}
 477
 478#[derive(Default, Eq, PartialEq)]
 479pub(crate) struct HitTest {
 480    pub(crate) ids: SmallVec<[HitboxId; 8]>,
 481    pub(crate) hover_hitbox_count: usize,
 482}
 483
 484/// A type of window control area that corresponds to the platform window.
 485#[derive(Clone, Copy, Debug, Eq, PartialEq)]
 486pub enum WindowControlArea {
 487    /// An area that allows dragging of the platform window.
 488    Drag,
 489    /// An area that allows closing of the platform window.
 490    Close,
 491    /// An area that allows maximizing of the platform window.
 492    Max,
 493    /// An area that allows minimizing of the platform window.
 494    Min,
 495}
 496
 497/// An identifier for a [Hitbox] which also includes [HitboxBehavior].
 498#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
 499pub struct HitboxId(u64);
 500
 501impl HitboxId {
 502    /// Checks if the hitbox with this ID is currently hovered. Except when handling
 503    /// `ScrollWheelEvent`, this is typically what you want when determining whether to handle mouse
 504    /// events or paint hover styles.
 505    ///
 506    /// See [`Hitbox::is_hovered`] for details.
 507    pub fn is_hovered(self, window: &Window) -> bool {
 508        let hit_test = &window.mouse_hit_test;
 509        for id in hit_test.ids.iter().take(hit_test.hover_hitbox_count) {
 510            if self == *id {
 511                return true;
 512            }
 513        }
 514        false
 515    }
 516
 517    /// Checks if the hitbox with this ID contains the mouse and should handle scroll events.
 518    /// Typically this should only be used when handling `ScrollWheelEvent`, and otherwise
 519    /// `is_hovered` should be used. See the documentation of `Hitbox::is_hovered` for details about
 520    /// this distinction.
 521    pub fn should_handle_scroll(self, window: &Window) -> bool {
 522        window.mouse_hit_test.ids.contains(&self)
 523    }
 524
 525    fn next(mut self) -> HitboxId {
 526        HitboxId(self.0.wrapping_add(1))
 527    }
 528}
 529
 530/// A rectangular region that potentially blocks hitboxes inserted prior.
 531/// See [Window::insert_hitbox] for more details.
 532#[derive(Clone, Debug, Deref)]
 533pub struct Hitbox {
 534    /// A unique identifier for the hitbox.
 535    pub id: HitboxId,
 536    /// The bounds of the hitbox.
 537    #[deref]
 538    pub bounds: Bounds<Pixels>,
 539    /// The content mask when the hitbox was inserted.
 540    pub content_mask: ContentMask<Pixels>,
 541    /// Flags that specify hitbox behavior.
 542    pub behavior: HitboxBehavior,
 543}
 544
 545impl Hitbox {
 546    /// Checks if the hitbox is currently hovered. Except when handling `ScrollWheelEvent`, this is
 547    /// typically what you want when determining whether to handle mouse events or paint hover
 548    /// styles.
 549    ///
 550    /// This can return `false` even when the hitbox contains the mouse, if a hitbox in front of
 551    /// this sets `HitboxBehavior::BlockMouse` (`InteractiveElement::occlude`) or
 552    /// `HitboxBehavior::BlockMouseExceptScroll` (`InteractiveElement::block_mouse_except_scroll`).
 553    ///
 554    /// Handling of `ScrollWheelEvent` should typically use `should_handle_scroll` instead.
 555    /// Concretely, this is due to use-cases like overlays that cause the elements under to be
 556    /// non-interactive while still allowing scrolling. More abstractly, this is because
 557    /// `is_hovered` is about element interactions directly under the mouse - mouse moves, clicks,
 558    /// hover styling, etc. In contrast, scrolling is about finding the current outer scrollable
 559    /// container.
 560    pub fn is_hovered(&self, window: &Window) -> bool {
 561        self.id.is_hovered(window)
 562    }
 563
 564    /// Checks if the hitbox contains the mouse and should handle scroll events. Typically this
 565    /// should only be used when handling `ScrollWheelEvent`, and otherwise `is_hovered` should be
 566    /// used. See the documentation of `Hitbox::is_hovered` for details about this distinction.
 567    ///
 568    /// This can return `false` even when the hitbox contains the mouse, if a hitbox in front of
 569    /// this sets `HitboxBehavior::BlockMouse` (`InteractiveElement::occlude`).
 570    pub fn should_handle_scroll(&self, window: &Window) -> bool {
 571        self.id.should_handle_scroll(window)
 572    }
 573}
 574
 575/// How the hitbox affects mouse behavior.
 576#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 577pub enum HitboxBehavior {
 578    /// Normal hitbox mouse behavior, doesn't affect mouse handling for other hitboxes.
 579    #[default]
 580    Normal,
 581
 582    /// All hitboxes behind this hitbox will be ignored and so will have `hitbox.is_hovered() ==
 583    /// false` and `hitbox.should_handle_scroll() == false`. Typically for elements this causes
 584    /// skipping of all mouse events, hover styles, and tooltips. This flag is set by
 585    /// [`InteractiveElement::occlude`].
 586    ///
 587    /// For mouse handlers that check those hitboxes, this behaves the same as registering a
 588    /// bubble-phase handler for every mouse event type:
 589    ///
 590    /// ```ignore
 591    /// window.on_mouse_event(move |_: &EveryMouseEventTypeHere, phase, window, cx| {
 592    ///     if phase == DispatchPhase::Capture && hitbox.is_hovered(window) {
 593    ///         cx.stop_propagation();
 594    ///     }
 595    /// })
 596    /// ```
 597    ///
 598    /// This has effects beyond event handling - any use of hitbox checking, such as hover
 599    /// styles and tooltops. These other behaviors are the main point of this mechanism. An
 600    /// alternative might be to not affect mouse event handling - but this would allow
 601    /// inconsistent UI where clicks and moves interact with elements that are not considered to
 602    /// be hovered.
 603    BlockMouse,
 604
 605    /// All hitboxes behind this hitbox will have `hitbox.is_hovered() == false`, even when
 606    /// `hitbox.should_handle_scroll() == true`. Typically for elements this causes all mouse
 607    /// interaction except scroll events to be ignored - see the documentation of
 608    /// [`Hitbox::is_hovered`] for details. This flag is set by
 609    /// [`InteractiveElement::block_mouse_except_scroll`].
 610    ///
 611    /// For mouse handlers that check those hitboxes, this behaves the same as registering a
 612    /// bubble-phase handler for every mouse event type **except** `ScrollWheelEvent`:
 613    ///
 614    /// ```ignore
 615    /// window.on_mouse_event(move |_: &EveryMouseEventTypeExceptScroll, phase, window, cx| {
 616    ///     if phase == DispatchPhase::Bubble && hitbox.should_handle_scroll(window) {
 617    ///         cx.stop_propagation();
 618    ///     }
 619    /// })
 620    /// ```
 621    ///
 622    /// See the documentation of [`Hitbox::is_hovered`] for details of why `ScrollWheelEvent` is
 623    /// handled differently than other mouse events. If also blocking these scroll events is
 624    /// desired, then a `cx.stop_propagation()` handler like the one above can be used.
 625    ///
 626    /// This has effects beyond event handling - this affects any use of `is_hovered`, such as
 627    /// hover styles and tooltops. These other behaviors are the main point of this mechanism.
 628    /// An alternative might be to not affect mouse event handling - but this would allow
 629    /// inconsistent UI where clicks and moves interact with elements that are not considered to
 630    /// be hovered.
 631    BlockMouseExceptScroll,
 632}
 633
 634/// An identifier for a tooltip.
 635#[derive(Copy, Clone, Debug, Default, Eq, PartialEq)]
 636pub struct TooltipId(usize);
 637
 638impl TooltipId {
 639    /// Checks if the tooltip is currently hovered.
 640    pub fn is_hovered(&self, window: &Window) -> bool {
 641        window
 642            .tooltip_bounds
 643            .as_ref()
 644            .is_some_and(|tooltip_bounds| {
 645                tooltip_bounds.id == *self
 646                    && tooltip_bounds.bounds.contains(&window.mouse_position())
 647            })
 648    }
 649}
 650
 651pub(crate) struct TooltipBounds {
 652    id: TooltipId,
 653    bounds: Bounds<Pixels>,
 654}
 655
 656#[derive(Clone)]
 657pub(crate) struct TooltipRequest {
 658    id: TooltipId,
 659    tooltip: AnyTooltip,
 660}
 661
 662pub(crate) struct DeferredDraw {
 663    current_view: EntityId,
 664    priority: usize,
 665    parent_node: DispatchNodeId,
 666    element_id_stack: SmallVec<[ElementId; 32]>,
 667    text_style_stack: Vec<TextStyleRefinement>,
 668    element: Option<AnyElement>,
 669    absolute_offset: Point<Pixels>,
 670    prepaint_range: Range<PrepaintStateIndex>,
 671    paint_range: Range<PaintIndex>,
 672}
 673
 674pub(crate) struct Frame {
 675    pub(crate) focus: Option<FocusId>,
 676    pub(crate) window_active: bool,
 677    pub(crate) element_states: FxHashMap<(GlobalElementId, TypeId), ElementStateBox>,
 678    accessed_element_states: Vec<(GlobalElementId, TypeId)>,
 679    pub(crate) mouse_listeners: Vec<Option<AnyMouseListener>>,
 680    pub(crate) dispatch_tree: DispatchTree,
 681    pub(crate) scene: Scene,
 682    pub(crate) hitboxes: Vec<Hitbox>,
 683    pub(crate) window_control_hitboxes: Vec<(WindowControlArea, Hitbox)>,
 684    pub(crate) deferred_draws: Vec<DeferredDraw>,
 685    pub(crate) input_handlers: Vec<Option<PlatformInputHandler>>,
 686    pub(crate) tooltip_requests: Vec<Option<TooltipRequest>>,
 687    pub(crate) cursor_styles: Vec<CursorStyleRequest>,
 688    #[cfg(any(test, feature = "test-support"))]
 689    pub(crate) debug_bounds: FxHashMap<String, Bounds<Pixels>>,
 690    #[cfg(any(feature = "inspector", debug_assertions))]
 691    pub(crate) next_inspector_instance_ids: FxHashMap<Rc<crate::InspectorElementPath>, usize>,
 692    #[cfg(any(feature = "inspector", debug_assertions))]
 693    pub(crate) inspector_hitboxes: FxHashMap<HitboxId, crate::InspectorElementId>,
 694    pub(crate) tab_stops: TabStopMap,
 695}
 696
 697#[derive(Clone, Default)]
 698pub(crate) struct PrepaintStateIndex {
 699    hitboxes_index: usize,
 700    tooltips_index: usize,
 701    deferred_draws_index: usize,
 702    dispatch_tree_index: usize,
 703    accessed_element_states_index: usize,
 704    line_layout_index: LineLayoutIndex,
 705}
 706
 707#[derive(Clone, Default)]
 708pub(crate) struct PaintIndex {
 709    scene_index: usize,
 710    mouse_listeners_index: usize,
 711    input_handlers_index: usize,
 712    cursor_styles_index: usize,
 713    accessed_element_states_index: usize,
 714    tab_handle_index: usize,
 715    line_layout_index: LineLayoutIndex,
 716}
 717
 718impl Frame {
 719    pub(crate) fn new(dispatch_tree: DispatchTree) -> Self {
 720        Frame {
 721            focus: None,
 722            window_active: false,
 723            element_states: FxHashMap::default(),
 724            accessed_element_states: Vec::new(),
 725            mouse_listeners: Vec::new(),
 726            dispatch_tree,
 727            scene: Scene::default(),
 728            hitboxes: Vec::new(),
 729            window_control_hitboxes: Vec::new(),
 730            deferred_draws: Vec::new(),
 731            input_handlers: Vec::new(),
 732            tooltip_requests: Vec::new(),
 733            cursor_styles: Vec::new(),
 734
 735            #[cfg(any(test, feature = "test-support"))]
 736            debug_bounds: FxHashMap::default(),
 737
 738            #[cfg(any(feature = "inspector", debug_assertions))]
 739            next_inspector_instance_ids: FxHashMap::default(),
 740
 741            #[cfg(any(feature = "inspector", debug_assertions))]
 742            inspector_hitboxes: FxHashMap::default(),
 743            tab_stops: TabStopMap::default(),
 744        }
 745    }
 746
 747    pub(crate) fn clear(&mut self) {
 748        self.element_states.clear();
 749        self.accessed_element_states.clear();
 750        self.mouse_listeners.clear();
 751        self.dispatch_tree.clear();
 752        self.scene.clear();
 753        self.input_handlers.clear();
 754        self.tooltip_requests.clear();
 755        self.cursor_styles.clear();
 756        self.hitboxes.clear();
 757        self.window_control_hitboxes.clear();
 758        self.deferred_draws.clear();
 759        self.tab_stops.clear();
 760        self.focus = None;
 761
 762        #[cfg(any(feature = "inspector", debug_assertions))]
 763        {
 764            self.next_inspector_instance_ids.clear();
 765            self.inspector_hitboxes.clear();
 766        }
 767    }
 768
 769    pub(crate) fn cursor_style(&self, window: &Window) -> Option<CursorStyle> {
 770        self.cursor_styles
 771            .iter()
 772            .rev()
 773            .fold_while(None, |style, request| match request.hitbox_id {
 774                None => Done(Some(request.style)),
 775                Some(hitbox_id) => Continue(
 776                    style.or_else(|| hitbox_id.is_hovered(window).then_some(request.style)),
 777                ),
 778            })
 779            .into_inner()
 780    }
 781
 782    pub(crate) fn hit_test(&self, position: Point<Pixels>) -> HitTest {
 783        let mut set_hover_hitbox_count = false;
 784        let mut hit_test = HitTest::default();
 785        for hitbox in self.hitboxes.iter().rev() {
 786            let bounds = hitbox.bounds.intersect(&hitbox.content_mask.bounds);
 787            if bounds.contains(&position) {
 788                hit_test.ids.push(hitbox.id);
 789                if !set_hover_hitbox_count
 790                    && hitbox.behavior == HitboxBehavior::BlockMouseExceptScroll
 791                {
 792                    hit_test.hover_hitbox_count = hit_test.ids.len();
 793                    set_hover_hitbox_count = true;
 794                }
 795                if hitbox.behavior == HitboxBehavior::BlockMouse {
 796                    break;
 797                }
 798            }
 799        }
 800        if !set_hover_hitbox_count {
 801            hit_test.hover_hitbox_count = hit_test.ids.len();
 802        }
 803        hit_test
 804    }
 805
 806    pub(crate) fn focus_path(&self) -> SmallVec<[FocusId; 8]> {
 807        self.focus
 808            .map(|focus_id| self.dispatch_tree.focus_path(focus_id))
 809            .unwrap_or_default()
 810    }
 811
 812    pub(crate) fn finish(&mut self, prev_frame: &mut Self) {
 813        for element_state_key in &self.accessed_element_states {
 814            if let Some((element_state_key, element_state)) =
 815                prev_frame.element_states.remove_entry(element_state_key)
 816            {
 817                self.element_states.insert(element_state_key, element_state);
 818            }
 819        }
 820
 821        self.scene.finish();
 822    }
 823}
 824
 825/// Holds the state for a specific window.
 826pub struct Window {
 827    pub(crate) handle: AnyWindowHandle,
 828    pub(crate) invalidator: WindowInvalidator,
 829    pub(crate) removed: bool,
 830    pub(crate) platform_window: Box<dyn PlatformWindow>,
 831    display_id: Option<DisplayId>,
 832    sprite_atlas: Arc<dyn PlatformAtlas>,
 833    text_system: Arc<WindowTextSystem>,
 834    rem_size: Pixels,
 835    /// The stack of override values for the window's rem size.
 836    ///
 837    /// This is used by `with_rem_size` to allow rendering an element tree with
 838    /// a given rem size.
 839    rem_size_override_stack: SmallVec<[Pixels; 8]>,
 840    pub(crate) viewport_size: Size<Pixels>,
 841    layout_engine: Option<TaffyLayoutEngine>,
 842    pub(crate) root: Option<AnyView>,
 843    pub(crate) element_id_stack: SmallVec<[ElementId; 32]>,
 844    pub(crate) text_style_stack: Vec<TextStyleRefinement>,
 845    pub(crate) rendered_entity_stack: Vec<EntityId>,
 846    pub(crate) element_offset_stack: Vec<Point<Pixels>>,
 847    pub(crate) element_opacity: f32,
 848    pub(crate) content_mask_stack: Vec<ContentMask<Pixels>>,
 849    pub(crate) requested_autoscroll: Option<Bounds<Pixels>>,
 850    pub(crate) image_cache_stack: Vec<AnyImageCache>,
 851    pub(crate) rendered_frame: Frame,
 852    pub(crate) next_frame: Frame,
 853    next_hitbox_id: HitboxId,
 854    pub(crate) next_tooltip_id: TooltipId,
 855    pub(crate) tooltip_bounds: Option<TooltipBounds>,
 856    next_frame_callbacks: Rc<RefCell<Vec<FrameCallback>>>,
 857    pub(crate) dirty_views: FxHashSet<EntityId>,
 858    focus_listeners: SubscriberSet<(), AnyWindowFocusListener>,
 859    pub(crate) focus_lost_listeners: SubscriberSet<(), AnyObserver>,
 860    default_prevented: bool,
 861    mouse_position: Point<Pixels>,
 862    mouse_hit_test: HitTest,
 863    modifiers: Modifiers,
 864    capslock: Capslock,
 865    scale_factor: f32,
 866    pub(crate) bounds_observers: SubscriberSet<(), AnyObserver>,
 867    appearance: WindowAppearance,
 868    pub(crate) appearance_observers: SubscriberSet<(), AnyObserver>,
 869    active: Rc<Cell<bool>>,
 870    hovered: Rc<Cell<bool>>,
 871    pub(crate) needs_present: Rc<Cell<bool>>,
 872    pub(crate) last_input_timestamp: Rc<Cell<Instant>>,
 873    last_input_was_keyboard: bool,
 874    pub(crate) refreshing: bool,
 875    pub(crate) activation_observers: SubscriberSet<(), AnyObserver>,
 876    pub(crate) focus: Option<FocusId>,
 877    focus_enabled: bool,
 878    pending_input: Option<PendingInput>,
 879    pending_modifier: ModifierState,
 880    pub(crate) pending_input_observers: SubscriberSet<(), AnyObserver>,
 881    prompt: Option<RenderablePromptHandle>,
 882    pub(crate) client_inset: Option<Pixels>,
 883    #[cfg(any(feature = "inspector", debug_assertions))]
 884    inspector: Option<Entity<Inspector>>,
 885}
 886
 887#[derive(Clone, Debug, Default)]
 888struct ModifierState {
 889    modifiers: Modifiers,
 890    saw_keystroke: bool,
 891}
 892
 893#[derive(Clone, Copy, Debug, Eq, PartialEq)]
 894pub(crate) enum DrawPhase {
 895    None,
 896    Prepaint,
 897    Paint,
 898    Focus,
 899}
 900
 901#[derive(Default, Debug)]
 902struct PendingInput {
 903    keystrokes: SmallVec<[Keystroke; 1]>,
 904    focus: Option<FocusId>,
 905    timer: Option<Task<()>>,
 906}
 907
 908pub(crate) struct ElementStateBox {
 909    pub(crate) inner: Box<dyn Any>,
 910    #[cfg(debug_assertions)]
 911    pub(crate) type_name: &'static str,
 912}
 913
 914fn default_bounds(display_id: Option<DisplayId>, cx: &mut App) -> Bounds<Pixels> {
 915    const DEFAULT_WINDOW_OFFSET: Point<Pixels> = point(px(0.), px(35.));
 916
 917    // TODO, BUG: if you open a window with the currently active window
 918    // on the stack, this will erroneously select the 'unwrap_or_else'
 919    // code path
 920    cx.active_window()
 921        .and_then(|w| w.update(cx, |_, window, _| window.bounds()).ok())
 922        .map(|mut bounds| {
 923            bounds.origin += DEFAULT_WINDOW_OFFSET;
 924            bounds
 925        })
 926        .unwrap_or_else(|| {
 927            let display = display_id
 928                .map(|id| cx.find_display(id))
 929                .unwrap_or_else(|| cx.primary_display());
 930
 931            display
 932                .map(|display| display.default_bounds())
 933                .unwrap_or_else(|| Bounds::new(point(px(0.), px(0.)), DEFAULT_WINDOW_SIZE))
 934        })
 935}
 936
 937impl Window {
 938    pub(crate) fn new(
 939        handle: AnyWindowHandle,
 940        options: WindowOptions,
 941        cx: &mut App,
 942    ) -> Result<Self> {
 943        let WindowOptions {
 944            window_bounds,
 945            titlebar,
 946            focus,
 947            show,
 948            kind,
 949            is_movable,
 950            is_resizable,
 951            is_minimizable,
 952            display_id,
 953            window_background,
 954            app_id,
 955            window_min_size,
 956            window_decorations,
 957            #[cfg_attr(not(target_os = "macos"), allow(unused_variables))]
 958            tabbing_identifier,
 959        } = options;
 960
 961        let bounds = window_bounds
 962            .map(|bounds| bounds.get_bounds())
 963            .unwrap_or_else(|| default_bounds(display_id, cx));
 964        let mut platform_window = cx.platform.open_window(
 965            handle,
 966            WindowParams {
 967                bounds,
 968                titlebar,
 969                kind,
 970                is_movable,
 971                is_resizable,
 972                is_minimizable,
 973                focus,
 974                show,
 975                display_id,
 976                window_min_size,
 977                #[cfg(target_os = "macos")]
 978                tabbing_identifier,
 979            },
 980        )?;
 981
 982        let tab_bar_visible = platform_window.tab_bar_visible();
 983        SystemWindowTabController::init_visible(cx, tab_bar_visible);
 984        if let Some(tabs) = platform_window.tabbed_windows() {
 985            SystemWindowTabController::add_tab(cx, handle.window_id(), tabs);
 986        }
 987
 988        let display_id = platform_window.display().map(|display| display.id());
 989        let sprite_atlas = platform_window.sprite_atlas();
 990        let mouse_position = platform_window.mouse_position();
 991        let modifiers = platform_window.modifiers();
 992        let capslock = platform_window.capslock();
 993        let content_size = platform_window.content_size();
 994        let scale_factor = platform_window.scale_factor();
 995        let appearance = platform_window.appearance();
 996        let text_system = Arc::new(WindowTextSystem::new(cx.text_system().clone()));
 997        let invalidator = WindowInvalidator::new();
 998        let active = Rc::new(Cell::new(platform_window.is_active()));
 999        let hovered = Rc::new(Cell::new(platform_window.is_hovered()));
1000        let needs_present = Rc::new(Cell::new(false));
1001        let next_frame_callbacks: Rc<RefCell<Vec<FrameCallback>>> = Default::default();
1002        let last_input_timestamp = Rc::new(Cell::new(Instant::now()));
1003
1004        platform_window
1005            .request_decorations(window_decorations.unwrap_or(WindowDecorations::Server));
1006        platform_window.set_background_appearance(window_background);
1007
1008        if let Some(ref window_open_state) = window_bounds {
1009            match window_open_state {
1010                WindowBounds::Fullscreen(_) => platform_window.toggle_fullscreen(),
1011                WindowBounds::Maximized(_) => platform_window.zoom(),
1012                WindowBounds::Windowed(_) => {}
1013            }
1014        }
1015
1016        platform_window.on_close(Box::new({
1017            let window_id = handle.window_id();
1018            let mut cx = cx.to_async();
1019            move || {
1020                let _ = handle.update(&mut cx, |_, window, _| window.remove_window());
1021                let _ = cx.update(|cx| {
1022                    SystemWindowTabController::remove_tab(cx, window_id);
1023                });
1024            }
1025        }));
1026        platform_window.on_request_frame(Box::new({
1027            let mut cx = cx.to_async();
1028            let invalidator = invalidator.clone();
1029            let active = active.clone();
1030            let needs_present = needs_present.clone();
1031            let next_frame_callbacks = next_frame_callbacks.clone();
1032            let last_input_timestamp = last_input_timestamp.clone();
1033            move |request_frame_options| {
1034                let next_frame_callbacks = next_frame_callbacks.take();
1035                if !next_frame_callbacks.is_empty() {
1036                    handle
1037                        .update(&mut cx, |_, window, cx| {
1038                            for callback in next_frame_callbacks {
1039                                callback(window, cx);
1040                            }
1041                        })
1042                        .log_err();
1043                }
1044
1045                // Keep presenting the current scene for 1 extra second since the
1046                // last input to prevent the display from underclocking the refresh rate.
1047                let needs_present = request_frame_options.require_presentation
1048                    || needs_present.get()
1049                    || (active.get()
1050                        && last_input_timestamp.get().elapsed() < Duration::from_secs(1));
1051
1052                if invalidator.is_dirty() || request_frame_options.force_render {
1053                    measure("frame duration", || {
1054                        handle
1055                            .update(&mut cx, |_, window, cx| {
1056                                let arena_clear_needed = window.draw(cx);
1057                                window.present();
1058                                // drop the arena elements after present to reduce latency
1059                                arena_clear_needed.clear();
1060                            })
1061                            .log_err();
1062                    })
1063                } else if needs_present {
1064                    handle
1065                        .update(&mut cx, |_, window, _| window.present())
1066                        .log_err();
1067                }
1068
1069                handle
1070                    .update(&mut cx, |_, window, _| {
1071                        window.complete_frame();
1072                    })
1073                    .log_err();
1074            }
1075        }));
1076        platform_window.on_resize(Box::new({
1077            let mut cx = cx.to_async();
1078            move |_, _| {
1079                handle
1080                    .update(&mut cx, |_, window, cx| window.bounds_changed(cx))
1081                    .log_err();
1082            }
1083        }));
1084        platform_window.on_moved(Box::new({
1085            let mut cx = cx.to_async();
1086            move || {
1087                handle
1088                    .update(&mut cx, |_, window, cx| window.bounds_changed(cx))
1089                    .log_err();
1090            }
1091        }));
1092        platform_window.on_appearance_changed(Box::new({
1093            let mut cx = cx.to_async();
1094            move || {
1095                handle
1096                    .update(&mut cx, |_, window, cx| window.appearance_changed(cx))
1097                    .log_err();
1098            }
1099        }));
1100        platform_window.on_active_status_change(Box::new({
1101            let mut cx = cx.to_async();
1102            move |active| {
1103                handle
1104                    .update(&mut cx, |_, window, cx| {
1105                        window.active.set(active);
1106                        window.modifiers = window.platform_window.modifiers();
1107                        window.capslock = window.platform_window.capslock();
1108                        window
1109                            .activation_observers
1110                            .clone()
1111                            .retain(&(), |callback| callback(window, cx));
1112
1113                        window.bounds_changed(cx);
1114                        window.refresh();
1115
1116                        SystemWindowTabController::update_last_active(cx, window.handle.id);
1117                    })
1118                    .log_err();
1119            }
1120        }));
1121        platform_window.on_hover_status_change(Box::new({
1122            let mut cx = cx.to_async();
1123            move |active| {
1124                handle
1125                    .update(&mut cx, |_, window, _| {
1126                        window.hovered.set(active);
1127                        window.refresh();
1128                    })
1129                    .log_err();
1130            }
1131        }));
1132        platform_window.on_input({
1133            let mut cx = cx.to_async();
1134            Box::new(move |event| {
1135                handle
1136                    .update(&mut cx, |_, window, cx| window.dispatch_event(event, cx))
1137                    .log_err()
1138                    .unwrap_or(DispatchEventResult::default())
1139            })
1140        });
1141        platform_window.on_hit_test_window_control({
1142            let mut cx = cx.to_async();
1143            Box::new(move || {
1144                handle
1145                    .update(&mut cx, |_, window, _cx| {
1146                        for (area, hitbox) in &window.rendered_frame.window_control_hitboxes {
1147                            if window.mouse_hit_test.ids.contains(&hitbox.id) {
1148                                return Some(*area);
1149                            }
1150                        }
1151                        None
1152                    })
1153                    .log_err()
1154                    .unwrap_or(None)
1155            })
1156        });
1157        platform_window.on_move_tab_to_new_window({
1158            let mut cx = cx.to_async();
1159            Box::new(move || {
1160                handle
1161                    .update(&mut cx, |_, _window, cx| {
1162                        SystemWindowTabController::move_tab_to_new_window(cx, handle.window_id());
1163                    })
1164                    .log_err();
1165            })
1166        });
1167        platform_window.on_merge_all_windows({
1168            let mut cx = cx.to_async();
1169            Box::new(move || {
1170                handle
1171                    .update(&mut cx, |_, _window, cx| {
1172                        SystemWindowTabController::merge_all_windows(cx, handle.window_id());
1173                    })
1174                    .log_err();
1175            })
1176        });
1177        platform_window.on_select_next_tab({
1178            let mut cx = cx.to_async();
1179            Box::new(move || {
1180                handle
1181                    .update(&mut cx, |_, _window, cx| {
1182                        SystemWindowTabController::select_next_tab(cx, handle.window_id());
1183                    })
1184                    .log_err();
1185            })
1186        });
1187        platform_window.on_select_previous_tab({
1188            let mut cx = cx.to_async();
1189            Box::new(move || {
1190                handle
1191                    .update(&mut cx, |_, _window, cx| {
1192                        SystemWindowTabController::select_previous_tab(cx, handle.window_id())
1193                    })
1194                    .log_err();
1195            })
1196        });
1197        platform_window.on_toggle_tab_bar({
1198            let mut cx = cx.to_async();
1199            Box::new(move || {
1200                handle
1201                    .update(&mut cx, |_, window, cx| {
1202                        let tab_bar_visible = window.platform_window.tab_bar_visible();
1203                        SystemWindowTabController::set_visible(cx, tab_bar_visible);
1204                    })
1205                    .log_err();
1206            })
1207        });
1208
1209        if let Some(app_id) = app_id {
1210            platform_window.set_app_id(&app_id);
1211        }
1212
1213        platform_window.map_window().unwrap();
1214
1215        Ok(Window {
1216            handle,
1217            invalidator,
1218            removed: false,
1219            platform_window,
1220            display_id,
1221            sprite_atlas,
1222            text_system,
1223            rem_size: px(16.),
1224            rem_size_override_stack: SmallVec::new(),
1225            viewport_size: content_size,
1226            layout_engine: Some(TaffyLayoutEngine::new()),
1227            root: None,
1228            element_id_stack: SmallVec::default(),
1229            text_style_stack: Vec::new(),
1230            rendered_entity_stack: Vec::new(),
1231            element_offset_stack: Vec::new(),
1232            content_mask_stack: Vec::new(),
1233            element_opacity: 1.0,
1234            requested_autoscroll: None,
1235            rendered_frame: Frame::new(DispatchTree::new(cx.keymap.clone(), cx.actions.clone())),
1236            next_frame: Frame::new(DispatchTree::new(cx.keymap.clone(), cx.actions.clone())),
1237            next_frame_callbacks,
1238            next_hitbox_id: HitboxId(0),
1239            next_tooltip_id: TooltipId::default(),
1240            tooltip_bounds: None,
1241            dirty_views: FxHashSet::default(),
1242            focus_listeners: SubscriberSet::new(),
1243            focus_lost_listeners: SubscriberSet::new(),
1244            default_prevented: true,
1245            mouse_position,
1246            mouse_hit_test: HitTest::default(),
1247            modifiers,
1248            capslock,
1249            scale_factor,
1250            bounds_observers: SubscriberSet::new(),
1251            appearance,
1252            appearance_observers: SubscriberSet::new(),
1253            active,
1254            hovered,
1255            needs_present,
1256            last_input_timestamp,
1257            last_input_was_keyboard: false,
1258            refreshing: false,
1259            activation_observers: SubscriberSet::new(),
1260            focus: None,
1261            focus_enabled: true,
1262            pending_input: None,
1263            pending_modifier: ModifierState::default(),
1264            pending_input_observers: SubscriberSet::new(),
1265            prompt: None,
1266            client_inset: None,
1267            image_cache_stack: Vec::new(),
1268            #[cfg(any(feature = "inspector", debug_assertions))]
1269            inspector: None,
1270        })
1271    }
1272
1273    pub(crate) fn new_focus_listener(
1274        &self,
1275        value: AnyWindowFocusListener,
1276    ) -> (Subscription, impl FnOnce() + use<>) {
1277        self.focus_listeners.insert((), value)
1278    }
1279}
1280
1281#[derive(Clone, Debug, Default, PartialEq, Eq)]
1282pub(crate) struct DispatchEventResult {
1283    pub propagate: bool,
1284    pub default_prevented: bool,
1285}
1286
1287/// Indicates which region of the window is visible. Content falling outside of this mask will not be
1288/// rendered. Currently, only rectangular content masks are supported, but we give the mask its own type
1289/// to leave room to support more complex shapes in the future.
1290#[derive(Clone, Debug, Default, PartialEq, Eq)]
1291#[repr(C)]
1292pub struct ContentMask<P: Clone + Debug + Default + PartialEq> {
1293    /// The bounds
1294    pub bounds: Bounds<P>,
1295}
1296
1297impl ContentMask<Pixels> {
1298    /// Scale the content mask's pixel units by the given scaling factor.
1299    pub fn scale(&self, factor: f32) -> ContentMask<ScaledPixels> {
1300        ContentMask {
1301            bounds: self.bounds.scale(factor),
1302        }
1303    }
1304
1305    /// Intersect the content mask with the given content mask.
1306    pub fn intersect(&self, other: &Self) -> Self {
1307        let bounds = self.bounds.intersect(&other.bounds);
1308        ContentMask { bounds }
1309    }
1310}
1311
1312impl Window {
1313    fn mark_view_dirty(&mut self, view_id: EntityId) {
1314        // Mark ancestor views as dirty. If already in the `dirty_views` set, then all its ancestors
1315        // should already be dirty.
1316        for view_id in self
1317            .rendered_frame
1318            .dispatch_tree
1319            .view_path(view_id)
1320            .into_iter()
1321            .rev()
1322        {
1323            if !self.dirty_views.insert(view_id) {
1324                break;
1325            }
1326        }
1327    }
1328
1329    /// Registers a callback to be invoked when the window appearance changes.
1330    pub fn observe_window_appearance(
1331        &self,
1332        mut callback: impl FnMut(&mut Window, &mut App) + 'static,
1333    ) -> Subscription {
1334        let (subscription, activate) = self.appearance_observers.insert(
1335            (),
1336            Box::new(move |window, cx| {
1337                callback(window, cx);
1338                true
1339            }),
1340        );
1341        activate();
1342        subscription
1343    }
1344
1345    /// Replaces the root entity of the window with a new one.
1346    pub fn replace_root<E>(
1347        &mut self,
1348        cx: &mut App,
1349        build_view: impl FnOnce(&mut Window, &mut Context<E>) -> E,
1350    ) -> Entity<E>
1351    where
1352        E: 'static + Render,
1353    {
1354        let view = cx.new(|cx| build_view(self, cx));
1355        self.root = Some(view.clone().into());
1356        self.refresh();
1357        view
1358    }
1359
1360    /// Returns the root entity of the window, if it has one.
1361    pub fn root<E>(&self) -> Option<Option<Entity<E>>>
1362    where
1363        E: 'static + Render,
1364    {
1365        self.root
1366            .as_ref()
1367            .map(|view| view.clone().downcast::<E>().ok())
1368    }
1369
1370    /// Obtain a handle to the window that belongs to this context.
1371    pub fn window_handle(&self) -> AnyWindowHandle {
1372        self.handle
1373    }
1374
1375    /// Mark the window as dirty, scheduling it to be redrawn on the next frame.
1376    pub fn refresh(&mut self) {
1377        if self.invalidator.not_drawing() {
1378            self.refreshing = true;
1379            self.invalidator.set_dirty(true);
1380        }
1381    }
1382
1383    /// Close this window.
1384    pub fn remove_window(&mut self) {
1385        self.removed = true;
1386    }
1387
1388    /// Obtain the currently focused [`FocusHandle`]. If no elements are focused, returns `None`.
1389    pub fn focused(&self, cx: &App) -> Option<FocusHandle> {
1390        self.focus
1391            .and_then(|id| FocusHandle::for_id(id, &cx.focus_handles))
1392    }
1393
1394    /// Move focus to the element associated with the given [`FocusHandle`].
1395    pub fn focus(&mut self, handle: &FocusHandle) {
1396        if !self.focus_enabled || self.focus == Some(handle.id) {
1397            return;
1398        }
1399
1400        self.focus = Some(handle.id);
1401        self.clear_pending_keystrokes();
1402        self.refresh();
1403    }
1404
1405    /// Remove focus from all elements within this context's window.
1406    pub fn blur(&mut self) {
1407        if !self.focus_enabled {
1408            return;
1409        }
1410
1411        self.focus = None;
1412        self.refresh();
1413    }
1414
1415    /// Blur the window and don't allow anything in it to be focused again.
1416    pub fn disable_focus(&mut self) {
1417        self.blur();
1418        self.focus_enabled = false;
1419    }
1420
1421    /// Move focus to next tab stop.
1422    pub fn focus_next(&mut self) {
1423        if !self.focus_enabled {
1424            return;
1425        }
1426
1427        if let Some(handle) = self.rendered_frame.tab_stops.next(self.focus.as_ref()) {
1428            self.focus(&handle)
1429        }
1430    }
1431
1432    /// Move focus to previous tab stop.
1433    pub fn focus_prev(&mut self) {
1434        if !self.focus_enabled {
1435            return;
1436        }
1437
1438        if let Some(handle) = self.rendered_frame.tab_stops.prev(self.focus.as_ref()) {
1439            self.focus(&handle)
1440        }
1441    }
1442
1443    /// Accessor for the text system.
1444    pub fn text_system(&self) -> &Arc<WindowTextSystem> {
1445        &self.text_system
1446    }
1447
1448    /// The current text style. Which is composed of all the style refinements provided to `with_text_style`.
1449    pub fn text_style(&self) -> TextStyle {
1450        let mut style = TextStyle::default();
1451        for refinement in &self.text_style_stack {
1452            style.refine(refinement);
1453        }
1454        style
1455    }
1456
1457    /// Check if the platform window is maximized
1458    /// On some platforms (namely Windows) this is different than the bounds being the size of the display
1459    pub fn is_maximized(&self) -> bool {
1460        self.platform_window.is_maximized()
1461    }
1462
1463    /// request a certain window decoration (Wayland)
1464    pub fn request_decorations(&self, decorations: WindowDecorations) {
1465        self.platform_window.request_decorations(decorations);
1466    }
1467
1468    /// Start a window resize operation (Wayland)
1469    pub fn start_window_resize(&self, edge: ResizeEdge) {
1470        self.platform_window.start_window_resize(edge);
1471    }
1472
1473    /// Return the `WindowBounds` to indicate that how a window should be opened
1474    /// after it has been closed
1475    pub fn window_bounds(&self) -> WindowBounds {
1476        self.platform_window.window_bounds()
1477    }
1478
1479    /// Return the `WindowBounds` excluding insets (Wayland and X11)
1480    pub fn inner_window_bounds(&self) -> WindowBounds {
1481        self.platform_window.inner_window_bounds()
1482    }
1483
1484    /// Dispatch the given action on the currently focused element.
1485    pub fn dispatch_action(&mut self, action: Box<dyn Action>, cx: &mut App) {
1486        let focus_id = self.focused(cx).map(|handle| handle.id);
1487
1488        let window = self.handle;
1489        cx.defer(move |cx| {
1490            window
1491                .update(cx, |_, window, cx| {
1492                    let node_id = window.focus_node_id_in_rendered_frame(focus_id);
1493                    window.dispatch_action_on_node(node_id, action.as_ref(), cx);
1494                })
1495                .log_err();
1496        })
1497    }
1498
1499    pub(crate) fn dispatch_keystroke_observers(
1500        &mut self,
1501        event: &dyn Any,
1502        action: Option<Box<dyn Action>>,
1503        context_stack: Vec<KeyContext>,
1504        cx: &mut App,
1505    ) {
1506        let Some(key_down_event) = event.downcast_ref::<KeyDownEvent>() else {
1507            return;
1508        };
1509
1510        cx.keystroke_observers.clone().retain(&(), move |callback| {
1511            (callback)(
1512                &KeystrokeEvent {
1513                    keystroke: key_down_event.keystroke.clone(),
1514                    action: action.as_ref().map(|action| action.boxed_clone()),
1515                    context_stack: context_stack.clone(),
1516                },
1517                self,
1518                cx,
1519            )
1520        });
1521    }
1522
1523    pub(crate) fn dispatch_keystroke_interceptors(
1524        &mut self,
1525        event: &dyn Any,
1526        context_stack: Vec<KeyContext>,
1527        cx: &mut App,
1528    ) {
1529        let Some(key_down_event) = event.downcast_ref::<KeyDownEvent>() else {
1530            return;
1531        };
1532
1533        cx.keystroke_interceptors
1534            .clone()
1535            .retain(&(), move |callback| {
1536                (callback)(
1537                    &KeystrokeEvent {
1538                        keystroke: key_down_event.keystroke.clone(),
1539                        action: None,
1540                        context_stack: context_stack.clone(),
1541                    },
1542                    self,
1543                    cx,
1544                )
1545            });
1546    }
1547
1548    /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
1549    /// that are currently on the stack to be returned to the app.
1550    pub fn defer(&self, cx: &mut App, f: impl FnOnce(&mut Window, &mut App) + 'static) {
1551        let handle = self.handle;
1552        cx.defer(move |cx| {
1553            handle.update(cx, |_, window, cx| f(window, cx)).ok();
1554        });
1555    }
1556
1557    /// Subscribe to events emitted by a entity.
1558    /// The entity to which you're subscribing must implement the [`EventEmitter`] trait.
1559    /// The callback will be invoked a handle to the emitting entity, the event, and a window context for the current window.
1560    pub fn observe<T: 'static>(
1561        &mut self,
1562        observed: &Entity<T>,
1563        cx: &mut App,
1564        mut on_notify: impl FnMut(Entity<T>, &mut Window, &mut App) + 'static,
1565    ) -> Subscription {
1566        let entity_id = observed.entity_id();
1567        let observed = observed.downgrade();
1568        let window_handle = self.handle;
1569        cx.new_observer(
1570            entity_id,
1571            Box::new(move |cx| {
1572                window_handle
1573                    .update(cx, |_, window, cx| {
1574                        if let Some(handle) = observed.upgrade() {
1575                            on_notify(handle, window, cx);
1576                            true
1577                        } else {
1578                            false
1579                        }
1580                    })
1581                    .unwrap_or(false)
1582            }),
1583        )
1584    }
1585
1586    /// Subscribe to events emitted by a entity.
1587    /// The entity to which you're subscribing must implement the [`EventEmitter`] trait.
1588    /// The callback will be invoked a handle to the emitting entity, the event, and a window context for the current window.
1589    pub fn subscribe<Emitter, Evt>(
1590        &mut self,
1591        entity: &Entity<Emitter>,
1592        cx: &mut App,
1593        mut on_event: impl FnMut(Entity<Emitter>, &Evt, &mut Window, &mut App) + 'static,
1594    ) -> Subscription
1595    where
1596        Emitter: EventEmitter<Evt>,
1597        Evt: 'static,
1598    {
1599        let entity_id = entity.entity_id();
1600        let handle = entity.downgrade();
1601        let window_handle = self.handle;
1602        cx.new_subscription(
1603            entity_id,
1604            (
1605                TypeId::of::<Evt>(),
1606                Box::new(move |event, cx| {
1607                    window_handle
1608                        .update(cx, |_, window, cx| {
1609                            if let Some(entity) = handle.upgrade() {
1610                                let event = event.downcast_ref().expect("invalid event type");
1611                                on_event(entity, event, window, cx);
1612                                true
1613                            } else {
1614                                false
1615                            }
1616                        })
1617                        .unwrap_or(false)
1618                }),
1619            ),
1620        )
1621    }
1622
1623    /// Register a callback to be invoked when the given `Entity` is released.
1624    pub fn observe_release<T>(
1625        &self,
1626        entity: &Entity<T>,
1627        cx: &mut App,
1628        mut on_release: impl FnOnce(&mut T, &mut Window, &mut App) + 'static,
1629    ) -> Subscription
1630    where
1631        T: 'static,
1632    {
1633        let entity_id = entity.entity_id();
1634        let window_handle = self.handle;
1635        let (subscription, activate) = cx.release_listeners.insert(
1636            entity_id,
1637            Box::new(move |entity, cx| {
1638                let entity = entity.downcast_mut().expect("invalid entity type");
1639                let _ = window_handle.update(cx, |_, window, cx| on_release(entity, window, cx));
1640            }),
1641        );
1642        activate();
1643        subscription
1644    }
1645
1646    /// Creates an [`AsyncWindowContext`], which has a static lifetime and can be held across
1647    /// await points in async code.
1648    pub fn to_async(&self, cx: &App) -> AsyncWindowContext {
1649        AsyncWindowContext::new_context(cx.to_async(), self.handle)
1650    }
1651
1652    /// Schedule the given closure to be run directly after the current frame is rendered.
1653    pub fn on_next_frame(&self, callback: impl FnOnce(&mut Window, &mut App) + 'static) {
1654        RefCell::borrow_mut(&self.next_frame_callbacks).push(Box::new(callback));
1655    }
1656
1657    /// Schedule a frame to be drawn on the next animation frame.
1658    ///
1659    /// This is useful for elements that need to animate continuously, such as a video player or an animated GIF.
1660    /// It will cause the window to redraw on the next frame, even if no other changes have occurred.
1661    ///
1662    /// If called from within a view, it will notify that view on the next frame. Otherwise, it will refresh the entire window.
1663    pub fn request_animation_frame(&self) {
1664        let entity = self.current_view();
1665        self.on_next_frame(move |_, cx| cx.notify(entity));
1666    }
1667
1668    /// Spawn the future returned by the given closure on the application thread pool.
1669    /// The closure is provided a handle to the current window and an `AsyncWindowContext` for
1670    /// use within your future.
1671    #[track_caller]
1672    pub fn spawn<AsyncFn, R>(&self, cx: &App, f: AsyncFn) -> Task<R>
1673    where
1674        R: 'static,
1675        AsyncFn: AsyncFnOnce(&mut AsyncWindowContext) -> R + 'static,
1676    {
1677        let handle = self.handle;
1678        cx.spawn(async move |app| {
1679            let mut async_window_cx = AsyncWindowContext::new_context(app.clone(), handle);
1680            f(&mut async_window_cx).await
1681        })
1682    }
1683
1684    fn bounds_changed(&mut self, cx: &mut App) {
1685        self.scale_factor = self.platform_window.scale_factor();
1686        self.viewport_size = self.platform_window.content_size();
1687        self.display_id = self.platform_window.display().map(|display| display.id());
1688
1689        self.refresh();
1690
1691        self.bounds_observers
1692            .clone()
1693            .retain(&(), |callback| callback(self, cx));
1694    }
1695
1696    /// Returns the bounds of the current window in the global coordinate space, which could span across multiple displays.
1697    pub fn bounds(&self) -> Bounds<Pixels> {
1698        self.platform_window.bounds()
1699    }
1700
1701    /// Set the content size of the window.
1702    pub fn resize(&mut self, size: Size<Pixels>) {
1703        self.platform_window.resize(size);
1704    }
1705
1706    /// Returns whether or not the window is currently fullscreen
1707    pub fn is_fullscreen(&self) -> bool {
1708        self.platform_window.is_fullscreen()
1709    }
1710
1711    pub(crate) fn appearance_changed(&mut self, cx: &mut App) {
1712        self.appearance = self.platform_window.appearance();
1713
1714        self.appearance_observers
1715            .clone()
1716            .retain(&(), |callback| callback(self, cx));
1717    }
1718
1719    /// Returns the appearance of the current window.
1720    pub fn appearance(&self) -> WindowAppearance {
1721        self.appearance
1722    }
1723
1724    /// Returns the size of the drawable area within the window.
1725    pub fn viewport_size(&self) -> Size<Pixels> {
1726        self.viewport_size
1727    }
1728
1729    /// Returns whether this window is focused by the operating system (receiving key events).
1730    pub fn is_window_active(&self) -> bool {
1731        self.active.get()
1732    }
1733
1734    /// Returns whether this window is considered to be the window
1735    /// that currently owns the mouse cursor.
1736    /// On mac, this is equivalent to `is_window_active`.
1737    pub fn is_window_hovered(&self) -> bool {
1738        if cfg!(any(
1739            target_os = "windows",
1740            target_os = "linux",
1741            target_os = "freebsd"
1742        )) {
1743            self.hovered.get()
1744        } else {
1745            self.is_window_active()
1746        }
1747    }
1748
1749    /// Toggle zoom on the window.
1750    pub fn zoom_window(&self) {
1751        self.platform_window.zoom();
1752    }
1753
1754    /// Opens the native title bar context menu, useful when implementing client side decorations (Wayland and X11)
1755    pub fn show_window_menu(&self, position: Point<Pixels>) {
1756        self.platform_window.show_window_menu(position)
1757    }
1758
1759    /// Tells the compositor to take control of window movement (Wayland and X11)
1760    ///
1761    /// Events may not be received during a move operation.
1762    pub fn start_window_move(&self) {
1763        self.platform_window.start_window_move()
1764    }
1765
1766    /// When using client side decorations, set this to the width of the invisible decorations (Wayland and X11)
1767    pub fn set_client_inset(&mut self, inset: Pixels) {
1768        self.client_inset = Some(inset);
1769        self.platform_window.set_client_inset(inset);
1770    }
1771
1772    /// Returns the client_inset value by [`Self::set_client_inset`].
1773    pub fn client_inset(&self) -> Option<Pixels> {
1774        self.client_inset
1775    }
1776
1777    /// Returns whether the title bar window controls need to be rendered by the application (Wayland and X11)
1778    pub fn window_decorations(&self) -> Decorations {
1779        self.platform_window.window_decorations()
1780    }
1781
1782    /// Returns which window controls are currently visible (Wayland)
1783    pub fn window_controls(&self) -> WindowControls {
1784        self.platform_window.window_controls()
1785    }
1786
1787    /// Updates the window's title at the platform level.
1788    pub fn set_window_title(&mut self, title: &str) {
1789        self.platform_window.set_title(title);
1790    }
1791
1792    /// Sets the application identifier.
1793    pub fn set_app_id(&mut self, app_id: &str) {
1794        self.platform_window.set_app_id(app_id);
1795    }
1796
1797    /// Sets the window background appearance.
1798    pub fn set_background_appearance(&self, background_appearance: WindowBackgroundAppearance) {
1799        self.platform_window
1800            .set_background_appearance(background_appearance);
1801    }
1802
1803    /// Mark the window as dirty at the platform level.
1804    pub fn set_window_edited(&mut self, edited: bool) {
1805        self.platform_window.set_edited(edited);
1806    }
1807
1808    /// Determine the display on which the window is visible.
1809    pub fn display(&self, cx: &App) -> Option<Rc<dyn PlatformDisplay>> {
1810        cx.platform
1811            .displays()
1812            .into_iter()
1813            .find(|display| Some(display.id()) == self.display_id)
1814    }
1815
1816    /// Show the platform character palette.
1817    pub fn show_character_palette(&self) {
1818        self.platform_window.show_character_palette();
1819    }
1820
1821    /// The scale factor of the display associated with the window. For example, it could
1822    /// return 2.0 for a "retina" display, indicating that each logical pixel should actually
1823    /// be rendered as two pixels on screen.
1824    pub fn scale_factor(&self) -> f32 {
1825        self.scale_factor
1826    }
1827
1828    /// The size of an em for the base font of the application. Adjusting this value allows the
1829    /// UI to scale, just like zooming a web page.
1830    pub fn rem_size(&self) -> Pixels {
1831        self.rem_size_override_stack
1832            .last()
1833            .copied()
1834            .unwrap_or(self.rem_size)
1835    }
1836
1837    /// Sets the size of an em for the base font of the application. Adjusting this value allows the
1838    /// UI to scale, just like zooming a web page.
1839    pub fn set_rem_size(&mut self, rem_size: impl Into<Pixels>) {
1840        self.rem_size = rem_size.into();
1841    }
1842
1843    /// Acquire a globally unique identifier for the given ElementId.
1844    /// Only valid for the duration of the provided closure.
1845    pub fn with_global_id<R>(
1846        &mut self,
1847        element_id: ElementId,
1848        f: impl FnOnce(&GlobalElementId, &mut Self) -> R,
1849    ) -> R {
1850        self.element_id_stack.push(element_id);
1851        let global_id = GlobalElementId(self.element_id_stack.clone());
1852        let result = f(&global_id, self);
1853        self.element_id_stack.pop();
1854        result
1855    }
1856
1857    /// Executes the provided function with the specified rem size.
1858    ///
1859    /// This method must only be called as part of element drawing.
1860    pub fn with_rem_size<F, R>(&mut self, rem_size: Option<impl Into<Pixels>>, f: F) -> R
1861    where
1862        F: FnOnce(&mut Self) -> R,
1863    {
1864        self.invalidator.debug_assert_paint_or_prepaint();
1865
1866        if let Some(rem_size) = rem_size {
1867            self.rem_size_override_stack.push(rem_size.into());
1868            let result = f(self);
1869            self.rem_size_override_stack.pop();
1870            result
1871        } else {
1872            f(self)
1873        }
1874    }
1875
1876    /// The line height associated with the current text style.
1877    pub fn line_height(&self) -> Pixels {
1878        self.text_style().line_height_in_pixels(self.rem_size())
1879    }
1880
1881    /// Call to prevent the default action of an event. Currently only used to prevent
1882    /// parent elements from becoming focused on mouse down.
1883    pub fn prevent_default(&mut self) {
1884        self.default_prevented = true;
1885    }
1886
1887    /// Obtain whether default has been prevented for the event currently being dispatched.
1888    pub fn default_prevented(&self) -> bool {
1889        self.default_prevented
1890    }
1891
1892    /// Determine whether the given action is available along the dispatch path to the currently focused element.
1893    pub fn is_action_available(&self, action: &dyn Action, cx: &mut App) -> bool {
1894        let node_id =
1895            self.focus_node_id_in_rendered_frame(self.focused(cx).map(|handle| handle.id));
1896        self.rendered_frame
1897            .dispatch_tree
1898            .is_action_available(action, node_id)
1899    }
1900
1901    /// The position of the mouse relative to the window.
1902    pub fn mouse_position(&self) -> Point<Pixels> {
1903        self.mouse_position
1904    }
1905
1906    /// The current state of the keyboard's modifiers
1907    pub fn modifiers(&self) -> Modifiers {
1908        self.modifiers
1909    }
1910
1911    /// Returns true if the last input event was keyboard-based (key press, tab navigation, etc.)
1912    /// This is used for focus-visible styling to show focus indicators only for keyboard navigation.
1913    pub fn last_input_was_keyboard(&self) -> bool {
1914        self.last_input_was_keyboard
1915    }
1916
1917    /// The current state of the keyboard's capslock
1918    pub fn capslock(&self) -> Capslock {
1919        self.capslock
1920    }
1921
1922    fn complete_frame(&self) {
1923        self.platform_window.completed_frame();
1924    }
1925
1926    /// Produces a new frame and assigns it to `rendered_frame`. To actually show
1927    /// the contents of the new [`Scene`], use [`Self::present`].
1928    #[profiling::function]
1929    pub fn draw(&mut self, cx: &mut App) -> ArenaClearNeeded {
1930        self.invalidate_entities();
1931        cx.entities.clear_accessed();
1932        debug_assert!(self.rendered_entity_stack.is_empty());
1933        self.invalidator.set_dirty(false);
1934        self.requested_autoscroll = None;
1935
1936        // Restore the previously-used input handler.
1937        if let Some(input_handler) = self.platform_window.take_input_handler() {
1938            self.rendered_frame.input_handlers.push(Some(input_handler));
1939        }
1940        self.draw_roots(cx);
1941        self.dirty_views.clear();
1942        self.next_frame.window_active = self.active.get();
1943
1944        // Register requested input handler with the platform window.
1945        if let Some(input_handler) = self.next_frame.input_handlers.pop() {
1946            self.platform_window
1947                .set_input_handler(input_handler.unwrap());
1948        }
1949
1950        self.layout_engine.as_mut().unwrap().clear();
1951        self.text_system().finish_frame();
1952        self.next_frame.finish(&mut self.rendered_frame);
1953
1954        self.invalidator.set_phase(DrawPhase::Focus);
1955        let previous_focus_path = self.rendered_frame.focus_path();
1956        let previous_window_active = self.rendered_frame.window_active;
1957        mem::swap(&mut self.rendered_frame, &mut self.next_frame);
1958        self.next_frame.clear();
1959        let current_focus_path = self.rendered_frame.focus_path();
1960        let current_window_active = self.rendered_frame.window_active;
1961
1962        if previous_focus_path != current_focus_path
1963            || previous_window_active != current_window_active
1964        {
1965            if !previous_focus_path.is_empty() && current_focus_path.is_empty() {
1966                self.focus_lost_listeners
1967                    .clone()
1968                    .retain(&(), |listener| listener(self, cx));
1969            }
1970
1971            let event = WindowFocusEvent {
1972                previous_focus_path: if previous_window_active {
1973                    previous_focus_path
1974                } else {
1975                    Default::default()
1976                },
1977                current_focus_path: if current_window_active {
1978                    current_focus_path
1979                } else {
1980                    Default::default()
1981                },
1982            };
1983            self.focus_listeners
1984                .clone()
1985                .retain(&(), |listener| listener(&event, self, cx));
1986        }
1987
1988        debug_assert!(self.rendered_entity_stack.is_empty());
1989        self.record_entities_accessed(cx);
1990        self.reset_cursor_style(cx);
1991        self.refreshing = false;
1992        self.invalidator.set_phase(DrawPhase::None);
1993        self.needs_present.set(true);
1994
1995        ArenaClearNeeded
1996    }
1997
1998    fn record_entities_accessed(&mut self, cx: &mut App) {
1999        let mut entities_ref = cx.entities.accessed_entities.borrow_mut();
2000        let mut entities = mem::take(entities_ref.deref_mut());
2001        drop(entities_ref);
2002        let handle = self.handle;
2003        cx.record_entities_accessed(
2004            handle,
2005            // Try moving window invalidator into the Window
2006            self.invalidator.clone(),
2007            &entities,
2008        );
2009        let mut entities_ref = cx.entities.accessed_entities.borrow_mut();
2010        mem::swap(&mut entities, entities_ref.deref_mut());
2011    }
2012
2013    fn invalidate_entities(&mut self) {
2014        let mut views = self.invalidator.take_views();
2015        for entity in views.drain() {
2016            self.mark_view_dirty(entity);
2017        }
2018        self.invalidator.replace_views(views);
2019    }
2020
2021    #[profiling::function]
2022    fn present(&self) {
2023        self.platform_window.draw(&self.rendered_frame.scene);
2024        self.needs_present.set(false);
2025        profiling::finish_frame!();
2026    }
2027
2028    fn draw_roots(&mut self, cx: &mut App) {
2029        self.invalidator.set_phase(DrawPhase::Prepaint);
2030        self.tooltip_bounds.take();
2031
2032        let _inspector_width: Pixels = rems(30.0).to_pixels(self.rem_size());
2033        let root_size = {
2034            #[cfg(any(feature = "inspector", debug_assertions))]
2035            {
2036                if self.inspector.is_some() {
2037                    let mut size = self.viewport_size;
2038                    size.width = (size.width - _inspector_width).max(px(0.0));
2039                    size
2040                } else {
2041                    self.viewport_size
2042                }
2043            }
2044            #[cfg(not(any(feature = "inspector", debug_assertions)))]
2045            {
2046                self.viewport_size
2047            }
2048        };
2049
2050        // Layout all root elements.
2051        let mut root_element = self.root.as_ref().unwrap().clone().into_any();
2052        root_element.prepaint_as_root(Point::default(), root_size.into(), self, cx);
2053
2054        #[cfg(any(feature = "inspector", debug_assertions))]
2055        let inspector_element = self.prepaint_inspector(_inspector_width, cx);
2056
2057        let mut sorted_deferred_draws =
2058            (0..self.next_frame.deferred_draws.len()).collect::<SmallVec<[_; 8]>>();
2059        sorted_deferred_draws.sort_by_key(|ix| self.next_frame.deferred_draws[*ix].priority);
2060        self.prepaint_deferred_draws(&sorted_deferred_draws, cx);
2061
2062        let mut prompt_element = None;
2063        let mut active_drag_element = None;
2064        let mut tooltip_element = None;
2065        if let Some(prompt) = self.prompt.take() {
2066            let mut element = prompt.view.any_view().into_any();
2067            element.prepaint_as_root(Point::default(), root_size.into(), self, cx);
2068            prompt_element = Some(element);
2069            self.prompt = Some(prompt);
2070        } else if let Some(active_drag) = cx.active_drag.take() {
2071            let mut element = active_drag.view.clone().into_any();
2072            let offset = self.mouse_position() - active_drag.cursor_offset;
2073            element.prepaint_as_root(offset, AvailableSpace::min_size(), self, cx);
2074            active_drag_element = Some(element);
2075            cx.active_drag = Some(active_drag);
2076        } else {
2077            tooltip_element = self.prepaint_tooltip(cx);
2078        }
2079
2080        self.mouse_hit_test = self.next_frame.hit_test(self.mouse_position);
2081
2082        // Now actually paint the elements.
2083        self.invalidator.set_phase(DrawPhase::Paint);
2084        root_element.paint(self, cx);
2085
2086        #[cfg(any(feature = "inspector", debug_assertions))]
2087        self.paint_inspector(inspector_element, cx);
2088
2089        self.paint_deferred_draws(&sorted_deferred_draws, cx);
2090
2091        if let Some(mut prompt_element) = prompt_element {
2092            prompt_element.paint(self, cx);
2093        } else if let Some(mut drag_element) = active_drag_element {
2094            drag_element.paint(self, cx);
2095        } else if let Some(mut tooltip_element) = tooltip_element {
2096            tooltip_element.paint(self, cx);
2097        }
2098
2099        #[cfg(any(feature = "inspector", debug_assertions))]
2100        self.paint_inspector_hitbox(cx);
2101    }
2102
2103    fn prepaint_tooltip(&mut self, cx: &mut App) -> Option<AnyElement> {
2104        // Use indexing instead of iteration to avoid borrowing self for the duration of the loop.
2105        for tooltip_request_index in (0..self.next_frame.tooltip_requests.len()).rev() {
2106            let Some(Some(tooltip_request)) = self
2107                .next_frame
2108                .tooltip_requests
2109                .get(tooltip_request_index)
2110                .cloned()
2111            else {
2112                log::error!("Unexpectedly absent TooltipRequest");
2113                continue;
2114            };
2115            let mut element = tooltip_request.tooltip.view.clone().into_any();
2116            let mouse_position = tooltip_request.tooltip.mouse_position;
2117            let tooltip_size = element.layout_as_root(AvailableSpace::min_size(), self, cx);
2118
2119            let mut tooltip_bounds =
2120                Bounds::new(mouse_position + point(px(1.), px(1.)), tooltip_size);
2121            let window_bounds = Bounds {
2122                origin: Point::default(),
2123                size: self.viewport_size(),
2124            };
2125
2126            if tooltip_bounds.right() > window_bounds.right() {
2127                let new_x = mouse_position.x - tooltip_bounds.size.width - px(1.);
2128                if new_x >= Pixels::ZERO {
2129                    tooltip_bounds.origin.x = new_x;
2130                } else {
2131                    tooltip_bounds.origin.x = cmp::max(
2132                        Pixels::ZERO,
2133                        tooltip_bounds.origin.x - tooltip_bounds.right() - window_bounds.right(),
2134                    );
2135                }
2136            }
2137
2138            if tooltip_bounds.bottom() > window_bounds.bottom() {
2139                let new_y = mouse_position.y - tooltip_bounds.size.height - px(1.);
2140                if new_y >= Pixels::ZERO {
2141                    tooltip_bounds.origin.y = new_y;
2142                } else {
2143                    tooltip_bounds.origin.y = cmp::max(
2144                        Pixels::ZERO,
2145                        tooltip_bounds.origin.y - tooltip_bounds.bottom() - window_bounds.bottom(),
2146                    );
2147                }
2148            }
2149
2150            // It's possible for an element to have an active tooltip while not being painted (e.g.
2151            // via the `visible_on_hover` method). Since mouse listeners are not active in this
2152            // case, instead update the tooltip's visibility here.
2153            let is_visible =
2154                (tooltip_request.tooltip.check_visible_and_update)(tooltip_bounds, self, cx);
2155            if !is_visible {
2156                continue;
2157            }
2158
2159            self.with_absolute_element_offset(tooltip_bounds.origin, |window| {
2160                element.prepaint(window, cx)
2161            });
2162
2163            self.tooltip_bounds = Some(TooltipBounds {
2164                id: tooltip_request.id,
2165                bounds: tooltip_bounds,
2166            });
2167            return Some(element);
2168        }
2169        None
2170    }
2171
2172    fn prepaint_deferred_draws(&mut self, deferred_draw_indices: &[usize], cx: &mut App) {
2173        assert_eq!(self.element_id_stack.len(), 0);
2174
2175        let mut deferred_draws = mem::take(&mut self.next_frame.deferred_draws);
2176        for deferred_draw_ix in deferred_draw_indices {
2177            let deferred_draw = &mut deferred_draws[*deferred_draw_ix];
2178            self.element_id_stack
2179                .clone_from(&deferred_draw.element_id_stack);
2180            self.text_style_stack
2181                .clone_from(&deferred_draw.text_style_stack);
2182            self.next_frame
2183                .dispatch_tree
2184                .set_active_node(deferred_draw.parent_node);
2185
2186            let prepaint_start = self.prepaint_index();
2187            if let Some(element) = deferred_draw.element.as_mut() {
2188                self.with_rendered_view(deferred_draw.current_view, |window| {
2189                    window.with_absolute_element_offset(deferred_draw.absolute_offset, |window| {
2190                        element.prepaint(window, cx)
2191                    });
2192                })
2193            } else {
2194                self.reuse_prepaint(deferred_draw.prepaint_range.clone());
2195            }
2196            let prepaint_end = self.prepaint_index();
2197            deferred_draw.prepaint_range = prepaint_start..prepaint_end;
2198        }
2199        assert_eq!(
2200            self.next_frame.deferred_draws.len(),
2201            0,
2202            "cannot call defer_draw during deferred drawing"
2203        );
2204        self.next_frame.deferred_draws = deferred_draws;
2205        self.element_id_stack.clear();
2206        self.text_style_stack.clear();
2207    }
2208
2209    fn paint_deferred_draws(&mut self, deferred_draw_indices: &[usize], cx: &mut App) {
2210        assert_eq!(self.element_id_stack.len(), 0);
2211
2212        let mut deferred_draws = mem::take(&mut self.next_frame.deferred_draws);
2213        for deferred_draw_ix in deferred_draw_indices {
2214            let mut deferred_draw = &mut deferred_draws[*deferred_draw_ix];
2215            self.element_id_stack
2216                .clone_from(&deferred_draw.element_id_stack);
2217            self.next_frame
2218                .dispatch_tree
2219                .set_active_node(deferred_draw.parent_node);
2220
2221            let paint_start = self.paint_index();
2222            if let Some(element) = deferred_draw.element.as_mut() {
2223                self.with_rendered_view(deferred_draw.current_view, |window| {
2224                    element.paint(window, cx);
2225                })
2226            } else {
2227                self.reuse_paint(deferred_draw.paint_range.clone());
2228            }
2229            let paint_end = self.paint_index();
2230            deferred_draw.paint_range = paint_start..paint_end;
2231        }
2232        self.next_frame.deferred_draws = deferred_draws;
2233        self.element_id_stack.clear();
2234    }
2235
2236    pub(crate) fn prepaint_index(&self) -> PrepaintStateIndex {
2237        PrepaintStateIndex {
2238            hitboxes_index: self.next_frame.hitboxes.len(),
2239            tooltips_index: self.next_frame.tooltip_requests.len(),
2240            deferred_draws_index: self.next_frame.deferred_draws.len(),
2241            dispatch_tree_index: self.next_frame.dispatch_tree.len(),
2242            accessed_element_states_index: self.next_frame.accessed_element_states.len(),
2243            line_layout_index: self.text_system.layout_index(),
2244        }
2245    }
2246
2247    pub(crate) fn reuse_prepaint(&mut self, range: Range<PrepaintStateIndex>) {
2248        self.next_frame.hitboxes.extend(
2249            self.rendered_frame.hitboxes[range.start.hitboxes_index..range.end.hitboxes_index]
2250                .iter()
2251                .cloned(),
2252        );
2253        self.next_frame.tooltip_requests.extend(
2254            self.rendered_frame.tooltip_requests
2255                [range.start.tooltips_index..range.end.tooltips_index]
2256                .iter_mut()
2257                .map(|request| request.take()),
2258        );
2259        self.next_frame.accessed_element_states.extend(
2260            self.rendered_frame.accessed_element_states[range.start.accessed_element_states_index
2261                ..range.end.accessed_element_states_index]
2262                .iter()
2263                .map(|(id, type_id)| (GlobalElementId(id.0.clone()), *type_id)),
2264        );
2265        self.text_system
2266            .reuse_layouts(range.start.line_layout_index..range.end.line_layout_index);
2267
2268        let reused_subtree = self.next_frame.dispatch_tree.reuse_subtree(
2269            range.start.dispatch_tree_index..range.end.dispatch_tree_index,
2270            &mut self.rendered_frame.dispatch_tree,
2271            self.focus,
2272        );
2273
2274        if reused_subtree.contains_focus() {
2275            self.next_frame.focus = self.focus;
2276        }
2277
2278        self.next_frame.deferred_draws.extend(
2279            self.rendered_frame.deferred_draws
2280                [range.start.deferred_draws_index..range.end.deferred_draws_index]
2281                .iter()
2282                .map(|deferred_draw| DeferredDraw {
2283                    current_view: deferred_draw.current_view,
2284                    parent_node: reused_subtree.refresh_node_id(deferred_draw.parent_node),
2285                    element_id_stack: deferred_draw.element_id_stack.clone(),
2286                    text_style_stack: deferred_draw.text_style_stack.clone(),
2287                    priority: deferred_draw.priority,
2288                    element: None,
2289                    absolute_offset: deferred_draw.absolute_offset,
2290                    prepaint_range: deferred_draw.prepaint_range.clone(),
2291                    paint_range: deferred_draw.paint_range.clone(),
2292                }),
2293        );
2294    }
2295
2296    pub(crate) fn paint_index(&self) -> PaintIndex {
2297        PaintIndex {
2298            scene_index: self.next_frame.scene.len(),
2299            mouse_listeners_index: self.next_frame.mouse_listeners.len(),
2300            input_handlers_index: self.next_frame.input_handlers.len(),
2301            cursor_styles_index: self.next_frame.cursor_styles.len(),
2302            accessed_element_states_index: self.next_frame.accessed_element_states.len(),
2303            tab_handle_index: self.next_frame.tab_stops.paint_index(),
2304            line_layout_index: self.text_system.layout_index(),
2305        }
2306    }
2307
2308    pub(crate) fn reuse_paint(&mut self, range: Range<PaintIndex>) {
2309        self.next_frame.cursor_styles.extend(
2310            self.rendered_frame.cursor_styles
2311                [range.start.cursor_styles_index..range.end.cursor_styles_index]
2312                .iter()
2313                .cloned(),
2314        );
2315        self.next_frame.input_handlers.extend(
2316            self.rendered_frame.input_handlers
2317                [range.start.input_handlers_index..range.end.input_handlers_index]
2318                .iter_mut()
2319                .map(|handler| handler.take()),
2320        );
2321        self.next_frame.mouse_listeners.extend(
2322            self.rendered_frame.mouse_listeners
2323                [range.start.mouse_listeners_index..range.end.mouse_listeners_index]
2324                .iter_mut()
2325                .map(|listener| listener.take()),
2326        );
2327        self.next_frame.accessed_element_states.extend(
2328            self.rendered_frame.accessed_element_states[range.start.accessed_element_states_index
2329                ..range.end.accessed_element_states_index]
2330                .iter()
2331                .map(|(id, type_id)| (GlobalElementId(id.0.clone()), *type_id)),
2332        );
2333        self.next_frame.tab_stops.replay(
2334            &self.rendered_frame.tab_stops.insertion_history
2335                [range.start.tab_handle_index..range.end.tab_handle_index],
2336        );
2337
2338        self.text_system
2339            .reuse_layouts(range.start.line_layout_index..range.end.line_layout_index);
2340        self.next_frame.scene.replay(
2341            range.start.scene_index..range.end.scene_index,
2342            &self.rendered_frame.scene,
2343        );
2344    }
2345
2346    /// Push a text style onto the stack, and call a function with that style active.
2347    /// Use [`Window::text_style`] to get the current, combined text style. This method
2348    /// should only be called as part of element drawing.
2349    pub fn with_text_style<F, R>(&mut self, style: Option<TextStyleRefinement>, f: F) -> R
2350    where
2351        F: FnOnce(&mut Self) -> R,
2352    {
2353        self.invalidator.debug_assert_paint_or_prepaint();
2354        if let Some(style) = style {
2355            self.text_style_stack.push(style);
2356            let result = f(self);
2357            self.text_style_stack.pop();
2358            result
2359        } else {
2360            f(self)
2361        }
2362    }
2363
2364    /// Updates the cursor style at the platform level. This method should only be called
2365    /// during the prepaint phase of element drawing.
2366    pub fn set_cursor_style(&mut self, style: CursorStyle, hitbox: &Hitbox) {
2367        self.invalidator.debug_assert_paint();
2368        self.next_frame.cursor_styles.push(CursorStyleRequest {
2369            hitbox_id: Some(hitbox.id),
2370            style,
2371        });
2372    }
2373
2374    /// Updates the cursor style for the entire window at the platform level. A cursor
2375    /// style using this method will have precedence over any cursor style set using
2376    /// `set_cursor_style`. This method should only be called during the prepaint
2377    /// phase of element drawing.
2378    pub fn set_window_cursor_style(&mut self, style: CursorStyle) {
2379        self.invalidator.debug_assert_paint();
2380        self.next_frame.cursor_styles.push(CursorStyleRequest {
2381            hitbox_id: None,
2382            style,
2383        })
2384    }
2385
2386    /// Sets a tooltip to be rendered for the upcoming frame. This method should only be called
2387    /// during the paint phase of element drawing.
2388    pub fn set_tooltip(&mut self, tooltip: AnyTooltip) -> TooltipId {
2389        self.invalidator.debug_assert_prepaint();
2390        let id = TooltipId(post_inc(&mut self.next_tooltip_id.0));
2391        self.next_frame
2392            .tooltip_requests
2393            .push(Some(TooltipRequest { id, tooltip }));
2394        id
2395    }
2396
2397    /// Invoke the given function with the given content mask after intersecting it
2398    /// with the current mask. This method should only be called during element drawing.
2399    pub fn with_content_mask<R>(
2400        &mut self,
2401        mask: Option<ContentMask<Pixels>>,
2402        f: impl FnOnce(&mut Self) -> R,
2403    ) -> R {
2404        self.invalidator.debug_assert_paint_or_prepaint();
2405        if let Some(mask) = mask {
2406            let mask = mask.intersect(&self.content_mask());
2407            self.content_mask_stack.push(mask);
2408            let result = f(self);
2409            self.content_mask_stack.pop();
2410            result
2411        } else {
2412            f(self)
2413        }
2414    }
2415
2416    /// Updates the global element offset relative to the current offset. This is used to implement
2417    /// scrolling. This method should only be called during the prepaint phase of element drawing.
2418    pub fn with_element_offset<R>(
2419        &mut self,
2420        offset: Point<Pixels>,
2421        f: impl FnOnce(&mut Self) -> R,
2422    ) -> R {
2423        self.invalidator.debug_assert_prepaint();
2424
2425        if offset.is_zero() {
2426            return f(self);
2427        };
2428
2429        let abs_offset = self.element_offset() + offset;
2430        self.with_absolute_element_offset(abs_offset, f)
2431    }
2432
2433    /// Updates the global element offset based on the given offset. This is used to implement
2434    /// drag handles and other manual painting of elements. This method should only be called during
2435    /// the prepaint phase of element drawing.
2436    pub fn with_absolute_element_offset<R>(
2437        &mut self,
2438        offset: Point<Pixels>,
2439        f: impl FnOnce(&mut Self) -> R,
2440    ) -> R {
2441        self.invalidator.debug_assert_prepaint();
2442        self.element_offset_stack.push(offset);
2443        let result = f(self);
2444        self.element_offset_stack.pop();
2445        result
2446    }
2447
2448    pub(crate) fn with_element_opacity<R>(
2449        &mut self,
2450        opacity: Option<f32>,
2451        f: impl FnOnce(&mut Self) -> R,
2452    ) -> R {
2453        self.invalidator.debug_assert_paint_or_prepaint();
2454
2455        let Some(opacity) = opacity else {
2456            return f(self);
2457        };
2458
2459        let previous_opacity = self.element_opacity;
2460        self.element_opacity = previous_opacity * opacity;
2461        let result = f(self);
2462        self.element_opacity = previous_opacity;
2463        result
2464    }
2465
2466    /// Perform prepaint on child elements in a "retryable" manner, so that any side effects
2467    /// of prepaints can be discarded before prepainting again. This is used to support autoscroll
2468    /// where we need to prepaint children to detect the autoscroll bounds, then adjust the
2469    /// element offset and prepaint again. See [`crate::List`] for an example. This method should only be
2470    /// called during the prepaint phase of element drawing.
2471    pub fn transact<T, U>(&mut self, f: impl FnOnce(&mut Self) -> Result<T, U>) -> Result<T, U> {
2472        self.invalidator.debug_assert_prepaint();
2473        let index = self.prepaint_index();
2474        let result = f(self);
2475        if result.is_err() {
2476            self.next_frame.hitboxes.truncate(index.hitboxes_index);
2477            self.next_frame
2478                .tooltip_requests
2479                .truncate(index.tooltips_index);
2480            self.next_frame
2481                .deferred_draws
2482                .truncate(index.deferred_draws_index);
2483            self.next_frame
2484                .dispatch_tree
2485                .truncate(index.dispatch_tree_index);
2486            self.next_frame
2487                .accessed_element_states
2488                .truncate(index.accessed_element_states_index);
2489            self.text_system.truncate_layouts(index.line_layout_index);
2490        }
2491        result
2492    }
2493
2494    /// When you call this method during [`Element::prepaint`], containing elements will attempt to
2495    /// scroll to cause the specified bounds to become visible. When they decide to autoscroll, they will call
2496    /// [`Element::prepaint`] again with a new set of bounds. See [`crate::List`] for an example of an element
2497    /// that supports this method being called on the elements it contains. This method should only be
2498    /// called during the prepaint phase of element drawing.
2499    pub fn request_autoscroll(&mut self, bounds: Bounds<Pixels>) {
2500        self.invalidator.debug_assert_prepaint();
2501        self.requested_autoscroll = Some(bounds);
2502    }
2503
2504    /// This method can be called from a containing element such as [`crate::List`] to support the autoscroll behavior
2505    /// described in [`Self::request_autoscroll`].
2506    pub fn take_autoscroll(&mut self) -> Option<Bounds<Pixels>> {
2507        self.invalidator.debug_assert_prepaint();
2508        self.requested_autoscroll.take()
2509    }
2510
2511    /// Asynchronously load an asset, if the asset hasn't finished loading this will return None.
2512    /// Your view will be re-drawn once the asset has finished loading.
2513    ///
2514    /// Note that the multiple calls to this method will only result in one `Asset::load` call at a
2515    /// time.
2516    pub fn use_asset<A: Asset>(&mut self, source: &A::Source, cx: &mut App) -> Option<A::Output> {
2517        let (task, is_first) = cx.fetch_asset::<A>(source);
2518        task.clone().now_or_never().or_else(|| {
2519            if is_first {
2520                let entity_id = self.current_view();
2521                self.spawn(cx, {
2522                    let task = task.clone();
2523                    async move |cx| {
2524                        task.await;
2525
2526                        cx.on_next_frame(move |_, cx| {
2527                            cx.notify(entity_id);
2528                        });
2529                    }
2530                })
2531                .detach();
2532            }
2533
2534            None
2535        })
2536    }
2537
2538    /// Asynchronously load an asset, if the asset hasn't finished loading or doesn't exist this will return None.
2539    /// Your view will not be re-drawn once the asset has finished loading.
2540    ///
2541    /// Note that the multiple calls to this method will only result in one `Asset::load` call at a
2542    /// time.
2543    pub fn get_asset<A: Asset>(&mut self, source: &A::Source, cx: &mut App) -> Option<A::Output> {
2544        let (task, _) = cx.fetch_asset::<A>(source);
2545        task.now_or_never()
2546    }
2547    /// Obtain the current element offset. This method should only be called during the
2548    /// prepaint phase of element drawing.
2549    pub fn element_offset(&self) -> Point<Pixels> {
2550        self.invalidator.debug_assert_prepaint();
2551        self.element_offset_stack
2552            .last()
2553            .copied()
2554            .unwrap_or_default()
2555    }
2556
2557    /// Obtain the current element opacity. This method should only be called during the
2558    /// prepaint phase of element drawing.
2559    #[inline]
2560    pub(crate) fn element_opacity(&self) -> f32 {
2561        self.invalidator.debug_assert_paint_or_prepaint();
2562        self.element_opacity
2563    }
2564
2565    /// Obtain the current content mask. This method should only be called during element drawing.
2566    pub fn content_mask(&self) -> ContentMask<Pixels> {
2567        self.invalidator.debug_assert_paint_or_prepaint();
2568        self.content_mask_stack
2569            .last()
2570            .cloned()
2571            .unwrap_or_else(|| ContentMask {
2572                bounds: Bounds {
2573                    origin: Point::default(),
2574                    size: self.viewport_size,
2575                },
2576            })
2577    }
2578
2579    /// Provide elements in the called function with a new namespace in which their identifiers must be unique.
2580    /// This can be used within a custom element to distinguish multiple sets of child elements.
2581    pub fn with_element_namespace<R>(
2582        &mut self,
2583        element_id: impl Into<ElementId>,
2584        f: impl FnOnce(&mut Self) -> R,
2585    ) -> R {
2586        self.element_id_stack.push(element_id.into());
2587        let result = f(self);
2588        self.element_id_stack.pop();
2589        result
2590    }
2591
2592    /// Use a piece of state that exists as long this element is being rendered in consecutive frames.
2593    pub fn use_keyed_state<S: 'static>(
2594        &mut self,
2595        key: impl Into<ElementId>,
2596        cx: &mut App,
2597        init: impl FnOnce(&mut Self, &mut Context<S>) -> S,
2598    ) -> Entity<S> {
2599        let current_view = self.current_view();
2600        self.with_global_id(key.into(), |global_id, window| {
2601            window.with_element_state(global_id, |state: Option<Entity<S>>, window| {
2602                if let Some(state) = state {
2603                    (state.clone(), state)
2604                } else {
2605                    let new_state = cx.new(|cx| init(window, cx));
2606                    cx.observe(&new_state, move |_, cx| {
2607                        cx.notify(current_view);
2608                    })
2609                    .detach();
2610                    (new_state.clone(), new_state)
2611                }
2612            })
2613        })
2614    }
2615
2616    /// Immediately push an element ID onto the stack. Useful for simplifying IDs in lists
2617    pub fn with_id<R>(&mut self, id: impl Into<ElementId>, f: impl FnOnce(&mut Self) -> R) -> R {
2618        self.with_global_id(id.into(), |_, window| f(window))
2619    }
2620
2621    /// Use a piece of state that exists as long this element is being rendered in consecutive frames, without needing to specify a key
2622    ///
2623    /// NOTE: This method uses the location of the caller to generate an ID for this state.
2624    ///       If this is not sufficient to identify your state (e.g. you're rendering a list item),
2625    ///       you can provide a custom ElementID using the `use_keyed_state` method.
2626    #[track_caller]
2627    pub fn use_state<S: 'static>(
2628        &mut self,
2629        cx: &mut App,
2630        init: impl FnOnce(&mut Self, &mut Context<S>) -> S,
2631    ) -> Entity<S> {
2632        self.use_keyed_state(
2633            ElementId::CodeLocation(*core::panic::Location::caller()),
2634            cx,
2635            init,
2636        )
2637    }
2638
2639    /// Updates or initializes state for an element with the given id that lives across multiple
2640    /// frames. If an element with this ID existed in the rendered frame, its state will be passed
2641    /// to the given closure. The state returned by the closure will be stored so it can be referenced
2642    /// when drawing the next frame. This method should only be called as part of element drawing.
2643    pub fn with_element_state<S, R>(
2644        &mut self,
2645        global_id: &GlobalElementId,
2646        f: impl FnOnce(Option<S>, &mut Self) -> (R, S),
2647    ) -> R
2648    where
2649        S: 'static,
2650    {
2651        self.invalidator.debug_assert_paint_or_prepaint();
2652
2653        let key = (GlobalElementId(global_id.0.clone()), TypeId::of::<S>());
2654        self.next_frame
2655            .accessed_element_states
2656            .push((GlobalElementId(key.0.clone()), TypeId::of::<S>()));
2657
2658        if let Some(any) = self
2659            .next_frame
2660            .element_states
2661            .remove(&key)
2662            .or_else(|| self.rendered_frame.element_states.remove(&key))
2663        {
2664            let ElementStateBox {
2665                inner,
2666                #[cfg(debug_assertions)]
2667                type_name,
2668            } = any;
2669            // Using the extra inner option to avoid needing to reallocate a new box.
2670            let mut state_box = inner
2671                .downcast::<Option<S>>()
2672                .map_err(|_| {
2673                    #[cfg(debug_assertions)]
2674                    {
2675                        anyhow::anyhow!(
2676                            "invalid element state type for id, requested {:?}, actual: {:?}",
2677                            std::any::type_name::<S>(),
2678                            type_name
2679                        )
2680                    }
2681
2682                    #[cfg(not(debug_assertions))]
2683                    {
2684                        anyhow::anyhow!(
2685                            "invalid element state type for id, requested {:?}",
2686                            std::any::type_name::<S>(),
2687                        )
2688                    }
2689                })
2690                .unwrap();
2691
2692            let state = state_box.take().expect(
2693                "reentrant call to with_element_state for the same state type and element id",
2694            );
2695            let (result, state) = f(Some(state), self);
2696            state_box.replace(state);
2697            self.next_frame.element_states.insert(
2698                key,
2699                ElementStateBox {
2700                    inner: state_box,
2701                    #[cfg(debug_assertions)]
2702                    type_name,
2703                },
2704            );
2705            result
2706        } else {
2707            let (result, state) = f(None, self);
2708            self.next_frame.element_states.insert(
2709                key,
2710                ElementStateBox {
2711                    inner: Box::new(Some(state)),
2712                    #[cfg(debug_assertions)]
2713                    type_name: std::any::type_name::<S>(),
2714                },
2715            );
2716            result
2717        }
2718    }
2719
2720    /// A variant of `with_element_state` that allows the element's id to be optional. This is a convenience
2721    /// method for elements where the element id may or may not be assigned. Prefer using `with_element_state`
2722    /// when the element is guaranteed to have an id.
2723    ///
2724    /// The first option means 'no ID provided'
2725    /// The second option means 'not yet initialized'
2726    pub fn with_optional_element_state<S, R>(
2727        &mut self,
2728        global_id: Option<&GlobalElementId>,
2729        f: impl FnOnce(Option<Option<S>>, &mut Self) -> (R, Option<S>),
2730    ) -> R
2731    where
2732        S: 'static,
2733    {
2734        self.invalidator.debug_assert_paint_or_prepaint();
2735
2736        if let Some(global_id) = global_id {
2737            self.with_element_state(global_id, |state, cx| {
2738                let (result, state) = f(Some(state), cx);
2739                let state =
2740                    state.expect("you must return some state when you pass some element id");
2741                (result, state)
2742            })
2743        } else {
2744            let (result, state) = f(None, self);
2745            debug_assert!(
2746                state.is_none(),
2747                "you must not return an element state when passing None for the global id"
2748            );
2749            result
2750        }
2751    }
2752
2753    /// Executes the given closure within the context of a tab group.
2754    #[inline]
2755    pub fn with_tab_group<R>(&mut self, index: Option<isize>, f: impl FnOnce(&mut Self) -> R) -> R {
2756        if let Some(index) = index {
2757            self.next_frame.tab_stops.begin_group(index);
2758            let result = f(self);
2759            self.next_frame.tab_stops.end_group();
2760            result
2761        } else {
2762            f(self)
2763        }
2764    }
2765
2766    /// Defers the drawing of the given element, scheduling it to be painted on top of the currently-drawn tree
2767    /// at a later time. The `priority` parameter determines the drawing order relative to other deferred elements,
2768    /// with higher values being drawn on top.
2769    ///
2770    /// This method should only be called as part of the prepaint phase of element drawing.
2771    pub fn defer_draw(
2772        &mut self,
2773        element: AnyElement,
2774        absolute_offset: Point<Pixels>,
2775        priority: usize,
2776    ) {
2777        self.invalidator.debug_assert_prepaint();
2778        let parent_node = self.next_frame.dispatch_tree.active_node_id().unwrap();
2779        self.next_frame.deferred_draws.push(DeferredDraw {
2780            current_view: self.current_view(),
2781            parent_node,
2782            element_id_stack: self.element_id_stack.clone(),
2783            text_style_stack: self.text_style_stack.clone(),
2784            priority,
2785            element: Some(element),
2786            absolute_offset,
2787            prepaint_range: PrepaintStateIndex::default()..PrepaintStateIndex::default(),
2788            paint_range: PaintIndex::default()..PaintIndex::default(),
2789        });
2790    }
2791
2792    /// Creates a new painting layer for the specified bounds. A "layer" is a batch
2793    /// of geometry that are non-overlapping and have the same draw order. This is typically used
2794    /// for performance reasons.
2795    ///
2796    /// This method should only be called as part of the paint phase of element drawing.
2797    pub fn paint_layer<R>(&mut self, bounds: Bounds<Pixels>, f: impl FnOnce(&mut Self) -> R) -> R {
2798        self.invalidator.debug_assert_paint();
2799
2800        let scale_factor = self.scale_factor();
2801        let content_mask = self.content_mask();
2802        let clipped_bounds = bounds.intersect(&content_mask.bounds);
2803        if !clipped_bounds.is_empty() {
2804            self.next_frame
2805                .scene
2806                .push_layer(clipped_bounds.scale(scale_factor));
2807        }
2808
2809        let result = f(self);
2810
2811        if !clipped_bounds.is_empty() {
2812            self.next_frame.scene.pop_layer();
2813        }
2814
2815        result
2816    }
2817
2818    /// Paint one or more drop shadows into the scene for the next frame at the current z-index.
2819    ///
2820    /// This method should only be called as part of the paint phase of element drawing.
2821    pub fn paint_shadows(
2822        &mut self,
2823        bounds: Bounds<Pixels>,
2824        corner_radii: Corners<Pixels>,
2825        shadows: &[BoxShadow],
2826    ) {
2827        self.invalidator.debug_assert_paint();
2828
2829        let scale_factor = self.scale_factor();
2830        let content_mask = self.content_mask();
2831        let opacity = self.element_opacity();
2832        for shadow in shadows {
2833            let shadow_bounds = (bounds + shadow.offset).dilate(shadow.spread_radius);
2834            self.next_frame.scene.insert_primitive(Shadow {
2835                order: 0,
2836                blur_radius: shadow.blur_radius.scale(scale_factor),
2837                bounds: shadow_bounds.scale(scale_factor),
2838                content_mask: content_mask.scale(scale_factor),
2839                corner_radii: corner_radii.scale(scale_factor),
2840                color: shadow.color.opacity(opacity),
2841            });
2842        }
2843    }
2844
2845    /// Paint one or more quads into the scene for the next frame at the current stacking context.
2846    /// Quads are colored rectangular regions with an optional background, border, and corner radius.
2847    /// see [`fill`], [`outline`], and [`quad`] to construct this type.
2848    ///
2849    /// This method should only be called as part of the paint phase of element drawing.
2850    ///
2851    /// Note that the `quad.corner_radii` are allowed to exceed the bounds, creating sharp corners
2852    /// where the circular arcs meet. This will not display well when combined with dashed borders.
2853    /// Use `Corners::clamp_radii_for_quad_size` if the radii should fit within the bounds.
2854    pub fn paint_quad(&mut self, quad: PaintQuad) {
2855        self.invalidator.debug_assert_paint();
2856
2857        let scale_factor = self.scale_factor();
2858        let content_mask = self.content_mask();
2859        let opacity = self.element_opacity();
2860        self.next_frame.scene.insert_primitive(Quad {
2861            order: 0,
2862            bounds: quad.bounds.scale(scale_factor),
2863            content_mask: content_mask.scale(scale_factor),
2864            background: quad.background.opacity(opacity),
2865            border_color: quad.border_color.opacity(opacity),
2866            corner_radii: quad.corner_radii.scale(scale_factor),
2867            border_widths: quad.border_widths.scale(scale_factor),
2868            border_style: quad.border_style,
2869        });
2870    }
2871
2872    /// Paint the given `Path` into the scene for the next frame at the current z-index.
2873    ///
2874    /// This method should only be called as part of the paint phase of element drawing.
2875    pub fn paint_path(&mut self, mut path: Path<Pixels>, color: impl Into<Background>) {
2876        self.invalidator.debug_assert_paint();
2877
2878        let scale_factor = self.scale_factor();
2879        let content_mask = self.content_mask();
2880        let opacity = self.element_opacity();
2881        path.content_mask = content_mask;
2882        let color: Background = color.into();
2883        path.color = color.opacity(opacity);
2884        self.next_frame
2885            .scene
2886            .insert_primitive(path.scale(scale_factor));
2887    }
2888
2889    /// Paint an underline into the scene for the next frame at the current z-index.
2890    ///
2891    /// This method should only be called as part of the paint phase of element drawing.
2892    pub fn paint_underline(
2893        &mut self,
2894        origin: Point<Pixels>,
2895        width: Pixels,
2896        style: &UnderlineStyle,
2897    ) {
2898        self.invalidator.debug_assert_paint();
2899
2900        let scale_factor = self.scale_factor();
2901        let height = if style.wavy {
2902            style.thickness * 3.
2903        } else {
2904            style.thickness
2905        };
2906        let bounds = Bounds {
2907            origin,
2908            size: size(width, height),
2909        };
2910        let content_mask = self.content_mask();
2911        let element_opacity = self.element_opacity();
2912
2913        self.next_frame.scene.insert_primitive(Underline {
2914            order: 0,
2915            pad: 0,
2916            bounds: bounds.scale(scale_factor),
2917            content_mask: content_mask.scale(scale_factor),
2918            color: style.color.unwrap_or_default().opacity(element_opacity),
2919            thickness: style.thickness.scale(scale_factor),
2920            wavy: if style.wavy { 1 } else { 0 },
2921        });
2922    }
2923
2924    /// Paint a strikethrough into the scene for the next frame at the current z-index.
2925    ///
2926    /// This method should only be called as part of the paint phase of element drawing.
2927    pub fn paint_strikethrough(
2928        &mut self,
2929        origin: Point<Pixels>,
2930        width: Pixels,
2931        style: &StrikethroughStyle,
2932    ) {
2933        self.invalidator.debug_assert_paint();
2934
2935        let scale_factor = self.scale_factor();
2936        let height = style.thickness;
2937        let bounds = Bounds {
2938            origin,
2939            size: size(width, height),
2940        };
2941        let content_mask = self.content_mask();
2942        let opacity = self.element_opacity();
2943
2944        self.next_frame.scene.insert_primitive(Underline {
2945            order: 0,
2946            pad: 0,
2947            bounds: bounds.scale(scale_factor),
2948            content_mask: content_mask.scale(scale_factor),
2949            thickness: style.thickness.scale(scale_factor),
2950            color: style.color.unwrap_or_default().opacity(opacity),
2951            wavy: 0,
2952        });
2953    }
2954
2955    /// Paints a monochrome (non-emoji) glyph into the scene for the next frame at the current z-index.
2956    ///
2957    /// The y component of the origin is the baseline of the glyph.
2958    /// You should generally prefer to use the [`ShapedLine::paint`](crate::ShapedLine::paint) or
2959    /// [`WrappedLine::paint`](crate::WrappedLine::paint) methods in the [`TextSystem`](crate::TextSystem).
2960    /// This method is only useful if you need to paint a single glyph that has already been shaped.
2961    ///
2962    /// This method should only be called as part of the paint phase of element drawing.
2963    pub fn paint_glyph(
2964        &mut self,
2965        origin: Point<Pixels>,
2966        font_id: FontId,
2967        glyph_id: GlyphId,
2968        font_size: Pixels,
2969        color: Hsla,
2970    ) -> Result<()> {
2971        self.invalidator.debug_assert_paint();
2972
2973        let element_opacity = self.element_opacity();
2974        let scale_factor = self.scale_factor();
2975        let glyph_origin = origin.scale(scale_factor);
2976
2977        let subpixel_variant = Point {
2978            x: (glyph_origin.x.0.fract() * SUBPIXEL_VARIANTS_X as f32).floor() as u8,
2979            y: (glyph_origin.y.0.fract() * SUBPIXEL_VARIANTS_Y as f32).floor() as u8,
2980        };
2981        let params = RenderGlyphParams {
2982            font_id,
2983            glyph_id,
2984            font_size,
2985            subpixel_variant,
2986            scale_factor,
2987            is_emoji: false,
2988        };
2989
2990        let raster_bounds = self.text_system().raster_bounds(&params)?;
2991        if !raster_bounds.is_zero() {
2992            let tile = self
2993                .sprite_atlas
2994                .get_or_insert_with(&params.clone().into(), &mut || {
2995                    let (size, bytes) = self.text_system().rasterize_glyph(&params)?;
2996                    Ok(Some((size, Cow::Owned(bytes))))
2997                })?
2998                .expect("Callback above only errors or returns Some");
2999            let bounds = Bounds {
3000                origin: glyph_origin.map(|px| px.floor()) + raster_bounds.origin.map(Into::into),
3001                size: tile.bounds.size.map(Into::into),
3002            };
3003            let content_mask = self.content_mask().scale(scale_factor);
3004            self.next_frame.scene.insert_primitive(MonochromeSprite {
3005                order: 0,
3006                pad: 0,
3007                bounds,
3008                content_mask,
3009                color: color.opacity(element_opacity),
3010                tile,
3011                transformation: TransformationMatrix::unit(),
3012            });
3013        }
3014        Ok(())
3015    }
3016
3017    /// Paints an emoji glyph into the scene for the next frame at the current z-index.
3018    ///
3019    /// The y component of the origin is the baseline of the glyph.
3020    /// You should generally prefer to use the [`ShapedLine::paint`](crate::ShapedLine::paint) or
3021    /// [`WrappedLine::paint`](crate::WrappedLine::paint) methods in the [`TextSystem`](crate::TextSystem).
3022    /// This method is only useful if you need to paint a single emoji that has already been shaped.
3023    ///
3024    /// This method should only be called as part of the paint phase of element drawing.
3025    pub fn paint_emoji(
3026        &mut self,
3027        origin: Point<Pixels>,
3028        font_id: FontId,
3029        glyph_id: GlyphId,
3030        font_size: Pixels,
3031    ) -> Result<()> {
3032        self.invalidator.debug_assert_paint();
3033
3034        let scale_factor = self.scale_factor();
3035        let glyph_origin = origin.scale(scale_factor);
3036        let params = RenderGlyphParams {
3037            font_id,
3038            glyph_id,
3039            font_size,
3040            // We don't render emojis with subpixel variants.
3041            subpixel_variant: Default::default(),
3042            scale_factor,
3043            is_emoji: true,
3044        };
3045
3046        let raster_bounds = self.text_system().raster_bounds(&params)?;
3047        if !raster_bounds.is_zero() {
3048            let tile = self
3049                .sprite_atlas
3050                .get_or_insert_with(&params.clone().into(), &mut || {
3051                    let (size, bytes) = self.text_system().rasterize_glyph(&params)?;
3052                    Ok(Some((size, Cow::Owned(bytes))))
3053                })?
3054                .expect("Callback above only errors or returns Some");
3055
3056            let bounds = Bounds {
3057                origin: glyph_origin.map(|px| px.floor()) + raster_bounds.origin.map(Into::into),
3058                size: tile.bounds.size.map(Into::into),
3059            };
3060            let content_mask = self.content_mask().scale(scale_factor);
3061            let opacity = self.element_opacity();
3062
3063            self.next_frame.scene.insert_primitive(PolychromeSprite {
3064                order: 0,
3065                pad: 0,
3066                grayscale: false,
3067                bounds,
3068                corner_radii: Default::default(),
3069                content_mask,
3070                tile,
3071                opacity,
3072            });
3073        }
3074        Ok(())
3075    }
3076
3077    /// Paint a monochrome SVG into the scene for the next frame at the current stacking context.
3078    ///
3079    /// This method should only be called as part of the paint phase of element drawing.
3080    pub fn paint_svg(
3081        &mut self,
3082        bounds: Bounds<Pixels>,
3083        path: SharedString,
3084        transformation: TransformationMatrix,
3085        color: Hsla,
3086        cx: &App,
3087    ) -> Result<()> {
3088        self.invalidator.debug_assert_paint();
3089
3090        let element_opacity = self.element_opacity();
3091        let scale_factor = self.scale_factor();
3092
3093        let bounds = bounds.scale(scale_factor);
3094        let params = RenderSvgParams {
3095            path,
3096            size: bounds.size.map(|pixels| {
3097                DevicePixels::from((pixels.0 * SMOOTH_SVG_SCALE_FACTOR).ceil() as i32)
3098            }),
3099        };
3100
3101        let Some(tile) =
3102            self.sprite_atlas
3103                .get_or_insert_with(&params.clone().into(), &mut || {
3104                    let Some((size, bytes)) = cx.svg_renderer.render(&params)? else {
3105                        return Ok(None);
3106                    };
3107                    Ok(Some((size, Cow::Owned(bytes))))
3108                })?
3109        else {
3110            return Ok(());
3111        };
3112        let content_mask = self.content_mask().scale(scale_factor);
3113        let svg_bounds = Bounds {
3114            origin: bounds.center()
3115                - Point::new(
3116                    ScaledPixels(tile.bounds.size.width.0 as f32 / SMOOTH_SVG_SCALE_FACTOR / 2.),
3117                    ScaledPixels(tile.bounds.size.height.0 as f32 / SMOOTH_SVG_SCALE_FACTOR / 2.),
3118                ),
3119            size: tile
3120                .bounds
3121                .size
3122                .map(|value| ScaledPixels(value.0 as f32 / SMOOTH_SVG_SCALE_FACTOR)),
3123        };
3124
3125        self.next_frame.scene.insert_primitive(MonochromeSprite {
3126            order: 0,
3127            pad: 0,
3128            bounds: svg_bounds
3129                .map_origin(|origin| origin.round())
3130                .map_size(|size| size.ceil()),
3131            content_mask,
3132            color: color.opacity(element_opacity),
3133            tile,
3134            transformation,
3135        });
3136
3137        Ok(())
3138    }
3139
3140    /// Paint an image into the scene for the next frame at the current z-index.
3141    /// This method will panic if the frame_index is not valid
3142    ///
3143    /// This method should only be called as part of the paint phase of element drawing.
3144    pub fn paint_image(
3145        &mut self,
3146        bounds: Bounds<Pixels>,
3147        corner_radii: Corners<Pixels>,
3148        data: Arc<RenderImage>,
3149        frame_index: usize,
3150        grayscale: bool,
3151    ) -> Result<()> {
3152        self.invalidator.debug_assert_paint();
3153
3154        let scale_factor = self.scale_factor();
3155        let bounds = bounds.scale(scale_factor);
3156        let params = RenderImageParams {
3157            image_id: data.id,
3158            frame_index,
3159        };
3160
3161        let tile = self
3162            .sprite_atlas
3163            .get_or_insert_with(&params.into(), &mut || {
3164                Ok(Some((
3165                    data.size(frame_index),
3166                    Cow::Borrowed(
3167                        data.as_bytes(frame_index)
3168                            .expect("It's the caller's job to pass a valid frame index"),
3169                    ),
3170                )))
3171            })?
3172            .expect("Callback above only returns Some");
3173        let content_mask = self.content_mask().scale(scale_factor);
3174        let corner_radii = corner_radii.scale(scale_factor);
3175        let opacity = self.element_opacity();
3176
3177        self.next_frame.scene.insert_primitive(PolychromeSprite {
3178            order: 0,
3179            pad: 0,
3180            grayscale,
3181            bounds: bounds
3182                .map_origin(|origin| origin.floor())
3183                .map_size(|size| size.ceil()),
3184            content_mask,
3185            corner_radii,
3186            tile,
3187            opacity,
3188        });
3189        Ok(())
3190    }
3191
3192    /// Paint a surface into the scene for the next frame at the current z-index.
3193    ///
3194    /// This method should only be called as part of the paint phase of element drawing.
3195    #[cfg(target_os = "macos")]
3196    pub fn paint_surface(&mut self, bounds: Bounds<Pixels>, image_buffer: CVPixelBuffer) {
3197        use crate::PaintSurface;
3198
3199        self.invalidator.debug_assert_paint();
3200
3201        let scale_factor = self.scale_factor();
3202        let bounds = bounds.scale(scale_factor);
3203        let content_mask = self.content_mask().scale(scale_factor);
3204        self.next_frame.scene.insert_primitive(PaintSurface {
3205            order: 0,
3206            bounds,
3207            content_mask,
3208            image_buffer,
3209        });
3210    }
3211
3212    /// Removes an image from the sprite atlas.
3213    pub fn drop_image(&mut self, data: Arc<RenderImage>) -> Result<()> {
3214        for frame_index in 0..data.frame_count() {
3215            let params = RenderImageParams {
3216                image_id: data.id,
3217                frame_index,
3218            };
3219
3220            self.sprite_atlas.remove(&params.clone().into());
3221        }
3222
3223        Ok(())
3224    }
3225
3226    /// Add a node to the layout tree for the current frame. Takes the `Style` of the element for which
3227    /// layout is being requested, along with the layout ids of any children. This method is called during
3228    /// calls to the [`Element::request_layout`] trait method and enables any element to participate in layout.
3229    ///
3230    /// This method should only be called as part of the request_layout or prepaint phase of element drawing.
3231    #[must_use]
3232    pub fn request_layout(
3233        &mut self,
3234        style: Style,
3235        children: impl IntoIterator<Item = LayoutId>,
3236        cx: &mut App,
3237    ) -> LayoutId {
3238        self.invalidator.debug_assert_prepaint();
3239
3240        cx.layout_id_buffer.clear();
3241        cx.layout_id_buffer.extend(children);
3242        let rem_size = self.rem_size();
3243        let scale_factor = self.scale_factor();
3244
3245        self.layout_engine.as_mut().unwrap().request_layout(
3246            style,
3247            rem_size,
3248            scale_factor,
3249            &cx.layout_id_buffer,
3250        )
3251    }
3252
3253    /// Add a node to the layout tree for the current frame. Instead of taking a `Style` and children,
3254    /// this variant takes a function that is invoked during layout so you can use arbitrary logic to
3255    /// determine the element's size. One place this is used internally is when measuring text.
3256    ///
3257    /// The given closure is invoked at layout time with the known dimensions and available space and
3258    /// returns a `Size`.
3259    ///
3260    /// This method should only be called as part of the request_layout or prepaint phase of element drawing.
3261    pub fn request_measured_layout<
3262        F: FnMut(Size<Option<Pixels>>, Size<AvailableSpace>, &mut Window, &mut App) -> Size<Pixels>
3263            + 'static,
3264    >(
3265        &mut self,
3266        style: Style,
3267        measure: F,
3268    ) -> LayoutId {
3269        self.invalidator.debug_assert_prepaint();
3270
3271        let rem_size = self.rem_size();
3272        let scale_factor = self.scale_factor();
3273        self.layout_engine
3274            .as_mut()
3275            .unwrap()
3276            .request_measured_layout(style, rem_size, scale_factor, measure)
3277    }
3278
3279    /// Compute the layout for the given id within the given available space.
3280    /// This method is called for its side effect, typically by the framework prior to painting.
3281    /// After calling it, you can request the bounds of the given layout node id or any descendant.
3282    ///
3283    /// This method should only be called as part of the prepaint phase of element drawing.
3284    pub fn compute_layout(
3285        &mut self,
3286        layout_id: LayoutId,
3287        available_space: Size<AvailableSpace>,
3288        cx: &mut App,
3289    ) {
3290        self.invalidator.debug_assert_prepaint();
3291
3292        let mut layout_engine = self.layout_engine.take().unwrap();
3293        layout_engine.compute_layout(layout_id, available_space, self, cx);
3294        self.layout_engine = Some(layout_engine);
3295    }
3296
3297    /// Obtain the bounds computed for the given LayoutId relative to the window. This method will usually be invoked by
3298    /// GPUI itself automatically in order to pass your element its `Bounds` automatically.
3299    ///
3300    /// This method should only be called as part of element drawing.
3301    pub fn layout_bounds(&mut self, layout_id: LayoutId) -> Bounds<Pixels> {
3302        self.invalidator.debug_assert_prepaint();
3303
3304        let scale_factor = self.scale_factor();
3305        let mut bounds = self
3306            .layout_engine
3307            .as_mut()
3308            .unwrap()
3309            .layout_bounds(layout_id, scale_factor)
3310            .map(Into::into);
3311        bounds.origin += self.element_offset();
3312        bounds
3313    }
3314
3315    /// This method should be called during `prepaint`. You can use
3316    /// the returned [Hitbox] during `paint` or in an event handler
3317    /// to determine whether the inserted hitbox was the topmost.
3318    ///
3319    /// This method should only be called as part of the prepaint phase of element drawing.
3320    pub fn insert_hitbox(&mut self, bounds: Bounds<Pixels>, behavior: HitboxBehavior) -> Hitbox {
3321        self.invalidator.debug_assert_prepaint();
3322
3323        let content_mask = self.content_mask();
3324        let mut id = self.next_hitbox_id;
3325        self.next_hitbox_id = self.next_hitbox_id.next();
3326        let hitbox = Hitbox {
3327            id,
3328            bounds,
3329            content_mask,
3330            behavior,
3331        };
3332        self.next_frame.hitboxes.push(hitbox.clone());
3333        hitbox
3334    }
3335
3336    /// Set a hitbox which will act as a control area of the platform window.
3337    ///
3338    /// This method should only be called as part of the paint phase of element drawing.
3339    pub fn insert_window_control_hitbox(&mut self, area: WindowControlArea, hitbox: Hitbox) {
3340        self.invalidator.debug_assert_paint();
3341        self.next_frame.window_control_hitboxes.push((area, hitbox));
3342    }
3343
3344    /// Sets the key context for the current element. This context will be used to translate
3345    /// keybindings into actions.
3346    ///
3347    /// This method should only be called as part of the paint phase of element drawing.
3348    pub fn set_key_context(&mut self, context: KeyContext) {
3349        self.invalidator.debug_assert_paint();
3350        self.next_frame.dispatch_tree.set_key_context(context);
3351    }
3352
3353    /// Sets the focus handle for the current element. This handle will be used to manage focus state
3354    /// and keyboard event dispatch for the element.
3355    ///
3356    /// This method should only be called as part of the prepaint phase of element drawing.
3357    pub fn set_focus_handle(&mut self, focus_handle: &FocusHandle, _: &App) {
3358        self.invalidator.debug_assert_prepaint();
3359        if focus_handle.is_focused(self) {
3360            self.next_frame.focus = Some(focus_handle.id);
3361        }
3362        self.next_frame.dispatch_tree.set_focus_id(focus_handle.id);
3363    }
3364
3365    /// Sets the view id for the current element, which will be used to manage view caching.
3366    ///
3367    /// This method should only be called as part of element prepaint. We plan on removing this
3368    /// method eventually when we solve some issues that require us to construct editor elements
3369    /// directly instead of always using editors via views.
3370    pub fn set_view_id(&mut self, view_id: EntityId) {
3371        self.invalidator.debug_assert_prepaint();
3372        self.next_frame.dispatch_tree.set_view_id(view_id);
3373    }
3374
3375    /// Get the entity ID for the currently rendering view
3376    pub fn current_view(&self) -> EntityId {
3377        self.invalidator.debug_assert_paint_or_prepaint();
3378        self.rendered_entity_stack.last().copied().unwrap()
3379    }
3380
3381    pub(crate) fn with_rendered_view<R>(
3382        &mut self,
3383        id: EntityId,
3384        f: impl FnOnce(&mut Self) -> R,
3385    ) -> R {
3386        self.rendered_entity_stack.push(id);
3387        let result = f(self);
3388        self.rendered_entity_stack.pop();
3389        result
3390    }
3391
3392    /// Executes the provided function with the specified image cache.
3393    pub fn with_image_cache<F, R>(&mut self, image_cache: Option<AnyImageCache>, f: F) -> R
3394    where
3395        F: FnOnce(&mut Self) -> R,
3396    {
3397        if let Some(image_cache) = image_cache {
3398            self.image_cache_stack.push(image_cache);
3399            let result = f(self);
3400            self.image_cache_stack.pop();
3401            result
3402        } else {
3403            f(self)
3404        }
3405    }
3406
3407    /// Sets an input handler, such as [`ElementInputHandler`][element_input_handler], which interfaces with the
3408    /// platform to receive textual input with proper integration with concerns such
3409    /// as IME interactions. This handler will be active for the upcoming frame until the following frame is
3410    /// rendered.
3411    ///
3412    /// This method should only be called as part of the paint phase of element drawing.
3413    ///
3414    /// [element_input_handler]: crate::ElementInputHandler
3415    pub fn handle_input(
3416        &mut self,
3417        focus_handle: &FocusHandle,
3418        input_handler: impl InputHandler,
3419        cx: &App,
3420    ) {
3421        self.invalidator.debug_assert_paint();
3422
3423        if focus_handle.is_focused(self) {
3424            let cx = self.to_async(cx);
3425            self.next_frame
3426                .input_handlers
3427                .push(Some(PlatformInputHandler::new(cx, Box::new(input_handler))));
3428        }
3429    }
3430
3431    /// Register a mouse event listener on the window for the next frame. The type of event
3432    /// is determined by the first parameter of the given listener. When the next frame is rendered
3433    /// the listener will be cleared.
3434    ///
3435    /// This method should only be called as part of the paint phase of element drawing.
3436    pub fn on_mouse_event<Event: MouseEvent>(
3437        &mut self,
3438        mut handler: impl FnMut(&Event, DispatchPhase, &mut Window, &mut App) + 'static,
3439    ) {
3440        self.invalidator.debug_assert_paint();
3441
3442        self.next_frame.mouse_listeners.push(Some(Box::new(
3443            move |event: &dyn Any, phase: DispatchPhase, window: &mut Window, cx: &mut App| {
3444                if let Some(event) = event.downcast_ref() {
3445                    handler(event, phase, window, cx)
3446                }
3447            },
3448        )));
3449    }
3450
3451    /// Register a key event listener on the window for the next frame. The type of event
3452    /// is determined by the first parameter of the given listener. When the next frame is rendered
3453    /// the listener will be cleared.
3454    ///
3455    /// This is a fairly low-level method, so prefer using event handlers on elements unless you have
3456    /// a specific need to register a global listener.
3457    ///
3458    /// This method should only be called as part of the paint phase of element drawing.
3459    pub fn on_key_event<Event: KeyEvent>(
3460        &mut self,
3461        listener: impl Fn(&Event, DispatchPhase, &mut Window, &mut App) + 'static,
3462    ) {
3463        self.invalidator.debug_assert_paint();
3464
3465        self.next_frame.dispatch_tree.on_key_event(Rc::new(
3466            move |event: &dyn Any, phase, window: &mut Window, cx: &mut App| {
3467                if let Some(event) = event.downcast_ref::<Event>() {
3468                    listener(event, phase, window, cx)
3469                }
3470            },
3471        ));
3472    }
3473
3474    /// Register a modifiers changed event listener on the window for the next frame.
3475    ///
3476    /// This is a fairly low-level method, so prefer using event handlers on elements unless you have
3477    /// a specific need to register a global listener.
3478    ///
3479    /// This method should only be called as part of the paint phase of element drawing.
3480    pub fn on_modifiers_changed(
3481        &mut self,
3482        listener: impl Fn(&ModifiersChangedEvent, &mut Window, &mut App) + 'static,
3483    ) {
3484        self.invalidator.debug_assert_paint();
3485
3486        self.next_frame.dispatch_tree.on_modifiers_changed(Rc::new(
3487            move |event: &ModifiersChangedEvent, window: &mut Window, cx: &mut App| {
3488                listener(event, window, cx)
3489            },
3490        ));
3491    }
3492
3493    /// Register a listener to be called when the given focus handle or one of its descendants receives focus.
3494    /// This does not fire if the given focus handle - or one of its descendants - was previously focused.
3495    /// Returns a subscription and persists until the subscription is dropped.
3496    pub fn on_focus_in(
3497        &mut self,
3498        handle: &FocusHandle,
3499        cx: &mut App,
3500        mut listener: impl FnMut(&mut Window, &mut App) + 'static,
3501    ) -> Subscription {
3502        let focus_id = handle.id;
3503        let (subscription, activate) =
3504            self.new_focus_listener(Box::new(move |event, window, cx| {
3505                if event.is_focus_in(focus_id) {
3506                    listener(window, cx);
3507                }
3508                true
3509            }));
3510        cx.defer(move |_| activate());
3511        subscription
3512    }
3513
3514    /// Register a listener to be called when the given focus handle or one of its descendants loses focus.
3515    /// Returns a subscription and persists until the subscription is dropped.
3516    pub fn on_focus_out(
3517        &mut self,
3518        handle: &FocusHandle,
3519        cx: &mut App,
3520        mut listener: impl FnMut(FocusOutEvent, &mut Window, &mut App) + 'static,
3521    ) -> Subscription {
3522        let focus_id = handle.id;
3523        let (subscription, activate) =
3524            self.new_focus_listener(Box::new(move |event, window, cx| {
3525                if let Some(blurred_id) = event.previous_focus_path.last().copied()
3526                    && event.is_focus_out(focus_id)
3527                {
3528                    let event = FocusOutEvent {
3529                        blurred: WeakFocusHandle {
3530                            id: blurred_id,
3531                            handles: Arc::downgrade(&cx.focus_handles),
3532                        },
3533                    };
3534                    listener(event, window, cx)
3535                }
3536                true
3537            }));
3538        cx.defer(move |_| activate());
3539        subscription
3540    }
3541
3542    fn reset_cursor_style(&self, cx: &mut App) {
3543        // Set the cursor only if we're the active window.
3544        if self.is_window_hovered() {
3545            let style = self
3546                .rendered_frame
3547                .cursor_style(self)
3548                .unwrap_or(CursorStyle::Arrow);
3549            cx.platform.set_cursor_style(style);
3550        }
3551    }
3552
3553    /// Dispatch a given keystroke as though the user had typed it.
3554    /// You can create a keystroke with Keystroke::parse("").
3555    pub fn dispatch_keystroke(&mut self, keystroke: Keystroke, cx: &mut App) -> bool {
3556        let keystroke = keystroke.with_simulated_ime();
3557        let result = self.dispatch_event(
3558            PlatformInput::KeyDown(KeyDownEvent {
3559                keystroke: keystroke.clone(),
3560                is_held: false,
3561            }),
3562            cx,
3563        );
3564        if !result.propagate {
3565            return true;
3566        }
3567
3568        if let Some(input) = keystroke.key_char
3569            && let Some(mut input_handler) = self.platform_window.take_input_handler()
3570        {
3571            input_handler.dispatch_input(&input, self, cx);
3572            self.platform_window.set_input_handler(input_handler);
3573            return true;
3574        }
3575
3576        false
3577    }
3578
3579    /// Return a key binding string for an action, to display in the UI. Uses the highest precedence
3580    /// binding for the action (last binding added to the keymap).
3581    pub fn keystroke_text_for(&self, action: &dyn Action) -> String {
3582        self.highest_precedence_binding_for_action(action)
3583            .map(|binding| {
3584                binding
3585                    .keystrokes()
3586                    .iter()
3587                    .map(ToString::to_string)
3588                    .collect::<Vec<_>>()
3589                    .join(" ")
3590            })
3591            .unwrap_or_else(|| action.name().to_string())
3592    }
3593
3594    /// Dispatch a mouse or keyboard event on the window.
3595    #[profiling::function]
3596    pub fn dispatch_event(&mut self, event: PlatformInput, cx: &mut App) -> DispatchEventResult {
3597        self.last_input_timestamp.set(Instant::now());
3598
3599        // Track whether this input was keyboard-based for focus-visible styling
3600        self.last_input_was_keyboard = matches!(
3601            event,
3602            PlatformInput::KeyDown(_)
3603                | PlatformInput::KeyUp(_)
3604                | PlatformInput::ModifiersChanged(_)
3605        );
3606
3607        // Handlers may set this to false by calling `stop_propagation`.
3608        cx.propagate_event = true;
3609        // Handlers may set this to true by calling `prevent_default`.
3610        self.default_prevented = false;
3611
3612        let event = match event {
3613            // Track the mouse position with our own state, since accessing the platform
3614            // API for the mouse position can only occur on the main thread.
3615            PlatformInput::MouseMove(mouse_move) => {
3616                self.mouse_position = mouse_move.position;
3617                self.modifiers = mouse_move.modifiers;
3618                PlatformInput::MouseMove(mouse_move)
3619            }
3620            PlatformInput::MouseDown(mouse_down) => {
3621                self.mouse_position = mouse_down.position;
3622                self.modifiers = mouse_down.modifiers;
3623                PlatformInput::MouseDown(mouse_down)
3624            }
3625            PlatformInput::MouseUp(mouse_up) => {
3626                self.mouse_position = mouse_up.position;
3627                self.modifiers = mouse_up.modifiers;
3628                PlatformInput::MouseUp(mouse_up)
3629            }
3630            PlatformInput::MouseExited(mouse_exited) => {
3631                self.modifiers = mouse_exited.modifiers;
3632                PlatformInput::MouseExited(mouse_exited)
3633            }
3634            PlatformInput::ModifiersChanged(modifiers_changed) => {
3635                self.modifiers = modifiers_changed.modifiers;
3636                self.capslock = modifiers_changed.capslock;
3637                PlatformInput::ModifiersChanged(modifiers_changed)
3638            }
3639            PlatformInput::ScrollWheel(scroll_wheel) => {
3640                self.mouse_position = scroll_wheel.position;
3641                self.modifiers = scroll_wheel.modifiers;
3642                PlatformInput::ScrollWheel(scroll_wheel)
3643            }
3644            // Translate dragging and dropping of external files from the operating system
3645            // to internal drag and drop events.
3646            PlatformInput::FileDrop(file_drop) => match file_drop {
3647                FileDropEvent::Entered { position, paths } => {
3648                    self.mouse_position = position;
3649                    if cx.active_drag.is_none() {
3650                        cx.active_drag = Some(AnyDrag {
3651                            value: Arc::new(paths.clone()),
3652                            view: cx.new(|_| paths).into(),
3653                            cursor_offset: position,
3654                            cursor_style: None,
3655                        });
3656                    }
3657                    PlatformInput::MouseMove(MouseMoveEvent {
3658                        position,
3659                        pressed_button: Some(MouseButton::Left),
3660                        modifiers: Modifiers::default(),
3661                    })
3662                }
3663                FileDropEvent::Pending { position } => {
3664                    self.mouse_position = position;
3665                    PlatformInput::MouseMove(MouseMoveEvent {
3666                        position,
3667                        pressed_button: Some(MouseButton::Left),
3668                        modifiers: Modifiers::default(),
3669                    })
3670                }
3671                FileDropEvent::Submit { position } => {
3672                    cx.activate(true);
3673                    self.mouse_position = position;
3674                    PlatformInput::MouseUp(MouseUpEvent {
3675                        button: MouseButton::Left,
3676                        position,
3677                        modifiers: Modifiers::default(),
3678                        click_count: 1,
3679                    })
3680                }
3681                FileDropEvent::Exited => {
3682                    cx.active_drag.take();
3683                    PlatformInput::FileDrop(FileDropEvent::Exited)
3684                }
3685            },
3686            PlatformInput::KeyDown(_) | PlatformInput::KeyUp(_) => event,
3687        };
3688
3689        if let Some(any_mouse_event) = event.mouse_event() {
3690            self.dispatch_mouse_event(any_mouse_event, cx);
3691        } else if let Some(any_key_event) = event.keyboard_event() {
3692            self.dispatch_key_event(any_key_event, cx);
3693        }
3694
3695        DispatchEventResult {
3696            propagate: cx.propagate_event,
3697            default_prevented: self.default_prevented,
3698        }
3699    }
3700
3701    fn dispatch_mouse_event(&mut self, event: &dyn Any, cx: &mut App) {
3702        let hit_test = self.rendered_frame.hit_test(self.mouse_position());
3703        if hit_test != self.mouse_hit_test {
3704            self.mouse_hit_test = hit_test;
3705            self.reset_cursor_style(cx);
3706        }
3707
3708        #[cfg(any(feature = "inspector", debug_assertions))]
3709        if self.is_inspector_picking(cx) {
3710            self.handle_inspector_mouse_event(event, cx);
3711            // When inspector is picking, all other mouse handling is skipped.
3712            return;
3713        }
3714
3715        let mut mouse_listeners = mem::take(&mut self.rendered_frame.mouse_listeners);
3716
3717        // Capture phase, events bubble from back to front. Handlers for this phase are used for
3718        // special purposes, such as detecting events outside of a given Bounds.
3719        for listener in &mut mouse_listeners {
3720            let listener = listener.as_mut().unwrap();
3721            listener(event, DispatchPhase::Capture, self, cx);
3722            if !cx.propagate_event {
3723                break;
3724            }
3725        }
3726
3727        // Bubble phase, where most normal handlers do their work.
3728        if cx.propagate_event {
3729            for listener in mouse_listeners.iter_mut().rev() {
3730                let listener = listener.as_mut().unwrap();
3731                listener(event, DispatchPhase::Bubble, self, cx);
3732                if !cx.propagate_event {
3733                    break;
3734                }
3735            }
3736        }
3737
3738        self.rendered_frame.mouse_listeners = mouse_listeners;
3739
3740        if cx.has_active_drag() {
3741            if event.is::<MouseMoveEvent>() {
3742                // If this was a mouse move event, redraw the window so that the
3743                // active drag can follow the mouse cursor.
3744                self.refresh();
3745            } else if event.is::<MouseUpEvent>() {
3746                // If this was a mouse up event, cancel the active drag and redraw
3747                // the window.
3748                cx.active_drag = None;
3749                self.refresh();
3750            }
3751        }
3752    }
3753
3754    fn dispatch_key_event(&mut self, event: &dyn Any, cx: &mut App) {
3755        if self.invalidator.is_dirty() {
3756            self.draw(cx).clear();
3757        }
3758
3759        let node_id = self.focus_node_id_in_rendered_frame(self.focus);
3760        let dispatch_path = self.rendered_frame.dispatch_tree.dispatch_path(node_id);
3761
3762        let mut keystroke: Option<Keystroke> = None;
3763
3764        if let Some(event) = event.downcast_ref::<ModifiersChangedEvent>() {
3765            if event.modifiers.number_of_modifiers() == 0
3766                && self.pending_modifier.modifiers.number_of_modifiers() == 1
3767                && !self.pending_modifier.saw_keystroke
3768            {
3769                let key = match self.pending_modifier.modifiers {
3770                    modifiers if modifiers.shift => Some("shift"),
3771                    modifiers if modifiers.control => Some("control"),
3772                    modifiers if modifiers.alt => Some("alt"),
3773                    modifiers if modifiers.platform => Some("platform"),
3774                    modifiers if modifiers.function => Some("function"),
3775                    _ => None,
3776                };
3777                if let Some(key) = key {
3778                    keystroke = Some(Keystroke {
3779                        key: key.to_string(),
3780                        key_char: None,
3781                        modifiers: Modifiers::default(),
3782                    });
3783                }
3784            }
3785
3786            if self.pending_modifier.modifiers.number_of_modifiers() == 0
3787                && event.modifiers.number_of_modifiers() == 1
3788            {
3789                self.pending_modifier.saw_keystroke = false
3790            }
3791            self.pending_modifier.modifiers = event.modifiers
3792        } else if let Some(key_down_event) = event.downcast_ref::<KeyDownEvent>() {
3793            self.pending_modifier.saw_keystroke = true;
3794            keystroke = Some(key_down_event.keystroke.clone());
3795        }
3796
3797        let Some(keystroke) = keystroke else {
3798            self.finish_dispatch_key_event(event, dispatch_path, self.context_stack(), cx);
3799            return;
3800        };
3801
3802        cx.propagate_event = true;
3803        self.dispatch_keystroke_interceptors(event, self.context_stack(), cx);
3804        if !cx.propagate_event {
3805            self.finish_dispatch_key_event(event, dispatch_path, self.context_stack(), cx);
3806            return;
3807        }
3808
3809        let mut currently_pending = self.pending_input.take().unwrap_or_default();
3810        if currently_pending.focus.is_some() && currently_pending.focus != self.focus {
3811            currently_pending = PendingInput::default();
3812        }
3813
3814        let match_result = self.rendered_frame.dispatch_tree.dispatch_key(
3815            currently_pending.keystrokes,
3816            keystroke,
3817            &dispatch_path,
3818        );
3819
3820        if !match_result.to_replay.is_empty() {
3821            self.replay_pending_input(match_result.to_replay, cx);
3822            cx.propagate_event = true;
3823        }
3824
3825        if !match_result.pending.is_empty() {
3826            currently_pending.keystrokes = match_result.pending;
3827            currently_pending.focus = self.focus;
3828            currently_pending.timer = Some(self.spawn(cx, async move |cx| {
3829                cx.background_executor.timer(Duration::from_secs(1)).await;
3830                cx.update(move |window, cx| {
3831                    let Some(currently_pending) = window
3832                        .pending_input
3833                        .take()
3834                        .filter(|pending| pending.focus == window.focus)
3835                    else {
3836                        return;
3837                    };
3838
3839                    let node_id = window.focus_node_id_in_rendered_frame(window.focus);
3840                    let dispatch_path = window.rendered_frame.dispatch_tree.dispatch_path(node_id);
3841
3842                    let to_replay = window
3843                        .rendered_frame
3844                        .dispatch_tree
3845                        .flush_dispatch(currently_pending.keystrokes, &dispatch_path);
3846
3847                    window.pending_input_changed(cx);
3848                    window.replay_pending_input(to_replay, cx)
3849                })
3850                .log_err();
3851            }));
3852            self.pending_input = Some(currently_pending);
3853            self.pending_input_changed(cx);
3854            cx.propagate_event = false;
3855            return;
3856        }
3857
3858        for binding in match_result.bindings {
3859            self.dispatch_action_on_node(node_id, binding.action.as_ref(), cx);
3860            if !cx.propagate_event {
3861                self.dispatch_keystroke_observers(
3862                    event,
3863                    Some(binding.action),
3864                    match_result.context_stack,
3865                    cx,
3866                );
3867                self.pending_input_changed(cx);
3868                return;
3869            }
3870        }
3871
3872        self.finish_dispatch_key_event(event, dispatch_path, match_result.context_stack, cx);
3873        self.pending_input_changed(cx);
3874    }
3875
3876    fn finish_dispatch_key_event(
3877        &mut self,
3878        event: &dyn Any,
3879        dispatch_path: SmallVec<[DispatchNodeId; 32]>,
3880        context_stack: Vec<KeyContext>,
3881        cx: &mut App,
3882    ) {
3883        self.dispatch_key_down_up_event(event, &dispatch_path, cx);
3884        if !cx.propagate_event {
3885            return;
3886        }
3887
3888        self.dispatch_modifiers_changed_event(event, &dispatch_path, cx);
3889        if !cx.propagate_event {
3890            return;
3891        }
3892
3893        self.dispatch_keystroke_observers(event, None, context_stack, cx);
3894    }
3895
3896    fn pending_input_changed(&mut self, cx: &mut App) {
3897        self.pending_input_observers
3898            .clone()
3899            .retain(&(), |callback| callback(self, cx));
3900    }
3901
3902    fn dispatch_key_down_up_event(
3903        &mut self,
3904        event: &dyn Any,
3905        dispatch_path: &SmallVec<[DispatchNodeId; 32]>,
3906        cx: &mut App,
3907    ) {
3908        // Capture phase
3909        for node_id in dispatch_path {
3910            let node = self.rendered_frame.dispatch_tree.node(*node_id);
3911
3912            for key_listener in node.key_listeners.clone() {
3913                key_listener(event, DispatchPhase::Capture, self, cx);
3914                if !cx.propagate_event {
3915                    return;
3916                }
3917            }
3918        }
3919
3920        // Bubble phase
3921        for node_id in dispatch_path.iter().rev() {
3922            // Handle low level key events
3923            let node = self.rendered_frame.dispatch_tree.node(*node_id);
3924            for key_listener in node.key_listeners.clone() {
3925                key_listener(event, DispatchPhase::Bubble, self, cx);
3926                if !cx.propagate_event {
3927                    return;
3928                }
3929            }
3930        }
3931    }
3932
3933    fn dispatch_modifiers_changed_event(
3934        &mut self,
3935        event: &dyn Any,
3936        dispatch_path: &SmallVec<[DispatchNodeId; 32]>,
3937        cx: &mut App,
3938    ) {
3939        let Some(event) = event.downcast_ref::<ModifiersChangedEvent>() else {
3940            return;
3941        };
3942        for node_id in dispatch_path.iter().rev() {
3943            let node = self.rendered_frame.dispatch_tree.node(*node_id);
3944            for listener in node.modifiers_changed_listeners.clone() {
3945                listener(event, self, cx);
3946                if !cx.propagate_event {
3947                    return;
3948                }
3949            }
3950        }
3951    }
3952
3953    /// Determine whether a potential multi-stroke key binding is in progress on this window.
3954    pub fn has_pending_keystrokes(&self) -> bool {
3955        self.pending_input.is_some()
3956    }
3957
3958    pub(crate) fn clear_pending_keystrokes(&mut self) {
3959        self.pending_input.take();
3960    }
3961
3962    /// Returns the currently pending input keystrokes that might result in a multi-stroke key binding.
3963    pub fn pending_input_keystrokes(&self) -> Option<&[Keystroke]> {
3964        self.pending_input
3965            .as_ref()
3966            .map(|pending_input| pending_input.keystrokes.as_slice())
3967    }
3968
3969    fn replay_pending_input(&mut self, replays: SmallVec<[Replay; 1]>, cx: &mut App) {
3970        let node_id = self.focus_node_id_in_rendered_frame(self.focus);
3971        let dispatch_path = self.rendered_frame.dispatch_tree.dispatch_path(node_id);
3972
3973        'replay: for replay in replays {
3974            let event = KeyDownEvent {
3975                keystroke: replay.keystroke.clone(),
3976                is_held: false,
3977            };
3978
3979            cx.propagate_event = true;
3980            for binding in replay.bindings {
3981                self.dispatch_action_on_node(node_id, binding.action.as_ref(), cx);
3982                if !cx.propagate_event {
3983                    self.dispatch_keystroke_observers(
3984                        &event,
3985                        Some(binding.action),
3986                        Vec::default(),
3987                        cx,
3988                    );
3989                    continue 'replay;
3990                }
3991            }
3992
3993            self.dispatch_key_down_up_event(&event, &dispatch_path, cx);
3994            if !cx.propagate_event {
3995                continue 'replay;
3996            }
3997            if let Some(input) = replay.keystroke.key_char.as_ref().cloned()
3998                && let Some(mut input_handler) = self.platform_window.take_input_handler()
3999            {
4000                input_handler.dispatch_input(&input, self, cx);
4001                self.platform_window.set_input_handler(input_handler)
4002            }
4003        }
4004    }
4005
4006    fn focus_node_id_in_rendered_frame(&self, focus_id: Option<FocusId>) -> DispatchNodeId {
4007        focus_id
4008            .and_then(|focus_id| {
4009                self.rendered_frame
4010                    .dispatch_tree
4011                    .focusable_node_id(focus_id)
4012            })
4013            .unwrap_or_else(|| self.rendered_frame.dispatch_tree.root_node_id())
4014    }
4015
4016    fn dispatch_action_on_node(
4017        &mut self,
4018        node_id: DispatchNodeId,
4019        action: &dyn Action,
4020        cx: &mut App,
4021    ) {
4022        let dispatch_path = self.rendered_frame.dispatch_tree.dispatch_path(node_id);
4023
4024        // Capture phase for global actions.
4025        cx.propagate_event = true;
4026        if let Some(mut global_listeners) = cx
4027            .global_action_listeners
4028            .remove(&action.as_any().type_id())
4029        {
4030            for listener in &global_listeners {
4031                listener(action.as_any(), DispatchPhase::Capture, cx);
4032                if !cx.propagate_event {
4033                    break;
4034                }
4035            }
4036
4037            global_listeners.extend(
4038                cx.global_action_listeners
4039                    .remove(&action.as_any().type_id())
4040                    .unwrap_or_default(),
4041            );
4042
4043            cx.global_action_listeners
4044                .insert(action.as_any().type_id(), global_listeners);
4045        }
4046
4047        if !cx.propagate_event {
4048            return;
4049        }
4050
4051        // Capture phase for window actions.
4052        for node_id in &dispatch_path {
4053            let node = self.rendered_frame.dispatch_tree.node(*node_id);
4054            for DispatchActionListener {
4055                action_type,
4056                listener,
4057            } in node.action_listeners.clone()
4058            {
4059                let any_action = action.as_any();
4060                if action_type == any_action.type_id() {
4061                    listener(any_action, DispatchPhase::Capture, self, cx);
4062
4063                    if !cx.propagate_event {
4064                        return;
4065                    }
4066                }
4067            }
4068        }
4069
4070        // Bubble phase for window actions.
4071        for node_id in dispatch_path.iter().rev() {
4072            let node = self.rendered_frame.dispatch_tree.node(*node_id);
4073            for DispatchActionListener {
4074                action_type,
4075                listener,
4076            } in node.action_listeners.clone()
4077            {
4078                let any_action = action.as_any();
4079                if action_type == any_action.type_id() {
4080                    cx.propagate_event = false; // Actions stop propagation by default during the bubble phase
4081                    listener(any_action, DispatchPhase::Bubble, self, cx);
4082
4083                    if !cx.propagate_event {
4084                        return;
4085                    }
4086                }
4087            }
4088        }
4089
4090        // Bubble phase for global actions.
4091        if let Some(mut global_listeners) = cx
4092            .global_action_listeners
4093            .remove(&action.as_any().type_id())
4094        {
4095            for listener in global_listeners.iter().rev() {
4096                cx.propagate_event = false; // Actions stop propagation by default during the bubble phase
4097
4098                listener(action.as_any(), DispatchPhase::Bubble, cx);
4099                if !cx.propagate_event {
4100                    break;
4101                }
4102            }
4103
4104            global_listeners.extend(
4105                cx.global_action_listeners
4106                    .remove(&action.as_any().type_id())
4107                    .unwrap_or_default(),
4108            );
4109
4110            cx.global_action_listeners
4111                .insert(action.as_any().type_id(), global_listeners);
4112        }
4113    }
4114
4115    /// Register the given handler to be invoked whenever the global of the given type
4116    /// is updated.
4117    pub fn observe_global<G: Global>(
4118        &mut self,
4119        cx: &mut App,
4120        f: impl Fn(&mut Window, &mut App) + 'static,
4121    ) -> Subscription {
4122        let window_handle = self.handle;
4123        let (subscription, activate) = cx.global_observers.insert(
4124            TypeId::of::<G>(),
4125            Box::new(move |cx| {
4126                window_handle
4127                    .update(cx, |_, window, cx| f(window, cx))
4128                    .is_ok()
4129            }),
4130        );
4131        cx.defer(move |_| activate());
4132        subscription
4133    }
4134
4135    /// Focus the current window and bring it to the foreground at the platform level.
4136    pub fn activate_window(&self) {
4137        self.platform_window.activate();
4138    }
4139
4140    /// Minimize the current window at the platform level.
4141    pub fn minimize_window(&self) {
4142        self.platform_window.minimize();
4143    }
4144
4145    /// Toggle full screen status on the current window at the platform level.
4146    pub fn toggle_fullscreen(&self) {
4147        self.platform_window.toggle_fullscreen();
4148    }
4149
4150    /// Updates the IME panel position suggestions for languages like japanese, chinese.
4151    pub fn invalidate_character_coordinates(&self) {
4152        self.on_next_frame(|window, cx| {
4153            if let Some(mut input_handler) = window.platform_window.take_input_handler() {
4154                if let Some(bounds) = input_handler.selected_bounds(window, cx) {
4155                    window.platform_window.update_ime_position(bounds);
4156                }
4157                window.platform_window.set_input_handler(input_handler);
4158            }
4159        });
4160    }
4161
4162    /// Present a platform dialog.
4163    /// The provided message will be presented, along with buttons for each answer.
4164    /// When a button is clicked, the returned Receiver will receive the index of the clicked button.
4165    pub fn prompt<T>(
4166        &mut self,
4167        level: PromptLevel,
4168        message: &str,
4169        detail: Option<&str>,
4170        answers: &[T],
4171        cx: &mut App,
4172    ) -> oneshot::Receiver<usize>
4173    where
4174        T: Clone + Into<PromptButton>,
4175    {
4176        let prompt_builder = cx.prompt_builder.take();
4177        let Some(prompt_builder) = prompt_builder else {
4178            unreachable!("Re-entrant window prompting is not supported by GPUI");
4179        };
4180
4181        let answers = answers
4182            .iter()
4183            .map(|answer| answer.clone().into())
4184            .collect::<Vec<_>>();
4185
4186        let receiver = match &prompt_builder {
4187            PromptBuilder::Default => self
4188                .platform_window
4189                .prompt(level, message, detail, &answers)
4190                .unwrap_or_else(|| {
4191                    self.build_custom_prompt(&prompt_builder, level, message, detail, &answers, cx)
4192                }),
4193            PromptBuilder::Custom(_) => {
4194                self.build_custom_prompt(&prompt_builder, level, message, detail, &answers, cx)
4195            }
4196        };
4197
4198        cx.prompt_builder = Some(prompt_builder);
4199
4200        receiver
4201    }
4202
4203    fn build_custom_prompt(
4204        &mut self,
4205        prompt_builder: &PromptBuilder,
4206        level: PromptLevel,
4207        message: &str,
4208        detail: Option<&str>,
4209        answers: &[PromptButton],
4210        cx: &mut App,
4211    ) -> oneshot::Receiver<usize> {
4212        let (sender, receiver) = oneshot::channel();
4213        let handle = PromptHandle::new(sender);
4214        let handle = (prompt_builder)(level, message, detail, answers, handle, self, cx);
4215        self.prompt = Some(handle);
4216        receiver
4217    }
4218
4219    /// Returns the current context stack.
4220    pub fn context_stack(&self) -> Vec<KeyContext> {
4221        let node_id = self.focus_node_id_in_rendered_frame(self.focus);
4222        let dispatch_tree = &self.rendered_frame.dispatch_tree;
4223        dispatch_tree
4224            .dispatch_path(node_id)
4225            .iter()
4226            .filter_map(move |&node_id| dispatch_tree.node(node_id).context.clone())
4227            .collect()
4228    }
4229
4230    /// Returns all available actions for the focused element.
4231    pub fn available_actions(&self, cx: &App) -> Vec<Box<dyn Action>> {
4232        let node_id = self.focus_node_id_in_rendered_frame(self.focus);
4233        let mut actions = self.rendered_frame.dispatch_tree.available_actions(node_id);
4234        for action_type in cx.global_action_listeners.keys() {
4235            if let Err(ix) = actions.binary_search_by_key(action_type, |a| a.as_any().type_id()) {
4236                let action = cx.actions.build_action_type(action_type).ok();
4237                if let Some(action) = action {
4238                    actions.insert(ix, action);
4239                }
4240            }
4241        }
4242        actions
4243    }
4244
4245    /// Returns key bindings that invoke an action on the currently focused element. Bindings are
4246    /// returned in the order they were added. For display, the last binding should take precedence.
4247    pub fn bindings_for_action(&self, action: &dyn Action) -> Vec<KeyBinding> {
4248        self.rendered_frame
4249            .dispatch_tree
4250            .bindings_for_action(action, &self.rendered_frame.dispatch_tree.context_stack)
4251    }
4252
4253    /// Returns the highest precedence key binding that invokes an action on the currently focused
4254    /// element. This is more efficient than getting the last result of `bindings_for_action`.
4255    pub fn highest_precedence_binding_for_action(&self, action: &dyn Action) -> Option<KeyBinding> {
4256        self.rendered_frame
4257            .dispatch_tree
4258            .highest_precedence_binding_for_action(
4259                action,
4260                &self.rendered_frame.dispatch_tree.context_stack,
4261            )
4262    }
4263
4264    /// Returns the key bindings for an action in a context.
4265    pub fn bindings_for_action_in_context(
4266        &self,
4267        action: &dyn Action,
4268        context: KeyContext,
4269    ) -> Vec<KeyBinding> {
4270        let dispatch_tree = &self.rendered_frame.dispatch_tree;
4271        dispatch_tree.bindings_for_action(action, &[context])
4272    }
4273
4274    /// Returns the highest precedence key binding for an action in a context. This is more
4275    /// efficient than getting the last result of `bindings_for_action_in_context`.
4276    pub fn highest_precedence_binding_for_action_in_context(
4277        &self,
4278        action: &dyn Action,
4279        context: KeyContext,
4280    ) -> Option<KeyBinding> {
4281        let dispatch_tree = &self.rendered_frame.dispatch_tree;
4282        dispatch_tree.highest_precedence_binding_for_action(action, &[context])
4283    }
4284
4285    /// Returns any bindings that would invoke an action on the given focus handle if it were
4286    /// focused. Bindings are returned in the order they were added. For display, the last binding
4287    /// should take precedence.
4288    pub fn bindings_for_action_in(
4289        &self,
4290        action: &dyn Action,
4291        focus_handle: &FocusHandle,
4292    ) -> Vec<KeyBinding> {
4293        let dispatch_tree = &self.rendered_frame.dispatch_tree;
4294        let Some(context_stack) = self.context_stack_for_focus_handle(focus_handle) else {
4295            return vec![];
4296        };
4297        dispatch_tree.bindings_for_action(action, &context_stack)
4298    }
4299
4300    /// Returns the highest precedence key binding that would invoke an action on the given focus
4301    /// handle if it were focused. This is more efficient than getting the last result of
4302    /// `bindings_for_action_in`.
4303    pub fn highest_precedence_binding_for_action_in(
4304        &self,
4305        action: &dyn Action,
4306        focus_handle: &FocusHandle,
4307    ) -> Option<KeyBinding> {
4308        let dispatch_tree = &self.rendered_frame.dispatch_tree;
4309        let context_stack = self.context_stack_for_focus_handle(focus_handle)?;
4310        dispatch_tree.highest_precedence_binding_for_action(action, &context_stack)
4311    }
4312
4313    fn context_stack_for_focus_handle(
4314        &self,
4315        focus_handle: &FocusHandle,
4316    ) -> Option<Vec<KeyContext>> {
4317        let dispatch_tree = &self.rendered_frame.dispatch_tree;
4318        let node_id = dispatch_tree.focusable_node_id(focus_handle.id)?;
4319        let context_stack: Vec<_> = dispatch_tree
4320            .dispatch_path(node_id)
4321            .into_iter()
4322            .filter_map(|node_id| dispatch_tree.node(node_id).context.clone())
4323            .collect();
4324        Some(context_stack)
4325    }
4326
4327    /// Returns a generic event listener that invokes the given listener with the view and context associated with the given view handle.
4328    pub fn listener_for<V: Render, E>(
4329        &self,
4330        view: &Entity<V>,
4331        f: impl Fn(&mut V, &E, &mut Window, &mut Context<V>) + 'static,
4332    ) -> impl Fn(&E, &mut Window, &mut App) + 'static {
4333        let view = view.downgrade();
4334        move |e: &E, window: &mut Window, cx: &mut App| {
4335            view.update(cx, |view, cx| f(view, e, window, cx)).ok();
4336        }
4337    }
4338
4339    /// Returns a generic handler that invokes the given handler with the view and context associated with the given view handle.
4340    pub fn handler_for<E: 'static, Callback: Fn(&mut E, &mut Window, &mut Context<E>) + 'static>(
4341        &self,
4342        entity: &Entity<E>,
4343        f: Callback,
4344    ) -> impl Fn(&mut Window, &mut App) + 'static {
4345        let entity = entity.downgrade();
4346        move |window: &mut Window, cx: &mut App| {
4347            entity.update(cx, |entity, cx| f(entity, window, cx)).ok();
4348        }
4349    }
4350
4351    /// Register a callback that can interrupt the closing of the current window based the returned boolean.
4352    /// If the callback returns false, the window won't be closed.
4353    pub fn on_window_should_close(
4354        &self,
4355        cx: &App,
4356        f: impl Fn(&mut Window, &mut App) -> bool + 'static,
4357    ) {
4358        let mut cx = self.to_async(cx);
4359        self.platform_window.on_should_close(Box::new(move || {
4360            cx.update(|window, cx| f(window, cx)).unwrap_or(true)
4361        }))
4362    }
4363
4364    /// Register an action listener on the window for the next frame. The type of action
4365    /// is determined by the first parameter of the given listener. When the next frame is rendered
4366    /// the listener will be cleared.
4367    ///
4368    /// This is a fairly low-level method, so prefer using action handlers on elements unless you have
4369    /// a specific need to register a global listener.
4370    pub fn on_action(
4371        &mut self,
4372        action_type: TypeId,
4373        listener: impl Fn(&dyn Any, DispatchPhase, &mut Window, &mut App) + 'static,
4374    ) {
4375        self.next_frame
4376            .dispatch_tree
4377            .on_action(action_type, Rc::new(listener));
4378    }
4379
4380    /// Register an action listener on the window for the next frame if the condition is true.
4381    /// The type of action is determined by the first parameter of the given listener.
4382    /// When the next frame is rendered the listener will be cleared.
4383    ///
4384    /// This is a fairly low-level method, so prefer using action handlers on elements unless you have
4385    /// a specific need to register a global listener.
4386    pub fn on_action_when(
4387        &mut self,
4388        condition: bool,
4389        action_type: TypeId,
4390        listener: impl Fn(&dyn Any, DispatchPhase, &mut Window, &mut App) + 'static,
4391    ) {
4392        if condition {
4393            self.next_frame
4394                .dispatch_tree
4395                .on_action(action_type, Rc::new(listener));
4396        }
4397    }
4398
4399    /// Read information about the GPU backing this window.
4400    /// Currently returns None on Mac and Windows.
4401    pub fn gpu_specs(&self) -> Option<GpuSpecs> {
4402        self.platform_window.gpu_specs()
4403    }
4404
4405    /// Perform titlebar double-click action.
4406    /// This is macOS specific.
4407    pub fn titlebar_double_click(&self) {
4408        self.platform_window.titlebar_double_click();
4409    }
4410
4411    /// Gets the window's title at the platform level.
4412    /// This is macOS specific.
4413    pub fn window_title(&self) -> String {
4414        self.platform_window.get_title()
4415    }
4416
4417    /// Returns a list of all tabbed windows and their titles.
4418    /// This is macOS specific.
4419    pub fn tabbed_windows(&self) -> Option<Vec<SystemWindowTab>> {
4420        self.platform_window.tabbed_windows()
4421    }
4422
4423    /// Returns the tab bar visibility.
4424    /// This is macOS specific.
4425    pub fn tab_bar_visible(&self) -> bool {
4426        self.platform_window.tab_bar_visible()
4427    }
4428
4429    /// Merges all open windows into a single tabbed window.
4430    /// This is macOS specific.
4431    pub fn merge_all_windows(&self) {
4432        self.platform_window.merge_all_windows()
4433    }
4434
4435    /// Moves the tab to a new containing window.
4436    /// This is macOS specific.
4437    pub fn move_tab_to_new_window(&self) {
4438        self.platform_window.move_tab_to_new_window()
4439    }
4440
4441    /// Shows or hides the window tab overview.
4442    /// This is macOS specific.
4443    pub fn toggle_window_tab_overview(&self) {
4444        self.platform_window.toggle_window_tab_overview()
4445    }
4446
4447    /// Sets the tabbing identifier for the window.
4448    /// This is macOS specific.
4449    pub fn set_tabbing_identifier(&self, tabbing_identifier: Option<String>) {
4450        self.platform_window
4451            .set_tabbing_identifier(tabbing_identifier)
4452    }
4453
4454    /// Toggles the inspector mode on this window.
4455    #[cfg(any(feature = "inspector", debug_assertions))]
4456    pub fn toggle_inspector(&mut self, cx: &mut App) {
4457        self.inspector = match self.inspector {
4458            None => Some(cx.new(|_| Inspector::new())),
4459            Some(_) => None,
4460        };
4461        self.refresh();
4462    }
4463
4464    /// Returns true if the window is in inspector mode.
4465    pub fn is_inspector_picking(&self, _cx: &App) -> bool {
4466        #[cfg(any(feature = "inspector", debug_assertions))]
4467        {
4468            if let Some(inspector) = &self.inspector {
4469                return inspector.read(_cx).is_picking();
4470            }
4471        }
4472        false
4473    }
4474
4475    /// Executes the provided function with mutable access to an inspector state.
4476    #[cfg(any(feature = "inspector", debug_assertions))]
4477    pub fn with_inspector_state<T: 'static, R>(
4478        &mut self,
4479        _inspector_id: Option<&crate::InspectorElementId>,
4480        cx: &mut App,
4481        f: impl FnOnce(&mut Option<T>, &mut Self) -> R,
4482    ) -> R {
4483        if let Some(inspector_id) = _inspector_id
4484            && let Some(inspector) = &self.inspector
4485        {
4486            let inspector = inspector.clone();
4487            let active_element_id = inspector.read(cx).active_element_id();
4488            if Some(inspector_id) == active_element_id {
4489                return inspector.update(cx, |inspector, _cx| {
4490                    inspector.with_active_element_state(self, f)
4491                });
4492            }
4493        }
4494        f(&mut None, self)
4495    }
4496
4497    #[cfg(any(feature = "inspector", debug_assertions))]
4498    pub(crate) fn build_inspector_element_id(
4499        &mut self,
4500        path: crate::InspectorElementPath,
4501    ) -> crate::InspectorElementId {
4502        self.invalidator.debug_assert_paint_or_prepaint();
4503        let path = Rc::new(path);
4504        let next_instance_id = self
4505            .next_frame
4506            .next_inspector_instance_ids
4507            .entry(path.clone())
4508            .or_insert(0);
4509        let instance_id = *next_instance_id;
4510        *next_instance_id += 1;
4511        crate::InspectorElementId { path, instance_id }
4512    }
4513
4514    #[cfg(any(feature = "inspector", debug_assertions))]
4515    fn prepaint_inspector(&mut self, inspector_width: Pixels, cx: &mut App) -> Option<AnyElement> {
4516        if let Some(inspector) = self.inspector.take() {
4517            let mut inspector_element = AnyView::from(inspector.clone()).into_any_element();
4518            inspector_element.prepaint_as_root(
4519                point(self.viewport_size.width - inspector_width, px(0.0)),
4520                size(inspector_width, self.viewport_size.height).into(),
4521                self,
4522                cx,
4523            );
4524            self.inspector = Some(inspector);
4525            Some(inspector_element)
4526        } else {
4527            None
4528        }
4529    }
4530
4531    #[cfg(any(feature = "inspector", debug_assertions))]
4532    fn paint_inspector(&mut self, mut inspector_element: Option<AnyElement>, cx: &mut App) {
4533        if let Some(mut inspector_element) = inspector_element {
4534            inspector_element.paint(self, cx);
4535        };
4536    }
4537
4538    /// Registers a hitbox that can be used for inspector picking mode, allowing users to select and
4539    /// inspect UI elements by clicking on them.
4540    #[cfg(any(feature = "inspector", debug_assertions))]
4541    pub fn insert_inspector_hitbox(
4542        &mut self,
4543        hitbox_id: HitboxId,
4544        inspector_id: Option<&crate::InspectorElementId>,
4545        cx: &App,
4546    ) {
4547        self.invalidator.debug_assert_paint_or_prepaint();
4548        if !self.is_inspector_picking(cx) {
4549            return;
4550        }
4551        if let Some(inspector_id) = inspector_id {
4552            self.next_frame
4553                .inspector_hitboxes
4554                .insert(hitbox_id, inspector_id.clone());
4555        }
4556    }
4557
4558    #[cfg(any(feature = "inspector", debug_assertions))]
4559    fn paint_inspector_hitbox(&mut self, cx: &App) {
4560        if let Some(inspector) = self.inspector.as_ref() {
4561            let inspector = inspector.read(cx);
4562            if let Some((hitbox_id, _)) = self.hovered_inspector_hitbox(inspector, &self.next_frame)
4563                && let Some(hitbox) = self
4564                    .next_frame
4565                    .hitboxes
4566                    .iter()
4567                    .find(|hitbox| hitbox.id == hitbox_id)
4568            {
4569                self.paint_quad(crate::fill(hitbox.bounds, crate::rgba(0x61afef4d)));
4570            }
4571        }
4572    }
4573
4574    #[cfg(any(feature = "inspector", debug_assertions))]
4575    fn handle_inspector_mouse_event(&mut self, event: &dyn Any, cx: &mut App) {
4576        let Some(inspector) = self.inspector.clone() else {
4577            return;
4578        };
4579        if event.downcast_ref::<MouseMoveEvent>().is_some() {
4580            inspector.update(cx, |inspector, _cx| {
4581                if let Some((_, inspector_id)) =
4582                    self.hovered_inspector_hitbox(inspector, &self.rendered_frame)
4583                {
4584                    inspector.hover(inspector_id, self);
4585                }
4586            });
4587        } else if event.downcast_ref::<crate::MouseDownEvent>().is_some() {
4588            inspector.update(cx, |inspector, _cx| {
4589                if let Some((_, inspector_id)) =
4590                    self.hovered_inspector_hitbox(inspector, &self.rendered_frame)
4591                {
4592                    inspector.select(inspector_id, self);
4593                }
4594            });
4595        } else if let Some(event) = event.downcast_ref::<crate::ScrollWheelEvent>() {
4596            // This should be kept in sync with SCROLL_LINES in x11 platform.
4597            const SCROLL_LINES: f32 = 3.0;
4598            const SCROLL_PIXELS_PER_LAYER: f32 = 36.0;
4599            let delta_y = event
4600                .delta
4601                .pixel_delta(px(SCROLL_PIXELS_PER_LAYER / SCROLL_LINES))
4602                .y;
4603            if let Some(inspector) = self.inspector.clone() {
4604                inspector.update(cx, |inspector, _cx| {
4605                    if let Some(depth) = inspector.pick_depth.as_mut() {
4606                        *depth += f32::from(delta_y) / SCROLL_PIXELS_PER_LAYER;
4607                        let max_depth = self.mouse_hit_test.ids.len() as f32 - 0.5;
4608                        if *depth < 0.0 {
4609                            *depth = 0.0;
4610                        } else if *depth > max_depth {
4611                            *depth = max_depth;
4612                        }
4613                        if let Some((_, inspector_id)) =
4614                            self.hovered_inspector_hitbox(inspector, &self.rendered_frame)
4615                        {
4616                            inspector.set_active_element_id(inspector_id, self);
4617                        }
4618                    }
4619                });
4620            }
4621        }
4622    }
4623
4624    #[cfg(any(feature = "inspector", debug_assertions))]
4625    fn hovered_inspector_hitbox(
4626        &self,
4627        inspector: &Inspector,
4628        frame: &Frame,
4629    ) -> Option<(HitboxId, crate::InspectorElementId)> {
4630        if let Some(pick_depth) = inspector.pick_depth {
4631            let depth = (pick_depth as i64).try_into().unwrap_or(0);
4632            let max_skipped = self.mouse_hit_test.ids.len().saturating_sub(1);
4633            let skip_count = (depth as usize).min(max_skipped);
4634            for hitbox_id in self.mouse_hit_test.ids.iter().skip(skip_count) {
4635                if let Some(inspector_id) = frame.inspector_hitboxes.get(hitbox_id) {
4636                    return Some((*hitbox_id, inspector_id.clone()));
4637                }
4638            }
4639        }
4640        None
4641    }
4642
4643    /// For testing: set the current modifier keys state.
4644    /// This does not generate any events.
4645    #[cfg(any(test, feature = "test-support"))]
4646    pub fn set_modifiers(&mut self, modifiers: Modifiers) {
4647        self.modifiers = modifiers;
4648    }
4649}
4650
4651// #[derive(Clone, Copy, Eq, PartialEq, Hash)]
4652slotmap::new_key_type! {
4653    /// A unique identifier for a window.
4654    pub struct WindowId;
4655}
4656
4657impl WindowId {
4658    /// Converts this window ID to a `u64`.
4659    pub fn as_u64(&self) -> u64 {
4660        self.0.as_ffi()
4661    }
4662}
4663
4664impl From<u64> for WindowId {
4665    fn from(value: u64) -> Self {
4666        WindowId(slotmap::KeyData::from_ffi(value))
4667    }
4668}
4669
4670/// A handle to a window with a specific root view type.
4671/// Note that this does not keep the window alive on its own.
4672#[derive(Deref, DerefMut)]
4673pub struct WindowHandle<V> {
4674    #[deref]
4675    #[deref_mut]
4676    pub(crate) any_handle: AnyWindowHandle,
4677    state_type: PhantomData<fn(V) -> V>,
4678}
4679
4680impl<V> Debug for WindowHandle<V> {
4681    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
4682        f.debug_struct("WindowHandle")
4683            .field("any_handle", &self.any_handle.id.as_u64())
4684            .finish()
4685    }
4686}
4687
4688impl<V: 'static + Render> WindowHandle<V> {
4689    /// Creates a new handle from a window ID.
4690    /// This does not check if the root type of the window is `V`.
4691    pub fn new(id: WindowId) -> Self {
4692        WindowHandle {
4693            any_handle: AnyWindowHandle {
4694                id,
4695                state_type: TypeId::of::<V>(),
4696            },
4697            state_type: PhantomData,
4698        }
4699    }
4700
4701    /// Get the root view out of this window.
4702    ///
4703    /// This will fail if the window is closed or if the root view's type does not match `V`.
4704    #[cfg(any(test, feature = "test-support"))]
4705    pub fn root<C>(&self, cx: &mut C) -> Result<Entity<V>>
4706    where
4707        C: AppContext,
4708    {
4709        crate::Flatten::flatten(cx.update_window(self.any_handle, |root_view, _, _| {
4710            root_view
4711                .downcast::<V>()
4712                .map_err(|_| anyhow!("the type of the window's root view has changed"))
4713        }))
4714    }
4715
4716    /// Updates the root view of this window.
4717    ///
4718    /// This will fail if the window has been closed or if the root view's type does not match
4719    pub fn update<C, R>(
4720        &self,
4721        cx: &mut C,
4722        update: impl FnOnce(&mut V, &mut Window, &mut Context<V>) -> R,
4723    ) -> Result<R>
4724    where
4725        C: AppContext,
4726    {
4727        cx.update_window(self.any_handle, |root_view, window, cx| {
4728            let view = root_view
4729                .downcast::<V>()
4730                .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
4731
4732            Ok(view.update(cx, |view, cx| update(view, window, cx)))
4733        })?
4734    }
4735
4736    /// Read the root view out of this window.
4737    ///
4738    /// This will fail if the window is closed or if the root view's type does not match `V`.
4739    pub fn read<'a>(&self, cx: &'a App) -> Result<&'a V> {
4740        let x = cx
4741            .windows
4742            .get(self.id)
4743            .and_then(|window| {
4744                window
4745                    .as_deref()
4746                    .and_then(|window| window.root.clone())
4747                    .map(|root_view| root_view.downcast::<V>())
4748            })
4749            .context("window not found")?
4750            .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
4751
4752        Ok(x.read(cx))
4753    }
4754
4755    /// Read the root view out of this window, with a callback
4756    ///
4757    /// This will fail if the window is closed or if the root view's type does not match `V`.
4758    pub fn read_with<C, R>(&self, cx: &C, read_with: impl FnOnce(&V, &App) -> R) -> Result<R>
4759    where
4760        C: AppContext,
4761    {
4762        cx.read_window(self, |root_view, cx| read_with(root_view.read(cx), cx))
4763    }
4764
4765    /// Read the root view pointer off of this window.
4766    ///
4767    /// This will fail if the window is closed or if the root view's type does not match `V`.
4768    pub fn entity<C>(&self, cx: &C) -> Result<Entity<V>>
4769    where
4770        C: AppContext,
4771    {
4772        cx.read_window(self, |root_view, _cx| root_view)
4773    }
4774
4775    /// Check if this window is 'active'.
4776    ///
4777    /// Will return `None` if the window is closed or currently
4778    /// borrowed.
4779    pub fn is_active(&self, cx: &mut App) -> Option<bool> {
4780        cx.update_window(self.any_handle, |_, window, _| window.is_window_active())
4781            .ok()
4782    }
4783}
4784
4785impl<V> Copy for WindowHandle<V> {}
4786
4787impl<V> Clone for WindowHandle<V> {
4788    fn clone(&self) -> Self {
4789        *self
4790    }
4791}
4792
4793impl<V> PartialEq for WindowHandle<V> {
4794    fn eq(&self, other: &Self) -> bool {
4795        self.any_handle == other.any_handle
4796    }
4797}
4798
4799impl<V> Eq for WindowHandle<V> {}
4800
4801impl<V> Hash for WindowHandle<V> {
4802    fn hash<H: Hasher>(&self, state: &mut H) {
4803        self.any_handle.hash(state);
4804    }
4805}
4806
4807impl<V: 'static> From<WindowHandle<V>> for AnyWindowHandle {
4808    fn from(val: WindowHandle<V>) -> Self {
4809        val.any_handle
4810    }
4811}
4812
4813/// A handle to a window with any root view type, which can be downcast to a window with a specific root view type.
4814#[derive(Copy, Clone, PartialEq, Eq, Hash)]
4815pub struct AnyWindowHandle {
4816    pub(crate) id: WindowId,
4817    state_type: TypeId,
4818}
4819
4820impl AnyWindowHandle {
4821    /// Get the ID of this window.
4822    pub fn window_id(&self) -> WindowId {
4823        self.id
4824    }
4825
4826    /// Attempt to convert this handle to a window handle with a specific root view type.
4827    /// If the types do not match, this will return `None`.
4828    pub fn downcast<T: 'static>(&self) -> Option<WindowHandle<T>> {
4829        if TypeId::of::<T>() == self.state_type {
4830            Some(WindowHandle {
4831                any_handle: *self,
4832                state_type: PhantomData,
4833            })
4834        } else {
4835            None
4836        }
4837    }
4838
4839    /// Updates the state of the root view of this window.
4840    ///
4841    /// This will fail if the window has been closed.
4842    pub fn update<C, R>(
4843        self,
4844        cx: &mut C,
4845        update: impl FnOnce(AnyView, &mut Window, &mut App) -> R,
4846    ) -> Result<R>
4847    where
4848        C: AppContext,
4849    {
4850        cx.update_window(self, update)
4851    }
4852
4853    /// Read the state of the root view of this window.
4854    ///
4855    /// This will fail if the window has been closed.
4856    pub fn read<T, C, R>(self, cx: &C, read: impl FnOnce(Entity<T>, &App) -> R) -> Result<R>
4857    where
4858        C: AppContext,
4859        T: 'static,
4860    {
4861        let view = self
4862            .downcast::<T>()
4863            .context("the type of the window's root view has changed")?;
4864
4865        cx.read_window(&view, read)
4866    }
4867}
4868
4869impl HasWindowHandle for Window {
4870    fn window_handle(&self) -> Result<raw_window_handle::WindowHandle<'_>, HandleError> {
4871        self.platform_window.window_handle()
4872    }
4873}
4874
4875impl HasDisplayHandle for Window {
4876    fn display_handle(
4877        &self,
4878    ) -> std::result::Result<raw_window_handle::DisplayHandle<'_>, HandleError> {
4879        self.platform_window.display_handle()
4880    }
4881}
4882
4883/// An identifier for an [`Element`].
4884///
4885/// Can be constructed with a string, a number, or both, as well
4886/// as other internal representations.
4887#[derive(Clone, Debug, Eq, PartialEq, Hash)]
4888pub enum ElementId {
4889    /// The ID of a View element
4890    View(EntityId),
4891    /// An integer ID.
4892    Integer(u64),
4893    /// A string based ID.
4894    Name(SharedString),
4895    /// A UUID.
4896    Uuid(Uuid),
4897    /// An ID that's equated with a focus handle.
4898    FocusHandle(FocusId),
4899    /// A combination of a name and an integer.
4900    NamedInteger(SharedString, u64),
4901    /// A path.
4902    Path(Arc<std::path::Path>),
4903    /// A code location.
4904    CodeLocation(core::panic::Location<'static>),
4905    /// A labeled child of an element.
4906    NamedChild(Box<ElementId>, SharedString),
4907}
4908
4909impl ElementId {
4910    /// Constructs an `ElementId::NamedInteger` from a name and `usize`.
4911    pub fn named_usize(name: impl Into<SharedString>, integer: usize) -> ElementId {
4912        Self::NamedInteger(name.into(), integer as u64)
4913    }
4914}
4915
4916impl Display for ElementId {
4917    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
4918        match self {
4919            ElementId::View(entity_id) => write!(f, "view-{}", entity_id)?,
4920            ElementId::Integer(ix) => write!(f, "{}", ix)?,
4921            ElementId::Name(name) => write!(f, "{}", name)?,
4922            ElementId::FocusHandle(_) => write!(f, "FocusHandle")?,
4923            ElementId::NamedInteger(s, i) => write!(f, "{}-{}", s, i)?,
4924            ElementId::Uuid(uuid) => write!(f, "{}", uuid)?,
4925            ElementId::Path(path) => write!(f, "{}", path.display())?,
4926            ElementId::CodeLocation(location) => write!(f, "{}", location)?,
4927            ElementId::NamedChild(id, name) => write!(f, "{}-{}", id, name)?,
4928        }
4929
4930        Ok(())
4931    }
4932}
4933
4934impl TryInto<SharedString> for ElementId {
4935    type Error = anyhow::Error;
4936
4937    fn try_into(self) -> anyhow::Result<SharedString> {
4938        if let ElementId::Name(name) = self {
4939            Ok(name)
4940        } else {
4941            anyhow::bail!("element id is not string")
4942        }
4943    }
4944}
4945
4946impl From<usize> for ElementId {
4947    fn from(id: usize) -> Self {
4948        ElementId::Integer(id as u64)
4949    }
4950}
4951
4952impl From<i32> for ElementId {
4953    fn from(id: i32) -> Self {
4954        Self::Integer(id as u64)
4955    }
4956}
4957
4958impl From<SharedString> for ElementId {
4959    fn from(name: SharedString) -> Self {
4960        ElementId::Name(name)
4961    }
4962}
4963
4964impl From<Arc<std::path::Path>> for ElementId {
4965    fn from(path: Arc<std::path::Path>) -> Self {
4966        ElementId::Path(path)
4967    }
4968}
4969
4970impl From<&'static str> for ElementId {
4971    fn from(name: &'static str) -> Self {
4972        ElementId::Name(name.into())
4973    }
4974}
4975
4976impl<'a> From<&'a FocusHandle> for ElementId {
4977    fn from(handle: &'a FocusHandle) -> Self {
4978        ElementId::FocusHandle(handle.id)
4979    }
4980}
4981
4982impl From<(&'static str, EntityId)> for ElementId {
4983    fn from((name, id): (&'static str, EntityId)) -> Self {
4984        ElementId::NamedInteger(name.into(), id.as_u64())
4985    }
4986}
4987
4988impl From<(&'static str, usize)> for ElementId {
4989    fn from((name, id): (&'static str, usize)) -> Self {
4990        ElementId::NamedInteger(name.into(), id as u64)
4991    }
4992}
4993
4994impl From<(SharedString, usize)> for ElementId {
4995    fn from((name, id): (SharedString, usize)) -> Self {
4996        ElementId::NamedInteger(name, id as u64)
4997    }
4998}
4999
5000impl From<(&'static str, u64)> for ElementId {
5001    fn from((name, id): (&'static str, u64)) -> Self {
5002        ElementId::NamedInteger(name.into(), id)
5003    }
5004}
5005
5006impl From<Uuid> for ElementId {
5007    fn from(value: Uuid) -> Self {
5008        Self::Uuid(value)
5009    }
5010}
5011
5012impl From<(&'static str, u32)> for ElementId {
5013    fn from((name, id): (&'static str, u32)) -> Self {
5014        ElementId::NamedInteger(name.into(), id.into())
5015    }
5016}
5017
5018impl<T: Into<SharedString>> From<(ElementId, T)> for ElementId {
5019    fn from((id, name): (ElementId, T)) -> Self {
5020        ElementId::NamedChild(Box::new(id), name.into())
5021    }
5022}
5023
5024impl From<&'static core::panic::Location<'static>> for ElementId {
5025    fn from(location: &'static core::panic::Location<'static>) -> Self {
5026        ElementId::CodeLocation(*location)
5027    }
5028}
5029
5030/// A rectangle to be rendered in the window at the given position and size.
5031/// Passed as an argument [`Window::paint_quad`].
5032#[derive(Clone)]
5033pub struct PaintQuad {
5034    /// The bounds of the quad within the window.
5035    pub bounds: Bounds<Pixels>,
5036    /// The radii of the quad's corners.
5037    pub corner_radii: Corners<Pixels>,
5038    /// The background color of the quad.
5039    pub background: Background,
5040    /// The widths of the quad's borders.
5041    pub border_widths: Edges<Pixels>,
5042    /// The color of the quad's borders.
5043    pub border_color: Hsla,
5044    /// The style of the quad's borders.
5045    pub border_style: BorderStyle,
5046}
5047
5048impl PaintQuad {
5049    /// Sets the corner radii of the quad.
5050    pub fn corner_radii(self, corner_radii: impl Into<Corners<Pixels>>) -> Self {
5051        PaintQuad {
5052            corner_radii: corner_radii.into(),
5053            ..self
5054        }
5055    }
5056
5057    /// Sets the border widths of the quad.
5058    pub fn border_widths(self, border_widths: impl Into<Edges<Pixels>>) -> Self {
5059        PaintQuad {
5060            border_widths: border_widths.into(),
5061            ..self
5062        }
5063    }
5064
5065    /// Sets the border color of the quad.
5066    pub fn border_color(self, border_color: impl Into<Hsla>) -> Self {
5067        PaintQuad {
5068            border_color: border_color.into(),
5069            ..self
5070        }
5071    }
5072
5073    /// Sets the background color of the quad.
5074    pub fn background(self, background: impl Into<Background>) -> Self {
5075        PaintQuad {
5076            background: background.into(),
5077            ..self
5078        }
5079    }
5080}
5081
5082/// Creates a quad with the given parameters.
5083pub fn quad(
5084    bounds: Bounds<Pixels>,
5085    corner_radii: impl Into<Corners<Pixels>>,
5086    background: impl Into<Background>,
5087    border_widths: impl Into<Edges<Pixels>>,
5088    border_color: impl Into<Hsla>,
5089    border_style: BorderStyle,
5090) -> PaintQuad {
5091    PaintQuad {
5092        bounds,
5093        corner_radii: corner_radii.into(),
5094        background: background.into(),
5095        border_widths: border_widths.into(),
5096        border_color: border_color.into(),
5097        border_style,
5098    }
5099}
5100
5101/// Creates a filled quad with the given bounds and background color.
5102pub fn fill(bounds: impl Into<Bounds<Pixels>>, background: impl Into<Background>) -> PaintQuad {
5103    PaintQuad {
5104        bounds: bounds.into(),
5105        corner_radii: (0.).into(),
5106        background: background.into(),
5107        border_widths: (0.).into(),
5108        border_color: transparent_black(),
5109        border_style: BorderStyle::default(),
5110    }
5111}
5112
5113/// Creates a rectangle outline with the given bounds, border color, and a 1px border width
5114pub fn outline(
5115    bounds: impl Into<Bounds<Pixels>>,
5116    border_color: impl Into<Hsla>,
5117    border_style: BorderStyle,
5118) -> PaintQuad {
5119    PaintQuad {
5120        bounds: bounds.into(),
5121        corner_radii: (0.).into(),
5122        background: transparent_black().into(),
5123        border_widths: (1.).into(),
5124        border_color: border_color.into(),
5125        border_style,
5126    }
5127}