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_reversed(view_id)
1320        {
1321            if !self.dirty_views.insert(view_id) {
1322                break;
1323            }
1324        }
1325    }
1326
1327    /// Registers a callback to be invoked when the window appearance changes.
1328    pub fn observe_window_appearance(
1329        &self,
1330        mut callback: impl FnMut(&mut Window, &mut App) + 'static,
1331    ) -> Subscription {
1332        let (subscription, activate) = self.appearance_observers.insert(
1333            (),
1334            Box::new(move |window, cx| {
1335                callback(window, cx);
1336                true
1337            }),
1338        );
1339        activate();
1340        subscription
1341    }
1342
1343    /// Replaces the root entity of the window with a new one.
1344    pub fn replace_root<E>(
1345        &mut self,
1346        cx: &mut App,
1347        build_view: impl FnOnce(&mut Window, &mut Context<E>) -> E,
1348    ) -> Entity<E>
1349    where
1350        E: 'static + Render,
1351    {
1352        let view = cx.new(|cx| build_view(self, cx));
1353        self.root = Some(view.clone().into());
1354        self.refresh();
1355        view
1356    }
1357
1358    /// Returns the root entity of the window, if it has one.
1359    pub fn root<E>(&self) -> Option<Option<Entity<E>>>
1360    where
1361        E: 'static + Render,
1362    {
1363        self.root
1364            .as_ref()
1365            .map(|view| view.clone().downcast::<E>().ok())
1366    }
1367
1368    /// Obtain a handle to the window that belongs to this context.
1369    pub fn window_handle(&self) -> AnyWindowHandle {
1370        self.handle
1371    }
1372
1373    /// Mark the window as dirty, scheduling it to be redrawn on the next frame.
1374    pub fn refresh(&mut self) {
1375        if self.invalidator.not_drawing() {
1376            self.refreshing = true;
1377            self.invalidator.set_dirty(true);
1378        }
1379    }
1380
1381    /// Close this window.
1382    pub fn remove_window(&mut self) {
1383        self.removed = true;
1384    }
1385
1386    /// Obtain the currently focused [`FocusHandle`]. If no elements are focused, returns `None`.
1387    pub fn focused(&self, cx: &App) -> Option<FocusHandle> {
1388        self.focus
1389            .and_then(|id| FocusHandle::for_id(id, &cx.focus_handles))
1390    }
1391
1392    /// Move focus to the element associated with the given [`FocusHandle`].
1393    pub fn focus(&mut self, handle: &FocusHandle) {
1394        if !self.focus_enabled || self.focus == Some(handle.id) {
1395            return;
1396        }
1397
1398        self.focus = Some(handle.id);
1399        self.clear_pending_keystrokes();
1400        self.refresh();
1401    }
1402
1403    /// Remove focus from all elements within this context's window.
1404    pub fn blur(&mut self) {
1405        if !self.focus_enabled {
1406            return;
1407        }
1408
1409        self.focus = None;
1410        self.refresh();
1411    }
1412
1413    /// Blur the window and don't allow anything in it to be focused again.
1414    pub fn disable_focus(&mut self) {
1415        self.blur();
1416        self.focus_enabled = false;
1417    }
1418
1419    /// Move focus to next tab stop.
1420    pub fn focus_next(&mut self) {
1421        if !self.focus_enabled {
1422            return;
1423        }
1424
1425        if let Some(handle) = self.rendered_frame.tab_stops.next(self.focus.as_ref()) {
1426            self.focus(&handle)
1427        }
1428    }
1429
1430    /// Move focus to previous tab stop.
1431    pub fn focus_prev(&mut self) {
1432        if !self.focus_enabled {
1433            return;
1434        }
1435
1436        if let Some(handle) = self.rendered_frame.tab_stops.prev(self.focus.as_ref()) {
1437            self.focus(&handle)
1438        }
1439    }
1440
1441    /// Accessor for the text system.
1442    pub fn text_system(&self) -> &Arc<WindowTextSystem> {
1443        &self.text_system
1444    }
1445
1446    /// The current text style. Which is composed of all the style refinements provided to `with_text_style`.
1447    pub fn text_style(&self) -> TextStyle {
1448        let mut style = TextStyle::default();
1449        for refinement in &self.text_style_stack {
1450            style.refine(refinement);
1451        }
1452        style
1453    }
1454
1455    /// Check if the platform window is maximized
1456    /// On some platforms (namely Windows) this is different than the bounds being the size of the display
1457    pub fn is_maximized(&self) -> bool {
1458        self.platform_window.is_maximized()
1459    }
1460
1461    /// request a certain window decoration (Wayland)
1462    pub fn request_decorations(&self, decorations: WindowDecorations) {
1463        self.platform_window.request_decorations(decorations);
1464    }
1465
1466    /// Start a window resize operation (Wayland)
1467    pub fn start_window_resize(&self, edge: ResizeEdge) {
1468        self.platform_window.start_window_resize(edge);
1469    }
1470
1471    /// Return the `WindowBounds` to indicate that how a window should be opened
1472    /// after it has been closed
1473    pub fn window_bounds(&self) -> WindowBounds {
1474        self.platform_window.window_bounds()
1475    }
1476
1477    /// Return the `WindowBounds` excluding insets (Wayland and X11)
1478    pub fn inner_window_bounds(&self) -> WindowBounds {
1479        self.platform_window.inner_window_bounds()
1480    }
1481
1482    /// Dispatch the given action on the currently focused element.
1483    pub fn dispatch_action(&mut self, action: Box<dyn Action>, cx: &mut App) {
1484        let focus_id = self.focused(cx).map(|handle| handle.id);
1485
1486        let window = self.handle;
1487        cx.defer(move |cx| {
1488            window
1489                .update(cx, |_, window, cx| {
1490                    let node_id = window.focus_node_id_in_rendered_frame(focus_id);
1491                    window.dispatch_action_on_node(node_id, action.as_ref(), cx);
1492                })
1493                .log_err();
1494        })
1495    }
1496
1497    pub(crate) fn dispatch_keystroke_observers(
1498        &mut self,
1499        event: &dyn Any,
1500        action: Option<Box<dyn Action>>,
1501        context_stack: Vec<KeyContext>,
1502        cx: &mut App,
1503    ) {
1504        let Some(key_down_event) = event.downcast_ref::<KeyDownEvent>() else {
1505            return;
1506        };
1507
1508        cx.keystroke_observers.clone().retain(&(), move |callback| {
1509            (callback)(
1510                &KeystrokeEvent {
1511                    keystroke: key_down_event.keystroke.clone(),
1512                    action: action.as_ref().map(|action| action.boxed_clone()),
1513                    context_stack: context_stack.clone(),
1514                },
1515                self,
1516                cx,
1517            )
1518        });
1519    }
1520
1521    pub(crate) fn dispatch_keystroke_interceptors(
1522        &mut self,
1523        event: &dyn Any,
1524        context_stack: Vec<KeyContext>,
1525        cx: &mut App,
1526    ) {
1527        let Some(key_down_event) = event.downcast_ref::<KeyDownEvent>() else {
1528            return;
1529        };
1530
1531        cx.keystroke_interceptors
1532            .clone()
1533            .retain(&(), move |callback| {
1534                (callback)(
1535                    &KeystrokeEvent {
1536                        keystroke: key_down_event.keystroke.clone(),
1537                        action: None,
1538                        context_stack: context_stack.clone(),
1539                    },
1540                    self,
1541                    cx,
1542                )
1543            });
1544    }
1545
1546    /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
1547    /// that are currently on the stack to be returned to the app.
1548    pub fn defer(&self, cx: &mut App, f: impl FnOnce(&mut Window, &mut App) + 'static) {
1549        let handle = self.handle;
1550        cx.defer(move |cx| {
1551            handle.update(cx, |_, window, cx| f(window, cx)).ok();
1552        });
1553    }
1554
1555    /// Subscribe to events emitted by a entity.
1556    /// The entity to which you're subscribing must implement the [`EventEmitter`] trait.
1557    /// The callback will be invoked a handle to the emitting entity, the event, and a window context for the current window.
1558    pub fn observe<T: 'static>(
1559        &mut self,
1560        observed: &Entity<T>,
1561        cx: &mut App,
1562        mut on_notify: impl FnMut(Entity<T>, &mut Window, &mut App) + 'static,
1563    ) -> Subscription {
1564        let entity_id = observed.entity_id();
1565        let observed = observed.downgrade();
1566        let window_handle = self.handle;
1567        cx.new_observer(
1568            entity_id,
1569            Box::new(move |cx| {
1570                window_handle
1571                    .update(cx, |_, window, cx| {
1572                        if let Some(handle) = observed.upgrade() {
1573                            on_notify(handle, window, cx);
1574                            true
1575                        } else {
1576                            false
1577                        }
1578                    })
1579                    .unwrap_or(false)
1580            }),
1581        )
1582    }
1583
1584    /// Subscribe to events emitted by a entity.
1585    /// The entity to which you're subscribing must implement the [`EventEmitter`] trait.
1586    /// The callback will be invoked a handle to the emitting entity, the event, and a window context for the current window.
1587    pub fn subscribe<Emitter, Evt>(
1588        &mut self,
1589        entity: &Entity<Emitter>,
1590        cx: &mut App,
1591        mut on_event: impl FnMut(Entity<Emitter>, &Evt, &mut Window, &mut App) + 'static,
1592    ) -> Subscription
1593    where
1594        Emitter: EventEmitter<Evt>,
1595        Evt: 'static,
1596    {
1597        let entity_id = entity.entity_id();
1598        let handle = entity.downgrade();
1599        let window_handle = self.handle;
1600        cx.new_subscription(
1601            entity_id,
1602            (
1603                TypeId::of::<Evt>(),
1604                Box::new(move |event, cx| {
1605                    window_handle
1606                        .update(cx, |_, window, cx| {
1607                            if let Some(entity) = handle.upgrade() {
1608                                let event = event.downcast_ref().expect("invalid event type");
1609                                on_event(entity, event, window, cx);
1610                                true
1611                            } else {
1612                                false
1613                            }
1614                        })
1615                        .unwrap_or(false)
1616                }),
1617            ),
1618        )
1619    }
1620
1621    /// Register a callback to be invoked when the given `Entity` is released.
1622    pub fn observe_release<T>(
1623        &self,
1624        entity: &Entity<T>,
1625        cx: &mut App,
1626        mut on_release: impl FnOnce(&mut T, &mut Window, &mut App) + 'static,
1627    ) -> Subscription
1628    where
1629        T: 'static,
1630    {
1631        let entity_id = entity.entity_id();
1632        let window_handle = self.handle;
1633        let (subscription, activate) = cx.release_listeners.insert(
1634            entity_id,
1635            Box::new(move |entity, cx| {
1636                let entity = entity.downcast_mut().expect("invalid entity type");
1637                let _ = window_handle.update(cx, |_, window, cx| on_release(entity, window, cx));
1638            }),
1639        );
1640        activate();
1641        subscription
1642    }
1643
1644    /// Creates an [`AsyncWindowContext`], which has a static lifetime and can be held across
1645    /// await points in async code.
1646    pub fn to_async(&self, cx: &App) -> AsyncWindowContext {
1647        AsyncWindowContext::new_context(cx.to_async(), self.handle)
1648    }
1649
1650    /// Schedule the given closure to be run directly after the current frame is rendered.
1651    pub fn on_next_frame(&self, callback: impl FnOnce(&mut Window, &mut App) + 'static) {
1652        RefCell::borrow_mut(&self.next_frame_callbacks).push(Box::new(callback));
1653    }
1654
1655    /// Schedule a frame to be drawn on the next animation frame.
1656    ///
1657    /// This is useful for elements that need to animate continuously, such as a video player or an animated GIF.
1658    /// It will cause the window to redraw on the next frame, even if no other changes have occurred.
1659    ///
1660    /// If called from within a view, it will notify that view on the next frame. Otherwise, it will refresh the entire window.
1661    pub fn request_animation_frame(&self) {
1662        let entity = self.current_view();
1663        self.on_next_frame(move |_, cx| cx.notify(entity));
1664    }
1665
1666    /// Spawn the future returned by the given closure on the application thread pool.
1667    /// The closure is provided a handle to the current window and an `AsyncWindowContext` for
1668    /// use within your future.
1669    #[track_caller]
1670    pub fn spawn<AsyncFn, R>(&self, cx: &App, f: AsyncFn) -> Task<R>
1671    where
1672        R: 'static,
1673        AsyncFn: AsyncFnOnce(&mut AsyncWindowContext) -> R + 'static,
1674    {
1675        let handle = self.handle;
1676        cx.spawn(async move |app| {
1677            let mut async_window_cx = AsyncWindowContext::new_context(app.clone(), handle);
1678            f(&mut async_window_cx).await
1679        })
1680    }
1681
1682    fn bounds_changed(&mut self, cx: &mut App) {
1683        self.scale_factor = self.platform_window.scale_factor();
1684        self.viewport_size = self.platform_window.content_size();
1685        self.display_id = self.platform_window.display().map(|display| display.id());
1686
1687        self.refresh();
1688
1689        self.bounds_observers
1690            .clone()
1691            .retain(&(), |callback| callback(self, cx));
1692    }
1693
1694    /// Returns the bounds of the current window in the global coordinate space, which could span across multiple displays.
1695    pub fn bounds(&self) -> Bounds<Pixels> {
1696        self.platform_window.bounds()
1697    }
1698
1699    /// Set the content size of the window.
1700    pub fn resize(&mut self, size: Size<Pixels>) {
1701        self.platform_window.resize(size);
1702    }
1703
1704    /// Returns whether or not the window is currently fullscreen
1705    pub fn is_fullscreen(&self) -> bool {
1706        self.platform_window.is_fullscreen()
1707    }
1708
1709    pub(crate) fn appearance_changed(&mut self, cx: &mut App) {
1710        self.appearance = self.platform_window.appearance();
1711
1712        self.appearance_observers
1713            .clone()
1714            .retain(&(), |callback| callback(self, cx));
1715    }
1716
1717    /// Returns the appearance of the current window.
1718    pub fn appearance(&self) -> WindowAppearance {
1719        self.appearance
1720    }
1721
1722    /// Returns the size of the drawable area within the window.
1723    pub fn viewport_size(&self) -> Size<Pixels> {
1724        self.viewport_size
1725    }
1726
1727    /// Returns whether this window is focused by the operating system (receiving key events).
1728    pub fn is_window_active(&self) -> bool {
1729        self.active.get()
1730    }
1731
1732    /// Returns whether this window is considered to be the window
1733    /// that currently owns the mouse cursor.
1734    /// On mac, this is equivalent to `is_window_active`.
1735    pub fn is_window_hovered(&self) -> bool {
1736        if cfg!(any(
1737            target_os = "windows",
1738            target_os = "linux",
1739            target_os = "freebsd"
1740        )) {
1741            self.hovered.get()
1742        } else {
1743            self.is_window_active()
1744        }
1745    }
1746
1747    /// Toggle zoom on the window.
1748    pub fn zoom_window(&self) {
1749        self.platform_window.zoom();
1750    }
1751
1752    /// Opens the native title bar context menu, useful when implementing client side decorations (Wayland and X11)
1753    pub fn show_window_menu(&self, position: Point<Pixels>) {
1754        self.platform_window.show_window_menu(position)
1755    }
1756
1757    /// Tells the compositor to take control of window movement (Wayland and X11)
1758    ///
1759    /// Events may not be received during a move operation.
1760    pub fn start_window_move(&self) {
1761        self.platform_window.start_window_move()
1762    }
1763
1764    /// When using client side decorations, set this to the width of the invisible decorations (Wayland and X11)
1765    pub fn set_client_inset(&mut self, inset: Pixels) {
1766        self.client_inset = Some(inset);
1767        self.platform_window.set_client_inset(inset);
1768    }
1769
1770    /// Returns the client_inset value by [`Self::set_client_inset`].
1771    pub fn client_inset(&self) -> Option<Pixels> {
1772        self.client_inset
1773    }
1774
1775    /// Returns whether the title bar window controls need to be rendered by the application (Wayland and X11)
1776    pub fn window_decorations(&self) -> Decorations {
1777        self.platform_window.window_decorations()
1778    }
1779
1780    /// Returns which window controls are currently visible (Wayland)
1781    pub fn window_controls(&self) -> WindowControls {
1782        self.platform_window.window_controls()
1783    }
1784
1785    /// Updates the window's title at the platform level.
1786    pub fn set_window_title(&mut self, title: &str) {
1787        self.platform_window.set_title(title);
1788    }
1789
1790    /// Sets the application identifier.
1791    pub fn set_app_id(&mut self, app_id: &str) {
1792        self.platform_window.set_app_id(app_id);
1793    }
1794
1795    /// Sets the window background appearance.
1796    pub fn set_background_appearance(&self, background_appearance: WindowBackgroundAppearance) {
1797        self.platform_window
1798            .set_background_appearance(background_appearance);
1799    }
1800
1801    /// Mark the window as dirty at the platform level.
1802    pub fn set_window_edited(&mut self, edited: bool) {
1803        self.platform_window.set_edited(edited);
1804    }
1805
1806    /// Determine the display on which the window is visible.
1807    pub fn display(&self, cx: &App) -> Option<Rc<dyn PlatformDisplay>> {
1808        cx.platform
1809            .displays()
1810            .into_iter()
1811            .find(|display| Some(display.id()) == self.display_id)
1812    }
1813
1814    /// Show the platform character palette.
1815    pub fn show_character_palette(&self) {
1816        self.platform_window.show_character_palette();
1817    }
1818
1819    /// The scale factor of the display associated with the window. For example, it could
1820    /// return 2.0 for a "retina" display, indicating that each logical pixel should actually
1821    /// be rendered as two pixels on screen.
1822    pub fn scale_factor(&self) -> f32 {
1823        self.scale_factor
1824    }
1825
1826    /// The size of an em for the base font of the application. Adjusting this value allows the
1827    /// UI to scale, just like zooming a web page.
1828    pub fn rem_size(&self) -> Pixels {
1829        self.rem_size_override_stack
1830            .last()
1831            .copied()
1832            .unwrap_or(self.rem_size)
1833    }
1834
1835    /// Sets the size of an em for the base font of the application. Adjusting this value allows the
1836    /// UI to scale, just like zooming a web page.
1837    pub fn set_rem_size(&mut self, rem_size: impl Into<Pixels>) {
1838        self.rem_size = rem_size.into();
1839    }
1840
1841    /// Acquire a globally unique identifier for the given ElementId.
1842    /// Only valid for the duration of the provided closure.
1843    pub fn with_global_id<R>(
1844        &mut self,
1845        element_id: ElementId,
1846        f: impl FnOnce(&GlobalElementId, &mut Self) -> R,
1847    ) -> R {
1848        self.element_id_stack.push(element_id);
1849        let global_id = GlobalElementId(Arc::from(&*self.element_id_stack));
1850
1851        let result = f(&global_id, self);
1852        self.element_id_stack.pop();
1853        result
1854    }
1855
1856    /// Executes the provided function with the specified rem size.
1857    ///
1858    /// This method must only be called as part of element drawing.
1859    pub fn with_rem_size<F, R>(&mut self, rem_size: Option<impl Into<Pixels>>, f: F) -> R
1860    where
1861        F: FnOnce(&mut Self) -> R,
1862    {
1863        self.invalidator.debug_assert_paint_or_prepaint();
1864
1865        if let Some(rem_size) = rem_size {
1866            self.rem_size_override_stack.push(rem_size.into());
1867            let result = f(self);
1868            self.rem_size_override_stack.pop();
1869            result
1870        } else {
1871            f(self)
1872        }
1873    }
1874
1875    /// The line height associated with the current text style.
1876    pub fn line_height(&self) -> Pixels {
1877        self.text_style().line_height_in_pixels(self.rem_size())
1878    }
1879
1880    /// Call to prevent the default action of an event. Currently only used to prevent
1881    /// parent elements from becoming focused on mouse down.
1882    pub fn prevent_default(&mut self) {
1883        self.default_prevented = true;
1884    }
1885
1886    /// Obtain whether default has been prevented for the event currently being dispatched.
1887    pub fn default_prevented(&self) -> bool {
1888        self.default_prevented
1889    }
1890
1891    /// Determine whether the given action is available along the dispatch path to the currently focused element.
1892    pub fn is_action_available(&self, action: &dyn Action, cx: &mut App) -> bool {
1893        let node_id =
1894            self.focus_node_id_in_rendered_frame(self.focused(cx).map(|handle| handle.id));
1895        self.rendered_frame
1896            .dispatch_tree
1897            .is_action_available(action, node_id)
1898    }
1899
1900    /// The position of the mouse relative to the window.
1901    pub fn mouse_position(&self) -> Point<Pixels> {
1902        self.mouse_position
1903    }
1904
1905    /// The current state of the keyboard's modifiers
1906    pub fn modifiers(&self) -> Modifiers {
1907        self.modifiers
1908    }
1909
1910    /// Returns true if the last input event was keyboard-based (key press, tab navigation, etc.)
1911    /// This is used for focus-visible styling to show focus indicators only for keyboard navigation.
1912    pub fn last_input_was_keyboard(&self) -> bool {
1913        self.last_input_was_keyboard
1914    }
1915
1916    /// The current state of the keyboard's capslock
1917    pub fn capslock(&self) -> Capslock {
1918        self.capslock
1919    }
1920
1921    fn complete_frame(&self) {
1922        self.platform_window.completed_frame();
1923    }
1924
1925    /// Produces a new frame and assigns it to `rendered_frame`. To actually show
1926    /// the contents of the new [`Scene`], use [`Self::present`].
1927    #[profiling::function]
1928    pub fn draw(&mut self, cx: &mut App) -> ArenaClearNeeded {
1929        self.invalidate_entities();
1930        cx.entities.clear_accessed();
1931        debug_assert!(self.rendered_entity_stack.is_empty());
1932        self.invalidator.set_dirty(false);
1933        self.requested_autoscroll = None;
1934
1935        // Restore the previously-used input handler.
1936        if let Some(input_handler) = self.platform_window.take_input_handler() {
1937            self.rendered_frame.input_handlers.push(Some(input_handler));
1938        }
1939        self.draw_roots(cx);
1940        self.dirty_views.clear();
1941        self.next_frame.window_active = self.active.get();
1942
1943        // Register requested input handler with the platform window.
1944        if let Some(input_handler) = self.next_frame.input_handlers.pop() {
1945            self.platform_window
1946                .set_input_handler(input_handler.unwrap());
1947        }
1948
1949        self.layout_engine.as_mut().unwrap().clear();
1950        self.text_system().finish_frame();
1951        self.next_frame.finish(&mut self.rendered_frame);
1952
1953        self.invalidator.set_phase(DrawPhase::Focus);
1954        let previous_focus_path = self.rendered_frame.focus_path();
1955        let previous_window_active = self.rendered_frame.window_active;
1956        mem::swap(&mut self.rendered_frame, &mut self.next_frame);
1957        self.next_frame.clear();
1958        let current_focus_path = self.rendered_frame.focus_path();
1959        let current_window_active = self.rendered_frame.window_active;
1960
1961        if previous_focus_path != current_focus_path
1962            || previous_window_active != current_window_active
1963        {
1964            if !previous_focus_path.is_empty() && current_focus_path.is_empty() {
1965                self.focus_lost_listeners
1966                    .clone()
1967                    .retain(&(), |listener| listener(self, cx));
1968            }
1969
1970            let event = WindowFocusEvent {
1971                previous_focus_path: if previous_window_active {
1972                    previous_focus_path
1973                } else {
1974                    Default::default()
1975                },
1976                current_focus_path: if current_window_active {
1977                    current_focus_path
1978                } else {
1979                    Default::default()
1980                },
1981            };
1982            self.focus_listeners
1983                .clone()
1984                .retain(&(), |listener| listener(&event, self, cx));
1985        }
1986
1987        debug_assert!(self.rendered_entity_stack.is_empty());
1988        self.record_entities_accessed(cx);
1989        self.reset_cursor_style(cx);
1990        self.refreshing = false;
1991        self.invalidator.set_phase(DrawPhase::None);
1992        self.needs_present.set(true);
1993
1994        ArenaClearNeeded
1995    }
1996
1997    fn record_entities_accessed(&mut self, cx: &mut App) {
1998        let mut entities_ref = cx.entities.accessed_entities.borrow_mut();
1999        let mut entities = mem::take(entities_ref.deref_mut());
2000        drop(entities_ref);
2001        let handle = self.handle;
2002        cx.record_entities_accessed(
2003            handle,
2004            // Try moving window invalidator into the Window
2005            self.invalidator.clone(),
2006            &entities,
2007        );
2008        let mut entities_ref = cx.entities.accessed_entities.borrow_mut();
2009        mem::swap(&mut entities, entities_ref.deref_mut());
2010    }
2011
2012    fn invalidate_entities(&mut self) {
2013        let mut views = self.invalidator.take_views();
2014        for entity in views.drain() {
2015            self.mark_view_dirty(entity);
2016        }
2017        self.invalidator.replace_views(views);
2018    }
2019
2020    #[profiling::function]
2021    fn present(&self) {
2022        self.platform_window.draw(&self.rendered_frame.scene);
2023        self.needs_present.set(false);
2024        profiling::finish_frame!();
2025    }
2026
2027    fn draw_roots(&mut self, cx: &mut App) {
2028        self.invalidator.set_phase(DrawPhase::Prepaint);
2029        self.tooltip_bounds.take();
2030
2031        let _inspector_width: Pixels = rems(30.0).to_pixels(self.rem_size());
2032        let root_size = {
2033            #[cfg(any(feature = "inspector", debug_assertions))]
2034            {
2035                if self.inspector.is_some() {
2036                    let mut size = self.viewport_size;
2037                    size.width = (size.width - _inspector_width).max(px(0.0));
2038                    size
2039                } else {
2040                    self.viewport_size
2041                }
2042            }
2043            #[cfg(not(any(feature = "inspector", debug_assertions)))]
2044            {
2045                self.viewport_size
2046            }
2047        };
2048
2049        // Layout all root elements.
2050        let mut root_element = self.root.as_ref().unwrap().clone().into_any();
2051        root_element.prepaint_as_root(Point::default(), root_size.into(), self, cx);
2052
2053        #[cfg(any(feature = "inspector", debug_assertions))]
2054        let inspector_element = self.prepaint_inspector(_inspector_width, cx);
2055
2056        let mut sorted_deferred_draws =
2057            (0..self.next_frame.deferred_draws.len()).collect::<SmallVec<[_; 8]>>();
2058        sorted_deferred_draws.sort_by_key(|ix| self.next_frame.deferred_draws[*ix].priority);
2059        self.prepaint_deferred_draws(&sorted_deferred_draws, cx);
2060
2061        let mut prompt_element = None;
2062        let mut active_drag_element = None;
2063        let mut tooltip_element = None;
2064        if let Some(prompt) = self.prompt.take() {
2065            let mut element = prompt.view.any_view().into_any();
2066            element.prepaint_as_root(Point::default(), root_size.into(), self, cx);
2067            prompt_element = Some(element);
2068            self.prompt = Some(prompt);
2069        } else if let Some(active_drag) = cx.active_drag.take() {
2070            let mut element = active_drag.view.clone().into_any();
2071            let offset = self.mouse_position() - active_drag.cursor_offset;
2072            element.prepaint_as_root(offset, AvailableSpace::min_size(), self, cx);
2073            active_drag_element = Some(element);
2074            cx.active_drag = Some(active_drag);
2075        } else {
2076            tooltip_element = self.prepaint_tooltip(cx);
2077        }
2078
2079        self.mouse_hit_test = self.next_frame.hit_test(self.mouse_position);
2080
2081        // Now actually paint the elements.
2082        self.invalidator.set_phase(DrawPhase::Paint);
2083        root_element.paint(self, cx);
2084
2085        #[cfg(any(feature = "inspector", debug_assertions))]
2086        self.paint_inspector(inspector_element, cx);
2087
2088        self.paint_deferred_draws(&sorted_deferred_draws, cx);
2089
2090        if let Some(mut prompt_element) = prompt_element {
2091            prompt_element.paint(self, cx);
2092        } else if let Some(mut drag_element) = active_drag_element {
2093            drag_element.paint(self, cx);
2094        } else if let Some(mut tooltip_element) = tooltip_element {
2095            tooltip_element.paint(self, cx);
2096        }
2097
2098        #[cfg(any(feature = "inspector", debug_assertions))]
2099        self.paint_inspector_hitbox(cx);
2100    }
2101
2102    fn prepaint_tooltip(&mut self, cx: &mut App) -> Option<AnyElement> {
2103        // Use indexing instead of iteration to avoid borrowing self for the duration of the loop.
2104        for tooltip_request_index in (0..self.next_frame.tooltip_requests.len()).rev() {
2105            let Some(Some(tooltip_request)) = self
2106                .next_frame
2107                .tooltip_requests
2108                .get(tooltip_request_index)
2109                .cloned()
2110            else {
2111                log::error!("Unexpectedly absent TooltipRequest");
2112                continue;
2113            };
2114            let mut element = tooltip_request.tooltip.view.clone().into_any();
2115            let mouse_position = tooltip_request.tooltip.mouse_position;
2116            let tooltip_size = element.layout_as_root(AvailableSpace::min_size(), self, cx);
2117
2118            let mut tooltip_bounds =
2119                Bounds::new(mouse_position + point(px(1.), px(1.)), tooltip_size);
2120            let window_bounds = Bounds {
2121                origin: Point::default(),
2122                size: self.viewport_size(),
2123            };
2124
2125            if tooltip_bounds.right() > window_bounds.right() {
2126                let new_x = mouse_position.x - tooltip_bounds.size.width - px(1.);
2127                if new_x >= Pixels::ZERO {
2128                    tooltip_bounds.origin.x = new_x;
2129                } else {
2130                    tooltip_bounds.origin.x = cmp::max(
2131                        Pixels::ZERO,
2132                        tooltip_bounds.origin.x - tooltip_bounds.right() - window_bounds.right(),
2133                    );
2134                }
2135            }
2136
2137            if tooltip_bounds.bottom() > window_bounds.bottom() {
2138                let new_y = mouse_position.y - tooltip_bounds.size.height - px(1.);
2139                if new_y >= Pixels::ZERO {
2140                    tooltip_bounds.origin.y = new_y;
2141                } else {
2142                    tooltip_bounds.origin.y = cmp::max(
2143                        Pixels::ZERO,
2144                        tooltip_bounds.origin.y - tooltip_bounds.bottom() - window_bounds.bottom(),
2145                    );
2146                }
2147            }
2148
2149            // It's possible for an element to have an active tooltip while not being painted (e.g.
2150            // via the `visible_on_hover` method). Since mouse listeners are not active in this
2151            // case, instead update the tooltip's visibility here.
2152            let is_visible =
2153                (tooltip_request.tooltip.check_visible_and_update)(tooltip_bounds, self, cx);
2154            if !is_visible {
2155                continue;
2156            }
2157
2158            self.with_absolute_element_offset(tooltip_bounds.origin, |window| {
2159                element.prepaint(window, cx)
2160            });
2161
2162            self.tooltip_bounds = Some(TooltipBounds {
2163                id: tooltip_request.id,
2164                bounds: tooltip_bounds,
2165            });
2166            return Some(element);
2167        }
2168        None
2169    }
2170
2171    fn prepaint_deferred_draws(&mut self, deferred_draw_indices: &[usize], cx: &mut App) {
2172        assert_eq!(self.element_id_stack.len(), 0);
2173
2174        let mut deferred_draws = mem::take(&mut self.next_frame.deferred_draws);
2175        for deferred_draw_ix in deferred_draw_indices {
2176            let deferred_draw = &mut deferred_draws[*deferred_draw_ix];
2177            self.element_id_stack
2178                .clone_from(&deferred_draw.element_id_stack);
2179            self.text_style_stack
2180                .clone_from(&deferred_draw.text_style_stack);
2181            self.next_frame
2182                .dispatch_tree
2183                .set_active_node(deferred_draw.parent_node);
2184
2185            let prepaint_start = self.prepaint_index();
2186            if let Some(element) = deferred_draw.element.as_mut() {
2187                self.with_rendered_view(deferred_draw.current_view, |window| {
2188                    window.with_absolute_element_offset(deferred_draw.absolute_offset, |window| {
2189                        element.prepaint(window, cx)
2190                    });
2191                })
2192            } else {
2193                self.reuse_prepaint(deferred_draw.prepaint_range.clone());
2194            }
2195            let prepaint_end = self.prepaint_index();
2196            deferred_draw.prepaint_range = prepaint_start..prepaint_end;
2197        }
2198        assert_eq!(
2199            self.next_frame.deferred_draws.len(),
2200            0,
2201            "cannot call defer_draw during deferred drawing"
2202        );
2203        self.next_frame.deferred_draws = deferred_draws;
2204        self.element_id_stack.clear();
2205        self.text_style_stack.clear();
2206    }
2207
2208    fn paint_deferred_draws(&mut self, deferred_draw_indices: &[usize], cx: &mut App) {
2209        assert_eq!(self.element_id_stack.len(), 0);
2210
2211        let mut deferred_draws = mem::take(&mut self.next_frame.deferred_draws);
2212        for deferred_draw_ix in deferred_draw_indices {
2213            let mut deferred_draw = &mut deferred_draws[*deferred_draw_ix];
2214            self.element_id_stack
2215                .clone_from(&deferred_draw.element_id_stack);
2216            self.next_frame
2217                .dispatch_tree
2218                .set_active_node(deferred_draw.parent_node);
2219
2220            let paint_start = self.paint_index();
2221            if let Some(element) = deferred_draw.element.as_mut() {
2222                self.with_rendered_view(deferred_draw.current_view, |window| {
2223                    element.paint(window, cx);
2224                })
2225            } else {
2226                self.reuse_paint(deferred_draw.paint_range.clone());
2227            }
2228            let paint_end = self.paint_index();
2229            deferred_draw.paint_range = paint_start..paint_end;
2230        }
2231        self.next_frame.deferred_draws = deferred_draws;
2232        self.element_id_stack.clear();
2233    }
2234
2235    pub(crate) fn prepaint_index(&self) -> PrepaintStateIndex {
2236        PrepaintStateIndex {
2237            hitboxes_index: self.next_frame.hitboxes.len(),
2238            tooltips_index: self.next_frame.tooltip_requests.len(),
2239            deferred_draws_index: self.next_frame.deferred_draws.len(),
2240            dispatch_tree_index: self.next_frame.dispatch_tree.len(),
2241            accessed_element_states_index: self.next_frame.accessed_element_states.len(),
2242            line_layout_index: self.text_system.layout_index(),
2243        }
2244    }
2245
2246    pub(crate) fn reuse_prepaint(&mut self, range: Range<PrepaintStateIndex>) {
2247        self.next_frame.hitboxes.extend(
2248            self.rendered_frame.hitboxes[range.start.hitboxes_index..range.end.hitboxes_index]
2249                .iter()
2250                .cloned(),
2251        );
2252        self.next_frame.tooltip_requests.extend(
2253            self.rendered_frame.tooltip_requests
2254                [range.start.tooltips_index..range.end.tooltips_index]
2255                .iter_mut()
2256                .map(|request| request.take()),
2257        );
2258        self.next_frame.accessed_element_states.extend(
2259            self.rendered_frame.accessed_element_states[range.start.accessed_element_states_index
2260                ..range.end.accessed_element_states_index]
2261                .iter()
2262                .map(|(id, type_id)| (id.clone(), *type_id)),
2263        );
2264        self.text_system
2265            .reuse_layouts(range.start.line_layout_index..range.end.line_layout_index);
2266
2267        let reused_subtree = self.next_frame.dispatch_tree.reuse_subtree(
2268            range.start.dispatch_tree_index..range.end.dispatch_tree_index,
2269            &mut self.rendered_frame.dispatch_tree,
2270            self.focus,
2271        );
2272
2273        if reused_subtree.contains_focus() {
2274            self.next_frame.focus = self.focus;
2275        }
2276
2277        self.next_frame.deferred_draws.extend(
2278            self.rendered_frame
2279                .deferred_draws
2280                .drain(range.start.deferred_draws_index..range.end.deferred_draws_index)
2281                .map(|mut deferred_draw| {
2282                    deferred_draw.parent_node =
2283                        reused_subtree.refresh_node_id(deferred_draw.parent_node);
2284                    deferred_draw.element = None;
2285                    deferred_draw
2286                }),
2287        );
2288    }
2289
2290    pub(crate) fn paint_index(&self) -> PaintIndex {
2291        PaintIndex {
2292            scene_index: self.next_frame.scene.len(),
2293            mouse_listeners_index: self.next_frame.mouse_listeners.len(),
2294            input_handlers_index: self.next_frame.input_handlers.len(),
2295            cursor_styles_index: self.next_frame.cursor_styles.len(),
2296            accessed_element_states_index: self.next_frame.accessed_element_states.len(),
2297            tab_handle_index: self.next_frame.tab_stops.paint_index(),
2298            line_layout_index: self.text_system.layout_index(),
2299        }
2300    }
2301
2302    pub(crate) fn reuse_paint(&mut self, range: Range<PaintIndex>) {
2303        self.next_frame.cursor_styles.extend(
2304            self.rendered_frame.cursor_styles
2305                [range.start.cursor_styles_index..range.end.cursor_styles_index]
2306                .iter()
2307                .cloned(),
2308        );
2309        self.next_frame.input_handlers.extend(
2310            self.rendered_frame.input_handlers
2311                [range.start.input_handlers_index..range.end.input_handlers_index]
2312                .iter_mut()
2313                .map(|handler| handler.take()),
2314        );
2315        self.next_frame.mouse_listeners.extend(
2316            self.rendered_frame.mouse_listeners
2317                [range.start.mouse_listeners_index..range.end.mouse_listeners_index]
2318                .iter_mut()
2319                .map(|listener| listener.take()),
2320        );
2321        self.next_frame.accessed_element_states.extend(
2322            self.rendered_frame.accessed_element_states[range.start.accessed_element_states_index
2323                ..range.end.accessed_element_states_index]
2324                .iter()
2325                .map(|(id, type_id)| (id.clone(), *type_id)),
2326        );
2327        self.next_frame.tab_stops.replay(
2328            &self.rendered_frame.tab_stops.insertion_history
2329                [range.start.tab_handle_index..range.end.tab_handle_index],
2330        );
2331
2332        self.text_system
2333            .reuse_layouts(range.start.line_layout_index..range.end.line_layout_index);
2334        self.next_frame.scene.replay(
2335            range.start.scene_index..range.end.scene_index,
2336            &self.rendered_frame.scene,
2337        );
2338    }
2339
2340    /// Push a text style onto the stack, and call a function with that style active.
2341    /// Use [`Window::text_style`] to get the current, combined text style. This method
2342    /// should only be called as part of element drawing.
2343    pub fn with_text_style<F, R>(&mut self, style: Option<TextStyleRefinement>, f: F) -> R
2344    where
2345        F: FnOnce(&mut Self) -> R,
2346    {
2347        self.invalidator.debug_assert_paint_or_prepaint();
2348        if let Some(style) = style {
2349            self.text_style_stack.push(style);
2350            let result = f(self);
2351            self.text_style_stack.pop();
2352            result
2353        } else {
2354            f(self)
2355        }
2356    }
2357
2358    /// Updates the cursor style at the platform level. This method should only be called
2359    /// during the prepaint phase of element drawing.
2360    pub fn set_cursor_style(&mut self, style: CursorStyle, hitbox: &Hitbox) {
2361        self.invalidator.debug_assert_paint();
2362        self.next_frame.cursor_styles.push(CursorStyleRequest {
2363            hitbox_id: Some(hitbox.id),
2364            style,
2365        });
2366    }
2367
2368    /// Updates the cursor style for the entire window at the platform level. A cursor
2369    /// style using this method will have precedence over any cursor style set using
2370    /// `set_cursor_style`. This method should only be called during the prepaint
2371    /// phase of element drawing.
2372    pub fn set_window_cursor_style(&mut self, style: CursorStyle) {
2373        self.invalidator.debug_assert_paint();
2374        self.next_frame.cursor_styles.push(CursorStyleRequest {
2375            hitbox_id: None,
2376            style,
2377        })
2378    }
2379
2380    /// Sets a tooltip to be rendered for the upcoming frame. This method should only be called
2381    /// during the paint phase of element drawing.
2382    pub fn set_tooltip(&mut self, tooltip: AnyTooltip) -> TooltipId {
2383        self.invalidator.debug_assert_prepaint();
2384        let id = TooltipId(post_inc(&mut self.next_tooltip_id.0));
2385        self.next_frame
2386            .tooltip_requests
2387            .push(Some(TooltipRequest { id, tooltip }));
2388        id
2389    }
2390
2391    /// Invoke the given function with the given content mask after intersecting it
2392    /// with the current mask. This method should only be called during element drawing.
2393    pub fn with_content_mask<R>(
2394        &mut self,
2395        mask: Option<ContentMask<Pixels>>,
2396        f: impl FnOnce(&mut Self) -> R,
2397    ) -> R {
2398        self.invalidator.debug_assert_paint_or_prepaint();
2399        if let Some(mask) = mask {
2400            let mask = mask.intersect(&self.content_mask());
2401            self.content_mask_stack.push(mask);
2402            let result = f(self);
2403            self.content_mask_stack.pop();
2404            result
2405        } else {
2406            f(self)
2407        }
2408    }
2409
2410    /// Updates the global element offset relative to the current offset. This is used to implement
2411    /// scrolling. This method should only be called during the prepaint phase of element drawing.
2412    pub fn with_element_offset<R>(
2413        &mut self,
2414        offset: Point<Pixels>,
2415        f: impl FnOnce(&mut Self) -> R,
2416    ) -> R {
2417        self.invalidator.debug_assert_prepaint();
2418
2419        if offset.is_zero() {
2420            return f(self);
2421        };
2422
2423        let abs_offset = self.element_offset() + offset;
2424        self.with_absolute_element_offset(abs_offset, f)
2425    }
2426
2427    /// Updates the global element offset based on the given offset. This is used to implement
2428    /// drag handles and other manual painting of elements. This method should only be called during
2429    /// the prepaint phase of element drawing.
2430    pub fn with_absolute_element_offset<R>(
2431        &mut self,
2432        offset: Point<Pixels>,
2433        f: impl FnOnce(&mut Self) -> R,
2434    ) -> R {
2435        self.invalidator.debug_assert_prepaint();
2436        self.element_offset_stack.push(offset);
2437        let result = f(self);
2438        self.element_offset_stack.pop();
2439        result
2440    }
2441
2442    pub(crate) fn with_element_opacity<R>(
2443        &mut self,
2444        opacity: Option<f32>,
2445        f: impl FnOnce(&mut Self) -> R,
2446    ) -> R {
2447        self.invalidator.debug_assert_paint_or_prepaint();
2448
2449        let Some(opacity) = opacity else {
2450            return f(self);
2451        };
2452
2453        let previous_opacity = self.element_opacity;
2454        self.element_opacity = previous_opacity * opacity;
2455        let result = f(self);
2456        self.element_opacity = previous_opacity;
2457        result
2458    }
2459
2460    /// Perform prepaint on child elements in a "retryable" manner, so that any side effects
2461    /// of prepaints can be discarded before prepainting again. This is used to support autoscroll
2462    /// where we need to prepaint children to detect the autoscroll bounds, then adjust the
2463    /// element offset and prepaint again. See [`crate::List`] for an example. This method should only be
2464    /// called during the prepaint phase of element drawing.
2465    pub fn transact<T, U>(&mut self, f: impl FnOnce(&mut Self) -> Result<T, U>) -> Result<T, U> {
2466        self.invalidator.debug_assert_prepaint();
2467        let index = self.prepaint_index();
2468        let result = f(self);
2469        if result.is_err() {
2470            self.next_frame.hitboxes.truncate(index.hitboxes_index);
2471            self.next_frame
2472                .tooltip_requests
2473                .truncate(index.tooltips_index);
2474            self.next_frame
2475                .deferred_draws
2476                .truncate(index.deferred_draws_index);
2477            self.next_frame
2478                .dispatch_tree
2479                .truncate(index.dispatch_tree_index);
2480            self.next_frame
2481                .accessed_element_states
2482                .truncate(index.accessed_element_states_index);
2483            self.text_system.truncate_layouts(index.line_layout_index);
2484        }
2485        result
2486    }
2487
2488    /// When you call this method during [`Element::prepaint`], containing elements will attempt to
2489    /// scroll to cause the specified bounds to become visible. When they decide to autoscroll, they will call
2490    /// [`Element::prepaint`] again with a new set of bounds. See [`crate::List`] for an example of an element
2491    /// that supports this method being called on the elements it contains. This method should only be
2492    /// called during the prepaint phase of element drawing.
2493    pub fn request_autoscroll(&mut self, bounds: Bounds<Pixels>) {
2494        self.invalidator.debug_assert_prepaint();
2495        self.requested_autoscroll = Some(bounds);
2496    }
2497
2498    /// This method can be called from a containing element such as [`crate::List`] to support the autoscroll behavior
2499    /// described in [`Self::request_autoscroll`].
2500    pub fn take_autoscroll(&mut self) -> Option<Bounds<Pixels>> {
2501        self.invalidator.debug_assert_prepaint();
2502        self.requested_autoscroll.take()
2503    }
2504
2505    /// Asynchronously load an asset, if the asset hasn't finished loading this will return None.
2506    /// Your view will be re-drawn once the asset has finished loading.
2507    ///
2508    /// Note that the multiple calls to this method will only result in one `Asset::load` call at a
2509    /// time.
2510    pub fn use_asset<A: Asset>(&mut self, source: &A::Source, cx: &mut App) -> Option<A::Output> {
2511        let (task, is_first) = cx.fetch_asset::<A>(source);
2512        task.clone().now_or_never().or_else(|| {
2513            if is_first {
2514                let entity_id = self.current_view();
2515                self.spawn(cx, {
2516                    let task = task.clone();
2517                    async move |cx| {
2518                        task.await;
2519
2520                        cx.on_next_frame(move |_, cx| {
2521                            cx.notify(entity_id);
2522                        });
2523                    }
2524                })
2525                .detach();
2526            }
2527
2528            None
2529        })
2530    }
2531
2532    /// Asynchronously load an asset, if the asset hasn't finished loading or doesn't exist this will return None.
2533    /// Your view will not be re-drawn once the asset has finished loading.
2534    ///
2535    /// Note that the multiple calls to this method will only result in one `Asset::load` call at a
2536    /// time.
2537    pub fn get_asset<A: Asset>(&mut self, source: &A::Source, cx: &mut App) -> Option<A::Output> {
2538        let (task, _) = cx.fetch_asset::<A>(source);
2539        task.now_or_never()
2540    }
2541    /// Obtain the current element offset. This method should only be called during the
2542    /// prepaint phase of element drawing.
2543    pub fn element_offset(&self) -> Point<Pixels> {
2544        self.invalidator.debug_assert_prepaint();
2545        self.element_offset_stack
2546            .last()
2547            .copied()
2548            .unwrap_or_default()
2549    }
2550
2551    /// Obtain the current element opacity. This method should only be called during the
2552    /// prepaint phase of element drawing.
2553    #[inline]
2554    pub(crate) fn element_opacity(&self) -> f32 {
2555        self.invalidator.debug_assert_paint_or_prepaint();
2556        self.element_opacity
2557    }
2558
2559    /// Obtain the current content mask. This method should only be called during element drawing.
2560    pub fn content_mask(&self) -> ContentMask<Pixels> {
2561        self.invalidator.debug_assert_paint_or_prepaint();
2562        self.content_mask_stack
2563            .last()
2564            .cloned()
2565            .unwrap_or_else(|| ContentMask {
2566                bounds: Bounds {
2567                    origin: Point::default(),
2568                    size: self.viewport_size,
2569                },
2570            })
2571    }
2572
2573    /// Provide elements in the called function with a new namespace in which their identifiers must be unique.
2574    /// This can be used within a custom element to distinguish multiple sets of child elements.
2575    pub fn with_element_namespace<R>(
2576        &mut self,
2577        element_id: impl Into<ElementId>,
2578        f: impl FnOnce(&mut Self) -> R,
2579    ) -> R {
2580        self.element_id_stack.push(element_id.into());
2581        let result = f(self);
2582        self.element_id_stack.pop();
2583        result
2584    }
2585
2586    /// Use a piece of state that exists as long this element is being rendered in consecutive frames.
2587    pub fn use_keyed_state<S: 'static>(
2588        &mut self,
2589        key: impl Into<ElementId>,
2590        cx: &mut App,
2591        init: impl FnOnce(&mut Self, &mut Context<S>) -> S,
2592    ) -> Entity<S> {
2593        let current_view = self.current_view();
2594        self.with_global_id(key.into(), |global_id, window| {
2595            window.with_element_state(global_id, |state: Option<Entity<S>>, window| {
2596                if let Some(state) = state {
2597                    (state.clone(), state)
2598                } else {
2599                    let new_state = cx.new(|cx| init(window, cx));
2600                    cx.observe(&new_state, move |_, cx| {
2601                        cx.notify(current_view);
2602                    })
2603                    .detach();
2604                    (new_state.clone(), new_state)
2605                }
2606            })
2607        })
2608    }
2609
2610    /// Immediately push an element ID onto the stack. Useful for simplifying IDs in lists
2611    pub fn with_id<R>(&mut self, id: impl Into<ElementId>, f: impl FnOnce(&mut Self) -> R) -> R {
2612        self.with_global_id(id.into(), |_, window| f(window))
2613    }
2614
2615    /// Use a piece of state that exists as long this element is being rendered in consecutive frames, without needing to specify a key
2616    ///
2617    /// NOTE: This method uses the location of the caller to generate an ID for this state.
2618    ///       If this is not sufficient to identify your state (e.g. you're rendering a list item),
2619    ///       you can provide a custom ElementID using the `use_keyed_state` method.
2620    #[track_caller]
2621    pub fn use_state<S: 'static>(
2622        &mut self,
2623        cx: &mut App,
2624        init: impl FnOnce(&mut Self, &mut Context<S>) -> S,
2625    ) -> Entity<S> {
2626        self.use_keyed_state(
2627            ElementId::CodeLocation(*core::panic::Location::caller()),
2628            cx,
2629            init,
2630        )
2631    }
2632
2633    /// Updates or initializes state for an element with the given id that lives across multiple
2634    /// frames. If an element with this ID existed in the rendered frame, its state will be passed
2635    /// to the given closure. The state returned by the closure will be stored so it can be referenced
2636    /// when drawing the next frame. This method should only be called as part of element drawing.
2637    pub fn with_element_state<S, R>(
2638        &mut self,
2639        global_id: &GlobalElementId,
2640        f: impl FnOnce(Option<S>, &mut Self) -> (R, S),
2641    ) -> R
2642    where
2643        S: 'static,
2644    {
2645        self.invalidator.debug_assert_paint_or_prepaint();
2646
2647        let key = (global_id.clone(), TypeId::of::<S>());
2648        self.next_frame.accessed_element_states.push(key.clone());
2649
2650        if let Some(any) = self
2651            .next_frame
2652            .element_states
2653            .remove(&key)
2654            .or_else(|| self.rendered_frame.element_states.remove(&key))
2655        {
2656            let ElementStateBox {
2657                inner,
2658                #[cfg(debug_assertions)]
2659                type_name,
2660            } = any;
2661            // Using the extra inner option to avoid needing to reallocate a new box.
2662            let mut state_box = inner
2663                .downcast::<Option<S>>()
2664                .map_err(|_| {
2665                    #[cfg(debug_assertions)]
2666                    {
2667                        anyhow::anyhow!(
2668                            "invalid element state type for id, requested {:?}, actual: {:?}",
2669                            std::any::type_name::<S>(),
2670                            type_name
2671                        )
2672                    }
2673
2674                    #[cfg(not(debug_assertions))]
2675                    {
2676                        anyhow::anyhow!(
2677                            "invalid element state type for id, requested {:?}",
2678                            std::any::type_name::<S>(),
2679                        )
2680                    }
2681                })
2682                .unwrap();
2683
2684            let state = state_box.take().expect(
2685                "reentrant call to with_element_state for the same state type and element id",
2686            );
2687            let (result, state) = f(Some(state), self);
2688            state_box.replace(state);
2689            self.next_frame.element_states.insert(
2690                key,
2691                ElementStateBox {
2692                    inner: state_box,
2693                    #[cfg(debug_assertions)]
2694                    type_name,
2695                },
2696            );
2697            result
2698        } else {
2699            let (result, state) = f(None, self);
2700            self.next_frame.element_states.insert(
2701                key,
2702                ElementStateBox {
2703                    inner: Box::new(Some(state)),
2704                    #[cfg(debug_assertions)]
2705                    type_name: std::any::type_name::<S>(),
2706                },
2707            );
2708            result
2709        }
2710    }
2711
2712    /// A variant of `with_element_state` that allows the element's id to be optional. This is a convenience
2713    /// method for elements where the element id may or may not be assigned. Prefer using `with_element_state`
2714    /// when the element is guaranteed to have an id.
2715    ///
2716    /// The first option means 'no ID provided'
2717    /// The second option means 'not yet initialized'
2718    pub fn with_optional_element_state<S, R>(
2719        &mut self,
2720        global_id: Option<&GlobalElementId>,
2721        f: impl FnOnce(Option<Option<S>>, &mut Self) -> (R, Option<S>),
2722    ) -> R
2723    where
2724        S: 'static,
2725    {
2726        self.invalidator.debug_assert_paint_or_prepaint();
2727
2728        if let Some(global_id) = global_id {
2729            self.with_element_state(global_id, |state, cx| {
2730                let (result, state) = f(Some(state), cx);
2731                let state =
2732                    state.expect("you must return some state when you pass some element id");
2733                (result, state)
2734            })
2735        } else {
2736            let (result, state) = f(None, self);
2737            debug_assert!(
2738                state.is_none(),
2739                "you must not return an element state when passing None for the global id"
2740            );
2741            result
2742        }
2743    }
2744
2745    /// Executes the given closure within the context of a tab group.
2746    #[inline]
2747    pub fn with_tab_group<R>(&mut self, index: Option<isize>, f: impl FnOnce(&mut Self) -> R) -> R {
2748        if let Some(index) = index {
2749            self.next_frame.tab_stops.begin_group(index);
2750            let result = f(self);
2751            self.next_frame.tab_stops.end_group();
2752            result
2753        } else {
2754            f(self)
2755        }
2756    }
2757
2758    /// Defers the drawing of the given element, scheduling it to be painted on top of the currently-drawn tree
2759    /// at a later time. The `priority` parameter determines the drawing order relative to other deferred elements,
2760    /// with higher values being drawn on top.
2761    ///
2762    /// This method should only be called as part of the prepaint phase of element drawing.
2763    pub fn defer_draw(
2764        &mut self,
2765        element: AnyElement,
2766        absolute_offset: Point<Pixels>,
2767        priority: usize,
2768    ) {
2769        self.invalidator.debug_assert_prepaint();
2770        let parent_node = self.next_frame.dispatch_tree.active_node_id().unwrap();
2771        self.next_frame.deferred_draws.push(DeferredDraw {
2772            current_view: self.current_view(),
2773            parent_node,
2774            element_id_stack: self.element_id_stack.clone(),
2775            text_style_stack: self.text_style_stack.clone(),
2776            priority,
2777            element: Some(element),
2778            absolute_offset,
2779            prepaint_range: PrepaintStateIndex::default()..PrepaintStateIndex::default(),
2780            paint_range: PaintIndex::default()..PaintIndex::default(),
2781        });
2782    }
2783
2784    /// Creates a new painting layer for the specified bounds. A "layer" is a batch
2785    /// of geometry that are non-overlapping and have the same draw order. This is typically used
2786    /// for performance reasons.
2787    ///
2788    /// This method should only be called as part of the paint phase of element drawing.
2789    pub fn paint_layer<R>(&mut self, bounds: Bounds<Pixels>, f: impl FnOnce(&mut Self) -> R) -> R {
2790        self.invalidator.debug_assert_paint();
2791
2792        let scale_factor = self.scale_factor();
2793        let content_mask = self.content_mask();
2794        let clipped_bounds = bounds.intersect(&content_mask.bounds);
2795        if !clipped_bounds.is_empty() {
2796            self.next_frame
2797                .scene
2798                .push_layer(clipped_bounds.scale(scale_factor));
2799        }
2800
2801        let result = f(self);
2802
2803        if !clipped_bounds.is_empty() {
2804            self.next_frame.scene.pop_layer();
2805        }
2806
2807        result
2808    }
2809
2810    /// Paint one or more drop shadows into the scene for the next frame at the current z-index.
2811    ///
2812    /// This method should only be called as part of the paint phase of element drawing.
2813    pub fn paint_shadows(
2814        &mut self,
2815        bounds: Bounds<Pixels>,
2816        corner_radii: Corners<Pixels>,
2817        shadows: &[BoxShadow],
2818    ) {
2819        self.invalidator.debug_assert_paint();
2820
2821        let scale_factor = self.scale_factor();
2822        let content_mask = self.content_mask();
2823        let opacity = self.element_opacity();
2824        for shadow in shadows {
2825            let shadow_bounds = (bounds + shadow.offset).dilate(shadow.spread_radius);
2826            self.next_frame.scene.insert_primitive(Shadow {
2827                order: 0,
2828                blur_radius: shadow.blur_radius.scale(scale_factor),
2829                bounds: shadow_bounds.scale(scale_factor),
2830                content_mask: content_mask.scale(scale_factor),
2831                corner_radii: corner_radii.scale(scale_factor),
2832                color: shadow.color.opacity(opacity),
2833            });
2834        }
2835    }
2836
2837    /// Paint one or more quads into the scene for the next frame at the current stacking context.
2838    /// Quads are colored rectangular regions with an optional background, border, and corner radius.
2839    /// see [`fill`], [`outline`], and [`quad`] to construct this type.
2840    ///
2841    /// This method should only be called as part of the paint phase of element drawing.
2842    ///
2843    /// Note that the `quad.corner_radii` are allowed to exceed the bounds, creating sharp corners
2844    /// where the circular arcs meet. This will not display well when combined with dashed borders.
2845    /// Use `Corners::clamp_radii_for_quad_size` if the radii should fit within the bounds.
2846    pub fn paint_quad(&mut self, quad: PaintQuad) {
2847        self.invalidator.debug_assert_paint();
2848
2849        let scale_factor = self.scale_factor();
2850        let content_mask = self.content_mask();
2851        let opacity = self.element_opacity();
2852        self.next_frame.scene.insert_primitive(Quad {
2853            order: 0,
2854            bounds: quad.bounds.scale(scale_factor),
2855            content_mask: content_mask.scale(scale_factor),
2856            background: quad.background.opacity(opacity),
2857            border_color: quad.border_color.opacity(opacity),
2858            corner_radii: quad.corner_radii.scale(scale_factor),
2859            border_widths: quad.border_widths.scale(scale_factor),
2860            border_style: quad.border_style,
2861        });
2862    }
2863
2864    /// Paint the given `Path` into the scene for the next frame at the current z-index.
2865    ///
2866    /// This method should only be called as part of the paint phase of element drawing.
2867    pub fn paint_path(&mut self, mut path: Path<Pixels>, color: impl Into<Background>) {
2868        self.invalidator.debug_assert_paint();
2869
2870        let scale_factor = self.scale_factor();
2871        let content_mask = self.content_mask();
2872        let opacity = self.element_opacity();
2873        path.content_mask = content_mask;
2874        let color: Background = color.into();
2875        path.color = color.opacity(opacity);
2876        self.next_frame
2877            .scene
2878            .insert_primitive(path.scale(scale_factor));
2879    }
2880
2881    /// Paint an underline into the scene for the next frame at the current z-index.
2882    ///
2883    /// This method should only be called as part of the paint phase of element drawing.
2884    pub fn paint_underline(
2885        &mut self,
2886        origin: Point<Pixels>,
2887        width: Pixels,
2888        style: &UnderlineStyle,
2889    ) {
2890        self.invalidator.debug_assert_paint();
2891
2892        let scale_factor = self.scale_factor();
2893        let height = if style.wavy {
2894            style.thickness * 3.
2895        } else {
2896            style.thickness
2897        };
2898        let bounds = Bounds {
2899            origin,
2900            size: size(width, height),
2901        };
2902        let content_mask = self.content_mask();
2903        let element_opacity = self.element_opacity();
2904
2905        self.next_frame.scene.insert_primitive(Underline {
2906            order: 0,
2907            pad: 0,
2908            bounds: bounds.scale(scale_factor),
2909            content_mask: content_mask.scale(scale_factor),
2910            color: style.color.unwrap_or_default().opacity(element_opacity),
2911            thickness: style.thickness.scale(scale_factor),
2912            wavy: if style.wavy { 1 } else { 0 },
2913        });
2914    }
2915
2916    /// Paint a strikethrough into the scene for the next frame at the current z-index.
2917    ///
2918    /// This method should only be called as part of the paint phase of element drawing.
2919    pub fn paint_strikethrough(
2920        &mut self,
2921        origin: Point<Pixels>,
2922        width: Pixels,
2923        style: &StrikethroughStyle,
2924    ) {
2925        self.invalidator.debug_assert_paint();
2926
2927        let scale_factor = self.scale_factor();
2928        let height = style.thickness;
2929        let bounds = Bounds {
2930            origin,
2931            size: size(width, height),
2932        };
2933        let content_mask = self.content_mask();
2934        let opacity = self.element_opacity();
2935
2936        self.next_frame.scene.insert_primitive(Underline {
2937            order: 0,
2938            pad: 0,
2939            bounds: bounds.scale(scale_factor),
2940            content_mask: content_mask.scale(scale_factor),
2941            thickness: style.thickness.scale(scale_factor),
2942            color: style.color.unwrap_or_default().opacity(opacity),
2943            wavy: 0,
2944        });
2945    }
2946
2947    /// Paints a monochrome (non-emoji) glyph into the scene for the next frame at the current z-index.
2948    ///
2949    /// The y component of the origin is the baseline of the glyph.
2950    /// You should generally prefer to use the [`ShapedLine::paint`](crate::ShapedLine::paint) or
2951    /// [`WrappedLine::paint`](crate::WrappedLine::paint) methods in the [`TextSystem`](crate::TextSystem).
2952    /// This method is only useful if you need to paint a single glyph that has already been shaped.
2953    ///
2954    /// This method should only be called as part of the paint phase of element drawing.
2955    pub fn paint_glyph(
2956        &mut self,
2957        origin: Point<Pixels>,
2958        font_id: FontId,
2959        glyph_id: GlyphId,
2960        font_size: Pixels,
2961        color: Hsla,
2962    ) -> Result<()> {
2963        self.invalidator.debug_assert_paint();
2964
2965        let element_opacity = self.element_opacity();
2966        let scale_factor = self.scale_factor();
2967        let glyph_origin = origin.scale(scale_factor);
2968
2969        let subpixel_variant = Point {
2970            x: (glyph_origin.x.0.fract() * SUBPIXEL_VARIANTS_X as f32).floor() as u8,
2971            y: (glyph_origin.y.0.fract() * SUBPIXEL_VARIANTS_Y as f32).floor() as u8,
2972        };
2973        let params = RenderGlyphParams {
2974            font_id,
2975            glyph_id,
2976            font_size,
2977            subpixel_variant,
2978            scale_factor,
2979            is_emoji: false,
2980        };
2981
2982        let raster_bounds = self.text_system().raster_bounds(&params)?;
2983        if !raster_bounds.is_zero() {
2984            let tile = self
2985                .sprite_atlas
2986                .get_or_insert_with(&params.clone().into(), &mut || {
2987                    let (size, bytes) = self.text_system().rasterize_glyph(&params)?;
2988                    Ok(Some((size, Cow::Owned(bytes))))
2989                })?
2990                .expect("Callback above only errors or returns Some");
2991            let bounds = Bounds {
2992                origin: glyph_origin.map(|px| px.floor()) + raster_bounds.origin.map(Into::into),
2993                size: tile.bounds.size.map(Into::into),
2994            };
2995            let content_mask = self.content_mask().scale(scale_factor);
2996            self.next_frame.scene.insert_primitive(MonochromeSprite {
2997                order: 0,
2998                pad: 0,
2999                bounds,
3000                content_mask,
3001                color: color.opacity(element_opacity),
3002                tile,
3003                transformation: TransformationMatrix::unit(),
3004            });
3005        }
3006        Ok(())
3007    }
3008
3009    /// Paints an emoji glyph into the scene for the next frame at the current z-index.
3010    ///
3011    /// The y component of the origin is the baseline of the glyph.
3012    /// You should generally prefer to use the [`ShapedLine::paint`](crate::ShapedLine::paint) or
3013    /// [`WrappedLine::paint`](crate::WrappedLine::paint) methods in the [`TextSystem`](crate::TextSystem).
3014    /// This method is only useful if you need to paint a single emoji that has already been shaped.
3015    ///
3016    /// This method should only be called as part of the paint phase of element drawing.
3017    pub fn paint_emoji(
3018        &mut self,
3019        origin: Point<Pixels>,
3020        font_id: FontId,
3021        glyph_id: GlyphId,
3022        font_size: Pixels,
3023    ) -> Result<()> {
3024        self.invalidator.debug_assert_paint();
3025
3026        let scale_factor = self.scale_factor();
3027        let glyph_origin = origin.scale(scale_factor);
3028        let params = RenderGlyphParams {
3029            font_id,
3030            glyph_id,
3031            font_size,
3032            // We don't render emojis with subpixel variants.
3033            subpixel_variant: Default::default(),
3034            scale_factor,
3035            is_emoji: true,
3036        };
3037
3038        let raster_bounds = self.text_system().raster_bounds(&params)?;
3039        if !raster_bounds.is_zero() {
3040            let tile = self
3041                .sprite_atlas
3042                .get_or_insert_with(&params.clone().into(), &mut || {
3043                    let (size, bytes) = self.text_system().rasterize_glyph(&params)?;
3044                    Ok(Some((size, Cow::Owned(bytes))))
3045                })?
3046                .expect("Callback above only errors or returns Some");
3047
3048            let bounds = Bounds {
3049                origin: glyph_origin.map(|px| px.floor()) + raster_bounds.origin.map(Into::into),
3050                size: tile.bounds.size.map(Into::into),
3051            };
3052            let content_mask = self.content_mask().scale(scale_factor);
3053            let opacity = self.element_opacity();
3054
3055            self.next_frame.scene.insert_primitive(PolychromeSprite {
3056                order: 0,
3057                pad: 0,
3058                grayscale: false,
3059                bounds,
3060                corner_radii: Default::default(),
3061                content_mask,
3062                tile,
3063                opacity,
3064            });
3065        }
3066        Ok(())
3067    }
3068
3069    /// Paint a monochrome SVG into the scene for the next frame at the current stacking context.
3070    ///
3071    /// This method should only be called as part of the paint phase of element drawing.
3072    pub fn paint_svg(
3073        &mut self,
3074        bounds: Bounds<Pixels>,
3075        path: SharedString,
3076        transformation: TransformationMatrix,
3077        color: Hsla,
3078        cx: &App,
3079    ) -> Result<()> {
3080        self.invalidator.debug_assert_paint();
3081
3082        let element_opacity = self.element_opacity();
3083        let scale_factor = self.scale_factor();
3084
3085        let bounds = bounds.scale(scale_factor);
3086        let params = RenderSvgParams {
3087            path,
3088            size: bounds.size.map(|pixels| {
3089                DevicePixels::from((pixels.0 * SMOOTH_SVG_SCALE_FACTOR).ceil() as i32)
3090            }),
3091        };
3092
3093        let Some(tile) =
3094            self.sprite_atlas
3095                .get_or_insert_with(&params.clone().into(), &mut || {
3096                    let Some((size, bytes)) = cx.svg_renderer.render(&params)? else {
3097                        return Ok(None);
3098                    };
3099                    Ok(Some((size, Cow::Owned(bytes))))
3100                })?
3101        else {
3102            return Ok(());
3103        };
3104        let content_mask = self.content_mask().scale(scale_factor);
3105        let svg_bounds = Bounds {
3106            origin: bounds.center()
3107                - Point::new(
3108                    ScaledPixels(tile.bounds.size.width.0 as f32 / SMOOTH_SVG_SCALE_FACTOR / 2.),
3109                    ScaledPixels(tile.bounds.size.height.0 as f32 / SMOOTH_SVG_SCALE_FACTOR / 2.),
3110                ),
3111            size: tile
3112                .bounds
3113                .size
3114                .map(|value| ScaledPixels(value.0 as f32 / SMOOTH_SVG_SCALE_FACTOR)),
3115        };
3116
3117        self.next_frame.scene.insert_primitive(MonochromeSprite {
3118            order: 0,
3119            pad: 0,
3120            bounds: svg_bounds
3121                .map_origin(|origin| origin.round())
3122                .map_size(|size| size.ceil()),
3123            content_mask,
3124            color: color.opacity(element_opacity),
3125            tile,
3126            transformation,
3127        });
3128
3129        Ok(())
3130    }
3131
3132    /// Paint an image into the scene for the next frame at the current z-index.
3133    /// This method will panic if the frame_index is not valid
3134    ///
3135    /// This method should only be called as part of the paint phase of element drawing.
3136    pub fn paint_image(
3137        &mut self,
3138        bounds: Bounds<Pixels>,
3139        corner_radii: Corners<Pixels>,
3140        data: Arc<RenderImage>,
3141        frame_index: usize,
3142        grayscale: bool,
3143    ) -> Result<()> {
3144        self.invalidator.debug_assert_paint();
3145
3146        let scale_factor = self.scale_factor();
3147        let bounds = bounds.scale(scale_factor);
3148        let params = RenderImageParams {
3149            image_id: data.id,
3150            frame_index,
3151        };
3152
3153        let tile = self
3154            .sprite_atlas
3155            .get_or_insert_with(&params.into(), &mut || {
3156                Ok(Some((
3157                    data.size(frame_index),
3158                    Cow::Borrowed(
3159                        data.as_bytes(frame_index)
3160                            .expect("It's the caller's job to pass a valid frame index"),
3161                    ),
3162                )))
3163            })?
3164            .expect("Callback above only returns Some");
3165        let content_mask = self.content_mask().scale(scale_factor);
3166        let corner_radii = corner_radii.scale(scale_factor);
3167        let opacity = self.element_opacity();
3168
3169        self.next_frame.scene.insert_primitive(PolychromeSprite {
3170            order: 0,
3171            pad: 0,
3172            grayscale,
3173            bounds: bounds
3174                .map_origin(|origin| origin.floor())
3175                .map_size(|size| size.ceil()),
3176            content_mask,
3177            corner_radii,
3178            tile,
3179            opacity,
3180        });
3181        Ok(())
3182    }
3183
3184    /// Paint a surface into the scene for the next frame at the current z-index.
3185    ///
3186    /// This method should only be called as part of the paint phase of element drawing.
3187    #[cfg(target_os = "macos")]
3188    pub fn paint_surface(&mut self, bounds: Bounds<Pixels>, image_buffer: CVPixelBuffer) {
3189        use crate::PaintSurface;
3190
3191        self.invalidator.debug_assert_paint();
3192
3193        let scale_factor = self.scale_factor();
3194        let bounds = bounds.scale(scale_factor);
3195        let content_mask = self.content_mask().scale(scale_factor);
3196        self.next_frame.scene.insert_primitive(PaintSurface {
3197            order: 0,
3198            bounds,
3199            content_mask,
3200            image_buffer,
3201        });
3202    }
3203
3204    /// Removes an image from the sprite atlas.
3205    pub fn drop_image(&mut self, data: Arc<RenderImage>) -> Result<()> {
3206        for frame_index in 0..data.frame_count() {
3207            let params = RenderImageParams {
3208                image_id: data.id,
3209                frame_index,
3210            };
3211
3212            self.sprite_atlas.remove(&params.clone().into());
3213        }
3214
3215        Ok(())
3216    }
3217
3218    /// Add a node to the layout tree for the current frame. Takes the `Style` of the element for which
3219    /// layout is being requested, along with the layout ids of any children. This method is called during
3220    /// calls to the [`Element::request_layout`] trait method and enables any element to participate in layout.
3221    ///
3222    /// This method should only be called as part of the request_layout or prepaint phase of element drawing.
3223    #[must_use]
3224    pub fn request_layout(
3225        &mut self,
3226        style: Style,
3227        children: impl IntoIterator<Item = LayoutId>,
3228        cx: &mut App,
3229    ) -> LayoutId {
3230        self.invalidator.debug_assert_prepaint();
3231
3232        cx.layout_id_buffer.clear();
3233        cx.layout_id_buffer.extend(children);
3234        let rem_size = self.rem_size();
3235        let scale_factor = self.scale_factor();
3236
3237        self.layout_engine.as_mut().unwrap().request_layout(
3238            style,
3239            rem_size,
3240            scale_factor,
3241            &cx.layout_id_buffer,
3242        )
3243    }
3244
3245    /// Add a node to the layout tree for the current frame. Instead of taking a `Style` and children,
3246    /// this variant takes a function that is invoked during layout so you can use arbitrary logic to
3247    /// determine the element's size. One place this is used internally is when measuring text.
3248    ///
3249    /// The given closure is invoked at layout time with the known dimensions and available space and
3250    /// returns a `Size`.
3251    ///
3252    /// This method should only be called as part of the request_layout or prepaint phase of element drawing.
3253    pub fn request_measured_layout<
3254        F: FnMut(Size<Option<Pixels>>, Size<AvailableSpace>, &mut Window, &mut App) -> Size<Pixels>
3255            + 'static,
3256    >(
3257        &mut self,
3258        style: Style,
3259        measure: F,
3260    ) -> LayoutId {
3261        self.invalidator.debug_assert_prepaint();
3262
3263        let rem_size = self.rem_size();
3264        let scale_factor = self.scale_factor();
3265        self.layout_engine
3266            .as_mut()
3267            .unwrap()
3268            .request_measured_layout(style, rem_size, scale_factor, measure)
3269    }
3270
3271    /// Compute the layout for the given id within the given available space.
3272    /// This method is called for its side effect, typically by the framework prior to painting.
3273    /// After calling it, you can request the bounds of the given layout node id or any descendant.
3274    ///
3275    /// This method should only be called as part of the prepaint phase of element drawing.
3276    pub fn compute_layout(
3277        &mut self,
3278        layout_id: LayoutId,
3279        available_space: Size<AvailableSpace>,
3280        cx: &mut App,
3281    ) {
3282        self.invalidator.debug_assert_prepaint();
3283
3284        let mut layout_engine = self.layout_engine.take().unwrap();
3285        layout_engine.compute_layout(layout_id, available_space, self, cx);
3286        self.layout_engine = Some(layout_engine);
3287    }
3288
3289    /// Obtain the bounds computed for the given LayoutId relative to the window. This method will usually be invoked by
3290    /// GPUI itself automatically in order to pass your element its `Bounds` automatically.
3291    ///
3292    /// This method should only be called as part of element drawing.
3293    pub fn layout_bounds(&mut self, layout_id: LayoutId) -> Bounds<Pixels> {
3294        self.invalidator.debug_assert_prepaint();
3295
3296        let scale_factor = self.scale_factor();
3297        let mut bounds = self
3298            .layout_engine
3299            .as_mut()
3300            .unwrap()
3301            .layout_bounds(layout_id, scale_factor)
3302            .map(Into::into);
3303        bounds.origin += self.element_offset();
3304        bounds
3305    }
3306
3307    /// This method should be called during `prepaint`. You can use
3308    /// the returned [Hitbox] during `paint` or in an event handler
3309    /// to determine whether the inserted hitbox was the topmost.
3310    ///
3311    /// This method should only be called as part of the prepaint phase of element drawing.
3312    pub fn insert_hitbox(&mut self, bounds: Bounds<Pixels>, behavior: HitboxBehavior) -> Hitbox {
3313        self.invalidator.debug_assert_prepaint();
3314
3315        let content_mask = self.content_mask();
3316        let mut id = self.next_hitbox_id;
3317        self.next_hitbox_id = self.next_hitbox_id.next();
3318        let hitbox = Hitbox {
3319            id,
3320            bounds,
3321            content_mask,
3322            behavior,
3323        };
3324        self.next_frame.hitboxes.push(hitbox.clone());
3325        hitbox
3326    }
3327
3328    /// Set a hitbox which will act as a control area of the platform window.
3329    ///
3330    /// This method should only be called as part of the paint phase of element drawing.
3331    pub fn insert_window_control_hitbox(&mut self, area: WindowControlArea, hitbox: Hitbox) {
3332        self.invalidator.debug_assert_paint();
3333        self.next_frame.window_control_hitboxes.push((area, hitbox));
3334    }
3335
3336    /// Sets the key context for the current element. This context will be used to translate
3337    /// keybindings into actions.
3338    ///
3339    /// This method should only be called as part of the paint phase of element drawing.
3340    pub fn set_key_context(&mut self, context: KeyContext) {
3341        self.invalidator.debug_assert_paint();
3342        self.next_frame.dispatch_tree.set_key_context(context);
3343    }
3344
3345    /// Sets the focus handle for the current element. This handle will be used to manage focus state
3346    /// and keyboard event dispatch for the element.
3347    ///
3348    /// This method should only be called as part of the prepaint phase of element drawing.
3349    pub fn set_focus_handle(&mut self, focus_handle: &FocusHandle, _: &App) {
3350        self.invalidator.debug_assert_prepaint();
3351        if focus_handle.is_focused(self) {
3352            self.next_frame.focus = Some(focus_handle.id);
3353        }
3354        self.next_frame.dispatch_tree.set_focus_id(focus_handle.id);
3355    }
3356
3357    /// Sets the view id for the current element, which will be used to manage view caching.
3358    ///
3359    /// This method should only be called as part of element prepaint. We plan on removing this
3360    /// method eventually when we solve some issues that require us to construct editor elements
3361    /// directly instead of always using editors via views.
3362    pub fn set_view_id(&mut self, view_id: EntityId) {
3363        self.invalidator.debug_assert_prepaint();
3364        self.next_frame.dispatch_tree.set_view_id(view_id);
3365    }
3366
3367    /// Get the entity ID for the currently rendering view
3368    pub fn current_view(&self) -> EntityId {
3369        self.invalidator.debug_assert_paint_or_prepaint();
3370        self.rendered_entity_stack.last().copied().unwrap()
3371    }
3372
3373    pub(crate) fn with_rendered_view<R>(
3374        &mut self,
3375        id: EntityId,
3376        f: impl FnOnce(&mut Self) -> R,
3377    ) -> R {
3378        self.rendered_entity_stack.push(id);
3379        let result = f(self);
3380        self.rendered_entity_stack.pop();
3381        result
3382    }
3383
3384    /// Executes the provided function with the specified image cache.
3385    pub fn with_image_cache<F, R>(&mut self, image_cache: Option<AnyImageCache>, f: F) -> R
3386    where
3387        F: FnOnce(&mut Self) -> R,
3388    {
3389        if let Some(image_cache) = image_cache {
3390            self.image_cache_stack.push(image_cache);
3391            let result = f(self);
3392            self.image_cache_stack.pop();
3393            result
3394        } else {
3395            f(self)
3396        }
3397    }
3398
3399    /// Sets an input handler, such as [`ElementInputHandler`][element_input_handler], which interfaces with the
3400    /// platform to receive textual input with proper integration with concerns such
3401    /// as IME interactions. This handler will be active for the upcoming frame until the following frame is
3402    /// rendered.
3403    ///
3404    /// This method should only be called as part of the paint phase of element drawing.
3405    ///
3406    /// [element_input_handler]: crate::ElementInputHandler
3407    pub fn handle_input(
3408        &mut self,
3409        focus_handle: &FocusHandle,
3410        input_handler: impl InputHandler,
3411        cx: &App,
3412    ) {
3413        self.invalidator.debug_assert_paint();
3414
3415        if focus_handle.is_focused(self) {
3416            let cx = self.to_async(cx);
3417            self.next_frame
3418                .input_handlers
3419                .push(Some(PlatformInputHandler::new(cx, Box::new(input_handler))));
3420        }
3421    }
3422
3423    /// Register a mouse event listener on the window for the next frame. The type of event
3424    /// is determined by the first parameter of the given listener. When the next frame is rendered
3425    /// the listener will be cleared.
3426    ///
3427    /// This method should only be called as part of the paint phase of element drawing.
3428    pub fn on_mouse_event<Event: MouseEvent>(
3429        &mut self,
3430        mut handler: impl FnMut(&Event, DispatchPhase, &mut Window, &mut App) + 'static,
3431    ) {
3432        self.invalidator.debug_assert_paint();
3433
3434        self.next_frame.mouse_listeners.push(Some(Box::new(
3435            move |event: &dyn Any, phase: DispatchPhase, window: &mut Window, cx: &mut App| {
3436                if let Some(event) = event.downcast_ref() {
3437                    handler(event, phase, window, cx)
3438                }
3439            },
3440        )));
3441    }
3442
3443    /// Register a key event listener on the window for the next frame. The type of event
3444    /// is determined by the first parameter of the given listener. When the next frame is rendered
3445    /// the listener will be cleared.
3446    ///
3447    /// This is a fairly low-level method, so prefer using event handlers on elements unless you have
3448    /// a specific need to register a global listener.
3449    ///
3450    /// This method should only be called as part of the paint phase of element drawing.
3451    pub fn on_key_event<Event: KeyEvent>(
3452        &mut self,
3453        listener: impl Fn(&Event, DispatchPhase, &mut Window, &mut App) + 'static,
3454    ) {
3455        self.invalidator.debug_assert_paint();
3456
3457        self.next_frame.dispatch_tree.on_key_event(Rc::new(
3458            move |event: &dyn Any, phase, window: &mut Window, cx: &mut App| {
3459                if let Some(event) = event.downcast_ref::<Event>() {
3460                    listener(event, phase, window, cx)
3461                }
3462            },
3463        ));
3464    }
3465
3466    /// Register a modifiers changed event listener on the window for the next frame.
3467    ///
3468    /// This is a fairly low-level method, so prefer using event handlers on elements unless you have
3469    /// a specific need to register a global listener.
3470    ///
3471    /// This method should only be called as part of the paint phase of element drawing.
3472    pub fn on_modifiers_changed(
3473        &mut self,
3474        listener: impl Fn(&ModifiersChangedEvent, &mut Window, &mut App) + 'static,
3475    ) {
3476        self.invalidator.debug_assert_paint();
3477
3478        self.next_frame.dispatch_tree.on_modifiers_changed(Rc::new(
3479            move |event: &ModifiersChangedEvent, window: &mut Window, cx: &mut App| {
3480                listener(event, window, cx)
3481            },
3482        ));
3483    }
3484
3485    /// Register a listener to be called when the given focus handle or one of its descendants receives focus.
3486    /// This does not fire if the given focus handle - or one of its descendants - was previously focused.
3487    /// Returns a subscription and persists until the subscription is dropped.
3488    pub fn on_focus_in(
3489        &mut self,
3490        handle: &FocusHandle,
3491        cx: &mut App,
3492        mut listener: impl FnMut(&mut Window, &mut App) + 'static,
3493    ) -> Subscription {
3494        let focus_id = handle.id;
3495        let (subscription, activate) =
3496            self.new_focus_listener(Box::new(move |event, window, cx| {
3497                if event.is_focus_in(focus_id) {
3498                    listener(window, cx);
3499                }
3500                true
3501            }));
3502        cx.defer(move |_| activate());
3503        subscription
3504    }
3505
3506    /// Register a listener to be called when the given focus handle or one of its descendants loses focus.
3507    /// Returns a subscription and persists until the subscription is dropped.
3508    pub fn on_focus_out(
3509        &mut self,
3510        handle: &FocusHandle,
3511        cx: &mut App,
3512        mut listener: impl FnMut(FocusOutEvent, &mut Window, &mut App) + 'static,
3513    ) -> Subscription {
3514        let focus_id = handle.id;
3515        let (subscription, activate) =
3516            self.new_focus_listener(Box::new(move |event, window, cx| {
3517                if let Some(blurred_id) = event.previous_focus_path.last().copied()
3518                    && event.is_focus_out(focus_id)
3519                {
3520                    let event = FocusOutEvent {
3521                        blurred: WeakFocusHandle {
3522                            id: blurred_id,
3523                            handles: Arc::downgrade(&cx.focus_handles),
3524                        },
3525                    };
3526                    listener(event, window, cx)
3527                }
3528                true
3529            }));
3530        cx.defer(move |_| activate());
3531        subscription
3532    }
3533
3534    fn reset_cursor_style(&self, cx: &mut App) {
3535        // Set the cursor only if we're the active window.
3536        if self.is_window_hovered() {
3537            let style = self
3538                .rendered_frame
3539                .cursor_style(self)
3540                .unwrap_or(CursorStyle::Arrow);
3541            cx.platform.set_cursor_style(style);
3542        }
3543    }
3544
3545    /// Dispatch a given keystroke as though the user had typed it.
3546    /// You can create a keystroke with Keystroke::parse("").
3547    pub fn dispatch_keystroke(&mut self, keystroke: Keystroke, cx: &mut App) -> bool {
3548        let keystroke = keystroke.with_simulated_ime();
3549        let result = self.dispatch_event(
3550            PlatformInput::KeyDown(KeyDownEvent {
3551                keystroke: keystroke.clone(),
3552                is_held: false,
3553            }),
3554            cx,
3555        );
3556        if !result.propagate {
3557            return true;
3558        }
3559
3560        if let Some(input) = keystroke.key_char
3561            && let Some(mut input_handler) = self.platform_window.take_input_handler()
3562        {
3563            input_handler.dispatch_input(&input, self, cx);
3564            self.platform_window.set_input_handler(input_handler);
3565            return true;
3566        }
3567
3568        false
3569    }
3570
3571    /// Return a key binding string for an action, to display in the UI. Uses the highest precedence
3572    /// binding for the action (last binding added to the keymap).
3573    pub fn keystroke_text_for(&self, action: &dyn Action) -> String {
3574        self.highest_precedence_binding_for_action(action)
3575            .map(|binding| {
3576                binding
3577                    .keystrokes()
3578                    .iter()
3579                    .map(ToString::to_string)
3580                    .collect::<Vec<_>>()
3581                    .join(" ")
3582            })
3583            .unwrap_or_else(|| action.name().to_string())
3584    }
3585
3586    /// Dispatch a mouse or keyboard event on the window.
3587    #[profiling::function]
3588    pub fn dispatch_event(&mut self, event: PlatformInput, cx: &mut App) -> DispatchEventResult {
3589        self.last_input_timestamp.set(Instant::now());
3590
3591        // Track whether this input was keyboard-based for focus-visible styling
3592        self.last_input_was_keyboard = matches!(
3593            event,
3594            PlatformInput::KeyDown(_)
3595                | PlatformInput::KeyUp(_)
3596                | PlatformInput::ModifiersChanged(_)
3597        );
3598
3599        // Handlers may set this to false by calling `stop_propagation`.
3600        cx.propagate_event = true;
3601        // Handlers may set this to true by calling `prevent_default`.
3602        self.default_prevented = false;
3603
3604        let event = match event {
3605            // Track the mouse position with our own state, since accessing the platform
3606            // API for the mouse position can only occur on the main thread.
3607            PlatformInput::MouseMove(mouse_move) => {
3608                self.mouse_position = mouse_move.position;
3609                self.modifiers = mouse_move.modifiers;
3610                PlatformInput::MouseMove(mouse_move)
3611            }
3612            PlatformInput::MouseDown(mouse_down) => {
3613                self.mouse_position = mouse_down.position;
3614                self.modifiers = mouse_down.modifiers;
3615                PlatformInput::MouseDown(mouse_down)
3616            }
3617            PlatformInput::MouseUp(mouse_up) => {
3618                self.mouse_position = mouse_up.position;
3619                self.modifiers = mouse_up.modifiers;
3620                PlatformInput::MouseUp(mouse_up)
3621            }
3622            PlatformInput::MouseExited(mouse_exited) => {
3623                self.modifiers = mouse_exited.modifiers;
3624                PlatformInput::MouseExited(mouse_exited)
3625            }
3626            PlatformInput::ModifiersChanged(modifiers_changed) => {
3627                self.modifiers = modifiers_changed.modifiers;
3628                self.capslock = modifiers_changed.capslock;
3629                PlatformInput::ModifiersChanged(modifiers_changed)
3630            }
3631            PlatformInput::ScrollWheel(scroll_wheel) => {
3632                self.mouse_position = scroll_wheel.position;
3633                self.modifiers = scroll_wheel.modifiers;
3634                PlatformInput::ScrollWheel(scroll_wheel)
3635            }
3636            // Translate dragging and dropping of external files from the operating system
3637            // to internal drag and drop events.
3638            PlatformInput::FileDrop(file_drop) => match file_drop {
3639                FileDropEvent::Entered { position, paths } => {
3640                    self.mouse_position = position;
3641                    if cx.active_drag.is_none() {
3642                        cx.active_drag = Some(AnyDrag {
3643                            value: Arc::new(paths.clone()),
3644                            view: cx.new(|_| paths).into(),
3645                            cursor_offset: position,
3646                            cursor_style: None,
3647                        });
3648                    }
3649                    PlatformInput::MouseMove(MouseMoveEvent {
3650                        position,
3651                        pressed_button: Some(MouseButton::Left),
3652                        modifiers: Modifiers::default(),
3653                    })
3654                }
3655                FileDropEvent::Pending { position } => {
3656                    self.mouse_position = position;
3657                    PlatformInput::MouseMove(MouseMoveEvent {
3658                        position,
3659                        pressed_button: Some(MouseButton::Left),
3660                        modifiers: Modifiers::default(),
3661                    })
3662                }
3663                FileDropEvent::Submit { position } => {
3664                    cx.activate(true);
3665                    self.mouse_position = position;
3666                    PlatformInput::MouseUp(MouseUpEvent {
3667                        button: MouseButton::Left,
3668                        position,
3669                        modifiers: Modifiers::default(),
3670                        click_count: 1,
3671                    })
3672                }
3673                FileDropEvent::Exited => {
3674                    cx.active_drag.take();
3675                    PlatformInput::FileDrop(FileDropEvent::Exited)
3676                }
3677            },
3678            PlatformInput::KeyDown(_) | PlatformInput::KeyUp(_) => event,
3679        };
3680
3681        if let Some(any_mouse_event) = event.mouse_event() {
3682            self.dispatch_mouse_event(any_mouse_event, cx);
3683        } else if let Some(any_key_event) = event.keyboard_event() {
3684            self.dispatch_key_event(any_key_event, cx);
3685        }
3686
3687        DispatchEventResult {
3688            propagate: cx.propagate_event,
3689            default_prevented: self.default_prevented,
3690        }
3691    }
3692
3693    fn dispatch_mouse_event(&mut self, event: &dyn Any, cx: &mut App) {
3694        let hit_test = self.rendered_frame.hit_test(self.mouse_position());
3695        if hit_test != self.mouse_hit_test {
3696            self.mouse_hit_test = hit_test;
3697            self.reset_cursor_style(cx);
3698        }
3699
3700        #[cfg(any(feature = "inspector", debug_assertions))]
3701        if self.is_inspector_picking(cx) {
3702            self.handle_inspector_mouse_event(event, cx);
3703            // When inspector is picking, all other mouse handling is skipped.
3704            return;
3705        }
3706
3707        let mut mouse_listeners = mem::take(&mut self.rendered_frame.mouse_listeners);
3708
3709        // Capture phase, events bubble from back to front. Handlers for this phase are used for
3710        // special purposes, such as detecting events outside of a given Bounds.
3711        for listener in &mut mouse_listeners {
3712            let listener = listener.as_mut().unwrap();
3713            listener(event, DispatchPhase::Capture, self, cx);
3714            if !cx.propagate_event {
3715                break;
3716            }
3717        }
3718
3719        // Bubble phase, where most normal handlers do their work.
3720        if cx.propagate_event {
3721            for listener in mouse_listeners.iter_mut().rev() {
3722                let listener = listener.as_mut().unwrap();
3723                listener(event, DispatchPhase::Bubble, self, cx);
3724                if !cx.propagate_event {
3725                    break;
3726                }
3727            }
3728        }
3729
3730        self.rendered_frame.mouse_listeners = mouse_listeners;
3731
3732        if cx.has_active_drag() {
3733            if event.is::<MouseMoveEvent>() {
3734                // If this was a mouse move event, redraw the window so that the
3735                // active drag can follow the mouse cursor.
3736                self.refresh();
3737            } else if event.is::<MouseUpEvent>() {
3738                // If this was a mouse up event, cancel the active drag and redraw
3739                // the window.
3740                cx.active_drag = None;
3741                self.refresh();
3742            }
3743        }
3744    }
3745
3746    fn dispatch_key_event(&mut self, event: &dyn Any, cx: &mut App) {
3747        if self.invalidator.is_dirty() {
3748            self.draw(cx).clear();
3749        }
3750
3751        let node_id = self.focus_node_id_in_rendered_frame(self.focus);
3752        let dispatch_path = self.rendered_frame.dispatch_tree.dispatch_path(node_id);
3753
3754        let mut keystroke: Option<Keystroke> = None;
3755
3756        if let Some(event) = event.downcast_ref::<ModifiersChangedEvent>() {
3757            if event.modifiers.number_of_modifiers() == 0
3758                && self.pending_modifier.modifiers.number_of_modifiers() == 1
3759                && !self.pending_modifier.saw_keystroke
3760            {
3761                let key = match self.pending_modifier.modifiers {
3762                    modifiers if modifiers.shift => Some("shift"),
3763                    modifiers if modifiers.control => Some("control"),
3764                    modifiers if modifiers.alt => Some("alt"),
3765                    modifiers if modifiers.platform => Some("platform"),
3766                    modifiers if modifiers.function => Some("function"),
3767                    _ => None,
3768                };
3769                if let Some(key) = key {
3770                    keystroke = Some(Keystroke {
3771                        key: key.to_string(),
3772                        key_char: None,
3773                        modifiers: Modifiers::default(),
3774                    });
3775                }
3776            }
3777
3778            if self.pending_modifier.modifiers.number_of_modifiers() == 0
3779                && event.modifiers.number_of_modifiers() == 1
3780            {
3781                self.pending_modifier.saw_keystroke = false
3782            }
3783            self.pending_modifier.modifiers = event.modifiers
3784        } else if let Some(key_down_event) = event.downcast_ref::<KeyDownEvent>() {
3785            self.pending_modifier.saw_keystroke = true;
3786            keystroke = Some(key_down_event.keystroke.clone());
3787        }
3788
3789        let Some(keystroke) = keystroke else {
3790            self.finish_dispatch_key_event(event, dispatch_path, self.context_stack(), cx);
3791            return;
3792        };
3793
3794        cx.propagate_event = true;
3795        self.dispatch_keystroke_interceptors(event, self.context_stack(), cx);
3796        if !cx.propagate_event {
3797            self.finish_dispatch_key_event(event, dispatch_path, self.context_stack(), cx);
3798            return;
3799        }
3800
3801        let mut currently_pending = self.pending_input.take().unwrap_or_default();
3802        if currently_pending.focus.is_some() && currently_pending.focus != self.focus {
3803            currently_pending = PendingInput::default();
3804        }
3805
3806        let match_result = self.rendered_frame.dispatch_tree.dispatch_key(
3807            currently_pending.keystrokes,
3808            keystroke,
3809            &dispatch_path,
3810        );
3811
3812        if !match_result.to_replay.is_empty() {
3813            self.replay_pending_input(match_result.to_replay, cx);
3814            cx.propagate_event = true;
3815        }
3816
3817        if !match_result.pending.is_empty() {
3818            currently_pending.keystrokes = match_result.pending;
3819            currently_pending.focus = self.focus;
3820            currently_pending.timer = Some(self.spawn(cx, async move |cx| {
3821                cx.background_executor.timer(Duration::from_secs(1)).await;
3822                cx.update(move |window, cx| {
3823                    let Some(currently_pending) = window
3824                        .pending_input
3825                        .take()
3826                        .filter(|pending| pending.focus == window.focus)
3827                    else {
3828                        return;
3829                    };
3830
3831                    let node_id = window.focus_node_id_in_rendered_frame(window.focus);
3832                    let dispatch_path = window.rendered_frame.dispatch_tree.dispatch_path(node_id);
3833
3834                    let to_replay = window
3835                        .rendered_frame
3836                        .dispatch_tree
3837                        .flush_dispatch(currently_pending.keystrokes, &dispatch_path);
3838
3839                    window.pending_input_changed(cx);
3840                    window.replay_pending_input(to_replay, cx)
3841                })
3842                .log_err();
3843            }));
3844            self.pending_input = Some(currently_pending);
3845            self.pending_input_changed(cx);
3846            cx.propagate_event = false;
3847            return;
3848        }
3849
3850        for binding in match_result.bindings {
3851            self.dispatch_action_on_node(node_id, binding.action.as_ref(), cx);
3852            if !cx.propagate_event {
3853                self.dispatch_keystroke_observers(
3854                    event,
3855                    Some(binding.action),
3856                    match_result.context_stack,
3857                    cx,
3858                );
3859                self.pending_input_changed(cx);
3860                return;
3861            }
3862        }
3863
3864        self.finish_dispatch_key_event(event, dispatch_path, match_result.context_stack, cx);
3865        self.pending_input_changed(cx);
3866    }
3867
3868    fn finish_dispatch_key_event(
3869        &mut self,
3870        event: &dyn Any,
3871        dispatch_path: SmallVec<[DispatchNodeId; 32]>,
3872        context_stack: Vec<KeyContext>,
3873        cx: &mut App,
3874    ) {
3875        self.dispatch_key_down_up_event(event, &dispatch_path, cx);
3876        if !cx.propagate_event {
3877            return;
3878        }
3879
3880        self.dispatch_modifiers_changed_event(event, &dispatch_path, cx);
3881        if !cx.propagate_event {
3882            return;
3883        }
3884
3885        self.dispatch_keystroke_observers(event, None, context_stack, cx);
3886    }
3887
3888    fn pending_input_changed(&mut self, cx: &mut App) {
3889        self.pending_input_observers
3890            .clone()
3891            .retain(&(), |callback| callback(self, cx));
3892    }
3893
3894    fn dispatch_key_down_up_event(
3895        &mut self,
3896        event: &dyn Any,
3897        dispatch_path: &SmallVec<[DispatchNodeId; 32]>,
3898        cx: &mut App,
3899    ) {
3900        // Capture phase
3901        for node_id in dispatch_path {
3902            let node = self.rendered_frame.dispatch_tree.node(*node_id);
3903
3904            for key_listener in node.key_listeners.clone() {
3905                key_listener(event, DispatchPhase::Capture, self, cx);
3906                if !cx.propagate_event {
3907                    return;
3908                }
3909            }
3910        }
3911
3912        // Bubble phase
3913        for node_id in dispatch_path.iter().rev() {
3914            // Handle low level key events
3915            let node = self.rendered_frame.dispatch_tree.node(*node_id);
3916            for key_listener in node.key_listeners.clone() {
3917                key_listener(event, DispatchPhase::Bubble, self, cx);
3918                if !cx.propagate_event {
3919                    return;
3920                }
3921            }
3922        }
3923    }
3924
3925    fn dispatch_modifiers_changed_event(
3926        &mut self,
3927        event: &dyn Any,
3928        dispatch_path: &SmallVec<[DispatchNodeId; 32]>,
3929        cx: &mut App,
3930    ) {
3931        let Some(event) = event.downcast_ref::<ModifiersChangedEvent>() else {
3932            return;
3933        };
3934        for node_id in dispatch_path.iter().rev() {
3935            let node = self.rendered_frame.dispatch_tree.node(*node_id);
3936            for listener in node.modifiers_changed_listeners.clone() {
3937                listener(event, self, cx);
3938                if !cx.propagate_event {
3939                    return;
3940                }
3941            }
3942        }
3943    }
3944
3945    /// Determine whether a potential multi-stroke key binding is in progress on this window.
3946    pub fn has_pending_keystrokes(&self) -> bool {
3947        self.pending_input.is_some()
3948    }
3949
3950    pub(crate) fn clear_pending_keystrokes(&mut self) {
3951        self.pending_input.take();
3952    }
3953
3954    /// Returns the currently pending input keystrokes that might result in a multi-stroke key binding.
3955    pub fn pending_input_keystrokes(&self) -> Option<&[Keystroke]> {
3956        self.pending_input
3957            .as_ref()
3958            .map(|pending_input| pending_input.keystrokes.as_slice())
3959    }
3960
3961    fn replay_pending_input(&mut self, replays: SmallVec<[Replay; 1]>, cx: &mut App) {
3962        let node_id = self.focus_node_id_in_rendered_frame(self.focus);
3963        let dispatch_path = self.rendered_frame.dispatch_tree.dispatch_path(node_id);
3964
3965        'replay: for replay in replays {
3966            let event = KeyDownEvent {
3967                keystroke: replay.keystroke.clone(),
3968                is_held: false,
3969            };
3970
3971            cx.propagate_event = true;
3972            for binding in replay.bindings {
3973                self.dispatch_action_on_node(node_id, binding.action.as_ref(), cx);
3974                if !cx.propagate_event {
3975                    self.dispatch_keystroke_observers(
3976                        &event,
3977                        Some(binding.action),
3978                        Vec::default(),
3979                        cx,
3980                    );
3981                    continue 'replay;
3982                }
3983            }
3984
3985            self.dispatch_key_down_up_event(&event, &dispatch_path, cx);
3986            if !cx.propagate_event {
3987                continue 'replay;
3988            }
3989            if let Some(input) = replay.keystroke.key_char.as_ref().cloned()
3990                && let Some(mut input_handler) = self.platform_window.take_input_handler()
3991            {
3992                input_handler.dispatch_input(&input, self, cx);
3993                self.platform_window.set_input_handler(input_handler)
3994            }
3995        }
3996    }
3997
3998    fn focus_node_id_in_rendered_frame(&self, focus_id: Option<FocusId>) -> DispatchNodeId {
3999        focus_id
4000            .and_then(|focus_id| {
4001                self.rendered_frame
4002                    .dispatch_tree
4003                    .focusable_node_id(focus_id)
4004            })
4005            .unwrap_or_else(|| self.rendered_frame.dispatch_tree.root_node_id())
4006    }
4007
4008    fn dispatch_action_on_node(
4009        &mut self,
4010        node_id: DispatchNodeId,
4011        action: &dyn Action,
4012        cx: &mut App,
4013    ) {
4014        let dispatch_path = self.rendered_frame.dispatch_tree.dispatch_path(node_id);
4015
4016        // Capture phase for global actions.
4017        cx.propagate_event = true;
4018        if let Some(mut global_listeners) = cx
4019            .global_action_listeners
4020            .remove(&action.as_any().type_id())
4021        {
4022            for listener in &global_listeners {
4023                listener(action.as_any(), DispatchPhase::Capture, cx);
4024                if !cx.propagate_event {
4025                    break;
4026                }
4027            }
4028
4029            global_listeners.extend(
4030                cx.global_action_listeners
4031                    .remove(&action.as_any().type_id())
4032                    .unwrap_or_default(),
4033            );
4034
4035            cx.global_action_listeners
4036                .insert(action.as_any().type_id(), global_listeners);
4037        }
4038
4039        if !cx.propagate_event {
4040            return;
4041        }
4042
4043        // Capture phase for window actions.
4044        for node_id in &dispatch_path {
4045            let node = self.rendered_frame.dispatch_tree.node(*node_id);
4046            for DispatchActionListener {
4047                action_type,
4048                listener,
4049            } in node.action_listeners.clone()
4050            {
4051                let any_action = action.as_any();
4052                if action_type == any_action.type_id() {
4053                    listener(any_action, DispatchPhase::Capture, self, cx);
4054
4055                    if !cx.propagate_event {
4056                        return;
4057                    }
4058                }
4059            }
4060        }
4061
4062        // Bubble phase for window actions.
4063        for node_id in dispatch_path.iter().rev() {
4064            let node = self.rendered_frame.dispatch_tree.node(*node_id);
4065            for DispatchActionListener {
4066                action_type,
4067                listener,
4068            } in node.action_listeners.clone()
4069            {
4070                let any_action = action.as_any();
4071                if action_type == any_action.type_id() {
4072                    cx.propagate_event = false; // Actions stop propagation by default during the bubble phase
4073                    listener(any_action, DispatchPhase::Bubble, self, cx);
4074
4075                    if !cx.propagate_event {
4076                        return;
4077                    }
4078                }
4079            }
4080        }
4081
4082        // Bubble phase for global actions.
4083        if let Some(mut global_listeners) = cx
4084            .global_action_listeners
4085            .remove(&action.as_any().type_id())
4086        {
4087            for listener in global_listeners.iter().rev() {
4088                cx.propagate_event = false; // Actions stop propagation by default during the bubble phase
4089
4090                listener(action.as_any(), DispatchPhase::Bubble, cx);
4091                if !cx.propagate_event {
4092                    break;
4093                }
4094            }
4095
4096            global_listeners.extend(
4097                cx.global_action_listeners
4098                    .remove(&action.as_any().type_id())
4099                    .unwrap_or_default(),
4100            );
4101
4102            cx.global_action_listeners
4103                .insert(action.as_any().type_id(), global_listeners);
4104        }
4105    }
4106
4107    /// Register the given handler to be invoked whenever the global of the given type
4108    /// is updated.
4109    pub fn observe_global<G: Global>(
4110        &mut self,
4111        cx: &mut App,
4112        f: impl Fn(&mut Window, &mut App) + 'static,
4113    ) -> Subscription {
4114        let window_handle = self.handle;
4115        let (subscription, activate) = cx.global_observers.insert(
4116            TypeId::of::<G>(),
4117            Box::new(move |cx| {
4118                window_handle
4119                    .update(cx, |_, window, cx| f(window, cx))
4120                    .is_ok()
4121            }),
4122        );
4123        cx.defer(move |_| activate());
4124        subscription
4125    }
4126
4127    /// Focus the current window and bring it to the foreground at the platform level.
4128    pub fn activate_window(&self) {
4129        self.platform_window.activate();
4130    }
4131
4132    /// Minimize the current window at the platform level.
4133    pub fn minimize_window(&self) {
4134        self.platform_window.minimize();
4135    }
4136
4137    /// Toggle full screen status on the current window at the platform level.
4138    pub fn toggle_fullscreen(&self) {
4139        self.platform_window.toggle_fullscreen();
4140    }
4141
4142    /// Updates the IME panel position suggestions for languages like japanese, chinese.
4143    pub fn invalidate_character_coordinates(&self) {
4144        self.on_next_frame(|window, cx| {
4145            if let Some(mut input_handler) = window.platform_window.take_input_handler() {
4146                if let Some(bounds) = input_handler.selected_bounds(window, cx) {
4147                    window.platform_window.update_ime_position(bounds);
4148                }
4149                window.platform_window.set_input_handler(input_handler);
4150            }
4151        });
4152    }
4153
4154    /// Present a platform dialog.
4155    /// The provided message will be presented, along with buttons for each answer.
4156    /// When a button is clicked, the returned Receiver will receive the index of the clicked button.
4157    pub fn prompt<T>(
4158        &mut self,
4159        level: PromptLevel,
4160        message: &str,
4161        detail: Option<&str>,
4162        answers: &[T],
4163        cx: &mut App,
4164    ) -> oneshot::Receiver<usize>
4165    where
4166        T: Clone + Into<PromptButton>,
4167    {
4168        let prompt_builder = cx.prompt_builder.take();
4169        let Some(prompt_builder) = prompt_builder else {
4170            unreachable!("Re-entrant window prompting is not supported by GPUI");
4171        };
4172
4173        let answers = answers
4174            .iter()
4175            .map(|answer| answer.clone().into())
4176            .collect::<Vec<_>>();
4177
4178        let receiver = match &prompt_builder {
4179            PromptBuilder::Default => self
4180                .platform_window
4181                .prompt(level, message, detail, &answers)
4182                .unwrap_or_else(|| {
4183                    self.build_custom_prompt(&prompt_builder, level, message, detail, &answers, cx)
4184                }),
4185            PromptBuilder::Custom(_) => {
4186                self.build_custom_prompt(&prompt_builder, level, message, detail, &answers, cx)
4187            }
4188        };
4189
4190        cx.prompt_builder = Some(prompt_builder);
4191
4192        receiver
4193    }
4194
4195    fn build_custom_prompt(
4196        &mut self,
4197        prompt_builder: &PromptBuilder,
4198        level: PromptLevel,
4199        message: &str,
4200        detail: Option<&str>,
4201        answers: &[PromptButton],
4202        cx: &mut App,
4203    ) -> oneshot::Receiver<usize> {
4204        let (sender, receiver) = oneshot::channel();
4205        let handle = PromptHandle::new(sender);
4206        let handle = (prompt_builder)(level, message, detail, answers, handle, self, cx);
4207        self.prompt = Some(handle);
4208        receiver
4209    }
4210
4211    /// Returns the current context stack.
4212    pub fn context_stack(&self) -> Vec<KeyContext> {
4213        let node_id = self.focus_node_id_in_rendered_frame(self.focus);
4214        let dispatch_tree = &self.rendered_frame.dispatch_tree;
4215        dispatch_tree
4216            .dispatch_path(node_id)
4217            .iter()
4218            .filter_map(move |&node_id| dispatch_tree.node(node_id).context.clone())
4219            .collect()
4220    }
4221
4222    /// Returns all available actions for the focused element.
4223    pub fn available_actions(&self, cx: &App) -> Vec<Box<dyn Action>> {
4224        let node_id = self.focus_node_id_in_rendered_frame(self.focus);
4225        let mut actions = self.rendered_frame.dispatch_tree.available_actions(node_id);
4226        for action_type in cx.global_action_listeners.keys() {
4227            if let Err(ix) = actions.binary_search_by_key(action_type, |a| a.as_any().type_id()) {
4228                let action = cx.actions.build_action_type(action_type).ok();
4229                if let Some(action) = action {
4230                    actions.insert(ix, action);
4231                }
4232            }
4233        }
4234        actions
4235    }
4236
4237    /// Returns key bindings that invoke an action on the currently focused element. Bindings are
4238    /// returned in the order they were added. For display, the last binding should take precedence.
4239    pub fn bindings_for_action(&self, action: &dyn Action) -> Vec<KeyBinding> {
4240        self.rendered_frame
4241            .dispatch_tree
4242            .bindings_for_action(action, &self.rendered_frame.dispatch_tree.context_stack)
4243    }
4244
4245    /// Returns the highest precedence key binding that invokes an action on the currently focused
4246    /// element. This is more efficient than getting the last result of `bindings_for_action`.
4247    pub fn highest_precedence_binding_for_action(&self, action: &dyn Action) -> Option<KeyBinding> {
4248        self.rendered_frame
4249            .dispatch_tree
4250            .highest_precedence_binding_for_action(
4251                action,
4252                &self.rendered_frame.dispatch_tree.context_stack,
4253            )
4254    }
4255
4256    /// Returns the key bindings for an action in a context.
4257    pub fn bindings_for_action_in_context(
4258        &self,
4259        action: &dyn Action,
4260        context: KeyContext,
4261    ) -> Vec<KeyBinding> {
4262        let dispatch_tree = &self.rendered_frame.dispatch_tree;
4263        dispatch_tree.bindings_for_action(action, &[context])
4264    }
4265
4266    /// Returns the highest precedence key binding for an action in a context. This is more
4267    /// efficient than getting the last result of `bindings_for_action_in_context`.
4268    pub fn highest_precedence_binding_for_action_in_context(
4269        &self,
4270        action: &dyn Action,
4271        context: KeyContext,
4272    ) -> Option<KeyBinding> {
4273        let dispatch_tree = &self.rendered_frame.dispatch_tree;
4274        dispatch_tree.highest_precedence_binding_for_action(action, &[context])
4275    }
4276
4277    /// Returns any bindings that would invoke an action on the given focus handle if it were
4278    /// focused. Bindings are returned in the order they were added. For display, the last binding
4279    /// should take precedence.
4280    pub fn bindings_for_action_in(
4281        &self,
4282        action: &dyn Action,
4283        focus_handle: &FocusHandle,
4284    ) -> Vec<KeyBinding> {
4285        let dispatch_tree = &self.rendered_frame.dispatch_tree;
4286        let Some(context_stack) = self.context_stack_for_focus_handle(focus_handle) else {
4287            return vec![];
4288        };
4289        dispatch_tree.bindings_for_action(action, &context_stack)
4290    }
4291
4292    /// Returns the highest precedence key binding that would invoke an action on the given focus
4293    /// handle if it were focused. This is more efficient than getting the last result of
4294    /// `bindings_for_action_in`.
4295    pub fn highest_precedence_binding_for_action_in(
4296        &self,
4297        action: &dyn Action,
4298        focus_handle: &FocusHandle,
4299    ) -> Option<KeyBinding> {
4300        let dispatch_tree = &self.rendered_frame.dispatch_tree;
4301        let context_stack = self.context_stack_for_focus_handle(focus_handle)?;
4302        dispatch_tree.highest_precedence_binding_for_action(action, &context_stack)
4303    }
4304
4305    fn context_stack_for_focus_handle(
4306        &self,
4307        focus_handle: &FocusHandle,
4308    ) -> Option<Vec<KeyContext>> {
4309        let dispatch_tree = &self.rendered_frame.dispatch_tree;
4310        let node_id = dispatch_tree.focusable_node_id(focus_handle.id)?;
4311        let context_stack: Vec<_> = dispatch_tree
4312            .dispatch_path(node_id)
4313            .into_iter()
4314            .filter_map(|node_id| dispatch_tree.node(node_id).context.clone())
4315            .collect();
4316        Some(context_stack)
4317    }
4318
4319    /// Returns a generic event listener that invokes the given listener with the view and context associated with the given view handle.
4320    pub fn listener_for<V: Render, E>(
4321        &self,
4322        view: &Entity<V>,
4323        f: impl Fn(&mut V, &E, &mut Window, &mut Context<V>) + 'static,
4324    ) -> impl Fn(&E, &mut Window, &mut App) + 'static {
4325        let view = view.downgrade();
4326        move |e: &E, window: &mut Window, cx: &mut App| {
4327            view.update(cx, |view, cx| f(view, e, window, cx)).ok();
4328        }
4329    }
4330
4331    /// Returns a generic handler that invokes the given handler with the view and context associated with the given view handle.
4332    pub fn handler_for<E: 'static, Callback: Fn(&mut E, &mut Window, &mut Context<E>) + 'static>(
4333        &self,
4334        entity: &Entity<E>,
4335        f: Callback,
4336    ) -> impl Fn(&mut Window, &mut App) + 'static {
4337        let entity = entity.downgrade();
4338        move |window: &mut Window, cx: &mut App| {
4339            entity.update(cx, |entity, cx| f(entity, window, cx)).ok();
4340        }
4341    }
4342
4343    /// Register a callback that can interrupt the closing of the current window based the returned boolean.
4344    /// If the callback returns false, the window won't be closed.
4345    pub fn on_window_should_close(
4346        &self,
4347        cx: &App,
4348        f: impl Fn(&mut Window, &mut App) -> bool + 'static,
4349    ) {
4350        let mut cx = self.to_async(cx);
4351        self.platform_window.on_should_close(Box::new(move || {
4352            cx.update(|window, cx| f(window, cx)).unwrap_or(true)
4353        }))
4354    }
4355
4356    /// Register an action listener on the window for the next frame. The type of action
4357    /// is determined by the first parameter of the given listener. When the next frame is rendered
4358    /// the listener will be cleared.
4359    ///
4360    /// This is a fairly low-level method, so prefer using action handlers on elements unless you have
4361    /// a specific need to register a global listener.
4362    pub fn on_action(
4363        &mut self,
4364        action_type: TypeId,
4365        listener: impl Fn(&dyn Any, DispatchPhase, &mut Window, &mut App) + 'static,
4366    ) {
4367        self.next_frame
4368            .dispatch_tree
4369            .on_action(action_type, Rc::new(listener));
4370    }
4371
4372    /// Register an action listener on the window for the next frame if the condition is true.
4373    /// The type of action is determined by the first parameter of the given listener.
4374    /// When the next frame is rendered the listener will be cleared.
4375    ///
4376    /// This is a fairly low-level method, so prefer using action handlers on elements unless you have
4377    /// a specific need to register a global listener.
4378    pub fn on_action_when(
4379        &mut self,
4380        condition: bool,
4381        action_type: TypeId,
4382        listener: impl Fn(&dyn Any, DispatchPhase, &mut Window, &mut App) + 'static,
4383    ) {
4384        if condition {
4385            self.next_frame
4386                .dispatch_tree
4387                .on_action(action_type, Rc::new(listener));
4388        }
4389    }
4390
4391    /// Read information about the GPU backing this window.
4392    /// Currently returns None on Mac and Windows.
4393    pub fn gpu_specs(&self) -> Option<GpuSpecs> {
4394        self.platform_window.gpu_specs()
4395    }
4396
4397    /// Perform titlebar double-click action.
4398    /// This is macOS specific.
4399    pub fn titlebar_double_click(&self) {
4400        self.platform_window.titlebar_double_click();
4401    }
4402
4403    /// Gets the window's title at the platform level.
4404    /// This is macOS specific.
4405    pub fn window_title(&self) -> String {
4406        self.platform_window.get_title()
4407    }
4408
4409    /// Returns a list of all tabbed windows and their titles.
4410    /// This is macOS specific.
4411    pub fn tabbed_windows(&self) -> Option<Vec<SystemWindowTab>> {
4412        self.platform_window.tabbed_windows()
4413    }
4414
4415    /// Returns the tab bar visibility.
4416    /// This is macOS specific.
4417    pub fn tab_bar_visible(&self) -> bool {
4418        self.platform_window.tab_bar_visible()
4419    }
4420
4421    /// Merges all open windows into a single tabbed window.
4422    /// This is macOS specific.
4423    pub fn merge_all_windows(&self) {
4424        self.platform_window.merge_all_windows()
4425    }
4426
4427    /// Moves the tab to a new containing window.
4428    /// This is macOS specific.
4429    pub fn move_tab_to_new_window(&self) {
4430        self.platform_window.move_tab_to_new_window()
4431    }
4432
4433    /// Shows or hides the window tab overview.
4434    /// This is macOS specific.
4435    pub fn toggle_window_tab_overview(&self) {
4436        self.platform_window.toggle_window_tab_overview()
4437    }
4438
4439    /// Sets the tabbing identifier for the window.
4440    /// This is macOS specific.
4441    pub fn set_tabbing_identifier(&self, tabbing_identifier: Option<String>) {
4442        self.platform_window
4443            .set_tabbing_identifier(tabbing_identifier)
4444    }
4445
4446    /// Toggles the inspector mode on this window.
4447    #[cfg(any(feature = "inspector", debug_assertions))]
4448    pub fn toggle_inspector(&mut self, cx: &mut App) {
4449        self.inspector = match self.inspector {
4450            None => Some(cx.new(|_| Inspector::new())),
4451            Some(_) => None,
4452        };
4453        self.refresh();
4454    }
4455
4456    /// Returns true if the window is in inspector mode.
4457    pub fn is_inspector_picking(&self, _cx: &App) -> bool {
4458        #[cfg(any(feature = "inspector", debug_assertions))]
4459        {
4460            if let Some(inspector) = &self.inspector {
4461                return inspector.read(_cx).is_picking();
4462            }
4463        }
4464        false
4465    }
4466
4467    /// Executes the provided function with mutable access to an inspector state.
4468    #[cfg(any(feature = "inspector", debug_assertions))]
4469    pub fn with_inspector_state<T: 'static, R>(
4470        &mut self,
4471        _inspector_id: Option<&crate::InspectorElementId>,
4472        cx: &mut App,
4473        f: impl FnOnce(&mut Option<T>, &mut Self) -> R,
4474    ) -> R {
4475        if let Some(inspector_id) = _inspector_id
4476            && let Some(inspector) = &self.inspector
4477        {
4478            let inspector = inspector.clone();
4479            let active_element_id = inspector.read(cx).active_element_id();
4480            if Some(inspector_id) == active_element_id {
4481                return inspector.update(cx, |inspector, _cx| {
4482                    inspector.with_active_element_state(self, f)
4483                });
4484            }
4485        }
4486        f(&mut None, self)
4487    }
4488
4489    #[cfg(any(feature = "inspector", debug_assertions))]
4490    pub(crate) fn build_inspector_element_id(
4491        &mut self,
4492        path: crate::InspectorElementPath,
4493    ) -> crate::InspectorElementId {
4494        self.invalidator.debug_assert_paint_or_prepaint();
4495        let path = Rc::new(path);
4496        let next_instance_id = self
4497            .next_frame
4498            .next_inspector_instance_ids
4499            .entry(path.clone())
4500            .or_insert(0);
4501        let instance_id = *next_instance_id;
4502        *next_instance_id += 1;
4503        crate::InspectorElementId { path, instance_id }
4504    }
4505
4506    #[cfg(any(feature = "inspector", debug_assertions))]
4507    fn prepaint_inspector(&mut self, inspector_width: Pixels, cx: &mut App) -> Option<AnyElement> {
4508        if let Some(inspector) = self.inspector.take() {
4509            let mut inspector_element = AnyView::from(inspector.clone()).into_any_element();
4510            inspector_element.prepaint_as_root(
4511                point(self.viewport_size.width - inspector_width, px(0.0)),
4512                size(inspector_width, self.viewport_size.height).into(),
4513                self,
4514                cx,
4515            );
4516            self.inspector = Some(inspector);
4517            Some(inspector_element)
4518        } else {
4519            None
4520        }
4521    }
4522
4523    #[cfg(any(feature = "inspector", debug_assertions))]
4524    fn paint_inspector(&mut self, mut inspector_element: Option<AnyElement>, cx: &mut App) {
4525        if let Some(mut inspector_element) = inspector_element {
4526            inspector_element.paint(self, cx);
4527        };
4528    }
4529
4530    /// Registers a hitbox that can be used for inspector picking mode, allowing users to select and
4531    /// inspect UI elements by clicking on them.
4532    #[cfg(any(feature = "inspector", debug_assertions))]
4533    pub fn insert_inspector_hitbox(
4534        &mut self,
4535        hitbox_id: HitboxId,
4536        inspector_id: Option<&crate::InspectorElementId>,
4537        cx: &App,
4538    ) {
4539        self.invalidator.debug_assert_paint_or_prepaint();
4540        if !self.is_inspector_picking(cx) {
4541            return;
4542        }
4543        if let Some(inspector_id) = inspector_id {
4544            self.next_frame
4545                .inspector_hitboxes
4546                .insert(hitbox_id, inspector_id.clone());
4547        }
4548    }
4549
4550    #[cfg(any(feature = "inspector", debug_assertions))]
4551    fn paint_inspector_hitbox(&mut self, cx: &App) {
4552        if let Some(inspector) = self.inspector.as_ref() {
4553            let inspector = inspector.read(cx);
4554            if let Some((hitbox_id, _)) = self.hovered_inspector_hitbox(inspector, &self.next_frame)
4555                && let Some(hitbox) = self
4556                    .next_frame
4557                    .hitboxes
4558                    .iter()
4559                    .find(|hitbox| hitbox.id == hitbox_id)
4560            {
4561                self.paint_quad(crate::fill(hitbox.bounds, crate::rgba(0x61afef4d)));
4562            }
4563        }
4564    }
4565
4566    #[cfg(any(feature = "inspector", debug_assertions))]
4567    fn handle_inspector_mouse_event(&mut self, event: &dyn Any, cx: &mut App) {
4568        let Some(inspector) = self.inspector.clone() else {
4569            return;
4570        };
4571        if event.downcast_ref::<MouseMoveEvent>().is_some() {
4572            inspector.update(cx, |inspector, _cx| {
4573                if let Some((_, inspector_id)) =
4574                    self.hovered_inspector_hitbox(inspector, &self.rendered_frame)
4575                {
4576                    inspector.hover(inspector_id, self);
4577                }
4578            });
4579        } else if event.downcast_ref::<crate::MouseDownEvent>().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.select(inspector_id, self);
4585                }
4586            });
4587        } else if let Some(event) = event.downcast_ref::<crate::ScrollWheelEvent>() {
4588            // This should be kept in sync with SCROLL_LINES in x11 platform.
4589            const SCROLL_LINES: f32 = 3.0;
4590            const SCROLL_PIXELS_PER_LAYER: f32 = 36.0;
4591            let delta_y = event
4592                .delta
4593                .pixel_delta(px(SCROLL_PIXELS_PER_LAYER / SCROLL_LINES))
4594                .y;
4595            if let Some(inspector) = self.inspector.clone() {
4596                inspector.update(cx, |inspector, _cx| {
4597                    if let Some(depth) = inspector.pick_depth.as_mut() {
4598                        *depth += f32::from(delta_y) / SCROLL_PIXELS_PER_LAYER;
4599                        let max_depth = self.mouse_hit_test.ids.len() as f32 - 0.5;
4600                        if *depth < 0.0 {
4601                            *depth = 0.0;
4602                        } else if *depth > max_depth {
4603                            *depth = max_depth;
4604                        }
4605                        if let Some((_, inspector_id)) =
4606                            self.hovered_inspector_hitbox(inspector, &self.rendered_frame)
4607                        {
4608                            inspector.set_active_element_id(inspector_id, self);
4609                        }
4610                    }
4611                });
4612            }
4613        }
4614    }
4615
4616    #[cfg(any(feature = "inspector", debug_assertions))]
4617    fn hovered_inspector_hitbox(
4618        &self,
4619        inspector: &Inspector,
4620        frame: &Frame,
4621    ) -> Option<(HitboxId, crate::InspectorElementId)> {
4622        if let Some(pick_depth) = inspector.pick_depth {
4623            let depth = (pick_depth as i64).try_into().unwrap_or(0);
4624            let max_skipped = self.mouse_hit_test.ids.len().saturating_sub(1);
4625            let skip_count = (depth as usize).min(max_skipped);
4626            for hitbox_id in self.mouse_hit_test.ids.iter().skip(skip_count) {
4627                if let Some(inspector_id) = frame.inspector_hitboxes.get(hitbox_id) {
4628                    return Some((*hitbox_id, inspector_id.clone()));
4629                }
4630            }
4631        }
4632        None
4633    }
4634
4635    /// For testing: set the current modifier keys state.
4636    /// This does not generate any events.
4637    #[cfg(any(test, feature = "test-support"))]
4638    pub fn set_modifiers(&mut self, modifiers: Modifiers) {
4639        self.modifiers = modifiers;
4640    }
4641}
4642
4643// #[derive(Clone, Copy, Eq, PartialEq, Hash)]
4644slotmap::new_key_type! {
4645    /// A unique identifier for a window.
4646    pub struct WindowId;
4647}
4648
4649impl WindowId {
4650    /// Converts this window ID to a `u64`.
4651    pub fn as_u64(&self) -> u64 {
4652        self.0.as_ffi()
4653    }
4654}
4655
4656impl From<u64> for WindowId {
4657    fn from(value: u64) -> Self {
4658        WindowId(slotmap::KeyData::from_ffi(value))
4659    }
4660}
4661
4662/// A handle to a window with a specific root view type.
4663/// Note that this does not keep the window alive on its own.
4664#[derive(Deref, DerefMut)]
4665pub struct WindowHandle<V> {
4666    #[deref]
4667    #[deref_mut]
4668    pub(crate) any_handle: AnyWindowHandle,
4669    state_type: PhantomData<fn(V) -> V>,
4670}
4671
4672impl<V> Debug for WindowHandle<V> {
4673    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
4674        f.debug_struct("WindowHandle")
4675            .field("any_handle", &self.any_handle.id.as_u64())
4676            .finish()
4677    }
4678}
4679
4680impl<V: 'static + Render> WindowHandle<V> {
4681    /// Creates a new handle from a window ID.
4682    /// This does not check if the root type of the window is `V`.
4683    pub fn new(id: WindowId) -> Self {
4684        WindowHandle {
4685            any_handle: AnyWindowHandle {
4686                id,
4687                state_type: TypeId::of::<V>(),
4688            },
4689            state_type: PhantomData,
4690        }
4691    }
4692
4693    /// Get the root view out of this window.
4694    ///
4695    /// This will fail if the window is closed or if the root view's type does not match `V`.
4696    #[cfg(any(test, feature = "test-support"))]
4697    pub fn root<C>(&self, cx: &mut C) -> Result<Entity<V>>
4698    where
4699        C: AppContext,
4700    {
4701        crate::Flatten::flatten(cx.update_window(self.any_handle, |root_view, _, _| {
4702            root_view
4703                .downcast::<V>()
4704                .map_err(|_| anyhow!("the type of the window's root view has changed"))
4705        }))
4706    }
4707
4708    /// Updates the root view of this window.
4709    ///
4710    /// This will fail if the window has been closed or if the root view's type does not match
4711    pub fn update<C, R>(
4712        &self,
4713        cx: &mut C,
4714        update: impl FnOnce(&mut V, &mut Window, &mut Context<V>) -> R,
4715    ) -> Result<R>
4716    where
4717        C: AppContext,
4718    {
4719        cx.update_window(self.any_handle, |root_view, window, cx| {
4720            let view = root_view
4721                .downcast::<V>()
4722                .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
4723
4724            Ok(view.update(cx, |view, cx| update(view, window, cx)))
4725        })?
4726    }
4727
4728    /// Read the root view out of this window.
4729    ///
4730    /// This will fail if the window is closed or if the root view's type does not match `V`.
4731    pub fn read<'a>(&self, cx: &'a App) -> Result<&'a V> {
4732        let x = cx
4733            .windows
4734            .get(self.id)
4735            .and_then(|window| {
4736                window
4737                    .as_deref()
4738                    .and_then(|window| window.root.clone())
4739                    .map(|root_view| root_view.downcast::<V>())
4740            })
4741            .context("window not found")?
4742            .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
4743
4744        Ok(x.read(cx))
4745    }
4746
4747    /// Read the root view out of this window, with a callback
4748    ///
4749    /// This will fail if the window is closed or if the root view's type does not match `V`.
4750    pub fn read_with<C, R>(&self, cx: &C, read_with: impl FnOnce(&V, &App) -> R) -> Result<R>
4751    where
4752        C: AppContext,
4753    {
4754        cx.read_window(self, |root_view, cx| read_with(root_view.read(cx), cx))
4755    }
4756
4757    /// Read the root view pointer off of this window.
4758    ///
4759    /// This will fail if the window is closed or if the root view's type does not match `V`.
4760    pub fn entity<C>(&self, cx: &C) -> Result<Entity<V>>
4761    where
4762        C: AppContext,
4763    {
4764        cx.read_window(self, |root_view, _cx| root_view)
4765    }
4766
4767    /// Check if this window is 'active'.
4768    ///
4769    /// Will return `None` if the window is closed or currently
4770    /// borrowed.
4771    pub fn is_active(&self, cx: &mut App) -> Option<bool> {
4772        cx.update_window(self.any_handle, |_, window, _| window.is_window_active())
4773            .ok()
4774    }
4775}
4776
4777impl<V> Copy for WindowHandle<V> {}
4778
4779impl<V> Clone for WindowHandle<V> {
4780    fn clone(&self) -> Self {
4781        *self
4782    }
4783}
4784
4785impl<V> PartialEq for WindowHandle<V> {
4786    fn eq(&self, other: &Self) -> bool {
4787        self.any_handle == other.any_handle
4788    }
4789}
4790
4791impl<V> Eq for WindowHandle<V> {}
4792
4793impl<V> Hash for WindowHandle<V> {
4794    fn hash<H: Hasher>(&self, state: &mut H) {
4795        self.any_handle.hash(state);
4796    }
4797}
4798
4799impl<V: 'static> From<WindowHandle<V>> for AnyWindowHandle {
4800    fn from(val: WindowHandle<V>) -> Self {
4801        val.any_handle
4802    }
4803}
4804
4805/// A handle to a window with any root view type, which can be downcast to a window with a specific root view type.
4806#[derive(Copy, Clone, PartialEq, Eq, Hash)]
4807pub struct AnyWindowHandle {
4808    pub(crate) id: WindowId,
4809    state_type: TypeId,
4810}
4811
4812impl AnyWindowHandle {
4813    /// Get the ID of this window.
4814    pub fn window_id(&self) -> WindowId {
4815        self.id
4816    }
4817
4818    /// Attempt to convert this handle to a window handle with a specific root view type.
4819    /// If the types do not match, this will return `None`.
4820    pub fn downcast<T: 'static>(&self) -> Option<WindowHandle<T>> {
4821        if TypeId::of::<T>() == self.state_type {
4822            Some(WindowHandle {
4823                any_handle: *self,
4824                state_type: PhantomData,
4825            })
4826        } else {
4827            None
4828        }
4829    }
4830
4831    /// Updates the state of the root view of this window.
4832    ///
4833    /// This will fail if the window has been closed.
4834    pub fn update<C, R>(
4835        self,
4836        cx: &mut C,
4837        update: impl FnOnce(AnyView, &mut Window, &mut App) -> R,
4838    ) -> Result<R>
4839    where
4840        C: AppContext,
4841    {
4842        cx.update_window(self, update)
4843    }
4844
4845    /// Read the state of the root view of this window.
4846    ///
4847    /// This will fail if the window has been closed.
4848    pub fn read<T, C, R>(self, cx: &C, read: impl FnOnce(Entity<T>, &App) -> R) -> Result<R>
4849    where
4850        C: AppContext,
4851        T: 'static,
4852    {
4853        let view = self
4854            .downcast::<T>()
4855            .context("the type of the window's root view has changed")?;
4856
4857        cx.read_window(&view, read)
4858    }
4859}
4860
4861impl HasWindowHandle for Window {
4862    fn window_handle(&self) -> Result<raw_window_handle::WindowHandle<'_>, HandleError> {
4863        self.platform_window.window_handle()
4864    }
4865}
4866
4867impl HasDisplayHandle for Window {
4868    fn display_handle(
4869        &self,
4870    ) -> std::result::Result<raw_window_handle::DisplayHandle<'_>, HandleError> {
4871        self.platform_window.display_handle()
4872    }
4873}
4874
4875/// An identifier for an [`Element`].
4876///
4877/// Can be constructed with a string, a number, or both, as well
4878/// as other internal representations.
4879#[derive(Clone, Debug, Eq, PartialEq, Hash)]
4880pub enum ElementId {
4881    /// The ID of a View element
4882    View(EntityId),
4883    /// An integer ID.
4884    Integer(u64),
4885    /// A string based ID.
4886    Name(SharedString),
4887    /// A UUID.
4888    Uuid(Uuid),
4889    /// An ID that's equated with a focus handle.
4890    FocusHandle(FocusId),
4891    /// A combination of a name and an integer.
4892    NamedInteger(SharedString, u64),
4893    /// A path.
4894    Path(Arc<std::path::Path>),
4895    /// A code location.
4896    CodeLocation(core::panic::Location<'static>),
4897    /// A labeled child of an element.
4898    NamedChild(Arc<ElementId>, SharedString),
4899}
4900
4901impl ElementId {
4902    /// Constructs an `ElementId::NamedInteger` from a name and `usize`.
4903    pub fn named_usize(name: impl Into<SharedString>, integer: usize) -> ElementId {
4904        Self::NamedInteger(name.into(), integer as u64)
4905    }
4906}
4907
4908impl Display for ElementId {
4909    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
4910        match self {
4911            ElementId::View(entity_id) => write!(f, "view-{}", entity_id)?,
4912            ElementId::Integer(ix) => write!(f, "{}", ix)?,
4913            ElementId::Name(name) => write!(f, "{}", name)?,
4914            ElementId::FocusHandle(_) => write!(f, "FocusHandle")?,
4915            ElementId::NamedInteger(s, i) => write!(f, "{}-{}", s, i)?,
4916            ElementId::Uuid(uuid) => write!(f, "{}", uuid)?,
4917            ElementId::Path(path) => write!(f, "{}", path.display())?,
4918            ElementId::CodeLocation(location) => write!(f, "{}", location)?,
4919            ElementId::NamedChild(id, name) => write!(f, "{}-{}", id, name)?,
4920        }
4921
4922        Ok(())
4923    }
4924}
4925
4926impl TryInto<SharedString> for ElementId {
4927    type Error = anyhow::Error;
4928
4929    fn try_into(self) -> anyhow::Result<SharedString> {
4930        if let ElementId::Name(name) = self {
4931            Ok(name)
4932        } else {
4933            anyhow::bail!("element id is not string")
4934        }
4935    }
4936}
4937
4938impl From<usize> for ElementId {
4939    fn from(id: usize) -> Self {
4940        ElementId::Integer(id as u64)
4941    }
4942}
4943
4944impl From<i32> for ElementId {
4945    fn from(id: i32) -> Self {
4946        Self::Integer(id as u64)
4947    }
4948}
4949
4950impl From<SharedString> for ElementId {
4951    fn from(name: SharedString) -> Self {
4952        ElementId::Name(name)
4953    }
4954}
4955
4956impl From<Arc<std::path::Path>> for ElementId {
4957    fn from(path: Arc<std::path::Path>) -> Self {
4958        ElementId::Path(path)
4959    }
4960}
4961
4962impl From<&'static str> for ElementId {
4963    fn from(name: &'static str) -> Self {
4964        ElementId::Name(name.into())
4965    }
4966}
4967
4968impl<'a> From<&'a FocusHandle> for ElementId {
4969    fn from(handle: &'a FocusHandle) -> Self {
4970        ElementId::FocusHandle(handle.id)
4971    }
4972}
4973
4974impl From<(&'static str, EntityId)> for ElementId {
4975    fn from((name, id): (&'static str, EntityId)) -> Self {
4976        ElementId::NamedInteger(name.into(), id.as_u64())
4977    }
4978}
4979
4980impl From<(&'static str, usize)> for ElementId {
4981    fn from((name, id): (&'static str, usize)) -> Self {
4982        ElementId::NamedInteger(name.into(), id as u64)
4983    }
4984}
4985
4986impl From<(SharedString, usize)> for ElementId {
4987    fn from((name, id): (SharedString, usize)) -> Self {
4988        ElementId::NamedInteger(name, id as u64)
4989    }
4990}
4991
4992impl From<(&'static str, u64)> for ElementId {
4993    fn from((name, id): (&'static str, u64)) -> Self {
4994        ElementId::NamedInteger(name.into(), id)
4995    }
4996}
4997
4998impl From<Uuid> for ElementId {
4999    fn from(value: Uuid) -> Self {
5000        Self::Uuid(value)
5001    }
5002}
5003
5004impl From<(&'static str, u32)> for ElementId {
5005    fn from((name, id): (&'static str, u32)) -> Self {
5006        ElementId::NamedInteger(name.into(), id.into())
5007    }
5008}
5009
5010impl<T: Into<SharedString>> From<(ElementId, T)> for ElementId {
5011    fn from((id, name): (ElementId, T)) -> Self {
5012        ElementId::NamedChild(Arc::new(id), name.into())
5013    }
5014}
5015
5016impl From<&'static core::panic::Location<'static>> for ElementId {
5017    fn from(location: &'static core::panic::Location<'static>) -> Self {
5018        ElementId::CodeLocation(*location)
5019    }
5020}
5021
5022/// A rectangle to be rendered in the window at the given position and size.
5023/// Passed as an argument [`Window::paint_quad`].
5024#[derive(Clone)]
5025pub struct PaintQuad {
5026    /// The bounds of the quad within the window.
5027    pub bounds: Bounds<Pixels>,
5028    /// The radii of the quad's corners.
5029    pub corner_radii: Corners<Pixels>,
5030    /// The background color of the quad.
5031    pub background: Background,
5032    /// The widths of the quad's borders.
5033    pub border_widths: Edges<Pixels>,
5034    /// The color of the quad's borders.
5035    pub border_color: Hsla,
5036    /// The style of the quad's borders.
5037    pub border_style: BorderStyle,
5038}
5039
5040impl PaintQuad {
5041    /// Sets the corner radii of the quad.
5042    pub fn corner_radii(self, corner_radii: impl Into<Corners<Pixels>>) -> Self {
5043        PaintQuad {
5044            corner_radii: corner_radii.into(),
5045            ..self
5046        }
5047    }
5048
5049    /// Sets the border widths of the quad.
5050    pub fn border_widths(self, border_widths: impl Into<Edges<Pixels>>) -> Self {
5051        PaintQuad {
5052            border_widths: border_widths.into(),
5053            ..self
5054        }
5055    }
5056
5057    /// Sets the border color of the quad.
5058    pub fn border_color(self, border_color: impl Into<Hsla>) -> Self {
5059        PaintQuad {
5060            border_color: border_color.into(),
5061            ..self
5062        }
5063    }
5064
5065    /// Sets the background color of the quad.
5066    pub fn background(self, background: impl Into<Background>) -> Self {
5067        PaintQuad {
5068            background: background.into(),
5069            ..self
5070        }
5071    }
5072}
5073
5074/// Creates a quad with the given parameters.
5075pub fn quad(
5076    bounds: Bounds<Pixels>,
5077    corner_radii: impl Into<Corners<Pixels>>,
5078    background: impl Into<Background>,
5079    border_widths: impl Into<Edges<Pixels>>,
5080    border_color: impl Into<Hsla>,
5081    border_style: BorderStyle,
5082) -> PaintQuad {
5083    PaintQuad {
5084        bounds,
5085        corner_radii: corner_radii.into(),
5086        background: background.into(),
5087        border_widths: border_widths.into(),
5088        border_color: border_color.into(),
5089        border_style,
5090    }
5091}
5092
5093/// Creates a filled quad with the given bounds and background color.
5094pub fn fill(bounds: impl Into<Bounds<Pixels>>, background: impl Into<Background>) -> PaintQuad {
5095    PaintQuad {
5096        bounds: bounds.into(),
5097        corner_radii: (0.).into(),
5098        background: background.into(),
5099        border_widths: (0.).into(),
5100        border_color: transparent_black(),
5101        border_style: BorderStyle::default(),
5102    }
5103}
5104
5105/// Creates a rectangle outline with the given bounds, border color, and a 1px border width
5106pub fn outline(
5107    bounds: impl Into<Bounds<Pixels>>,
5108    border_color: impl Into<Hsla>,
5109    border_style: BorderStyle,
5110) -> PaintQuad {
5111    PaintQuad {
5112        bounds: bounds.into(),
5113        corner_radii: (0.).into(),
5114        background: transparent_black().into(),
5115        border_widths: (1.).into(),
5116        border_color: border_color.into(),
5117        border_style,
5118    }
5119}