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