window.rs

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