window.rs

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