window.rs

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