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