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    SMOOTH_SVG_SCALE_FACTOR, 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_painting(&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_painting() {
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        let params = RenderSvgParams {
2557            path,
2558            size: bounds.size.map(|pixels| {
2559                DevicePixels::from((pixels.0 * SMOOTH_SVG_SCALE_FACTOR).ceil() as i32)
2560            }),
2561        };
2562
2563        let Some(tile) =
2564            self.sprite_atlas
2565                .get_or_insert_with(&params.clone().into(), &mut || {
2566                    let Some(bytes) = cx.svg_renderer.render(&params)? else {
2567                        return Ok(None);
2568                    };
2569                    Ok(Some((params.size, Cow::Owned(bytes))))
2570                })?
2571        else {
2572            return Ok(());
2573        };
2574        let content_mask = self.content_mask().scale(scale_factor);
2575
2576        self.next_frame.scene.insert_primitive(MonochromeSprite {
2577            order: 0,
2578            pad: 0,
2579            bounds: bounds
2580                .map_origin(|origin| origin.floor())
2581                .map_size(|size| size.ceil()),
2582            content_mask,
2583            color: color.opacity(element_opacity),
2584            tile,
2585            transformation,
2586        });
2587
2588        Ok(())
2589    }
2590
2591    /// Paint an image into the scene for the next frame at the current z-index.
2592    /// This method will panic if the frame_index is not valid
2593    ///
2594    /// This method should only be called as part of the paint phase of element drawing.
2595    pub fn paint_image(
2596        &mut self,
2597        bounds: Bounds<Pixels>,
2598        corner_radii: Corners<Pixels>,
2599        data: Arc<RenderImage>,
2600        frame_index: usize,
2601        grayscale: bool,
2602    ) -> Result<()> {
2603        self.invalidator.debug_assert_paint();
2604
2605        let scale_factor = self.scale_factor();
2606        let bounds = bounds.scale(scale_factor);
2607        let params = RenderImageParams {
2608            image_id: data.id,
2609            frame_index,
2610        };
2611
2612        let tile = self
2613            .sprite_atlas
2614            .get_or_insert_with(&params.clone().into(), &mut || {
2615                Ok(Some((
2616                    data.size(frame_index),
2617                    Cow::Borrowed(
2618                        data.as_bytes(frame_index)
2619                            .expect("It's the caller's job to pass a valid frame index"),
2620                    ),
2621                )))
2622            })?
2623            .expect("Callback above only returns Some");
2624        let content_mask = self.content_mask().scale(scale_factor);
2625        let corner_radii = corner_radii.scale(scale_factor);
2626        let opacity = self.element_opacity();
2627
2628        self.next_frame.scene.insert_primitive(PolychromeSprite {
2629            order: 0,
2630            pad: 0,
2631            grayscale,
2632            bounds,
2633            content_mask,
2634            corner_radii,
2635            tile,
2636            opacity,
2637        });
2638        Ok(())
2639    }
2640
2641    /// Paint a surface into the scene for the next frame at the current z-index.
2642    ///
2643    /// This method should only be called as part of the paint phase of element drawing.
2644    #[cfg(target_os = "macos")]
2645    pub fn paint_surface(&mut self, bounds: Bounds<Pixels>, image_buffer: CVImageBuffer) {
2646        use crate::PaintSurface;
2647
2648        self.invalidator.debug_assert_paint();
2649
2650        let scale_factor = self.scale_factor();
2651        let bounds = bounds.scale(scale_factor);
2652        let content_mask = self.content_mask().scale(scale_factor);
2653        self.next_frame.scene.insert_primitive(PaintSurface {
2654            order: 0,
2655            bounds,
2656            content_mask,
2657            image_buffer,
2658        });
2659    }
2660
2661    /// Removes an image from the sprite atlas.
2662    pub fn drop_image(&mut self, data: Arc<RenderImage>) -> Result<()> {
2663        for frame_index in 0..data.frame_count() {
2664            let params = RenderImageParams {
2665                image_id: data.id,
2666                frame_index,
2667            };
2668
2669            self.sprite_atlas.remove(&params.clone().into());
2670        }
2671
2672        Ok(())
2673    }
2674
2675    /// Add a node to the layout tree for the current frame. Takes the `Style` of the element for which
2676    /// layout is being requested, along with the layout ids of any children. This method is called during
2677    /// calls to the [`Element::request_layout`] trait method and enables any element to participate in layout.
2678    ///
2679    /// This method should only be called as part of the request_layout or prepaint phase of element drawing.
2680    #[must_use]
2681    pub fn request_layout(
2682        &mut self,
2683        style: Style,
2684        children: impl IntoIterator<Item = LayoutId>,
2685        cx: &mut App,
2686    ) -> LayoutId {
2687        self.invalidator.debug_assert_prepaint();
2688
2689        cx.layout_id_buffer.clear();
2690        cx.layout_id_buffer.extend(children);
2691        let rem_size = self.rem_size();
2692
2693        self.layout_engine
2694            .as_mut()
2695            .unwrap()
2696            .request_layout(style, rem_size, &cx.layout_id_buffer)
2697    }
2698
2699    /// Add a node to the layout tree for the current frame. Instead of taking a `Style` and children,
2700    /// this variant takes a function that is invoked during layout so you can use arbitrary logic to
2701    /// determine the element's size. One place this is used internally is when measuring text.
2702    ///
2703    /// The given closure is invoked at layout time with the known dimensions and available space and
2704    /// returns a `Size`.
2705    ///
2706    /// This method should only be called as part of the request_layout or prepaint phase of element drawing.
2707    pub fn request_measured_layout<
2708        F: FnMut(Size<Option<Pixels>>, Size<AvailableSpace>, &mut Window, &mut App) -> Size<Pixels>
2709            + 'static,
2710    >(
2711        &mut self,
2712        style: Style,
2713        measure: F,
2714    ) -> LayoutId {
2715        self.invalidator.debug_assert_prepaint();
2716
2717        let rem_size = self.rem_size();
2718        self.layout_engine
2719            .as_mut()
2720            .unwrap()
2721            .request_measured_layout(style, rem_size, measure)
2722    }
2723
2724    /// Compute the layout for the given id within the given available space.
2725    /// This method is called for its side effect, typically by the framework prior to painting.
2726    /// After calling it, you can request the bounds of the given layout node id or any descendant.
2727    ///
2728    /// This method should only be called as part of the prepaint phase of element drawing.
2729    pub fn compute_layout(
2730        &mut self,
2731        layout_id: LayoutId,
2732        available_space: Size<AvailableSpace>,
2733        cx: &mut App,
2734    ) {
2735        self.invalidator.debug_assert_prepaint();
2736
2737        let mut layout_engine = self.layout_engine.take().unwrap();
2738        layout_engine.compute_layout(layout_id, available_space, self, cx);
2739        self.layout_engine = Some(layout_engine);
2740    }
2741
2742    /// Obtain the bounds computed for the given LayoutId relative to the window. This method will usually be invoked by
2743    /// GPUI itself automatically in order to pass your element its `Bounds` automatically.
2744    ///
2745    /// This method should only be called as part of element drawing.
2746    pub fn layout_bounds(&mut self, layout_id: LayoutId) -> Bounds<Pixels> {
2747        self.invalidator.debug_assert_prepaint();
2748
2749        let mut bounds = self
2750            .layout_engine
2751            .as_mut()
2752            .unwrap()
2753            .layout_bounds(layout_id)
2754            .map(Into::into);
2755        bounds.origin += self.element_offset();
2756        bounds
2757    }
2758
2759    /// This method should be called during `prepaint`. You can use
2760    /// the returned [Hitbox] during `paint` or in an event handler
2761    /// to determine whether the inserted hitbox was the topmost.
2762    ///
2763    /// This method should only be called as part of the prepaint phase of element drawing.
2764    pub fn insert_hitbox(&mut self, bounds: Bounds<Pixels>, opaque: bool) -> Hitbox {
2765        self.invalidator.debug_assert_prepaint();
2766
2767        let content_mask = self.content_mask();
2768        let id = self.next_hitbox_id;
2769        self.next_hitbox_id.0 += 1;
2770        let hitbox = Hitbox {
2771            id,
2772            bounds,
2773            content_mask,
2774            opaque,
2775        };
2776        self.next_frame.hitboxes.push(hitbox.clone());
2777        hitbox
2778    }
2779
2780    /// Sets the key context for the current element. This context will be used to translate
2781    /// keybindings into actions.
2782    ///
2783    /// This method should only be called as part of the paint phase of element drawing.
2784    pub fn set_key_context(&mut self, context: KeyContext) {
2785        self.invalidator.debug_assert_paint();
2786        self.next_frame.dispatch_tree.set_key_context(context);
2787    }
2788
2789    /// Sets the focus handle for the current element. This handle will be used to manage focus state
2790    /// and keyboard event dispatch for the element.
2791    ///
2792    /// This method should only be called as part of the prepaint phase of element drawing.
2793    pub fn set_focus_handle(&mut self, focus_handle: &FocusHandle, _: &App) {
2794        self.invalidator.debug_assert_prepaint();
2795        if focus_handle.is_focused(self) {
2796            self.next_frame.focus = Some(focus_handle.id);
2797        }
2798        self.next_frame.dispatch_tree.set_focus_id(focus_handle.id);
2799    }
2800
2801    /// Sets the view id for the current element, which will be used to manage view caching.
2802    ///
2803    /// This method should only be called as part of element prepaint. We plan on removing this
2804    /// method eventually when we solve some issues that require us to construct editor elements
2805    /// directly instead of always using editors via views.
2806    pub fn set_view_id(&mut self, view_id: EntityId) {
2807        self.invalidator.debug_assert_prepaint();
2808        self.next_frame.dispatch_tree.set_view_id(view_id);
2809    }
2810
2811    /// Get the entity ID for the currently rendering view
2812    pub fn current_view(&self) -> EntityId {
2813        self.invalidator.debug_assert_paint_or_prepaint();
2814        self.rendered_entity_stack.last().copied().unwrap()
2815    }
2816
2817    pub(crate) fn with_rendered_view<R>(
2818        &mut self,
2819        id: EntityId,
2820        f: impl FnOnce(&mut Self) -> R,
2821    ) -> R {
2822        self.rendered_entity_stack.push(id);
2823        let result = f(self);
2824        self.rendered_entity_stack.pop();
2825        result
2826    }
2827
2828    /// Sets an input handler, such as [`ElementInputHandler`][element_input_handler], which interfaces with the
2829    /// platform to receive textual input with proper integration with concerns such
2830    /// as IME interactions. This handler will be active for the upcoming frame until the following frame is
2831    /// rendered.
2832    ///
2833    /// This method should only be called as part of the paint phase of element drawing.
2834    ///
2835    /// [element_input_handler]: crate::ElementInputHandler
2836    pub fn handle_input(
2837        &mut self,
2838        focus_handle: &FocusHandle,
2839        input_handler: impl InputHandler,
2840        cx: &App,
2841    ) {
2842        self.invalidator.debug_assert_paint();
2843
2844        if focus_handle.is_focused(self) {
2845            let cx = self.to_async(cx);
2846            self.next_frame
2847                .input_handlers
2848                .push(Some(PlatformInputHandler::new(cx, Box::new(input_handler))));
2849        }
2850    }
2851
2852    /// Register a mouse event listener on the window for the next frame. The type of event
2853    /// is determined by the first parameter of the given listener. When the next frame is rendered
2854    /// the listener will be cleared.
2855    ///
2856    /// This method should only be called as part of the paint phase of element drawing.
2857    pub fn on_mouse_event<Event: MouseEvent>(
2858        &mut self,
2859        mut handler: impl FnMut(&Event, DispatchPhase, &mut Window, &mut App) + 'static,
2860    ) {
2861        self.invalidator.debug_assert_paint();
2862
2863        self.next_frame.mouse_listeners.push(Some(Box::new(
2864            move |event: &dyn Any, phase: DispatchPhase, window: &mut Window, cx: &mut App| {
2865                if let Some(event) = event.downcast_ref() {
2866                    handler(event, phase, window, cx)
2867                }
2868            },
2869        )));
2870    }
2871
2872    /// Register a key event listener on the window for the next frame. The type of event
2873    /// is determined by the first parameter of the given listener. When the next frame is rendered
2874    /// the listener will be cleared.
2875    ///
2876    /// This is a fairly low-level method, so prefer using event handlers on elements unless you have
2877    /// a specific need to register a global listener.
2878    ///
2879    /// This method should only be called as part of the paint phase of element drawing.
2880    pub fn on_key_event<Event: KeyEvent>(
2881        &mut self,
2882        listener: impl Fn(&Event, DispatchPhase, &mut Window, &mut App) + 'static,
2883    ) {
2884        self.invalidator.debug_assert_paint();
2885
2886        self.next_frame.dispatch_tree.on_key_event(Rc::new(
2887            move |event: &dyn Any, phase, window: &mut Window, cx: &mut App| {
2888                if let Some(event) = event.downcast_ref::<Event>() {
2889                    listener(event, phase, window, cx)
2890                }
2891            },
2892        ));
2893    }
2894
2895    /// Register a modifiers changed event listener on the window for the next frame.
2896    ///
2897    /// This is a fairly low-level method, so prefer using event handlers on elements unless you have
2898    /// a specific need to register a global listener.
2899    ///
2900    /// This method should only be called as part of the paint phase of element drawing.
2901    pub fn on_modifiers_changed(
2902        &mut self,
2903        listener: impl Fn(&ModifiersChangedEvent, &mut Window, &mut App) + 'static,
2904    ) {
2905        self.invalidator.debug_assert_paint();
2906
2907        self.next_frame.dispatch_tree.on_modifiers_changed(Rc::new(
2908            move |event: &ModifiersChangedEvent, window: &mut Window, cx: &mut App| {
2909                listener(event, window, cx)
2910            },
2911        ));
2912    }
2913
2914    /// Register a listener to be called when the given focus handle or one of its descendants receives focus.
2915    /// This does not fire if the given focus handle - or one of its descendants - was previously focused.
2916    /// Returns a subscription and persists until the subscription is dropped.
2917    pub fn on_focus_in(
2918        &mut self,
2919        handle: &FocusHandle,
2920        cx: &mut App,
2921        mut listener: impl FnMut(&mut Window, &mut App) + 'static,
2922    ) -> Subscription {
2923        let focus_id = handle.id;
2924        let (subscription, activate) =
2925            self.new_focus_listener(Box::new(move |event, window, cx| {
2926                if event.is_focus_in(focus_id) {
2927                    listener(window, cx);
2928                }
2929                true
2930            }));
2931        cx.defer(move |_| activate());
2932        subscription
2933    }
2934
2935    /// Register a listener to be called when the given focus handle or one of its descendants loses focus.
2936    /// Returns a subscription and persists until the subscription is dropped.
2937    pub fn on_focus_out(
2938        &mut self,
2939        handle: &FocusHandle,
2940        cx: &mut App,
2941        mut listener: impl FnMut(FocusOutEvent, &mut Window, &mut App) + 'static,
2942    ) -> Subscription {
2943        let focus_id = handle.id;
2944        let (subscription, activate) =
2945            self.new_focus_listener(Box::new(move |event, window, cx| {
2946                if let Some(blurred_id) = event.previous_focus_path.last().copied() {
2947                    if event.is_focus_out(focus_id) {
2948                        let event = FocusOutEvent {
2949                            blurred: WeakFocusHandle {
2950                                id: blurred_id,
2951                                handles: Arc::downgrade(&cx.focus_handles),
2952                            },
2953                        };
2954                        listener(event, window, cx)
2955                    }
2956                }
2957                true
2958            }));
2959        cx.defer(move |_| activate());
2960        subscription
2961    }
2962
2963    fn reset_cursor_style(&self, cx: &mut App) {
2964        // Set the cursor only if we're the active window.
2965        if self.is_window_hovered() {
2966            let style = self
2967                .rendered_frame
2968                .cursor_styles
2969                .iter()
2970                .rev()
2971                .find(|request| request.hitbox_id.is_hovered(self))
2972                .map(|request| request.style)
2973                .unwrap_or(CursorStyle::Arrow);
2974            cx.platform.set_cursor_style(style);
2975        }
2976    }
2977
2978    /// Dispatch a given keystroke as though the user had typed it.
2979    /// You can create a keystroke with Keystroke::parse("").
2980    pub fn dispatch_keystroke(&mut self, keystroke: Keystroke, cx: &mut App) -> bool {
2981        let keystroke = keystroke.with_simulated_ime();
2982        let result = self.dispatch_event(
2983            PlatformInput::KeyDown(KeyDownEvent {
2984                keystroke: keystroke.clone(),
2985                is_held: false,
2986            }),
2987            cx,
2988        );
2989        if !result.propagate {
2990            return true;
2991        }
2992
2993        if let Some(input) = keystroke.key_char {
2994            if let Some(mut input_handler) = self.platform_window.take_input_handler() {
2995                input_handler.dispatch_input(&input, self, cx);
2996                self.platform_window.set_input_handler(input_handler);
2997                return true;
2998            }
2999        }
3000
3001        false
3002    }
3003
3004    /// Return a key binding string for an action, to display in the UI. Uses the highest precedence
3005    /// binding for the action (last binding added to the keymap).
3006    pub fn keystroke_text_for(&self, action: &dyn Action) -> String {
3007        self.bindings_for_action(action)
3008            .last()
3009            .map(|binding| {
3010                binding
3011                    .keystrokes()
3012                    .iter()
3013                    .map(ToString::to_string)
3014                    .collect::<Vec<_>>()
3015                    .join(" ")
3016            })
3017            .unwrap_or_else(|| action.name().to_string())
3018    }
3019
3020    /// Dispatch a mouse or keyboard event on the window.
3021    #[profiling::function]
3022    pub fn dispatch_event(&mut self, event: PlatformInput, cx: &mut App) -> DispatchEventResult {
3023        self.last_input_timestamp.set(Instant::now());
3024        // Handlers may set this to false by calling `stop_propagation`.
3025        cx.propagate_event = true;
3026        // Handlers may set this to true by calling `prevent_default`.
3027        self.default_prevented = false;
3028
3029        let event = match event {
3030            // Track the mouse position with our own state, since accessing the platform
3031            // API for the mouse position can only occur on the main thread.
3032            PlatformInput::MouseMove(mouse_move) => {
3033                self.mouse_position = mouse_move.position;
3034                self.modifiers = mouse_move.modifiers;
3035                PlatformInput::MouseMove(mouse_move)
3036            }
3037            PlatformInput::MouseDown(mouse_down) => {
3038                self.mouse_position = mouse_down.position;
3039                self.modifiers = mouse_down.modifiers;
3040                PlatformInput::MouseDown(mouse_down)
3041            }
3042            PlatformInput::MouseUp(mouse_up) => {
3043                self.mouse_position = mouse_up.position;
3044                self.modifiers = mouse_up.modifiers;
3045                PlatformInput::MouseUp(mouse_up)
3046            }
3047            PlatformInput::MouseExited(mouse_exited) => {
3048                self.modifiers = mouse_exited.modifiers;
3049                PlatformInput::MouseExited(mouse_exited)
3050            }
3051            PlatformInput::ModifiersChanged(modifiers_changed) => {
3052                self.modifiers = modifiers_changed.modifiers;
3053                PlatformInput::ModifiersChanged(modifiers_changed)
3054            }
3055            PlatformInput::ScrollWheel(scroll_wheel) => {
3056                self.mouse_position = scroll_wheel.position;
3057                self.modifiers = scroll_wheel.modifiers;
3058                PlatformInput::ScrollWheel(scroll_wheel)
3059            }
3060            // Translate dragging and dropping of external files from the operating system
3061            // to internal drag and drop events.
3062            PlatformInput::FileDrop(file_drop) => match file_drop {
3063                FileDropEvent::Entered { position, paths } => {
3064                    self.mouse_position = position;
3065                    if cx.active_drag.is_none() {
3066                        cx.active_drag = Some(AnyDrag {
3067                            value: Arc::new(paths.clone()),
3068                            view: cx.new(|_| paths).into(),
3069                            cursor_offset: position,
3070                        });
3071                    }
3072                    PlatformInput::MouseMove(MouseMoveEvent {
3073                        position,
3074                        pressed_button: Some(MouseButton::Left),
3075                        modifiers: Modifiers::default(),
3076                    })
3077                }
3078                FileDropEvent::Pending { position } => {
3079                    self.mouse_position = position;
3080                    PlatformInput::MouseMove(MouseMoveEvent {
3081                        position,
3082                        pressed_button: Some(MouseButton::Left),
3083                        modifiers: Modifiers::default(),
3084                    })
3085                }
3086                FileDropEvent::Submit { position } => {
3087                    cx.activate(true);
3088                    self.mouse_position = position;
3089                    PlatformInput::MouseUp(MouseUpEvent {
3090                        button: MouseButton::Left,
3091                        position,
3092                        modifiers: Modifiers::default(),
3093                        click_count: 1,
3094                    })
3095                }
3096                FileDropEvent::Exited => {
3097                    cx.active_drag.take();
3098                    PlatformInput::FileDrop(FileDropEvent::Exited)
3099                }
3100            },
3101            PlatformInput::KeyDown(_) | PlatformInput::KeyUp(_) => event,
3102        };
3103
3104        if let Some(any_mouse_event) = event.mouse_event() {
3105            self.dispatch_mouse_event(any_mouse_event, cx);
3106        } else if let Some(any_key_event) = event.keyboard_event() {
3107            self.dispatch_key_event(any_key_event, cx);
3108        }
3109
3110        DispatchEventResult {
3111            propagate: cx.propagate_event,
3112            default_prevented: self.default_prevented,
3113        }
3114    }
3115
3116    fn dispatch_mouse_event(&mut self, event: &dyn Any, cx: &mut App) {
3117        let hit_test = self.rendered_frame.hit_test(self.mouse_position());
3118        if hit_test != self.mouse_hit_test {
3119            self.mouse_hit_test = hit_test;
3120            self.reset_cursor_style(cx);
3121        }
3122
3123        let mut mouse_listeners = mem::take(&mut self.rendered_frame.mouse_listeners);
3124
3125        // Capture phase, events bubble from back to front. Handlers for this phase are used for
3126        // special purposes, such as detecting events outside of a given Bounds.
3127        for listener in &mut mouse_listeners {
3128            let listener = listener.as_mut().unwrap();
3129            listener(event, DispatchPhase::Capture, self, cx);
3130            if !cx.propagate_event {
3131                break;
3132            }
3133        }
3134
3135        // Bubble phase, where most normal handlers do their work.
3136        if cx.propagate_event {
3137            for listener in mouse_listeners.iter_mut().rev() {
3138                let listener = listener.as_mut().unwrap();
3139                listener(event, DispatchPhase::Bubble, self, cx);
3140                if !cx.propagate_event {
3141                    break;
3142                }
3143            }
3144        }
3145
3146        self.rendered_frame.mouse_listeners = mouse_listeners;
3147
3148        if cx.has_active_drag() {
3149            if event.is::<MouseMoveEvent>() {
3150                // If this was a mouse move event, redraw the window so that the
3151                // active drag can follow the mouse cursor.
3152                self.refresh();
3153            } else if event.is::<MouseUpEvent>() {
3154                // If this was a mouse up event, cancel the active drag and redraw
3155                // the window.
3156                cx.active_drag = None;
3157                self.refresh();
3158            }
3159        }
3160    }
3161
3162    fn dispatch_key_event(&mut self, event: &dyn Any, cx: &mut App) {
3163        if self.invalidator.is_dirty() {
3164            self.draw(cx);
3165        }
3166
3167        let node_id = self
3168            .focus
3169            .and_then(|focus_id| {
3170                self.rendered_frame
3171                    .dispatch_tree
3172                    .focusable_node_id(focus_id)
3173            })
3174            .unwrap_or_else(|| self.rendered_frame.dispatch_tree.root_node_id());
3175
3176        let dispatch_path = self.rendered_frame.dispatch_tree.dispatch_path(node_id);
3177
3178        let mut keystroke: Option<Keystroke> = None;
3179
3180        if let Some(event) = event.downcast_ref::<ModifiersChangedEvent>() {
3181            if event.modifiers.number_of_modifiers() == 0
3182                && self.pending_modifier.modifiers.number_of_modifiers() == 1
3183                && !self.pending_modifier.saw_keystroke
3184            {
3185                let key = match self.pending_modifier.modifiers {
3186                    modifiers if modifiers.shift => Some("shift"),
3187                    modifiers if modifiers.control => Some("control"),
3188                    modifiers if modifiers.alt => Some("alt"),
3189                    modifiers if modifiers.platform => Some("platform"),
3190                    modifiers if modifiers.function => Some("function"),
3191                    _ => None,
3192                };
3193                if let Some(key) = key {
3194                    keystroke = Some(Keystroke {
3195                        key: key.to_string(),
3196                        key_char: None,
3197                        modifiers: Modifiers::default(),
3198                    });
3199                }
3200            }
3201
3202            if self.pending_modifier.modifiers.number_of_modifiers() == 0
3203                && event.modifiers.number_of_modifiers() == 1
3204            {
3205                self.pending_modifier.saw_keystroke = false
3206            }
3207            self.pending_modifier.modifiers = event.modifiers
3208        } else if let Some(key_down_event) = event.downcast_ref::<KeyDownEvent>() {
3209            self.pending_modifier.saw_keystroke = true;
3210            keystroke = Some(key_down_event.keystroke.clone());
3211        }
3212
3213        let Some(keystroke) = keystroke else {
3214            self.finish_dispatch_key_event(event, dispatch_path, cx);
3215            return;
3216        };
3217
3218        let mut currently_pending = self.pending_input.take().unwrap_or_default();
3219        if currently_pending.focus.is_some() && currently_pending.focus != self.focus {
3220            currently_pending = PendingInput::default();
3221        }
3222
3223        let match_result = self.rendered_frame.dispatch_tree.dispatch_key(
3224            currently_pending.keystrokes,
3225            keystroke,
3226            &dispatch_path,
3227        );
3228        if !match_result.to_replay.is_empty() {
3229            self.replay_pending_input(match_result.to_replay, cx)
3230        }
3231
3232        if !match_result.pending.is_empty() {
3233            currently_pending.keystrokes = match_result.pending;
3234            currently_pending.focus = self.focus;
3235            currently_pending.timer = Some(self.spawn(cx, |mut cx| async move {
3236                cx.background_executor.timer(Duration::from_secs(1)).await;
3237                cx.update(move |window, cx| {
3238                    let Some(currently_pending) = window
3239                        .pending_input
3240                        .take()
3241                        .filter(|pending| pending.focus == window.focus)
3242                    else {
3243                        return;
3244                    };
3245
3246                    let dispatch_path = window.rendered_frame.dispatch_tree.dispatch_path(node_id);
3247
3248                    let to_replay = window
3249                        .rendered_frame
3250                        .dispatch_tree
3251                        .flush_dispatch(currently_pending.keystrokes, &dispatch_path);
3252
3253                    window.replay_pending_input(to_replay, cx)
3254                })
3255                .log_err();
3256            }));
3257            self.pending_input = Some(currently_pending);
3258            self.pending_input_changed(cx);
3259            cx.propagate_event = false;
3260            return;
3261        }
3262
3263        cx.propagate_event = true;
3264        for binding in match_result.bindings {
3265            self.dispatch_action_on_node(node_id, binding.action.as_ref(), cx);
3266            if !cx.propagate_event {
3267                self.dispatch_keystroke_observers(event, Some(binding.action), cx);
3268                self.pending_input_changed(cx);
3269                return;
3270            }
3271        }
3272
3273        self.finish_dispatch_key_event(event, dispatch_path, cx);
3274        self.pending_input_changed(cx);
3275    }
3276
3277    fn finish_dispatch_key_event(
3278        &mut self,
3279        event: &dyn Any,
3280        dispatch_path: SmallVec<[DispatchNodeId; 32]>,
3281        cx: &mut App,
3282    ) {
3283        self.dispatch_key_down_up_event(event, &dispatch_path, cx);
3284        if !cx.propagate_event {
3285            return;
3286        }
3287
3288        self.dispatch_modifiers_changed_event(event, &dispatch_path, cx);
3289        if !cx.propagate_event {
3290            return;
3291        }
3292
3293        self.dispatch_keystroke_observers(event, None, cx);
3294    }
3295
3296    fn pending_input_changed(&mut self, cx: &mut App) {
3297        self.pending_input_observers
3298            .clone()
3299            .retain(&(), |callback| callback(self, cx));
3300    }
3301
3302    fn dispatch_key_down_up_event(
3303        &mut self,
3304        event: &dyn Any,
3305        dispatch_path: &SmallVec<[DispatchNodeId; 32]>,
3306        cx: &mut App,
3307    ) {
3308        // Capture phase
3309        for node_id in dispatch_path {
3310            let node = self.rendered_frame.dispatch_tree.node(*node_id);
3311
3312            for key_listener in node.key_listeners.clone() {
3313                key_listener(event, DispatchPhase::Capture, self, cx);
3314                if !cx.propagate_event {
3315                    return;
3316                }
3317            }
3318        }
3319
3320        // Bubble phase
3321        for node_id in dispatch_path.iter().rev() {
3322            // Handle low level key events
3323            let node = self.rendered_frame.dispatch_tree.node(*node_id);
3324            for key_listener in node.key_listeners.clone() {
3325                key_listener(event, DispatchPhase::Bubble, self, cx);
3326                if !cx.propagate_event {
3327                    return;
3328                }
3329            }
3330        }
3331    }
3332
3333    fn dispatch_modifiers_changed_event(
3334        &mut self,
3335        event: &dyn Any,
3336        dispatch_path: &SmallVec<[DispatchNodeId; 32]>,
3337        cx: &mut App,
3338    ) {
3339        let Some(event) = event.downcast_ref::<ModifiersChangedEvent>() else {
3340            return;
3341        };
3342        for node_id in dispatch_path.iter().rev() {
3343            let node = self.rendered_frame.dispatch_tree.node(*node_id);
3344            for listener in node.modifiers_changed_listeners.clone() {
3345                listener(event, self, cx);
3346                if !cx.propagate_event {
3347                    return;
3348                }
3349            }
3350        }
3351    }
3352
3353    /// Determine whether a potential multi-stroke key binding is in progress on this window.
3354    pub fn has_pending_keystrokes(&self) -> bool {
3355        self.pending_input.is_some()
3356    }
3357
3358    pub(crate) fn clear_pending_keystrokes(&mut self) {
3359        self.pending_input.take();
3360    }
3361
3362    /// Returns the currently pending input keystrokes that might result in a multi-stroke key binding.
3363    pub fn pending_input_keystrokes(&self) -> Option<&[Keystroke]> {
3364        self.pending_input
3365            .as_ref()
3366            .map(|pending_input| pending_input.keystrokes.as_slice())
3367    }
3368
3369    fn replay_pending_input(&mut self, replays: SmallVec<[Replay; 1]>, cx: &mut App) {
3370        let node_id = self
3371            .focus
3372            .and_then(|focus_id| {
3373                self.rendered_frame
3374                    .dispatch_tree
3375                    .focusable_node_id(focus_id)
3376            })
3377            .unwrap_or_else(|| self.rendered_frame.dispatch_tree.root_node_id());
3378
3379        let dispatch_path = self.rendered_frame.dispatch_tree.dispatch_path(node_id);
3380
3381        'replay: for replay in replays {
3382            let event = KeyDownEvent {
3383                keystroke: replay.keystroke.clone(),
3384                is_held: false,
3385            };
3386
3387            cx.propagate_event = true;
3388            for binding in replay.bindings {
3389                self.dispatch_action_on_node(node_id, binding.action.as_ref(), cx);
3390                if !cx.propagate_event {
3391                    self.dispatch_keystroke_observers(&event, Some(binding.action), cx);
3392                    continue 'replay;
3393                }
3394            }
3395
3396            self.dispatch_key_down_up_event(&event, &dispatch_path, cx);
3397            if !cx.propagate_event {
3398                continue 'replay;
3399            }
3400            if let Some(input) = replay.keystroke.key_char.as_ref().cloned() {
3401                if let Some(mut input_handler) = self.platform_window.take_input_handler() {
3402                    input_handler.dispatch_input(&input, self, cx);
3403                    self.platform_window.set_input_handler(input_handler)
3404                }
3405            }
3406        }
3407    }
3408
3409    fn dispatch_action_on_node(
3410        &mut self,
3411        node_id: DispatchNodeId,
3412        action: &dyn Action,
3413        cx: &mut App,
3414    ) {
3415        let dispatch_path = self.rendered_frame.dispatch_tree.dispatch_path(node_id);
3416
3417        // Capture phase for global actions.
3418        cx.propagate_event = true;
3419        if let Some(mut global_listeners) = cx
3420            .global_action_listeners
3421            .remove(&action.as_any().type_id())
3422        {
3423            for listener in &global_listeners {
3424                listener(action.as_any(), DispatchPhase::Capture, cx);
3425                if !cx.propagate_event {
3426                    break;
3427                }
3428            }
3429
3430            global_listeners.extend(
3431                cx.global_action_listeners
3432                    .remove(&action.as_any().type_id())
3433                    .unwrap_or_default(),
3434            );
3435
3436            cx.global_action_listeners
3437                .insert(action.as_any().type_id(), global_listeners);
3438        }
3439
3440        if !cx.propagate_event {
3441            return;
3442        }
3443
3444        // Capture phase for window actions.
3445        for node_id in &dispatch_path {
3446            let node = self.rendered_frame.dispatch_tree.node(*node_id);
3447            for DispatchActionListener {
3448                action_type,
3449                listener,
3450            } in node.action_listeners.clone()
3451            {
3452                let any_action = action.as_any();
3453                if action_type == any_action.type_id() {
3454                    listener(any_action, DispatchPhase::Capture, self, cx);
3455
3456                    if !cx.propagate_event {
3457                        return;
3458                    }
3459                }
3460            }
3461        }
3462
3463        // Bubble phase for window actions.
3464        for node_id in dispatch_path.iter().rev() {
3465            let node = self.rendered_frame.dispatch_tree.node(*node_id);
3466            for DispatchActionListener {
3467                action_type,
3468                listener,
3469            } in node.action_listeners.clone()
3470            {
3471                let any_action = action.as_any();
3472                if action_type == any_action.type_id() {
3473                    cx.propagate_event = false; // Actions stop propagation by default during the bubble phase
3474                    listener(any_action, DispatchPhase::Bubble, self, cx);
3475
3476                    if !cx.propagate_event {
3477                        return;
3478                    }
3479                }
3480            }
3481        }
3482
3483        // Bubble phase for global actions.
3484        if let Some(mut global_listeners) = cx
3485            .global_action_listeners
3486            .remove(&action.as_any().type_id())
3487        {
3488            for listener in global_listeners.iter().rev() {
3489                cx.propagate_event = false; // Actions stop propagation by default during the bubble phase
3490
3491                listener(action.as_any(), DispatchPhase::Bubble, cx);
3492                if !cx.propagate_event {
3493                    break;
3494                }
3495            }
3496
3497            global_listeners.extend(
3498                cx.global_action_listeners
3499                    .remove(&action.as_any().type_id())
3500                    .unwrap_or_default(),
3501            );
3502
3503            cx.global_action_listeners
3504                .insert(action.as_any().type_id(), global_listeners);
3505        }
3506    }
3507
3508    /// Register the given handler to be invoked whenever the global of the given type
3509    /// is updated.
3510    pub fn observe_global<G: Global>(
3511        &mut self,
3512        cx: &mut App,
3513        f: impl Fn(&mut Window, &mut App) + 'static,
3514    ) -> Subscription {
3515        let window_handle = self.handle;
3516        let (subscription, activate) = cx.global_observers.insert(
3517            TypeId::of::<G>(),
3518            Box::new(move |cx| {
3519                window_handle
3520                    .update(cx, |_, window, cx| f(window, cx))
3521                    .is_ok()
3522            }),
3523        );
3524        cx.defer(move |_| activate());
3525        subscription
3526    }
3527
3528    /// Focus the current window and bring it to the foreground at the platform level.
3529    pub fn activate_window(&self) {
3530        self.platform_window.activate();
3531    }
3532
3533    /// Minimize the current window at the platform level.
3534    pub fn minimize_window(&self) {
3535        self.platform_window.minimize();
3536    }
3537
3538    /// Toggle full screen status on the current window at the platform level.
3539    pub fn toggle_fullscreen(&self) {
3540        self.platform_window.toggle_fullscreen();
3541    }
3542
3543    /// Updates the IME panel position suggestions for languages like japanese, chinese.
3544    pub fn invalidate_character_coordinates(&self) {
3545        self.on_next_frame(|window, cx| {
3546            if let Some(mut input_handler) = window.platform_window.take_input_handler() {
3547                if let Some(bounds) = input_handler.selected_bounds(window, cx) {
3548                    window
3549                        .platform_window
3550                        .update_ime_position(bounds.scale(window.scale_factor()));
3551                }
3552                window.platform_window.set_input_handler(input_handler);
3553            }
3554        });
3555    }
3556
3557    /// Present a platform dialog.
3558    /// The provided message will be presented, along with buttons for each answer.
3559    /// When a button is clicked, the returned Receiver will receive the index of the clicked button.
3560    pub fn prompt(
3561        &mut self,
3562        level: PromptLevel,
3563        message: &str,
3564        detail: Option<&str>,
3565        answers: &[&str],
3566        cx: &mut App,
3567    ) -> oneshot::Receiver<usize> {
3568        let prompt_builder = cx.prompt_builder.take();
3569        let Some(prompt_builder) = prompt_builder else {
3570            unreachable!("Re-entrant window prompting is not supported by GPUI");
3571        };
3572
3573        let receiver = match &prompt_builder {
3574            PromptBuilder::Default => self
3575                .platform_window
3576                .prompt(level, message, detail, answers)
3577                .unwrap_or_else(|| {
3578                    self.build_custom_prompt(&prompt_builder, level, message, detail, answers, cx)
3579                }),
3580            PromptBuilder::Custom(_) => {
3581                self.build_custom_prompt(&prompt_builder, level, message, detail, answers, cx)
3582            }
3583        };
3584
3585        cx.prompt_builder = Some(prompt_builder);
3586
3587        receiver
3588    }
3589
3590    fn build_custom_prompt(
3591        &mut self,
3592        prompt_builder: &PromptBuilder,
3593        level: PromptLevel,
3594        message: &str,
3595        detail: Option<&str>,
3596        answers: &[&str],
3597        cx: &mut App,
3598    ) -> oneshot::Receiver<usize> {
3599        let (sender, receiver) = oneshot::channel();
3600        let handle = PromptHandle::new(sender);
3601        let handle = (prompt_builder)(level, message, detail, answers, handle, self, cx);
3602        self.prompt = Some(handle);
3603        receiver
3604    }
3605
3606    /// Returns the current context stack.
3607    pub fn context_stack(&self) -> Vec<KeyContext> {
3608        let dispatch_tree = &self.rendered_frame.dispatch_tree;
3609        let node_id = self
3610            .focus
3611            .and_then(|focus_id| dispatch_tree.focusable_node_id(focus_id))
3612            .unwrap_or_else(|| dispatch_tree.root_node_id());
3613
3614        dispatch_tree
3615            .dispatch_path(node_id)
3616            .iter()
3617            .filter_map(move |&node_id| dispatch_tree.node(node_id).context.clone())
3618            .collect()
3619    }
3620
3621    /// Returns all available actions for the focused element.
3622    pub fn available_actions(&self, cx: &App) -> Vec<Box<dyn Action>> {
3623        let node_id = self
3624            .focus
3625            .and_then(|focus_id| {
3626                self.rendered_frame
3627                    .dispatch_tree
3628                    .focusable_node_id(focus_id)
3629            })
3630            .unwrap_or_else(|| self.rendered_frame.dispatch_tree.root_node_id());
3631
3632        let mut actions = self.rendered_frame.dispatch_tree.available_actions(node_id);
3633        for action_type in cx.global_action_listeners.keys() {
3634            if let Err(ix) = actions.binary_search_by_key(action_type, |a| a.as_any().type_id()) {
3635                let action = cx.actions.build_action_type(action_type).ok();
3636                if let Some(action) = action {
3637                    actions.insert(ix, action);
3638                }
3639            }
3640        }
3641        actions
3642    }
3643
3644    /// Returns key bindings that invoke an action on the currently focused element. Bindings are
3645    /// returned in the order they were added. For display, the last binding should take precedence.
3646    pub fn bindings_for_action(&self, action: &dyn Action) -> Vec<KeyBinding> {
3647        self.rendered_frame
3648            .dispatch_tree
3649            .bindings_for_action(action, &self.rendered_frame.dispatch_tree.context_stack)
3650    }
3651
3652    /// Returns any bindings that would invoke an action on the given focus handle if it were
3653    /// focused. Bindings are returned in the order they were added. For display, the last binding
3654    /// should take precedence.
3655    pub fn bindings_for_action_in(
3656        &self,
3657        action: &dyn Action,
3658        focus_handle: &FocusHandle,
3659    ) -> Vec<KeyBinding> {
3660        let dispatch_tree = &self.rendered_frame.dispatch_tree;
3661
3662        let Some(node_id) = dispatch_tree.focusable_node_id(focus_handle.id) else {
3663            return vec![];
3664        };
3665        let context_stack: Vec<_> = dispatch_tree
3666            .dispatch_path(node_id)
3667            .into_iter()
3668            .filter_map(|node_id| dispatch_tree.node(node_id).context.clone())
3669            .collect();
3670        dispatch_tree.bindings_for_action(action, &context_stack)
3671    }
3672
3673    /// Returns a generic event listener that invokes the given listener with the view and context associated with the given view handle.
3674    pub fn listener_for<V: Render, E>(
3675        &self,
3676        view: &Entity<V>,
3677        f: impl Fn(&mut V, &E, &mut Window, &mut Context<V>) + 'static,
3678    ) -> impl Fn(&E, &mut Window, &mut App) + 'static {
3679        let view = view.downgrade();
3680        move |e: &E, window: &mut Window, cx: &mut App| {
3681            view.update(cx, |view, cx| f(view, e, window, cx)).ok();
3682        }
3683    }
3684
3685    /// Returns a generic handler that invokes the given handler with the view and context associated with the given view handle.
3686    pub fn handler_for<V: Render>(
3687        &self,
3688        view: &Entity<V>,
3689        f: impl Fn(&mut V, &mut Window, &mut Context<V>) + 'static,
3690    ) -> impl Fn(&mut Window, &mut App) {
3691        let view = view.downgrade();
3692        move |window: &mut Window, cx: &mut App| {
3693            view.update(cx, |view, cx| f(view, window, cx)).ok();
3694        }
3695    }
3696
3697    /// Register a callback that can interrupt the closing of the current window based the returned boolean.
3698    /// If the callback returns false, the window won't be closed.
3699    pub fn on_window_should_close(
3700        &self,
3701        cx: &App,
3702        f: impl Fn(&mut Window, &mut App) -> bool + 'static,
3703    ) {
3704        let mut cx = self.to_async(cx);
3705        self.platform_window.on_should_close(Box::new(move || {
3706            cx.update(|window, cx| f(window, cx)).unwrap_or(true)
3707        }))
3708    }
3709
3710    /// Register an action listener on the window for the next frame. The type of action
3711    /// is determined by the first parameter of the given listener. When the next frame is rendered
3712    /// the listener will be cleared.
3713    ///
3714    /// This is a fairly low-level method, so prefer using action handlers on elements unless you have
3715    /// a specific need to register a global listener.
3716    pub fn on_action(
3717        &mut self,
3718        action_type: TypeId,
3719        listener: impl Fn(&dyn Any, DispatchPhase, &mut Window, &mut App) + 'static,
3720    ) {
3721        self.next_frame
3722            .dispatch_tree
3723            .on_action(action_type, Rc::new(listener));
3724    }
3725
3726    /// Read information about the GPU backing this window.
3727    /// Currently returns None on Mac and Windows.
3728    pub fn gpu_specs(&self) -> Option<GpuSpecs> {
3729        self.platform_window.gpu_specs()
3730    }
3731}
3732
3733// #[derive(Clone, Copy, Eq, PartialEq, Hash)]
3734slotmap::new_key_type! {
3735    /// A unique identifier for a window.
3736    pub struct WindowId;
3737}
3738
3739impl WindowId {
3740    /// Converts this window ID to a `u64`.
3741    pub fn as_u64(&self) -> u64 {
3742        self.0.as_ffi()
3743    }
3744}
3745
3746impl From<u64> for WindowId {
3747    fn from(value: u64) -> Self {
3748        WindowId(slotmap::KeyData::from_ffi(value))
3749    }
3750}
3751
3752/// A handle to a window with a specific root view type.
3753/// Note that this does not keep the window alive on its own.
3754#[derive(Deref, DerefMut)]
3755pub struct WindowHandle<V> {
3756    #[deref]
3757    #[deref_mut]
3758    pub(crate) any_handle: AnyWindowHandle,
3759    state_type: PhantomData<V>,
3760}
3761
3762impl<V: 'static + Render> WindowHandle<V> {
3763    /// Creates a new handle from a window ID.
3764    /// This does not check if the root type of the window is `V`.
3765    pub fn new(id: WindowId) -> Self {
3766        WindowHandle {
3767            any_handle: AnyWindowHandle {
3768                id,
3769                state_type: TypeId::of::<V>(),
3770            },
3771            state_type: PhantomData,
3772        }
3773    }
3774
3775    /// Get the root view out of this window.
3776    ///
3777    /// This will fail if the window is closed or if the root view's type does not match `V`.
3778    #[cfg(any(test, feature = "test-support"))]
3779    pub fn root<C>(&self, cx: &mut C) -> Result<Entity<V>>
3780    where
3781        C: AppContext,
3782    {
3783        crate::Flatten::flatten(cx.update_window(self.any_handle, |root_view, _, _| {
3784            root_view
3785                .downcast::<V>()
3786                .map_err(|_| anyhow!("the type of the window's root view has changed"))
3787        }))
3788    }
3789
3790    /// Updates the root view of this window.
3791    ///
3792    /// This will fail if the window has been closed or if the root view's type does not match
3793    pub fn update<C, R>(
3794        &self,
3795        cx: &mut C,
3796        update: impl FnOnce(&mut V, &mut Window, &mut Context<'_, V>) -> R,
3797    ) -> Result<R>
3798    where
3799        C: AppContext,
3800    {
3801        cx.update_window(self.any_handle, |root_view, window, cx| {
3802            let view = root_view
3803                .downcast::<V>()
3804                .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
3805
3806            Ok(view.update(cx, |view, cx| update(view, window, cx)))
3807        })?
3808    }
3809
3810    /// Read the root view out of this window.
3811    ///
3812    /// This will fail if the window is closed or if the root view's type does not match `V`.
3813    pub fn read<'a>(&self, cx: &'a App) -> Result<&'a V> {
3814        let x = cx
3815            .windows
3816            .get(self.id)
3817            .and_then(|window| {
3818                window
3819                    .as_ref()
3820                    .and_then(|window| window.root.clone())
3821                    .map(|root_view| root_view.downcast::<V>())
3822            })
3823            .ok_or_else(|| anyhow!("window not found"))?
3824            .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
3825
3826        Ok(x.read(cx))
3827    }
3828
3829    /// Read the root view out of this window, with a callback
3830    ///
3831    /// This will fail if the window is closed or if the root view's type does not match `V`.
3832    pub fn read_with<C, R>(&self, cx: &C, read_with: impl FnOnce(&V, &App) -> R) -> Result<R>
3833    where
3834        C: AppContext,
3835    {
3836        cx.read_window(self, |root_view, cx| read_with(root_view.read(cx), cx))
3837    }
3838
3839    /// Read the root view pointer off of this window.
3840    ///
3841    /// This will fail if the window is closed or if the root view's type does not match `V`.
3842    pub fn entity<C>(&self, cx: &C) -> Result<Entity<V>>
3843    where
3844        C: AppContext,
3845    {
3846        cx.read_window(self, |root_view, _cx| root_view.clone())
3847    }
3848
3849    /// Check if this window is 'active'.
3850    ///
3851    /// Will return `None` if the window is closed or currently
3852    /// borrowed.
3853    pub fn is_active(&self, cx: &mut App) -> Option<bool> {
3854        cx.update_window(self.any_handle, |_, window, _| window.is_window_active())
3855            .ok()
3856    }
3857}
3858
3859impl<V> Copy for WindowHandle<V> {}
3860
3861impl<V> Clone for WindowHandle<V> {
3862    fn clone(&self) -> Self {
3863        *self
3864    }
3865}
3866
3867impl<V> PartialEq for WindowHandle<V> {
3868    fn eq(&self, other: &Self) -> bool {
3869        self.any_handle == other.any_handle
3870    }
3871}
3872
3873impl<V> Eq for WindowHandle<V> {}
3874
3875impl<V> Hash for WindowHandle<V> {
3876    fn hash<H: Hasher>(&self, state: &mut H) {
3877        self.any_handle.hash(state);
3878    }
3879}
3880
3881impl<V: 'static> From<WindowHandle<V>> for AnyWindowHandle {
3882    fn from(val: WindowHandle<V>) -> Self {
3883        val.any_handle
3884    }
3885}
3886
3887unsafe impl<V> Send for WindowHandle<V> {}
3888unsafe impl<V> Sync for WindowHandle<V> {}
3889
3890/// A handle to a window with any root view type, which can be downcast to a window with a specific root view type.
3891#[derive(Copy, Clone, PartialEq, Eq, Hash)]
3892pub struct AnyWindowHandle {
3893    pub(crate) id: WindowId,
3894    state_type: TypeId,
3895}
3896
3897impl AnyWindowHandle {
3898    /// Get the ID of this window.
3899    pub fn window_id(&self) -> WindowId {
3900        self.id
3901    }
3902
3903    /// Attempt to convert this handle to a window handle with a specific root view type.
3904    /// If the types do not match, this will return `None`.
3905    pub fn downcast<T: 'static>(&self) -> Option<WindowHandle<T>> {
3906        if TypeId::of::<T>() == self.state_type {
3907            Some(WindowHandle {
3908                any_handle: *self,
3909                state_type: PhantomData,
3910            })
3911        } else {
3912            None
3913        }
3914    }
3915
3916    /// Updates the state of the root view of this window.
3917    ///
3918    /// This will fail if the window has been closed.
3919    pub fn update<C, R>(
3920        self,
3921        cx: &mut C,
3922        update: impl FnOnce(AnyView, &mut Window, &mut App) -> R,
3923    ) -> Result<R>
3924    where
3925        C: AppContext,
3926    {
3927        cx.update_window(self, update)
3928    }
3929
3930    /// Read the state of the root view of this window.
3931    ///
3932    /// This will fail if the window has been closed.
3933    pub fn read<T, C, R>(self, cx: &C, read: impl FnOnce(Entity<T>, &App) -> R) -> Result<R>
3934    where
3935        C: AppContext,
3936        T: 'static,
3937    {
3938        let view = self
3939            .downcast::<T>()
3940            .context("the type of the window's root view has changed")?;
3941
3942        cx.read_window(&view, read)
3943    }
3944}
3945
3946/// An identifier for an [`Element`](crate::Element).
3947///
3948/// Can be constructed with a string, a number, or both, as well
3949/// as other internal representations.
3950#[derive(Clone, Debug, Eq, PartialEq, Hash)]
3951pub enum ElementId {
3952    /// The ID of a View element
3953    View(EntityId),
3954    /// An integer ID.
3955    Integer(usize),
3956    /// A string based ID.
3957    Name(SharedString),
3958    /// A UUID.
3959    Uuid(Uuid),
3960    /// An ID that's equated with a focus handle.
3961    FocusHandle(FocusId),
3962    /// A combination of a name and an integer.
3963    NamedInteger(SharedString, usize),
3964    /// A path
3965    Path(Arc<std::path::Path>),
3966}
3967
3968impl Display for ElementId {
3969    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
3970        match self {
3971            ElementId::View(entity_id) => write!(f, "view-{}", entity_id)?,
3972            ElementId::Integer(ix) => write!(f, "{}", ix)?,
3973            ElementId::Name(name) => write!(f, "{}", name)?,
3974            ElementId::FocusHandle(_) => write!(f, "FocusHandle")?,
3975            ElementId::NamedInteger(s, i) => write!(f, "{}-{}", s, i)?,
3976            ElementId::Uuid(uuid) => write!(f, "{}", uuid)?,
3977            ElementId::Path(path) => write!(f, "{}", path.display())?,
3978        }
3979
3980        Ok(())
3981    }
3982}
3983
3984impl TryInto<SharedString> for ElementId {
3985    type Error = anyhow::Error;
3986
3987    fn try_into(self) -> anyhow::Result<SharedString> {
3988        if let ElementId::Name(name) = self {
3989            Ok(name)
3990        } else {
3991            Err(anyhow!("element id is not string"))
3992        }
3993    }
3994}
3995
3996impl From<usize> for ElementId {
3997    fn from(id: usize) -> Self {
3998        ElementId::Integer(id)
3999    }
4000}
4001
4002impl From<i32> for ElementId {
4003    fn from(id: i32) -> Self {
4004        Self::Integer(id as usize)
4005    }
4006}
4007
4008impl From<SharedString> for ElementId {
4009    fn from(name: SharedString) -> Self {
4010        ElementId::Name(name)
4011    }
4012}
4013
4014impl From<Arc<std::path::Path>> for ElementId {
4015    fn from(path: Arc<std::path::Path>) -> Self {
4016        ElementId::Path(path)
4017    }
4018}
4019
4020impl From<&'static str> for ElementId {
4021    fn from(name: &'static str) -> Self {
4022        ElementId::Name(name.into())
4023    }
4024}
4025
4026impl<'a> From<&'a FocusHandle> for ElementId {
4027    fn from(handle: &'a FocusHandle) -> Self {
4028        ElementId::FocusHandle(handle.id)
4029    }
4030}
4031
4032impl From<(&'static str, EntityId)> for ElementId {
4033    fn from((name, id): (&'static str, EntityId)) -> Self {
4034        ElementId::NamedInteger(name.into(), id.as_u64() as usize)
4035    }
4036}
4037
4038impl From<(&'static str, usize)> for ElementId {
4039    fn from((name, id): (&'static str, usize)) -> Self {
4040        ElementId::NamedInteger(name.into(), id)
4041    }
4042}
4043
4044impl From<(SharedString, usize)> for ElementId {
4045    fn from((name, id): (SharedString, usize)) -> Self {
4046        ElementId::NamedInteger(name, id)
4047    }
4048}
4049
4050impl From<(&'static str, u64)> for ElementId {
4051    fn from((name, id): (&'static str, u64)) -> Self {
4052        ElementId::NamedInteger(name.into(), id as usize)
4053    }
4054}
4055
4056impl From<Uuid> for ElementId {
4057    fn from(value: Uuid) -> Self {
4058        Self::Uuid(value)
4059    }
4060}
4061
4062impl From<(&'static str, u32)> for ElementId {
4063    fn from((name, id): (&'static str, u32)) -> Self {
4064        ElementId::NamedInteger(name.into(), id as usize)
4065    }
4066}
4067
4068/// A rectangle to be rendered in the window at the given position and size.
4069/// Passed as an argument [`Window::paint_quad`].
4070#[derive(Clone)]
4071pub struct PaintQuad {
4072    /// The bounds of the quad within the window.
4073    pub bounds: Bounds<Pixels>,
4074    /// The radii of the quad's corners.
4075    pub corner_radii: Corners<Pixels>,
4076    /// The background color of the quad.
4077    pub background: Background,
4078    /// The widths of the quad's borders.
4079    pub border_widths: Edges<Pixels>,
4080    /// The color of the quad's borders.
4081    pub border_color: Hsla,
4082}
4083
4084impl PaintQuad {
4085    /// Sets the corner radii of the quad.
4086    pub fn corner_radii(self, corner_radii: impl Into<Corners<Pixels>>) -> Self {
4087        PaintQuad {
4088            corner_radii: corner_radii.into(),
4089            ..self
4090        }
4091    }
4092
4093    /// Sets the border widths of the quad.
4094    pub fn border_widths(self, border_widths: impl Into<Edges<Pixels>>) -> Self {
4095        PaintQuad {
4096            border_widths: border_widths.into(),
4097            ..self
4098        }
4099    }
4100
4101    /// Sets the border color of the quad.
4102    pub fn border_color(self, border_color: impl Into<Hsla>) -> Self {
4103        PaintQuad {
4104            border_color: border_color.into(),
4105            ..self
4106        }
4107    }
4108
4109    /// Sets the background color of the quad.
4110    pub fn background(self, background: impl Into<Background>) -> Self {
4111        PaintQuad {
4112            background: background.into(),
4113            ..self
4114        }
4115    }
4116}
4117
4118/// Creates a quad with the given parameters.
4119pub fn quad(
4120    bounds: Bounds<Pixels>,
4121    corner_radii: impl Into<Corners<Pixels>>,
4122    background: impl Into<Background>,
4123    border_widths: impl Into<Edges<Pixels>>,
4124    border_color: impl Into<Hsla>,
4125) -> PaintQuad {
4126    PaintQuad {
4127        bounds,
4128        corner_radii: corner_radii.into(),
4129        background: background.into(),
4130        border_widths: border_widths.into(),
4131        border_color: border_color.into(),
4132    }
4133}
4134
4135/// Creates a filled quad with the given bounds and background color.
4136pub fn fill(bounds: impl Into<Bounds<Pixels>>, background: impl Into<Background>) -> PaintQuad {
4137    PaintQuad {
4138        bounds: bounds.into(),
4139        corner_radii: (0.).into(),
4140        background: background.into(),
4141        border_widths: (0.).into(),
4142        border_color: transparent_black(),
4143    }
4144}
4145
4146/// Creates a rectangle outline with the given bounds, border color, and a 1px border width
4147pub fn outline(bounds: impl Into<Bounds<Pixels>>, border_color: impl Into<Hsla>) -> PaintQuad {
4148    PaintQuad {
4149        bounds: bounds.into(),
4150        corner_radii: (0.).into(),
4151        background: transparent_black().into(),
4152        border_widths: (1.).into(),
4153        border_color: border_color.into(),
4154    }
4155}