window.rs

   1use crate::{
   2    point, px, size, transparent_black, Action, AnyDrag, AnyView, AppContext, Arena,
   3    AsyncWindowContext, Bounds, Context, Corners, CursorStyle, DispatchActionListener,
   4    DispatchNodeId, DispatchTree, DisplayId, Edges, Effect, Entity, EntityId, EventEmitter,
   5    FileDropEvent, Flatten, Global, GlobalElementId, GlobalPixels, Hsla, KeyBinding, KeyDownEvent,
   6    KeyMatch, KeymatchResult, Keystroke, KeystrokeEvent, Model, ModelContext, Modifiers,
   7    ModifiersChangedEvent, MouseButton, MouseMoveEvent, MouseUpEvent, Pixels, PlatformAtlas,
   8    PlatformDisplay, PlatformInput, PlatformWindow, Point, PromptLevel, Render, ScaledPixels,
   9    SharedString, Size, SubscriberSet, Subscription, TaffyLayoutEngine, Task, TextStyle,
  10    TextStyleRefinement, View, VisualContext, WeakView, WindowAppearance, WindowOptions,
  11    WindowParams, WindowTextSystem,
  12};
  13use anyhow::{anyhow, Context as _, Result};
  14use collections::FxHashSet;
  15use derive_more::{Deref, DerefMut};
  16use futures::channel::oneshot;
  17use parking_lot::RwLock;
  18use refineable::Refineable;
  19use slotmap::SlotMap;
  20use smallvec::SmallVec;
  21use std::{
  22    any::{Any, TypeId},
  23    borrow::{Borrow, BorrowMut},
  24    cell::{Cell, RefCell},
  25    fmt::{Debug, Display},
  26    future::Future,
  27    hash::{Hash, Hasher},
  28    marker::PhantomData,
  29    mem,
  30    rc::Rc,
  31    sync::{
  32        atomic::{AtomicUsize, Ordering::SeqCst},
  33        Arc, Weak,
  34    },
  35    time::{Duration, Instant},
  36};
  37use util::{measure, ResultExt};
  38
  39mod element_cx;
  40mod prompts;
  41
  42pub use element_cx::*;
  43pub use prompts::*;
  44
  45/// Represents the two different phases when dispatching events.
  46#[derive(Default, Copy, Clone, Debug, Eq, PartialEq)]
  47pub enum DispatchPhase {
  48    /// After the capture phase comes the bubble phase, in which mouse event listeners are
  49    /// invoked front to back and keyboard event listeners are invoked from the focused element
  50    /// to the root of the element tree. This is the phase you'll most commonly want to use when
  51    /// registering event listeners.
  52    #[default]
  53    Bubble,
  54    /// During the initial capture phase, mouse event listeners are invoked back to front, and keyboard
  55    /// listeners are invoked from the root of the tree downward toward the focused element. This phase
  56    /// is used for special purposes such as clearing the "pressed" state for click events. If
  57    /// you stop event propagation during this phase, you need to know what you're doing. Handlers
  58    /// outside of the immediate region may rely on detecting non-local events during this phase.
  59    Capture,
  60}
  61
  62impl DispatchPhase {
  63    /// Returns true if this represents the "bubble" phase.
  64    pub fn bubble(self) -> bool {
  65        self == DispatchPhase::Bubble
  66    }
  67
  68    /// Returns true if this represents the "capture" phase.
  69    pub fn capture(self) -> bool {
  70        self == DispatchPhase::Capture
  71    }
  72}
  73
  74type AnyObserver = Box<dyn FnMut(&mut WindowContext) -> bool + 'static>;
  75
  76type AnyWindowFocusListener = Box<dyn FnMut(&FocusEvent, &mut WindowContext) -> bool + 'static>;
  77
  78struct FocusEvent {
  79    previous_focus_path: SmallVec<[FocusId; 8]>,
  80    current_focus_path: SmallVec<[FocusId; 8]>,
  81}
  82
  83slotmap::new_key_type! {
  84    /// A globally unique identifier for a focusable element.
  85    pub struct FocusId;
  86}
  87
  88thread_local! {
  89    pub(crate) static ELEMENT_ARENA: RefCell<Arena> = RefCell::new(Arena::new(8 * 1024 * 1024));
  90}
  91
  92impl FocusId {
  93    /// Obtains whether the element associated with this handle is currently focused.
  94    pub fn is_focused(&self, cx: &WindowContext) -> bool {
  95        cx.window.focus == Some(*self)
  96    }
  97
  98    /// Obtains whether the element associated with this handle contains the focused
  99    /// element or is itself focused.
 100    pub fn contains_focused(&self, cx: &WindowContext) -> bool {
 101        cx.focused()
 102            .map_or(false, |focused| self.contains(focused.id, cx))
 103    }
 104
 105    /// Obtains whether the element associated with this handle is contained within the
 106    /// focused element or is itself focused.
 107    pub fn within_focused(&self, cx: &WindowContext) -> bool {
 108        let focused = cx.focused();
 109        focused.map_or(false, |focused| focused.id.contains(*self, cx))
 110    }
 111
 112    /// Obtains whether this handle contains the given handle in the most recently rendered frame.
 113    pub(crate) fn contains(&self, other: Self, cx: &WindowContext) -> bool {
 114        cx.window
 115            .rendered_frame
 116            .dispatch_tree
 117            .focus_contains(*self, other)
 118    }
 119}
 120
 121/// A handle which can be used to track and manipulate the focused element in a window.
 122pub struct FocusHandle {
 123    pub(crate) id: FocusId,
 124    handles: Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>,
 125}
 126
 127impl std::fmt::Debug for FocusHandle {
 128    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 129        f.write_fmt(format_args!("FocusHandle({:?})", self.id))
 130    }
 131}
 132
 133impl FocusHandle {
 134    pub(crate) fn new(handles: &Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>) -> Self {
 135        let id = handles.write().insert(AtomicUsize::new(1));
 136        Self {
 137            id,
 138            handles: handles.clone(),
 139        }
 140    }
 141
 142    pub(crate) fn for_id(
 143        id: FocusId,
 144        handles: &Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>,
 145    ) -> Option<Self> {
 146        let lock = handles.read();
 147        let ref_count = lock.get(id)?;
 148        if ref_count.load(SeqCst) == 0 {
 149            None
 150        } else {
 151            ref_count.fetch_add(1, SeqCst);
 152            Some(Self {
 153                id,
 154                handles: handles.clone(),
 155            })
 156        }
 157    }
 158
 159    /// Converts this focus handle into a weak variant, which does not prevent it from being released.
 160    pub fn downgrade(&self) -> WeakFocusHandle {
 161        WeakFocusHandle {
 162            id: self.id,
 163            handles: Arc::downgrade(&self.handles),
 164        }
 165    }
 166
 167    /// Moves the focus to the element associated with this handle.
 168    pub fn focus(&self, cx: &mut WindowContext) {
 169        cx.focus(self)
 170    }
 171
 172    /// Obtains whether the element associated with this handle is currently focused.
 173    pub fn is_focused(&self, cx: &WindowContext) -> bool {
 174        self.id.is_focused(cx)
 175    }
 176
 177    /// Obtains whether the element associated with this handle contains the focused
 178    /// element or is itself focused.
 179    pub fn contains_focused(&self, cx: &WindowContext) -> bool {
 180        self.id.contains_focused(cx)
 181    }
 182
 183    /// Obtains whether the element associated with this handle is contained within the
 184    /// focused element or is itself focused.
 185    pub fn within_focused(&self, cx: &WindowContext) -> bool {
 186        self.id.within_focused(cx)
 187    }
 188
 189    /// Obtains whether this handle contains the given handle in the most recently rendered frame.
 190    pub fn contains(&self, other: &Self, cx: &WindowContext) -> bool {
 191        self.id.contains(other.id, cx)
 192    }
 193}
 194
 195impl Clone for FocusHandle {
 196    fn clone(&self) -> Self {
 197        Self::for_id(self.id, &self.handles).unwrap()
 198    }
 199}
 200
 201impl PartialEq for FocusHandle {
 202    fn eq(&self, other: &Self) -> bool {
 203        self.id == other.id
 204    }
 205}
 206
 207impl Eq for FocusHandle {}
 208
 209impl Drop for FocusHandle {
 210    fn drop(&mut self) {
 211        self.handles
 212            .read()
 213            .get(self.id)
 214            .unwrap()
 215            .fetch_sub(1, SeqCst);
 216    }
 217}
 218
 219/// A weak reference to a focus handle.
 220#[derive(Clone, Debug)]
 221pub struct WeakFocusHandle {
 222    pub(crate) id: FocusId,
 223    handles: Weak<RwLock<SlotMap<FocusId, AtomicUsize>>>,
 224}
 225
 226impl WeakFocusHandle {
 227    /// Attempts to upgrade the [WeakFocusHandle] to a [FocusHandle].
 228    pub fn upgrade(&self) -> Option<FocusHandle> {
 229        let handles = self.handles.upgrade()?;
 230        FocusHandle::for_id(self.id, &handles)
 231    }
 232}
 233
 234impl PartialEq for WeakFocusHandle {
 235    fn eq(&self, other: &WeakFocusHandle) -> bool {
 236        self.id == other.id
 237    }
 238}
 239
 240impl Eq for WeakFocusHandle {}
 241
 242impl PartialEq<FocusHandle> for WeakFocusHandle {
 243    fn eq(&self, other: &FocusHandle) -> bool {
 244        self.id == other.id
 245    }
 246}
 247
 248impl PartialEq<WeakFocusHandle> for FocusHandle {
 249    fn eq(&self, other: &WeakFocusHandle) -> bool {
 250        self.id == other.id
 251    }
 252}
 253
 254/// FocusableView allows users of your view to easily
 255/// focus it (using cx.focus_view(view))
 256pub trait FocusableView: 'static + Render {
 257    /// Returns the focus handle associated with this view.
 258    fn focus_handle(&self, cx: &AppContext) -> FocusHandle;
 259}
 260
 261/// ManagedView is a view (like a Modal, Popover, Menu, etc.)
 262/// where the lifecycle of the view is handled by another view.
 263pub trait ManagedView: FocusableView + EventEmitter<DismissEvent> {}
 264
 265impl<M: FocusableView + EventEmitter<DismissEvent>> ManagedView for M {}
 266
 267/// Emitted by implementers of [`ManagedView`] to indicate the view should be dismissed, such as when a view is presented as a modal.
 268pub struct DismissEvent;
 269
 270type FrameCallback = Box<dyn FnOnce(&mut WindowContext)>;
 271
 272// Holds the state for a specific window.
 273#[doc(hidden)]
 274pub struct Window {
 275    pub(crate) handle: AnyWindowHandle,
 276    pub(crate) removed: bool,
 277    pub(crate) platform_window: Box<dyn PlatformWindow>,
 278    display_id: DisplayId,
 279    sprite_atlas: Arc<dyn PlatformAtlas>,
 280    text_system: Arc<WindowTextSystem>,
 281    pub(crate) rem_size: Pixels,
 282    pub(crate) viewport_size: Size<Pixels>,
 283    layout_engine: Option<TaffyLayoutEngine>,
 284    pub(crate) root_view: Option<AnyView>,
 285    pub(crate) element_id_stack: GlobalElementId,
 286    pub(crate) text_style_stack: Vec<TextStyleRefinement>,
 287    pub(crate) rendered_frame: Frame,
 288    pub(crate) next_frame: Frame,
 289    pub(crate) next_hitbox_id: HitboxId,
 290    next_frame_callbacks: Rc<RefCell<Vec<FrameCallback>>>,
 291    pub(crate) dirty_views: FxHashSet<EntityId>,
 292    pub(crate) focus_handles: Arc<RwLock<SlotMap<FocusId, AtomicUsize>>>,
 293    focus_listeners: SubscriberSet<(), AnyWindowFocusListener>,
 294    focus_lost_listeners: SubscriberSet<(), AnyObserver>,
 295    default_prevented: bool,
 296    mouse_position: Point<Pixels>,
 297    mouse_hit_test: HitTest,
 298    modifiers: Modifiers,
 299    scale_factor: f32,
 300    bounds_observers: SubscriberSet<(), AnyObserver>,
 301    appearance: WindowAppearance,
 302    appearance_observers: SubscriberSet<(), AnyObserver>,
 303    active: Rc<Cell<bool>>,
 304    pub(crate) dirty: Rc<Cell<bool>>,
 305    pub(crate) needs_present: Rc<Cell<bool>>,
 306    pub(crate) last_input_timestamp: Rc<Cell<Instant>>,
 307    pub(crate) refreshing: bool,
 308    pub(crate) draw_phase: DrawPhase,
 309    activation_observers: SubscriberSet<(), AnyObserver>,
 310    pub(crate) focus: Option<FocusId>,
 311    focus_enabled: bool,
 312    pending_input: Option<PendingInput>,
 313    prompt: Option<RenderablePromptHandle>,
 314}
 315
 316#[derive(Clone, Copy, Debug, Eq, PartialEq)]
 317pub(crate) enum DrawPhase {
 318    None,
 319    Layout,
 320    Paint,
 321    Focus,
 322}
 323
 324#[derive(Default, Debug)]
 325struct PendingInput {
 326    keystrokes: SmallVec<[Keystroke; 1]>,
 327    bindings: SmallVec<[KeyBinding; 1]>,
 328    focus: Option<FocusId>,
 329    timer: Option<Task<()>>,
 330}
 331
 332impl PendingInput {
 333    fn input(&self) -> String {
 334        self.keystrokes
 335            .iter()
 336            .flat_map(|k| k.ime_key.clone())
 337            .collect::<Vec<String>>()
 338            .join("")
 339    }
 340
 341    fn used_by_binding(&self, binding: &KeyBinding) -> bool {
 342        if self.keystrokes.is_empty() {
 343            return true;
 344        }
 345        let keystroke = &self.keystrokes[0];
 346        for candidate in keystroke.match_candidates() {
 347            if binding.match_keystrokes(&[candidate]) == KeyMatch::Pending {
 348                return true;
 349            }
 350        }
 351        false
 352    }
 353}
 354
 355pub(crate) struct ElementStateBox {
 356    pub(crate) inner: Box<dyn Any>,
 357    #[cfg(debug_assertions)]
 358    pub(crate) type_name: &'static str,
 359}
 360
 361fn default_bounds(cx: &mut AppContext) -> Bounds<GlobalPixels> {
 362    const DEFAULT_WINDOW_SIZE: Size<GlobalPixels> = size(GlobalPixels(1024.0), GlobalPixels(700.0));
 363    const DEFAULT_WINDOW_OFFSET: Point<GlobalPixels> = point(GlobalPixels(0.0), GlobalPixels(35.0));
 364
 365    cx.active_window()
 366        .and_then(|w| w.update(cx, |_, cx| cx.window_bounds()).ok())
 367        .map(|bounds| bounds.map_origin(|origin| origin + DEFAULT_WINDOW_OFFSET))
 368        .unwrap_or_else(|| {
 369            cx.primary_display()
 370                .map(|display| {
 371                    let center = display.bounds().center();
 372                    let offset = DEFAULT_WINDOW_SIZE / 2.0;
 373                    let origin = point(center.x - offset.width, center.y - offset.height);
 374                    Bounds::new(origin, DEFAULT_WINDOW_SIZE)
 375                })
 376                .unwrap_or_else(|| {
 377                    Bounds::new(
 378                        point(GlobalPixels(0.0), GlobalPixels(0.0)),
 379                        DEFAULT_WINDOW_SIZE,
 380                    )
 381                })
 382        })
 383}
 384
 385impl Window {
 386    pub(crate) fn new(
 387        handle: AnyWindowHandle,
 388        options: WindowOptions,
 389        cx: &mut AppContext,
 390    ) -> Self {
 391        let WindowOptions {
 392            bounds,
 393            titlebar,
 394            focus,
 395            show,
 396            kind,
 397            is_movable,
 398            display_id,
 399            fullscreen,
 400        } = options;
 401
 402        let bounds = bounds.unwrap_or_else(|| default_bounds(cx));
 403        let platform_window = cx.platform.open_window(
 404            handle,
 405            WindowParams {
 406                bounds,
 407                titlebar,
 408                kind,
 409                is_movable,
 410                focus,
 411                show,
 412                display_id,
 413            },
 414        );
 415        let display_id = platform_window.display().id();
 416        let sprite_atlas = platform_window.sprite_atlas();
 417        let mouse_position = platform_window.mouse_position();
 418        let modifiers = platform_window.modifiers();
 419        let content_size = platform_window.content_size();
 420        let scale_factor = platform_window.scale_factor();
 421        let appearance = platform_window.appearance();
 422        let text_system = Arc::new(WindowTextSystem::new(cx.text_system().clone()));
 423        let dirty = Rc::new(Cell::new(true));
 424        let active = Rc::new(Cell::new(platform_window.is_active()));
 425        let needs_present = Rc::new(Cell::new(false));
 426        let next_frame_callbacks: Rc<RefCell<Vec<FrameCallback>>> = Default::default();
 427        let last_input_timestamp = Rc::new(Cell::new(Instant::now()));
 428
 429        if fullscreen {
 430            platform_window.toggle_fullscreen();
 431        }
 432
 433        platform_window.on_close(Box::new({
 434            let mut cx = cx.to_async();
 435            move || {
 436                let _ = handle.update(&mut cx, |_, cx| cx.remove_window());
 437            }
 438        }));
 439        platform_window.on_request_frame(Box::new({
 440            let mut cx = cx.to_async();
 441            let dirty = dirty.clone();
 442            let active = active.clone();
 443            let needs_present = needs_present.clone();
 444            let next_frame_callbacks = next_frame_callbacks.clone();
 445            let last_input_timestamp = last_input_timestamp.clone();
 446            move || {
 447                let next_frame_callbacks = next_frame_callbacks.take();
 448                if !next_frame_callbacks.is_empty() {
 449                    handle
 450                        .update(&mut cx, |_, cx| {
 451                            for callback in next_frame_callbacks {
 452                                callback(cx);
 453                            }
 454                        })
 455                        .log_err();
 456                }
 457
 458                // Keep presenting the current scene for 1 extra second since the
 459                // last input to prevent the display from underclocking the refresh rate.
 460                let needs_present = needs_present.get()
 461                    || (active.get()
 462                        && last_input_timestamp.get().elapsed() < Duration::from_secs(1));
 463
 464                if dirty.get() {
 465                    measure("frame duration", || {
 466                        handle
 467                            .update(&mut cx, |_, cx| {
 468                                cx.draw();
 469                                cx.present();
 470                            })
 471                            .log_err();
 472                    })
 473                } else if needs_present {
 474                    handle.update(&mut cx, |_, cx| cx.present()).log_err();
 475                }
 476            }
 477        }));
 478        platform_window.on_resize(Box::new({
 479            let mut cx = cx.to_async();
 480            move |_, _| {
 481                handle
 482                    .update(&mut cx, |_, cx| cx.window_bounds_changed())
 483                    .log_err();
 484            }
 485        }));
 486        platform_window.on_moved(Box::new({
 487            let mut cx = cx.to_async();
 488            move || {
 489                handle
 490                    .update(&mut cx, |_, cx| cx.window_bounds_changed())
 491                    .log_err();
 492            }
 493        }));
 494        platform_window.on_appearance_changed(Box::new({
 495            let mut cx = cx.to_async();
 496            move || {
 497                handle
 498                    .update(&mut cx, |_, cx| cx.appearance_changed())
 499                    .log_err();
 500            }
 501        }));
 502        platform_window.on_active_status_change(Box::new({
 503            let mut cx = cx.to_async();
 504            move |active| {
 505                handle
 506                    .update(&mut cx, |_, cx| {
 507                        cx.window.active.set(active);
 508                        cx.window
 509                            .activation_observers
 510                            .clone()
 511                            .retain(&(), |callback| callback(cx));
 512                        cx.refresh();
 513                    })
 514                    .log_err();
 515            }
 516        }));
 517
 518        platform_window.on_input({
 519            let mut cx = cx.to_async();
 520            Box::new(move |event| {
 521                handle
 522                    .update(&mut cx, |_, cx| cx.dispatch_event(event))
 523                    .log_err()
 524                    .unwrap_or(DispatchEventResult::default())
 525            })
 526        });
 527
 528        Window {
 529            handle,
 530            removed: false,
 531            platform_window,
 532            display_id,
 533            sprite_atlas,
 534            text_system,
 535            rem_size: px(16.),
 536            viewport_size: content_size,
 537            layout_engine: Some(TaffyLayoutEngine::new()),
 538            root_view: None,
 539            element_id_stack: GlobalElementId::default(),
 540            text_style_stack: Vec::new(),
 541            rendered_frame: Frame::new(DispatchTree::new(cx.keymap.clone(), cx.actions.clone())),
 542            next_frame: Frame::new(DispatchTree::new(cx.keymap.clone(), cx.actions.clone())),
 543            next_frame_callbacks,
 544            next_hitbox_id: HitboxId::default(),
 545            dirty_views: FxHashSet::default(),
 546            focus_handles: Arc::new(RwLock::new(SlotMap::with_key())),
 547            focus_listeners: SubscriberSet::new(),
 548            focus_lost_listeners: SubscriberSet::new(),
 549            default_prevented: true,
 550            mouse_position,
 551            mouse_hit_test: HitTest::default(),
 552            modifiers,
 553            scale_factor,
 554            bounds_observers: SubscriberSet::new(),
 555            appearance,
 556            appearance_observers: SubscriberSet::new(),
 557            active,
 558            dirty,
 559            needs_present,
 560            last_input_timestamp,
 561            refreshing: false,
 562            draw_phase: DrawPhase::None,
 563            activation_observers: SubscriberSet::new(),
 564            focus: None,
 565            focus_enabled: true,
 566            pending_input: None,
 567            prompt: None,
 568        }
 569    }
 570    fn new_focus_listener(
 571        &mut self,
 572        value: AnyWindowFocusListener,
 573    ) -> (Subscription, impl FnOnce()) {
 574        self.focus_listeners.insert((), value)
 575    }
 576}
 577
 578#[derive(Clone, Debug, Default, PartialEq, Eq)]
 579pub(crate) struct DispatchEventResult {
 580    pub propagate: bool,
 581    pub default_prevented: bool,
 582}
 583
 584/// Indicates which region of the window is visible. Content falling outside of this mask will not be
 585/// rendered. Currently, only rectangular content masks are supported, but we give the mask its own type
 586/// to leave room to support more complex shapes in the future.
 587#[derive(Clone, Debug, Default, PartialEq, Eq)]
 588#[repr(C)]
 589pub struct ContentMask<P: Clone + Default + Debug> {
 590    /// The bounds
 591    pub bounds: Bounds<P>,
 592}
 593
 594impl ContentMask<Pixels> {
 595    /// Scale the content mask's pixel units by the given scaling factor.
 596    pub fn scale(&self, factor: f32) -> ContentMask<ScaledPixels> {
 597        ContentMask {
 598            bounds: self.bounds.scale(factor),
 599        }
 600    }
 601
 602    /// Intersect the content mask with the given content mask.
 603    pub fn intersect(&self, other: &Self) -> Self {
 604        let bounds = self.bounds.intersect(&other.bounds);
 605        ContentMask { bounds }
 606    }
 607}
 608
 609/// Provides access to application state in the context of a single window. Derefs
 610/// to an [`AppContext`], so you can also pass a [`WindowContext`] to any method that takes
 611/// an [`AppContext`] and call any [`AppContext`] methods.
 612pub struct WindowContext<'a> {
 613    pub(crate) app: &'a mut AppContext,
 614    pub(crate) window: &'a mut Window,
 615}
 616
 617impl<'a> WindowContext<'a> {
 618    pub(crate) fn new(app: &'a mut AppContext, window: &'a mut Window) -> Self {
 619        Self { app, window }
 620    }
 621
 622    /// Obtain a handle to the window that belongs to this context.
 623    pub fn window_handle(&self) -> AnyWindowHandle {
 624        self.window.handle
 625    }
 626
 627    /// Mark the window as dirty, scheduling it to be redrawn on the next frame.
 628    pub fn refresh(&mut self) {
 629        if self.window.draw_phase == DrawPhase::None {
 630            self.window.refreshing = true;
 631            self.window.dirty.set(true);
 632        }
 633    }
 634
 635    /// Indicate that this view has changed, which will invoke any observers and also mark the window as dirty.
 636    /// If this view or any of its ancestors are *cached*, notifying it will cause it or its ancestors to be redrawn.
 637    pub fn notify(&mut self, view_id: EntityId) {
 638        for view_id in self
 639            .window
 640            .rendered_frame
 641            .dispatch_tree
 642            .view_path(view_id)
 643            .into_iter()
 644            .rev()
 645        {
 646            if !self.window.dirty_views.insert(view_id) {
 647                break;
 648            }
 649        }
 650
 651        if self.window.draw_phase == DrawPhase::None {
 652            self.window.dirty.set(true);
 653            self.app.push_effect(Effect::Notify { emitter: view_id });
 654        }
 655    }
 656
 657    /// Close this window.
 658    pub fn remove_window(&mut self) {
 659        self.window.removed = true;
 660    }
 661
 662    /// Obtain a new [`FocusHandle`], which allows you to track and manipulate the keyboard focus
 663    /// for elements rendered within this window.
 664    pub fn focus_handle(&mut self) -> FocusHandle {
 665        FocusHandle::new(&self.window.focus_handles)
 666    }
 667
 668    /// Obtain the currently focused [`FocusHandle`]. If no elements are focused, returns `None`.
 669    pub fn focused(&self) -> Option<FocusHandle> {
 670        self.window
 671            .focus
 672            .and_then(|id| FocusHandle::for_id(id, &self.window.focus_handles))
 673    }
 674
 675    /// Move focus to the element associated with the given [`FocusHandle`].
 676    pub fn focus(&mut self, handle: &FocusHandle) {
 677        if !self.window.focus_enabled || self.window.focus == Some(handle.id) {
 678            return;
 679        }
 680
 681        self.window.focus = Some(handle.id);
 682        self.window
 683            .rendered_frame
 684            .dispatch_tree
 685            .clear_pending_keystrokes();
 686        self.refresh();
 687    }
 688
 689    /// Remove focus from all elements within this context's window.
 690    pub fn blur(&mut self) {
 691        if !self.window.focus_enabled {
 692            return;
 693        }
 694
 695        self.window.focus = None;
 696        self.refresh();
 697    }
 698
 699    /// Blur the window and don't allow anything in it to be focused again.
 700    pub fn disable_focus(&mut self) {
 701        self.blur();
 702        self.window.focus_enabled = false;
 703    }
 704
 705    /// Accessor for the text system.
 706    pub fn text_system(&self) -> &Arc<WindowTextSystem> {
 707        &self.window.text_system
 708    }
 709
 710    /// The current text style. Which is composed of all the style refinements provided to `with_text_style`.
 711    pub fn text_style(&self) -> TextStyle {
 712        let mut style = TextStyle::default();
 713        for refinement in &self.window.text_style_stack {
 714            style.refine(refinement);
 715        }
 716        style
 717    }
 718
 719    /// Check if the platform window is maximized
 720    /// On some platforms (namely Windows) this is different than the bounds being the size of the display
 721    pub fn is_maximized(&self) -> bool {
 722        self.window.platform_window.is_maximized()
 723    }
 724
 725    /// Check if the platform window is minimized
 726    /// On some platforms (namely Windows) the position is incorrect when minimized
 727    pub fn is_minimized(&self) -> bool {
 728        self.window.platform_window.is_minimized()
 729    }
 730
 731    /// Dispatch the given action on the currently focused element.
 732    pub fn dispatch_action(&mut self, action: Box<dyn Action>) {
 733        let focus_handle = self.focused();
 734
 735        let window = self.window.handle;
 736        self.app.defer(move |cx| {
 737            window
 738                .update(cx, |_, cx| {
 739                    let node_id = focus_handle
 740                        .and_then(|handle| {
 741                            cx.window
 742                                .rendered_frame
 743                                .dispatch_tree
 744                                .focusable_node_id(handle.id)
 745                        })
 746                        .unwrap_or_else(|| cx.window.rendered_frame.dispatch_tree.root_node_id());
 747
 748                    cx.dispatch_action_on_node(node_id, action.as_ref());
 749                })
 750                .log_err();
 751        })
 752    }
 753
 754    pub(crate) fn dispatch_keystroke_observers(
 755        &mut self,
 756        event: &dyn Any,
 757        action: Option<Box<dyn Action>>,
 758    ) {
 759        let Some(key_down_event) = event.downcast_ref::<KeyDownEvent>() else {
 760            return;
 761        };
 762
 763        self.keystroke_observers
 764            .clone()
 765            .retain(&(), move |callback| {
 766                (callback)(
 767                    &KeystrokeEvent {
 768                        keystroke: key_down_event.keystroke.clone(),
 769                        action: action.as_ref().map(|action| action.boxed_clone()),
 770                    },
 771                    self,
 772                );
 773                true
 774            });
 775    }
 776
 777    pub(crate) fn clear_pending_keystrokes(&mut self) {
 778        self.window
 779            .rendered_frame
 780            .dispatch_tree
 781            .clear_pending_keystrokes();
 782        self.window
 783            .next_frame
 784            .dispatch_tree
 785            .clear_pending_keystrokes();
 786    }
 787
 788    /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
 789    /// that are currently on the stack to be returned to the app.
 790    pub fn defer(&mut self, f: impl FnOnce(&mut WindowContext) + 'static) {
 791        let handle = self.window.handle;
 792        self.app.defer(move |cx| {
 793            handle.update(cx, |_, cx| f(cx)).ok();
 794        });
 795    }
 796
 797    /// Subscribe to events emitted by a model or view.
 798    /// The entity to which you're subscribing must implement the [`EventEmitter`] trait.
 799    /// The callback will be invoked a handle to the emitting entity (either a [`View`] or [`Model`]), the event, and a window context for the current window.
 800    pub fn subscribe<Emitter, E, Evt>(
 801        &mut self,
 802        entity: &E,
 803        mut on_event: impl FnMut(E, &Evt, &mut WindowContext<'_>) + 'static,
 804    ) -> Subscription
 805    where
 806        Emitter: EventEmitter<Evt>,
 807        E: Entity<Emitter>,
 808        Evt: 'static,
 809    {
 810        let entity_id = entity.entity_id();
 811        let entity = entity.downgrade();
 812        let window_handle = self.window.handle;
 813        self.app.new_subscription(
 814            entity_id,
 815            (
 816                TypeId::of::<Evt>(),
 817                Box::new(move |event, cx| {
 818                    window_handle
 819                        .update(cx, |_, cx| {
 820                            if let Some(handle) = E::upgrade_from(&entity) {
 821                                let event = event.downcast_ref().expect("invalid event type");
 822                                on_event(handle, event, cx);
 823                                true
 824                            } else {
 825                                false
 826                            }
 827                        })
 828                        .unwrap_or(false)
 829                }),
 830            ),
 831        )
 832    }
 833
 834    /// Creates an [`AsyncWindowContext`], which has a static lifetime and can be held across
 835    /// await points in async code.
 836    pub fn to_async(&self) -> AsyncWindowContext {
 837        AsyncWindowContext::new(self.app.to_async(), self.window.handle)
 838    }
 839
 840    /// Schedule the given closure to be run directly after the current frame is rendered.
 841    pub fn on_next_frame(&mut self, callback: impl FnOnce(&mut WindowContext) + 'static) {
 842        RefCell::borrow_mut(&self.window.next_frame_callbacks).push(Box::new(callback));
 843    }
 844
 845    /// Spawn the future returned by the given closure on the application thread pool.
 846    /// The closure is provided a handle to the current window and an `AsyncWindowContext` for
 847    /// use within your future.
 848    pub fn spawn<Fut, R>(&mut self, f: impl FnOnce(AsyncWindowContext) -> Fut) -> Task<R>
 849    where
 850        R: 'static,
 851        Fut: Future<Output = R> + 'static,
 852    {
 853        self.app
 854            .spawn(|app| f(AsyncWindowContext::new(app, self.window.handle)))
 855    }
 856
 857    fn window_bounds_changed(&mut self) {
 858        self.window.scale_factor = self.window.platform_window.scale_factor();
 859        self.window.viewport_size = self.window.platform_window.content_size();
 860        self.window.display_id = self.window.platform_window.display().id();
 861        self.refresh();
 862
 863        self.window
 864            .bounds_observers
 865            .clone()
 866            .retain(&(), |callback| callback(self));
 867    }
 868
 869    /// Returns the bounds of the current window in the global coordinate space, which could span across multiple displays.
 870    pub fn window_bounds(&self) -> Bounds<GlobalPixels> {
 871        self.window.platform_window.bounds()
 872    }
 873
 874    /// Retusn whether or not the window is currently fullscreen
 875    pub fn is_fullscreen(&self) -> bool {
 876        self.window.platform_window.is_fullscreen()
 877    }
 878
 879    fn appearance_changed(&mut self) {
 880        self.window.appearance = self.window.platform_window.appearance();
 881
 882        self.window
 883            .appearance_observers
 884            .clone()
 885            .retain(&(), |callback| callback(self));
 886    }
 887
 888    /// Returns the appearance of the current window.
 889    pub fn appearance(&self) -> WindowAppearance {
 890        self.window.appearance
 891    }
 892
 893    /// Returns the size of the drawable area within the window.
 894    pub fn viewport_size(&self) -> Size<Pixels> {
 895        self.window.viewport_size
 896    }
 897
 898    /// Returns whether this window is focused by the operating system (receiving key events).
 899    pub fn is_window_active(&self) -> bool {
 900        self.window.active.get()
 901    }
 902
 903    /// Toggle zoom on the window.
 904    pub fn zoom_window(&self) {
 905        self.window.platform_window.zoom();
 906    }
 907
 908    /// Updates the window's title at the platform level.
 909    pub fn set_window_title(&mut self, title: &str) {
 910        self.window.platform_window.set_title(title);
 911    }
 912
 913    /// Mark the window as dirty at the platform level.
 914    pub fn set_window_edited(&mut self, edited: bool) {
 915        self.window.platform_window.set_edited(edited);
 916    }
 917
 918    /// Determine the display on which the window is visible.
 919    pub fn display(&self) -> Option<Rc<dyn PlatformDisplay>> {
 920        self.platform
 921            .displays()
 922            .into_iter()
 923            .find(|display| display.id() == self.window.display_id)
 924    }
 925
 926    /// Show the platform character palette.
 927    pub fn show_character_palette(&self) {
 928        self.window.platform_window.show_character_palette();
 929    }
 930
 931    /// The scale factor of the display associated with the window. For example, it could
 932    /// return 2.0 for a "retina" display, indicating that each logical pixel should actually
 933    /// be rendered as two pixels on screen.
 934    pub fn scale_factor(&self) -> f32 {
 935        self.window.scale_factor
 936    }
 937
 938    /// The size of an em for the base font of the application. Adjusting this value allows the
 939    /// UI to scale, just like zooming a web page.
 940    pub fn rem_size(&self) -> Pixels {
 941        self.window.rem_size
 942    }
 943
 944    /// Sets the size of an em for the base font of the application. Adjusting this value allows the
 945    /// UI to scale, just like zooming a web page.
 946    pub fn set_rem_size(&mut self, rem_size: impl Into<Pixels>) {
 947        self.window.rem_size = rem_size.into();
 948    }
 949
 950    /// The line height associated with the current text style.
 951    pub fn line_height(&self) -> Pixels {
 952        let rem_size = self.rem_size();
 953        let text_style = self.text_style();
 954        text_style
 955            .line_height
 956            .to_pixels(text_style.font_size, rem_size)
 957    }
 958
 959    /// Call to prevent the default action of an event. Currently only used to prevent
 960    /// parent elements from becoming focused on mouse down.
 961    pub fn prevent_default(&mut self) {
 962        self.window.default_prevented = true;
 963    }
 964
 965    /// Obtain whether default has been prevented for the event currently being dispatched.
 966    pub fn default_prevented(&self) -> bool {
 967        self.window.default_prevented
 968    }
 969
 970    /// Determine whether the given action is available along the dispatch path to the currently focused element.
 971    pub fn is_action_available(&self, action: &dyn Action) -> bool {
 972        let target = self
 973            .focused()
 974            .and_then(|focused_handle| {
 975                self.window
 976                    .rendered_frame
 977                    .dispatch_tree
 978                    .focusable_node_id(focused_handle.id)
 979            })
 980            .unwrap_or_else(|| self.window.rendered_frame.dispatch_tree.root_node_id());
 981        self.window
 982            .rendered_frame
 983            .dispatch_tree
 984            .is_action_available(action, target)
 985    }
 986
 987    /// The position of the mouse relative to the window.
 988    pub fn mouse_position(&self) -> Point<Pixels> {
 989        self.window.mouse_position
 990    }
 991
 992    /// The current state of the keyboard's modifiers
 993    pub fn modifiers(&self) -> Modifiers {
 994        self.window.modifiers
 995    }
 996
 997    /// Produces a new frame and assigns it to `rendered_frame`. To actually show
 998    /// the contents of the new [Scene], use [present].
 999    #[profiling::function]
1000    pub fn draw(&mut self) {
1001        self.window.dirty.set(false);
1002
1003        // Restore the previously-used input handler.
1004        if let Some(input_handler) = self.window.platform_window.take_input_handler() {
1005            self.window
1006                .rendered_frame
1007                .input_handlers
1008                .push(Some(input_handler));
1009        }
1010
1011        self.with_element_context(|cx| cx.draw_roots());
1012        self.window.dirty_views.clear();
1013
1014        self.window
1015            .next_frame
1016            .dispatch_tree
1017            .preserve_pending_keystrokes(
1018                &mut self.window.rendered_frame.dispatch_tree,
1019                self.window.focus,
1020            );
1021        self.window.next_frame.focus = self.window.focus;
1022        self.window.next_frame.window_active = self.window.active.get();
1023
1024        // Register requested input handler with the platform window.
1025        if let Some(input_handler) = self.window.next_frame.input_handlers.pop() {
1026            self.window
1027                .platform_window
1028                .set_input_handler(input_handler.unwrap());
1029        }
1030
1031        self.window.layout_engine.as_mut().unwrap().clear();
1032        self.text_system().finish_frame();
1033        self.window
1034            .next_frame
1035            .finish(&mut self.window.rendered_frame);
1036        ELEMENT_ARENA.with_borrow_mut(|element_arena| {
1037            let percentage = (element_arena.len() as f32 / element_arena.capacity() as f32) * 100.;
1038            if percentage >= 80. {
1039                log::warn!("elevated element arena occupation: {}.", percentage);
1040            }
1041            element_arena.clear();
1042        });
1043
1044        self.window.draw_phase = DrawPhase::Focus;
1045        let previous_focus_path = self.window.rendered_frame.focus_path();
1046        let previous_window_active = self.window.rendered_frame.window_active;
1047        mem::swap(&mut self.window.rendered_frame, &mut self.window.next_frame);
1048        self.window.next_frame.clear();
1049        let current_focus_path = self.window.rendered_frame.focus_path();
1050        let current_window_active = self.window.rendered_frame.window_active;
1051
1052        if previous_focus_path != current_focus_path
1053            || previous_window_active != current_window_active
1054        {
1055            if !previous_focus_path.is_empty() && current_focus_path.is_empty() {
1056                self.window
1057                    .focus_lost_listeners
1058                    .clone()
1059                    .retain(&(), |listener| listener(self));
1060            }
1061
1062            let event = FocusEvent {
1063                previous_focus_path: if previous_window_active {
1064                    previous_focus_path
1065                } else {
1066                    Default::default()
1067                },
1068                current_focus_path: if current_window_active {
1069                    current_focus_path
1070                } else {
1071                    Default::default()
1072                },
1073            };
1074            self.window
1075                .focus_listeners
1076                .clone()
1077                .retain(&(), |listener| listener(&event, self));
1078        }
1079
1080        self.reset_cursor_style();
1081        self.window.refreshing = false;
1082        self.window.draw_phase = DrawPhase::None;
1083        self.window.needs_present.set(true);
1084    }
1085
1086    #[profiling::function]
1087    fn present(&self) {
1088        self.window
1089            .platform_window
1090            .draw(&self.window.rendered_frame.scene);
1091        self.window.needs_present.set(false);
1092        profiling::finish_frame!();
1093    }
1094
1095    fn reset_cursor_style(&self) {
1096        // Set the cursor only if we're the active window.
1097        if self.is_window_active() {
1098            let style = self
1099                .window
1100                .rendered_frame
1101                .cursor_styles
1102                .iter()
1103                .rev()
1104                .find(|request| request.hitbox_id.is_hovered(self))
1105                .map(|request| request.style)
1106                .unwrap_or(CursorStyle::Arrow);
1107            self.platform.set_cursor_style(style);
1108        }
1109    }
1110
1111    /// Dispatch a given keystroke as though the user had typed it.
1112    /// You can create a keystroke with Keystroke::parse("").
1113    pub fn dispatch_keystroke(&mut self, keystroke: Keystroke) -> bool {
1114        let keystroke = keystroke.with_simulated_ime();
1115        let result = self.dispatch_event(PlatformInput::KeyDown(KeyDownEvent {
1116            keystroke: keystroke.clone(),
1117            is_held: false,
1118        }));
1119        if !result.propagate {
1120            return true;
1121        }
1122
1123        if let Some(input) = keystroke.ime_key {
1124            if let Some(mut input_handler) = self.window.platform_window.take_input_handler() {
1125                input_handler.dispatch_input(&input, self);
1126                self.window.platform_window.set_input_handler(input_handler);
1127                return true;
1128            }
1129        }
1130
1131        false
1132    }
1133
1134    /// Represent this action as a key binding string, to display in the UI.
1135    pub fn keystroke_text_for(&self, action: &dyn Action) -> String {
1136        self.bindings_for_action(action)
1137            .into_iter()
1138            .next()
1139            .map(|binding| {
1140                binding
1141                    .keystrokes()
1142                    .iter()
1143                    .map(ToString::to_string)
1144                    .collect::<Vec<_>>()
1145                    .join(" ")
1146            })
1147            .unwrap_or_else(|| action.name().to_string())
1148    }
1149
1150    /// Dispatch a mouse or keyboard event on the window.
1151    #[profiling::function]
1152    pub fn dispatch_event(&mut self, event: PlatformInput) -> DispatchEventResult {
1153        self.window.last_input_timestamp.set(Instant::now());
1154        // Handlers may set this to false by calling `stop_propagation`.
1155        self.app.propagate_event = true;
1156        // Handlers may set this to true by calling `prevent_default`.
1157        self.window.default_prevented = false;
1158
1159        let event = match event {
1160            // Track the mouse position with our own state, since accessing the platform
1161            // API for the mouse position can only occur on the main thread.
1162            PlatformInput::MouseMove(mouse_move) => {
1163                self.window.mouse_position = mouse_move.position;
1164                self.window.modifiers = mouse_move.modifiers;
1165                PlatformInput::MouseMove(mouse_move)
1166            }
1167            PlatformInput::MouseDown(mouse_down) => {
1168                self.window.mouse_position = mouse_down.position;
1169                self.window.modifiers = mouse_down.modifiers;
1170                PlatformInput::MouseDown(mouse_down)
1171            }
1172            PlatformInput::MouseUp(mouse_up) => {
1173                self.window.mouse_position = mouse_up.position;
1174                self.window.modifiers = mouse_up.modifiers;
1175                PlatformInput::MouseUp(mouse_up)
1176            }
1177            PlatformInput::MouseExited(mouse_exited) => {
1178                self.window.modifiers = mouse_exited.modifiers;
1179                PlatformInput::MouseExited(mouse_exited)
1180            }
1181            PlatformInput::ModifiersChanged(modifiers_changed) => {
1182                self.window.modifiers = modifiers_changed.modifiers;
1183                PlatformInput::ModifiersChanged(modifiers_changed)
1184            }
1185            PlatformInput::ScrollWheel(scroll_wheel) => {
1186                self.window.mouse_position = scroll_wheel.position;
1187                self.window.modifiers = scroll_wheel.modifiers;
1188                PlatformInput::ScrollWheel(scroll_wheel)
1189            }
1190            // Translate dragging and dropping of external files from the operating system
1191            // to internal drag and drop events.
1192            PlatformInput::FileDrop(file_drop) => match file_drop {
1193                FileDropEvent::Entered { position, paths } => {
1194                    self.window.mouse_position = position;
1195                    if self.active_drag.is_none() {
1196                        self.active_drag = Some(AnyDrag {
1197                            value: Box::new(paths.clone()),
1198                            view: self.new_view(|_| paths).into(),
1199                            cursor_offset: position,
1200                        });
1201                    }
1202                    PlatformInput::MouseMove(MouseMoveEvent {
1203                        position,
1204                        pressed_button: Some(MouseButton::Left),
1205                        modifiers: Modifiers::default(),
1206                    })
1207                }
1208                FileDropEvent::Pending { position } => {
1209                    self.window.mouse_position = position;
1210                    PlatformInput::MouseMove(MouseMoveEvent {
1211                        position,
1212                        pressed_button: Some(MouseButton::Left),
1213                        modifiers: Modifiers::default(),
1214                    })
1215                }
1216                FileDropEvent::Submit { position } => {
1217                    self.activate(true);
1218                    self.window.mouse_position = position;
1219                    PlatformInput::MouseUp(MouseUpEvent {
1220                        button: MouseButton::Left,
1221                        position,
1222                        modifiers: Modifiers::default(),
1223                        click_count: 1,
1224                    })
1225                }
1226                FileDropEvent::Exited => {
1227                    self.active_drag.take();
1228                    PlatformInput::FileDrop(FileDropEvent::Exited)
1229                }
1230            },
1231            PlatformInput::KeyDown(_) | PlatformInput::KeyUp(_) => event,
1232        };
1233
1234        if let Some(any_mouse_event) = event.mouse_event() {
1235            self.dispatch_mouse_event(any_mouse_event);
1236        } else if let Some(any_key_event) = event.keyboard_event() {
1237            self.dispatch_key_event(any_key_event);
1238        }
1239
1240        DispatchEventResult {
1241            propagate: self.app.propagate_event,
1242            default_prevented: self.window.default_prevented,
1243        }
1244    }
1245
1246    fn dispatch_mouse_event(&mut self, event: &dyn Any) {
1247        let hit_test = self.window.rendered_frame.hit_test(self.mouse_position());
1248        if hit_test != self.window.mouse_hit_test {
1249            self.window.mouse_hit_test = hit_test;
1250            self.reset_cursor_style();
1251        }
1252
1253        let mut mouse_listeners = mem::take(&mut self.window.rendered_frame.mouse_listeners);
1254        self.with_element_context(|cx| {
1255            // Capture phase, events bubble from back to front. Handlers for this phase are used for
1256            // special purposes, such as detecting events outside of a given Bounds.
1257            for listener in &mut mouse_listeners {
1258                let listener = listener.as_mut().unwrap();
1259                listener(event, DispatchPhase::Capture, cx);
1260                if !cx.app.propagate_event {
1261                    break;
1262                }
1263            }
1264
1265            // Bubble phase, where most normal handlers do their work.
1266            if cx.app.propagate_event {
1267                for listener in mouse_listeners.iter_mut().rev() {
1268                    let listener = listener.as_mut().unwrap();
1269                    listener(event, DispatchPhase::Bubble, cx);
1270                    if !cx.app.propagate_event {
1271                        break;
1272                    }
1273                }
1274            }
1275        });
1276        self.window.rendered_frame.mouse_listeners = mouse_listeners;
1277
1278        if self.app.propagate_event && self.has_active_drag() {
1279            if event.is::<MouseMoveEvent>() {
1280                // If this was a mouse move event, redraw the window so that the
1281                // active drag can follow the mouse cursor.
1282                self.refresh();
1283            } else if event.is::<MouseUpEvent>() {
1284                // If this was a mouse up event, cancel the active drag and redraw
1285                // the window.
1286                self.active_drag = None;
1287                self.refresh();
1288            }
1289        }
1290    }
1291
1292    fn dispatch_key_event(&mut self, event: &dyn Any) {
1293        if self.window.dirty.get() {
1294            self.draw();
1295        }
1296
1297        let node_id = self
1298            .window
1299            .focus
1300            .and_then(|focus_id| {
1301                self.window
1302                    .rendered_frame
1303                    .dispatch_tree
1304                    .focusable_node_id(focus_id)
1305            })
1306            .unwrap_or_else(|| self.window.rendered_frame.dispatch_tree.root_node_id());
1307
1308        let dispatch_path = self
1309            .window
1310            .rendered_frame
1311            .dispatch_tree
1312            .dispatch_path(node_id);
1313
1314        if let Some(key_down_event) = event.downcast_ref::<KeyDownEvent>() {
1315            let KeymatchResult { bindings, pending } = self
1316                .window
1317                .rendered_frame
1318                .dispatch_tree
1319                .dispatch_key(&key_down_event.keystroke, &dispatch_path);
1320
1321            if pending {
1322                let mut currently_pending = self.window.pending_input.take().unwrap_or_default();
1323                if currently_pending.focus.is_some() && currently_pending.focus != self.window.focus
1324                {
1325                    currently_pending = PendingInput::default();
1326                }
1327                currently_pending.focus = self.window.focus;
1328                currently_pending
1329                    .keystrokes
1330                    .push(key_down_event.keystroke.clone());
1331                for binding in bindings {
1332                    currently_pending.bindings.push(binding);
1333                }
1334
1335                currently_pending.timer = Some(self.spawn(|mut cx| async move {
1336                    cx.background_executor.timer(Duration::from_secs(1)).await;
1337                    cx.update(move |cx| {
1338                        cx.clear_pending_keystrokes();
1339                        let Some(currently_pending) = cx.window.pending_input.take() else {
1340                            return;
1341                        };
1342                        cx.replay_pending_input(currently_pending)
1343                    })
1344                    .log_err();
1345                }));
1346
1347                self.window.pending_input = Some(currently_pending);
1348
1349                self.propagate_event = false;
1350                return;
1351            } else if let Some(currently_pending) = self.window.pending_input.take() {
1352                if bindings
1353                    .iter()
1354                    .all(|binding| !currently_pending.used_by_binding(binding))
1355                {
1356                    self.replay_pending_input(currently_pending)
1357                }
1358            }
1359
1360            if !bindings.is_empty() {
1361                self.clear_pending_keystrokes();
1362            }
1363
1364            self.propagate_event = true;
1365            for binding in bindings {
1366                self.dispatch_action_on_node(node_id, binding.action.as_ref());
1367                if !self.propagate_event {
1368                    self.dispatch_keystroke_observers(event, Some(binding.action));
1369                    return;
1370                }
1371            }
1372        }
1373
1374        self.dispatch_key_down_up_event(event, &dispatch_path);
1375        if !self.propagate_event {
1376            return;
1377        }
1378
1379        self.dispatch_modifiers_changed_event(event, &dispatch_path);
1380        if !self.propagate_event {
1381            return;
1382        }
1383
1384        self.dispatch_keystroke_observers(event, None);
1385    }
1386
1387    fn dispatch_key_down_up_event(
1388        &mut self,
1389        event: &dyn Any,
1390        dispatch_path: &SmallVec<[DispatchNodeId; 32]>,
1391    ) {
1392        // Capture phase
1393        for node_id in dispatch_path {
1394            let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1395
1396            for key_listener in node.key_listeners.clone() {
1397                self.with_element_context(|cx| {
1398                    key_listener(event, DispatchPhase::Capture, cx);
1399                });
1400                if !self.propagate_event {
1401                    return;
1402                }
1403            }
1404        }
1405
1406        // Bubble phase
1407        for node_id in dispatch_path.iter().rev() {
1408            // Handle low level key events
1409            let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1410            for key_listener in node.key_listeners.clone() {
1411                self.with_element_context(|cx| {
1412                    key_listener(event, DispatchPhase::Bubble, cx);
1413                });
1414                if !self.propagate_event {
1415                    return;
1416                }
1417            }
1418        }
1419    }
1420
1421    fn dispatch_modifiers_changed_event(
1422        &mut self,
1423        event: &dyn Any,
1424        dispatch_path: &SmallVec<[DispatchNodeId; 32]>,
1425    ) {
1426        let Some(event) = event.downcast_ref::<ModifiersChangedEvent>() else {
1427            return;
1428        };
1429        for node_id in dispatch_path.iter().rev() {
1430            let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1431            for listener in node.modifiers_changed_listeners.clone() {
1432                self.with_element_context(|cx| {
1433                    listener(event, cx);
1434                });
1435                if !self.propagate_event {
1436                    return;
1437                }
1438            }
1439        }
1440    }
1441
1442    /// Determine whether a potential multi-stroke key binding is in progress on this window.
1443    pub fn has_pending_keystrokes(&self) -> bool {
1444        self.window
1445            .rendered_frame
1446            .dispatch_tree
1447            .has_pending_keystrokes()
1448    }
1449
1450    fn replay_pending_input(&mut self, currently_pending: PendingInput) {
1451        let node_id = self
1452            .window
1453            .focus
1454            .and_then(|focus_id| {
1455                self.window
1456                    .rendered_frame
1457                    .dispatch_tree
1458                    .focusable_node_id(focus_id)
1459            })
1460            .unwrap_or_else(|| self.window.rendered_frame.dispatch_tree.root_node_id());
1461
1462        if self.window.focus != currently_pending.focus {
1463            return;
1464        }
1465
1466        let input = currently_pending.input();
1467
1468        self.propagate_event = true;
1469        for binding in currently_pending.bindings {
1470            self.dispatch_action_on_node(node_id, binding.action.as_ref());
1471            if !self.propagate_event {
1472                return;
1473            }
1474        }
1475
1476        let dispatch_path = self
1477            .window
1478            .rendered_frame
1479            .dispatch_tree
1480            .dispatch_path(node_id);
1481
1482        for keystroke in currently_pending.keystrokes {
1483            let event = KeyDownEvent {
1484                keystroke,
1485                is_held: false,
1486            };
1487
1488            self.dispatch_key_down_up_event(&event, &dispatch_path);
1489            if !self.propagate_event {
1490                return;
1491            }
1492        }
1493
1494        if !input.is_empty() {
1495            if let Some(mut input_handler) = self.window.platform_window.take_input_handler() {
1496                input_handler.dispatch_input(&input, self);
1497                self.window.platform_window.set_input_handler(input_handler)
1498            }
1499        }
1500    }
1501
1502    fn dispatch_action_on_node(&mut self, node_id: DispatchNodeId, action: &dyn Action) {
1503        let dispatch_path = self
1504            .window
1505            .rendered_frame
1506            .dispatch_tree
1507            .dispatch_path(node_id);
1508
1509        // Capture phase for global actions.
1510        self.propagate_event = true;
1511        if let Some(mut global_listeners) = self
1512            .global_action_listeners
1513            .remove(&action.as_any().type_id())
1514        {
1515            for listener in &global_listeners {
1516                listener(action.as_any(), DispatchPhase::Capture, self);
1517                if !self.propagate_event {
1518                    break;
1519                }
1520            }
1521
1522            global_listeners.extend(
1523                self.global_action_listeners
1524                    .remove(&action.as_any().type_id())
1525                    .unwrap_or_default(),
1526            );
1527
1528            self.global_action_listeners
1529                .insert(action.as_any().type_id(), global_listeners);
1530        }
1531
1532        if !self.propagate_event {
1533            return;
1534        }
1535
1536        // Capture phase for window actions.
1537        for node_id in &dispatch_path {
1538            let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1539            for DispatchActionListener {
1540                action_type,
1541                listener,
1542            } in node.action_listeners.clone()
1543            {
1544                let any_action = action.as_any();
1545                if action_type == any_action.type_id() {
1546                    self.with_element_context(|cx| {
1547                        listener(any_action, DispatchPhase::Capture, cx);
1548                    });
1549
1550                    if !self.propagate_event {
1551                        return;
1552                    }
1553                }
1554            }
1555        }
1556
1557        // Bubble phase for window actions.
1558        for node_id in dispatch_path.iter().rev() {
1559            let node = self.window.rendered_frame.dispatch_tree.node(*node_id);
1560            for DispatchActionListener {
1561                action_type,
1562                listener,
1563            } in node.action_listeners.clone()
1564            {
1565                let any_action = action.as_any();
1566                if action_type == any_action.type_id() {
1567                    self.propagate_event = false; // Actions stop propagation by default during the bubble phase
1568
1569                    self.with_element_context(|cx| {
1570                        listener(any_action, DispatchPhase::Bubble, cx);
1571                    });
1572
1573                    if !self.propagate_event {
1574                        return;
1575                    }
1576                }
1577            }
1578        }
1579
1580        // Bubble phase for global actions.
1581        if let Some(mut global_listeners) = self
1582            .global_action_listeners
1583            .remove(&action.as_any().type_id())
1584        {
1585            for listener in global_listeners.iter().rev() {
1586                self.propagate_event = false; // Actions stop propagation by default during the bubble phase
1587
1588                listener(action.as_any(), DispatchPhase::Bubble, self);
1589                if !self.propagate_event {
1590                    break;
1591                }
1592            }
1593
1594            global_listeners.extend(
1595                self.global_action_listeners
1596                    .remove(&action.as_any().type_id())
1597                    .unwrap_or_default(),
1598            );
1599
1600            self.global_action_listeners
1601                .insert(action.as_any().type_id(), global_listeners);
1602        }
1603    }
1604
1605    /// Register the given handler to be invoked whenever the global of the given type
1606    /// is updated.
1607    pub fn observe_global<G: Global>(
1608        &mut self,
1609        f: impl Fn(&mut WindowContext<'_>) + 'static,
1610    ) -> Subscription {
1611        let window_handle = self.window.handle;
1612        let (subscription, activate) = self.global_observers.insert(
1613            TypeId::of::<G>(),
1614            Box::new(move |cx| window_handle.update(cx, |_, cx| f(cx)).is_ok()),
1615        );
1616        self.app.defer(move |_| activate());
1617        subscription
1618    }
1619
1620    /// Focus the current window and bring it to the foreground at the platform level.
1621    pub fn activate_window(&self) {
1622        self.window.platform_window.activate();
1623    }
1624
1625    /// Minimize the current window at the platform level.
1626    pub fn minimize_window(&self) {
1627        self.window.platform_window.minimize();
1628    }
1629
1630    /// Toggle full screen status on the current window at the platform level.
1631    pub fn toggle_fullscreen(&self) {
1632        self.window.platform_window.toggle_fullscreen();
1633    }
1634
1635    /// Present a platform dialog.
1636    /// The provided message will be presented, along with buttons for each answer.
1637    /// When a button is clicked, the returned Receiver will receive the index of the clicked button.
1638    pub fn prompt(
1639        &mut self,
1640        level: PromptLevel,
1641        message: &str,
1642        detail: Option<&str>,
1643        answers: &[&str],
1644    ) -> oneshot::Receiver<usize> {
1645        let prompt_builder = self.app.prompt_builder.take();
1646        let Some(prompt_builder) = prompt_builder else {
1647            unreachable!("Re-entrant window prompting is not supported by GPUI");
1648        };
1649
1650        let receiver = match &prompt_builder {
1651            PromptBuilder::Default => self
1652                .window
1653                .platform_window
1654                .prompt(level, message, detail, answers)
1655                .unwrap_or_else(|| {
1656                    self.build_custom_prompt(&prompt_builder, level, message, detail, answers)
1657                }),
1658            PromptBuilder::Custom(_) => {
1659                self.build_custom_prompt(&prompt_builder, level, message, detail, answers)
1660            }
1661        };
1662
1663        self.app.prompt_builder = Some(prompt_builder);
1664
1665        receiver
1666    }
1667
1668    fn build_custom_prompt(
1669        &mut self,
1670        prompt_builder: &PromptBuilder,
1671        level: PromptLevel,
1672        message: &str,
1673        detail: Option<&str>,
1674        answers: &[&str],
1675    ) -> oneshot::Receiver<usize> {
1676        let (sender, receiver) = oneshot::channel();
1677        let handle = PromptHandle::new(sender);
1678        let handle = (prompt_builder)(level, message, detail, answers, handle, self);
1679        self.window.prompt = Some(handle);
1680        receiver
1681    }
1682
1683    /// Returns all available actions for the focused element.
1684    pub fn available_actions(&self) -> Vec<Box<dyn Action>> {
1685        let node_id = self
1686            .window
1687            .focus
1688            .and_then(|focus_id| {
1689                self.window
1690                    .rendered_frame
1691                    .dispatch_tree
1692                    .focusable_node_id(focus_id)
1693            })
1694            .unwrap_or_else(|| self.window.rendered_frame.dispatch_tree.root_node_id());
1695
1696        let mut actions = self
1697            .window
1698            .rendered_frame
1699            .dispatch_tree
1700            .available_actions(node_id);
1701        for action_type in self.global_action_listeners.keys() {
1702            if let Err(ix) = actions.binary_search_by_key(action_type, |a| a.as_any().type_id()) {
1703                let action = self.actions.build_action_type(action_type).ok();
1704                if let Some(action) = action {
1705                    actions.insert(ix, action);
1706                }
1707            }
1708        }
1709        actions
1710    }
1711
1712    /// Returns key bindings that invoke the given action on the currently focused element.
1713    pub fn bindings_for_action(&self, action: &dyn Action) -> Vec<KeyBinding> {
1714        self.window
1715            .rendered_frame
1716            .dispatch_tree
1717            .bindings_for_action(
1718                action,
1719                &self.window.rendered_frame.dispatch_tree.context_stack,
1720            )
1721    }
1722
1723    /// Returns any bindings that would invoke the given action on the given focus handle if it were focused.
1724    pub fn bindings_for_action_in(
1725        &self,
1726        action: &dyn Action,
1727        focus_handle: &FocusHandle,
1728    ) -> Vec<KeyBinding> {
1729        let dispatch_tree = &self.window.rendered_frame.dispatch_tree;
1730
1731        let Some(node_id) = dispatch_tree.focusable_node_id(focus_handle.id) else {
1732            return vec![];
1733        };
1734        let context_stack: Vec<_> = dispatch_tree
1735            .dispatch_path(node_id)
1736            .into_iter()
1737            .filter_map(|node_id| dispatch_tree.node(node_id).context.clone())
1738            .collect();
1739        dispatch_tree.bindings_for_action(action, &context_stack)
1740    }
1741
1742    /// Returns a generic event listener that invokes the given listener with the view and context associated with the given view handle.
1743    pub fn listener_for<V: Render, E>(
1744        &self,
1745        view: &View<V>,
1746        f: impl Fn(&mut V, &E, &mut ViewContext<V>) + 'static,
1747    ) -> impl Fn(&E, &mut WindowContext) + 'static {
1748        let view = view.downgrade();
1749        move |e: &E, cx: &mut WindowContext| {
1750            view.update(cx, |view, cx| f(view, e, cx)).ok();
1751        }
1752    }
1753
1754    /// Returns a generic handler that invokes the given handler with the view and context associated with the given view handle.
1755    pub fn handler_for<V: Render>(
1756        &self,
1757        view: &View<V>,
1758        f: impl Fn(&mut V, &mut ViewContext<V>) + 'static,
1759    ) -> impl Fn(&mut WindowContext) {
1760        let view = view.downgrade();
1761        move |cx: &mut WindowContext| {
1762            view.update(cx, |view, cx| f(view, cx)).ok();
1763        }
1764    }
1765
1766    /// Register a callback that can interrupt the closing of the current window based the returned boolean.
1767    /// If the callback returns false, the window won't be closed.
1768    pub fn on_window_should_close(&mut self, f: impl Fn(&mut WindowContext) -> bool + 'static) {
1769        let mut this = self.to_async();
1770        self.window
1771            .platform_window
1772            .on_should_close(Box::new(move || this.update(|cx| f(cx)).unwrap_or(true)))
1773    }
1774
1775    /// Register an action listener on the window for the next frame. The type of action
1776    /// is determined by the first parameter of the given listener. When the next frame is rendered
1777    /// the listener will be cleared.
1778    ///
1779    /// This is a fairly low-level method, so prefer using action handlers on elements unless you have
1780    /// a specific need to register a global listener.
1781    pub fn on_action(
1782        &mut self,
1783        action_type: TypeId,
1784        listener: impl Fn(&dyn Any, DispatchPhase, &mut WindowContext) + 'static,
1785    ) {
1786        self.window
1787            .next_frame
1788            .dispatch_tree
1789            .on_action(action_type, Rc::new(listener));
1790    }
1791}
1792
1793#[cfg(target_os = "windows")]
1794impl WindowContext<'_> {
1795    /// Returns the raw HWND handle for the window.
1796    pub fn get_raw_handle(&self) -> windows::Win32::Foundation::HWND {
1797        self.window.platform_window.get_raw_handle()
1798    }
1799}
1800
1801impl Context for WindowContext<'_> {
1802    type Result<T> = T;
1803
1804    fn new_model<T>(&mut self, build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T) -> Model<T>
1805    where
1806        T: 'static,
1807    {
1808        let slot = self.app.entities.reserve();
1809        let model = build_model(&mut ModelContext::new(&mut *self.app, slot.downgrade()));
1810        self.entities.insert(slot, model)
1811    }
1812
1813    fn update_model<T: 'static, R>(
1814        &mut self,
1815        model: &Model<T>,
1816        update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
1817    ) -> R {
1818        let mut entity = self.entities.lease(model);
1819        let result = update(
1820            &mut *entity,
1821            &mut ModelContext::new(&mut *self.app, model.downgrade()),
1822        );
1823        self.entities.end_lease(entity);
1824        result
1825    }
1826
1827    fn update_window<T, F>(&mut self, window: AnyWindowHandle, update: F) -> Result<T>
1828    where
1829        F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
1830    {
1831        if window == self.window.handle {
1832            let root_view = self.window.root_view.clone().unwrap();
1833            Ok(update(root_view, self))
1834        } else {
1835            window.update(self.app, update)
1836        }
1837    }
1838
1839    fn read_model<T, R>(
1840        &self,
1841        handle: &Model<T>,
1842        read: impl FnOnce(&T, &AppContext) -> R,
1843    ) -> Self::Result<R>
1844    where
1845        T: 'static,
1846    {
1847        let entity = self.entities.read(handle);
1848        read(entity, &*self.app)
1849    }
1850
1851    fn read_window<T, R>(
1852        &self,
1853        window: &WindowHandle<T>,
1854        read: impl FnOnce(View<T>, &AppContext) -> R,
1855    ) -> Result<R>
1856    where
1857        T: 'static,
1858    {
1859        if window.any_handle == self.window.handle {
1860            let root_view = self
1861                .window
1862                .root_view
1863                .clone()
1864                .unwrap()
1865                .downcast::<T>()
1866                .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
1867            Ok(read(root_view, self))
1868        } else {
1869            self.app.read_window(window, read)
1870        }
1871    }
1872}
1873
1874impl VisualContext for WindowContext<'_> {
1875    fn new_view<V>(
1876        &mut self,
1877        build_view_state: impl FnOnce(&mut ViewContext<'_, V>) -> V,
1878    ) -> Self::Result<View<V>>
1879    where
1880        V: 'static + Render,
1881    {
1882        let slot = self.app.entities.reserve();
1883        let view = View {
1884            model: slot.clone(),
1885        };
1886        let mut cx = ViewContext::new(&mut *self.app, &mut *self.window, &view);
1887        let entity = build_view_state(&mut cx);
1888        cx.entities.insert(slot, entity);
1889
1890        // Non-generic part to avoid leaking SubscriberSet to invokers of `new_view`.
1891        fn notify_observers(cx: &mut WindowContext, tid: TypeId, view: AnyView) {
1892            cx.new_view_observers.clone().retain(&tid, |observer| {
1893                let any_view = view.clone();
1894                (observer)(any_view, cx);
1895                true
1896            });
1897        }
1898        notify_observers(self, TypeId::of::<V>(), AnyView::from(view.clone()));
1899
1900        view
1901    }
1902
1903    /// Updates the given view. Prefer calling [`View::update`] instead, which calls this method.
1904    fn update_view<T: 'static, R>(
1905        &mut self,
1906        view: &View<T>,
1907        update: impl FnOnce(&mut T, &mut ViewContext<'_, T>) -> R,
1908    ) -> Self::Result<R> {
1909        let mut lease = self.app.entities.lease(&view.model);
1910        let mut cx = ViewContext::new(&mut *self.app, &mut *self.window, view);
1911        let result = update(&mut *lease, &mut cx);
1912        cx.app.entities.end_lease(lease);
1913        result
1914    }
1915
1916    fn replace_root_view<V>(
1917        &mut self,
1918        build_view: impl FnOnce(&mut ViewContext<'_, V>) -> V,
1919    ) -> Self::Result<View<V>>
1920    where
1921        V: 'static + Render,
1922    {
1923        let view = self.new_view(build_view);
1924        self.window.root_view = Some(view.clone().into());
1925        self.refresh();
1926        view
1927    }
1928
1929    fn focus_view<V: crate::FocusableView>(&mut self, view: &View<V>) -> Self::Result<()> {
1930        self.update_view(view, |view, cx| {
1931            view.focus_handle(cx).clone().focus(cx);
1932        })
1933    }
1934
1935    fn dismiss_view<V>(&mut self, view: &View<V>) -> Self::Result<()>
1936    where
1937        V: ManagedView,
1938    {
1939        self.update_view(view, |_, cx| cx.emit(DismissEvent))
1940    }
1941}
1942
1943impl<'a> std::ops::Deref for WindowContext<'a> {
1944    type Target = AppContext;
1945
1946    fn deref(&self) -> &Self::Target {
1947        self.app
1948    }
1949}
1950
1951impl<'a> std::ops::DerefMut for WindowContext<'a> {
1952    fn deref_mut(&mut self) -> &mut Self::Target {
1953        self.app
1954    }
1955}
1956
1957impl<'a> Borrow<AppContext> for WindowContext<'a> {
1958    fn borrow(&self) -> &AppContext {
1959        self.app
1960    }
1961}
1962
1963impl<'a> BorrowMut<AppContext> for WindowContext<'a> {
1964    fn borrow_mut(&mut self) -> &mut AppContext {
1965        self.app
1966    }
1967}
1968
1969/// This trait contains functionality that is shared across [`ViewContext`] and [`WindowContext`]
1970pub trait BorrowWindow: BorrowMut<Window> + BorrowMut<AppContext> {
1971    #[doc(hidden)]
1972    fn app_mut(&mut self) -> &mut AppContext {
1973        self.borrow_mut()
1974    }
1975
1976    #[doc(hidden)]
1977    fn app(&self) -> &AppContext {
1978        self.borrow()
1979    }
1980
1981    #[doc(hidden)]
1982    fn window(&self) -> &Window {
1983        self.borrow()
1984    }
1985
1986    #[doc(hidden)]
1987    fn window_mut(&mut self) -> &mut Window {
1988        self.borrow_mut()
1989    }
1990}
1991
1992impl Borrow<Window> for WindowContext<'_> {
1993    fn borrow(&self) -> &Window {
1994        self.window
1995    }
1996}
1997
1998impl BorrowMut<Window> for WindowContext<'_> {
1999    fn borrow_mut(&mut self) -> &mut Window {
2000        self.window
2001    }
2002}
2003
2004impl<T> BorrowWindow for T where T: BorrowMut<AppContext> + BorrowMut<Window> {}
2005
2006/// Provides access to application state that is specialized for a particular [`View`].
2007/// Allows you to interact with focus, emit events, etc.
2008/// ViewContext also derefs to [`WindowContext`], giving you access to all of its methods as well.
2009/// When you call [`View::update`], you're passed a `&mut V` and an `&mut ViewContext<V>`.
2010pub struct ViewContext<'a, V> {
2011    window_cx: WindowContext<'a>,
2012    view: &'a View<V>,
2013}
2014
2015impl<V> Borrow<AppContext> for ViewContext<'_, V> {
2016    fn borrow(&self) -> &AppContext {
2017        &*self.window_cx.app
2018    }
2019}
2020
2021impl<V> BorrowMut<AppContext> for ViewContext<'_, V> {
2022    fn borrow_mut(&mut self) -> &mut AppContext {
2023        &mut *self.window_cx.app
2024    }
2025}
2026
2027impl<V> Borrow<Window> for ViewContext<'_, V> {
2028    fn borrow(&self) -> &Window {
2029        &*self.window_cx.window
2030    }
2031}
2032
2033impl<V> BorrowMut<Window> for ViewContext<'_, V> {
2034    fn borrow_mut(&mut self) -> &mut Window {
2035        &mut *self.window_cx.window
2036    }
2037}
2038
2039impl<'a, V: 'static> ViewContext<'a, V> {
2040    pub(crate) fn new(app: &'a mut AppContext, window: &'a mut Window, view: &'a View<V>) -> Self {
2041        Self {
2042            window_cx: WindowContext::new(app, window),
2043            view,
2044        }
2045    }
2046
2047    /// Get the entity_id of this view.
2048    pub fn entity_id(&self) -> EntityId {
2049        self.view.entity_id()
2050    }
2051
2052    /// Get the view pointer underlying this context.
2053    pub fn view(&self) -> &View<V> {
2054        self.view
2055    }
2056
2057    /// Get the model underlying this view.
2058    pub fn model(&self) -> &Model<V> {
2059        &self.view.model
2060    }
2061
2062    /// Access the underlying window context.
2063    pub fn window_context(&mut self) -> &mut WindowContext<'a> {
2064        &mut self.window_cx
2065    }
2066
2067    /// Sets a given callback to be run on the next frame.
2068    pub fn on_next_frame(&mut self, f: impl FnOnce(&mut V, &mut ViewContext<V>) + 'static)
2069    where
2070        V: 'static,
2071    {
2072        let view = self.view().clone();
2073        self.window_cx.on_next_frame(move |cx| view.update(cx, f));
2074    }
2075
2076    /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
2077    /// that are currently on the stack to be returned to the app.
2078    pub fn defer(&mut self, f: impl FnOnce(&mut V, &mut ViewContext<V>) + 'static) {
2079        let view = self.view().downgrade();
2080        self.window_cx.defer(move |cx| {
2081            view.update(cx, f).ok();
2082        });
2083    }
2084
2085    /// Observe another model or view for changes to its state, as tracked by [`ModelContext::notify`].
2086    pub fn observe<V2, E>(
2087        &mut self,
2088        entity: &E,
2089        mut on_notify: impl FnMut(&mut V, E, &mut ViewContext<'_, V>) + 'static,
2090    ) -> Subscription
2091    where
2092        V2: 'static,
2093        V: 'static,
2094        E: Entity<V2>,
2095    {
2096        let view = self.view().downgrade();
2097        let entity_id = entity.entity_id();
2098        let entity = entity.downgrade();
2099        let window_handle = self.window.handle;
2100        self.app.new_observer(
2101            entity_id,
2102            Box::new(move |cx| {
2103                window_handle
2104                    .update(cx, |_, cx| {
2105                        if let Some(handle) = E::upgrade_from(&entity) {
2106                            view.update(cx, |this, cx| on_notify(this, handle, cx))
2107                                .is_ok()
2108                        } else {
2109                            false
2110                        }
2111                    })
2112                    .unwrap_or(false)
2113            }),
2114        )
2115    }
2116
2117    /// Subscribe to events emitted by another model or view.
2118    /// The entity to which you're subscribing must implement the [`EventEmitter`] trait.
2119    /// The callback will be invoked with a reference to the current view, a handle to the emitting entity (either a [`View`] or [`Model`]), the event, and a view context for the current view.
2120    pub fn subscribe<V2, E, Evt>(
2121        &mut self,
2122        entity: &E,
2123        mut on_event: impl FnMut(&mut V, E, &Evt, &mut ViewContext<'_, V>) + 'static,
2124    ) -> Subscription
2125    where
2126        V2: EventEmitter<Evt>,
2127        E: Entity<V2>,
2128        Evt: 'static,
2129    {
2130        let view = self.view().downgrade();
2131        let entity_id = entity.entity_id();
2132        let handle = entity.downgrade();
2133        let window_handle = self.window.handle;
2134        self.app.new_subscription(
2135            entity_id,
2136            (
2137                TypeId::of::<Evt>(),
2138                Box::new(move |event, cx| {
2139                    window_handle
2140                        .update(cx, |_, cx| {
2141                            if let Some(handle) = E::upgrade_from(&handle) {
2142                                let event = event.downcast_ref().expect("invalid event type");
2143                                view.update(cx, |this, cx| on_event(this, handle, event, cx))
2144                                    .is_ok()
2145                            } else {
2146                                false
2147                            }
2148                        })
2149                        .unwrap_or(false)
2150                }),
2151            ),
2152        )
2153    }
2154
2155    /// Register a callback to be invoked when the view is released.
2156    ///
2157    /// The callback receives a handle to the view's window. This handle may be
2158    /// invalid, if the window was closed before the view was released.
2159    pub fn on_release(
2160        &mut self,
2161        on_release: impl FnOnce(&mut V, AnyWindowHandle, &mut AppContext) + 'static,
2162    ) -> Subscription {
2163        let window_handle = self.window.handle;
2164        let (subscription, activate) = self.app.release_listeners.insert(
2165            self.view.model.entity_id,
2166            Box::new(move |this, cx| {
2167                let this = this.downcast_mut().expect("invalid entity type");
2168                on_release(this, window_handle, cx)
2169            }),
2170        );
2171        activate();
2172        subscription
2173    }
2174
2175    /// Register a callback to be invoked when the given Model or View is released.
2176    pub fn observe_release<V2, E>(
2177        &mut self,
2178        entity: &E,
2179        mut on_release: impl FnMut(&mut V, &mut V2, &mut ViewContext<'_, V>) + 'static,
2180    ) -> Subscription
2181    where
2182        V: 'static,
2183        V2: 'static,
2184        E: Entity<V2>,
2185    {
2186        let view = self.view().downgrade();
2187        let entity_id = entity.entity_id();
2188        let window_handle = self.window.handle;
2189        let (subscription, activate) = self.app.release_listeners.insert(
2190            entity_id,
2191            Box::new(move |entity, cx| {
2192                let entity = entity.downcast_mut().expect("invalid entity type");
2193                let _ = window_handle.update(cx, |_, cx| {
2194                    view.update(cx, |this, cx| on_release(this, entity, cx))
2195                });
2196            }),
2197        );
2198        activate();
2199        subscription
2200    }
2201
2202    /// Indicate that this view has changed, which will invoke any observers and also mark the window as dirty.
2203    /// If this view or any of its ancestors are *cached*, notifying it will cause it or its ancestors to be redrawn.
2204    pub fn notify(&mut self) {
2205        self.window_cx.notify(self.view.entity_id());
2206    }
2207
2208    /// Register a callback to be invoked when the window is resized.
2209    pub fn observe_window_bounds(
2210        &mut self,
2211        mut callback: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2212    ) -> Subscription {
2213        let view = self.view.downgrade();
2214        let (subscription, activate) = self.window.bounds_observers.insert(
2215            (),
2216            Box::new(move |cx| view.update(cx, |view, cx| callback(view, cx)).is_ok()),
2217        );
2218        activate();
2219        subscription
2220    }
2221
2222    /// Register a callback to be invoked when the window is activated or deactivated.
2223    pub fn observe_window_activation(
2224        &mut self,
2225        mut callback: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2226    ) -> Subscription {
2227        let view = self.view.downgrade();
2228        let (subscription, activate) = self.window.activation_observers.insert(
2229            (),
2230            Box::new(move |cx| view.update(cx, |view, cx| callback(view, cx)).is_ok()),
2231        );
2232        activate();
2233        subscription
2234    }
2235
2236    /// Registers a callback to be invoked when the window appearance changes.
2237    pub fn observe_window_appearance(
2238        &mut self,
2239        mut callback: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2240    ) -> Subscription {
2241        let view = self.view.downgrade();
2242        let (subscription, activate) = self.window.appearance_observers.insert(
2243            (),
2244            Box::new(move |cx| view.update(cx, |view, cx| callback(view, cx)).is_ok()),
2245        );
2246        activate();
2247        subscription
2248    }
2249
2250    /// Register a listener to be called when the given focus handle receives focus.
2251    /// Returns a subscription and persists until the subscription is dropped.
2252    pub fn on_focus(
2253        &mut self,
2254        handle: &FocusHandle,
2255        mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2256    ) -> Subscription {
2257        let view = self.view.downgrade();
2258        let focus_id = handle.id;
2259        let (subscription, activate) =
2260            self.window.new_focus_listener(Box::new(move |event, cx| {
2261                view.update(cx, |view, cx| {
2262                    if event.previous_focus_path.last() != Some(&focus_id)
2263                        && event.current_focus_path.last() == Some(&focus_id)
2264                    {
2265                        listener(view, cx)
2266                    }
2267                })
2268                .is_ok()
2269            }));
2270        self.app.defer(|_| activate());
2271        subscription
2272    }
2273
2274    /// Register a listener to be called when the given focus handle or one of its descendants receives focus.
2275    /// Returns a subscription and persists until the subscription is dropped.
2276    pub fn on_focus_in(
2277        &mut self,
2278        handle: &FocusHandle,
2279        mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2280    ) -> Subscription {
2281        let view = self.view.downgrade();
2282        let focus_id = handle.id;
2283        let (subscription, activate) =
2284            self.window.new_focus_listener(Box::new(move |event, cx| {
2285                view.update(cx, |view, cx| {
2286                    if !event.previous_focus_path.contains(&focus_id)
2287                        && event.current_focus_path.contains(&focus_id)
2288                    {
2289                        listener(view, cx)
2290                    }
2291                })
2292                .is_ok()
2293            }));
2294        self.app.defer(move |_| activate());
2295        subscription
2296    }
2297
2298    /// Register a listener to be called when the given focus handle loses focus.
2299    /// Returns a subscription and persists until the subscription is dropped.
2300    pub fn on_blur(
2301        &mut self,
2302        handle: &FocusHandle,
2303        mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2304    ) -> Subscription {
2305        let view = self.view.downgrade();
2306        let focus_id = handle.id;
2307        let (subscription, activate) =
2308            self.window.new_focus_listener(Box::new(move |event, cx| {
2309                view.update(cx, |view, cx| {
2310                    if event.previous_focus_path.last() == Some(&focus_id)
2311                        && event.current_focus_path.last() != Some(&focus_id)
2312                    {
2313                        listener(view, cx)
2314                    }
2315                })
2316                .is_ok()
2317            }));
2318        self.app.defer(move |_| activate());
2319        subscription
2320    }
2321
2322    /// Register a listener to be called when nothing in the window has focus.
2323    /// This typically happens when the node that was focused is removed from the tree,
2324    /// and this callback lets you chose a default place to restore the users focus.
2325    /// Returns a subscription and persists until the subscription is dropped.
2326    pub fn on_focus_lost(
2327        &mut self,
2328        mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2329    ) -> Subscription {
2330        let view = self.view.downgrade();
2331        let (subscription, activate) = self.window.focus_lost_listeners.insert(
2332            (),
2333            Box::new(move |cx| view.update(cx, |view, cx| listener(view, cx)).is_ok()),
2334        );
2335        activate();
2336        subscription
2337    }
2338
2339    /// Register a listener to be called when the given focus handle or one of its descendants loses focus.
2340    /// Returns a subscription and persists until the subscription is dropped.
2341    pub fn on_focus_out(
2342        &mut self,
2343        handle: &FocusHandle,
2344        mut listener: impl FnMut(&mut V, &mut ViewContext<V>) + 'static,
2345    ) -> Subscription {
2346        let view = self.view.downgrade();
2347        let focus_id = handle.id;
2348        let (subscription, activate) =
2349            self.window.new_focus_listener(Box::new(move |event, cx| {
2350                view.update(cx, |view, cx| {
2351                    if event.previous_focus_path.contains(&focus_id)
2352                        && !event.current_focus_path.contains(&focus_id)
2353                    {
2354                        listener(view, cx)
2355                    }
2356                })
2357                .is_ok()
2358            }));
2359        self.app.defer(move |_| activate());
2360        subscription
2361    }
2362
2363    /// Schedule a future to be run asynchronously.
2364    /// The given callback is invoked with a [`WeakView<V>`] to avoid leaking the view for a long-running process.
2365    /// It's also given an [`AsyncWindowContext`], which can be used to access the state of the view across await points.
2366    /// The returned future will be polled on the main thread.
2367    pub fn spawn<Fut, R>(
2368        &mut self,
2369        f: impl FnOnce(WeakView<V>, AsyncWindowContext) -> Fut,
2370    ) -> Task<R>
2371    where
2372        R: 'static,
2373        Fut: Future<Output = R> + 'static,
2374    {
2375        let view = self.view().downgrade();
2376        self.window_cx.spawn(|cx| f(view, cx))
2377    }
2378
2379    /// Register a callback to be invoked when the given global state changes.
2380    pub fn observe_global<G: Global>(
2381        &mut self,
2382        mut f: impl FnMut(&mut V, &mut ViewContext<'_, V>) + 'static,
2383    ) -> Subscription {
2384        let window_handle = self.window.handle;
2385        let view = self.view().downgrade();
2386        let (subscription, activate) = self.global_observers.insert(
2387            TypeId::of::<G>(),
2388            Box::new(move |cx| {
2389                window_handle
2390                    .update(cx, |_, cx| view.update(cx, |view, cx| f(view, cx)).is_ok())
2391                    .unwrap_or(false)
2392            }),
2393        );
2394        self.app.defer(move |_| activate());
2395        subscription
2396    }
2397
2398    /// Register a callback to be invoked when the given Action type is dispatched to the window.
2399    pub fn on_action(
2400        &mut self,
2401        action_type: TypeId,
2402        listener: impl Fn(&mut V, &dyn Any, DispatchPhase, &mut ViewContext<V>) + 'static,
2403    ) {
2404        let handle = self.view().clone();
2405        self.window_cx
2406            .on_action(action_type, move |action, phase, cx| {
2407                handle.update(cx, |view, cx| {
2408                    listener(view, action, phase, cx);
2409                })
2410            });
2411    }
2412
2413    /// Emit an event to be handled any other views that have subscribed via [ViewContext::subscribe].
2414    pub fn emit<Evt>(&mut self, event: Evt)
2415    where
2416        Evt: 'static,
2417        V: EventEmitter<Evt>,
2418    {
2419        let emitter = self.view.model.entity_id;
2420        self.app.push_effect(Effect::Emit {
2421            emitter,
2422            event_type: TypeId::of::<Evt>(),
2423            event: Box::new(event),
2424        });
2425    }
2426
2427    /// Move focus to the current view, assuming it implements [`FocusableView`].
2428    pub fn focus_self(&mut self)
2429    where
2430        V: FocusableView,
2431    {
2432        self.defer(|view, cx| view.focus_handle(cx).focus(cx))
2433    }
2434
2435    /// Convenience method for accessing view state in an event callback.
2436    ///
2437    /// Many GPUI callbacks take the form of `Fn(&E, &mut WindowContext)`,
2438    /// but it's often useful to be able to access view state in these
2439    /// callbacks. This method provides a convenient way to do so.
2440    pub fn listener<E>(
2441        &self,
2442        f: impl Fn(&mut V, &E, &mut ViewContext<V>) + 'static,
2443    ) -> impl Fn(&E, &mut WindowContext) + 'static {
2444        let view = self.view().downgrade();
2445        move |e: &E, cx: &mut WindowContext| {
2446            view.update(cx, |view, cx| f(view, e, cx)).ok();
2447        }
2448    }
2449}
2450
2451impl<V> Context for ViewContext<'_, V> {
2452    type Result<U> = U;
2453
2454    fn new_model<T: 'static>(
2455        &mut self,
2456        build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
2457    ) -> Model<T> {
2458        self.window_cx.new_model(build_model)
2459    }
2460
2461    fn update_model<T: 'static, R>(
2462        &mut self,
2463        model: &Model<T>,
2464        update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
2465    ) -> R {
2466        self.window_cx.update_model(model, update)
2467    }
2468
2469    fn update_window<T, F>(&mut self, window: AnyWindowHandle, update: F) -> Result<T>
2470    where
2471        F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
2472    {
2473        self.window_cx.update_window(window, update)
2474    }
2475
2476    fn read_model<T, R>(
2477        &self,
2478        handle: &Model<T>,
2479        read: impl FnOnce(&T, &AppContext) -> R,
2480    ) -> Self::Result<R>
2481    where
2482        T: 'static,
2483    {
2484        self.window_cx.read_model(handle, read)
2485    }
2486
2487    fn read_window<T, R>(
2488        &self,
2489        window: &WindowHandle<T>,
2490        read: impl FnOnce(View<T>, &AppContext) -> R,
2491    ) -> Result<R>
2492    where
2493        T: 'static,
2494    {
2495        self.window_cx.read_window(window, read)
2496    }
2497}
2498
2499impl<V: 'static> VisualContext for ViewContext<'_, V> {
2500    fn new_view<W: Render + 'static>(
2501        &mut self,
2502        build_view_state: impl FnOnce(&mut ViewContext<'_, W>) -> W,
2503    ) -> Self::Result<View<W>> {
2504        self.window_cx.new_view(build_view_state)
2505    }
2506
2507    fn update_view<V2: 'static, R>(
2508        &mut self,
2509        view: &View<V2>,
2510        update: impl FnOnce(&mut V2, &mut ViewContext<'_, V2>) -> R,
2511    ) -> Self::Result<R> {
2512        self.window_cx.update_view(view, update)
2513    }
2514
2515    fn replace_root_view<W>(
2516        &mut self,
2517        build_view: impl FnOnce(&mut ViewContext<'_, W>) -> W,
2518    ) -> Self::Result<View<W>>
2519    where
2520        W: 'static + Render,
2521    {
2522        self.window_cx.replace_root_view(build_view)
2523    }
2524
2525    fn focus_view<W: FocusableView>(&mut self, view: &View<W>) -> Self::Result<()> {
2526        self.window_cx.focus_view(view)
2527    }
2528
2529    fn dismiss_view<W: ManagedView>(&mut self, view: &View<W>) -> Self::Result<()> {
2530        self.window_cx.dismiss_view(view)
2531    }
2532}
2533
2534impl<'a, V> std::ops::Deref for ViewContext<'a, V> {
2535    type Target = WindowContext<'a>;
2536
2537    fn deref(&self) -> &Self::Target {
2538        &self.window_cx
2539    }
2540}
2541
2542impl<'a, V> std::ops::DerefMut for ViewContext<'a, V> {
2543    fn deref_mut(&mut self) -> &mut Self::Target {
2544        &mut self.window_cx
2545    }
2546}
2547
2548// #[derive(Clone, Copy, Eq, PartialEq, Hash)]
2549slotmap::new_key_type! {
2550    /// A unique identifier for a window.
2551    pub struct WindowId;
2552}
2553
2554impl WindowId {
2555    /// Converts this window ID to a `u64`.
2556    pub fn as_u64(&self) -> u64 {
2557        self.0.as_ffi()
2558    }
2559}
2560
2561/// A handle to a window with a specific root view type.
2562/// Note that this does not keep the window alive on its own.
2563#[derive(Deref, DerefMut)]
2564pub struct WindowHandle<V> {
2565    #[deref]
2566    #[deref_mut]
2567    pub(crate) any_handle: AnyWindowHandle,
2568    state_type: PhantomData<V>,
2569}
2570
2571impl<V: 'static + Render> WindowHandle<V> {
2572    /// Creates a new handle from a window ID.
2573    /// This does not check if the root type of the window is `V`.
2574    pub fn new(id: WindowId) -> Self {
2575        WindowHandle {
2576            any_handle: AnyWindowHandle {
2577                id,
2578                state_type: TypeId::of::<V>(),
2579            },
2580            state_type: PhantomData,
2581        }
2582    }
2583
2584    /// Get the root view out of this window.
2585    ///
2586    /// This will fail if the window is closed or if the root view's type does not match `V`.
2587    pub fn root<C>(&self, cx: &mut C) -> Result<View<V>>
2588    where
2589        C: Context,
2590    {
2591        Flatten::flatten(cx.update_window(self.any_handle, |root_view, _| {
2592            root_view
2593                .downcast::<V>()
2594                .map_err(|_| anyhow!("the type of the window's root view has changed"))
2595        }))
2596    }
2597
2598    /// Updates the root view of this window.
2599    ///
2600    /// This will fail if the window has been closed or if the root view's type does not match
2601    pub fn update<C, R>(
2602        &self,
2603        cx: &mut C,
2604        update: impl FnOnce(&mut V, &mut ViewContext<'_, V>) -> R,
2605    ) -> Result<R>
2606    where
2607        C: Context,
2608    {
2609        cx.update_window(self.any_handle, |root_view, cx| {
2610            let view = root_view
2611                .downcast::<V>()
2612                .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
2613            Ok(cx.update_view(&view, update))
2614        })?
2615    }
2616
2617    /// Read the root view out of this window.
2618    ///
2619    /// This will fail if the window is closed or if the root view's type does not match `V`.
2620    pub fn read<'a>(&self, cx: &'a AppContext) -> Result<&'a V> {
2621        let x = cx
2622            .windows
2623            .get(self.id)
2624            .and_then(|window| {
2625                window
2626                    .as_ref()
2627                    .and_then(|window| window.root_view.clone())
2628                    .map(|root_view| root_view.downcast::<V>())
2629            })
2630            .ok_or_else(|| anyhow!("window not found"))?
2631            .map_err(|_| anyhow!("the type of the window's root view has changed"))?;
2632
2633        Ok(x.read(cx))
2634    }
2635
2636    /// Read the root view out of this window, with a callback
2637    ///
2638    /// This will fail if the window is closed or if the root view's type does not match `V`.
2639    pub fn read_with<C, R>(&self, cx: &C, read_with: impl FnOnce(&V, &AppContext) -> R) -> Result<R>
2640    where
2641        C: Context,
2642    {
2643        cx.read_window(self, |root_view, cx| read_with(root_view.read(cx), cx))
2644    }
2645
2646    /// Read the root view pointer off of this window.
2647    ///
2648    /// This will fail if the window is closed or if the root view's type does not match `V`.
2649    pub fn root_view<C>(&self, cx: &C) -> Result<View<V>>
2650    where
2651        C: Context,
2652    {
2653        cx.read_window(self, |root_view, _cx| root_view.clone())
2654    }
2655
2656    /// Check if this window is 'active'.
2657    ///
2658    /// Will return `None` if the window is closed or currently
2659    /// borrowed.
2660    pub fn is_active(&self, cx: &mut AppContext) -> Option<bool> {
2661        cx.update_window(self.any_handle, |_, cx| cx.is_window_active())
2662            .ok()
2663    }
2664}
2665
2666impl<V> Copy for WindowHandle<V> {}
2667
2668impl<V> Clone for WindowHandle<V> {
2669    fn clone(&self) -> Self {
2670        *self
2671    }
2672}
2673
2674impl<V> PartialEq for WindowHandle<V> {
2675    fn eq(&self, other: &Self) -> bool {
2676        self.any_handle == other.any_handle
2677    }
2678}
2679
2680impl<V> Eq for WindowHandle<V> {}
2681
2682impl<V> Hash for WindowHandle<V> {
2683    fn hash<H: Hasher>(&self, state: &mut H) {
2684        self.any_handle.hash(state);
2685    }
2686}
2687
2688impl<V: 'static> From<WindowHandle<V>> for AnyWindowHandle {
2689    fn from(val: WindowHandle<V>) -> Self {
2690        val.any_handle
2691    }
2692}
2693
2694/// A handle to a window with any root view type, which can be downcast to a window with a specific root view type.
2695#[derive(Copy, Clone, PartialEq, Eq, Hash)]
2696pub struct AnyWindowHandle {
2697    pub(crate) id: WindowId,
2698    state_type: TypeId,
2699}
2700
2701impl AnyWindowHandle {
2702    /// Get the ID of this window.
2703    pub fn window_id(&self) -> WindowId {
2704        self.id
2705    }
2706
2707    /// Attempt to convert this handle to a window handle with a specific root view type.
2708    /// If the types do not match, this will return `None`.
2709    pub fn downcast<T: 'static>(&self) -> Option<WindowHandle<T>> {
2710        if TypeId::of::<T>() == self.state_type {
2711            Some(WindowHandle {
2712                any_handle: *self,
2713                state_type: PhantomData,
2714            })
2715        } else {
2716            None
2717        }
2718    }
2719
2720    /// Updates the state of the root view of this window.
2721    ///
2722    /// This will fail if the window has been closed.
2723    pub fn update<C, R>(
2724        self,
2725        cx: &mut C,
2726        update: impl FnOnce(AnyView, &mut WindowContext<'_>) -> R,
2727    ) -> Result<R>
2728    where
2729        C: Context,
2730    {
2731        cx.update_window(self, update)
2732    }
2733
2734    /// Read the state of the root view of this window.
2735    ///
2736    /// This will fail if the window has been closed.
2737    pub fn read<T, C, R>(self, cx: &C, read: impl FnOnce(View<T>, &AppContext) -> R) -> Result<R>
2738    where
2739        C: Context,
2740        T: 'static,
2741    {
2742        let view = self
2743            .downcast::<T>()
2744            .context("the type of the window's root view has changed")?;
2745
2746        cx.read_window(&view, read)
2747    }
2748}
2749
2750/// An identifier for an [`Element`](crate::Element).
2751///
2752/// Can be constructed with a string, a number, or both, as well
2753/// as other internal representations.
2754#[derive(Clone, Debug, Eq, PartialEq, Hash)]
2755pub enum ElementId {
2756    /// The ID of a View element
2757    View(EntityId),
2758    /// An integer ID.
2759    Integer(usize),
2760    /// A string based ID.
2761    Name(SharedString),
2762    /// An ID that's equated with a focus handle.
2763    FocusHandle(FocusId),
2764    /// A combination of a name and an integer.
2765    NamedInteger(SharedString, usize),
2766}
2767
2768impl Display for ElementId {
2769    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
2770        match self {
2771            ElementId::View(entity_id) => write!(f, "view-{}", entity_id)?,
2772            ElementId::Integer(ix) => write!(f, "{}", ix)?,
2773            ElementId::Name(name) => write!(f, "{}", name)?,
2774            ElementId::FocusHandle(_) => write!(f, "FocusHandle")?,
2775            ElementId::NamedInteger(s, i) => write!(f, "{}-{}", s, i)?,
2776        }
2777
2778        Ok(())
2779    }
2780}
2781
2782impl TryInto<SharedString> for ElementId {
2783    type Error = anyhow::Error;
2784
2785    fn try_into(self) -> anyhow::Result<SharedString> {
2786        if let ElementId::Name(name) = self {
2787            Ok(name)
2788        } else {
2789            Err(anyhow!("element id is not string"))
2790        }
2791    }
2792}
2793
2794impl From<usize> for ElementId {
2795    fn from(id: usize) -> Self {
2796        ElementId::Integer(id)
2797    }
2798}
2799
2800impl From<i32> for ElementId {
2801    fn from(id: i32) -> Self {
2802        Self::Integer(id as usize)
2803    }
2804}
2805
2806impl From<SharedString> for ElementId {
2807    fn from(name: SharedString) -> Self {
2808        ElementId::Name(name)
2809    }
2810}
2811
2812impl From<&'static str> for ElementId {
2813    fn from(name: &'static str) -> Self {
2814        ElementId::Name(name.into())
2815    }
2816}
2817
2818impl<'a> From<&'a FocusHandle> for ElementId {
2819    fn from(handle: &'a FocusHandle) -> Self {
2820        ElementId::FocusHandle(handle.id)
2821    }
2822}
2823
2824impl From<(&'static str, EntityId)> for ElementId {
2825    fn from((name, id): (&'static str, EntityId)) -> Self {
2826        ElementId::NamedInteger(name.into(), id.as_u64() as usize)
2827    }
2828}
2829
2830impl From<(&'static str, usize)> for ElementId {
2831    fn from((name, id): (&'static str, usize)) -> Self {
2832        ElementId::NamedInteger(name.into(), id)
2833    }
2834}
2835
2836impl From<(&'static str, u64)> for ElementId {
2837    fn from((name, id): (&'static str, u64)) -> Self {
2838        ElementId::NamedInteger(name.into(), id as usize)
2839    }
2840}
2841
2842/// A rectangle to be rendered in the window at the given position and size.
2843/// Passed as an argument [`ElementContext::paint_quad`].
2844#[derive(Clone)]
2845pub struct PaintQuad {
2846    bounds: Bounds<Pixels>,
2847    corner_radii: Corners<Pixels>,
2848    background: Hsla,
2849    border_widths: Edges<Pixels>,
2850    border_color: Hsla,
2851}
2852
2853impl PaintQuad {
2854    /// Sets the corner radii of the quad.
2855    pub fn corner_radii(self, corner_radii: impl Into<Corners<Pixels>>) -> Self {
2856        PaintQuad {
2857            corner_radii: corner_radii.into(),
2858            ..self
2859        }
2860    }
2861
2862    /// Sets the border widths of the quad.
2863    pub fn border_widths(self, border_widths: impl Into<Edges<Pixels>>) -> Self {
2864        PaintQuad {
2865            border_widths: border_widths.into(),
2866            ..self
2867        }
2868    }
2869
2870    /// Sets the border color of the quad.
2871    pub fn border_color(self, border_color: impl Into<Hsla>) -> Self {
2872        PaintQuad {
2873            border_color: border_color.into(),
2874            ..self
2875        }
2876    }
2877
2878    /// Sets the background color of the quad.
2879    pub fn background(self, background: impl Into<Hsla>) -> Self {
2880        PaintQuad {
2881            background: background.into(),
2882            ..self
2883        }
2884    }
2885}
2886
2887/// Creates a quad with the given parameters.
2888pub fn quad(
2889    bounds: Bounds<Pixels>,
2890    corner_radii: impl Into<Corners<Pixels>>,
2891    background: impl Into<Hsla>,
2892    border_widths: impl Into<Edges<Pixels>>,
2893    border_color: impl Into<Hsla>,
2894) -> PaintQuad {
2895    PaintQuad {
2896        bounds,
2897        corner_radii: corner_radii.into(),
2898        background: background.into(),
2899        border_widths: border_widths.into(),
2900        border_color: border_color.into(),
2901    }
2902}
2903
2904/// Creates a filled quad with the given bounds and background color.
2905pub fn fill(bounds: impl Into<Bounds<Pixels>>, background: impl Into<Hsla>) -> PaintQuad {
2906    PaintQuad {
2907        bounds: bounds.into(),
2908        corner_radii: (0.).into(),
2909        background: background.into(),
2910        border_widths: (0.).into(),
2911        border_color: transparent_black(),
2912    }
2913}
2914
2915/// Creates a rectangle outline with the given bounds, border color, and a 1px border width
2916pub fn outline(bounds: impl Into<Bounds<Pixels>>, border_color: impl Into<Hsla>) -> PaintQuad {
2917    PaintQuad {
2918        bounds: bounds.into(),
2919        corner_radii: (0.).into(),
2920        background: transparent_black(),
2921        border_widths: (1.).into(),
2922        border_color: border_color.into(),
2923    }
2924}