window.rs

   1use crate::{
   2    elements::AnyRootElement,
   3    geometry::rect::RectF,
   4    json::ToJson,
   5    keymap_matcher::{Binding, KeymapContext, Keystroke, MatchResult},
   6    platform::{
   7        self, Appearance, CursorStyle, Event, KeyDownEvent, KeyUpEvent, ModifiersChangedEvent,
   8        MouseButton, MouseMovedEvent, PromptLevel, WindowBounds,
   9    },
  10    scene::{
  11        CursorRegion, MouseClick, MouseClickOut, MouseDown, MouseDownOut, MouseDrag, MouseEvent,
  12        MouseHover, MouseMove, MouseMoveOut, MouseScrollWheel, MouseUp, MouseUpOut, Scene,
  13    },
  14    text_layout::TextLayoutCache,
  15    util::post_inc,
  16    Action, AnyView, AnyViewHandle, AnyWindowHandle, AppContext, BorrowAppContext,
  17    BorrowWindowContext, Effect, Element, Entity, Handle, LayoutContext, MouseRegion,
  18    MouseRegionId, PaintContext, SceneBuilder, Subscription, View, ViewContext, ViewHandle,
  19    WindowInvalidation,
  20};
  21use anyhow::{anyhow, bail, Result};
  22use collections::{HashMap, HashSet};
  23use pathfinder_geometry::vector::{vec2f, Vector2F};
  24use postage::oneshot;
  25use serde_json::json;
  26use smallvec::SmallVec;
  27use sqlez::{
  28    bindable::{Bind, Column, StaticColumnCount},
  29    statement::Statement,
  30};
  31use std::{
  32    any::TypeId,
  33    mem,
  34    ops::{Deref, DerefMut, Range, Sub},
  35};
  36use taffy::Taffy;
  37use util::ResultExt;
  38use uuid::Uuid;
  39
  40use super::{Reference, ViewMetadata};
  41
  42pub struct Window {
  43    layout_engine: Taffy,
  44    pub(crate) root_view: Option<AnyViewHandle>,
  45    pub(crate) focused_view_id: Option<usize>,
  46    pub(crate) parents: HashMap<usize, usize>,
  47    pub(crate) is_active: bool,
  48    pub(crate) is_fullscreen: bool,
  49    pub(crate) invalidation: Option<WindowInvalidation>,
  50    pub(crate) platform_window: Box<dyn platform::Window>,
  51    pub(crate) rendered_views: HashMap<usize, Box<dyn AnyRootElement>>,
  52    titlebar_height: f32,
  53    appearance: Appearance,
  54    cursor_regions: Vec<CursorRegion>,
  55    mouse_regions: Vec<(MouseRegion, usize)>,
  56    last_mouse_moved_event: Option<Event>,
  57    pub(crate) hovered_region_ids: HashSet<MouseRegionId>,
  58    pub(crate) clicked_region_ids: HashSet<MouseRegionId>,
  59    pub(crate) clicked_region: Option<(MouseRegionId, MouseButton)>,
  60    mouse_position: Vector2F,
  61    text_layout_cache: TextLayoutCache,
  62}
  63
  64impl Window {
  65    pub fn new<V, F>(
  66        handle: AnyWindowHandle,
  67        platform_window: Box<dyn platform::Window>,
  68        cx: &mut AppContext,
  69        build_view: F,
  70    ) -> Self
  71    where
  72        V: View,
  73        F: FnOnce(&mut ViewContext<V>) -> V,
  74    {
  75        let titlebar_height = platform_window.titlebar_height();
  76        let appearance = platform_window.appearance();
  77        let mut window = Self {
  78            layout_engine: Taffy::new(),
  79            root_view: None,
  80            focused_view_id: None,
  81            parents: Default::default(),
  82            is_active: false,
  83            invalidation: None,
  84            is_fullscreen: false,
  85            platform_window,
  86            rendered_views: Default::default(),
  87            cursor_regions: Default::default(),
  88            mouse_regions: Default::default(),
  89            text_layout_cache: TextLayoutCache::new(cx.font_system.clone()),
  90            last_mouse_moved_event: None,
  91            hovered_region_ids: Default::default(),
  92            clicked_region_ids: Default::default(),
  93            clicked_region: None,
  94            mouse_position: vec2f(0., 0.),
  95            titlebar_height,
  96            appearance,
  97        };
  98
  99        let mut window_context = WindowContext::mutable(cx, &mut window, handle);
 100        let root_view = window_context.add_view(|cx| build_view(cx));
 101        if let Some(invalidation) = window_context.window.invalidation.take() {
 102            window_context.invalidate(invalidation, appearance);
 103        }
 104        window.focused_view_id = Some(root_view.id());
 105        window.root_view = Some(root_view.into_any());
 106        window
 107    }
 108
 109    pub fn root_view(&self) -> &AnyViewHandle {
 110        &self
 111            .root_view
 112            .as_ref()
 113            .expect("root_view called during window construction")
 114    }
 115}
 116
 117pub struct WindowContext<'a> {
 118    pub(crate) app_context: Reference<'a, AppContext>,
 119    pub(crate) window: Reference<'a, Window>,
 120    pub(crate) window_handle: AnyWindowHandle,
 121    pub(crate) removed: bool,
 122}
 123
 124impl Deref for WindowContext<'_> {
 125    type Target = AppContext;
 126
 127    fn deref(&self) -> &Self::Target {
 128        &self.app_context
 129    }
 130}
 131
 132impl DerefMut for WindowContext<'_> {
 133    fn deref_mut(&mut self) -> &mut Self::Target {
 134        &mut self.app_context
 135    }
 136}
 137
 138impl BorrowAppContext for WindowContext<'_> {
 139    fn read_with<T, F: FnOnce(&AppContext) -> T>(&self, f: F) -> T {
 140        self.app_context.read_with(f)
 141    }
 142
 143    fn update<T, F: FnOnce(&mut AppContext) -> T>(&mut self, f: F) -> T {
 144        self.app_context.update(f)
 145    }
 146}
 147
 148impl BorrowWindowContext for WindowContext<'_> {
 149    type Result<T> = T;
 150
 151    fn read_window<T, F: FnOnce(&WindowContext) -> T>(&self, handle: AnyWindowHandle, f: F) -> T {
 152        if self.window_handle == handle {
 153            f(self)
 154        } else {
 155            panic!("read_with called with id of window that does not belong to this context")
 156        }
 157    }
 158
 159    fn read_window_optional<T, F>(&self, window: AnyWindowHandle, f: F) -> Option<T>
 160    where
 161        F: FnOnce(&WindowContext) -> Option<T>,
 162    {
 163        BorrowWindowContext::read_window(self, window, f)
 164    }
 165
 166    fn update_window<T, F: FnOnce(&mut WindowContext) -> T>(
 167        &mut self,
 168        handle: AnyWindowHandle,
 169        f: F,
 170    ) -> T {
 171        if self.window_handle == handle {
 172            f(self)
 173        } else {
 174            panic!("update called with id of window that does not belong to this context")
 175        }
 176    }
 177
 178    fn update_window_optional<T, F>(&mut self, handle: AnyWindowHandle, f: F) -> Option<T>
 179    where
 180        F: FnOnce(&mut WindowContext) -> Option<T>,
 181    {
 182        BorrowWindowContext::update_window(self, handle, f)
 183    }
 184}
 185
 186impl<'a> WindowContext<'a> {
 187    pub fn mutable(
 188        app_context: &'a mut AppContext,
 189        window: &'a mut Window,
 190        handle: AnyWindowHandle,
 191    ) -> Self {
 192        Self {
 193            app_context: Reference::Mutable(app_context),
 194            window: Reference::Mutable(window),
 195            window_handle: handle,
 196            removed: false,
 197        }
 198    }
 199
 200    pub fn immutable(
 201        app_context: &'a AppContext,
 202        window: &'a Window,
 203        handle: AnyWindowHandle,
 204    ) -> Self {
 205        Self {
 206            app_context: Reference::Immutable(app_context),
 207            window: Reference::Immutable(window),
 208            window_handle: handle,
 209            removed: false,
 210        }
 211    }
 212
 213    pub fn layout_engine(&mut self) -> &mut Taffy {
 214        &mut self.window.layout_engine
 215    }
 216
 217    pub fn remove_window(&mut self) {
 218        self.removed = true;
 219    }
 220
 221    pub fn window(&self) -> AnyWindowHandle {
 222        self.window_handle
 223    }
 224
 225    pub fn app_context(&mut self) -> &mut AppContext {
 226        &mut self.app_context
 227    }
 228
 229    pub fn root_view(&self) -> &AnyViewHandle {
 230        self.window.root_view()
 231    }
 232
 233    pub fn window_size(&self) -> Vector2F {
 234        self.window.platform_window.content_size()
 235    }
 236
 237    pub fn text_layout_cache(&self) -> &TextLayoutCache {
 238        &self.window.text_layout_cache
 239    }
 240
 241    pub(crate) fn update_any_view<F, T>(&mut self, view_id: usize, f: F) -> Option<T>
 242    where
 243        F: FnOnce(&mut dyn AnyView, &mut Self) -> T,
 244    {
 245        let handle = self.window_handle;
 246        let mut view = self.views.remove(&(handle, view_id))?;
 247        let result = f(view.as_mut(), self);
 248        self.views.insert((handle, view_id), view);
 249        Some(result)
 250    }
 251
 252    pub(crate) fn update_view<V: 'static, S>(
 253        &mut self,
 254        handle: &ViewHandle<V>,
 255        update: &mut dyn FnMut(&mut V, &mut ViewContext<V>) -> S,
 256    ) -> S {
 257        self.update_any_view(handle.view_id, |view, cx| {
 258            let mut cx = ViewContext::mutable(cx, handle.view_id);
 259            update(
 260                view.as_any_mut()
 261                    .downcast_mut()
 262                    .expect("downcast is type safe"),
 263                &mut cx,
 264            )
 265        })
 266        .expect("view is already on the stack")
 267    }
 268
 269    pub fn defer(&mut self, callback: impl 'static + FnOnce(&mut WindowContext)) {
 270        let handle = self.window_handle;
 271        self.app_context.defer(move |cx| {
 272            cx.update_window(handle, |cx| callback(cx));
 273        })
 274    }
 275
 276    pub fn update_global<T, F, U>(&mut self, update: F) -> U
 277    where
 278        T: 'static,
 279        F: FnOnce(&mut T, &mut Self) -> U,
 280    {
 281        AppContext::update_global_internal(self, |global, cx| update(global, cx))
 282    }
 283
 284    pub fn update_default_global<T, F, U>(&mut self, update: F) -> U
 285    where
 286        T: 'static + Default,
 287        F: FnOnce(&mut T, &mut Self) -> U,
 288    {
 289        AppContext::update_default_global_internal(self, |global, cx| update(global, cx))
 290    }
 291
 292    pub fn subscribe<E, H, F>(&mut self, handle: &H, mut callback: F) -> Subscription
 293    where
 294        E: Entity,
 295        E::Event: 'static,
 296        H: Handle<E>,
 297        F: 'static + FnMut(H, &E::Event, &mut WindowContext),
 298    {
 299        self.subscribe_internal(handle, move |emitter, event, cx| {
 300            callback(emitter, event, cx);
 301            true
 302        })
 303    }
 304
 305    pub fn subscribe_internal<E, H, F>(&mut self, handle: &H, mut callback: F) -> Subscription
 306    where
 307        E: Entity,
 308        E::Event: 'static,
 309        H: Handle<E>,
 310        F: 'static + FnMut(H, &E::Event, &mut WindowContext) -> bool,
 311    {
 312        let window_handle = self.window_handle;
 313        self.app_context
 314            .subscribe_internal(handle, move |emitter, event, cx| {
 315                cx.update_window(window_handle, |cx| callback(emitter, event, cx))
 316                    .unwrap_or(false)
 317            })
 318    }
 319
 320    pub(crate) fn observe_window_activation<F>(&mut self, callback: F) -> Subscription
 321    where
 322        F: 'static + FnMut(bool, &mut WindowContext) -> bool,
 323    {
 324        let handle = self.window_handle;
 325        let subscription_id = post_inc(&mut self.next_subscription_id);
 326        self.pending_effects
 327            .push_back(Effect::WindowActivationObservation {
 328                window: handle,
 329                subscription_id,
 330                callback: Box::new(callback),
 331            });
 332        Subscription::WindowActivationObservation(
 333            self.window_activation_observations
 334                .subscribe(handle, subscription_id),
 335        )
 336    }
 337
 338    pub(crate) fn observe_fullscreen<F>(&mut self, callback: F) -> Subscription
 339    where
 340        F: 'static + FnMut(bool, &mut WindowContext) -> bool,
 341    {
 342        let window = self.window_handle;
 343        let subscription_id = post_inc(&mut self.next_subscription_id);
 344        self.pending_effects
 345            .push_back(Effect::WindowFullscreenObservation {
 346                window,
 347                subscription_id,
 348                callback: Box::new(callback),
 349            });
 350        Subscription::WindowActivationObservation(
 351            self.window_activation_observations
 352                .subscribe(window, subscription_id),
 353        )
 354    }
 355
 356    pub(crate) fn observe_window_bounds<F>(&mut self, callback: F) -> Subscription
 357    where
 358        F: 'static + FnMut(WindowBounds, Uuid, &mut WindowContext) -> bool,
 359    {
 360        let window = self.window_handle;
 361        let subscription_id = post_inc(&mut self.next_subscription_id);
 362        self.pending_effects
 363            .push_back(Effect::WindowBoundsObservation {
 364                window,
 365                subscription_id,
 366                callback: Box::new(callback),
 367            });
 368        Subscription::WindowBoundsObservation(
 369            self.window_bounds_observations
 370                .subscribe(window, subscription_id),
 371        )
 372    }
 373
 374    pub fn observe_keystrokes<F>(&mut self, callback: F) -> Subscription
 375    where
 376        F: 'static
 377            + FnMut(&Keystroke, &MatchResult, Option<&Box<dyn Action>>, &mut WindowContext) -> bool,
 378    {
 379        let window = self.window_handle;
 380        let subscription_id = post_inc(&mut self.next_subscription_id);
 381        self.keystroke_observations
 382            .add_callback(window, subscription_id, Box::new(callback));
 383        Subscription::KeystrokeObservation(
 384            self.keystroke_observations
 385                .subscribe(window, subscription_id),
 386        )
 387    }
 388
 389    pub(crate) fn available_actions(
 390        &self,
 391        view_id: usize,
 392    ) -> Vec<(&'static str, Box<dyn Action>, SmallVec<[Binding; 1]>)> {
 393        let handle = self.window_handle;
 394        let mut contexts = Vec::new();
 395        let mut handler_depths_by_action_id = HashMap::<TypeId, usize>::default();
 396        for (depth, view_id) in self.ancestors(view_id).enumerate() {
 397            if let Some(view_metadata) = self.views_metadata.get(&(handle, view_id)) {
 398                contexts.push(view_metadata.keymap_context.clone());
 399                if let Some(actions) = self.actions.get(&view_metadata.type_id) {
 400                    handler_depths_by_action_id
 401                        .extend(actions.keys().copied().map(|action_id| (action_id, depth)));
 402                }
 403            } else {
 404                log::error!(
 405                    "view {} not found when computing available actions",
 406                    view_id
 407                );
 408            }
 409        }
 410
 411        handler_depths_by_action_id.extend(
 412            self.global_actions
 413                .keys()
 414                .copied()
 415                .map(|action_id| (action_id, contexts.len())),
 416        );
 417
 418        self.action_deserializers
 419            .iter()
 420            .filter_map(move |(name, (action_id, deserialize))| {
 421                if let Some(action_depth) = handler_depths_by_action_id.get(action_id).copied() {
 422                    let action = deserialize(serde_json::Value::Object(Default::default())).ok()?;
 423                    let bindings = self
 424                        .keystroke_matcher
 425                        .bindings_for_action(*action_id)
 426                        .filter(|b| {
 427                            action.eq(b.action())
 428                                && (0..=action_depth)
 429                                    .any(|depth| b.match_context(&contexts[depth..]))
 430                        })
 431                        .cloned()
 432                        .collect();
 433                    Some((*name, action, bindings))
 434                } else {
 435                    None
 436                }
 437            })
 438            .collect()
 439    }
 440
 441    pub(crate) fn dispatch_keystroke(&mut self, keystroke: &Keystroke) -> bool {
 442        let handle = self.window_handle;
 443        if let Some(focused_view_id) = self.focused_view_id() {
 444            let dispatch_path = self
 445                .ancestors(focused_view_id)
 446                .filter_map(|view_id| {
 447                    self.views_metadata
 448                        .get(&(handle, view_id))
 449                        .map(|view| (view_id, view.keymap_context.clone()))
 450                })
 451                .collect();
 452
 453            let match_result = self
 454                .keystroke_matcher
 455                .push_keystroke(keystroke.clone(), dispatch_path);
 456            let mut handled_by = None;
 457
 458            let keystroke_handled = match &match_result {
 459                MatchResult::None => false,
 460                MatchResult::Pending => true,
 461                MatchResult::Matches(matches) => {
 462                    for (view_id, action) in matches {
 463                        if self.dispatch_action(Some(*view_id), action.as_ref()) {
 464                            self.keystroke_matcher.clear_pending();
 465                            handled_by = Some(action.boxed_clone());
 466                            break;
 467                        }
 468                    }
 469                    handled_by.is_some()
 470                }
 471            };
 472
 473            self.keystroke(handle, keystroke.clone(), handled_by, match_result.clone());
 474            keystroke_handled
 475        } else {
 476            self.keystroke(handle, keystroke.clone(), None, MatchResult::None);
 477            false
 478        }
 479    }
 480
 481    pub(crate) fn dispatch_event(&mut self, event: Event, event_reused: bool) -> bool {
 482        let mut mouse_events = SmallVec::<[_; 2]>::new();
 483        let mut notified_views: HashSet<usize> = Default::default();
 484        let handle = self.window_handle;
 485
 486        // 1. Handle platform event. Keyboard events get dispatched immediately, while mouse events
 487        //    get mapped into the mouse-specific MouseEvent type.
 488        //  -> These are usually small: [Mouse Down] or [Mouse up, Click] or [Mouse Moved, Mouse Dragged?]
 489        //  -> Also updates mouse-related state
 490        match &event {
 491            Event::KeyDown(e) => return self.dispatch_key_down(e),
 492
 493            Event::KeyUp(e) => return self.dispatch_key_up(e),
 494
 495            Event::ModifiersChanged(e) => return self.dispatch_modifiers_changed(e),
 496
 497            Event::MouseDown(e) => {
 498                // Click events are weird because they can be fired after a drag event.
 499                // MDN says that browsers handle this by starting from 'the most
 500                // specific ancestor element that contained both [positions]'
 501                // So we need to store the overlapping regions on mouse down.
 502
 503                // If there is already region being clicked, don't replace it.
 504                if self.window.clicked_region.is_none() {
 505                    self.window.clicked_region_ids = self
 506                        .window
 507                        .mouse_regions
 508                        .iter()
 509                        .filter_map(|(region, _)| {
 510                            if region.bounds.contains_point(e.position) {
 511                                Some(region.id())
 512                            } else {
 513                                None
 514                            }
 515                        })
 516                        .collect();
 517
 518                    let mut highest_z_index = 0;
 519                    let mut clicked_region_id = None;
 520                    for (region, z_index) in self.window.mouse_regions.iter() {
 521                        if region.bounds.contains_point(e.position) && *z_index >= highest_z_index {
 522                            highest_z_index = *z_index;
 523                            clicked_region_id = Some(region.id());
 524                        }
 525                    }
 526
 527                    self.window.clicked_region =
 528                        clicked_region_id.map(|region_id| (region_id, e.button));
 529                }
 530
 531                mouse_events.push(MouseEvent::Down(MouseDown {
 532                    region: Default::default(),
 533                    platform_event: e.clone(),
 534                }));
 535                mouse_events.push(MouseEvent::DownOut(MouseDownOut {
 536                    region: Default::default(),
 537                    platform_event: e.clone(),
 538                }));
 539            }
 540
 541            Event::MouseUp(e) => {
 542                // NOTE: The order of event pushes is important! MouseUp events MUST be fired
 543                // before click events, and so the MouseUp events need to be pushed before
 544                // MouseClick events.
 545
 546                // Synthesize one last drag event to end the drag
 547                mouse_events.push(MouseEvent::Drag(MouseDrag {
 548                    region: Default::default(),
 549                    prev_mouse_position: self.window.mouse_position,
 550                    platform_event: MouseMovedEvent {
 551                        position: e.position,
 552                        pressed_button: Some(e.button),
 553                        modifiers: e.modifiers,
 554                    },
 555                    end: true,
 556                }));
 557                mouse_events.push(MouseEvent::Up(MouseUp {
 558                    region: Default::default(),
 559                    platform_event: e.clone(),
 560                }));
 561                mouse_events.push(MouseEvent::UpOut(MouseUpOut {
 562                    region: Default::default(),
 563                    platform_event: e.clone(),
 564                }));
 565                mouse_events.push(MouseEvent::Click(MouseClick {
 566                    region: Default::default(),
 567                    platform_event: e.clone(),
 568                }));
 569                mouse_events.push(MouseEvent::ClickOut(MouseClickOut {
 570                    region: Default::default(),
 571                    platform_event: e.clone(),
 572                }));
 573            }
 574
 575            Event::MouseMoved(
 576                e @ MouseMovedEvent {
 577                    position,
 578                    pressed_button,
 579                    ..
 580                },
 581            ) => {
 582                let mut style_to_assign = CursorStyle::Arrow;
 583                for region in self.window.cursor_regions.iter().rev() {
 584                    if region.bounds.contains_point(*position) {
 585                        style_to_assign = region.style;
 586                        break;
 587                    }
 588                }
 589
 590                if self
 591                    .window
 592                    .platform_window
 593                    .is_topmost_for_position(*position)
 594                {
 595                    self.platform().set_cursor_style(style_to_assign);
 596                }
 597
 598                if !event_reused {
 599                    if pressed_button.is_some() {
 600                        mouse_events.push(MouseEvent::Drag(MouseDrag {
 601                            region: Default::default(),
 602                            prev_mouse_position: self.window.mouse_position,
 603                            platform_event: e.clone(),
 604                            end: false,
 605                        }));
 606                    } else if let Some((_, clicked_button)) = self.window.clicked_region {
 607                        mouse_events.push(MouseEvent::Drag(MouseDrag {
 608                            region: Default::default(),
 609                            prev_mouse_position: self.window.mouse_position,
 610                            platform_event: e.clone(),
 611                            end: true,
 612                        }));
 613
 614                        // Mouse up event happened outside the current window. Simulate mouse up button event
 615                        let button_event = e.to_button_event(clicked_button);
 616                        mouse_events.push(MouseEvent::Up(MouseUp {
 617                            region: Default::default(),
 618                            platform_event: button_event.clone(),
 619                        }));
 620                        mouse_events.push(MouseEvent::UpOut(MouseUpOut {
 621                            region: Default::default(),
 622                            platform_event: button_event.clone(),
 623                        }));
 624                        mouse_events.push(MouseEvent::Click(MouseClick {
 625                            region: Default::default(),
 626                            platform_event: button_event.clone(),
 627                        }));
 628                    }
 629
 630                    mouse_events.push(MouseEvent::Move(MouseMove {
 631                        region: Default::default(),
 632                        platform_event: e.clone(),
 633                    }));
 634                }
 635
 636                mouse_events.push(MouseEvent::Hover(MouseHover {
 637                    region: Default::default(),
 638                    platform_event: e.clone(),
 639                    started: false,
 640                }));
 641                mouse_events.push(MouseEvent::MoveOut(MouseMoveOut {
 642                    region: Default::default(),
 643                }));
 644
 645                self.window.last_mouse_moved_event = Some(event.clone());
 646            }
 647
 648            Event::MouseExited(event) => {
 649                // When the platform sends a MouseExited event, synthesize
 650                // a MouseMoved event whose position is outside the window's
 651                // bounds so that hover and cursor state can be updated.
 652                return self.dispatch_event(
 653                    Event::MouseMoved(MouseMovedEvent {
 654                        position: event.position,
 655                        pressed_button: event.pressed_button,
 656                        modifiers: event.modifiers,
 657                    }),
 658                    event_reused,
 659                );
 660            }
 661
 662            Event::ScrollWheel(e) => mouse_events.push(MouseEvent::ScrollWheel(MouseScrollWheel {
 663                region: Default::default(),
 664                platform_event: e.clone(),
 665            })),
 666        }
 667
 668        if let Some(position) = event.position() {
 669            self.window.mouse_position = position;
 670        }
 671
 672        // 2. Dispatch mouse events on regions
 673        let mut any_event_handled = false;
 674        for mut mouse_event in mouse_events {
 675            let mut valid_regions = Vec::new();
 676
 677            // GPUI elements are arranged by z_index but sibling elements can register overlapping
 678            // mouse regions. As such, hover events are only fired on overlapping elements which
 679            // are at the same z-index as the topmost element which overlaps with the mouse.
 680            match &mouse_event {
 681                MouseEvent::Hover(_) => {
 682                    let mut highest_z_index = None;
 683                    let mouse_position = self.window.mouse_position.clone();
 684                    let window = &mut *self.window;
 685                    for (region, z_index) in window.mouse_regions.iter().rev() {
 686                        // Allow mouse regions to appear transparent to hovers
 687                        if !region.hoverable {
 688                            continue;
 689                        }
 690
 691                        let contains_mouse = region.bounds.contains_point(mouse_position);
 692
 693                        if contains_mouse && highest_z_index.is_none() {
 694                            highest_z_index = Some(z_index);
 695                        }
 696
 697                        // This unwrap relies on short circuiting boolean expressions
 698                        // The right side of the && is only executed when contains_mouse
 699                        // is true, and we know above that when contains_mouse is true
 700                        // highest_z_index is set.
 701                        if contains_mouse && z_index == highest_z_index.unwrap() {
 702                            //Ensure that hover entrance events aren't sent twice
 703                            if window.hovered_region_ids.insert(region.id()) {
 704                                valid_regions.push(region.clone());
 705                                if region.notify_on_hover {
 706                                    notified_views.insert(region.id().view_id());
 707                                }
 708                            }
 709                        } else {
 710                            // Ensure that hover exit events aren't sent twice
 711                            if window.hovered_region_ids.remove(&region.id()) {
 712                                valid_regions.push(region.clone());
 713                                if region.notify_on_hover {
 714                                    notified_views.insert(region.id().view_id());
 715                                }
 716                            }
 717                        }
 718                    }
 719                }
 720
 721                MouseEvent::Down(_) | MouseEvent::Up(_) => {
 722                    for (region, _) in self.window.mouse_regions.iter().rev() {
 723                        if region.bounds.contains_point(self.window.mouse_position) {
 724                            valid_regions.push(region.clone());
 725                            if region.notify_on_click {
 726                                notified_views.insert(region.id().view_id());
 727                            }
 728                        }
 729                    }
 730                }
 731
 732                MouseEvent::Click(e) => {
 733                    // Only raise click events if the released button is the same as the one stored
 734                    if self
 735                        .window
 736                        .clicked_region
 737                        .map(|(_, clicked_button)| clicked_button == e.button)
 738                        .unwrap_or(false)
 739                    {
 740                        // Clear clicked regions and clicked button
 741                        let clicked_region_ids = std::mem::replace(
 742                            &mut self.window.clicked_region_ids,
 743                            Default::default(),
 744                        );
 745                        self.window.clicked_region = None;
 746
 747                        // Find regions which still overlap with the mouse since the last MouseDown happened
 748                        for (mouse_region, _) in self.window.mouse_regions.iter().rev() {
 749                            if clicked_region_ids.contains(&mouse_region.id()) {
 750                                if mouse_region
 751                                    .bounds
 752                                    .contains_point(self.window.mouse_position)
 753                                {
 754                                    valid_regions.push(mouse_region.clone());
 755                                }
 756                            }
 757                        }
 758                    }
 759                }
 760
 761                MouseEvent::Drag(_) => {
 762                    for (mouse_region, _) in self.window.mouse_regions.iter().rev() {
 763                        if self.window.clicked_region_ids.contains(&mouse_region.id()) {
 764                            valid_regions.push(mouse_region.clone());
 765                        }
 766                    }
 767                }
 768
 769                MouseEvent::MoveOut(_)
 770                | MouseEvent::UpOut(_)
 771                | MouseEvent::DownOut(_)
 772                | MouseEvent::ClickOut(_) => {
 773                    for (mouse_region, _) in self.window.mouse_regions.iter().rev() {
 774                        // NOT contains
 775                        if !mouse_region
 776                            .bounds
 777                            .contains_point(self.window.mouse_position)
 778                        {
 779                            valid_regions.push(mouse_region.clone());
 780                        }
 781                    }
 782                }
 783
 784                _ => {
 785                    for (mouse_region, _) in self.window.mouse_regions.iter().rev() {
 786                        // Contains
 787                        if mouse_region
 788                            .bounds
 789                            .contains_point(self.window.mouse_position)
 790                        {
 791                            valid_regions.push(mouse_region.clone());
 792                        }
 793                    }
 794                }
 795            }
 796
 797            //3. Fire region events
 798            let hovered_region_ids = self.window.hovered_region_ids.clone();
 799            for valid_region in valid_regions.into_iter() {
 800                let mut handled = false;
 801                mouse_event.set_region(valid_region.bounds);
 802                if let MouseEvent::Hover(e) = &mut mouse_event {
 803                    e.started = hovered_region_ids.contains(&valid_region.id())
 804                }
 805                // Handle Down events if the MouseRegion has a Click or Drag handler. This makes the api more intuitive as you would
 806                // not expect a MouseRegion to be transparent to Down events if it also has a Click handler.
 807                // This behavior can be overridden by adding a Down handler
 808                if let MouseEvent::Down(e) = &mouse_event {
 809                    let has_click = valid_region
 810                        .handlers
 811                        .contains(MouseEvent::click_disc(), Some(e.button));
 812                    let has_drag = valid_region
 813                        .handlers
 814                        .contains(MouseEvent::drag_disc(), Some(e.button));
 815                    let has_down = valid_region
 816                        .handlers
 817                        .contains(MouseEvent::down_disc(), Some(e.button));
 818                    if !has_down && (has_click || has_drag) {
 819                        handled = true;
 820                    }
 821                }
 822
 823                // `event_consumed` should only be true if there are any handlers for this event.
 824                let mut event_consumed = handled;
 825                if let Some(callbacks) = valid_region.handlers.get(&mouse_event.handler_key()) {
 826                    for callback in callbacks {
 827                        handled = true;
 828                        let view_id = valid_region.id().view_id();
 829                        self.update_any_view(view_id, |view, cx| {
 830                            handled = callback(mouse_event.clone(), view.as_any_mut(), cx, view_id);
 831                        });
 832                        event_consumed |= handled;
 833                        any_event_handled |= handled;
 834                    }
 835                }
 836
 837                any_event_handled |= handled;
 838
 839                // For bubbling events, if the event was handled, don't continue dispatching.
 840                // This only makes sense for local events which return false from is_capturable.
 841                if event_consumed && mouse_event.is_capturable() {
 842                    break;
 843                }
 844            }
 845        }
 846
 847        for view_id in notified_views {
 848            self.notify_view(handle, view_id);
 849        }
 850
 851        any_event_handled
 852    }
 853
 854    pub(crate) fn dispatch_key_down(&mut self, event: &KeyDownEvent) -> bool {
 855        let handle = self.window_handle;
 856        if let Some(focused_view_id) = self.window.focused_view_id {
 857            for view_id in self.ancestors(focused_view_id).collect::<Vec<_>>() {
 858                if let Some(mut view) = self.views.remove(&(handle, view_id)) {
 859                    let handled = view.key_down(event, self, view_id);
 860                    self.views.insert((handle, view_id), view);
 861                    if handled {
 862                        return true;
 863                    }
 864                } else {
 865                    log::error!("view {} does not exist", view_id)
 866                }
 867            }
 868        }
 869
 870        false
 871    }
 872
 873    pub(crate) fn dispatch_key_up(&mut self, event: &KeyUpEvent) -> bool {
 874        let handle = self.window_handle;
 875        if let Some(focused_view_id) = self.window.focused_view_id {
 876            for view_id in self.ancestors(focused_view_id).collect::<Vec<_>>() {
 877                if let Some(mut view) = self.views.remove(&(handle, view_id)) {
 878                    let handled = view.key_up(event, self, view_id);
 879                    self.views.insert((handle, view_id), view);
 880                    if handled {
 881                        return true;
 882                    }
 883                } else {
 884                    log::error!("view {} does not exist", view_id)
 885                }
 886            }
 887        }
 888
 889        false
 890    }
 891
 892    pub(crate) fn dispatch_modifiers_changed(&mut self, event: &ModifiersChangedEvent) -> bool {
 893        let handle = self.window_handle;
 894        if let Some(focused_view_id) = self.window.focused_view_id {
 895            for view_id in self.ancestors(focused_view_id).collect::<Vec<_>>() {
 896                if let Some(mut view) = self.views.remove(&(handle, view_id)) {
 897                    let handled = view.modifiers_changed(event, self, view_id);
 898                    self.views.insert((handle, view_id), view);
 899                    if handled {
 900                        return true;
 901                    }
 902                } else {
 903                    log::error!("view {} does not exist", view_id)
 904                }
 905            }
 906        }
 907
 908        false
 909    }
 910
 911    pub fn invalidate(&mut self, mut invalidation: WindowInvalidation, appearance: Appearance) {
 912        self.start_frame();
 913        self.window.appearance = appearance;
 914        for view_id in &invalidation.removed {
 915            invalidation.updated.remove(view_id);
 916            self.window.rendered_views.remove(view_id);
 917        }
 918        for view_id in &invalidation.updated {
 919            let titlebar_height = self.window.titlebar_height;
 920            let element = self
 921                .render_view(RenderParams {
 922                    view_id: *view_id,
 923                    titlebar_height,
 924                    refreshing: false,
 925                    appearance,
 926                })
 927                .unwrap();
 928            self.window.rendered_views.insert(*view_id, element);
 929        }
 930    }
 931
 932    pub fn render_view(&mut self, params: RenderParams) -> Result<Box<dyn AnyRootElement>> {
 933        let handle = self.window_handle;
 934        let view_id = params.view_id;
 935        let mut view = self
 936            .views
 937            .remove(&(handle, view_id))
 938            .ok_or_else(|| anyhow!("view not found"))?;
 939        let element = view.render(self, view_id);
 940        self.views.insert((handle, view_id), view);
 941        Ok(element)
 942    }
 943
 944    pub fn layout(&mut self, refreshing: bool) -> Result<HashMap<usize, usize>> {
 945        let window_size = self.window.platform_window.content_size();
 946        let root_view_id = self.window.root_view().id();
 947
 948        let mut rendered_root = self.window.rendered_views.remove(&root_view_id).unwrap();
 949
 950        let mut new_parents = HashMap::default();
 951        let mut views_to_notify_if_ancestors_change = HashMap::default();
 952        rendered_root.layout(
 953            SizeConstraint::new(window_size, window_size),
 954            &mut new_parents,
 955            &mut views_to_notify_if_ancestors_change,
 956            refreshing,
 957            self,
 958        )?;
 959
 960        for (view_id, view_ids_to_notify) in views_to_notify_if_ancestors_change {
 961            let mut current_view_id = view_id;
 962            loop {
 963                let old_parent_id = self.window.parents.get(&current_view_id);
 964                let new_parent_id = new_parents.get(&current_view_id);
 965                if old_parent_id.is_none() && new_parent_id.is_none() {
 966                    break;
 967                } else if old_parent_id == new_parent_id {
 968                    current_view_id = *old_parent_id.unwrap();
 969                } else {
 970                    let handle = self.window_handle;
 971                    for view_id_to_notify in view_ids_to_notify {
 972                        self.notify_view(handle, view_id_to_notify);
 973                    }
 974                    break;
 975                }
 976            }
 977        }
 978
 979        let old_parents = mem::replace(&mut self.window.parents, new_parents);
 980        self.window
 981            .rendered_views
 982            .insert(root_view_id, rendered_root);
 983        Ok(old_parents)
 984    }
 985
 986    pub fn paint(&mut self) -> Result<Scene> {
 987        let window_size = self.window.platform_window.content_size();
 988        let scale_factor = self.window.platform_window.scale_factor();
 989
 990        let root_view_id = self.window.root_view().id();
 991        let mut rendered_root = self.window.rendered_views.remove(&root_view_id).unwrap();
 992
 993        let mut scene_builder = SceneBuilder::new(scale_factor);
 994        rendered_root.paint(
 995            &mut scene_builder,
 996            Vector2F::zero(),
 997            RectF::from_points(Vector2F::zero(), window_size),
 998            self,
 999        )?;
1000        self.window
1001            .rendered_views
1002            .insert(root_view_id, rendered_root);
1003
1004        self.window.text_layout_cache.finish_frame();
1005        let scene = scene_builder.build();
1006        self.window.cursor_regions = scene.cursor_regions();
1007        self.window.mouse_regions = scene.mouse_regions();
1008
1009        if self.window_is_active() {
1010            if let Some(event) = self.window.last_mouse_moved_event.clone() {
1011                self.dispatch_event(event, true);
1012            }
1013        }
1014
1015        Ok(scene)
1016    }
1017
1018    pub fn root_element(&self) -> &Box<dyn AnyRootElement> {
1019        let view_id = self.window.root_view().id();
1020        self.window.rendered_views.get(&view_id).unwrap()
1021    }
1022
1023    pub fn rect_for_text_range(&self, range_utf16: Range<usize>) -> Option<RectF> {
1024        let focused_view_id = self.window.focused_view_id?;
1025        self.window
1026            .rendered_views
1027            .get(&focused_view_id)?
1028            .rect_for_text_range(range_utf16, self)
1029            .log_err()
1030            .flatten()
1031    }
1032
1033    pub fn set_window_title(&mut self, title: &str) {
1034        self.window.platform_window.set_title(title);
1035    }
1036
1037    pub fn set_window_edited(&mut self, edited: bool) {
1038        self.window.platform_window.set_edited(edited);
1039    }
1040
1041    pub fn is_topmost_window_for_position(&self, position: Vector2F) -> bool {
1042        self.window
1043            .platform_window
1044            .is_topmost_for_position(position)
1045    }
1046
1047    pub fn activate_window(&self) {
1048        self.window.platform_window.activate();
1049    }
1050
1051    pub fn window_is_active(&self) -> bool {
1052        self.window.is_active
1053    }
1054
1055    pub fn window_is_fullscreen(&self) -> bool {
1056        self.window.is_fullscreen
1057    }
1058
1059    pub(crate) fn dispatch_action(&mut self, view_id: Option<usize>, action: &dyn Action) -> bool {
1060        if let Some(view_id) = view_id {
1061            self.halt_action_dispatch = false;
1062            self.visit_dispatch_path(view_id, |view_id, capture_phase, cx| {
1063                cx.update_any_view(view_id, |view, cx| {
1064                    let type_id = view.as_any().type_id();
1065                    if let Some((name, mut handlers)) = cx
1066                        .actions_mut(capture_phase)
1067                        .get_mut(&type_id)
1068                        .and_then(|h| h.remove_entry(&action.id()))
1069                    {
1070                        for handler in handlers.iter_mut().rev() {
1071                            cx.halt_action_dispatch = true;
1072                            handler(view, action, cx, view_id);
1073                            if cx.halt_action_dispatch {
1074                                break;
1075                            }
1076                        }
1077                        cx.actions_mut(capture_phase)
1078                            .get_mut(&type_id)
1079                            .unwrap()
1080                            .insert(name, handlers);
1081                    }
1082                });
1083
1084                !cx.halt_action_dispatch
1085            });
1086        }
1087
1088        if !self.halt_action_dispatch {
1089            self.halt_action_dispatch = self.dispatch_global_action_any(action);
1090        }
1091
1092        self.pending_effects
1093            .push_back(Effect::ActionDispatchNotification {
1094                action_id: action.id(),
1095            });
1096        self.halt_action_dispatch
1097    }
1098
1099    /// Returns an iterator over all of the view ids from the passed view up to the root of the window
1100    /// Includes the passed view itself
1101    pub(crate) fn ancestors(&self, mut view_id: usize) -> impl Iterator<Item = usize> + '_ {
1102        std::iter::once(view_id)
1103            .into_iter()
1104            .chain(std::iter::from_fn(move || {
1105                if let Some(parent_id) = self.window.parents.get(&view_id) {
1106                    view_id = *parent_id;
1107                    Some(view_id)
1108                } else {
1109                    None
1110                }
1111            }))
1112    }
1113
1114    // Traverses the parent tree. Walks down the tree toward the passed
1115    // view calling visit with true. Then walks back up the tree calling visit with false.
1116    // If `visit` returns false this function will immediately return.
1117    fn visit_dispatch_path(
1118        &mut self,
1119        view_id: usize,
1120        mut visit: impl FnMut(usize, bool, &mut WindowContext) -> bool,
1121    ) {
1122        // List of view ids from the leaf to the root of the window
1123        let path = self.ancestors(view_id).collect::<Vec<_>>();
1124
1125        // Walk down from the root to the leaf calling visit with capture_phase = true
1126        for view_id in path.iter().rev() {
1127            if !visit(*view_id, true, self) {
1128                return;
1129            }
1130        }
1131
1132        // Walk up from the leaf to the root calling visit with capture_phase = false
1133        for view_id in path.iter() {
1134            if !visit(*view_id, false, self) {
1135                return;
1136            }
1137        }
1138    }
1139
1140    pub fn focused_view_id(&self) -> Option<usize> {
1141        self.window.focused_view_id
1142    }
1143
1144    pub fn focus(&mut self, view_id: Option<usize>) {
1145        self.app_context.focus(self.window_handle, view_id);
1146    }
1147
1148    pub fn window_bounds(&self) -> WindowBounds {
1149        self.window.platform_window.bounds()
1150    }
1151
1152    pub fn window_appearance(&self) -> Appearance {
1153        self.window.appearance
1154    }
1155
1156    pub fn window_display_uuid(&self) -> Option<Uuid> {
1157        self.window.platform_window.screen().display_uuid()
1158    }
1159
1160    pub fn show_character_palette(&self) {
1161        self.window.platform_window.show_character_palette();
1162    }
1163
1164    pub fn minimize_window(&self) {
1165        self.window.platform_window.minimize();
1166    }
1167
1168    pub fn zoom_window(&self) {
1169        self.window.platform_window.zoom();
1170    }
1171
1172    pub fn toggle_full_screen(&self) {
1173        self.window.platform_window.toggle_full_screen();
1174    }
1175
1176    pub fn prompt(
1177        &self,
1178        level: PromptLevel,
1179        msg: &str,
1180        answers: &[&str],
1181    ) -> oneshot::Receiver<usize> {
1182        self.window.platform_window.prompt(level, msg, answers)
1183    }
1184
1185    pub fn add_view<T, F>(&mut self, build_view: F) -> ViewHandle<T>
1186    where
1187        T: View,
1188        F: FnOnce(&mut ViewContext<T>) -> T,
1189    {
1190        self.add_option_view(|cx| Some(build_view(cx))).unwrap()
1191    }
1192
1193    pub fn add_option_view<T, F>(&mut self, build_view: F) -> Option<ViewHandle<T>>
1194    where
1195        T: View,
1196        F: FnOnce(&mut ViewContext<T>) -> Option<T>,
1197    {
1198        let handle = self.window_handle;
1199        let view_id = post_inc(&mut self.next_id);
1200        let mut cx = ViewContext::mutable(self, view_id);
1201        let handle = if let Some(view) = build_view(&mut cx) {
1202            let mut keymap_context = KeymapContext::default();
1203            view.update_keymap_context(&mut keymap_context, cx.app_context());
1204            self.views_metadata.insert(
1205                (handle, view_id),
1206                ViewMetadata {
1207                    type_id: TypeId::of::<T>(),
1208                    keymap_context,
1209                },
1210            );
1211            self.views.insert((handle, view_id), Box::new(view));
1212            self.window
1213                .invalidation
1214                .get_or_insert_with(Default::default)
1215                .updated
1216                .insert(view_id);
1217            Some(ViewHandle::new(handle, view_id, &self.ref_counts))
1218        } else {
1219            None
1220        };
1221        handle
1222    }
1223}
1224
1225pub struct RenderParams {
1226    pub view_id: usize,
1227    pub titlebar_height: f32,
1228    pub refreshing: bool,
1229    pub appearance: Appearance,
1230}
1231
1232#[derive(Clone, Copy, Debug, Default, Eq, PartialEq)]
1233pub enum Axis {
1234    #[default]
1235    Horizontal,
1236    Vertical,
1237}
1238
1239impl Axis {
1240    pub fn invert(self) -> Self {
1241        match self {
1242            Self::Horizontal => Self::Vertical,
1243            Self::Vertical => Self::Horizontal,
1244        }
1245    }
1246
1247    pub fn component(&self, point: Vector2F) -> f32 {
1248        match self {
1249            Self::Horizontal => point.x(),
1250            Self::Vertical => point.y(),
1251        }
1252    }
1253}
1254
1255impl ToJson for Axis {
1256    fn to_json(&self) -> serde_json::Value {
1257        match self {
1258            Axis::Horizontal => json!("horizontal"),
1259            Axis::Vertical => json!("vertical"),
1260        }
1261    }
1262}
1263
1264impl StaticColumnCount for Axis {}
1265impl Bind for Axis {
1266    fn bind(&self, statement: &Statement, start_index: i32) -> anyhow::Result<i32> {
1267        match self {
1268            Axis::Horizontal => "Horizontal",
1269            Axis::Vertical => "Vertical",
1270        }
1271        .bind(statement, start_index)
1272    }
1273}
1274
1275impl Column for Axis {
1276    fn column(statement: &mut Statement, start_index: i32) -> anyhow::Result<(Self, i32)> {
1277        String::column(statement, start_index).and_then(|(axis_text, next_index)| {
1278            Ok((
1279                match axis_text.as_str() {
1280                    "Horizontal" => Axis::Horizontal,
1281                    "Vertical" => Axis::Vertical,
1282                    _ => bail!("Stored serialized item kind is incorrect"),
1283                },
1284                next_index,
1285            ))
1286        })
1287    }
1288}
1289
1290pub trait Vector2FExt {
1291    fn along(self, axis: Axis) -> f32;
1292}
1293
1294impl Vector2FExt for Vector2F {
1295    fn along(self, axis: Axis) -> f32 {
1296        match axis {
1297            Axis::Horizontal => self.x(),
1298            Axis::Vertical => self.y(),
1299        }
1300    }
1301}
1302
1303pub trait RectFExt {
1304    fn length_along(self, axis: Axis) -> f32;
1305}
1306
1307impl RectFExt for RectF {
1308    fn length_along(self, axis: Axis) -> f32 {
1309        match axis {
1310            Axis::Horizontal => self.width(),
1311            Axis::Vertical => self.height(),
1312        }
1313    }
1314}
1315
1316#[derive(Copy, Clone, Debug)]
1317pub struct SizeConstraint {
1318    pub min: Vector2F,
1319    pub max: Vector2F,
1320}
1321
1322impl SizeConstraint {
1323    pub fn new(min: Vector2F, max: Vector2F) -> Self {
1324        Self { min, max }
1325    }
1326
1327    pub fn strict(size: Vector2F) -> Self {
1328        Self {
1329            min: size,
1330            max: size,
1331        }
1332    }
1333    pub fn loose(max: Vector2F) -> Self {
1334        Self {
1335            min: Vector2F::zero(),
1336            max,
1337        }
1338    }
1339
1340    pub fn strict_along(axis: Axis, max: f32) -> Self {
1341        match axis {
1342            Axis::Horizontal => Self {
1343                min: vec2f(max, 0.0),
1344                max: vec2f(max, f32::INFINITY),
1345            },
1346            Axis::Vertical => Self {
1347                min: vec2f(0.0, max),
1348                max: vec2f(f32::INFINITY, max),
1349            },
1350        }
1351    }
1352
1353    pub fn max_along(&self, axis: Axis) -> f32 {
1354        match axis {
1355            Axis::Horizontal => self.max.x(),
1356            Axis::Vertical => self.max.y(),
1357        }
1358    }
1359
1360    pub fn min_along(&self, axis: Axis) -> f32 {
1361        match axis {
1362            Axis::Horizontal => self.min.x(),
1363            Axis::Vertical => self.min.y(),
1364        }
1365    }
1366
1367    pub fn constrain(&self, size: Vector2F) -> Vector2F {
1368        vec2f(
1369            size.x().min(self.max.x()).max(self.min.x()),
1370            size.y().min(self.max.y()).max(self.min.y()),
1371        )
1372    }
1373}
1374
1375impl Sub<Vector2F> for SizeConstraint {
1376    type Output = SizeConstraint;
1377
1378    fn sub(self, rhs: Vector2F) -> SizeConstraint {
1379        SizeConstraint {
1380            min: self.min - rhs,
1381            max: self.max - rhs,
1382        }
1383    }
1384}
1385
1386impl Default for SizeConstraint {
1387    fn default() -> Self {
1388        SizeConstraint {
1389            min: Vector2F::zero(),
1390            max: Vector2F::splat(f32::INFINITY),
1391        }
1392    }
1393}
1394
1395impl ToJson for SizeConstraint {
1396    fn to_json(&self) -> serde_json::Value {
1397        json!({
1398            "min": self.min.to_json(),
1399            "max": self.max.to_json(),
1400        })
1401    }
1402}
1403
1404pub struct ChildView {
1405    view_id: usize,
1406    view_name: &'static str,
1407}
1408
1409impl ChildView {
1410    pub fn new(view: &AnyViewHandle, cx: &AppContext) -> Self {
1411        let view_name = cx.view_ui_name(view.window, view.id()).unwrap();
1412        Self {
1413            view_id: view.id(),
1414            view_name,
1415        }
1416    }
1417}
1418
1419impl<V: 'static> Element<V> for ChildView {
1420    type LayoutState = ();
1421    type PaintState = ();
1422
1423    fn layout(
1424        &mut self,
1425        constraint: SizeConstraint,
1426        _: &mut V,
1427        cx: &mut LayoutContext<V>,
1428    ) -> (Vector2F, Self::LayoutState) {
1429        if let Some(mut rendered_view) = cx.window.rendered_views.remove(&self.view_id) {
1430            cx.new_parents.insert(self.view_id, cx.view_id());
1431            let size = rendered_view
1432                .layout(
1433                    constraint,
1434                    cx.new_parents,
1435                    cx.views_to_notify_if_ancestors_change,
1436                    cx.refreshing,
1437                    cx.view_context,
1438                )
1439                .log_err()
1440                .unwrap_or(Vector2F::zero());
1441            cx.window.rendered_views.insert(self.view_id, rendered_view);
1442            (size, ())
1443        } else {
1444            log::error!(
1445                "layout called on a ChildView element whose underlying view was dropped (view_id: {}, name: {:?})",
1446                self.view_id,
1447                self.view_name
1448            );
1449            (Vector2F::zero(), ())
1450        }
1451    }
1452
1453    fn paint(
1454        &mut self,
1455        scene: &mut SceneBuilder,
1456        bounds: RectF,
1457        visible_bounds: RectF,
1458        _: &mut Self::LayoutState,
1459        _: &mut V,
1460        cx: &mut PaintContext<V>,
1461    ) {
1462        if let Some(mut rendered_view) = cx.window.rendered_views.remove(&self.view_id) {
1463            rendered_view
1464                .paint(scene, bounds.origin(), visible_bounds, cx)
1465                .log_err();
1466            cx.window.rendered_views.insert(self.view_id, rendered_view);
1467        } else {
1468            log::error!(
1469                "paint called on a ChildView element whose underlying view was dropped (view_id: {}, name: {:?})",
1470                self.view_id,
1471                self.view_name
1472            );
1473        }
1474    }
1475
1476    fn rect_for_text_range(
1477        &self,
1478        range_utf16: Range<usize>,
1479        _: RectF,
1480        _: RectF,
1481        _: &Self::LayoutState,
1482        _: &Self::PaintState,
1483        _: &V,
1484        cx: &ViewContext<V>,
1485    ) -> Option<RectF> {
1486        if let Some(rendered_view) = cx.window.rendered_views.get(&self.view_id) {
1487            rendered_view
1488                .rect_for_text_range(range_utf16, &cx.window_context)
1489                .log_err()
1490                .flatten()
1491        } else {
1492            log::error!(
1493                "rect_for_text_range called on a ChildView element whose underlying view was dropped (view_id: {}, name: {:?})",
1494                self.view_id,
1495                self.view_name
1496            );
1497            None
1498        }
1499    }
1500
1501    fn debug(
1502        &self,
1503        bounds: RectF,
1504        _: &Self::LayoutState,
1505        _: &Self::PaintState,
1506        _: &V,
1507        cx: &ViewContext<V>,
1508    ) -> serde_json::Value {
1509        json!({
1510            "type": "ChildView",
1511            "bounds": bounds.to_json(),
1512            "child": if let Some(element) = cx.window.rendered_views.get(&self.view_id) {
1513                element.debug(&cx.window_context).log_err().unwrap_or_else(|| json!(null))
1514            } else {
1515                json!(null)
1516            }
1517        })
1518    }
1519}