window.rs

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