window.rs

   1use crate::{
   2    elements::AnyRootElement,
   3    geometry::{rect::RectF, Size},
   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::{
  37    tree::{Measurable, MeasureFunc},
  38    Taffy,
  39};
  40use util::ResultExt;
  41use uuid::Uuid;
  42
  43use super::{Reference, ViewMetadata};
  44
  45pub struct Window {
  46    layout_engines: Vec<LayoutEngine>,
  47    pub(crate) root_view: Option<AnyViewHandle>,
  48    pub(crate) focused_view_id: Option<usize>,
  49    pub(crate) parents: HashMap<usize, usize>,
  50    pub(crate) is_active: bool,
  51    pub(crate) is_fullscreen: bool,
  52    pub(crate) invalidation: Option<WindowInvalidation>,
  53    pub(crate) platform_window: Box<dyn platform::Window>,
  54    pub(crate) rendered_views: HashMap<usize, Box<dyn AnyRootElement>>,
  55    titlebar_height: f32,
  56    appearance: Appearance,
  57    cursor_regions: Vec<CursorRegion>,
  58    mouse_regions: Vec<(MouseRegion, usize)>,
  59    last_mouse_moved_event: Option<Event>,
  60    pub(crate) hovered_region_ids: Vec<MouseRegionId>,
  61    pub(crate) clicked_region_ids: Vec<MouseRegionId>,
  62    pub(crate) clicked_region: Option<(MouseRegionId, MouseButton)>,
  63    mouse_position: Vector2F,
  64    text_layout_cache: TextLayoutCache,
  65}
  66
  67impl Window {
  68    pub fn new<V, F>(
  69        handle: AnyWindowHandle,
  70        platform_window: Box<dyn platform::Window>,
  71        cx: &mut AppContext,
  72        build_view: F,
  73    ) -> Self
  74    where
  75        V: View,
  76        F: FnOnce(&mut ViewContext<V>) -> V,
  77    {
  78        let titlebar_height = platform_window.titlebar_height();
  79        let appearance = platform_window.appearance();
  80        let mut window = Self {
  81            layout_engines: Vec::new(),
  82            root_view: None,
  83            focused_view_id: None,
  84            parents: Default::default(),
  85            is_active: false,
  86            invalidation: None,
  87            is_fullscreen: false,
  88            platform_window,
  89            rendered_views: Default::default(),
  90            cursor_regions: Default::default(),
  91            mouse_regions: Default::default(),
  92            text_layout_cache: TextLayoutCache::new(cx.font_system.clone()),
  93            last_mouse_moved_event: None,
  94            hovered_region_ids: Default::default(),
  95            clicked_region_ids: Default::default(),
  96            clicked_region: None,
  97            mouse_position: vec2f(0., 0.),
  98            titlebar_height,
  99            appearance,
 100        };
 101
 102        let mut window_context = WindowContext::mutable(cx, &mut window, handle);
 103        let root_view = window_context.add_view(|cx| build_view(cx));
 104        if let Some(invalidation) = window_context.window.invalidation.take() {
 105            window_context.invalidate(invalidation, appearance);
 106        }
 107        window.focused_view_id = Some(root_view.id());
 108        window.root_view = Some(root_view.into_any());
 109        window
 110    }
 111
 112    pub fn root_view(&self) -> &AnyViewHandle {
 113        &self
 114            .root_view
 115            .as_ref()
 116            .expect("root_view called during window construction")
 117    }
 118}
 119
 120pub struct WindowContext<'a> {
 121    pub(crate) app_context: Reference<'a, AppContext>,
 122    pub(crate) window: Reference<'a, Window>,
 123    pub(crate) window_handle: AnyWindowHandle,
 124    pub(crate) removed: bool,
 125}
 126
 127impl Deref for WindowContext<'_> {
 128    type Target = AppContext;
 129
 130    fn deref(&self) -> &Self::Target {
 131        &self.app_context
 132    }
 133}
 134
 135impl DerefMut for WindowContext<'_> {
 136    fn deref_mut(&mut self) -> &mut Self::Target {
 137        &mut self.app_context
 138    }
 139}
 140
 141impl BorrowAppContext for WindowContext<'_> {
 142    fn read_with<T, F: FnOnce(&AppContext) -> T>(&self, f: F) -> T {
 143        self.app_context.read_with(f)
 144    }
 145
 146    fn update<T, F: FnOnce(&mut AppContext) -> T>(&mut self, f: F) -> T {
 147        self.app_context.update(f)
 148    }
 149}
 150
 151impl BorrowWindowContext for WindowContext<'_> {
 152    type Result<T> = T;
 153
 154    fn read_window<T, F: FnOnce(&WindowContext) -> T>(&self, handle: AnyWindowHandle, f: F) -> T {
 155        if self.window_handle == handle {
 156            f(self)
 157        } else {
 158            panic!("read_with called with id of window that does not belong to this context")
 159        }
 160    }
 161
 162    fn read_window_optional<T, F>(&self, window: AnyWindowHandle, f: F) -> Option<T>
 163    where
 164        F: FnOnce(&WindowContext) -> Option<T>,
 165    {
 166        BorrowWindowContext::read_window(self, window, f)
 167    }
 168
 169    fn update_window<T, F: FnOnce(&mut WindowContext) -> T>(
 170        &mut self,
 171        handle: AnyWindowHandle,
 172        f: F,
 173    ) -> T {
 174        if self.window_handle == handle {
 175            f(self)
 176        } else {
 177            panic!("update called with id of window that does not belong to this context")
 178        }
 179    }
 180
 181    fn update_window_optional<T, F>(&mut self, handle: AnyWindowHandle, f: F) -> Option<T>
 182    where
 183        F: FnOnce(&mut WindowContext) -> Option<T>,
 184    {
 185        BorrowWindowContext::update_window(self, handle, f)
 186    }
 187}
 188
 189impl<'a> WindowContext<'a> {
 190    pub fn mutable(
 191        app_context: &'a mut AppContext,
 192        window: &'a mut Window,
 193        handle: AnyWindowHandle,
 194    ) -> Self {
 195        Self {
 196            app_context: Reference::Mutable(app_context),
 197            window: Reference::Mutable(window),
 198            window_handle: handle,
 199            removed: false,
 200        }
 201    }
 202
 203    pub fn immutable(
 204        app_context: &'a AppContext,
 205        window: &'a Window,
 206        handle: AnyWindowHandle,
 207    ) -> Self {
 208        Self {
 209            app_context: Reference::Immutable(app_context),
 210            window: Reference::Immutable(window),
 211            window_handle: handle,
 212            removed: false,
 213        }
 214    }
 215
 216    pub fn layout_engine(&mut self) -> Option<&mut LayoutEngine> {
 217        self.window.layout_engines.last_mut()
 218    }
 219
 220    pub fn push_layout_engine(&mut self, engine: LayoutEngine) {
 221        self.window.layout_engines.push(engine);
 222    }
 223
 224    pub fn pop_layout_engine(&mut self) -> Option<LayoutEngine> {
 225        self.window.layout_engines.pop()
 226    }
 227
 228    pub fn remove_window(&mut self) {
 229        self.removed = true;
 230    }
 231
 232    pub fn window(&self) -> AnyWindowHandle {
 233        self.window_handle
 234    }
 235
 236    pub fn app_context(&mut self) -> &mut AppContext {
 237        &mut self.app_context
 238    }
 239
 240    pub fn root_view(&self) -> &AnyViewHandle {
 241        self.window.root_view()
 242    }
 243
 244    pub fn window_size(&self) -> Vector2F {
 245        self.window.platform_window.content_size()
 246    }
 247
 248    pub fn text_layout_cache(&self) -> &TextLayoutCache {
 249        &self.window.text_layout_cache
 250    }
 251
 252    pub(crate) fn update_any_view<F, T>(&mut self, view_id: usize, f: F) -> Option<T>
 253    where
 254        F: FnOnce(&mut dyn AnyView, &mut Self) -> T,
 255    {
 256        let handle = self.window_handle;
 257        let mut view = self.views.remove(&(handle, view_id))?;
 258        let result = f(view.as_mut(), self);
 259        self.views.insert((handle, view_id), view);
 260        Some(result)
 261    }
 262
 263    pub(crate) fn update_view<V: 'static, S>(
 264        &mut self,
 265        handle: &ViewHandle<V>,
 266        update: &mut dyn FnMut(&mut V, &mut ViewContext<V>) -> S,
 267    ) -> S {
 268        self.update_any_view(handle.view_id, |view, cx| {
 269            let mut cx = ViewContext::mutable(cx, handle.view_id);
 270            update(
 271                view.as_any_mut()
 272                    .downcast_mut()
 273                    .expect("downcast is type safe"),
 274                &mut cx,
 275            )
 276        })
 277        .expect("view is already on the stack")
 278    }
 279
 280    pub fn defer(&mut self, callback: impl 'static + FnOnce(&mut WindowContext)) {
 281        let handle = self.window_handle;
 282        self.app_context.defer(move |cx| {
 283            cx.update_window(handle, |cx| callback(cx));
 284        })
 285    }
 286
 287    pub fn update_global<T, F, U>(&mut self, update: F) -> U
 288    where
 289        T: 'static,
 290        F: FnOnce(&mut T, &mut Self) -> U,
 291    {
 292        AppContext::update_global_internal(self, |global, cx| update(global, cx))
 293    }
 294
 295    pub fn update_default_global<T, F, U>(&mut self, update: F) -> U
 296    where
 297        T: 'static + Default,
 298        F: FnOnce(&mut T, &mut Self) -> U,
 299    {
 300        AppContext::update_default_global_internal(self, |global, cx| update(global, cx))
 301    }
 302
 303    pub fn subscribe<E, H, F>(&mut self, handle: &H, mut callback: F) -> Subscription
 304    where
 305        E: Entity,
 306        E::Event: 'static,
 307        H: Handle<E>,
 308        F: 'static + FnMut(H, &E::Event, &mut WindowContext),
 309    {
 310        self.subscribe_internal(handle, move |emitter, event, cx| {
 311            callback(emitter, event, cx);
 312            true
 313        })
 314    }
 315
 316    pub fn subscribe_internal<E, H, F>(&mut self, handle: &H, mut callback: F) -> Subscription
 317    where
 318        E: Entity,
 319        E::Event: 'static,
 320        H: Handle<E>,
 321        F: 'static + FnMut(H, &E::Event, &mut WindowContext) -> bool,
 322    {
 323        let window_handle = self.window_handle;
 324        self.app_context
 325            .subscribe_internal(handle, move |emitter, event, cx| {
 326                cx.update_window(window_handle, |cx| callback(emitter, event, cx))
 327                    .unwrap_or(false)
 328            })
 329    }
 330
 331    pub(crate) fn observe_window_activation<F>(&mut self, callback: F) -> Subscription
 332    where
 333        F: 'static + FnMut(bool, &mut WindowContext) -> bool,
 334    {
 335        let handle = self.window_handle;
 336        let subscription_id = post_inc(&mut self.next_subscription_id);
 337        self.pending_effects
 338            .push_back(Effect::WindowActivationObservation {
 339                window: handle,
 340                subscription_id,
 341                callback: Box::new(callback),
 342            });
 343        Subscription::WindowActivationObservation(
 344            self.window_activation_observations
 345                .subscribe(handle, subscription_id),
 346        )
 347    }
 348
 349    pub(crate) fn observe_fullscreen<F>(&mut self, callback: F) -> Subscription
 350    where
 351        F: 'static + FnMut(bool, &mut WindowContext) -> bool,
 352    {
 353        let window = self.window_handle;
 354        let subscription_id = post_inc(&mut self.next_subscription_id);
 355        self.pending_effects
 356            .push_back(Effect::WindowFullscreenObservation {
 357                window,
 358                subscription_id,
 359                callback: Box::new(callback),
 360            });
 361        Subscription::WindowActivationObservation(
 362            self.window_activation_observations
 363                .subscribe(window, subscription_id),
 364        )
 365    }
 366
 367    pub(crate) fn observe_window_bounds<F>(&mut self, callback: F) -> Subscription
 368    where
 369        F: 'static + FnMut(WindowBounds, Uuid, &mut WindowContext) -> bool,
 370    {
 371        let window = self.window_handle;
 372        let subscription_id = post_inc(&mut self.next_subscription_id);
 373        self.pending_effects
 374            .push_back(Effect::WindowBoundsObservation {
 375                window,
 376                subscription_id,
 377                callback: Box::new(callback),
 378            });
 379        Subscription::WindowBoundsObservation(
 380            self.window_bounds_observations
 381                .subscribe(window, subscription_id),
 382        )
 383    }
 384
 385    pub fn observe_keystrokes<F>(&mut self, callback: F) -> Subscription
 386    where
 387        F: 'static
 388            + FnMut(&Keystroke, &MatchResult, Option<&Box<dyn Action>>, &mut WindowContext) -> bool,
 389    {
 390        let window = self.window_handle;
 391        let subscription_id = post_inc(&mut self.next_subscription_id);
 392        self.keystroke_observations
 393            .add_callback(window, subscription_id, Box::new(callback));
 394        Subscription::KeystrokeObservation(
 395            self.keystroke_observations
 396                .subscribe(window, subscription_id),
 397        )
 398    }
 399
 400    pub(crate) fn available_actions(
 401        &self,
 402        view_id: usize,
 403    ) -> Vec<(&'static str, Box<dyn Action>, SmallVec<[Binding; 1]>)> {
 404        let handle = self.window_handle;
 405        let mut contexts = Vec::new();
 406        let mut handler_depths_by_action_id = HashMap::<TypeId, usize>::default();
 407        for (depth, view_id) in self.ancestors(view_id).enumerate() {
 408            if let Some(view_metadata) = self.views_metadata.get(&(handle, view_id)) {
 409                contexts.push(view_metadata.keymap_context.clone());
 410                if let Some(actions) = self.actions.get(&view_metadata.type_id) {
 411                    handler_depths_by_action_id
 412                        .extend(actions.keys().copied().map(|action_id| (action_id, depth)));
 413                }
 414            } else {
 415                log::error!(
 416                    "view {} not found when computing available actions",
 417                    view_id
 418                );
 419            }
 420        }
 421
 422        handler_depths_by_action_id.extend(
 423            self.global_actions
 424                .keys()
 425                .copied()
 426                .map(|action_id| (action_id, contexts.len())),
 427        );
 428
 429        self.action_deserializers
 430            .iter()
 431            .filter_map(move |(name, (action_id, deserialize))| {
 432                if let Some(action_depth) = handler_depths_by_action_id.get(action_id).copied() {
 433                    let action = deserialize(serde_json::Value::Object(Default::default())).ok()?;
 434                    let bindings = self
 435                        .keystroke_matcher
 436                        .bindings_for_action(*action_id)
 437                        .filter(|b| {
 438                            action.eq(b.action())
 439                                && (0..=action_depth)
 440                                    .any(|depth| b.match_context(&contexts[depth..]))
 441                        })
 442                        .cloned()
 443                        .collect();
 444                    Some((*name, action, bindings))
 445                } else {
 446                    None
 447                }
 448            })
 449            .collect()
 450    }
 451
 452    pub(crate) fn dispatch_keystroke(&mut self, keystroke: &Keystroke) -> bool {
 453        let handle = self.window_handle;
 454        if let Some(focused_view_id) = self.focused_view_id() {
 455            let dispatch_path = self
 456                .ancestors(focused_view_id)
 457                .filter_map(|view_id| {
 458                    self.views_metadata
 459                        .get(&(handle, view_id))
 460                        .map(|view| (view_id, view.keymap_context.clone()))
 461                })
 462                .collect();
 463
 464            let match_result = self
 465                .keystroke_matcher
 466                .push_keystroke(keystroke.clone(), dispatch_path);
 467            let mut handled_by = None;
 468
 469            let keystroke_handled = match &match_result {
 470                MatchResult::None => false,
 471                MatchResult::Pending => true,
 472                MatchResult::Matches(matches) => {
 473                    for (view_id, action) in matches {
 474                        if self.dispatch_action(Some(*view_id), action.as_ref()) {
 475                            self.keystroke_matcher.clear_pending();
 476                            handled_by = Some(action.boxed_clone());
 477                            break;
 478                        }
 479                    }
 480                    handled_by.is_some()
 481                }
 482            };
 483
 484            self.keystroke(handle, keystroke.clone(), handled_by, match_result.clone());
 485            keystroke_handled
 486        } else {
 487            self.keystroke(handle, keystroke.clone(), None, MatchResult::None);
 488            false
 489        }
 490    }
 491
 492    pub(crate) fn dispatch_event(&mut self, event: Event, event_reused: bool) -> bool {
 493        let mut mouse_events = SmallVec::<[_; 2]>::new();
 494        let mut notified_views: HashSet<usize> = Default::default();
 495        let handle = self.window_handle;
 496
 497        // 1. Handle platform event. Keyboard events get dispatched immediately, while mouse events
 498        //    get mapped into the mouse-specific MouseEvent type.
 499        //  -> These are usually small: [Mouse Down] or [Mouse up, Click] or [Mouse Moved, Mouse Dragged?]
 500        //  -> Also updates mouse-related state
 501        match &event {
 502            Event::KeyDown(e) => return self.dispatch_key_down(e),
 503
 504            Event::KeyUp(e) => return self.dispatch_key_up(e),
 505
 506            Event::ModifiersChanged(e) => return self.dispatch_modifiers_changed(e),
 507
 508            Event::MouseDown(e) => {
 509                // Click events are weird because they can be fired after a drag event.
 510                // MDN says that browsers handle this by starting from 'the most
 511                // specific ancestor element that contained both [positions]'
 512                // So we need to store the overlapping regions on mouse down.
 513
 514                // If there is already region being clicked, don't replace it.
 515                if self.window.clicked_region.is_none() {
 516                    self.window.clicked_region_ids = self
 517                        .window
 518                        .mouse_regions
 519                        .iter()
 520                        .filter_map(|(region, _)| {
 521                            if region.bounds.contains_point(e.position) {
 522                                Some(region.id())
 523                            } else {
 524                                None
 525                            }
 526                        })
 527                        .collect();
 528
 529                    let mut highest_z_index = 0;
 530                    let mut clicked_region_id = None;
 531                    for (region, z_index) in self.window.mouse_regions.iter() {
 532                        if region.bounds.contains_point(e.position) && *z_index >= highest_z_index {
 533                            highest_z_index = *z_index;
 534                            clicked_region_id = Some(region.id());
 535                        }
 536                    }
 537
 538                    self.window.clicked_region =
 539                        clicked_region_id.map(|region_id| (region_id, e.button));
 540                }
 541
 542                mouse_events.push(MouseEvent::Down(MouseDown {
 543                    region: Default::default(),
 544                    platform_event: e.clone(),
 545                }));
 546                mouse_events.push(MouseEvent::DownOut(MouseDownOut {
 547                    region: Default::default(),
 548                    platform_event: e.clone(),
 549                }));
 550            }
 551
 552            Event::MouseUp(e) => {
 553                // NOTE: The order of event pushes is important! MouseUp events MUST be fired
 554                // before click events, and so the MouseUp events need to be pushed before
 555                // MouseClick events.
 556
 557                // Synthesize one last drag event to end the drag
 558                mouse_events.push(MouseEvent::Drag(MouseDrag {
 559                    region: Default::default(),
 560                    prev_mouse_position: self.window.mouse_position,
 561                    platform_event: MouseMovedEvent {
 562                        position: e.position,
 563                        pressed_button: Some(e.button),
 564                        modifiers: e.modifiers,
 565                    },
 566                    end: true,
 567                }));
 568                mouse_events.push(MouseEvent::Up(MouseUp {
 569                    region: Default::default(),
 570                    platform_event: e.clone(),
 571                }));
 572                mouse_events.push(MouseEvent::UpOut(MouseUpOut {
 573                    region: Default::default(),
 574                    platform_event: e.clone(),
 575                }));
 576                mouse_events.push(MouseEvent::Click(MouseClick {
 577                    region: Default::default(),
 578                    platform_event: e.clone(),
 579                }));
 580                mouse_events.push(MouseEvent::ClickOut(MouseClickOut {
 581                    region: Default::default(),
 582                    platform_event: e.clone(),
 583                }));
 584            }
 585
 586            Event::MouseMoved(
 587                e @ MouseMovedEvent {
 588                    position,
 589                    pressed_button,
 590                    ..
 591                },
 592            ) => {
 593                let mut style_to_assign = CursorStyle::Arrow;
 594                for region in self.window.cursor_regions.iter().rev() {
 595                    if region.bounds.contains_point(*position) {
 596                        style_to_assign = region.style;
 597                        break;
 598                    }
 599                }
 600
 601                if self
 602                    .window
 603                    .platform_window
 604                    .is_topmost_for_position(*position)
 605                {
 606                    self.platform().set_cursor_style(style_to_assign);
 607                }
 608
 609                if !event_reused {
 610                    if pressed_button.is_some() {
 611                        mouse_events.push(MouseEvent::Drag(MouseDrag {
 612                            region: Default::default(),
 613                            prev_mouse_position: self.window.mouse_position,
 614                            platform_event: e.clone(),
 615                            end: false,
 616                        }));
 617                    } else if let Some((_, clicked_button)) = self.window.clicked_region {
 618                        mouse_events.push(MouseEvent::Drag(MouseDrag {
 619                            region: Default::default(),
 620                            prev_mouse_position: self.window.mouse_position,
 621                            platform_event: e.clone(),
 622                            end: true,
 623                        }));
 624
 625                        // Mouse up event happened outside the current window. Simulate mouse up button event
 626                        let button_event = e.to_button_event(clicked_button);
 627                        mouse_events.push(MouseEvent::Up(MouseUp {
 628                            region: Default::default(),
 629                            platform_event: button_event.clone(),
 630                        }));
 631                        mouse_events.push(MouseEvent::UpOut(MouseUpOut {
 632                            region: Default::default(),
 633                            platform_event: button_event.clone(),
 634                        }));
 635                        mouse_events.push(MouseEvent::Click(MouseClick {
 636                            region: Default::default(),
 637                            platform_event: button_event.clone(),
 638                        }));
 639                    }
 640
 641                    mouse_events.push(MouseEvent::Move(MouseMove {
 642                        region: Default::default(),
 643                        platform_event: e.clone(),
 644                    }));
 645                }
 646
 647                mouse_events.push(MouseEvent::Hover(MouseHover {
 648                    region: Default::default(),
 649                    platform_event: e.clone(),
 650                    started: false,
 651                }));
 652                mouse_events.push(MouseEvent::MoveOut(MouseMoveOut {
 653                    region: Default::default(),
 654                }));
 655
 656                self.window.last_mouse_moved_event = Some(event.clone());
 657            }
 658
 659            Event::MouseExited(event) => {
 660                // When the platform sends a MouseExited event, synthesize
 661                // a MouseMoved event whose position is outside the window's
 662                // bounds so that hover and cursor state can be updated.
 663                return self.dispatch_event(
 664                    Event::MouseMoved(MouseMovedEvent {
 665                        position: event.position,
 666                        pressed_button: event.pressed_button,
 667                        modifiers: event.modifiers,
 668                    }),
 669                    event_reused,
 670                );
 671            }
 672
 673            Event::ScrollWheel(e) => mouse_events.push(MouseEvent::ScrollWheel(MouseScrollWheel {
 674                region: Default::default(),
 675                platform_event: e.clone(),
 676            })),
 677        }
 678
 679        if let Some(position) = event.position() {
 680            self.window.mouse_position = position;
 681        }
 682
 683        // 2. Dispatch mouse events on regions
 684        let mut any_event_handled = false;
 685        for mut mouse_event in mouse_events {
 686            let mut valid_regions = Vec::new();
 687
 688            // GPUI elements are arranged by z_index but sibling elements can register overlapping
 689            // mouse regions. As such, hover events are only fired on overlapping elements which
 690            // are at the same z-index as the topmost element which overlaps with the mouse.
 691            match &mouse_event {
 692                MouseEvent::Hover(_) => {
 693                    let mut highest_z_index = None;
 694                    let mouse_position = self.window.mouse_position.clone();
 695                    let window = &mut *self.window;
 696                    let prev_hovered_regions = mem::take(&mut window.hovered_region_ids);
 697                    for (region, z_index) in window.mouse_regions.iter().rev() {
 698                        // Allow mouse regions to appear transparent to hovers
 699                        if !region.hoverable {
 700                            continue;
 701                        }
 702
 703                        let contains_mouse = region.bounds.contains_point(mouse_position);
 704
 705                        if contains_mouse && highest_z_index.is_none() {
 706                            highest_z_index = Some(z_index);
 707                        }
 708
 709                        // This unwrap relies on short circuiting boolean expressions
 710                        // The right side of the && is only executed when contains_mouse
 711                        // is true, and we know above that when contains_mouse is true
 712                        // highest_z_index is set.
 713                        if contains_mouse && z_index == highest_z_index.unwrap() {
 714                            //Ensure that hover entrance events aren't sent twice
 715                            if let Err(ix) = window.hovered_region_ids.binary_search(&region.id()) {
 716                                window.hovered_region_ids.insert(ix, region.id());
 717                            }
 718                            // window.hovered_region_ids.insert(region.id());
 719                            if !prev_hovered_regions.contains(&region.id()) {
 720                                valid_regions.push(region.clone());
 721                                if region.notify_on_hover {
 722                                    notified_views.insert(region.id().view_id());
 723                                }
 724                            }
 725                        } else {
 726                            // Ensure that hover exit events aren't sent twice
 727                            if prev_hovered_regions.contains(&region.id()) {
 728                                valid_regions.push(region.clone());
 729                                if region.notify_on_hover {
 730                                    notified_views.insert(region.id().view_id());
 731                                }
 732                            }
 733                        }
 734                    }
 735                }
 736
 737                MouseEvent::Down(_) | MouseEvent::Up(_) => {
 738                    for (region, _) in self.window.mouse_regions.iter().rev() {
 739                        if region.bounds.contains_point(self.window.mouse_position) {
 740                            valid_regions.push(region.clone());
 741                            if region.notify_on_click {
 742                                notified_views.insert(region.id().view_id());
 743                            }
 744                        }
 745                    }
 746                }
 747
 748                MouseEvent::Click(e) => {
 749                    // Only raise click events if the released button is the same as the one stored
 750                    if self
 751                        .window
 752                        .clicked_region
 753                        .map(|(_, clicked_button)| clicked_button == e.button)
 754                        .unwrap_or(false)
 755                    {
 756                        // Clear clicked regions and clicked button
 757                        let clicked_region_ids = std::mem::replace(
 758                            &mut self.window.clicked_region_ids,
 759                            Default::default(),
 760                        );
 761                        self.window.clicked_region = None;
 762
 763                        // Find regions which still overlap with the mouse since the last MouseDown happened
 764                        for (mouse_region, _) in self.window.mouse_regions.iter().rev() {
 765                            if clicked_region_ids.contains(&mouse_region.id()) {
 766                                if mouse_region
 767                                    .bounds
 768                                    .contains_point(self.window.mouse_position)
 769                                {
 770                                    valid_regions.push(mouse_region.clone());
 771                                }
 772                            }
 773                        }
 774                    }
 775                }
 776
 777                MouseEvent::Drag(_) => {
 778                    for (mouse_region, _) in self.window.mouse_regions.iter().rev() {
 779                        if self.window.clicked_region_ids.contains(&mouse_region.id()) {
 780                            valid_regions.push(mouse_region.clone());
 781                        }
 782                    }
 783                }
 784
 785                MouseEvent::MoveOut(_)
 786                | MouseEvent::UpOut(_)
 787                | MouseEvent::DownOut(_)
 788                | MouseEvent::ClickOut(_) => {
 789                    for (mouse_region, _) in self.window.mouse_regions.iter().rev() {
 790                        // NOT contains
 791                        if !mouse_region
 792                            .bounds
 793                            .contains_point(self.window.mouse_position)
 794                        {
 795                            valid_regions.push(mouse_region.clone());
 796                        }
 797                    }
 798                }
 799
 800                _ => {
 801                    for (mouse_region, _) in self.window.mouse_regions.iter().rev() {
 802                        // Contains
 803                        if mouse_region
 804                            .bounds
 805                            .contains_point(self.window.mouse_position)
 806                        {
 807                            valid_regions.push(mouse_region.clone());
 808                        }
 809                    }
 810                }
 811            }
 812
 813            //3. Fire region events
 814            let hovered_region_ids = self.window.hovered_region_ids.clone();
 815            for valid_region in valid_regions.into_iter() {
 816                let mut handled = false;
 817                mouse_event.set_region(valid_region.bounds);
 818                if let MouseEvent::Hover(e) = &mut mouse_event {
 819                    e.started = hovered_region_ids.contains(&valid_region.id())
 820                }
 821                // Handle Down events if the MouseRegion has a Click or Drag handler. This makes the api more intuitive as you would
 822                // not expect a MouseRegion to be transparent to Down events if it also has a Click handler.
 823                // This behavior can be overridden by adding a Down handler
 824                if let MouseEvent::Down(e) = &mouse_event {
 825                    let has_click = valid_region
 826                        .handlers
 827                        .contains(MouseEvent::click_disc(), Some(e.button));
 828                    let has_drag = valid_region
 829                        .handlers
 830                        .contains(MouseEvent::drag_disc(), Some(e.button));
 831                    let has_down = valid_region
 832                        .handlers
 833                        .contains(MouseEvent::down_disc(), Some(e.button));
 834                    if !has_down && (has_click || has_drag) {
 835                        handled = true;
 836                    }
 837                }
 838
 839                // `event_consumed` should only be true if there are any handlers for this event.
 840                let mut event_consumed = handled;
 841                if let Some(callbacks) = valid_region.handlers.get(&mouse_event.handler_key()) {
 842                    for callback in callbacks {
 843                        handled = true;
 844                        let view_id = valid_region.id().view_id();
 845                        self.update_any_view(view_id, |view, cx| {
 846                            handled = callback(mouse_event.clone(), view.as_any_mut(), cx, view_id);
 847                        });
 848                        event_consumed |= handled;
 849                        any_event_handled |= handled;
 850                    }
 851                }
 852
 853                any_event_handled |= handled;
 854
 855                // For bubbling events, if the event was handled, don't continue dispatching.
 856                // This only makes sense for local events which return false from is_capturable.
 857                if event_consumed && mouse_event.is_capturable() {
 858                    break;
 859                }
 860            }
 861        }
 862
 863        for view_id in notified_views {
 864            self.notify_view(handle, view_id);
 865        }
 866
 867        any_event_handled
 868    }
 869
 870    pub(crate) fn dispatch_key_down(&mut self, event: &KeyDownEvent) -> bool {
 871        let handle = self.window_handle;
 872        if let Some(focused_view_id) = self.window.focused_view_id {
 873            for view_id in self.ancestors(focused_view_id).collect::<Vec<_>>() {
 874                if let Some(mut view) = self.views.remove(&(handle, view_id)) {
 875                    let handled = view.key_down(event, self, view_id);
 876                    self.views.insert((handle, view_id), view);
 877                    if handled {
 878                        return true;
 879                    }
 880                } else {
 881                    log::error!("view {} does not exist", view_id)
 882                }
 883            }
 884        }
 885
 886        false
 887    }
 888
 889    pub(crate) fn dispatch_key_up(&mut self, event: &KeyUpEvent) -> bool {
 890        let handle = self.window_handle;
 891        if let Some(focused_view_id) = self.window.focused_view_id {
 892            for view_id in self.ancestors(focused_view_id).collect::<Vec<_>>() {
 893                if let Some(mut view) = self.views.remove(&(handle, view_id)) {
 894                    let handled = view.key_up(event, self, view_id);
 895                    self.views.insert((handle, view_id), view);
 896                    if handled {
 897                        return true;
 898                    }
 899                } else {
 900                    log::error!("view {} does not exist", view_id)
 901                }
 902            }
 903        }
 904
 905        false
 906    }
 907
 908    pub(crate) fn dispatch_modifiers_changed(&mut self, event: &ModifiersChangedEvent) -> bool {
 909        let handle = self.window_handle;
 910        if let Some(focused_view_id) = self.window.focused_view_id {
 911            for view_id in self.ancestors(focused_view_id).collect::<Vec<_>>() {
 912                if let Some(mut view) = self.views.remove(&(handle, view_id)) {
 913                    let handled = view.modifiers_changed(event, self, view_id);
 914                    self.views.insert((handle, view_id), view);
 915                    if handled {
 916                        return true;
 917                    }
 918                } else {
 919                    log::error!("view {} does not exist", view_id)
 920                }
 921            }
 922        }
 923
 924        false
 925    }
 926
 927    pub fn invalidate(&mut self, mut invalidation: WindowInvalidation, appearance: Appearance) {
 928        self.start_frame();
 929        self.window.appearance = appearance;
 930        for view_id in &invalidation.removed {
 931            invalidation.updated.remove(view_id);
 932            self.window.rendered_views.remove(view_id);
 933        }
 934        for view_id in &invalidation.updated {
 935            let titlebar_height = self.window.titlebar_height;
 936            let element = self
 937                .render_view(RenderParams {
 938                    view_id: *view_id,
 939                    titlebar_height,
 940                    refreshing: false,
 941                    appearance,
 942                })
 943                .unwrap();
 944            self.window.rendered_views.insert(*view_id, element);
 945        }
 946    }
 947
 948    pub fn render_view(&mut self, params: RenderParams) -> Result<Box<dyn AnyRootElement>> {
 949        let handle = self.window_handle;
 950        let view_id = params.view_id;
 951        let mut view = self
 952            .views
 953            .remove(&(handle, view_id))
 954            .ok_or_else(|| anyhow!("view not found"))?;
 955        let element = view.render(self, view_id);
 956        self.views.insert((handle, view_id), view);
 957        Ok(element)
 958    }
 959
 960    pub fn layout(&mut self, refreshing: bool) -> Result<HashMap<usize, usize>> {
 961        let window_size = self.window.platform_window.content_size();
 962        let root_view_id = self.window.root_view().id();
 963
 964        let mut rendered_root = self.window.rendered_views.remove(&root_view_id).unwrap();
 965
 966        let mut new_parents = HashMap::default();
 967        let mut views_to_notify_if_ancestors_change = HashMap::default();
 968        rendered_root.layout(
 969            SizeConstraint::new(window_size, window_size),
 970            &mut new_parents,
 971            &mut views_to_notify_if_ancestors_change,
 972            refreshing,
 973            self,
 974        )?;
 975
 976        for (view_id, view_ids_to_notify) in views_to_notify_if_ancestors_change {
 977            let mut current_view_id = view_id;
 978            loop {
 979                let old_parent_id = self.window.parents.get(&current_view_id);
 980                let new_parent_id = new_parents.get(&current_view_id);
 981                if old_parent_id.is_none() && new_parent_id.is_none() {
 982                    break;
 983                } else if old_parent_id == new_parent_id {
 984                    current_view_id = *old_parent_id.unwrap();
 985                } else {
 986                    let handle = self.window_handle;
 987                    for view_id_to_notify in view_ids_to_notify {
 988                        self.notify_view(handle, view_id_to_notify);
 989                    }
 990                    break;
 991                }
 992            }
 993        }
 994
 995        let old_parents = mem::replace(&mut self.window.parents, new_parents);
 996        self.window
 997            .rendered_views
 998            .insert(root_view_id, rendered_root);
 999        Ok(old_parents)
1000    }
1001
1002    pub fn paint(&mut self) -> Result<Scene> {
1003        let window_size = self.window.platform_window.content_size();
1004        let scale_factor = self.window.platform_window.scale_factor();
1005
1006        let root_view_id = self.window.root_view().id();
1007        let mut rendered_root = self.window.rendered_views.remove(&root_view_id).unwrap();
1008
1009        let mut scene_builder = SceneBuilder::new(scale_factor);
1010        rendered_root.paint(
1011            &mut scene_builder,
1012            Vector2F::zero(),
1013            RectF::from_points(Vector2F::zero(), window_size),
1014            self,
1015        )?;
1016        self.window
1017            .rendered_views
1018            .insert(root_view_id, rendered_root);
1019
1020        self.window.text_layout_cache.finish_frame();
1021        let scene = scene_builder.build();
1022        self.window.cursor_regions = scene.cursor_regions();
1023        self.window.mouse_regions = scene.mouse_regions();
1024
1025        if self.window_is_active() {
1026            if let Some(event) = self.window.last_mouse_moved_event.clone() {
1027                self.dispatch_event(event, true);
1028            }
1029        }
1030
1031        Ok(scene)
1032    }
1033
1034    pub fn root_element(&self) -> &Box<dyn AnyRootElement> {
1035        let view_id = self.window.root_view().id();
1036        self.window.rendered_views.get(&view_id).unwrap()
1037    }
1038
1039    pub fn rect_for_text_range(&self, range_utf16: Range<usize>) -> Option<RectF> {
1040        let focused_view_id = self.window.focused_view_id?;
1041        self.window
1042            .rendered_views
1043            .get(&focused_view_id)?
1044            .rect_for_text_range(range_utf16, self)
1045            .log_err()
1046            .flatten()
1047    }
1048
1049    pub fn set_window_title(&mut self, title: &str) {
1050        self.window.platform_window.set_title(title);
1051    }
1052
1053    pub fn set_window_edited(&mut self, edited: bool) {
1054        self.window.platform_window.set_edited(edited);
1055    }
1056
1057    pub fn is_topmost_window_for_position(&self, position: Vector2F) -> bool {
1058        self.window
1059            .platform_window
1060            .is_topmost_for_position(position)
1061    }
1062
1063    pub fn activate_window(&self) {
1064        self.window.platform_window.activate();
1065    }
1066
1067    pub fn window_is_active(&self) -> bool {
1068        self.window.is_active
1069    }
1070
1071    pub fn window_is_fullscreen(&self) -> bool {
1072        self.window.is_fullscreen
1073    }
1074
1075    pub(crate) fn dispatch_action(&mut self, view_id: Option<usize>, action: &dyn Action) -> bool {
1076        if let Some(view_id) = view_id {
1077            self.halt_action_dispatch = false;
1078            self.visit_dispatch_path(view_id, |view_id, capture_phase, cx| {
1079                cx.update_any_view(view_id, |view, cx| {
1080                    let type_id = view.as_any().type_id();
1081                    if let Some((name, mut handlers)) = cx
1082                        .actions_mut(capture_phase)
1083                        .get_mut(&type_id)
1084                        .and_then(|h| h.remove_entry(&action.id()))
1085                    {
1086                        for handler in handlers.iter_mut().rev() {
1087                            cx.halt_action_dispatch = true;
1088                            handler(view, action, cx, view_id);
1089                            if cx.halt_action_dispatch {
1090                                break;
1091                            }
1092                        }
1093                        cx.actions_mut(capture_phase)
1094                            .get_mut(&type_id)
1095                            .unwrap()
1096                            .insert(name, handlers);
1097                    }
1098                });
1099
1100                !cx.halt_action_dispatch
1101            });
1102        }
1103
1104        if !self.halt_action_dispatch {
1105            self.halt_action_dispatch = self.dispatch_global_action_any(action);
1106        }
1107
1108        self.pending_effects
1109            .push_back(Effect::ActionDispatchNotification {
1110                action_id: action.id(),
1111            });
1112        self.halt_action_dispatch
1113    }
1114
1115    /// Returns an iterator over all of the view ids from the passed view up to the root of the window
1116    /// Includes the passed view itself
1117    pub(crate) fn ancestors(&self, mut view_id: usize) -> impl Iterator<Item = usize> + '_ {
1118        std::iter::once(view_id)
1119            .into_iter()
1120            .chain(std::iter::from_fn(move || {
1121                if let Some(parent_id) = self.window.parents.get(&view_id) {
1122                    view_id = *parent_id;
1123                    Some(view_id)
1124                } else {
1125                    None
1126                }
1127            }))
1128    }
1129
1130    // Traverses the parent tree. Walks down the tree toward the passed
1131    // view calling visit with true. Then walks back up the tree calling visit with false.
1132    // If `visit` returns false this function will immediately return.
1133    fn visit_dispatch_path(
1134        &mut self,
1135        view_id: usize,
1136        mut visit: impl FnMut(usize, bool, &mut WindowContext) -> bool,
1137    ) {
1138        // List of view ids from the leaf to the root of the window
1139        let path = self.ancestors(view_id).collect::<Vec<_>>();
1140
1141        // Walk down from the root to the leaf calling visit with capture_phase = true
1142        for view_id in path.iter().rev() {
1143            if !visit(*view_id, true, self) {
1144                return;
1145            }
1146        }
1147
1148        // Walk up from the leaf to the root calling visit with capture_phase = false
1149        for view_id in path.iter() {
1150            if !visit(*view_id, false, self) {
1151                return;
1152            }
1153        }
1154    }
1155
1156    pub fn focused_view_id(&self) -> Option<usize> {
1157        self.window.focused_view_id
1158    }
1159
1160    pub fn focus(&mut self, view_id: Option<usize>) {
1161        self.app_context.focus(self.window_handle, view_id);
1162    }
1163
1164    pub fn window_bounds(&self) -> WindowBounds {
1165        self.window.platform_window.bounds()
1166    }
1167
1168    pub fn window_appearance(&self) -> Appearance {
1169        self.window.appearance
1170    }
1171
1172    pub fn window_display_uuid(&self) -> Option<Uuid> {
1173        self.window.platform_window.screen().display_uuid()
1174    }
1175
1176    pub fn show_character_palette(&self) {
1177        self.window.platform_window.show_character_palette();
1178    }
1179
1180    pub fn minimize_window(&self) {
1181        self.window.platform_window.minimize();
1182    }
1183
1184    pub fn zoom_window(&self) {
1185        self.window.platform_window.zoom();
1186    }
1187
1188    pub fn toggle_full_screen(&self) {
1189        self.window.platform_window.toggle_full_screen();
1190    }
1191
1192    pub fn prompt(
1193        &self,
1194        level: PromptLevel,
1195        msg: &str,
1196        answers: &[&str],
1197    ) -> oneshot::Receiver<usize> {
1198        self.window.platform_window.prompt(level, msg, answers)
1199    }
1200
1201    pub fn add_view<T, F>(&mut self, build_view: F) -> ViewHandle<T>
1202    where
1203        T: View,
1204        F: FnOnce(&mut ViewContext<T>) -> T,
1205    {
1206        self.add_option_view(|cx| Some(build_view(cx))).unwrap()
1207    }
1208
1209    pub fn add_option_view<T, F>(&mut self, build_view: F) -> Option<ViewHandle<T>>
1210    where
1211        T: View,
1212        F: FnOnce(&mut ViewContext<T>) -> Option<T>,
1213    {
1214        let handle = self.window_handle;
1215        let view_id = post_inc(&mut self.next_id);
1216        let mut cx = ViewContext::mutable(self, view_id);
1217        let handle = if let Some(view) = build_view(&mut cx) {
1218            let mut keymap_context = KeymapContext::default();
1219            view.update_keymap_context(&mut keymap_context, cx.app_context());
1220            self.views_metadata.insert(
1221                (handle, view_id),
1222                ViewMetadata {
1223                    type_id: TypeId::of::<T>(),
1224                    keymap_context,
1225                },
1226            );
1227            self.views.insert((handle, view_id), Box::new(view));
1228            self.window
1229                .invalidation
1230                .get_or_insert_with(Default::default)
1231                .updated
1232                .insert(view_id);
1233            Some(ViewHandle::new(handle, view_id, &self.ref_counts))
1234        } else {
1235            None
1236        };
1237        handle
1238    }
1239}
1240
1241#[derive(Default)]
1242pub struct LayoutEngine(Taffy);
1243pub use taffy::style::Style as LayoutStyle;
1244
1245impl LayoutEngine {
1246    pub fn new() -> Self {
1247        Default::default()
1248    }
1249
1250    pub fn add_node<C>(&mut self, style: LayoutStyle, children: C) -> Result<LayoutNodeId>
1251    where
1252        C: IntoIterator<Item = LayoutNodeId>,
1253    {
1254        Ok(self
1255            .0
1256            .new_with_children(style, &children.into_iter().collect::<Vec<_>>())?)
1257    }
1258
1259    pub fn add_measured_node<F>(&mut self, style: LayoutStyle, measure: F) -> Result<LayoutNodeId>
1260    where
1261        F: Fn(MeasureParams) -> Size<f32> + Sync + Send + 'static,
1262    {
1263        Ok(self
1264            .0
1265            .new_leaf_with_measure(style, MeasureFunc::Boxed(Box::new(MeasureFn(measure))))?)
1266    }
1267
1268    pub fn compute_layout(&mut self, root: LayoutNodeId, available_space: Vector2F) -> Result<()> {
1269        self.0.compute_layout(
1270            root,
1271            taffy::geometry::Size {
1272                width: available_space.x().into(),
1273                height: available_space.y().into(),
1274            },
1275        )?;
1276        Ok(())
1277    }
1278
1279    pub fn computed_layout(&mut self, node: LayoutNodeId) -> Result<EngineLayout> {
1280        Ok(self.0.layout(node)?.into())
1281    }
1282}
1283
1284pub struct MeasureFn<F>(F);
1285
1286impl<F: Send + Sync> Measurable for MeasureFn<F>
1287where
1288    F: Fn(MeasureParams) -> Size<f32>,
1289{
1290    fn measure(
1291        &self,
1292        known_dimensions: taffy::prelude::Size<Option<f32>>,
1293        available_space: taffy::prelude::Size<taffy::style::AvailableSpace>,
1294    ) -> taffy::prelude::Size<f32> {
1295        (self.0)(MeasureParams {
1296            known_dimensions: known_dimensions.into(),
1297            available_space: available_space.into(),
1298        })
1299        .into()
1300    }
1301}
1302
1303pub struct EngineLayout {
1304    pub bounds: RectF,
1305    pub order: u32,
1306}
1307
1308pub struct MeasureParams {
1309    pub known_dimensions: Size<Option<f32>>,
1310    pub available_space: Size<AvailableSpace>,
1311}
1312
1313pub enum AvailableSpace {
1314    /// The amount of space available is the specified number of pixels
1315    Pixels(f32),
1316    /// The amount of space available is indefinite and the node should be laid out under a min-content constraint
1317    MinContent,
1318    /// The amount of space available is indefinite and the node should be laid out under a max-content constraint
1319    MaxContent,
1320}
1321
1322impl From<taffy::prelude::AvailableSpace> for AvailableSpace {
1323    fn from(value: taffy::prelude::AvailableSpace) -> Self {
1324        match value {
1325            taffy::prelude::AvailableSpace::Definite(pixels) => Self::Pixels(pixels),
1326            taffy::prelude::AvailableSpace::MinContent => Self::MinContent,
1327            taffy::prelude::AvailableSpace::MaxContent => Self::MaxContent,
1328        }
1329    }
1330}
1331
1332impl From<&taffy::tree::Layout> for EngineLayout {
1333    fn from(value: &taffy::tree::Layout) -> Self {
1334        Self {
1335            bounds: RectF::new(
1336                vec2f(value.location.x, value.location.y),
1337                vec2f(value.size.width, value.size.height),
1338            ),
1339            order: value.order,
1340        }
1341    }
1342}
1343
1344pub type LayoutNodeId = taffy::prelude::NodeId;
1345
1346pub struct RenderParams {
1347    pub view_id: usize,
1348    pub titlebar_height: f32,
1349    pub refreshing: bool,
1350    pub appearance: Appearance,
1351}
1352
1353#[derive(Clone, Copy, Debug, Default, Eq, PartialEq)]
1354pub enum Axis {
1355    #[default]
1356    Horizontal,
1357    Vertical,
1358}
1359
1360impl Axis {
1361    pub fn invert(self) -> Self {
1362        match self {
1363            Self::Horizontal => Self::Vertical,
1364            Self::Vertical => Self::Horizontal,
1365        }
1366    }
1367
1368    pub fn component(&self, point: Vector2F) -> f32 {
1369        match self {
1370            Self::Horizontal => point.x(),
1371            Self::Vertical => point.y(),
1372        }
1373    }
1374}
1375
1376impl ToJson for Axis {
1377    fn to_json(&self) -> serde_json::Value {
1378        match self {
1379            Axis::Horizontal => json!("horizontal"),
1380            Axis::Vertical => json!("vertical"),
1381        }
1382    }
1383}
1384
1385impl StaticColumnCount for Axis {}
1386impl Bind for Axis {
1387    fn bind(&self, statement: &Statement, start_index: i32) -> anyhow::Result<i32> {
1388        match self {
1389            Axis::Horizontal => "Horizontal",
1390            Axis::Vertical => "Vertical",
1391        }
1392        .bind(statement, start_index)
1393    }
1394}
1395
1396impl Column for Axis {
1397    fn column(statement: &mut Statement, start_index: i32) -> anyhow::Result<(Self, i32)> {
1398        String::column(statement, start_index).and_then(|(axis_text, next_index)| {
1399            Ok((
1400                match axis_text.as_str() {
1401                    "Horizontal" => Axis::Horizontal,
1402                    "Vertical" => Axis::Vertical,
1403                    _ => bail!("Stored serialized item kind is incorrect"),
1404                },
1405                next_index,
1406            ))
1407        })
1408    }
1409}
1410
1411pub trait Vector2FExt {
1412    fn along(self, axis: Axis) -> f32;
1413}
1414
1415impl Vector2FExt for Vector2F {
1416    fn along(self, axis: Axis) -> f32 {
1417        match axis {
1418            Axis::Horizontal => self.x(),
1419            Axis::Vertical => self.y(),
1420        }
1421    }
1422}
1423
1424pub trait RectFExt {
1425    fn length_along(self, axis: Axis) -> f32;
1426}
1427
1428impl RectFExt for RectF {
1429    fn length_along(self, axis: Axis) -> f32 {
1430        match axis {
1431            Axis::Horizontal => self.width(),
1432            Axis::Vertical => self.height(),
1433        }
1434    }
1435}
1436
1437#[derive(Copy, Clone, Debug)]
1438pub struct SizeConstraint {
1439    pub min: Vector2F,
1440    pub max: Vector2F,
1441}
1442
1443impl SizeConstraint {
1444    pub fn new(min: Vector2F, max: Vector2F) -> Self {
1445        Self { min, max }
1446    }
1447
1448    pub fn strict(size: Vector2F) -> Self {
1449        Self {
1450            min: size,
1451            max: size,
1452        }
1453    }
1454    pub fn loose(max: Vector2F) -> Self {
1455        Self {
1456            min: Vector2F::zero(),
1457            max,
1458        }
1459    }
1460
1461    pub fn strict_along(axis: Axis, max: f32) -> Self {
1462        match axis {
1463            Axis::Horizontal => Self {
1464                min: vec2f(max, 0.0),
1465                max: vec2f(max, f32::INFINITY),
1466            },
1467            Axis::Vertical => Self {
1468                min: vec2f(0.0, max),
1469                max: vec2f(f32::INFINITY, max),
1470            },
1471        }
1472    }
1473
1474    pub fn max_along(&self, axis: Axis) -> f32 {
1475        match axis {
1476            Axis::Horizontal => self.max.x(),
1477            Axis::Vertical => self.max.y(),
1478        }
1479    }
1480
1481    pub fn min_along(&self, axis: Axis) -> f32 {
1482        match axis {
1483            Axis::Horizontal => self.min.x(),
1484            Axis::Vertical => self.min.y(),
1485        }
1486    }
1487
1488    pub fn constrain(&self, size: Vector2F) -> Vector2F {
1489        vec2f(
1490            size.x().min(self.max.x()).max(self.min.x()),
1491            size.y().min(self.max.y()).max(self.min.y()),
1492        )
1493    }
1494}
1495
1496impl Sub<Vector2F> for SizeConstraint {
1497    type Output = SizeConstraint;
1498
1499    fn sub(self, rhs: Vector2F) -> SizeConstraint {
1500        SizeConstraint {
1501            min: self.min - rhs,
1502            max: self.max - rhs,
1503        }
1504    }
1505}
1506
1507impl Default for SizeConstraint {
1508    fn default() -> Self {
1509        SizeConstraint {
1510            min: Vector2F::zero(),
1511            max: Vector2F::splat(f32::INFINITY),
1512        }
1513    }
1514}
1515
1516impl ToJson for SizeConstraint {
1517    fn to_json(&self) -> serde_json::Value {
1518        json!({
1519            "min": self.min.to_json(),
1520            "max": self.max.to_json(),
1521        })
1522    }
1523}
1524
1525#[derive(Clone)]
1526pub struct ChildView {
1527    view_id: usize,
1528    view_name: &'static str,
1529}
1530
1531impl ChildView {
1532    pub fn new(view: &AnyViewHandle, cx: &AppContext) -> Self {
1533        let view_name = cx.view_ui_name(view.window, view.id()).unwrap();
1534        Self {
1535            view_id: view.id(),
1536            view_name,
1537        }
1538    }
1539}
1540
1541impl<V: 'static> Element<V> for ChildView {
1542    type LayoutState = ();
1543    type PaintState = ();
1544
1545    fn layout(
1546        &mut self,
1547        constraint: SizeConstraint,
1548        _: &mut V,
1549        cx: &mut LayoutContext<V>,
1550    ) -> (Vector2F, Self::LayoutState) {
1551        if let Some(mut rendered_view) = cx.window.rendered_views.remove(&self.view_id) {
1552            cx.new_parents.insert(self.view_id, cx.view_id());
1553            let size = rendered_view
1554                .layout(
1555                    constraint,
1556                    cx.new_parents,
1557                    cx.views_to_notify_if_ancestors_change,
1558                    cx.refreshing,
1559                    cx.view_context,
1560                )
1561                .log_err()
1562                .unwrap_or(Vector2F::zero());
1563            cx.window.rendered_views.insert(self.view_id, rendered_view);
1564            (size, ())
1565        } else {
1566            log::error!(
1567                "layout called on a ChildView element whose underlying view was dropped (view_id: {}, name: {:?})",
1568                self.view_id,
1569                self.view_name
1570            );
1571            (Vector2F::zero(), ())
1572        }
1573    }
1574
1575    fn paint(
1576        &mut self,
1577        scene: &mut SceneBuilder,
1578        bounds: RectF,
1579        visible_bounds: RectF,
1580        _: &mut Self::LayoutState,
1581        _: &mut V,
1582        cx: &mut PaintContext<V>,
1583    ) {
1584        if let Some(mut rendered_view) = cx.window.rendered_views.remove(&self.view_id) {
1585            rendered_view
1586                .paint(scene, bounds.origin(), visible_bounds, cx)
1587                .log_err();
1588            cx.window.rendered_views.insert(self.view_id, rendered_view);
1589        } else {
1590            log::error!(
1591                "paint called on a ChildView element whose underlying view was dropped (view_id: {}, name: {:?})",
1592                self.view_id,
1593                self.view_name
1594            );
1595        }
1596    }
1597
1598    fn rect_for_text_range(
1599        &self,
1600        range_utf16: Range<usize>,
1601        _: RectF,
1602        _: RectF,
1603        _: &Self::LayoutState,
1604        _: &Self::PaintState,
1605        _: &V,
1606        cx: &ViewContext<V>,
1607    ) -> Option<RectF> {
1608        if let Some(rendered_view) = cx.window.rendered_views.get(&self.view_id) {
1609            rendered_view
1610                .rect_for_text_range(range_utf16, &cx.window_context)
1611                .log_err()
1612                .flatten()
1613        } else {
1614            log::error!(
1615                "rect_for_text_range called on a ChildView element whose underlying view was dropped (view_id: {}, name: {:?})",
1616                self.view_id,
1617                self.view_name
1618            );
1619            None
1620        }
1621    }
1622
1623    fn debug(
1624        &self,
1625        bounds: RectF,
1626        _: &Self::LayoutState,
1627        _: &Self::PaintState,
1628        _: &V,
1629        cx: &ViewContext<V>,
1630    ) -> serde_json::Value {
1631        json!({
1632            "type": "ChildView",
1633            "bounds": bounds.to_json(),
1634            "child": if let Some(element) = cx.window.rendered_views.get(&self.view_id) {
1635                element.debug(&cx.window_context).log_err().unwrap_or_else(|| json!(null))
1636            } else {
1637                json!(null)
1638            }
1639        })
1640    }
1641}