window.rs

   1use crate::{
   2    elements::AnyRootElement,
   3    fonts::{TextStyle, TextStyleRefinement},
   4    geometry::{rect::RectF, Size},
   5    json::ToJson,
   6    keymap_matcher::{Binding, KeymapContext, Keystroke, MatchResult},
   7    platform::{
   8        self, Appearance, CursorStyle, Event, KeyDownEvent, KeyUpEvent, ModifiersChangedEvent,
   9        MouseButton, MouseMovedEvent, PromptLevel, WindowBounds,
  10    },
  11    scene::{
  12        CursorRegion, EventHandler, MouseClick, MouseClickOut, MouseDown, MouseDownOut, MouseDrag,
  13        MouseEvent, MouseHover, MouseMove, MouseMoveOut, MouseScrollWheel, MouseUp, MouseUpOut,
  14        Scene,
  15    },
  16    text_layout::TextLayoutCache,
  17    util::post_inc,
  18    Action, AnyView, AnyViewHandle, AnyWindowHandle, AppContext, BorrowAppContext,
  19    BorrowWindowContext, Effect, Element, Entity, Handle, LayoutContext, MouseRegion,
  20    MouseRegionId, PaintContext, SceneBuilder, Subscription, View, ViewContext, ViewHandle,
  21    WindowInvalidation,
  22};
  23use anyhow::{anyhow, bail, Result};
  24use collections::{HashMap, HashSet};
  25use pathfinder_geometry::vector::{vec2f, Vector2F};
  26use postage::oneshot;
  27use serde_json::json;
  28use smallvec::SmallVec;
  29use sqlez::{
  30    bindable::{Bind, Column, StaticColumnCount},
  31    statement::Statement,
  32};
  33use std::{
  34    any::{type_name, Any, TypeId},
  35    mem,
  36    ops::{Deref, DerefMut, Range, Sub},
  37};
  38use taffy::{
  39    tree::{Measurable, MeasureFunc},
  40    Taffy,
  41};
  42use util::ResultExt;
  43use uuid::Uuid;
  44
  45use super::{Reference, ViewMetadata};
  46
  47pub struct Window {
  48    layout_engines: Vec<LayoutEngine>,
  49    pub(crate) root_view: Option<AnyViewHandle>,
  50    pub(crate) focused_view_id: Option<usize>,
  51    pub(crate) parents: HashMap<usize, usize>,
  52    pub(crate) is_active: bool,
  53    pub(crate) is_fullscreen: bool,
  54    inspector_enabled: bool,
  55    pub(crate) invalidation: Option<WindowInvalidation>,
  56    pub(crate) platform_window: Box<dyn platform::Window>,
  57    pub(crate) rendered_views: HashMap<usize, Box<dyn AnyRootElement>>,
  58    pub(crate) text_style_stack: Vec<TextStyle>,
  59    pub(crate) theme_stack: Vec<Box<dyn Any>>,
  60    pub(crate) new_parents: HashMap<usize, usize>,
  61    pub(crate) views_to_notify_if_ancestors_change: HashMap<usize, SmallVec<[usize; 2]>>,
  62    titlebar_height: f32,
  63    appearance: Appearance,
  64    cursor_regions: Vec<CursorRegion>,
  65    mouse_regions: Vec<(MouseRegion, usize)>,
  66    event_handlers: Vec<EventHandler>,
  67    last_mouse_moved_event: Option<Event>,
  68    last_mouse_position: Vector2F,
  69    pressed_buttons: HashSet<MouseButton>,
  70    pub(crate) hovered_region_ids: Vec<MouseRegionId>,
  71    pub(crate) clicked_region_ids: Vec<MouseRegionId>,
  72    pub(crate) clicked_region: Option<(MouseRegionId, MouseButton)>,
  73    text_layout_cache: TextLayoutCache,
  74}
  75
  76impl Window {
  77    pub fn new<V, F>(
  78        handle: AnyWindowHandle,
  79        platform_window: Box<dyn platform::Window>,
  80        cx: &mut AppContext,
  81        build_view: F,
  82    ) -> Self
  83    where
  84        V: View,
  85        F: FnOnce(&mut ViewContext<V>) -> V,
  86    {
  87        let titlebar_height = platform_window.titlebar_height();
  88        let appearance = platform_window.appearance();
  89        let mut window = Self {
  90            layout_engines: Vec::new(),
  91            root_view: None,
  92            focused_view_id: None,
  93            parents: Default::default(),
  94            is_active: false,
  95            invalidation: None,
  96            is_fullscreen: false,
  97            inspector_enabled: false,
  98            platform_window,
  99            rendered_views: Default::default(),
 100            text_style_stack: Vec::new(),
 101            theme_stack: Vec::new(),
 102            new_parents: HashMap::default(),
 103            views_to_notify_if_ancestors_change: HashMap::default(),
 104            cursor_regions: Default::default(),
 105            mouse_regions: Default::default(),
 106            event_handlers: Default::default(),
 107            text_layout_cache: TextLayoutCache::new(cx.font_system.clone()),
 108            last_mouse_moved_event: None,
 109            last_mouse_position: Vector2F::zero(),
 110            pressed_buttons: Default::default(),
 111            hovered_region_ids: Default::default(),
 112            clicked_region_ids: Default::default(),
 113            clicked_region: None,
 114            titlebar_height,
 115            appearance,
 116        };
 117
 118        let mut window_context = WindowContext::mutable(cx, &mut window, handle);
 119        let root_view = window_context.add_view(|cx| build_view(cx));
 120        if let Some(invalidation) = window_context.window.invalidation.take() {
 121            window_context.invalidate(invalidation, appearance);
 122        }
 123        window.focused_view_id = Some(root_view.id());
 124        window.root_view = Some(root_view.into_any());
 125        window
 126    }
 127
 128    pub fn root_view(&self) -> &AnyViewHandle {
 129        &self
 130            .root_view
 131            .as_ref()
 132            .expect("root_view called during window construction")
 133    }
 134
 135    pub fn take_event_handlers(&mut self) -> Vec<EventHandler> {
 136        mem::take(&mut self.event_handlers)
 137    }
 138}
 139
 140pub struct WindowContext<'a> {
 141    pub(crate) app_context: Reference<'a, AppContext>,
 142    pub(crate) window: Reference<'a, Window>,
 143    pub(crate) window_handle: AnyWindowHandle,
 144    pub(crate) removed: bool,
 145}
 146
 147impl Deref for WindowContext<'_> {
 148    type Target = AppContext;
 149
 150    fn deref(&self) -> &Self::Target {
 151        &self.app_context
 152    }
 153}
 154
 155impl DerefMut for WindowContext<'_> {
 156    fn deref_mut(&mut self) -> &mut Self::Target {
 157        &mut self.app_context
 158    }
 159}
 160
 161impl BorrowAppContext for WindowContext<'_> {
 162    fn read_with<T, F: FnOnce(&AppContext) -> T>(&self, f: F) -> T {
 163        self.app_context.read_with(f)
 164    }
 165
 166    fn update<T, F: FnOnce(&mut AppContext) -> T>(&mut self, f: F) -> T {
 167        self.app_context.update(f)
 168    }
 169}
 170
 171impl BorrowWindowContext for WindowContext<'_> {
 172    type Result<T> = T;
 173
 174    fn read_window<T, F: FnOnce(&WindowContext) -> T>(&self, handle: AnyWindowHandle, f: F) -> T {
 175        if self.window_handle == handle {
 176            f(self)
 177        } else {
 178            panic!("read_with called with id of window that does not belong to this context")
 179        }
 180    }
 181
 182    fn read_window_optional<T, F>(&self, window: AnyWindowHandle, f: F) -> Option<T>
 183    where
 184        F: FnOnce(&WindowContext) -> Option<T>,
 185    {
 186        BorrowWindowContext::read_window(self, window, f)
 187    }
 188
 189    fn update_window<T, F: FnOnce(&mut WindowContext) -> T>(
 190        &mut self,
 191        handle: AnyWindowHandle,
 192        f: F,
 193    ) -> T {
 194        if self.window_handle == handle {
 195            f(self)
 196        } else {
 197            panic!("update called with id of window that does not belong to this context")
 198        }
 199    }
 200
 201    fn update_window_optional<T, F>(&mut self, handle: AnyWindowHandle, f: F) -> Option<T>
 202    where
 203        F: FnOnce(&mut WindowContext) -> Option<T>,
 204    {
 205        BorrowWindowContext::update_window(self, handle, f)
 206    }
 207}
 208
 209impl<'a> WindowContext<'a> {
 210    pub fn mutable(
 211        app_context: &'a mut AppContext,
 212        window: &'a mut Window,
 213        handle: AnyWindowHandle,
 214    ) -> Self {
 215        Self {
 216            app_context: Reference::Mutable(app_context),
 217            window: Reference::Mutable(window),
 218            window_handle: handle,
 219            removed: false,
 220        }
 221    }
 222
 223    pub fn immutable(
 224        app_context: &'a AppContext,
 225        window: &'a Window,
 226        handle: AnyWindowHandle,
 227    ) -> Self {
 228        Self {
 229            app_context: Reference::Immutable(app_context),
 230            window: Reference::Immutable(window),
 231            window_handle: handle,
 232            removed: false,
 233        }
 234    }
 235
 236    pub fn repaint(&mut self) {
 237        let window = self.window();
 238        self.pending_effects
 239            .push_back(Effect::RepaintWindow { window });
 240    }
 241
 242    pub fn enable_inspector(&mut self) {
 243        self.window.inspector_enabled = true;
 244    }
 245
 246    pub fn is_inspector_enabled(&self) -> bool {
 247        self.window.inspector_enabled
 248    }
 249
 250    pub fn is_mouse_down(&self, button: MouseButton) -> bool {
 251        self.window.pressed_buttons.contains(&button)
 252    }
 253
 254    pub fn rem_size(&self) -> f32 {
 255        16.
 256    }
 257
 258    pub fn layout_engine(&mut self) -> Option<&mut LayoutEngine> {
 259        self.window.layout_engines.last_mut()
 260    }
 261
 262    pub fn push_layout_engine(&mut self, engine: LayoutEngine) {
 263        self.window.layout_engines.push(engine);
 264    }
 265
 266    pub fn pop_layout_engine(&mut self) -> Option<LayoutEngine> {
 267        self.window.layout_engines.pop()
 268    }
 269
 270    pub fn remove_window(&mut self) {
 271        self.removed = true;
 272    }
 273
 274    pub fn window(&self) -> AnyWindowHandle {
 275        self.window_handle
 276    }
 277
 278    pub fn app_context(&mut self) -> &mut AppContext {
 279        &mut self.app_context
 280    }
 281
 282    pub fn root_view(&self) -> &AnyViewHandle {
 283        self.window.root_view()
 284    }
 285
 286    pub fn window_size(&self) -> Vector2F {
 287        self.window.platform_window.content_size()
 288    }
 289
 290    pub fn mouse_position(&self) -> Vector2F {
 291        self.window.platform_window.mouse_position()
 292    }
 293
 294    pub fn text_layout_cache(&self) -> &TextLayoutCache {
 295        &self.window.text_layout_cache
 296    }
 297
 298    pub(crate) fn update_any_view<F, T>(&mut self, view_id: usize, f: F) -> Option<T>
 299    where
 300        F: FnOnce(&mut dyn AnyView, &mut Self) -> T,
 301    {
 302        let handle = self.window_handle;
 303        let mut view = self.views.remove(&(handle, view_id))?;
 304        let result = f(view.as_mut(), self);
 305        self.views.insert((handle, view_id), view);
 306        Some(result)
 307    }
 308
 309    pub(crate) fn update_view<V: 'static, S>(
 310        &mut self,
 311        handle: &ViewHandle<V>,
 312        update: &mut dyn FnMut(&mut V, &mut ViewContext<V>) -> S,
 313    ) -> S {
 314        self.update_any_view(handle.view_id, |view, cx| {
 315            let mut cx = ViewContext::mutable(cx, handle.view_id);
 316            update(
 317                view.as_any_mut()
 318                    .downcast_mut()
 319                    .expect("downcast is type safe"),
 320                &mut cx,
 321            )
 322        })
 323        .expect("view is already on the stack")
 324    }
 325
 326    pub fn defer(&mut self, callback: impl 'static + FnOnce(&mut WindowContext)) {
 327        let handle = self.window_handle;
 328        self.app_context.defer(move |cx| {
 329            cx.update_window(handle, |cx| callback(cx));
 330        })
 331    }
 332
 333    pub fn update_global<T, F, U>(&mut self, update: F) -> U
 334    where
 335        T: 'static,
 336        F: FnOnce(&mut T, &mut Self) -> U,
 337    {
 338        AppContext::update_global_internal(self, |global, cx| update(global, cx))
 339    }
 340
 341    pub fn update_default_global<T, F, U>(&mut self, update: F) -> U
 342    where
 343        T: 'static + Default,
 344        F: FnOnce(&mut T, &mut Self) -> U,
 345    {
 346        AppContext::update_default_global_internal(self, |global, cx| update(global, cx))
 347    }
 348
 349    pub fn subscribe<E, H, F>(&mut self, handle: &H, mut callback: F) -> Subscription
 350    where
 351        E: Entity,
 352        E::Event: 'static,
 353        H: Handle<E>,
 354        F: 'static + FnMut(H, &E::Event, &mut WindowContext),
 355    {
 356        self.subscribe_internal(handle, move |emitter, event, cx| {
 357            callback(emitter, event, cx);
 358            true
 359        })
 360    }
 361
 362    pub fn subscribe_internal<E, H, F>(&mut self, handle: &H, mut callback: F) -> Subscription
 363    where
 364        E: Entity,
 365        E::Event: 'static,
 366        H: Handle<E>,
 367        F: 'static + FnMut(H, &E::Event, &mut WindowContext) -> bool,
 368    {
 369        let window_handle = self.window_handle;
 370        self.app_context
 371            .subscribe_internal(handle, move |emitter, event, cx| {
 372                cx.update_window(window_handle, |cx| callback(emitter, event, cx))
 373                    .unwrap_or(false)
 374            })
 375    }
 376
 377    pub(crate) fn observe_window_activation<F>(&mut self, callback: F) -> Subscription
 378    where
 379        F: 'static + FnMut(bool, &mut WindowContext) -> bool,
 380    {
 381        let handle = self.window_handle;
 382        let subscription_id = post_inc(&mut self.next_subscription_id);
 383        self.pending_effects
 384            .push_back(Effect::WindowActivationObservation {
 385                window: handle,
 386                subscription_id,
 387                callback: Box::new(callback),
 388            });
 389        Subscription::WindowActivationObservation(
 390            self.window_activation_observations
 391                .subscribe(handle, subscription_id),
 392        )
 393    }
 394
 395    pub(crate) fn observe_fullscreen<F>(&mut self, callback: F) -> Subscription
 396    where
 397        F: 'static + FnMut(bool, &mut WindowContext) -> bool,
 398    {
 399        let window = self.window_handle;
 400        let subscription_id = post_inc(&mut self.next_subscription_id);
 401        self.pending_effects
 402            .push_back(Effect::WindowFullscreenObservation {
 403                window,
 404                subscription_id,
 405                callback: Box::new(callback),
 406            });
 407        Subscription::WindowActivationObservation(
 408            self.window_activation_observations
 409                .subscribe(window, subscription_id),
 410        )
 411    }
 412
 413    pub(crate) fn observe_window_bounds<F>(&mut self, callback: F) -> Subscription
 414    where
 415        F: 'static + FnMut(WindowBounds, Uuid, &mut WindowContext) -> bool,
 416    {
 417        let window = self.window_handle;
 418        let subscription_id = post_inc(&mut self.next_subscription_id);
 419        self.pending_effects
 420            .push_back(Effect::WindowBoundsObservation {
 421                window,
 422                subscription_id,
 423                callback: Box::new(callback),
 424            });
 425        Subscription::WindowBoundsObservation(
 426            self.window_bounds_observations
 427                .subscribe(window, subscription_id),
 428        )
 429    }
 430
 431    pub fn observe_keystrokes<F>(&mut self, callback: F) -> Subscription
 432    where
 433        F: 'static
 434            + FnMut(&Keystroke, &MatchResult, Option<&Box<dyn Action>>, &mut WindowContext) -> bool,
 435    {
 436        let window = self.window_handle;
 437        let subscription_id = post_inc(&mut self.next_subscription_id);
 438        self.keystroke_observations
 439            .add_callback(window, subscription_id, Box::new(callback));
 440        Subscription::KeystrokeObservation(
 441            self.keystroke_observations
 442                .subscribe(window, subscription_id),
 443        )
 444    }
 445
 446    pub(crate) fn available_actions(
 447        &self,
 448        view_id: usize,
 449    ) -> Vec<(&'static str, Box<dyn Action>, SmallVec<[Binding; 1]>)> {
 450        let handle = self.window_handle;
 451        let mut contexts = Vec::new();
 452        let mut handler_depths_by_action_id = HashMap::<TypeId, usize>::default();
 453        for (depth, view_id) in self.ancestors(view_id).enumerate() {
 454            if let Some(view_metadata) = self.views_metadata.get(&(handle, view_id)) {
 455                contexts.push(view_metadata.keymap_context.clone());
 456                if let Some(actions) = self.actions.get(&view_metadata.type_id) {
 457                    handler_depths_by_action_id
 458                        .extend(actions.keys().copied().map(|action_id| (action_id, depth)));
 459                }
 460            } else {
 461                log::error!(
 462                    "view {} not found when computing available actions",
 463                    view_id
 464                );
 465            }
 466        }
 467
 468        handler_depths_by_action_id.extend(
 469            self.global_actions
 470                .keys()
 471                .copied()
 472                .map(|action_id| (action_id, contexts.len())),
 473        );
 474
 475        self.action_deserializers
 476            .iter()
 477            .filter_map(move |(name, (action_id, deserialize))| {
 478                if let Some(action_depth) = handler_depths_by_action_id.get(action_id).copied() {
 479                    let action = deserialize(serde_json::Value::Object(Default::default())).ok()?;
 480                    let bindings = self
 481                        .keystroke_matcher
 482                        .bindings_for_action(*action_id)
 483                        .filter(|b| {
 484                            action.eq(b.action())
 485                                && (0..=action_depth)
 486                                    .any(|depth| b.match_context(&contexts[depth..]))
 487                        })
 488                        .cloned()
 489                        .collect();
 490                    Some((*name, action, bindings))
 491                } else {
 492                    None
 493                }
 494            })
 495            .collect()
 496    }
 497
 498    pub(crate) fn dispatch_keystroke(&mut self, keystroke: &Keystroke) -> bool {
 499        let handle = self.window_handle;
 500        if let Some(focused_view_id) = self.focused_view_id() {
 501            let dispatch_path = self
 502                .ancestors(focused_view_id)
 503                .filter_map(|view_id| {
 504                    self.views_metadata
 505                        .get(&(handle, view_id))
 506                        .map(|view| (view_id, view.keymap_context.clone()))
 507                })
 508                .collect();
 509
 510            let match_result = self
 511                .keystroke_matcher
 512                .push_keystroke(keystroke.clone(), dispatch_path);
 513            let mut handled_by = None;
 514
 515            let keystroke_handled = match &match_result {
 516                MatchResult::None => false,
 517                MatchResult::Pending => true,
 518                MatchResult::Matches(matches) => {
 519                    for (view_id, action) in matches {
 520                        if self.dispatch_action(Some(*view_id), action.as_ref()) {
 521                            self.keystroke_matcher.clear_pending();
 522                            handled_by = Some(action.boxed_clone());
 523                            break;
 524                        }
 525                    }
 526                    handled_by.is_some()
 527                }
 528            };
 529
 530            self.keystroke(handle, keystroke.clone(), handled_by, match_result.clone());
 531            keystroke_handled
 532        } else {
 533            self.keystroke(handle, keystroke.clone(), None, MatchResult::None);
 534            false
 535        }
 536    }
 537
 538    pub(crate) fn dispatch_event(&mut self, event: Event, event_reused: bool) -> bool {
 539        if !event_reused {
 540            self.dispatch_event_2(&event);
 541        }
 542
 543        let mut mouse_events = SmallVec::<[_; 2]>::new();
 544        let mut notified_views: HashSet<usize> = Default::default();
 545        let handle = self.window_handle;
 546
 547        // 1. Handle platform event. Keyboard events get dispatched immediately, while mouse events
 548        //    get mapped into the mouse-specific MouseEvent type.
 549        //  -> These are usually small: [Mouse Down] or [Mouse up, Click] or [Mouse Moved, Mouse Dragged?]
 550        //  -> Also updates mouse-related state
 551        match &event {
 552            Event::KeyDown(e) => return self.dispatch_key_down(e),
 553
 554            Event::KeyUp(e) => return self.dispatch_key_up(e),
 555
 556            Event::ModifiersChanged(e) => return self.dispatch_modifiers_changed(e),
 557
 558            Event::MouseDown(e) => {
 559                // Click events are weird because they can be fired after a drag event.
 560                // MDN says that browsers handle this by starting from 'the most
 561                // specific ancestor element that contained both [positions]'
 562                // So we need to store the overlapping regions on mouse down.
 563
 564                // If there is already region being clicked, don't replace it.
 565                if self.window.clicked_region.is_none() {
 566                    self.window.clicked_region_ids = self
 567                        .window
 568                        .mouse_regions
 569                        .iter()
 570                        .filter_map(|(region, _)| {
 571                            if region.bounds.contains_point(e.position) {
 572                                Some(region.id())
 573                            } else {
 574                                None
 575                            }
 576                        })
 577                        .collect();
 578
 579                    let mut highest_z_index = 0;
 580                    let mut clicked_region_id = None;
 581                    for (region, z_index) in self.window.mouse_regions.iter() {
 582                        if region.bounds.contains_point(e.position) && *z_index >= highest_z_index {
 583                            highest_z_index = *z_index;
 584                            clicked_region_id = Some(region.id());
 585                        }
 586                    }
 587
 588                    self.window.clicked_region =
 589                        clicked_region_id.map(|region_id| (region_id, e.button));
 590                }
 591
 592                mouse_events.push(MouseEvent::Down(MouseDown {
 593                    region: Default::default(),
 594                    platform_event: e.clone(),
 595                }));
 596                mouse_events.push(MouseEvent::DownOut(MouseDownOut {
 597                    region: Default::default(),
 598                    platform_event: e.clone(),
 599                }));
 600            }
 601
 602            Event::MouseUp(e) => {
 603                // NOTE: The order of event pushes is important! MouseUp events MUST be fired
 604                // before click events, and so the MouseUp events need to be pushed before
 605                // MouseClick events.
 606
 607                // Synthesize one last drag event to end the drag
 608                mouse_events.push(MouseEvent::Drag(MouseDrag {
 609                    region: Default::default(),
 610                    prev_mouse_position: self.window.last_mouse_position,
 611                    platform_event: MouseMovedEvent {
 612                        position: e.position,
 613                        pressed_button: Some(e.button),
 614                        modifiers: e.modifiers,
 615                    },
 616                    end: true,
 617                }));
 618                mouse_events.push(MouseEvent::Up(MouseUp {
 619                    region: Default::default(),
 620                    platform_event: e.clone(),
 621                }));
 622                mouse_events.push(MouseEvent::UpOut(MouseUpOut {
 623                    region: Default::default(),
 624                    platform_event: e.clone(),
 625                }));
 626                mouse_events.push(MouseEvent::Click(MouseClick {
 627                    region: Default::default(),
 628                    platform_event: e.clone(),
 629                }));
 630                mouse_events.push(MouseEvent::ClickOut(MouseClickOut {
 631                    region: Default::default(),
 632                    platform_event: e.clone(),
 633                }));
 634            }
 635
 636            Event::MouseMoved(
 637                e @ MouseMovedEvent {
 638                    position,
 639                    pressed_button,
 640                    ..
 641                },
 642            ) => {
 643                let mut style_to_assign = CursorStyle::Arrow;
 644                for region in self.window.cursor_regions.iter().rev() {
 645                    if region.bounds.contains_point(*position) {
 646                        style_to_assign = region.style;
 647                        break;
 648                    }
 649                }
 650
 651                if pressed_button.is_none()
 652                    && self
 653                        .window
 654                        .platform_window
 655                        .is_topmost_for_position(*position)
 656                {
 657                    self.platform().set_cursor_style(style_to_assign);
 658                }
 659
 660                if !event_reused {
 661                    if pressed_button.is_some() {
 662                        mouse_events.push(MouseEvent::Drag(MouseDrag {
 663                            region: Default::default(),
 664                            prev_mouse_position: self.window.last_mouse_position,
 665                            platform_event: e.clone(),
 666                            end: false,
 667                        }));
 668                    } else if let Some((_, clicked_button)) = self.window.clicked_region {
 669                        mouse_events.push(MouseEvent::Drag(MouseDrag {
 670                            region: Default::default(),
 671                            prev_mouse_position: self.window.last_mouse_position,
 672                            platform_event: e.clone(),
 673                            end: true,
 674                        }));
 675
 676                        // Mouse up event happened outside the current window. Simulate mouse up button event
 677                        let button_event = e.to_button_event(clicked_button);
 678                        mouse_events.push(MouseEvent::Up(MouseUp {
 679                            region: Default::default(),
 680                            platform_event: button_event.clone(),
 681                        }));
 682                        mouse_events.push(MouseEvent::UpOut(MouseUpOut {
 683                            region: Default::default(),
 684                            platform_event: button_event.clone(),
 685                        }));
 686                        mouse_events.push(MouseEvent::Click(MouseClick {
 687                            region: Default::default(),
 688                            platform_event: button_event.clone(),
 689                        }));
 690                    }
 691
 692                    mouse_events.push(MouseEvent::Move(MouseMove {
 693                        region: Default::default(),
 694                        platform_event: e.clone(),
 695                    }));
 696                }
 697
 698                mouse_events.push(MouseEvent::Hover(MouseHover {
 699                    region: Default::default(),
 700                    platform_event: e.clone(),
 701                    started: false,
 702                }));
 703                mouse_events.push(MouseEvent::MoveOut(MouseMoveOut {
 704                    region: Default::default(),
 705                }));
 706
 707                self.window.last_mouse_moved_event = Some(event.clone());
 708            }
 709
 710            Event::MouseExited(event) => {
 711                // When the platform sends a MouseExited event, synthesize
 712                // a MouseMoved event whose position is outside the window's
 713                // bounds so that hover and cursor state can be updated.
 714                return self.dispatch_event(
 715                    Event::MouseMoved(MouseMovedEvent {
 716                        position: event.position,
 717                        pressed_button: event.pressed_button,
 718                        modifiers: event.modifiers,
 719                    }),
 720                    event_reused,
 721                );
 722            }
 723
 724            Event::ScrollWheel(e) => mouse_events.push(MouseEvent::ScrollWheel(MouseScrollWheel {
 725                region: Default::default(),
 726                platform_event: e.clone(),
 727            })),
 728        }
 729
 730        if let Some(position) = event.position() {
 731            self.window.last_mouse_position = position;
 732        }
 733
 734        // 2. Dispatch mouse events on regions
 735        let mut any_event_handled = false;
 736        for mut mouse_event in mouse_events {
 737            let mut valid_regions = Vec::new();
 738
 739            // GPUI elements are arranged by z_index but sibling elements can register overlapping
 740            // mouse regions. As such, hover events are only fired on overlapping elements which
 741            // are at the same z-index as the topmost element which overlaps with the mouse.
 742            match &mouse_event {
 743                MouseEvent::Hover(_) => {
 744                    let mut highest_z_index = None;
 745                    let mouse_position = self.mouse_position();
 746                    let window = &mut *self.window;
 747                    let prev_hovered_regions = mem::take(&mut window.hovered_region_ids);
 748                    for (region, z_index) in window.mouse_regions.iter().rev() {
 749                        // Allow mouse regions to appear transparent to hovers
 750                        if !region.hoverable {
 751                            continue;
 752                        }
 753
 754                        let contains_mouse = region.bounds.contains_point(mouse_position);
 755
 756                        if contains_mouse && highest_z_index.is_none() {
 757                            highest_z_index = Some(z_index);
 758                        }
 759
 760                        // This unwrap relies on short circuiting boolean expressions
 761                        // The right side of the && is only executed when contains_mouse
 762                        // is true, and we know above that when contains_mouse is true
 763                        // highest_z_index is set.
 764                        if contains_mouse && z_index == highest_z_index.unwrap() {
 765                            //Ensure that hover entrance events aren't sent twice
 766                            if let Err(ix) = window.hovered_region_ids.binary_search(&region.id()) {
 767                                window.hovered_region_ids.insert(ix, region.id());
 768                            }
 769                            // window.hovered_region_ids.insert(region.id());
 770                            if !prev_hovered_regions.contains(&region.id()) {
 771                                valid_regions.push(region.clone());
 772                                if region.notify_on_hover {
 773                                    notified_views.insert(region.id().view_id());
 774                                }
 775                            }
 776                        } else {
 777                            // Ensure that hover exit events aren't sent twice
 778                            if prev_hovered_regions.contains(&region.id()) {
 779                                valid_regions.push(region.clone());
 780                                if region.notify_on_hover {
 781                                    notified_views.insert(region.id().view_id());
 782                                }
 783                            }
 784                        }
 785                    }
 786                }
 787
 788                MouseEvent::Down(_) | MouseEvent::Up(_) => {
 789                    for (region, _) in self.window.mouse_regions.iter().rev() {
 790                        if region.bounds.contains_point(self.mouse_position()) {
 791                            valid_regions.push(region.clone());
 792                            if region.notify_on_click {
 793                                notified_views.insert(region.id().view_id());
 794                            }
 795                        }
 796                    }
 797                }
 798
 799                MouseEvent::Click(e) => {
 800                    // Only raise click events if the released button is the same as the one stored
 801                    if self
 802                        .window
 803                        .clicked_region
 804                        .map(|(_, clicked_button)| clicked_button == e.button)
 805                        .unwrap_or(false)
 806                    {
 807                        // Clear clicked regions and clicked button
 808                        let clicked_region_ids = std::mem::replace(
 809                            &mut self.window.clicked_region_ids,
 810                            Default::default(),
 811                        );
 812                        self.window.clicked_region = None;
 813
 814                        // Find regions which still overlap with the mouse since the last MouseDown happened
 815                        for (mouse_region, _) in self.window.mouse_regions.iter().rev() {
 816                            if clicked_region_ids.contains(&mouse_region.id()) {
 817                                if mouse_region.bounds.contains_point(self.mouse_position()) {
 818                                    valid_regions.push(mouse_region.clone());
 819                                } else {
 820                                    // Let the view know that it hasn't been clicked anymore
 821                                    if mouse_region.notify_on_click {
 822                                        notified_views.insert(mouse_region.id().view_id());
 823                                    }
 824                                }
 825                            }
 826                        }
 827                    }
 828                }
 829
 830                MouseEvent::Drag(_) => {
 831                    for (mouse_region, _) in self.window.mouse_regions.iter().rev() {
 832                        if self.window.clicked_region_ids.contains(&mouse_region.id()) {
 833                            valid_regions.push(mouse_region.clone());
 834                        }
 835                    }
 836                }
 837
 838                MouseEvent::MoveOut(_)
 839                | MouseEvent::UpOut(_)
 840                | MouseEvent::DownOut(_)
 841                | MouseEvent::ClickOut(_) => {
 842                    for (mouse_region, _) in self.window.mouse_regions.iter().rev() {
 843                        // NOT contains
 844                        if !mouse_region.bounds.contains_point(self.mouse_position()) {
 845                            valid_regions.push(mouse_region.clone());
 846                        }
 847                    }
 848                }
 849
 850                _ => {
 851                    for (mouse_region, _) in self.window.mouse_regions.iter().rev() {
 852                        // Contains
 853                        if mouse_region.bounds.contains_point(self.mouse_position()) {
 854                            valid_regions.push(mouse_region.clone());
 855                        }
 856                    }
 857                }
 858            }
 859
 860            //3. Fire region events
 861            let hovered_region_ids = self.window.hovered_region_ids.clone();
 862            for valid_region in valid_regions.into_iter() {
 863                let mut handled = false;
 864                mouse_event.set_region(valid_region.bounds);
 865                if let MouseEvent::Hover(e) = &mut mouse_event {
 866                    e.started = hovered_region_ids.contains(&valid_region.id())
 867                }
 868                // Handle Down events if the MouseRegion has a Click or Drag handler. This makes the api more intuitive as you would
 869                // not expect a MouseRegion to be transparent to Down events if it also has a Click handler.
 870                // This behavior can be overridden by adding a Down handler
 871                if let MouseEvent::Down(e) = &mouse_event {
 872                    let has_click = valid_region
 873                        .handlers
 874                        .contains(MouseEvent::click_disc(), Some(e.button));
 875                    let has_drag = valid_region
 876                        .handlers
 877                        .contains(MouseEvent::drag_disc(), Some(e.button));
 878                    let has_down = valid_region
 879                        .handlers
 880                        .contains(MouseEvent::down_disc(), Some(e.button));
 881                    if !has_down && (has_click || has_drag) {
 882                        handled = true;
 883                    }
 884                }
 885
 886                // `event_consumed` should only be true if there are any handlers for this event.
 887                let mut event_consumed = handled;
 888                if let Some(callbacks) = valid_region.handlers.get(&mouse_event.handler_key()) {
 889                    for callback in callbacks {
 890                        handled = true;
 891                        let view_id = valid_region.id().view_id();
 892                        self.update_any_view(view_id, |view, cx| {
 893                            handled = callback(mouse_event.clone(), view.as_any_mut(), cx, view_id);
 894                        });
 895                        event_consumed |= handled;
 896                        any_event_handled |= handled;
 897                    }
 898                }
 899
 900                any_event_handled |= handled;
 901
 902                // For bubbling events, if the event was handled, don't continue dispatching.
 903                // This only makes sense for local events which return false from is_capturable.
 904                if event_consumed && mouse_event.is_capturable() {
 905                    break;
 906                }
 907            }
 908        }
 909
 910        for view_id in notified_views {
 911            self.notify_view(handle, view_id);
 912        }
 913
 914        any_event_handled
 915    }
 916
 917    fn dispatch_event_2(&mut self, event: &Event) {
 918        match event {
 919            Event::MouseDown(event) => {
 920                self.window.pressed_buttons.insert(event.button);
 921            }
 922            Event::MouseUp(event) => {
 923                self.window.pressed_buttons.remove(&event.button);
 924            }
 925            _ => {}
 926        }
 927
 928        if let Some(mouse_event) = event.mouse_event() {
 929            let event_handlers = self.window.take_event_handlers();
 930            for event_handler in event_handlers.iter().rev() {
 931                if event_handler.event_type == mouse_event.type_id() {
 932                    if !(event_handler.handler)(mouse_event, self) {
 933                        break;
 934                    }
 935                }
 936            }
 937            self.window.event_handlers = event_handlers;
 938        }
 939    }
 940
 941    pub(crate) fn dispatch_key_down(&mut self, event: &KeyDownEvent) -> bool {
 942        let handle = self.window_handle;
 943        if let Some(focused_view_id) = self.window.focused_view_id {
 944            for view_id in self.ancestors(focused_view_id).collect::<Vec<_>>() {
 945                if let Some(mut view) = self.views.remove(&(handle, view_id)) {
 946                    let handled = view.key_down(event, self, view_id);
 947                    self.views.insert((handle, view_id), view);
 948                    if handled {
 949                        return true;
 950                    }
 951                } else {
 952                    log::error!("view {} does not exist", view_id)
 953                }
 954            }
 955        }
 956
 957        false
 958    }
 959
 960    pub(crate) fn dispatch_key_up(&mut self, event: &KeyUpEvent) -> bool {
 961        let handle = self.window_handle;
 962        if let Some(focused_view_id) = self.window.focused_view_id {
 963            for view_id in self.ancestors(focused_view_id).collect::<Vec<_>>() {
 964                if let Some(mut view) = self.views.remove(&(handle, view_id)) {
 965                    let handled = view.key_up(event, self, view_id);
 966                    self.views.insert((handle, view_id), view);
 967                    if handled {
 968                        return true;
 969                    }
 970                } else {
 971                    log::error!("view {} does not exist", view_id)
 972                }
 973            }
 974        }
 975
 976        false
 977    }
 978
 979    pub(crate) fn dispatch_modifiers_changed(&mut self, event: &ModifiersChangedEvent) -> bool {
 980        let handle = self.window_handle;
 981        if let Some(focused_view_id) = self.window.focused_view_id {
 982            for view_id in self.ancestors(focused_view_id).collect::<Vec<_>>() {
 983                if let Some(mut view) = self.views.remove(&(handle, view_id)) {
 984                    let handled = view.modifiers_changed(event, self, view_id);
 985                    self.views.insert((handle, view_id), view);
 986                    if handled {
 987                        return true;
 988                    }
 989                } else {
 990                    log::error!("view {} does not exist", view_id)
 991                }
 992            }
 993        }
 994
 995        false
 996    }
 997
 998    pub fn invalidate(&mut self, mut invalidation: WindowInvalidation, appearance: Appearance) {
 999        self.start_frame();
1000        self.window.appearance = appearance;
1001        for view_id in &invalidation.removed {
1002            invalidation.updated.remove(view_id);
1003            self.window.rendered_views.remove(view_id);
1004        }
1005        for view_id in &invalidation.updated {
1006            let titlebar_height = self.window.titlebar_height;
1007            let element = self
1008                .render_view(RenderParams {
1009                    view_id: *view_id,
1010                    titlebar_height,
1011                    refreshing: false,
1012                    appearance,
1013                })
1014                .unwrap();
1015            self.window.rendered_views.insert(*view_id, element);
1016        }
1017    }
1018
1019    pub fn render_view(&mut self, params: RenderParams) -> Result<Box<dyn AnyRootElement>> {
1020        let handle = self.window_handle;
1021        let view_id = params.view_id;
1022        let mut view = self
1023            .views
1024            .remove(&(handle, view_id))
1025            .ok_or_else(|| anyhow!("view not found"))?;
1026        let element = view.render(self, view_id);
1027        self.views.insert((handle, view_id), view);
1028        Ok(element)
1029    }
1030
1031    pub fn layout(&mut self, refreshing: bool) -> Result<HashMap<usize, usize>> {
1032        let window_size = self.window.platform_window.content_size();
1033        let root_view_id = self.window.root_view().id();
1034
1035        let mut rendered_root = self.window.rendered_views.remove(&root_view_id).unwrap();
1036
1037        rendered_root.layout(SizeConstraint::strict(window_size), refreshing, self)?;
1038
1039        let views_to_notify_if_ancestors_change =
1040            mem::take(&mut self.window.views_to_notify_if_ancestors_change);
1041        for (view_id, view_ids_to_notify) in views_to_notify_if_ancestors_change {
1042            let mut current_view_id = view_id;
1043            loop {
1044                let old_parent_id = self.window.parents.get(&current_view_id);
1045                let new_parent_id = self.window.new_parents.get(&current_view_id);
1046                if old_parent_id.is_none() && new_parent_id.is_none() {
1047                    break;
1048                } else if old_parent_id == new_parent_id {
1049                    current_view_id = *old_parent_id.unwrap();
1050                } else {
1051                    let handle = self.window_handle;
1052                    for view_id_to_notify in view_ids_to_notify {
1053                        self.notify_view(handle, view_id_to_notify);
1054                    }
1055                    break;
1056                }
1057            }
1058        }
1059
1060        let new_parents = mem::take(&mut self.window.new_parents);
1061        let old_parents = mem::replace(&mut self.window.parents, new_parents);
1062        self.window
1063            .rendered_views
1064            .insert(root_view_id, rendered_root);
1065        Ok(old_parents)
1066    }
1067
1068    pub fn paint(&mut self) -> Result<Scene> {
1069        let window_size = self.window.platform_window.content_size();
1070        let scale_factor = self.window.platform_window.scale_factor();
1071
1072        let root_view_id = self.window.root_view().id();
1073        let mut rendered_root = self.window.rendered_views.remove(&root_view_id).unwrap();
1074
1075        let mut scene_builder = SceneBuilder::new(scale_factor);
1076        rendered_root.paint(
1077            &mut scene_builder,
1078            Vector2F::zero(),
1079            RectF::from_points(Vector2F::zero(), window_size),
1080            self,
1081        )?;
1082        self.window
1083            .rendered_views
1084            .insert(root_view_id, rendered_root);
1085
1086        self.window.text_layout_cache.finish_frame();
1087        let mut scene = scene_builder.build();
1088        self.window.cursor_regions = scene.cursor_regions();
1089        self.window.mouse_regions = scene.mouse_regions();
1090        self.window.event_handlers = scene.take_event_handlers();
1091
1092        if self.window_is_active() {
1093            if let Some(event) = self.window.last_mouse_moved_event.clone() {
1094                self.dispatch_event(event, true);
1095            }
1096        }
1097
1098        Ok(scene)
1099    }
1100
1101    pub fn root_element(&self) -> &Box<dyn AnyRootElement> {
1102        let view_id = self.window.root_view().id();
1103        self.window.rendered_views.get(&view_id).unwrap()
1104    }
1105
1106    pub fn rect_for_text_range(&self, range_utf16: Range<usize>) -> Option<RectF> {
1107        let focused_view_id = self.window.focused_view_id?;
1108        self.window
1109            .rendered_views
1110            .get(&focused_view_id)?
1111            .rect_for_text_range(range_utf16, self)
1112            .log_err()
1113            .flatten()
1114    }
1115
1116    pub fn set_window_title(&mut self, title: &str) {
1117        self.window.platform_window.set_title(title);
1118    }
1119
1120    pub fn set_window_edited(&mut self, edited: bool) {
1121        self.window.platform_window.set_edited(edited);
1122    }
1123
1124    pub fn is_topmost_window_for_position(&self, position: Vector2F) -> bool {
1125        self.window
1126            .platform_window
1127            .is_topmost_for_position(position)
1128    }
1129
1130    pub fn activate_window(&self) {
1131        self.window.platform_window.activate();
1132    }
1133
1134    pub fn window_is_active(&self) -> bool {
1135        self.window.is_active
1136    }
1137
1138    pub fn window_is_fullscreen(&self) -> bool {
1139        self.window.is_fullscreen
1140    }
1141
1142    pub(crate) fn dispatch_action(&mut self, view_id: Option<usize>, action: &dyn Action) -> bool {
1143        if let Some(view_id) = view_id {
1144            self.halt_action_dispatch = false;
1145            self.visit_dispatch_path(view_id, |view_id, capture_phase, cx| {
1146                cx.update_any_view(view_id, |view, cx| {
1147                    let type_id = view.as_any().type_id();
1148                    if let Some((name, mut handlers)) = cx
1149                        .actions_mut(capture_phase)
1150                        .get_mut(&type_id)
1151                        .and_then(|h| h.remove_entry(&action.id()))
1152                    {
1153                        for handler in handlers.iter_mut().rev() {
1154                            cx.halt_action_dispatch = true;
1155                            handler(view, action, cx, view_id);
1156                            if cx.halt_action_dispatch {
1157                                break;
1158                            }
1159                        }
1160                        cx.actions_mut(capture_phase)
1161                            .get_mut(&type_id)
1162                            .unwrap()
1163                            .insert(name, handlers);
1164                    }
1165                });
1166
1167                !cx.halt_action_dispatch
1168            });
1169        }
1170
1171        if !self.halt_action_dispatch {
1172            self.halt_action_dispatch = self.dispatch_global_action_any(action);
1173        }
1174
1175        self.pending_effects
1176            .push_back(Effect::ActionDispatchNotification {
1177                action_id: action.id(),
1178            });
1179        self.halt_action_dispatch
1180    }
1181
1182    /// Returns an iterator over all of the view ids from the passed view up to the root of the window
1183    /// Includes the passed view itself
1184    pub(crate) fn ancestors(&self, mut view_id: usize) -> impl Iterator<Item = usize> + '_ {
1185        std::iter::once(view_id)
1186            .into_iter()
1187            .chain(std::iter::from_fn(move || {
1188                if let Some(parent_id) = self.window.parents.get(&view_id) {
1189                    view_id = *parent_id;
1190                    Some(view_id)
1191                } else {
1192                    None
1193                }
1194            }))
1195    }
1196
1197    // Traverses the parent tree. Walks down the tree toward the passed
1198    // view calling visit with true. Then walks back up the tree calling visit with false.
1199    // If `visit` returns false this function will immediately return.
1200    fn visit_dispatch_path(
1201        &mut self,
1202        view_id: usize,
1203        mut visit: impl FnMut(usize, bool, &mut WindowContext) -> bool,
1204    ) {
1205        // List of view ids from the leaf to the root of the window
1206        let path = self.ancestors(view_id).collect::<Vec<_>>();
1207
1208        // Walk down from the root to the leaf calling visit with capture_phase = true
1209        for view_id in path.iter().rev() {
1210            if !visit(*view_id, true, self) {
1211                return;
1212            }
1213        }
1214
1215        // Walk up from the leaf to the root calling visit with capture_phase = false
1216        for view_id in path.iter() {
1217            if !visit(*view_id, false, self) {
1218                return;
1219            }
1220        }
1221    }
1222
1223    pub fn focused_view_id(&self) -> Option<usize> {
1224        self.window.focused_view_id
1225    }
1226
1227    pub fn focus(&mut self, view_id: Option<usize>) {
1228        self.app_context.focus(self.window_handle, view_id);
1229    }
1230
1231    pub fn window_bounds(&self) -> WindowBounds {
1232        self.window.platform_window.bounds()
1233    }
1234
1235    pub fn titlebar_height(&self) -> f32 {
1236        self.window.titlebar_height
1237    }
1238
1239    pub fn window_appearance(&self) -> Appearance {
1240        self.window.appearance
1241    }
1242
1243    pub fn window_display_uuid(&self) -> Option<Uuid> {
1244        self.window.platform_window.screen().display_uuid()
1245    }
1246
1247    pub fn show_character_palette(&self) {
1248        self.window.platform_window.show_character_palette();
1249    }
1250
1251    pub fn minimize_window(&self) {
1252        self.window.platform_window.minimize();
1253    }
1254
1255    pub fn zoom_window(&self) {
1256        self.window.platform_window.zoom();
1257    }
1258
1259    pub fn toggle_full_screen(&self) {
1260        self.window.platform_window.toggle_full_screen();
1261    }
1262
1263    pub fn prompt(
1264        &self,
1265        level: PromptLevel,
1266        msg: &str,
1267        answers: &[&str],
1268    ) -> oneshot::Receiver<usize> {
1269        self.window.platform_window.prompt(level, msg, answers)
1270    }
1271
1272    pub fn add_view<T, F>(&mut self, build_view: F) -> ViewHandle<T>
1273    where
1274        T: View,
1275        F: FnOnce(&mut ViewContext<T>) -> T,
1276    {
1277        self.add_option_view(|cx| Some(build_view(cx))).unwrap()
1278    }
1279
1280    pub fn add_option_view<T, F>(&mut self, build_view: F) -> Option<ViewHandle<T>>
1281    where
1282        T: View,
1283        F: FnOnce(&mut ViewContext<T>) -> Option<T>,
1284    {
1285        let handle = self.window_handle;
1286        let view_id = post_inc(&mut self.next_id);
1287        let mut cx = ViewContext::mutable(self, view_id);
1288        let handle = if let Some(view) = build_view(&mut cx) {
1289            let mut keymap_context = KeymapContext::default();
1290            view.update_keymap_context(&mut keymap_context, cx.app_context());
1291            self.views_metadata.insert(
1292                (handle, view_id),
1293                ViewMetadata {
1294                    type_id: TypeId::of::<T>(),
1295                    keymap_context,
1296                },
1297            );
1298            self.views.insert((handle, view_id), Box::new(view));
1299            self.window
1300                .invalidation
1301                .get_or_insert_with(Default::default)
1302                .updated
1303                .insert(view_id);
1304            Some(ViewHandle::new(handle, view_id, &self.ref_counts))
1305        } else {
1306            None
1307        };
1308        handle
1309    }
1310
1311    pub fn text_style(&self) -> TextStyle {
1312        self.window
1313            .text_style_stack
1314            .last()
1315            .cloned()
1316            .unwrap_or(TextStyle::default(&self.font_cache))
1317    }
1318
1319    pub fn push_text_style(&mut self, refinement: &TextStyleRefinement) -> Result<()> {
1320        let mut style = self.text_style();
1321        style.refine(refinement, self.font_cache())?;
1322        self.window.text_style_stack.push(style);
1323        Ok(())
1324    }
1325
1326    pub fn pop_text_style(&mut self) {
1327        self.window.text_style_stack.pop();
1328    }
1329
1330    pub fn theme<T: 'static>(&self) -> &T {
1331        self.window
1332            .theme_stack
1333            .iter()
1334            .rev()
1335            .find_map(|theme| theme.downcast_ref())
1336            .ok_or_else(|| anyhow!("no theme provided of type {}", type_name::<T>()))
1337            .unwrap()
1338    }
1339
1340    pub fn push_theme<T: 'static>(&mut self, theme: T) {
1341        self.window.theme_stack.push(Box::new(theme));
1342    }
1343
1344    pub fn pop_theme(&mut self) {
1345        self.window.theme_stack.pop();
1346    }
1347}
1348
1349#[derive(Default)]
1350pub struct LayoutEngine(Taffy);
1351pub use taffy::style::Style as LayoutStyle;
1352
1353impl LayoutEngine {
1354    pub fn new() -> Self {
1355        Default::default()
1356    }
1357
1358    pub fn add_node<C>(&mut self, style: LayoutStyle, children: C) -> Result<LayoutId>
1359    where
1360        C: IntoIterator<Item = LayoutId>,
1361    {
1362        let children = children.into_iter().collect::<Vec<_>>();
1363        if children.is_empty() {
1364            Ok(self.0.new_leaf(style)?)
1365        } else {
1366            Ok(self.0.new_with_children(style, &children)?)
1367        }
1368    }
1369
1370    pub fn add_measured_node<F>(&mut self, style: LayoutStyle, measure: F) -> Result<LayoutId>
1371    where
1372        F: Fn(MeasureParams) -> Size<f32> + Sync + Send + 'static,
1373    {
1374        Ok(self
1375            .0
1376            .new_leaf_with_measure(style, MeasureFunc::Boxed(Box::new(MeasureFn(measure))))?)
1377    }
1378
1379    pub fn compute_layout(&mut self, root: LayoutId, available_space: Vector2F) -> Result<()> {
1380        self.0.compute_layout(
1381            root,
1382            taffy::geometry::Size {
1383                width: available_space.x().into(),
1384                height: available_space.y().into(),
1385            },
1386        )?;
1387        Ok(())
1388    }
1389
1390    pub fn computed_layout(&mut self, node: LayoutId) -> Result<Layout> {
1391        Ok(Layout::from(self.0.layout(node)?))
1392    }
1393}
1394
1395pub struct MeasureFn<F>(F);
1396
1397impl<F: Send + Sync> Measurable for MeasureFn<F>
1398where
1399    F: Fn(MeasureParams) -> Size<f32>,
1400{
1401    fn measure(
1402        &self,
1403        known_dimensions: taffy::prelude::Size<Option<f32>>,
1404        available_space: taffy::prelude::Size<taffy::style::AvailableSpace>,
1405    ) -> taffy::prelude::Size<f32> {
1406        (self.0)(MeasureParams {
1407            known_dimensions: known_dimensions.into(),
1408            available_space: available_space.into(),
1409        })
1410        .into()
1411    }
1412}
1413
1414#[derive(Debug, Clone, Default)]
1415pub struct Layout {
1416    pub bounds: RectF,
1417    pub order: u32,
1418}
1419
1420pub struct MeasureParams {
1421    pub known_dimensions: Size<Option<f32>>,
1422    pub available_space: Size<AvailableSpace>,
1423}
1424
1425#[derive(Clone, Debug)]
1426pub enum AvailableSpace {
1427    /// The amount of space available is the specified number of pixels
1428    Pixels(f32),
1429    /// The amount of space available is indefinite and the node should be laid out under a min-content constraint
1430    MinContent,
1431    /// The amount of space available is indefinite and the node should be laid out under a max-content constraint
1432    MaxContent,
1433}
1434
1435impl Default for AvailableSpace {
1436    fn default() -> Self {
1437        Self::Pixels(0.)
1438    }
1439}
1440
1441impl From<taffy::prelude::AvailableSpace> for AvailableSpace {
1442    fn from(value: taffy::prelude::AvailableSpace) -> Self {
1443        match value {
1444            taffy::prelude::AvailableSpace::Definite(pixels) => Self::Pixels(pixels),
1445            taffy::prelude::AvailableSpace::MinContent => Self::MinContent,
1446            taffy::prelude::AvailableSpace::MaxContent => Self::MaxContent,
1447        }
1448    }
1449}
1450
1451impl From<&taffy::tree::Layout> for Layout {
1452    fn from(value: &taffy::tree::Layout) -> Self {
1453        Self {
1454            bounds: RectF::new(
1455                vec2f(value.location.x, value.location.y),
1456                vec2f(value.size.width, value.size.height),
1457            ),
1458            order: value.order,
1459        }
1460    }
1461}
1462
1463pub type LayoutId = taffy::prelude::NodeId;
1464
1465pub struct RenderParams {
1466    pub view_id: usize,
1467    pub titlebar_height: f32,
1468    pub refreshing: bool,
1469    pub appearance: Appearance,
1470}
1471
1472#[derive(Clone, Copy, Debug, Default, Eq, PartialEq)]
1473pub enum Axis {
1474    #[default]
1475    Horizontal,
1476    Vertical,
1477}
1478
1479impl Axis {
1480    pub fn invert(self) -> Self {
1481        match self {
1482            Self::Horizontal => Self::Vertical,
1483            Self::Vertical => Self::Horizontal,
1484        }
1485    }
1486
1487    pub fn component(&self, point: Vector2F) -> f32 {
1488        match self {
1489            Self::Horizontal => point.x(),
1490            Self::Vertical => point.y(),
1491        }
1492    }
1493}
1494
1495impl ToJson for Axis {
1496    fn to_json(&self) -> serde_json::Value {
1497        match self {
1498            Axis::Horizontal => json!("horizontal"),
1499            Axis::Vertical => json!("vertical"),
1500        }
1501    }
1502}
1503
1504impl StaticColumnCount for Axis {}
1505impl Bind for Axis {
1506    fn bind(&self, statement: &Statement, start_index: i32) -> anyhow::Result<i32> {
1507        match self {
1508            Axis::Horizontal => "Horizontal",
1509            Axis::Vertical => "Vertical",
1510        }
1511        .bind(statement, start_index)
1512    }
1513}
1514
1515impl Column for Axis {
1516    fn column(statement: &mut Statement, start_index: i32) -> anyhow::Result<(Self, i32)> {
1517        String::column(statement, start_index).and_then(|(axis_text, next_index)| {
1518            Ok((
1519                match axis_text.as_str() {
1520                    "Horizontal" => Axis::Horizontal,
1521                    "Vertical" => Axis::Vertical,
1522                    _ => bail!("Stored serialized item kind is incorrect"),
1523                },
1524                next_index,
1525            ))
1526        })
1527    }
1528}
1529
1530pub trait Vector2FExt {
1531    fn along(self, axis: Axis) -> f32;
1532}
1533
1534impl Vector2FExt for Vector2F {
1535    fn along(self, axis: Axis) -> f32 {
1536        match axis {
1537            Axis::Horizontal => self.x(),
1538            Axis::Vertical => self.y(),
1539        }
1540    }
1541}
1542
1543pub trait RectFExt {
1544    fn length_along(self, axis: Axis) -> f32;
1545}
1546
1547impl RectFExt for RectF {
1548    fn length_along(self, axis: Axis) -> f32 {
1549        match axis {
1550            Axis::Horizontal => self.width(),
1551            Axis::Vertical => self.height(),
1552        }
1553    }
1554}
1555
1556#[derive(Copy, Clone, Debug)]
1557pub struct SizeConstraint {
1558    pub min: Vector2F,
1559    pub max: Vector2F,
1560}
1561
1562impl SizeConstraint {
1563    pub fn new(min: Vector2F, max: Vector2F) -> Self {
1564        Self { min, max }
1565    }
1566
1567    pub fn strict(size: Vector2F) -> Self {
1568        Self {
1569            min: size,
1570            max: size,
1571        }
1572    }
1573    pub fn loose(max: Vector2F) -> Self {
1574        Self {
1575            min: Vector2F::zero(),
1576            max,
1577        }
1578    }
1579
1580    pub fn strict_along(axis: Axis, max: f32) -> Self {
1581        match axis {
1582            Axis::Horizontal => Self {
1583                min: vec2f(max, 0.0),
1584                max: vec2f(max, f32::INFINITY),
1585            },
1586            Axis::Vertical => Self {
1587                min: vec2f(0.0, max),
1588                max: vec2f(f32::INFINITY, max),
1589            },
1590        }
1591    }
1592
1593    pub fn max_along(&self, axis: Axis) -> f32 {
1594        match axis {
1595            Axis::Horizontal => self.max.x(),
1596            Axis::Vertical => self.max.y(),
1597        }
1598    }
1599
1600    pub fn min_along(&self, axis: Axis) -> f32 {
1601        match axis {
1602            Axis::Horizontal => self.min.x(),
1603            Axis::Vertical => self.min.y(),
1604        }
1605    }
1606
1607    pub fn constrain(&self, size: Vector2F) -> Vector2F {
1608        vec2f(
1609            size.x().min(self.max.x()).max(self.min.x()),
1610            size.y().min(self.max.y()).max(self.min.y()),
1611        )
1612    }
1613}
1614
1615impl Sub<Vector2F> for SizeConstraint {
1616    type Output = SizeConstraint;
1617
1618    fn sub(self, rhs: Vector2F) -> SizeConstraint {
1619        SizeConstraint {
1620            min: self.min - rhs,
1621            max: self.max - rhs,
1622        }
1623    }
1624}
1625
1626impl Default for SizeConstraint {
1627    fn default() -> Self {
1628        SizeConstraint {
1629            min: Vector2F::zero(),
1630            max: Vector2F::splat(f32::INFINITY),
1631        }
1632    }
1633}
1634
1635impl ToJson for SizeConstraint {
1636    fn to_json(&self) -> serde_json::Value {
1637        json!({
1638            "min": self.min.to_json(),
1639            "max": self.max.to_json(),
1640        })
1641    }
1642}
1643
1644#[derive(Clone)]
1645pub struct ChildView {
1646    view_id: usize,
1647    view_name: &'static str,
1648}
1649
1650impl ChildView {
1651    pub fn new(view: &AnyViewHandle, cx: &AppContext) -> Self {
1652        let view_name = cx.view_ui_name(view.window, view.id()).unwrap();
1653        Self {
1654            view_id: view.id(),
1655            view_name,
1656        }
1657    }
1658}
1659
1660impl<V: 'static> Element<V> for ChildView {
1661    type LayoutState = ();
1662    type PaintState = ();
1663
1664    fn layout(
1665        &mut self,
1666        constraint: SizeConstraint,
1667        _: &mut V,
1668        cx: &mut LayoutContext<V>,
1669    ) -> (Vector2F, Self::LayoutState) {
1670        if let Some(mut rendered_view) = cx.window.rendered_views.remove(&self.view_id) {
1671            let parent_id = cx.view_id();
1672            cx.window.new_parents.insert(self.view_id, parent_id);
1673            let size = rendered_view
1674                .layout(constraint, cx.refreshing, cx.view_context)
1675                .log_err()
1676                .unwrap_or(Vector2F::zero());
1677            cx.window.rendered_views.insert(self.view_id, rendered_view);
1678            (size, ())
1679        } else {
1680            log::error!(
1681                "layout called on a ChildView element whose underlying view was dropped (view_id: {}, name: {:?})",
1682                self.view_id,
1683                self.view_name
1684            );
1685            (Vector2F::zero(), ())
1686        }
1687    }
1688
1689    fn paint(
1690        &mut self,
1691        scene: &mut SceneBuilder,
1692        bounds: RectF,
1693        visible_bounds: RectF,
1694        _: &mut Self::LayoutState,
1695        _: &mut V,
1696        cx: &mut PaintContext<V>,
1697    ) {
1698        if let Some(mut rendered_view) = cx.window.rendered_views.remove(&self.view_id) {
1699            rendered_view
1700                .paint(scene, bounds.origin(), visible_bounds, cx)
1701                .log_err();
1702            cx.window.rendered_views.insert(self.view_id, rendered_view);
1703        } else {
1704            log::error!(
1705                "paint called on a ChildView element whose underlying view was dropped (view_id: {}, name: {:?})",
1706                self.view_id,
1707                self.view_name
1708            );
1709        }
1710    }
1711
1712    fn rect_for_text_range(
1713        &self,
1714        range_utf16: Range<usize>,
1715        _: RectF,
1716        _: RectF,
1717        _: &Self::LayoutState,
1718        _: &Self::PaintState,
1719        _: &V,
1720        cx: &ViewContext<V>,
1721    ) -> Option<RectF> {
1722        if let Some(rendered_view) = cx.window.rendered_views.get(&self.view_id) {
1723            rendered_view
1724                .rect_for_text_range(range_utf16, &cx.window_context)
1725                .log_err()
1726                .flatten()
1727        } else {
1728            log::error!(
1729                "rect_for_text_range called on a ChildView element whose underlying view was dropped (view_id: {}, name: {:?})",
1730                self.view_id,
1731                self.view_name
1732            );
1733            None
1734        }
1735    }
1736
1737    fn debug(
1738        &self,
1739        bounds: RectF,
1740        _: &Self::LayoutState,
1741        _: &Self::PaintState,
1742        _: &V,
1743        cx: &ViewContext<V>,
1744    ) -> serde_json::Value {
1745        json!({
1746            "type": "ChildView",
1747            "bounds": bounds.to_json(),
1748            "child": if let Some(element) = cx.window.rendered_views.get(&self.view_id) {
1749                element.debug(&cx.window_context).log_err().unwrap_or_else(|| json!(null))
1750            } else {
1751                json!(null)
1752            }
1753        })
1754    }
1755}