window.rs

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