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Diffstat (limited to 'components/layout/layout_thread.rs')
| -rw-r--r-- | components/layout/layout_thread.rs | 1368 |
1 files changed, 1368 insertions, 0 deletions
diff --git a/components/layout/layout_thread.rs b/components/layout/layout_thread.rs new file mode 100644 index 00000000000..668d08e2c85 --- /dev/null +++ b/components/layout/layout_thread.rs @@ -0,0 +1,1368 @@ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +//! The layout thread. Performs layout on the DOM, builds display lists and sends them to be +//! painted. + +#![allow(unsafe_code)] + +use animation; +use app_units::Au; +use azure::azure::AzColor; +use canvas_traits::CanvasMsg; +use construct::ConstructionResult; +use context::{SharedLayoutContext, heap_size_of_local_context}; +use display_list_builder::ToGfxColor; +use euclid::Matrix4; +use euclid::point::Point2D; +use euclid::rect::Rect; +use euclid::scale_factor::ScaleFactor; +use euclid::size::Size2D; +use flow::{self, Flow, ImmutableFlowUtils, MutableFlowUtils, MutableOwnedFlowUtils}; +use flow_ref::{self, FlowRef}; +use fnv::FnvHasher; +use gfx::display_list::{ClippingRegion, DisplayList, LayerInfo, OpaqueNode, StackingContext}; +use gfx::font; +use gfx::font_cache_thread::FontCacheThread; +use gfx::font_context; +use gfx::paint_thread::{LayoutToPaintMsg, PaintLayer}; +use gfx_traits::{color, LayerId, ScrollPolicy}; +use incremental::{LayoutDamageComputation, REFLOW, REFLOW_ENTIRE_DOCUMENT, REPAINT}; +use ipc_channel::ipc::{self, IpcReceiver, IpcSender}; +use ipc_channel::router::ROUTER; +use layout_debug; +use layout_traits::LayoutThreadFactory; +use log; +use msg::ParseErrorReporter; +use msg::compositor_msg::Epoch; +use msg::constellation_msg::{ConstellationChan, Failure, PipelineId}; +use net_traits::image_cache_thread::{ImageCacheChan, ImageCacheResult, ImageCacheThread}; +use parallel; +use profile_traits::mem::{self, Report, ReportKind, ReportsChan}; +use profile_traits::time::{TimerMetadataFrameType, TimerMetadataReflowType}; +use profile_traits::time::{self, TimerMetadata, profile}; +use query::{LayoutRPCImpl, process_content_box_request, process_content_boxes_request}; +use query::{process_node_geometry_request, process_offset_parent_query, process_resolved_style_request}; +use script::dom::node::OpaqueStyleAndLayoutData; +use script::layout_interface::Animation; +use script::layout_interface::{LayoutRPC, OffsetParentResponse}; +use script::layout_interface::{Msg, NewLayoutThreadInfo, Reflow, ReflowGoal, ReflowQueryType}; +use script::layout_interface::{ScriptLayoutChan, ScriptReflow}; +use script::reporter::CSSErrorReporter; +use script_traits::ConstellationControlMsg; +use script_traits::{LayoutControlMsg, LayoutMsg as ConstellationMsg, OpaqueScriptLayoutChannel}; +use sequential; +use serde_json; +use std::borrow::ToOwned; +use std::cell::RefCell; +use std::collections::HashMap; +use std::collections::hash_state::DefaultState; +use std::mem::transmute; +use std::ops::{Deref, DerefMut}; +use std::sync::atomic::{AtomicUsize, Ordering}; +use std::sync::mpsc::{channel, Sender, Receiver}; +use std::sync::{Arc, Mutex, MutexGuard, RwLock}; +use style::computed_values::{filter, mix_blend_mode}; +use style::context::{SharedStyleContext, StylistWrapper}; +use style::dom::{TDocument, TElement, TNode}; +use style::media_queries::{Device, MediaType}; +use style::parallel::WorkQueueData; +use style::selector_matching::{Stylist, USER_OR_USER_AGENT_STYLESHEETS}; +use style::stylesheets::{CSSRuleIteratorExt, Stylesheet}; +use traversal::RecalcStyleAndConstructFlows; +use url::Url; +use util::geometry::MAX_RECT; +use util::ipc::OptionalIpcSender; +use util::logical_geometry::LogicalPoint; +use util::mem::HeapSizeOf; +use util::opts; +use util::thread; +use util::thread_state; +use util::workqueue::WorkQueue; +use wrapper::{LayoutNode, NonOpaqueStyleAndLayoutData, ServoLayoutNode, ThreadSafeLayoutNode}; + +/// The number of screens of data we're allowed to generate display lists for in each direction. +pub const DISPLAY_PORT_SIZE_FACTOR: i32 = 8; + +/// The number of screens we have to traverse before we decide to generate new display lists. +const DISPLAY_PORT_THRESHOLD_SIZE_FACTOR: i32 = 4; + +/// Mutable data belonging to the LayoutThread. +/// +/// This needs to be protected by a mutex so we can do fast RPCs. +pub struct LayoutThreadData { + /// The channel on which messages can be sent to the constellation. + pub constellation_chan: ConstellationChan<ConstellationMsg>, + + /// The root stacking context. + pub stacking_context: Option<Arc<StackingContext>>, + + /// Performs CSS selector matching and style resolution. + pub stylist: Box<Stylist>, + + /// A queued response for the union of the content boxes of a node. + pub content_box_response: Rect<Au>, + + /// A queued response for the content boxes of a node. + pub content_boxes_response: Vec<Rect<Au>>, + + /// A queued response for the client {top, left, width, height} of a node in pixels. + pub client_rect_response: Rect<i32>, + + /// A queued response for the resolved style property of an element. + pub resolved_style_response: Option<String>, + + /// A queued response for the offset parent/rect of a node. + pub offset_parent_response: OffsetParentResponse, +} + +/// Information needed by the layout thread. +pub struct LayoutThread { + /// The ID of the pipeline that we belong to. + id: PipelineId, + + /// The URL of the pipeline that we belong to. + url: RefCell<Url>, + + /// Is the current reflow of an iframe, as opposed to a root window? + is_iframe: bool, + + /// The port on which we receive messages from the script thread. + port: Receiver<Msg>, + + /// The port on which we receive messages from the constellation. + pipeline_port: Receiver<LayoutControlMsg>, + + /// The port on which we receive messages from the image cache + image_cache_receiver: Receiver<ImageCacheResult>, + + /// The channel on which the image cache can send messages to ourself. + image_cache_sender: ImageCacheChan, + + /// The port on which we receive messages from the font cache thread. + font_cache_receiver: Receiver<()>, + + /// The channel on which the font cache can send messages to us. + font_cache_sender: IpcSender<()>, + + /// The channel on which messages can be sent to the constellation. + constellation_chan: ConstellationChan<ConstellationMsg>, + + /// The channel on which messages can be sent to the script thread. + script_chan: IpcSender<ConstellationControlMsg>, + + /// The channel on which messages can be sent to the painting thread. + paint_chan: OptionalIpcSender<LayoutToPaintMsg>, + + /// The channel on which messages can be sent to the time profiler. + time_profiler_chan: time::ProfilerChan, + + /// The channel on which messages can be sent to the memory profiler. + mem_profiler_chan: mem::ProfilerChan, + + /// The channel on which messages can be sent to the image cache. + image_cache_thread: ImageCacheThread, + + /// Public interface to the font cache thread. + font_cache_thread: FontCacheThread, + + /// Is this the first reflow in this LayoutThread? + first_reflow: bool, + + /// To receive a canvas renderer associated to a layer, this message is propagated + /// to the paint chan + canvas_layers_receiver: Receiver<(LayerId, IpcSender<CanvasMsg>)>, + canvas_layers_sender: Sender<(LayerId, IpcSender<CanvasMsg>)>, + + /// The workers that we use for parallel operation. + parallel_traversal: Option<WorkQueue<SharedLayoutContext, WorkQueueData>>, + + /// Starts at zero, and increased by one every time a layout completes. + /// This can be used to easily check for invalid stale data. + generation: u32, + + /// A channel on which new animations that have been triggered by style recalculation can be + /// sent. + new_animations_sender: Sender<Animation>, + + /// Receives newly-discovered animations. + new_animations_receiver: Receiver<Animation>, + + /// The number of Web fonts that have been requested but not yet loaded. + outstanding_web_fonts: Arc<AtomicUsize>, + + /// The root of the flow tree. + root_flow: Option<FlowRef>, + + /// The position and size of the visible rect for each layer. We do not build display lists + /// for any areas more than `DISPLAY_PORT_SIZE_FACTOR` screens away from this area. + visible_rects: Arc<HashMap<LayerId, Rect<Au>, DefaultState<FnvHasher>>>, + + /// The list of currently-running animations. + running_animations: Arc<RwLock<HashMap<OpaqueNode, Vec<Animation>>>>, + + /// The list of animations that have expired since the last style recalculation. + expired_animations: Arc<RwLock<HashMap<OpaqueNode, Vec<Animation>>>>, + + /// A counter for epoch messages + epoch: Epoch, + + /// The size of the viewport. This may be different from the size of the screen due to viewport + /// constraints. + viewport_size: Size2D<Au>, + + /// A mutex to allow for fast, read-only RPC of layout's internal data + /// structures, while still letting the LayoutThread modify them. + /// + /// All the other elements of this struct are read-only. + rw_data: Arc<Mutex<LayoutThreadData>>, + + /// The CSS error reporter for all CSS loaded in this layout thread + error_reporter: CSSErrorReporter, + +} + +impl LayoutThreadFactory for LayoutThread { + /// Spawns a new layout thread. + fn create(_phantom: Option<&mut LayoutThread>, + id: PipelineId, + url: Url, + is_iframe: bool, + chan: OpaqueScriptLayoutChannel, + pipeline_port: IpcReceiver<LayoutControlMsg>, + constellation_chan: ConstellationChan<ConstellationMsg>, + failure_msg: Failure, + script_chan: IpcSender<ConstellationControlMsg>, + paint_chan: OptionalIpcSender<LayoutToPaintMsg>, + image_cache_thread: ImageCacheThread, + font_cache_thread: FontCacheThread, + time_profiler_chan: time::ProfilerChan, + mem_profiler_chan: mem::ProfilerChan, + shutdown_chan: IpcSender<()>, + content_process_shutdown_chan: IpcSender<()>) { + let ConstellationChan(con_chan) = constellation_chan.clone(); + thread::spawn_named_with_send_on_failure(format!("LayoutThread {:?}", id), + thread_state::LAYOUT, + move || { + { // Ensures layout thread is destroyed before we send shutdown message + let sender = chan.sender(); + let layout = LayoutThread::new(id, + url, + is_iframe, + chan.receiver(), + pipeline_port, + constellation_chan, + script_chan, + paint_chan, + image_cache_thread, + font_cache_thread, + time_profiler_chan, + mem_profiler_chan.clone()); + + let reporter_name = format!("layout-reporter-{}", id); + mem_profiler_chan.run_with_memory_reporting(|| { + layout.start(); + }, reporter_name, sender, Msg::CollectReports); + } + let _ = shutdown_chan.send(()); + let _ = content_process_shutdown_chan.send(()); + }, ConstellationMsg::Failure(failure_msg), con_chan); + } +} + +/// The `LayoutThread` `rw_data` lock must remain locked until the first reflow, +/// as RPC calls don't make sense until then. Use this in combination with +/// `LayoutThread::lock_rw_data` and `LayoutThread::return_rw_data`. +pub enum RWGuard<'a> { + /// If the lock was previously held, from when the thread started. + Held(MutexGuard<'a, LayoutThreadData>), + /// If the lock was just used, and has been returned since there has been + /// a reflow already. + Used(MutexGuard<'a, LayoutThreadData>), +} + +impl<'a> Deref for RWGuard<'a> { + type Target = LayoutThreadData; + fn deref(&self) -> &LayoutThreadData { + match *self { + RWGuard::Held(ref x) => &**x, + RWGuard::Used(ref x) => &**x, + } + } +} + +impl<'a> DerefMut for RWGuard<'a> { + fn deref_mut(&mut self) -> &mut LayoutThreadData { + match *self { + RWGuard::Held(ref mut x) => &mut **x, + RWGuard::Used(ref mut x) => &mut **x, + } + } +} + +struct RwData<'a, 'b: 'a> { + rw_data: &'b Arc<Mutex<LayoutThreadData>>, + possibly_locked_rw_data: &'a mut Option<MutexGuard<'b, LayoutThreadData>>, +} + +impl<'a, 'b: 'a> RwData<'a, 'b> { + /// If no reflow has happened yet, this will just return the lock in + /// `possibly_locked_rw_data`. Otherwise, it will acquire the `rw_data` lock. + /// + /// If you do not wish RPCs to remain blocked, just drop the `RWGuard` + /// returned from this function. If you _do_ wish for them to remain blocked, + /// use `block`. + fn lock(&mut self) -> RWGuard<'b> { + match self.possibly_locked_rw_data.take() { + None => RWGuard::Used(self.rw_data.lock().unwrap()), + Some(x) => RWGuard::Held(x), + } + } + + /// If no reflow has ever been triggered, this will keep the lock, locked + /// (and saved in `possibly_locked_rw_data`). If it has been, the lock will + /// be unlocked. + fn block(&mut self, rw_data: RWGuard<'b>) { + match rw_data { + RWGuard::Used(x) => drop(x), + RWGuard::Held(x) => *self.possibly_locked_rw_data = Some(x), + } + } +} + +fn add_font_face_rules(stylesheet: &Stylesheet, + device: &Device, + font_cache_thread: &FontCacheThread, + font_cache_sender: &IpcSender<()>, + outstanding_web_fonts_counter: &Arc<AtomicUsize>) { + for font_face in stylesheet.effective_rules(&device).font_face() { + for source in &font_face.sources { + if opts::get().load_webfonts_synchronously { + let (sender, receiver) = ipc::channel().unwrap(); + font_cache_thread.add_web_font(font_face.family.clone(), + (*source).clone(), + sender); + receiver.recv().unwrap(); + } else { + outstanding_web_fonts_counter.fetch_add(1, Ordering::SeqCst); + font_cache_thread.add_web_font(font_face.family.clone(), + (*source).clone(), + (*font_cache_sender).clone()); + } + } + } +} + +impl LayoutThread { + /// Creates a new `LayoutThread` structure. + fn new(id: PipelineId, + url: Url, + is_iframe: bool, + port: Receiver<Msg>, + pipeline_port: IpcReceiver<LayoutControlMsg>, + constellation_chan: ConstellationChan<ConstellationMsg>, + script_chan: IpcSender<ConstellationControlMsg>, + paint_chan: OptionalIpcSender<LayoutToPaintMsg>, + image_cache_thread: ImageCacheThread, + font_cache_thread: FontCacheThread, + time_profiler_chan: time::ProfilerChan, + mem_profiler_chan: mem::ProfilerChan) + -> LayoutThread { + let device = Device::new( + MediaType::Screen, + opts::get().initial_window_size.as_f32() * ScaleFactor::new(1.0)); + let parallel_traversal = if opts::get().layout_threads != 1 { + Some(WorkQueue::new("LayoutWorker", thread_state::LAYOUT, + opts::get().layout_threads)) + } else { + None + }; + + // Create the channel on which new animations can be sent. + let (new_animations_sender, new_animations_receiver) = channel(); + let (canvas_layers_sender, canvas_layers_receiver) = channel(); + + // Proxy IPC messages from the pipeline to the layout thread. + let pipeline_receiver = ROUTER.route_ipc_receiver_to_new_mpsc_receiver(pipeline_port); + + // Ask the router to proxy IPC messages from the image cache thread to the layout thread. + let (ipc_image_cache_sender, ipc_image_cache_receiver) = ipc::channel().unwrap(); + let image_cache_receiver = + ROUTER.route_ipc_receiver_to_new_mpsc_receiver(ipc_image_cache_receiver); + + // Ask the router to proxy IPC messages from the font cache thread to the layout thread. + let (ipc_font_cache_sender, ipc_font_cache_receiver) = ipc::channel().unwrap(); + let font_cache_receiver = + ROUTER.route_ipc_receiver_to_new_mpsc_receiver(ipc_font_cache_receiver); + + let stylist = box Stylist::new(device); + let outstanding_web_fonts_counter = Arc::new(AtomicUsize::new(0)); + for stylesheet in &*USER_OR_USER_AGENT_STYLESHEETS { + add_font_face_rules(stylesheet, + &stylist.device, + &font_cache_thread, + &ipc_font_cache_sender, + &outstanding_web_fonts_counter); + } + + LayoutThread { + id: id, + url: RefCell::new(url), + is_iframe: is_iframe, + port: port, + pipeline_port: pipeline_receiver, + script_chan: script_chan, + constellation_chan: constellation_chan.clone(), + paint_chan: paint_chan, + time_profiler_chan: time_profiler_chan, + mem_profiler_chan: mem_profiler_chan, + image_cache_thread: image_cache_thread, + font_cache_thread: font_cache_thread, + first_reflow: true, + image_cache_receiver: image_cache_receiver, + image_cache_sender: ImageCacheChan(ipc_image_cache_sender), + font_cache_receiver: font_cache_receiver, + font_cache_sender: ipc_font_cache_sender, + canvas_layers_receiver: canvas_layers_receiver, + canvas_layers_sender: canvas_layers_sender, + parallel_traversal: parallel_traversal, + generation: 0, + new_animations_sender: new_animations_sender, + new_animations_receiver: new_animations_receiver, + outstanding_web_fonts: outstanding_web_fonts_counter, + root_flow: None, + visible_rects: Arc::new(HashMap::with_hash_state(Default::default())), + running_animations: Arc::new(RwLock::new(HashMap::new())), + expired_animations: Arc::new(RwLock::new(HashMap::new())), + epoch: Epoch(0), + viewport_size: Size2D::new(Au(0), Au(0)), + rw_data: Arc::new(Mutex::new( + LayoutThreadData { + constellation_chan: constellation_chan, + stacking_context: None, + stylist: stylist, + content_box_response: Rect::zero(), + content_boxes_response: Vec::new(), + client_rect_response: Rect::zero(), + resolved_style_response: None, + offset_parent_response: OffsetParentResponse::empty(), + })), + error_reporter: CSSErrorReporter { pipelineid: id }, + } + } + + /// Starts listening on the port. + fn start(mut self) { + let rw_data = self.rw_data.clone(); + let mut possibly_locked_rw_data = Some(rw_data.lock().unwrap()); + let mut rw_data = RwData { + rw_data: &rw_data, + possibly_locked_rw_data: &mut possibly_locked_rw_data, + }; + while self.handle_request(&mut rw_data) { + // Loop indefinitely. + } + } + + // Create a layout context for use in building display lists, hit testing, &c. + fn build_shared_layout_context(&self, + rw_data: &LayoutThreadData, + screen_size_changed: bool, + url: &Url, + goal: ReflowGoal) + -> SharedLayoutContext { + SharedLayoutContext { + style_context: SharedStyleContext { + viewport_size: self.viewport_size.clone(), + screen_size_changed: screen_size_changed, + stylist: StylistWrapper(&*rw_data.stylist), + generation: self.generation, + goal: goal, + new_animations_sender: Mutex::new(self.new_animations_sender.clone()), + running_animations: self.running_animations.clone(), + expired_animations: self.expired_animations.clone(), + error_reporter: self.error_reporter.clone(), + }, + image_cache_thread: self.image_cache_thread.clone(), + image_cache_sender: Mutex::new(self.image_cache_sender.clone()), + font_cache_thread: Mutex::new(self.font_cache_thread.clone()), + canvas_layers_sender: Mutex::new(self.canvas_layers_sender.clone()), + url: (*url).clone(), + visible_rects: self.visible_rects.clone(), + } + } + + /// Receives and dispatches messages from the script and constellation threads + fn handle_request<'a, 'b>(&mut self, possibly_locked_rw_data: &mut RwData<'a, 'b>) -> bool { + enum Request { + FromPipeline(LayoutControlMsg), + FromScript(Msg), + FromImageCache, + FromFontCache, + } + + let request = { + let port_from_script = &self.port; + let port_from_pipeline = &self.pipeline_port; + let port_from_image_cache = &self.image_cache_receiver; + let port_from_font_cache = &self.font_cache_receiver; + select! { + msg = port_from_pipeline.recv() => { + Request::FromPipeline(msg.unwrap()) + }, + msg = port_from_script.recv() => { + Request::FromScript(msg.unwrap()) + }, + msg = port_from_image_cache.recv() => { + msg.unwrap(); + Request::FromImageCache + }, + msg = port_from_font_cache.recv() => { + msg.unwrap(); + Request::FromFontCache + } + } + }; + + match request { + Request::FromPipeline(LayoutControlMsg::SetVisibleRects(new_visible_rects)) => { + self.handle_request_helper(Msg::SetVisibleRects(new_visible_rects), + possibly_locked_rw_data) + }, + Request::FromPipeline(LayoutControlMsg::TickAnimations) => { + self.handle_request_helper(Msg::TickAnimations, possibly_locked_rw_data) + }, + Request::FromPipeline(LayoutControlMsg::GetCurrentEpoch(sender)) => { + self.handle_request_helper(Msg::GetCurrentEpoch(sender), possibly_locked_rw_data) + }, + Request::FromPipeline(LayoutControlMsg::GetWebFontLoadState(sender)) => { + self.handle_request_helper(Msg::GetWebFontLoadState(sender), + possibly_locked_rw_data) + }, + Request::FromPipeline(LayoutControlMsg::ExitNow) => { + self.handle_request_helper(Msg::ExitNow, possibly_locked_rw_data) + }, + Request::FromScript(msg) => { + self.handle_request_helper(msg, possibly_locked_rw_data) + }, + Request::FromImageCache => { + self.repaint(possibly_locked_rw_data) + }, + Request::FromFontCache => { + let _rw_data = possibly_locked_rw_data.lock(); + self.outstanding_web_fonts.fetch_sub(1, Ordering::SeqCst); + font_context::invalidate_font_caches(); + self.script_chan.send(ConstellationControlMsg::WebFontLoaded(self.id)).unwrap(); + true + }, + } + } + + /// Repaint the scene, without performing style matching. This is typically + /// used when an image arrives asynchronously and triggers a relayout and + /// repaint. + /// TODO: In the future we could detect if the image size hasn't changed + /// since last time and avoid performing a complete layout pass. + fn repaint<'a, 'b>(&mut self, possibly_locked_rw_data: &mut RwData<'a, 'b>) -> bool { + let mut rw_data = possibly_locked_rw_data.lock(); + + let reflow_info = Reflow { + goal: ReflowGoal::ForDisplay, + page_clip_rect: MAX_RECT, + }; + let mut layout_context = self.build_shared_layout_context(&*rw_data, + false, + &self.url.borrow(), + reflow_info.goal); + + self.perform_post_style_recalc_layout_passes(&reflow_info, + &mut *rw_data, + &mut layout_context); + + + true + } + + /// Receives and dispatches messages from other threads. + fn handle_request_helper<'a, 'b>(&mut self, + request: Msg, + possibly_locked_rw_data: &mut RwData<'a, 'b>) + -> bool { + match request { + Msg::AddStylesheet(style_info) => { + self.handle_add_stylesheet(style_info, possibly_locked_rw_data) + } + Msg::SetQuirksMode => self.handle_set_quirks_mode(possibly_locked_rw_data), + Msg::GetRPC(response_chan) => { + response_chan.send(box LayoutRPCImpl(self.rw_data.clone()) as + Box<LayoutRPC + Send>).unwrap(); + }, + Msg::Reflow(data) => { + profile(time::ProfilerCategory::LayoutPerform, + self.profiler_metadata(), + self.time_profiler_chan.clone(), + || self.handle_reflow(&data, possibly_locked_rw_data)); + }, + Msg::TickAnimations => self.tick_all_animations(possibly_locked_rw_data), + Msg::ReflowWithNewlyLoadedWebFont => { + self.reflow_with_newly_loaded_web_font(possibly_locked_rw_data) + } + Msg::SetVisibleRects(new_visible_rects) => { + self.set_visible_rects(new_visible_rects, possibly_locked_rw_data); + } + Msg::ReapStyleAndLayoutData(dead_data) => { + unsafe { + self.handle_reap_style_and_layout_data(dead_data) + } + } + Msg::CollectReports(reports_chan) => { + self.collect_reports(reports_chan, possibly_locked_rw_data); + }, + Msg::GetCurrentEpoch(sender) => { + let _rw_data = possibly_locked_rw_data.lock(); + sender.send(self.epoch).unwrap(); + }, + Msg::GetWebFontLoadState(sender) => { + let _rw_data = possibly_locked_rw_data.lock(); + let outstanding_web_fonts = self.outstanding_web_fonts.load(Ordering::SeqCst); + sender.send(outstanding_web_fonts != 0).unwrap(); + }, + Msg::CreateLayoutThread(info) => { + self.create_layout_thread(info) + } + Msg::SetFinalUrl(final_url) => { + *self.url.borrow_mut() = final_url; + }, + Msg::PrepareToExit(response_chan) => { + self.prepare_to_exit(response_chan); + return false + }, + Msg::ExitNow => { + debug!("layout: ExitNow received"); + self.exit_now(); + return false + } + } + + true + } + + fn collect_reports<'a, 'b>(&self, + reports_chan: ReportsChan, + possibly_locked_rw_data: &mut RwData<'a, 'b>) { + let mut reports = vec![]; + + // FIXME(njn): Just measuring the display tree for now. + let rw_data = possibly_locked_rw_data.lock(); + let stacking_context = rw_data.stacking_context.as_ref(); + let formatted_url = &format!("url({})", *self.url.borrow()); + reports.push(Report { + path: path![formatted_url, "layout-thread", "display-list"], + kind: ReportKind::ExplicitJemallocHeapSize, + size: stacking_context.map_or(0, |sc| sc.heap_size_of_children()), + }); + + // The LayoutThread has a context in TLS... + reports.push(Report { + path: path![formatted_url, "layout-thread", "local-context"], + kind: ReportKind::ExplicitJemallocHeapSize, + size: heap_size_of_local_context(), + }); + + // ... as do each of the LayoutWorkers, if present. + if let Some(ref traversal) = self.parallel_traversal { + let sizes = traversal.heap_size_of_tls(heap_size_of_local_context); + for (i, size) in sizes.iter().enumerate() { + reports.push(Report { + path: path![formatted_url, + format!("layout-worker-{}-local-context", i)], + kind: ReportKind::ExplicitJemallocHeapSize, + size: *size, + }); + } + } + + reports_chan.send(reports); + } + + fn create_layout_thread(&self, info: NewLayoutThreadInfo) { + LayoutThreadFactory::create(None::<&mut LayoutThread>, + info.id, + info.url.clone(), + info.is_parent, + info.layout_pair, + info.pipeline_port, + info.constellation_chan, + info.failure, + info.script_chan.clone(), + info.paint_chan.to::<LayoutToPaintMsg>(), + self.image_cache_thread.clone(), + self.font_cache_thread.clone(), + self.time_profiler_chan.clone(), + self.mem_profiler_chan.clone(), + info.layout_shutdown_chan, + info.content_process_shutdown_chan); + } + + /// Enters a quiescent state in which no new messages will be processed until an `ExitNow` is + /// received. A pong is immediately sent on the given response channel. + fn prepare_to_exit(&mut self, response_chan: Sender<()>) { + response_chan.send(()).unwrap(); + loop { + match self.port.recv().unwrap() { + Msg::ReapStyleAndLayoutData(dead_data) => { + unsafe { + self.handle_reap_style_and_layout_data(dead_data) + } + } + Msg::ExitNow => { + debug!("layout thread is exiting..."); + self.exit_now(); + break + } + Msg::CollectReports(_) => { + // Just ignore these messages at this point. + } + _ => { + panic!("layout: unexpected message received after `PrepareToExitMsg`") + } + } + } + } + + /// Shuts down the layout thread now. If there are any DOM nodes left, layout will now (safely) + /// crash. + fn exit_now(&mut self) { + if let Some(ref mut traversal) = self.parallel_traversal { + traversal.shutdown() + } + + let (response_chan, response_port) = ipc::channel().unwrap(); + self.paint_chan.send(LayoutToPaintMsg::Exit(response_chan)).unwrap(); + response_port.recv().unwrap() + } + + fn handle_add_stylesheet<'a, 'b>(&self, + stylesheet: Arc<Stylesheet>, + possibly_locked_rw_data: &mut RwData<'a, 'b>) { + // Find all font-face rules and notify the font cache of them. + // GWTODO: Need to handle unloading web fonts. + + let rw_data = possibly_locked_rw_data.lock(); + if stylesheet.is_effective_for_device(&rw_data.stylist.device) { + add_font_face_rules(&*stylesheet, + &rw_data.stylist.device, + &self.font_cache_thread, + &self.font_cache_sender, + &self.outstanding_web_fonts); + } + + possibly_locked_rw_data.block(rw_data); + } + + /// Sets quirks mode for the document, causing the quirks mode stylesheet to be used. + fn handle_set_quirks_mode<'a, 'b>(&self, possibly_locked_rw_data: &mut RwData<'a, 'b>) { + let mut rw_data = possibly_locked_rw_data.lock(); + rw_data.stylist.set_quirks_mode(true); + possibly_locked_rw_data.block(rw_data); + } + + fn try_get_layout_root<'ln, N: LayoutNode<'ln>>(&self, node: N) -> Option<FlowRef> { + let mut data = match node.mutate_layout_data() { + Some(x) => x, + None => return None, + }; + let result = data.flow_construction_result.swap_out(); + + let mut flow = match result { + ConstructionResult::Flow(mut flow, abs_descendants) => { + // Note: Assuming that the root has display 'static' (as per + // CSS Section 9.3.1). Otherwise, if it were absolutely + // positioned, it would return a reference to itself in + // `abs_descendants` and would lead to a circular reference. + // Set Root as CB for any remaining absolute descendants. + flow.set_absolute_descendants(abs_descendants); + flow + } + _ => return None, + }; + + flow_ref::deref_mut(&mut flow).mark_as_root(); + + Some(flow) + } + + /// Performs layout constraint solving. + /// + /// This corresponds to `Reflow()` in Gecko and `layout()` in WebKit/Blink and should be + /// benchmarked against those two. It is marked `#[inline(never)]` to aid profiling. + #[inline(never)] + fn solve_constraints(layout_root: &mut FlowRef, + shared_layout_context: &SharedLayoutContext) { + let _scope = layout_debug_scope!("solve_constraints"); + sequential::traverse_flow_tree_preorder(layout_root, shared_layout_context); + } + + /// Performs layout constraint solving in parallel. + /// + /// This corresponds to `Reflow()` in Gecko and `layout()` in WebKit/Blink and should be + /// benchmarked against those two. It is marked `#[inline(never)]` to aid profiling. + #[inline(never)] + fn solve_constraints_parallel(traversal: &mut WorkQueue<SharedLayoutContext, WorkQueueData>, + layout_root: &mut FlowRef, + profiler_metadata: Option<TimerMetadata>, + time_profiler_chan: time::ProfilerChan, + shared_layout_context: &SharedLayoutContext) { + let _scope = layout_debug_scope!("solve_constraints_parallel"); + + // NOTE: this currently computes borders, so any pruning should separate that + // operation out. + parallel::traverse_flow_tree_preorder(layout_root, + profiler_metadata, + time_profiler_chan, + shared_layout_context, + traversal); + } + + fn compute_abs_pos_and_build_display_list(&mut self, + data: &Reflow, + layout_root: &mut FlowRef, + shared_layout_context: &mut SharedLayoutContext, + rw_data: &mut LayoutThreadData) { + let writing_mode = flow::base(&**layout_root).writing_mode; + let (metadata, sender) = (self.profiler_metadata(), self.time_profiler_chan.clone()); + profile(time::ProfilerCategory::LayoutDispListBuild, + metadata.clone(), + sender.clone(), + || { + flow::mut_base(flow_ref::deref_mut(layout_root)).stacking_relative_position = + LogicalPoint::zero(writing_mode).to_physical(writing_mode, + self.viewport_size); + + flow::mut_base(flow_ref::deref_mut(layout_root)).clip = + ClippingRegion::from_rect(&data.page_clip_rect); + + match (&mut self.parallel_traversal, opts::get().parallel_display_list_building) { + (&mut Some(ref mut traversal), true) => { + parallel::build_display_list_for_subtree(layout_root, + metadata, + sender, + shared_layout_context, + traversal); + } + _ => { + sequential::build_display_list_for_subtree(layout_root, + shared_layout_context); + } + } + + if data.goal == ReflowGoal::ForDisplay { + debug!("Done building display list."); + + let root_background_color = get_root_flow_background_color( + flow_ref::deref_mut(layout_root)); + let root_size = { + let root_flow = flow::base(&**layout_root); + if rw_data.stylist.viewport_constraints().is_some() { + root_flow.position.size.to_physical(root_flow.writing_mode) + } else { + root_flow.overflow.size + } + }; + let mut display_list = box DisplayList::new(); + display_list.append_from(&mut flow::mut_base(flow_ref::deref_mut(layout_root)) + .display_list_building_result); + + let origin = Rect::new(Point2D::new(Au(0), Au(0)), root_size); + let stacking_context = Arc::new(StackingContext::new(display_list, + &origin, + &origin, + 0, + filter::T::new(Vec::new()), + mix_blend_mode::T::normal, + Matrix4::identity(), + Matrix4::identity(), + true, + false, + None)); + if opts::get().dump_display_list { + stacking_context.print("DisplayList".to_owned()); + } + if opts::get().dump_display_list_json { + println!("{}", serde_json::to_string_pretty(&stacking_context).unwrap()); + } + + rw_data.stacking_context = Some(stacking_context.clone()); + + let layer_info = LayerInfo::new(layout_root.layer_id(), + ScrollPolicy::Scrollable, + None); + let paint_layer = PaintLayer::new_with_stacking_context(layer_info, + stacking_context, + root_background_color); + + debug!("Layout done!"); + + self.epoch.next(); + self.paint_chan + .send(LayoutToPaintMsg::PaintInit(self.epoch, paint_layer)) + .unwrap(); + } + }); + } + + /// The high-level routine that performs layout threads. + fn handle_reflow<'a, 'b>(&mut self, + data: &ScriptReflow, + possibly_locked_rw_data: &mut RwData<'a, 'b>) { + let document = unsafe { ServoLayoutNode::new(&data.document) }; + let document = document.as_document().unwrap(); + + debug!("layout: received layout request for: {}", self.url.borrow().serialize()); + + let mut rw_data = possibly_locked_rw_data.lock(); + + let node: ServoLayoutNode = match document.root_node() { + None => { + // Since we cannot compute anything, give spec-required placeholders. + debug!("layout: No root node: bailing"); + match data.query_type { + ReflowQueryType::ContentBoxQuery(_) => { + rw_data.content_box_response = Rect::zero(); + }, + ReflowQueryType::ContentBoxesQuery(_) => { + rw_data.content_boxes_response = Vec::new(); + }, + ReflowQueryType::NodeGeometryQuery(_) => { + rw_data.client_rect_response = Rect::zero(); + }, + ReflowQueryType::ResolvedStyleQuery(_, _, _) => { + rw_data.resolved_style_response = None; + }, + ReflowQueryType::OffsetParentQuery(_) => { + rw_data.offset_parent_response = OffsetParentResponse::empty(); + }, + ReflowQueryType::NoQuery => {} + } + return; + }, + Some(x) => x, + }; + + debug!("layout: received layout request for: {}", + self.url.borrow().serialize()); + if log_enabled!(log::LogLevel::Debug) { + node.dump(); + } + + let initial_viewport = data.window_size.initial_viewport; + let old_viewport_size = self.viewport_size; + let current_screen_size = Size2D::new(Au::from_f32_px(initial_viewport.width.get()), + Au::from_f32_px(initial_viewport.height.get())); + + // Calculate the actual viewport as per DEVICE-ADAPT § 6 + let device = Device::new(MediaType::Screen, initial_viewport); + rw_data.stylist.set_device(device, &data.document_stylesheets); + + let constraints = rw_data.stylist.viewport_constraints().clone(); + self.viewport_size = match constraints { + Some(ref constraints) => { + debug!("Viewport constraints: {:?}", constraints); + + // other rules are evaluated against the actual viewport + Size2D::new(Au::from_f32_px(constraints.size.width.get()), + Au::from_f32_px(constraints.size.height.get())) + } + None => current_screen_size, + }; + + // Handle conditions where the entire flow tree is invalid. + let viewport_size_changed = self.viewport_size != old_viewport_size; + if viewport_size_changed { + if let Some(constraints) = constraints { + // let the constellation know about the viewport constraints + let ConstellationChan(ref constellation_chan) = rw_data.constellation_chan; + constellation_chan.send(ConstellationMsg::ViewportConstrained( + self.id, constraints)).unwrap(); + } + } + + // If the entire flow tree is invalid, then it will be reflowed anyhow. + let needs_dirtying = rw_data.stylist.update(&data.document_stylesheets, + data.stylesheets_changed); + let needs_reflow = viewport_size_changed && !needs_dirtying; + unsafe { + if needs_dirtying { + LayoutThread::dirty_all_nodes(node); + } + } + if needs_reflow { + if let Some(mut flow) = self.try_get_layout_root(node) { + LayoutThread::reflow_all_nodes(flow_ref::deref_mut(&mut flow)); + } + } + + let modified_elements = document.drain_modified_elements(); + if !needs_dirtying { + for (el, snapshot) in modified_elements { + let hint = rw_data.stylist.compute_restyle_hint(&el, &snapshot, el.get_state()); + el.note_restyle_hint(hint); + } + } + + // Create a layout context for use throughout the following passes. + let mut shared_layout_context = self.build_shared_layout_context(&*rw_data, + viewport_size_changed, + &self.url.borrow(), + data.reflow_info.goal); + + if node.is_dirty() || node.has_dirty_descendants() { + // Recalculate CSS styles and rebuild flows and fragments. + profile(time::ProfilerCategory::LayoutStyleRecalc, + self.profiler_metadata(), + self.time_profiler_chan.clone(), + || { + // Perform CSS selector matching and flow construction. + match self.parallel_traversal { + None => { + sequential::traverse_dom::<ServoLayoutNode, RecalcStyleAndConstructFlows>( + node, &shared_layout_context); + } + Some(ref mut traversal) => { + parallel::traverse_dom::<ServoLayoutNode, RecalcStyleAndConstructFlows>( + node, &shared_layout_context, traversal); + } + } + }); + + // TODO(pcwalton): Measure energy usage of text shaping, perhaps? + let text_shaping_time = + (font::get_and_reset_text_shaping_performance_counter() as u64) / + (opts::get().layout_threads as u64); + time::send_profile_data(time::ProfilerCategory::LayoutTextShaping, + self.profiler_metadata(), + self.time_profiler_chan.clone(), + 0, + text_shaping_time, + 0, + 0); + + // Retrieve the (possibly rebuilt) root flow. + self.root_flow = self.try_get_layout_root(node); + } + + // Send new canvas renderers to the paint thread + while let Ok((layer_id, renderer)) = self.canvas_layers_receiver.try_recv() { + // Just send if there's an actual renderer + self.paint_chan.send(LayoutToPaintMsg::CanvasLayer(layer_id, renderer)).unwrap(); + } + + // Perform post-style recalculation layout passes. + self.perform_post_style_recalc_layout_passes(&data.reflow_info, + &mut rw_data, + &mut shared_layout_context); + + if let Some(mut root_flow) = self.root_flow.clone() { + match data.query_type { + ReflowQueryType::ContentBoxQuery(node) => { + let node = unsafe { ServoLayoutNode::new(&node) }; + rw_data.content_box_response = process_content_box_request(node, &mut root_flow); + }, + ReflowQueryType::ContentBoxesQuery(node) => { + let node = unsafe { ServoLayoutNode::new(&node) }; + rw_data.content_boxes_response = process_content_boxes_request(node, &mut root_flow); + }, + ReflowQueryType::NodeGeometryQuery(node) => { + let node = unsafe { ServoLayoutNode::new(&node) }; + rw_data.client_rect_response = process_node_geometry_request(node, &mut root_flow); + }, + ReflowQueryType::ResolvedStyleQuery(node, ref pseudo, ref property) => { + let node = unsafe { ServoLayoutNode::new(&node) }; + rw_data.resolved_style_response = + process_resolved_style_request(node, pseudo, property, &mut root_flow); + }, + ReflowQueryType::OffsetParentQuery(node) => { + let node = unsafe { ServoLayoutNode::new(&node) }; + rw_data.offset_parent_response = process_offset_parent_query(node, &mut root_flow); + }, + ReflowQueryType::NoQuery => {} + } + } + } + + fn set_visible_rects<'a, 'b>(&mut self, + new_visible_rects: Vec<(LayerId, Rect<Au>)>, + possibly_locked_rw_data: &mut RwData<'a, 'b>) + -> bool { + let mut rw_data = possibly_locked_rw_data.lock(); + + // First, determine if we need to regenerate the display lists. This will happen if the + // layers have moved more than `DISPLAY_PORT_THRESHOLD_SIZE_FACTOR` away from their last + // positions. + let mut must_regenerate_display_lists = false; + let mut old_visible_rects = HashMap::with_hash_state(Default::default()); + let inflation_amount = + Size2D::new(self.viewport_size.width * DISPLAY_PORT_THRESHOLD_SIZE_FACTOR, + self.viewport_size.height * DISPLAY_PORT_THRESHOLD_SIZE_FACTOR); + for &(ref layer_id, ref new_visible_rect) in &new_visible_rects { + match self.visible_rects.get(layer_id) { + None => { + old_visible_rects.insert(*layer_id, *new_visible_rect); + } + Some(old_visible_rect) => { + old_visible_rects.insert(*layer_id, *old_visible_rect); + + if !old_visible_rect.inflate(inflation_amount.width, inflation_amount.height) + .intersects(new_visible_rect) { + must_regenerate_display_lists = true; + } + } + } + } + + if !must_regenerate_display_lists { + // Update `visible_rects` in case there are new layers that were discovered. + self.visible_rects = Arc::new(old_visible_rects); + return true + } + + debug!("regenerating display lists!"); + for &(ref layer_id, ref new_visible_rect) in &new_visible_rects { + old_visible_rects.insert(*layer_id, *new_visible_rect); + } + self.visible_rects = Arc::new(old_visible_rects); + + // Regenerate the display lists. + let reflow_info = Reflow { + goal: ReflowGoal::ForDisplay, + page_clip_rect: MAX_RECT, + }; + + let mut layout_context = self.build_shared_layout_context(&*rw_data, + false, + &self.url.borrow(), + reflow_info.goal); + + self.perform_post_main_layout_passes(&reflow_info, &mut *rw_data, &mut layout_context); + true + } + + fn tick_all_animations<'a, 'b>(&mut self, possibly_locked_rw_data: &mut RwData<'a, 'b>) { + let mut rw_data = possibly_locked_rw_data.lock(); + self.tick_animations(&mut rw_data); + + self.script_chan + .send(ConstellationControlMsg::TickAllAnimations(self.id)) + .unwrap(); + } + + pub fn tick_animations(&mut self, rw_data: &mut LayoutThreadData) { + let reflow_info = Reflow { + goal: ReflowGoal::ForDisplay, + page_clip_rect: MAX_RECT, + }; + + let mut layout_context = self.build_shared_layout_context(&*rw_data, + false, + &self.url.borrow(), + reflow_info.goal); + + if let Some(mut root_flow) = self.root_flow.clone() { + // Perform an abbreviated style recalc that operates without access to the DOM. + let animations = self.running_animations.read().unwrap(); + profile(time::ProfilerCategory::LayoutStyleRecalc, + self.profiler_metadata(), + self.time_profiler_chan.clone(), + || { + animation::recalc_style_for_animations(flow_ref::deref_mut(&mut root_flow), + &*animations) + }); + } + + self.perform_post_style_recalc_layout_passes(&reflow_info, + &mut *rw_data, + &mut layout_context); + } + + fn reflow_with_newly_loaded_web_font<'a, 'b>(&mut self, possibly_locked_rw_data: &mut RwData<'a, 'b>) { + let mut rw_data = possibly_locked_rw_data.lock(); + font_context::invalidate_font_caches(); + + let reflow_info = Reflow { + goal: ReflowGoal::ForDisplay, + page_clip_rect: MAX_RECT, + }; + + let mut layout_context = self.build_shared_layout_context(&*rw_data, + false, + &self.url.borrow(), + reflow_info.goal); + + // No need to do a style recalc here. + if self.root_flow.is_none() { + return + } + self.perform_post_style_recalc_layout_passes(&reflow_info, + &mut *rw_data, + &mut layout_context); + } + + fn perform_post_style_recalc_layout_passes(&mut self, + data: &Reflow, + rw_data: &mut LayoutThreadData, + layout_context: &mut SharedLayoutContext) { + if let Some(mut root_flow) = self.root_flow.clone() { + // Kick off animations if any were triggered, expire completed ones. + animation::update_animation_state(&self.constellation_chan, + &mut *self.running_animations.write().unwrap(), + &mut *self.expired_animations.write().unwrap(), + &self.new_animations_receiver, + self.id); + + profile(time::ProfilerCategory::LayoutRestyleDamagePropagation, + self.profiler_metadata(), + self.time_profiler_chan.clone(), + || { + if opts::get().nonincremental_layout || + flow_ref::deref_mut(&mut root_flow).compute_layout_damage() + .contains(REFLOW_ENTIRE_DOCUMENT) { + flow_ref::deref_mut(&mut root_flow).reflow_entire_document() + } + }); + + if opts::get().trace_layout { + layout_debug::begin_trace(root_flow.clone()); + } + + // Resolve generated content. + profile(time::ProfilerCategory::LayoutGeneratedContent, + self.profiler_metadata(), + self.time_profiler_chan.clone(), + || sequential::resolve_generated_content(&mut root_flow, &layout_context)); + + // Perform the primary layout passes over the flow tree to compute the locations of all + // the boxes. + profile(time::ProfilerCategory::LayoutMain, + self.profiler_metadata(), + self.time_profiler_chan.clone(), + || { + let profiler_metadata = self.profiler_metadata(); + match self.parallel_traversal { + None => { + // Sequential mode. + LayoutThread::solve_constraints(&mut root_flow, &layout_context) + } + Some(ref mut parallel) => { + // Parallel mode. + LayoutThread::solve_constraints_parallel(parallel, + &mut root_flow, + profiler_metadata, + self.time_profiler_chan.clone(), + &*layout_context); + } + } + }); + + self.perform_post_main_layout_passes(data, rw_data, layout_context); + } + } + + fn perform_post_main_layout_passes(&mut self, + data: &Reflow, + rw_data: &mut LayoutThreadData, + layout_context: &mut SharedLayoutContext) { + // Build the display list if necessary, and send it to the painter. + if let Some(mut root_flow) = self.root_flow.clone() { + self.compute_abs_pos_and_build_display_list(data, + &mut root_flow, + &mut *layout_context, + rw_data); + self.first_reflow = false; + + if opts::get().trace_layout { + layout_debug::end_trace(); + } + + if opts::get().dump_flow_tree { + root_flow.print("Post layout flow tree".to_owned()); + } + + self.generation += 1; + } + } + + unsafe fn dirty_all_nodes<'ln, N: LayoutNode<'ln>>(node: N) { + for node in node.traverse_preorder() { + // TODO(cgaebel): mark nodes which are sensitive to media queries as + // "changed": + // > node.set_changed(true); + node.set_dirty(true); + node.set_dirty_descendants(true); + } + } + + fn reflow_all_nodes(flow: &mut Flow) { + debug!("reflowing all nodes!"); + flow::mut_base(flow).restyle_damage.insert(REFLOW | REPAINT); + + for child in flow::child_iter(flow) { + LayoutThread::reflow_all_nodes(child); + } + } + + /// Handles a message to destroy layout data. Layout data must be destroyed on *this* thread + /// because the struct type is transmuted to a different type on the script side. + unsafe fn handle_reap_style_and_layout_data(&self, data: OpaqueStyleAndLayoutData) { + let non_opaque: NonOpaqueStyleAndLayoutData = transmute(data.ptr); + let _ = Box::from_raw(non_opaque); + } + + /// Returns profiling information which is passed to the time profiler. + fn profiler_metadata(&self) -> Option<TimerMetadata> { + Some(TimerMetadata { + url: self.url.borrow().serialize(), + iframe: if self.is_iframe { + TimerMetadataFrameType::IFrame + } else { + TimerMetadataFrameType::RootWindow + }, + incremental: if self.first_reflow { + TimerMetadataReflowType::FirstReflow + } else { + TimerMetadataReflowType::Incremental + }, + }) + } +} + + +// The default computed value for background-color is transparent (see +// http://dev.w3.org/csswg/css-backgrounds/#background-color). However, we +// need to propagate the background color from the root HTML/Body +// element (http://dev.w3.org/csswg/css-backgrounds/#special-backgrounds) if +// it is non-transparent. The phrase in the spec "If the canvas background +// is not opaque, what shows through is UA-dependent." is handled by rust-layers +// clearing the frame buffer to white. This ensures that setting a background +// color on an iframe element, while the iframe content itself has a default +// transparent background color is handled correctly. +fn get_root_flow_background_color(flow: &mut Flow) -> AzColor { + if !flow.is_block_like() { + return color::transparent() + } + + let block_flow = flow.as_mut_block(); + let kid = match block_flow.base.children.iter_mut().next() { + None => return color::transparent(), + Some(kid) => kid, + }; + if !kid.is_block_like() { + return color::transparent() + } + + let kid_block_flow = kid.as_block(); + kid_block_flow.fragment + .style + .resolve_color(kid_block_flow.fragment.style.get_background().background_color) + .to_gfx_color() +} |