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compositing: Move image output and shutdown management out of the compositor (#35538)

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This is a step toward the renderer-per-WebView goal. It moves various
details out of `IOCompositor`.

- Image output: This is moved to servoshell as now applications can
  access the image contents of a `WebView` via
  `RenderingContext::read_to_image`. Most options for this are moved to
  `ServoShellPreferences` apart from `wait_for_stable_image` as this
  requires a specific kind of coordination in the `ScriptThread` that is
  also very expensive. Instead, paint is now simply delayed until a
  stable image is reached and `WebView::paint()` returns a boolean.
  Maybe this can be revisited in the future.
- Shutdown: Shutdown is now managed by libservo itself. Shutdown state
  is shared between the compositor and `Servo` instance. In the future,
  this sharing might be unecessary.
- `CompositeTarget` has been removed entirely. This no longer needs to
   be passed when creating a Servo instance.

Signed-off-by: Martin Robinson <mrobinson@igalia.com>
Co-authored-by: Ngo Iok Ui (Wu Yu Wei) <yuweiwu@pm.me>
This commit is contained in:
Martin Robinson 2025-02-20 19:27:49 +01:00 • committed by GitHub
parent 7d33e72bfc
commit 54b5c7b632
No known key found for this signature in database
GPG key ID: B5690EEEBB952194
25 changed files with 233 additions and 270 deletions
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1
components/compositing/Cargo.toml
View file

@ -26,7 +26,6 @@ embedder_traits = { workspace = true }
euclid = { workspace = true }
fnv = { workspace = true }
gleam = { workspace = true }
image = { workspace = true }
ipc-channel = { workspace = true }
libc = { workspace = true }
log = { workspace = true }

240
components/compositing/compositor.rs
View file

@ -22,11 +22,10 @@ use compositing_traits::{
use crossbeam_channel::Sender;
use embedder_traits::{
Cursor, InputEvent, MouseButton, MouseButtonAction, MouseButtonEvent, MouseMoveEvent,
TouchAction, TouchEvent, TouchEventType, TouchId,
ShutdownState, TouchAction, TouchEvent, TouchEventType, TouchId,
};
use euclid::{Point2D, Rect, Scale, Size2D, Transform3D, Vector2D};
use fnv::{FnvHashMap, FnvHashSet};
use image::{DynamicImage, ImageFormat};
use ipc_channel::ipc::{self, IpcSharedMemory};
use libc::c_void;
use log::{debug, error, info, trace, warn};
@ -37,6 +36,7 @@ use script_traits::{
AnimationState, AnimationTickType, EventResult, ScriptThreadMessage, ScrollState,
WindowSizeData, WindowSizeType,
};
use servo_config::opts;
use servo_geometry::DeviceIndependentPixel;
use style_traits::{CSSPixel, PinchZoomFactor};
use webrender::{CaptureBits, RenderApi, Transaction};
@ -102,8 +102,8 @@ pub struct ServoRenderer {
webviews: WebViewManager<WebView>,
/// Tracks whether we are in the process of shutting down, or have shut down and should close
/// the compositor.
shutdown_state: ShutdownState,
/// the compositor. This is shared with the `Servo` instance.
shutdown_state: Rc<Cell<ShutdownState>>,
/// The port on which we receive messages.
compositor_receiver: CompositorReceiver,
@ -120,9 +120,6 @@ pub struct ServoRenderer {
/// The GL bindings for webrender
webrender_gl: Rc<dyn gleam::gl::Gl>,
/// True to exit after page load ('-x').
exit_after_load: bool,
/// The string representing the version of Servo that is running. This is used to tag
/// WebRender capture output.
version_string: String,
@ -153,9 +150,6 @@ pub struct IOCompositor {
/// "Desktop-style" zoom that resizes the viewport to fit the window.
page_zoom: Scale<f32, CSSPixel, DeviceIndependentPixel>,
/// The type of composition to perform
composite_target: CompositeTarget,
/// Tracks whether or not the view needs to be repainted.
needs_repaint: Cell<RepaintReason>,
@ -250,13 +244,6 @@ bitflags! {
}
}
#[derive(Clone, Copy, Debug, PartialEq)]
pub enum ShutdownState {
NotShuttingDown,
ShuttingDown,
FinishedShuttingDown,
}
struct PipelineDetails {
/// The pipeline associated with this PipelineDetails object.
pipeline: Option<CompositionPipeline>,
@ -324,38 +311,22 @@ impl PipelineDetails {
}
}
#[derive(Clone, Debug, PartialEq)]
pub enum CompositeTarget {
/// Draw to a OpenGL framebuffer object that will then be used by the compositor to composite
/// to [`RenderingContext::framebuffer_object`]
ContextFbo,
/// Draw to an uncompressed image in shared memory.
SharedMemory,
/// Draw to a PNG file on disk, then exit the browser (for reftests).
PngFile(Rc<String>),
}
impl IOCompositor {
pub fn new(
window: Rc<dyn WindowMethods>,
state: InitialCompositorState,
composite_target: CompositeTarget,
exit_after_load: bool,
convert_mouse_to_touch: bool,
version_string: String,
) -> Self {
let compositor = IOCompositor {
global: ServoRenderer {
shutdown_state: ShutdownState::NotShuttingDown,
shutdown_state: state.shutdown_state,
webviews: WebViewManager::default(),
compositor_receiver: state.receiver,
constellation_sender: state.constellation_chan,
time_profiler_chan: state.time_profiler_chan,
webrender_api: state.webrender_api,
webrender_gl: state.webrender_gl,
exit_after_load,
version_string,
#[cfg(feature = "webxr")]
webxr_main_thread: state.webxr_main_thread,
@ -366,7 +337,6 @@ impl IOCompositor {
needs_repaint: Cell::default(),
touch_handler: TouchHandler::new(),
pending_scroll_zoom_events: Vec::new(),
composite_target,
page_zoom: Scale::new(1.0),
viewport_zoom: PinchZoomFactor::new(1.0),
min_viewport_zoom: Some(PinchZoomFactor::new(1.0)),
@ -394,7 +364,7 @@ impl IOCompositor {
}
pub fn shutdown_state(&self) -> ShutdownState {
self.global.shutdown_state
self.global.shutdown_state.get()
}
pub fn deinit(&mut self) {
@ -441,27 +411,7 @@ impl IOCompositor {
}
}
pub fn start_shutting_down(&mut self) {
if self.global.shutdown_state != ShutdownState::NotShuttingDown {
warn!("Requested shutdown while already shutting down");
return;
}
debug!("Compositor sending Exit message to Constellation");
if let Err(e) = self
.global
.constellation_sender
.send(ConstellationMsg::Exit)
{
warn!("Sending exit message to constellation failed ({:?}).", e);
}
self.global.shutdown_state = ShutdownState::ShuttingDown;
}
fn finish_shutting_down(&mut self) {
debug!("Compositor received message that constellation shutdown is complete");
pub fn finish_shutting_down(&mut self) {
// Drain compositor port, sometimes messages contain channels that are blocking
// another thread from finishing (i.e. SetFrameTree).
while self
@ -478,14 +428,12 @@ impl IOCompositor {
.send(profile_time::ProfilerMsg::Exit(sender));
let _ = receiver.recv();
}
self.global.shutdown_state = ShutdownState::FinishedShuttingDown;
}
fn handle_browser_message(&mut self, msg: CompositorMsg) {
trace_msg_from_constellation!(msg, "{msg:?}");
match self.global.shutdown_state {
match self.shutdown_state() {
ShutdownState::NotShuttingDown => {},
ShutdownState::ShuttingDown => {
self.handle_browser_message_while_shutting_down(msg);
@ -498,11 +446,6 @@ impl IOCompositor {
}
match msg {
CompositorMsg::ShutdownComplete => {
error!("Received `ShutdownComplete` while not shutting down.");
self.finish_shutting_down();
},
CompositorMsg::ChangeRunningAnimationsState(pipeline_id, animation_state) => {
self.change_running_animations_state(pipeline_id, animation_state);
},
@ -521,7 +464,7 @@ impl IOCompositor {
},
CompositorMsg::CreatePng(page_rect, reply) => {
let res = self.composite_specific_target(CompositeTarget::SharedMemory, page_rect);
let res = self.render_to_shared_memory(page_rect);
if let Err(ref e) = res {
info!("Error retrieving PNG: {:?}", e);
}
@ -570,10 +513,7 @@ impl IOCompositor {
},
CompositorMsg::LoadComplete(_) => {
// If we're painting in headless mode, schedule a recomposite.
if matches!(self.composite_target, CompositeTarget::PngFile(_)) ||
self.global.exit_after_load
{
if opts::get().wait_for_stable_image {
self.set_needs_repaint(RepaintReason::ReadyForScreenshot);
}
},
@ -850,9 +790,6 @@ impl IOCompositor {
/// compositor no longer does any WebRender frame generation.
fn handle_browser_message_while_shutting_down(&mut self, msg: CompositorMsg) {
match msg {
CompositorMsg::ShutdownComplete => {
self.finish_shutting_down();
},
CompositorMsg::PipelineExited(pipeline_id, sender) => {
debug!("Compositor got pipeline exited: {:?}", pipeline_id);
self.remove_pipeline_root_layer(pipeline_id);
@ -1299,7 +1236,7 @@ impl IOCompositor {
}
pub fn on_rendering_context_resized(&mut self) -> bool {
if self.global.shutdown_state != ShutdownState::NotShuttingDown {
if self.shutdown_state() != ShutdownState::NotShuttingDown {
return false;
}
@ -1352,7 +1289,7 @@ impl IOCompositor {
}
pub fn on_input_event(&mut self, event: InputEvent) {
if self.global.shutdown_state != ShutdownState::NotShuttingDown {
if self.shutdown_state() != ShutdownState::NotShuttingDown {
return;
}
@ -1465,7 +1402,7 @@ impl IOCompositor {
}
pub fn on_touch_event(&mut self, event: TouchEvent) {
if self.global.shutdown_state != ShutdownState::NotShuttingDown {
if self.shutdown_state() != ShutdownState::NotShuttingDown {
return;
}
@ -1605,7 +1542,7 @@ impl IOCompositor {
cursor: DeviceIntPoint,
event_type: TouchEventType,
) {
if self.global.shutdown_state != ShutdownState::NotShuttingDown {
if self.shutdown_state() != ShutdownState::NotShuttingDown {
return;
}
@ -1822,9 +1759,6 @@ impl IOCompositor {
}
fn hidpi_factor(&self) -> Scale<f32, DeviceIndependentPixel, DevicePixel> {
if matches!(self.composite_target, CompositeTarget::PngFile(_)) {
return Scale::new(1.0);
}
self.embedder_coordinates.hidpi_factor
}
@ -1839,7 +1773,7 @@ impl IOCompositor {
}
pub fn on_zoom_reset_window_event(&mut self) {
if self.global.shutdown_state != ShutdownState::NotShuttingDown {
if self.shutdown_state() != ShutdownState::NotShuttingDown {
return;
}
@ -1848,7 +1782,7 @@ impl IOCompositor {
}
pub fn on_zoom_window_event(&mut self, magnification: f32) {
if self.global.shutdown_state != ShutdownState::NotShuttingDown {
if self.shutdown_state() != ShutdownState::NotShuttingDown {
return;
}
@ -1871,7 +1805,7 @@ impl IOCompositor {
/// Simulate a pinch zoom
pub fn on_pinch_zoom_window_event(&mut self, magnification: f32) {
if self.global.shutdown_state != ShutdownState::NotShuttingDown {
if self.shutdown_state() != ShutdownState::NotShuttingDown {
return;
}
@ -1985,10 +1919,12 @@ impl IOCompositor {
}
}
pub fn composite(&mut self) {
if let Err(error) = self.composite_specific_target(self.composite_target.clone(), None) {
warn!("Unable to composite: {error:?}");
return;
/// Render the WebRender scene to the active `RenderingContext`. If successful, trigger
/// the next round of animations.
pub fn render(&mut self) -> bool {
if let Err(error) = self.render_inner() {
warn!("Unable to render: {error:?}");
return false;
}
// We've painted the default target, which means that from the embedder's perspective,
@ -1998,28 +1934,54 @@ impl IOCompositor {
// Queue up any subsequent paints for animations.
self.process_animations(true);
if matches!(self.composite_target, CompositeTarget::PngFile(_)) ||
self.global.exit_after_load
{
println!("Shutting down the Constellation after generating an output file or exit flag specified");
self.start_shutting_down();
}
true
}
/// Render the WebRender scene to the shared memory, without updating other state of this
/// [`IOCompositor`]. If succesful return the output image in shared memory.
fn render_to_shared_memory(
&mut self,
page_rect: Option<Rect<f32, CSSPixel>>,
) -> Result<Option<Image>, UnableToComposite> {
self.render_inner()?;
let size = self.embedder_coordinates.framebuffer.to_u32();
let (x, y, width, height) = if let Some(rect) = page_rect {
let rect = self.device_pixels_per_page_pixel().transform_rect(&rect);
let x = rect.origin.x as i32;
// We need to convert to the bottom-left origin coordinate
// system used by OpenGL
let y = (size.height as f32 - rect.origin.y - rect.size.height) as i32;
let w = rect.size.width as u32;
let h = rect.size.height as u32;
(x, y, w, h)
} else {
(0, 0, size.width, size.height)
};
Ok(self
.rendering_context
.read_to_image(Rect::new(
Point2D::new(x as u32, y as u32),
Size2D::new(width, height),
))
.map(|image| Image {
width: image.width(),
height: image.height(),
format: PixelFormat::RGBA8,
bytes: ipc::IpcSharedMemory::from_bytes(&image),
id: None,
cors_status: CorsStatus::Safe,
}))
}
/// Composite to the given target if any, or the current target otherwise.
/// Returns Ok if composition was performed or Err if it was not possible to composite for some
/// reason. When the target is [CompositeTarget::SharedMemory], the image is read back from the
/// GPU and returned as Ok(Some(png::Image)), otherwise we return Ok(None).
#[cfg_attr(
feature = "tracing",
tracing::instrument(skip_all, fields(servo_profiling = true), level = "trace")
)]
fn composite_specific_target(
&mut self,
target: CompositeTarget,
page_rect: Option<Rect<f32, CSSPixel>>,
) -> Result<Option<Image>, UnableToComposite> {
let size = self.embedder_coordinates.framebuffer.to_u32();
fn render_inner(&mut self) -> Result<(), UnableToComposite> {
if let Err(err) = self.rendering_context.make_current() {
warn!("Failed to make the rendering context current: {:?}", err);
}
@ -2029,12 +1991,7 @@ impl IOCompositor {
webrender.update();
}
let wait_for_stable_image = matches!(
target,
CompositeTarget::SharedMemory | CompositeTarget::PngFile(_)
) || self.global.exit_after_load;
if wait_for_stable_image {
if opts::get().wait_for_stable_image {
// The current image may be ready to output. However, if there are animations active,
// tick those instead and continue waiting for the image output to be stable AND
// all active animations to complete.
@ -2071,64 +2028,7 @@ impl IOCompositor {
);
self.send_pending_paint_metrics_messages_after_composite();
let (x, y, width, height) = if let Some(rect) = page_rect {
let rect = self.device_pixels_per_page_pixel().transform_rect(&rect);
let x = rect.origin.x as i32;
// We need to convert to the bottom-left origin coordinate
// system used by OpenGL
let y = (size.height as f32 - rect.origin.y - rect.size.height) as i32;
let w = rect.size.width as u32;
let h = rect.size.height as u32;
(x, y, w, h)
} else {
(0, 0, size.width, size.height)
};
let rv = match target {
CompositeTarget::ContextFbo => None,
CompositeTarget::SharedMemory => self
.rendering_context
.read_to_image(Rect::new(
Point2D::new(x as u32, y as u32),
Size2D::new(width, height),
))
.map(|image| Image {
width: image.width(),
height: image.height(),
format: PixelFormat::RGBA8,
bytes: ipc::IpcSharedMemory::from_bytes(&image),
id: None,
cors_status: CorsStatus::Safe,
}),
CompositeTarget::PngFile(path) => {
time_profile!(
ProfilerCategory::ImageSaving,
None,
self.global.time_profiler_chan.clone(),
|| match File::create(&*path) {
Ok(mut file) => {
if let Some(image) = self.rendering_context.read_to_image(Rect::new(
Point2D::new(x as u32, y as u32),
Size2D::new(width, height),
)) {
let dynamic_image = DynamicImage::ImageRgba8(image);
if let Err(e) = dynamic_image.write_to(&mut file, ImageFormat::Png)
{
error!("Failed to save {} ({}).", path, e);
}
}
},
Err(e) => error!("Failed to create {} ({}).", path, e),
},
);
None
},
};
Ok(rv)
Ok(())
}
/// Send all pending paint metrics messages after a composite operation, which may advance
@ -2257,7 +2157,7 @@ impl IOCompositor {
for msg in compositor_messages {
self.handle_browser_message(msg);
if self.global.shutdown_state == ShutdownState::FinishedShuttingDown {
if self.shutdown_state() == ShutdownState::FinishedShuttingDown {
return;
}
}
@ -2268,7 +2168,7 @@ impl IOCompositor {
tracing::instrument(skip_all, fields(servo_profiling = true), level = "trace")
)]
pub fn perform_updates(&mut self) -> bool {
if self.global.shutdown_state == ShutdownState::FinishedShuttingDown {
if self.shutdown_state() == ShutdownState::FinishedShuttingDown {
return false;
}
@ -2292,7 +2192,7 @@ impl IOCompositor {
if !self.pending_scroll_zoom_events.is_empty() {
self.process_pending_scroll_events()
}
self.global.shutdown_state != ShutdownState::FinishedShuttingDown
self.shutdown_state() != ShutdownState::FinishedShuttingDown
}
pub fn pinch_zoom_level(&self) -> Scale<f32, DevicePixel, DevicePixel> {

7
components/compositing/lib.rs
View file

@ -4,16 +4,18 @@
#![deny(unsafe_code)]
use std::cell::Cell;
use std::rc::Rc;
use compositing_traits::{CompositorProxy, CompositorReceiver, ConstellationMsg};
use crossbeam_channel::Sender;
use embedder_traits::ShutdownState;
use profile_traits::{mem, time};
use webrender::RenderApi;
use webrender_api::DocumentId;
use webrender_traits::rendering_context::RenderingContext;
pub use crate::compositor::{CompositeTarget, IOCompositor, ShutdownState};
pub use crate::compositor::IOCompositor;
#[macro_use]
mod tracing;
@ -35,6 +37,9 @@ pub struct InitialCompositorState {
pub time_profiler_chan: time::ProfilerChan,
/// A channel to the memory profiler thread.
pub mem_profiler_chan: mem::ProfilerChan,
/// A shared state which tracks whether Servo has started or has finished
/// shutting down.
pub shutdown_state: Rc<Cell<ShutdownState>>,
/// Instance of webrender API
pub webrender: webrender::Renderer,
pub webrender_document: DocumentId,

1
components/compositing/tracing.rs
View file

@ -30,7 +30,6 @@ mod from_constellation {
impl LogTarget for compositing_traits::CompositorMsg {
fn log_target(&self) -> &'static str {
match self {
Self::ShutdownComplete => target!("ShutdownComplete"),
Self::ChangeRunningAnimationsState(..) => target!("ChangeRunningAnimationsState"),
Self::CreateOrUpdateWebView(..) => target!("CreateOrUpdateWebView"),
Self::RemoveWebView(..) => target!("RemoveWebView"),