eliott/ladybird
1
0
Fork 0
mirror of https://github.com/LadybirdBrowser/ladybird synced 2026-04-26 01:35:08 +02:00
Code Issues Packages Projects Releases Wiki Activity

LibWeb: Rasterize each Navigable independently on its own thread

Browse Source 
Previously, iframes were rasterized synchronously as nested display
lists inside their parent's display list: the parent's paint walk called
record_display_list() on each hosted iframe document and emitted a
PaintNestedDisplayList command that the player would recurse into. Only
the top-level traversable's RenderingThread was ever active, even though
every Navigable already owned one.

The motivation for splitting this apart:
- Work in the outer document no longer has to be re-recorded when only
  an iframe changes. The parent's cached display list now references the
  iframe's rasterized output live via an ExternalContentSource, so an
  iframe invalidation just needs the parent's display list replayed, not
  re-recorded.
- Each iframe now has a self-contained rasterization pipeline, which is
  prep work for moving iframes into separate sandboxed processes.
This commit is contained in:
Aliaksandr Kalenik
2026-04-05 17:00:40 +02:00
committed by Alexander Kalenik
parent 115531eef1
commit ad2ee4fe7a
Notes: github-actions[bot] 2026-04-07 13:10:43 +00:00 
Author: https://github.com/kalenikaliaksandr
Commit: https://github.com/LadybirdBrowser/ladybird/commit/ad2ee4fe7ac
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/8793
8 changed files with 132 additions and 82 deletions
Download Patch File Download Diff File Expand all files Collapse all files

53
Libraries/LibWeb/HTML/Navigable.cpp
View File

@@ -53,7 +53,7 @@
#include <LibWeb/Loader/GeneratedPagesLoader.h>
#include <LibWeb/Page/Page.h>
#include <LibWeb/Painting/DisplayListPlayerSkia.h>
#include <LibWeb/Painting/NavigableContainerViewportPaintable.h>
#include <LibWeb/Painting/ExternalContentSource.h>
#include <LibWeb/Painting/Paintable.h>
#include <LibWeb/Painting/PaintableBox.h>
#include <LibWeb/Painting/ViewportPaintable.h>
@@ -421,6 +421,10 @@ void Navigable::initialize_navigable(NonnullRefPtr<DocumentState> document_state
// 5. Set navigable's parent to parent.
m_parent = parent;
if (parent && !m_is_svg_page) {
m_external_content_source = Painting::ExternalContentSource::create();
m_rendering_thread.set_presentation_mode(RenderingThread::PublishToExternalContent { external_content_source() });
}
// 6. Set the initial visibility state of documentState's document to navigable's traversable navigable's system visibility state.
document->set_initial_visibility_state(traversable_navigable()->system_visibility_state());
@@ -3087,6 +3091,12 @@ void Navigable::ready_to_paint()
m_rendering_thread.ready_to_paint();
}
NonnullRefPtr<Painting::ExternalContentSource> Navigable::external_content_source() const
{
VERIFY(m_external_content_source);
return *m_external_content_source;
}
void Navigable::record_display_list_and_scroll_state(PaintConfig paint_config)
{
m_needs_repaint = false;
@@ -3103,45 +3113,26 @@ void Navigable::record_display_list_and_scroll_state(PaintConfig paint_config)
document_paintable.refresh_scroll_state();
scroll_state_snapshot_by_display_list.set(*display_list, document_paintable.scroll_state_snapshot());
// Collect scroll state snapshots for each nested navigable
document_paintable.for_each_in_inclusive_subtree_of_type<Painting::NavigableContainerViewportPaintable>([&scroll_state_snapshot_by_display_list](auto& navigable_container_paintable) {
auto* hosted_document = navigable_container_paintable.navigable_container().content_document_without_origin_check();
if (!hosted_document)
return TraversalDecision::Continue;
// We can use unsafe_paintable() here since the scroll state collection only reads scroll offsets, which are
// valid even when layout is stale (e.g., a render-blocked iframe whose DOM was modified but whose scroll
// positions haven't changed).
auto* hosted_paintable = const_cast<Painting::ViewportPaintable*>(hosted_document->unsafe_paintable());
if (!hosted_paintable)
return TraversalDecision::Continue;
// We are only interested in collecting scroll state snapshots for visible nested navigables, which is
// detectable by checking if they have a cached display list that should've been populated by
// record_display_list() on top-level document.
auto navigable_display_list = hosted_document->cached_display_list();
if (!navigable_display_list)
return TraversalDecision::Continue;
hosted_paintable->refresh_scroll_state();
scroll_state_snapshot_by_display_list.set(*navigable_display_list, hosted_paintable->scroll_state_snapshot());
return TraversalDecision::Continue;
});
m_rendering_thread.update_display_list(*display_list, move(scroll_state_snapshot_by_display_list));
}
void Navigable::paint_next_frame()
{
if (!is_top_level_traversable())
return;
auto viewport_rect = page().css_to_device_rect(this->viewport_rect()).to_type<int>();
PaintConfig paint_config { .paint_overlay = true, .should_show_line_box_borders = m_should_show_line_box_borders, .canvas_fill_rect = Gfx::IntRect { {}, viewport_rect.size() } };
PaintConfig paint_config { .paint_overlay = true, .should_show_line_box_borders = m_should_show_line_box_borders };
if (is_top_level_traversable()) {
paint_config.canvas_fill_rect = Gfx::IntRect { {}, viewport_rect.size() };
} else {
// Nested navigables publish transparent bitmaps to their preconfigured ExternalContentSource instead of filling
// the canvas for the UI process.
VERIFY(m_external_content_source);
}
record_display_list_and_scroll_state(paint_config);
m_rendering_thread.present_frame(viewport_rect);
auto frame_id = m_rendering_thread.present_frame(viewport_rect);
if (!is_top_level_traversable())
m_rendering_thread.wait_for_frame(frame_id);
}
void Navigable::render_screenshot(Gfx::PaintingSurface& painting_surface, PaintConfig paint_config, Function<void()>&& callback)