Branch: refs/heads/main
Home: https://github.com/WebKit/WebKit
Commit: 315fb715d136d0057225087b703abe6bffac7a82
https://github.com/WebKit/WebKit/commit/315fb715d136d0057225087b703abe6bffac7a82
Author: Nikolas Zimmermann <[email protected]>
Date: 2026-04-29 (Wed, 29 Apr 2026)
Changed paths:
M Source/WebCore/Headers.cmake
M Source/WebCore/WebCore.xcodeproj/project.pbxproj
M Source/WebCore/rendering/RenderElement.cpp
M Source/WebCore/rendering/RenderElement.h
M Source/WebCore/rendering/RenderLayer.cpp
M Source/WebCore/rendering/RenderLayer.h
M Source/WebCore/rendering/RenderLayerModelObject.cpp
M Source/WebCore/rendering/RenderLayerSVGAdditions.cpp
A Source/WebCore/rendering/RenderLayerSVGAdditions.h
M Source/WebCore/rendering/updating/RenderTreeBuilder.cpp
Log Message:
-----------
[LBSE] Introduce DOM-order children cache infrastructure for SVG layers
https://bugs.webkit.org/show_bug.cgi?id=313177
Reviewed by Simon Fraser.
Introduce the storage, invalidation, and collection of a cached, DOM-order
list of children for SVG layers. This infrastructure prepares for upcoming
SVG-specific painting and hit-testing that needs to walk children in DOM
order while interleaving layered and non-layered subtrees, and while
honoring z-index.
A new RenderLayerSVGAdditions.h header defines SVGPaintOrderLayerItem,
which classifies each entry via three factories:
1) makeLayered: the child has its own RenderLayer; the consumer will
delegate to the layer's own paint/hit-test machinery.
2) makeAtomic: a transformed non-layer SVG renderer, or any leaf - painted
in a single recursive pass at the precomputed ancestor offset.
3) makeOutlineOnly: a non-layer container whose subtree contains
independently painted descendants. The container is kept in the list
so its own self-outline still paints in DOM order, while its
descendants appear as separate entries; the container's own paint
must therefore skip child recursion to avoid double-painting.
RenderLayer::SVGData gains the cached vector plus a dirty flag.
childrenInDOMOrderForSVG() is the lazy accessor and rebuilds via
collectChildrenInDOMOrderForSVG() when dirty. Collection walks the render
tree recursively: layered descendants and transformed non-layer descendants
are appended directly, while non-layer containers are recursed
speculatively — kept as a split makeOutlineOnly entry if the subtree contains
any independently painted descendants, otherwise collapsed into a single
makeAtomic entry. The final list is stable-sorted by z-index only when at
least one child uses a non-zero z-index, so the common case stays in DOM
order without sort overhead. Storage uses Vector::shrink(0) on
invalidation and rebuild to retain capacity across churn.
The cache is dirtied via dirtyChildrenInDOMOrderForSVG(), wired into every
site that can change the list's membership, classification, or sort order:
- RenderLayer::dirtyPaintOrderListsOnChildChange, dirtyZOrderLists, and
dirtyNormalFlowList — layer-children changes within an SVG ancestor.
Note that the existing dirtyStackingContextZOrderLists() only dirties
the stacking context ancestor, not necessarily the immediate parent,
so an explicit dirty is required.
- The z-index branch of RenderLayer::styleChanged — z-index drives sort
order, so the parent layer's cache must be dirtied when it changes.
- RenderElement::insertedIntoTree and willBeRemovedFromTree, via the
new dirtyEnclosingLayerSVGChildrenIfNeeded() helper — non-layer SVG
renderers do not go through RenderLayer::addChild/removeChild, so
their insertion and removal must be intercepted at the RenderElement
level.
- RenderLayerModelObject::updateHasSVGTransformFlags and
repaintOrRelayoutAfterSVGTransformChange — when isTransformed() flips
on a non-layer renderer, its classification flips between Atomic and
the container path, requiring a rebuild of the enclosing layer's
cache.
- RenderTreeBuilder::detachFromRenderElement on the early-teardown
path, where resetRendererStateOnDetach() does not run and would
otherwise leave stale entries pointing into the detached subtree.
The cache has no consumers yet; they follow in subsequent patches.
Covered by existing tests once conditional-layer support is enabled.
* Source/WebCore/Headers.cmake:
* Source/WebCore/WebCore.xcodeproj/project.pbxproj:
* Source/WebCore/rendering/RenderElement.cpp:
(WebCore::RenderElement::dirtyEnclosingLayerSVGChildrenIfNeeded):
(WebCore::RenderElement::insertedIntoTree):
(WebCore::RenderElement::willBeRemovedFromTree):
* Source/WebCore/rendering/RenderElement.h:
* Source/WebCore/rendering/RenderLayer.cpp:
(WebCore::RenderLayer::dirtyPaintOrderListsOnChildChange):
(WebCore::RenderLayer::dirtyZOrderLists):
(WebCore::RenderLayer::dirtyNormalFlowList):
(WebCore::RenderLayer::calculateClipRects const):
* Source/WebCore/rendering/RenderLayer.h:
* Source/WebCore/rendering/RenderLayerModelObject.cpp:
(WebCore::RenderLayerModelObject::updateHasSVGTransformFlags):
(WebCore::RenderLayerModelObject::repaintOrRelayoutAfterSVGTransformChange):
* Source/WebCore/rendering/RenderLayerSVGAdditions.cpp:
(WebCore::RenderLayer::dirtyChildrenInDOMOrderForSVG):
(WebCore::RenderLayer::collectChildrenInDOMOrderForSVG):
(WebCore::RenderLayer::appendChildrenInDOMOrderForSVG):
(WebCore::RenderLayer::childrenInDOMOrderForSVG):
* Source/WebCore/rendering/RenderLayerSVGAdditions.h: Added.
(WebCore::SVGPaintOrderLayerItem::makeLayered):
(WebCore::SVGPaintOrderLayerItem::makeAtomic):
(WebCore::SVGPaintOrderLayerItem::makeOutlineOnly):
(WebCore::SVGPaintOrderLayerItem::SVGPaintOrderLayerItem):
* Source/WebCore/rendering/updating/RenderTreeBuilder.cpp:
(WebCore::RenderTreeBuilder::detachFromRenderElement):
Canonical link: https://commits.webkit.org/312337@main
To unsubscribe from these emails, change your notification settings at
https://github.com/WebKit/WebKit/settings/notifications
