Title: [271356] trunk/Source/WebCore
- Revision
- 271356
- Author
- [email protected]
- Date
- 2021-01-11 03:15:28 -0800 (Mon, 11 Jan 2021)
Log Message
[css-multicol] Update fragment flow state on element insertion when element position changes
https://bugs.webkit.org/show_bug.cgi?id=202805
Reviewed by Zalan Bujtas.
Let's imagine the following scenario:
<div1 style="columns: 2">
<div2 style="columns:2; position: absolute">
<div3 style="column-span:all">
The generated render tree is more or less the following:
DIV
|__RenderMultiColumnFlow
|__DIV
|__RenderMultiColumnFlow
| |__RenderMultiColumnSpannerPlaceholder
|__DIV
|__RenderMultiColumnSet
both <div1> and <div2> generate RenderMultiColumnFlows because they're multicolumn containers while the <div3> becomes a spanner and leaves
a placeholder in the place where it's supposed to be as it's a "column-span:all". Note that <div2> is absolutely positioned so it isn't really
part of the column flow of <div1> (there is no RenderMultiColumnSet for <div1>). Now if the <div2> becomes a statically positioned container
(i.e. style="position:static") then it should be inserted (actually its whole subtree) in the <div1> multicolumn flow.
That insertion implies doing 2 things, first notify the RenderMultiColumnFlow of <div1> that a new child was inserted and secondly update the
flow state of the subtree which starts in <div2> so they acknowledge <div1> as their enclosing fragment flow. The former was properly done.
However the latter was not done at all, meaning that they would be treated as not belonging to any multicolumn flow when they actually did.
* rendering/updating/RenderTreeBuilder.cpp:
(WebCore::RenderTreeBuilder::childFlowStateChangesAndAffectsParentBlock): call initializeFragmentedFlowStateOnInsertion().
Modified Paths
Diff
Modified: trunk/Source/WebCore/ChangeLog (271355 => 271356)
--- trunk/Source/WebCore/ChangeLog 2021-01-11 10:31:00 UTC (rev 271355)
+++ trunk/Source/WebCore/ChangeLog 2021-01-11 11:15:28 UTC (rev 271356)
@@ -1,3 +1,38 @@
+2020-12-04 Sergio Villar Senin <[email protected]>
+
+ [css-multicol] Update fragment flow state on element insertion when element position changes
+ https://bugs.webkit.org/show_bug.cgi?id=202805
+
+ Reviewed by Zalan Bujtas.
+
+ Let's imagine the following scenario:
+
+ <div1 style="columns: 2">
+ <div2 style="columns:2; position: absolute">
+ <div3 style="column-span:all">
+
+ The generated render tree is more or less the following:
+
+ DIV
+ |__RenderMultiColumnFlow
+ |__DIV
+ |__RenderMultiColumnFlow
+ | |__RenderMultiColumnSpannerPlaceholder
+ |__DIV
+ |__RenderMultiColumnSet
+
+ both <div1> and <div2> generate RenderMultiColumnFlows because they're multicolumn containers while the <div3> becomes a spanner and leaves
+ a placeholder in the place where it's supposed to be as it's a "column-span:all". Note that <div2> is absolutely positioned so it isn't really
+ part of the column flow of <div1> (there is no RenderMultiColumnSet for <div1>). Now if the <div2> becomes a statically positioned container
+ (i.e. style="position:static") then it should be inserted (actually its whole subtree) in the <div1> multicolumn flow.
+
+ That insertion implies doing 2 things, first notify the RenderMultiColumnFlow of <div1> that a new child was inserted and secondly update the
+ flow state of the subtree which starts in <div2> so they acknowledge <div1> as their enclosing fragment flow. The former was properly done.
+ However the latter was not done at all, meaning that they would be treated as not belonging to any multicolumn flow when they actually did.
+
+ * rendering/updating/RenderTreeBuilder.cpp:
+ (WebCore::RenderTreeBuilder::childFlowStateChangesAndAffectsParentBlock): call initializeFragmentedFlowStateOnInsertion().
+
2021-01-11 Xabier Rodriguez Calvar <[email protected]>
[GStreamer] Add support to build with native audio and video
Modified: trunk/Source/WebCore/rendering/updating/RenderTreeBuilder.cpp (271355 => 271356)
--- trunk/Source/WebCore/rendering/updating/RenderTreeBuilder.cpp 2021-01-11 10:31:00 UTC (rev 271355)
+++ trunk/Source/WebCore/rendering/updating/RenderTreeBuilder.cpp 2021-01-11 11:15:28 UTC (rev 271356)
@@ -705,6 +705,7 @@
if (auto* newEnclosingFragmentedFlow = newParent->enclosingFragmentedFlow(); is<RenderMultiColumnFlow>(newEnclosingFragmentedFlow) && currentEnclosingFragment != newEnclosingFragmentedFlow) {
// Let the fragmented flow know that it has a new in-flow descendant.
multiColumnBuilder().multiColumnDescendantInserted(downcast<RenderMultiColumnFlow>(*newEnclosingFragmentedFlow), child);
+ child.initializeFragmentedFlowStateOnInsertion();
}
}
} else {
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