Branch: refs/heads/main
Home: https://github.com/WebKit/WebKit
Commit: 8d7b28e8a7123325243f1521cfcf0abce5fd50c5
https://github.com/WebKit/WebKit/commit/8d7b28e8a7123325243f1521cfcf0abce5fd50c5
Author: Mike Wyrzykowski <[email protected]>
Date: 2025-11-04 (Tue, 04 Nov 2025)
Changed paths:
M Source/WebCore/platform/graphics/displaylists/DisplayListRecorder.cpp
M Source/WebCore/platform/graphics/displaylists/DisplayListRecorder.h
M Tools/TestWebKitAPI/Tests/WebCore/DisplayListRecorderTests.cpp
Log Message:
-----------
initialClip is not transformed by the CTM, leading to cursor clipping during
dictation
rdar://161084596
https://bugs.webkit.org/show_bug.cgi?id=301729
Reviewed by Simon Fraser.
There was a missing transform on the display list side with regards to initial
clip
and a duplicate transform occurring on the GraphicsContextCG side.
* Source/WebCore/platform/graphics/displaylists/DisplayListRecorder.cpp:
(WebCore::DisplayList::Recorder::Recorder):
As seen in Recorder's constructor, the state stack expects the clipping
matrix to be transformed:
m_stateStack.append({ state, initialCTM, initialCTM.mapRect(initialClip) });
but we had left m_initialClip assigned to the untranformed clip rect and then
later directly assigned it to currentState().clipBounds which incorrectly mapped
the untransformed clip rect to the clip bounds.
(WebCore::DisplayList::Recorder::updateStateForResetClip):
The GraphicsContextCG side is invoked via
RemoteGraphicsContextProxy::resetClip()
which calls Recorder::updateStateForClip() which we see:
currentState().clipBounds.intersect(currentState().ctm.mapRect(rect));
but when we pass initialClip(), we want the result of:
m_initialClip = CTM * (some matrix K) * m_initialClip
solving for K, K = CTM^(-1) which is what initialClip() returns now.
(WebCore::DisplayList::Recorder::initialClip const):
The CTM should always be invertible but handle the case, e.g., a zero
scale, where it is not invertible.
I hesitate to add a debug assertion as I'm not sure if there are valid
use cases for a zero transform which would cause the assertion to trigger.
* Source/WebCore/platform/graphics/displaylists/DisplayListRecorder.h:
(WebCore::DisplayList::Recorder::initialClip const): Deleted.
Moved to the .cpp file
* Tools/TestWebKitAPI/Tests/WebCore/DisplayListRecorderTests.cpp:
Update test to add a transform which would have detected this bug.
Canonical link: https://commits.webkit.org/302552@main
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