mpadded lspace attribute incorrectly positions content in RTL direction

Ahmad-S792 · Ahmad Saleem · commit d67021780499 · 2025-12-08T04:40:15.000-08:00
https://bugs.webkit.org/show_bug.cgi?id=303735 rdar://166045517 Reviewed by Frédéric Wang. In RTL mode, lspace should add space on the inline-start (physical right) side. The previous implementation added in 303070@main simply negated lspace, which incorrectly positioned content at the left edge instead of accounting for the box width and content width. For RTL with lspace="25px", width="150px", and content width 75px: - Content should end 25px from the right edge - Content starts at: 150 - 25 - 75 = 50px from left The fix calculates RTL inline shift as (width - contentWidth - lspace()) to properly position content relative to the box's right edge. * Source/WebCore/rendering/mathml/RenderMathMLPadded.cpp: (WebCore::RenderMathMLPadded::layoutBlock): * LayoutTests/TestExpectations: Progression Canonical link: https://commits.webkit.org/304087@main
diff --git a/LayoutTests/TestExpectations b/LayoutTests/TestExpectations
@@ -1968,7 +1968,6 @@ imported/w3c/web-platform-tests/html/browsers/windows/nested-browsing-contexts/f
 # These MathML WPT tests fail.
 webkit.org/b/180013 mathml/non-core/lengths-2.html [ ImageOnlyFailure ]
 webkit.org/b/194952 imported/w3c/web-platform-tests/mathml/presentation-markup/fractions/frac-bar-001.html [ ImageOnlyFailure ]
-imported/w3c/web-platform-tests/mathml/presentation-markup/direction/direction-mpadded.html [ ImageOnlyFailure ]
 imported/w3c/web-platform-tests/mathml/presentation-markup/direction/direction-overall-003.html [ ImageOnlyFailure ]
 imported/w3c/web-platform-tests/mathml/presentation-markup/fractions/frac-bar-002.html [ ImageOnlyFailure ]
 imported/w3c/web-platform-tests/mathml/presentation-markup/fractions/frac-default-padding.html [ ImageOnlyFailure ]
diff --git a/Source/WebCore/rendering/mathml/RenderMathMLPadded.cpp b/Source/WebCore/rendering/mathml/RenderMathMLPadded.cpp
@@ -120,7 +120,7 @@ void RenderMathMLPadded::layoutBlock(RelayoutChildren relayoutChildren, LayoutUn
     LayoutUnit ascent = mpaddedHeight(contentAscent);
     LayoutUnit descent = mpaddedDepth(contentDescent);
 
-    auto inlineShift = style().writingMode().inlineDirection() == FlowDirection::RightToLeft ? -lspace() : lspace();
+    auto inlineShift = style().writingMode().inlineDirection() == FlowDirection::RightToLeft ? (width - contentWidth - lspace()) : lspace();
 
     // Align children on the new baseline and shift them by (lspace, -voffset)
     shiftInFlowChildren(inlineShift, ascent - contentAscent - voffset());
