tor-browser

commit 8f823be747db655aef53348b58ea9de4f36c8834
parent 858a69d18649e870fa3967022e895bf5b8c5ef5c
Author: David Shin <dshin@mozilla.com>
Date:   Tue, 16 Dec 2025 20:17:34 +0000

Bug 2006398: Remove check for at least one inset in axis being auto for anchor-center use. r=layout-anchor-positioning-reviewers,layout-reviewers,emilio

Spec [1] doesn't make anchor-center depend on inset values; in fact, it forces
any `auto` inset to 0.

[1]: https://drafts.csswg.org/css-anchor-position-1/#anchor-center

Differential Revision: https://phabricator.services.mozilla.com/D276694

Diffstat:
M
layout/generic/ReflowInput.cpp
 | 
11
++---------
D
testing/web-platform/meta/css/css-anchor-position/auto-margins-position-area.html.ini
 | 
2
--

2 files changed, 2 insertions(+), 11 deletions(-)
diff --git a/layout/generic/ReflowInput.cpp b/layout/generic/ReflowInput.cpp
@@ -82,19 +82,12 @@ void ComputeAnchorCenterUsage(
   }
 
   const auto* stylePos = aFrame->StylePosition();
-  const auto parentWM = parent->GetWritingMode();
 
   auto checkAxis = [&](LogicalAxis aAxis) {
     StyleAlignFlags alignment =
         stylePos->UsedSelfAlignment(aAxis, parent->Style());
-    if ((alignment & ~StyleAlignFlags::FLAG_BITS) !=
-        StyleAlignFlags::ANCHOR_CENTER) {
-      return false;
-    }
-    LogicalSide startSide = MakeLogicalSide(aAxis, LogicalEdge::Start);
-    LogicalSide endSide = MakeLogicalSide(aAxis, LogicalEdge::End);
-    return stylePos->mOffset.Get(parentWM.PhysicalSide(startSide)).IsAuto() ||
-           stylePos->mOffset.Get(parentWM.PhysicalSide(endSide)).IsAuto();
+    return (alignment & ~StyleAlignFlags::FLAG_BITS) ==
+           StyleAlignFlags::ANCHOR_CENTER;
   };
 
   aInlineUsesAnchorCenter = checkAxis(LogicalAxis::Inline);
diff --git a/testing/web-platform/meta/css/css-anchor-position/auto-margins-position-area.html.ini b/testing/web-platform/meta/css/css-anchor-position/auto-margins-position-area.html.ini
@@ -1,2 +0,0 @@
-[auto-margins-position-area.html]
-  expected: FAIL