tor-browser

commit 1f2deb0d232c0ad552035107b2f3eef198db2178
parent b1abbd349f0b67efffa2d7fbeaaaf590869f9bc2
Author: David Shin <dshin@mozilla.com>
Date:   Thu, 18 Dec 2025 18:44:12 +0000

Bug 2006402: Use physical axes for flagging anchor-center use. r=layout-anchor-positioning-reviewers,firefox-style-system-reviewers,emilio

... Everything is in physical axes at resolution time, so front-load the
mapping from logical to physical when the resolution params are set up.

Differential Revision: https://phabricator.services.mozilla.com/D276907

Diffstat:
M
layout/style/nsStyleStruct.cpp
 | 
44
++++++++++----------------------------------
M
layout/style/nsStyleStruct.h
 | 
19
+++++++------------

2 files changed, 17 insertions(+), 46 deletions(-)
diff --git a/layout/style/nsStyleStruct.cpp b/layout/style/nsStyleStruct.cpp
@@ -288,33 +288,7 @@ static StyleRect<T> StyleRectWithAllSides(const T& aSide) {
 }
 
 bool AnchorPosResolutionParams::AutoResolutionOverrideParams::OverriddenToZero(
-    StylePhysicalAxis aAxis, const nsIFrame* aFrame) const {
-  if (!aFrame || !aFrame->HasAnyStateBits(NS_FRAME_OUT_OF_FLOW)) {
-    return false;
-  }
-  const auto* cb = aFrame->GetParent();
-  const auto cbwm = cb->GetWritingMode();
-  const auto logicalAxis = [&]() {
-    if (cbwm.IsVertical()) {
-      return aAxis == StylePhysicalAxis::Vertical ? LogicalAxis::Inline
-                                                  : LogicalAxis::Block;
-    }
-    return aAxis == StylePhysicalAxis::Horizontal ? LogicalAxis::Inline
-                                                  : LogicalAxis::Block;
-  }();
-  return OverriddenToZero(logicalAxis);
-}
-
-bool AnchorPosResolutionParams::AutoResolutionOverrideParams::OverriddenToZero(
-    Side aSide, const nsIFrame* aFrame) const {
-  return OverriddenToZero(aSide == Side::eSideBottom || aSide == Side::eSideTop
-                              ? StylePhysicalAxis::Vertical
-                              : StylePhysicalAxis::Horizontal,
-                          aFrame);
-}
-
-bool AnchorPosResolutionParams::AutoResolutionOverrideParams::OverriddenToZero(
-    LogicalAxis aAxis) const {
+    StylePhysicalAxis aAxis) const {
   if (mPositionAreaInUse) {
     // If `position-area` is used "Any auto inset properties resolve to 0":
     // https://drafts.csswg.org/css-anchor-position-1/#valdef-position-area-position-area
@@ -324,12 +298,11 @@ bool AnchorPosResolutionParams::AutoResolutionOverrideParams::OverriddenToZero(
   // If `anchor-center` is used with a valid anchor, "auto inset
   // properties resolve to 0" on that axis:
   // https://drafts.csswg.org/css-anchor-position-1/#anchor-center
-  switch (aAxis) {
-    case LogicalAxis::Block:
-      return mBAnchorCenter;
-    case LogicalAxis::Inline:
-      return mIAnchorCenter;
+  if (aAxis == StylePhysicalAxis::Vertical) {
+    return mVAnchorCenter;
   }
+  MOZ_ASSERT(aAxis == StylePhysicalAxis::Horizontal);
+  return mHAnchorCenter;
 }
 
 AnchorPosResolutionParams::AutoResolutionOverrideParams::
@@ -343,6 +316,7 @@ AnchorPosResolutionParams::AutoResolutionOverrideParams::
   }
 
   const auto* stylePos = aFrame->StylePosition();
+  const auto cbwm = parent->GetWritingMode();
 
   auto checkAxis = [&](LogicalAxis aAxis) {
     StyleAlignFlags alignment =
@@ -351,8 +325,10 @@ AnchorPosResolutionParams::AutoResolutionOverrideParams::
            StyleAlignFlags::ANCHOR_CENTER;
   };
 
-  mIAnchorCenter = checkAxis(LogicalAxis::Inline);
-  mBAnchorCenter = checkAxis(LogicalAxis::Block);
+  const auto horizontalLogicalAxis =
+      cbwm.IsVertical() ? LogicalAxis::Block : LogicalAxis::Inline;
+  mHAnchorCenter = checkAxis(horizontalLogicalAxis);
+  mVAnchorCenter = checkAxis(GetOrthogonalAxis(horizontalLogicalAxis));
   mPositionAreaInUse = !stylePos->mPositionArea.IsNone();
 }
 
diff --git a/layout/style/nsStyleStruct.h b/layout/style/nsStyleStruct.h
@@ -379,11 +379,10 @@ using AnchorResolvedMargin =
 // Base set of parameters required to resolve a reference to an anchor.
 struct AnchorPosResolutionParams {
   struct AutoResolutionOverrideParams {
-    // TODO(dshin): Probably just make it physical
-    // Whether anchor-center is being used on the inline axis.
-    bool mIAnchorCenter = false;
-    // Whether anchor-center is being used on the block axis.
-    bool mBAnchorCenter = false;
+    // Whether anchor-center is being used on the horizontal axis.
+    bool mHAnchorCenter = false;
+    // Whether anchor-center is being used on the vertical axis.
+    bool mVAnchorCenter = false;
     // Whether position-area is being used.
     bool mPositionAreaInUse = false;
 
@@ -392,10 +391,7 @@ struct AnchorPosResolutionParams {
         const nsIFrame* aFrame,
         const mozilla::AnchorPosResolutionCache* aCache);
 
-    bool OverriddenToZero(mozilla::StylePhysicalAxis aAxis,
-                          const nsIFrame* aFrame) const;
-    bool OverriddenToZero(mozilla::Side aSide, const nsIFrame* aFrame) const;
-    bool OverriddenToZero(mozilla::LogicalAxis aAxis) const;
+    bool OverriddenToZero(mozilla::StylePhysicalAxis aAxis) const;
   };
   // Frame of the anchor positioned element.
   // If nullptr, skips anchor lookup and returns invalid, resolving fallbacks.
@@ -437,8 +433,7 @@ struct AnchorResolvedMarginHelper {
       return AnchorResolvedMargin::NonOwning(&aValue);
     }();
     if (resolved->IsAuto() &&
-        aParams.mAutoResolutionOverrideParams.OverriddenToZero(
-            aAxis, aParams.mFrame)) {
+        aParams.mAutoResolutionOverrideParams.OverriddenToZero(aAxis)) {
       return Zero();
     }
     return resolved;
@@ -814,7 +809,7 @@ struct AnchorResolvedInsetHelper {
     }();
     if (resolved->IsAuto() &&
         aParams.mBaseParams.mAutoResolutionOverrideParams.OverriddenToZero(
-            aSide, aParams.mBaseParams.mFrame)) {
+            mozilla::ToStylePhysicalAxis(aSide))) {
       return AnchorResolvedInset::NonOwning(&ZeroValue());
     }
     return resolved;