Changeset 272118 in webkit

Timestamp:

Jan 30, 2021, 11:34:48 AM (6 years ago)

Author:

Alan Bujtas

Message:

[LFC][IFC] Line gap metric should apply to all inline boxes
​https://bugs.webkit.org/show_bug.cgi?id=221179

Reviewed by Antti Koivisto.

According to the CSS spec (​https://www.w3.org/TR/css-inline-3/#inline-height)
when the line-height computes to normal (RenderStyle::lineHeight().isNegative()) and
either text-edge is leading (property is not supported yet, initial value is leading) or
this is the root inline box, the font’s line gap should be taken into account when computing
layout bounds.

• layout/inlineformatting/InlineFormattingContextGeometry.cpp:

(WebCore::Layout::LineBoxBuilder::setVerticalGeometryForInlineBox const):

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• layout/inlineformatting/InlineFormattingContextGeometry.cpp (modified) (1 diff)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2021-01-30  Zalan Bujtas  <zalan@apple.com>
+
+        [LFC][IFC] Line gap metric should apply to all inline boxes
+        https://bugs.webkit.org/show_bug.cgi?id=221179
+
+        Reviewed by Antti Koivisto.
+
+        According to the CSS spec (https://www.w3.org/TR/css-inline-3/#inline-height)
+        when the line-height computes to normal (RenderStyle::lineHeight().isNegative()) and
+        either text-edge is leading (property is not supported yet, initial value is leading) or
+        this is the root inline box, the font’s line gap should be taken into account when computing 
+        layout bounds.
+
+        * layout/inlineformatting/InlineFormattingContextGeometry.cpp:
+        (WebCore::Layout::LineBoxBuilder::setVerticalGeometryForInlineBox const):
+
 2021-01-30  Wenson Hsieh  <wenson_hsieh@apple.com>
 

trunk/Source/WebCore/layout/inlineformatting/InlineFormattingContextGeometry.cpp

@@ -186 +186 @@
         // If line-height computes to normal and either text-edge is leading or this is the root inline box,
         // the font’s line gap metric may also be incorporated into A and D by adding half to each side as half-leading.
-        auto shouldLineGapStretchInlineLevelBox = inlineLevelBox.isRootInlineBox() || inlineLevelBox.isLineBreakBox();
-        if (shouldLineGapStretchInlineLevelBox) {
-            auto halfLineGap = (fontMetrics.lineSpacing() - logicalHeight) / 2;
-            ascent += halfLineGap;
-            descent += halfLineGap;
-        }
+        // https://www.w3.org/TR/css-inline-3/#inline-height
+        // Since text-edge is not supported yet and the initial value is leading, we should just apply it to
+        // all inline boxes.
+        auto halfLineGap = (fontMetrics.lineSpacing() - logicalHeight) / 2;
+        ascent += halfLineGap;
+        descent += halfLineGap;
     } else {
         InlineLayoutUnit lineHeight = style.computedLineHeight();