Changeset 246481 in webkit

Timestamp:

Jun 16, 2019, 1:04:31 PM (7 years ago)

Author:

Alan Bujtas

Message:

[LFC][IFC] Ignore descent when in limited/full quirks mode
​https://bugs.webkit.org/show_bug.cgi?id=198893
<rdar://problem/51780634>

Reviewed by Antti Koivisto.

In limited/full quirks mode, line's descent should be ignored when computing the final line height when

1. the line has baseline aligned content only and
2. these baseline aligned boxes don't have descent.

• layout/inlineformatting/InlineLine.cpp:

(WebCore::Layout::Line::isVisuallyEmpty const):
(WebCore::Layout::Line::close):

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• layout/inlineformatting/InlineLine.cpp (modified) (3 diffs)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2019-06-16  Zalan Bujtas  <zalan@apple.com>
+
+        [LFC][IFC] Ignore descent when in limited/full quirks mode
+        https://bugs.webkit.org/show_bug.cgi?id=198893
+        <rdar://problem/51780634>
+
+        Reviewed by Antti Koivisto.
+
+        In limited/full quirks mode, line's descent should be ignored when computing the final line height when
+        1. the line has baseline aligned content only and
+        2. these baseline aligned boxes don't have descent.
+
+        * layout/inlineformatting/InlineLine.cpp:
+        (WebCore::Layout::Line::isVisuallyEmpty const):
+        (WebCore::Layout::Line::close):
+
 2019-06-16  Zalan Bujtas  <zalan@apple.com>
 

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

@@ -101 +101 @@
         }
 
+        auto hasDescent = false;
+        auto hasNonBaselineAlignedContent = false;
         for (auto& run : m_content->runs()) {
             LayoutUnit logicalTop;
             auto& inlineItem = run->inlineItem;
             auto& layoutBox = inlineItem.layoutBox();
+            auto verticalAlign = inlineItem.style().verticalAlign();
             auto ascent = inlineItem.style().fontMetrics().ascent();
 
-            switch (inlineItem.style().verticalAlign()) {
+            switch (verticalAlign) {
             case VerticalAlign::Baseline:
-                if (inlineItem.isLineBreak() || inlineItem.isText())
+                if (inlineItem.isLineBreak() || inlineItem.isText()) {
                     logicalTop = baselineOffset() - ascent;
-                else if (inlineItem.isContainerStart()) {
+                    hasDescent = hasDescent || !run->isCollapsed;
+                } else if (inlineItem.isContainerStart()) {
                     auto& displayBox = m_layoutState.displayBoxForLayoutBox(layoutBox);
                     logicalTop = baselineOffset() - ascent - displayBox.borderTop() - displayBox.paddingTop().valueOr(0);
+                    hasDescent = hasDescent || (displayBox.horizontalBorder() || (displayBox.horizontalPadding() && displayBox.horizontalPadding().value()));
                 } else if (layoutBox.isInlineBlockBox() && layoutBox.establishesInlineFormattingContext()) {
                     auto& formattingState = downcast<InlineFormattingState>(m_layoutState.establishedFormattingState(layoutBox));
@@ -120 +125 @@
                     auto inlineBlockBaseline = formattingState.lineBoxes().last().baseline();
                     logicalTop = baselineOffset() - inlineBlockBaseline.ascent;
+                    hasDescent = hasDescent || inlineBlockBaseline.descent;
                 } else
                     logicalTop = baselineOffset() - run->logicalRect.height();
@@ -133 +139 @@
                 break;
             }
+            hasNonBaselineAlignedContent = hasNonBaselineAlignedContent || verticalAlign != VerticalAlign::Baseline;
             run->logicalRect.setTop(logicalTop);
+        }
+        // Remove descent when all content is baseline aligned but none of them have descent.
+        if (!m_layoutState.inNoQuirksMode() && !hasNonBaselineAlignedContent && !hasDescent) {
+            m_contentLogicalHeight -= m_baseline.descent;
+            m_baseline.descent = { };
         }
     }