Changeset 271347 in webkit

Timestamp:

Jan 9, 2021 4:31:53 AM (3 years ago)

Author:

Alan Bujtas

Message:

[LFC][IFC] Use the bottom margin edge as the baseline for inline-block when overflow is not visible
​https://bugs.webkit.org/show_bug.cgi?id=220481

Reviewed by Antti Koivisto.

"The baseline of an 'inline-block' is the baseline of its last line box in the normal flow, unless it has either no in-flow line boxes
or if its 'overflow' property has a computed value other than 'visible', in which case the baseline is the bottom margin edge."
​https://www.w3.org/TR/CSS22/visudet.html#leading

• layout/inlineformatting/InlineFormattingContextGeometry.cpp:

(WebCore::Layout::LineBoxBuilder::constructInlineLevelBoxes):

Location:

trunk/Source/WebCore

Files:

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

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2021-01-09  Zalan Bujtas  <zalan@apple.com>
+
+        [LFC][IFC] Use the bottom margin edge as the baseline for inline-block when overflow is not visible
+        https://bugs.webkit.org/show_bug.cgi?id=220481
+
+        Reviewed by Antti Koivisto.
+
+        "The baseline of an 'inline-block' is the baseline of its last line box in the normal flow, unless it has either no in-flow line boxes
+        or if its 'overflow' property has a computed value other than 'visible', in which case the baseline is the bottom margin edge."
+        https://www.w3.org/TR/CSS22/visudet.html#leading
+
+        * layout/inlineformatting/InlineFormattingContextGeometry.cpp:
+        (WebCore::Layout::LineBoxBuilder::constructInlineLevelBoxes):
+
 2021-01-08  Peng Liu  <peng.liu6@apple.com>
 

trunk/Source/WebCore/layout/LayoutState.cpp

@@ -245 +245 @@
 }
 
+bool LayoutState::shouldNotSynthesizeInlineBlockBaseline() const
+{
+    return RuntimeEnabledFeatures::sharedFeatures().layoutFormattingContextIntegrationEnabled();
+}
+
 }
 }

trunk/Source/WebCore/layout/LayoutState.h

@@ -94 +94 @@
     void setIsIntegratedRootBoxFirstChild(bool);
     bool shouldIgnoreTrailingLetterSpacing() const;
+    bool shouldNotSynthesizeInlineBlockBaseline() const;
 
 private:

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

@@ -272 +272 @@
             auto marginBoxHeight = inlineLevelBoxGeometry.marginBoxHeight();
             auto ascent = InlineLayoutUnit { };
-            if (layoutBox.isInlineBlockBox() && layoutBox.establishesInlineFormattingContext()) {
-                auto& formattingState = layoutState().establishedInlineFormattingState(downcast<ContainerBox>(layoutBox));
-                auto& lastLine = formattingState.lines().last();
-                auto inlineBlockBaseline = lastLine.lineBoxLogicalRect().top() + lastLine.baseline();
-                ascent = inlineLevelBoxGeometry.marginBefore() + inlineLevelBoxGeometry.borderTop() + inlineLevelBoxGeometry.paddingTop().valueOr(0) + inlineBlockBaseline;
+            if (layoutState().shouldNotSynthesizeInlineBlockBaseline()) {
+                // Integration codepath constructs replaced boxes for inline-block content.
+                ASSERT(layoutBox.isReplacedBox());
+                ascent = *downcast<ReplacedBox>(layoutBox).baseline();
+            } else if (layoutBox.isInlineBlockBox()) {
+                // The baseline of an 'inline-block' is the baseline of its last line box in the normal flow, unless it has either no in-flow line boxes or
+                // if its 'overflow' property has a computed value other than 'visible', in which case the baseline is the bottom margin edge.
+                auto synthesizeBaseline = !layoutBox.establishesInlineFormattingContext() || !layoutBox.style().isOverflowVisible();
+                if (synthesizeBaseline)
+                    ascent = marginBoxHeight;
+                else {
+                    auto& formattingState = layoutState().establishedInlineFormattingState(downcast<ContainerBox>(layoutBox));
+                    auto& lastLine = formattingState.lines().last();
+                    auto inlineBlockBaseline = lastLine.lineBoxLogicalRect().top() + lastLine.baseline();
+                    ascent = inlineLevelBoxGeometry.marginBefore() + inlineLevelBoxGeometry.borderTop() + inlineLevelBoxGeometry.paddingTop().valueOr(0) + inlineBlockBaseline;
+                }
             } else if (layoutBox.isReplacedBox())
                 ascent = downcast<ReplacedBox>(layoutBox).baseline().valueOr(marginBoxHeight);