Changeset 268823 in webkit

Timestamp:

Oct 21, 2020, 2:21:22 PM (6 years ago)

Author:

Alan Bujtas

Message:

[LFC][IFC] Apply font line-spacing to <br> inline level box
​https://bugs.webkit.org/show_bug.cgi?id=218043

Reviewed by Antti Koivisto.

The inline level box initiated by <br> should be vertically sized the same way as the root inline box is.
(e.g. <div>root text<br></div> <- line break's inline level box should match the layout bounds of the root inline box).

• layout/inlineformatting/InlineFormattingContextGeometry.cpp:

(WebCore::Layout::LineBoxBuilder::isRootInlineBox const):
(WebCore::Layout::LineBoxBuilder::isRootBox const):
(WebCore::Layout::LineBoxBuilder::setVerticalGeometryForInlineBox const):
(WebCore::Layout::LineBoxBuilder::constructInlineLevelBoxes):

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• layout/inlineformatting/InlineFormattingContextGeometry.cpp (modified) (5 diffs)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2020-10-21  Zalan Bujtas  <zalan@apple.com>
+
+        [LFC][IFC] Apply font line-spacing to <br> inline level box
+        https://bugs.webkit.org/show_bug.cgi?id=218043
+
+        Reviewed by Antti Koivisto.
+
+        The inline level box initiated by <br> should be vertically sized the same way as the root inline box is.
+        (e.g. <div>root text<br></div> <- line break's inline level box should match the layout bounds of the root inline box).
+
+        * layout/inlineformatting/InlineFormattingContextGeometry.cpp:
+        (WebCore::Layout::LineBoxBuilder::isRootInlineBox const):
+        (WebCore::Layout::LineBoxBuilder::isRootBox const):
+        (WebCore::Layout::LineBoxBuilder::setVerticalGeometryForInlineBox const):
+        (WebCore::Layout::LineBoxBuilder::constructInlineLevelBoxes):
+
 2020-10-21  Chris Dumez  <cdumez@apple.com>
 

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

@@ -54 +54 @@
     LayoutState& layoutState() const { return formattingContext().layoutState(); }
 
+    bool isRootInlineBox(const LineBox::InlineLevelBox& inlineLevelBox) const { return &inlineLevelBox.layoutBox() == &rootBox(); }
+    bool isRootBox(const ContainerBox& containerBox) const { return &containerBox == &rootBox(); }
+
 private:
     const InlineFormattingContext& m_inlineFormattingContext;
@@ -178 +181 @@
         // 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 lineSpacing = &inlineLevelBox.layoutBox() == &rootBox() ? fontMetrics.lineSpacing() - logicalHeight : InlineLayoutUnit();
-        ascent += lineSpacing / 2;
-        descent += lineSpacing / 2;
+        auto shouldLineGapStretchInlineLevelBox = isRootInlineBox(inlineLevelBox) || inlineLevelBox.isLineBreakBox();
+        if (shouldLineGapStretchInlineLevelBox) {
+            auto halfLineGap = (fontMetrics.lineSpacing() - logicalHeight) / 2;
+            ascent += halfLineGap;
+            descent += halfLineGap;
+        }
     } else {
         InlineLayoutUnit lineHeight = style.computedLineHeight();
@@ -224 +230 @@
         // nested with a [container start] run.
         auto& firstRun = runs[0];
-        auto& firstRunParentInlineBox = firstRun.layoutBox().parent();
+        auto& firstRunParentLayoutBox = firstRun.layoutBox().parent();
         // If the parent is the formatting root, we can stop here. This is root inline box content, there's no nesting inline box from the previous line(s)
         // unless the inline box closing (container end run) is forced over to the current line.
@@ -230 +236 @@
         // <span>normally the inline box closing forms a continuous content</span>
         // <span>unless it's forced to the next line<br></span>
-        if (&firstRunParentInlineBox == &rootBox() && !firstRun.isContainerEnd())
+        if (isRootBox(firstRunParentLayoutBox) && !firstRun.isContainerEnd())
             return;
-        auto* ancestor = &firstRunParentInlineBox;
+        auto* ancestor = &firstRunParentLayoutBox;
         Vector<const Box*> ancestorsWithoutInlineBoxes;
-        while (ancestor != &rootBox()) {
+        while (!isRootBox(*ancestor)) {
             ancestorsWithoutInlineBoxes.append(ancestor);
             ancestor = &ancestor->parent();
@@ -249 +255 @@
     auto stretchRootInlineBoxIfNeededQuirk = [&] (const auto& layoutBox) {
         auto& parentInlineBox = lineBox.inlineLevelBoxForLayoutBox(layoutBox.parent());
-        if (&parentInlineBox.layoutBox() != &rootBox() || !parentInlineBox.isEmpty())
+        if (!isRootInlineBox(parentInlineBox) || !parentInlineBox.isEmpty())
             return;
         setVerticalGeometryForInlineBox(parentInlineBox);