Changeset 129284 in webkit

Timestamp:

Sep 21, 2012, 6:00:01 PM (12 years ago)

Author:

mitz@apple.com

Message:

REGRESSION (r129176): Incorrect line breaking when kerning occurs between a space and the following character
​https://bugs.webkit.org/show_bug.cgi?id=97377

Reviewed by Enrica Casucci.

Source/WebCore:

Test: fast/text/kerning-with-TextLayout.html

When kerning is enabled, the last character in a word may have its advance shortened because
of its trailing space. To account for that, words are measured along with the trailing space,
then the width of a space is subtracted from the result. This doesn’t work when the trailing
space itself has its advance shortened due to the character following it, which can happen
when using the TextLayout optimization. However, when the optimization is used, the advance
of the last character of the word is already adjusted for the trailing space, so there is no
need to measure with that space and subtract its advance.

• rendering/RenderBlockLineLayout.cpp:

(WebCore::RenderBlock::LineBreaker::nextLineBreak): Changed to not use the trailingSpaceWidth
mechanism when TextLayout is being used.

LayoutTests:

• fast/text/kerning-with-TextLayout-expected.html: Added.
• fast/text/kerning-with-TextLayout.html: Added.

Location:

trunk

Files:

• LayoutTests/ChangeLog (modified) (1 diff)
• LayoutTests/fast/text/kerning-with-TextLayout-expected.html (added)
• LayoutTests/fast/text/kerning-with-TextLayout.html (added)
• Source/WebCore/ChangeLog (modified) (1 diff)
• Source/WebCore/rendering/RenderBlockLineLayout.cpp (modified) (2 diffs)

trunk/LayoutTests/ChangeLog

@@ +1 @@
+2012-09-21  Dan Bernstein  <mitz@apple.com>
+
+        REGRESSION (r129176): Incorrect line breaking when kerning occurs between a space and the following character
+        https://bugs.webkit.org/show_bug.cgi?id=97377
+
+        Reviewed by Enrica Casucci.
+
+        * fast/text/kerning-with-TextLayout-expected.html: Added.
+        * fast/text/kerning-with-TextLayout.html: Added.
+
 2012-09-21  Gavin Barraclough  <barraclough@apple.com>
 

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2012-09-21  Dan Bernstein  <mitz@apple.com>
+
+        REGRESSION (r129176): Incorrect line breaking when kerning occurs between a space and the following character
+        https://bugs.webkit.org/show_bug.cgi?id=97377
+
+        Reviewed by Enrica Casucci.
+
+        Test: fast/text/kerning-with-TextLayout.html
+
+        When kerning is enabled, the last character in a word may have its advance shortened because
+        of its trailing space. To account for that, words are measured along with the trailing space,
+        then the width of a space is subtracted from the result. This doesn’t work when the trailing
+        space itself has its advance shortened due to the character following it, which can happen
+        when using the TextLayout optimization. However, when the optimization is used, the advance
+        of the last character of the word is already adjusted for the trailing space, so there is no
+        need to measure with that space and subtract its advance.
+
+        * rendering/RenderBlockLineLayout.cpp:
+        (WebCore::RenderBlock::LineBreaker::nextLineBreak): Changed to not use the trailingSpaceWidth
+        mechanism when TextLayout is being used.
+
 2012-09-21  Adam Klein  <adamk@chromium.org>
 

trunk/Source/WebCore/rendering/RenderBlockLineLayout.cpp

@@ -2415 +2415 @@
             float lastSpaceWordSpacing = 0;
 
-            // Non-zero only when kerning is enabled, in which case we measure words with their trailing
-            // space, then subtract its width.
-            float wordTrailingSpaceWidth = f.typesettingFeatures() & Kerning ? f.width(constructTextRun(t, f, &space, 1, style)) + wordSpacing : 0;
-
             float wrapW = width.uncommittedWidth() + inlineLogicalWidth(current.m_obj, !appliedStartWidth, true);
             float charWidth = 0;
@@ -2447 +2443 @@
 
             TextLayout* textLayout = renderTextInfo.m_layout.get();
+
+            // Non-zero only when kerning is enabled and TextLayout isn't used, in which case we measure
+            // words with their trailing space, then subtract its width.
+            float wordTrailingSpaceWidth = (f.typesettingFeatures() & Kerning) && !textLayout ? f.width(constructTextRun(t, f, &space, 1, style)) + wordSpacing : 0;
 
             for (; current.m_pos < t->textLength(); current.fastIncrementInTextNode()) {