With word-break: break-all, words do not break correctly before a surrogate pair

https://bugs.webkit.org/show_bug.cgi?id=63401

Reviewed by Darin Adler.

Source/WebCore:

The code to check for mid-word breaks accumulates width one character at a time. It was actually
measuring the two parts of the surrogate pair individually, so they appeared to have zero width.
Fixed by checking for surrogate pairs and measuring the pair as one unit.

Test: fast/text/midword-break-before-surrogate-pair.html

* rendering/RenderBlockLineLayout.cpp:
(WebCore::RenderBlock::LineBreaker::nextLineBreak):

LayoutTests:

* fast/text/midword-break-before-surrogate-pair.html: Added.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@89769 268f45cc-cd09-0410-ab3c-d52691b4dbfc

diff --git a/LayoutTests/ChangeLog b/LayoutTests/ChangeLog
index 702984cef1cdd6e6ac578aeeac97d4b4d15dc2f5..c3f9973434626a51cb4cb58245184f2e0f4020e7 100644 (file)
--- a/LayoutTests/ChangeLog
+++ b/LayoutTests/ChangeLog
@@ -1,3 +1,12 @@
+2011-06-26  Dan Bernstein  <mitz@apple.com>
+
+        Reviewed by Darin Adler.
+
+        With word-break: break-all, words do not break correctly before a surrogate pair
+        https://bugs.webkit.org/show_bug.cgi?id=63401
+
+        * fast/text/midword-break-before-surrogate-pair.html: Added.
+
 2011-06-26  Adam Barth  <abarth@webkit.org>
 
         Note that this test ASSERTs on Linux Debug.

diff --git a/LayoutTests/fast/text/midword-break-before-surrogate-pair.html b/LayoutTests/fast/text/midword-break-before-surrogate-pair.html
new file mode 100644 (file)
index 0000000..b87647a
--- /dev/null
+++ b/LayoutTests/fast/text/midword-break-before-surrogate-pair.html
@@ -0,0 +1,3 @@
+<div style="word-break: break-all; border: solid blue; font-size: 36px; width: 5em;">
+    &#x1d110;&#x1d110;&#x1d110;&#x1d110;&#x1d110;&#x1d110;&#x1d110;&#x1d110;&#x1d110;&#x1d110;
+</div>

diff --git a/LayoutTests/platform/mac/fast/text/midword-break-before-surrogate-pair-expected.png b/LayoutTests/platform/mac/fast/text/midword-break-before-surrogate-pair-expected.png
new file mode 100644 (file)
index 0000000..1c6514d
Binary files /dev/null and b/LayoutTests/platform/mac/fast/text/midword-break-before-surrogate-pair-expected.png differ

diff --git a/LayoutTests/platform/mac/fast/text/midword-break-before-surrogate-pair-expected.txt b/LayoutTests/platform/mac/fast/text/midword-break-before-surrogate-pair-expected.txt
new file mode 100644 (file)
index 0000000..5ca7b73
--- /dev/null
+++ b/LayoutTests/platform/mac/fast/text/midword-break-before-surrogate-pair-expected.txt
@@ -0,0 +1,9 @@
+layer at (0,0) size 800x600
+  RenderView at (0,0) size 800x600
+layer at (0,0) size 800x600
+  RenderBlock {HTML} at (0,0) size 800x600
+    RenderBody {BODY} at (8,8) size 784x584
+      RenderBlock {DIV} at (0,0) size 186x92 [border: (3px solid #0000FF)]
+        RenderText {#text} at (3,3) size 168x84
+          text run at (3,3) width 168: "\x{D834}\x{DD10}\x{D834}\x{DD10}\x{D834}\x{DD10}\x{D834}\x{DD10}\x{D834}\x{DD10}\x{D834}\x{DD10}\x{D834}\x{DD10}"
+          text run at (3,46) width 72: "\x{D834}\x{DD10}\x{D834}\x{DD10}\x{D834}\x{DD10}"

diff --git a/Source/WebCore/ChangeLog b/Source/WebCore/ChangeLog
index f2310751a03b4fa147ac34de7086466b22401e14..8eb564e0c96a454ce28286718d4c5b4abb407f4a 100644 (file)
--- a/Source/WebCore/ChangeLog
+++ b/Source/WebCore/ChangeLog
@@ -1,3 +1,19 @@
+2011-06-26  Dan Bernstein  <mitz@apple.com>
+
+        Reviewed by Darin Adler.
+
+        With word-break: break-all, words do not break correctly before a surrogate pair
+        https://bugs.webkit.org/show_bug.cgi?id=63401
+
+        The code to check for mid-word breaks accumulates width one character at a time. It was actually
+        measuring the two parts of the surrogate pair individually, so they appeared to have zero width.
+        Fixed by checking for surrogate pairs and measuring the pair as one unit.
+
+        Test: fast/text/midword-break-before-surrogate-pair.html
+
+        * rendering/RenderBlockLineLayout.cpp:
+        (WebCore::RenderBlock::LineBreaker::nextLineBreak):
+
 2011-06-26  Dirk Schulze  <krit@webkit.org>
 
         Reviewed by Nikolas Zimmermann.

diff --git a/Source/WebCore/rendering/RenderBlockLineLayout.cpp b/Source/WebCore/rendering/RenderBlockLineLayout.cpp
index 1dadea56ecac809cce4677244456664d17e9615b..76bac49ddda9e7b9d95a0e2846760ba94724ecee 100644 (file)
--- a/Source/WebCore/rendering/RenderBlockLineLayout.cpp
+++ b/Source/WebCore/rendering/RenderBlockLineLayout.cpp
@@ -2102,9 +2102,11 @@ InlineIterator RenderBlock::LineBreaker::nextLineBreak(InlineBidiResolver& resol
 
                 currentCharacterIsWS = currentCharacterIsSpace || (breakNBSP && c == noBreakSpace);
 
+                bool midWordBreakIsBeforeSurrogatePair = false;
                 if ((breakAll || breakWords) && !midWordBreak) {
                     wrapW += charWidth;
-                    charWidth = textWidth(t, current.m_pos, 1, f, width.committedWidth() + wrapW, isFixedPitch, collapseWhiteSpace);
+                    midWordBreakIsBeforeSurrogatePair = U16_IS_LEAD(c) && current.m_pos + 1 < t->textLength() && U16_IS_TRAIL(t->characters()[current.m_pos + 1]);
+                    charWidth = textWidth(t, current.m_pos, midWordBreakIsBeforeSurrogatePair ? 2 : 1, f, width.committedWidth() + wrapW, isFixedPitch, collapseWhiteSpace);
                     midWordBreak = width.committedWidth() + wrapW + charWidth > width.availableWidth();
                 }
 
@@ -2221,6 +2223,8 @@ InlineIterator RenderBlock::LineBreaker::nextLineBreak(InlineBidiResolver& resol
                         // adding the end width forces a break.
                         lBreak.moveTo(current.m_obj, current.m_pos, current.m_nextBreakablePosition);
                         midWordBreak &= (breakWords || breakAll);
+                        if (midWordBreakIsBeforeSurrogatePair)
+                            current.fastIncrementInTextNode();
                     }
 
                     if (betweenWords) {