Line Breaking Problem of WebKit

、 (U+3001) and subsequent ASCII token should be breakable into two lines.

。 (U+3002) has the same problem as well.

With the current implementation of WebKit, 、 and 。 are not treated as line-breakable characters when 、 or 。 is followed by an ASCII token.

For example, は、ABC is not breakable into two lines although we consider it breakable into は、 and ABC.

In Japanese writing, we use these characters just like comma and period in English. We can break a line after comma or period in English. It's the same situation for 、 and 。 in Japanese.

IE6/7 and Firefox 2/3 implement it correctly. These browsers can break は、ABC into は、 and ABC appropriately.

The original cause of this problem is the Unicode line breaking algorithm standard.

WebKit depends on the ICU's line break iterator. ICU has a very strict implementation of the Unicode line breaking algorithm.

See Problem in Unicode Line Breaking Algorithm for details.

These are good: The following two should look like “good”: These are bad:

Index: WebCore/platform/text/CharacterNames.h
===================================================================
--- WebCore/platform/text/CharacterNames.h	(revision 30353)
+++ WebCore/platform/text/CharacterNames.h	(working copy)
@@ -39,6 +39,8 @@
     const UChar bullet = 0x2022;
     const UChar horizontalEllipsis = 0x2026;
     const UChar ideographicSpace = 0x3000;
+    const UChar ideographicComma = 0x3001;
+    const UChar ideographicFullStop = 0x3002;
     const UChar leftToRightMark = 0x200E;
     const UChar leftToRightEmbed = 0x202A;
     const UChar leftToRightOverride = 0x202D;
Index: WebCore/rendering/break_lines.cpp
===================================================================
--- WebCore/rendering/break_lines.cpp	(revision 30353)
+++ WebCore/rendering/break_lines.cpp	(working copy)
@@ -51,6 +51,8 @@
         case '-':
         case '?':
         case softHyphen:
+        case ideographicComma:
+        case ideographicFullStop:
             return true;
         default:
             return false;

http://bugs.webkit.org/show_bug.cgi?id=17411