QTextEngine - treat a fullstop (0x2E) as the same script as the preceeding text when dividing up strings

Many languages use a fullstop to indicate an abbreviation, making the
fullstop part of the word.  For languages like thai, it is required to
pass the fullstop along for correct word breaking.

Change-Id: I5ad0ddbc66ea96e08913446dad8fd3c5d5dd0905
Reviewed-by: Lars Knoll <lars.knoll@nokia.com>
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@nokia.com>

1 files changed, 14 insertions, 1 deletions

diff --git a/src/gui/text/qtextengine.cpp b/src/gui/text/qtextengine.cpp
index bc7f4f7ad6..30170759a0 100644
--- a/src/gui/text/qtextengine.cpp
+++ b/src/gui/text/qtextengine.cpp
@@ -115,7 +115,20 @@ private:
             return;
         const int end = start + length;
         for (int i = start + 1; i < end; ++i) {
-            if ((m_analysis[i] == m_analysis[start])
+            // According to the unicode spec we should be treating characters in the Common script
+            // (punctuation, spaces, etc) as being the same script as the surrounding text for the
+            // purpose of splitting up text. This is important because, for example, a fullstop
+            // (0x2E) can be used to indicate an abbreviation and so must be treated as part of a
+            // word.  Thus it must be passed along with the word in languages that have to calculate
+            // word breaks.  For example the thai word "ครม." has no word breaks but the word "ครม"
+            // does.
+            // Unfortuntely because we split up the strings for both wordwrapping and for setting
+            // the font and because Japanese and Chinese are also aliases of the script "Common",
+            // doing this would break too many things.  So instead we only pass the full stop
+            // along, and nothing else.
+            if (m_analysis[i].bidiLevel == m_analysis[start].bidiLevel
+                && m_analysis[i].flags == m_analysis[start].flags
+                && (m_analysis[i].script == m_analysis[start].script || m_string[i] == QLatin1Char('.'))
                 && m_analysis[i].flags < QScriptAnalysis::SpaceTabOrObject
                 && i - start < MaxItemLength)
                 continue;