Fix isolated Thai SARA AM handling

Since 5e07a3ac58f93bd5e09715d43b58c20950c2befa Thai text layout is
handled by libthai to special case of the SARA AM. It didn't handle
isolated SARA AM. This patch fixed it and added detailed explaination
on the special case.

The dotted circle should be shown rather than hidden.

Added a test case to verify that with Waree.

Change-Id: I4967715627cbe15f5a3e9ab3e3844420ab541aed
Reviewed-by: Jiang Jiang <jiang.jiang@nokia.com>

1 files changed, 25 insertions, 0 deletions

diff --git a/tests/auto/qtextscriptengine/tst_qtextscriptengine.cpp b/tests/auto/qtextscriptengine/tst_qtextscriptengine.cpp
index 6a1aaad63d..eafbebd80a 100644
--- a/tests/auto/qtextscriptengine/tst_qtextscriptengine.cpp
+++ b/tests/auto/qtextscriptengine/tst_qtextscriptengine.cpp
@@ -111,6 +111,8 @@ private slots:
 
     void mirroredChars_data();
     void mirroredChars();
+
+    void thaiIsolatedSaraAm();
 };
 
 tst_QTextScriptEngine::tst_QTextScriptEngine()
@@ -1239,5 +1241,28 @@ void tst_QTextScriptEngine::mirroredChars()
     }
 }
 
+void tst_QTextScriptEngine::thaiIsolatedSaraAm()
+{
+    if (QFontDatabase().families(QFontDatabase::Any).contains("Waree")) {
+        QString s;
+        s.append(QChar(0x0e33));
+
+        QTextLayout layout(s, QFont("Waree"));
+        layout.beginLayout();
+        layout.createLine();
+        layout.endLayout();
+
+        QTextEngine *e = layout.engine();
+        e->itemize();
+        e->shape(0);
+
+        QCOMPARE(e->layoutData->items[0].num_glyphs, ushort(3));
+
+        unsigned short *logClusters = e->layoutData->logClustersPtr;
+        QCOMPARE(logClusters[0], ushort(0));
+    } else
+        QSKIP("Cannot find Waree.", SkipAll);
+}
+
 QTEST_MAIN(tst_QTextScriptEngine)
 #include "tst_qtextscriptengine.moc"