Move advances for control character in Indic syllable shaping

When handling control characters (ZWJ, ZWNJ) in Indic syllables,
we only moved glyphs and attributes of the item, advances should
also be moved forward, otherwise we will use the advance of ZWJ/
ZWNJ for the part of syllable, which is normally zero, it results
some positioning problems.

Task-number: QTBUG-14204
Reviewed-by: Lars Knoll

2 files changed, 18 insertions, 0 deletions

diff --git a/src/3rdparty/harfbuzz/src/harfbuzz-indic.cpp b/src/3rdparty/harfbuzz/src/harfbuzz-indic.cpp
index 237c9ae..b3f9577 100644
--- a/src/3rdparty/harfbuzz/src/harfbuzz-indic.cpp
+++ b/src/3rdparty/harfbuzz/src/harfbuzz-indic.cpp
@@ -1683,6 +1683,7 @@ static bool indic_shape_syllable(HB_Bool openType, HB_ShaperItem *item, bool inv
                 }
                 item->glyphs[j] = item->glyphs[i];
                 item->attributes[j] = item->attributes[i];
+                item->advances[j] = item->advances[i];
                 ++i;
                 ++j;
             }
diff --git a/tests/auto/qtextscriptengine/tst_qtextscriptengine.cpp b/tests/auto/qtextscriptengine/tst_qtextscriptengine.cpp
index 3c26e54..1b3645f 100644
--- a/tests/auto/qtextscriptengine/tst_qtextscriptengine.cpp
+++ b/tests/auto/qtextscriptengine/tst_qtextscriptengine.cpp
@@ -103,6 +103,7 @@ private slots:
 
     void khmer();
     void linearB();
+    void controlInSyllable_qtbug14204();
 };
 
 tst_QTextScriptEngine::tst_QTextScriptEngine()
@@ -1111,6 +1112,22 @@ void tst_QTextScriptEngine::greek()
 #endif
 }
 
+void tst_QTextScriptEngine::controlInSyllable_qtbug14204()
+{
+    QString s;
+    s.append(QChar(0x0915));
+    s.append(QChar(0x094d));
+    s.append(QChar(0x200d));
+    s.append(QChar(0x0915));
+
+    QTextLayout layout(s);
+    QTextEngine *e = layout.d;
+    e->itemize();
+    e->shape(0);
+
+    QVERIFY(e->layoutData->items[0].num_glyphs == 2);
+    QVERIFY(e->layoutData->glyphLayout.advances_x[1] != 0);
+}
 
 QTEST_MAIN(tst_QTextScriptEngine)
 #include "tst_qtextscriptengine.moc"