4 files changed, 40 insertions, 5 deletions
diff --git a/src/gui/text/qharfbuzzng.cpp b/src/gui/text/qharfbuzzng.cpp
index b2edfc00a0..6437465da8 100644
--- a/src/gui/text/qharfbuzzng.cpp
+++ b/src/gui/text/qharfbuzzng.cpp
@@ -573,17 +573,27 @@ _hb_qt_font_get_glyph_from_name(hb_font_t * /*font*/, void * /*font_data*/,
 
 
 static hb_user_data_key_t _useDesignMetricsKey;
+static hb_user_data_key_t _ignoreGSUB;
 
 void hb_qt_font_set_use_design_metrics(hb_font_t *font, uint value)
 {
     hb_font_set_user_data(font, &_useDesignMetricsKey, (void *)quintptr(value), NULL, true);
 }
 
+void hb_qt_face_set_ignore_gsub(hb_face_t *face, uint value)
+{
+    hb_face_set_user_data(face, &_ignoreGSUB, (void *)quintptr(value), NULL, true);
+}
+
 uint hb_qt_font_get_use_design_metrics(hb_font_t *font)
 {
     return quintptr(hb_font_get_user_data(font, &_useDesignMetricsKey));
 }
 
+uint hb_qt_face_get_ignore_gsub(hb_face_t *face)
+{
+    return quintptr(hb_face_get_user_data(face, &_ignoreGSUB));
+}
 
 struct _hb_qt_font_funcs_t {
     _hb_qt_font_funcs_t()
@@ -618,11 +628,14 @@ hb_font_funcs_t *hb_qt_get_font_funcs()
 
 
 static hb_blob_t *
-_hb_qt_reference_table(hb_face_t * /*face*/, hb_tag_t tag, void *user_data)
+_hb_qt_reference_table(hb_face_t *face, hb_tag_t tag, void *user_data)
 {
     QFontEngine::FaceData *data = static_cast<QFontEngine::FaceData *>(user_data);
     Q_ASSERT(data);
 
+    if (hb_qt_face_get_ignore_gsub(face) && tag == HB_TAG('G','S','U','B'))
+        return hb_blob_get_empty();
+
     qt_get_font_table_func_t get_font_table = data->get_font_table;
     Q_ASSERT(get_font_table);
 
diff --git a/src/gui/text/qharfbuzzng_p.h b/src/gui/text/qharfbuzzng_p.h
index d5e11e6264..8beadbc72c 100644
--- a/src/gui/text/qharfbuzzng_p.h
+++ b/src/gui/text/qharfbuzzng_p.h
@@ -72,6 +72,9 @@ Q_GUI_EXPORT hb_font_t *hb_qt_font_get_for_engine(QFontEngine *fe);
 Q_GUI_EXPORT void hb_qt_font_set_use_design_metrics(hb_font_t *font, uint value);
 Q_GUI_EXPORT uint hb_qt_font_get_use_design_metrics(hb_font_t *font);
 
+Q_GUI_EXPORT void hb_qt_face_set_ignore_gsub(hb_face_t *font, uint value);
+Q_GUI_EXPORT uint hb_qt_face_get_ignore_gsub(hb_face_t *font);
+
 QT_END_NAMESPACE
 
 #endif // QHARFBUZZNG_P_H
diff --git a/src/gui/text/qtextengine.cpp b/src/gui/text/qtextengine.cpp
index 1c924175e2..7dc8e8fadb 100644
--- a/src/gui/text/qtextengine.cpp
+++ b/src/gui/text/qtextengine.cpp
@@ -1059,7 +1059,7 @@ void QTextEngine::shapeText(int item) const
 
 #ifdef QT_ENABLE_HARFBUZZ_NG
     if (Q_LIKELY(qt_useHarfbuzzNG()))
-        si.num_glyphs = shapeTextWithHarfbuzzNG(si, string, itemLength, fontEngine, itemBoundaries, kerningEnabled);
+        si.num_glyphs = shapeTextWithHarfbuzzNG(si, string, itemLength, fontEngine, itemBoundaries, kerningEnabled, letterSpacing != 0);
     else
 #endif
     si.num_glyphs = shapeTextWithHarfbuzz(si, string, itemLength, fontEngine, itemBoundaries, kerningEnabled);
@@ -1121,7 +1121,13 @@ QT_BEGIN_INCLUDE_NAMESPACE
 
 QT_END_INCLUDE_NAMESPACE
 
-int QTextEngine::shapeTextWithHarfbuzzNG(const QScriptItem &si, const ushort *string, int itemLength, QFontEngine *fontEngine, const QVector<uint> &itemBoundaries, bool kerningEnabled) const
+int QTextEngine::shapeTextWithHarfbuzzNG(const QScriptItem &si,
+                                         const ushort *string,
+                                         int itemLength,
+                                         QFontEngine *fontEngine,
+                                         const QVector<uint> &itemBoundaries,
+                                         bool kerningEnabled,
+                                         bool hasLetterSpacing) const
 {
     uint glyphs_shaped = 0;
 
@@ -1135,7 +1141,8 @@ int QTextEngine::shapeTextWithHarfbuzzNG(const QScriptItem &si, const ushort *st
 
     hb_segment_properties_t props = HB_SEGMENT_PROPERTIES_DEFAULT;
     props.direction = si.analysis.bidiLevel % 2 ? HB_DIRECTION_RTL : HB_DIRECTION_LTR;
-    props.script = hb_qt_script_to_script(QChar::Script(si.analysis.script));
+    QChar::Script script = QChar::Script(si.analysis.script);
+    props.script = hb_qt_script_to_script(script);
     // ### props.language = hb_language_get_default_for_script(props.script);
 
     for (int k = 0; k < itemBoundaries.size(); k += 3) {
@@ -1168,6 +1175,12 @@ int QTextEngine::shapeTextWithHarfbuzzNG(const QScriptItem &si, const ushort *st
             Q_ASSERT(hb_font);
             hb_qt_font_set_use_design_metrics(hb_font, option.useDesignMetrics() ? uint(QFontEngine::DesignMetrics) : 0); // ###
 
+            bool scriptRequiresOpenType = ((script >= QChar::Script_Syriac && script <= QChar::Script_Sinhala)
+                                         || script == QChar::Script_Khmer || script == QChar::Script_Nko);
+            hb_face_t *hb_face = hb_font_get_face(hb_font);
+            Q_ASSERT(hb_face);
+            hb_qt_face_set_ignore_gsub(hb_face, hasLetterSpacing && !scriptRequiresOpenType);
+
             const hb_feature_t features[1] = {
                 { HB_TAG('k','e','r','n'), !!kerningEnabled, 0, uint(-1) }
             };
diff --git a/src/gui/text/qtextengine_p.h b/src/gui/text/qtextengine_p.h
index 39c228fd52..7e507bba2d 100644
--- a/src/gui/text/qtextengine_p.h
+++ b/src/gui/text/qtextengine_p.h
@@ -643,7 +643,13 @@ private:
     void addRequiredBoundaries() const;
     void shapeText(int item) const;
 #ifdef QT_ENABLE_HARFBUZZ_NG
-    int shapeTextWithHarfbuzzNG(const QScriptItem &si, const ushort *string, int itemLength, QFontEngine *fontEngine, const QVector<uint> &itemBoundaries, bool kerningEnabled) const;
+    int shapeTextWithHarfbuzzNG(const QScriptItem &si,
+                                const ushort *string,
+                                int itemLength,
+                                QFontEngine *fontEngine,
+                                const QVector<uint> &itemBoundaries,
+                                bool kerningEnabled,
+                                bool hasLetterSpacing) const;
 #endif
     int shapeTextWithHarfbuzz(const QScriptItem &si, const ushort *string, int itemLength, QFontEngine *fontEngine, const QVector<uint> &itemBoundaries, bool kerningEnabled) const;