5 files changed, 52 insertions, 1 deletions
diff --git a/src/platformsupport/fontdatabases/mac/qfontengine_coretext.mm b/src/platformsupport/fontdatabases/mac/qfontengine_coretext.mm
index 732aead62a..be1696dfe8 100644
--- a/src/platformsupport/fontdatabases/mac/qfontengine_coretext.mm
+++ b/src/platformsupport/fontdatabases/mac/qfontengine_coretext.mm
@@ -215,6 +215,8 @@ void QCoreTextFontEngine::init()
     Q_ASSERT((void *)(&ctfont + 1) == (void *)&cgFont);
     faceData.user_data = &ctfont;
     faceData.get_font_table = ct_getSfntTable;
+
+    kerningPairsLoaded = false;
 }
 
 glyph_t QCoreTextFontEngine::glyphIndex(uint ucs4) const
@@ -788,4 +790,17 @@ QFontEngine::Properties QCoreTextFontEngine::properties() const
     return result;
 }
 
+void QCoreTextFontEngine::doKerning(QGlyphLayout *g, ShaperFlags flags) const
+{
+    if (!kerningPairsLoaded) {
+        kerningPairsLoaded = true;
+        qreal emSquare = CTFontGetUnitsPerEm(ctfont);
+        qreal scale = emSquare / CTFontGetSize(ctfont);
+
+        const_cast<QCoreTextFontEngine *>(this)->loadKerningPairs(QFixed::fromReal(scale));
+    }
+
+    QFontEngine::doKerning(g, flags);
+}
+
 QT_END_NAMESPACE
diff --git a/src/platformsupport/fontdatabases/mac/qfontengine_coretext_p.h b/src/platformsupport/fontdatabases/mac/qfontengine_coretext_p.h
index 1c33ae7d84..c22d1ddc0a 100644
--- a/src/platformsupport/fontdatabases/mac/qfontengine_coretext_p.h
+++ b/src/platformsupport/fontdatabases/mac/qfontengine_coretext_p.h
@@ -97,6 +97,7 @@ public:
     glyph_metrics_t alphaMapBoundingBox(glyph_t glyph, QFixed, const QTransform &matrix, GlyphFormat) Q_DECL_OVERRIDE;
     QImage bitmapForGlyph(glyph_t, QFixed subPixelPosition, const QTransform &t) Q_DECL_OVERRIDE;
     QFixed emSquareSize() const Q_DECL_OVERRIDE;
+    void doKerning(QGlyphLayout *g, ShaperFlags flags) const Q_DECL_OVERRIDE;
 
     bool supportsTransformation(const QTransform &transform) const Q_DECL_OVERRIDE;
 
@@ -134,6 +135,7 @@ private:
     CGAffineTransform transform;
     QFixed avgCharWidth;
     QFontEngine::FaceId face_id;
+    mutable bool kerningPairsLoaded;
 };
 
 CGAffineTransform qt_transform_from_fontdef(const QFontDef &fontDef);
diff --git a/src/plugins/platforms/windows/qwindowsfontengine.cpp b/src/plugins/platforms/windows/qwindowsfontengine.cpp
index ca3e2527e9..b6bc65055f 100644
--- a/src/plugins/platforms/windows/qwindowsfontengine.cpp
+++ b/src/plugins/platforms/windows/qwindowsfontengine.cpp
@@ -197,7 +197,7 @@ void QWindowsFontEngine::getCMap()
         designToDevice = QFixed((int)otm->otmEMSquare)/QFixed::fromReal(fontDef.pixelSize);
         unitsPerEm = otm->otmEMSquare;
         x_height = (int)otm->otmsXHeight;
-        loadKerningPairs(QFixed((int)otm->otmEMSquare)/int(otm->otmTextMetrics.tmHeight));
+        loadKerningPairs(designToDevice);
         _faceId.filename = QFile::encodeName(QString::fromWCharArray((wchar_t *)((char *)otm + (quintptr)otm->otmpFullName)));
         lineWidth = otm->otmsUnderscoreSize;
         fsType = otm->otmfsType;
diff --git a/tests/auto/gui/text/qrawfont/tst_qrawfont.cpp b/tests/auto/gui/text/qrawfont/tst_qrawfont.cpp
index c12acf65cc..b1e292f094 100644
--- a/tests/auto/gui/text/qrawfont/tst_qrawfont.cpp
+++ b/tests/auto/gui/text/qrawfont/tst_qrawfont.cpp
@@ -93,6 +93,8 @@ private slots:
     void multipleRawFontsFromData();
 
     void rawFontFromInvalidData();
+
+    void kernedAdvances();
 private:
     QString testFont;
     QString testFontBoldItalic;
@@ -954,6 +956,38 @@ void tst_QRawFont::rawFontFromInvalidData()
     QVERIFY(!font.isValid());
 }
 
+#define FUZZY_LTEQ(X, Y) (X < Y || qFuzzyCompare(X, Y))
+
+void tst_QRawFont::kernedAdvances()
+{
+    const int emSquareSize = 1000;
+    const qreal pixelSize = 16.0;
+    const int underScoreAW = 500;
+    const int underscoreTwoKerning = -500;
+    const qreal errorMargin = 1.0 / 16.0; // Fixed point error margin
+
+    QRawFont font(testFont, pixelSize);
+    QVERIFY(font.isValid());
+
+    QVector<quint32> glyphIndexes = font.glyphIndexesForString(QStringLiteral("__"));
+    QCOMPARE(glyphIndexes.size(), 2);
+
+    QVector<QPointF> advances = font.advancesForGlyphIndexes(glyphIndexes, QRawFont::KernedAdvances);
+    QCOMPARE(advances.size(), 2);
+
+    qreal expectedAdvanceWidth = pixelSize * underScoreAW / emSquareSize;
+    QVERIFY(FUZZY_LTEQ(qAbs(advances.at(0).x() - expectedAdvanceWidth), errorMargin));
+
+    glyphIndexes = font.glyphIndexesForString(QStringLiteral("_2"));
+    QCOMPARE(glyphIndexes.size(), 2);
+
+    advances = font.advancesForGlyphIndexes(glyphIndexes, QRawFont::KernedAdvances);
+    QCOMPARE(advances.size(), 2);
+
+    expectedAdvanceWidth = pixelSize * (underScoreAW + underscoreTwoKerning) / emSquareSize;
+    QVERIFY(FUZZY_LTEQ(qAbs(advances.at(0).x() - expectedAdvanceWidth), errorMargin));
+}
+
 #endif // QT_NO_RAWFONT
 
 QTEST_MAIN(tst_QRawFont)
diff --git a/tests/auto/shared/resources/testfont.ttf b/tests/auto/shared/resources/testfont.ttf
index d6042d2e58..93b728c776 100644
--- a/tests/auto/shared/resources/testfont.ttf
+++ b/tests/auto/shared/resources/testfont.ttf