2 files changed, 14 insertions, 0 deletions
diff --git a/src/plugins/platforms/windows/qwindowsfontengine.cpp b/src/plugins/platforms/windows/qwindowsfontengine.cpp
index 33ddcaffc5..6b5304120b 100644
--- a/src/plugins/platforms/windows/qwindowsfontengine.cpp
+++ b/src/plugins/platforms/windows/qwindowsfontengine.cpp
@@ -1133,6 +1133,8 @@ QWindowsNativeImage *QWindowsFontEngine::drawGDIGlyph(HFONT font, glyph_t glyph,
                    << "If you need them anyway, start your application with -platform windows:fontengine=freetype.";
    }
 #endif // wince
+
+    // The padding here needs to be kept in sync with the values in alphaMapBoundingBox.
     QWindowsNativeImage *ni = new QWindowsNativeImage(iw + 2 * margin + 4,
                                                       ih + 2 * margin + 4,
                                                       QWindowsNativeImage::systemFormat());
@@ -1167,6 +1169,17 @@ QWindowsNativeImage *QWindowsFontEngine::drawGDIGlyph(HFONT font, glyph_t glyph,
     return ni;
 }
 
+glyph_metrics_t QWindowsFontEngine::alphaMapBoundingBox(glyph_t glyph, QFixed pos, const QTransform &matrix, GlyphFormat format)
+{
+    int margin = 0;
+    if (format == QFontEngine::Format_A32 || format == QFontEngine::Format_ARGB)
+        margin = glyphMargin(QFontEngineGlyphCache::Raster_RGBMask);
+    glyph_metrics_t gm = boundingBox(glyph, matrix);
+    gm.width += margin * 2 + 4;
+    gm.height += margin * 2 + 4;
+    return gm;
+}
+
 QImage QWindowsFontEngine::alphaMapForGlyph(glyph_t glyph, const QTransform &xform)
 {
     HFONT font = hfont;
diff --git a/src/plugins/platforms/windows/qwindowsfontengine.h b/src/plugins/platforms/windows/qwindowsfontengine.h
index 9e92a8fbff..60ff61fcb9 100644
--- a/src/plugins/platforms/windows/qwindowsfontengine.h
+++ b/src/plugins/platforms/windows/qwindowsfontengine.h
@@ -121,6 +121,7 @@ public:
     virtual QImage alphaMapForGlyph(glyph_t t) { return alphaMapForGlyph(t, QTransform()); }
     virtual QImage alphaMapForGlyph(glyph_t, const QTransform &xform);
     virtual QImage alphaRGBMapForGlyph(glyph_t t, QFixed subPixelPosition, const QTransform &xform);
+    virtual glyph_metrics_t alphaMapBoundingBox(glyph_t glyph, QFixed, const QTransform &matrix, GlyphFormat);
 
     virtual QFontEngine *cloneWithSize(qreal pixelSize) const;
     virtual bool supportsTransformation(const QTransform &transform) const;