Fix for font engines that don't support subpixel positioning

Reviewed-by: aavit

1 files changed, 17 insertions, 3 deletions

diff --git a/src/gui/text/qfontengine.cpp b/src/gui/text/qfontengine.cpp
index 816c14ab38..24c466427c 100644
--- a/src/gui/text/qfontengine.cpp
+++ b/src/gui/text/qfontengine.cpp
@@ -605,12 +605,13 @@ void QFontEngine::addGlyphsToPath(glyph_t *glyphs, QFixedPoint *positions, int n
     addBitmapFontToPath(x, y, g, path, flags);
 }
 
-QImage QFontEngine::alphaMapForGlyph(glyph_t glyph, const QTransform &t)
+QImage QFontEngine::alphaMapForGlyph(glyph_t glyph, QFixed /*subPixelPosition*/)
 {
-    return alphaMapForGlyph(glyph, 0, t);
+    // For font engines don't support subpixel positioning
+    return alphaMapForGlyph(glyph);
 }
 
-QImage QFontEngine::alphaMapForGlyph(glyph_t glyph, QFixed /*subPixelPosition*/, const QTransform &t)
+QImage QFontEngine::alphaMapForGlyph(glyph_t glyph, const QTransform &t)
 {
     QImage i = alphaMapForGlyph(glyph);
     if (t.type() > QTransform::TxTranslate)
@@ -620,6 +621,19 @@ QImage QFontEngine::alphaMapForGlyph(glyph_t glyph, QFixed /*subPixelPosition*/,
     return i;
 }
 
+QImage QFontEngine::alphaMapForGlyph(glyph_t glyph, QFixed subPixelPosition, const QTransform &t)
+{
+    if (! supportsSubPixelPositions())
+        return alphaMapForGlyph(glyph, t);
+
+    QImage i = alphaMapForGlyph(glyph, subPixelPosition);
+    if (t.type() > QTransform::TxTranslate)
+        i = i.transformed(t).convertToFormat(QImage::Format_Indexed8);
+    Q_ASSERT(i.depth() <= 8); // To verify that transformed didn't change the format...
+
+    return i;
+}
+
 QImage QFontEngine::alphaRGBMapForGlyph(glyph_t glyph, QFixed /*subPixelPosition*/, int /* margin */, const QTransform &t)
 {
     QImage alphaMask = alphaMapForGlyph(glyph, t);