Make OpenGL texture glyph cache use the right freetype glyphs

The freetype font engine would fall back to rasterizing glyphs
via QPainterPath in QFontEngine::alphaMapForGlyph() which has
a rather unfortunate implementation.

Change-Id: Ic0b4095b6f17ab33f0602139f0a8fb441dfba0ee
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@digia.com>

1 files changed, 11 insertions, 1 deletions

diff --git a/src/gui/opengl/qopengltextureglyphcache.cpp b/src/gui/opengl/qopengltextureglyphcache.cpp
index 061e8f4166..3b62d1d63a 100644
--- a/src/gui/opengl/qopengltextureglyphcache.cpp
+++ b/src/gui/opengl/qopengltextureglyphcache.cpp
@@ -303,7 +303,17 @@ void QOpenGLTextureGlyphCache::fillTexture(const Coord &c, glyph_t glyph, QFixed
         return;
     }
 
-    QImage mask = textureMapForGlyph(glyph, subPixelPosition);
+    QImage mask;
+
+    if (m_current_fontengine->hasInternalCaching()) {
+        QImage *alphaMap = m_current_fontengine->lockedAlphaMapForGlyph(glyph, subPixelPosition, QFontEngine::Format_None);
+        if (!alphaMap || alphaMap->isNull())
+            return;
+        mask = alphaMap->copy();
+        m_current_fontengine->unlockAlphaMapForGlyph();
+    } else {
+        mask = textureMapForGlyph(glyph, subPixelPosition);
+    }
     const int maskWidth = mask.width();
     const int maskHeight = mask.height();