Fix text position with OpenGL engine and Freetype

If you use the OpenGL engine, the left bearing of
the glyph was incorrectly retrieved from the system
as the glyph was queried with the wrong format, and
adjustments for antialiasing were not applied. To
make the position identical to painting with, new
API was added to QFontEngine (The bounding box of
a glyph is also not logically necessarily the same
thing as the bounding box of the rasterized glyph.)

Done-with: Trond
Task-number: QTBUG-14410

1 files changed, 13 insertions, 0 deletions

diff --git a/src/gui/text/qfontengine_p.h b/src/gui/text/qfontengine_p.h
index d07c8c9..d1ec4c1 100644
--- a/src/gui/text/qfontengine_p.h
+++ b/src/gui/text/qfontengine_p.h
@@ -120,6 +120,14 @@ public:
         TestFontEngine = 0x1000
     };
 
+    enum GlyphFormat {
+        Format_None,
+        Format_Render = Format_None,
+        Format_Mono,
+        Format_A8,
+        Format_A32
+    };
+
     QFontEngine();
     virtual ~QFontEngine();
 
@@ -191,6 +199,11 @@ public:
     virtual QImage alphaMapForGlyph(glyph_t, const QTransform &t);
     virtual QImage alphaRGBMapForGlyph(glyph_t, QFixed subPixelPosition, int margin, const QTransform &t);
 
+    virtual glyph_metrics_t alphaMapBoundingBox(glyph_t glyph, const QTransform &matrix, GlyphFormat /*format*/)
+    {
+        return boundingBox(glyph, matrix);
+    }
+
     virtual void removeGlyphFromCache(glyph_t);
 
     virtual glyph_metrics_t boundingBox(const QGlyphLayout &glyphs) = 0;