Optimize QStaticText for space

By caching the results of getGlyphPositions() we can make a code path
in the critical paint engines which is optimal both in space and speed.
The engines where speed is of less importance (pdf engine etc.) which
may need more information, we choose the slower code path of drawText()
which lays out the text again. We should have optimal paths in raster,
vg and GL2 paint engines. The others are less important. Memory
consumption of static text is now 14 bytes per glyph, 8 bytes per item
and a static overhead of 40 bytes per QStaticText object.

1 files changed, 4 insertions, 3 deletions

diff --git a/src/gui/painting/qtextureglyphcache_p.h b/src/gui/painting/qtextureglyphcache_p.h
index d347e61..2f7fc96 100644
--- a/src/gui/painting/qtextureglyphcache_p.h
+++ b/src/gui/painting/qtextureglyphcache_p.h
@@ -76,7 +76,8 @@ class Q_GUI_EXPORT QTextureGlyphCache : public QFontEngineGlyphCache
 {
 public:
     QTextureGlyphCache(QFontEngineGlyphCache::Type type, const QTransform &matrix)
-        : QFontEngineGlyphCache(matrix, type), m_w(0), m_h(0), m_cx(0), m_cy(0) { }
+        : QFontEngineGlyphCache(matrix, type), m_w(0), m_h(0), m_cx(0), m_cy(0), 
+          m_current_fontengine(0) { }
 
     virtual ~QTextureGlyphCache() { }
 
@@ -90,7 +91,7 @@ public:
         int baseLineY;
     };
 
-    void populate(const QTextItemInt &ti,
+    void populate(QFontEngine *fontEngine,
                   const QVarLengthArray<glyph_t> &glyphs,
                   const QVarLengthArray<QFixedPoint> &positions);
 
@@ -113,7 +114,7 @@ public:
     QImage textureMapForGlyph(glyph_t g) const;
 
 protected:
-    const QTextItemInt *m_current_textitem;
+    QFontEngine *m_current_fontengine;
 
     int m_w; // image width
     int m_h; // image height