Add Grayscale8 and Alpha8 formats to QImage and drawing

Extend the QImage format with two 8-bit grayscale and alpha formats.
These formats have the advantage over Indexed8 that they have simpler
conversion and can be rendered to by the raster engine.

[ChangeLog][QtGui][QImage] Added support grayscale and alpha 8-bit
formats which can also be rendered to.

Change-Id: I4343c80a92a3dda196aa38d0c3ea251b094fc274
Reviewed-by: Gunnar Sletta <gunnar@sletta.org>

1 files changed, 1 insertions, 7 deletions

diff --git a/src/gui/painting/qtextureglyphcache.cpp b/src/gui/painting/qtextureglyphcache.cpp
index fb8c23835d..b39fb3c0e0 100644
--- a/src/gui/painting/qtextureglyphcache.cpp
+++ b/src/gui/painting/qtextureglyphcache.cpp
@@ -293,13 +293,7 @@ void QImageTextureGlyphCache::createTextureData(int width, int height)
         m_image = QImage(width, height, QImage::Format_Mono);
         break;
     case QFontEngine::Format_A8: {
-        m_image = QImage(width, height, QImage::Format_Indexed8);
-        m_image.fill(0);
-        QVector<QRgb> colors(256);
-        QRgb *it = colors.data();
-        for (int i=0; i<256; ++i, ++it)
-            *it = 0xff000000 | i | (i<<8) | (i<<16);
-        m_image.setColorTable(colors);
+        m_image = QImage(width, height, QImage::Format_Alpha8);
         break;   }
     case QFontEngine::Format_A32:
         m_image = QImage(width, height, QImage::Format_RGB32);