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authorKim Motoyoshi Kalland <kim.kalland@nokia.com>2010-01-11 14:05:20 (GMT)
committerKim Motoyoshi Kalland <kim.kalland@nokia.com>2010-01-11 14:11:59 (GMT)
commiteb84acd899aee992f5631ee0b9c0d992c8fbbd5a (patch)
treedb0366b881edaabe29800cf5f2cc59baf52ac4f6 /src/opengl
parenta34d372b45d75a32dcc300dbb7f8151e15df4294 (diff)
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Fixed subpixel antialiased text drawing with the GL2 engine.
Fixed bug where drawing subpixel antialiased glyphs on a translucent surface would cause all the pixels in the glyphs' bounding box to become opaque. Task-number: QTBUG-7190 Reviewed-by: Trond
Diffstat (limited to 'src/opengl')
-rw-r--r--src/opengl/gl2paintengineex/qtextureglyphcache_gl.cpp18
1 files changed, 15 insertions, 3 deletions
diff --git a/src/opengl/gl2paintengineex/qtextureglyphcache_gl.cpp b/src/opengl/gl2paintengineex/qtextureglyphcache_gl.cpp
index 4034448..0720170 100644
--- a/src/opengl/gl2paintengineex/qtextureglyphcache_gl.cpp
+++ b/src/opengl/gl2paintengineex/qtextureglyphcache_gl.cpp
@@ -81,7 +81,7 @@ void QGLTextureGlyphCache::createTextureData(int width, int height)
data[i] = 0;
if (m_type == QFontEngineGlyphCache::Raster_RGBMask)
- glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_ALPHA, GL_UNSIGNED_BYTE, &data[0]);
+ glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_ALPHA, GL_UNSIGNED_BYTE, &data[0]);
else
glTexImage2D(GL_TEXTURE_2D, 0, GL_ALPHA, width, height, 0, GL_ALPHA, GL_UNSIGNED_BYTE, &data[0]);
@@ -196,8 +196,20 @@ void QGLTextureGlyphCache::fillTexture(const Coord &c, glyph_t glyph)
for (int x = 0; x < maskWidth; ++x)
src[x] = -src[x]; // convert 0 and 1 into 0 and 255
}
- }
-
+ } else if (mask.format() == QImage::Format_RGB32) {
+ // Make the alpha component equal to the average of the RGB values.
+ // This is needed when drawing sub-pixel antialiased text on translucent targets.
+ for (int y = 0; y < maskHeight; ++y) {
+ quint32 *src = (quint32 *) mask.scanLine(y);
+ for (int x = 0; x < maskWidth; ++x) {
+ uchar r = src[x] >> 16;
+ uchar g = src[x] >> 8;
+ uchar b = src[x];
+ quint32 avg = (quint32(r) + quint32(g) + quint32(b) + 1) / 3; // "+1" for rounding.
+ src[x] = (src[x] & 0x00ffffff) | (avg << 24);
+ }
+ }
+ }
glBindTexture(GL_TEXTURE_2D, m_texture);
if (mask.format() == QImage::Format_RGB32) {