I've mentioned I'm doing some bar-code scanning, and grayscale is fine, though
the answer should be the same for color even if its a little more work. So
that's the extent of this inquiry. Also, assume no GPU.
QImage does not support the popular YUV video formats. Foruantely, Y (8-bit
gray) is the only channel I need , and it is exactly width*height, and right up
front at bits(). Reading the documentation, it looks like I should use
scanLine(y) for speed.
Section: GRAY_(Y channel)________________|
y:__0_|__1_|__2_|__3_|__4_|__5_|__6_|__7_|
X:0123401234012340123401234012340123401234
|yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy|uuuuuuuuuuuuuuuuuuuu|vvvvvvvvvvvvvvvvvvvv|
constuchar*bits=frame.bits();
for(inty=0;y<frame.height();y++)
{
QRgb*scanLine=(QRgb*)converted.scanLine(y);
for(intx=0;x<frame.width();x++)
{
intc=bits[y*frame.width()+x];
scanLine[x]=qRgba(c,c,c,255);
}
}
But then I got to thinking maybe a indexed 8 would be better? That way I don't
need to give 4 pixel components (RGBA) I can just give 1 gray value. So when
accessing Indexed-8bit images, is that more work because of the color table
lookups?
Thanks!
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