- yield int(pixels[i]*255)
- yield 255-int(pixels[i+1]*255)
- yield int(pixels[i+2]*255)
+ r = int(pixels[i]*255)
+ yield 255-r if mask&1 else r
+ g = int(pixels[i+1]*255)
+ yield 255-g if mask&2 else g
+ b = int(pixels[i+2]*255)
+ yield 255-b if mask&4 else b