Bomb Bloke, on 13 May 2017 - 02:04 AM, said:
Did you maybe get the images mixed up? 0.2.0's non-paletted output is apparently showing lots more out-of-place blue / green pixels than 0.1.1's did?
They are not out of place, they're the best approximation of the given color. That's how error diffusion works - notice that the original color, more visible in the paletted output, is a little bit bluish. Applying heavy blur shows the same thing,
like so. You can use --dither-level 0.7 or so to decrease that effect, however, like so:
You can also use the newly introduced ordered dither, because - due to a different algorithm - they do not propagate error in the same way error diffusion does, and as such avoid this side-effect. They also use a pattern for dithering, but at this time it is unfortunately not implemented as well as error diffusion, like so:
However, when the palette is closer to the original image, the ordered dithering algorithm shows results which are not far off in terms of quality from error diffusion, like so:
Edited by asie, 13 May 2017 - 05:55 AM.