So I was doing my usual periodic poke at the problem of automatic, respectful AAing of pixel art,
And recently began to understand how GMIC's 'anisotropic smoothing' function works. (gmic:
http://gmic.sourceforge.net/)
Aside from mangling the shaped dithering into flat color, I like the result (especially how the subtle line flows are picked up and enhanced.. Anisotropic means the smoothing is not a simple linear smoothing, but responds to image features.).
(fortunately, autodetecting dithering is a relatively easy image-processing problem, which I already have a basic solution to)
Source image:
After processing:
I've suspected for a while now that Auto AA of existing pixel art requires some manual adjustment no matter what you do.. basically because the requirements of different picture elements vary in a fairly complex way.
So looking at something like rendering the result on a new layer then erasing bits that seem problematic. (notably most avenues I've tried are pretty cruel to individual isolated pixels)
This particular method works fairly well for normal size pixel art Huge stuff like GGX sprites don't respond so well, because they have these diagonal lines which move like 15 pixels along one axis before they move one pixel in the other.
Before:
After:
FYI, I achieved these result by opening GMIC, selecting Presets->PhotocomiX smoothing, and adjusting the parameters to:
Amplitude 4, sharp 0.3, anisotropic 1, gradsmooth 0,tenssmooth 2,
spatprec .8, angprec 2, valprec 2, nearest neighbour, 3 iterations
Then applying it.
Hmm. I should try it one some of my own works.
Too late at night now, though.
