Old version algorithm was imperfection a bit, quality was poor at some specific
degrees, specifically, when pixel increment pattern on the diagonal lines is
unstable.
This revised version was better than old one even source code is much cleaner
and simpler.
See belows.
*NonAA vs AA:
https://ibb.co/bCNfMc
*Compare the worst case aa in the old version:
https://ibb.co/bEJsZx
*Test video:
https://youtu.be/Wn20Tym5lfg
Evas map supports anti-alias(aa) rendering on sw backened.
When aa is toggled on, map forcely turns alpha channel on while it draws on the surface.
Actually, it was intended to blend polygon edges with destination,
but it breaks one case if the original source image alpha channel were turned off.
Simply, it fixed the issue, new implmentation removes the alpha channel switching,
instead fill the alpha values with 255 when map + aa + alpha_off is drawing on it.
@fix T1975
Hermet Park
ChunEon Park