[Freeciv-Dev] (PR#5101) improved dithering, made elegant

["Guest" <rt-guest@xxxxxxxxxxxxxx>]

Some of you may remember this one from a while back, but it's gotten
much more elegant and cross-gui-able.

This patch allows rotating dithers for more variety, and over-generous
dithers for mountains, hills, an oceans.  The result is a substancial
visual improvement and an illimination of the embarrising grasslands
(isotrident) or plains (lexxy) that always surrounded the bases of
mountains.

I've tested it in gtk and gtk2.  I've also written it for win32 and mui,
but haven't tested because I don't have those environments.  xaw and sdl
don't use tilesetted dithers, so they are unaffected.

It requires a compatible tileset to have any effect.  I've posted a new
isotrident at http://wam.umd.edu/~dspeyer/isotrident-dither.tgz and a
screenshot at http://wam.umd.edu/~dspeyer/dithershot.jpg (why can't I
upload to ftp.freeciv.org anymore?).

Enjoy!

dither.diff
Description: dither.diff