Re: [Freeciv-Dev] Tiles graphics format (xpm)

[Matt Busigin <jediknight@xxxxxxxxx>]

On Wed, 3 Mar 1999, Greg Wooledge wrote:

#GIFs are compressed using LZW compression, which is covered by a patent in
#the United States.  It is therefore illegal (in the USA) to write software
#which creates GIF images, unless a license is obtained from the patent
#holder (Unisys, I think).  I don't know what the situation is in other
#countries.

It is also illegal Canada.  Software patents seriously suck.

#As far as I know, it is OK to write software which *reads* GIFs, to convert
#or display them -- but not to write them.

AFAIK, also correct.

#PNG (portable network graphics, right?) is supposed to become a GIF
#replacement.  It's a lossless image format (unlike jpeg, which is a great
#format, but lossy), and not subject to the patent problems of GIF.
#Unfortunately, it hasn't caught on.

The JPEG image format, if saved at 100% quality is lossless, I think.  The
loss is in the number of colours the image has, and is used for photographs,
etc.  It isn't a very good choice for pluginable small icons, where the
difference between a few colours might trash the way things look, and
view-ability.  The lossy format is a feature.

#GIFs also offer no significant advantage over XPMs, except for file size.
#GIFs are limited to 256 colors, and unlike XPMs, they can't easily be
#treated like source code (readable patches generated).  Remember, XPMs are
#ASCII text files, so diff/patch work great with them.

Also, XPM is an X/UNIX standard.  Its the right thing to do (tm).

#I'd vote to stay with XPM.

Me too (tm).

                        cheers,
                                matt

Matt Busigin [Perl/Tcl/Sh/C/C++/Lex/Yacc/HTML UNIX Programmer] 
      Member of Geeks Anonymous - http://geeksanon.ab.ca
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