[Freeciv-Dev] Graphics file format

[David Pfitzner <dwp@xxxxxxxxxxxxxx>]

On Mon, 19 Jul 1999 David Pfitzner wrote:

> Since this patch breaks old tiles.xpm, I wonder if this would
> be a good time to split tiles.xpm into terrain.xpm and 
> special.xpm?  (Would this be good?  The latter would be 
> numbers, hit-point bars, etc).  And perhaps also give hills, 
> forests and mountains a full terrain line, rather than just 
> four tiles (no vertical continuity).  (Initially the full line 
> could just be duplications of those four, but it would allow 
> for later improvement).

I would still like to do the above (not sure what to call the
second file? misc.xpm, other.xpm, symbols.xpm?) but I would also
now support breaking tileset compatability even more, and changing
the graphics format to something which has good support for lots 
of colors.

This has generated big discussions a few times before.  My standard
line has been "lets wait till we have a stable release which includes
the Gtk+ client".  Well, we have that now, so what are we waiting
for :-)

The consensus seems to be to use PNG.  I gather that for the Gtk+ 
client, changing to use PNG would be quite easy.  (At least if we 
assume the user's Imlib contains PNG support compiled in?)

For the Xaw client, it seems we have a few options:
1. Require the user have some appropriate library to handle PNG
   (presumably instead of current libXpm requirement).
2. Include code in freeciv to directly support PNG (presumably
   scavanged from some other GPL'd source).
3. Leave the Xaw client using xpm graphics. 

Option 1 means freeciv may not work 'out-of-the-box' on some 
systems where is does now.  How palatable this would be would 
depend on exactly which libs we would require and their portability
etc, which I'm not sure of myself.  

Option 2 is a bit ugly since this does seem to be something
a library should do.  Would depend on how much code is involved.

I would not be too unhappy with option 3, at least in the short 
term, or perhaps as a configure option if configure doesn't find 
appropriate libs for PNG support.  If we did this, I think it 
would be ok to include one 30x30 xpm tileset in the distribution, 
as well as whatever png files we include.  Plus more tilesets in 
both format on the website.  The thing here is that its easy for 
us to convert from full-color png 'source' files to low-color 
xpm files, but not the other way. 

I'd probably still like to do this in two steps though:
  1. split up and re-org tiles.xpm
  2. move to PNG.

Patches to do these are now welcome :-)

Regards,
-- David