[Freeciv-Dev] Re: PNG for freeciv

[Raimar Falke <rf13@xxxxxxxxxxxxxxxxx>]

On Thu, Oct 31, 2002 at 05:02:33PM -0500, Jason Dorje Short wrote:
> Currently FreeCiv uses XPM format for its image files (in the tilesets).
> 
> This is disadvantageous for several reasons.  XPM files are uncompressed 
> and substantially larger than PNG (converting all XPMs in the CVS 
> distribution drops the size from 3.6MB to 800kB).  XPM isn't fully 
> portable - the win32 client uses only png (I think) and so to compile it 
> all XPM files must be converted by hand.  No doubt there are more 
> reasons as well.

> Anyway, FreeCiv wants to move to using PNG format.

Yes.

> The main problem here is that XAW is not capable of handling PNG files. 
>  There are several possible ways around this.
> 
> 1.  XAW support could be dropped altogether.  This has been mentioned, 
> but I don't think it's serious.
> 
> 2.  In compilation, the PNG files could be converted to XPMs.  This 
> would require a *compilation* dependency on ImageMagick or another 
> conversion program.  However, it has several drawbacks.  If you install 
> multiple clients, you'll get XPM and PNG files installed.  And if you 
> want to use a modpack you'll have to convert the files to XPM yourself 
> (or the modpack creator will have to provide both, or provide an 
> installation script to do it).
> 
> 3.  In runtime, the png files could be loaded and converted to XPMs. 
> This would require a *runtime* dependency on ImageMagick or another 
> conversion program.  (Note that there could be licence issues here, but 
> I think ImageMagick is safe to use.)  This avoids all disadvantages 
> above.  However, the conversion process is not fast - a demo program I 
> wrote to do the conversion took 23 seconds to load all PNG files from 
> trident/ and misc/.  The runtime library dependency is also a 
> disadvantage, but a small one (ImageMagick, at least, is very common).
> 
> 4.  In runtime, (locally) convert the PNG files to XPMs.  This also 
> requires a *runtime* dependency on ImageMagick or another conversion 
> program.  The difference from above is that the conversion will only be 
> done once (per user) and will be done automatically.  The drawback is 
> that in addition to the globally-installed PNG files there will also be 
> a local copy per user of the XPM version.  Timestamps will have to be 
> checked to see when the PNG file changes.

5. Xaw is teached to use PNG with an external library (libpng or imlib
for example). If this library isn't installed we provide a set of
graphics in XBM on the ftp server. We will see how many want them. In
the best case the set of people is empty.

        Raimar

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