[GRASS5] Darwin Pre2: PNGDriver

[Glynn Clements]

Glynn Clements wrote:

> > > BTW: What does the PNGDriver do?  Is it optional?
> > 
> > Just a comment here: PNGDriver is a nice replacement for
> > CELL driver. The CELL driver writes into the location, while
> > the PNGdriver directly generates PNG files. However,
> > it is also limited to 8bit (what a pity!).
> 
> I'll look into the possibility of using GD-2.0 (currently beta).

OK; PNGdriver should support true-colour images if built with GD-2.0,
provided that the environment variable GRASS_TRUECOLOR is set to the
value TRUE (the literal string).

The structure of the colour-handling code has changed quite a bit, so
the possibility of incompatibility or other problems exists. OTOH,
PNGdriver now behaves more like XDRIVER.

NB: the configure tests for the GD library have grown exponentially;
GD now has four optional dependencies (PNG, JPEG, freetype and Xpm),
resulting in 16 possible combinations (by default, libgd.so.2 doesn't
have any dependency information, so configure has to check them all).

-- 
Glynn Clements <glynn.clements at virgin.net>