[GRASSLIST:5735] Re: Displaying rasters on a two bit monitor

[Glynn Clements]

H Bowman wrote:

> I've got grass running on through a monochrome NCD x-terminal (circa
> 1992). Everything I've tried so far works fine, except for displaying
> rasters. They just come back as black, even if the color table is set to
> all white.
> 
> d.mon start=x0 reports:
> using default visual which is StaticGray
> ncolors: 2
> Graphics driver [x0] started
> 
> 
> d.vect, d.sites, d.text, and d.barscale all work as expected, as long as
> I choose a light color.
> 
> But d.rast and friends won't output in any color but black.
> 
> What does seem to work is:
> d.erase color=white
> d.rast -o roads
> 
> but it working in negatives gets confusing very quickly and doesn't work
> all that well......
> 
> any ideas or experience?

The display library always reserves colour zero for NULL, so you will
only have one level of grey for all of the non-NULL values.

It appears that there are a couple of bugs which could affect
the situation; however, I'm not sure whether fixing them would gain
you anything.

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