[GRASSLIST:3862] Re: number of display colors

[Glynn Clements]

Paul Hasenohr wrote:

> When I start a monitor (d.mon start=x2), I always have only 252 colors
> The message is :
> using default visual which is PseudoColor
> ncolors: 252
> Graphics driver [x2] started
> 
> How can I change this "default visual" to something like TrueColor ?
> Is there a way to increase the ncolors ?
> I am running GRASS 5.0.0pre3 on linux redhat 7.2 and I access to it from 
> windows via eXcursion (an X server)

The default visual and the number of colours are determined by the X
server. This is probably determined by the number of colours available
in Windows, although it's possible that the X server might be using an
8 bits-per-pixel emulation even in a mode with more than 256 colours.

You can obtain a list of all of the available visuals using the
"xdpyinfo" program. If a TrueColor visual is available, you can force
XDRIVER to use it by setting the XDRIVER_TRUECOLOR environment
variable to "TRUE", e.g.

	export XDRIVER_TRUECOLOR=TRUE	# bash
or
	setenv XDRIVER_TRUECOLOR TRUE	# tcsh

However, in order to have more than 252 colours, the X server must
provide a visual with more than 8 planes.

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