Re: Unsupported X Windows visual???

[dirk(at)uwast.astro.wisc.edu (Dirk Fabian)]

In article <37C184E0.F1B00A6F@ssec.wisc.edu>,
Liam Gumley  <Liam.Gumley@ssec.wisc.edu> wrote:
>Todd David Halter wrote:
>> I am running IDL 5.2.1 on a RedHat Linux 6.0 i86 machine with 24bpp.  When I do a device,decompose=0 I get the following error:
>>   Unsupported X Windows visual (class: PseudoColor, depth: 8).
>>   Substituting default (class: TrueColor, Depth: 24).
>> Any ideas on how I can get it to do depth 8 and not depth 24.
>
>While most name-brand Unix consoles (SGI, Sun, IBM etc.) support IDL
>8-bit PseudoColor while running a 24-bit desktop, Linux does not. At
>least most of the common Linux Xserver packages don't support it (e.g.
>XFree86), although AccleratedX might.
>
>If you *really* want to run IDL in 8-bit PseudoColor mode, you'll need
>to restart your Xserver e.g.
>
>startx -- -bpp 8
>
>Cheers,
>Liam.

Not necessarily.  RedHat comes with a little program called Xwrapper that
starts a new X session under the old.

You can be running in 24bpp in one session and then run

Xwrapper :1 -bpp 8 -query localhost

to start a new session in 8bpp.  Use Cntrl-Alt-F7 and Cntrl-Alt-F8 to
switch between the two sessions.  This prevents any mucking around with
config files and a bit more productivity since you don't have to think "am
i going to need IDL today" before you log in.

Cheers, Dirk