Re: Color question (answer is not device,decomposed=0)

[Troy Carter <tcarter(at)pppl.gov>]

On Mon, 24 Apr 2000, Liam Gumley wrote:

> upgrade to XFree86 version 4 is in order). In addition, I believe that IDL
> does *not* support X displays in 16 bpp mode; it only supports 8-bit or
> 24-bit bpp.

IDL runs fine on a 16 bit display.  I do it every day -- in 5.2, it took a
little trickery (I had to set device,pseudo=8,decomposed=0).  But in 5.3
it starts right up.  Yes I am sure the terminal is 16 bit.  Perhaps IDL
effectively runs in 8 bit mode, so perhaps I don't use the 16 bit
capability, but the point is that I don't have to run in lower color depth
to get idl to work.

> The bottom line:
> (1) If you want to get IDL running and do some work, then re-configure your
> Linux X-server to start in 8 bpp.
> (2) If you want to tinker with the X-server, try an upgrade to XFree86 4.0

I don't think it is necessary to run in 8bpp mode.  24bit mode works
great, I have been using it for 1.5 years (linux workstation running idl
session on solaris box).  I have just run into one issue when trying to
migrate to Object graphics.  I think that instead of giving up on 24-bit
mode I should try to solve the problem and perhaps uncover a bug in IDL or
XFree86...  Who the heck works with 8bit displays anymore anyway!? ;)

About XFree86 4.0, I will certainly be trying that as soon as it is a
little more stable.  I probably will not be adventurous and I will wait
until RedHat packages it (maybe when the rawhide packages stabilize).

About my particular problem, after some very helpful comments from several
people (by e-mail mostly), it seems that the problem is due to byte-order
swapping as the solaris box sends graphics to my x-server.  It only
effects the IDLgrView object -- other objects (plots, axes, text,
polygons) all render with the correct colors.  For this reason, it is
possible that it is a bug in IDL (problems with dithering or with the
Mesa libs have been suggested).  Thanks to everyone who commented on the
problem (Randall, Rick, kschultz).  When it is completely resolved, I will
write again to the news group.

-Troy

-- 
Troy Carter
tcarter@pppl.gov
(609) 243-3145