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

["Liam Gumley" <Liam.Gumley(at)ssec.wisc.edu>]

Rick Towler <rtowler@u.washington.edu> wrote in message
3904E168.317ACDB1@u.washington.edu">news:3904E168.317ACDB1@u.washington.edu...
> This is really an X windows issue.  I am no expert but I lived with this
> same problem for a long while.
>
> >I tried using hardware and software rendering (by using
> >obj_new('IDLgrWindow',renderer= )), but both came up yellow (and perhaps
> >I can't use hardware rendering, although I have Mesa installed, and I
> >have an NVidia TNT card).
>
> This will have no effect since all images are *rendered* on your solaris
> X client and then displayed on your local linux X server.  So for every
> "frame" sent to you, every pixel in that frame is sent too.
>
> Your problem lies in the fact that your solaris display is running at 16
> bit and your linux display is at 24 bits.  Solaris sends over an 16 bit
> pixel with a that maps incorrectly in you linux X server's 24 bit color
> table.  This is why it works on the 16 bit solaris display and not your
> 24 bit linux display.
>
> Easiest solution is to run your linux desktop at 16bbp.  If I understood
> you correctly, your Solaris hardware is running at 16bpp and running
> both client and server at the same depth should solve your problem.
>
> You may be able to run your solaris box at 24bpp.  This should solve
> your problem too.
>
> Lastly, if your output is static, send it to a .jpg or .gif file and
> view it with a local image viewer (like ee or xv).  This is a minor pain
> but it works.
>
> If none of these solutions work for you take a look at the many X
> Windows How-To's  (http://www.linuxdoc.org/) I'm sure there you'll find
> a better explanation of your problem and will surely find a better
> solution.

I'm not a Linux expert by any means, but this advice goes against my
understanding of how X-windows works. I think the display configuration of
the remote Sun Solaris box has very little to do with the problem. The
display characteristics detected by IDL on the local Linux box are purely
determined by the X-server running on the Linux box. Therefore I would
suspect the X-server on the Linux box before anything else (perhaps an
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.

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

Cheers,
Liam.
PS Linux experts are welcome to enlighten me on this subject.