| Re: IDL/Linux color table problems [message #33087] |
Thu, 05 December 2002 00:41 |
Bringfried Stecklum
Messages: 75
Registered: January 1996
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Member |
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Chris wrote:
>
> Can someone point me to some good fixes for dealing with the color
> table problem when running IDL under Linux? (When I load a color table
> into IDL under linux, I only get grey-scaled images unless I grab the
> window - at which time it takes over the color table for the rest of
> the display). FWIW, I'm working with IDL 5.4, on Redhat Linux.
>
> TIA,
>
> Chris
I had the same behaviour since IDL used the DirectColor visual.
Just put "idl.gr_visual: TrueColor" in your .Xdefaults file.
Then it will use TrueColor instead.
regards,
B.St.
--
Bringfried Stecklum
Th"uringer Landessternwarte Tautenburg
Sternwarte 5, D - 07778 Tautenburg, Germany
Phone: +49-36427-863-54, FAX: +49-36427-863-29
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| Re: IDL/Linux color table problems [message #33110 is a reply to message #33087] |
Tue, 03 December 2002 09:22  |
Karl Schultz
Messages: 341
Registered: October 1999
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Senior Member |
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"David Oesch" <oesch@giub.unibe.ch> wrote in message
news:3DECC898.4070306@giub.unibe.ch...
> Try
>
> http://www.rsinc.com/services/output.cfm?tip_id=3318
This tip really only applies to IDL 5.5 on some 24-bit X servers. The OP is
using IDL 5.4 and probably an 8-bit X server.
It is hard to diagnose the problem exactly, but this sounds like the classic
X "technicolor" problem that is common to many color intensive applications
running on 8-bit X servers. There is some discussion of this issue in the
IDL docs. The basic problem arises because multiple X clients are competing
for a limited set of colors in the 256-color X color table (colormap). Here
are a few general suggestions:
- Configure your X server to start in 16-bit or 24-bit mode, if your video
system supports it. If you are running XFree86, try one of the various X
configuator programs that come with your Linux distro.
- Reduce the color requirements of your other clients. This might mean
shutting down some "color hogs" like image editors and viewers.
- Your window manager and desktop gadgets are clients too. Many desktops
have applets that let you set the number of colors your desktop will use up.
In the extreme case, you can perhaps get it down to two - black and white,
as is possible with CDE.
- Reduce the color demands of IDL. See the IDL help items for using color
in the X windows environment.
If you are absolutely stuck on 8-bit and your IDL app needs to display
(nearly) 256 private colors, then it is pretty hard to avoid the flashing
"technicolor" effect. A lot of 8-bit X windows users accept and tolerate
this effect; it has been around for over a decade.
We can get into more detail here, if you like.
Karl
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