| Re: changing the color map without having to re-load an image [message #29973] |
Wed, 03 April 2002 06:42  |
David Fanning
Messages: 11724
Registered: August 2001
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Senior Member |
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Marc Sauvage (msauvage@cea.fr) writes:
> since I recently changed my work environment from an X-terminal
> running on a solaris network to a mac on OSX with Xfree86, I'm
> experiencing a strange problem with colors: I cannot modify the color
> map (e.g. with xloadct, or by loading a new table with the command
> line) and have these changes apply to the already displayed images.
> The changes will only affect the images I load after the change.
>
> I never experienced this problem in my previous configuration. The
> problem appears to be connected to the way I'm working now: I'm using
> Xdarwin (basically that's Xfree86 compiled form Mac OS X) to start an
> X session on the mac, then I connect to a solaris machine and run IDL
> there on remote.
>
> At first I couldn't even use colors, but searching around made me
> stumble on
>
> device,decompose=0
>
> Which solves this problem. So now I can use colors, any color table,
> in fact. I can modify the color table with xloadct, and I see the
> color table changing in the xloadct widget, but these changes do not
> affect the already opened graphics window and I have to reload the
> images to see the changes (I' ve tried setting retain to 2 but I don't
> think this addresses my problem). This is a pain because in my field,
> astronomy, I have to do this almost all the time to actually see
> what's in the images, and explore the structure of the objects.
>
> I checked on both the Mac and the unix server which types of visual
> were supported (with xpdyinfo) and apparently the same types are
> supported on both side. Currently I'm set to true_color. Also worth
> knowing: my version of IDL is 5.4.
>
> Anyone with ideas on how to solve this problem is welcome.
Welcome to the world of 24-bit color, Marc! :-)
What you are experiencing is perfectly normal, and
exactly they way 24-bit color is suppose to work. And
rest assured, after a bit of an adjustment you are going to
want to work in 24-bit color all the time, just like the
rest of us.
Here are a couple of articles you might want to read:
http://www.dfanning.com/color_tips/identical_graphics.html
http://www.dfanning.com/color_tips/noxloadct.html
Also, download my XCOLORS program and read the documentation
header, especially the information about the NOTIFY_PRO keyword.
http://www.dfanning.com/programs/xcolors.pro
Similar capabilities are built into XLOADCT, but they
are a bit more cumbersome, in my opinion.
Cheers,
David
--
David W. Fanning, Ph.D.
Fanning Software Consulting
Phone: 970-221-0438, E-mail: david@dfanning.com
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Toll-Free IDL Book Orders: 1-888-461-0155
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