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From: eric@markov.eedsp.gatech.edu (Eric Hyche)
Newsgroups: comp.windows.x
Subject: How do obtain and/or set a grayscale colormap?
Keywords: colormap,grayscale
Message-ID: <1151@eedsp.eedsp.gatech.edu>
Date: 7 Sep 90 19:05:37 GMT
Sender: news@eedsp.eedsp.gatech.edu
Reply-To: eric@markov.eedsp.gatech.edu (Eric Hyche)
Organization: Georgia Institute of Technology
Lines: 18

I am writing an X-Windows application to manipulate grayscale medical 
images. I would like to set the colormap for the window/screen to a grayscale
colormap at the beginning of the application to save time. However, I cannot
seem to set or obtain the grayscale colormap. Here's what I've tried:

1) XCreateColormap() - and then use XAllocColor to set the color cells.
Problem: the colormap returned by XCreateColormap will not let anything
be allocated to it. And yes, I did set AllocAll, not AllocNone.

2) XGetRGBColormaps() - to try to return the standard RGB_GRAY_MAP. Keep 
getting a segmentation error.

Can anyone help or direct me to an example of how this is done?

Eric Hyche
Georgia Tech, School of Electrical Engineering, Atlanta, GA  30332
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