Path: utzoo!attcan!uunet!aplcen!samsung!think!husc6!bu-cs!xylogics!world!madd
From: madd@world.std.com (jim frost)
Newsgroups: comp.windows.x
Subject: Re: Colormaps
Message-ID: <1989Nov20.181802.20235@world.std.com>
Date: 20 Nov 89 18:18:02 GMT
References: <5932@cs.yale.edu>
Organization: Software Tool & Die
Lines: 25

gropp-bill@CS.Yale.EDU (Bill Gropp) writes:
>What is the best way to do the following:
>    I have an application that wants to have its own colormap for a window;
>    the colors in this window should be dynamic and defineable by the 
>    application.
[...]
>    When my colormap is installed by the window manager, I'd like the
>    least damage done to other applications.

Since later in your note you say you're using XAllocColor, I assume
"dynamic" doesn't mean "read/write".  With that in mind, the
more-or-less standard way to do this is to do XAllocColor calls on
DefaultColormap().  If the allocation fails, use
XCopyColormapAndFree() to get a new colormap, after which it's pretty
likely that some other applications' colors will be reused.  Most of
the time it works great.

This is fairly standard and is what I do for everything except image
processing, where you have to allocate lots of writable colors.
Should work fine for your application.  Sample code abounds in the
contrib directory.

jim frost
software tool & die
madd@std.com