Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!ukma!tut.cis.ohio-state.edu!bloom-beacon!EXPO.LCS.MIT.EDU!converse
From: converse@EXPO.LCS.MIT.EDU (Donna Converse)
Newsgroups: comp.windows.x
Subject: Re: problem with colormap (X11)
Message-ID: <8910261439.AA16357@expo.lcs.mit.edu>
Date: 26 Oct 89 14:39:04 GMT
References: <1989Oct25.163000.19611@hellgate.utah.edu>
Sender: daemon@bloom-beacon.MIT.EDU
Organization: X Consortium, MIT Laboratory for Computer Science
Lines: 50


> I create a private colormap for a specific window as follows:
> 
>    my_cmap = XCreateColormap(display, win, visual, AllocAll);
>    XSetWindowColormap(dipaly, win, my_cmap);

This notifies the window manager that this window should have your
private colormap installed when the window gets the input focus.
The colormap should be installed immediately, so as a side effect,
if your program has already opened a window on the screen, you may
be able to see the colormap change as your program is running.

However, some R3 window managers ignore your colormap request, and
while running under those particular window managers, you must install
and uninstall the colormap yourself.    When running under window 
managers that do not ignore the colormap request, you must not install
and uninstall the colormap from your application.  

>    for (i = 0; i<64; i++) {
>      Color[i].pixel = i;
>      Color[i].red = ...
>      Color[i].green = ...
>      Color[i].blue = ...
>      ...

You set Color[i].flags = DoRed | DoGreen | DoBlue , don't you?

>    }
>    XStoreColors(display, cmap, Color, 64);

			cmap is the same as my_cmap, right?
> 
> Later in my program, I use 
> 
>   XCreateGC(display, win, ...);
>   XSetForeground(display, gc, Color[i].pixel);
>   XFillRectangle(display, win, gc, ...);
> 
> to form some images.
> 
> It turns out that I always get colors from the default colormap
> instead of the private one. Where did I do wrong??

Other than the questions that I raised, your code looks fine.
If you still have trouble, tell us the server and window manager
that you are using.


Donna Converse
converse@expo.lcs.mit.edu