Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!hplabs!hpfcdc!stroyan
From: stroyan@hpfcdc.HP.COM (Mike Stroyan)
Newsgroups: comp.sys.hp
Subject: Re: X color maps and switching
Message-ID: <5570251@hpfcdc.HP.COM>
Date: 1 Aug 89 23:20:16 GMT
References: <578@mmlai.UUCP>
Organization: HP Ft. Collins, Co.
Lines: 34

> I was using the new X Window Systems' ability to output starbase
> to a window, when I stumbled onto a very interesting thing:  When
> the cursor enters the starbase window, the color maps change just
> like I supposed they would.  Unfortunately, the REST of the screen
> turns a kind of reddish-orange extremely distracting hue.

Unfortunately, this is a feature.  If you are using a Starbase program,
(or Xlib program), that changes all of the colors in its colormap, then
the windows using other colormaps will not look correct.  The X11 server
is doing the best that it can to come up with more colors than it has
resources to produce.  It changes the hardware colormap settings to
the values correct for the colormap focus window, and the colors in
the other windows are forced to change as well.  Since multiple windows
may be meant work together with equivalent colormaps, the X11 server
would be presumptuous to black out the rest of the windows when one
window has its colormap installed.

There are some ways to reduce impact of the colormap problem.

 - Use Starbase without the gopen(,,,INIT) flag and allocate colors
   using the Xlib calls.  This will share the default colormap with
   other X11 clients.  It doesn't work in a device independent way.

 - Use Starbase without the gopen(,,,INIT) flag and allocate colors
   using the Starbase rgb calls.  This will share the installed colormap
   with other X11 clients.  Later changes to the installed colormap
   will change the colors that were used by Starbase.

 - Use the xinitcolormap command in the front of .x11start to set up
   some of the colors in the default colormap to match the Starbase
   INIT colors.  Then those colors will remain the same when a Starbase
   program's window has its colormap installed.

Mike Stroyan, stroyan@hpfcla.hp.com