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From: Dave.Rosenthal@eng.sun.COM (David Rosenthal)
Newsgroups: comp.windows.x
Subject: Re: Apparent limitation to WM_COLORMAP_WINDOWS?
Message-ID: <9104300406.AA06873@devnull.Eng.Sun.COM>
Date: 30 Apr 91 03:49:43 GMT
Sender: daemon@athena.mit.edu (Mr Background)
Organization: The Internet
Lines: 43

> Assume that we have an application with a subwindow using a different visual
> than its parent (so that the parent cannot have the subwindow's colormap), but
> that we want the subwindow's colormap to be installed whenever the parent has
> the colormap focus (even if the subwindow does not have focus at the time).
> 
> For the confused, this would be useful in some kinds of imaging applications.
> 
> Questions:
> 
> 1.  Is there some way under the current ICCCM to accomplish this?  If so, how?

Sections 4.1.2.8 (page 518 of the Digital Press 2nd Edition) and 4.1.8
(page 527) describe the WM_COLORMAP_WINDOWS property.  Nowhere do they
say anything about Visuals - the mechanism they describe works irrespective
of whether the subwindows have the same Visual as the top-level window.
How did you get the idea that there was a difference?

> 2.  If there is no way to accomplish this, what kind of effort would it take
>     to get this capability added?
> 
The capability you want is already in the ICCCM.

> WM_COLORMAP_WINDOWS is almost there but it appears that the colormap will only
> be installed when the focus is directly on the subwindow.
> 
Section 4.1.8 says:

	The window manager will define some colormap focus policy and,
	whenever the top-level window has the colormap focus,  will
	attempt to maximize the number of colormaps from the head of
	the WM_COLORMAP_WINDOWS list that is installed.

Again,  the ICCCM specifically says that the effect you want is to occur.
How did you get the idea that it would not?  (note that the colormap
focus need not be tied to the input focus - that is a WM policy decision).

> Auxiliary question:  Which window managers, if any, currently support
> WM_COLORMAP_WINDOWS?
> 
Any ICCCM-compliant window manager must implement WM_COLORMAP_WINDOWS.
It is not an optional part of the ICCCM.

	David.