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From: mouse@LARRY.MCRCIM.MCGILL.EDU (der Mouse)
Newsgroups: comp.windows.x
Subject: Re:  Being sure that a window is unmapped
Message-ID: <9007172346.AA28230@Larry.McRCIM.McGill.EDU>
Date: 17 Jul 90 23:46:53 GMT
Sender: daemon@athena.mit.edu (Mr Background)
Organization: The Internet
Lines: 22

> As I understand it, if a program wants to be *sure* that a window is
> actually visible on the screen after an XMapWindow request, the
> program should block until it gets an Expose (not MapNotify) event
> for that window.

That guarantees only that some part of the window is visible (and not
even that; the server may be maintaining backing-store).  If you want
to find out about visibility, how about selecting for
VisibilityChangeMask and watching for VisibilityNotify events?  That
is, after all, what they're for.

> Is there a similar mechanism for unmapping?  Does an UnmapNotify
> actually guarantee that window is not on the screen or does it just
> mean the server will consider removing it sometime in the future?

The former.  While being mapped does not guarantee that the window is
visible, being unmapped does guarantee that it's not.

					der Mouse

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			new: mouse@larry.mcrcim.mcgill.edu