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From: rws@EXPO.LCS.MIT.EDU (Bob Scheifler)
Newsgroups: comp.windows.x
Subject: Re: Window visibility question
Message-ID: <9005021726.AA11596@expire.lcs.mit.edu>
Date: 2 May 90 17:26:36 GMT
References: <206@trwacs.UUCP>
Sender: daemon@athena.mit.edu (Mr Background)
Organization: The Internet
Lines: 7


    I'm looking for a way to calculate which portions of a window are
    visible and which are obscured.

Set your background to None and do a ClearArea, asking for exposures.
If you want to avoid real exposures during the interim, you'll have
to use GrabServer.