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From: mcintyrd@cs.rpi.edu (David McIntyre)
Newsgroups: comp.windows.x
Subject: Re: Contents of windows
Message-ID: <1438@rpi.edu>
Date: 23 Apr 89 19:56:57 GMT
References: <890422145257.00001135181@grouch.JPL.NASA.GOV>
Sender: usenet@rpi.edu
Organization: Rensselaer Polytechnic Institute, Troy, NY
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Peter Scott writes:
>I just started learning X-Windows, and had assumed that if a window were
>obscured or closed, that X would save its contents and automatically
>restore them when the window or part of window became displayable.  But
>from my reading it appears that redisplay is the responsibility of the
>programmer.  Let me get this straight.  If, for instance, I am writing
>a painting program, then either I have to keep a journal of all the user's
>paint commands, and replay them whenever I am redisplayed, or I have to
>save the bitmap for the window each time the window is modified, and
>restore from that if I am obscured?  

Yes, that is correct.  Redisplaying damaged window contents is the
problem of the client program.

>Suppose I have backing store supported and enabled.  Does X automatically
>restore the contents of the window in this case?

Yes, that takes care of the problem.  Backing store keeps the current
contents of the window, and will re-expose damaged portions.

Dave "mr question" McIntyre     |      "....say you're thinking about a plate
mcintyre@turing.cs.rpi.edu      |       of shrimp.....and someone says to 
office : 518-276-8633		|	you `plate,' or `shrimp'......"
home   : 518-271-6664		|