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From: lee@TIS.COM (Theodore Lee)
Newsgroups: comp.sys.apple
Subject: Elementary (I assume) Window programming question
Message-ID: <9002161625.AA26906@tj.tis.com>
Date: 16 Feb 90 16:25:35 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
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In my spare time I've been browsing through the toolbox references and
TML examples, gearing myself up for doing some *REAL* programming.
One thought has come to mind -- is there any usual way of updating
windows without completely regenerating them?  Suppose you have a big
window that took a lot of calculating to fill.  A small NDA window gets
opened up and covers up, say, a quarter of the window.  When the NDA
window goes away, moves, or is covered, presumably the main window gets a
window update event.  Rather than redrawing the main window (or even just
that part in the update region) is there a way of saving the pixels that
got covered up by the NDA's window and just restoring them?  (No, I haven't
read all the technotes yet; I suppose, as usual, the answer is in there
somewhere.)  (I was just picking an NDA window as an example; same
question arises in general, e.g., even when just a menu drops down or
when another window gets opened.) Its clear you could have the window
content procedure save a copy of all the pixels in the window when it's
done and use that to redraw (if nothing has changed), but I wondered if
there was any built-in support for that kind of thing that I've missed,
especially something that squirreled away only the pixels in the region
being covered.

lee@TIS.COM