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From: vrm@blackwater.cerc.wvu.wvnet.edu (Vasile R. Montan)
Newsgroups: comp.sys.mac.programmer
Subject: How do you make 'offscreen bitmaps'?
Message-ID: <1553@babcock.cerc.wvu.wvnet.edu>
Date: 8 Apr 91 14:15:46 GMT
Sender: news@cerc.wvu.wvnet.edu
Reply-To: un020070@vaxa.wvnet.edu
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Whenever anyone posts a question on comp.sys.mac.programmer about
animation, the customary response is to use 'offscreen bitmaps'.
While I have no problem understanding this technique in theory,
I'm not sure exactly how to implement it in fact.

Exactly what sort of 'offscreen' structure am I drawing into?
Is it the type actually defined as BitMap?  If so, how do I SetPort
to draw in it, since SetPort accepts a GratPtr as its arguement?
Or is it a GrafPort I am drawing into?  If so, how do I tell the
Toolbox that the GrafPort is off screen?

I presume that CopyBits is the preferred way to put the offscreen
drawing on the screen.

--Kurisuto
un020070@vaxa.wvnet.edu