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From: jwhitnell@cup.portal.com (Jerry D Whitnell)
Newsgroups: comp.sys.mac.programmer
Subject: Re: rgn rotation
Message-ID: <34387@cup.portal.com>
Date: 29 Sep 90 20:18:33 GMT
References: <111972@tiger.oxy.edu>
Organization: The Portal System (TM)
Lines: 17

Andrew Sonenblick writes...
|We're seeking a quick method of rgn rotation for our animation application.
|Currently, we are painting the rgn to a bitmap, rotating the map, then
|calling BitMapRgn.  Any better ideas?  We'd like to hear them...

The region format is relativly straight forward.  It is basically a set
of "inversion points", where each inversion point causes all bits below and
to the right to be inverted from their current state.  So rotating to
multiples of 90 degrees should be straight-forward.  Rotating to an
arbitrary angle is more difficult since you have to essentially do a polygon
fill and convert back to the region format.

If you need more information on the region format, let me know and I'll
write a short note on it.

Jerry Whitnell
SuperMac Technology