Path: utzoo!utgpu!watmath!att!dptg!ulysses!ucbvax!dewey.soe.berkeley.edu!oster
From: oster@dewey.soe.berkeley.edu (David Phillip Oster)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Rotating Text
Message-ID: <32623@ucbvax.BERKELEY.EDU>
Date: 17 Nov 89 04:28:48 GMT
References: <1007.2562b645@csc.anu.oz>
Sender: usenet@ucbvax.BERKELEY.EDU
Reply-To: oster@dewey.soe.berkeley.edu.UUCP (David Phillip Oster)
Organization: School of Education, UC-Berkeley
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There was a great MacTutor article on running TextEdit() with 90 and 180
degree rotations.  the basic idea is: divide the bitmap into 8x8 pixel
rectangles, then use a tuned assembly language routine to rotate the
rectangles, then use CopyBits() (or a tuned loop) to copy each 8x8
rectangle to its destination.  There are some boundary conditions to watch
out for, but you can definately rotate a 256x256 area many times a
second.