Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!usc!apple!apple.com!casseres
From: casseres@apple.com (David Casseres)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Rotating Text
Message-ID: <6301@internal.Apple.COM>
Date: 23 Jan 90 02:12:23 GMT
Sender: usenet@Apple.COM
Organization: Apple Computer, Inc.
Lines: 18
References:<1274@husc6.harvard.edu> <104700070@p.cs.uiuc.edu>

In article <104700070@p.cs.uiuc.edu> gillies@p.cs.uiuc.edu writes:
> I think it's kind of surprising that Quickdraw doesn't have a
> RotateCopyBits call, not even for just 90, 180, and 270 degrees
> rotations.  This is an oversight of mammoth proportion.  Does anyone
> know why?

Not an oversight, really.  It's for the same reason a lot of programming 
languages don't have an exponentiation operator built in:  there are a 
number of ways to do the job, but which one is best depends on the 
circumstances.  Doing simple rotations is rather easy in assembly 
language, but how you optimize depends heavily on things like the exact 
dimensions of your bitmap.  In general, note that QuickDraw provides a 
rather complete set of bitmap _transfer_ facilities (i.e. all the 
different transfer modes) but essentially no bitmap _processing_ 
facilities other than simple pack and unpack operations.

David Casseres
     Exclaimer:  Hey!