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From: chas@gtss.gatech.edu (Charles Cleveland)
Newsgroups: comp.graphics,sci.math,comp.sources.wanted
Subject: Re: looking for a fast ellipse algorithm
Message-ID: <339@gtss.gatech.edu>
Date: 24 Feb 89 23:35:44 GMT
References: <395@brunix.UUCP> <4070@ingr.com>
Reply-To: chas@gtss.UUCP (Charles Cleveland)
Organization: Georgia Tech School of Physics
Lines: 26

In article <4070@ingr.com> dan@ingr.com (Dan Webb) writes:
)After skimming through all the replies to the question of a fast ellipse
)algorithm, I have yet to see the algorithm used by the Macintosh, which
)happens to be very fast and mathematically perfect.  Why doesn't anyone
)seem to know what it is?  Is it proprietary?  Apple?
)
)	R. Dan Webb
)	UUNET: uunet!ingr!dan
)	INET: dan@ingr.com

When reading in BYTE, back in the days when it wasn't just a PC-clone
magazine with an occasional crust thrown to the Mac as an alternative
approach, someone claimed that the ellipse algorithm on the Mac was
deficient in that a subsequent area fill on the interior could leak out
to the exterior.  The author stated that he could not understand why, when
other fast algorithms were available without this problem, Apple chose
to use the one they did.

Whether this is true or not (is it?), I have not seen the issue addressed in
the recent discussion of ellipse algorithms and would like to hear about it.

-- 
-  It is better for civilization to be going down the drain than to be  -
-  coming up it.                                        -- Henry Allen  -
Charles Cleveland  Georgia Tech School of Physics  Atlanta, GA 30332-0430
UUCP: ...!gatech!gtss!chas                INTERNET:  chas@gtss.gatech.edu