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From: earleh@eleazar.dartmouth.edu (Earle R. Horton)
Newsgroups: comp.graphics,sci.math,comp.sources.wanted
Subject: Re: looking for a fast ellipse algorithm
Summary: How about arbitrary axes?
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Date: 24 Feb 89 19:31:07 GMT
References: <395@brunix.UUCP> <4070@ingr.com>
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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?

     This is a just a wild guess, but the Macintosh ellipse algorithm
is probably just a hand-optimized variant of one of the algorithms
posted here.  Probably not extremely useful unless your CPU is a
68000-series.

     I would like to see an ellipse algorithm which allows me to
specify the axes of the ellipse as something other than horizontal and
vertical.  Something like this:

                     -           __/
                         -     /  /\
                             -/  / /
                             /  / /-
                             \_/_/      -
                              /	             -
                             /           minor axis
                       major axis

     Anybody got one?



Earle R. Horton. 23 Fletcher Circle, Hanover, NH 03755--Graduate student.
He who puts his hand to the plow and looks back is not fit for the kingdom
of winners.  In any case, 'BACK' doesn't work.