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From: keithd@cadovax.UUCP (Keith Doyle)
Newsgroups: net.graphics
Subject: Re: Circle Algorithm?
Message-ID: <1009@cadovax.UUCP>
Date: Wed, 5-Feb-86 12:55:25 EST
Article-I.D.: cadovax.1009
Posted: Wed Feb  5 12:55:25 1986
Date-Received: Sun, 9-Feb-86 04:34:18 EST
References: <8300031@uiucdcsb>
Reply-To: keithd@cadovax.UUCP (Keith Doyle)
Organization: CONTEL CADO Systems, Torrance, CA
Lines: 32

In article <8300031@uiucdcsb> robison@uiucdcsb.CS.UIUC.EDU writes:
>
>Within the last 10 years I saw a paper on a circle drawing algorithm
>which was similar to Bresenham's, but drew more accurate circles.   
>It was based on drawing contour lines for a paraboloid.
>I think the article was in one of the IEEE magazines.
>I couldn't find it in the abstracts.  Maybe someone on the net remembers?
>- Arch Robison
>
It was in IEEE CG&A (Computer Graphics & Applications) September 1984.
The article was entitled `An efficient ellipse drawing algorithm' by
Jerry R. Van Aken of Texas Instruments, Inc.  I found the article
very informative, it explains that in some cases the original Bresenham's
can be 1/2 pixel off, and how to correct with the new algorithm, very
similar to Bresenhams, but with a very slight modification.  The algorithm
is illustrated in Pascal, and is only very slightly different than the
original Bresenhams.  I've implemented it on a couple of graphics devices,
and find it works excellently.

You can contact Jerry R. Van Aken directly (according to the article, and
as of Sept. 1984) at:

Jerry R. Van Aken
Texas Instruments, inc
Mail Station 6412
P.O. box 1443
Houston, TX 77001

Keith Doyle
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