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From: greg@CITI.UMICH.EDU
Newsgroups: comp.windows.x
Subject: Re: Xv11, PolyArc
Message-ID: <8708172152.AA15905@ATHENA.MIT.EDU>
Date: Mon, 17-Aug-87 17:49:00 EDT
Article-I.D.: ATHENA.8708172152.AA15905
Posted: Mon Aug 17 17:49:00 1987
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I have recently been confronted with the problem of non-aligned ellipses.

In writing an IGES translator, I found that IGES supported conics in any
plane. This meant that a circle or some other conic could show up in any
given orientation, after being transformed to 2-D.

To solve the problem, I converted the IGES conic entity into multiple
3-D bezier splines, by simply transforming the control points, these
became 2-D bezier splines, which were easy to rasterize, or in case of
PostScript I was all done.

If anyone is interested I have written an X11 extension to draw bezier
splines, reply and I'll mail you a copy.

	-greg.