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From: dgc@cs.purdue.EDU (Doug Crabill)
Newsgroups: comp.lang.postscript
Subject: Re: Spline data points to Bezier curve
Message-ID: <14931@ector.cs.purdue.edu>
Date: 5 Jun 91 14:59:07 GMT
References: <1991Jun3.095901.3793@desire.wright.edu>
	<14921@ector.cs.purdue.edu>
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Organization: Purdue University
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>    In article <1991Jun3.095901.3793@desire.wright.edu> cse0080@desire.wright.edu writes:
> 
>    >   Help!
>    >
>    >   I need to know how to generate spline curves in PostScript when
>    >   all the data I have on hand is an array of data points that lie on 
>    >   the curve itself.  (IE: no control points for the curveto operator)
[deleted]
> 
>    I had a need for this some time ago and hacked my way to a solution.
>    I knew that InterViews and the idraw editor in particular somehow
>    performed the transformation from spline data to a form PostScript
>    would like.  So I hacked the idraw PostScript prolog till I had a
>    minimum copy of their BSpl function.
[deleted]

Two people have (correctly) pointed out that the BSpl solution I
posted is not a solution to the problem as stated.  The curve
generated by BSpl is guaranteed to contain only the first and last
data points and generally does not contain the intermediate data
points, but passes near them.  I do not have a solution for the
problem as stated.

The behavior matches that of idraw's "splines".  Try creating a spline
in idraw and you will see that only the first and last data points
actually lie on the curve.

Sorry for the confusion.

Doug