# [pstricks] cubic b-spline package?

Michael Sharpe msharpe at ucsd.edu
Wed Jun 4 20:24:34 CEST 2008

```Carsten and Herbert,

Thanks for these useful pointers, which are relevant to my question. I
was looking for something a bit different, which I'll spell out a
little more in the uniform case with relaxed endpoints. You are given
B_0, ..., B_n, each B-spline control point B_i a coordinate pair. Let
S_1=(B_0+4*B_1+B_2)/6, and so on up to S_{n-1}. The first part of the
cubic B-spline curve determined by the B_i is the cubic Bezier curve
with control points B_0, (2*B_0+B_1)/3, (B_0+2*B_1)/3, S_1, the second
is the cubic Bezier curve with control points S_1, (2*B_1+B_2)/3,
(B_1+2*B_2)/3, S_2, and so on. (The B-spline curve interpolates B_0,
S_1,...S_{n-1}, B_n, not B_0,...,B_n.)

Michael

On Jun 4, 2008, at 12:00 AM, Herbert Voss wrote:

> Carsten Vogel schrieb:
>> Michael Sharpe schrieb:
>>> Does anyone know of a PSTricks package that would allow one render a
>>> curve determined by a sequence of B-spline control points, as a
>>> sequence of cubic B\'ezier curves? Even the simplest case (uniform,
>>> relaxed) or the uniform, periodic case?
>>>
>>>
>> http://www.tn-home.de/Tobias/Soft/TeX/home.html#PSTricks
>>
>> The package *pst-bezier* provides LaTeX-macros for Bezier splines
>
> why is this package not on CTAN??
>
> pst-func also has a \psBezierX with X=1..9, the number of
> control points
>
> Herbert

```

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