R help - Jan 2016 - Bezier to line segments

Dear All,

I am interested into transforming Bezier curves (or general splines) to a
series of line segments.
For simplicity, the Bezier curves are either cubic (arches, no inflection
points) or they have at most one inflection point.

The entry parameters are exactly four points (with x and y coordinates):
- start point
- end point
- and two control points to define the curve.

I read a lot about parabolic approximation, and there is also a famous
deCasteljau algorithm.

Before attempting to create my own function, I wonder if something like
this already exists in R (or can easily be adapted to R).

Thanks in advance for any hint,
Adrian

-- 
Adrian Dusa
University of Bucharest
Romanian Social Data Archive
Soseaua Panduri nr.90
050663 Bucharest sector 5
Romania

	[[alternative HTML version deleted]]

I just found the package "bezier".
Trying to find the needle, I missed the haystack...

On Wed, Jan 6, 2016 at 9:56 AM, Adrian Du?a <dusa.adrian at unibuc.ro>
wrote:
> Dear All,
>
> I am interested into transforming Bezier curves (or general splines) to a
> series of line segments.
> For simplicity, the Bezier curves are either cubic (arches, no inflection
> points) or they have at most one inflection point.
>
> The entry parameters are exactly four points (with x and y coordinates):
> - start point
> - end point
> - and two control points to define the curve.
>
> I read a lot about parabolic approximation, and there is also a famous
> deCasteljau algorithm.
>
> Before attempting to create my own function, I wonder if something like
> this already exists in R (or can easily be adapted to R).
>
> Thanks in advance for any hint,
> Adrian
>
> --
> Adrian Dusa
> University of Bucharest
> Romanian Social Data Archive
> Soseaua Panduri nr.90
> 050663 Bucharest sector 5
> Romania
>


-- 
Adrian Dusa
University of Bucharest
Romanian Social Data Archive
Soseaua Panduri nr.90
050663 Bucharest sector 5
Romania

	[[alternative HTML version deleted]]

You may also be interested in the xspline function (graphics package,
so you don't need to install or load anything extra) since you mention
general splines.  These splines can be made similar to Bezier curves
(but not exactly the same).  The function returns a set of coordinates
(when draw=FALSE) that represent line segments for drawing the
approximate curve.

On Wed, Jan 6, 2016 at 6:43 AM, Adrian Du?a <dusa.adrian at unibuc.ro>
wrote:
> I just found the package "bezier".
> Trying to find the needle, I missed the haystack...
>
> On Wed, Jan 6, 2016 at 9:56 AM, Adrian Du?a <dusa.adrian at
unibuc.ro> wrote:
>
>> Dear All,
>>
>> I am interested into transforming Bezier curves (or general splines) to
a
>> series of line segments.
>> For simplicity, the Bezier curves are either cubic (arches, no
inflection
>> points) or they have at most one inflection point.
>>
>> The entry parameters are exactly four points (with x and y
coordinates):
>> - start point
>> - end point
>> - and two control points to define the curve.
>>
>> I read a lot about parabolic approximation, and there is also a famous
>> deCasteljau algorithm.
>>
>> Before attempting to create my own function, I wonder if something like
>> this already exists in R (or can easily be adapted to R).
>>
>> Thanks in advance for any hint,
>> Adrian
>>
>> --
>> Adrian Dusa
>> University of Bucharest
>> Romanian Social Data Archive
>> Soseaua Panduri nr.90
>> 050663 Bucharest sector 5
>> Romania
>>
>
>
>
> --
> Adrian Dusa
> University of Bucharest
> Romanian Social Data Archive
> Soseaua Panduri nr.90
> 050663 Bucharest sector 5
> Romania
>
>         [[alternative HTML version deleted]]
>
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-- 
Gregory (Greg) L. Snow Ph.D.
538280 at gmail.com