Re: [R] Bezier to line segments

[Adrian Dușa]

Thanks Greg, I'll take a look on that package as well.
I'm still unsure whether to calculate these splines at each function run,
or to store the coordinates of each spline (curve) and read them when
needed. There are performance issues to take into account, but from my
current tests it seems that calculating the coordinates each time decreases
timing performance.

For the moment I opted to store the values, but if I will find a quick(er)
alternative, will change it at the next version.

This is for a new package called venn (now on CRAN), to which I am going to
send an announcement to r-packages.

Best wishes,
Adrian



On Thu, Jan 7, 2016 at 6:54 PM, Greg Snow <538...@gmail.com> wrote:

> 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 Dușa  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 Dușa 
> 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]]
> >
> > __
> > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
> > https://stat.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> > and provide commented, minimal, self-contained, reproducible code.
>
>
>
> --
> Gregory (Greg) L. Snow Ph.D.
> 538...@gmail.com
>



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

[[alternative HTML version deleted]]

__
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

Re: [R] Bezier to line segments

[Greg Snow]

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 Dușa  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 Dușa  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]]
>
> __
> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.



-- 
Gregory (Greg) L. Snow Ph.D.
538...@gmail.com

__
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

Re: [R] Bezier to line segments

[Adrian Dușa]

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 Dușa  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]]

__
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

[R] Bezier to line segments

[Adrian Dușa]

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]]

__
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.