[jitter] 2D convex hull (formerly "Compute and draw a contour")

Thanks a lot Paul, I'm going to look at it precisely, and ask my  
friends about writing externals, too ;-)
Best,
Thierry

----------------------------------------
Thierry Fournier
http://www.thierryfournier.net




Le 10 févr. 08 à 18:55, Paul Hertz a écrit :

> Maybe this 2D algorithm may also be of interest, it is very compact:
>
> http://cm.bell-labs.com/who/clarkson/2dch.c
>
> Also, Joe O'Rourke's computational Geometry in C (which I haven't  
> read) has downloadable source in both C and Java, for 3d and multi- 
> dimensioanl hulls--which prob. means you can use it for 2D easily  
> enough.
>
> http://maven.smith.edu/~orourke/books/compgeom.html
>
> -- Paul
>
>
> On Feb 10, 2008 7:40 AM, Thierry Fournier  
> <thierry at thierryfournier.net> wrote:
> Hello again,
>
> I took the liberty of changing the topic name, now that I put a
> precise name on my question.
>
> Continuing my investigations : the existing "2D convex hull"
> algorithms seem to be Graham-Andrew's and Jarvis. Only Randy Jones
> and Wesley Smith evocated these notions on the forum archives (in
> terms evocating the Graham-Andrew's one), but I didn't find another
> indications.
>
> General description can be read on Wikipedia at
> http://en.wikipedia.org/wiki/Convex_hull
>
> Demo functions (? I cannot open it because it's on Windows) can be
> found at the Computational Geometry Algorithms Library :
> http://www.cgal.org/Manual/3.3/doc_html/cgal_manual/packages.html
> (IV - Convex Hull Algorithms > 2D Convex Hull and Extreme Points)
>
> ... and a C++ code shas been developed in Nov. 2007 by Andy  
> Callaghan at
> http://www.microplop.com/2007/11/coursework-hell-convex-hull.html
>
> Could it be a track for the creation of a specific external - or do
> these algorithms already exist in the Max domain ?
>
> Best
> Thierry
>
> ----------------------------------------
> Thierry Fournier
> http://www.thierryfournier.net
>
>
>
>
> Le 10 févr. 08 à 13:10, Thierry Fournier a écrit :
>
> > Hi,
> >
> > Due to Mathieu C. : the correct name of the operation I'm searching
> > to do is a "convex hull".
> >
> > Best
> > Thierry
> >
> > ----------------------------------------
> > Thierry Fournier
> > http://www.thierryfournier.net
> >
> >
> >
> >
> > Le 10 févr. 08 à 10:52, Thierry Fournier a écrit :
> >
> >> Hi Mattijs,
> >>
> >> As my goal is to draw a sort of plasma surrounding all the shapes
> >> (literally, it's a "snake"), I guess the best would be a curve (or
> >> even a set of lines). An important thing is that I have to fill
> >> it, and not only to produce a linear shape.
> >>
> >> Best,
> >> Thierry
> >>
> >> ----------------------------------------
> >> Thierry Fournier
> >> http://www.thierryfournier.net
> >>
> >>
> >>
> >>
> >> Le 10 févr. 08 à 10:15, Mattijs Kneppers a écrit :
> >>
> >>>
> >>> Hi Thierry,
> >>>
> >>> In what format would you need that contour? A box, an oval, a set
> >>> of lines?
> >>>
> >>> Mattijs
> >>>
> >>> Quote: thierry at thierryfourni wrote on Sat, 09 February 2008 16:04
> >>> ----------------------------------------------------
> >>>> Hello,
> >>>>
> >>>> A new (?) topic and question. Does anybody know if there is an
> >>>> existing method to compute the single curve / contour containing
> >>>> all
> >>>> the objects of a binary image ? I've searched the Examples  
> patches
> >>>> and forum, also the cv.jit helps, but I didn't find it.
> >>>>
> >>>> I put an example image on :
> >>>> http://picasaweb.google.com/thierryfournierparis/Jitter
> >>>>
> >>>> Best,
> >>>>
> >>>> Thierry
> >>>>
> >>>> ----------------------------------------
> >>>> Thierry Fournier
> >>>> http://www.thierryfournier.net
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>> ----------------------------------------------------
> >>>
> >>>
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> >>>
> >>
> >>
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> >
> >
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