CGAL users discussion list

["Fernando Cacciola" <>]

sinan mutlu wrote:
> Hi,
>
> Is there an example code that finds the "straight skeleton" of a simple
> concave or convex polygon.
It's a subset of the example generating offset polygons since that is based on a 
straight skeleton.
But I guess which subset is a bit unclear, so here is it:

#include<vector>
#include<iterator>
#include<iostream>
#include<iomanip>
#include<string>
#include<boost/shared_ptr.hpp>
#include<CGAL/basic.h>
#include<CGAL/Cartesian.h>
#include<CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include<CGAL/Straight_skeleton_builder_2.h>

typedef CGAL::Exact_predicates_inexact_constructions_kernel Kernel;

typedef Kernel::Point_2 Point_2;

typedef CGAL::Straight_skeleton_2<Kernel> Ss;

typedef CGAL::Straight_skeleton_builder_traits_2<Kernel>      SsBuilderTraits;
typedef CGAL::Straight_skeleton_builder_2<SsBuilderTraits,Ss> SsBuilder;

int main()
{
 // A start-shaped polygon, oriented counter-clockwise as required for outer 
contours.
 Point_2 pts[] = { Point_2(-1,-1)
                 , Point_2(0,-12)
                 , Point_2(1,-1)
                 , Point_2(12,0)
                 , Point_2(1,1)
                 , Point_2(0,12)
                 , Point_2(-1,1)
                 , Point_2(-12,0)
                 } ;

 std::vector<Point_2> star(pts,pts+8);

 SsBuilder ssb ;

 ssb.enter_contour(frame,frame+4);

 boost::shared_ptr<Ss> ss = ssb.construct_skeleton();



FWIW, I'm working on a simplified API, based on simple free functions.
The updated manual will contain much more examples using the simplified API

Best

Fernando Cacciola
GeometryFactory