Partition_2/y_monotone_partition_2.cpp

#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/Partition_traits_2.h>
#include <CGAL/partition_2.h>
#include <cassert>
#include <list>


typedef CGAL::Exact_predicates_inexact_constructions_kernel K;
typedef CGAL::Partition_traits_2<K>                         Traits;
typedef Traits::Point_2                                     Point_2;
typedef Traits::Polygon_2                                   Polygon_2;
typedef std::list<Polygon_2>                                Polygon_list;

void make_polygon(Polygon_2& polygon)
{
   polygon.push_back(Point_2(391, 374));
   polygon.push_back(Point_2(240, 431));
   polygon.push_back(Point_2(252, 340));
   polygon.push_back(Point_2(374, 320));
   polygon.push_back(Point_2(289, 214));
   polygon.push_back(Point_2(134, 390));
   polygon.push_back(Point_2( 68, 186));
   polygon.push_back(Point_2(154, 259));
   polygon.push_back(Point_2(161, 107));
   polygon.push_back(Point_2(435, 108));
   polygon.push_back(Point_2(208, 148));
   polygon.push_back(Point_2(295, 160));
   polygon.push_back(Point_2(421, 212));
   polygon.push_back(Point_2(441, 303));
}


int main( )
{
   Polygon_2    polygon;
   Polygon_list partition_polys;

   make_polygon(polygon);
   CGAL::y_monotone_partition_2(polygon.vertices_begin(),
                                polygon.vertices_end(),
                                std::back_inserter(partition_polys));

   std::list<Polygon_2>::const_iterator   poly_it;
   for (poly_it = partition_polys.begin(); poly_it != partition_polys.end();
        poly_it++)
   {
      assert(CGAL::is_y_monotone_2((*poly_it).vertices_begin(),
                                   (*poly_it).vertices_end()));
   }

   assert(CGAL::partition_is_valid_2(polygon.vertices_begin(),
                                     polygon.vertices_end(),
                                     partition_polys.begin(),
                                     partition_polys.end()));

   return 0;
}