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[Yang Qu <>]

Hi,

I use the attached code to compute difference of a polygon and a polygon 
with holes,
I got the code compiled, but when I run it, it gives me the error: the 
polygon has a wrong orientation

Anyone know why this happened?

Regards,
Yang



#include "CGALTypedefs.hpp"
#include <vector>
#include <CGAL/Boolean_set_operations_2.h>

using namespace std;

int main(int argc, char *argv[]) {
    vector<Point_2> outer_boundary;
    outer_boundary.push_back(Point_2(0, 0));
    outer_boundary.push_back(Point_2(4, 0));
    outer_boundary.push_back(Point_2(4, 4));
    outer_boundary.push_back(Point_2(0, 4));

    vector<Point_2> holePoints;
    holePoints.push_back(Point_2(1, 1));
    holePoints.push_back(Point_2(2, 1));
    holePoints.push_back(Point_2(2, 2));
    holePoints.push_back(Point_2(1, 2));

    vector<Point_2> smallPoints;
    smallPoints.push_back(Point_2(3, 3));
    smallPoints.push_back(Point_2(3.5, 3));
    smallPoints.push_back(Point_2(3.5, 3.5));
    smallPoints.push_back(Point_2(3, 3.5));

    Polygon_2 small(smallPoints.begin(), smallPoints.end());

    vector<Polygon_2> holes;
    Polygon_2 aHole(holePoints.begin(), holePoints.end());
    holes.push_back(aHole);

    Polygon_2 big(outer_boundary.begin(), outer_boundary.end());

    Polygon_with_holes_2 bigWithHole(big, holes.begin(), holes.end());
    
    Pwh_list_2 result;//typedef std::list<Polygon_with_holes_2> Pwh_list_2;

    CGAL::difference(small, bigWithHole, back_inserter(result));
    return 0;
}

#ifndef CGALINIT_H
#define CGALINIT_H

#include <CGAL/Delaunay_triangulation_2.h>
#include <CGAL/Polygon_2.h>
#include <CGAL/Polygon_with_holes_2.h>
#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/Triangulation_vertex_base_with_id_2.h>
#include <CGAL/Point_set_2.h>
#include <CGAL/basic.h>
#include <vector>
#include <list>
//struct Kernel : CGAL::Exact_predicates_inexact_constructions_kernel {};
typedef CGAL::Exact_predicates_inexact_constructions_kernel Kernel;
//typedef CGAL::Delaunay_triangulation_2<Kernel> Delaunay;
typedef CGAL::Point_set_2<Kernel> Point_set_2;
typedef CGAL::Vector_2<Kernel> Vector_2;
typedef Point_set_2::Vertex_handle Vertex_handle;
typedef Kernel::Point_2 Point_2;
typedef Kernel::Segment_2 Segment_2;
typedef CGAL::Polygon_2<Kernel, std::vector<Point_2> > Polygon_2;
typedef CGAL::Polygon_with_holes_2<Kernel, std::vector<Point_2> > 
Polygon_with_holes_2;
typedef std::list<Polygon_with_holes_2> Pwh_list_2;

#endif