CGAL 5.4 - 2D Minkowski Sums
Minkowski_sum_2/exact_offset.cpp
// Computing the exact offset of a polygon.
#include <iostream>
#include <CGAL/config.h>
#ifndef CGAL_USE_CORE
int main()
{
std::cout << "Sorry, this example needs CORE ..." << std::endl;
return 0;
}
#else
#include <fstream>
#include <CGAL/Timer.h>
#include <CGAL/Gps_traits_2.h>
#include <CGAL/offset_polygon_2.h>
#include "arr_conics.h"
typedef CGAL::Polygon_2<Rat_kernel> Polygon_2;
typedef CGAL::Gps_traits_2<Traits> Gps_traits;
typedef Gps_traits::Polygon_with_holes_2 Offset_polygon_with_holes_2;
int main(int argc, char* argv[])
{
// Open the input file and read the input polygon.
const char* filename = (argc > 1) ? argv[1] : "spiked.dat";
std::ifstream in_file(filename);
if (! in_file.is_open()) {
std::cerr << "Failed to open the input file." << std::endl;
return -1;
}
Polygon_2 P;
in_file >> P;
in_file.close();
std::cout << "Read an input polygon with " << P.size() << " vertices."
<< std::endl;
// Compute the offset polygon.
Traits traits;
CGAL::Timer timer;
timer.start();
Offset_polygon_with_holes_2 offset = CGAL::offset_polygon_2(P, 5, traits);
double secs = timer.time();
std::cout << "The offset polygon has " << offset.outer_boundary().size()
<< " vertices, " << offset.number_of_holes() << " holes."
<< std::endl;
std::cout << "Offset computation took " << secs << " seconds." << std::endl;
return 0;
}
#endif