CGAL 5.3.1 - 2D Minkowski Sums
Minkowski_sum_2/exact_inset.cpp
// Computing the exact inner 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_2 Offset_polygon;
int main(int argc, char* argv[])
{
// Open the input file and read the input polygon.
const char* filename = (argc > 1) ? argv[1] : "tight.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 inner offset of the polygon.
Traits traits;
std::list<Offset_polygon> inset_polygons;
CGAL::Timer timer;
timer.start();
inset_polygon_2(P, 1, traits, std::back_inserter(inset_polygons));
double secs = timer.time();
std::list<Offset_polygon>::iterator it;
std::cout << "The inset comprises "
<< inset_polygons.size() << " polygon(s)." << std::endl;
for (it = inset_polygons.begin(); it != inset_polygons.end(); ++it)
std::cout << " Polygon with " << it->size() << " vertices."
<< std::endl;
std::cout << "Inset computation took " << secs << " seconds." << std::endl;
return 0;
}
#endif