Arrangement_on_surface_2/polycurve_bezier.cpp

// Constructing a arrangement of Bezier polycurves.
 
#include <CGAL/config.h>
 
#ifndef CGAL_USE_CORE
 
#include <iostream>
 
int main() {
  std::cout << "Sorry, this example needs CORE ...\n";
  return 0;
}
 
#else
 
#include <CGAL/Arr_polycurve_traits_2.h>
 
#include "arr_Bezier.h"
#include "arr_print.h"
 
using Polycurve_bezier_traits = CGAL::Arr_polycurve_traits_2<Traits>;
using Point = Polycurve_bezier_traits::Point_2;
using X_mono_polycurve = Polycurve_bezier_traits::X_monotone_curve_2;
using Arrangement_2 = CGAL::Arrangement_2<Polycurve_bezier_traits>;
 
using Make_x_monotone_result = std::variant<Point, Bezier_x_monotone_curve>;
 
int main() {
  Polycurve_bezier_traits pc_traits;
  Traits bezier_traits;
 
  auto ctr_xpolycurve = pc_traits.construct_x_monotone_curve_2_object();
 
  std::vector<Bezier_x_monotone_curve> x_bezier_curves;
 
  // Get the name of the input file from the command line, or use the default
  // Bezier.dat file if no command-line parameters are given.
  const char* filename = "Bezier_polycurve.dat";
 
  // Open the input file.
  std::ifstream in_file(filename);
 
  if (! in_file.is_open()) {
    std::cerr << "Failed to open " << filename << std::endl;
    return 1;
  }
 
  // Read the curves from the input file.
  unsigned int n_curves;
  std::list<Bezier_x_monotone_curve> x_curves;
  Bezier_curve B;
 
  in_file >> n_curves;
  for (size_t k = 0; k < n_curves; ++k) {
    // Read the current curve (specified by its control points).
    in_file >> B;
    // convert it into x-monotone bezier curve.
    std::vector<Make_x_monotone_result> obj_vector;
    bezier_traits.make_x_monotone_2_object()(B, std::back_inserter(obj_vector));
    auto* x_seg_p = std::get_if<Bezier_x_monotone_curve>(&obj_vector[0]);
    x_curves.push_back(*x_seg_p);
  }
 
  X_mono_polycurve polycurve = ctr_xpolycurve(x_curves.begin(), x_curves.end());
  Arrangement_2 arr;
  insert(arr, polycurve);               // construct the arrangement
  print_arrangement_size(arr);          // print the arrangement size
 
  return 0;
}
 
#endif