text: // Boost.Geometry (aka GGL, Generic Geometry Library)
  // Robustness Test - convex_hull
  
  // Copyright (c) 2012-2015 Barend Gehrels, Amsterdam, the Netherlands.
  
  // Use, modification and distribution is subject to the Boost Software License,
  // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
  // http://www.boost.org/LICENSE_1_0.txt)
  
  #define BOOST_GEOMETRY_REPORT_OVERLAY_ERROR
  #define BOOST_GEOMETRY_NO_BOOST_TEST
  
  #include <sstream>
  #include <fstream>
  
  #include <boost/program_options.hpp>
  #include <boost/random/linear_congruential.hpp>
  #include <boost/random/uniform_int.hpp>
  #include <boost/random/uniform_real.hpp>
  #include <boost/random/variate_generator.hpp>
  #include <boost/timer.hpp>
  
  #include <boost/geometry.hpp>
  #include <boost/geometry/geometries/geometries.hpp>
  #include <boost/geometry/geometries/point_xy.hpp>
  #include <boost/geometry/io/svg/svg_mapper.hpp>
  
  struct settings_type
  {
      bool svg;
      bool wkt;
  
      settings_type()
          : svg(false)
          , wkt(false)
      {}
  };
  
  namespace bg = boost::geometry;
  
  template <typename Geometry1, typename Geometry2>
  void create_svg(std::string const& filename, Geometry1 const& points, Geometry2 const& hull)
  {
      typedef typename boost::geometry::point_type<Geometry1>::type point_type;
  
      boost::geometry::model::box<point_type> box;
      bg::envelope(hull, box);
      bg::buffer(box, box, 1.0);
  
      std::ofstream svg(filename.c_str());
      boost::geometry::svg_mapper<point_type> mapper(svg, 800, 800);
      mapper.add(box);
  
      mapper.map(hull, "opacity:0.8;fill:none;stroke:rgb(255,0,255);stroke-width:4;stroke-dasharray:1,7;stroke-linecap:round");
      mapper.map(points, "fill-opacity:0.5;fill:rgb(0,0,255);", 5);
  }
  
  
  template <typename MultiPoint, typename Generator>
  inline void make_multi_point(MultiPoint& mp, Generator& generator, int pcount)
  {
      typedef typename bg::point_type<MultiPoint>::type point_type;
      typedef typename bg::coordinate_type<MultiPoint>::type coordinate_type;
  
      for(int i = 0; i < pcount; i++)
      {
          coordinate_type x, y;
          x = generator();
          y = generator();
  
          point_type p;
          bg::set<0>(p, x);
          bg::set<1>(p, y);
  
          mp.push_back(p);
      }
  }
  
  template <typename MultiPoint, typename Polygon>
  bool check_hull(MultiPoint const& mp, Polygon const& poly)
  {
      for(typename boost::range_iterator<MultiPoint const>::type it = boost::begin(mp);
          it != boost::end(mp);
          ++it)
      {
          if (! bg::covered_by(*it, poly))
          {
              return false;
          }
      }
      return true;
  }
  
  
  template <typename MultiPoint, typename Generator>
  void test_random_multi_points(MultiPoint& result, int& index,
              Generator& generator,
              int pcount, settings_type const& settings)
  {
      typedef typename bg::point_type<MultiPoint>::type point_type;
  
      MultiPoint mp;
      bg::model::polygon<point_type> hull;
  
      make_multi_point(mp, generator, pcount);
      bg::convex_hull(mp, hull);
      // Check if each point lies in the hull
      bool correct = check_hull(mp, hull);
      if (! correct)
      {
          std::cout << "ERROR! " << std::endl
              << bg::wkt(mp) << std::endl
              << bg::wkt(hull) << std::endl
              << std::endl;
              ;
      }
  
      if (settings.svg || ! correct)
      {
          std::ostringstream out;
          out << "random_mp_" << index++ << "_" << pcount << ".svg";
          create_svg(out.str(), mp, hull);
      }
      if (settings.wkt)
      {
          std::cout
              << "input: " << bg::wkt(mp) << std::endl
              << "output: " << bg::wkt(hull) << std::endl
              << std::endl;
              ;
      }
  }
  
  
  template <typename T>
  void test_all(int seed, int count, int field_size, int pcount, settings_type const& settings)
  {
      boost::timer t;
  
      typedef boost::minstd_rand base_generator_type;
  
      base_generator_type generator(seed);
  
      boost::uniform_int<> random_coordinate(0, field_size - 1);
      boost::variate_generator<base_generator_type&, boost::uniform_int<> >
          coordinate_generator(generator, random_coordinate);
  
      typedef bg::model::multi_point
          <
              bg::model::d2::point_xy<T>
          > mp;
  
      int index = 0;
      for(int i = 0; i < count; i++)
      {
          mp p;
          test_random_multi_points<mp>(p, index, coordinate_generator, pcount, settings);
      }
      std::cout
          << "points: " << index
          << " type: " << typeid(T).name()
          << " time: " << t.elapsed()  << std::endl;
  }
  
  int main(int argc, char** argv)
  {
      try
      {
          namespace po = boost::program_options;
          po::options_description description("=== random_multi_points ===\nAllowed options");
  
          std::string type = "double";
          int count = 1;
          int seed = static_cast<unsigned int>(std::time(0));
          int pcount = 3;
          int field_size = 10;
          settings_type settings;
  
          description.add_options()
              ("help", "Help message")
              ("seed", po::value<int>(&seed), "Initialization seed for random generator")
              ("count", po::value<int>(&count)->default_value(1), "Number of tests")
              ("number", po::value<int>(&pcount)->default_value(30), "Number of points")
              ("size", po::value<int>(&field_size)->default_value(10), "Size of the field")
              ("type", po::value<std::string>(&type)->default_value("double"), "Type (int,float,double)")
              ("wkt", po::value<bool>(&settings.wkt)->default_value(false), "Create a WKT of the inputs, for all tests")
              ("svg", po::value<bool>(&settings.svg)->default_value(false), "Create a SVG for all tests")
          ;
  
          po::variables_map varmap;
          po::store(po::parse_command_line(argc, argv, description), varmap);
          po::notify(varmap);
  
          if (varmap.count("help"))
          {
              std::cout << description << std::endl;
              return 1;
          }
  
          if (type == "float")
          {
              test_all<float>(seed, count, field_size, pcount, settings);
          }
          else if (type == "double")
          {
              test_all<double>(seed, count, field_size, pcount, settings);
          }
          else if (type == "int")
          {
              test_all<int>(seed, count, field_size, pcount, settings);
          }
  
      }
      catch(std::exception const& e)
      {
          std::cout << "Exception " << e.what() << std::endl;
      }
      catch(...)
      {
          std::cout << "Other exception" << std::endl;
      }
  
      return 0;
  }
  