CGAL 5.3 - 2D Straight Skeleton and Polygon Offsetting
Straight_skeleton_2/Show_straight_skeleton.cpp
#include<vector>
#include<iterator>
#include<iostream>
#include<iomanip>
#include<string>
#include <fstream>
#include <cassert>
#include<boost/shared_ptr.hpp>
#include<CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include<CGAL/Polygon_with_holes_2.h>
#include<CGAL/create_straight_skeleton_from_polygon_with_holes_2.h>
#include "dump_to_eps.h"
typedef K::Point_2 Point ;
typedef CGAL::Polygon_2<K> Polygon_2 ;
typedef CGAL::Polygon_with_holes_2<K> Polygon_with_holes ;
typedef CGAL::Straight_skeleton_2<K> Straight_skeleton ;
typedef boost::shared_ptr<Straight_skeleton> Straight_skeleton_ptr ;
int main( int argc, char* argv[] )
{
Polygon_with_holes input ;
if ( argc > 1 )
{
std::string name = argv[1] ;
std::cout << "Input file: " << name << std::endl ;
std::ifstream is(name.c_str()) ;
if ( is )
{
is >> input ;
assert(input.outer_boundary().is_counterclockwise_oriented());
for(Polygon_with_holes::Hole_const_iterator it = input.holes_begin();
it != input.holes_end();
++it){
assert(it->is_counterclockwise_oriented());
}
//check the validity of the input and fix orientation
if (!input.outer_boundary().is_simple())
{
std::cerr << "ERROR: outer boundary is not simple.";
return 1;
}
if ( input.outer_boundary().is_clockwise_oriented() )
input.outer_boundary().reverse_orientation();
int k=0;
for (Polygon_with_holes::Hole_iterator it = input.holes_begin();
it!=input.holes_end(); ++it, ++k)
{
if (!it->is_simple())
{
std::cerr << "ERROR: hole "<< k << " is not simple.\n";
return 1;
}
if (it->is_counterclockwise_oriented())
it->reverse_orientation();
}
Straight_skeleton_ptr ss = CGAL::create_interior_straight_skeleton_2(input);
if ( ss )
{
std::string eps_name ;
if ( argc > 2 )
eps_name = argv[2];
else eps_name = name + ".skeleton.eps" ;
std::ofstream eps(eps_name.c_str()) ;
if ( eps )
{
std::cerr << "Result: " << eps_name << std::endl ;
dump_to_eps(input,*ss,eps);
}
else
{
std::cerr << "Could not open result file: " << eps_name << std::endl ;
}
}
else
{
std::cerr << "ERROR creating interior straight skeleton" << std::endl ;
}
}
else
{
std::cerr << "Could not open input file: " << name << std::endl ;
}
}
else
{
std::cerr << "Computes the straight skeleton in the interior of a polygon with holes and draws it in an EPS file." << std::endl
<< std::endl
<< "Usage: show_straight_skeleton <intput_file> [output_eps_file]" << std::endl
<< std::endl
<< " intput_file Text file describing the input polygon with holes." << std::endl
<< " (See input_file_format.txt for details)" << std::endl
<< " output_file [default='innput_file.skeleton.eps']" << std::endl ;
}
return 0;
}