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[Kiên Kiêu <>]

Hi,

it seems as if there is a problem when reading an arrangement from a file. 
In the program below, I create a very simple arrangement of segments (code 
taken from the CGAL documentation) with 2 faces (1 unbounded). Then the 
arrangement is saved into a file and another one is read from it. In the 
arrangement read from the file, there are two faces, but both are 
considered as bounded.

If this is really a bug, is there a way to fix it?

I am using CGAL 3.3.1 on a Linux PC.

////////////////////////////////////////////////////////

/**********************************************************
  *                                                        *
  *   TEST PROGRAM THAT SHOWS THAT THERE IS NO             *
  *   UNBOUNDED FACE IN AN ARRANGEMENT READ FROM           *
  *   FILE                                                 *
  **********************************************************/

// Author: Kien Kieu
// Tested in January 2008 on CGAL 3.3.1

#include <CGAL/Cartesian.h>
#include <CGAL/MP_Float.h>
#include <CGAL/Quotient.h>
#include <CGAL/Arr_segment_traits_2.h>
#include <CGAL/Arrangement_2.h>
#include <CGAL/IO/Arr_iostream.h>

typedef CGAL::Quotient<CGAL::MP_Float>     Number_type;
typedef CGAL::Cartesian<Number_type>       Kernel;
typedef CGAL::Arr_segment_traits_2<Kernel> Traits_2;
typedef Traits_2::Point_2                  Point_2;
typedef Traits_2::X_monotone_curve_2       Segment_2;
typedef CGAL::Arrangement_2<Traits_2>      Arrangement_2;

int main()
{
   Arrangement_2   arr;
   Segment_2       cv[3];
   Point_2         p1 (0, 0), p2 (0, 4), p3 (4, 0);

   cv[0] = Segment_2 (p1, p2);
   cv[1] = Segment_2 (p2, p3);
   cv[2] = Segment_2 (p3, p1);
   CGAL::insert_curves (arr, &cv[0], &cv[3]);

   std::cout << "Number of faces: " << arr.number_of_faces();
   std::cout << " (" << arr.number_of_unbounded_faces() << " unbounded)" << 
std::endl;

   std::cout << "Saving arrangement to file test_unbounded_face.txt" << 
std::endl;

   std::ofstream output("test_unbounded_face.txt");
   output << arr;
   output.close();

   std::cout << "Reading arrangement from file test_unbounded_face.txt" << 
std::endl;

   std::ifstream input("test_unbounded_face.txt");
   Arrangement_2 read_arr;
   input >> read_arr;
   input.close();

   std::cout << "Number of faces: " << read_arr.number_of_faces();
   std::cout << " (" << read_arr.number_of_unbounded_faces() << " unbounded)" 
<< std::endl;

   return (0);
}

///////////////////////////////////////////////////////

Ouput:

Number of faces: 2 (1 unbounded)
Saving arrangement to file test_unbounded_face.txt
Reading arrangement from file test_unbounded_face.txt
Number of faces: 2 (0 unbounded)

--
Kiên Kiêu                    tel  : + 33 (0)1 34 65 28 16
Unité MIA, INRA              fax  : + 33 (0)1 34 65 22 17
Domaine de Vilvert           email: 

F-78352 Jouy-en-Josas Cedex  url  : http://www.inra.fr/miaj/