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#include <CGAL/Linear_cell_complex_for_combinatorial_map.h>
#include <CGAL/Linear_cell_complex_for_generalized_map.h>
#include <CGAL/Delaunay_triangulation_2.h>
#include <CGAL/Triangulation_2_to_lcc.h>
#include <iostream>
#include <fstream>
#include <cassert>
// This example works both with cmap and gmap as combinatorial data structure.
//typedef CGAL::Linear_cell_complex_for_combinatorial_map<2> LCC_2;
typedef CGAL::Linear_cell_complex_for_generalized_map<2> LCC_2;
typedef LCC_2::Dart_descriptor Dart_descriptor;
typedef LCC_2::Point Point;
typedef CGAL::Delaunay_triangulation_2<LCC_2::Traits> Triangulation;
// Function used to display the voronoi diagram.
void display_voronoi(LCC_2& alcc, Dart_descriptor adart)
{
// We remove the infinite face plus all the faces adjacent to it.
// Indeed, we cannot view these faces since they do not have
// a "correct geometry".
std::stack<Dart_descriptor> toremove;
LCC_2::size_type mark_toremove=alcc.get_new_mark();
// adart belongs to the infinite face.
toremove.push(adart);
CGAL::mark_cell<LCC_2,2>(alcc, adart, mark_toremove);
// Now we get all the faces adjacent to the infinite face.
for (LCC_2::Dart_of_cell_range<2>::iterator
it=alcc.darts_of_cell<2>(adart).begin(),
itend=alcc.darts_of_cell<2>(adart).end(); it!=itend; ++it)
{
if ( !alcc.is_marked(alcc.opposite<2>(it), mark_toremove) )
{
CGAL::mark_cell<LCC_2,2>(alcc, alcc.opposite<2>(it), mark_toremove);
toremove.push(alcc.opposite<2>(it));
}
}
while( !toremove.empty() )
{
alcc.remove_cell<2>(toremove.top());
toremove.pop();
}
assert(alcc.is_without_boundary(1));
std::cout<<"Voronoi subdvision, only finite faces:"<<std::endl<<" ";
alcc.display_characteristics(std::cout) << ", valid="
<< alcc.is_valid()
<< std::endl;
}
template<typename LCC, typename TR>
void transform_dart_to_their_dual(LCC& alcc, LCC& adual,
std::map<typename TR::Face_handle,
typename LCC::Dart_descriptor>& assoc)
{
typename LCC::Dart_range::iterator it1=alcc.darts().begin();
typename LCC::Dart_range::iterator it2=adual.darts().begin();
std::map<typename LCC::Dart_descriptor, typename LCC::Dart_descriptor> dual;
for ( ; it1!=alcc.darts().end(); ++it1, ++it2 )
{
dual[it1]=it2;
}
for ( typename std::map<typename TR::Face_handle, typename LCC::Dart_descriptor>
::iterator it=assoc.begin(), itend=assoc.end(); it!=itend; ++it)
{
assoc[it->first]=dual[it->second];
}
}
template<typename LCC, typename TR>
void set_geometry_of_dual(LCC& alcc, TR& tr,
std::map<typename TR::Face_handle,
typename LCC::Dart_descriptor>& assoc)
{
for ( typename std::map<typename TR::Face_handle, typename LCC::Dart_descriptor>
::iterator it=assoc.begin(), itend=assoc.end(); it!=itend; ++it)
{
if ( !tr.is_infinite(it->first) )
alcc.set_vertex_attribute
(it->second,alcc.create_vertex_attribute(tr.circumcenter(it->first)));
else
alcc.set_vertex_attribute(it->second,alcc.create_vertex_attribute());
}
}
int main(int narg, char** argv)
{
if (narg>1 && (!strcmp(argv[1],"-h") || !strcmp(argv[1],"-?")) )
{
std::cout<<"Usage : voronoi_2 filename"<<std::endl
<<" filename being a fine containing 2D points used to "
<<" compute the Delaunay_triangulation_2."<<std::endl;
return EXIT_FAILURE;
}
std::string filename;
if ( narg==1 )
{
filename="data/points_2";
std::cout<<"No filename given: use "<<filename<<" by default."<<std::endl;
}
else { filename=std::string(argv[1]); }
// 1) Compute the Delaunay_triangulation_2.
Triangulation T;
std::ifstream iFile(filename.c_str());
if (!iFile)
{
std::cout << "Problem reading file " << filename << std::endl;
return EXIT_FAILURE;
}
std::istream_iterator<Point> begin(iFile), end;
T.insert(begin, end);
assert(T.is_valid(false));
// 2) Convert the triangulation into a 2D lcc.
LCC_2 lcc;
std::map<Triangulation::Face_handle,
LCC_2::Dart_descriptor > face_to_dart;
Dart_descriptor d=CGAL::import_from_triangulation_2<LCC_2, Triangulation>
(lcc, T, &face_to_dart);
assert(lcc.is_without_boundary());
std::cout<<"Delaunay triangulation :"<<std::endl<<" ";
lcc.display_characteristics(std::cout) << ", valid="
<< lcc.is_valid() << std::endl;
// 3) Compute the dual lcc.
LCC_2 dual_lcc;
Dart_descriptor dd=lcc.dual(dual_lcc, d);
// Here, dual_lcc is the 2D Voronoi diagram.
assert(dual_lcc.is_without_boundary());
// 4) We update the geometry of dual_lcc by using the std::map
// face_to_dart.
transform_dart_to_their_dual<LCC_2,Triangulation>
(lcc, dual_lcc, face_to_dart);
set_geometry_of_dual<LCC_2,Triangulation>(dual_lcc, T, face_to_dart);
// 5) Display the dual_lcc characteristics.
std::cout<<"Voronoi subdvision :"<<std::endl<<" ";
dual_lcc.display_characteristics(std::cout) << ", valid="
<< dual_lcc.is_valid()
<< std::endl;
display_voronoi(dual_lcc, dd);
return EXIT_SUCCESS;
}
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