Function

CGAL::import_from_plane_graph<LCC>

#include <CGAL/Linear_cell_complex_constructors.h>


template<class LCC>
typename LCC::Dart_handle import_from_plane_graph ( LCC& lcc, std::istream& ais)
Imports an embedded plane graph read from ais into lcc. Objects are added in lcc, existing darts are not modified. Returns a dart created during the import.
Precondition: LCC::dimension≥2 and LCC::ambient_dimension==2.

File format

The file format must be the following. First the number of vertices and the number of edges of the planar graph. Then, for each vertex of the planar graph, the coordinates of the ith vertex (two numbers for x and y coordinates). The first vertex index is 0. Then for each edge of the planar graph, the two indices of the two vertices (two numbers between 0 and the number of vertices minus 1).

Here a small example:

5 6
1.0 3.0   0.0 2.0   2.0 2.0   0.0 0.0   2.0 0.0
0 1   0 2   1 2   1 3   2 4   3 4
Example of import_graph reading the above file as istream.
Left: A planar graph embedded in the plane with P0=(1.0,3.0), P1=(0.0,2.0), P2=(2.0,2.0), P3=(0.0,0.0), P4=(2.0,0.0). Right: the 2D linear cell complex reconstructed.

See Also

CGAL::import_from_triangulation_3<LCC,Triangulation>
CGAL::import_from_polyhedron_3<LCC,Polyhedron>