/************ Basic quad-edge navigation and operations ************/
 CV_INLINE  CvSubdiv2DEdge  cvSubdiv2DNextEdge( CvSubdiv2DEdge edge );
 CV_INLINE  CvSubdiv2DEdge  cvSubdiv2DNextEdge( CvSubdiv2DEdge edge )
 {
     return  CV_SUBDIV2D_NEXT_EDGE(edge);
 }

 CV_INLINE  CvSubdiv2DEdge  cvSubdiv2DRotateEdge( CvSubdiv2DEdge edge, int rotate );
 CV_INLINE  CvSubdiv2DEdge  cvSubdiv2DRotateEdge( CvSubdiv2DEdge edge, int rotate )
 {
     return  (edge & ~3) + ((edge + rotate) & 3);
 }

 CV_INLINE  CvSubdiv2DEdge  cvSubdiv2DSymEdge( CvSubdiv2DEdge edge );
 CV_INLINE  CvSubdiv2DEdge  cvSubdiv2DSymEdge( CvSubdiv2DEdge edge )
 {
     return edge ^ 2;
 }

 CV_INLINE  CvSubdiv2DEdge  cvSubdiv2DGetEdge( CvSubdiv2DEdge edge, CvNextEdgeType type );
 CV_INLINE  CvSubdiv2DEdge  cvSubdiv2DGetEdge( CvSubdiv2DEdge edge, CvNextEdgeType type )
 {
     CvQuadEdge2D* e = (CvQuadEdge2D*)(edge & ~3);
     edge = e->next[(edge + (int)type) & 3];
     return  (edge & ~3) + ((edge + ((int)type >> 4)) & 3);
 }

 CV_INLINE  CvSubdiv2DPoint*  cvSubdiv2DEdgeOrg( CvSubdiv2DEdge edge );
 CV_INLINE  CvSubdiv2DPoint*  cvSubdiv2DEdgeOrg( CvSubdiv2DEdge edge )
 {
     CvQuadEdge2D* e = (CvQuadEdge2D*)(edge & ~3);
     return e->pt[edge & 3];
 }

 CV_INLINE  CvSubdiv2DPoint*  cvSubdiv2DEdgeDst( CvSubdiv2DEdge edge );
 CV_INLINE  CvSubdiv2DPoint*  cvSubdiv2DEdgeDst( CvSubdiv2DEdge edge )
 {
     CvQuadEdge2D* e = (CvQuadEdge2D*)(edge & ~3);
     return e->pt[(edge + 2) & 3];
 }

 CV_INLINE  double  cvTriangleArea( CvPoint2D32f a, CvPoint2D32f b, CvPoint2D32f c );
 CV_INLINE  double  cvTriangleArea( CvPoint2D32f a, CvPoint2D32f b, CvPoint2D32f c )
 {
     return (b.x - a.x) * (c.y - a.y) - (b.y - a.y) * (c.x - a.x);
 }

 /*F///////////////////////////////////////////////////////////////////////////////////////
 //    Name:    cvCreateSubdiv2D
 //    Purpose: creates initially empty planar subdivision structure
 //    Context:
 //    Parameters:
 //      subdiv_type - type of subdivision
 //      header_size - size of header(>= sizeof(CvSubdiv2D))
 //      quadedge_size - size of quad-edges(>= sizeof(CvQuadEdge2D))
 //      vtx_size - size of vertices(>= sizeof(CvSubdiv2DPoint))
 //      storage  - size of memory storage
 //    Returns:
 //      created subdivision
 //F*/
 OPENCVAPI  CvSubdiv2D*  cvCreateSubdiv2D( int subdiv_type, int header_size,
                                        int vtx_size, int quadedge_size,
                                        CvMemStorage* storage );

 /*F///////////////////////////////////////////////////////////////////////////////////////
 //    Name:    cvSubdiv2DLocate
 //    Purpose:  finds location of the point within the Delaunay triangulation
 //              origin point of the second edge
 //    Context:
 //    Parameters:
 //      subdiv - subdivison
 //      pt     - searched point
 //      _edge  - bounding edge for facet, containing the point
 //      _point - vertex(if searched point coincides with the vertex)
 //F*/
 OPENCVAPI  CvSubdiv2DPointLocation  cvSubdiv2DLocate(
                                CvSubdiv2D* subdiv, CvPoint2D32f pt,
                                CvSubdiv2DEdge *_edge,
                                CvSubdiv2DPoint** _point CV_DEFAULT(0) );

 /*F///////////////////////////////////////////////////////////////////////////////////////
 //    Name:    cvInitSubdivDelaunay2D
 //    Purpose:  connect destination point of the first edge with
 //              origin point of the second edge
 //    Context:
 //    Parameters:
 //      subdiv - subdivison
 //      pt     - searched point
 //      _edge  - bounding edge for facet, containing the point
 //      _point - vertex(if searched point coincides with the vertex)
 //F*/
 OPENCVAPI  void  cvInitSubdivDelaunay2D( CvSubdiv2D* subdiv, CvRect rect );

 /*F///////////////////////////////////////////////////////////////////////////////////////
 //    Name:    cvSubdivDelaunay2DInsert
 //    Purpose:  insert the point into the triangulation
 //    Context:
 //    Parameters:
 //      subdiv - subdivison
 //      pt     - inserted point
 //F*/
 OPENCVAPI  CvSubdiv2DPoint*  cvSubdivDelaunay2DInsert( CvSubdiv2D* subdiv, CvPoint2D32f pt);

 /*F///////////////////////////////////////////////////////////////////////////////////////
 //    Name:    cvCalcSubdivVoronoi2D
 //    Purpose:  calculates Voronoi tesselation( Coordinates of Voronoi points)
 //    Context:
 //    Parameters:
 //      subdiv - subdivison
 //    Note:
 //      Before calculations the function checks the flag, indicating that
 //      the Voronoi tesselation is already calculated.
 //      If subdivision is modified(some points have been inserted), the flag is cleared.
 //F*/
 OPENCVAPI  void  cvCalcSubdivVoronoi2D( CvSubdiv2D* subdiv );

 /*F///////////////////////////////////////////////////////////////////////////////////////
 //    Name:    cvClearSubdivVoronoi2D
 //    Purpose:  removes all Voronoi points from the tesselation.
 //    Context:
 //    Parameters:
 //      subdiv - subdivison
 //    Note:
 //      The function is called implicitly from the cvCalcSubdivVoronoi2D
 //      before Voronoi tesselation is calculated.
 //F*/
 OPENCVAPI  void  cvClearSubdivVoronoi2D( CvSubdiv2D* subdiv );