Traits Class Adapter for 2D Smallest Enclosing Circle to 2D Cartesian Points (Min_circle_2_adapterC2)

Definition

The class Min_circle_2_adapterC2<PT,DA> interfaces the 2D optimisation algorithm for smallest enclosing circles with the point class PT. The data accessor DA [KW97] is used to access the x- and y-coordinate of PT, i.e. PT is supposed to have a Cartesian representation of its coordinates.

#include <CGAL/Min_circle_2_adapterC2.h>

Types

Min_circle_2_adapterC2<PT,DA>::DA
	Data accessor for Cartesian coordinates.
Min_circle_2_adapterC2<PT,DA>::Point
	Point type.
Min_circle_2_adapterC2<PT,DA>::Circle
	Circle type.

Creation

Min_circle_2_adapterC2<PT,DA> adapter ( DA da = DA());

Min_circle_2_adapterC2<PT,DA> adapter ( Min_circle_2_adapterC2<PT,DA>);

Operations

Orientation	adapter.orientation ( Point p, Point q, Point r)
		returns constants LEFTTURN, COLLINEAR, or RIGHTTURN iff r lies properly to the left of, on, or properly to the right of the oriented line through p and q, resp.

See Also

Min_circle_2 , Min_circle_2_traits_2 , Min_circle_2_adapterH2 , Requirements of Traits Class Adapters to 2D Cartesian Points.

Example

The following example illustrates the use of the traits class adapters with your own point class. For the sake of simplicity, we expect a point class with Cartesian double coordinates and access functions x() and y(). Based on this we show how to implement and use data accessors.

Note: In this release correct results are only guaranteed if exact arithmetic is used, so this example (using inexact floating-point arithmetic) is only intended to illustrate the techniques.

#include <CGAL/Min_circle_2_adapterC2.h>
#include <CGAL/Min_circle_2.h>
using namespace CGAL;

// your own point class (Cartesian)
class PtC {
    // ...
  public:
    PtC( double x, double y);
    double  x( ) const;
    double  y( ) const;
    // ...
};

// the data accessor for PtC
class PtC_DA {
  public:
    typedef  double  FT;
    void  get( const PtC& p, double& x, double& y) const {
        x = p.x(); y = p.y();
    }
    double  get_x( const PtC& p) const { return( p.x()); }
    double  get_y( const PtC& p) const { return( p.y()); }
    void  set( PtC& p, double x, double y) const { p = PtC( x, y); }
};

// some typedefs
typedef  Min_circle_2_adapterC2 < PtC, PtC_DA >  AdapterC;
typedef  Min_circle_2 < AdapterC >               Min_circle;

// do something with Min_circle
Min_circle   mc( /*...*/ );