circle_2d.h

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// -*-c++-*-
 
/*
 *Copyright:
 
 Copyright (C) Hidehisa Akiyama
 
 This code is free software; you can redistribute it and/or
 modify it under the terms of the GNU Lesser General Public
 License as published by the Free Software Foundation; either
 version 3 of the License, or (at your option) any later version.
 
 This library is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 Lesser General Public License for more details.
 
 You should have received a copy of the GNU Lesser General Public
 License along with this library; if not, write to the Free Software
 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 
 *EndCopyright:
 */
 
 
#ifndef RCSC_GEOM_CIRCLE2D_H
#define RCSC_GEOM_CIRCLE2D_H
 
#include <iostream>
 
#include <rcsc/geom/region_2d.h>
#include <rcsc/geom/vector_2d.h>
 
namespace rcsc {
 
class Line2D;
class Ray2D;
class Segment2D;
 
class Circle2D
    : public Region2D {
private:
 
    Vector2D M_center;
 
    double M_radius;
 
    static const double EPSILON;
 
 
public:
    Circle2D()
        : M_center( 0.0, 0.0 ),
          M_radius( 0.0 )
      { }
 
    Circle2D( const Vector2D & c,
              const double r )
        : M_center( c ),
          M_radius( r )
      {
          if ( r < 0.0 )
          {
              std::cerr << "Circle2D::Circle2D(). radius must be positive value."
                        << std::endl;
              M_radius = 0.0;
          }
      }
 
    const Circle2D & assign( const Vector2D & c,
                       const double r )
      {
          M_center = c;
          M_radius = r;
          if ( r < 0.0 )
          {
              std::cerr << "Circle2D::assign(). radius must be positive value."
                        << std::endl;
              M_radius = 0.0;
          }
          return *this;
      }
 
    virtual
    double area() const
      {
          return AngleDeg::PI * M_radius * M_radius;
      }
 
    virtual
    bool contains( const Vector2D & point ) const
      {
          return M_center.dist2( point ) < M_radius * M_radius;
      }
 
    const Vector2D & center() const
      {
          return M_center;
      }
 
    double radius() const
      {
          return M_radius;
      }
 
    int intersection( const Line2D & line,
                      Vector2D * sol1,
                      Vector2D * sol2 ) const;
 
    int intersection( const Ray2D & ray,
                      Vector2D * sol1,
                      Vector2D * sol2 ) const;
 
    int intersection( const Segment2D & segment,
                      Vector2D * sol1,
                      Vector2D * sol2 ) const;
 
    int intersection( const Circle2D & circle,
                      Vector2D * sol1,
                      Vector2D * sol2 ) const;
 
    // static utility
 
    static
    Circle2D circumcircle( const Vector2D & p0,
                           const Vector2D & p1,
                           const Vector2D & p2 );
 
    static
    bool contains( const Vector2D & point,
                   const Vector2D & p0,
                   const Vector2D & p1,
                   const Vector2D & p2 );
};
 
}
 
#endif