segment_2d.h

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// -*-c++-*-

 
/*
 *Copyright:
 
 Copyright (C) Hidehisa Akiyama, Hiroki Shimora
 
 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_SEGMENT2D_H
#define RCSC_GEOM_SEGMENT2D_H
 
#include <geom/line_2d.h>
#include <geom/vector_2d.h>
 
#include <cmath>
 
namespace rcsc {

class Segment2D {
private:
 
    static const double EPSILON; 
    static const double CALC_ERROR; 
 
    Vector2D M_origin; 
    Vector2D M_terminal; 

    Segment2D();
 
    bool checkIntersectsOnLine( const Vector2D & p ) const;
 
public:
    Segment2D( const Vector2D & origin,
               const Vector2D & terminal )
        : M_origin( origin ),
          M_terminal( terminal )
      { }

    Segment2D( const double & origin_x,
               const double & origin_y,
               const double & terminal_x,
               const double & terminal_y )
        : M_origin( origin_x, origin_y ),
          M_terminal( terminal_x, terminal_y )
      { }

    Segment2D( const Vector2D & origin,
               const double & length,
               const AngleDeg & dir )
        : M_origin( origin ),
          M_terminal( origin + Vector2D::from_polar( length, dir ) )
      { }

    const
    Segment2D & assign( const Vector2D & origin,
                        const Vector2D & terminal )
      {
          M_origin = origin;
          M_terminal = terminal;
          return *this;
      }

    const
    Segment2D & assign( const double & origin_x,
                        const double & origin_y,
                        const double & terminal_x,
                        const double & terminal_y )
      {
          M_origin.assign( origin_x, origin_y );
          M_terminal.assign( terminal_x, terminal_y );
          return *this;
      }

    const
    Segment2D & assign( const Vector2D & origin,
                        const double & length,
                        const AngleDeg & dir )
      {
          M_origin = origin;
          M_terminal = origin + Vector2D::from_polar( length, dir );
          return *this;
      }

    bool isValid() const
      {
          return ! origin().equalsWeakly( terminal() );
      }

    const
    Vector2D & origin() const
      {
          return M_origin;
      }

    const
    Vector2D & terminal() const
      {
          return M_terminal;
      }

    Line2D line() const
      {
          return Line2D( origin(), terminal() );
      }

    double length() const
      {
          return origin().dist( terminal() );
      }

    AngleDeg direction() const
      {
          return ( terminal() - origin() ).th();
      }
 
 

    const
    Segment2D & swap()
      {
          // std::swap( M_origin, M_terminal );
          Vector2D tmp = M_origin;
          M_origin = M_terminal;
          M_terminal = tmp;
          return *this;
      }

    const
    Segment2D & reverse()
      {
          return swap();
      }

    Segment2D reversedSegment() const
      {
          return Segment2D( *this ).reverse();
      }

    Line2D perpendicularBisector() const
      {
          return Line2D::perpendicular_bisector( origin(), terminal() );
      }

    bool contains( const Vector2D & p ) const
      {
        return ( ( p.x - origin().x ) * ( p.x - terminal().x ) <= CALC_ERROR //EPSILON
                   && ( p.y - origin().y ) * ( p.y - terminal().y ) <= CALC_ERROR); //EPSILON );
      }

    bool equals( const Segment2D & other ) const
      {
          return this->origin().equals( other.origin() )
              && this->terminal().equals( other.terminal() );
      }

    bool equalsWeakly( const Segment2D & other ) const
      {
          return this->origin().equalsWeakly( other.origin() )
              && this->terminal().equalsWeakly( other.terminal() );
      }
 

    Vector2D projection( const Vector2D & p ) const;

    Vector2D intersection( const Segment2D & other,
                           const bool allow_end_point ) const;

    Vector2D intersection( const Line2D & l ) const;

    bool existIntersection( const Segment2D & other ) const;

    bool intersects( const Segment2D & other ) const
      {
          return existIntersection( other );
      }

    bool existIntersectionExceptEndpoint( const Segment2D & other ) const;

    bool intersectsExceptEndpoint( const Segment2D & other ) const
      {
          return existIntersectionExceptEndpoint( other );
      }

    bool existIntersection( const Line2D & l ) const;

    bool intersects( const Line2D & l ) const
      {
          return existIntersection( l );
      }

    Vector2D nearestPoint( const Vector2D & p ) const;

    double dist( const Vector2D & p ) const;

    double dist( const Segment2D & seg ) const;

    double farthestDist( const Vector2D & p ) const;

    bool onSegment( const Vector2D & p ) const;

    bool onSegmentWeakly( const Vector2D & p ) const;

    std::ostream & print( std::ostream & os ) const
      {
          os << '[' << origin() << '-' << terminal() << ']';
          return os;
      }
 
};
 
}
 
#endif