/*
  offset.hh -- part of GNU LilyPond

  (c) 1996--2004 Han-Wen Nienhuys
*/

#ifndef OFFSET_HH
#define OFFSET_HH

#include "flower-proto.hh"
#include "real.hh"
#include "axes.hh"
#include "arithmetic-operator.hh"
#include "string.hh"

Offset complex_multiply (Offset, Offset);
Offset complex_divide (Offset, Offset);
Offset complex_exp (Offset);


/*

This is a mixture a 2D vector. Sometimes it can
also be convenient to think of 2D vectors as complex numbers
(ie. x + i y). The naming of some methods reflects that.

*/
class Offset 
{
public:
  Real coordinate_a_[NO_AXES];
    
  Real &operator[] (Axis i) 
  {
    return coordinate_a_[i];
  }

  Real operator[] (Axis i) const
  {
    return coordinate_a_[i];
  }
    
  Offset& operator+= (Offset o) 
  {
    (*this)[X_AXIS] += o[X_AXIS];
    (*this)[Y_AXIS] += o[Y_AXIS];
    return *this;
  }

  Offset operator - () const 
  {
    Offset o = *this;
    
    o[X_AXIS]  = - o[X_AXIS];
    o[Y_AXIS]  = - o[Y_AXIS];
    return o;
  }

  Offset& operator-= (Offset o) 
  {
    (*this)[X_AXIS] -= o[X_AXIS];
    (*this)[Y_AXIS] -= o[Y_AXIS];

    return *this;
  }
  
  Offset &scale (Offset o) 
  {
    (*this)[X_AXIS] *= o[X_AXIS];
    (*this)[Y_AXIS] *= o[Y_AXIS];

    return *this;
  }

  Offset &operator *= (Real a) 
  {
    (*this)[X_AXIS] *= a;
    (*this)[Y_AXIS] *= a;

    return *this;
  }
      
  Offset (Real ix , Real iy) 
  {
    coordinate_a_[X_AXIS] =ix;
    coordinate_a_[Y_AXIS] =iy;    
  }

  Offset () 
  {
    coordinate_a_[X_AXIS] = coordinate_a_[Y_AXIS]= 0.0;
  }

  String to_string () const;

  Offset& mirror (Axis a)
  {
    coordinate_a_[a] = - coordinate_a_[a];
    return *this;
  }
  
  Real arg () const;
  Real length () const;

  Offset operator *= (Offset z2) 
  {
    *this = complex_multiply (*this, z2);
    return *this;
  }

};

IMPLEMENT_ARITHMETIC_OPERATOR (Offset, +);
IMPLEMENT_ARITHMETIC_OPERATOR (Offset, -);
IMPLEMENT_ARITHMETIC_OPERATOR (Offset, *);

inline Offset
operator* (Real o1, Offset o2)
{
  o2 *= o1;
  return o2;
}

inline Offset
operator* (Offset o1, Real o2)
{
  o1 *= o2;
  return o1;
}

inline Offset
mirror (Offset o, Axis a)
{
  o.mirror (a);
  return o;
}

inline
Real
dot_product  (Offset o1, Offset o2)
{
  return o1[X_AXIS] * o2[X_AXIS] + o1[Y_AXIS] * o2[Y_AXIS];
}


#endif /* OFFSET_HH */


