rgba.h

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/*                       
    This file is part of the CVD Library.

    Copyright (C) 2005 The Authors

    This library 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 2.1 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., 
    51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
*/
#ifndef CVD_RGBA_H
#define CVD_RGBA_H

#include <iostream>
#include "is_pod.h"

namespace CVD {


// CVD::Rgba
// Template class to represent red, green, blue and alpha components
//
template <typename T>
class Rgba
{
public:
    Rgba() {}
    Rgba(T r, T g, T b, T a) : red(r), green(g), blue(b), alpha(a) {}

   T red; 
   T green; 
   T blue; 
   T alpha; 

   Rgba<T>& operator=(const Rgba<T>& c)
      {red = c.red; green = c.green; blue = c.blue; alpha = c.alpha; return *this;}

   template <typename T2>
     Rgba<T>& operator=(const Rgba<T2>& c){
     red = static_cast<T>(c.red);
     green = static_cast<T>(c.green); 
     blue = static_cast<T>(c.blue); 
     alpha = static_cast<T>(c.alpha); 
     return *this;
   }

    bool operator==(const Rgba<T>& c) const
      {return red == c.red && green == c.green && blue == c.blue && alpha == c.alpha;}

    bool operator!=(const Rgba<T>& c) const
      {return red != c.red || green != c.green || blue != c.blue || alpha != c.alpha;}

//   T to_grey() const {return 0.3*red + 0.6*green + 0.1*blue;}
};

template <typename T>
std::ostream& operator <<(std::ostream& os, const Rgba<T>& x)
{
   return os << "(" << x.red << "," << x.green << ","
             << x.blue << "," << x.alpha << ")";
}

inline std::ostream& operator <<(std::ostream& os, const Rgba<unsigned char>& x)
{
   return os << "(" << static_cast<unsigned int>(x.red) << ","
             << static_cast<unsigned int>(x.green) << ","
             << static_cast<unsigned int>(x.blue) << ","
             << static_cast<unsigned int>(x.alpha) << ")";
}

namespace Internal
{
  template<class C> struct is_POD<Rgba<C> >
  {
    enum { is_pod = is_POD<C>::is_pod };
  };
}


} // end namespace 
#endif