la.h

#ifndef CVD_LA_H
#define CVD_LA_H

#include <iostream>

namespace CVD
{

// CVD::La
// Template class to represent luminance and alpha components
//
template <typename T>
class La
{
    public:
    La() { }
    La(T l, T a)
        : luminance(l)
        , alpha(a)
    {
    }

    T luminance; 
    T alpha; 

    La<T>& operator=(const La<T>& c)
    {
        luminance = c.luminance;
        alpha = c.alpha;
        return *this;
    }

    template <typename T2>
    La<T>& operator=(const La<T2>& c)
    {
        luminance = static_cast<T>(c.luminance);
        alpha = static_cast<T>(c.alpha);
        return *this;
    }

    bool operator==(const La<T>& c) const
    {
        return luminance == c.luminance && alpha == c.alpha;
    }

    bool operator!=(const La<T>& c) const
    {
        return luminance != c.luminance || alpha != c.alpha;
    }
};

template <typename T>
std::ostream& operator<<(std::ostream& os, const La<T>& x)
{
    return os << "(" << x.luminance << "," << x.alpha << ")";
}

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

} // end namespace
#endif