ga_pixel.hpp

/*
 * Copyright (C) 2007,2008   Alex Shulgin
 *
 * This file is part of png++ the C++ wrapper for libpng.  PNG++ is free
 * software; the exact copying conditions are as follows:
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 *
 * 3. The name of the author may not be used to endorse or promote products
 * derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
 * NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
#ifndef PNGPP_GA_PIXEL_HPP_INCLUDED
#define PNGPP_GA_PIXEL_HPP_INCLUDED

#include <limits>

#include "types.hpp"
#include "pixel_traits.hpp"

namespace png
{

    /**
     * \brief Basic Gray+Alpha pixel type.
     */
    template< typename T >
    struct basic_ga_pixel
    {
        typedef pixel_traits< basic_ga_pixel< T > > traits;

        /**
         * \brief Constructs basic_ga_pixel object from \a value and
         * \a alpha components passed as parameters.  Alpha defaults
         * to full opacity.
         */
        basic_ga_pixel(T value = 0, T alpha = traits::get_alpha_filler())
            : value(value), alpha(alpha)
        {
        }

        T value;
        T alpha;
    };

    /**
     * \brief The 8-bit Gray+Alpha pixel type.
     */
    typedef basic_ga_pixel< byte > ga_pixel;

    /**
     * \brief The 16-bit Gray+Alpha pixel type.
     */
    typedef basic_ga_pixel< uint_16 > ga_pixel_16;

    /**
     * \brief Pixel traits specialization for basic_ga_pixel.
     */
    template< typename T >
    struct pixel_traits< basic_ga_pixel< T > >
        : basic_pixel_traits< basic_ga_pixel< T >, T, color_type_ga >,
          basic_alpha_pixel_traits< T >
    {
    };

} // namespace png

#endif // PNGPP_GA_PIXEL_HPP_INCLUDED