//
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// Copyright 2012 Chung-Lin Wen, Davide Anastasia
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//
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// Distributed under the Boost Software License, Version 1.0
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// See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt
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//
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#ifndef BOOST_GIL_EXTENSION_TOOLBOX_COLOR_SPACES_XYZ_HPP
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#define BOOST_GIL_EXTENSION_TOOLBOX_COLOR_SPACES_XYZ_HPP
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#include <boost/gil/color_convert.hpp>
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#include <boost/gil/typedefs.hpp>
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#include <boost/gil/detail/mp11.hpp>
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namespace boost{ namespace gil {
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/// \addtogroup ColorNameModel
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/// \{
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namespace xyz_color_space
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{
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/// \brief x Color Component
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struct x_t {};
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/// \brief y Color Component
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struct y_t {};
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/// \brief z Color Component
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struct z_t {};
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}
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/// \}
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/// \ingroup ColorSpaceModel
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using xyz_t = mp11::mp_list
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<
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xyz_color_space::x_t,
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xyz_color_space::y_t,
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xyz_color_space::z_t
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>;
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/// \ingroup LayoutModel
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using xyz_layout_t = layout<xyz_t>;
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BOOST_GIL_DEFINE_ALL_TYPEDEFS(32f, float32_t, xyz)
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/// \ingroup ColorConvert
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/// \brief RGB to XYZ
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/// <a href="http://www.brucelindbloom.com/index.html?Eqn_RGB_XYZ_Matrix.html">Link</a>
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/// \note rgb_t is assumed to be sRGB D65
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template <>
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struct default_color_converter_impl< rgb_t, xyz_t >
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{
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private:
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BOOST_FORCEINLINE
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float32_t inverse_companding(float32_t sample) const
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{
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if ( sample > 0.04045f )
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{
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return powf((( sample + 0.055f ) / 1.055f ), 2.4f);
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}
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else
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{
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return ( sample / 12.92f );
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}
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}
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public:
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template <typename P1, typename P2>
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void operator()( const P1& src, P2& dst ) const
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{
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using namespace xyz_color_space;
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float32_t red(
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inverse_companding(
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channel_convert<float32_t>(get_color(src, red_t()))));
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float32_t green(
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inverse_companding(
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channel_convert<float32_t>(get_color(src, green_t()))));
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float32_t blue(
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inverse_companding(
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channel_convert<float32_t>(get_color(src, blue_t()))));
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get_color( dst, x_t() ) =
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red * 0.4124564f +
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green * 0.3575761f +
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blue * 0.1804375f;
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get_color( dst, y_t() ) =
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red * 0.2126729f +
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green * 0.7151522f +
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blue * 0.0721750f;
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get_color( dst, z_t() ) =
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red * 0.0193339f +
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green * 0.1191920f +
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blue * 0.9503041f;
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}
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};
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/// \ingroup ColorConvert
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/// \brief XYZ to RGB
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template <>
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struct default_color_converter_impl<xyz_t,rgb_t>
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{
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private:
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BOOST_FORCEINLINE
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float32_t companding(float32_t sample) const
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{
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if ( sample > 0.0031308f )
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{
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return ( 1.055f * powf( sample, 1.f/2.4f ) - 0.055f );
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}
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else
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{
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return ( 12.92f * sample );
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}
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}
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public:
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template <typename P1, typename P2>
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void operator()( const P1& src, P2& dst) const
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{
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using namespace xyz_color_space;
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// Note: ideally channel_convert should be compiled out, because xyz_t
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// is float32_t natively only
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float32_t x( channel_convert<float32_t>( get_color( src, x_t() ) ) );
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float32_t y( channel_convert<float32_t>( get_color( src, y_t() ) ) );
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float32_t z( channel_convert<float32_t>( get_color( src, z_t() ) ) );
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get_color(dst,red_t()) =
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channel_convert<typename color_element_type<P2, red_t>::type>(
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companding( x * 3.2404542f +
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y * -1.5371385f +
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z * -0.4985314f )
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);
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get_color(dst,green_t()) =
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channel_convert<typename color_element_type<P2, green_t>::type>(
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companding( x * -0.9692660f +
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y * 1.8760108f +
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z * 0.0415560f )
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);
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get_color(dst,blue_t()) =
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channel_convert<typename color_element_type<P2, blue_t>::type>(
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companding( x * 0.0556434f +
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y * -0.2040259f +
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z * 1.0572252f )
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);
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}
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};
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} // namespace gil
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} // namespace boost
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#endif // BOOST_GIL_EXTENSION_TOOLBOX_COLOR_SPACES_XYZ_HPP
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