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Diffstat (limited to 'boost/gil/extension/toolbox/color_spaces/lab.hpp')
| -rw-r--r-- | boost/gil/extension/toolbox/color_spaces/lab.hpp | 178 |
1 files changed, 178 insertions, 0 deletions
diff --git a/boost/gil/extension/toolbox/color_spaces/lab.hpp b/boost/gil/extension/toolbox/color_spaces/lab.hpp new file mode 100644 index 0000000000..140c79f763 --- /dev/null +++ b/boost/gil/extension/toolbox/color_spaces/lab.hpp @@ -0,0 +1,178 @@ +/* + Copyright 2012 Chung-Lin Wen + Use, modification and distribution are subject to the Boost Software License, + Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at + http://www.boost.org/LICENSE_1_0.txt). +*/ + +/*************************************************************************************************/ + +#ifndef BOOST_GIL_EXTENSION_TOOLBOX_COLOR_SPACES_LAB_HPP +#define BOOST_GIL_EXTENSION_TOOLBOX_COLOR_SPACES_LAB_HPP + +//////////////////////////////////////////////////////////////////////////////////////// +/// \file lab.hpp +/// \brief Support for CIE Lab color space +/// \author Chung-Lin Wen \n +/// +/// \date 2012 \n +/// +//////////////////////////////////////////////////////////////////////////////////////// + +#include <boost/gil/gil_all.hpp> // FIXME: Include what you use, not everything, even in extensions! +#include <boost/gil/extension/toolbox/color_spaces/xyz.hpp> + +namespace boost{ namespace gil { + +/// \addtogroup ColorNameModel +/// \{ +namespace lab_color_space +{ +/// \brief Luminance +struct luminance_t {}; +/// \brief a Color Component +struct a_color_opponent_t {}; +/// \brief b Color Component +struct b_color_opponent_t {}; +} +/// \} + +/// \ingroup ColorSpaceModel +typedef mpl::vector3< lab_color_space::luminance_t + , lab_color_space::a_color_opponent_t + , lab_color_space::b_color_opponent_t + > lab_t; + +/// \ingroup LayoutModel +typedef layout<lab_t> lab_layout_t; + +GIL_DEFINE_ALL_TYPEDEFS(32f, float32_t, lab) + +/// \ingroup ColorConvert +/// \brief LAB to XYZ +template <> +struct default_color_converter_impl< lab_t, xyz_t > +{ + template <typename P1, typename P2> + void operator()( const P1& src, P2& dst ) const + { + using namespace lab_color_space; + using namespace xyz_color_space; + + float32_t p = ((get_color(src, luminance_t()) + 16.f)/116.f); + + get_color(dst, y_t()) = + 1.f * powf(p, 3.f); + + get_color(dst, x_t()) = + 0.95047f * powf((p + + (get_color(src, a_color_opponent_t())/500.f) + ), 3.f); + get_color(dst, z_t()) = + 1.08883f * powf((p - + (get_color(src, b_color_opponent_t())/200.f) + ), 3.f); + } +}; + +/// \ingroup ColorConvert +/// \brief XYZ to LAB +/// \note I assume \c xyz_t +template <> +struct default_color_converter_impl< xyz_t, lab_t > +{ +private: + /// \ref http://www.brucelindbloom.com/index.html?Eqn_XYZ_to_Lab.html + BOOST_FORCEINLINE + float32_t forward_companding(float32_t value) const + { + if (value > 216.f/24389.f) + { + return powf(value, 1.f/3.f); + } + else + { + return ((24389.f/27.f * value + 16.f)/116.f); + } + } + +public: + template <typename P1, typename P2> + void operator()( const P1& src, P2& dst ) const + { + using namespace lab_color_space; + + float32_t f_y = + forward_companding( + channel_convert<float32_t>( + get_color(src, xyz_color_space::y_t()) + ) + // / 1.f + ); + + float32_t f_x = + forward_companding( + channel_convert<float32_t>( + get_color(src, xyz_color_space::x_t()) + ) + * (1.f / 0.95047f) // if the compiler is smart, it should + // precalculate this, no? + ); + + float32_t f_z = + forward_companding( + channel_convert<float32_t>( + get_color(src, xyz_color_space::z_t()) + ) + * (1.f / 1.08883f) // if the compiler is smart, it should + // precalculate this, no? + ); + + get_color(dst, luminance_t()) = + 116.f * f_y - 16.f; + + get_color(dst, a_color_opponent_t()) = + 500.f * (f_x - f_y); + + get_color(dst, b_color_opponent_t()) = + 200.f * (f_y - f_z); + } +}; + + +/// \ingroup ColorConvert +/// \brief RGB to LAB +template <> +struct default_color_converter_impl< rgb_t, lab_t > +{ + template <typename P1, typename P2> + void operator()( const P1& src, P2& dst ) const + { + using namespace lab_color_space; + + xyz32f_pixel_t xyz32f_temp_pixel; + default_color_converter_impl<rgb_t, xyz_t>()(src, xyz32f_temp_pixel); + default_color_converter_impl<xyz_t, lab_t>()(xyz32f_temp_pixel, dst); + } +}; + +/// \ingroup ColorConvert +/// \brief LAB to RGB +template <> +struct default_color_converter_impl<lab_t,rgb_t> +{ + template <typename P1, typename P2> + void operator()( const P1& src, P2& dst) const + { + using namespace lab_color_space; + + xyz32f_pixel_t xyz32f_temp_pixel; + default_color_converter_impl<lab_t, xyz_t>()(src, xyz32f_temp_pixel); + default_color_converter_impl<xyz_t, rgb_t>()(xyz32f_temp_pixel, dst); + } +}; + +} // namespace gil +} // namespace boost + +#endif // BOOST_GIL_EXTENSION_TOOLBOX_COLOR_SPACES_LAB_HPP |