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- //
- // Copyright 2012 Christian Henning
- //
- // Distributed under 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_HSV_HPP
- #define BOOST_GIL_EXTENSION_TOOLBOX_COLOR_SPACES_HSV_HPP
- #include <boost/numeric/conversion/cast.hpp>
- #include <boost/gil/color_convert.hpp>
- #include <boost/gil/typedefs.hpp>
- #include <boost/gil/detail/mp11.hpp>
- #include <algorithm>
- #include <cmath>
- namespace boost{ namespace gil {
- /// \addtogroup ColorNameModel
- /// \{
- namespace hsv_color_space
- {
- /// \brief Hue
- struct hue_t {};
- /// \brief Saturation
- struct saturation_t{};
- /// \brief Value
- struct value_t {};
- }
- /// \}
- /// \ingroup ColorSpaceModel
- using hsv_t = mp11::mp_list
- <
- hsv_color_space::hue_t,
- hsv_color_space::saturation_t,
- hsv_color_space::value_t
- >;
- /// \ingroup LayoutModel
- using hsv_layout_t = layout<hsv_t>;
- GIL_DEFINE_ALL_TYPEDEFS(32f, float32_t, hsv)
- /// \ingroup ColorConvert
- /// \brief RGB to HSV
- template <>
- struct default_color_converter_impl< rgb_t, hsv_t >
- {
- template <typename P1, typename P2>
- void operator()( const P1& src, P2& dst ) const
- {
- using namespace hsv_color_space;
- // only float32_t for hsv is supported
- float32_t temp_red = channel_convert<float32_t>( get_color( src, red_t() ));
- float32_t temp_green = channel_convert<float32_t>( get_color( src, green_t() ));
- float32_t temp_blue = channel_convert<float32_t>( get_color( src, blue_t() ));
- float32_t hue, saturation, value;
- float32_t min_color = (std::min)( temp_red, (std::min)( temp_green, temp_blue ));
- float32_t max_color = (std::max)( temp_red, (std::max)( temp_green, temp_blue ));
- value = max_color;
- float32_t diff = max_color - min_color;
- if( max_color < 0.0001f )
- {
- saturation = 0.f;
- }
- else
- {
- saturation = diff / max_color;
- }
- if( saturation < 0.0001f )
- {
- //it doesn't matter what value it has
- hue = 0.f;
- }
- else
- {
- if( (std::abs)( boost::numeric_cast<float32_t>(temp_red - max_color) ) < 0.0001f )
- {
- hue = ( temp_green - temp_blue )
- / diff;
- }
- else if( temp_green >= max_color ) // means == but >= avoids compiler warning; color is never greater than max
- {
- hue = 2.f + ( temp_blue - temp_red )
- / diff;
- }
- else
- {
- hue = 4.f + ( temp_red - temp_green )
- / diff;
- }
- //to bring it to a number between 0 and 1
- hue /= 6.f;
- if( hue < 0.f )
- {
- hue++;
- }
- }
- get_color( dst, hue_t() ) = hue;
- get_color( dst, saturation_t() ) = saturation;
- get_color( dst, value_t() ) = value;
- }
- };
- /// \ingroup ColorConvert
- /// \brief HSV to RGB
- template <>
- struct default_color_converter_impl<hsv_t,rgb_t>
- {
- template <typename P1, typename P2>
- void operator()( const P1& src, P2& dst) const
- {
- using namespace hsv_color_space;
- float32_t red, green, blue;
- //If saturation is 0, the color is a shade of gray
- if( abs( get_color( src, saturation_t() )) < 0.0001f )
- {
- // If saturation is 0, the color is a shade of gray
- red = get_color( src, value_t() );
- green = get_color( src, value_t() );
- blue = get_color( src, value_t() );
- }
- else
- {
- float32_t frac, p, q, t, h;
- uint32_t i;
- //to bring hue to a number between 0 and 6, better for the calculations
- h = get_color( src, hue_t() );
- h *= 6.f;
- i = static_cast<uint32_t>(floor(h));
- frac = h - i;
- p = get_color( src, value_t() )
- * ( 1.f - get_color( src, saturation_t() ));
- q = get_color( src, value_t() )
- * ( 1.f - ( get_color( src, saturation_t() ) * frac ));
- t = get_color( src, value_t() )
- * ( 1.f - ( get_color( src, saturation_t() ) * ( 1.f - frac )));
- switch( i )
- {
- case 0:
- {
- red = get_color( src, value_t() );
- green = t;
- blue = p;
- break;
- }
- case 1:
- {
- red = q;
- green = get_color( src, value_t() );
- blue = p;
- break;
- }
- case 2:
- {
- red = p;
- green = get_color( src, value_t() );
- blue = t;
- break;
- }
- case 3:
- {
- red = p;
- green = q;
- blue = get_color( src, value_t() );
- break;
- }
- case 4:
- {
- red = t;
- green = p;
- blue = get_color( src, value_t() );
- break;
- }
- case 5:
- {
- red = get_color( src, value_t() );
- green = p;
- blue = q;
- break;
- }
- }
- }
- get_color(dst,red_t()) =
- channel_convert<typename color_element_type< P2, red_t >::type>( red );
- get_color(dst,green_t())=
- channel_convert<typename color_element_type< P2, green_t >::type>( green );
- get_color(dst,blue_t()) =
- channel_convert<typename color_element_type< P2, blue_t >::type>( blue );
- }
- };
- } // namespace gil
- } // namespace boost
- #endif
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