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/*
Copyright 2012 Christian Henning
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_HSV_HPP
#define BOOST_GIL_EXTENSION_TOOLBOX_COLOR_SPACES_HSV_HPP
////////////////////////////////////////////////////////////////////////////////////////
/// \file hsv.hpp
/// \brief Support for HSV color space
/// \author Christian Henning \n
///
/// \date 2012 \n
///
////////////////////////////////////////////////////////////////////////////////////////
#include <boost/numeric/conversion/cast.hpp>
#include <boost/gil/typedefs.hpp>
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
typedef mpl::vector3< hsv_color_space::hue_t
, hsv_color_space::saturation_t
, hsv_color_space::value_t
> hsv_t;
/// \ingroup LayoutModel
typedef layout<hsv_t> hsv_layout_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 )
{
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 // BOOST_GIL_EXTENSION_TOOLBOX_COLOR_SPACES_HSV_HPP
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