ceph/src/boost/boost/gil/extension/toolbox/color_spaces/ycbcr.hpp

   1 //
   2 // Copyright 2013 Juan V. Puertos G-Cluster, Christian Henning
   3 //
   4 // Distributed under the Boost Software License, Version 1.0
   5 // See accompanying file LICENSE_1_0.txt or copy at
   6 // http://www.boost.org/LICENSE_1_0.txt
   7 //
   8 #ifndef BOOST_GIL_EXTENSION_TOOLBOX_COLOR_SPACES_YCBCR_HPP
   9 #define BOOST_GIL_EXTENSION_TOOLBOX_COLOR_SPACES_YCBCR_HPP
  10
  11 #include <boost/gil/extension/toolbox/metafunctions/get_num_bits.hpp>
  12
  13 #include <boost/gil/color_convert.hpp>
  14 #include <boost/gil.hpp> // FIXME: Include what you use!
  15 #include <boost/gil/detail/mp11.hpp>
  16
  17 #include <boost/config.hpp>
  18
  19 #include <cstdint>
  20 #include <type_traits>
  21
  22 namespace boost { namespace gil {
  23
  24 /// \addtogroup ColorNameModel
  25 /// \{
  26 namespace ycbcr_601_color_space
  27 {
  28 /// \brief Luminance
  29 struct y_t {};
  30 /// \brief Blue chrominance component
  31 struct cb_t {};
  32 /// \brief Red chrominance component
  33 struct cr_t {};
  34 }
  35
  36 namespace ycbcr_709_color_space
  37 {
  38 /// \brief Luminance
  39 struct y_t {};
  40 /// \brief Blue chrominance component
  41 struct cb_t {};
  42 /// \brief Red chrominance component
  43 struct cr_t {};
  44 }
  45 /// \}
  46
  47 /// \ingroup ColorSpaceModel
  48 using ycbcr_601__t = mp11::mp_list
  49 <
  50     ycbcr_601_color_space::y_t,
  51     ycbcr_601_color_space::cb_t,
  52     ycbcr_601_color_space::cr_t
  53 >;
  54
  55 /// \ingroup ColorSpaceModel
  56 using ycbcr_709__t = mp11::mp_list
  57 <
  58     ycbcr_709_color_space::y_t,
  59     ycbcr_709_color_space::cb_t,
  60     ycbcr_709_color_space::cr_t
  61 >;
  62
  63 /// \ingroup LayoutModel
  64 using ycbcr_601__layout_t = boost::gil::layout<ycbcr_601__t>;
  65 using ycbcr_709__layout_t = boost::gil::layout<ycbcr_709__t>;
  66
  67 //The channel depth is ALWAYS 8bits ofr YCbCr!
  68 BOOST_GIL_DEFINE_ALL_TYPEDEFS(8, uint8_t, ycbcr_601_)
  69 BOOST_GIL_DEFINE_ALL_TYPEDEFS(8, uint8_t, ycbcr_709_)
  70
  71 namespace detail {
  72
  73 // Source:boost/algorithm/clamp.hpp
  74 template<typename T>
  75 BOOST_CXX14_CONSTEXPR
  76 T const& clamp(
  77     T const& val,
  78     typename boost::mp11::mp_identity<T>::type const & lo,
  79     typename boost::mp11::mp_identity<T>::type const & hi)
  80 {
  81     // assert ( !p ( hi, lo )); // Can't assert p ( lo, hi ) b/c they might be equal
  82     auto const p = std::less<T>();
  83     return p(val, lo) ? lo : p(hi, val) ? hi : val;
  84 }
  85
  86 } // namespace detail
  87
  88 /*
  89  * 601 Source: http://en.wikipedia.org/wiki/YCbCr#ITU-R_BT.601_conversion
  90  * 709 Source: http://en.wikipedia.org/wiki/YCbCr#ITU-R_BT.709_conversion
  91  * (using values coming directly from ITU-R BT.601 recommendation)
  92  * (using values coming directly from ITU-R BT.709 recommendation)
  93  */
  94
  95 /**
  96 * @brief Convert YCbCr ITU.BT-601 to RGB.
  97 */
  98 template<>
  99 struct default_color_converter_impl<ycbcr_601__t, rgb_t>
 100 {
 101         // Note: the RGB_t channels range can be set later on by the users. We dont want to cast to uint8_t or anything here.
 102         template < typename SRCP, typename DSTP >
 103         void operator()( const SRCP& src, DSTP& dst ) const
 104         {
 105         using dst_channel_t = typename channel_type<DSTP>::type;
 106         convert(src, dst, typename std::is_same
 107             <
 108                 std::integral_constant<int, sizeof(dst_channel_t)>,
 109                 std::integral_constant<int, 1>
 110             >::type());
 111         }
 112
 113 private:
 114
 115     // optimization for bit8 channels
 116     template< typename Src_Pixel
 117             , typename Dst_Pixel
 118             >
 119     void convert( const Src_Pixel& src
 120                 ,       Dst_Pixel& dst
 121                 , std::true_type // is 8 bit channel
 122                 ) const
 123     {
 124         using namespace ycbcr_601_color_space;
 125
 126         using src_channel_t = typename channel_type<Src_Pixel>::type;
 127         using dst_channel_t = typename channel_type<Dst_Pixel>::type;
 128
 129                 src_channel_t y  = channel_convert<src_channel_t>( get_color(src,  y_t()));
 130                 src_channel_t cb = channel_convert<src_channel_t>( get_color(src, cb_t()));
 131                 src_channel_t cr = channel_convert<src_channel_t>( get_color(src, cr_t()));
 132
 133                 // The intermediate results of the formulas require at least 16bits of precission.
 134                 std::int_fast16_t c = y  - 16;
 135                 std::int_fast16_t d = cb - 128;
 136                 std::int_fast16_t e = cr - 128;
 137                 std::int_fast16_t red   = detail::clamp((( 298 * c + 409 * e + 128) >> 8), 0, 255);
 138                 std::int_fast16_t green = detail::clamp((( 298 * c - 100 * d - 208 * e + 128) >> 8), 0, 255);
 139                 std::int_fast16_t blue  = detail::clamp((( 298 * c + 516 * d + 128) >> 8), 0, 255);
 140
 141                 get_color( dst,  red_t() )  = (dst_channel_t) red;
 142                 get_color( dst, green_t() ) = (dst_channel_t) green;
 143                 get_color( dst,  blue_t() ) = (dst_channel_t) blue;
 144     }
 145
 146
 147     template< typename Src_Pixel
 148             , typename Dst_Pixel
 149             >
 150     void convert( const Src_Pixel& src
 151                 ,       Dst_Pixel& dst
 152                 , std::false_type // is 8 bit channel
 153                 ) const
 154     {
 155         using namespace ycbcr_601_color_space;
 156
 157         using dst_channel_t = typename channel_type<Dst_Pixel>::type;
 158
 159         double  y = get_color( src,  y_t() );
 160         double cb = get_color( src, cb_t() );
 161         double cr = get_color( src, cr_t() );
 162
 163         get_color(dst, red_t()) = static_cast<dst_channel_t>(
 164             detail::clamp(1.6438 * (y - 16.0) + 1.5960 * (cr -128.0), 0.0, 255.0));
 165
 166         get_color(dst, green_t()) = static_cast<dst_channel_t>(
 167             detail::clamp(1.6438 * (y - 16.0) - 0.3917 * (cb - 128.0) + 0.8129 * (cr -128.0), 0.0, 255.0));
 168
 169         get_color(dst, blue_t()) = static_cast<dst_channel_t>(
 170             detail::clamp(1.6438 * ( y - 16.0 ) - 2.0172 * ( cb -128.0 ), 0.0, 255.0));
 171     }
 172 };
 173
 174 /*
 175  * Source: http://en.wikipedia.org/wiki/YCbCr#ITU-R_BT.601_conversion
 176  * digital Y'CbCr derived from digital R'dG'dB'd 8 bits per sample, each using the full range.
 177  * with NO footroom wither headroom.
 178  */
 179 /**
 180 * @brief Convert RGB to YCbCr ITU.BT-601.
 181 */
 182 template<>
 183 struct default_color_converter_impl<rgb_t, ycbcr_601__t>
 184 {
 185         template < typename SRCP, typename DSTP >
 186         void operator()( const SRCP& src, DSTP& dst ) const
 187         {
 188         using namespace ycbcr_601_color_space;
 189
 190         using src_channel_t = typename channel_type<SRCP>::type;
 191         using dst_channel_t = typename channel_type<DSTP>::type;
 192
 193                 src_channel_t red   = channel_convert<src_channel_t>( get_color(src,   red_t()));
 194                 src_channel_t green = channel_convert<src_channel_t>( get_color(src, green_t()));
 195                 src_channel_t blue  = channel_convert<src_channel_t>( get_color(src,  blue_t()));
 196
 197                 double  y =  16.0 + 0.2567 * red  + 0.5041 * green + 0.0979 * blue;
 198                 double cb = 128.0 - 0.1482 * red  - 0.2909 * green + 0.4392 * blue;
 199                 double cr = 128.0 + 0.4392 * red  - 0.3677 * green - 0.0714 * blue;
 200
 201                 get_color( dst,  y_t() ) = (dst_channel_t)  y;
 202                 get_color( dst, cb_t() ) = (dst_channel_t) cb;
 203                 get_color( dst, cr_t() ) = (dst_channel_t) cr;
 204         }
 205 };
 206
 207 /**
 208 * @brief Convert RGB to YCbCr ITU.BT-709.
 209 */
 210 template<>
 211 struct default_color_converter_impl<rgb_t, ycbcr_709__t>
 212 {
 213         template < typename SRCP, typename DSTP >
 214         void operator()( const SRCP& src, DSTP& dst ) const
 215         {
 216         using namespace ycbcr_709_color_space;
 217
 218         using src_channel_t = typename channel_type<SRCP>::type;
 219         using dst_channel_t = typename channel_type<DSTP>::type;
 220
 221                 src_channel_t red   = channel_convert<src_channel_t>( get_color(src,   red_t()));
 222                 src_channel_t green = channel_convert<src_channel_t>( get_color(src, green_t()));
 223                 src_channel_t blue  = channel_convert<src_channel_t>( get_color(src,  blue_t()));
 224
 225                 double  y =            0.299 * red  +    0.587 * green +    0.114 * blue;
 226                 double cb = 128.0 - 0.168736 * red  - 0.331264 * green +      0.5 * blue;
 227                 double cr = 128.0 +      0.5 * red  - 0.418688 * green - 0.081312 * blue;
 228
 229                 get_color( dst,  y_t() ) = (dst_channel_t)  y;
 230                 get_color( dst, cb_t() ) = (dst_channel_t) cb;
 231                 get_color( dst, cr_t() ) = (dst_channel_t) cr;
 232         }
 233 };
 234
 235 /**
 236 * @brief Convert RGB to YCbCr ITU.BT-709.
 237 */
 238 template<>
 239 struct default_color_converter_impl<ycbcr_709__t, rgb_t>
 240 {
 241         template < typename SRCP, typename DSTP >
 242         void operator()( const SRCP& src, DSTP& dst ) const
 243         {
 244         using namespace ycbcr_709_color_space;
 245
 246         using src_channel_t = typename channel_type<SRCP>::type;
 247         using dst_channel_t = typename channel_type<DSTP>::type;
 248
 249                 src_channel_t y           = channel_convert<src_channel_t>( get_color(src,  y_t())       );
 250                 src_channel_t cb_clipped  = channel_convert<src_channel_t>( get_color(src, cb_t()) - 128 );
 251                 src_channel_t cr_clipped  = channel_convert<src_channel_t>( get_color(src, cr_t()) - 128 );
 252
 253                 double   red =   y                        +   1.042 * cr_clipped;
 254                 double green =   y - 0.34414 * cb_clipped - 0.71414 * cr_clipped;
 255                 double  blue =   y +   1.772 * cb_clipped;
 256
 257                 get_color( dst,   red_t() ) = (dst_channel_t)   red;
 258                 get_color( dst, green_t() ) = (dst_channel_t) green;
 259                 get_color( dst,  blue_t() ) = (dst_channel_t)  blue;
 260         }
 261 };
 262
 263 } // namespace gil
 264 } // namespace boost
 265
 266 #endif