text: /*
      Copyright 2005-2007 Adobe Systems Incorporated
     
      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).
  
      See http://opensource.adobe.com/gil for most recent version including documentation.
  */
  
  /*************************************************************************************************/
  
  #ifndef GIL_PACKED_PIXEL_H
  #define GIL_PACKED_PIXEL_H
  
  ////////////////////////////////////////////////////////////////////////////////////////
  /// \file               
  /// \brief A model of a heterogeneous pixel whose channels are bit ranges. For example 16-bit RGB in '565' format
  /// \author Lubomir Bourdev and Hailin Jin \n
  ///         Adobe Systems Incorporated
  /// \date   2005-2009 \n Last updated on February 20, 2009
  ///
  ////////////////////////////////////////////////////////////////////////////////////////
  
  #include <functional>
  #include <boost/utility/enable_if.hpp>
  #include <boost/mpl/bool.hpp>
  #include <boost/mpl/front.hpp>
  #include "gil_config.hpp"
  #include "pixel.hpp"
  
  namespace boost { namespace gil {
  
  /// \defgroup ColorBaseModelPackedPixel packed_pixel 
  /// \ingroup ColorBaseModel
  /// \brief A heterogeneous color base whose elements are reference proxies to channels in a pixel. Models ColorBaseValueConcept. This class is used to model packed pixels, such as 16-bit packed RGB.
  
  /**
  \defgroup PixelModelPackedPixel packed_pixel 
  \ingroup PixelModel
  \brief A heterogeneous pixel used to represent packed pixels with non-byte-aligned channels. Models PixelValueConcept
  
  Example:
  \code
  typedef packed_pixel_type<uint16_t, mpl::vector3_c<unsigned,5,6,5>, rgb_layout_t>::type rgb565_pixel_t;
  BOOST_STATIC_ASSERT((sizeof(rgb565_pixel_t)==2));
  
  rgb565_pixel_t r565;
  get_color(r565,red_t())   = 31;
  get_color(r565,green_t()) = 63;
  get_color(r565,blue_t())  = 31;
  assert(r565 == rgb565_pixel_t((uint16_t)0xFFFF));    
  \endcode
  */
  
  /// \ingroup ColorBaseModelPackedPixel PixelModelPackedPixel PixelBasedModel
  /// \brief Heterogeneous pixel value whose channel references can be constructed from the pixel bitfield and their index. Models ColorBaseValueConcept, PixelValueConcept, PixelBasedConcept
  /// Typical use for this is a model of a packed pixel (like 565 RGB)
  template <typename BitField,      // A type that holds the bits of the pixel. Typically an integral type, like boost::uint16_t
            typename ChannelRefVec, // An MPL vector whose elements are packed channels. They must be constructible from BitField. GIL uses packed_channel_reference
            typename Layout>        // Layout defining the color space and ordering of the channels. Example value: rgb_layout_t
  struct packed_pixel {
      BitField _bitfield;
  
      typedef Layout                layout_t;
      typedef packed_pixel          value_type;
      typedef value_type&           reference;
      typedef const value_type&     const_reference;
  
      BOOST_STATIC_CONSTANT(bool, is_mutable = channel_traits<typename mpl::front<ChannelRefVec>::type>::is_mutable);
  
      packed_pixel(){}
      explicit packed_pixel(const BitField& bitfield) : _bitfield(bitfield) {}
  
      // Construct from another compatible pixel type
      packed_pixel(const packed_pixel& p) : _bitfield(p._bitfield) {}
      template <typename P> packed_pixel(const P& p, typename enable_if_c<is_pixel<P>::value>::type* d=0)            { check_compatible<P>(); static_copy(p,*this); }   
      packed_pixel(int chan0, int chan1) : _bitfield(0) { 
          BOOST_STATIC_ASSERT((num_channels<packed_pixel>::value==2)); 
          at_c<0>(*this)=chan0; at_c<1>(*this)=chan1; 
      } 
      packed_pixel(int chan0, int chan1, int chan2) : _bitfield(0) { 
          BOOST_STATIC_ASSERT((num_channels<packed_pixel>::value==3)); 
          gil::at_c<0>(*this)=chan0; gil::at_c<1>(*this)=chan1; gil::at_c<2>(*this)=chan2; 
      } 
      packed_pixel(int chan0, int chan1, int chan2, int chan3) : _bitfield(0) { 
          BOOST_STATIC_ASSERT((num_channels<packed_pixel>::value==4)); 
          gil::at_c<0>(*this)=chan0; gil::at_c<1>(*this)=chan1; gil::at_c<2>(*this)=chan2; gil::at_c<3>(*this)=chan3; 
      } 
      packed_pixel(int chan0, int chan1, int chan2, int chan3, int chan4) : _bitfield(0) { 
          BOOST_STATIC_ASSERT((num_channels<packed_pixel>::value==5)); 
          gil::at_c<0>(*this)=chan0; gil::at_c<1>(*this)=chan1; gil::at_c<2>(*this)=chan2; gil::at_c<3>(*this)=chan3; gil::at_c<4>(*this)=chan4;
      } 
  
      packed_pixel& operator=(const packed_pixel& p)     { _bitfield=p._bitfield; return *this; }
  
      template <typename P> packed_pixel& operator=(const P& p)        { assign(p, mpl::bool_<is_pixel<P>::value>()); return *this; } 
      template <typename P> bool          operator==(const P& p) const { return equal(p, mpl::bool_<is_pixel<P>::value>()); } 
  
      template <typename P> bool operator!=(const P& p) const { return !(*this==p); }
  
  private:
      template <typename Pixel> static void check_compatible() { gil_function_requires<PixelsCompatibleConcept<Pixel,packed_pixel> >(); }
      template <typename Pixel> void assign(const Pixel& p, mpl::true_)       { check_compatible<Pixel>(); static_copy(p,*this); } 
      template <typename Pixel> bool  equal(const Pixel& p, mpl::true_) const { check_compatible<Pixel>(); return static_equal(*this,p); } 
  
  // Support for assignment/equality comparison of a channel with a grayscale pixel
      static void check_gray() {  BOOST_STATIC_ASSERT((is_same<typename Layout::color_space_t, gray_t>::value)); }
      template <typename Channel> void assign(const Channel& chan, mpl::false_)       { check_gray(); at_c<0>(*this)=chan; }
      template <typename Channel> bool equal (const Channel& chan, mpl::false_) const { check_gray(); return at_c<0>(*this)==chan; }
  public:
      packed_pixel&  operator= (int chan)       { check_gray(); at_c<0>(*this)=chan; return *this; }
      bool           operator==(int chan) const { check_gray(); return at_c<0>(*this)==chan; }
  };
  
  /////////////////////////////
  //  ColorBasedConcept
  /////////////////////////////
  
  template <typename BitField, typename ChannelRefVec, typename Layout, int K>  
  struct kth_element_type<packed_pixel<BitField,ChannelRefVec,Layout>,K> : public mpl::at_c<ChannelRefVec,K> {};
  
  template <typename BitField, typename ChannelRefVec, typename Layout, int K>  
  struct kth_element_reference_type<packed_pixel<BitField,ChannelRefVec,Layout>,K> : public mpl::at_c<ChannelRefVec,K> {};
  
  template <typename BitField, typename ChannelRefVec, typename Layout, int K>  
  struct kth_element_const_reference_type<packed_pixel<BitField,ChannelRefVec,Layout>,K> {
      typedef typename channel_traits<typename mpl::at_c<ChannelRefVec,K>::type>::const_reference type;
  };
  
  template <int K, typename P, typename C, typename L> inline
  typename kth_element_reference_type<packed_pixel<P,C,L>, K>::type 
  at_c(packed_pixel<P,C,L>& p) { 
      return typename kth_element_reference_type<packed_pixel<P,C,L>, K>::type(&p._bitfield); 
  }
  
  template <int K, typename P, typename C, typename L> inline
  typename kth_element_const_reference_type<packed_pixel<P,C,L>, K>::type 
  at_c(const packed_pixel<P,C,L>& p) { 
      return typename kth_element_const_reference_type<packed_pixel<P,C,L>, K>::type(&p._bitfield);
  }
  
  /////////////////////////////
  //  PixelConcept
  /////////////////////////////
  
  // Metafunction predicate that flags packed_pixel as a model of PixelConcept. Required by PixelConcept
  template <typename BitField, typename ChannelRefVec, typename Layout>  
  struct is_pixel<packed_pixel<BitField,ChannelRefVec,Layout> > : public mpl::true_{};
  
  /////////////////////////////
  //  PixelBasedConcept
  /////////////////////////////
  
  template <typename P, typename C, typename Layout>
  struct color_space_type<packed_pixel<P,C,Layout> > {
      typedef typename Layout::color_space_t type;
  }; 
  
  template <typename P, typename C, typename Layout>
  struct channel_mapping_type<packed_pixel<P,C,Layout> > {
      typedef typename Layout::channel_mapping_t type;
  }; 
  
  template <typename P, typename C, typename Layout>
  struct is_planar<packed_pixel<P,C,Layout> > : mpl::false_ {}; 
  
  
  ////////////////////////////////////////////////////////////////////////////////
  ///
  /// Support for interleaved iterators over packed pixel
  ///
  ////////////////////////////////////////////////////////////////////////////////
  
  /// \defgroup PixelIteratorModelPackedInterleavedPtr Pointer to packed_pixel<P,CR,Layout>
  /// \ingroup PixelIteratorModel
  /// \brief Iterators over interleaved pixels.
  /// The pointer packed_pixel<P,CR,Layout>* is used as an iterator over interleaved pixels of packed format. Models PixelIteratorConcept, HasDynamicXStepTypeConcept, MemoryBasedIteratorConcept
  
  template <typename P, typename C, typename L>  
  struct iterator_is_mutable<packed_pixel<P,C,L>*> : public mpl::bool_<packed_pixel<P,C,L>::is_mutable> {};
  template <typename P, typename C, typename L>  
  struct iterator_is_mutable<const packed_pixel<P,C,L>*> : public mpl::false_ {};
  
  
  
  } }  // namespace boost::gil
  
  namespace boost {
      template <typename P, typename C, typename L>
      struct has_trivial_constructor<gil::packed_pixel<P,C,L> > : public has_trivial_constructor<P> {};
  }
  #endif
  