boost/gil/packed_pixel.hpp

   1 /*
   2     Copyright 2005-2007 Adobe Systems Incorporated
   3
   4     Use, modification and distribution are subject to the Boost Software License,
   5     Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
   6     http://www.boost.org/LICENSE_1_0.txt).
   7
   8     See http://opensource.adobe.com/gil for most recent version including documentation.
   9 */
  10
  11 /*************************************************************************************************/
  12
  13 #ifndef GIL_PACKED_PIXEL_H
  14 #define GIL_PACKED_PIXEL_H
  15
  16 ////////////////////////////////////////////////////////////////////////////////////////
  17 /// \file
  18 /// \brief A model of a heterogeneous pixel whose channels are bit ranges. For example 16-bit RGB in '565' format
  19 /// \author Lubomir Bourdev and Hailin Jin \n
  20 ///         Adobe Systems Incorporated
  21 /// \date   2005-2009 \n Last updated on February 20, 2009
  22 ///
  23 ////////////////////////////////////////////////////////////////////////////////////////
  24
  25 #include <functional>
  26 #include <boost/utility/enable_if.hpp>
  27 #include <boost/mpl/bool.hpp>
  28 #include <boost/mpl/front.hpp>
  29 #include "gil_config.hpp"
  30 #include "pixel.hpp"
  31
  32 namespace boost { namespace gil {
  33
  34 /// \defgroup ColorBaseModelPackedPixel packed_pixel
  35 /// \ingroup ColorBaseModel
  36 /// \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.
  37
  38 /**
  39 \defgroup PixelModelPackedPixel packed_pixel
  40 \ingroup PixelModel
  41 \brief A heterogeneous pixel used to represent packed pixels with non-byte-aligned channels. Models PixelValueConcept
  42
  43 Example:
  44 \code
  45 typedef packed_pixel_type<uint16_t, mpl::vector3_c<unsigned,5,6,5>, rgb_layout_t>::type rgb565_pixel_t;
  46 BOOST_STATIC_ASSERT((sizeof(rgb565_pixel_t)==2));
  47
  48 rgb565_pixel_t r565;
  49 get_color(r565,red_t())   = 31;
  50 get_color(r565,green_t()) = 63;
  51 get_color(r565,blue_t())  = 31;
  52 assert(r565 == rgb565_pixel_t((uint16_t)0xFFFF));
  53 \endcode
  54 */
  55
  56 /// \ingroup ColorBaseModelPackedPixel PixelModelPackedPixel PixelBasedModel
  57 /// \brief Heterogeneous pixel value whose channel references can be constructed from the pixel bitfield and their index. Models ColorBaseValueConcept, PixelValueConcept, PixelBasedConcept
  58 /// Typical use for this is a model of a packed pixel (like 565 RGB)
  59 template <typename BitField,      // A type that holds the bits of the pixel. Typically an integral type, like boost::uint16_t
  60           typename ChannelRefVec, // An MPL vector whose elements are packed channels. They must be constructible from BitField. GIL uses packed_channel_reference
  61           typename Layout>        // Layout defining the color space and ordering of the channels. Example value: rgb_layout_t
  62 struct packed_pixel {
  63     BitField _bitfield;
  64
  65     typedef Layout                layout_t;
  66     typedef packed_pixel          value_type;
  67     typedef value_type&           reference;
  68     typedef const value_type&     const_reference;
  69
  70     BOOST_STATIC_CONSTANT(bool, is_mutable = channel_traits<typename mpl::front<ChannelRefVec>::type>::is_mutable);
  71
  72     packed_pixel(){}
  73     explicit packed_pixel(const BitField& bitfield) : _bitfield(bitfield) {}
  74
  75     // Construct from another compatible pixel type
  76     packed_pixel(const packed_pixel& p) : _bitfield(p._bitfield) {}
  77     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); }
  78     packed_pixel(int chan0, int chan1) : _bitfield(0) {
  79         BOOST_STATIC_ASSERT((num_channels<packed_pixel>::value==2));
  80         at_c<0>(*this)=chan0; at_c<1>(*this)=chan1;
  81     }
  82     packed_pixel(int chan0, int chan1, int chan2) : _bitfield(0) {
  83         BOOST_STATIC_ASSERT((num_channels<packed_pixel>::value==3));
  84         at_c<0>(*this)=chan0; at_c<1>(*this)=chan1; at_c<2>(*this)=chan2;
  85     }
  86     packed_pixel(int chan0, int chan1, int chan2, int chan3) : _bitfield(0) {
  87         BOOST_STATIC_ASSERT((num_channels<packed_pixel>::value==4));
  88         at_c<0>(*this)=chan0; at_c<1>(*this)=chan1; at_c<2>(*this)=chan2; at_c<3>(*this)=chan3;
  89     }
  90     packed_pixel(int chan0, int chan1, int chan2, int chan3, int chan4) : _bitfield(0) {
  91         BOOST_STATIC_ASSERT((num_channels<packed_pixel>::value==5));
  92         at_c<0>(*this)=chan0; at_c<1>(*this)=chan1; at_c<2>(*this)=chan2; at_c<3>(*this)=chan3; at_c<4>(*this)=chan4;
  93     }
  94
  95     packed_pixel& operator=(const packed_pixel& p)     { _bitfield=p._bitfield; return *this; }
  96
  97     template <typename P> packed_pixel& operator=(const P& p)        { assign(p, mpl::bool_<is_pixel<P>::value>()); return *this; }
  98     template <typename P> bool          operator==(const P& p) const { return equal(p, mpl::bool_<is_pixel<P>::value>()); }
  99
 100     template <typename P> bool operator!=(const P& p) const { return !(*this==p); }
 101
 102 private:
 103     template <typename Pixel> static void check_compatible() { gil_function_requires<PixelsCompatibleConcept<Pixel,packed_pixel> >(); }
 104     template <typename Pixel> void assign(const Pixel& p, mpl::true_)       { check_compatible<Pixel>(); static_copy(p,*this); }
 105     template <typename Pixel> bool  equal(const Pixel& p, mpl::true_) const { check_compatible<Pixel>(); return static_equal(*this,p); }
 106
 107 // Support for assignment/equality comparison of a channel with a grayscale pixel
 108     static void check_gray() {  BOOST_STATIC_ASSERT((is_same<typename Layout::color_space_t, gray_t>::value)); }
 109     template <typename Channel> void assign(const Channel& chan, mpl::false_)       { check_gray(); at_c<0>(*this)=chan; }
 110     template <typename Channel> bool equal (const Channel& chan, mpl::false_) const { check_gray(); return at_c<0>(*this)==chan; }
 111 public:
 112     packed_pixel&  operator= (int chan)       { check_gray(); at_c<0>(*this)=chan; return *this; }
 113     bool           operator==(int chan) const { check_gray(); return at_c<0>(*this)==chan; }
 114 };
 115
 116 /////////////////////////////
 117 //  ColorBasedConcept
 118 /////////////////////////////
 119
 120 template <typename BitField, typename ChannelRefVec, typename Layout, int K>
 121 struct kth_element_type<packed_pixel<BitField,ChannelRefVec,Layout>,K> : public mpl::at_c<ChannelRefVec,K> {};
 122
 123 template <typename BitField, typename ChannelRefVec, typename Layout, int K>
 124 struct kth_element_reference_type<packed_pixel<BitField,ChannelRefVec,Layout>,K> : public mpl::at_c<ChannelRefVec,K> {};
 125
 126 template <typename BitField, typename ChannelRefVec, typename Layout, int K>
 127 struct kth_element_const_reference_type<packed_pixel<BitField,ChannelRefVec,Layout>,K> {
 128     typedef typename channel_traits<typename mpl::at_c<ChannelRefVec,K>::type>::const_reference type;
 129 };
 130
 131 template <int K, typename P, typename C, typename L> inline
 132 typename kth_element_reference_type<packed_pixel<P,C,L>, K>::type
 133 at_c(packed_pixel<P,C,L>& p) {
 134     return typename kth_element_reference_type<packed_pixel<P,C,L>, K>::type(&p._bitfield);
 135 }
 136
 137 template <int K, typename P, typename C, typename L> inline
 138 typename kth_element_const_reference_type<packed_pixel<P,C,L>, K>::type
 139 at_c(const packed_pixel<P,C,L>& p) {
 140     return typename kth_element_const_reference_type<packed_pixel<P,C,L>, K>::type(&p._bitfield);
 141 }
 142
 143 /////////////////////////////
 144 //  PixelConcept
 145 /////////////////////////////
 146
 147 // Metafunction predicate that flags packed_pixel as a model of PixelConcept. Required by PixelConcept
 148 template <typename BitField, typename ChannelRefVec, typename Layout>
 149 struct is_pixel<packed_pixel<BitField,ChannelRefVec,Layout> > : public mpl::true_{};
 150
 151 /////////////////////////////
 152 //  PixelBasedConcept
 153 /////////////////////////////
 154
 155 template <typename P, typename C, typename Layout>
 156 struct color_space_type<packed_pixel<P,C,Layout> > {
 157     typedef typename Layout::color_space_t type;
 158 };
 159
 160 template <typename P, typename C, typename Layout>
 161 struct channel_mapping_type<packed_pixel<P,C,Layout> > {
 162     typedef typename Layout::channel_mapping_t type;
 163 };
 164
 165 template <typename P, typename C, typename Layout>
 166 struct is_planar<packed_pixel<P,C,Layout> > : mpl::false_ {};
 167
 168
 169 ////////////////////////////////////////////////////////////////////////////////
 170 ///
 171 /// Support for interleaved iterators over packed pixel
 172 ///
 173 ////////////////////////////////////////////////////////////////////////////////
 174
 175 /// \defgroup PixelIteratorModelPackedInterleavedPtr Pointer to packed_pixel<P,CR,Layout>
 176 /// \ingroup PixelIteratorModel
 177 /// \brief Iterators over interleaved pixels.
 178 /// The pointer packed_pixel<P,CR,Layout>* is used as an iterator over interleaved pixels of packed format. Models PixelIteratorConcept, HasDynamicXStepTypeConcept, MemoryBasedIteratorConcept
 179
 180 template <typename P, typename C, typename L>
 181 struct iterator_is_mutable<packed_pixel<P,C,L>*> : public mpl::bool_<packed_pixel<P,C,L>::is_mutable> {};
 182 template <typename P, typename C, typename L>
 183 struct iterator_is_mutable<const packed_pixel<P,C,L>*> : public mpl::false_ {};
 184
 185
 186
 187 } }  // namespace boost::gil
 188
 189 namespace boost {
 190     template <typename P, typename C, typename L>
 191     struct has_trivial_constructor<gil::packed_pixel<P,C,L> > : public has_trivial_constructor<P> {};
 192 }
 193 #endif