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# packed_pixel.hpp

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    00001 /*
    00002     Copyright 2005-2007 Adobe Systems Incorporated
    00003
    00004     Use, modification and distribution are subject to the Boost Software License,
    00005     Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
    00006     http://www.boost.org/LICENSE_1_0.txt).
    00007
    00008     See http://opensource.adobe.com/gil for most recent version including documentation.
    00009 */
    00010
    00011 /*************************************************************************************************/
    00012
    00013 #ifndef GIL_PACKED_PIXEL_H
    00014 #define GIL_PACKED_PIXEL_H
    00015
    00024
    00025 #include <functional>
    00026 #include <boost/utility/enable_if.hpp>
    00027 #include <boost/mpl/bool.hpp>
    00028 #include <boost/mpl/front.hpp>
    00029 #include "gil_config.hpp"
    00030 #include "pixel.hpp"
    00031
    00032 namespace boost { namespace gil {
    00033
    00037
    00056
    00057
    00058
    00059 template <typename BitField,      // A type that holds the bits of the pixel. Typically an integral type, like boost::uint16_t
    00060           typename ChannelRefVec, // An MPL vector whose elements are packed channels. They must be constructible from BitField. GIL uses packed_channel_reference
    00061           typename Layout>        // Layout defining the color space and ordering of the channels. Example value: rgb_layout_t
    00062 struct packed_pixel {
    00063     BitField _bitfield;
    00064
    00065     typedef Layout                layout_t;
    00066     typedef packed_pixel          value_type;
    00067     typedef value_type&           reference;
    00068     typedef const value_type&     const_reference;
    00069
    00070     BOOST_STATIC_CONSTANT(bool, is_mutable = channel_traits<typename mpl::front<ChannelRefVec>::type>::is_mutable);
    00071
    00072     packed_pixel(){}
    00073     explicit packed_pixel(const BitField& bitfield) : _bitfield(bitfield) {}
    00074
    00075     // Construct from another compatible pixel type
    00076     packed_pixel(const packed_pixel& p) : _bitfield(p._bitfield) {}
    00077     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); }
    00078     packed_pixel(int chan0, int chan1) : _bitfield(0) {
    00079         BOOST_STATIC_ASSERT((num_channels<packed_pixel>::value==2));
    00080         at_c<0>(*this)=chan0; at_c<1>(*this)=chan1;
    00081     }
    00082     packed_pixel(int chan0, int chan1, int chan2) : _bitfield(0) {
    00083         BOOST_STATIC_ASSERT((num_channels<packed_pixel>::value==3));
    00084         at_c<0>(*this)=chan0; at_c<1>(*this)=chan1; at_c<2>(*this)=chan2;
    00085     }
    00086     packed_pixel(int chan0, int chan1, int chan2, int chan3) : _bitfield(0) {
    00087         BOOST_STATIC_ASSERT((num_channels<packed_pixel>::value==4));
    00088         at_c<0>(*this)=chan0; at_c<1>(*this)=chan1; at_c<2>(*this)=chan2; at_c<3>(*this)=chan3;
    00089     }
    00090     packed_pixel(int chan0, int chan1, int chan2, int chan3, int chan4) : _bitfield(0) {
    00091         BOOST_STATIC_ASSERT((num_channels<packed_pixel>::value==5));
    00092         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;
    00093     }
    00094
    00095     packed_pixel& operator=(const packed_pixel& p)     { _bitfield=p._bitfield; return *this; }
    00096
    00097     template <typename P> packed_pixel& operator=(const P& p)        { assign(p, mpl::bool_<is_pixel<P>::value>()); return *this; }
    00098     template <typename P> bool          operator==(const P& p) const { return equal(p, mpl::bool_<is_pixel<P>::value>()); }
    00099
    00100     template <typename P> bool operator!=(const P& p) const { return !(*this==p); }
    00101
    00102 private:
    00103     template <typename Pixel> static void check_compatible() { gil_function_requires<PixelsCompatibleConcept<Pixel,packed_pixel> >(); }
    00104     template <typename Pixel> void assign(const Pixel& p, mpl::true_)       { check_compatible<Pixel>(); static_copy(p,*this); }
    00105     template <typename Pixel> bool  equal(const Pixel& p, mpl::true_) const { check_compatible<Pixel>(); return static_equal(*this,p); }
    00106
    00107 // Support for assignment/equality comparison of a channel with a grayscale pixel
    00108     static void check_gray() {  BOOST_STATIC_ASSERT((is_same<typename Layout::color_space_t, gray_t>::value)); }
    00109     template <typename Channel> void assign(const Channel& chan, mpl::false_)       { check_gray(); at_c<0>(*this)=chan; }
    00110     template <typename Channel> bool equal (const Channel& chan, mpl::false_) const { check_gray(); return at_c<0>(*this)==chan; }
    00111 public:
    00112     packed_pixel&  operator= (int chan)       { check_gray(); at_c<0>(*this)=chan; return *this; }
    00113     bool           operator==(int chan) const { check_gray(); return at_c<0>(*this)==chan; }
    00114 };
    00115
    00117 //  ColorBasedConcept
    00119
    00120 template <typename BitField, typename ChannelRefVec, typename Layout, int K>
    00121 struct kth_element_type<packed_pixel<BitField,ChannelRefVec,Layout>,K> : public mpl::at_c<ChannelRefVec,K> {};
    00122
    00123 template <typename BitField, typename ChannelRefVec, typename Layout, int K>
    00124 struct kth_element_reference_type<packed_pixel<BitField,ChannelRefVec,Layout>,K> : public mpl::at_c<ChannelRefVec,K> {};
    00125
    00126 template <typename BitField, typename ChannelRefVec, typename Layout, int K>
    00127 struct kth_element_const_reference_type<packed_pixel<BitField,ChannelRefVec,Layout>,K> {
    00128     typedef typename channel_traits<typename mpl::at_c<ChannelRefVec,K>::type>::const_reference type;
    00129 };
    00130
    00131 template <int K, typename P, typename C, typename L> inline
    00132 typename kth_element_reference_type<packed_pixel<P,C,L>, K>::type
    00133 at_c(packed_pixel<P,C,L>& p) {
    00134     return typename kth_element_reference_type<packed_pixel<P,C,L>, K>::type(&p._bitfield);
    00135 }
    00136
    00137 template <int K, typename P, typename C, typename L> inline
    00138 typename kth_element_const_reference_type<packed_pixel<P,C,L>, K>::type
    00139 at_c(const packed_pixel<P,C,L>& p) {
    00140     return typename kth_element_const_reference_type<packed_pixel<P,C,L>, K>::type(&p._bitfield);
    00141 }
    00142
    00144 //  PixelConcept
    00146
    00147 // Metafunction predicate that flags packed_pixel as a model of PixelConcept. Required by PixelConcept
    00148 template <typename BitField, typename ChannelRefVec, typename Layout>
    00149 struct is_pixel<packed_pixel<BitField,ChannelRefVec,Layout> > : public mpl::true_{};
    00150
    00152 //  PixelBasedConcept
    00154
    00155 template <typename P, typename C, typename Layout>
    00156 struct color_space_type<packed_pixel<P,C,Layout> > {
    00157     typedef typename Layout::color_space_t type;
    00158 };
    00159
    00160 template <typename P, typename C, typename Layout>
    00161 struct channel_mapping_type<packed_pixel<P,C,Layout> > {
    00162     typedef typename Layout::channel_mapping_t type;
    00163 };
    00164
    00165 template <typename P, typename C, typename Layout>
    00166 struct is_planar<packed_pixel<P,C,Layout> > : mpl::false_ {};
    00167
    00168
    00174
    00179
    00180 template <typename P, typename C, typename L>
    00181 struct iterator_is_mutable<packed_pixel<P,C,L>*> : public mpl::bool_<packed_pixel<P,C,L>::is_mutable> {};
    00182 template <typename P, typename C, typename L>
    00183 struct iterator_is_mutable<const packed_pixel<P,C,L>*> : public mpl::false_ {};
    00184
    00185
    00186
    00187 } }  // namespace boost::gil
    00188
    00189 namespace boost {
    00190     template <typename P, typename C, typename L>
    00191     struct has_trivial_constructor<gil::packed_pixel<P,C,L> > : public has_trivial_constructor<P> {};
    00192 }
    00193 #endif