Chris@16: /*
Chris@16:     Copyright 2005-2007 Adobe Systems Incorporated
Chris@16:    
Chris@16:     Use, modification and distribution are subject to the Boost Software License,
Chris@16:     Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
Chris@16:     http://www.boost.org/LICENSE_1_0.txt).
Chris@16: 
Chris@16:     See http://stlab.adobe.com/gil for most recent version including documentation.
Chris@16: */
Chris@16: 
Chris@16: /*************************************************************************************************/
Chris@16: 
Chris@16: #ifndef GIL_BIT_ALIGNED_PIXEL_REFERENCE_HPP
Chris@16: #define GIL_BIT_ALIGNED_PIXEL_REFERENCE_HPP
Chris@16: 
Chris@16: ////////////////////////////////////////////////////////////////////////////////////////
Chris@16: /// \file               
Chris@16: /// \brief A model of a heterogeneous pixel that is not byte aligned. Examples are bitmap (1-bit pixels) or 6-bit RGB (222)
Chris@16: /// \author Lubomir Bourdev and Hailin Jin \n
Chris@16: ///         Adobe Systems Incorporated
Chris@16: /// \date   2005-2007 \n Last updated on September 28, 2006
Chris@16: ///
Chris@16: ////////////////////////////////////////////////////////////////////////////////////////
Chris@16: 
Chris@16: #include <functional>
Chris@16: #include <boost/mpl/accumulate.hpp>
Chris@16: #include <boost/mpl/at.hpp>
Chris@16: #include <boost/mpl/bool.hpp>
Chris@16: #include <boost/mpl/if.hpp>
Chris@16: #include <boost/mpl/plus.hpp>
Chris@16: #include <boost/mpl/push_back.hpp>
Chris@16: #include <boost/mpl/vector.hpp>
Chris@16: #include "gil_config.hpp"
Chris@16: #include "pixel.hpp"
Chris@16: #include "channel.hpp"
Chris@16: 
Chris@16: namespace boost { namespace gil {
Chris@16: 
Chris@16: /////////////////////////////
Chris@16: //  bit_range
Chris@16: //
Chris@16: //  Represents a range of bits that can span multiple consecutive bytes. The range has a size fixed at compile time, but the offset is specified at run time.
Chris@16: /////////////////////////////
Chris@16:  
Chris@16: template <int RangeSize, bool Mutable>
Chris@16: class bit_range {
Chris@16: public:
Chris@16:     typedef typename mpl::if_c<Mutable,unsigned char,const unsigned char>::type byte_t;
Chris@16:     typedef std::ptrdiff_t difference_type;
Chris@16:     template <int RS, bool M> friend class bit_range;
Chris@16: private:
Chris@16:     byte_t* _current_byte;   // the starting byte of the bit range
Chris@16:     int     _bit_offset;     // offset from the beginning of the current byte. 0<=_bit_offset<=7
Chris@16: 
Chris@16: public:
Chris@16:     bit_range() : _current_byte(NULL), _bit_offset(0) {}
Chris@16:     bit_range(byte_t* current_byte, int bit_offset) : _current_byte(current_byte), _bit_offset(bit_offset) { assert(bit_offset>=0 && bit_offset<8); } 
Chris@16: 
Chris@16:     bit_range(const bit_range& br) : _current_byte(br._current_byte), _bit_offset(br._bit_offset) {}
Chris@16:     template <bool M> bit_range(const bit_range<RangeSize,M>& br) : _current_byte(br._current_byte), _bit_offset(br._bit_offset) {}
Chris@16: 
Chris@16:     bit_range& operator=(const bit_range& br) { _current_byte = br._current_byte; _bit_offset=br._bit_offset; return *this; }
Chris@16:     bool operator==(const bit_range& br) const { return  _current_byte==br._current_byte && _bit_offset==br._bit_offset; }
Chris@16: 
Chris@16:     bit_range& operator++() {
Chris@16:         _current_byte += (_bit_offset+RangeSize) / 8;
Chris@16:         _bit_offset    = (_bit_offset+RangeSize) % 8;
Chris@16:         return *this;
Chris@16:     }
Chris@16:     bit_range& operator--() { bit_advance(-RangeSize); return *this; }
Chris@16: 
Chris@16:     void bit_advance(difference_type num_bits) {
Chris@16:         int new_offset = int(_bit_offset+num_bits);
Chris@16:         _current_byte += new_offset / 8;
Chris@16:         _bit_offset    = new_offset % 8;
Chris@16:         if (_bit_offset<0) {
Chris@16:             _bit_offset+=8;
Chris@16:             --_current_byte;
Chris@16:         }
Chris@16:     }
Chris@16:     difference_type bit_distance_to(const bit_range& b) const {
Chris@16:         return (b.current_byte() - current_byte())*8 + b.bit_offset()-bit_offset();
Chris@16:     }
Chris@16:     byte_t* current_byte() const { return _current_byte; }
Chris@16:     int     bit_offset()   const { return _bit_offset; }
Chris@16: };
Chris@16: 
Chris@16: 
Chris@16: /// \defgroup ColorBaseModelNonAlignedPixel bit_aligned_pixel_reference 
Chris@16: /// \ingroup ColorBaseModel
Chris@16: /// \brief A heterogeneous color base representing pixel that may not be byte aligned, i.e. it may correspond to a bit range that does not start/end at a byte boundary. Models ColorBaseConcept.
Chris@16: 
Chris@16: /**
Chris@16: \defgroup PixelModelNonAlignedPixel bit_aligned_pixel_reference 
Chris@16: \ingroup PixelModel
Chris@16: \brief A heterogeneous pixel reference used to represent non-byte-aligned pixels. Models PixelConcept
Chris@16: 
Chris@16: Example:
Chris@16: \code
Chris@16: unsigned char data=0;
Chris@16: 
Chris@16: // A mutable reference to a 6-bit BGR pixel in "123" format (1 bit for red, 2 bits for green, 3 bits for blue)
Chris@16: typedef const bit_aligned_pixel_reference<unsigned char, mpl::vector3_c<int,1,2,3>, rgb_layout_t, true>  rgb123_ref_t;
Chris@16: 
Chris@16: // create the pixel reference at bit offset 2
Chris@16: // (i.e. red = [2], green = [3,4], blue = [5,6,7] bits)
Chris@16: rgb123_ref_t ref(&data, 2); 
Chris@16: get_color(ref, red_t()) = 1;
Chris@16: assert(data == 0x04);
Chris@16: get_color(ref, green_t()) = 3;
Chris@16: assert(data == 0x1C);
Chris@16: get_color(ref, blue_t()) = 7;
Chris@16: assert(data == 0xFC);
Chris@16: \endcode
Chris@16: */
Chris@16: /// \ingroup ColorBaseModelNonAlignedPixel PixelModelNonAlignedPixel PixelBasedModel
Chris@16: /// \brief Heterogeneous pixel reference corresponding to non-byte-aligned bit range. Models ColorBaseConcept, PixelConcept, PixelBasedConcept
Chris@16: template <typename BitField,
Chris@16:           typename ChannelBitSizes,  // MPL integral vector defining the number of bits for each channel. For example, for 565RGB, vector_c<int,5,6,5>
Chris@16:           typename Layout, 
Chris@16:           bool IsMutable>
Chris@16: struct bit_aligned_pixel_reference {
Chris@16:     BOOST_STATIC_CONSTANT(int, bit_size = (mpl::accumulate<ChannelBitSizes, mpl::int_<0>, mpl::plus<mpl::_1, mpl::_2> >::type::value));
Chris@16:     typedef boost::gil::bit_range<bit_size,IsMutable>                                           bit_range_t;
Chris@16:     typedef BitField                                                                bitfield_t;  
Chris@16:     typedef typename mpl::if_c<IsMutable,unsigned char*,const unsigned char*>::type data_ptr_t;
Chris@16: 
Chris@16:     typedef Layout layout_t;
Chris@16: 
Chris@16:     typedef typename packed_pixel_type<bitfield_t,ChannelBitSizes,Layout>::type       value_type;
Chris@16:     typedef const bit_aligned_pixel_reference                                         reference;
Chris@16:     typedef const bit_aligned_pixel_reference<BitField,ChannelBitSizes,Layout,false>  const_reference;
Chris@16: 
Chris@16:     BOOST_STATIC_CONSTANT(bool, is_mutable = IsMutable);
Chris@16: 
Chris@16:     bit_aligned_pixel_reference(){}
Chris@16:     bit_aligned_pixel_reference(data_ptr_t data_ptr, int bit_offset)   : _bit_range(data_ptr, bit_offset) {}
Chris@16:     explicit bit_aligned_pixel_reference(const bit_range_t& bit_range) : _bit_range(bit_range) {}
Chris@16:     template <bool IsMutable2> bit_aligned_pixel_reference(const bit_aligned_pixel_reference<BitField,ChannelBitSizes,Layout,IsMutable2>& p) : _bit_range(p._bit_range) {}
Chris@16: 
Chris@16:     // Grayscale references can be constructed from the channel reference
Chris@16:     explicit bit_aligned_pixel_reference(const typename kth_element_type<bit_aligned_pixel_reference,0>::type channel0) : _bit_range(static_cast<data_ptr_t>(&channel0), channel0.first_bit()) {
Chris@16:         BOOST_STATIC_ASSERT((num_channels<bit_aligned_pixel_reference>::value==1));
Chris@16:     }
Chris@16: 
Chris@16:     // Construct from another compatible pixel type
Chris@16:     bit_aligned_pixel_reference(const bit_aligned_pixel_reference& p) : _bit_range(p._bit_range) {}
Chris@16:     template <typename BF, typename CR> bit_aligned_pixel_reference(packed_pixel<BF,CR,Layout>& p) : _bit_range(static_cast<data_ptr_t>(&gil::at_c<0>(p)), gil::at_c<0>(p).first_bit()) {
Chris@16:         check_compatible<packed_pixel<BF,CR,Layout> >();
Chris@16:     }
Chris@16: 
Chris@16:     const bit_aligned_pixel_reference& operator=(const bit_aligned_pixel_reference& p) const { static_copy(p,*this); return *this; }
Chris@16:     template <typename P> const bit_aligned_pixel_reference& operator=(const P& p) const { assign(p, mpl::bool_<is_pixel<P>::value>()); return *this; } 
Chris@16: 
Chris@16:     template <typename P> bool operator==(const P& p) const { return equal(p, mpl::bool_<is_pixel<P>::value>()); } 
Chris@16:     template <typename P> bool operator!=(const P& p) const { return !(*this==p); }
Chris@16: 
Chris@16:     const bit_aligned_pixel_reference* operator->()    const { return this; }
Chris@16: 
Chris@16:     const bit_range_t& bit_range() const { return _bit_range; }
Chris@16: private:
Chris@16:     mutable bit_range_t _bit_range;
Chris@16:     template <typename B, typename C, typename L, bool M> friend struct bit_aligned_pixel_reference;
Chris@16: 
Chris@16:     template <typename Pixel> static void check_compatible() { gil_function_requires<PixelsCompatibleConcept<Pixel,bit_aligned_pixel_reference> >(); }
Chris@16: 
Chris@16:     template <typename Pixel> void assign(const Pixel& p, mpl::true_) const { check_compatible<Pixel>(); static_copy(p,*this); } 
Chris@16:     template <typename Pixel> bool  equal(const Pixel& p, mpl::true_) const { check_compatible<Pixel>(); return static_equal(*this,p); } 
Chris@16: 
Chris@16: private:
Chris@16:     static void check_gray() {  BOOST_STATIC_ASSERT((is_same<typename Layout::color_space_t, gray_t>::value)); }
Chris@16:     template <typename Channel> void assign(const Channel& chan, mpl::false_) const { check_gray(); gil::at_c<0>(*this)=chan; }
Chris@16:     template <typename Channel> bool equal (const Channel& chan, mpl::false_) const { check_gray(); return gil::at_c<0>(*this)==chan; }
Chris@16: };
Chris@16: 
Chris@16: /////////////////////////////
Chris@16: //  ColorBasedConcept
Chris@16: /////////////////////////////
Chris@16: 
Chris@16: template <typename BitField, typename ChannelBitSizes, typename L, bool IsMutable, int K>  
Chris@16: struct kth_element_type<bit_aligned_pixel_reference<BitField,ChannelBitSizes,L,IsMutable>, K> {
Chris@16: public:
Chris@16:     typedef const packed_dynamic_channel_reference<BitField, mpl::at_c<ChannelBitSizes,K>::type::value, IsMutable> type;
Chris@16: };
Chris@16: 
Chris@16: template <typename B, typename C, typename L, bool M, int K>  
Chris@16: struct kth_element_reference_type<bit_aligned_pixel_reference<B,C,L,M>, K>
Chris@16:     : public kth_element_type<bit_aligned_pixel_reference<B,C,L,M>, K> {};
Chris@16: 
Chris@16: template <typename B, typename C, typename L, bool M, int K>  
Chris@16: struct kth_element_const_reference_type<bit_aligned_pixel_reference<B,C,L,M>, K>
Chris@16:     : public kth_element_type<bit_aligned_pixel_reference<B,C,L,M>, K> {};
Chris@16: 
Chris@16: 
Chris@16: namespace detail {
Chris@16:     // returns sum of IntegralVector[0] ... IntegralVector[K-1]
Chris@16:     template <typename IntegralVector, int K> 
Chris@16:     struct sum_k : public mpl::plus<sum_k<IntegralVector,K-1>, typename mpl::at_c<IntegralVector,K-1>::type > {};
Chris@16: 
Chris@16:     template <typename IntegralVector> struct sum_k<IntegralVector,0> : public mpl::int_<0> {};
Chris@16: }
Chris@16: 
Chris@16: // at_c required by MutableColorBaseConcept
Chris@16: template <int K, typename BitField, typename ChannelBitSizes, typename L, bool Mutable> inline
Chris@16: typename kth_element_reference_type<bit_aligned_pixel_reference<BitField,ChannelBitSizes,L,Mutable>,K>::type
Chris@16: at_c(const bit_aligned_pixel_reference<BitField,ChannelBitSizes,L,Mutable>& p) { 
Chris@16:     typedef bit_aligned_pixel_reference<BitField,ChannelBitSizes,L,Mutable> pixel_t;
Chris@16:     typedef typename kth_element_reference_type<pixel_t,K>::type channel_t;
Chris@16:     typedef typename pixel_t::bit_range_t bit_range_t;
Chris@16: 
Chris@16:     bit_range_t bit_range(p.bit_range());
Chris@16:     bit_range.bit_advance(detail::sum_k<ChannelBitSizes,K>::value);
Chris@16: 
Chris@16:     return channel_t(bit_range.current_byte(), bit_range.bit_offset()); 
Chris@16: }
Chris@16: 
Chris@16: /////////////////////////////
Chris@16: //  PixelConcept
Chris@16: /////////////////////////////
Chris@16: 
Chris@16: /// Metafunction predicate that flags bit_aligned_pixel_reference as a model of PixelConcept. Required by PixelConcept
Chris@16: template <typename B, typename C, typename L, bool M>  
Chris@16: struct is_pixel<bit_aligned_pixel_reference<B,C,L,M> > : public mpl::true_{};
Chris@16: 
Chris@16: /////////////////////////////
Chris@16: //  PixelBasedConcept
Chris@16: /////////////////////////////
Chris@16: 
Chris@16: template <typename B, typename C, typename L, bool M>
Chris@16: struct color_space_type<bit_aligned_pixel_reference<B,C,L,M> > {
Chris@16:     typedef typename L::color_space_t type;
Chris@16: }; 
Chris@16: 
Chris@16: template <typename B, typename C, typename L, bool M>
Chris@16: struct channel_mapping_type<bit_aligned_pixel_reference<B,C,L,M> > {
Chris@16:     typedef typename L::channel_mapping_t type;
Chris@16: }; 
Chris@16: 
Chris@16: template <typename B, typename C, typename L, bool M>
Chris@16: struct is_planar<bit_aligned_pixel_reference<B,C,L,M> > : mpl::false_ {}; 
Chris@16: 
Chris@16: /////////////////////////////
Chris@16: //  pixel_reference_type
Chris@16: /////////////////////////////
Chris@16: 
Chris@16: namespace detail {
Chris@16:     // returns a vector containing K copies of the type T
Chris@16:     template <unsigned K, typename T> struct k_copies;
Chris@16:     template <typename T> struct k_copies<0,T> {
Chris@16:         typedef mpl::vector0<> type;
Chris@16:     };
Chris@16:     template <unsigned K, typename T> struct k_copies : public mpl::push_back<typename k_copies<K-1,T>::type, T> {};
Chris@16: }
Chris@16: 
Chris@16: // Constructs a homogeneous bit_aligned_pixel_reference given a channel reference
Chris@16: template <typename BitField, int NumBits, typename Layout> 
Chris@16: struct pixel_reference_type<const packed_dynamic_channel_reference<BitField,NumBits,false>, Layout, false, false> {
Chris@16: private:
Chris@16:     typedef typename mpl::size<typename Layout::color_space_t>::type size_t;
Chris@16:     typedef typename detail::k_copies<size_t::value,mpl::integral_c<unsigned,NumBits> >::type channel_bit_sizes_t;
Chris@16: public:
Chris@16:     typedef bit_aligned_pixel_reference<BitField, channel_bit_sizes_t, Layout, false> type;
Chris@16: };
Chris@16: 
Chris@16: // Same but for the mutable case. We cannot combine the mutable and read-only cases because this triggers ambiguity
Chris@16: template <typename BitField, int NumBits, typename Layout> 
Chris@16: struct pixel_reference_type<const packed_dynamic_channel_reference<BitField,NumBits,true>, Layout, false, true> {
Chris@16: private:
Chris@16:     typedef typename mpl::size<typename Layout::color_space_t>::type size_t;
Chris@16:     typedef typename detail::k_copies<size_t::value,mpl::integral_c<unsigned,NumBits> >::type channel_bit_sizes_t;
Chris@16: public:
Chris@16:     typedef bit_aligned_pixel_reference<BitField, channel_bit_sizes_t, Layout, true> type;
Chris@16: };
Chris@16: 
Chris@16: } }  // namespace boost::gil
Chris@16: 
Chris@16: namespace std {
Chris@16: // We are forced to define swap inside std namespace because on some platforms (Visual Studio 8) STL calls swap qualified.
Chris@16: // swap with 'left bias': 
Chris@16: // - swap between proxy and anything
Chris@16: // - swap between value type and proxy
Chris@16: // - swap between proxy and proxy
Chris@16: // Having three overloads allows us to swap between different (but compatible) models of PixelConcept
Chris@16: 
Chris@16: template <typename B, typename C, typename L, typename R> inline
Chris@16: void swap(const boost::gil::bit_aligned_pixel_reference<B,C,L,true> x, R& y) { 
Chris@16:     boost::gil::swap_proxy<typename boost::gil::bit_aligned_pixel_reference<B,C,L,true>::value_type>(x,y); 
Chris@16: }
Chris@16: 
Chris@16: 
Chris@16: template <typename B, typename C, typename L> inline
Chris@16: void swap(typename boost::gil::bit_aligned_pixel_reference<B,C,L,true>::value_type& x, const boost::gil::bit_aligned_pixel_reference<B,C,L,true> y) { 
Chris@16:     boost::gil::swap_proxy<typename boost::gil::bit_aligned_pixel_reference<B,C,L,true>::value_type>(x,y); 
Chris@16: }
Chris@16: 
Chris@16: 
Chris@16: template <typename B, typename C, typename L> inline
Chris@16: void swap(const boost::gil::bit_aligned_pixel_reference<B,C,L,true> x, const boost::gil::bit_aligned_pixel_reference<B,C,L,true> y) { 
Chris@16:     boost::gil::swap_proxy<typename boost::gil::bit_aligned_pixel_reference<B,C,L,true>::value_type>(x,y); 
Chris@16: }
Chris@16: }   // namespace std
Chris@16: #endif