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