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://stlab.adobe.com/gil for most recent version including documentation. |
9 | */ |
10 | |
11 | /*************************************************************************************************/ |
12 | |
13 | #ifndef GIL_BIT_ALIGNED_PIXEL_REFERENCE_HPP |
14 | #define GIL_BIT_ALIGNED_PIXEL_REFERENCE_HPP |
15 | |
16 | //////////////////////////////////////////////////////////////////////////////////////// |
17 | /// \file |
18 | /// \brief A model of a heterogeneous pixel that is not byte aligned. Examples are bitmap (1-bit pixels) or 6-bit RGB (222) |
19 | /// \author Lubomir Bourdev and Hailin Jin \n |
20 | /// Adobe Systems Incorporated |
21 | /// \date 2005-2007 \n Last updated on September 28, 2006 |
22 | /// |
23 | //////////////////////////////////////////////////////////////////////////////////////// |
24 | |
25 | #include <functional> |
26 | #include <boost/mpl/accumulate.hpp> |
27 | #include <boost/mpl/at.hpp> |
28 | #include <boost/mpl/bool.hpp> |
29 | #include <boost/mpl/if.hpp> |
30 | #include <boost/mpl/plus.hpp> |
31 | #include <boost/mpl/push_back.hpp> |
32 | #include <boost/mpl/vector.hpp> |
33 | #include "gil_config.hpp" |
34 | #include "pixel.hpp" |
35 | #include "channel.hpp" |
36 | |
37 | namespace boost { namespace gil { |
38 | |
39 | ///////////////////////////// |
40 | // bit_range |
41 | // |
42 | // 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. |
43 | ///////////////////////////// |
44 | |
45 | template <int RangeSize, bool Mutable> |
46 | class bit_range { |
47 | public: |
48 | typedef typename mpl::if_c<Mutable,unsigned char,const unsigned char>::type byte_t; |
49 | typedef std::ptrdiff_t difference_type; |
50 | template <int RS, bool M> friend class bit_range; |
51 | private: |
52 | byte_t* _current_byte; // the starting byte of the bit range |
53 | int _bit_offset; // offset from the beginning of the current byte. 0<=_bit_offset<=7 |
54 | |
55 | public: |
56 | bit_range() : _current_byte(NULL), _bit_offset(0) {} |
57 | bit_range(byte_t* current_byte, int bit_offset) : _current_byte(current_byte), _bit_offset(bit_offset) { assert(bit_offset>=0 && bit_offset<8); } |
58 | |
59 | bit_range(const bit_range& br) : _current_byte(br._current_byte), _bit_offset(br._bit_offset) {} |
60 | template <bool M> bit_range(const bit_range<RangeSize,M>& br) : _current_byte(br._current_byte), _bit_offset(br._bit_offset) {} |
61 | |
62 | bit_range& operator=(const bit_range& br) { _current_byte = br._current_byte; _bit_offset=br._bit_offset; return *this; } |
63 | bool operator==(const bit_range& br) const { return _current_byte==br._current_byte && _bit_offset==br._bit_offset; } |
64 | |
65 | bit_range& operator++() { |
66 | _current_byte += (_bit_offset+RangeSize) / 8; |
67 | _bit_offset = (_bit_offset+RangeSize) % 8; |
68 | return *this; |
69 | } |
70 | bit_range& operator--() { bit_advance(num_bits: -RangeSize); return *this; } |
71 | |
72 | void bit_advance(difference_type num_bits) { |
73 | int new_offset = int(_bit_offset+num_bits); |
74 | _current_byte += new_offset / 8; |
75 | _bit_offset = new_offset % 8; |
76 | if (_bit_offset<0) { |
77 | _bit_offset+=8; |
78 | --_current_byte; |
79 | } |
80 | } |
81 | difference_type bit_distance_to(const bit_range& b) const { |
82 | return (b.current_byte() - current_byte())*8 + b.bit_offset()-bit_offset(); |
83 | } |
84 | byte_t* current_byte() const { return _current_byte; } |
85 | int bit_offset() const { return _bit_offset; } |
86 | }; |
87 | |
88 | |
89 | /// \defgroup ColorBaseModelNonAlignedPixel bit_aligned_pixel_reference |
90 | /// \ingroup ColorBaseModel |
91 | /// \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. |
92 | |
93 | /** |
94 | \defgroup PixelModelNonAlignedPixel bit_aligned_pixel_reference |
95 | \ingroup PixelModel |
96 | \brief A heterogeneous pixel reference used to represent non-byte-aligned pixels. Models PixelConcept |
97 | |
98 | Example: |
99 | \code |
100 | unsigned char data=0; |
101 | |
102 | // A mutable reference to a 6-bit BGR pixel in "123" format (1 bit for red, 2 bits for green, 3 bits for blue) |
103 | typedef const bit_aligned_pixel_reference<unsigned char, mpl::vector3_c<int,1,2,3>, rgb_layout_t, true> rgb123_ref_t; |
104 | |
105 | // create the pixel reference at bit offset 2 |
106 | // (i.e. red = [2], green = [3,4], blue = [5,6,7] bits) |
107 | rgb123_ref_t ref(&data, 2); |
108 | get_color(ref, red_t()) = 1; |
109 | assert(data == 0x04); |
110 | get_color(ref, green_t()) = 3; |
111 | assert(data == 0x1C); |
112 | get_color(ref, blue_t()) = 7; |
113 | assert(data == 0xFC); |
114 | \endcode |
115 | */ |
116 | /// \ingroup ColorBaseModelNonAlignedPixel PixelModelNonAlignedPixel PixelBasedModel |
117 | /// \brief Heterogeneous pixel reference corresponding to non-byte-aligned bit range. Models ColorBaseConcept, PixelConcept, PixelBasedConcept |
118 | template <typename BitField, |
119 | typename ChannelBitSizes, // MPL integral vector defining the number of bits for each channel. For example, for 565RGB, vector_c<int,5,6,5> |
120 | typename Layout, |
121 | bool IsMutable> |
122 | struct bit_aligned_pixel_reference { |
123 | BOOST_STATIC_CONSTANT(int, bit_size = (mpl::accumulate<ChannelBitSizes, mpl::int_<0>, mpl::plus<mpl::_1, mpl::_2> >::type::value)); |
124 | typedef boost::gil::bit_range<bit_size,IsMutable> bit_range_t; |
125 | typedef BitField bitfield_t; |
126 | typedef typename mpl::if_c<IsMutable,unsigned char*,const unsigned char*>::type data_ptr_t; |
127 | |
128 | typedef Layout layout_t; |
129 | |
130 | typedef typename packed_pixel_type<bitfield_t,ChannelBitSizes,Layout>::type value_type; |
131 | typedef const bit_aligned_pixel_reference reference; |
132 | typedef const bit_aligned_pixel_reference<BitField,ChannelBitSizes,Layout,false> const_reference; |
133 | |
134 | BOOST_STATIC_CONSTANT(bool, is_mutable = IsMutable); |
135 | |
136 | bit_aligned_pixel_reference(){} |
137 | bit_aligned_pixel_reference(data_ptr_t data_ptr, int bit_offset) : _bit_range(data_ptr, bit_offset) {} |
138 | explicit bit_aligned_pixel_reference(const bit_range_t& bit_range) : _bit_range(bit_range) {} |
139 | template <bool IsMutable2> bit_aligned_pixel_reference(const bit_aligned_pixel_reference<BitField,ChannelBitSizes,Layout,IsMutable2>& p) : _bit_range(p._bit_range) {} |
140 | |
141 | // Grayscale references can be constructed from the channel reference |
142 | 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()) { |
143 | BOOST_STATIC_ASSERT((num_channels<bit_aligned_pixel_reference>::value==1)); |
144 | } |
145 | |
146 | // Construct from another compatible pixel type |
147 | bit_aligned_pixel_reference(const bit_aligned_pixel_reference& p) : _bit_range(p._bit_range) {} |
148 | 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()) { |
149 | check_compatible<packed_pixel<BF,CR,Layout> >(); |
150 | } |
151 | |
152 | const bit_aligned_pixel_reference& operator=(const bit_aligned_pixel_reference& p) const { static_copy(p,*this); return *this; } |
153 | template <typename P> const bit_aligned_pixel_reference& operator=(const P& p) const { assign(p, mpl::bool_<is_pixel<P>::value>()); return *this; } |
154 | |
155 | template <typename P> bool operator==(const P& p) const { return equal(p, mpl::bool_<is_pixel<P>::value>()); } |
156 | template <typename P> bool operator!=(const P& p) const { return !(*this==p); } |
157 | |
158 | const bit_aligned_pixel_reference* operator->() const { return this; } |
159 | |
160 | const bit_range_t& bit_range() const { return _bit_range; } |
161 | private: |
162 | mutable bit_range_t _bit_range; |
163 | template <typename B, typename C, typename L, bool M> friend struct bit_aligned_pixel_reference; |
164 | |
165 | template <typename Pixel> static void check_compatible() { gil_function_requires<PixelsCompatibleConcept<Pixel,bit_aligned_pixel_reference> >(); } |
166 | |
167 | template <typename Pixel> void assign(const Pixel& p, mpl::true_) const { check_compatible<Pixel>(); static_copy(p,*this); } |
168 | template <typename Pixel> bool equal(const Pixel& p, mpl::true_) const { check_compatible<Pixel>(); return static_equal(*this,p); } |
169 | |
170 | private: |
171 | static void check_gray() { BOOST_STATIC_ASSERT((is_same<typename Layout::color_space_t, gray_t>::value)); } |
172 | template <typename Channel> void assign(const Channel& chan, mpl::false_) const { check_gray(); gil::at_c<0>(*this)=chan; } |
173 | template <typename Channel> bool equal (const Channel& chan, mpl::false_) const { check_gray(); return gil::at_c<0>(*this)==chan; } |
174 | }; |
175 | |
176 | ///////////////////////////// |
177 | // ColorBasedConcept |
178 | ///////////////////////////// |
179 | |
180 | template <typename BitField, typename ChannelBitSizes, typename L, bool IsMutable, int K> |
181 | struct kth_element_type<bit_aligned_pixel_reference<BitField,ChannelBitSizes,L,IsMutable>, K> { |
182 | public: |
183 | typedef const packed_dynamic_channel_reference<BitField, mpl::at_c<ChannelBitSizes,K>::type::value, IsMutable> type; |
184 | }; |
185 | |
186 | template <typename B, typename C, typename L, bool M, int K> |
187 | struct kth_element_reference_type<bit_aligned_pixel_reference<B,C,L,M>, K> |
188 | : public kth_element_type<bit_aligned_pixel_reference<B,C,L,M>, K> {}; |
189 | |
190 | template <typename B, typename C, typename L, bool M, int K> |
191 | struct kth_element_const_reference_type<bit_aligned_pixel_reference<B,C,L,M>, K> |
192 | : public kth_element_type<bit_aligned_pixel_reference<B,C,L,M>, K> {}; |
193 | |
194 | |
195 | namespace detail { |
196 | // returns sum of IntegralVector[0] ... IntegralVector[K-1] |
197 | template <typename IntegralVector, int K> |
198 | struct sum_k : public mpl::plus<sum_k<IntegralVector,K-1>, typename mpl::at_c<IntegralVector,K-1>::type > {}; |
199 | |
200 | template <typename IntegralVector> struct sum_k<IntegralVector,0> : public mpl::int_<0> {}; |
201 | } |
202 | |
203 | // at_c required by MutableColorBaseConcept |
204 | template <int K, typename BitField, typename ChannelBitSizes, typename L, bool Mutable> inline |
205 | typename kth_element_reference_type<bit_aligned_pixel_reference<BitField,ChannelBitSizes,L,Mutable>,K>::type |
206 | at_c(const bit_aligned_pixel_reference<BitField,ChannelBitSizes,L,Mutable>& p) { |
207 | typedef bit_aligned_pixel_reference<BitField,ChannelBitSizes,L,Mutable> pixel_t; |
208 | typedef typename kth_element_reference_type<pixel_t,K>::type channel_t; |
209 | typedef typename pixel_t::bit_range_t bit_range_t; |
210 | |
211 | bit_range_t bit_range(p.bit_range()); |
212 | bit_range.bit_advance(detail::sum_k<ChannelBitSizes,K>::value); |
213 | |
214 | return channel_t(bit_range.current_byte(), bit_range.bit_offset()); |
215 | } |
216 | |
217 | ///////////////////////////// |
218 | // PixelConcept |
219 | ///////////////////////////// |
220 | |
221 | /// Metafunction predicate that flags bit_aligned_pixel_reference as a model of PixelConcept. Required by PixelConcept |
222 | template <typename B, typename C, typename L, bool M> |
223 | struct is_pixel<bit_aligned_pixel_reference<B,C,L,M> > : public mpl::true_{}; |
224 | |
225 | ///////////////////////////// |
226 | // PixelBasedConcept |
227 | ///////////////////////////// |
228 | |
229 | template <typename B, typename C, typename L, bool M> |
230 | struct color_space_type<bit_aligned_pixel_reference<B,C,L,M> > { |
231 | typedef typename L::color_space_t type; |
232 | }; |
233 | |
234 | template <typename B, typename C, typename L, bool M> |
235 | struct channel_mapping_type<bit_aligned_pixel_reference<B,C,L,M> > { |
236 | typedef typename L::channel_mapping_t type; |
237 | }; |
238 | |
239 | template <typename B, typename C, typename L, bool M> |
240 | struct is_planar<bit_aligned_pixel_reference<B,C,L,M> > : mpl::false_ {}; |
241 | |
242 | ///////////////////////////// |
243 | // pixel_reference_type |
244 | ///////////////////////////// |
245 | |
246 | namespace detail { |
247 | // returns a vector containing K copies of the type T |
248 | template <unsigned K, typename T> struct k_copies; |
249 | template <typename T> struct k_copies<0,T> { |
250 | typedef mpl::vector0<> type; |
251 | }; |
252 | template <unsigned K, typename T> struct k_copies : public mpl::push_back<typename k_copies<K-1,T>::type, T> {}; |
253 | } |
254 | |
255 | // Constructs a homogeneous bit_aligned_pixel_reference given a channel reference |
256 | template <typename BitField, int NumBits, typename Layout> |
257 | struct pixel_reference_type<const packed_dynamic_channel_reference<BitField,NumBits,false>, Layout, false, false> { |
258 | private: |
259 | typedef typename mpl::size<typename Layout::color_space_t>::type size_t; |
260 | typedef typename detail::k_copies<size_t::value,mpl::integral_c<unsigned,NumBits> >::type channel_bit_sizes_t; |
261 | public: |
262 | typedef bit_aligned_pixel_reference<BitField, channel_bit_sizes_t, Layout, false> type; |
263 | }; |
264 | |
265 | // Same but for the mutable case. We cannot combine the mutable and read-only cases because this triggers ambiguity |
266 | template <typename BitField, int NumBits, typename Layout> |
267 | struct pixel_reference_type<const packed_dynamic_channel_reference<BitField,NumBits,true>, Layout, false, true> { |
268 | private: |
269 | typedef typename mpl::size<typename Layout::color_space_t>::type size_t; |
270 | typedef typename detail::k_copies<size_t::value,mpl::integral_c<unsigned,NumBits> >::type channel_bit_sizes_t; |
271 | public: |
272 | typedef bit_aligned_pixel_reference<BitField, channel_bit_sizes_t, Layout, true> type; |
273 | }; |
274 | |
275 | } } // namespace boost::gil |
276 | |
277 | namespace std { |
278 | // We are forced to define swap inside std namespace because on some platforms (Visual Studio 8) STL calls swap qualified. |
279 | // swap with 'left bias': |
280 | // - swap between proxy and anything |
281 | // - swap between value type and proxy |
282 | // - swap between proxy and proxy |
283 | // Having three overloads allows us to swap between different (but compatible) models of PixelConcept |
284 | |
285 | template <typename B, typename C, typename L, typename R> inline |
286 | void swap(const boost::gil::bit_aligned_pixel_reference<B,C,L,true> x, R& y) { |
287 | boost::gil::swap_proxy<typename boost::gil::bit_aligned_pixel_reference<B,C,L,true>::value_type>(x,y); |
288 | } |
289 | |
290 | |
291 | template <typename B, typename C, typename L> inline |
292 | 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) { |
293 | boost::gil::swap_proxy<typename boost::gil::bit_aligned_pixel_reference<B,C,L,true>::value_type>(x,y); |
294 | } |
295 | |
296 | |
297 | template <typename B, typename C, typename L> inline |
298 | 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) { |
299 | boost::gil::swap_proxy<typename boost::gil::bit_aligned_pixel_reference<B,C,L,true>::value_type>(x,y); |
300 | } |
301 | } // namespace std |
302 | #endif |
303 | |