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_METAFUNCTIONS_HPP
14 #define GIL_METAFUNCTIONS_HPP
15 
16 ////////////////////////////////////////////////////////////////////////////////////////
17 /// \file
18 /// \brief metafunctions that construct types or return type properties
19 /// \author Lubomir Bourdev and Hailin Jin \n
20 ///         Adobe Systems Incorporated
21 ///
22 /// \date 2005-2007 \n Last updated on February 6, 2007
23 ///
24 ////////////////////////////////////////////////////////////////////////////////////////
25 
26 #include <iterator>
27 #include <boost/mpl/accumulate.hpp>
28 #include <boost/mpl/back.hpp>
29 #include <boost/mpl/bool.hpp>
30 #include <boost/mpl/if.hpp>
31 #include <boost/mpl/pop_back.hpp>
32 #include <boost/mpl/push_back.hpp>
33 #include <boost/mpl/transform.hpp>
34 #include <boost/mpl/vector.hpp>
35 #include <boost/type_traits.hpp>
36 #include "gil_config.hpp"
37 #include "gil_concept.hpp"
38 #include "channel.hpp"
39 
40 namespace boost { namespace gil {
41 
42 // forward declarations
43 template <typename T, typename L> struct pixel;
44 template <typename BitField,typename ChannelRefVec,typename Layout> struct packed_pixel;
45 template <typename T, typename C> struct planar_pixel_reference;
46 template <typename IC, typename C> struct planar_pixel_iterator;
47 template <typename I> class memory_based_step_iterator;
48 template <typename I> class memory_based_2d_locator;
49 template <typename L> class image_view;
50 template <typename Pixel, bool IsPlanar, typename Alloc> class image;
51 template <typename T> struct channel_type;
52 template <typename T> struct color_space_type;
53 template <typename T> struct channel_mapping_type;
54 template <typename It> struct is_iterator_adaptor;
55 template <typename It> struct iterator_adaptor_get_base;
56 template <typename BitField, typename ChannelBitSizes, typename Layout, bool IsMutable> struct bit_aligned_pixel_reference;
57 
58 //////////////////////////////////////////////////
59 ///
60 ///  TYPE ANALYSIS METAFUNCTIONS
61 ///  Predicate metafunctions determining properties of GIL types
62 ///
63 //////////////////////////////////////////////////
64 
65 
66 /// \defgroup GILIsBasic xxx_is_basic
67 /// \ingroup TypeAnalysis
68 /// \brief Determines if GIL constructs are basic.
69 ///    Basic constructs are the ones that can be generated with the type
70 ///    factory methods pixel_reference_type, iterator_type, locator_type, view_type and image_type
71 ///    They can be mutable/immutable, planar/interleaved, step/nonstep. They must use GIL-provided models.
72 
73 /// \brief Determines if a given pixel reference is basic
74 ///    Basic references must use gil::pixel& (if interleaved), gil::planar_pixel_reference (if planar). They must use the standard constness rules.
75 /// \ingroup GILIsBasic
76 template <typename PixelRef>        struct pixel_reference_is_basic                     : public mpl::false_ {};
77 template <typename T,  typename L>  struct pixel_reference_is_basic<      pixel<T,L>&>  : public mpl::true_ {};
78 template <typename T,  typename L>  struct pixel_reference_is_basic<const pixel<T,L>&>  : public mpl::true_ {};
79 template <typename TR, typename Cs> struct pixel_reference_is_basic<planar_pixel_reference<TR,Cs> > : public mpl::true_ {};
80 template <typename TR, typename Cs> struct pixel_reference_is_basic<const planar_pixel_reference<TR,Cs> > : public mpl::true_ {};
81 
82 
83 /// \brief Determines if a given pixel iterator is basic
84 ///    Basic iterators must use gil::pixel (if interleaved), gil::planar_pixel_iterator (if planar) and gil::memory_based_step_iterator (if step). They must use the standard constness rules.
85 /// \ingroup GILIsBasic
86 template <typename Iterator>
87 struct iterator_is_basic : public mpl::false_ {};
88 template <typename T, typename L>  // mutable   interleaved
89 struct iterator_is_basic<      pixel<T,L>*      > : public mpl::true_ {};
90 template <typename T, typename L>  // immutable interleaved
91 struct iterator_is_basic<const pixel<T,L>*      > : public mpl::true_ {};
92 template <typename T, typename Cs>  // mutable   planar
93 struct iterator_is_basic<planar_pixel_iterator<      T*,Cs> > : public mpl::true_ {};
94 template <typename T, typename Cs>    // immutable planar
95 struct iterator_is_basic<planar_pixel_iterator<const T*,Cs> > : public mpl::true_ {};
96 template <typename T, typename L>  // mutable   interleaved step
97 struct iterator_is_basic<memory_based_step_iterator<      pixel<T,L>*> > : public mpl::true_ {};
98 template <typename T, typename L>  // immutable interleaved step
99 struct iterator_is_basic<memory_based_step_iterator<const pixel<T,L>*> > : public mpl::true_ {};
100 template <typename T, typename Cs>  // mutable   planar step
101 struct iterator_is_basic<memory_based_step_iterator<planar_pixel_iterator<      T*,Cs> > > : public mpl::true_ {};
102 template <typename T, typename Cs>    // immutable planar step
103 struct iterator_is_basic<memory_based_step_iterator<planar_pixel_iterator<const T*,Cs> > > : public mpl::true_ {};
104 
105 
106 /// \ingroup GILIsBasic
107 /// \brief Determines if a given locator is basic. A basic locator is memory-based and has basic x_iterator and y_iterator
108 template <typename Loc> struct locator_is_basic : public mpl::false_ {};
109 template <typename Iterator> struct locator_is_basic<memory_based_2d_locator<memory_based_step_iterator<Iterator> > > : public iterator_is_basic<Iterator> {};
110 
111 /// \ingroup GILIsBasic
112 /// \brief Basic views must be over basic locators
113 template <typename View> struct view_is_basic : public mpl::false_ {};
114 template <typename Loc> struct view_is_basic<image_view<Loc> > : public locator_is_basic<Loc> {};
115 
116 /// \ingroup GILIsBasic
117 /// \brief Basic images must use basic views and std::allocator of char
118 template <typename Img> struct image_is_basic : public mpl::false_ {};
119 template <typename Pixel, bool IsPlanar, typename Alloc> struct image_is_basic<image<Pixel,IsPlanar,Alloc> > : public mpl::true_ {};
120 
121 
122 /// \defgroup GILIsStep xxx_is_step
123 /// \ingroup TypeAnalysis
124 /// \brief Determines if the given iterator/locator/view has a step that could be set dynamically
125 
126 template <typename I> struct iterator_is_step;
127 namespace detail {
128     template <typename It, bool IsBase, bool EqualsStepType> struct iterator_is_step_impl;
129     // iterator that has the same type as its dynamic_x_step_type must be a step iterator
130     template <typename It, bool IsBase> struct iterator_is_step_impl<It,IsBase,true> : public mpl::true_{};
131 
132     // base iterator can never be a step iterator
133     template <typename It> struct iterator_is_step_impl<It,true,false> : public mpl::false_{};
134 
135     // for an iterator adaptor, see if its base is step
136     template <typename It> struct iterator_is_step_impl<It,false,false>
137         : public iterator_is_step<typename iterator_adaptor_get_base<It>::type>{};
138 }
139 
140 /// \ingroup GILIsStep
141 /// \brief Determines if the given iterator has a step that could be set dynamically
142 template <typename I> struct iterator_is_step
143     : public detail::iterator_is_step_impl<I,
144         !is_iterator_adaptor<I>::type::value,
145         is_same<I,typename dynamic_x_step_type<I>::type>::value >{};
146 
147 /// \ingroup GILIsStep
148 /// \brief Determines if the given locator has a horizontal step that could be set dynamically
149 template <typename L> struct locator_is_step_in_x : public iterator_is_step<typename L::x_iterator> {};
150 
151 /// \ingroup GILIsStep
152 /// \brief Determines if the given locator has a vertical step that could be set dynamically
153 template <typename L> struct locator_is_step_in_y : public iterator_is_step<typename L::y_iterator> {};
154 
155 /// \ingroup GILIsStep
156 /// \brief Determines if the given view has a horizontal step that could be set dynamically
157 template <typename V> struct view_is_step_in_x : public locator_is_step_in_x<typename V::xy_locator> {};
158 
159 /// \ingroup GILIsStep
160 /// \brief Determines if the given view has a vertical step that could be set dynamically
161 template <typename V> struct view_is_step_in_y : public locator_is_step_in_y<typename V::xy_locator> {};
162 
163 /// \brief Determines whether the given pixel reference is a proxy class or a native C++ reference
164 /// \ingroup TypeAnalysis
165 template <typename PixelReference>
166 struct pixel_reference_is_proxy
167     : public mpl::not_<is_same<typename remove_const_and_reference<PixelReference>::type,
168                                typename remove_const_and_reference<PixelReference>::type::value_type> > {};
169 
170 /// \brief Given a model of a pixel, determines whether the model represents a pixel reference (as opposed to pixel value)
171 /// \ingroup TypeAnalysis
172 template <typename Pixel>
173 struct pixel_is_reference : public mpl::or_<is_reference<Pixel>, pixel_reference_is_proxy<Pixel> > {};
174 
175 /// \defgroup GILIsMutable xxx_is_mutable
176 /// \ingroup TypeAnalysis
177 /// \brief Determines if the given pixel reference/iterator/locator/view is mutable (i.e. its pixels can be changed)
178 
179 /// \ingroup GILIsMutable
180 /// \brief Determines if the given pixel reference is mutable (i.e. its channels can be changed)
181 ///
182 /// Note that built-in C++ references obey the const qualifier but reference proxy classes do not.
183 template <typename R> struct pixel_reference_is_mutable : public mpl::bool_<remove_reference<R>::type::is_mutable> {};
184 template <typename R> struct pixel_reference_is_mutable<const R&>
185     : public mpl::and_<pixel_reference_is_proxy<R>, pixel_reference_is_mutable<R> > {};
186 
187 /// \ingroup GILIsMutable
188 /// \brief Determines if the given locator is mutable (i.e. its pixels can be changed)
189 template <typename L> struct locator_is_mutable : public iterator_is_mutable<typename L::x_iterator> {};
190 /// \ingroup GILIsMutable
191 /// \brief Determines if the given view is mutable (i.e. its pixels can be changed)
192 template <typename V> struct view_is_mutable : public iterator_is_mutable<typename V::x_iterator> {};
193 
194 
195 //////////////////////////////////////////////////
196 ///
197 ///  TYPE FACTORY METAFUNCTIONS
198 ///  Metafunctions returning GIL types from other GIL types
199 ///
200 //////////////////////////////////////////////////
201 
202 /// \defgroup TypeFactoryFromElements xxx_type
203 /// \ingroup TypeFactory
204 /// \brief Returns the type of a homogeneous GIL construct given its elements (channel, layout, whether it is planar, step, mutable, etc.)
205 
206 /// \defgroup TypeFactoryFromPixel xxx_type_from_pixel
207 /// \ingroup TypeFactory
208 /// \brief Returns the type of a GIL construct given its pixel type, whether it is planar, step, mutable, etc.
209 
210 /// \defgroup TypeFactoryDerived derived_xxx_type
211 /// \ingroup TypeFactory
212 /// \brief Returns the type of a homogeneous GIL construct given a related construct by changing some of its properties
213 
214 /// \ingroup TypeFactoryFromElements
215 /// \brief Returns the type of a homogeneous pixel reference given the channel type, layout, whether it operates on planar data and whether it is mutable
216 template <typename T, typename L, bool IsPlanar=false, bool IsMutable=true> struct pixel_reference_type{};
217 template <typename T, typename L> struct pixel_reference_type<T,L,false,true > { typedef pixel<T,L>& type; };
218 template <typename T, typename L> struct pixel_reference_type<T,L,false,false> { typedef const pixel<T,L>& type; };
219 template <typename T, typename L> struct pixel_reference_type<T,L,true,true> { typedef const planar_pixel_reference<typename channel_traits<T>::reference,typename color_space_type<L>::type> type; };       // TODO: Assert M=identity
220 template <typename T, typename L> struct pixel_reference_type<T,L,true,false> { typedef const planar_pixel_reference<typename channel_traits<T>::const_reference,typename color_space_type<L>::type> type; };// TODO: Assert M=identity
221 
222 /// \ingroup TypeFactoryFromPixel
223 /// \brief Returns the type of a pixel iterator given the pixel type, whether it operates on planar data, whether it is a step iterator, and whether it is mutable
224 template <typename Pixel, bool IsPlanar=false, bool IsStep=false, bool IsMutable=true> struct iterator_type_from_pixel{};
225 template <typename Pixel> struct iterator_type_from_pixel<Pixel,false,false,true > { typedef Pixel* type; };
226 template <typename Pixel> struct iterator_type_from_pixel<Pixel,false,false,false> { typedef const Pixel* type; };
227 template <typename Pixel> struct iterator_type_from_pixel<Pixel,true,false,true> {
228     typedef planar_pixel_iterator<typename channel_traits<typename channel_type<Pixel>::type>::pointer,typename color_space_type<Pixel>::type> type;
229 };
230 template <typename Pixel> struct iterator_type_from_pixel<Pixel,true,false,false> {
231     typedef planar_pixel_iterator<typename channel_traits<typename channel_type<Pixel>::type>::const_pointer,typename color_space_type<Pixel>::type> type;
232 };
233 template <typename Pixel, bool IsPlanar, bool IsMutable> struct iterator_type_from_pixel<Pixel,IsPlanar,true,IsMutable> {
234     typedef memory_based_step_iterator<typename iterator_type_from_pixel<Pixel,IsPlanar,false,IsMutable>::type> type;
235 };
236 
237 /// \ingroup TypeFactoryFromElements
238 /// \brief Returns the type of a homogeneous iterator given the channel type, layout, whether it operates on planar data, whether it is a step iterator, and whether it is mutable
239 template <typename T, typename L, bool IsPlanar=false, bool IsStep=false, bool IsMutable=true> struct iterator_type{};
240 template <typename T, typename L> struct iterator_type<T,L,false,false,true > { typedef pixel<T,L>* type; };
241 template <typename T, typename L> struct iterator_type<T,L,false,false,false> { typedef const pixel<T,L>* type; };
242 template <typename T, typename L> struct iterator_type<T,L,true,false,true> { typedef planar_pixel_iterator<T*,typename L::color_space_t> type; };               // TODO: Assert M=identity
243 template <typename T, typename L> struct iterator_type<T,L,true,false,false> { typedef planar_pixel_iterator<const T*,typename L::color_space_t> type; };        // TODO: Assert M=identity
244 template <typename T, typename L, bool IsPlanar, bool IsMutable> struct iterator_type<T,L,IsPlanar,true,IsMutable> {
245     typedef memory_based_step_iterator<typename iterator_type<T,L,IsPlanar,false,IsMutable>::type> type;
246 };
247 
248 /// \brief Given a pixel iterator defining access to pixels along a row, returns the types of the corresponding built-in step_iterator, xy_locator, image_view
249 /// \ingroup TypeFactory
250 template <typename XIterator>
251 struct type_from_x_iterator {
252     typedef memory_based_step_iterator<XIterator>    step_iterator_t;
253     typedef memory_based_2d_locator<step_iterator_t> xy_locator_t;
254     typedef image_view<xy_locator_t>                     view_t;
255 };
256 
257 namespace detail {
258     template <typename BitField, typename FirstBit, typename NumBits>
259     struct packed_channel_reference_type {
260         typedef const packed_channel_reference<BitField,FirstBit::value,NumBits::value,true> type;
261     };
262 
263     template <typename BitField, typename ChannelBitSizesVector>
264     class packed_channel_references_vector_type {
265         // If ChannelBitSizesVector is mpl::vector<int,7,7,2>
266         // Then first_bits_vector will be mpl::vector<int,0,7,14,16>
267         typedef typename mpl::accumulate<ChannelBitSizesVector, mpl::vector1<mpl::int_<0> >,
268             mpl::push_back<mpl::_1, mpl::plus<mpl::back<mpl::_1>, mpl::_2> > >::type first_bits_vector;
269     public:
270         typedef typename mpl::transform<typename mpl::pop_back<first_bits_vector>::type, ChannelBitSizesVector,
271                packed_channel_reference_type<BitField, mpl::_1,mpl::_2> >::type type;
272     };
273 
274 }
275 
276 /// \ingroup TypeFactoryFromElements
277 /// \brief Returns the type of a packed pixel given its bitfield type, the bit size of its channels and its layout.
278 ///
279 /// A packed pixel has channels that cover bit ranges but itself is byte aligned. RGB565 pixel is an example.
280 ///
281 /// The size of ChannelBitSizeVector must equal the number of channels in the given layout
282 /// The sum of bit sizes for all channels must be less than or equal to the number of bits in BitField (and cannot exceed 64).
283 ///  If it is less than the number of bits in BitField, the last bits will be unused.
284 template <typename BitField, typename ChannelBitSizeVector, typename Layout>
285 struct packed_pixel_type {
286     typedef packed_pixel<BitField, typename detail::packed_channel_references_vector_type<BitField,ChannelBitSizeVector>::type, Layout> type;
287 };
288 
289 /// \defgroup TypeFactoryPacked packed_image_type,bit_aligned_image_type
290 /// \ingroup TypeFactoryFromElements
291 /// \brief Returns the type of an image whose channels are not byte-aligned.
292 ///
293 /// A packed image is an image whose pixels are byte aligned, such as "rgb565". <br>
294 /// A bit-aligned image is an image whose pixels are not byte aligned, such as "rgb222". <br>
295 ///
296 /// The sum of the bit sizes of all channels cannot exceed 64.
297 
298 /// \ingroup TypeFactoryPacked
299 /// \brief Returns the type of an interleaved packed image: an image whose channels may not be byte-aligned, but whose pixels are byte aligned.
300 template <typename BitField, typename ChannelBitSizeVector, typename Layout, typename Alloc=std::allocator<unsigned char> >
301 struct packed_image_type {
302     typedef image<typename packed_pixel_type<BitField,ChannelBitSizeVector,Layout>::type,false,Alloc> type;
303 };
304 
305 /// \ingroup TypeFactoryPacked
306 /// \brief Returns the type of a single-channel image given its bitfield type, the bit size of its channel and its layout
307 template <typename BitField, unsigned Size1, typename Layout, typename Alloc=std::allocator<unsigned char> >
308 struct packed_image1_type : public packed_image_type<BitField, mpl::vector1_c<unsigned, Size1>, Layout, Alloc> {};
309 
310 /// \ingroup TypeFactoryPacked
311 /// \brief Returns the type of a two channel image given its bitfield type, the bit size of its channels and its layout
312 template <typename BitField, unsigned Size1, unsigned Size2, typename Layout, typename Alloc=std::allocator<unsigned char> >
313 struct packed_image2_type : public packed_image_type<BitField, mpl::vector2_c<unsigned, Size1, Size2>, Layout, Alloc> {};
314 
315 /// \ingroup TypeFactoryPacked
316 /// \brief Returns the type of a three channel image given its bitfield type, the bit size of its channels and its layout
317 template <typename BitField, unsigned Size1, unsigned Size2, unsigned Size3, typename Layout, typename Alloc=std::allocator<unsigned char> >
318 struct packed_image3_type : public packed_image_type<BitField, mpl::vector3_c<unsigned, Size1, Size2, Size3>, Layout, Alloc> {};
319 
320 /// \ingroup TypeFactoryPacked
321 /// \brief Returns the type of a four channel image given its bitfield type, the bit size of its channels and its layout
322 template <typename BitField, unsigned Size1, unsigned Size2, unsigned Size3, unsigned Size4, typename Layout, typename Alloc=std::allocator<unsigned char> >
323 struct packed_image4_type : public packed_image_type<BitField, mpl::vector4_c<unsigned, Size1, Size2, Size3, Size4>, Layout, Alloc> {};
324 
325 /// \ingroup TypeFactoryPacked
326 /// \brief Returns the type of a five channel image given its bitfield type, the bit size of its channels and its layout
327 template <typename BitField, unsigned Size1, unsigned Size2, unsigned Size3, unsigned Size4, unsigned Size5, typename Layout, typename Alloc=std::allocator<unsigned char> >
328 struct packed_image5_type : public packed_image_type<BitField, mpl::vector5_c<unsigned, Size1, Size2, Size3, Size4, Size5>, Layout, Alloc> {};
329 
330 
331 /// \ingroup TypeFactoryPacked
332 /// \brief Returns the type of a packed image whose pixels may not be byte aligned. For example, an "rgb222" image is bit-aligned because its pixel spans six bits.
333 ///
334 /// Note that the alignment parameter in the constructor of bit-aligned images is in bit units. For example, if you want to construct a bit-aligned
335 /// image whose rows are byte-aligned, use 8 as the alignment parameter, not 1.
336 
337 template <typename ChannelBitSizeVector, typename Layout, typename Alloc=std::allocator<unsigned char> >
338 struct bit_aligned_image_type {
339 private:
340     BOOST_STATIC_CONSTANT(int, bit_size = (mpl::accumulate<ChannelBitSizeVector, mpl::int_<0>, mpl::plus<mpl::_1, mpl::_2> >::type::value));
341     typedef typename detail::min_fast_uint<bit_size+7>::type                        bitfield_t;
342     typedef const bit_aligned_pixel_reference<bitfield_t, ChannelBitSizeVector, Layout, true> bit_alignedref_t;
343 public:
344     typedef image<bit_alignedref_t,false,Alloc> type;
345 };
346 
347 /// \ingroup TypeFactoryPacked
348 /// \brief Returns the type of a single-channel bit-aligned image given the bit size of its channel and its layout
349 template <unsigned Size1, typename Layout, typename Alloc=std::allocator<unsigned char> >
350 struct bit_aligned_image1_type : public bit_aligned_image_type<mpl::vector1_c<unsigned, Size1>, Layout, Alloc> {};
351 
352 /// \ingroup TypeFactoryPacked
353 /// \brief Returns the type of a two channel bit-aligned image given the bit size of its channels and its layout
354 template <unsigned Size1, unsigned Size2, typename Layout, typename Alloc=std::allocator<unsigned char> >
355 struct bit_aligned_image2_type : public bit_aligned_image_type<mpl::vector2_c<unsigned, Size1, Size2>, Layout, Alloc> {};
356 
357 /// \ingroup TypeFactoryPacked
358 /// \brief Returns the type of a three channel bit-aligned image given the bit size of its channels and its layout
359 template <unsigned Size1, unsigned Size2, unsigned Size3, typename Layout, typename Alloc=std::allocator<unsigned char> >
360 struct bit_aligned_image3_type : public bit_aligned_image_type<mpl::vector3_c<unsigned, Size1, Size2, Size3>, Layout, Alloc> {};
361 
362 /// \ingroup TypeFactoryPacked
363 /// \brief Returns the type of a four channel bit-aligned image given the bit size of its channels and its layout
364 template <unsigned Size1, unsigned Size2, unsigned Size3, unsigned Size4, typename Layout, typename Alloc=std::allocator<unsigned char> >
365 struct bit_aligned_image4_type : public bit_aligned_image_type<mpl::vector4_c<unsigned, Size1, Size2, Size3, Size4>, Layout, Alloc> {};
366 
367 /// \ingroup TypeFactoryPacked
368 /// \brief Returns the type of a five channel bit-aligned image given the bit size of its channels and its layout
369 template <unsigned Size1, unsigned Size2, unsigned Size3, unsigned Size4, unsigned Size5, typename Layout, typename Alloc=std::allocator<unsigned char> >
370 struct bit_aligned_image5_type : public bit_aligned_image_type<mpl::vector5_c<unsigned, Size1, Size2, Size3, Size4, Size5>, Layout, Alloc> {};
371 
372 
373 
374 /// \ingroup TypeFactoryFromElements
375 /// \brief Returns the type of a homogeneous pixel given the channel type and layout
376 template <typename Channel, typename Layout>
377 struct pixel_value_type {
378     typedef pixel<Channel,Layout> type;     // by default use gil::pixel. Specializations are provided for
379 };
380 
381 // Specializations for packed channels
382 template <typename BitField, int NumBits, bool IsMutable, typename Layout>
383 struct pixel_value_type<      packed_dynamic_channel_reference<BitField,NumBits,IsMutable>,Layout> :
384     public packed_pixel_type<BitField, mpl::vector1_c<unsigned,NumBits>, Layout> {};
385 template <typename BitField, int NumBits, bool IsMutable, typename Layout>
386 struct pixel_value_type<const packed_dynamic_channel_reference<BitField,NumBits,IsMutable>,Layout> :
387     public packed_pixel_type<BitField, mpl::vector1_c<unsigned,NumBits>, Layout> {};
388 
389 template <typename BitField, int FirstBit, int NumBits, bool IsMutable, typename Layout>
390 struct pixel_value_type<      packed_channel_reference<BitField,FirstBit,NumBits,IsMutable>,Layout> :
391     public packed_pixel_type<BitField, mpl::vector1_c<unsigned,NumBits>, Layout> {};
392 template <typename BitField, int FirstBit, int NumBits, bool IsMutable, typename Layout>
393 struct pixel_value_type<const packed_channel_reference<BitField,FirstBit,NumBits,IsMutable>,Layout> :
394     public packed_pixel_type<BitField, mpl::vector1_c<unsigned,NumBits>, Layout> {};
395 
396 template <int NumBits, typename Layout>
397 struct pixel_value_type<packed_channel_value<NumBits>,Layout> :
398     public packed_pixel_type<typename detail::min_fast_uint<NumBits>::type, mpl::vector1_c<unsigned,NumBits>, Layout> {};
399 
400 
401 /// \ingroup TypeFactoryFromElements
402 /// \brief Returns the type of a homogeneous locator given the channel type, layout, whether it operates on planar data and whether it has a step horizontally
403 template <typename T, typename L, bool IsPlanar=false, bool IsStepX=false, bool IsMutable=true>
404 struct locator_type {
405     typedef typename type_from_x_iterator<typename iterator_type<T,L,IsPlanar,IsStepX,IsMutable>::type>::xy_locator_type type;
406 };
407 
408 /// \ingroup TypeFactoryFromElements
409 /// \brief Returns the type of a homogeneous view given the channel type, layout, whether it operates on planar data and whether it has a step horizontally
410 template <typename T, typename L, bool IsPlanar=false, bool IsStepX=false, bool IsMutable=true>
411 struct view_type {
412     typedef typename type_from_x_iterator<typename iterator_type<T,L,IsPlanar,IsStepX,IsMutable>::type>::view_t type;
413 };
414 
415 /// \ingroup TypeFactoryFromElements
416 /// \brief Returns the type of a homogeneous image given the channel type, layout, and whether it operates on planar data
417 template <typename T, typename L, bool IsPlanar=false, typename Alloc=std::allocator<unsigned char> >
418 struct image_type {
419     typedef image<pixel<T,L>, IsPlanar, Alloc> type;
420 };
421 
422 /// \ingroup TypeFactoryFromPixel
423 /// \brief Returns the type of a view the pixel type, whether it operates on planar data and whether it has a step horizontally
424 template <typename Pixel, bool IsPlanar=false, bool IsStepX=false, bool IsMutable=true>
425 struct view_type_from_pixel {
426     typedef typename type_from_x_iterator<typename iterator_type_from_pixel<Pixel,IsPlanar,IsStepX,IsMutable>::type>::view_t type;
427 };
428 
429 
430 /// \brief Constructs a pixel reference type from a source pixel reference type by changing some of the properties.
431 /// \ingroup TypeFactoryDerived
432 ///  Use use_default for the properties of the source view that you want to keep
433 template <typename Ref, typename T=use_default, typename L=use_default, typename IsPlanar=use_default, typename IsMutable=use_default>
434 class derived_pixel_reference_type {
435     typedef typename remove_reference<Ref>::type pixel_t;
436     typedef typename  mpl::if_<is_same<T, use_default>, typename channel_type<pixel_t>::type,     T >::type channel_t;
437     typedef typename  mpl::if_<is_same<L, use_default>,
438         layout<typename color_space_type<pixel_t>::type, typename channel_mapping_type<pixel_t>::type>, L>::type           layout_t;
439     static const bool mut   =mpl::if_<is_same<IsMutable,use_default>, pixel_reference_is_mutable<Ref>, IsMutable>::type::value;
440     static const bool planar=mpl::if_<is_same<IsPlanar,use_default>,  is_planar<pixel_t>,  IsPlanar>::type::value;
441 public:
442     typedef typename pixel_reference_type<channel_t, layout_t, planar, mut>::type type;
443 };
444 
445 /// \brief Constructs a pixel iterator type from a source pixel iterator type by changing some of the properties.
446 /// \ingroup TypeFactoryDerived
447 ///  Use use_default for the properties of the source view that you want to keep
448 template <typename Iterator, typename T=use_default, typename L=use_default, typename IsPlanar=use_default, typename IsStep=use_default, typename IsMutable=use_default>
449 class derived_iterator_type {
450     typedef typename  mpl::if_<is_same<T ,use_default>, typename channel_type<Iterator>::type,     T >::type channel_t;
451     typedef typename  mpl::if_<is_same<L,use_default>,
452         layout<typename color_space_type<Iterator>::type, typename channel_mapping_type<Iterator>::type>, L>::type layout_t;
453 
454     static const bool mut   =mpl::if_<is_same<IsMutable,use_default>, iterator_is_mutable<Iterator>, IsMutable>::type::value;
455     static const bool planar=mpl::if_<is_same<IsPlanar,use_default>,         is_planar<Iterator>,  IsPlanar>::type::value;
456     static const bool step  =mpl::if_<is_same<IsStep  ,use_default>,  iterator_is_step<Iterator>,    IsStep>::type::value;
457 public:
458     typedef typename iterator_type<channel_t, layout_t, planar, step, mut>::type type;
459 };
460 
461 /// \brief Constructs an image view type from a source view type by changing some of the properties.
462 /// \ingroup TypeFactoryDerived
463 ///  Use use_default for the properties of the source view that you want to keep
464 template <typename View, typename T=use_default, typename L=use_default, typename IsPlanar=use_default, typename StepX=use_default, typename IsMutable=use_default>
465 class derived_view_type {
466     typedef typename  mpl::if_<is_same<T ,use_default>, typename channel_type<View>::type, T>::type channel_t;
467     typedef typename  mpl::if_<is_same<L,use_default>,
468         layout<typename color_space_type<View>::type, typename channel_mapping_type<View>::type>, L>::type layout_t;
469     static const bool mut   =mpl::if_<is_same<IsMutable,use_default>, view_is_mutable<View>, IsMutable>::type::value;
470     static const bool planar=mpl::if_<is_same<IsPlanar,use_default>,  is_planar<View>,  IsPlanar>::type::value;
471     static const bool step  =mpl::if_<is_same<StepX ,use_default>,  view_is_step_in_x<View>,StepX>::type::value;
472 public:
473     typedef typename view_type<channel_t, layout_t, planar, step, mut>::type type;
474 };
475 
476 /// \brief Constructs a homogeneous image type from a source image type by changing some of the properties.
477 /// \ingroup TypeFactoryDerived
478 ///  Use use_default for the properties of the source image that you want to keep
479 template <typename Image, typename T=use_default, typename L=use_default, typename IsPlanar=use_default>
480 class derived_image_type {
481     typedef typename  mpl::if_<is_same<T ,use_default>, typename channel_type<Image>::type,     T >::type channel_t;
482     typedef typename  mpl::if_<is_same<L,use_default>,
483         layout<typename color_space_type<Image>::type, typename channel_mapping_type<Image>::type>, L>::type layout_t;
484     static const bool planar=mpl::if_<is_same<IsPlanar,use_default>,  is_planar<Image>,  IsPlanar>::type::value;
485 public:
486     typedef typename image_type<channel_t, layout_t, planar>::type type;
487 };
488 
489 
490 
491 
492 } }  // namespace boost::gil
493 
494 #endif
495