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1 //
2 // Copyright 2005-2007 Adobe Systems Incorporated
3 //
4 // Distributed under the Boost Software License, Version 1.0
5 // See accompanying file LICENSE_1_0.txt or copy at
6 // http://www.boost.org/LICENSE_1_0.txt
7 //
8 #ifndef BOOST_GIL_METAFUNCTIONS_HPP
9 #define BOOST_GIL_METAFUNCTIONS_HPP
10 
11 #include <boost/gil/channel.hpp>
12 #include <boost/gil/dynamic_step.hpp>
13 #include <boost/gil/concepts.hpp>
14 #include <boost/gil/concepts/detail/type_traits.hpp>
15 #include <boost/gil/detail/mp11.hpp>
16 
17 #include <iterator>
18 #include <type_traits>
19 
20 namespace boost { namespace gil {
21 
22 // forward declarations
23 template <typename T, typename L> struct pixel;
24 template <typename BitField,typename ChannelRefs,typename Layout> struct packed_pixel;
25 template <typename T, typename C> struct planar_pixel_reference;
26 template <typename IC, typename C> struct planar_pixel_iterator;
27 template <typename I> class memory_based_step_iterator;
28 template <typename I> class memory_based_2d_locator;
29 template <typename L> class image_view;
30 template <typename Pixel, bool IsPlanar, typename Alloc> class image;
31 template <typename T> struct channel_type;
32 template <typename T> struct color_space_type;
33 template <typename T> struct channel_mapping_type;
34 template <typename It> struct is_iterator_adaptor;
35 template <typename It> struct iterator_adaptor_get_base;
36 template <typename BitField, typename ChannelBitSizes, typename Layout, bool IsMutable> struct bit_aligned_pixel_reference;
37 
38 //////////////////////////////////////////////////
39 ///
40 ///  TYPE ANALYSIS METAFUNCTIONS
41 ///  Predicate metafunctions determining properties of GIL types
42 ///
43 //////////////////////////////////////////////////
44 
45 
46 /// \defgroup GILIsBasic xxx_is_basic
47 /// \ingroup TypeAnalysis
48 /// \brief Determines if GIL constructs are basic.
49 ///    Basic constructs are the ones that can be generated with the type
50 ///    factory methods pixel_reference_type, iterator_type, locator_type, view_type and image_type
51 ///    They can be mutable/immutable, planar/interleaved, step/nonstep. They must use GIL-provided models.
52 
53 /// \brief Determines if a given pixel reference is basic
54 ///    Basic references must use gil::pixel& (if interleaved), gil::planar_pixel_reference (if planar). They must use the standard constness rules.
55 /// \ingroup GILIsBasic
56 template <typename PixelRef>
57 struct pixel_reference_is_basic : public std::false_type {};
58 
59 template <typename T, typename L>
60 struct pixel_reference_is_basic<pixel<T, L>&> : std::true_type {};
61 
62 template <typename T, typename L>
63 struct pixel_reference_is_basic<const pixel<T, L>&> : std::true_type {};
64 
65 template <typename TR, typename CS>
66 struct pixel_reference_is_basic<planar_pixel_reference<TR, CS>> : std::true_type {};
67 
68 template <typename TR, typename CS>
69 struct pixel_reference_is_basic<const planar_pixel_reference<TR, CS>> : std::true_type {};
70 
71 /// \brief Determines if a given pixel iterator is basic
72 ///    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.
73 /// \ingroup GILIsBasic
74 template <typename Iterator>
75 struct iterator_is_basic : std::false_type {};
76 
77 /// \tparam T mutable interleaved pixel type
78 template <typename T, typename L>
79 struct iterator_is_basic<pixel<T, L>*> : std::true_type {};
80 
81 /// \tparam T immutable interleaved pixel type
82 template <typename T, typename L>
83 struct iterator_is_basic<pixel<T, L> const*> : std::true_type {};
84 
85 /// \tparam T mutable planar pixel type
86 template <typename T, typename CS>
87 struct iterator_is_basic<planar_pixel_iterator<T*, CS>> : std::true_type {};
88 
89 /// \tparam T immutable planar pixel type
90 template <typename T, typename CS>
91 struct iterator_is_basic<planar_pixel_iterator<T const*, CS>> : std::true_type {};
92 
93 /// \tparam T mutable interleaved step
94 template <typename T, typename L>
95 struct iterator_is_basic<memory_based_step_iterator<pixel<T, L>*>> : std::true_type {};
96 
97 /// \tparam T immutable interleaved step
98 template <typename T, typename L>
99 struct iterator_is_basic<memory_based_step_iterator<pixel<T, L> const*>> : std::true_type {};
100 
101 /// \tparam T mutable planar step
102 template <typename T, typename CS>
103 struct iterator_is_basic<memory_based_step_iterator<planar_pixel_iterator<T*, CS>>>
104     : std::true_type
105 {};
106 
107 /// \tparam T immutable planar step
108 template <typename T, typename CS>
109 struct iterator_is_basic<memory_based_step_iterator<planar_pixel_iterator<T const*, CS>>>
110     : std::true_type
111 {};
112 
113 
114 /// \ingroup GILIsBasic
115 /// \brief Determines if a given locator is basic. A basic locator is memory-based and has basic x_iterator and y_iterator
116 template <typename Loc>
117 struct locator_is_basic : std::false_type {};
118 
119 template <typename Iterator>
120 struct locator_is_basic
121     <
122         memory_based_2d_locator<memory_based_step_iterator<Iterator>>
123     > : iterator_is_basic<Iterator>
124 {};
125 
126 /// \ingroup GILIsBasic
127 /// \brief Basic views must be over basic locators
128 template <typename View>
129 struct view_is_basic : std::false_type {};
130 
131 template <typename Loc>
132 struct view_is_basic<image_view<Loc>> : locator_is_basic<Loc> {};
133 
134 /// \ingroup GILIsBasic
135 /// \brief Basic images must use basic views and std::allocator
136 template <typename Img>
137 struct image_is_basic : std::false_type {};
138 
139 template <typename Pixel, bool IsPlanar, typename Alloc>
140 struct image_is_basic<image<Pixel, IsPlanar, Alloc>> : std::true_type {};
141 
142 
143 /// \defgroup GILIsStep xxx_is_step
144 /// \ingroup TypeAnalysis
145 /// \brief Determines if the given iterator/locator/view has a step that could be set dynamically
146 
147 template <typename I>
148 struct iterator_is_step;
149 
150 namespace detail {
151 
152 template <typename It, bool IsBase, bool EqualsStepType>
153 struct iterator_is_step_impl;
154 
155 // iterator that has the same type as its dynamic_x_step_type must be a step iterator
156 template <typename It, bool IsBase>
157 struct iterator_is_step_impl<It, IsBase, true> : std::true_type {};
158 
159 // base iterator can never be a step iterator
160 template <typename It>
161 struct iterator_is_step_impl<It, true, false> : std::false_type {};
162 
163 // for an iterator adaptor, see if its base is step
164 template <typename It>
165 struct iterator_is_step_impl<It, false, false>
166     : public iterator_is_step<typename iterator_adaptor_get_base<It>::type> {};
167 
168 } // namespace detail
169 
170 /// \ingroup GILIsStep
171 /// \brief Determines if the given iterator has a step that could be set dynamically
172 template <typename I>
173 struct iterator_is_step
174     : detail::iterator_is_step_impl
175     <
176         I,
177         !is_iterator_adaptor<I>::value,
178         std::is_same<I, typename dynamic_x_step_type<I>::type
179     >::value
180 >
181 {};
182 
183 /// \ingroup GILIsStep
184 /// \brief Determines if the given locator has a horizontal step that could be set dynamically
185 template <typename L> struct locator_is_step_in_x : public iterator_is_step<typename L::x_iterator> {};
186 
187 /// \ingroup GILIsStep
188 /// \brief Determines if the given locator has a vertical step that could be set dynamically
189 template <typename L> struct locator_is_step_in_y : public iterator_is_step<typename L::y_iterator> {};
190 
191 /// \ingroup GILIsStep
192 /// \brief Determines if the given view has a horizontal step that could be set dynamically
193 template <typename V> struct view_is_step_in_x : public locator_is_step_in_x<typename V::xy_locator> {};
194 
195 /// \ingroup GILIsStep
196 /// \brief Determines if the given view has a vertical step that could be set dynamically
197 template <typename V> struct view_is_step_in_y : public locator_is_step_in_y<typename V::xy_locator> {};
198 
199 /// \brief Determines whether the given pixel reference is a proxy class or a native C++ reference
200 /// \ingroup TypeAnalysis
201 template <typename PixelReference>
202 struct pixel_reference_is_proxy
203     : mp11::mp_not
204     <
205         std::is_same
206         <
207             typename detail::remove_const_and_reference<PixelReference>::type,
208             typename detail::remove_const_and_reference<PixelReference>::type::value_type
209         >
210     >
211 {};
212 
213 /// \brief Given a model of a pixel, determines whether the model represents a pixel reference (as opposed to pixel value)
214 /// \ingroup TypeAnalysis
215 template <typename Pixel>
216 struct pixel_is_reference
217     : mp11::mp_or<is_reference<Pixel>, pixel_reference_is_proxy<Pixel>> {};
218 
219 /// \defgroup GILIsMutable xxx_is_mutable
220 /// \ingroup TypeAnalysis
221 /// \brief Determines if the given pixel reference/iterator/locator/view is mutable (i.e. its pixels can be changed)
222 
223 /// \ingroup GILIsMutable
224 /// \brief Determines if the given pixel reference is mutable (i.e. its channels can be changed)
225 ///
226 /// Note that built-in C++ references obey the const qualifier but reference proxy classes do not.
227 template <typename R>
228 struct pixel_reference_is_mutable
229     : std::integral_constant<bool, std::remove_reference<R>::type::is_mutable>
230 {};
231 
232 template <typename R>
233 struct pixel_reference_is_mutable<R const&>
234     : mp11::mp_and<pixel_reference_is_proxy<R>, pixel_reference_is_mutable<R>>
235 {};
236 
237 /// \ingroup GILIsMutable
238 /// \brief Determines if the given locator is mutable (i.e. its pixels can be changed)
239 template <typename L> struct locator_is_mutable : public iterator_is_mutable<typename L::x_iterator> {};
240 /// \ingroup GILIsMutable
241 /// \brief Determines if the given view is mutable (i.e. its pixels can be changed)
242 template <typename V> struct view_is_mutable : public iterator_is_mutable<typename V::x_iterator> {};
243 
244 
245 //////////////////////////////////////////////////
246 ///
247 ///  TYPE FACTORY METAFUNCTIONS
248 ///  Metafunctions returning GIL types from other GIL types
249 ///
250 //////////////////////////////////////////////////
251 
252 /// \defgroup TypeFactoryFromElements xxx_type
253 /// \ingroup TypeFactory
254 /// \brief Returns the type of a homogeneous GIL construct given its elements (channel, layout, whether it is planar, step, mutable, etc.)
255 
256 /// \defgroup TypeFactoryFromPixel xxx_type_from_pixel
257 /// \ingroup TypeFactory
258 /// \brief Returns the type of a GIL construct given its pixel type, whether it is planar, step, mutable, etc.
259 
260 /// \defgroup TypeFactoryDerived derived_xxx_type
261 /// \ingroup TypeFactory
262 /// \brief Returns the type of a homogeneous GIL construct given a related construct by changing some of its properties
263 
264 /// \ingroup TypeFactoryFromElements
265 /// \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
266 template <typename T, typename L, bool IsPlanar=false, bool IsMutable=true> struct pixel_reference_type{};
267 template <typename T, typename L> struct pixel_reference_type<T,L,false,true > { using type = pixel<T,L>&; };
268 template <typename T, typename L> struct pixel_reference_type<T,L,false,false> { using type = pixel<T,L> const&; };
269 template <typename T, typename L> struct pixel_reference_type<T,L,true,true> { using type = planar_pixel_reference<typename channel_traits<T>::reference,typename color_space_type<L>::type> const; };       // TODO: Assert M=identity
270 template <typename T, typename L> struct pixel_reference_type<T,L,true,false> { using type = planar_pixel_reference<typename channel_traits<T>::const_reference,typename color_space_type<L>::type> const; };// TODO: Assert M=identity
271 
272 /// \ingroup TypeFactoryFromPixel
273 /// \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
274 template <typename Pixel, bool IsPlanar=false, bool IsStep=false, bool IsMutable=true> struct iterator_type_from_pixel{};
275 template <typename Pixel> struct iterator_type_from_pixel<Pixel,false,false,true > { using type = Pixel *; };
276 template <typename Pixel> struct iterator_type_from_pixel<Pixel,false,false,false> { using type = const Pixel *; };
277 template <typename Pixel> struct iterator_type_from_pixel<Pixel,true,false,true> {
278     using type = planar_pixel_iterator<typename channel_traits<typename channel_type<Pixel>::type>::pointer,typename color_space_type<Pixel>::type>;
279 };
280 template <typename Pixel> struct iterator_type_from_pixel<Pixel,true,false,false> {
281     using type = planar_pixel_iterator<typename channel_traits<typename channel_type<Pixel>::type>::const_pointer,typename color_space_type<Pixel>::type>;
282 };
283 template <typename Pixel, bool IsPlanar, bool IsMutable> struct iterator_type_from_pixel<Pixel,IsPlanar,true,IsMutable> {
284     using type = memory_based_step_iterator<typename iterator_type_from_pixel<Pixel,IsPlanar,false,IsMutable>::type>;
285 };
286 
287 /// \ingroup TypeFactoryFromElements
288 /// \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
289 template <typename T, typename L, bool IsPlanar=false, bool IsStep=false, bool IsMutable=true> struct iterator_type{};
290 template <typename T, typename L> struct iterator_type<T,L,false,false,true > { using type = pixel<T,L>*; };
291 template <typename T, typename L> struct iterator_type<T,L,false,false,false> { using type = pixel<T,L> const*; };
292 template <typename T, typename L> struct iterator_type<T,L,true,false,true> { using type = planar_pixel_iterator<T*,typename L::color_space_t>; };               // TODO: Assert M=identity
293 template <typename T, typename L> struct iterator_type<T,L,true,false,false> { using type = planar_pixel_iterator<const T*,typename L::color_space_t>; };        // TODO: Assert M=identity
294 template <typename T, typename L, bool IsPlanar, bool IsMutable> struct iterator_type<T,L,IsPlanar,true,IsMutable> {
295     using type = memory_based_step_iterator<typename iterator_type<T,L,IsPlanar,false,IsMutable>::type>;
296 };
297 
298 /// \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
299 /// \ingroup TypeFactory
300 template <typename XIterator>
301 struct type_from_x_iterator
302 {
303     using step_iterator_t = memory_based_step_iterator<XIterator>;
304     using xy_locator_t = memory_based_2d_locator<step_iterator_t>;
305     using view_t = image_view<xy_locator_t>;
306 };
307 
308 namespace detail {
309 
310 template <typename BitField, typename FirstBit, typename NumBits>
311 struct packed_channel_reference_type
312 {
313     using type = packed_channel_reference
314         <
315             BitField, FirstBit::value, NumBits::value, true
316         > const;
317 };
318 
319 template <typename BitField, typename ChannelBitSizes>
320 class packed_channel_references_vector_type
321 {
322     template <typename FirstBit, typename NumBits>
323     using reference_type = typename packed_channel_reference_type<BitField, FirstBit, NumBits>::type;
324 
325     // If ChannelBitSizesVector is mp11::mp_list_c<int,7,7,2>
326     // Then first_bits_vector will be mp11::mp_list_c<int,0,7,14,16>
327     using first_bit_list = mp11::mp_fold_q
328         <
329             ChannelBitSizes,
330             mp11::mp_list<std::integral_constant<int, 0>>,
331             mp11::mp_bind
332             <
333                 mp11::mp_push_back,
334                 mp11::_1,
335                 mp11::mp_bind
336                 <
337                     mp11::mp_plus,
338                     mp11::mp_bind<mp_back, mp11::_1>,
339                     mp11::_2
340                 >
341             >
342         >;
343 
344     static_assert(mp11::mp_at_c<first_bit_list, 0>::value == 0, "packed channel first bit must be 0");
345 
346 public:
347     using type = mp11::mp_transform
348         <
349             reference_type,
350             mp_pop_back<first_bit_list>,
351             ChannelBitSizes
352         >;
353 };
354 
355 } // namespace detail
356 
357 /// \ingroup TypeFactoryFromElements
358 /// \brief Returns the type of a packed pixel given its bitfield type, the bit size of its channels and its layout.
359 ///
360 /// A packed pixel has channels that cover bit ranges but itself is byte aligned. RGB565 pixel is an example.
361 ///
362 /// The size of ChannelBitSizes must equal the number of channels in the given layout
363 /// 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).
364 ///  If it is less than the number of bits in BitField, the last bits will be unused.
365 template <typename BitField, typename ChannelBitSizes, typename Layout>
366 struct packed_pixel_type
367 {
368     using type = packed_pixel
369         <
370             BitField,
371             typename detail::packed_channel_references_vector_type
372             <
373                 BitField,
374                 ChannelBitSizes
375             >::type,
376         Layout>;
377 };
378 
379 /// \defgroup TypeFactoryPacked packed_image_type,bit_aligned_image_type
380 /// \ingroup TypeFactoryFromElements
381 /// \brief Returns the type of an image whose channels are not byte-aligned.
382 ///
383 /// A packed image is an image whose pixels are byte aligned, such as "rgb565". <br>
384 /// A bit-aligned image is an image whose pixels are not byte aligned, such as "rgb222". <br>
385 ///
386 /// The sum of the bit sizes of all channels cannot exceed 64.
387 
388 /// \ingroup TypeFactoryPacked
389 /// \brief Returns the type of an interleaved packed image: an image whose channels may not be byte-aligned, but whose pixels are byte aligned.
390 template <typename BitField, typename ChannelBitSizes, typename Layout, typename Alloc=std::allocator<unsigned char>>
391 struct packed_image_type
392 {
393     using type = image<typename packed_pixel_type<BitField,ChannelBitSizes,Layout>::type,false,Alloc>;
394 };
395 
396 /// \ingroup TypeFactoryPacked
397 /// \brief Returns the type of a single-channel image given its bitfield type, the bit size of its channel and its layout
398 template <typename BitField, unsigned Size1, typename Layout, typename Alloc = std::allocator<unsigned char>>
399 struct packed_image1_type
400     : packed_image_type<BitField, mp11::mp_list_c<unsigned, Size1>, Layout, Alloc>
401 {};
402 
403 /// \ingroup TypeFactoryPacked
404 /// \brief Returns the type of a two channel image given its bitfield type, the bit size of its channels and its layout
405 template <typename BitField, unsigned Size1, unsigned Size2, typename Layout, typename Alloc = std::allocator<unsigned char>>
406 struct packed_image2_type
407     : packed_image_type<BitField, mp11::mp_list_c<unsigned, Size1, Size2>, Layout, Alloc>
408 {};
409 
410 /// \ingroup TypeFactoryPacked
411 /// \brief Returns the type of a three channel image given its bitfield type, the bit size of its channels and its layout
412 template <typename BitField, unsigned Size1, unsigned Size2, unsigned Size3, typename Layout, typename Alloc = std::allocator<unsigned char>>
413 struct packed_image3_type
414     : packed_image_type<BitField, mp11::mp_list_c<unsigned, Size1, Size2, Size3>, Layout, Alloc>
415 {};
416 
417 /// \ingroup TypeFactoryPacked
418 /// \brief Returns the type of a four channel image given its bitfield type, the bit size of its channels and its layout
419 template <typename BitField, unsigned Size1, unsigned Size2, unsigned Size3, unsigned Size4, typename Layout, typename Alloc = std::allocator<unsigned char>>
420 struct packed_image4_type
421     : packed_image_type<BitField, mp11::mp_list_c<unsigned, Size1, Size2, Size3, Size4>, Layout, Alloc>
422 {};
423 
424 /// \ingroup TypeFactoryPacked
425 /// \brief Returns the type of a five channel image given its bitfield type, the bit size of its channels and its layout
426 template <typename BitField, unsigned Size1, unsigned Size2, unsigned Size3, unsigned Size4, unsigned Size5, typename Layout, typename Alloc = std::allocator<unsigned char>>
427 struct packed_image5_type
428     : packed_image_type<BitField, mp11::mp_list_c<unsigned, Size1, Size2, Size3, Size4, Size5>, Layout, Alloc> {};
429 
430 
431 /// \ingroup TypeFactoryPacked
432 /// \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.
433 ///
434 /// 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
435 /// image whose rows are byte-aligned, use 8 as the alignment parameter, not 1.
436 ///
437 template
438 <
439     typename ChannelBitSizes,
440     typename Layout,
441     typename Alloc = std::allocator<unsigned char>
442 >
443 struct bit_aligned_image_type
444 {
445 private:
446 
447     static constexpr int bit_size =
448         mp11::mp_fold
449         <
450             ChannelBitSizes,
451             std::integral_constant<int, 0>,
452             mp11::mp_plus
453         >::value;
454 
455     using bitfield_t = typename detail::min_fast_uint<bit_size + 7>::type;
456     using bit_alignedref_t = bit_aligned_pixel_reference<bitfield_t, ChannelBitSizes, Layout, true> const;
457 
458 public:
459     using type = image<bit_alignedref_t,false,Alloc>;
460 };
461 
462 /// \ingroup TypeFactoryPacked
463 /// \brief Returns the type of a single-channel bit-aligned image given the bit size of its channel and its layout
464 template <unsigned Size1, typename Layout, typename Alloc = std::allocator<unsigned char>>
465 struct bit_aligned_image1_type : bit_aligned_image_type<mp11::mp_list_c<unsigned, Size1>, Layout, Alloc> {};
466 
467 /// \ingroup TypeFactoryPacked
468 /// \brief Returns the type of a two channel bit-aligned image given the bit size of its channels and its layout
469 template <unsigned Size1, unsigned Size2, typename Layout, typename Alloc = std::allocator<unsigned char>>
470 struct bit_aligned_image2_type : bit_aligned_image_type<mp11::mp_list_c<unsigned, Size1, Size2>, Layout, Alloc> {};
471 
472 /// \ingroup TypeFactoryPacked
473 /// \brief Returns the type of a three channel bit-aligned image given the bit size of its channels and its layout
474 template <unsigned Size1, unsigned Size2, unsigned Size3, typename Layout, typename Alloc = std::allocator<unsigned char>>
475 struct bit_aligned_image3_type : bit_aligned_image_type<mp11::mp_list_c<unsigned, Size1, Size2, Size3>, Layout, Alloc> {};
476 
477 /// \ingroup TypeFactoryPacked
478 /// \brief Returns the type of a four channel bit-aligned image given the bit size of its channels and its layout
479 template <unsigned Size1, unsigned Size2, unsigned Size3, unsigned Size4, typename Layout, typename Alloc = std::allocator<unsigned char>>
480 struct bit_aligned_image4_type : bit_aligned_image_type<mp11::mp_list_c<unsigned, Size1, Size2, Size3, Size4>, Layout, Alloc> {};
481 
482 /// \ingroup TypeFactoryPacked
483 /// \brief Returns the type of a five channel bit-aligned image given the bit size of its channels and its layout
484 template <unsigned Size1, unsigned Size2, unsigned Size3, unsigned Size4, unsigned Size5, typename Layout, typename Alloc = std::allocator<unsigned char>>
485 struct bit_aligned_image5_type : bit_aligned_image_type<mp11::mp_list_c<unsigned, Size1, Size2, Size3, Size4, Size5>, Layout, Alloc> {};
486 
487 
488 /// \ingroup TypeFactoryFromElements
489 /// \brief Returns the type of a homogeneous pixel given the channel type and layout
490 template <typename Channel, typename Layout>
491 struct pixel_value_type
492 {
493     // by default use gil::pixel. Specializations are provided for
494     using type = pixel<Channel, Layout>;
495 };
496 
497 // Specializations for packed channels
498 template <typename BitField, int NumBits, bool IsMutable, typename Layout>
499 struct pixel_value_type<packed_dynamic_channel_reference<BitField, NumBits, IsMutable>, Layout>
500     : packed_pixel_type<BitField, mp11::mp_list_c<unsigned, NumBits>, Layout>
501 {};
502 
503 template <typename BitField, int NumBits, bool IsMutable, typename Layout>
504 struct pixel_value_type<packed_dynamic_channel_reference<BitField, NumBits, IsMutable> const, Layout>
505     : packed_pixel_type<BitField, mp11::mp_list_c<unsigned, NumBits>, Layout>
506 {};
507 
508 template <typename BitField, int FirstBit, int NumBits, bool IsMutable, typename Layout>
509 struct pixel_value_type<packed_channel_reference<BitField, FirstBit, NumBits, IsMutable>, Layout>
510     : packed_pixel_type<BitField, mp11::mp_list_c<unsigned, NumBits>, Layout>
511 {};
512 
513 template <typename BitField, int FirstBit, int NumBits, bool IsMutable, typename Layout>
514 struct pixel_value_type<packed_channel_reference<BitField, FirstBit, NumBits, IsMutable> const, Layout>
515     : packed_pixel_type<BitField, mp11::mp_list_c<unsigned, NumBits>, Layout>
516 {};
517 
518 template <int NumBits, typename Layout>
519 struct pixel_value_type<packed_channel_value<NumBits>, Layout>
520     : packed_pixel_type<typename detail::min_fast_uint<NumBits>::type, mp11::mp_list_c<unsigned, NumBits>, Layout>
521 {};
522 
523 /// \ingroup TypeFactoryFromElements
524 /// \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
525 template <typename T, typename L, bool IsPlanar = false, bool IsStepX = false, bool IsMutable = true>
526 struct locator_type
527 {
528     using type = typename type_from_x_iterator
529         <
530             typename iterator_type<T, L, IsPlanar, IsStepX, IsMutable>::type
531         >::xy_locator_type;
532 };
533 
534 /// \ingroup TypeFactoryFromElements
535 /// \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
536 template <typename T, typename L, bool IsPlanar = false, bool IsStepX = false, bool IsMutable = true>
537 struct view_type
538 {
539     using type = typename type_from_x_iterator
540         <
541             typename iterator_type<T, L, IsPlanar, IsStepX, IsMutable>::type
542         >::view_t;
543 };
544 
545 /// \ingroup TypeFactoryFromElements
546 /// \brief Returns the type of a homogeneous image given the channel type, layout, and whether it operates on planar data
547 template <typename T, typename L, bool IsPlanar = false, typename Alloc = std::allocator<unsigned char>>
548 struct image_type
549 {
550     using type = image<pixel<T, L>, IsPlanar, Alloc>;
551 };
552 
553 /// \ingroup TypeFactoryFromPixel
554 /// \brief Returns the type of a view the pixel type, whether it operates on planar data and whether it has a step horizontally
555 template <typename Pixel, bool IsPlanar=false, bool IsStepX=false, bool IsMutable=true>
556 struct view_type_from_pixel {
557     using type = typename type_from_x_iterator<typename iterator_type_from_pixel<Pixel,IsPlanar,IsStepX,IsMutable>::type>::view_t;
558 };
559 
560 
561 /// \brief Constructs a pixel reference type from a source pixel reference type by changing some of the properties.
562 /// \ingroup TypeFactoryDerived
563 ///  Use use_default for the properties of the source view that you want to keep
564 template
565 <
566         typename Ref,
567         typename T = use_default,
568         typename L = use_default,
569         typename IsPlanar = use_default,
570         typename IsMutable = use_default>
571 class derived_pixel_reference_type
572 {
573     using pixel_t = typename std::remove_reference<Ref>::type;
574 
575     using channel_t = typename mp11::mp_if
576         <
577             std::is_same<T, use_default>,
578             typename channel_type<pixel_t>::type,
579             T
580         >::type;
581 
582     using layout_t = typename  mp11::mp_if
583         <
584             std::is_same<L, use_default>,
585             layout
586             <
587                 typename color_space_type<pixel_t>::type,
588                 typename channel_mapping_type<pixel_t>::type
589             >,
590             L
591         >::type;
592 
593     static bool const mut = mp11::mp_if
594         <
595             std::is_same<IsMutable, use_default>,
596             pixel_reference_is_mutable<Ref>,
597             IsMutable
598         >::value;
599 
600     static bool const planar = mp11::mp_if
601         <
602             std::is_same<IsPlanar, use_default>,
603             is_planar<pixel_t>,
604             IsPlanar
605         >::value;
606 
607 public:
608     using type = typename pixel_reference_type<channel_t, layout_t, planar, mut>::type;
609 };
610 
611 /// \brief Constructs a pixel iterator type from a source pixel iterator type by changing some of the properties.
612 /// \ingroup TypeFactoryDerived
613 ///  Use use_default for the properties of the source view that you want to keep
614 template
615 <
616     typename Iterator,
617     typename T = use_default,
618     typename L = use_default,
619     typename IsPlanar = use_default,
620     typename IsStep = use_default,
621     typename IsMutable = use_default
622 >
623 class derived_iterator_type
624 {
625     using channel_t = typename mp11::mp_if
626         <
627             std::is_same<T, use_default>,
628             typename channel_type<Iterator>::type,
629             T
630         >::type;
631 
632     using layout_t = typename mp11::mp_if
633         <
634             std::is_same<L, use_default>,
635             layout
636             <
637                 typename color_space_type<Iterator>::type,
638                 typename channel_mapping_type<Iterator>::type
639             >,
640             L
641         >::type;
642 
643     static const bool mut = mp11::mp_if
644         <
645             std::is_same<IsMutable, use_default>,
646             iterator_is_mutable<Iterator>,
647             IsMutable
648         >::value;
649 
650     static bool const planar = mp11::mp_if
651         <
652             std::is_same<IsPlanar, use_default>,
653             is_planar<Iterator>,
654             IsPlanar
655         >::value;
656 
657     static bool const step = mp11::mp_if
658         <
659             std::is_same<IsStep, use_default>,
660             iterator_is_step<Iterator>,
661             IsStep
662         >::type::value;
663 
664 public:
665     using type = typename iterator_type<channel_t, layout_t, planar, step, mut>::type;
666 };
667 
668 /// \brief Constructs an image view type from a source view type by changing some of the properties.
669 /// \ingroup TypeFactoryDerived
670 ///  Use use_default for the properties of the source view that you want to keep
671 template <typename View, typename T = use_default, typename L = use_default, typename IsPlanar = use_default, typename StepX = use_default, typename IsMutable = use_default>
672 class derived_view_type
673 {
674     using channel_t = typename mp11::mp_if
675         <
676             std::is_same<T, use_default>,
677             typename channel_type<View>::type,
678             T
679         >;
680 
681     using layout_t = typename mp11::mp_if
682         <
683             std::is_same<L, use_default>,
684             layout
685             <
686                 typename color_space_type<View>::type,
687                 typename channel_mapping_type<View>::type
688             >,
689             L
690         >;
691 
692     static bool const mut = mp11::mp_if
693         <
694             std::is_same<IsMutable, use_default>,
695             view_is_mutable<View>,
696             IsMutable
697         >::value;
698 
699     static bool const planar = mp11::mp_if
700         <
701             std::is_same<IsPlanar, use_default>,
702             is_planar<View>,
703             IsPlanar
704         >::value;
705 
706     static bool const step = mp11::mp_if
707         <
708             std::is_same<StepX, use_default>,
709             view_is_step_in_x<View>,
710             StepX
711         >::value;
712 
713 public:
714     using type = typename view_type<channel_t, layout_t, planar, step, mut>::type;
715 };
716 
717 /// \brief Constructs a homogeneous image type from a source image type by changing some of the properties.
718 /// \ingroup TypeFactoryDerived
719 ///  Use use_default for the properties of the source image that you want to keep
720 template <typename Image, typename T = use_default, typename L = use_default, typename IsPlanar = use_default>
721 class derived_image_type
722 {
723     using channel_t = typename mp11::mp_if
724         <
725             std::is_same<T, use_default>,
726             typename channel_type<Image>::type,
727             T
728         >::type;
729 
730     using layout_t = typename mp11::mp_if
731         <
732             std::is_same<L, use_default>,
733             layout
734             <
735                 typename color_space_type<Image>::type,
736                 typename channel_mapping_type<Image>::type>,
737                 L
738             >::type;
739 
740     static bool const planar = mp11::mp_if
741         <
742             std::is_same<IsPlanar, use_default>,
743             is_planar<Image>,
744             IsPlanar
745         >::value;
746 
747 public:
748     using type = typename image_type<channel_t, layout_t, planar>::type;
749 };
750 
751 }}  // namespace boost::gil
752 
753 #endif
754