]>
Commit | Line | Data |
---|---|---|
7c673cae FG |
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_IMAGE_VIEW_FACTORY_HPP | |
14 | #define GIL_IMAGE_VIEW_FACTORY_HPP | |
15 | ||
16 | /*! | |
17 | /// \file | |
18 | /// \brief Methods for constructing image views from raw data or other image views | |
19 | /// \author Lubomir Bourdev and Hailin Jin \n | |
20 | /// Adobe Systems Incorporated | |
21 | /// \date 2005-2007 \n Last updated on March 9, 2007 | |
22 | /// Methods for creating shallow image views from raw pixel data or from other image views - | |
23 | /// flipping horizontally or vertically, axis-aligned rotation, a subimage, subsampled | |
24 | /// or n-th channel image view. Derived image views are shallow copies and are fast to construct. | |
25 | */ | |
26 | ||
27 | #include <cassert> | |
28 | #include <cstddef> | |
29 | #include "gil_config.hpp" | |
30 | #include "metafunctions.hpp" | |
31 | #include "gray.hpp" | |
32 | #include "color_convert.hpp" | |
33 | ||
34 | /// \defgroup ImageViewConstructors Image View From Raw Data | |
35 | /// \ingroup ImageViewAlgorithm | |
36 | /// \brief Methods for constructing image views from raw data and for getting raw data from views | |
37 | ||
38 | /// \defgroup ImageViewTransformations Image View Transformations | |
39 | /// \ingroup ImageViewAlgorithm | |
40 | /// \brief Methods for constructing one image view from another | |
41 | ||
42 | namespace boost { namespace gil { | |
43 | struct default_color_converter; | |
44 | ||
45 | template <typename T> struct dynamic_x_step_type; | |
46 | template <typename T> struct dynamic_y_step_type; | |
47 | template <typename T> struct transposed_type; | |
48 | ||
49 | /// \brief Returns the type of a view that has a dynamic step along both X and Y | |
50 | /// \ingroup ImageViewTransformations | |
51 | template <typename View> | |
52 | struct dynamic_xy_step_type : public dynamic_y_step_type<typename dynamic_x_step_type<View>::type> {}; | |
53 | ||
54 | /// \brief Returns the type of a transposed view that has a dynamic step along both X and Y | |
55 | /// \ingroup ImageViewTransformations | |
56 | template <typename View> | |
57 | struct dynamic_xy_step_transposed_type : public dynamic_xy_step_type<typename transposed_type<View>::type> {}; | |
58 | ||
59 | ||
60 | /// \ingroup ImageViewConstructors | |
61 | /// \brief Constructing image views from raw interleaved pixel data | |
62 | template <typename Iterator> | |
63 | typename type_from_x_iterator<Iterator>::view_t | |
64 | interleaved_view(std::size_t width, std::size_t height, | |
65 | Iterator pixels, std::ptrdiff_t rowsize_in_bytes) { | |
66 | typedef typename type_from_x_iterator<Iterator>::view_t RView; | |
67 | return RView(width, height, typename RView::locator(pixels, rowsize_in_bytes)); | |
68 | } | |
69 | ||
70 | /// \ingroup ImageViewConstructors | |
71 | /// \brief Constructing image views from raw interleaved pixel data | |
72 | template <typename Iterator> | |
73 | typename type_from_x_iterator<Iterator>::view_t | |
74 | interleaved_view(point2<std::size_t> dim, | |
75 | Iterator pixels, std::ptrdiff_t rowsize_in_bytes) { | |
76 | typedef typename type_from_x_iterator<Iterator>::view_t RView; | |
77 | return RView(dim, typename RView::locator(pixels, rowsize_in_bytes)); | |
78 | } | |
79 | ||
80 | ///////////////////////////// | |
81 | // interleaved_view_get_raw_data, planar_view_get_raw_data - return pointers to the raw data (the channels) of a basic homogeneous view. | |
82 | ///////////////////////////// | |
83 | ||
84 | namespace detail { | |
85 | template <typename View, bool IsMutable> struct channel_pointer_type_impl; | |
86 | ||
87 | template <typename View> struct channel_pointer_type_impl<View, true> { | |
88 | typedef typename channel_type<View>::type* type; | |
89 | }; | |
90 | template <typename View> struct channel_pointer_type_impl<View, false> { | |
91 | typedef const typename channel_type<View>::type* type; | |
92 | }; | |
93 | ||
94 | template <typename View> struct channel_pointer_type | |
95 | : public channel_pointer_type_impl<View, view_is_mutable<View>::value> {}; | |
96 | } // namespace detail | |
97 | ||
98 | /// \ingroup ImageViewConstructors | |
99 | /// \brief Returns C pointer to the the channels of an interleaved homogeneous view. | |
100 | template <typename HomogeneousView> | |
101 | typename detail::channel_pointer_type<HomogeneousView>::type interleaved_view_get_raw_data(const HomogeneousView& view) { | |
102 | BOOST_STATIC_ASSERT((!is_planar<HomogeneousView>::value && view_is_basic<HomogeneousView>::value)); | |
103 | BOOST_STATIC_ASSERT((boost::is_pointer<typename HomogeneousView::x_iterator>::value)); | |
104 | ||
105 | return &gil::at_c<0>(view(0,0)); | |
106 | } | |
107 | ||
108 | /// \ingroup ImageViewConstructors | |
109 | /// \brief Returns C pointer to the the channels of a given color plane of a planar homogeneous view. | |
110 | template <typename HomogeneousView> | |
111 | typename detail::channel_pointer_type<HomogeneousView>::type planar_view_get_raw_data(const HomogeneousView& view, int plane_index) { | |
112 | BOOST_STATIC_ASSERT((is_planar<HomogeneousView>::value && view_is_basic<HomogeneousView>::value)); | |
113 | return dynamic_at_c(view.row_begin(0),plane_index); | |
114 | } | |
115 | ||
116 | ||
117 | /// \defgroup ImageViewTransformationsColorConvert color_converted_view | |
118 | /// \ingroup ImageViewTransformations | |
119 | /// \brief Color converted view of another view | |
120 | ||
121 | /// \ingroup ImageViewTransformationsColorConvert PixelDereferenceAdaptorModel | |
122 | /// \brief Function object that given a source pixel, returns it converted to a given color space and channel depth. Models: PixelDereferenceAdaptorConcept | |
123 | /// | |
124 | /// Useful in constructing a color converted view over a given image view | |
125 | template <typename SrcConstRefP, typename DstP, typename CC=default_color_converter > // const_reference to the source pixel and destination pixel value | |
126 | class color_convert_deref_fn : public deref_base<color_convert_deref_fn<SrcConstRefP,DstP,CC>, DstP, DstP, const DstP&, SrcConstRefP, DstP, false> { | |
127 | private: | |
128 | CC _cc; // color-converter | |
129 | public: | |
130 | color_convert_deref_fn() {} | |
131 | color_convert_deref_fn(CC cc_in) : _cc(cc_in) {} | |
132 | ||
133 | DstP operator()(SrcConstRefP srcP) const { | |
134 | DstP dstP; | |
135 | _cc(srcP,dstP); | |
136 | return dstP; | |
137 | } | |
138 | }; | |
139 | ||
140 | namespace detail { | |
141 | // Add color converter upon dereferencing | |
142 | template <typename SrcView, typename CC, typename DstP, typename SrcP> | |
143 | struct _color_converted_view_type { | |
144 | private: | |
145 | typedef color_convert_deref_fn<typename SrcView::const_t::reference,DstP,CC> deref_t; | |
146 | typedef typename SrcView::template add_deref<deref_t> add_ref_t; | |
147 | public: | |
148 | typedef typename add_ref_t::type type; | |
149 | static type make(const SrcView& sv,CC cc) {return add_ref_t::make(sv,deref_t(cc));} | |
150 | }; | |
151 | ||
152 | // If the Src view has the same pixel type as the target, there is no need for color conversion | |
153 | template <typename SrcView, typename CC, typename DstP> | |
154 | struct _color_converted_view_type<SrcView,CC,DstP,DstP> { | |
155 | typedef SrcView type; | |
156 | static type make(const SrcView& sv,CC) {return sv;} | |
157 | }; | |
158 | } // namespace detail | |
159 | ||
160 | ||
161 | /// \brief Returns the type of a view that does color conversion upon dereferencing its pixels | |
162 | /// \ingroup ImageViewTransformationsColorConvert | |
163 | template <typename SrcView, typename DstP, typename CC=default_color_converter> | |
164 | struct color_converted_view_type : public detail::_color_converted_view_type<SrcView, | |
165 | CC, | |
166 | DstP, | |
167 | typename SrcView::value_type> { | |
168 | GIL_CLASS_REQUIRE(DstP, boost::gil, MutablePixelConcept)//why does it have to be mutable??? | |
169 | }; | |
170 | ||
171 | ||
172 | /// \ingroup ImageViewTransformationsColorConvert | |
173 | /// \brief view of a different color space with a user defined color-converter | |
174 | template <typename DstP, typename View, typename CC> | |
175 | inline typename color_converted_view_type<View,DstP,CC>::type color_converted_view(const View& src,CC cc) { | |
176 | return color_converted_view_type<View,DstP,CC>::make(src,cc); | |
177 | } | |
178 | ||
179 | /// \ingroup ImageViewTransformationsColorConvert | |
180 | /// \brief overload of generic color_converted_view with the default color-converter | |
181 | template <typename DstP, typename View> | |
182 | inline typename color_converted_view_type<View,DstP>::type | |
183 | color_converted_view(const View& src) { | |
184 | return color_converted_view<DstP>(src,default_color_converter()); | |
185 | } | |
186 | ||
187 | /// \defgroup ImageViewTransformationsFlipUD flipped_up_down_view | |
188 | /// \ingroup ImageViewTransformations | |
189 | /// \brief view of a view flipped up-to-down | |
190 | ||
191 | /// \ingroup ImageViewTransformationsFlipUD | |
192 | template <typename View> | |
193 | inline typename dynamic_y_step_type<View>::type flipped_up_down_view(const View& src) { | |
194 | typedef typename dynamic_y_step_type<View>::type RView; | |
195 | return RView(src.dimensions(),typename RView::xy_locator(src.xy_at(0,src.height()-1),-1)); | |
196 | } | |
197 | ||
198 | /// \defgroup ImageViewTransformationsFlipLR flipped_left_right_view | |
199 | /// \ingroup ImageViewTransformations | |
200 | /// \brief view of a view flipped left-to-right | |
201 | ||
202 | /// \ingroup ImageViewTransformationsFlipLR | |
203 | template <typename View> | |
204 | inline typename dynamic_x_step_type<View>::type flipped_left_right_view(const View& src) { | |
205 | typedef typename dynamic_x_step_type<View>::type RView; | |
206 | return RView(src.dimensions(),typename RView::xy_locator(src.xy_at(src.width()-1,0),-1,1)); | |
207 | } | |
208 | ||
209 | /// \defgroup ImageViewTransformationsTransposed transposed_view | |
210 | /// \ingroup ImageViewTransformations | |
211 | /// \brief view of a view transposed | |
212 | ||
213 | /// \ingroup ImageViewTransformationsTransposed | |
214 | template <typename View> | |
215 | inline typename dynamic_xy_step_transposed_type<View>::type transposed_view(const View& src) { | |
216 | typedef typename dynamic_xy_step_transposed_type<View>::type RView; | |
217 | return RView(src.height(),src.width(),typename RView::xy_locator(src.xy_at(0,0),1,1,true)); | |
218 | } | |
219 | ||
220 | /// \defgroup ImageViewTransformations90CW rotated90cw_view | |
221 | /// \ingroup ImageViewTransformations | |
222 | /// \brief view of a view rotated 90 degrees clockwise | |
223 | ||
224 | /// \ingroup ImageViewTransformations90CW | |
225 | template <typename View> | |
226 | inline typename dynamic_xy_step_transposed_type<View>::type rotated90cw_view(const View& src) { | |
227 | typedef typename dynamic_xy_step_transposed_type<View>::type RView; | |
228 | return RView(src.height(),src.width(),typename RView::xy_locator(src.xy_at(0,src.height()-1),-1,1,true)); | |
229 | } | |
230 | ||
231 | /// \defgroup ImageViewTransformations90CCW rotated90ccw_view | |
232 | /// \ingroup ImageViewTransformations | |
233 | /// \brief view of a view rotated 90 degrees counter-clockwise | |
234 | ||
235 | /// \ingroup ImageViewTransformations90CCW | |
236 | template <typename View> | |
237 | inline typename dynamic_xy_step_transposed_type<View>::type rotated90ccw_view(const View& src) { | |
238 | typedef typename dynamic_xy_step_transposed_type<View>::type RView; | |
239 | return RView(src.height(),src.width(),typename RView::xy_locator(src.xy_at(src.width()-1,0),1,-1,true)); | |
240 | } | |
241 | ||
242 | /// \defgroup ImageViewTransformations180 rotated180_view | |
243 | /// \ingroup ImageViewTransformations | |
244 | /// \brief view of a view rotated 180 degrees | |
245 | ||
246 | /// \ingroup ImageViewTransformations180 | |
247 | template <typename View> | |
248 | inline typename dynamic_xy_step_type<View>::type rotated180_view(const View& src) { | |
249 | typedef typename dynamic_xy_step_type<View>::type RView; | |
250 | return RView(src.dimensions(),typename RView::xy_locator(src.xy_at(src.width()-1,src.height()-1),-1,-1)); | |
251 | } | |
252 | ||
253 | /// \defgroup ImageViewTransformationsSubimage subimage_view | |
254 | /// \ingroup ImageViewTransformations | |
255 | /// \brief view of an axis-aligned rectangular area within an image_view | |
256 | ||
257 | /// \ingroup ImageViewTransformationsSubimage | |
258 | template <typename View> | |
259 | inline View subimage_view(const View& src, const typename View::point_t& topleft, const typename View::point_t& dimensions) { | |
260 | return View(dimensions,src.xy_at(topleft)); | |
261 | } | |
262 | ||
263 | /// \ingroup ImageViewTransformationsSubimage | |
264 | template <typename View> | |
265 | inline View subimage_view(const View& src, int xMin, int yMin, int width, int height) { | |
266 | return View(width,height,src.xy_at(xMin,yMin)); | |
267 | } | |
268 | ||
269 | /// \defgroup ImageViewTransformationsSubsampled subsampled_view | |
270 | /// \ingroup ImageViewTransformations | |
271 | /// \brief view of a subsampled version of an image_view, stepping over a number of channels in X and number of rows in Y | |
272 | ||
273 | /// \ingroup ImageViewTransformationsSubsampled | |
274 | template <typename View> | |
275 | inline typename dynamic_xy_step_type<View>::type subsampled_view(const View& src, typename View::coord_t xStep, typename View::coord_t yStep) { | |
276 | assert(xStep>0 && yStep>0); | |
277 | typedef typename dynamic_xy_step_type<View>::type RView; | |
278 | return RView((src.width()+(xStep-1))/xStep,(src.height()+(yStep-1))/yStep, | |
279 | typename RView::xy_locator(src.xy_at(0,0),xStep,yStep)); | |
280 | } | |
281 | ||
282 | /// \ingroup ImageViewTransformationsSubsampled | |
283 | template <typename View> | |
284 | inline typename dynamic_xy_step_type<View>::type subsampled_view(const View& src, const typename View::point_t& step) { | |
285 | return subsampled_view(src,step.x,step.y); | |
286 | } | |
287 | ||
288 | /// \defgroup ImageViewTransformationsNthChannel nth_channel_view | |
289 | /// \ingroup ImageViewTransformations | |
290 | /// \brief single-channel (grayscale) view of the N-th channel of a given image_view | |
291 | ||
292 | namespace detail { | |
293 | template <typename View, bool AreChannelsTogether> struct __nth_channel_view_basic; | |
294 | ||
295 | // nth_channel_view when the channels are not adjacent in memory. This can happen for multi-channel interleaved images | |
296 | // or images with a step | |
297 | template <typename View> | |
298 | struct __nth_channel_view_basic<View,false> { | |
299 | typedef typename view_type<typename channel_type<View>::type, gray_layout_t, false, true, view_is_mutable<View>::value>::type type; | |
300 | ||
301 | static type make(const View& src, int n) { | |
302 | typedef typename type::xy_locator locator_t; | |
303 | typedef typename type::x_iterator x_iterator_t; | |
304 | typedef typename iterator_adaptor_get_base<x_iterator_t>::type x_iterator_base_t; | |
305 | x_iterator_t sit(x_iterator_base_t(&(src(0,0)[n])),src.pixels().pixel_size()); | |
306 | return type(src.dimensions(),locator_t(sit, src.pixels().row_size())); | |
307 | } | |
308 | }; | |
309 | ||
310 | // nth_channel_view when the channels are together in memory (true for simple grayscale or planar images) | |
311 | template <typename View> | |
312 | struct __nth_channel_view_basic<View,true> { | |
313 | typedef typename view_type<typename channel_type<View>::type, gray_layout_t, false, false, view_is_mutable<View>::value>::type type; | |
314 | static type make(const View& src, int n) { | |
315 | typedef typename type::x_iterator x_iterator_t; | |
316 | return interleaved_view(src.width(),src.height(),(x_iterator_t)&(src(0,0)[n]), src.pixels().row_size()); | |
317 | } | |
318 | }; | |
319 | ||
320 | template <typename View, bool IsBasic> struct __nth_channel_view; | |
321 | ||
322 | // For basic (memory-based) views dispatch to __nth_channel_view_basic | |
323 | template <typename View> struct __nth_channel_view<View,true> { | |
324 | private: | |
325 | typedef typename View::x_iterator src_x_iterator; | |
326 | ||
327 | // Determines whether the channels of a given pixel iterator are adjacent in memory. | |
328 | // Planar and grayscale iterators have channels adjacent in memory, whereas multi-channel interleaved and iterators with non-fundamental step do not. | |
329 | BOOST_STATIC_CONSTANT(bool, adjacent= | |
330 | !iterator_is_step<src_x_iterator>::value && | |
331 | (is_planar<src_x_iterator>::value || | |
332 | num_channels<View>::value==1)); | |
333 | public: | |
334 | typedef typename __nth_channel_view_basic<View,adjacent>::type type; | |
335 | ||
336 | static type make(const View& src, int n) { | |
337 | return __nth_channel_view_basic<View,adjacent>::make(src,n); | |
338 | } | |
339 | }; | |
340 | ||
341 | /// \brief Function object that returns a grayscale reference of the N-th channel of a given reference. Models: PixelDereferenceAdaptorConcept. | |
342 | /// \ingroup PixelDereferenceAdaptorModel | |
343 | /// | |
344 | /// If the input is a pixel value or constant reference, the function object is immutable. Otherwise it is mutable (and returns non-const reference to the n-th channel) | |
345 | template <typename SrcP> // SrcP is a reference to PixelConcept (could be pixel value or const/non-const reference) | |
346 | // Examples: pixel<T,L>, pixel<T,L>&, const pixel<T,L>&, planar_pixel_reference<T&,L>, planar_pixel_reference<const T&,L> | |
347 | struct nth_channel_deref_fn { | |
348 | BOOST_STATIC_CONSTANT(bool, is_mutable=pixel_is_reference<SrcP>::value && pixel_reference_is_mutable<SrcP>::value); | |
349 | private: | |
350 | typedef typename remove_reference<SrcP>::type src_pixel_t; | |
351 | typedef typename channel_type<src_pixel_t>::type channel_t; | |
352 | typedef typename src_pixel_t::const_reference const_ref_t; | |
353 | typedef typename pixel_reference_type<channel_t,gray_layout_t,false,is_mutable>::type ref_t; | |
354 | public: | |
355 | typedef nth_channel_deref_fn<const_ref_t> const_t; | |
356 | typedef typename pixel_value_type<channel_t,gray_layout_t>::type value_type; | |
357 | typedef typename pixel_reference_type<channel_t,gray_layout_t,false,false>::type const_reference; | |
358 | typedef SrcP argument_type; | |
359 | typedef typename mpl::if_c<is_mutable, ref_t, value_type>::type reference; | |
360 | typedef reference result_type; | |
361 | ||
362 | nth_channel_deref_fn(int n=0) : _n(n) {} | |
363 | template <typename P> nth_channel_deref_fn(const nth_channel_deref_fn<P>& d) : _n(d._n) {} | |
364 | ||
365 | int _n; // the channel to use | |
366 | ||
367 | result_type operator()(argument_type srcP) const { | |
368 | return result_type(srcP[_n]); | |
369 | } | |
370 | }; | |
371 | ||
372 | template <typename View> struct __nth_channel_view<View,false> { | |
373 | private: | |
374 | typedef nth_channel_deref_fn<typename View::reference> deref_t; | |
375 | typedef typename View::template add_deref<deref_t> AD; | |
376 | public: | |
377 | typedef typename AD::type type; | |
378 | static type make(const View& src, int n) { | |
379 | return AD::make(src, deref_t(n)); | |
380 | } | |
381 | }; | |
382 | } // namespace detail | |
383 | ||
384 | /// \brief Given a source image view type View, returns the type of an image view over a single channel of View | |
385 | /// \ingroup ImageViewTransformationsNthChannel | |
386 | /// | |
387 | /// If the channels in the source view are adjacent in memory (such as planar non-step view or single-channel view) then the | |
388 | /// return view is a single-channel non-step view. | |
389 | /// If the channels are non-adjacent (interleaved and/or step view) then the return view is a single-channel step view. | |
390 | template <typename View> | |
391 | struct nth_channel_view_type { | |
392 | private: | |
393 | GIL_CLASS_REQUIRE(View, boost::gil, ImageViewConcept) | |
394 | typedef detail::__nth_channel_view<View,view_is_basic<View>::value> VB; | |
395 | public: | |
396 | typedef typename VB::type type; | |
397 | static type make(const View& src, int n) { return VB::make(src,n); } | |
398 | }; | |
399 | ||
400 | ||
401 | /// \ingroup ImageViewTransformationsNthChannel | |
402 | template <typename View> | |
403 | typename nth_channel_view_type<View>::type nth_channel_view(const View& src, int n) { | |
404 | return nth_channel_view_type<View>::make(src,n); | |
405 | } | |
406 | ||
407 | ||
408 | ||
409 | ||
410 | ||
411 | ||
412 | ||
413 | /// \defgroup ImageViewTransformationsKthChannel kth_channel_view | |
414 | /// \ingroup ImageViewTransformations | |
415 | /// \brief single-channel (grayscale) view of the K-th channel of a given image_view. The channel index is a template parameter | |
416 | ||
417 | namespace detail { | |
418 | template <int K, typename View, bool AreChannelsTogether> struct __kth_channel_view_basic; | |
419 | ||
420 | // kth_channel_view when the channels are not adjacent in memory. This can happen for multi-channel interleaved images | |
421 | // or images with a step | |
422 | template <int K, typename View> | |
423 | struct __kth_channel_view_basic<K,View,false> { | |
424 | private: | |
425 | typedef typename kth_element_type<typename View::value_type,K>::type channel_t; | |
426 | public: | |
427 | typedef typename view_type<channel_t, gray_layout_t, false, true, view_is_mutable<View>::value>::type type; | |
428 | ||
429 | static type make(const View& src) { | |
430 | typedef typename type::xy_locator locator_t; | |
431 | typedef typename type::x_iterator x_iterator_t; | |
432 | typedef typename iterator_adaptor_get_base<x_iterator_t>::type x_iterator_base_t; | |
433 | x_iterator_t sit(x_iterator_base_t(&gil::at_c<K>(src(0,0))),src.pixels().pixel_size()); | |
434 | return type(src.dimensions(),locator_t(sit, src.pixels().row_size())); | |
435 | } | |
436 | }; | |
437 | ||
438 | // kth_channel_view when the channels are together in memory (true for simple grayscale or planar images) | |
439 | template <int K, typename View> | |
440 | struct __kth_channel_view_basic<K,View,true> { | |
441 | private: | |
442 | typedef typename kth_element_type<typename View::value_type, K>::type channel_t; | |
443 | public: | |
444 | typedef typename view_type<channel_t, gray_layout_t, false, false, view_is_mutable<View>::value>::type type; | |
445 | static type make(const View& src) { | |
446 | typedef typename type::x_iterator x_iterator_t; | |
447 | return interleaved_view(src.width(),src.height(),(x_iterator_t)&gil::at_c<K>(src(0,0)), src.pixels().row_size()); | |
448 | } | |
449 | }; | |
450 | ||
451 | template <int K, typename View, bool IsBasic> struct __kth_channel_view; | |
452 | ||
453 | // For basic (memory-based) views dispatch to __kth_channel_view_basic | |
454 | template <int K, typename View> struct __kth_channel_view<K,View,true> { | |
455 | private: | |
456 | typedef typename View::x_iterator src_x_iterator; | |
457 | ||
458 | // Determines whether the channels of a given pixel iterator are adjacent in memory. | |
459 | // Planar and grayscale iterators have channels adjacent in memory, whereas multi-channel interleaved and iterators with non-fundamental step do not. | |
460 | BOOST_STATIC_CONSTANT(bool, adjacent= | |
461 | !iterator_is_step<src_x_iterator>::value && | |
462 | (is_planar<src_x_iterator>::value || | |
463 | num_channels<View>::value==1)); | |
464 | public: | |
465 | typedef typename __kth_channel_view_basic<K,View,adjacent>::type type; | |
466 | ||
467 | static type make(const View& src) { | |
468 | return __kth_channel_view_basic<K,View,adjacent>::make(src); | |
469 | } | |
470 | }; | |
471 | ||
472 | /// \brief Function object that returns a grayscale reference of the K-th channel (specified as a template parameter) of a given reference. Models: PixelDereferenceAdaptorConcept. | |
473 | /// \ingroup PixelDereferenceAdaptorModel | |
474 | /// | |
475 | /// If the input is a pixel value or constant reference, the function object is immutable. Otherwise it is mutable (and returns non-const reference to the k-th channel) | |
476 | template <int K, typename SrcP> // SrcP is a reference to PixelConcept (could be pixel value or const/non-const reference) | |
477 | // Examples: pixel<T,L>, pixel<T,L>&, const pixel<T,L>&, planar_pixel_reference<T&,L>, planar_pixel_reference<const T&,L> | |
478 | struct kth_channel_deref_fn { | |
479 | BOOST_STATIC_CONSTANT(bool, is_mutable=pixel_is_reference<SrcP>::value && pixel_reference_is_mutable<SrcP>::value); | |
480 | private: | |
481 | typedef typename remove_reference<SrcP>::type src_pixel_t; | |
482 | typedef typename kth_element_type<src_pixel_t, K>::type channel_t; | |
483 | typedef typename src_pixel_t::const_reference const_ref_t; | |
484 | typedef typename pixel_reference_type<channel_t,gray_layout_t,false,is_mutable>::type ref_t; | |
485 | public: | |
486 | typedef kth_channel_deref_fn<K,const_ref_t> const_t; | |
487 | typedef typename pixel_value_type<channel_t,gray_layout_t>::type value_type; | |
488 | typedef typename pixel_reference_type<channel_t,gray_layout_t,false,false>::type const_reference; | |
489 | typedef SrcP argument_type; | |
490 | typedef typename mpl::if_c<is_mutable, ref_t, value_type>::type reference; | |
491 | typedef reference result_type; | |
492 | ||
493 | kth_channel_deref_fn() {} | |
494 | template <typename P> kth_channel_deref_fn(const kth_channel_deref_fn<K,P>&) {} | |
495 | ||
496 | result_type operator()(argument_type srcP) const { | |
497 | return result_type(gil::at_c<K>(srcP)); | |
498 | } | |
499 | }; | |
500 | ||
501 | template <int K, typename View> struct __kth_channel_view<K,View,false> { | |
502 | private: | |
503 | typedef kth_channel_deref_fn<K,typename View::reference> deref_t; | |
504 | typedef typename View::template add_deref<deref_t> AD; | |
505 | public: | |
506 | typedef typename AD::type type; | |
507 | static type make(const View& src) { | |
508 | return AD::make(src, deref_t()); | |
509 | } | |
510 | }; | |
511 | } // namespace detail | |
512 | ||
513 | /// \brief Given a source image view type View, returns the type of an image view over a given channel of View. | |
514 | /// \ingroup ImageViewTransformationsKthChannel | |
515 | /// | |
516 | /// If the channels in the source view are adjacent in memory (such as planar non-step view or single-channel view) then the | |
517 | /// return view is a single-channel non-step view. | |
518 | /// If the channels are non-adjacent (interleaved and/or step view) then the return view is a single-channel step view. | |
519 | template <int K, typename View> | |
520 | struct kth_channel_view_type { | |
521 | private: | |
522 | GIL_CLASS_REQUIRE(View, boost::gil, ImageViewConcept) | |
523 | typedef detail::__kth_channel_view<K,View,view_is_basic<View>::value> VB; | |
524 | public: | |
525 | typedef typename VB::type type; | |
526 | static type make(const View& src) { return VB::make(src); } | |
527 | }; | |
528 | ||
529 | /// \ingroup ImageViewTransformationsKthChannel | |
530 | template <int K, typename View> | |
531 | typename kth_channel_view_type<K,View>::type kth_channel_view(const View& src) { | |
532 | return kth_channel_view_type<K,View>::make(src); | |
533 | } | |
534 | ||
535 | } } // namespace boost::gil | |
536 | ||
537 | #endif |