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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_PIXEL_ITERATOR_H | |
14 | #define GIL_PIXEL_ITERATOR_H | |
15 | ||
16 | //////////////////////////////////////////////////////////////////////////////////////// | |
17 | /// \file | |
18 | /// \brief pixel iterator support | |
19 | /// \author Lubomir Bourdev and Hailin Jin \n | |
20 | /// Adobe Systems Incorporated | |
21 | /// \date 2005-2007 \n May 16, 2006 | |
22 | /// | |
23 | //////////////////////////////////////////////////////////////////////////////////////// | |
24 | ||
25 | #include <cassert> | |
26 | #include <iterator> | |
27 | #include "gil_config.hpp" | |
28 | #include "gil_concept.hpp" | |
29 | #include "utilities.hpp" | |
30 | #include "pixel.hpp" | |
31 | ||
32 | namespace boost { namespace gil { | |
33 | ||
34 | //forwarded declaration (as this file is included in step_iterator.hpp) | |
35 | template <typename Iterator> | |
36 | class memory_based_step_iterator; | |
37 | ||
38 | template <typename Iterator> struct dynamic_x_step_type; | |
39 | ||
40 | /// \brief metafunction predicate determining whether the given iterator is a plain one or an adaptor over another iterator. | |
41 | /// Examples of adaptors are the step iterator and the dereference iterator adaptor. | |
42 | template <typename It> | |
43 | struct is_iterator_adaptor : public mpl::false_{}; | |
44 | ||
45 | /// \brief returns the base iterator for a given iterator adaptor. Provide an specialization when introducing new iterator adaptors | |
46 | template <typename It> | |
47 | struct iterator_adaptor_get_base; | |
48 | ||
49 | /// \brief Changes the base iterator of an iterator adaptor. Provide an specialization when introducing new iterator adaptors | |
50 | template <typename It, typename NewBaseIt> | |
51 | struct iterator_adaptor_rebind; | |
52 | ||
53 | /// \brief Returns the type of an iterator just like the input iterator, except operating over immutable values | |
54 | template <typename It> | |
55 | struct const_iterator_type; | |
56 | ||
57 | // The default implementation when the iterator is a C pointer is to use the standard constness semantics | |
58 | template <typename T> struct const_iterator_type< T*> { typedef const T* type; }; | |
59 | template <typename T> struct const_iterator_type<const T*> { typedef const T* type; }; | |
60 | ||
61 | /// \brief Metafunction predicate returning whether the given iterator allows for changing its values | |
62 | /// \ingroup GILIsMutable | |
63 | template <typename It> | |
64 | struct iterator_is_mutable{}; | |
65 | ||
66 | // The default implementation when the iterator is a C pointer is to use the standard constness semantics | |
67 | template <typename T> struct iterator_is_mutable< T*> : public mpl::true_{}; | |
68 | template <typename T> struct iterator_is_mutable<const T*> : public mpl::false_{}; | |
69 | ||
70 | /// \defgroup PixelIteratorModelInterleavedPtr C pointer to a pixel | |
71 | /// \ingroup PixelIteratorModel | |
72 | /// \brief Iterators over interleaved pixels. | |
73 | /// A C pointer to a model of PixelValueConcept is used as an iterator over interleaved pixels. Models PixelIteratorConcept, HomogeneousPixelBasedConcept, HasDynamicXStepTypeConcept, MemoryBasedIteratorConcept | |
74 | ||
75 | ||
76 | ||
77 | ///////////////////////////// | |
78 | // HasDynamicXStepTypeConcept | |
79 | ///////////////////////////// | |
80 | ||
81 | /// \ingroup PixelIteratorModelInterleavedPtr | |
82 | template <typename Pixel> | |
83 | struct dynamic_x_step_type<Pixel*> { | |
84 | typedef memory_based_step_iterator<Pixel*> type; | |
85 | }; | |
86 | ||
87 | /// \ingroup PixelIteratorModelInterleavedPtr | |
88 | template <typename Pixel> | |
89 | struct dynamic_x_step_type<const Pixel*> { | |
90 | typedef memory_based_step_iterator<const Pixel*> type; | |
91 | }; | |
92 | ||
93 | ||
94 | ///////////////////////////// | |
95 | // PixelBasedConcept | |
96 | ///////////////////////////// | |
97 | ||
98 | template <typename Pixel> struct color_space_type< Pixel*> : public color_space_type<Pixel> {}; | |
99 | template <typename Pixel> struct color_space_type<const Pixel*> : public color_space_type<Pixel> {}; | |
100 | ||
101 | template <typename Pixel> struct channel_mapping_type< Pixel*> : public channel_mapping_type<Pixel> {}; | |
102 | template <typename Pixel> struct channel_mapping_type<const Pixel*> : public channel_mapping_type<Pixel> {}; | |
103 | ||
104 | template <typename Pixel> struct is_planar< Pixel*> : public is_planar<Pixel> {}; | |
105 | template <typename Pixel> struct is_planar<const Pixel*> : public is_planar<Pixel> {}; | |
106 | ||
107 | ///////////////////////////// | |
108 | // HomogeneousPixelBasedConcept | |
109 | ///////////////////////////// | |
110 | ||
111 | template <typename Pixel> struct channel_type<Pixel*> : public channel_type<Pixel> {}; | |
112 | template <typename Pixel> struct channel_type<const Pixel*> : public channel_type<Pixel> {}; | |
113 | ||
114 | //////////////////////////////////////////////////////////////////////////////////////// | |
115 | /// | |
116 | /// Support for pixel iterator movement measured in memory units (bytes or bits) as opposed to pixel type. \n | |
117 | /// Necessary to handle image row alignment and channel plane alignment. | |
118 | /// | |
119 | //////////////////////////////////////////////////////////////////////////////////////// | |
120 | ||
121 | ///////////////////////////// | |
122 | // MemoryBasedIteratorConcept | |
123 | ///////////////////////////// | |
124 | ||
125 | template <typename T> | |
126 | struct byte_to_memunit : public mpl::int_<1> {}; | |
127 | ||
128 | template <typename P> | |
129 | inline std::ptrdiff_t memunit_step(const P*) { return sizeof(P); } | |
130 | ||
131 | template <typename P> | |
132 | inline std::ptrdiff_t memunit_distance(const P* p1, const P* p2) { | |
133 | return (gil_reinterpret_cast_c<const unsigned char*>(p2)-gil_reinterpret_cast_c<const unsigned char*>(p1)); | |
134 | } | |
135 | ||
136 | template <typename P> | |
137 | inline void memunit_advance(P* &p, std::ptrdiff_t diff) { | |
138 | p=(P*)((unsigned char*)(p)+diff); | |
139 | } | |
140 | ||
141 | template <typename P> | |
142 | inline P* memunit_advanced(const P* p, std::ptrdiff_t diff) { | |
143 | return (P*)((char*)(p)+diff); | |
144 | } | |
145 | ||
146 | // memunit_advanced_ref | |
147 | // (shortcut to advancing a pointer by a given number of memunits and taking the reference in case the compiler is not smart enough) | |
148 | ||
149 | template <typename P> | |
150 | inline P& memunit_advanced_ref(P* p, std::ptrdiff_t diff) { | |
151 | return *memunit_advanced(p,diff); | |
152 | } | |
153 | ||
154 | } } // namespace boost::gil | |
155 | ||
156 | #endif |