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_PACKED_PIXEL_HPP
9 #define BOOST_GIL_PACKED_PIXEL_HPP
10
11 #include <boost/gil/pixel.hpp>
12 #include <boost/gil/detail/mp11.hpp>
13
14 #include <functional>
15 #include <type_traits>
16
17 namespace boost { namespace gil {
18
19 /// A model of a heterogeneous pixel whose channels are bit ranges.
20 /// For example 16-bit RGB in '565' format.
21
22 /// \defgroup ColorBaseModelPackedPixel packed_pixel
23 /// \ingroup ColorBaseModel
24 /// \brief A heterogeneous color base whose elements are reference proxies to channels in a pixel. Models ColorBaseValueConcept. This class is used to model packed pixels, such as 16-bit packed RGB.
25
26 /// \defgroup PixelModelPackedPixel packed_pixel
27 /// \ingroup PixelModel
28 /// \brief A heterogeneous pixel used to represent packed pixels with non-byte-aligned channels. Models PixelValueConcept
29 ///
30 /// Example:
31 /// \code
32 /// using rgb565_pixel_t = packed_pixel_type<uint16_t, mp11::mp_list-c<unsigned,5,6,5>, rgb_layout_t>::type;
33 /// static_assert(sizeof(rgb565_pixel_t) == 2, "");
34 ///
35 /// rgb565_pixel_t r565;
36 /// get_color(r565,red_t()) = 31;
37 /// get_color(r565,green_t()) = 63;
38 /// get_color(r565,blue_t()) = 31;
39 /// assert(r565 == rgb565_pixel_t((uint16_t)0xFFFF));
40 /// \endcode
41
42 /// \ingroup ColorBaseModelPackedPixel PixelModelPackedPixel PixelBasedModel
43 /// \brief Heterogeneous pixel value whose channel references can be constructed from the pixel bitfield and their index. Models ColorBaseValueConcept, PixelValueConcept, PixelBasedConcept
44 /// Typical use for this is a model of a packed pixel (like 565 RGB)
45 /// \tparam BitField Type that holds the bits of the pixel. Typically an integral type, like std::uint16_t.
46 /// \tparam ChannelRefs MP11 list whose elements are packed channels. They must be constructible from BitField. GIL uses packed_channel_reference
47 /// \tparam Layout defining the color space and ordering of the channels. Example value: rgb_layout_t
48 template <typename BitField, typename ChannelRefs, typename Layout>
49 struct packed_pixel
50 {
51 BitField _bitfield{0}; // TODO: Make private
52
53 using layout_t = Layout;
54 using value_type = packed_pixel<BitField, ChannelRefs, Layout>;
55 using reference = value_type&;
56 using const_reference = value_type const&;
57
58 static constexpr bool is_mutable =
59 channel_traits<mp11::mp_front<ChannelRefs>>::is_mutable;
60
61 packed_pixel() = default;
packed_pixelboost::gil::packed_pixel62 explicit packed_pixel(const BitField& bitfield) : _bitfield(bitfield) {}
63
64 // Construct from another compatible pixel type
packed_pixelboost::gil::packed_pixel65 packed_pixel(const packed_pixel& p) : _bitfield(p._bitfield) {}
66
67 template <typename Pixel>
packed_pixelboost::gil::packed_pixel68 packed_pixel(Pixel const& p,
69 typename std::enable_if<is_pixel<Pixel>::value>::type* /*dummy*/ = nullptr)
70 {
71 check_compatible<Pixel>();
72 static_copy(p, *this);
73 }
74
packed_pixelboost::gil::packed_pixel75 packed_pixel(int chan0, int chan1)
76 : _bitfield(0)
77 {
78 static_assert(num_channels<packed_pixel>::value == 2, "");
79 gil::at_c<0>(*this) = chan0;
80 gil::at_c<1>(*this) = chan1;
81 }
82
packed_pixelboost::gil::packed_pixel83 packed_pixel(int chan0, int chan1, int chan2)
84 : _bitfield(0)
85 {
86 static_assert(num_channels<packed_pixel>::value == 3, "");
87 gil::at_c<0>(*this) = chan0;
88 gil::at_c<1>(*this) = chan1;
89 gil::at_c<2>(*this) = chan2;
90 }
91
packed_pixelboost::gil::packed_pixel92 packed_pixel(int chan0, int chan1, int chan2, int chan3)
93 : _bitfield(0)
94 {
95 static_assert(num_channels<packed_pixel>::value == 4, "");
96 gil::at_c<0>(*this) = chan0;
97 gil::at_c<1>(*this) = chan1;
98 gil::at_c<2>(*this) = chan2;
99 gil::at_c<3>(*this) = chan3;
100 }
101
packed_pixelboost::gil::packed_pixel102 packed_pixel(int chan0, int chan1, int chan2, int chan3, int chan4)
103 : _bitfield(0)
104 {
105 static_assert(num_channels<packed_pixel>::value == 5, "");
106 gil::at_c<0>(*this) = chan0;
107 gil::at_c<1>(*this) = chan1;
108 gil::at_c<2>(*this) = chan2;
109 gil::at_c<3>(*this) = chan3;
110 gil::at_c<4>(*this) = chan4;
111 }
112
operator =boost::gil::packed_pixel113 auto operator=(packed_pixel const& p) -> packed_pixel&
114 {
115 _bitfield = p._bitfield;
116 return *this;
117 }
118
119 template <typename Pixel>
operator =boost::gil::packed_pixel120 auto operator=(Pixel const& p) -> packed_pixel&
121 {
122 assign(p, is_pixel<Pixel>());
123 return *this;
124 }
125
126 template <typename Pixel>
operator ==boost::gil::packed_pixel127 bool operator==(Pixel const& p) const
128 {
129 return equal(p, is_pixel<Pixel>());
130 }
131
132 template <typename Pixel>
operator !=boost::gil::packed_pixel133 bool operator!=(Pixel const& p) const { return !(*this==p); }
134
135 private:
136 template <typename Pixel>
check_compatibleboost::gil::packed_pixel137 static void check_compatible()
138 {
139 gil_function_requires<PixelsCompatibleConcept<Pixel, packed_pixel>>();
140 }
141
142 template <typename Pixel>
assignboost::gil::packed_pixel143 void assign(Pixel const& p, std::true_type)
144 {
145 check_compatible<Pixel>();
146 static_copy(p, *this);
147 }
148
149 template <typename Pixel>
equalboost::gil::packed_pixel150 bool equal(Pixel const& p, std::true_type) const
151 {
152 check_compatible<Pixel>();
153 return static_equal(*this, p);
154 }
155
156 // Support for assignment/equality comparison of a channel with a grayscale pixel
check_grayboost::gil::packed_pixel157 static void check_gray()
158 {
159 static_assert(std::is_same<typename Layout::color_space_t, gray_t>::value, "");
160 }
161
162 template <typename Channel>
assignboost::gil::packed_pixel163 void assign(Channel const& channel, std::false_type)
164 {
165 check_gray();
166 gil::at_c<0>(*this) = channel;
167 }
168
169 template <typename Channel>
equalboost::gil::packed_pixel170 bool equal (Channel const& channel, std::false_type) const
171 {
172 check_gray();
173 return gil::at_c<0>(*this) == channel;
174 }
175
176 public:
operator =boost::gil::packed_pixel177 auto operator=(int channel) -> packed_pixel&
178 {
179 check_gray();
180 gil::at_c<0>(*this) = channel;
181 return *this;
182 }
183
operator ==boost::gil::packed_pixel184 bool operator==(int channel) const
185 {
186 check_gray();
187 return gil::at_c<0>(*this) == channel;
188 }
189 };
190
191 /////////////////////////////
192 // ColorBasedConcept
193 /////////////////////////////
194
195 template <typename BitField, typename ChannelRefs, typename Layout, int K>
196 struct kth_element_type<packed_pixel<BitField, ChannelRefs, Layout>, K>
197 {
198 using type = typename channel_traits<mp11::mp_at_c<ChannelRefs, K>>::value_type;
199 };
200
201 template <typename BitField, typename ChannelRefs, typename Layout, int K>
202 struct kth_element_reference_type<packed_pixel<BitField, ChannelRefs, Layout>, K>
203 {
204 using type = typename channel_traits<mp11::mp_at_c<ChannelRefs, K>>::reference;
205 };
206
207 template <typename BitField, typename ChannelRefs, typename Layout, int K>
208 struct kth_element_const_reference_type<packed_pixel<BitField, ChannelRefs, Layout>, K>
209 {
210 using type = typename channel_traits<mp11::mp_at_c<ChannelRefs, K>>::const_reference;
211 };
212
213 template <int K, typename P, typename C, typename L>
214 inline
at_c(packed_pixel<P,C,L> & p)215 auto at_c(packed_pixel<P, C, L>& p)
216 -> typename kth_element_reference_type<packed_pixel<P, C, L>, K>::type
217 {
218 return typename kth_element_reference_type
219 <
220 packed_pixel<P, C, L>,
221 K
222 >::type{&p._bitfield};
223 }
224
225 template <int K, typename P, typename C, typename L>
226 inline
at_c(const packed_pixel<P,C,L> & p)227 auto at_c(const packed_pixel<P, C, L>& p)
228 -> typename kth_element_const_reference_type<packed_pixel<P, C, L>, K>::type
229 {
230 return typename kth_element_const_reference_type
231 <
232 packed_pixel<P, C, L>,
233 K>::type{&p._bitfield};
234 }
235
236 /////////////////////////////
237 // PixelConcept
238 /////////////////////////////
239
240 // Metafunction predicate that flags packed_pixel as a model of PixelConcept.
241 // Required by PixelConcept
242 template <typename BitField, typename ChannelRefs, typename Layout>
243 struct is_pixel<packed_pixel<BitField, ChannelRefs, Layout>> : std::true_type {};
244
245 /////////////////////////////
246 // PixelBasedConcept
247 /////////////////////////////
248
249 template <typename P, typename C, typename Layout>
250 struct color_space_type<packed_pixel<P, C, Layout>>
251 {
252 using type = typename Layout::color_space_t;
253 };
254
255 template <typename P, typename C, typename Layout>
256 struct channel_mapping_type<packed_pixel<P, C, Layout>>
257 {
258 using type = typename Layout::channel_mapping_t;
259 };
260
261 template <typename P, typename C, typename Layout>
262 struct is_planar<packed_pixel<P, C, Layout>> : std::false_type {};
263
264 ////////////////////////////////////////////////////////////////////////////////
265 /// Support for interleaved iterators over packed pixel
266 ////////////////////////////////////////////////////////////////////////////////
267
268 /// \defgroup PixelIteratorModelPackedInterleavedPtr Pointer to packed_pixel<P,CR,Layout>
269 /// \ingroup PixelIteratorModel
270 /// \brief Iterators over interleaved pixels.
271 /// The pointer packed_pixel<P,CR,Layout>* is used as an iterator over interleaved
272 /// pixels of packed format.
273 /// Models PixelIteratorConcept, HasDynamicXStepTypeConcept, MemoryBasedIteratorConcept
274
275 template <typename P, typename C, typename L>
276 struct iterator_is_mutable<packed_pixel<P, C, L>*>
277 : std::integral_constant<bool, packed_pixel<P, C, L>::is_mutable>
278 {};
279
280 template <typename P, typename C, typename L>
281 struct iterator_is_mutable<const packed_pixel<P, C, L>*> : std::false_type {};
282
283 }} // namespace boost::gil
284
285 #endif
286