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_PACKED_PIXEL_H
14#define GIL_PACKED_PIXEL_H
15
16////////////////////////////////////////////////////////////////////////////////////////
17/// \file
18/// \brief A model of a heterogeneous pixel whose channels are bit ranges. For example 16-bit RGB in '565' format
19/// \author Lubomir Bourdev and Hailin Jin \n
20/// Adobe Systems Incorporated
21/// \date 2005-2009 \n Last updated on February 20, 2009
22///
23////////////////////////////////////////////////////////////////////////////////////////
24
25#include <functional>
26#include <boost/utility/enable_if.hpp>
27#include <boost/mpl/bool.hpp>
28#include <boost/mpl/front.hpp>
29#include "gil_config.hpp"
30#include "pixel.hpp"
31
32namespace boost { namespace gil {
33
34/// \defgroup ColorBaseModelPackedPixel packed_pixel
35/// \ingroup ColorBaseModel
36/// \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.
37
38/**
39\defgroup PixelModelPackedPixel packed_pixel
40\ingroup PixelModel
41\brief A heterogeneous pixel used to represent packed pixels with non-byte-aligned channels. Models PixelValueConcept
42
43Example:
44\code
45typedef packed_pixel_type<uint16_t, mpl::vector3_c<unsigned,5,6,5>, rgb_layout_t>::type rgb565_pixel_t;
46BOOST_STATIC_ASSERT((sizeof(rgb565_pixel_t)==2));
47
48rgb565_pixel_t r565;
49get_color(r565,red_t()) = 31;
50get_color(r565,green_t()) = 63;
51get_color(r565,blue_t()) = 31;
52assert(r565 == rgb565_pixel_t((uint16_t)0xFFFF));
53\endcode
54*/
55
56/// \ingroup ColorBaseModelPackedPixel PixelModelPackedPixel PixelBasedModel
57/// \brief Heterogeneous pixel value whose channel references can be constructed from the pixel bitfield and their index. Models ColorBaseValueConcept, PixelValueConcept, PixelBasedConcept
58/// Typical use for this is a model of a packed pixel (like 565 RGB)
59template <typename BitField, // A type that holds the bits of the pixel. Typically an integral type, like boost::uint16_t
60 typename ChannelRefVec, // An MPL vector whose elements are packed channels. They must be constructible from BitField. GIL uses packed_channel_reference
61 typename Layout> // Layout defining the color space and ordering of the channels. Example value: rgb_layout_t
62struct packed_pixel {
63 BitField _bitfield;
64
65 typedef Layout layout_t;
66 typedef packed_pixel value_type;
67 typedef value_type& reference;
68 typedef const value_type& const_reference;
69
70 BOOST_STATIC_CONSTANT(bool, is_mutable = channel_traits<typename mpl::front<ChannelRefVec>::type>::is_mutable);
71
72 packed_pixel(){}
73 explicit packed_pixel(const BitField& bitfield) : _bitfield(bitfield) {}
74
75 // Construct from another compatible pixel type
76 packed_pixel(const packed_pixel& p) : _bitfield(p._bitfield) {}
77 template <typename P> packed_pixel(const P& p, typename enable_if_c<is_pixel<P>::value>::type* d=0) { check_compatible<P>(); static_copy(p,*this); }
78 packed_pixel(int chan0, int chan1) : _bitfield(0) {
79 BOOST_STATIC_ASSERT((num_channels<packed_pixel>::value==2));
80 at_c<0>(*this)=chan0; at_c<1>(*this)=chan1;
81 }
82 packed_pixel(int chan0, int chan1, int chan2) : _bitfield(0) {
83 BOOST_STATIC_ASSERT((num_channels<packed_pixel>::value==3));
84 gil::at_c<0>(*this)=chan0; gil::at_c<1>(*this)=chan1; gil::at_c<2>(*this)=chan2;
85 }
86 packed_pixel(int chan0, int chan1, int chan2, int chan3) : _bitfield(0) {
87 BOOST_STATIC_ASSERT((num_channels<packed_pixel>::value==4));
88 gil::at_c<0>(*this)=chan0; gil::at_c<1>(*this)=chan1; gil::at_c<2>(*this)=chan2; gil::at_c<3>(*this)=chan3;
89 }
90 packed_pixel(int chan0, int chan1, int chan2, int chan3, int chan4) : _bitfield(0) {
91 BOOST_STATIC_ASSERT((num_channels<packed_pixel>::value==5));
92 gil::at_c<0>(*this)=chan0; gil::at_c<1>(*this)=chan1; gil::at_c<2>(*this)=chan2; gil::at_c<3>(*this)=chan3; gil::at_c<4>(*this)=chan4;
93 }
94
95 packed_pixel& operator=(const packed_pixel& p) { _bitfield=p._bitfield; return *this; }
96
97 template <typename P> packed_pixel& operator=(const P& p) { assign(p, mpl::bool_<is_pixel<P>::value>()); return *this; }
98 template <typename P> bool operator==(const P& p) const { return equal(p, mpl::bool_<is_pixel<P>::value>()); }
99
100 template <typename P> bool operator!=(const P& p) const { return !(*this==p); }
101
102private:
103 template <typename Pixel> static void check_compatible() { gil_function_requires<PixelsCompatibleConcept<Pixel,packed_pixel> >(); }
104 template <typename Pixel> void assign(const Pixel& p, mpl::true_) { check_compatible<Pixel>(); static_copy(p,*this); }
105 template <typename Pixel> bool equal(const Pixel& p, mpl::true_) const { check_compatible<Pixel>(); return static_equal(*this,p); }
106
107// Support for assignment/equality comparison of a channel with a grayscale pixel
108 static void check_gray() { BOOST_STATIC_ASSERT((is_same<typename Layout::color_space_t, gray_t>::value)); }
109 template <typename Channel> void assign(const Channel& chan, mpl::false_) { check_gray(); at_c<0>(*this)=chan; }
110 template <typename Channel> bool equal (const Channel& chan, mpl::false_) const { check_gray(); return at_c<0>(*this)==chan; }
111public:
112 packed_pixel& operator= (int chan) { check_gray(); at_c<0>(*this)=chan; return *this; }
113 bool operator==(int chan) const { check_gray(); return at_c<0>(*this)==chan; }
114};
115
116/////////////////////////////
117// ColorBasedConcept
118/////////////////////////////
119
120template <typename BitField, typename ChannelRefVec, typename Layout, int K>
121struct kth_element_type<packed_pixel<BitField,ChannelRefVec,Layout>,K> : public mpl::at_c<ChannelRefVec,K> {};
122
123template <typename BitField, typename ChannelRefVec, typename Layout, int K>
124struct kth_element_reference_type<packed_pixel<BitField,ChannelRefVec,Layout>,K> : public mpl::at_c<ChannelRefVec,K> {};
125
126template <typename BitField, typename ChannelRefVec, typename Layout, int K>
127struct kth_element_const_reference_type<packed_pixel<BitField,ChannelRefVec,Layout>,K> {
128 typedef typename channel_traits<typename mpl::at_c<ChannelRefVec,K>::type>::const_reference type;
129};
130
131template <int K, typename P, typename C, typename L> inline
132typename kth_element_reference_type<packed_pixel<P,C,L>, K>::type
133at_c(packed_pixel<P,C,L>& p) {
134 return typename kth_element_reference_type<packed_pixel<P,C,L>, K>::type(&p._bitfield);
135}
136
137template <int K, typename P, typename C, typename L> inline
138typename kth_element_const_reference_type<packed_pixel<P,C,L>, K>::type
139at_c(const packed_pixel<P,C,L>& p) {
140 return typename kth_element_const_reference_type<packed_pixel<P,C,L>, K>::type(&p._bitfield);
141}
142
143/////////////////////////////
144// PixelConcept
145/////////////////////////////
146
147// Metafunction predicate that flags packed_pixel as a model of PixelConcept. Required by PixelConcept
148template <typename BitField, typename ChannelRefVec, typename Layout>
149struct is_pixel<packed_pixel<BitField,ChannelRefVec,Layout> > : public mpl::true_{};
150
151/////////////////////////////
152// PixelBasedConcept
153/////////////////////////////
154
155template <typename P, typename C, typename Layout>
156struct color_space_type<packed_pixel<P,C,Layout> > {
157 typedef typename Layout::color_space_t type;
158};
159
160template <typename P, typename C, typename Layout>
161struct channel_mapping_type<packed_pixel<P,C,Layout> > {
162 typedef typename Layout::channel_mapping_t type;
163};
164
165template <typename P, typename C, typename Layout>
166struct is_planar<packed_pixel<P,C,Layout> > : mpl::false_ {};
167
168
169////////////////////////////////////////////////////////////////////////////////
170///
171/// Support for interleaved iterators over packed pixel
172///
173////////////////////////////////////////////////////////////////////////////////
174
175/// \defgroup PixelIteratorModelPackedInterleavedPtr Pointer to packed_pixel<P,CR,Layout>
176/// \ingroup PixelIteratorModel
177/// \brief Iterators over interleaved pixels.
178/// The pointer packed_pixel<P,CR,Layout>* is used as an iterator over interleaved pixels of packed format. Models PixelIteratorConcept, HasDynamicXStepTypeConcept, MemoryBasedIteratorConcept
179
180template <typename P, typename C, typename L>
181struct iterator_is_mutable<packed_pixel<P,C,L>*> : public mpl::bool_<packed_pixel<P,C,L>::is_mutable> {};
182template <typename P, typename C, typename L>
183struct iterator_is_mutable<const packed_pixel<P,C,L>*> : public mpl::false_ {};
184
185
186
187} } // namespace boost::gil
188
189namespace boost {
190 template <typename P, typename C, typename L>
191 struct has_trivial_constructor<gil::packed_pixel<P,C,L> > : public has_trivial_constructor<P> {};
192}
193#endif
194

source code of boost/boost/gil/packed_pixel.hpp