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#ifndef GIL_PIXEL_H
13#define GIL_PIXEL_H
14
15////////////////////////////////////////////////////////////////////////////////////////
16/// \file
17/// \brief pixel class and related utilities
18/// \author Lubomir Bourdev and Hailin Jin \n
19/// Adobe Systems Incorporated
20/// \date 2005-2007 \n Last updated on September 28, 2006
21///
22////////////////////////////////////////////////////////////////////////////////////////
23
24#include <functional>
25#include <boost/utility/enable_if.hpp>
26#include <boost/mpl/bool.hpp>
27#include <boost/mpl/front.hpp>
28#include <boost/type_traits.hpp>
29#include "gil_config.hpp"
30#include "color_base.hpp"
31#include "gil_concept.hpp"
32#include "channel.hpp"
33#include "metafunctions.hpp"
34#include "utilities.hpp"
35#include "color_base_algorithm.hpp"
36
37namespace boost { namespace gil {
38
39// Forward-declare gray_t
40struct gray_color_t;
41typedef mpl::vector1<gray_color_t> gray_t;
42template <typename PixelBased> struct color_space_type;
43template <typename PixelBased> struct channel_mapping_type;
44template <typename PixelBased> struct channel_type;
45template <typename PixelBased> struct is_planar;
46
47template <typename PixelBased> struct color_space_type<const PixelBased> : public color_space_type<PixelBased> {};
48template <typename PixelBased> struct channel_mapping_type<const PixelBased> : public channel_mapping_type<PixelBased> {};
49template <typename PixelBased> struct channel_type<const PixelBased> : public channel_type<PixelBased> {};
50
51template <typename PixelBased> struct is_planar : mpl::false_ {};
52template <typename PixelBased> struct is_planar<const PixelBased> : public is_planar<PixelBased> {};
53
54
55template <typename T> struct is_pixel : public mpl::false_{};
56template <typename T> struct is_pixel<const T> : public is_pixel<T> {};
57
58/// \ingroup PixelBasedAlgorithm
59/// \brief Returns the number of channels of a pixel-based GIL construct
60template <typename PixelBased>
61struct num_channels : public mpl::size<typename color_space_type<PixelBased>::type> {};
62
63/**
64\addtogroup PixelBasedAlgorithm
65
66Example:
67\code
68BOOST_STATIC_ASSERT((num_channels<rgb8_view_t>::value==3));
69BOOST_STATIC_ASSERT((num_channels<cmyk16_planar_ptr_t>::value==4));
70
71BOOST_STATIC_ASSERT((is_planar<rgb16_planar_image_t>::value));
72BOOST_STATIC_ASSERT((is_same<color_space_type<rgb8_planar_ref_t>::type, rgb_t>::value));
73BOOST_STATIC_ASSERT((is_same<channel_mapping_type<cmyk8_pixel_t>::type,
74 channel_mapping_type<rgba8_pixel_t>::type>::value));
75BOOST_STATIC_ASSERT((is_same<channel_type<bgr8_pixel_t>::type, bits8>::value));
76\endcode
77*/
78
79/// \defgroup ColorBaseModelPixel pixel
80/// \ingroup ColorBaseModel
81/// \brief A homogeneous color base whose element is a channel value. Models HomogeneousColorBaseValueConcept
82
83/// \defgroup PixelModelPixel pixel
84/// \ingroup PixelModel
85/// \brief A homogeneous pixel value. Models HomogeneousPixelValueConcept
86
87/// \ingroup PixelModelPixel ColorBaseModelPixel PixelBasedModel
88/// \brief Represents a pixel value (a container of channels). Models: HomogeneousColorBaseValueConcept, PixelValueConcept, HomogeneousPixelBasedConcept
89///
90/// A pixel is a set of channels defining the color at a given point in an image. Conceptually, a pixel is little more than a color base whose elements
91/// model \p ChannelConcept. The class \p pixel defines a simple, homogeneous pixel value. It is used to store
92/// the value of a color. The built-in C++ references to \p pixel, \p pixel& and \p const \p pixel& are used to represent a reference to a pixel
93/// inside an interleaved image view (a view in which all channels are together in memory). Similarly, built-in pointer types \p pixel* and \p const \p pixel*
94/// are used as the standard iterator over a row of interleaved homogeneous pixels.
95///
96/// Since \p pixel inherits the properties of color base, assigning, equality comparison and copy-construcion are allowed between compatible pixels.
97/// This means that an 8-bit RGB pixel may be assigned to an 8-bit BGR pixel, or to an 8-bit planar reference. The channels are properly paired semantically.
98///
99/// The single-channel (grayscale) instantiation of the class pixel, (i.e. \p pixel<T,gray_layout_t>) is also convertible to/from a channel value.
100/// This allows grayscale pixels to be used in simpler expressions like *gray_pix1 = *gray_pix2 instead of more complicated at_c<0>(gray_pix1) = at_c<0>(gray_pix2)
101/// or get_color<gray_color_t>(gray_pix1) = get_color<gray_color_t>(gray_pix2)
102
103template <typename ChannelValue, typename Layout> // = mpl::range_c<int,0,ColorSpace::size> >
104struct pixel : public detail::homogeneous_color_base<ChannelValue,Layout,mpl::size<typename Layout::color_space_t>::value> {
105private:
106 typedef ChannelValue channel_t;
107 typedef detail::homogeneous_color_base<ChannelValue,Layout,mpl::size<typename Layout::color_space_t>::value> parent_t;
108public:
109 typedef pixel value_type;
110 typedef value_type& reference;
111 typedef const value_type& const_reference;
112 BOOST_STATIC_CONSTANT(bool, is_mutable = channel_traits<channel_t>::is_mutable);
113
114 pixel(){}
115 explicit pixel(channel_t v) : parent_t(v) {} // sets all channels to v
116 pixel(channel_t v0, channel_t v1) : parent_t(v0,v1) {}
117 pixel(channel_t v0, channel_t v1, channel_t v2) : parent_t(v0,v1,v2) {}
118 pixel(channel_t v0, channel_t v1, channel_t v2, channel_t v3) : parent_t(v0,v1,v2,v3) {}
119 pixel(channel_t v0, channel_t v1, channel_t v2, channel_t v3, channel_t v4) : parent_t(v0,v1,v2,v3,v4) {}
120 pixel(channel_t v0, channel_t v1, channel_t v2, channel_t v3, channel_t v4, channel_t v5) : parent_t(v0,v1,v2,v3,v4,v5) {}
121
122 pixel(const pixel& p) : parent_t(p) {}
123 pixel& operator=(const pixel& p) { static_copy(p,*this); return *this; }
124
125 // Construct from another compatible pixel type
126 template <typename Pixel> pixel(const Pixel& p, typename enable_if_c<is_pixel<Pixel>::value>::type* dummy = 0) : parent_t(p) {
127 check_compatible<Pixel>();
128 }
129
130 template <typename P> pixel& operator=(const P& p) { assign(p, mpl::bool_<is_pixel<P>::value>()); return *this; }
131 template <typename P> bool operator==(const P& p) const { return equal(p, mpl::bool_<is_pixel<P>::value>()); }
132
133 template <typename P> bool operator!=(const P& p) const { return !(*this==p); }
134
135 // homogeneous pixels have operator[]
136 typename channel_traits<channel_t>::reference operator[](std::size_t i) { return dynamic_at_c(*this,i); }
137 typename channel_traits<channel_t>::const_reference operator[](std::size_t i) const { return dynamic_at_c(*this,i); }
138private:
139 template <typename Pixel> void assign(const Pixel& p, mpl::true_) { check_compatible<Pixel>(); static_copy(p,*this); }
140 template <typename Pixel> bool equal(const Pixel& p, mpl::true_) const { check_compatible<Pixel>(); return static_equal(*this,p); }
141
142 template <typename Pixel> void check_compatible() const { gil_function_requires<PixelsCompatibleConcept<Pixel,pixel> >(); }
143
144// Support for assignment/equality comparison of a channel with a grayscale pixel
145
146private:
147 static void check_gray() { BOOST_STATIC_ASSERT((is_same<typename Layout::color_space_t, gray_t>::value)); }
148 template <typename Channel> void assign(const Channel& chan, mpl::false_) { check_gray(); gil::at_c<0>(*this)=chan; }
149 template <typename Channel> bool equal (const Channel& chan, mpl::false_) const { check_gray(); return gil::at_c<0>(*this)==chan; }
150public:
151 pixel& operator= (channel_t chan) { check_gray(); gil::at_c<0>(*this)=chan; return *this; }
152 bool operator==(channel_t chan) const { check_gray(); return gil::at_c<0>(*this)==chan; }
153};
154
155/////////////////////////////
156// ColorBasedConcept
157/////////////////////////////
158
159template <typename ChannelValue, typename Layout, int K>
160struct kth_element_type<pixel<ChannelValue,Layout>, K> {
161 typedef ChannelValue type;
162};
163
164template <typename ChannelValue, typename Layout, int K>
165struct kth_element_reference_type<pixel<ChannelValue,Layout>, K> {
166 typedef typename channel_traits<ChannelValue>::reference type;
167};
168
169template <typename ChannelValue, typename Layout, int K>
170struct kth_element_reference_type<const pixel<ChannelValue,Layout>, K> {
171 typedef typename channel_traits<ChannelValue>::const_reference type;
172};
173
174template <typename ChannelValue, typename Layout, int K>
175struct kth_element_const_reference_type<pixel<ChannelValue,Layout>, K> {
176 typedef typename channel_traits<ChannelValue>::const_reference type;
177};
178
179/////////////////////////////
180// PixelConcept
181/////////////////////////////
182
183template <typename ChannelValue, typename Layout>
184struct is_pixel<pixel<ChannelValue,Layout> > : public mpl::true_{};
185
186/////////////////////////////
187// HomogeneousPixelBasedConcept
188/////////////////////////////
189
190template <typename ChannelValue, typename Layout>
191struct color_space_type<pixel<ChannelValue,Layout> > {
192 typedef typename Layout::color_space_t type;
193};
194
195template <typename ChannelValue, typename Layout>
196struct channel_mapping_type<pixel<ChannelValue,Layout> > {
197 typedef typename Layout::channel_mapping_t type;
198};
199
200template <typename ChannelValue, typename Layout>
201struct is_planar<pixel<ChannelValue,Layout> > : public mpl::false_ {};
202
203template <typename ChannelValue, typename Layout>
204struct channel_type<pixel<ChannelValue,Layout> > {
205 typedef ChannelValue type;
206};
207
208} } // namespace boost::gil
209
210namespace boost {
211 template <typename ChannelValue, typename Layout>
212 struct has_trivial_constructor<gil::pixel<ChannelValue,Layout> > : public has_trivial_constructor<ChannelValue> {};
213}
214#endif
215

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