//
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// Copyright 2005-2007 Adobe Systems Incorporated
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// Copyright 2019 Mateusz Loskot <mateusz at loskot dot net>
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//
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// Distributed under the Boost Software License, Version 1.0
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// See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt
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//
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#ifndef BOOST_GIL_PIXEL_HPP
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#define BOOST_GIL_PIXEL_HPP
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#include <boost/gil/channel.hpp>
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#include <boost/gil/color_base.hpp>
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#include <boost/gil/color_base_algorithm.hpp>
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#include <boost/gil/concepts.hpp>
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#include <boost/gil/metafunctions.hpp>
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#include <boost/gil/utilities.hpp>
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#include <boost/gil/detail/mp11.hpp>
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#include <functional>
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#include <type_traits>
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namespace boost { namespace gil {
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// Forward-declare gray_t
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struct gray_color_t;
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using gray_t = mp11::mp_list<gray_color_t>;
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template <typename PixelBased> struct color_space_type;
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template <typename PixelBased> struct channel_mapping_type;
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template <typename PixelBased> struct channel_type;
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template <typename PixelBased> struct is_planar;
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template <typename PixelBased>
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struct color_space_type<PixelBased const> : color_space_type<PixelBased> {};
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template <typename PixelBased>
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struct channel_mapping_type<PixelBased const> : channel_mapping_type<PixelBased> {};
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template <typename PixelBased>
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struct channel_type<PixelBased const> : channel_type<PixelBased> {};
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template <typename PixelBased>
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struct is_planar : std::false_type {};
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template <typename PixelBased>
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struct is_planar<PixelBased const> : is_planar<PixelBased> {};
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template <typename T> struct is_pixel : std::false_type {};
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template <typename T> struct is_pixel<T const> : is_pixel<T> {};
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/// \ingroup PixelBasedAlgorithm
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/// \brief Returns the number of channels of a pixel-based GIL construct
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template <typename PixelBased>
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struct num_channels : mp11::mp_size<typename color_space_type<PixelBased>::type>::type {};
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/**
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\addtogroup PixelBasedAlgorithm
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Example:
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\code
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static_assert(num_channels<rgb8_view_t>::value == 3, "");
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static_assert(num_channels<cmyk16_planar_ptr_t>::value == 4, "");
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static_assert(is_planar<rgb16_planar_image_t>::value));
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static_assert(std::is_same<color_space_type<rgb8_planar_ref_t>::type, rgb_t>::value, "");
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static_assert(std::is_same<channel_mapping_type<cmyk8_pixel_t>::type,
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channel_mapping_type<rgba8_pixel_t>::type>::value, "");
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static_assert(std::is_same<channel_type<bgr8_pixel_t>::type, uint8_t>::value, "");
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\endcode
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*/
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/// \defgroup ColorBaseModelPixel pixel
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/// \ingroup ColorBaseModel
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/// \brief A homogeneous color base whose element is a channel value. Models HomogeneousColorBaseValueConcept
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/// \defgroup PixelModelPixel pixel
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/// \ingroup PixelModel
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/// \brief A homogeneous pixel value. Models HomogeneousPixelValueConcept
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/// \ingroup PixelModelPixel ColorBaseModelPixel PixelBasedModel
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/// \brief Represents a pixel value (a container of channels). Models: HomogeneousColorBaseValueConcept, PixelValueConcept, HomogeneousPixelBasedConcept
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///
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/// 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
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/// model \p ChannelConcept. The class \p pixel defines a simple, homogeneous pixel value. It is used to store
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/// 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
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/// 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*
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/// are used as the standard iterator over a row of interleaved homogeneous pixels.
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///
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/// Since \p pixel inherits the properties of color base, assigning, equality comparison and copy-construcion are allowed between compatible pixels.
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/// 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.
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///
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/// 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.
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/// 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)
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/// or get_color<gray_color_t>(gray_pix1) = get_color<gray_color_t>(gray_pix2)
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///
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/// \tparam ChannelValue TODO
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/// \tparam Layout mp11::make_integer_sequence<int, ColorSpace::size>
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template <typename ChannelValue, typename Layout>
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struct pixel :
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detail::homogeneous_color_base
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<
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ChannelValue,
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Layout,
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mp11::mp_size<typename Layout::color_space_t>::value
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>
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{
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private:
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using channel_t = ChannelValue;
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using parent_t = detail::homogeneous_color_base
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<
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ChannelValue,
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Layout,
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mp11::mp_size<typename Layout::color_space_t>::value
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>;
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public:
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using value_type = pixel<ChannelValue, Layout>;
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using reference = value_type&;
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using const_reference = value_type const&;
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static constexpr bool is_mutable = channel_traits<channel_t>::is_mutable;
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pixel() = default;
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explicit pixel(channel_t v) : parent_t(v) {} // sets all channels to v
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pixel(channel_t v0, channel_t v1) : parent_t(v0, v1) {}
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pixel(channel_t v0, channel_t v1, channel_t v2) : parent_t(v0, v1, v2) {}
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pixel(channel_t v0, channel_t v1, channel_t v2, channel_t v3)
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: parent_t(v0, v1, v2, v3)
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{}
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pixel(channel_t v0, channel_t v1, channel_t v2, channel_t v3, channel_t v4)
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: parent_t(v0, v1, v2, v3, v4)
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{}
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pixel(channel_t v0, channel_t v1, channel_t v2, channel_t v3, channel_t v4, channel_t v5)
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: parent_t(v0, v1, v2, v3, v4, v5)
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{}
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pixel(const pixel& p) : parent_t(p) {}
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pixel& operator=(pixel const& p)
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{
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static_copy(p,*this);
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return *this;
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}
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// Construct from another compatible pixel type
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template <typename Pixel>
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pixel(Pixel const& p,
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typename std::enable_if<is_pixel<Pixel>::value>::type* /*dummy*/ = nullptr)
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: parent_t(p)
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{
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check_compatible<Pixel>();
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}
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template <typename Pixel>
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pixel& operator=(Pixel const& p)
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{
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assign(p, is_pixel<Pixel>());
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return *this;
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}
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template <typename Pixel>
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bool operator==(Pixel const& p) const { return equal(p, is_pixel<Pixel>()); }
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template <typename Pixel>
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bool operator!=(Pixel const& p) const { return !(*this == p); }
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// homogeneous pixels have operator[]
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auto operator[](std::size_t index)
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-> typename channel_traits<channel_t>::reference
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{
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return dynamic_at_c(*this, index);
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}
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auto operator[](std::size_t index) const
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-> typename channel_traits<channel_t>::const_reference
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{
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return dynamic_at_c(*this, index);
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}
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private:
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template <typename Pixel>
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void assign(Pixel const& p, std::true_type)
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{
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check_compatible<Pixel>();
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static_copy(p, *this);
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}
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template <typename Pixel>
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bool equal(Pixel const& p, std::true_type) const
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{
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check_compatible<Pixel>();
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return static_equal(*this, p);
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}
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template <typename Pixel>
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void check_compatible() const
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{
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gil_function_requires<PixelsCompatibleConcept<Pixel, pixel>>();
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}
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// Support for assignment/equality comparison of a channel with a grayscale pixel
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private:
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static void check_gray()
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{
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static_assert(std::is_same<typename Layout::color_space_t, gray_t>::value, "");
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}
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template <typename Channel>
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void assign(Channel const& channel, std::false_type)
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{
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check_gray();
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gil::at_c<0>(*this) = channel;
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}
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template <typename Channel>
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bool equal (Channel const& channel, std::false_type) const
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{
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check_gray();
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return gil::at_c<0>(*this) == channel;
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}
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public:
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pixel& operator= (channel_t channel)
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{
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check_gray();
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gil::at_c<0>(*this) = channel;
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return *this;
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}
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bool operator==(channel_t channel) const
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{
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check_gray();
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return gil::at_c<0>(*this) == channel;
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}
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};
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/////////////////////////////
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// ColorBasedConcept
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/////////////////////////////
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template <typename ChannelValue, typename Layout, int K>
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struct kth_element_type<pixel<ChannelValue,Layout>, K>
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{
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using type = ChannelValue;
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};
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template <typename ChannelValue, typename Layout, int K>
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struct kth_element_reference_type<pixel<ChannelValue,Layout>, K>
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{
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using type = typename channel_traits<ChannelValue>::reference;
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};
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template <typename ChannelValue, typename Layout, int K>
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struct kth_element_reference_type<const pixel<ChannelValue,Layout>, K>
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{
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using type = typename channel_traits<ChannelValue>::const_reference;
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};
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template <typename ChannelValue, typename Layout, int K>
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struct kth_element_const_reference_type<pixel<ChannelValue,Layout>, K>
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{
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using type = typename channel_traits<ChannelValue>::const_reference;
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};
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/////////////////////////////
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// PixelConcept
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/////////////////////////////
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template <typename ChannelValue, typename Layout>
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struct is_pixel<pixel<ChannelValue,Layout>> : std::true_type {};
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/////////////////////////////
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// HomogeneousPixelBasedConcept
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/////////////////////////////
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template <typename ChannelValue, typename Layout>
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struct color_space_type<pixel<ChannelValue, Layout>>
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{
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using type = typename Layout::color_space_t;
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};
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template <typename ChannelValue, typename Layout>
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struct channel_mapping_type<pixel<ChannelValue, Layout>>
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{
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using type = typename Layout::channel_mapping_t;
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};
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template <typename ChannelValue, typename Layout>
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struct is_planar<pixel<ChannelValue, Layout>> : std::false_type {};
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template <typename ChannelValue, typename Layout>
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struct channel_type<pixel<ChannelValue, Layout>>
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{
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using type = ChannelValue;
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};
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}} // namespace boost::gil
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#endif
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