[Boost-commit] svn:boost r83495 - trunk/boost/gil/extension/toolbox/color_spaces

Subject: [Boost-commit] svn:boost r83495 - trunk/boost/gil/extension/toolbox/color_spaces
From: chhenning_at_[hidden]
Date: 2013-03-19 11:22:31

Author: chhenning
Date: 2013-03-19 11:22:29 EDT (Tue, 19 Mar 2013)
New Revision: 83495
URL: http://svn.boost.org/trac/boost/changeset/83495

Log:
YCbCr color space.
Added:
   trunk/boost/gil/extension/toolbox/color_spaces/ycbcr.hpp   (contents, props changed)

Added: trunk/boost/gil/extension/toolbox/color_spaces/ycbcr.hpp
==============================================================================
--- (empty file)
+++ trunk/boost/gil/extension/toolbox/color_spaces/ycbcr.hpp	2013-03-19 11:22:29 EDT (Tue, 19 Mar 2013)
@@ -0,0 +1,131 @@
+/*
+    Copyright 2013 Juan V. Puertos G-Cluster, Christian Henning
+    Use, modification and distribution are subject to the Boost Software License,
+    Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
+    http://www.boost.org/LICENSE_1_0.txt).
+*/
+
+/*************************************************************************************************/
+
+#ifndef BOOST_GIL_EXTENSION_TOOLBOX_COLOR_SPACES_YCBCR_HPP
+#define BOOST_GIL_EXTENSION_TOOLBOX_COLOR_SPACES_YCBCR_HPP
+
+////////////////////////////////////////////////////////////////////////////////////////
+/// \file ycbcr.hpp
+/// \brief Support for ycbcr ITU.BT-601 color space
+/// \author Juan V. Puertos G-Cluster 2013 \n
+///
+/// \date 2013 \n
+///
+////////////////////////////////////////////////////////////////////////////////////////
+
+#include <boost/algorithm/clamp.hpp>
+#include <boost/cast.hpp>
+#include <boost/mpl/range_c.hpp>
+#include <boost/mpl/vector_c.hpp>
+#include <boost/gil/gil_all.hpp>
+
+namespace boost{ namespace gil {
+
+/// \addtogroup ColorNameModel
+/// \{
+namespace ycbcr_color_space
+{
+/// \brief Luminance
+struct y_t {};    
+/// \brief Blue chrominance component
+struct cb_t {};
+/// \brief Red chrominance component
+struct cr_t {}; 
+}
+/// \}
+
+/// \ingroup ColorSpaceModel
+typedef boost::mpl::vector3<ycbcr_color_space::y_t, ycbcr_color_space::cb_t, ycbcr_color_space::cr_t> ycbcr_t;
+
+/// \ingroup LayoutModel
+typedef boost::gil::layout<ycbcr_t> ycbcr_layout_t;
+
+//The channel depth is ALWAYS 8bits ofr YCbCr!
+GIL_DEFINE_ALL_TYPEDEFS(8,  ycbcr)
+
+/*
+ * Source: http://en.wikipedia.org/wiki/YCbCr#ITU-R_BT.601_conversion
+ * (using values coming directly from ITU-R BT.601 recommendation)
+ */
+
+/**
+* @brief Convert YCbCr ITU.BT-601 to RGB.
+*/
+template<>
+struct default_color_converter_impl<ycbcr_t, rgb_t>
+{
+	// Note: the RGB_t channels range can be set later on by the users. We dont want to cast to bits8 or anything here.
+	template < typename SRCP, typename DSTP >
+	void operator()( const SRCP& src, DSTP& dst ) const
+	{
+        using namespace boost::algorithm;
+        using namespace boost::gil::ycbcr_color_space;
+
+        typedef channel_type< DSTP >::type dst_channel_t;
+
+        double  y = get_color( src,  y_t() );
+        double cb = get_color( src, cb_t() );
+        double cr = get_color( src, cr_t() );
+
+		get_color(dst, red_t())   = (dst_channel_t) clamp( 1.6438 * ( y - 16.0 ) + 1.5960 * ( cr -128.0 )
+                                                         , 0.0
+                                                         , 255.0
+                                                         );
+
+		get_color(dst, green_t()) = (dst_channel_t) clamp( 1.6438 * ( y - 16.0 ) - 0.3917 * ( cb - 128.0 ) + 0.8129 * ( cr -128.0 )
+                                                         , 0.0
+                                                         , 255.0
+                                                         );
+
+		get_color(dst, blue_t())  = (dst_channel_t) clamp( 1.6438 * ( y - 16.0 ) - 2.0172 * ( cb -128.0 )
+                                                         , 0.0
+                                                         , 255.0
+                                                         );
+	}
+};
+
+/*
+ * Source: http://en.wikipedia.org/wiki/YCbCr#ITU-R_BT.601_conversion
+ * digital Y′CbCr derived from digital R'dG'dB'd 8 bits per sample, each using the full range.
+ * with NO footroom wither headroom.
+ */
+/**
+* @brief Convert RGB to YCbCr ITU.BT-601.
+*/
+template<>
+struct default_color_converter_impl<rgb_t, ycbcr_t>
+{
+	template < typename SRCP, typename DSTP >
+	void operator()( const SRCP& src, DSTP& dst ) const
+	{
+        using namespace boost::gil::ycbcr_color_space;
+
+        typedef channel_type< SRCP >::type src_channel_t;
+        typedef channel_type< DSTP >::type dst_channel_t;
+
+		src_channel_t red   = channel_convert<src_channel_t>( get_color(src,   red_t()));
+		src_channel_t green = channel_convert<src_channel_t>( get_color(src, green_t()));
+		src_channel_t blue  = channel_convert<src_channel_t>( get_color(src,  blue_t()));
+
+		double  y =  16.0 + 0.2567 * red  + 0.5041 * green + 0.0979 * blue;
+		double cb = 128.0 - 0.1482 * red  - 0.2909 * green + 0.4392 * blue;
+		double cr = 128.0 + 0.4392 * red  - 0.3677 * green - 0.0714 * blue;
+
+
+		get_color( dst,  y_t() ) = (dst_channel_t)  y;
+		get_color( dst, cb_t() ) = (dst_channel_t) cb;
+		get_color( dst, cr_t() ) = (dst_channel_t) cr;
+	}
+};
+
+} // namespace gil
+
+} // namespace boost
+
+#endif