/* Copyright 2005-2007 Adobe Systems Incorporated 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). See http://opensource.adobe.com/gil for most recent version including documentation. */ /*************************************************************************************************/ /// \file /// \brief Example file to demonstrate a way to compute gradients along x-axis /// \author Lubomir Bourdev and Hailin Jin /// \date October 19, 2006 #include <boost/gil/extension/io/jpeg_dynamic_io.hpp> using namespace boost::gil; template <typename Out> struct halfdiff_cast_channels { template <typename T> Out operator()(const T& in1, const T& in2) const { return Out((in2-in1)/2); } }; template <typename SrcView, typename DstView> void x_gradient(const SrcView& src, const DstView& dst) { typedef typename channel_type<DstView>::type dst_channel_t; for (int y=0; y<src.height(); ++y) { typename SrcView::x_iterator src_it = src.row_begin(y); typename DstView::x_iterator dst_it = dst.row_begin(y); for (int x=1; x<src.width()-1; ++x) { static_transform(src_it[x-1], src_it[x+1], dst_it[x], halfdiff_cast_channels<dst_channel_t>()); } } } template <typename SrcView, typename DstView> void x_luminosity_gradient(const SrcView& src, const DstView& dst) { typedef pixel<typename channel_type<SrcView>::type, gray_layout_t> gray_pixel_t; x_gradient(color_converted_view<gray_pixel_t>(src), dst); } int main() { rgb8_image_t img; jpeg_read_image("test.jpg",img); gray8s_image_t img_out(img.dimensions()); fill_pixels(view(img_out),bits8s(0)); x_luminosity_gradient(const_view(img), view(img_out)); jpeg_write_view("out-x_gradient.jpg",color_converted_view<gray8_pixel_t>(const_view(img_out))); return 0; }