libs/gil/example/x_gradient.cpp
/*
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;
}