http://lists.boost.org/Archives/boost/2013/02/200965.php

boost_gil_scanline_read_iterator_example.cpp

#include <boost/gil/gil_all.hpp>
#include <boost/gil/extension/io_new/bmp_all.hpp>

using namespace std;
using namespace boost;
using namespace gil;

int main()
{
    typedef rgb8_image_t image_t;

    // read image using scanline_read_iterator
    const char* file_name = "";

    typedef scanline_reader
        <
        typename get_read_device<const char*, bmp_tag>::type, bmp_tag
        > reader_t;

    reader_t reader = make_scanline_reader( file_name, bmp_tag() );

    image_t dst( reader._info._width, reader._info._height );
    byte_t* buffer = new byte_t[ reader._scanline_length ];

    scanline_read_iterator< reader_t > it  = scanline_read_iterator< reader_t >( reader, buffer );
    scanline_read_iterator< reader_t > end = scanline_read_iterator< reader_t >();

    int row = 0;
    while( it != end )
    {
        *it;

        copy_pixels(
            interleaved_view(reader._info._width, 1, (image_t::view_t::x_iterator) buffer, reader._scanline_length)
            , subimage_view(view(dst), 0, row, reader._info._width, 1));

        ++row;
    }

    return 0;
}