template< typename Image
        , typename FormatTag
        >
void test_scanline_reader( const char* file_name )
{
    using namespace boost::gil;

    // read image using scanline_read_iterator
    typedef scanline_reader< typename get_read_device< const char*
                                                     , FormatTag
                                                     >::type
                           , FormatTag
                           > reader_t;

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

    Image dst( reader._info._width, reader._info._height );
    vector< byte_t > buffer( reader._scanline_length );

    typedef scanline_read_iterator< reader_t > iterator_t;

    iterator_t it  = iterator_t( reader, &buffer.front() );
    iterator_t end = iterator_t();

    for( int row = 0; it != end; ++it, ++row )
    {
        copy_pixels( interleaved_view( reader._info._width
                                     , 1
                                     , ( typename Image::view_t::x_iterator ) *it
                                     , reader._scanline_length
                                     )
                   , subimage_view( view( dst )
                                  , 0
                                  , row
                                  , reader._info._width
                                  , 1
                                  )
                   );
    }

    //compare
    Image img;
    read_image( file_name, img, FormatTag() );

    cmp_view( view( dst ), view( img ) );
}