##################################
########### Deal with image
##################################

use PDL::IO::FlexRaw;

my $image;
{
    my $im = Imager-> new( file => $image_file )
        -> to_rgb8
        -> convert( preset => 'noalpha' )
        -> scale( xscalefactor => 1, 
                  yscalefactor => 1 / $distortion );

    my $w_r   = $cols / $im-> getwidth;
    my $h_r   = $rows / $im-> getheight;
    my $ratio = $w_r < $h_r ? $w_r : $h_r;
    $im = $im-> scale( scalefactor => $ratio ) if $ratio < 1;

    $im-> write( data => \my $buf, type => 'raw' );
    my $dims = [ 3, $im-> getwidth, $im-> getheight ];
    open my $fh, '<:raw', \$buf;
    $image = readflex( $fh, [{ Type => 'byte', Dims => $dims }])
}