#!/usr/pkg/bin/perl
use strict;
my($VERSION);
$VERSION = "2024-02-17 23:28" ; # written by emacs time-stamp
## $VERSION .= ' UTC';
$VERSION =~ s/ /-/g;
$VERSION =~ s/:/./g;

sub box  {
    my ($arg_ptr) = @_;
    my $width    = $arg_ptr -> { -width};
    my $length   = $arg_ptr -> { -length};
    my $value    = $arg_ptr -> { -value};
    my $gap      = $arg_ptr -> { -gap};
   foreach my $i (0..$length - 1) {
       foreach my $j (0..$width - 1) { print PGM  $value . ' ' ; }
       foreach my $g (0..$gap-1    ) { print PGM  '00 ' ;        }
       foreach my $j (0..$width - 1) { print PGM  $value . ' ' ; }
       print PGM  "\n";
   }
}
    
sub main()  {

    my $max     = 127;  # bmp light value
    my $width   = 250;
    my $length_posi  = 100;
    my $length_nega  = 100;
    my $slant_length = 600;
    my $gap     = 50;


    my $totalW  = $width * 2 + $gap;
    my $ref_length = $length_posi + $length_nega;

    my $totalH  = $ref_length * 2 + $slant_length;

    my $base_name  =  'cross_x2';
    $base_name = sprintf("cross_x2-%d-%d", $totalW, $totalH);

    $base_name .=  '-'. $VERSION;  
    my $pgm_name .=  $base_name . '.pgm';
    my $bmp_name .=  $base_name . '.bmp';

        open(PGM, "> $pgm_name") || die "problem opening file to write: $!\n";
    print $bmp_name,"\n";  # See below after __END__ line


    print PGM  "P2\n";
    printf( PGM " # %2d x %d bitmap PGM format\n", $totalW, $totalH);
    print PGM  $totalW, ' ' . $totalH . "\n";
    print PGM  $max . "\n";

    box ({ -length => $length_posi, -width => $width, -value => $max, -gap=> $gap});
    box ({ -length => $length_nega, -width => $width, -value => 0   , -gap=> $gap});


    foreach my $value (0..$slant_length - 1) {
	my $light_value = int ($value/$slant_length * 128);
##	foreach my $repeat (0,1)  {
	    foreach my $j (0..$width - 1) { print PGM  $light_value        . ' ' ; }
	    foreach my $g (0..$gap   - 1) { print PGM                '00 ' ; }
	    foreach my $j (0..$width - 1) { print PGM  $max - $light_value . ' ' ; }
##	}
	print PGM  "\n";
    }
    box ({ -length => $length_nega, -width => $width, -value => 0   , -gap=> $gap});
    box ({ -length => $length_posi, -width => $width, -value => $max, -gap=> $gap});

    system ("convert $pgm_name $bmp_name") && die "conversion problem: $!\n";
}
main();
__END__

 feh `perl 225x456`


; please note I have copy in ~/.emacs-sub/time-stamp-setup.el
(require 'time-stamp)
(add-hook 'write-file-hooks 'time-stamp)
(setq time-stamp-active t)
;; (setq time-stamp-time-zone "UTC")
(setq time-stamp-time-zone nil)
(setq time-stamp-format "%04y-%02m-%02d %02H:%02M");
(setq time-stamp-start "$VERSION = \"") ;
(setq time-stamp-end "\"") ;
(setq time-stamp-line-limit 20) ; ; default is 8