#!/usr/bin/perl
# Steve Flitman - released to Public Domain - display a small image on the console using 256-color mode Putty/Screen
# Color output to terminal derived from Todd Larason <jtl@molehill.org>

use strict;
use warnings;
use GD;

unless (@ARGV) {
   die "img file ...\nDisplay files at command line using ANSI 256 color mode\n";
}

# set colors 16-231 to a 6x6x6 color cube
for (my $red=0; $red<6; $red++) {
    for (my $green=0; $green<6; $green++) {
        for (my $blue=0; $blue<6; $blue++) {
            printf("\x1b]4;%d;rgb:%2.2x/%2.2x/%2.2x\x1b\\",
                   16 + ($red * 36) + ($green * 6) + $blue,
                   ($red ? ($red * 40 + 55) : 0),
                   ($green ? ($green * 40 + 55) : 0),
                   ($blue ? ($blue * 40 + 55) : 0));
        }
    }
}

# colors 232-255 are a grayscale ramp, intentionally leaving out black and white
for (my $gray=0; $gray<24; $gray++) {
    my $level=($gray * 10) + 8;
    printf("\x1b]4;%d;rgb:%2.2x/%2.2x/%2.2x\x1b\\",
           232 + $gray, $level, $level, $level);
}

my ($file,$x,$y,$r,$g,$b,$color,$index,$image,$width,$height);
for $file (@ARGV) {
   die "Cannot read $file: $!\n" unless -r $file;
   my $image=GD::Image->new($file);
   die "Not a recognized image format: $file\n" unless defined $image;
   my ($width,$height)=$image->getBounds();
   for (my $y=0; $y<$height; $y++) {
      for (my $x=0; $x<$width; $x++) {
         my $index=$image->getPixel($x,$y);
         my ($r,$g,$b)=$image->rgb($index);
         if ($r+$g+$b==0) {   # black
            $color=0;
         }
         elsif ($r==255 && $g==255 && $b==255) {   # white
            $color=15;
         }
         elsif ($r==$g && $g==$b) {  # grayscale
            $color=232+($r>>3);
         } else {
            $color=16+(int($r/42.6)*36)+(int($g/42.6)*6)+int($b/42.6);    # smush 256 color range to 6 levels
         }
         print "\x1b[48;5;${color}m ";
      }
      print "\x1b[0m\n";  # reset
   }
   print "\x1b[0m\n";  # reset
}
exit;