ansi_rgb

#!/usr/bin/env perl

use strict ;
use warnings ;

# 256colors display index-rgb and small cubes
# 256colors index  display system colors on background index
# 256colors R G B  display system colors on background RGB
 
if(@ARGV == 1)
	{
	my $color = $ARGV[0] ;
	printf "\x1b[38;5;$_;48;5;${color}m %3d Barba tenus sapientes \x1b[0m\n", $_ for (0 .. 15) ;
	}
elsif(@ARGV == 3)
	{
	my $color = 16 + ($ARGV[0] * 36) + ($ARGV[1] * 6) + $ARGV[2] ;

	print "rgb$ARGV[0]$ARGV[1]$ARGV[2] is index $color\n" ;

	printf "\x1b[38;5;$_;48;5;${color}m %3d Barba tenus sapientes \x1b[0m\n", $_ for (0 .. 15) ;
	}
else
	{
	display_all_colors() ;
	}

sub display_all_colors
{

# system colors 
printf "%-2s", $_ for (0 .. 7) ;
print "\n" ;
print "\x1b[48;5;${_}m  " for (0 .. 7) ;
print "\x1b[0m\n";

printf "%-2s", $_ for (8 .. 15) ;
print "\n" ;
print "\x1b[48;5;${_}m  " for (8 .. 15) ;
print "\x1b[0m\n\n";

# color cubes
for my $blue (0, 3) 
	{
	for my $green (0 .. 5) 
		{
		for my $red (0 .. 5) 
			{
			my $color = 16 + ($red * 36) + ($green * 6) + $blue;

			print "\x1b[38;5;88m$red", "\x1b[38;5;28m$green","\x1b[38;5;12m$blue" ;
			printf "\x1b[38;5;240m%3d", $color ;

			print "\x1b[38;5;0;48;5;${color}m x \x1b[0m" ;
			$color++ ;
			print "\x1b[38;5;246;48;5;${color}m x \x1b[0m" ;
			$color++ ;
			print "\x1b[38;5;255;48;5;${color}m x \x1b[0m " ;
			}
		print "\n";
		}

	print "\n";
	}

# grayscale ramp
printf "%-4s", $_ for (0 ..  23) ;
print "\n" ;
printf "%-4s", $_ for (232 ..  255) ;
print "\n" ;
print "\x1b[48;5;${_}m    " for (232 ..  255) ;

}


print "\x1b[0m\n";