Graphics::ColorUtils - Easy-to-use color space conversions and more.

  use Graphics::ColorUtils;

  ( $y, $i, $q ) = rgb2yiq( $r, $g, $b );
  ( $r, $g, $b ) = yiq2rgb( $y, $i, $q );
  $hex_string    = yiq2rgb( $y, $i, $q );

  ( $c, $m, $y ) = rgb2cmy( $r, $g, $b );
  ( $r, $g, $b ) = cmy2rgb( $c, $m, $y );
  $hex_string    = cmy2rgb( $c, $m, $y );

  ( $h, $l, $s ) = rgb2hls( $r, $g, $b );
  ( $r, $g, $b ) = hls2rgb( $h, $l, $s );
  $hex_string    = hls2rgb( $h, $l, $s );

  ( $h, $s, $v ) = rgb2hsv( $r, $g, $b );
  ( $r, $g, $b ) = hsv2rgb( $h, $s, $v );
  $hex_string    = hsv2rgb( $h, $s, $v );

  # -----

  use Graphics::ColorUtils qw( :gradients );

  ( $r, $g, $b ) = grad2rgb( $name, $f );  # where 0.0 <= $f < 1.0
  $hex_string    = grad2rgb( $name, $f );

  %color_count_for_gradient_name = available_gradients();
  $array_ref_of_rgb_triples      = gradient( $name );
  $array_ref_old_grad            = register_gradient( $name, $array_ref_of_rgb_triples ); 

  # -----

  use Graphics::ColorUtils qw( :names );

  ( $r, $g, $b ) = name2rgb( $name );
  $hex_string    = name2rgb( $name );

  $hash_ref_rgb_triples_for_name = available_names();
  ( $old_r, $old_g, $old_b )     = register_name( $name, $r, $g, $b );
  $old_hex_string                = register_name( $name, $r, $g, $b );
  $default_ns                    = get_default_namespace();
  $old_ns                        = set_default_namespace( $new_ns );

  Y, I, Q: 0..1
  C, M, Y: 0..1

  R, G, B: 0..255 (may be float on input, guaranteed int on output)

  H:       0..360 (red=0->yellow->green=120->cyan->blue=240->magenta steps of 60)
  S, V:    0..1
  L, S:    0..1

  rgb2yiq(), yiq2rgb()
  rgb2cmy(), cmy2rgb()
  rgb2hls(), hls2rgb()
  rgb2hsv(), hsv2rgb()

  name2rgb()
  available_names()
  register_name()
  set_default_namespace()
  get_default_namespace()

  gradient()
  grad2rgb()
  available_gradients()
  register_gradient()

package Graphics::ColorUtils;

use 5.008003;
use strict;
use warnings;

use Carp;

require Exporter;

our @ISA = qw(Exporter);

our %EXPORT_TAGS = ( 'gradients' => [ qw( gradient
					  grad2rgb
					  available_gradients
					  register_gradient) ],
		     'names' => [ qw( name2rgb
				      available_names
				      register_name
				      set_default_namespace
				      get_default_namespace ) ],
		     'all' => [ qw( rgb2yiq yiq2rgb
				    rgb2cmy cmy2rgb
				    rgb2hls hls2rgb
				    rgb2hsv hsv2rgb
				    gradient
				    grad2rgb
				    available_gradients
				    register_gradient
				    name2rgb
				    available_names
				    register_name
				    set_default_namespace
				    get_default_namespace ) ],
		   );

our @EXPORT_OK = ( @{ $EXPORT_TAGS{'all'} } );

our @EXPORT = qw( rgb2yiq yiq2rgb
		  rgb2cmy cmy2rgb
		  rgb2hls hls2rgb
		  rgb2hsv hsv2rgb );

our $VERSION = '0.17';

# ==================================================
# ++++++++++++++++++++++++++++++++++++++++++++++++++
# ==================================================

# ==================================================
# Utility

# Takes a (r,g,b) triple of numbers (possibly floats) and returns
# - a string like '#33FF21' in scalar context
# - a triple of corresponding integers in array context
sub _fmt {
  return wantarray ? map { int } @_ : sprintf( "#%02x%02x%02x", @_ );
}

# ==================================================
# YIQ

sub rgb2yiq {
  # $r, $g, $b : 0..255
  my ( $r, $g, $b ) = map { $_/255.0 } @_;          # Scale RGB to 0..1

  my $y = 0.299*$r + 0.587*$g + 0.114*$b;
  my $i = 0.596*$r - 0.275*$g - 0.321*$b;
  my $q = 0.212*$r - 0.523*$g + 0.311*$b;

  return ( $y, $i, $q );
}

sub yiq2rgb {
  # $y, $i, $q : 0..1
  my ( $y, $i, $q ) = @_;

  my $r = 255.0*( $y + 0.956*$i + 0.621*$q );
  my $g = 255.0*( $y - 0.272*$i - 0.647*$q );
  my $b = 255.0*( $y - 1.105*$i + 1.705*$q );

  return _fmt( $r, $g, $b );
}

# ==================================================
# CMY

sub rgb2cmy {
  # $r, $g, $b : 0..255
  my ( $r, $g, $b ) = map { $_/255.0 } @_;          # Scale RGB to 0..1

  return ( 1.0 - $r, 1.0 - $g, 1.0 - $b );
}

sub cmy2rgb {
  # $c, $m, $y : 0..1
  my ( $c, $m, $y ) = @_;

  return _fmt( 255*(1.0-$c), 255*(1.0-$m), 255*(1.0-$y) );
}

# ==================================================
# HLS

# Foley, van Dam, et al:
# Computer Grapics-Principles and Practice (1990) p595f

sub rgb2hls {
  # $r, $g, $b : 0..255
  #   Note special name '$bb' to avoid conflict with ($a,$b) in sort()
  my ( $r, $g, $bb ) = map { $_/255.0 } @_;         # Scale RGB to 0..1

  my ( $minc, $maxc ) = ( sort { $a <=> $b } ( $r, $g, $bb ) )[0,2];

  my $m = $minc + $maxc;                            # "Mean"

  if( $maxc == $minc ) { return ( 0, 0.5*$m, 0 ); } # Achromatic case

  my $d = $maxc - $minc;                            # "Delta"
  my $s = ( $m <= 1.0 ) ? $d/$m : $d/(2.0-$m );     # Saturation

  my $h = 0;                                        # Hue
  if(    $r  == $maxc ) { $h =     ( $g-$bb )/$d; }
  elsif( $g  == $maxc ) { $h = 2 + ( $bb-$r )/$d; }
  elsif( $bb == $maxc ) { $h = 4 + ( $r-$g )/$d; }
  else {
    # Never get here!
    croak "Internal Error: Unexpected value ,$maxc, in Graphics::ColorUtils::rgb2hls( $r, $g, $bb )";
  }

  $h *= 60;                                         # Convert to degrees
  if( $h < 0 ) { $h += 360; }                       # Ensure positive hue

  return ( $h, 0.5*$m, $s );
}

sub hls2rgb {
  # $h: 0..360 (red=0->yellow->green=120->cyan->blue=240->magenta steps of 60)
  # $l, $s : 0..1 (inclusive)
  my ( $h, $l, $s ) = @_;

  if( $s == 0.0 ) { return _fmt(255*$l, 255*$l, 255*$l); } # achromatic (grey)

# This is the INCORRECT line as it is in the book quoted above:
# my $m2 = ( $l <= 0.5 ) ? ($l*($l+$s)) : ($l - $l*$s + $s);
# This is the CORRECT line: (first alternative: 1 vs $l)
  my $m2 = ( $l <= 0.5 ) ? ($l*(1+$s)) : ($l - $l*$s + $s);
  my $m1 = 2.0*$l - $m2;

  my $r = 255 * _value( $m1, $m2, $h + 120 );
  my $g = 255 * _value( $m1, $m2, $h );
  my $b = 255 * _value( $m1, $m2, $h - 120 );

  return _fmt( $r, $g, $b );
}

sub _value {
  my ( $n1, $n2, $hue ) = @_;

  if(    $hue > 360 ) { $hue -= 360; }
  elsif( $hue <   0 ) { $hue += 360; }

  if(    $hue <  60 ) { return $n1 + $hue * ( $n2-$n1 )/60.0; }
  elsif( $hue < 180 ) { return $n2; }
  elsif( $hue < 240 ) { return $n1 + ( 240-$hue ) * ( $n2-$n1 )/60.0; }
  else                { return $n1; }
}

# ==================================================
# HSV

# Foley, van Dam, et al:
# Computer Grapics-Principles and Practice (1990) p592f

sub rgb2hsv {
  # $r, $g, $b : 0..25
  #   Note special name '$bb' to avoid conflict with ($a,$b) in sort()
  my ( $r, $g, $bb ) = map { $_/255.0 } @_; # Scale RGB to 0..1

  my ( $minc, $maxc ) = ( sort { $a <=> $b } ( $r, $g, $bb ) )[0,2];

  my $v = $maxc;                         # Value
  my $d = $maxc - $minc;                 # "Delta"
  my $s = ( $maxc == 0 ) ? 0 : $d/$maxc; # No saturation if R=G=B=0

  if( $s == 0 ) { return ( 0, 0, $v ); } # Achromatic case

  my $h = 0;                             # Hue
  if(    $r == $maxc ) { $h =     ( $g-$bb )/$d; }
  elsif( $g == $maxc ) { $h = 2 + ( $bb-$r )/$d; }
  elsif( $bb == $maxc ) { $h = 4 + ( $r-$g )/$d; }
  else {
    # Never get here!
    croak "Internal Error: Unexpected value ,$maxc, in Graphics::ColorUtils::rgb2hsv( $r, $g, $bb )";
  }

  $h *= 60;                              # Convert to degrees
  if( $h < 0 ) { $h += 360; }            # Ensure positive hue

  return ( $h, $s, $v );
}

sub hsv2rgb {
  # $h: 0..360 (red=0->yellow->green=120->cyan->blue=240->magenta steps of 60)
  #     (tolerates larger values of $h by reducing them to the standard circle)
  # $s, $v : 0..1 (inclusive)
  my ( $h, $s, $v ) = @_;

  $v *= 255;
  if( $s == 0 ) { return _fmt( $v, $v, $v ); } # achromatic (grey)

  my $i = int( $h/60 );  # sector 0 to 5
  my $f = ($h/60) - $i;  # fractional part of h/60

  my $p = $v * ( 1 - $s );
  my $q = $v * ( 1 - $s * $f );
  my $t = $v * ( 1 - $s * ( 1 - $f ) );

  $i %= 6;               # tolerate values of $h larger than 360
  if(    $i==0 ) { return _fmt( $v, $t, $p ); }
  elsif( $i==1 ) { return _fmt( $q, $v, $p ); }
  elsif( $i==2 ) { return _fmt( $p, $v, $t ); }
  elsif( $i==3 ) { return _fmt( $p, $q, $v ); }
  elsif( $i==4 ) { return _fmt( $t, $p, $v ); }
  elsif( $i==5 ) { return _fmt( $v, $p, $q ); }
  else { 
    # Never get here!
    croak "Internal Error: Unexpected value ,$i, in Graphics::ColorUtils::hsv2rgb( $h, $s, $v )";
  }
}

# ==================================================
# Gradients

# Gradients grey, heat, map, and rainbow have been inspired by similar 
# ideas in Yorick. 
# For Yorick, cf http://yorick.sourceforge.net 
# and also http://www.maumae.net/yorick/doc/index.php
# as well as http://www.mhatt.aps.anl.gov/dohn/software/yorick/

BEGIN {
my %_gradients = (
		  'grey' => [
	[  0,  0,  0],[  1,  1,  1],[  2,  2,  2],[  3,  3,  3],[  4,  4,  4],
	[  5,  5,  5],[  6,  6,  6],[  7,  7,  7],[  9,  9,  9],[ 10, 10, 10],
	[ 11, 11, 11],[ 12, 12, 12],[ 13, 13, 13],[ 14, 14, 14],[ 15, 15, 15],
	[ 16, 16, 16],[ 17, 17, 17],[ 18, 18, 18],[ 19, 19, 19],[ 20, 20, 20],
	[ 21, 21, 21],[ 22, 22, 22],[ 23, 23, 23],[ 25, 25, 25],[ 26, 26, 26],
	[ 27, 27, 27],[ 28, 28, 28],[ 29, 29, 29],[ 30, 30, 30],[ 31, 31, 31],
	[ 32, 32, 32],[ 33, 33, 33],[ 34, 34, 34],[ 35, 35, 35],[ 36, 36, 36],
	[ 37, 37, 37],[ 38, 38, 38],[ 39, 39, 39],[ 41, 41, 41],[ 42, 42, 42],
	[ 43, 43, 43],[ 44, 44, 44],[ 45, 45, 45],[ 46, 46, 46],[ 47, 47, 47],
	[ 48, 48, 48],[ 49, 49, 49],[ 50, 50, 50],[ 51, 51, 51],[ 52, 52, 52],
	[ 53, 53, 53],[ 54, 54, 54],[ 55, 55, 55],[ 57, 57, 57],[ 58, 58, 58],
	[ 59, 59, 59],[ 60, 60, 60],[ 61, 61, 61],[ 62, 62, 62],[ 63, 63, 63],
	[ 64, 64, 64],[ 65, 65, 65],[ 66, 66, 66],[ 67, 67, 67],[ 68, 68, 68],
	[ 69, 69, 69],[ 70, 70, 70],[ 71, 71, 71],[ 73, 73, 73],[ 74, 74, 74],
	[ 75, 75, 75],[ 76, 76, 76],[ 77, 77, 77],[ 78, 78, 78],[ 79, 79, 79],
	[ 80, 80, 80],[ 81, 81, 81],[ 82, 82, 82],[ 83, 83, 83],[ 84, 84, 84],
	[ 85, 85, 85],[ 86, 86, 86],[ 87, 87, 87],[ 89, 89, 89],[ 90, 90, 90],
	[ 91, 91, 91],[ 92, 92, 92],[ 93, 93, 93],[ 94, 94, 94],[ 95, 95, 95],
	[ 96, 96, 96],[ 97, 97, 97],[ 98, 98, 98],[ 99, 99, 99],[100,100,100],
	[101,101,101],[102,102,102],[103,103,103],[105,105,105],[106,106,106],
	[107,107,107],[108,108,108],[109,109,109],[110,110,110],[111,111,111],
	[112,112,112],[113,113,113],[114,114,114],[115,115,115],[116,116,116],
	[117,117,117],[118,118,118],[119,119,119],[121,121,121],[122,122,122],
	[123,123,123],[124,124,124],[125,125,125],[126,126,126],[127,127,127],
	[128,128,128],[129,129,129],[130,130,130],[131,131,131],[132,132,132],
	[133,133,133],[134,134,134],[135,135,135],[137,137,137],[138,138,138],
	[139,139,139],[140,140,140],[141,141,141],[142,142,142],[143,143,143],
	[144,144,144],[145,145,145],[146,146,146],[147,147,147],[148,148,148],
	[149,149,149],[150,150,150],[151,151,151],[153,153,153],[154,154,154],
	[155,155,155],[156,156,156],[157,157,157],[158,158,158],[159,159,159],
	[160,160,160],[161,161,161],[162,162,162],[163,163,163],[164,164,164],
	[165,165,165],[166,166,166],[167,167,167],[169,169,169],[170,170,170],
	[171,171,171],[172,172,172],[173,173,173],[174,174,174],[175,175,175],
	[176,176,176],[177,177,177],[178,178,178],[179,179,179],[180,180,180],
	[181,181,181],[182,182,182],[183,183,183],[185,185,185],[186,186,186],
	[187,187,187],[188,188,188],[189,189,189],[190,190,190],[191,191,191],
	[192,192,192],[193,193,193],[194,194,194],[195,195,195],[196,196,196],
	[197,197,197],[198,198,198],[199,199,199],[201,201,201],[202,202,202],
	[203,203,203],[204,204,204],[205,205,205],[206,206,206],[207,207,207],
	[208,208,208],[209,209,209],[210,210,210],[211,211,211],[212,212,212],
	[213,213,213],[214,214,214],[215,215,215],[217,217,217],[218,218,218],
	[219,219,219],[220,220,220],[221,221,221],[222,222,222],[223,223,223],
	[224,224,224],[225,225,225],[226,226,226],[227,227,227],[228,228,228],
	[229,229,229],[230,230,230],[231,231,231],[233,233,233],[234,234,234],
	[235,235,235],[236,236,236],[237,237,237],[238,238,238],[239,239,239],
	[240,240,240],[241,241,241],[242,242,242],[243,243,243],[244,244,244],
	[245,245,245],[246,246,246],[247,247,247],[249,249,249],[250,250,250],
	[251,251,251],[252,252,252],[253,253,253],[254,254,254],[255,255,255]
			    ],
		  'heat' => [
	[  0,  0,  0],[  1,  0,  0],[  2,  0,  0],[  4,  0,  0],[  5,  0,  0],
	[  7,  0,  0],[  8,  0,  0],[ 10,  0,  0],[ 11,  0,  0],[ 13,  0,  0],
	[ 15,  0,  0],[ 17,  0,  0],[ 18,  0,  0],[ 20,  0,  0],[ 21,  0,  0],
	[ 23,  0,  0],[ 24,  0,  0],[ 26,  0,  0],[ 27,  0,  0],[ 28,  0,  0],
	[ 30,  0,  0],[ 31,  0,  0],[ 33,  0,  0],[ 34,  0,  0],[ 36,  0,  0],
	[ 37,  0,  0],[ 39,  0,  0],[ 40,  0,  0],[ 42,  0,  0],[ 43,  0,  0],
	[ 46,  0,  0],[ 47,  0,  0],[ 49,  0,  0],[ 50,  0,  0],[ 52,  0,  0],
	[ 53,  0,  0],[ 55,  0,  0],[ 56,  0,  0],[ 57,  0,  0],[ 59,  0,  0],
	[ 60,  0,  0],[ 62,  0,  0],[ 63,  0,  0],[ 65,  0,  0],[ 66,  0,  0],
	[ 68,  0,  0],[ 69,  0,  0],[ 70,  0,  0],[ 72,  0,  0],[ 73,  0,  0],
	[ 76,  0,  0],[ 78,  0,  0],[ 79,  0,  0],[ 81,  0,  0],[ 82,  0,  0],
	[ 84,  0,  0],[ 85,  0,  0],[ 86,  0,  0],[ 88,  0,  0],[ 89,  0,  0],
	[ 92,  0,  0],[ 94,  0,  0],[ 95,  0,  0],[ 97,  0,  0],[ 98,  0,  0],
	[ 99,  0,  0],[101,  0,  0],[102,  0,  0],[104,  0,  0],[105,  0,  0],
	[108,  0,  0],[110,  0,  0],[111,  0,  0],[113,  0,  0],[114,  0,  0],
	[115,  0,  0],[117,  0,  0],[118,  0,  0],[120,  0,  0],[121,  0,  0],
	[123,  0,  0],[124,  0,  0],[126,  0,  0],[127,  0,  0],[128,  0,  0],
	[130,  0,  0],[131,  0,  0],[133,  0,  0],[134,  0,  0],[136,  0,  0],
	[139,  0,  0],[140,  0,  0],[141,  0,  0],[143,  0,  0],[144,  0,  0],
	[146,  0,  0],[147,  0,  0],[149,  0,  0],[150,  0,  0],[152,  0,  0],
	[153,  0,  0],[155,  0,  0],[156,  0,  0],[157,  0,  0],[159,  0,  0],
	[160,  0,  0],[162,  0,  0],[163,  0,  0],[165,  0,  0],[166,  0,  0],
	[169,  0,  0],[170,  0,  0],[172,  0,  0],[173,  0,  0],[175,  1,  0],
	[176,  3,  0],[178,  5,  0],[179,  7,  0],[181,  9,  0],[182, 11,  0],
	[185, 15,  0],[186, 17,  0],[188, 18,  0],[189, 20,  0],[191, 22,  0],
	[192, 24,  0],[194, 26,  0],[195, 28,  0],[197, 30,  0],[198, 32,  0],
	[201, 35,  0],[202, 37,  0],[204, 39,  0],[205, 41,  0],[207, 43,  0],
	[208, 45,  0],[210, 47,  0],[211, 49,  0],[212, 51,  0],[214, 52,  0],
	[215, 54,  0],[217, 56,  0],[218, 58,  0],[220, 60,  0],[221, 62,  0],
	[223, 64,  0],[224, 66,  0],[226, 68,  0],[227, 69,  0],[228, 71,  0],
	[231, 75,  0],[233, 77,  0],[234, 79,  0],[236, 81,  0],[237, 83,  0],
	[239, 85,  0],[240, 86,  0],[241, 88,  0],[243, 90,  0],[244, 92,  0],
	[246, 94,  0],[247, 96,  0],[249, 98,  0],[250,100,  0],[252,102,  0],
	[253,103,  0],[255,105,  0],[255,107,  0],[255,109,  0],[255,111,  0],
	[255,115,  0],[255,117,  0],[255,119,  0],[255,120,  0],[255,122,  0],
	[255,124,  0],[255,126,  0],[255,128,  0],[255,130,  0],[255,132,  0],
	[255,136,  7],[255,137, 11],[255,139, 15],[255,141, 19],[255,143, 23],
	[255,145, 27],[255,147, 31],[255,149, 35],[255,151, 39],[255,153, 43],
	[255,156, 51],[255,158, 54],[255,160, 58],[255,162, 62],[255,164, 66],
	[255,166, 70],[255,168, 74],[255,170, 78],[255,171, 82],[255,173, 86],
	[255,175, 90],[255,177, 94],[255,179, 98],[255,181,102],[255,183,105],
	[255,185,109],[255,187,113],[255,188,117],[255,190,121],[255,192,125],
	[255,196,133],[255,198,137],[255,200,141],[255,202,145],[255,204,149],
	[255,205,153],[255,207,156],[255,209,160],[255,211,164],[255,213,168],
	[255,215,172],[255,217,176],[255,219,180],[255,221,184],[255,222,188],
	[255,224,192],[255,226,196],[255,228,200],[255,230,204],[255,232,207],
	[255,236,215],[255,238,219],[255,239,223],[255,241,227],[255,243,231],
	[255,245,235],[255,247,239],[255,249,243],[255,251,247],[255,253,251]
			    ],
		  'map' =>  [
	[  0,  0,  0],[  0,  0, 46],[  0,  0, 58],[  0,  0, 69],[  0,  0, 81],
	[  0,  0, 92],[  0,  0,104],[  0,  0,116],[  0,  3,116],[  1,  6,116],
	[  2,  8,116],[  2, 11,116],[  3, 13,117],[  4, 16,117],[  5, 18,117],
	[  5, 21,117],[  6, 23,117],[  7, 26,118],[  8, 28,118],[  8, 31,118],
	[  9, 33,118],[ 10, 36,118],[ 11, 38,119],[ 11, 41,119],[ 12, 43,119],
	[ 13, 45,119],[ 14, 48,119],[ 15, 50,120],[ 15, 52,120],[ 16, 55,120],
	[ 17, 57,120],[ 18, 59,120],[ 18, 61,121],[ 19, 64,121],[ 20, 66,121],
	[ 21, 68,121],[ 22, 70,121],[ 22, 72,122],[ 23, 74,122],[ 24, 77,122],
	[ 25, 79,122],[ 26, 81,122],[ 26, 83,123],[ 27, 85,123],[ 28, 87,123],
	[ 29, 89,123],[ 30, 91,123],[ 31, 93,124],[ 31, 95,124],[ 32, 97,124],
	[ 33, 99,124],[ 34,100,124],[ 35,102,125],[ 36,104,125],[ 36,106,125],
	[ 37,108,125],[ 38,109,125],[ 39,111,126],[ 40,113,126],[ 41,115,126],
	[ 41,116,126],[ 42,118,126],[ 43,120,127],[ 44,121,127],[ 45,123,127],
	[ 46,125,127],[ 47,126,127],[ 48,128,128],[ 48,128,126],[ 48,129,125],
	[ 49,129,124],[ 49,130,123],[ 50,131,122],[ 50,131,120],[ 51,132,119],
	[ 51,133,118],[ 52,133,117],[ 52,134,115],[ 53,134,114],[ 53,135,113],
	[ 54,136,111],[ 54,136,110],[ 55,137,109],[ 55,138,108],[ 56,138,106],
	[ 56,139,105],[ 57,140,104],[ 57,140,102],[ 58,141,101],[ 58,141,100],
	[ 59,142, 98],[ 59,143, 97],[ 60,143, 96],[ 61,144, 94],[ 61,145, 93],
	[ 62,145, 92],[ 62,146, 90],[ 63,146, 89],[ 63,147, 88],[ 64,148, 86],
	[ 64,148, 85],[ 65,149, 84],[ 65,150, 82],[ 66,150, 81],[ 67,151, 80],
	[ 67,151, 78],[ 68,152, 77],[ 68,153, 76],[ 69,153, 74],[ 69,154, 73],
	[ 70,155, 71],[ 71,155, 70],[ 73,156, 71],[ 76,156, 72],[ 78,157, 72],
	[ 81,158, 73],[ 83,158, 73],[ 86,159, 74],[ 88,160, 75],[ 91,160, 75],
	[ 94,161, 76],[ 96,161, 76],[ 99,162, 77],[101,163, 77],[104,163, 78],
	[106,164, 79],[109,165, 79],[111,165, 80],[114,166, 80],[117,166, 81],
	[119,167, 82],[121,168, 82],[122,168, 82],[124,168, 83],[126,169, 83],
	[128,169, 83],[129,170, 84],[131,170, 84],[133,171, 84],[135,171, 85],
	[136,172, 85],[138,172, 85],[140,172, 86],[141,173, 86],[143,173, 86],
	[145,174, 87],[147,174, 87],[149,175, 87],[150,175, 88],[152,175, 88],
	[154,176, 88],[156,176, 89],[157,177, 89],[159,177, 89],[161,178, 90],
	[163,178, 90],[165,179, 90],[166,179, 91],[168,179, 91],[170,180, 91],
	[172,180, 92],[174,181, 92],[175,181, 92],[177,182, 93],[179,182, 93],
	[181,183, 93],[183,183, 94],[183,182, 94],[184,181, 94],[184,181, 95],
	[185,180, 95],[185,179, 95],[186,178, 96],[186,177, 96],[187,176, 97],
	[187,175, 97],[187,174, 97],[188,173, 98],[188,172, 98],[189,171, 98],
	[189,170, 99],[190,169, 99],[190,168, 99],[190,167,100],[191,166,100],
	[191,165,100],[192,164,101],[192,163,101],[193,163,104],[195,164,106],
	[196,164,108],[197,165,111],[198,165,113],[199,166,116],[201,167,118],
	[202,167,121],[203,168,123],[204,169,126],[205,170,129],[207,171,131],
	[208,172,134],[209,173,137],[210,174,139],[211,175,142],[213,176,145],
	[214,177,148],[215,178,150],[216,179,153],[217,181,156],[219,182,159],
	[220,184,162],[221,185,165],[222,187,168],[223,188,170],[225,190,173],
	[226,192,176],[227,194,179],[228,196,182],[229,198,185],[231,200,189],
	[232,202,192],[233,204,195],[234,206,198],[235,208,201],[237,211,204],
	[238,213,207],[239,215,211],[240,218,214],[241,221,217],[243,223,220],
	[244,226,224],[245,229,227],[246,232,230],[247,235,234],[249,238,237],
	[250,241,241],[251,244,244],[252,248,248],[253,251,251],[255,255,255]
				    ],
		  'rainbow' => [
	[255,  0, 42],[255,  0, 36],[255,  0, 31],[255,  0, 26],[255,  0, 20],
	[255,  0, 15],[255,  0, 10],[255,  0,  4],[255,  5,  0],[255, 11,  0],
	[255, 16,  0],[255, 22,  0],[255, 27,  0],[255, 32,  0],[255, 38,  0],
	[255, 43,  0],[255, 48,  0],[255, 54,  0],[255, 59,  0],[255, 65,  0],
	[255, 70,  0],[255, 75,  0],[255, 81,  0],[255, 91,  0],[255, 97,  0],
	[255,102,  0],[255,108,  0],[255,113,  0],[255,118,  0],[255,124,  0],
	[255,129,  0],[255,135,  0],[255,140,  0],[255,145,  0],[255,151,  0],
	[255,156,  0],[255,161,  0],[255,167,  0],[255,178,  0],[255,183,  0],
	[255,188,  0],[255,194,  0],[255,199,  0],[255,204,  0],[255,210,  0],
	[255,215,  0],[255,221,  0],[255,226,  0],[255,231,  0],[255,237,  0],
	[255,242,  0],[255,247,  0],[255,253,  0],[245,255,  0],[240,255,  0],
	[235,255,  0],[229,255,  0],[224,255,  0],[219,255,  0],[213,255,  0],
	[208,255,  0],[202,255,  0],[197,255,  0],[192,255,  0],[186,255,  0],
	[181,255,  0],[175,255,  0],[170,255,  0],[159,255,  0],[154,255,  0],
	[149,255,  0],[143,255,  0],[138,255,  0],[132,255,  0],[127,255,  0],
	[122,255,  0],[116,255,  0],[111,255,  0],[106,255,  0],[100,255,  0],
	[ 95,255,  0],[ 89,255,  0],[ 84,255,  0],[ 73,255,  0],[ 68,255,  0],
	[ 63,255,  0],[ 57,255,  0],[ 52,255,  0],[ 46,255,  0],[ 41,255,  0],
	[ 36,255,  0],[ 30,255,  0],[ 25,255,  0],[ 19,255,  0],[ 14,255,  0],
	[  9,255,  0],[  3,255,  0],[  0,255,  1],[  0,255, 12],[  0,255, 17],
	[  0,255, 23],[  0,255, 28],[  0,255, 33],[  0,255, 39],[  0,255, 44],
	[  0,255, 49],[  0,255, 55],[  0,255, 60],[  0,255, 66],[  0,255, 71],
	[  0,255, 76],[  0,255, 82],[  0,255, 87],[  0,255, 98],[  0,255,103],
	[  0,255,109],[  0,255,114],[  0,255,119],[  0,255,125],[  0,255,130],
	[  0,255,135],[  0,255,141],[  0,255,146],[  0,255,152],[  0,255,157],
	[  0,255,162],[  0,255,168],[  0,255,173],[  0,255,184],[  0,255,189],
	[  0,255,195],[  0,255,200],[  0,255,205],[  0,255,211],[  0,255,216],
	[  0,255,222],[  0,255,227],[  0,255,232],[  0,255,238],[  0,255,243],
	[  0,255,248],[  0,255,254],[  0,250,255],[  0,239,255],[  0,234,255],
	[  0,228,255],[  0,223,255],[  0,218,255],[  0,212,255],[  0,207,255],
	[  0,201,255],[  0,196,255],[  0,191,255],[  0,185,255],[  0,180,255],
	[  0,174,255],[  0,169,255],[  0,164,255],[  0,153,255],[  0,148,255],
	[  0,142,255],[  0,137,255],[  0,131,255],[  0,126,255],[  0,121,255],
	[  0,115,255],[  0,110,255],[  0,105,255],[  0, 99,255],[  0, 94,255],
	[  0, 88,255],[  0, 83,255],[  0, 78,255],[  0, 67,255],[  0, 62,255],
	[  0, 56,255],[  0, 51,255],[  0, 45,255],[  0, 40,255],[  0, 35,255],
	[  0, 29,255],[  0, 24,255],[  0, 18,255],[  0, 13,255],[  0,  8,255],
	[  0,  2,255],[  2,  0,255],[  7,  0,255],[ 18,  0,255],[ 24,  0,255],
	[ 29,  0,255],[ 34,  0,255],[ 40,  0,255],[ 45,  0,255],[ 50,  0,255],
	[ 56,  0,255],[ 61,  0,255],[ 67,  0,255],[ 72,  0,255],[ 77,  0,255],
	[ 83,  0,255],[ 88,  0,255],[ 93,  0,255],[104,  0,255],[110,  0,255],
	[115,  0,255],[120,  0,255],[126,  0,255],[131,  0,255],[136,  0,255],
	[142,  0,255],[147,  0,255],[153,  0,255],[158,  0,255],[163,  0,255],
	[169,  0,255],[174,  0,255],[180,  0,255],[190,  0,255],[196,  0,255],
	[201,  0,255],[206,  0,255],[212,  0,255],[217,  0,255],[223,  0,255],
	[228,  0,255],[233,  0,255],[239,  0,255],[244,  0,255],[249,  0,255],
	[255,  0,254],[255,  0,249],[255,  0,243],[255,  0,233],[255,  0,227],
	[255,  0,222],[255,  0,217],[255,  0,211],[255,  0,206],[255,  0,201]
			    ]
		 );

# Returns a hash: gradient-name => color-count
sub available_gradients {
  return map { $_, scalar( @{ $_gradients{$_} } ) } keys %_gradients;
}

# Returns array-ref of rgb-triples, undef if gradient-name not found
sub gradient {
  my ( $name ) = @_;

  unless( exists $_gradients{ $name } ) { return; }

  return $_gradients{$name};
}

# Returns the color corresponding to the position in the gradient given by f.
# Returns undef when gradient not found or f outside valid range.
sub grad2rgb {
  my ( $name, $frac ) = @_;

  unless( exists $_gradients{ $name } ) { return; }
  if( $frac < 0.0 || $frac >= 1.0 ) { return; }

  my $idx = int( $frac * scalar( @{$_gradients{$name}} ) );
  return _fmt( @{ $_gradients{$name}[$idx] } );
}

# Expects a gradient and and array-ref to an array of rgb triples.
# If the name already exists, the function returns the old array; undef otherws
sub register_gradient {
  my ( $name, $array_ref ) = @_;

  if( exists $_gradients{ $name } ) {
    my $old = $_gradients{ $name };
    $_gradients{ $name } = $array_ref;
    return $old;
  }

  $_gradients{ $name } = $array_ref;
  return undef;
}

} # end BEGIN (Gradients)

# ==================================================
# Names

BEGIN {

my $_default_namespace = 'x11';

my %_colors = (
  'www:aqua'    => [  0,255,255],'www:black'   => [  0,  0,  0],
  'www:blue'    => [  0,  0,255],'www:fuchsia' => [255,  0,255],
  'www:gray'    => [190,190,190],'www:green'   => [  0,128,  0],
  'www:lime'    => [  0,255,  0],'www:maroon'  => [128,  0,  0],
  'www:navy'    => [  0,  0,128],'www:olive'   => [128,128,  0],
  'www:purple'  => [128,  0,128],'www:red'     => [255,  0,  0],
  'www:silver'  => [192,192,192],'www:teal'    => [  0,128,128],
  'www:white'   => [255,255,255],'www:yellow'  => [255,255,  0],
  'www:orange'  => [255,165,  0],

'svg:palevioletred' => [219,112,147],'svg:mediumslateblue' => [123,104,238],
'svg:gold' => [255,215,0],'svg:gainsboro' => [220,220,220],
'svg:yellow' => [255,255,0],'svg:limegreen' => [50,205,50],
'svg:lightgoldenrodyellow' => [250,250,210],'svg:lavenderblush' => [255,240,245],
'svg:darkmagenta' => [139,0,139],'svg:darkgrey' => [169,169,169],
'svg:blanchedalmond' => [255,235,205],'svg:ghostwhite' => [248,248,255],
'svg:floralwhite' => [255,250,240],'svg:coral' => [255,127,80],
'svg:honeydew' => [240,255,240],'svg:mistyrose' => [255,228,225],
'svg:slateblue' => [106,90,205],'svg:goldenrod' => [218,165,32],
'svg:darkcyan' => [0,139,139],'svg:moccasin' => [255,228,181],
'svg:mediumvioletred' => [199,21,133],'svg:maroon' => [128,0,0],
'svg:lightpink' => [255,182,193],'svg:lightsalmon' => [255,160,122],
'svg:paleturquoise' => [175,238,238],'svg:darksalmon' => [233,150,122],
'svg:yellowgreen' => [154,205,50],'svg:mediumturquoise' => [72,209,204],
'svg:chartreuse' => [127,255,0],'svg:peru' => [205,133,63],
'svg:palegoldenrod' => [238,232,170],'svg:red' => [255,0,0],
'svg:lavender' => [230,230,250],'svg:lightseagreen' => [32,178,170],
'svg:powderblue' => [176,224,230],'svg:orchid' => [218,112,214],
'svg:cornsilk' => [255,248,220],'svg:seagreen' => [46,139,87],
'svg:royalblue' => [65,105,225],'svg:ivory' => [255,255,240],
'svg:tan' => [210,180,140],'svg:linen' => [250,240,230],
'svg:darkorchid' => [153,50,204],'svg:tomato' => [255,99,71],
'svg:lightcyan' => [224,255,255],'svg:darkolivegreen' => [85,107,47],
'svg:sienna' => [160,82,45],'svg:lightsteelblue' => [176,196,222],
'svg:indigo' => [75,0,130],'svg:peachpuff' => [255,218,185],
'svg:lime' => [0,255,0],'svg:mediumspringgreen' => [0,250,154],
'svg:silver' => [192,192,192],'svg:saddlebrown' => [139,69,19],
'svg:lightyellow' => [255,255,224],'svg:grey' => [128,128,128],
'svg:thistle' => [216,191,216],'svg:deepskyblue' => [0,191,255],
'svg:lightgreen' => [144,238,144],'svg:blueviolet' => [138,43,226],
'svg:aqua' => [0,255,255],'svg:cyan' => [0,255,255],
'svg:papayawhip' => [255,239,213],'svg:deeppink' => [255,20,147],
'svg:firebrick' => [178,34,34],'svg:navy' => [0,0,128],
'svg:hotpink' => [255,105,180],'svg:pink' => [255,192,203],
'svg:darkturquoise' => [0,206,209],'svg:navajowhite' => [255,222,173],
'svg:lightslategrey' => [119,136,153],'svg:lawngreen' => [124,252,0],
'svg:lightcoral' => [240,128,128],'svg:palegreen' => [152,251,152],
'svg:dodgerblue' => [30,144,255],'svg:greenyellow' => [173,255,47],
'svg:lightskyblue' => [135,206,250],'svg:brown' => [165,42,42],
'svg:dimgrey' => [105,105,105],'svg:aquamarine' => [127,255,212],
'svg:darkseagreen' => [143,188,143],'svg:fuchsia' => [255,0,255],
'svg:magenta' => [255,0,255],'svg:chocolate' => [210,105,30],
'svg:mediumseagreen' => [60,179,113],'svg:cadetblue' => [95,158,160],
'svg:purple' => [128,0,128],'svg:turquoise' => [64,224,208],
'svg:darkkhaki' => [189,183,107],'svg:antiquewhite' => [250,235,215],
'svg:skyblue' => [135,206,235],'svg:sandybrown' => [244,164,96],
'svg:mediumblue' => [0,0,205],'svg:steelblue' => [70,130,180],
'svg:indianred' => [205,92,92],'svg:khaki' => [240,230,140],
'svg:lightblue' => [173,216,230],'svg:green' => [0,128,0],
'svg:olive' => [128,128,0],'svg:mediumorchid' => [186,85,211],
'svg:blue' => [0,0,255],'svg:snow' => [255,250,250],
'svg:rosybrown' => [188,143,143],'svg:orange' => [255,165,0],
'svg:slategrey' => [112,128,144],'svg:darkorange' => [255,140,0],
'svg:violet' => [238,130,238],'svg:darkslategrey' => [47,79,79],
'svg:whitesmoke' => [245,245,245],'svg:burlywood' => [222,184,135],
'svg:darkgreen' => [0,100,0],'svg:lemonchiffon' => [255,250,205],
'svg:midnightblue' => [25,25,112],'svg:mintcream' => [245,255,250],
'svg:oldlace' => [253,245,230],'svg:black' => [0,0,0],
'svg:bisque' => [255,228,196],'svg:mediumaquamarine' => [102,205,170],
'svg:olivedrab' => [107,142,35],'svg:salmon' => [250,128,114],
'svg:teal' => [0,128,128],'svg:seashell' => [255,245,238],
'svg:springgreen' => [0,255,127],'svg:plum' => [221,160,221],
'svg:darkviolet' => [148,0,211],'svg:wheat' => [245,222,179],
'svg:mediumpurple' => [147,112,219],'svg:cornflowerblue' => [100,149,237],
'svg:forestgreen' => [34,139,34],'svg:darkgoldenrod' => [184,134,11],
'svg:aliceblue' => [240,248,255],'svg:white' => [255,255,255],
'svg:darkblue' => [0,0,139],'svg:azure' => [240,255,255],
'svg:darkred' => [139,0,0],'svg:orangered' => [255,69,0],
'svg:darkslateblue' => [72,61,139],'svg:crimson' => [220,20,60],
'svg:lightgrey' => [211,211,211],'svg:beige' => [245,245,220],

'x11:deepskyblue3' => [0,154,205],'x11:gold' => [255,215,0],
'x11:gold1' => [255,215,0],'x11:mediumpurple3' => [137,104,205],
'x11:royalblue3' => [58,95,205],'x11:lightgoldenrodyellow' => [250,250,210],
'x11:lavenderblush' => [255,240,245],'x11:lavenderblush1' => [255,240,245],
'x11:pink1' => [255,181,197],'x11:green3' => [0,205,0],
'x11:lightsteelblue1' => [202,225,255],'x11:blanchedalmond' => [255,235,205],
'x11:salmon1' => [255,140,105],'x11:ghostwhite' => [248,248,255],
'x11:floralwhite' => [255,250,240],'x11:dodgerblue4' => [16,78,139],
'x11:grey43' => [110,110,110],'x11:indianred4' => [139,58,58],
'x11:mistyrose1' => [255,228,225],'x11:mistyrose' => [255,228,225],
'x11:dodgerblue2' => [28,134,238],'x11:grey37' => [94,94,94],
'x11:grey9' => [23,23,23],'x11:purple4' => [85,26,139],
'x11:orchid2' => [238,122,233],'x11:cornsilk3' => [205,200,177],
'x11:goldenrod' => [218,165,32],'x11:hotpink4' => [139,58,98],
'x11:lightpink' => [255,182,193],'x11:coral2' => [238,106,80],
'x11:cyan2' => [0,238,238],'x11:grey87' => [222,222,222],
'x11:grey91' => [232,232,232],'x11:violetred4' => [139,34,82],
'x11:violetred2' => [238,58,140],'x11:indianred2' => [238,99,99],
'x11:lightyellow3' => [205,205,180],'x11:darkolivegreen2' => [188,238,104],
'x11:magenta3' => [205,0,205],'x11:grey64' => [163,163,163],
'x11:honeydew3' => [193,205,193],'x11:lightsalmon3' => [205,129,98],
'x11:springgreen4' => [0,139,69],'x11:grey57' => [145,145,145],
'x11:grey50' => [127,127,127],'x11:grey66' => [168,168,168],
'x11:antiquewhite1' => [255,239,219],'x11:paleturquoise' => [175,238,238],
'x11:navajowhite2' => [238,207,161],'x11:lightpink3' => [205,140,149],
'x11:darksalmon' => [233,150,122],'x11:grey52' => [133,133,133],
'x11:slategrey3' => [159,182,205],'x11:darkseagreen4' => [105,139,105],
'x11:chartreuse' => [127,255,0],'x11:chartreuse1' => [127,255,0],
'x11:grey42' => [107,107,107],'x11:peru' => [205,133,63],
'x11:tan3' => [205,133,63],'x11:grey19' => [48,48,48],
'x11:palegreen3' => [124,205,124],'x11:lavender' => [230,230,250],
'x11:red3' => [205,0,0],'x11:orchid' => [218,112,214],
'x11:powderblue' => [176,224,230],'x11:grey35' => [89,89,89],
'x11:plum4' => [139,102,139],'x11:cornsilk' => [255,248,220],
'x11:cornsilk1' => [255,248,220],'x11:royalblue' => [65,105,225],
'x11:darkgoldenrod2' => [238,173,14],'x11:lightpink4' => [139,95,101],
'x11:springgreen2' => [0,238,118],'x11:tan' => [210,180,140],
'x11:lightslateblue' => [132,112,255],'x11:darkorchid' => [153,50,204],
'x11:orangered2' => [238,64,0],'x11:palevioletred1' => [255,130,171],
'x11:grey63' => [161,161,161],'x11:maroon2' => [238,48,167],
'x11:blue2' => [0,0,238],'x11:turquoise4' => [0,134,139],
'x11:lightcyan1' => [224,255,255],'x11:lightcyan' => [224,255,255],
'x11:springgreen3' => [0,205,102],'x11:darkorchid4' => [104,34,139],
'x11:sienna' => [160,82,45],'x11:goldenrod2' => [238,180,34],
'x11:lightgoldenrod3' => [205,190,112],'x11:green' => [0,255,0],
'x11:green1' => [0,255,0],'x11:peachpuff1' => [255,218,185],
'x11:peachpuff' => [255,218,185],'x11:yellow3' => [205,205,0],
'x11:mediumspringgreen' => [0,250,154],'x11:cadetblue3' => [122,197,205],
'x11:royalblue1' => [72,118,255],'x11:deepskyblue1' => [0,191,255],
'x11:deepskyblue' => [0,191,255],'x11:firebrick1' => [255,48,48],
'x11:grey80' => [204,204,204],'x11:grey28' => [71,71,71],
'x11:palegreen2' => [144,238,144],'x11:lightgreen' => [144,238,144],
'x11:blueviolet' => [138,43,226],'x11:deeppink1' => [255,20,147],
'x11:deeppink' => [255,20,147],'x11:deeppink2' => [238,18,137],
'x11:lightskyblue2' => [164,211,238],'x11:grey77' => [196,196,196],
'x11:grey72' => [184,184,184],'x11:tomato2' => [238,92,66],
'x11:steelblue2' => [92,172,238],'x11:hotpink' => [255,105,180],
'x11:slateblue4' => [71,60,139],'x11:pink' => [255,192,203],
'x11:darkturquoise' => [0,206,209],'x11:antiquewhite3' => [205,192,176],
'x11:grey32' => [82,82,82],'x11:lightyellow2' => [238,238,209],
'x11:olivedrab4' => [105,139,34],'x11:lightblue4' => [104,131,139],
'x11:royalblue2' => [67,110,238],'x11:navajowhite1' => [255,222,173],
'x11:navajowhite' => [255,222,173],'x11:lightgoldenrod' => [238,221,130],
'x11:grey85' => [217,217,217],'x11:maroon4' => [139,28,98],
'x11:grey90' => [229,229,229],'x11:grey17' => [43,43,43],
'x11:seashell4' => [139,134,130],'x11:greenyellow' => [173,255,47],
'x11:dodgerblue1' => [30,144,255],'x11:dodgerblue' => [30,144,255],
'x11:grey89' => [227,227,227],'x11:brown2' => [238,59,59],
'x11:paleturquoise2' => [174,238,238],'x11:lightskyblue' => [135,206,250],
'x11:salmon4' => [139,76,57],'x11:chocolate3' => [205,102,29],
'x11:grey70' => [179,179,179],'x11:grey25' => [64,64,64],
'x11:darkolivegreen4' => [110,139,61],'x11:mediumorchid2' => [209,95,238],
'x11:brown' => [165,42,42],'x11:grey67' => [171,171,171],
'x11:grey41' => [105,105,105],'x11:dimgrey' => [105,105,105],
'x11:grey60' => [153,153,153],'x11:indianred3' => [205,85,85],
'x11:chocolate' => [210,105,30],'x11:darkslategrey1' => [151,255,255],
'x11:grey2' => [5,5,5],'x11:firebrick3' => [205,38,38],
'x11:snow4' => [139,137,137],'x11:mediumseagreen' => [60,179,113],
'x11:darkorchid1' => [191,62,255],'x11:pink3' => [205,145,158],
'x11:violetred1' => [255,62,150],'x11:grey83' => [212,212,212],
'x11:olivedrab1' => [192,255,62],'x11:darkkhaki' => [189,183,107],
'x11:deepskyblue4' => [0,104,139],'x11:darkorchid2' => [178,58,238],
'x11:skyblue' => [135,206,235],'x11:mediumorchid3' => [180,82,205],
'x11:rosybrown4' => [139,105,105],'x11:grey16' => [41,41,41],
'x11:yellow4' => [139,139,0],'x11:maroon' => [176,48,96],
'x11:turquoise2' => [0,229,238],'x11:mistyrose2' => [238,213,210],
'x11:blue3' => [0,0,205],'x11:mediumblue' => [0,0,205],
'x11:grey4' => [10,10,10],'x11:pink2' => [238,169,184],
'x11:chocolate2' => [238,118,33],'x11:lightyellow4' => [139,139,122],
'x11:grey99' => [252,252,252],'x11:red2' => [238,0,0],
'x11:tan4' => [139,90,43],'x11:yellow2' => [238,238,0],
'x11:grey12' => [31,31,31],'x11:deeppink4' => [139,10,80],
'x11:lightsalmon4' => [139,87,66],'x11:lightcyan4' => [122,139,139],
'x11:snow1' => [255,250,250],'x11:snow' => [255,250,250],
'x11:brown4' => [139,35,35],'x11:darkseagreen2' => [180,238,180],
'x11:lightsteelblue2' => [188,210,238],'x11:rosybrown' => [188,143,143],
'x11:maroon1' => [255,52,179],'x11:slategrey' => [112,128,144],
'x11:orange' => [255,165,0],'x11:orange1' => [255,165,0],
'x11:orangered3' => [205,55,0],'x11:plum3' => [205,150,205],
'x11:turquoise3' => [0,197,205],'x11:pink4' => [139,99,108],
'x11:violet' => [238,130,238],'x11:grey96' => [245,245,245],
'x11:whitesmoke' => [245,245,245],'x11:lightgoldenrod1' => [255,236,139],
'x11:darkorange1' => [255,127,0],'x11:seashell2' => [238,229,222],
'x11:midnightblue' => [25,25,112],'x11:grey27' => [69,69,69],
'x11:mediumpurple2' => [159,121,238],'x11:bisque4' => [139,125,107],
'x11:black' => [0,0,0],'x11:grey0' => [0,0,0],
'x11:lavenderblush4' => [139,131,134],'x11:bisque1' => [255,228,196],
'x11:bisque' => [255,228,196],'x11:mediumaquamarine' => [102,205,170],
'x11:aquamarine3' => [102,205,170],'x11:goldenrod1' => [255,193,37],
'x11:green4' => [0,139,0],'x11:bisque3' => [205,183,158],
'x11:salmon' => [250,128,114],'x11:grey1' => [3,3,3],
'x11:purple3' => [125,38,205],'x11:khaki4' => [139,134,78],
'x11:grey' => [190,190,190],'x11:cadetblue4' => [83,134,139],
'x11:cadetblue1' => [152,245,255],'x11:hotpink3' => [205,96,144],
'x11:antiquewhite2' => [238,223,204],'x11:darkorange4' => [139,69,0],
'x11:cornsilk2' => [238,232,205],'x11:grey93' => [237,237,237],
'x11:thistle3' => [205,181,205],'x11:plum2' => [238,174,238],
'x11:burlywood2' => [238,197,145],'x11:skyblue4' => [74,112,139],
'x11:peachpuff2' => [238,203,173],'x11:grey62' => [158,158,158],
'x11:paleturquoise3' => [150,205,205],'x11:lightblue1' => [191,239,255],
'x11:mediumpurple' => [147,112,219],'x11:peachpuff3' => [205,175,149],
'x11:grey49' => [125,125,125],'x11:grey3' => [8,8,8],
'x11:steelblue1' => [99,184,255],'x11:grey73' => [186,186,186],
'x11:grey44' => [112,112,112],'x11:palevioletred4' => [139,71,93],
'x11:khaki2' => [238,230,133],'x11:gold3' => [205,173,0],
'x11:grey47' => [120,120,120],'x11:aliceblue' => [240,248,255],
'x11:grey58' => [148,148,148],'x11:darkslategrey4' => [82,139,139],
'x11:mediumorchid4' => [122,55,139],'x11:thistle1' => [255,225,255],
'x11:mistyrose4' => [139,125,123],'x11:orchid1' => [255,131,250],
'x11:hotpink2' => [238,106,167],'x11:azure' => [240,255,255],
'x11:azure1' => [240,255,255],'x11:darkred' => [139,0,0],
'x11:red4' => [139,0,0],'x11:chartreuse2' => [118,238,0],
'x11:slateblue1' => [131,111,255],'x11:grey15' => [38,38,38],
'x11:grey71' => [181,181,181],'x11:darkslategrey2' => [141,238,238],
'x11:snow3' => [205,201,201],'x11:bisque2' => [238,213,183],
'x11:darkslateblue' => [72,61,139],'x11:coral4' => [139,62,47],
'x11:grey69' => [176,176,176],'x11:burlywood4' => [139,115,85],
'x11:coral3' => [205,91,69],'x11:purple' => [160,32,240],
'x11:grey36' => [92,92,92],'x11:grey94' => [240,240,240],
'x11:palevioletred2' => [238,121,159],'x11:grey46' => [117,117,117],
'x11:palevioletred' => [219,112,147],'x11:mediumslateblue' => [123,104,238],
'x11:seagreen1' => [84,255,159],'x11:gainsboro' => [220,220,220],
'x11:yellow1' => [255,255,0],'x11:yellow' => [255,255,0],
'x11:limegreen' => [50,205,50],'x11:darkgrey' => [169,169,169],
'x11:darkmagenta' => [139,0,139],'x11:magenta4' => [139,0,139],
'x11:grey59' => [150,150,150],'x11:firebrick2' => [238,44,44],
'x11:coral' => [255,127,80],'x11:honeydew' => [240,255,240],
'x11:honeydew1' => [240,255,240],'x11:grey86' => [219,219,219],
'x11:grey13' => [33,33,33],'x11:purple1' => [155,48,255],
'x11:grey82' => [209,209,209],'x11:grey65' => [166,166,166],
'x11:grey97' => [247,247,247],'x11:azure4' => [131,139,139],
'x11:darkslategrey3' => [121,205,205],'x11:lightcyan3' => [180,205,205],
'x11:aquamarine2' => [118,238,198],'x11:grey92' => [235,235,235],
'x11:slateblue' => [106,90,205],'x11:darkcyan' => [0,139,139],
'x11:cyan4' => [0,139,139],'x11:chartreuse3' => [102,205,0],
'x11:moccasin' => [255,228,181],'x11:mediumvioletred' => [199,21,133],
'x11:tomato3' => [205,79,57],'x11:grey31' => [79,79,79],
'x11:sienna2' => [238,121,66],'x11:grey98' => [250,250,250],
'x11:gold4' => [139,117,0],'x11:slateblue3' => [105,89,205],
'x11:grey14' => [36,36,36],'x11:honeydew4' => [131,139,131],
'x11:grey61' => [156,156,156],'x11:violetred3' => [205,50,120],
'x11:grey39' => [99,99,99],'x11:aquamarine4' => [69,139,116],
'x11:darkgoldenrod4' => [139,101,8],'x11:mediumpurple1' => [171,130,255],
'x11:lightsalmon1' => [255,160,122],'x11:lightsalmon' => [255,160,122],
'x11:darkolivegreen3' => [162,205,90],'x11:grey10' => [26,26,26],
'x11:khaki3' => [205,198,115],'x11:navajowhite3' => [205,179,139],
'x11:lightpink1' => [255,174,185],'x11:grey81' => [207,207,207],
'x11:grey45' => [115,115,115],'x11:wheat3' => [205,186,150],
'x11:steelblue4' => [54,100,139],'x11:grey48' => [122,122,122],
'x11:olivedrab3' => [154,205,50],'x11:yellowgreen' => [154,205,50],
'x11:mediumturquoise' => [72,209,204],'x11:palegoldenrod' => [238,232,170],
'x11:ivory2' => [238,238,224],'x11:darkolivegreen1' => [202,255,112],
'x11:red1' => [255,0,0],'x11:red' => [255,0,0],
'x11:lemonchiffon4' => [139,137,112],'x11:lightseagreen' => [32,178,170],
'x11:seagreen4' => [46,139,87],'x11:seagreen' => [46,139,87],
'x11:ivory' => [255,255,240],'x11:ivory1' => [255,255,240],
'x11:linen' => [250,240,230],'x11:grey34' => [87,87,87],
'x11:thistle2' => [238,210,238],'x11:tomato' => [255,99,71],
'x11:tomato1' => [255,99,71],'x11:slategrey1' => [198,226,255],
'x11:orchid3' => [205,105,201],'x11:lightcyan2' => [209,238,238],
'x11:grey54' => [138,138,138],'x11:darkolivegreen' => [85,107,47],
'x11:lightsteelblue' => [176,196,222],'x11:grey33' => [84,84,84],
'x11:chocolate4' => [139,69,19],'x11:saddlebrown' => [139,69,19],
'x11:orange3' => [205,133,0],'x11:lightyellow' => [255,255,224],
'x11:lightyellow1' => [255,255,224],'x11:grey75' => [191,191,191],
'x11:khaki1' => [255,246,143],'x11:thistle' => [216,191,216],
'x11:grey79' => [201,201,201],'x11:plum1' => [255,187,255],
'x11:paleturquoise4' => [102,139,139],'x11:cyan1' => [0,255,255],
'x11:cyan' => [0,255,255],'x11:maroon3' => [205,41,144],
'x11:papayawhip' => [255,239,213],'x11:seagreen3' => [67,205,128],
'x11:lightgoldenrod4' => [139,129,76],'x11:lightskyblue1' => [176,226,255],
'x11:firebrick' => [178,34,34],'x11:grey30' => [77,77,77],
'x11:grey26' => [66,66,66],'x11:antiquewhite4' => [139,131,120],
'x11:navyblue' => [0,0,128],'x11:navy' => [0,0,128],
'x11:grey7' => [18,18,18],'x11:grey5' => [13,13,13],
'x11:grey29' => [74,74,74],'x11:turquoise1' => [0,245,255],
'x11:darkgoldenrod3' => [205,149,12],'x11:goldenrod4' => [139,105,20],
'x11:palevioletred3' => [205,104,137],'x11:lightslategrey' => [119,136,153],
'x11:snow2' => [238,233,233],'x11:grey24' => [61,61,61],
'x11:slategrey4' => [108,123,139],'x11:grey55' => [140,140,140],
'x11:seashell3' => [205,197,191],'x11:deeppink3' => [205,16,118],
'x11:lawngreen' => [124,252,0],'x11:darkorchid3' => [154,50,205],
'x11:lightcoral' => [240,128,128],'x11:palegreen' => [152,251,152],
'x11:grey56' => [143,143,143],'x11:grey23' => [59,59,59],
'x11:grey74' => [189,189,189],'x11:azure2' => [224,238,238],
'x11:darkseagreen3' => [155,205,155],'x11:grey20' => [51,51,51],
'x11:cadetblue2' => [142,229,238],'x11:grey84' => [214,214,214],
'x11:cornsilk4' => [139,136,120],'x11:grey38' => [97,97,97],
'x11:magenta1' => [255,0,255],'x11:magenta' => [255,0,255],
'x11:darkseagreen' => [143,188,143],'x11:aquamarine1' => [127,255,212],
'x11:aquamarine' => [127,255,212],'x11:lightblue3' => [154,192,205],
'x11:olivedrab2' => [179,238,58],'x11:grey40' => [102,102,102],
'x11:peachpuff4' => [139,119,101],'x11:paleturquoise1' => [187,255,255],
'x11:darkseagreen1' => [193,255,193],'x11:darkorange3' => [205,102,0],
'x11:brown3' => [205,51,51],'x11:grey51' => [130,130,130],
'x11:mediumpurple4' => [93,71,139],'x11:lightpink2' => [238,162,173],
'x11:cadetblue' => [95,158,160],'x11:lemonchiffon2' => [238,233,191],
'x11:green2' => [0,238,0],'x11:azure3' => [193,205,205],
'x11:turquoise' => [64,224,208],'x11:brown1' => [255,64,64],
'x11:lightsteelblue4' => [110,123,139],'x11:orange2' => [238,154,0],
'x11:antiquewhite' => [250,235,215],'x11:wheat2' => [238,216,174],
'x11:rosybrown2' => [238,180,180],'x11:lightsteelblue3' => [162,181,205],
'x11:grey78' => [199,199,199],'x11:grey21' => [54,54,54],
'x11:sandybrown' => [244,164,96],'x11:lavenderblush2' => [238,224,229],
'x11:steelblue' => [70,130,180],'x11:grey95' => [242,242,242],
'x11:indianred' => [205,92,92],'x11:skyblue1' => [135,206,255],
'x11:khaki' => [240,230,140],'x11:orchid4' => [139,71,137],
'x11:chocolate1' => [255,127,36],'x11:goldenrod3' => [205,155,29],
'x11:sienna4' => [139,71,38],'x11:lightblue' => [173,216,230],
'x11:grey88' => [224,224,224],'x11:palegreen4' => [84,139,84],
'x11:mediumorchid' => [186,85,211],'x11:blue' => [0,0,255],
'x11:blue1' => [0,0,255],'x11:dodgerblue3' => [24,116,205],
'x11:indianred1' => [255,106,106],'x11:cyan3' => [0,205,205],
'x11:tan1' => [255,165,79],'x11:darkorange' => [255,140,0],
'x11:skyblue2' => [126,192,238],'x11:coral1' => [255,114,86],
'x11:darkslategrey' => [47,79,79],'x11:burlywood' => [222,184,135],
'x11:sienna3' => [205,104,57],'x11:darkgreen' => [0,100,0],
'x11:mistyrose3' => [205,183,181],'x11:grey68' => [173,173,173],
'x11:grey53' => [135,135,135],'x11:lemonchiffon' => [255,250,205],
'x11:lemonchiffon1' => [255,250,205],'x11:palegreen1' => [154,255,154],
'x11:grey76' => [194,194,194],'x11:steelblue3' => [79,148,205],
'x11:grey11' => [28,28,28],'x11:oldlace' => [253,245,230],
'x11:mintcream' => [245,255,250],'x11:firebrick4' => [139,26,26],
'x11:lemonchiffon3' => [205,201,165],'x11:olivedrab' => [107,142,35],
'x11:honeydew2' => [224,238,224],'x11:deepskyblue2' => [0,178,238],
'x11:slateblue2' => [122,103,238],'x11:slategrey2' => [185,211,238],
'x11:seagreen2' => [78,238,148],'x11:salmon2' => [238,130,98],
'x11:ivory3' => [205,205,193],'x11:mediumorchid1' => [224,102,255],
'x11:tan2' => [238,154,73],'x11:springgreen' => [0,255,127],
'x11:springgreen1' => [0,255,127],'x11:seashell1' => [255,245,238],
'x11:seashell' => [255,245,238],'x11:skyblue3' => [108,166,205],
'x11:chartreuse4' => [69,139,0],'x11:burlywood3' => [205,170,125],
'x11:plum' => [221,160,221],'x11:ivory4' => [139,139,131],
'x11:darkviolet' => [148,0,211],'x11:lightblue2' => [178,223,238],
'x11:wheat' => [245,222,179],'x11:darkgoldenrod1' => [255,185,15],
'x11:cornflowerblue' => [100,149,237],'x11:purple2' => [145,44,238],
'x11:grey6' => [15,15,15],'x11:magenta2' => [238,0,238],
'x11:sienna1' => [255,130,71],'x11:darkgoldenrod' => [184,134,11],
'x11:forestgreen' => [34,139,34],'x11:navajowhite4' => [139,121,94],
'x11:royalblue4' => [39,64,139],'x11:wheat1' => [255,231,186],
'x11:lightskyblue4' => [96,123,139],'x11:grey18' => [46,46,46],
'x11:orangered4' => [139,37,0],'x11:salmon3' => [205,112,84],
'x11:white' => [255,255,255],'x11:grey100' => [255,255,255],
'x11:orange4' => [139,90,0],'x11:wheat4' => [139,126,102],
'x11:rosybrown1' => [255,193,193],'x11:grey8' => [20,20,20],
'x11:lightgoldenrod2' => [238,220,130],'x11:lightskyblue3' => [141,182,205],
'x11:violetred' => [208,32,144],'x11:blue4' => [0,0,139],
'x11:darkblue' => [0,0,139],'x11:lavenderblush3' => [205,193,197],
'x11:thistle4' => [139,123,139],'x11:hotpink1' => [255,110,180],
'x11:darkorange2' => [238,118,0],'x11:lightsalmon2' => [238,149,114],
'x11:orangered1' => [255,69,0],'x11:orangered' => [255,69,0],
'x11:burlywood1' => [255,211,155],'x11:lightgrey' => [211,211,211],
'x11:grey22' => [56,56,56],'x11:tomato4' => [139,54,38],
'x11:rosybrown3' => [205,155,155],'x11:gold2' => [238,201,0],
'x11:beige' => [245,245,220]
	      );

# Returns a hash-ref: color-name => RGB triple
sub available_names {
  return \%_colors;
}

# Returns the RGB triple for a name, undef if name not found
# The name is normalized before lookup is attempted. Normalization consists
# of: lowercasing and elimination of whitespace. Also, "gray" is replaced 
# with "grey".
# If the name is prefixed with a namespace (separated by colon ':'),
# only this namespace is searched. If no namespace is specified, then
# the lookup occurs first in the global namespace, then in the default
# namespace.

sub name2rgb {
  my ( $name ) = @_;

  my ( $ns, $core, $norm ) = _normalize_name( $name );

  # If explicit namespace:
  if( $ns ne '' ) {
    if( exists $_colors{ $norm } ) {
      return _fmt( @{ $_colors{ $norm } } );
    } else {
      return; # Do not search further if explicit namespace is given
    }
  }

  # No explicit namespace
  if( exists $_colors{ $core } ) {
    return _fmt( @{ $_colors{ $core } } ); # global namespace
  }

  # No namespace, but ':' prefix: search global ONLY, but not default ns
  if( $core ne $norm ) { return; }

  $norm = get_default_namespace() . ':' . $core;
  if( exists $_colors{ $norm } ) {
    return _fmt( @{ $_colors{ $norm } } ); # default namespace
  }

  # Not found
  return;
}

# Takes a name and an RGB triple. Registers the triple for the given name.
# The name will be normalized (lowercased, whitespace eliminated, 'gray' 
# replaced by 'grey') before assignment is made.
# If the name is not prefixed by a namespace, the color will be entered 
# into the global namespace. 
# Returns the old value for the name, if the name already exists.

sub register_name {
  my ( $name, $r, $g, $b ) = @_;

  my ( $ns, $core, $norm ) = _normalize_name( $name );

  # If no explicit ns is given, lookup and replace for $core, which is
  # guaranteed not preceeded by ':'. Otherwise, use fully qualified name.
  my $crr = ( $ns eq '' ) ? $core : $norm;

  if( exists $_colors{ $crr } ) {
    my $old = $_colors{ $crr };
    $_colors{ $crr } = [ $r, $g, $b ];

    return _fmt( @$old );
  }

  $_colors{ $crr } = [ $r, $g, $b ];

  return;
}

sub _normalize_name {
  my ( $name ) = @_;

  $name = lc( $name );   # Lowercase
  $name =~ s/\s//g;      # Eliminate whitespace
  $name =~ s/gray/grey/; # gray -> grey

  my ( $ns, $core ) = ( '', $name );
  if( $name =~ /:/ ) {
    ( $ns, $core ) = split ':', $name;
  }

  return ( $ns, $core, $name );
}

# Sets the default namespace. Returns the previous value.
# Giving an empty string as argument makes the global namespace the default.
# Note that the global namespace is initially EMPTY!

sub set_default_namespace {
  my $old = $_default_namespace;
  $_default_namespace = $_[0];
  return $old;
}

sub get_default_namespace {
  return $_default_namespace;
}

} # end BEGIN (Names)



1;
__END__


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