added NCol color space

lib/Graphics/Toolkit/Color/Space/Instance/HWB.pm

@@ -9,7 +9,7 @@ use Graphics::Toolkit::Color::Space;
 
 my $hwb_def = Graphics::Toolkit::Color::Space->new( axis => [qw/hue whiteness blackness/],
                                                    range => [360, 100, 100],
-                                                    type => [qw/angular linear linear/]);
+                                                    type => [qw/angular linear linear/], );
 
    $hwb_def->add_converter('RGB', \&to_rgb, \&from_rgb );
 

lib/Graphics/Toolkit/Color/Space/Instance/NCol.pm

@@ -0,0 +1,87 @@
+use v5.12;
+use warnings;
+
+# HSL color space specific code
+
+package Graphics::Toolkit::Color::Space::Instance::NCol;
+use Graphics::Toolkit::Color::Space::Util ':all';
+use Graphics::Toolkit::Color::Space;
+
+my $hsl_def = Graphics::Toolkit::Color::Space->new( axis => [qw/hue whiteness blackness/],
+                                                   range => [ 360, 100, 100 ],  precision => 0
+                                                  suffix => ['', '%', '%'],
+                                                    type => [qw/no linear linear/],
+                                                    );
+
+   $hsl_def->add_converter('RGB', \&to_rgb, \&from_rgb );
+
+
+sub from_rgb {
+    my ($r, $g, $b) = @_;
+    my $vmax = max($r, $g, $b),
+    my $vmin = min($r, $g, $b);
+    my $l = ($vmax + $vmin) / 2;
+    return (0, 0, $l) if $vmax == $vmin;
+    my $d = $vmax - $vmin;
+    my $s = ($l > 0.5) ? ($d / (2 - $vmax - $vmin)) : ($d / ($vmax + $vmin));
+    my $h = ($vmax == $r) ? (($g - $b) / $d + ($g < $b ? 6 : 0)) :
+            ($vmax == $g) ? (($b - $r) / $d + 2)
+                          : (($r - $g) / $d + 4);
+    return ($h/6, $s, $l);
+}
+
+sub to_rgb {
+    my ($h, $s, $l) = @_;
+    $h *= 6;
+    my $C = $s * (1 - abs($l * 2 - 1));
+    my $X = $C * (1 - abs( rmod($h, 2) - 1) );
+    my $m = $l - ($C / 2);
+    return ($h < 1) ? ($C + $m, $X + $m,      $m)
+         : ($h < 2) ? ($X + $m, $C + $m,      $m)
+         : ($h < 3) ? (     $m, $C + $m, $X + $m)
+         : ($h < 4) ? (     $m, $X + $m, $C + $m)
+         : ($h < 5) ? ($X + $m,      $m, $C + $m)
+         :            ($C + $m,      $m, $X + $m);
+}
+
+$hsl_def;
+
+__END__
+
+sub from_rgb {
+    my ($r, $g, $b) = @_;
+    my $vmax = max($r, $g, $b);
+    my $white = my $vmin = min($r, $g, $b);
+    my $black = 1 - ($vmax);
+
+    my $d = $vmax - $vmin;
+    my $s = $d / $vmax;
+    my $h =     ($d == 0) ? 0 :
+            ($vmax == $r) ? (($g - $b) / $d + ($g < $b ? 6 : 0)) :
+            ($vmax == $g) ? (($b - $r) / $d + 2)
+                          : (($r - $g) / $d + 4);
+    return ($h/6, $white, $black);
+}
+
+
+sub to_rgb {
+    my ($h, $w, $b) = @_;
+    return (0, 0, 0) if $b == 1;
+    return (1, 1, 1) if $w == 1;
+    my $v = 1 - $b;
+    my $s = 1 - ($w / $v);
+    $s = 0 if $s < 0;
+    return ($v, $v, $v) if $s == 0;
+
+    my $hi = int( $h * 6 );
+    my $f = ( $h * 6 ) - $hi;
+    my $p = $v * (1 -  $s );
+    my $q = $v * (1 - ($s * $f));
+    my $t = $v * (1 - ($s * (1 - $f)));
+    my @rgb = ($hi == 1) ? ($q, $v, $p)
+            : ($hi == 2) ? ($p, $v, $t)
+            : ($hi == 3) ? ($p, $q, $v)
+            : ($hi == 4) ? ($t, $p, $v)
+            : ($hi == 5) ? ($v, $p, $q)
+            :              ($v, $t, $p);
+}