my $vmax = $dim - 1;
my $smax = $dim - 1;
$rgbval ||= sub { join('', @_), map { int $_ * 255 / $vmax } @_ };
- $greyramp ||= [];
my %greymap; # name => value
my @colmap; # saturation => value => hue => [name, r,g,b]
my $s = abs(min(@rgb) - max(@rgb));
if (!$s) {
- my ($index, $l) = $rgbval->(@rgb);
- $greymap{$index} = $l;
- next;
+ if ($greyramp) {
+ my ($index, $l) = $rgbval->(@rgb);
+ $greymap{$index} = $l;
+ next;
+ }
+
+ $h = $hmax; # greyscale hue
+ $s = 1; # lowest saturation for other hues
+ $v = $s = $vmax if !$v; # black at full saturation
}
$v = $vmax - $v;
$out .= colcell(@$_) for map { $_->[$h] } map { @{$_} } @colmap;
}
- $offset += $dim ** 3;
- $greymap{$offset++} = $_ for @{$greyramp};
+ if ($greyramp) {
+ $offset += $dim ** 3;
+ $greymap{$offset++} = $_ for @{$greyramp};
+ }
- $out .= '<tbody>';
- my $col = 0;
- my $colbreak = scalar map { @$_ } @colmap; # same width as hue rows
- for my $num (sort { $greymap{$a} <=> $greymap{$b} } keys %greymap) {
- $out .= '<tr>' unless $col++ % $colbreak;
- $out .= colcell($num, ($greymap{$num}) x 3);
+ if (%greymap) {
+ $out .= '<tbody>';
+ my $col = 0;
+ my $colbreak = scalar map { @$_ } @colmap; # same width as hue rows
+ for my $num (sort { $greymap{$a} <=> $greymap{$b} } keys %greymap) {
+ $out .= '<tr>' unless $col++ % $colbreak;
+ $out .= colcell($num, ($greymap{$num}) x 3);
+ }
}
return $out;