use warnings;
use List::Util qw( min max );
-our $VERSION = '1.01';
+our $VERSION = '1.02';
# ITU-R recommendation 601 luma co-efficients
our $kr = .299;
our $kb = .114;
our $kg = 1 - $kb - $kr;
+my $PI = 2 * atan2 1, 0;
+
sub new {
my $class = shift;
my @rgb = @_ >= 3 ? @_ : (map {hex} $_[0] =~ /(..)/g);
return $r*$kr + $g*$kg + $b*$kb;
}
+sub hue {
+ my ($r, $g, $b) = @{ $_[0] };
+ my $hue = atan2 sqrt(3) * ($g - $b), $r*2 - $g - $b;
+ return ($hue + $PI) / $PI / 2; # 0 .. 1
+}
+
sub rgb24 {
my $str = '';
$str .= sprintf '%X', min($_ / 17 + .5, 15) for @{ $_[0] };
<div class="section">
<:
-use Shiar_Sheet::Colour '1.01';
+use Shiar_Sheet::Colour '1.02';
+use List::Util qw( min max );
sub colcell {
- my $name = shift;
+ my $name = shift or return "<td colspan=3>\n";
my $col = Shiar_Sheet::Colour->new(@_);
my $minhex = $col->rgb24;
my $css = '#' . $col->rgb48;
<div class="section">
<h2>256-colour space</h2>
<:
+my @colmap; # saturation => value => hue => colcell
for my $r (0 .. 5) {
- print '<table>';
for my $g (0 .. 5) {
- print '<tr>';
for my $b (0 .. 5) {
my $index = $r*6*6 + $g*6 + $b + 16;
- print colcell($index, map { $_ && $_*40 + 55 } $r, $g, $b);
+ my @rgb = map { $_ && $_*40 + 55 } $r, $g, $b;
+
+ my $h = Shiar_Sheet::Colour->new(@rgb)->hue * 35;
+ my $v = int(max(@rgb) / 255 * 5);
+ my $s = abs(min(@rgb) - max(@rgb)) / 255 * 7;
+ my $grey = !$s;
+
+ $h-- for grep {$h >= $_} 4, 6, 16, 19, 28, 31;
+ $v = 5 - $v;
+ $s = 7 - $s - $v;
+ $s-- if $s;
+
+ if ($grey) {
+ $h = 30; # greyscale hue
+ $s -= 2; # lowest saturation for other hues
+ $v = $s = 0 if $s < 0; # black at full saturation
+ }
+
+ $colmap[$s][$v][$h] = [$index, @rgb];
}
}
+}
+
+{
+ print '<table>';
+ for my $h (0 .. 30) {
+ print '<tr>';
+ print colcell(@$_) for map { $_->[$h] } map { @{$_} } @colmap;
+ }
print "</table>\n";
}
print "\n";