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termcol: amstrad cpc palette (27-colour hsv)
[sheet.git]
/
Shiar_Sheet
/
Colour.pm
diff --git
a/Shiar_Sheet/Colour.pm
b/Shiar_Sheet/Colour.pm
index 7ea68e9dcf63bd3874facf8e8a89f068d52ba213..cdac0b346066b204e70fa148001c959ab74de43b 100644
(file)
--- a/
Shiar_Sheet/Colour.pm
+++ b/
Shiar_Sheet/Colour.pm
@@
-4,13
+4,15
@@
use strict;
use warnings;
use List::Util qw( min max );
use warnings;
use List::Util qw( min max );
-our $VERSION = '1.0
1
';
+our $VERSION = '1.0
3
';
# ITU-R recommendation 601 luma co-efficients
our $kr = .299;
our $kb = .114;
our $kg = 1 - $kb - $kr;
# 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);
sub new {
my $class = shift;
my @rgb = @_ >= 3 ? @_ : (map {hex} $_[0] =~ /(..)/g);
@@
-39,6
+41,15
@@
sub luminance {
return $r*$kr + $g*$kg + $b*$kb;
}
return $r*$kr + $g*$kg + $b*$kb;
}
+sub hue {
+ # colour shift (red = 0 .. 1)
+ my ($r, $g, $b) = @{ $_[0] };
+ my $hue = atan2 sqrt(3) * ($g - $b), $r*2 - $g - $b;
+ $hue /= $PI * 2; # -.5 .. .5
+ $hue++ if $hue < 0; # fp $hue %= 1
+ return $hue;
+}
+
sub rgb24 {
my $str = '';
$str .= sprintf '%X', min($_ / 17 + .5, 15) for @{ $_[0] };
sub rgb24 {
my $str = '';
$str .= sprintf '%X', min($_ / 17 + .5, 15) for @{ $_[0] };