File Coverage

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

Criterion	Covered	Total	%
statement	34	34	100.0
branch	21	30	70.0
condition			n/a
subroutine	5	5	100.0
pod	0	2	0.0
total	60	71	84.5

# HWB color space specific code

package Graphics::Toolkit::Color::Space::Instance::HWB;
use v5.12;
use warnings;
use Graphics::Toolkit::Color::Space qw/min max/;

 # add constraint W + B <= 100

sub from_rgb {
    my ($r, $g, $b) = @{$_[0]};
    my $vmax = max($r, $g, $b);
    my $white = my $vmin = min($r, $g, $b);
    return ([0,1,0]) if $white == 1;
    my $black = 1 - ($vmax);
    return ([0,0,1]) if $black == 1;

    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, $b) = @{$_[0]};
    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);
    return \@rgb;
}

Graphics::Toolkit::Color::Space->new(
            axis => [qw/hue whiteness blackness/],
           range => [360, 100, 100],
       precision => 0,
            type => [qw/angular linear linear/],
          suffix => ['', '%', '%'],
      constraint => {cone => {checker => '$_[0][1] + $_[0][2] <= 1',
		                     error    => 'The sum of whiteness and blackness can not exceed 100%.',
		                     remedy   => 'my $s = $_[0][1] + $_[0][2];[$_[0][0], $_[0][1]/$s, $_[0][2]/$s]', }},

         convert => {RGB => [\&to_rgb, \&from_rgb]},
);