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1f72b051 MG |
1 | package Convert::Color::LUV; |
2 | ||
3 | use 5.014000; | |
4 | use strict; | |
5 | use warnings; | |
6 | use parent qw/Convert::Color/; | |
7 | ||
8 | use Convert::Color::XYZ; | |
9 | ||
10 | our $VERSION = '0.001'; | |
11 | ||
12 | use constant +{ ## no critic (Capitalization) | |
13 | KAPPA => 903.2962962, | |
14 | EPS => 0.0088564516, | |
15 | ||
16 | REF_U => 0.19783000664283, | |
17 | REF_V => 0.46831999493879, | |
18 | }; | |
19 | ||
20 | __PACKAGE__->register_color_space('luv'); | |
21 | ||
22 | sub new { | |
23 | my ($class, $l, $u, $v) = @_; | |
24 | ($l, $u, $v) = split /,/s, $l unless defined $u; | |
25 | bless [$l, $u, $v], $class | |
26 | } | |
27 | ||
28 | sub L { shift->[0] } | |
29 | sub u { shift->[1] } | |
30 | sub v { shift->[2] } | |
31 | ||
32 | sub luv { @{$_[0]} } | |
33 | ||
34 | sub _y_to_l { | |
35 | my ($y) = @_; | |
36 | $y <= EPS ? $y * KAPPA : 116 * ($y ** (1/3)) - 16 | |
37 | } | |
38 | ||
39 | sub _l_to_y { | |
40 | my ($l) = @_; | |
41 | $l <= 8 ? $l / KAPPA : (($l + 16) / 116) ** 3 | |
42 | } | |
43 | ||
44 | sub convert_to_xyz { | |
45 | my ($self) = @_; | |
46 | my ($l, $u, $v) = @$self; | |
47 | return Convert::Color::XYZ->new(0, 0, 0) unless $l; | |
48 | my $var_u = $u / (13 * $l) + REF_U; | |
49 | my $var_v = $v / (13 * $l) + REF_V; | |
50 | my $y = _l_to_y $l; | |
51 | my $x = 9 * $y * $var_u / (4 * $var_v); | |
52 | my $z = (9 * $y - (14 * $var_v * $y) - ($var_v * $x)) / (3 * $var_v); | |
53 | Convert::Color::XYZ->new($x, $y, $z) | |
54 | } | |
55 | ||
56 | sub new_from_xyz { | |
57 | my ($class, $xyz) = @_; | |
58 | my ($x, $y, $z) = @$xyz; | |
59 | my $l = _y_to_l $y; | |
60 | return $class->new(0, 0, 0) unless $l; | |
61 | my $var_u = (4 * $x) / ($x + 15 * $y + 3 * $z); | |
62 | my $var_v = (9 * $y) / ($x + 15 * $y + 3 * $z); | |
63 | my $u = 13 * $l * ($var_u - REF_U); | |
64 | my $v = 13 * $l * ($var_v - REF_V); | |
65 | $class->new($l, $u, $v) | |
66 | } | |
67 | ||
68 | sub rgb { shift->convert_to_xyz->rgb } | |
69 | sub new_rgb { shift->new_from_xyz(Convert::Color::XYZ->new_rgb(@_)) } | |
70 | ||
71 | 1; | |
72 | __END__ | |
73 | ||
74 | =encoding utf-8 | |
75 | ||
76 | =head1 NAME | |
77 | ||
78 | Convert::Color::LUV - a color value in the CIE 1976 (L*, u*, v*) color space | |
79 | ||
80 | =head1 SYNOPSIS | |
81 | ||
82 | use Convert::Color::LUV; | |
83 | my $red = Convert::Color::LUV->new(53.23711, 175.00982, 37.76509); | |
84 | my $green = Convert::Color::LUV->new('87.73552,-83.06712,107.41811'); | |
85 | ||
86 | use Convert::Color; | |
87 | my $blue = Convert::Color->new('luv:32.30087,-9.40241,-130.35109'); | |
88 | ||
89 | say $red->L; # 53.23711 | |
90 | say $red->u; # 175.00982 | |
91 | say $red->v; # 37.76509 | |
92 | say join ',', $blue->luv; # 32.30087,-9.40241,-130.35109 | |
93 | ||
94 | =head1 DESCRIPTION | |
95 | ||
96 | Objects of this class represent colors in the CIE 1976 (L*, u*, v*) color space. | |
97 | ||
98 | Methods: | |
99 | ||
100 | =over | |
101 | ||
102 | =item Convert::Color::LUV->B<new>(I<$l>, I<$u>, I<$v>) | |
103 | ||
104 | Construct a color from its components. | |
105 | ||
106 | =item Convert::Color::LUV->B<new>(I<"$l,$u,$v">) | |
107 | ||
108 | Construct a color from a string. The string should contain the three | |
109 | components, separated by commas. | |
110 | ||
111 | =item $luv->B<L> | |
112 | ||
113 | =item $luv->B<u> | |
114 | ||
115 | =item $luv->B<v> | |
116 | ||
117 | Accessors for the three components of the color. | |
118 | ||
119 | =item $luv->B<luv> | |
120 | ||
121 | Returns the three components as a list. | |
122 | ||
123 | =back | |
124 | ||
125 | =head1 SEE ALSO | |
126 | ||
127 | L<Convert::Color> | |
128 | ||
129 | =head1 AUTHOR | |
130 | ||
131 | Marius Gavrilescu, E<lt>marius@ieval.roE<gt> | |
132 | ||
133 | =head1 COPYRIGHT AND LICENSE | |
134 | ||
135 | Copyright (C) 2015 by Marius Gavrilescu | |
136 | ||
137 | This library is free software; you can redistribute it and/or modify | |
138 | it under the same terms as Perl itself, either Perl version 5.20.2 or, | |
139 | at your option, any later version of Perl 5 you may have available. | |
140 | ||
141 | ||
142 | =cut |