start implement lab

Author: lichtkind

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

@@ -5,27 +5,36 @@ use warnings;
 
 package Graphics::Toolkit::Color::Space::Instance::LAB;
 use Graphics::Toolkit::Color::Space;
+ se Graphics::Toolkit::Color::Space::Util qw/mult_matrix apply_d65 remove_d65/;
 
-my ($i_max, $q_max)   = (0.5959, 0.5227);
-my ($i_size, $q_size) = (2 * $i_max, 2 * $q_max);
-                                                                    # cyan-orange balance, magenta-green balance
-my  $lab_def = Graphics::Toolkit::Color::Space->new( axis => [qw/L* a* b*/],
+my  $lab_def = Graphics::Toolkit::Color::Space->new( axis => [qw/L* a* b*/], # 
                                                    prefix => 'CIE',
-                                                    range => [1, [-$i_max, $i_max], [-$q_max, $q_max]] );
+                                                    range => [100, 500, 200] );
 
     $lab_def->add_converter('RGB', \&to_rgb, \&from_rgb );
 
 sub from_rgb {
     my ($r, $g, $b) = @_;
-    my $y =           (0.299  * $r) + ( 0.587  * $g) + ( 0.114  * $b);
-    my $i = ($i_max + (0.5959 * $r) + (-0.2746 * $g) + (-0.3213 * $b)) / $i_size;
-    my $q = ($q_max + (0.2115 * $r) + (-0.5227 * $g) + ( 0.3112 * $b)) / $q_size;
-    return ($y, $i, $q);
+    my ($x, $y, $z) = mult_matrix([[0.4124564, 0.2126729, 0.0193339],
+                                   [0.3575761, 0.7151522, 0.1191920],
+                                   [0.1804375, 0.0721750, 0.9503041]], 
+                                   apply_d65( $r ), apply_d65( $g ), apply_d65( $b ));
+    $x /= 0.95047;
+    $z /= 0.108883;
+    
+    $x = ($x > 0.008856) ? ($x ** (1/3)) : (7.7870689 * $x + 0.137931034);
+    $y = ($y > 0.008856) ? ($y ** (1/3)) : (7.7870689 * $y + 0.137931034);
+    $z = ($z > 0.008856) ? ($z ** (1/3)) : (7.7870689 * $z + 0.137931034);
+
+    my $l = (116 * $y) - 16;
+    my $a = 500 * ($x - $y);
+    my $b = 200 * ($y - $z);
+    return ($l, $a, $b);
 }
 
 
 sub to_rgb {
-    my ($y, $i, $q) = @_;
+    my ($l, $a, $b) = @_;
     $i = ($i * $i_size) - $i_max;
     $q = ($q * $q_size) - $q_max;
     my $r = $y + ( 0.956 * $i) + ( 0.619 * $q);
@@ -38,27 +47,3 @@ $lab_def;
 
 __END__
 
-sub from_rgb {
-    my ($r, $g, $b) = @_;
-    $r = ( $r > 0.04045 ) ? ((($r + 0.055) / 1.055 ) ** 2.4) : ($r / 12.92);
-    $g = ( $g > 0.04045 ) ? ((($g + 0.055) / 1.055 ) ** 2.4) : ($g / 12.92);
-    $b = ( $b > 0.04045 ) ? ((($b + 0.055) / 1.055 ) ** 2.4) : ($b / 12.92);
-
-    my $x =  (0.4124564 * $r) + ( 0.3575761 * $g) + ( 0.1804375 * $b);
-    my $y =  (0.2126729 * $r) + ( 0.7151522 * $g) + ( 0.0721750 * $b);
-    my $z =  (0.0193339 * $r) + ( 0.1191920 * $g) + ( 0.9503041 * $b);
-    return ($x, $y, $z);
-}
-
-
-sub to_rgb {
-    my ($x, $y, $z) = @_;
-    my $r =  ( 3.2404542 * $x) + (-1.5371385 * $y) + (-0.4985314 * $z);
-    my $g =  (-0.9692660 * $x) + ( 1.8760108 * $y) + ( 0.0415560 * $z);
-    my $b =  ( 0.0556434 * $x) + (-0.2040259 * $y) + ( 1.0572252 * $z);
-
-    $r = ($r > 0.003131) ? ((($r**0.416666) * 1.055) - 0.055) : $r * 12.92;
-    $g = ($g > 0.003131) ? ((($g**0.416666) * 1.055) - 0.055) : $g * 12.92;
-    $b = ($b > 0.003131) ? ((($b**0.416666) * 1.055) - 0.055) : $b * 12.92;
-    return ($r, $g, $b);
-}