public static function contrast( $color, $dark = false, $light = false, $threshold = false) {
// filter: contrast(3.2);
// should be kept as is, so check for color
if( !property_exists($color,'rgb') ){
return null;
}
if( $light === false ){
$light = Less_Environment::rgba(255, 255, 255, 1.0);
}
if( $dark === false ){
$dark = Less_Environment::rgba(0, 0, 0, 1.0);
}
//Figure out which is actually light and dark!
if( $dark->luma() > $light->luma() ){
$t = $light;
$light = $dark;
$dark = $t;
}
if( $threshold === false ){
$threshold = 0.43;
} else {
$threshold = Less_Environment::number($threshold);
}
if( ($color->luma() * $color->alpha) < $threshold ){
return $light;
} else {
return $dark;
}
}
