public static function css2grayValue($css, $method = "rec601") { $rgb = Format::css2rgb($css); $rgb = Adjust::rgb2grayscale($rgb, $method); $gv = explode(",", $rgb); $gv = end($gv); $gv = intval($gv); $gv = $gv / 255; $gv = $gv * 100; return $gv; }