/**
  * {@inheritdoc}
  */
 public function __construct(RGBColor $start = null, RGBColor $end = null, $step = 0)
 {
     parent::__construct($start, $end, $step);
     $this->setStep(6);
 }
 /**
  * construct new LinearGradient gradient
  *
  * @param string                 $type
  * @param \Jaguar\Color\RGBColor $start
  * @param \Jaguar\Color\RGBColor $end
  * @param integer                $step
  *
  * @throws \InvalidArgumentException
  */
 public function __construct($type = self::GRADIENT_VERTICAL, RGBColor $start = null, RGBColor $end = null, $step = 0)
 {
     parent::__construct($start, $end, $step);
     $this->setType($type);
 }