     private var tempShadowRadius: CGFloat = 0
     private var tempShadowOpacity: Float = 0
     private var touchCenterLocation: CGPoint?
+    private var touchUpAnimationTime: NSTimeInterval = 0.1
     
     private var rippleMask: CAShapeLayer? {
         get {

                self.rippleBackgroundView.alpha = 1
            },
            completion: {(success: Bool) -> () in
                UIView.animateWithDuration(0.6 ,
                    animations: {
                        self.rippleBackgroundView.alpha = 0
                    }, completion: nil)

    @IBInspectable var shadowRippleRadius: Float = 1
    @IBInspectable var shadowRippleEnable: Bool = true
    @IBInspectable var trackTouchLocation: Bool = false
    @IBInspectable var fastTouchUpResponse: Bool = true {
        didSet {
            if fastTouchUpResponse {
                touchUpAnimationTime = 0.1
            } else {
                touchUpAnimationTime = 0.6
            }
        }
    }
    
    let rippleView = UIView()
    let rippleBackgroundView = UIView()
