override func touchesBegan(_ touches: Set<UITouch>,with event: 
UIEvent?) 
{
    let touch = event?.allTouches?.first
    let touchLocation: CGPoint? = touch?.location(in: self.view)
    //---Declare "from" globally  as CGPoint
    from = CGPoint(x: (touchLocation?.x)!,y: (touchLocation?.y)!)

}


override func touchesMoved(_ touches: Set<UITouch>,with event: UIEvent?) {

    let touch = event?.allTouches?.first
    let touchLocation: CGPoint? = touch?.location(in: self.view)

    //--Get New touch point
    let to = CGPoint(x: (touchLocation?.x)!,y: (touchLocation?.y)!)

    //--Draw line
    drawLineFromPoint(from: from,to: to,ofColor: UIColor.red,inView: self.view)

    //--Save as older point
    from = to

}


func drawLineFromPoint(from : CGPoint,to:CGPoint,ofColor lineColor: UIColor,inView view:UIView)
 {

    //design the path
    let path = UIBezierPath()
    path.move(to: from)
    path.addLine(to: to)

    //design path in layer
    let shapeLayer = CAShapeLayer()
    shapeLayer.path = path.cgPath
    shapeLayer.strokeColor = lineColor.cgColor
    shapeLayer.lineWidth = 1.0

    view.layer.addSublayer(shapeLayer)
}