###How to use

just copy this code

extension UIView{
func drawTest() -> () {
    
    
    let layer = CAShapeLayer()
    let bp = UIBezierPath()
    let kwidth = self.frame.size.width
    let kheight = self.frame.size.height
    
    bp.move(to: CGPoint.init(x: 0.01*kwidth, y: 0.5*kheight))
    bp.addLine(to: CGPoint.init(x: 0.3*kwidth, y: 0.5*kheight))
    bp.addLine(to: CGPoint.init(x: 0.33*kwidth, y: 0.47*kheight))
    bp.addLine(to: CGPoint.init(x: 0.38*kwidth, y: 0.54*kheight))
    bp.addLine(to: CGPoint.init(x: 0.44*kwidth, y: 0.5*kheight))
    bp.addLine(to: CGPoint.init(x: 0.50*kwidth, y: 0.30*kheight))
    bp.addLine(to: CGPoint.init(x: 0.56*kwidth, y: 0.57*kheight))
    bp.addLine(to: CGPoint.init(x: 0.61*kwidth, y: 0.5*kheight))
    bp.addLine(to: CGPoint.init(x: 0.7*kwidth, y: 0.5*kheight))
    bp.addLine(to: CGPoint.init(x: 0.75*kwidth, y: 0.48*kheight))
    bp.addLine(to: CGPoint.init(x: 0.80*kwidth, y: 0.5*kheight))
    bp.addLine(to: CGPoint.init(x: 0.99*kwidth, y: 0.5*kheight))
    
    layer.path = bp.cgPath
    layer.fillColor = UIColor.clear.cgColor
    layer.strokeColor = UIColor.red.cgColor
    layer.lineWidth = kwidth/360.0
    self.layer.addSublayer(layer)
    
    let an = CABasicAnimation.init(keyPath: "strokeEnd")
    an.duration = 1
    an.fromValue = 0
    an.toValue = 1
    an.timingFunction = CAMediaTimingFunction.init(name: kCAMediaTimingFunctionEaseInEaseOut)
    an.autoreverses = false
    an.repeatCount = MAXFLOAT
    layer .add(an, forKey: "heartbeat")
    print(layer.lineWidth)
}