using apple faceDetection sdk

Question

when i try to use apple faceDetection SDK it successfully detect the right eye position making bezier path over the two eyes.

i need Know to make image over the eye when it open and decrease the image width & height with the eye opening angle .

i use this function but not give me correct result

 func draw(points: [(x: CGFloat, y: CGFloat)]) {
        let newLayer = CAShapeLayer()
         newLayer.lineWidth = 2.0
         let path = UIBezierPath()

        path.move(to: CGPoint(x: points[0].x, y: points[0].y))
        for i in 0..<points.count - 1 {
            var point: CGPoint = .zero
            point = CGPoint(x: points[i].x, y: points[i].y)
            path.addLine(to: point)
            path.move(to: point)
            path.addLine(to: CGPoint(x: points[0].x, y: points[0].y))

        }

         newLayer.path = path.cgPath
         newLayer.contents = UIImage(named:"eye2.png")?.cgImage;
         newLayer.contentsGravity = kCAGravityResizeAspectFill
         newLayer.isGeometryFlipped = false

         print("Hello Swift",shapeLayer.bounds)

        shapeLayer.addSublayer(newLayer)

    }