ViewController-Vision-ProcessPoints.swift

func processPoints(_ points: [CGPoint?]) {
        
        let previewLayer = cameraView.previewLayer
        var pointsConverted: [CGPoint] = []
        for point in points {
            pointsConverted.append(previewLayer.layerPointConverted(fromCaptureDevicePoint: point!))
        }

        let thumbTip = pointsConverted[0]
        let wrist = pointsConverted[pointsConverted.count - 1]
        
        let yDistance  = thumbTip.y - wrist.y

        if(yDistance > 50){

            if self.restingHand{
                self.restingHand = false
                self.handDelegate?.thumbsDown()
            }
            
        }else if(yDistance < -50){
            
            if self.restingHand{
                self.restingHand = false
                self.handDelegate?.thumbsUp()
            }
        }
        else{
            self.restingHand = true
        }

        cameraView.showPoints(pointsConverted)
    }