drawboundingbox-vision-camera.swift

func drawBoundingBox(rect : VNRectangleObservation) {
    
    
let transform = CGAffineTransform(scaleX: 1, y: -1).translatedBy(x: 0, y: -self.previewLayer.frame.height)
    
let scale = CGAffineTransform.identity.scaledBy(x: self.previewLayer.frame.width, y: self.previewLayer.frame.height)
    
let bounds = rect.boundingBox.applying(scale).applying(transform)
createLayer(in: bounds)
}
private func createLayer(in rect: CGRect) {
        maskLayer = CAShapeLayer()
        maskLayer.frame = rect
        maskLayer.cornerRadius = 10
        maskLayer.opacity = 0.75
        maskLayer.borderColor = UIColor.red.cgColor
        maskLayer.borderWidth = 5.0
        
        previewLayer.insertSublayer(maskLayer, at: 1)
}