a.swift

private func cropImage(image: UIImage, normalisedRect: CGRect) -> UIImage? {
    let x = normalisedRect.origin.x * image.size.width
    let y = normalisedRect.origin.y * image.size.height
    let width = normalisedRect.width * image.size.width
    let height = normalisedRect.height * image.size.height

    let rect = CGRect(x: x, y: y, width: width, height: height).scaleUp(scaleUp: 0.1)

    guard let cropped = image.cgImage?.cropping(to: rect) else {
      return nil
    }

    let croppedImage = UIImage(cgImage: cropped, scale: image.scale, orientation: image.imageOrientation)
    return croppedImage
  }