ImageScanner+PostProcess.swift

extension ImageScanner {
    private func postProcessImage(_ image: UIImage) -> Result<UIImage, Error> {
        guard let ciImage = CIImage(image: image),
              let orientation = CGImagePropertyOrientation(rawValue: UInt32(image.imageOrientation.rawValue)) else {
            return .failure(ImageProviderError.internalError)
        }
        let inputImage = ciImage.oriented(forExifOrientation: Int32(orientation.rawValue))
        return detectRectangle(on: ciImage, orientation: orientation).flatMap {detectedRectangle in // ➊
            self.cropImage(inputImage, with: detectedRectangle) // ➋
        }
    }
}