add_center_image_ciImage.swift

private func addLogo(image: CIImage, logo: UIImage) -> CIImage? {
        
        guard let combinedFilter = CIFilter(name: "CISourceOverCompositing") else { return nil }
        guard let logo = logo.cgImage else {
            return image
        }
        
        let ciLogo = CIImage(cgImage: logo)

        
        let centerTransform = CGAffineTransform(translationX: image.extent.midX - (ciLogo.extent.size.width / 2), y: image.extent.midY - (ciLogo.extent.size.height / 2))
        
        combinedFilter.setValue(ciLogo.transformed(by: centerTransform), forKey: "inputImage")
        combinedFilter.setValue(image, forKey: "inputBackgroundImage")
        return combinedFilter.outputImage
    }