//创建二维码图片
    func createQRForString(qrString: String?, qrImage: UIImage?) -> UIImage?{
        if let sureQRString = qrString {
            let stringData = sureQRString.data(using: .utf8, allowLossyConversion: false)
            // 创建一个二维码的滤镜
            let qrFilter = CIFilter(name: "CIQRCodeGenerator")!
            qrFilter.setValue(stringData, forKey: "inputMessage")
            qrFilter.setValue("H", forKey: "inputCorrectionLevel")
            let qrCIImage = qrFilter.outputImage
            
            // 创建一个颜色滤镜,黑白色
            let colorFilter = CIFilter(name: "CIFalseColor")!
            colorFilter.setDefaults()
            colorFilter.setValue(qrCIImage, forKey: "inputImage")
            colorFilter.setValue(CIColor(red: 0, green: 0, blue: 0), forKey: "inputColor0")
            colorFilter.setValue(CIColor(red: 1, green: 1, blue: 1), forKey: "inputColor1")
            
            // 返回二维码image
            //let codeImage = UIImage(ciImage: colorFilter.outputImage!.applying(CGAffineTransform(scaleX: 5, y: 5)))
            let codeImage = UIImage(ciImage: colorFilter.outputImage!.transformed(by: CGAffineTransform(scaleX: 5, y: 5)))
            
            // 通常,二维码都是定制的,中间都会放想要表达意思的图片
            if let iconImage = qrImage {
                let rect = CGRect(x:0, y:0, width:codeImage.size.width,
                                  height:codeImage.size.height)
                UIGraphicsBeginImageContext(rect.size)
                
                codeImage.draw(in: rect)
                let avatarSize = CGSize(width:rect.size.width * 0.25, height:rect.size.height * 0.25)
                let x = (rect.width - avatarSize.width) * 0.5
                let y = (rect.height - avatarSize.height) * 0.5
                iconImage.draw(in: CGRect(x:x, y:y, width:avatarSize.width, height:avatarSize.height))
                let resultImage = UIGraphicsGetImageFromCurrentImageContext()
                
                UIGraphicsEndImageContext()
                return resultImage
            }
            return codeImage
        }
        return nil
    }

• https://www.hangge.com/blog/cache/detail_909.html