Question

我使用以下代码制作图像形式QR Code：

  func createQRFromString(str: String) -> CIImage? {
        let stringData = str.dataUsingEncoding(NSUTF8StringEncoding)

        let filter = CIFilter(name: "CIQRCodeGenerator")

        filter?.setValue(stringData, forKey: "inputMessage")

        filter?.setValue("H", forKey: "inputCorrectionLevel")

        return filter?.outputImage
    }

然后我添加到UIImageView像这样：

    if let img = createQRFromString(strQRData) {
        let somImage = UIImage(CIImage: img, scale: 1.0, orientation: UIImageOrientation.Down)
        imgviewQRcode.image = somImage
    }

现在我需要将其保存到JPEG或PNG文件中。但是当我这样做时，我的应用程序崩溃了：

    @IBAction func btnSave(sender: AnyObject) {

    //        // Define the specific path, image name
    let documentsDirectoryURL = try! NSFileManager().URLForDirectory(.DocumentDirectory, inDomain: .UserDomainMask, appropriateForURL: nil, create: true)
    // create a name for your image
    let fileURL = documentsDirectoryURL.URLByAppendingPathComponent("image.jpg")

    if let image = imgviewQRcode.image // imgviewQRcode is UIImageView
    {

        if let path = fileURL?.path
        {
            if !NSFileManager.defaultManager().fileExistsAtPath(fileURL!.path!)
            {
                if UIImageJPEGRepresentation(image, 1.0)!.writeToFile(path, atomically: true)
                {
                    print("file saved")
                }

            }//Checking existing file

        }//Checking path

    }//CHecking image

}

崩溃点

  UIImageJPEGRepresentation(image, 1.0)!.writeToFile(path, atomically: true)

原因

fatal error: unexpectedly found nil while unwrapping an Optional value

调试测试：

Answer 1

func convert(cmage:CIImage) -> UIImage
{       
    let context:CIContext = CIContext.init(options: nil)
    let cgImage:CGImage = context.createCGImage(cmage, from: cmage.extent)!        
    let image:UIImage = UIImage.init(cgImage: cgImage)        
    return image
}

使用此功能将CIImage转换为UIImage。它有效。

Answer 2

我的最终代码

   func generateQRCode(from string: String) -> UIImage? {
        let data = string.data(using: String.Encoding.ascii)
        
        if let filter = CIFilter(name: "CIQRCodeGenerator") {
            filter.setValue(data, forKey: "inputMessage")
            let transform = CGAffineTransform(scaleX: 3, y: 3)
            
            if let output = filter.outputImage?.transformed(by: transform) {
                let context:CIContext = CIContext.init(options: nil)
                let cgImage:CGImage = context.createCGImage(output, from: output.extent)!
                let image:UIImage = UIImage.init(cgImage: cgImage)
                return image
            }
        }
        
        return nil
    }

Answer 3

 func convert(image:CIImage) -> UIImage
 {           
    let image:UIImage = UIImage.init(ciImage: image)        
    return image
 }

也许，之前没有这个，但现在可以直接从CIImage创建UIImages。

无法在Swift 3.0中将CIImage转换为UIImage

3 个答案: