Swift Vision Framework - VNRecognizeTextRequest：传递给不带参数的调用的参数

Posted 2023-03-27

【中文标题】Swift Vision Framework - VNRecognizeTextRequest：传递给不带参数的调用的参数

【英文标题】：Swift Vision Framework - VNRecognizeTextRequest: argument passed to call that takes no arguments

【发布时间】：2021-09-04 12:38:21

【问题描述】：

我目前正在 Swift 5.4 中构建一个小型 CLI 工具，并希望使用 Vision Framework 来提取图像中的所有文本。我为完成此任务而关注的文章由 Apple 提供，可以在 here 找到。如您所见，我的代码与 Apple 提供的示例相同，目前无法正常工作。

这是编译错误：

error: argument passed to call that takes no arguments
        let request = VNRecognizeTextRequest(completion: recognizeTextRequestHandler)

这是带有VNRecognizeTextRequest 类的代码，其中recognizeTextRequestHandler 函数被传递给构造函数以处理结果。

@available(macOS 10.13, *)
    public func run() throws 
        // Get the image from argument and create a UIImage
        let file = try Files.File.init(path: arguments[1]).read()
        guard let image = UIImage(data: file)?.cgImage else  return 
        
        
        // request
        let imageRequestHandler = VNImageRequestHandler(cgImage: image)
        // pass handler to process the result
        let request = VNRecognizeTextRequest(completion: recognizeTextRequestHandler)
        
        do 
            // Perform the text-recognition request.
            try imageRequestHandler.perform([request])
         catch 
            print("Unable to perform the requests: \(error).")
        
    

传入VNRecognizeTextRequest的函数

@available(macOS 10.13, *)
func recognizeTextRequestHandler(request: VNRequest, error: Error?)
    if #available(macOS 10.15, *) 
        guard let observations =
                request.results as? [VNRecognizedTextObservation] else 
            return
        
        let recognizedStrings = observations.compactMap  observation in
                // Return the string of the top VNRecognizedText instance.
                return observation.topCandidates(1).first?.string
            
            
            // Process the recognized strings.
            print(recognizedStrings)
     else 
        exit(EXIT_FAILURE)
    

感谢您的宝贵时间！如果有不清楚的地方请评论。

【参考方案1】：

文章已过时 - 应该是 completionHandler，而不是 completion。替换：

let request = VNRecognizeTextRequest(completion: recognizeTextRequestHandler)

...与：

let request = VNRecognizeTextRequest(completionHandler: recognizeTextRequestHandler)

【参考方案2】：

使用这个构造函数

let request = VNRecognizeTextRequest(completionHandler: recognizeTextRequestHandler)