ios - Swift 如何修改从手机相机拍摄的图像中的 exif 信息

Question

我使用 UIImagePickerController 在我的 iOS 应用程序中选择图像，我知道可以通过 info[UIImagePickerControllerMediaMetadata] 获取 exif 信息。但是当我通过 UIImage 将我的图像上传到我的服务器时，大部分 exif 信息都被 strip 化了。我想知道我是否可以在 Http 请求中将 exif 信息添加到我的图像中(之后图像以 jpg 格式上传)。如果没有，我应该如何解决这个问题？我想更改 Make、Model 属性(换句话说，就是用什么设备拍摄这张照片)

下面是我的代码片段:

func Tapped() {
    let myPickerController = UIImagePickerController()

    myPickerController.delegate = self
    myPickerController.sourceType = UIImagePickerControllerSourceType.Camera
    myPickerController.allowsEditing = false
    self.presentViewController(myPickerController, animated: true, completion: nil)
}
func imagePickerController(picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : AnyObject]) {
    let image = info[UIImagePickerControllerOriginalImage] as? UIImage
    myImageView.image = image
    UIImageWriteToSavedPhotosAlbum(image!, self, #selector(ViewController.image(_:didFinishSavingWithError:contextInfo:)), nil)
    self.dismissViewControllerAnimated(true, completion: nil)
}

func myImageUploadRequest()
{

    let myUrl = NSURL(string: "http://XXXXXX/Uploadfile")

    let request = NSMutableURLRequest(URL:myUrl!)
    request.HTTPMethod = "POST"

    let param = [
        "userId"    : "7"
    ]

    let boundary = generateBoundaryString()

    request.setValue("multipart/form-data; boundary=\(boundary)", forHTTPHeaderField: "Content-Type")


    let imageData = UIImageJPEGRepresentation(myImageView.image!, 1)

    if(imageData == nil)  { return; }

    request.HTTPBody = createBodyWithParameters(param, filePathKey: "file", imageDataKey: imageData!, boundary: boundary)



    myActivityIndicator.startAnimating()

    let task = NSURLSession.sharedSession().dataTaskWithRequest(request) {
        data, response, error in

        if error != nil {
            print("error=\(error)")
            return
        }

        // You can print out response object
        print("******* response = \(response)")

        // Print out response body
        let responseString = NSString(data: data!, encoding: NSUTF8StringEncoding)
        print("****** response data = \(responseString!)")

        do{
            let json = try NSJSONSerialization.JSONObjectWithData(data!, options: .MutableContainers) as? NSDictionary

        }catch{
            print(error)
        }


        dispatch_async(dispatch_get_main_queue(),{
            self.myActivityIndicator.stopAnimating()
            self.myImageView.image = nil
        })

    }

    task.resume()
}

func createBodyWithParameters(parameters: [String: String]?, filePathKey: String?, imageDataKey: NSData, boundary: String) -> NSData {
    let body = NSMutableData();

    if parameters != nil {
        for (key, value) in parameters! {
            body.appendString("--\(boundary)\r\n")
            body.appendString("Content-Disposition: form-data; name=\"\(key)\"\r\n\r\n")
            body.appendString("\(value)\r\n")
        }
    }

    let filename = "test.jpg"

    let mimetype = "image/jpg"

    body.appendString("--\(boundary)\r\n")
    body.appendString("Content-Disposition: form-data; name=\"\(filePathKey!)\"; filename=\"\(filename)\"\r\n")
    body.appendString("Content-Type: \(mimetype)\r\n\r\n")
    body.appendData(imageDataKey)
    body.appendString("\r\n")



    body.appendString("--\(boundary)--\r\n")

    return body
}

func generateBoundaryString() -> String {
    return "Boundary-\(NSUUID().UUIDString)"
}

extension NSMutableData {
    func appendString(string: String) {
        let data = string.dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: true)
        appendData(data!)
    }
}

Answer 1

是的!最后我做了一个修改 EXIF 信息的技巧。首先，您可以从 info[UIImagePickerControllerMediaMetadata] 和 NSData 获取 EXIF 信息，而无需从 UIImageJPEGRepresentation 选取的 UIImage 获取 EXIF。然后，您可以使用修改后的 EXIF 信息创建一个新的 NSDictionary。之后在下面调用我的函数，就可以得到修改后的EXIF的图片NSData!

func saveImageWithImageData(data: NSData, properties: NSDictionary, completion: (data: NSData, path: NSURL) -> Void) {

    let imageRef: CGImageSourceRef = CGImageSourceCreateWithData((data as CFDataRef), nil)!
    let uti: CFString = CGImageSourceGetType(imageRef)!
    let dataWithEXIF: NSMutableData = NSMutableData(data: data)
    let destination: CGImageDestinationRef = CGImageDestinationCreateWithData((dataWithEXIF as CFMutableDataRef), uti, 1, nil)!

    CGImageDestinationAddImageFromSource(destination, imageRef, 0, (properties as CFDictionaryRef))
    CGImageDestinationFinalize(destination)

    var paths: [AnyObject] = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)
    let savePath: String = paths[0].stringByAppendingPathComponent("exif.jpg")

    let manager: NSFileManager = NSFileManager.defaultManager()
    manager.createFileAtPath(savePath, contents: dataWithEXIF, attributes: nil)

    completion(data: dataWithEXIF,path: NSURL(string: savePath)!)

    print("image with EXIF info converting to NSData: Done! Ready to upload! ")

}