如何在Swift 4中将自定义值检索到图像元数据？

Question

Am creating an application for image share related things. Here my requirement is I have to store some custom information(Name, PhoneNumber, Price) into the Image Metadata and retrieve it back .

I use UIImagePickerController to capture the image and set my information into the image metadata in UIImagePickerControllerDelegate like below mentioned:

func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
    picker.dismiss(animated: true, completion: nil)
    let profileImage = info[UIImagePickerControllerOriginalImage] as? UIImage
    let imageData: Data = UIImageJPEGRepresentation(profileImage!, 1)!
    let cgImgSource: CGImageSource = CGImageSourceCreateWithData(imageData as CFData, nil)!
    let uti: CFString = CGImageSourceGetType(cgImgSource)!
    let dataWithExif: NSMutableData = NSMutableData(data: imageData)
    let destination: CGImageDestination = CGImageDestinationCreateWithData((dataWithExif as CFMutableData), uti, 1, nil)!
    let imageProoperties = CGImageSourceCopyPropertiesAtIndex(cgImgSource, 0, nil)! as NSDictionary
    let mutable: NSMutableDictionary = imageProoperties.mutableCopy() as! NSMutableDictionary

    let EXIFDictionary: NSMutableDictionary = (mutable[kCGImagePropertyExifDictionary as String] as? NSMutableDictionary)!
    print("Before Modification: \(EXIFDictionary)")
    EXIFDictionary[kCGImagePropertyExifUserComment as String] = "\(self.m_NameTxtFd.text!):\(self.m_PhoneNumberTxtFd.text!):\(self.m_PriceTxtFd.text!)"
    mutable[kCGImagePropertyExifDictionary as String] = EXIFDictionary

    CGImageDestinationAddImageFromSource(destination, cgImgSource, 0, (mutable as CFDictionary))
    CGImageDestinationFinalize(destination)

    let testImage: CIImage = CIImage(data: dataWithExif as Data, options: nil)!
    let newProperties: NSDictionary = testImage.properties as NSDictionary
    print("After Modification : \(newProperties)") //Here I Got My Information is Stored Successfully

    self.m_ImgView.image = self.convert(cmage: testImage)
    self.saveImageDocumentDirectory()
}

    func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
        picker.dismiss(animated: true, completion: nil)
    }

Now am going to save the image in NSDocumentDirectory like below mentioned:

func saveImageDocumentDirectory(){
        let fileManager = FileManager.default
        let paths = (NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0] as NSString).appendingPathComponent("apple.jpg")
        let image = self.m_ImgView.image
        print(paths)
        let imageData = UIImageJPEGRepresentation(image!, 0.5)
        fileManager.createFile(atPath: paths as String, contents: imageData, attributes: nil)
    }

Now am going to fetch the stored image in another view controller like below mentioned:

func getImage(){
        let fileManager = FileManager.default
        let imagePAth = (self.getDirectoryPath() as NSString).appendingPathComponent("apple.jpg")
        print(imagePAth)
        if fileManager.fileExists(atPath: imagePAth){
            self.m_ImgView.image = UIImage(contentsOfFile: imagePAth)
            self.fetchImageDetails()
        }else{
            print("No Image")
        }
    }

I successfully got the image and now I have to fetch the information from image metadata like below mentioned:

func fetchImageDetails() {
        let profileImage = self.m_ImgView.image!
        let ciImage: CIImage = CIImage(cgImage: profileImage.cgImage!)
        let newProperties: NSDictionary = ciImage.properties as NSDictionary
    }

But issue is the information is null in image property.

Please guide me to retrieve the custom information from stored Image.

Answer 1

First create NSMutableDictionary and set value to NSMutableDictionary when you set value to then you don't need to set again to metadata you directly assign to NSMutableDictionary to Metada.

    let metadata = info[UIImagePickerControllerMediaMetadata] as? NSMutableDictionary                
    let exifData = NSMutableDictionary()            
    let metaStr = "\(self.m_NameTxtFd.text!),\(self.m_PhoneNumberTxtFd.text!),\(self.m_PriceTxtFd.text!)"
    exifData.setValue(metaStr, forKey: kCGImagePropertyExifDictionary as String)                       
    metadata = exifData

Answer 2

fileManager.requestImageData(for: fetchResult.object(at: i) as PHAsset, options: requestOptions, resultHandler: { (imagedata, dataUTI, orientation, info ) in

 if let info = info {

if info.keys.contains(NSString(string: "PHImageFileURLKey")) {

 path = info[NSString(string: "PHImageFileURLKey")] as? NSURL

 size = (imagedata! as NSData).length

self.name = PHAssetResource.assetResources(for:fetchResult.object(at: i)).first?.originalFilename
 self.imageData = imagedata

           }
       }
   })