How to read exif data from UIImage in swift 4?

Question

I have an image with a-lot of exif informations. But when trying to read the exif information with swift, it shows limited number of exif information.

I have tried following code:

let data = UIImageJPEGRepresentation(image, 1.0)
let source = CGImageSourceCreateWithData(data! as CFData, nil)
let metadata = (CGImageSourceCopyPropertiesAtIndex(source!, 0, nil))
debugPrint(metadata ?? "nil")

And it prints the following result:

    {
    ColorModel = RGB;
    Depth = 8;
    Orientation = 6;
    PixelHeight = 2448;
    PixelWidth = 3264;
    ProfileName = "sRGB IEC61966-2.1";
    "{Exif}" =     {
        ColorSpace = 1;
        PixelXDimension = 3264;
        PixelYDimension = 2448;
    };
    "{JFIF}" =     {
        DensityUnit = 0;
        JFIFVersion =         (
            1,
            0,
            1
        );
        XDensity = 72;
        YDensity = 72;
    };
    "{TIFF}" =     {
        Orientation = 6;
    };
}

How can I read all the exif information from UIImage?

Answer 1

if your image is captured using avcapturesession.than following is code for extract exif Data.

photoFileOutput?.captureStillImageAsynchronously(from: videoConnection, completionHandler: {(sampleBuffer, error) in
                if (sampleBuffer != nil) {
                        let imageData = AVCaptureStillImageOutput.jpegStillImageNSDataRepresentation(sampleBuffer!)
                        let image = self.processPhoto(imageData!)
                        let source: CGImageSource = CGImageSourceCreateWithData((imageData as! CFMutableData), nil)!

                        let metadata = CGImageSourceCopyPropertiesAtIndex(source, 0,nil) as! [String:Any]

                        print("exif data = \(metadata![kCGImagePropertyExifDictionary as String] as? [String : AnyObject]) ")

                        completionHandler(true)
                    } else {
                        completionHandler(false)
                    }
                }

Answer 2

My suspicion is UIImageJPEGRepresentation function is the culprit as it does the conversion from HEIC to JPEG (assuming you're pulling images from the Photos app). A lot of valuable Exif tags, including things like geo-location seem to get lost during this conversion.