Different information values depending on how the metadata of the image is obtained (PHAsset vs PHPickerResult)

Question

mj.lee123 OP

Created 1w

Replies 0

Boosts 0

Participants 1

While customizing ImagePicker and using it, we find out that the metadata is not reflected normally and report it.

The situation is as follows.

The time or time zone of an image is changed in the Photos app. Changing the time zone of an image with an actual capture date of 2024:11:08 08:27:44 → 2024:11:07 17:27:44

width=324

Image data is extracted from a PHAsset using PHImageManager. The metadata is obtained from this image data. The time zone information exposed in the Exif tag information does not reflect the time or time zone changed in the Photos app.

let asset: PHAsset = ...

....

let options = PHImageRequestOptions()
options.isSynchronous = true
options.version = .current
options.deliveryMode = .highQualityFormat
options.resizeMode = .none
options.normalizedCropRect = .zero
options.isNetworkAccessAllowed = true
options.progressHandler = { progress, error, _, _ in }
PHImageManager.default().requestImageDataAndOrientation(for: asset, options: options) { imageData, uti, orientation, info in
    let cgImageSource = CGImageSourceCreateWithData(imageData! as CFData, nil)
    let properties = CGImageSourceCopyPropertiesAtIndex(cgImageSource!, 0, nil) as? Dictionary&lt;String, Any&gt;
    let exif = properties!["{Exif}"]
    let dictionary = exif as? Dictionary&lt;String, Any&gt;
}

Metadata Check

width=676;

In this case, it is reflected in the creationDate of PHAsset, so it can be somewhat compensated by forcibly replacing the metadata. However, because PHAsset does not include time zone information, when changing the time zone as well, it's impossible to calculate the correct time according to the time zone.

PHPicker

This issue is resolved when using the PHPickerResult provided by PHPicker.

extension PhotosPickerViewController: PHPickerViewControllerDelegate {
	  public func picker(_ picker: PHPickerViewController, 
										  didFinishPicking results: [PHPickerResult]) {
		  .....
	  
		  for result in results {
				  let identifier = UTType.image.identifier
          if result.itemProvider.hasItemConformingToTypeIdentifier(identifier) {
              result.itemProvider.loadDataRepresentation(forTypeIdentifier: identifier) { data, error in
                  guard let data = data,
                        let cgImageSource = CGImageSourceCreateWithData(data as CFData, nil),
                        let properties = CGImageSourceCopyPropertiesAtIndex(cgImageSource, 0, nil) as? Dictionary&lt;String, Any&gt;,
                        let exif = properties["{Exif}"],
                        let dictionary = exif as? Dictionary&lt;String, Any&gt;
                  else {
                      return
                  }
              }
          }
       }
	  }
}

Metadata Check

width=754

Question

I wonder why this happens, and if this is normal behavior. Instead of the System Picker that Apple provides as a base, I wonder if there is any way I can supplement it in that situation if I use a customizer.

Boost