EXIF value types are not considered properly.

[ER-lee-byeoksan]

I'm trying to work around orientation issue from react-native-vision-camera with the following code snippet and I found that EXIF tag Orientation is not updated properly.

async function fixRotation(file: PhotoFile) {
  const uri = `file://${file.path}`;
  const tags = await Exify.readAsync(uri);

  if (tags?.Orientation != null && tags.Orientation !== 0) {
    return;
  }

  // See https://exiftool.org/TagNames/EXIF.html
  const Orientation = {
    portrait: 1,
    'portrait-upside-down': 3,
    'landscape-left': 8, // sensor orientation is 90
    'landscape-right': 6, // sensor orientation is 270
  }[file.orientation];

  await Exify.writeAsync(`file://${file.path}`, {
    Orientation,
  });
}

I think the reason is that Orientation tag accepts integer but the native module updates as floating point value.

react-native-exify/android/src/main/java/com/lodev09/exify/ExifyModule.kt

Lines 54 to 66 in cb3c315

	for ((_, tag) in EXIFY_TAGS) {
	if (!tags.hasKey(tag)) continue
	val type = tags.getType(tag)
	when (type) {
	ReadableType.Boolean -> exif.setAttribute(tag, tags.getBoolean(tag).toString())
	ReadableType.Number -> exif.setAttribute(tag, tags.getDouble(tag).toBigDecimal().toPlainString())
	ReadableType.String -> exif.setAttribute(tag, tags.getString(tag))
	ReadableType.Array -> exif.setAttribute(tag, tags.getArray(tag).toString())
	else -> exif.setAttribute(tag, tags.getString(tag))
	}
	}

I checked that the following code snippet updates Orientation tag well but I didn't test with iOS because I have no background with iOS dev.

        for ((valType, tag) in EXIFY_TAGS) {
          if (!tags.hasKey(tag)) continue

          val type = tags.getType(tag)

          when (type) {
            ReadableType.Boolean -> exif.setAttribute(tag, tags.getBoolean(tag).toString())
            ReadableType.Number ->
            when (valType) {
              "double" -> exif.setAttribute(tag, tags.getDouble(tag).toBigDecimal().toPlainString())
              else -> exif.setAttribute(tag, tags.getDouble(tag).toInt().toString())
            }
            ReadableType.String -> exif.setAttribute(tag, tags.getString(tag))
            ReadableType.Array -> exif.setAttribute(tag, tags.getArray(tag).toString())
            else -> exif.setAttribute(tag, tags.getString(tag))
          }
        }

[lodev09]

I just tested it and it does update the orientation correctly on Android. Checking valType there doesn't really help much since the value is converted into string anyways.

Anyways, about your use-case, I would recommend providing the orientation prop of the Camera instead, before taking photo. You'll have to detect this while the user rotates their phone. You can use something like expo-orientation or expo-sensor.

<Camera
  orientation={deviceOrientation}
  // ...
/>

I do this on the App I'm working on and it's working great. There's a "little" delay when the camera view orientation changes which is acceptable and not very noticeable.

Modifying the Orientation works only for photo viewers that respects it -- photo editors and such will not. If I remember correctly, VisionCamera always resolves to orientation 6.

Hope that helps.

[ER-lee-byeoksan]

Converting the value into string makes different target value (Orientation 6 vs Orientation 6.0) and the result may depend on the devices (I cannot test all physical devices, you know). I tested it with Pixel_3a emulator and it didn't work. At least, I found a case where it does not update EXIF properly. So I suggested to make it more robust.

I would recommend providing the orientation prop of the Camera instead

I'm not sure this is working as the issue is to make orientation prop works. Anyway, thanks for the suggestion. Forget about it because this is not the actual issue for this package.

Modifying the Orientation works only for photo viewers that respects it

This is my exact use case so I needed to write EXIF Orientation tag.

If you didn't, could you test it with some emulators?

[lodev09]

Hmmm, okay that might make sense.. can you open up a PR plesae?

[devhubmarius]

I still facing the issue that the Orientation and some other tags e.g. InterlaceType cannot be updated on iOS.

Are there any updates?