Can't use MediaPipeTasksVision with OpenCV on iOS.

[v-hogood]

Have I written custom code (as opposed to using a stock example script provided in MediaPipe)

No

OS Platform and Distribution

iOS 15.0

MediaPipe Tasks SDK version

0.10.14

Task name (e.g. Image classification, Gesture recognition etc.)

MediaPipeTasksVision

Programming Language and version (e.g. C++, Python, Java)

Swift

Describe the actual behavior

Build fails with 346 duplicate symbols.

Describe the expected behaviour

Build succeeds.

Standalone code/steps you may have used to try to get what you need

https://github.com/google-ai-edge/mediapipe-samples/tree/main/examples/image_classification/ios

Other info / Complete Logs

In the image_classification example add:
pod 'OpenCV-Dynamic-Framework'
to the Podfile.
Then try to build in Xcode and get:
duplicate symbol '_OBJC_CLASS_$_MatOfPoint3f' in:
    /Users/howardgood/Library/Developer/Xcode/DerivedData/ImageClassifier-dkioidhfgemwblbcqjglkdhicnlo/Build/Products/Debug-iphoneos/XCFrameworkIntermediates/MediaPipeTasksCommon/MediaPipeTasksCommon.framework/MediaPipeTasksCommon[1628](MatOfPoint3f.o)
    /Users/howardgood/Library/Developer/Xcode/DerivedData/ImageClassifier-dkioidhfgemwblbcqjglkdhicnlo/Build/Products/Debug-iphoneos/XCFrameworkIntermediates/OpenCV-Dynamic-Framework/opencv2.framework/opencv2[arm64][1006](MatOfPoint3f.o)
etc. etc.

[v-hogood]

MediaPipeTasksCommon xcframework should hide its public symbols like TensorFlowLite xcframework does:

https://github.com/tensorflow/tensorflow/blob/master/tensorflow/lite/ios/ios.bzl#L93

[schmidt-sebastian]

Hello - unfortunately, our setup makes hiding the symbols quite difficult since we need to reference the symbols from multiple Pods (MediaPipeTasksCommon and MediaPipeTasksVisions are the main ones). Are you able to build from source and create a single static library? Then symbol hiding becomes much more feasible.

[v-hogood]

I looked and all 346 OpenCV symbols are coming from MediaPipeTasksCommon, so I guess they need to be hidden there and whatever functionality MediaPipeTasksVision etc. uses needs to be wrapped with MediaPipe functions right?

I can try building from source but I'm sure I'm not the only one who's going to want MediaPipe with OpenCV. Can you point me at build instructions or even better build scripts for iOS and Android?