How do I use the metadataOutputRectOfInterestForRect method and rectOfInterest property to scan a specific area? (QR Code)

Question

I am building a QR code scanner with Swift and everything works in that regard. The issue I have is that I am trying to make only a small area of the entire visible A

Answer 1

I managed to create an effect of having a region of interest. I tried all the proposed solutions but the region was either a CGPoint.zero or had inappropriate size (after converting frames to a 0-1 coordinate). It's actually a hack for those who can't get the regionOfInterest to work and doesn't optimize the detection.

In:

func metadataOutput(_ output: AVCaptureMetadataOutput, didOutput metadataObjects: [AVMetadataObject], from connection: AVCaptureConnection) 

I have the following code:

let visualCodeObject = videoPreviewLayer?.transformedMetadataObject(for: metadataObj)
if self.viewfinderView.frame.contains(visualCodeObject.bounds) { 
    //visual code is inside the viewfinder, you can now handle detection
}