How to crop an image from AVCapture to a rect seen on the display

Question

This is driving me crazy because I can\'t get it to work. I have the following scenario:

I\'m using an AVCaptureSession and an AVCaptureVideoPreviewLa

Answer 1

In Swift 4:

I prefer to never force-unwrap to avoid crashes, so I use optionals and guards in mine.

private func cropToPreviewLayer(originalImage: UIImage) -> UIImage? {
    guard let cgImage = originalImage.cgImage else { return nil }

    let outputRect = previewLayer.metadataOutputRectConverted(fromLayerRect: previewLayer.bounds)

    let width = CGFloat(cgImage.width)
    let height = CGFloat(cgImage.height)
    let cropRect = CGRect(x: outputRect.origin.x * width, y: outputRect.origin.y * height, width: outputRect.size.width * width, height: outputRect.size.height * height)

    if let croppedCGImage = cgImage.cropping(to: cropRect) {
        return UIImage(cgImage: croppedCGImage, scale: 1.0, orientation: originalImage.imageOrientation)
    }

    return nil
}