Cropping a captured image exactly to how it looks in AVCaptureVideoPreviewLayer

Question

I have a photo app that is using AV Foundation. I have setup a preview layer using AVCaptureVideoPreviewLayer that takes up the top half of the screen. So when the user is tryin

Answer 1

Here's @Erik Allen's answer in Swift 3:

let originalSize: CGSize
let visibleLayerFrame = self?.photoView.bounds

// Calculate the fractional size that is shown in the preview
let metaRect = (self?.videoPreviewLayer?.metadataOutputRectOfInterest(for: visibleLayerFrame ?? CGRect.zero)) ?? CGRect.zero

if (image.imageOrientation == UIImageOrientation.left || image.imageOrientation == UIImageOrientation.right) {
    // For these images (which are portrait), swap the size of the
    // image, because here the output image is actually rotated
    // relative to what you see on screen.
    originalSize = CGSize(width: image.size.height, height: image.size.width)
} else {
    originalSize = image.size
}

let cropRect: CGRect = CGRect(x: metaRect.origin.x * originalSize.width, y: metaRect.origin.y * originalSize.height, width: metaRect.size.width * originalSize.width, height: metaRect.size.height * originalSize.height).integral

if let finalCgImage = image.cgImage?.cropping(to: cropRect) {
    let finalImage = UIImage(cgImage: finalCgImage, scale: 1.0, orientation: image.imageOrientation)

    // User your image...
}