AVCaptureDevice builtInWideAngleCamera image does not match preview - swift

Question

I have a Swift project where I am using a UIImageView to show a live preview capture and 'freeze' this image whenever the uses clicks on a 'Take' photo button and have this shown in another UIImageView with identical dimensions and position.
This works great on devices that are able to use builtInDualCamera (such as a iPhone X) but on devices that rely on the fallback builtInWideAngleCamera (such as a 6th gen iPad Mini), the image appears cropped/zoomed in.
Can someone explain whether it is possible/how to get an image identical to the one shown in preview using the builtInDualCamera?
A minimal reproducible example can be found below (simply create a storyboard with 2 button and 2 UIImageViews and hook them up).
import UIKit
import AVFoundation
class ViewController: UIViewController, AVCaptureMetadataOutputObjectsDelegate, AVCapturePhotoCaptureDelegate {
#IBOutlet weak var cameraImageView: UIImageView!
#IBOutlet weak var userImageView: UIImageView!
var captureSession: AVCaptureSession? = AVCaptureSession()
var currentDevice: AVCaptureDevice?
var videoFileOutput: AVCaptureMovieFileOutput?
var cameraPreviewLayer: AVCaptureVideoPreviewLayer?
var cameraOutput : AVCapturePhotoOutput?
func setupCamSession(){
if #available(iOS 10.0, *) {
if let device = AVCaptureDevice.default(.builtInDualCamera, for: AVMediaType.video, position:.front) {
currentDevice = device
} else if let device = AVCaptureDevice.default(.builtInWideAngleCamera, for: AVMediaType.video, position: .front) {
currentDevice = device
}
} else {
// Fallback on earlier versions
let devices = AVCaptureDevice.devices().filter{ ($0 as AnyObject).hasMediaType(AVMediaType.video) && ($0 as AnyObject).position == AVCaptureDevice.Position.front }
if let captureDevice = devices.first {
currentDevice = captureDevice
}
}
if(currentDevice==nil)
{
print("failed")
return
}
else
{
captureSession?.sessionPreset = AVCaptureSession.Preset.medium
}
guard let captureDeviceInput = try? AVCaptureDeviceInput(device: currentDevice!) else {
return
}
if (captureSession?.canAddInput(captureDeviceInput))! {
captureSession?.addInput(captureDeviceInput)
cameraOutput = AVCapturePhotoOutput()
if (captureSession?.canAddOutput(cameraOutput!))! {
captureSession?.addOutput(cameraOutput!)
}
}
else
{
print("failed")
return
}
}
func startCamSession()
{
if (captureSession==nil)
{
print("Warning: no captureSession detected")
return
}
cameraPreviewLayer = AVCaptureVideoPreviewLayer(session: captureSession!)
cameraPreviewLayer?.videoGravity = AVLayerVideoGravity.resizeAspect
cameraPreviewLayer?.frame = cameraImageView.bounds
cameraImageView.layer.addSublayer(cameraPreviewLayer!)
if let connection = cameraPreviewLayer?.connection {
let previewLayerConnection : AVCaptureConnection = connection
if previewLayerConnection.isVideoOrientationSupported {
previewLayerConnection.videoOrientation = .portrait
cameraPreviewLayer?.frame = cameraImageView.bounds
}
captureSession?.startRunning()
}
}
func stopCamSession()
{
captureSession?.stopRunning()
}
func photoOutput(_ captureOutput: AVCapturePhotoOutput, didFinishProcessingPhoto photoSampleBuffer: CMSampleBuffer?, previewPhoto previewPhotoSampleBuffer: CMSampleBuffer?, resolvedSettings: AVCaptureResolvedPhotoSettings, bracketSettings: AVCaptureBracketedStillImageSettings?, error: Error?) {
if let error = error {
print(error.localizedDescription)
}
if let sampleBuffer = photoSampleBuffer, let previewBuffer = previewPhotoSampleBuffer {
let imageData = AVCapturePhotoOutput.jpegPhotoDataRepresentation(forJPEGSampleBuffer: sampleBuffer, previewPhotoSampleBuffer: previewBuffer)
let dataProvider = CGDataProvider(data: imageData! as CFData)
let cgImageRef = CGImage(jpegDataProviderSource: dataProvider!, decode: nil, shouldInterpolate: true, intent: CGColorRenderingIntent.absoluteColorimetric)
let image = UIImage(cgImage: cgImageRef!, scale: 1.0, orientation: UIImage.Orientation.leftMirrored)
self.userImageView.contentMode = .scaleAspectFit
self.userImageView.image = image
cameraPreviewLayer?.removeFromSuperlayer()
self.stopCamSession()
} else {
}
}
override func viewDidLoad() {
super.viewDidLoad()
setupCamSession()
}
#IBAction func startPressed(_ sender: Any) {
startCamSession()
}
#IBAction func takePhotoPressed(_ sender: Any) {
let settings = AVCapturePhotoSettings()
let previewPixelType = settings.availablePreviewPhotoPixelFormatTypes.first!
let previewFormat = [
kCVPixelBufferPixelFormatTypeKey as String : previewPixelType,
kCVPixelBufferWidthKey as String : 640,
kCVPixelBufferHeightKey as String : 480
]
settings.previewPhotoFormat = previewFormat
cameraOutput?.capturePhoto(with: settings, delegate: self)
}
}