How to change uiimageview content mode at runtime? - ios

Question

I have a UIViewController with an UIImageView, if I tap the screen, i want the UIImageView to change its contentMode. But I found out that this is not working with some images, mainly those from AVCaptureSession.
Screenshots:
Aspect fill
Aspect fit
I also found out that it's working fine when I change device orientation to landscape and back. But when I tap the screen is not working again.
Aspect fit after changed orientation to landscape and back (this is how I want it to look everytime in aspect fit)
My code:
CameraController:
class CameraController: UIViewController {
private var captureSession = AVCaptureSession()
private var captureDevice: AVCaptureDevice!
private var capturePhotoOutput = AVCapturePhotoOutput()
private var previewLayer: AVCaptureVideoPreviewLayer!
override func viewDidLoad() {
super.viewDidLoad()
setupCaptureSession()
setupCaptureDevice()
setupInputAndOutput()
setupPreviewLayer()
startCaptureSession()
setupLayout()
}
private func setupCaptureSession() {
captureSession.sessionPreset = .photo
}
private func setupCaptureDevice() {
guard let device = AVCaptureDevice.DiscoverySession(deviceTypes: [.builtInWideAngleCamera], mediaType: AVMediaType.video, position: .back).devices.first else { return }
captureDevice = device
}
private func setupInputAndOutput() {
do {
let captureDeviceInput = try AVCaptureDeviceInput(device: captureDevice)
captureSession.addInput(captureDeviceInput)
let captureSettings = AVCapturePhotoSettings(format: [AVVideoCodecKey: AVVideoCodecType.jpeg])
capturePhotoOutput.setPreparedPhotoSettingsArray([captureSettings], completionHandler: nil)
captureSession.addOutput(capturePhotoOutput)
} catch {
print(error.localizedDescription)
}
}
private func setupPreviewLayer() {
previewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
previewLayer.videoGravity = .resizeAspectFill
previewLayer.connection?.videoOrientation = .portrait
previewLayer.frame = view.frame
view.layer.insertSublayer(previewLayer, at: 0)
}
private func startCaptureSession() {
captureSession.startRunning()
}
private func setupLayout() {
let captureButton = UIButton(frame: CGRect(x: 0, y: 0, width: 44, height: 44))
captureButton.backgroundColor = .white
captureButton.layer.cornerRadius = 22
captureButton.addTarget(self, action: #selector(didPressCaptureButton), for: .touchUpInside)
captureButton.center.x = view.center.x
captureButton.center.y = view.frame.height - 50
view.addSubview(captureButton)
}
#objc private func didPressCaptureButton() {
let settings = AVCapturePhotoSettings()
capturePhotoOutput.capturePhoto(with: settings, delegate: self)
}
}
extension CameraController: AVCapturePhotoCaptureDelegate {
func photoOutput(_ output: AVCapturePhotoOutput, didFinishProcessingPhoto photo: AVCapturePhoto, error: Error?) {
guard let imageData = photo.fileDataRepresentation() else { return }
guard let image = UIImage(data: imageData) else { return }
print("Image size: ", image.size)
let previewController = PreviewController()
previewController.image = image
present(previewController, animated: true, completion: {
self.captureSession.stopRunning()
})
}
}
PreviewController:
class PreviewController: UIViewController {
var imageView: UIImageView!
var image: UIImage!
override func viewDidLoad() {
super.viewDidLoad()
setupImageView()
}
func setupImageView() {
imageView = UIImageView(image: image)
imageView.contentMode = .scaleAspectFill
view.addSubview(imageView)
imageView.addConstraintsToFillSuperview()
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
let contentMode: UIViewContentMode = imageView.contentMode == .scaleAspectFill ? .scaleAspectFit : .scaleAspectFill
imageView.contentMode = contentMode
}
}
What am I doing wrong here?
Thank You!

Answer 1

You can change ImageView contentMode on runtime with:
self.imageView.contentMode = newContentMode
self.imageView.setNeedsDisplay()