How to make UIImageView display properly? SWIFT

Question

I have a UIImageView in my app and I'm trying to make it display a wide, short picture. I'm trying to preserve the aspect ratio of the original image.

Here is my code. It currently does not work the way I want it to:

func scaleImage(oldImage: UIImage) -> UIImage {

  // 1. Use only y=273 to y=299

  let x = 0
  let y = Int(oldImage.size.height/2)
  let width = Int(oldImage.size.width)
  let height = 150
  let cropRect = CGRect(x: y, y: x, width: height, height: width)

  let cgImage = CGImageCreateWithImageInRect(oldImage.CGImage, cropRect)

  var image = UIImage(CGImage: cgImage!, scale:oldImage.scale, orientation: oldImage.imageOrientation)

  UIImageWriteToSavedPhotosAlbum(oldImage, nil, nil, nil)
  UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil)

  imageView.translatesAutoresizingMaskIntoConstraints = true

  imageView.image = image

  imageView.contentMode = UIViewContentMode.ScaleAspectFit

  imageView.frame.size.height = image.size.height
}

This is the edited image that was saved to the camera roll: https://i.stack.imgur.com/S3AwU.png

This is what was displayed on the UIImageView: https://i.stack.imgur.com/KX3OF.png

As you can see, the image is cut off on the sides. What am I missing here?