Instagram like Pinch to Zoom + Translation

Trying to use a pinch gesture to move an image much like Instagram. Normal if this was a pan, I'd use translation using CGPoints and center it to a view.

I've currently been able to zoom like so:

@IBAction func handleShirtsZoom(_ sender: UIPinchGestureRecognizer) {
    self.view.bringSubview(toFront: shirts)
    sender.view?.transform = (sender.view?.transform)!.scaledBy(x: sender.scale, y: sender.scale)
    sender.scale = 1.0
}

How can I do both a zoom and a pan?