Moving UIView within UIImageView's UIImage in Swift - swift

Question

I am trying to move one image on base image.
If I am moving that UIView, it crosses UIImageView's image.
How to restrict UIView's move within UIImageView's image? It should supports for square and rectangle. Moving view should not cross its border.
Kindly guide me.
In the screen shots, UIImageView background color is black color.
Moving UIView is in white color. White color view is crossing its image [Screen Shot 2]. How to restrict within the image ?
Code:
#IBAction func panAcn(sender: UIPanGestureRecognizer) {
if sender.state == .Began || sender.state == .Changed {
let translation = sender.translationInView(self.myImgVw)
// note: 'view' is optional and need to be unwrapped
sender.view!.center = CGPointMake(sender.view!.center.x + translation.x, sender.view!.center.y + translation.y)
sender.setTranslation(CGPointMake(0,0), inView: self.myImgVw)
}
}
Need Output:
My Output

Answer 1

You may try this :
#IBAction func panAcn(sender: UIPanGestureRecognizer) {
if sender.state == .Began || sender.state == .Changed {
let translation = sender.translationInView(self.myImgVw)
// note: 'view' is optional and need to be unwrapped
guard let view = sender.view else { return }
var newFrame = view.frame
newFrame.origin.x = max(self.myImgVw.frame.origin.x, view.frame.origin.x + translation.y)
newFrame.origin.y = max(self.myImgVw.frame.origin.y, view.frame.origin.y + translation.y)
view.frame = newFrame
}
}