How do I add a UIview to an imageView while ensuring that the contents of the UIView are inside the it's frame? - ios

Question

I have a superview which contains a ImageView, a testView, and some buttons. I created a UIView which contains ImageView2 and a removebutton.
When I add UIView to UIImageView, the contents of UIView are not in the frame of UIView. Because of that, I cannot apply pan gesture recognizer.
I have tried to apply constraints and to change the frame and centre of ImageView2.
Below is the code I am using to create the above mentioned UIView. How do I ensure that the contents of the UIView are visible in the frame of the UIView?
let rect = CGRect(x: self.imageView.center.x-30, y: self.imageView.center.y-30, width: 80, height: 80)
testview = UIView(frame: rect)
testview.layer.cornerRadius = testview.frame.width/2
testview.backgroundColor = UIColor.blackColor()
testview.clipsToBounds = true
imageView2 = UIImageView(frame: CGRect(x: testview.frame.minX+10, y: testview.frame.minY+10, width: 60, height: 60))
let rect2 = CGRect(x: self.testview.frame.maxX-17, y: self.testview.frame.minY, width: 20, height: 20)
removeButton = UIButton(frame: rect2)
removeButton.layer.cornerRadius = removeButton.frame.width/2
removeButton.backgroundColor = UIColor.blackColor()
removeButton.clipsToBounds = true
imageView2.layer.cornerRadius = imageView2.frame.width/2
imageView2.userInteractionEnabled = true
imageView2.clipsToBounds = true
testview.alpha = 0.3
imageView2.center = testview.center
imageView2.center = testview.center
testview.addSubview(imageView2)
testview.addSubview(removeButton)
testview.bringSubviewToFront(imageView2)
imageView.addSubview(testview)

Answer 1

The problem is that lines like this do not do what you think:
let rect = CGRect(x: self.imageView.center.x-30, y: self.imageView.center.y-30, width: 80, height: 80)
// ... and ...
imageView2.center = testview.center
The center of a view is in its frame coordinates - it has to do with how the view is placed in its superview. But the position of a subview must be described in terms of its superviews bounds, not its frame. Its bounds are its internal coordinates, which is what you want.
Let's take the simplest case: how to center a subview in a superview. This is not the way:
imageView2.center = testview.center
You see the problem? testview.center is where testview is located in its superview; it is not the internal center of testview, which is what you want. The internal center of testview comes from its bounds. This is the way:
let c = CGPointMake(testview.bounds.midX, testview.bounds.midY)
imageView2.center = c