Swift: Limiting Pinch to not go smaller then original and limit Zoom to no more then 3X

Question

I would like to place some limits on Pinching an image. The user should not be able to go smaller then the original image, and no more then 3X the original image. Tried a few things, but have not found a solution. Any help appreciated.

// Pinch gesture handler
func pinchHandler(recognizer:UIPinchGestureRecognizer) {
recognizer.view!.transform = CGAffineTransformScale(recognizer.view!.transform, recognizer.scale, recognizer.scale)
recognizer.scale = 1
}