Silver Challenge: Pinch to Zoom Question


I have a question about the challenge. What is the correct way to go about drawing the concentric circles to fit the scaled view? It seems as though the hypnosisView is unaware of the transformation applied to it ( makes sense since it is using its own bounds to calculate center, extent, etc ). How does one go about drawing the rings all the way out in the case where the minimum zoom is less than 1?