Android : Creating Dialog showing Zoomed Canvas Image

This is more an open question to point me in the right direction. I have a Framelayout with a Canvas on it. What I am looking to do is have the user touch on the Canvas and at that point a Dialog is shown showing a Zoomed in version of what is underneath touch. Like a magnifying glass

I have a custom Dialog already created so what am looking for is how to pass the canvas to the Dialog and then zoom it in.

Thanks for help