How to find out if a child control is actually visible to the user?

Question

WPF

I have a dynamic WrapPanel with a number of dynamically sized elements inside it. I need to increase the size of the parent panel until all child elements are visible. Is there any way to check if the element is actually visible? (And not hidden outside of the control). Or are there other ways to solve my problem?
The panel looks like this:
elements that I also need to display are highlighted in red. It is impossible to specify the dimensions of everything in advance, it is all drawn based on the received data.