Form drawstring problem

Hi all

So I have a challenge to use a getpointsize method to find the biggest size font I can use to display a string in a form.

I'm guessing as all the other challenges has been to allow the form to change size by user and everything else resizes but I don't quite know how to look at the form size say 400x400 and how to go about looking to see what size will be the largest to fit.

Is there some kind of command to check if my string fits in the form?

Thanks