Vista - Sizing Text in Custom Control?

All:

I am developing a WPF custom control. When displayed at run-time, the
control displays text. Is it possible to tell the control to scale it's
text (automatically) as the control grows and shrinks (the control
itself stretches in response to its container being resized)?

Thanks,
jpuopolo

PS. If not, I can always calculate the size of the text as some
percentage of the size of the control, but I figured it was best to ask
the question.