[cairo] How does one Normailze the Mouse Coordinates to the DrawingArea Box?

[Allen]

Hi all,

does anyone know how to normalize the mouse coordinates to be between 
0.0 ~ 1.0 within a particular DrawingArea?

I've just learned how to use the "scale" method for a cairo context but 
my mouse positions are coming in as Pixel positions and I've No idea how 
to tell if those positions are w/in the Drawing Area let alone how to 
normalize them to ONLY the drawing area.

Thank you for the help ahead of time!

--Allen