All you have to do is create a function and pass it the boundary of the rectangle that surrounds the text. Inside the function you check to see if the mouse is inside that boundary. If it is you return 1, if not return 0.

In the loop you check the boundaries of each menu item you want to highlite when the mouse is on it and if it returns 1 you highlite that rect boundary, if not do nothing. If you use -1 for the bg argument of your text output function to draw the text it should stay there when you highlite the rectangle around it. You may have to experiment with it a little to get it to work correctly.

Hope that helps.