Determining location of the staff lines

[Eric Knapp]

Hi, everyone.

I'm working on developing StaffTab notation for the Chapman Stick. I
have attached an image that shows something I need to do. In a Scheme
engraver, I can get the string number that was notated. Then I need to
be able to draw the little rectangle on the staff to indicate which
string the composer suggests for this note. How do I know where the
location of the staff lines are so I can draw that rectangle?

Thanks,

-Eric

stringIndicator25.jpg
Description: JPEG image