Hmm, in my reply, I was only thinking in terms of having the airfoil section on paper and determining where on the airfoil the chord line runs. This has no relation at all to sweep or taper. I may have missed the intention of the original question

Normally, the wing is designed with the airfoil section (and thus the chord line) parallel to the centerline, regardless of wing planform. Sorry for any (my) confusion.