How to create Trim with regions component by C#


I’m currently trying to create Trim with regions component as an exercise in C# coding, but there’s something I don’t understand.
I was able to split the curve, but I couldn’t figure out the process of determining the inside and outside of the split line.

Can anyone tell me which method in C# I should use and what approach I should use to achieve this?

First get the pieces (crv against a crvList):

Then … if you want inner/outer checks (nested or not) AND if there’s closed Curves in the cList … test each piece for containment (using a tmp trimmed [+tol/-tol] Curve derived from each piece … ot maybe better some point at the piece mid).

Try to do it and if things go the other way notify (never fear, Smith is here).