This is a tough one.
complexity in order:
1, a simple contour, intersecting with the entity at two points. Solution seems to be simple, trim the inside portion or the the outside portions;
2, a simple contour, intersecting with the entity at more than two points, quite a few more cases to select the segment to keep;
3, not a contour, just collection of entities intersect the entity at N points, let's figure out an algorithm with good behavior first.
How to enable trimming of multiple/selected entities by a single entity? This seems to be easy to implement.
premper wrote
If you want to make an floor plan, you need to cut out a lot of windows and door openings. Librecad seems to have only a very limited trim function which allows only the selection of on line, but in the above described case I would rather select several lines as cutting limit and then cut all the pices I do not need at once.
Is there something I am missing ? If this funcionality does not exist I would pay a 50 USD bounty to whoever solves it.