copy

Returns this object rebuilt around the replacement geometry line — the hook the shape-preserving operations return through.

Every operation that moves a line computes its result as a plain Line and returns it through this hook. This base implementation returns line itself; a subclass overrides it to rebuild an instance of its own class around line, and every such operation then comes back as that class. The result's runtime class must equal the receiver's — the operations check it and fail with a named error when a subclass misses the override.

Parameters