copy

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

Every operation that moves or reshapes a polygon computes its result as a plain Polygon and returns it through this hook. This base implementation returns polygon itself; a subclass overrides it to rebuild an instance of its own class around polygon, 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