offsetOrNull

Creates an offset version of the input geometry. The offset operation creates a geometry that is a constant distance from the input geometry. It is similar to buffering, but produces a one-sided result. If distance 0, then the offset geometry is constructed to the right of the input geometry, otherwise it is constructed to the left. For a simple polygon, the orientation of outer rings is clockwise and for inner rings it is counterclockwise. So the "right side" of a simple polygon is always its inside. The bevelRatio is multiplied by the offset distance and the result determines how far a mitered offset intersection can be from the input curve before it is beveled.