code: public void subtract (Area area) {
          if (area == null || isEmpty() || area.isEmpty()) {
              return;
          }
  
          if (isPolygonal() && area.isPolygonal()) {
              subtractPolygon(area);
          } else {
              subtractCurvePolygon(area);
          }
  
          if (areaBoundsSquare() < GeometryUtil.EPSILON) {
              reset();
          }
      }
docs: Subtracts the supplied area from this area.