Shrink/Expand the outline of a polygon with holes
问题 I want to expand/shrink a polygon with holes using boost::polygon. So to clarify that a bit, I have a single data structure boost::polygon::polygon_with_holes_data<int> inPoly where inPoly contains data that describe a rectangular outline and a triangle which forms the hole within this rectangle (in picture below this is the left, black drawing). Now I want to a) expand the whole stuff so that the rectangle becomes bigger and the hole becomes smaller (resulting in the red polygon in image