calculate intermediate Polygon from two given ones

The need is to make the algorithm to calculate an intermediate Polygon between 2 given Polygons. Some details: - Center point is given. - We need to calculate the intermediate polygon given a proportion. For example '1/2' will calculate the polygon in the very middle between the other 2, '1/3' the polygon closer to the 1st polygon, etc - The given polygons can be composed of multiple polygons on their own (usually a big main polygon and possibly small ones around it). Visual example attached. Possible strategies I thought (just an idea maybe you have a better one): 1) Detect which polygon has more vertices, iterate all around it to get rid of vertices of smallest lines until the vertices in both polygons become the same. Calculate the point within the line connecting each individual vertex of the 2 polygons 2) Calculate a line between each vertex of the biggest polygon to the center. Calculate the intersection point between that line and the small polygon. Calculate the point within the new line formed from the intersection point and the vertex of the big polygon (do the same for each vertex).