Think of new ways to calculate the interpolation ratio

[inadicis]

This ratio defines "how far" in a polygon the spiral went, and is used with an interpolation function, to calculate the color that the current polygon should have.

• iteration ratio: r = Index of current polygon / total_wanted_polygons
  which is easy to implement, but makes the shading depending on how deep in the polygon have to go (the colors will be different if I make it draw 50 recursive polygons or 300).
• perimeter ratio: r = perimeter of current polygon / perimeter of base polygon (Makes it max_iter - independant)
• area ratio: r = area of current polygon / area of base polygon (how to calculate area of custom polygons?)
• radius ratio? (radius being defined as shortest/longest/average length from center to edges/sides) (using center of gravity or centroid for non self intersecting polygons? (see here )