Question about __expand_window()

[vascosantos]

Hi!

Thank you for developing and sharing this library. I have been using it quite successfully.

In function __expand_window(), is there a reason for thickening the path with radius before doubling the search window axes rather than the other way around?
This way the search window becomes 4 * radius instead of 2 * radius.

Thanks in advance,
Vasco.