How to programmatically calculate colliders for sprites?

Question

Algorithms

The pictures show examples of spritelists with rendered round colliders given as the coordinates of the circle's center and its radius.

spritelists

The green circle is the visible cillider, the others are the hit cillider.

Who has any ideas how to programmatically analyze the sprite to calculate such colliders?

Answer 1

There is a family of algorithms called Convex Hulling that allows you to wrap an image into a primitive with the required accuracy.
The resulting primitive contour can already be used for filling with colliders, also with the required accuracy.
To fill a primitive with colliders, an algorithm from the Bin Packing family may be suitable . They allow you to take into account the overlap and inaccuracy of filling the contour.
As a result, when selecting implementations and adjusting the criteria, you can get a result comparable to those shown in the images.
However, personally, I would recommend stopping at the outline of the image primitive. If these are all really colliders, then testing a single closed polygon would be cheaper than testing a potentially infinite collection of circles.