Sort points by angle from given axis?

Question

How can I sort an array of points/vectors by counter-clockwise increasing angle from a given axis vector?

For example:

Answer 1

Most straightforward, but possibly not the optimal way is to shift the cartesian coordinates to be relative to center point and then convert them to polar coordinates. Then just subtract the angle of the "starting vector" modulo 360, and finally sort by angle.

Or, you could make a custom comparator for just handling all the possible slopes and configurations, but I think the polar coordinates are little more transparent.