How does this code work?

The purpose of the code is to find the distance from a point to the nearest point on a line segment. It works, but I dont quite understand whats going on or how linear interpolation (I think thats what lerp means?) works or applies here. Self is a line represented by its two end points.

def sq_shortest_dist_to_point(self, other_point): dx = self.b.x - self.a.x dy = self.b.y - self.a.y dr2 = float(dx ** 2 + dy ** 2) lerp = ((other_point.x - self.a.x) * dx + (other_point.y - self.a.y) * dy) / dr2 if lerp < 0: lerp = 0 elif lerp > 1: lerp = 1 x = lerp * dx + self.a.x y = lerp * dy + self.a.y _dx = x - other_point.x _dy = y - other_point.y square_dist = _dx ** 2 + _dy ** 2 return square_dist def shortest_dist_to_point(self, other_point): return math.sqrt(self.sq_shortest_dist_to_point(other_point)) 

Someone flagged this as needing more info but did not say what information they needed. I have included everything the only parameters are self and other_point theres no use of outside defined variables or anything like that Im not sure what info you want. As stated above ^ "Self is a line represented by its two end points." so self A and self B are the endpoints each with a (x,y).

other_point is also (x,y). Genuinely dont know how to add more information