def angle(a, b):
ax = a.p2.x - a.p1.x
ay = a.p2.y - a.p1.y
bx = b.p2.x - b.p1.x
by = b.p2.y - b.p1.y
dot = e.dot_product(ax, ay, bx, by)
len_a_squared = e.dot_product(ax, ay, ax, ay)
len_b_squared = e.dot_product(bx, by, bx, by)
return e.acos(dot / e.sqrt(len_a_squared * len_b_squared))
def __init__(self, p1, p2):
self.p1 = p1
self.p2 = p2
vx = p1.x - p2.x
vy = p1.y - p2.y
self.length = expressions.sqrt(expressions.dot_product(vx, vy, vx, vy))
super(LineSegment, self).__init__([p1, p2], [])
