class FindIntersections():
def __init__(self):
self.Q = EventQueue()
self.T = StatusStructure()
self.intersections = []
def find_intersections(self, lines):
for line in lines:
self.Q.insert_line(line)
while not self.Q.is_empty():
next_event = self.Q.pop_next_event()
self.handle_event_point(next_event)
def handle_event_point(self, p):
U_p = p.lines
L_p, C_p, L_C = self.T.find_segments_contain(p.point)
U_C = U_p + C_p
L_U_C = L_C + U_p
if len(L_U_C) > 1:
self.intersections.append(p.point)
for line in L_C:
self.T.delete(p.point, line)
self.T.insert(p.point, U_C)
self.T._print_name()
if len(U_C) == 0:
s_l = self.T.find_left_neighbor(p.point)
s_r = self.T.find_right_neighbor(p.point)
self.find_new_event(s_l, s_r, p.point)
else:
s_lm = self.T.find_leftmost(p.point)
s_l = self.T.find_left_neighbor(p.point)
self.find_new_event(s_lm, s_l, p.point)
s_rm = self.T.find_rightmost(p.point)
s_r = self.T.find_right_neighbor(p.point)
self.find_new_event(s_rm, s_r, p.point)
def find_new_event(self, s_l, s_r, p):
if s_l is None or s_r is None:
return
i = s_l.intersect(s_r)
if i is None:
return
x_i, y_i = i
x_p, y_p = p
if y_i < y_p or (y_i == y_p and x_i > x_p):
self.Q.insert(i)
