1.由点转换得到向量

2.由向量计算夹角

参考文档：https://www.jb51.net/article/164697.htm

 

import math 
#A(1,-3)B(5,-1)C(4,1)D(4.5,4.5)
#AB = [1,-3,5,-1]
AB = [5,-1,1,-3]
CD = [4,1,4.5,4.5]

def angle(v1, v2):
  dx1 = v1[2] - v1[0]
  dy1 = v1[3] - v1[1]
  dx2 = v2[2] - v2[0]
  dy2 = v2[3] - v2[1]
  angle1 = math.atan2(dy1, dx1)
  angle1 = int(angle1 * 180/math.pi)
  # print(angle1)
  angle2 = math.atan2(dy2, dx2)
  angle2 = int(angle2 * 180/math.pi)
  # print(angle2)
  if angle1*angle2 >= 0:
    included_angle = abs(angle1-angle2)
  else:
    included_angle = abs(angle1) + abs(angle2)
    if included_angle > 180:
      included_angle = 360 - included_angle
  return included_angle
 
ang1 = angle(AB, CD)
print("AB和CD的夹角")
print(ang1)