'计算夹角函数 `qZ@eGZ
z
Function ff_angle(x1 As Single, y1 As Single, x2 As Single, y2 As Single, x3 As Single, y3 As Single) As Single GB>T3l"
cax = x2 - x1 $cLZ,N24
cay = y2 - y1 ZJ[p7XP
cbx = x2 - x3 k\ZU%"^J
cby = y2 - y3 -cUw}
mo_jj = cax * cbx + cay * cby '[bw7T
mo_ca = Sqr(cax * cax + cay * cay) 5 L-6@@/
mo_cb = Sqr(cbx * cbx + cby * cby) y@Td]6|f
cos_acb = mo_jj / (mo_ca * mo_cb) [kPl7[OL
'ff_cos = cos_acb w2K>k/v{-
If cos_acb >= 1 Then Ev48|X6
nn = 0 [&zSY