'计算夹角函数 +X[+SF)!
Function ff_angle(x1 As Single, y1 As Single, x2 As Single, y2 As Single, x3 As Single, y3 As Single) As Single [JAHPy=+w
cax = x2 - x1 Ewjzm,2
cay = y2 - y1 hLYy
cbx = x2 - x3 W[trsFP1?
cby = y2 - y3 k
I{)"
mo_jj = cax * cbx + cay * cby )!+M\fT
mo_ca = Sqr(cax * cax + cay * cay) 6H+'ezM
mo_cb = Sqr(cbx * cbx + cby * cby) 9Q{-4yF9k
cos_acb = mo_jj / (mo_ca * mo_cb) npsDy&