'計算夾角函數(shù) B4kIcHA
Function ff_angle(x1 As Single, y1 As Single, x2 As Single, y2 As Single, x3 As Single, y3 As Single) As Single b#sO1MXv
cax = x2 - x1 {?8rvAjY
cay = y2 - y1 B-RaAiE@
cbx = x2 - x3 =6Z1yw7s
cby = y2 - y3 8:f(PN
mo_jj = cax * cbx + cay * cby u%FA.
mo_ca = Sqr(cax * cax + cay * cay) hYLu
mo_cb = Sqr(cbx * cbx + cby * cby) fA8 ,wy|>
cos_acb = mo_jj / (mo_ca * mo_cb) s
SDBl~g
'ff_cos = cos_acb ?IK[]=!
If cos_acb >= 1 Then %n^]1R#
nn = 0 y=t
-/*K
ElseIf cos_acb <= -1 Then k@?<Aw8_X
nn = 3.14159265258979 L(.5:&Y=`
Else ]]+"`t,-
nn = Atn(-cos_acb / Sqr(-cos_acb * cos_acb + 1)) + 2 * Atn(1) 2'D2>^os
End If >">-4L17m
'ff_angle = nn ;yr'K
ff_angle = nn * 180 / 3.14159265258979 +U[A.^t
End Function