[求助]过一点做直线的垂线？

dyheng

已知一直线和直线上的一点，有什么简单的方法能过该点作出已知直线的垂线？望高手能予指教

cbse_smy

这个问题我想可以这样处理，应用直线方程，点截式，先计算已知直线斜率，那么垂线的斜率必然与之相差９０度，然后直线过一点以及它也的斜率便可得出直线来！

yulijin608

直线都有个Angle属性，是直线的倾斜角度（从X轴按逆时针转动）

ljpnb

这样行吗？

2. Sub test()
3. Dim lineobj1 As AcadLine
4. Dim lineobj2 As AcadLine
5. Dim pnt1 As Variant
6. Dim ang As Double
7. Dim pi As Double
8. pi = 4 * Atn(1)
9. ThisDrawing.Utility.GetEntity lineobj1, pnt, "select a line:"
10. ang = pi * 0.5
11. pnt1 = ThisDrawing.Utility.GetPoint(, "select a point:")
12. Set lineobj2 = lineobj1.Copy()
13. lineobj2.Rotate pnt1, ang
14. End Sub

Sub test() Dim lineobj1 As AcadLine Dim lineobj2 As AcadLine Dim pnt1 As Variant Dim ang As Double Dim pi As Double pi = 4 * Atn(1) ThisDrawing.Utility.GetEntity lineobj1, pnt, "select a line:" ang = pi * 0.5 pnt1 = ThisDrawing.Utility.GetPoint(, "select a point:") Set lineobj2 = lineobj1.Copy() lineobj2.Rotate pnt1, ang End Sub