两条直线是否相交

这个比较简单,各直线直接取2点 ,计算斜率!只有相等才是平行(这里是在一个平面)

下面是VB代码,计算的是正切 (TAN)

 

Option Explicit
Const xx As Double = 0.0000001
Private Sub Command1_Click()
    MsgBox IsConnect(Line1, Line2)
End Sub

Public Function IsConnect(Line1 As Line, Line2 As Line) As Boolean
    IsConnect = False

    Dim Rate1 As Double
    Dim Rate2 As Double
    If Line1.X2 = Line1.X1 Then
        Rate1 = 0
    Else
        Rate1 = (Line1.Y2 - Line1.Y1) / (Line1.X2 - Line1.X1)
    End If

    If Line2.X2 = Line2.X1 Then
        Rate2 = 0
    Else
        Rate2 = (Line2.Y2 - Line2.Y1) / (Line2.X2 - Line2.X1)
    End If

    If Abs(Rate1 - Rate2) > xx Then
        IsConnect = True
    Else
        IsConnect = False
    End If
End Function