多段线与数学

Function RadiusFromBulge(Bulge As Double, pt1, pt2) As Double
    Dim Dist As Double, Rad As Double
    Dist = 0.5 * Length(pt1, pt2)
    RadiusFromBulge = Abs(Dist / Sin(Atn(Bulge) * 2))
End Function

Public Function CenterFromBulge(P1, P2, Bulge As Double)
    
    If UBound(P1) = 1 Then
        ReDim Preserve P1(2)
    End If
    If UBound(P2) = 1 Then
        ReDim Preserve P2(2)
    End If
    Dim Ang As Double, CenPt(2) As Double
    Dim Rad As Double, Dist As Double
    Dist = Length(P1, P2) 'Use your length function
    Rad = Abs(0.5 * Dist / Sin(Atn(Bulge) * 2))
    Ang = ThisDrawing.Utility.AngleFromXAxis(P1, P2)
    If Bulge > 0 Then
        Ang = Ang + ((0.5 * pi) - (Atn(Bulge) * 2))
    Else
        Ang = Ang - ((0.5 * pi) + (Atn(Bulge) * 2))
    End If
    CenPt(0) = P1(0) + Cos(Ang) * Rad
    CenPt(1) = P1(1) + Sin(Ang) * Rad
    CenPt(2) = 0
    CenterFromBulge = CenPt
 
End Function

Public Function Length(StartPoint As Variant, EndPoint As Variant) As Double
    Dim Stx As Double, Sty As Double, Stz As Double
    Dim Enx As Double, Eny As Double, Enz As Double
    Dim dX As Double, dY As Double, Dz As Double
    Dim i As Integer
    If IsEmpty(StartPoint) Then Err.Raise 13
    i = UBound(StartPoint)
    If UBound(EndPoint) = i Then
        If i > 0 Then
            Stx = StartPoint(0): Sty = StartPoint(1)
            Enx = EndPoint(0): Eny = EndPoint(1)
            dX = Stx - Enx
            dY = Sty - Eny
            If i = 1 Then
                Length = Sqr(dX * dX + dY * dY)
            Else
                Stz = StartPoint(2): Enz = EndPoint(2)
                Dz = Stz - Enz
                Length = Sqr((dX * dX) + (dY * dY) + (Dz * Dz))
            End If
        Else
            Exit Function
        End If
    Else
        Exit Function
    End If
End Function

Public Function CenterFromBulge(oPline As AcadLWPolyline, index As Integer) As Variant
    If oPline Is Nothing Then Exit Function
    If (UBound(oPline.Coordinates) - 1) / 2  0 Then
        If Bulge > 1 Then
            Ang = Ang - ((0.5 * pi) - (pi - BulgeAng))
        Else
            Ang = Ang + ((0.5 * pi) - BulgeAng)
        End If
    Else
        If Bulge  0 Then
            dAng = 0
        Else
            dAng = pi '180
        End If
    ElseIf Rd(dX, 0) Then  'Line is vertical
        If dY > 0 Then
            dAng = 0.5 * pi '90
        Else
            dAng = 1.5 * pi '270
        End If
    Else
        dAng = Atn(dY / dX)
        If dAng 270
            If dX 270
                dAng = pi + dAng '90->180
            Else '270->360
                dAng = 2 * pi + dAng
            End If
        Else
            If dX 270
                dAng = pi + dAng
            End If
        End If
    End If
    AngFromX = dAng
End Function
Function Rd(num1 As Variant, num2 As Variant) As Boolean
    Dim dRet As Double
    dRet = num1 - num2
    If Abs(dRet) < 0.00000001 Then Rd = True
End Function