[Athanasios Gardos]

Option Explicit

Dim oMath As Object

Private Sub Command2_Click()
	cAvax1.Command = Zoom_c
End Sub

Private Sub Command3_Click()
	cAvax1.Command = Previous_c
End Sub

Private Sub Command1_Click()
	Dim h() As Long
	Dim lMax As Long
	Dim lCnt As Long
	Dim x1 As Single, y1 As Single, z1 As Single
	Dim x2 As Single, y2 As Single, z2 As Single
	Dim xc As Single, yc As Single, zc As Single
	Dim R As Single
	lMax = cAvax1.GetSelectedHandlesArr(h())
	If lMax = 0 Then
	   MsgBox "Please, select an object first."
	Else
	   For lCnt = 1 To lMax
		   If IsArc(h(lCnt), x1, y1, z1, x2, y2, z2, xc, yc, zc, R) = True Then
			  MsgBox "Yes, it is an Arc" & vbCrLf & x1 & "," & y1 & "," & z1 & vbCrLf & x2 & "," & y2 & "," & z2 & vbCrLf & xc & "," & yc & "," & zc & vbCrLf & "R=" & R, vbInformation, "(" & h(lCnt) & ")"
		   Else
			  MsgBox "No, it is not an Arc", vbInformation, "(" & h(lCnt) & ")"
		   End If
	   Next lCnt
	End If
End Sub

Private Function IsArc(avHandle As Long, x1 As Single, y1 As Single, z1 As Single, x2 As Single, y2 As Single, z2 As Single, xArcC As Single, yArcC As Single, zArcC As Single, R As Single) As Boolean
	Dim h() As Long, iType() As AvaxItemType, vProp() As Variant
	Dim vData() As Variant, xyz() As Single, vCount As Long, v1 As Long
	Dim xa1 As Single, ya1 As Single, za1 As Single
	Dim xa2 As Single, ya2 As Single, za2 As Single
	Dim xb1 As Single, yb1 As Single, zb1 As Single
	Dim xb2 As Single, yb2 As Single, zb2 As Single
	Dim xc As Single, yc As Single, zc As Single, dn As Integer
	Dim xcOld As Single, ycOld As Single, zcOld As Single, Angle As Single
	Dim xc11 As Single, yc11 As Single
	Dim xc21 As Single, yc21 As Single
	Dim xc12 As Single, yc12 As Single
	Dim xc22 As Single, yc22 As Single
	Dim R1 As Single
	ReDim h(1) As Long
	h(1) = avHandle
	If cAvax1.GetProperties(h(), iType(), vProp(), vData()) = True Then
	   If iType(1) = Polyline_i Then
		  xyz() = vData(1)
		  vCount = UBound(xyz()) / 6
		  If vCount > 1 Then
			 If oMath.IsSamePoint(xyz(1), xyz(2), xyz((vCount - 1) * 6 + 4), xyz((vCount - 1) * 6 + 5)) = True Then Exit Function
			 For v1 = 1 To vCount - 1
				 xa1 = xyz((v1 - 1) * 6 + 1)
				 ya1 = xyz((v1 - 1) * 6 + 2)
				 za1 = xyz((v1 - 1) * 6 + 3)
				 xa2 = xyz((v1 - 1) * 6 + 4)
				 ya2 = xyz((v1 - 1) * 6 + 5)
				 za2 = xyz((v1 - 1) * 6 + 6)
				 Call oMath.LineCenter(xa1, ya1, xa2, ya2, xc11, yc11)
				 Call oMath.LineInclination(xa2, ya2, xa1, ya1, Angle)
				 Call oMath.PolarPoint(xc11, yc11, 5, Angle + 90, xc12, yc12)
				 xb1 = xyz(v1 * 6 + 1)
				 yb1 = xyz(v1 * 6 + 2)
				 zb1 = xyz(v1 * 6 + 3)
				 xb2 = xyz(v1 * 6 + 4)
				 yb2 = xyz(v1 * 6 + 5)
				 zb2 = xyz(v1 * 6 + 6)
				 Call oMath.LineCenter(xb1, yb1, xb2, yb2, xc21, yc21)
				 Call oMath.LineInclination(xb2, yb2, xb1, yb1, Angle)
				 Call oMath.PolarPoint(xc21, yc21, 5, Angle + 90, xc22, yc22)
				 dn = 0
				 Call oMath.InterSectLines(xc11, yc11, xc12, yc12, xc21, yc21, xc22, yc22, xc, yc, dn)
				 If dn = 0 Then Exit Function
				 If v1 = 1 Then
					x1 = xa2
					y1 = ya2
					z1 = za2
					xcOld = xc
					ycOld = yc
					zc = za1
				 Else
					If oMath.IsSamePoint(xcOld, ycOld, xc, yc) = False Then
					   Exit Function
					Else
					   Call oMath.Distance(xa1, ya1, xc, yc, R1)
					   If R1 > R Then R = R1: xcOld = xc: ycOld = yc
					   Call oMath.Distance(xb1, yb1, xc, yc, R1)
					   If R1 > R Then R = R1: xcOld = xc: ycOld = yc
					   x2 = xb1
					   y2 = yb1
					   z2 = zb1
					End If
				 End If
			 Next v1
			 xArcC = xcOld
			 yArcC = ycOld
			 zArcC = zc
			 Call oMath.LineCenter(x1, y1, x2, y2, xc11, yc11)
			 Call oMath.LineInclination(x2, y2, x1, y1, Angle)
			 Call oMath.PolarPoint(xc11, yc11, 5, Angle + 90, xc12, yc12)
			 dn = 0
			 Call oMath.InterSectLines(x1, y1, xcOld, ycOld, xc11, yc11, xc12, yc12, xc, yc, dn)
			 If dn = 0 Then Exit Function
			 xArcC = xc
			 yArcC = yc
			 Call oMath.Distance(x1, y1, xc, yc, R)
			 IsArc = True
		  End If
	   End If
	End If
End Function

Private Sub Form_Load()
	Command1.Caption = "Is it an Arc ?"
	Command2.Caption = "zoom"
	Command3.Caption = "previous"
	Set oMath = CreateObject("avMath.cAvaxMath")
	cAvax1.StartAvax
	Call cAvax1.Add_Arc(0, 1, 0, 1, 0, 0, 0, 0, 0, , 1)
	Call cAvax1.Add_Arc(1, 0, 0, 0, 1, 0, 0, 0, 0, , 3)
	Call cAvax1.Add_Line(0, 0, 0, 1, 0, 0)
	Call cAvax1.Add_Line(0, 0, 0, 0, 1, 0)
	Call cAvax1.Add_Rectangle(-1, -1, 2, 2)
	cAvax1.Command = AutoLimits_c
End Sub

Private Sub Form_Unload(Cancel As Integer)
	Set oMath = Nothing
	cAvax1.EndAvax
End Sub

[Crystallyne]

Unfortunately, this code does not seem to work for us. Most of the arcs we see in the drawing (which have come from .DXF) are identified as polylines not as arcs. This is because for some reason, the point values returned by Avax for (Xcold,ycold) and (xc,yc) will vary in accuracy, sometimes being returned at 4 decimals, others at 8. Also, they may be equal to as little as the 2nd decimal place or as much as the 6th. This results in (xcold,ycold) rarely being equal to (xc,yc) so the test fails.

We see this point accuracy problem occur occasionally elsewhere as well but because it is so small a difference it is not usually a problem. For instance, we will draw a radius of 1" and when measured by points later it will come back as a number like .99974 . We are using Vb.Net and do have the most current version of Avax.

Is there any way to correct this without rounding to a very small number of places?

Thanks,
Chris