Trim Curve with Circle

Windows only

Demonstrates how to trim a closed curve with a circle using RhinoScript.

```
Option Explicit
Sub CircleTrimmer
' Local variable declarations
Dim curve, circle, ccx, ccx_t(1), interval
' Select closed curve to split
curve = Rhino.GetObject("Select closed curve to split", 4)
If IsNull(curve) Then Exit Sub
If Not Rhino.IsCurveClosed(curve) Then Exit Sub
' Select circle to split with
circle = Rhino.GetObject("Select circle to split with", 4)
If IsNull(circle) Then Exit Sub
If Not Rhino.IsCircle(circle) Then Exit Sub
' Intersect the two curves
ccx = Rhino.CurveCurveIntersection(curve, circle)
If IsNull(ccx) Then
Rhino.Print "Curve and circle do not intersect"
Exit Sub
End If
' Make sure there are only two intersection events
If UBound(ccx) <> 1 Then
Rhino.Print "Unable to split curve"
Exit Sub
End If
' Get two intersection parameters on the curve
ccx_t(0) = ccx(0,5)
ccx_t(1) = ccx(1,5)
' If the input curve is closed and the interval is decreasing,
' then the portion of the curve across the start and end of the
' curve is returned.
If ccx_t(0) < ccx_t(1) Then
interval = Array(ccx_t(1), ccx_t(0))
Else
interval = Array(ccx_t(0), ccx_t(1))
End If
' Trim the curve
Rhino.TrimCurve curve, interval
End Sub
```