Segment.GetCurvatureAt

Object Model Reference : Classes : S : Segment : Methods : Segment.GetCurvatureAt

Segment.GetCurvatureAt

Function GetCurvatureAt([Offset As Double = 0.5], [OffsetType As cdrSegmentOffsetType = cdrParamSegmentOffset]) As Double

Description

Member of Segment

The GetCurvatureAt method returns a numerical value that indicates the curvature of a segment at a given point. The curvature value is the inverse of the curvature radius and depends on the current document units.


Parameter	Description
Offset	Specifies the offset, in document units, of the point on a segment’s subpath. This parameter is optional, and its default value is 0.5.
OffsetType	Specifies the type of offset. This parameter is optional, and its default value is cdrParamSegmentOffset (2).

VBA example

The following VBA example draws a circle so that it touches the selected curve at the point that represents 25% of its length. This circle has the same curvature as the curve at this point; that is, it shows the curvature radius.

Sub Test()

Dim c As Double, r As Double

Dim x As Double, y As Double, pa As Double

Dim seg As Segment

Set seg = ActiveShape.Curve.Segments(1)

c = seg.GetCurvatureAt(0.25, cdrRelativeSegmentOffset)

If Abs(c) < 0.00001 Then

MsgBox "The segment is almost straight at this point", vbCritical

Exit Sub

End If

seg.GetPointPositionAt x, y, 0.25, cdrRelativeSegmentOffset

pa = seg.GetPerpendicularAt(0.25, cdrRelativeSegmentOffset)

pa = pa * 3.1415926 / 180

r = 1 / c

x = x + r * Cos(pa)

y = y + r * Sin(pa)

ActiveLayer.CreateEllipse2 x, y, r

End Sub