Graphics.DrawClosedCurve Method (Pen, Point())


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Draws a closed cardinal spline defined by an array of Point structures.

Namespace:   System.Drawing
Assembly:  System.Drawing (in System.Drawing.dll)

Public Sub DrawClosedCurve (
	pen As Pen,
	points As Point()


Type: System.Drawing.Pen

Pen that determines the color, width, and height of the curve.

Type: System.Drawing.Point()

Array of Point structures that define the spline.

Exception Condition

pen is null.


points is null.

This method draws a closed cardinal spline that passes through each point in the array. If the last point does not match the first point, an additional curve segment is added from the last point to the first point to close the figure.

The array of points must contain at least four Point structures.

This method uses a default tension of 0.5.

The following code example is designed for use with Windows Forms, and it requires PaintEventArgse, which is a parameter of the Paint event handler. The code performs the following actions:

  • Creates red and green pens.

  • Creates seven points to define a curve.

  • Draws seven red straight lines between the seven points to form a closed polygon.

  • Draws a green closed curve through the seven points.

The method uses a default tension of 0.5.

Private Sub DrawClosedCurvePoint(ByVal e As PaintEventArgs)

    ' Create pens.
    Dim redPen As New Pen(Color.Red, 3)
    Dim greenPen As New Pen(Color.Green, 3)

    ' Create points that define curve.
    Dim point1 As New Point(50, 50)
    Dim point2 As New Point(100, 25)
    Dim point3 As New Point(200, 5)
    Dim point4 As New Point(250, 50)
    Dim point5 As New Point(300, 100)
    Dim point6 As New Point(350, 200)
    Dim point7 As New Point(250, 250)
    Dim curvePoints As Point() = {point1, point2, point3, point4, _
    point5, point6, point7}

    ' Draw lines between original points to screen.
    e.Graphics.DrawLines(redPen, curvePoints)

    ' Draw closed curve to screen.
    e.Graphics.DrawClosedCurve(greenPen, curvePoints)
End Sub

.NET Framework
Available since 1.1
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