Graphics.DrawClosedCurve Method (Pen, Point[])

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

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

public void DrawClosedCurve (
	Pen pen,
	Point[] points
public void DrawClosedCurve (
	Pen pen, 
	Point[] points
public function DrawClosedCurve (
	pen : Pen, 
	points : Point[]
Not applicable.



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


Array of Point structures that define the spline.

Exception typeCondition


pen is a null reference (Nothing in Visual Basic).


points is a null reference (Nothing in Visual Basic).

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 void DrawClosedCurvePoint(PaintEventArgs e)
    // Create pens.
    Pen redPen   = new Pen(Color.Red, 3);
    Pen greenPen = new Pen(Color.Green, 3);
    // Create points that define curve.
    Point point1 = new Point(50,  50);
    Point point2 = new Point(100,  25);
    Point point3 = new Point(200,   5);
    Point point4 = new Point(250,  50);
    Point point5 = new Point(300, 100);
    Point point6 = new Point(350, 200);
    Point point7 = new Point(250, 250);
    Point[] curvePoints =
    // Draw lines between original points to screen.
    e.Graphics.DrawLines(redPen, curvePoints);
    // Draw closed curve to screen.
    e.Graphics.DrawClosedCurve(greenPen, curvePoints);

Windows 98, Windows Server 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0

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