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Graphics.DrawCurve Method (Pen, Point[], Single)

Draws a cardinal spline through a specified array of Point structures using a specified tension.

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

public void DrawCurve(
	Pen pen,
	Point[] points,
	float tension
)

Parameters

pen
Type: System.Drawing.Pen

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

points
Type: System.Drawing.Point[]

Array of Point structures that define the spline.

tension
Type: System.Single

Value greater than or equal to 0.0F that specifies the tension of the curve.

ExceptionCondition
ArgumentNullException

pen is null.

-or-

points is null.

This method draws a cardinal spline that passes through each point in the array.

The array of points must contain at least three Point structures for a curve to be drawn.

The tension parameter determines the shape of the spline. If the value of the tension parameter is 0.0F, this method draws straight line segments to connect the points. Usually, the tension parameter is less than or equal to 1.0F. Values over 1.0F produce unusual results.

The following code example is designed for use with Windows Forms, and it requires PaintEventArgs e, 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 the curve.

  • Draws six red straight lines between the seven points to form an incomplete polygon.

  • Creates a tension setting.

  • Draws an open green closed curve through the seven points.

The method uses a tension of 1.0.

private void DrawCurvePointTension(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 = {point1, point2, point3, point4, point5, point6, point7};

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

    // Create tension. 
    float tension = 1.0F;

    // Draw curve to screen.
    e.Graphics.DrawCurve(greenPen, curvePoints, tension);
}

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0
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