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Graphics.DrawCurve Method (Pen, PointF(), Single)

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

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

'Declaration
Public Sub DrawCurve ( _
	pen As Pen, _
	points As PointF(), _
	tension As Single _
)

Parameters

pen
Type: System.Drawing.Pen

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

points
Type: System.Drawing.PointF()

Array of PointF structures that represent the points that define the curve.

tension
Type: System.Single

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

ExceptionCondition
ArgumentNullException

pen is Nothing.

-or-

points is Nothing.

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

The array of points must contain at least three PointF 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 Sub DrawCurvePointFTension(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 PointF(50.0F, 50.0F)
    Dim point2 As New PointF(100.0F, 25.0F)
    Dim point3 As New PointF(200.0F, 5.0F)
    Dim point4 As New PointF(250.0F, 50.0F)
    Dim point5 As New PointF(300.0F, 100.0F)
    Dim point6 As New PointF(350.0F, 200.0F)
    Dim point7 As New PointF(250.0F, 250.0F)
    Dim curvePoints As PointF() = {point1, point2, point3, point4, _
    point5, point6, point7}

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

    ' Create tension. 
    Dim tension As Single = 1.0F

    ' Draw curve to screen.
    e.Graphics.DrawCurve(greenPen, curvePoints, tension)
End Sub

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

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

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