PathGradientBrush.SetSigmaBellShape Method

Definition

Namespace:

System.Drawing.Drawing2D

Assembly:

System.Drawing.Common.dll

Creates a gradient falloff between the center color and the first surrounding color based on a bell-shaped curve.

Overloads

SetSigmaBellShape(Single)	Creates a gradient brush that changes color starting from the center of the path outward to the path's boundary. The transition from one color to another is based on a bell-shaped curve.
SetSigmaBellShape(Single, Single)	Creates a gradient brush that changes color starting from the center of the path outward to the path's boundary. The transition from one color to another is based on a bell-shaped curve.

SetSigmaBellShape(Single)

Creates a gradient brush that changes color starting from the center of the path outward to the path's boundary. The transition from one color to another is based on a bell-shaped curve.

public:
 void SetSigmaBellShape(float focus);

public void SetSigmaBellShape (float focus);

member this.SetSigmaBellShape : single -> unit

Public Sub SetSigmaBellShape (focus As Single)

Parameters

focus

Single

A value from 0 through 1 that specifies where, along any radial from the center of the path to the path's boundary, the center color will be at its highest intensity. A value of 1 (the default) places the highest intensity at the center of the path.

Examples

For an example, see SetSigmaBellShape.

Remarks

If there is more than one color in the SurroundColors array, the first color in the array is used for the ending color. The colors specified in this array are colors used for discrete points on the brush's boundary path.

By default, as you move from the boundary of a path gradient to the center point, the color changes gradually from the boundary color to the center color. You can customize the positioning and blending of the boundary and center colors by calling this method.

SetSigmaBellShape(Single, Single)

Creates a gradient brush that changes color starting from the center of the path outward to the path's boundary. The transition from one color to another is based on a bell-shaped curve.

public:
 void SetSigmaBellShape(float focus, float scale);

public void SetSigmaBellShape (float focus, float scale);

member this.SetSigmaBellShape : single * single -> unit

Public Sub SetSigmaBellShape (focus As Single, scale As Single)

Parameters

focus

Single

A value from 0 through 1 that specifies where, along any radial from the center of the path to the path's boundary, the center color will be at its highest intensity. A value of 1 (the default) places the highest intensity at the center of the path.

scale

Single

A value from 0 through 1 that specifies the maximum intensity of the center color that gets blended with the boundary color. A value of 1 causes the highest possible intensity of the center color, and it is the default value.

Examples

The following code example is designed for use with Windows Forms, and it requires PaintEventArgs e, an OnPaint event object. The code performs the following actions:

• Creates a graphics path and adds a rectangle to it.

• Creates a PathGradientBrush from the path points (in this example, the points form a rectangle, but it could be most any shape).

• Sets the center color to red and the surrounding color to blue.

• Draws the PathGradientBrush to the screen prior to applying the blend transform.

• Applies the blend transform to the brush by using its SetSigmaBellShape method.

• Calls the TranslateTransform method to move the brush rectangle such that it does not overlay the one drawn to the screen earlier.

• Draws the transformed-brush rectangle to the screen.

Notice that the maximum center color (red) is located half way from the center of the path to the path boundary.

public:
   void SetSigmaBellShapeExample( PaintEventArgs^ e )
   {
      // Create a graphics path and add a rectangle.
      GraphicsPath^ myPath = gcnew GraphicsPath;
      Rectangle rect = Rectangle(100,20,100,50);
      myPath->AddRectangle( rect );

      // Get the path's array of points.
      array<PointF>^myPathPointArray = myPath->PathPoints;

      // Create a path gradient brush.
      PathGradientBrush^ myPGBrush = gcnew PathGradientBrush( myPathPointArray );

      // Set the color span.
      myPGBrush->CenterColor = Color::Red;
      array<Color>^ mySurroundColor = {Color::Blue};
      myPGBrush->SurroundColors = mySurroundColor;

      // Draw the brush to the screen prior to blend.
      e->Graphics->FillRectangle( myPGBrush, 10, 10, 200, 200 );

      // Set the Blend factors and transform the brush.
      myPGBrush->SetSigmaBellShape( 0.5f, 1.0f );

      // Move the brush down by 100 by applying the translate
      // transform to the brush.
      myPGBrush->TranslateTransform( 0, 100, MatrixOrder::Append );

      // Draw the brush to the screen again after setting the
      // blend and applying the transform.
      e->Graphics->FillRectangle( myPGBrush, 10, 10, 300, 300 );
   }

public void SetSigmaBellShapeExample(PaintEventArgs e)
{
             
    // Create a graphics path and add a rectangle.
    GraphicsPath myPath = new GraphicsPath();
    Rectangle rect = new Rectangle(100, 20, 100, 50);
    myPath.AddRectangle(rect);
             
    // Get the path's array of points.
    PointF[] myPathPointArray = myPath.PathPoints;
             
    // Create a path gradient brush.
    PathGradientBrush myPGBrush = new
        PathGradientBrush(myPathPointArray);
             
    // Set the color span.
    myPGBrush.CenterColor = Color.Red;
    Color[] mySurroundColor = {Color.Blue};
    myPGBrush.SurroundColors = mySurroundColor;
             
    // Draw the brush to the screen prior to blend.
    e.Graphics.FillRectangle(myPGBrush, 10, 10, 200, 200);
             
    // Set the Blend factors and transform the brush.
    myPGBrush.SetSigmaBellShape(0.5f, 1.0f);
             
    // Move the brush down by 100 by applying the translate
    // transform to the brush.
    myPGBrush.TranslateTransform(0, 100, MatrixOrder.Append);
             
    // Draw the brush to the screen again after setting the
    // blend and applying the transform.
    e.Graphics.FillRectangle(myPGBrush, 10, 10, 300, 300);
}

Public Sub SetSigmaBellShapeExample(ByVal e As PaintEventArgs)

    ' Create a graphics path and add a rectangle.
    Dim myPath As New GraphicsPath
    Dim rect As New Rectangle(100, 20, 100, 50)
    myPath.AddRectangle(rect)

    ' Get the path's array of points.
    Dim myPathPointArray As PointF() = myPath.PathPoints

    ' Create a path gradient brush.
    Dim myPGBrush As New PathGradientBrush(myPathPointArray)

    ' Set the color span.
    myPGBrush.CenterColor = Color.Red
    Dim mySurroundColor As Color() = {Color.Blue}
    myPGBrush.SurroundColors = mySurroundColor

    ' Draw the brush to the screen prior to blend.
    e.Graphics.FillRectangle(myPGBrush, 10, 10, 200, 200)

    ' Set the Blend factors.
    myPGBrush.SetSigmaBellShape(0.5F, 1.0F)

    ' Move the brush down by 100 by applying the translate
    ' transform to the brush.
    myPGBrush.TranslateTransform(0, 100, MatrixOrder.Append)

    ' Draw the brush to the screen again after setting the
    ' blend and applying the transform.
    e.Graphics.FillRectangle(myPGBrush, 10, 10, 300, 300)
End Sub

Remarks

If there is more than one color in the SurroundColors array, the first color in the array is used for the ending color. The colors specified in this array are colors used for discrete points on the brush's boundary path.

By default, as you move from the boundary of a path gradient to the center point, the color changes gradually from the boundary color to the center color. You can customize the positioning and blending of the boundary and center colors by calling this method.