The RadialGradientBrush is similar in programming model to the LinearGradientBrush. However, the linear gradient has a start and an end point to define the gradient vector, while the radial gradient has a circle, along with a focal point, to define the gradient behavior. The circle defines the end point of the gradient. In other words, a gradient stop at 1.0 defines the color at the circle's circumference. The focal point defines the center of the gradient. A gradient stop at 0.0 defines the color at the focal point.

The following image shows a rectangle filled with a radial gradient. The radial gradient that goes from white to gray. The outside circle represents the gradient circle while the red dot denotes the focal point. This gradient has its SpreadMethod set to Pad.

Note:
RadialGradientBrush objects are rendered using hardware acceleration on Tier 2 systems. For more information about hardware tiers, see Graphics Rendering Tiers.

Freezable Features

This example shows how to use the RadialGradientBrush class to paint an area with a radial gradient.

The following example uses a RadialGradientBrush to paint a rectangle with a radial gradient that transitions from yellow to red to blue to lime green.

<Page 
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  Title="RadialGradientBrush Example"
  Background="White" Margin="20">
  <StackPanel>

    <!-- This rectangle is painted with a radial gradient. -->
    <Rectangle Width="200" Height="100">
      <Rectangle.Fill>
        <RadialGradientBrush 
          GradientOrigin="0.5,0.5" 
          Center="0.5,0.5" RadiusX="0.5" RadiusY="0.5">
          <RadialGradientBrush.GradientStops>
            <GradientStop Color="Yellow" Offset="0" />
            <GradientStop Color="Red" Offset="0.25" />
            <GradientStop Color="Blue" Offset="0.75" />
            <GradientStop Color="LimeGreen" Offset="1" />
          </RadialGradientBrush.GradientStops>
        </RadialGradientBrush>
      </Rectangle.Fill>
    </Rectangle>
  </StackPanel>
</Page>

The following illustration shows the gradient from the preceding example. The gradient's stops have been highlighted.

Note:

The examples in this topic use the default coordinate system for setting control points . The default coordinate system is relative to a bounding box: 0 indicates 0 percent of the bounding box , and 1 indicates 100 percent of the bounding box. You can change this coordinate system by setting the MappingMode property to the value Absolute. An absolute coordinate system is not relative to a bounding box. Values are interpreted directly in local space.

For additional RadialGradientBrush examples, see the Brushes Sample. For more information about gradients and other types of brushes, see Painting with Solid Colors and Gradients Overview.

Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003

.NET Framework

Reference

Other Resources