ElipseControl.xaml

<UserControl x:Class="R722ControlWPFEnWinForms.ElipseControl"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             Height="300" Width="300">
    <Grid x:Name="grdPrincipal">
        <Grid.Resources>
            <RadialGradientBrush x:Key="Rojo" RadiusX=".8" RadiusY="1"
                                 Center="0.5,0.5" GradientOrigin="0.05,0.5">
                <GradientStop Color="#ffffff" Offset="0.1" />
                <GradientStop Color="#ff0000" Offset="0.5" />
                <GradientStop Color="#880000" Offset="0.8" />
            </RadialGradientBrush>
            <RadialGradientBrush x:Key="Azul" RadiusX=".8" RadiusY="1"
                                 Center="0.5,0.5" GradientOrigin="0.05,0.5">
                <GradientStop Color="#ffffff" Offset="0.1" />
                <GradientStop Color="#0000ff" Offset="0.5" />
                <GradientStop Color="#000088" Offset="0.8" />
            </RadialGradientBrush>
        </Grid.Resources>
        <Ellipse Margin="5" Name="Elipse" ToolTip="Elipse en WPF."
                 Fill="{StaticResource Rojo}">
        </Ellipse>
    </Grid>
</UserControl>