Ellipse.OpacityMask
<Canvas xmlns="http://schemas.microsoft.com/client/2007" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Width="200" Height="200"> <Ellipse Canvas.Left="5" Canvas.Top="5" Canvas.ZIndex="1" Height="200" Width="200" Stroke="Black" StrokeThickness="10" Fill="Silver"> <Ellipse.OpacityMask> <LinearGradientBrush> <GradientStop Offset="0.25" Color="#00000000"/> <GradientStop Offset="1" Color="#FF000000"/> </LinearGradientBrush> </Ellipse.OpacityMask> </Ellipse> <Ellipse Canvas.Left="50" Canvas.Top="50" Canvas.ZIndex="3" Height="200" Width="200" Stroke="Black" StrokeThickness="10"> <Ellipse.Fill> <LinearGradientBrush> <GradientStop Offset="0.00" Color="#ffffff"/> <GradientStop Offset="1.00" Color="DeepSkyBlue"/> </LinearGradientBrush> </Ellipse.Fill> </Ellipse> <Ellipse Canvas.Left="95" Canvas.Top="95" Canvas.ZIndex="2" Height="200" Width="200" Stroke="Black" StrokeThickness="10" Fill="Lime" /> </Canvas>