<Window x:Class="Drawing.ClippingWithViewbox"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="ClippingWithViewbox" Height="335.2" Width="401.6"
    >
  <Window.Resources>
    <GeometryGroup x:Key="clipGeometry" FillRule="Nonzero">
      <EllipseGeometry RadiusX="75" RadiusY="50" Center="100,150"></EllipseGeometry>
      <EllipseGeometry RadiusX="100" RadiusY="25" Center="200,150"></EllipseGeometry>
      <EllipseGeometry RadiusX="75" RadiusY="130" Center="140,140"></EllipseGeometry>
    </GeometryGroup>
  </Window.Resources>
  <Grid>
    <Viewbox >
      <Button Width="350" Height="350" Clip="{StaticResource clipGeometry}">A button</Button>
    </Viewbox>
  </Grid>
</Window>
