No Something like this
<Rectangle Width="13" Height="13" Fill="{Binding Foreground, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Button}}}">
<Rectangle.OpacityMask>
<VisualBrush Stretch="Fill" Visual="{DynamicResource appbar_smiley_grin}" />
</Rectangle.OpacityMask>
</Rectangle>