<DataSource ID="DrawDiamond" inheritsFrom="DrawItem" Constructor="DrawDiamond" >
    <fields>
        <field name="left" type="integer" title="Left" defaultValue="0"/>
        <field name="top" type="integer" title="Top" defaultValue="0"/>
        <field name="width" type="integer" title="Width" defaultValue="100"/>
        <field name="height" type="integer" title="Height" defaultValue="100"/>
    </fields>
</DataSource>
