<DataSource ID="Gradient">
    <fields>
        <field name="ref" type="identifier" xmlAttribute="true" title="Identifier"/>
        <field name="id"  type="string"/>
        <field name="colorStops"  type="ColorStop" multiple="true" />
        <field name="startColor" type="color"/>
        <field name="endColor"  type="color"/>
    </fields>
</DataSource>
