Bug 104986 Backgound image uses an absolute path
Currently Chart uses an absolute path to indicate a backgournd image, that may cause the design unusable on other environments. Expected the background image can be definded in multiple ways like in report designer. e.g. URI(absolute path), File(relative path), Embedded Image(Encoded Image Data).
chart/org.eclipse.birt.chart.engine/src/org/eclipse/birt/chart/model/attribute/util/AttributeAdapterFactory.java
* Creates an instance of the adapter factory.
	 * <!-- begin-user-doc --> <!--
	 * end-user-doc -->
	 * @generated
	 */
	public AttributeAdapterFactory( )
	{
		if ( modelPackage == null )
		{
			modelPackage = AttributePackage.eINSTANCE;
		}
	}
	/**
	 * Returns whether this factory is applicable for the type of the object.
	 * <!-- begin-user-doc --> This implementation returns <code>true</code>
	 * if the object is either the model's package or is an instance object of
	 * the model. <!-- end-user-doc -->
	 * @return whether this factory is applicable for the type of the object.
	 * @generated
	 */
	public boolean isFactoryForType( Object object )
	{
		if ( object == modelPackage )
		{
			return true;
		}
		if ( object instanceof EObject )
		{
			return ( (EObject) object ).eClass( ).getEPackage( ) == modelPackage;
		}