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/impl/AttributeFactoryImpl.java
* <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @generated
	 */
	public Location createLocation( )
	{
		LocationImpl location = new LocationImpl( );
		return location;
	}
	/**
	 * <!-- begin-user-doc -->
	 * <!-- end-user-doc -->
	 * @generated
	 */
	public Location3D createLocation3D( )
	{
		Location3DImpl location3D = new Location3DImpl( );
		return location3D;
	}
	/**
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @generated
	 */
	public Marker createMarker( )
	{
		MarkerImpl marker = new MarkerImpl( );
		return marker;
	}
	/**
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @generated