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 TextAlignment createTextAlignment( )
	{
		TextAlignmentImpl textAlignment = new TextAlignmentImpl( );
		return textAlignment;
	}
	/**
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @generated
	 */
	public TooltipValue createTooltipValue( )
	{
		TooltipValueImpl tooltipValue = new TooltipValueImpl( );
		return tooltipValue;
	}
	/**
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @generated
	 */
	public URLValue createURLValue( )
	{
		URLValueImpl urlValue = new URLValueImpl( );
		return urlValue;
	}
	/**
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @generated