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/AttributeFactory.java
Interactivity createInteractivity( );
	/**
	 * Returns a new object of class '<em>Java Date Format Specifier</em>'.
	 * <!-- begin-user-doc --> <!--
	 * end-user-doc -->
	 * @return a new object of class '<em>Java Date Format Specifier</em>'.
	 * @generated
	 */
	JavaDateFormatSpecifier createJavaDateFormatSpecifier( );
	/**
	 * Returns a new object of class '<em>Java Number Format Specifier</em>'.
	 * <!-- begin-user-doc --> <!--
	 * end-user-doc -->
	 * @return a new object of class '<em>Java Number Format Specifier</em>'.
	 * @generated
	 */
	JavaNumberFormatSpecifier createJavaNumberFormatSpecifier( );
	/**
	 * Returns a new object of class '<em>Line Attributes</em>'.
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @return a new object of class '<em>Line Attributes</em>'.
	 * @generated
	 */
	LineAttributes createLineAttributes( );
	/**
	 * Returns a new object of class '<em>Location</em>'.
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @return a new object of class '<em>Location</em>'.
	 * @generated
	 */