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/AttributePackage.java
/**
	 * Returns the meta object for enum '{@link org.eclipse.birt.chart.model.attribute.DataPointComponentType <em>Data Point Component Type</em>}'.
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @return the meta object for enum '<em>Data Point Component Type</em>'.
	 * @see org.eclipse.birt.chart.model.attribute.DataPointComponentType
	 * @generated
	 */
	EEnum getDataPointComponentType( );
	/**
	 * Returns the meta object for enum '{@link org.eclipse.birt.chart.model.attribute.DataType <em>Data Type</em>}'.
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @return the meta object for enum '<em>Data Type</em>'.
	 * @see org.eclipse.birt.chart.model.attribute.DataType
	 * @generated
	 */
	EEnum getDataType( );
	/**
	 * Returns the meta object for enum '{@link org.eclipse.birt.chart.model.attribute.DateFormatDetail <em>Date Format Detail</em>}'.
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @return the meta object for enum '<em>Date Format Detail</em>'.
	 * @see org.eclipse.birt.chart.model.attribute.DateFormatDetail
	 * @generated
	 */
	EEnum getDateFormatDetail( );
	/**
	 * Returns the meta object for enum '{@link org.eclipse.birt.chart.model.attribute.DateFormatType <em>Date Format Type</em>}'.
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @return the meta object for enum '<em>Date Format Type</em>'.
	 * @see org.eclipse.birt.chart.model.attribute.DateFormatType
	 * @generated