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
* @return the meta object for the attribute '<em>Multiplier</em>'.
	 * @see org.eclipse.birt.chart.model.attribute.JavaNumberFormatSpecifier#getMultiplier()
	 * @see #getJavaNumberFormatSpecifier()
	 * @generated
	 */
	EAttribute getJavaNumberFormatSpecifier_Multiplier( );
	/**
	 * Returns the meta object for class '{@link org.eclipse.birt.chart.model.attribute.LineAttributes <em>Line Attributes</em>}'.
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @return the meta object for class '<em>Line Attributes</em>'.
	 * @see org.eclipse.birt.chart.model.attribute.LineAttributes
	 * @generated
	 */
	EClass getLineAttributes( );
	/**
	 * Returns the meta object for the attribute '{@link org.eclipse.birt.chart.model.attribute.LineAttributes#getStyle <em>Style</em>}'.
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @return the meta object for the attribute '<em>Style</em>'.
	 * @see org.eclipse.birt.chart.model.attribute.LineAttributes#getStyle()
	 * @see #getLineAttributes()
	 * @generated
	 */
	EAttribute getLineAttributes_Style( );
	/**
	 * Returns the meta object for the attribute '{@link org.eclipse.birt.chart.model.attribute.LineAttributes#getThickness <em>Thickness</em>}'.
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @return the meta object for the attribute '<em>Thickness</em>'.
	 * @see org.eclipse.birt.chart.model.attribute.LineAttributes#getThickness()
	 * @see #getLineAttributes()
	 * @generated