swpagerelsize: add offapi documentation

Change-Id: Ibdc495d604fb6a1c864441b8f7573b90600679c4

offapi/com/sun/star/text/BaseFrameProperties.idl

@@ -336,6 +336,21 @@ published service BaseFrameProperties
         */
         [optional, property] sequence<com::sun::star::beans::PropertyValue> FrameInteropGrabBag;
 
+        /** contains the relation of the relative height of the object.
+            <p> It is only valid if RelativeHeight is greater than zero.</p>
+
+            @see com::sun::star::text::RelOrientation
+            @since LibreOffice 4.3
+         */
+        [optional, property] short RelativeHeightRelation;
+
+        /** contains the relation of the relative width of the object.
+            <p> It is only valid if RelativeWidth is greater than zero.</p>
+
+            @see com::sun::star::text::RelOrientation
+            @since LibreOffice 4.3
+         */
+        [optional, property] short RelativeWidthRelation;
 };