Octave has a provision for attaching application-defined data to a graphics handle. The data can be anything which is meaningful to the application, and will be completely ignored by Octave.
Set the named application data to value for the object(s) with handle(s) h. If the application data with the specified name does not exist, it is created.
Return a structure, appdata, whose fields correspond to the appdata properties.
Delete the named application data for the object(s) with handle(s) h.