* use this with simple drawings, otherwise call
* {@link HSSFSheet#createDrawingPatriarch()} and
* start from scratch!
*/
public HSSFPatriarch getDrawingPatriarch() {
EscherAggregate agg = getDrawingEscherAggregate();
if(agg == null) return null;
HSSFPatriarch patriarch = new HSSFPatriarch(this, agg);
agg.setPatriarch(patriarch);
// Have it process the records into high level objects
// as best it can do (this step may eat anything
// that isn't supported, you were warned...)
agg.convertRecordsToUserModel();
// Return what we could cope with
return patriarch;
}