How to obtain the hatch entity from the hatched entity?

By Gopinath Taget

You might wonder, when an entity is hatched, is there is an associative entity created that is the hatch (an AcDbHatch)? And how do I locate this object?

The way the hatch responds to changes in the entity is through notification. The hatch is actually made a persistent reactor of the entity in the hatch. You can then obtain the hatch entity in this way. The following code sample demonstrates this:

void getHatchEntity()    {     ads_name eName;     ads_point pt;          if( RTNORM != acedEntSel(_T("nSelect the entity"), eName, pt ) )      return;     AcDbObjectId id;     acdbGetObjectId( id, eName );          AcDbEntity* pEnt;     acdbOpenObject(pEnt, id, AcDb::kForRead );     if( pEnt == NULL )       return;          AcDbHatch* pHatch = NULL;     AcDbVoidPtrArray* pReactors = pEnt->reactors();     for( int i=0; pHatch == NULL &&       ilength(); i++ ) {      if( acdbIsPersistentReactor( pReactors->at(i) )) {       AcDbObjectId id =         acdbPersistentReactorObjectId( pReactors->at(i));       acdbOpenObject(pHatch, id, AcDb::kForRead );      }     }     if( pHatch != NULL ) {      pHatch->highlight();      pHatch->close();     }     pEnt->close();    }