virtual Acad::ErrorStatus getOsnapInfo( AcDbEntity* pickedObject, Adesk::GsMarker gsSelectionMark, const AcGePoint3d& pickPoint, const AcGePoint3d& lastPoint, const AcGeMatrix3d& viewXform, AcArray<AcGePoint3d>& snapPoints, AcArray<int>& geomIdsForPts, AcArray<AcGeCurve3d*>& snapCurves, AcArray<int>& geomIdsForLines) { // Specialised implementation for AcDbPolylines: // Parametrisation of AcDbPolylines is different: each whole numbered paramater appears // at a vertex, so we cannot simply divide by three to get the correct parameter. // Protocol Extension insures that the following assertion is always // true, but check in non-prod versions just to be safe. assert( pickedObject->isKindOf( AcDbPolyline::desc() )); // but in production, a hard cast is fastest AcDbPolyline *pPline = (AcDbPolyline*)pickedObject; Acad::ErrorStatus es; if ( bSnapToSegments ) { // Snap to a third of each of the segments unsigned int numSegs = pPline->numVerts() - 1; AcGeLineSeg3d segLn; AcGeCircArc3d segArc; double startParam, endParam, newParam, dist; AcGePoint3d pt; for ( unsigned int idx = 0; idx < numSegs; idx++ ) { switch( pPline->segType( idx )) { case AcDbPolyline::kLine: es=pPline->getLineSegAt( idx, segLn ); startParam = segLn.paramOf( segLn.startPoint() ); endParam = segLn.paramOf( segLn.endPoint() ); snapPoints.append(segLn.evalPoint( startParam + ((endParam - startParam) / 3 ))); snapPoints.append(segLn.evalPoint( startParam + ((endParam - startParam) * 2 / 3 ))); break; case AcDbPolyline::kArc: es=pPline->getArcSegAt( idx, segArc ); startParam = segArc.paramOf( segArc.startPoint() ); endParam = segArc.paramOf( segArc.endPoint() ); dist = segArc.length( startParam, endParam ); newParam = segArc.paramAtLength( startParam, dist / 3 ); snapPoints.append( segArc.evalPoint( newParam )); newParam = segArc.paramAtLength( startParam, dist * 2 / 3 ); snapPoints.append( segArc.evalPoint( newParam )); break; default: break; } } } else { double endParam; AcGePoint3d pt; double dist; es=pPline->getEndParam( endParam ); es=pPline->getDistAtParam( endParam, dist ); es=pPline->getPointAtDist( dist / 3, pt ); assert(Acad::eOk==es); snapPoints.append( pt ); es=pPline->getPointAtDist( dist * 2 / 3, pt ); assert(Acad::eOk==es); snapPoints.append( pt ); if ( pPline->isClosed() ) { es=pPline->getStartPoint( pt ); snapPoints.append( pt ); } } return Acad::eOk; }