使用ObjectARX从三个点创建AcDbArc

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[code]void test2()

{  

  // get the points

  AcGePoint3d p1, p2, p3;  

  if(RTNORM != acedGetPoint(NULL, L"First point: ", asDblArray(p1))  

|| RTNORM != acedGetPoint(NULL, L"Second point: ", asDblArray(p2))  

  || RTNORM != acedGetPoint(NULL, L"Third point: ", asDblArray(p3)))  

  {

    acutPrintf(L"\nFunction canceled\n" );     

    return;   

  }   



  // create an AcGeCirc

  AcGeCircArc3d geArc(p1, p2, p3);

  AcDbArc *pArc = NULL;

  // now convert the AcGeCirc to an AcDbArc

  AcDbCurve::createFromAcGeCurve(geArc, (AcDbCurve*&) pArc);

  // now cast to a smart pointer so we don't have to worry about

  // closing or freeing

  AcDbObjectPointer<AcDbArc> arc;

  arc.acquire(pArc);

  // get the current database

  AcDbDatabase *db = curDoc()->database();

  AcDbBlockTableRecordPointer curSpace(db->currentSpaceId(), AcDb::kForWrite);

  if(curSpace.openStatus() == Acad::eOk)

    curSpace->appendAcDbEntity(arc.object());

}[/code]