ObjectARX自定義實體的最近點和垂點捕捉演算法

case AcDb::kOsModeNear:

       {

           AcGeLine3d line3d(m_ptA,m_ptC);         

           AcGePointOnCurve3d tmpPt;

           line3d.getClosestPointTo(pickPoint,tmpPt);

           AcGePoint3d pt=tmpPt.point();

           snapPoints.append(AcGePoint3d(pt));

           line3d.set(m_ptB,m_ptD);

           line3d.getClosestPointTo(pickPoint,tmpPt);

           pt=tmpPt.point();

           snapPoints.append(AcGePoint3d(pt));

       }

       break;

    case AcDb::kOsModePerp:

       {

           AcGeLine3d line3d(m_ptA,m_ptC);         

           AcGePointOnCurve3d tmpPt;

           line3d.getClosestPointTo(lastPoint,tmpPt);

           AcGePoint3d pt=tmpPt.point();

           snapPoints.append(AcGePoint3d(pt));

           line3d.set(m_ptB,m_ptD);

           line3d.getClosestPointTo(lastPoint,tmpPt);

           pt=tmpPt.point();

           snapPoints.append(AcGePoint3d(pt));

       }

       break;