Method InsertLocalMinimaIntoAEL

renderers/agg/src/clipper.cpp:1049–1123

//------------------------------------------------------------------------------

void Clipper::InsertLocalMinimaIntoAEL( const long64 botY)
{
  while(  m_CurrentLM  && ( m_CurrentLM->Y == botY ) )
  {
    TEdge* lb = m_CurrentLM->leftBound;
    TEdge* rb = m_CurrentLM->rightBound;

    InsertEdgeIntoAEL( lb );
    InsertScanbeam( lb->ytop );
    InsertEdgeIntoAEL( rb );

    if ( IsNonZeroFillType( *lb) )
      rb->windDelta = -lb->windDelta;
    else
    {
      lb->windDelta = 1;
      rb->windDelta = 1;
    }
    SetWindingCount( *lb );
    rb->windCnt = lb->windCnt;
    rb->windCnt2 = lb->windCnt2;

    if(  rb->dx == horizontal )
    {
      //nb: only rightbounds can have a horizontal bottom edge
      AddEdgeToSEL( rb );
      InsertScanbeam( rb->nextInLML->ytop );
    }
    else
      InsertScanbeam( rb->ytop );

    if( IsContributing(*lb) )
      AddLocalMinPoly( lb, rb, IntPoint(lb->xcurr, m_CurrentLM->Y) );

    //if output polygons share an edge, they'll need joining later ...
    if (lb->outIdx >= 0 && lb->prevInAEL &&
      lb->prevInAEL->outIdx >= 0 && lb->prevInAEL->xcurr == lb->xbot &&
       SlopesEqual(*lb, *lb->prevInAEL))
         AddJoin(lb, lb->prevInAEL);

    //if any output polygons share an edge, they'll need joining later ...
    if (rb->outIdx >= 0)
    {
      if (rb->dx == horizontal)
      {
        for (HorzJoinList::size_type i = 0; i < m_HorizJoins.size(); ++i)
        {
          IntPoint pt, pt2; //returned by GetOverlapSegment() but unused here.
          HorzJoinRec* hj = m_HorizJoins[i];
          //if horizontals rb and hj.edge overlap, flag for joining later ...
          if (GetOverlapSegment(IntPoint(hj->edge->xbot, hj->edge->ybot),
            IntPoint(hj->edge->xtop, hj->edge->ytop),
            IntPoint(rb->xbot, rb->ybot),
            IntPoint(rb->xtop, rb->ytop), pt, pt2))
              AddJoin(hj->edge, rb, hj->savedIdx);
        }
      }
    }