_lwt_EdgeRingIterator_next()

static int _lwt_EdgeRingIterator_next ( LWT_EDGERING_POINT_ITERATOR *  it, POINT2D *  pt  )

static

Definition at line 6204 of file lwgeom_topo.c.

{
  LWT_EDGERING_ELEM *el = it->curelem;
  POINTARRAY *pa;
 
  if ( ! el ) return 0; /* finished */
 
  pa = el->edge->geom->points;
 
  int tonext = 0;
  LWDEBUGF(3, "iterator fetching idx %d from pa of %d points", it->curidx, pa->npoints);
  getPoint2d_p(pa, it->curidx, pt);
  if ( el->left ) {
    it->curidx++;
    if ( it->curidx >= (int) pa->npoints ) tonext = 1;
  } else {
    it->curidx--;
    if ( it->curidx < 0 ) tonext = 1;
  }
 
  if ( tonext )
  {
    LWDEBUG(3, "iterator moving to next element");
    it->curelemidx++;
    if ( it->curelemidx < it->ring->size )
    {
      el = it->curelem = it->ring->elems[it->curelemidx];
      it->curidx = el->left ? 0 : el->edge->geom->points->npoints - 1;
    }
    else
    {
      it->curelem = NULL;
    }
  }
 
  return 1;
}

References LWT_EDGERING_POINT_ITERATOR_T::curelem, LWT_EDGERING_POINT_ITERATOR_T::curelemidx, LWT_EDGERING_POINT_ITERATOR_T::curidx, LWT_EDGERING_ELEM_T::edge, LWT_EDGERING_T::elems, LWT_ISO_EDGE::geom, getPoint2d_p(), LWT_EDGERING_ELEM_T::left, LWDEBUG, LWDEBUGF, POINTARRAY::npoints, LWLINE::points, LWT_EDGERING_POINT_ITERATOR_T::ring, and LWT_EDGERING_T::size.

Referenced by _lwt_EdgeRingCrossingCount(), and _lwt_EdgeRingSignedArea().

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