findFaceHoles()

static void findFaceHoles ( Face **  faces, int  nfaces  )

static

Definition at line 1198 of file liblwgeom/lwgeom_geos.c.

References compare_by_envarea(), Face_t::envarea, Face_t::geom, LWDEBUGF, and Face_t::parent.

Referenced by LWGEOM_GEOS_buildArea().

{
  int i, j, h;

  /* We sort by envelope area so that we know holes are only
   * after their shells */
  qsort(faces, nfaces, sizeof(Face*), compare_by_envarea);
  for (i=0; i<nfaces; ++i) {
    Face* f = faces[i];
    int nholes = GEOSGetNumInteriorRings(f->geom);
    LWDEBUGF(2, "Scanning face %d with env area %g and %d holes", i, f->envarea, nholes);
    for (h=0; h<nholes; ++h) {
      const GEOSGeometry *hole = GEOSGetInteriorRingN(f->geom, h);
      LWDEBUGF(2, "Looking for hole %d/%d of face %d among %d other faces", h+1, nholes, i, nfaces-i-1);
      for (j=i+1; j<nfaces; ++j) {
                const GEOSGeometry *f2er;
        Face* f2 = faces[j];
        if ( f2->parent ) continue; /* hole already assigned */
        f2er = GEOSGetExteriorRing(f2->geom);
        /* TODO: can be optimized as the ring would have the
         *       same vertices, possibly in different order.
         *       maybe comparing number of points could already be
         *       useful.
         */
        if ( GEOSEquals(f2er, hole) ) {
          LWDEBUGF(2, "Hole %d/%d of face %d is face %d", h+1, nholes, i, j);
          f2->parent = f;
          break;
        }
      }
    }
  }
}

Here is the call graph for this function:

Here is the caller graph for this function: