PostGIS  2.5.2dev-r@@SVN_REVISION@@

## ◆ lwpoly_calculate_circ_tree()

 static CIRC_NODE* lwpoly_calculate_circ_tree ( const LWPOLY * lwpoly )
static

Definition at line 909 of file lwgeodetic_tree.c.

Referenced by lwgeom_calculate_circ_tree().

910 {
911  uint32_t i = 0, j = 0;
912  CIRC_NODE** nodes;
913  CIRC_NODE* node;
914
915  /* One ring? Handle it like a line. */
916  if ( lwpoly->nrings == 1 )
917  {
918  node = circ_tree_new(lwpoly->rings[0]);
919  }
920  else
921  {
922  /* Calculate a tree for each non-trivial ring of the polygon */
923  nodes = lwalloc(lwpoly->nrings * sizeof(CIRC_NODE*));
924  for ( i = 0; i < lwpoly->nrings; i++ )
925  {
926  node = circ_tree_new(lwpoly->rings[i]);
927  if ( node )
928  nodes[j++] = node;
929  }
930  /* Put the trees into a spatially correlated order */
931  circ_nodes_sort(nodes, j);
932  /* Merge the trees pairwise up to a parent node and return */
933  node = circ_nodes_merge(nodes, j);
934  /* Don't need the working list any more */
935  lwfree(nodes);
936  }
937
938  /* Metadata about polygons, we need this to apply P-i-P tests */
939  /* selectively when doing distance calculations */
940  node->geom_type = lwgeom_get_type((LWGEOM*)lwpoly);
941  lwpoly_pt_outside(lwpoly, &(node->pt_outside));
942
943  return node;
944 }
Note that p1 and p2 are pointers into an independent POINTARRAY, do not free them.
uint32_t geom_type
void lwfree(void *mem)
Definition: lwutil.c:244
uint32_t lwgeom_get_type(const LWGEOM *geom)
Return LWTYPE number.
Definition: lwgeom.c:923
uint32_t nrings
Definition: liblwgeom.h:458
unsigned int uint32_t
Definition: uthash.h:78
CIRC_NODE * circ_tree_new(const POINTARRAY *pa)
Build a tree of nodes from a point array, one node per edge.
POINTARRAY ** rings
Definition: liblwgeom.h:460
void lwpoly_pt_outside(const LWPOLY *poly, POINT2D *pt_outside)
Definition: lwgeodetic.c:1453
static CIRC_NODE * circ_nodes_merge(CIRC_NODE **nodes, int num_nodes)
static void circ_nodes_sort(CIRC_NODE **nodes, int num_nodes)
Given a list of nodes, sort them into a spatially consistent order, then pairwise merge them up into ...
POINT2D pt_outside
void * lwalloc(size_t size)
Definition: lwutil.c:229
CIRC_NODE * node
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