PostGIS  2.2.7dev-r@@SVN_REVISION@@
static CIRC_NODE* lwpoly_calculate_circ_tree ( const LWPOLY lwpoly)
static

Definition at line 833 of file lwgeodetic_tree.c.

References circ_nodes_merge(), circ_nodes_sort(), circ_tree_new(), circ_node::geom_type, lwalloc(), lwfree(), lwgeom_get_type(), lwpoly_pt_outside(), LWPOLY::nrings, circ_node::pt_outside, and LWPOLY::rings.

Referenced by lwgeom_calculate_circ_tree().

834 {
835  int i = 0, j = 0;
836  CIRC_NODE** nodes;
837  CIRC_NODE* node;
838 
839  /* One ring? Handle it like a line. */
840  if ( lwpoly->nrings == 1 )
841  {
842  node = circ_tree_new(lwpoly->rings[0]);
843  }
844  else
845  {
846  /* Calculate a tree for each non-trivial ring of the polygon */
847  nodes = lwalloc(lwpoly->nrings * sizeof(CIRC_NODE*));
848  for ( i = 0; i < lwpoly->nrings; i++ )
849  {
850  node = circ_tree_new(lwpoly->rings[i]);
851  if ( node )
852  nodes[j++] = node;
853  }
854  /* Put the trees into a spatially correlated order */
855  circ_nodes_sort(nodes, j);
856  /* Merge the trees pairwise up to a parent node and return */
857  node = circ_nodes_merge(nodes, j);
858  /* Don't need the working list any more */
859  lwfree(nodes);
860  }
861 
862  /* Metatdata about polygons, we need this to apply P-i-P tests */
863  /* selectively when doing distance calculations */
864  node->geom_type = lwgeom_get_type((LWGEOM*)lwpoly);
865  lwpoly_pt_outside(lwpoly, &(node->pt_outside));
866 
867  return node;
868 }
Note that p1 and p2 are pointers into an independent POINTARRAY, do not free them.
void lwfree(void *mem)
Definition: lwutil.c:214
uint32_t lwgeom_get_type(const LWGEOM *geom)
Return LWTYPE number.
Definition: lwgeom.c:829
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:441
void lwpoly_pt_outside(const LWPOLY *poly, POINT2D *pt_outside)
Definition: lwgeodetic.c:1423
static CIRC_NODE * circ_nodes_merge(CIRC_NODE **nodes, int num_nodes)
int nrings
Definition: liblwgeom.h:439
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:199

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