PostGIS  2.2.8dev-r@@SVN_REVISION@@

◆ lwt_GetFaceGeometry()

LWGEOM* lwt_GetFaceGeometry ( LWT_TOPOLOGY topo,
LWT_ELEMID  face 
)

Return the geometry of a face.

For ST_GetFaceGeometry

Parameters
topothe topology to operate on
faceidentifier of the face
Returns
a polygon geometry representing the face, ownership to caller, to be released with lwgeom_release, or NULL on error (liblwgeom error handler will be invoked with error message)

Definition at line 2828 of file lwgeom_topo.c.

References _lwt_FaceByEdges(), _lwt_release_edges(), LWT_TOPOLOGY_T::be_iface, LWT_TOPOLOGY_T::hasZ, lwerror(), lwfree(), lwpoly_as_lwgeom(), lwpoly_construct_empty(), lwt_be_getEdgeByFace(), lwt_be_getFaceById(), lwt_be_lastErrorMessage(), LWT_COL_EDGE_FACE_LEFT, LWT_COL_EDGE_FACE_RIGHT, LWT_COL_EDGE_GEOM, LWT_COL_FACE_FACE_ID, and LWT_TOPOLOGY_T::srid.

Referenced by lwt_AddPolygon(), and lwt_ChangeEdgeGeom().

2829 {
2830  int numfaceedges;
2831  LWT_ISO_EDGE *edges;
2832  LWT_ISO_FACE *face;
2833  LWPOLY *out;
2834  LWGEOM *outg;
2835  int i;
2836  int fields;
2837 
2838  if ( faceid == 0 )
2839  {
2840  lwerror("SQL/MM Spatial exception - universal face has no geometry");
2841  return NULL;
2842  }
2843 
2844  /* Construct the face geometry */
2845  numfaceedges = 1;
2846  fields = LWT_COL_EDGE_GEOM |
2849  ;
2850  edges = lwt_be_getEdgeByFace( topo, &faceid, &numfaceedges, fields, NULL );
2851  if ( numfaceedges == -1 ) {
2852  lwerror("Backend error: %s", lwt_be_lastErrorMessage(topo->be_iface));
2853  return NULL;
2854  }
2855 
2856  if ( numfaceedges == 0 )
2857  {
2858  i = 1;
2859  face = lwt_be_getFaceById(topo, &faceid, &i, LWT_COL_FACE_FACE_ID);
2860  if ( i == -1 ) {
2861  lwerror("Backend error: %s", lwt_be_lastErrorMessage(topo->be_iface));
2862  return NULL;
2863  }
2864  if ( i == 0 ) {
2865  lwerror("SQL/MM Spatial exception - non-existent face.");
2866  return NULL;
2867  }
2868  lwfree( face );
2869  if ( i > 1 ) {
2870  lwerror("Corrupted topology: multiple face records have face_id=%"
2871  PRId64, faceid);
2872  return NULL;
2873  }
2874  /* Face has no boundary edges, we'll return EMPTY, see
2875  * https://trac.osgeo.org/postgis/ticket/3221 */
2876  out = lwpoly_construct_empty(topo->srid, topo->hasZ, 0);
2877  return lwpoly_as_lwgeom(out);
2878  }
2879 
2880  outg = _lwt_FaceByEdges( topo, edges, numfaceedges );
2881  _lwt_release_edges(edges, numfaceedges);
2882 
2883  return outg;
2884 }
static LWT_ISO_FACE * lwt_be_getFaceById(LWT_TOPOLOGY *topo, const LWT_ELEMID *ids, int *numelems, int fields)
Definition: lwgeom_topo.c:236
#define LWT_COL_EDGE_FACE_LEFT
#define LWT_COL_FACE_FACE_ID
Face fields.
void lwfree(void *mem)
Definition: lwutil.c:214
#define LWT_COL_EDGE_FACE_RIGHT
LWGEOM * lwpoly_as_lwgeom(const LWPOLY *obj)
Definition: lwgeom.c:239
static LWT_ISO_EDGE * lwt_be_getEdgeByFace(LWT_TOPOLOGY *topo, const LWT_ELEMID *ids, int *numelems, int fields, const GBOX *box)
Definition: lwgeom_topo.c:250
static LWGEOM * _lwt_FaceByEdges(LWT_TOPOLOGY *topo, LWT_ISO_EDGE *edges, int numfaceedges)
Definition: lwgeom_topo.c:2781
const LWT_BE_IFACE * be_iface
LWPOLY * lwpoly_construct_empty(int srid, char hasz, char hasm)
Definition: lwpoly.c:66
static void _lwt_release_edges(LWT_ISO_EDGE *edges, int num_edges)
Definition: lwgeom_topo.c:471
#define LWT_COL_EDGE_GEOM
const char * lwt_be_lastErrorMessage(const LWT_BE_IFACE *be)
Definition: lwgeom_topo.c:124
void lwerror(const char *fmt,...)
Write a notice out to the error handler.
Definition: lwutil.c:74
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