PostGIS  2.5.7dev-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 2786 of file lwgeom_topo.c.

2787 {
2788  int numfaceedges;
2789  LWT_ISO_EDGE *edges;
2790  LWT_ISO_FACE *face;
2791  LWPOLY *out;
2792  LWGEOM *outg;
2793  int i;
2794  int fields;
2795 
2796  if ( faceid == 0 )
2797  {
2798  lwerror("SQL/MM Spatial exception - universal face has no geometry");
2799  return NULL;
2800  }
2801 
2802  /* Construct the face geometry */
2803  numfaceedges = 1;
2804  fields = LWT_COL_EDGE_GEOM |
2807  ;
2808  edges = lwt_be_getEdgeByFace( topo, &faceid, &numfaceedges, fields, NULL );
2809  if ( numfaceedges == -1 ) {
2810  lwerror("Backend error: %s", lwt_be_lastErrorMessage(topo->be_iface));
2811  return NULL;
2812  }
2813 
2814  if ( numfaceedges == 0 )
2815  {
2816  i = 1;
2817  face = lwt_be_getFaceById(topo, &faceid, &i, LWT_COL_FACE_FACE_ID);
2818  if ( i == -1 ) {
2819  lwerror("Backend error: %s", lwt_be_lastErrorMessage(topo->be_iface));
2820  return NULL;
2821  }
2822  if ( i == 0 ) {
2823  lwerror("SQL/MM Spatial exception - non-existent face.");
2824  return NULL;
2825  }
2826  lwfree( face );
2827  if ( i > 1 ) {
2828  lwerror("Corrupted topology: multiple face records have face_id=%"
2829  LWTFMT_ELEMID, faceid);
2830  return NULL;
2831  }
2832  /* Face has no boundary edges, we'll return EMPTY, see
2833  * https://trac.osgeo.org/postgis/ticket/3221 */
2834  out = lwpoly_construct_empty(topo->srid, topo->hasZ, 0);
2835  return lwpoly_as_lwgeom(out);
2836  }
2837 
2838  outg = _lwt_FaceByEdges( topo, edges, numfaceedges );
2839  _lwt_release_edges(edges, numfaceedges);
2840 
2841  return outg;
2842 }
LWGEOM * lwpoly_as_lwgeom(const LWPOLY *obj)
Definition: lwgeom.c:320
void lwfree(void *mem)
Definition: lwutil.c:244
LWPOLY * lwpoly_construct_empty(int srid, char hasz, char hasm)
Definition: lwpoly.c:161
#define LWT_COL_EDGE_FACE_RIGHT
#define LWT_COL_FACE_FACE_ID
Face fields.
#define LWT_COL_EDGE_FACE_LEFT
#define LWT_COL_EDGE_GEOM
void lwerror(const char *fmt,...)
Write a notice out to the error handler.
Definition: lwutil.c:190
const char * lwt_be_lastErrorMessage(const LWT_BE_IFACE *be)
Definition: lwgeom_topo.c:120
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:246
static LWT_ISO_FACE * lwt_be_getFaceById(LWT_TOPOLOGY *topo, const LWT_ELEMID *ids, int *numelems, int fields)
Definition: lwgeom_topo.c:232
static LWGEOM * _lwt_FaceByEdges(LWT_TOPOLOGY *topo, LWT_ISO_EDGE *edges, int numfaceedges)
Definition: lwgeom_topo.c:2739
#define LWTFMT_ELEMID
Definition: lwgeom_topo.c:44
static void _lwt_release_edges(LWT_ISO_EDGE *edges, int num_edges)
Definition: lwgeom_topo.c:457
const LWT_BE_IFACE * be_iface

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, LWTFMT_ELEMID, and LWT_TOPOLOGY_T::srid.

Referenced by lwt_AddPolygon(), and lwt_ChangeEdgeGeom().

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