PostGIS  2.5.7dev-r@@SVN_REVISION@@

◆ lwgeom_difference()

LWGEOM* lwgeom_difference ( const LWGEOM geom1,
const LWGEOM geom2 
)

Definition at line 756 of file liblwgeom/lwgeom_geos.c.

757 {
758  LWGEOM* result;
759  int32_t srid = RESULT_SRID(geom1, geom2);
760  uint8_t is3d = (FLAGS_GET_Z(geom1->flags) || FLAGS_GET_Z(geom2->flags));
761  GEOSGeometry *g1, *g2, *g3;
762 
763  if (srid == SRID_INVALID) return NULL;
764 
765  /* A.Intersection(Empty) == Empty */
766  if (lwgeom_is_empty(geom2)) return lwgeom_clone_deep(geom1); /* match empty type? */
767 
768  /* Empty.Intersection(A) == Empty */
769  if (lwgeom_is_empty(geom1)) return lwgeom_clone_deep(geom1); /* match empty type? */
770 
771  initGEOS(lwnotice, lwgeom_geos_error);
772 
773  if (!(g1 = LWGEOM2GEOS(geom1, AUTOFIX))) GEOS_FAIL();
774  if (!(g2 = LWGEOM2GEOS(geom2, AUTOFIX))) GEOS_FREE_AND_FAIL(g1);
775 
776  g3 = GEOSDifference(g1, g2);
777 
778  if (!g3) GEOS_FREE_AND_FAIL(g1, g2);
779  GEOSSetSRID(g3, srid);
780 
781  if (!(result = GEOS2LWGEOM(g3, is3d)))
782  GEOS_FREE_AND_FAIL(g1, g2, g3);
783 
784  GEOS_FREE(g1, g2, g3);
785  return result;
786 }
#define GEOS_FREE(...)
#define AUTOFIX
#define RESULT_SRID(...)
#define GEOS_FAIL()
#define GEOS_FREE_AND_FAIL(...)
GEOSGeometry * LWGEOM2GEOS(const LWGEOM *lwgeom, uint8_t autofix)
LWGEOM * GEOS2LWGEOM(const GEOSGeometry *geom, uint8_t want3d)
void lwgeom_geos_error(const char *fmt,...)
#define SRID_INVALID
Definition: liblwgeom.h:192
LWGEOM * lwgeom_clone_deep(const LWGEOM *lwgeom)
Deep clone an LWGEOM, everything is copied.
Definition: lwgeom.c:520
#define FLAGS_GET_Z(flags)
Macros for manipulating the 'flags' byte.
Definition: liblwgeom.h:140
int lwgeom_is_empty(const LWGEOM *geom)
Return true or false depending on whether a geometry is an "empty" geometry (no vertices members)
Definition: lwgeom.c:1393
void lwnotice(const char *fmt,...)
Write a notice out to the notice handler.
Definition: lwutil.c:177
uint8_t flags
Definition: liblwgeom.h:400
unsigned char uint8_t
Definition: uthash.h:79

References AUTOFIX, LWGEOM::flags, FLAGS_GET_Z, GEOS2LWGEOM(), GEOS_FAIL, GEOS_FREE, GEOS_FREE_AND_FAIL, LWGEOM2GEOS(), lwgeom_clone_deep(), lwgeom_geos_error(), lwgeom_is_empty(), lwnotice(), RESULT_SRID, and SRID_INVALID.

Referenced by _lwt_AddLine(), and geos_difference().

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