PostGIS  2.1.10dev-r@@SVN_REVISION@@
LWPOINT* lwline_get_lwpoint ( LWLINE line,
int  where 
)

Returns freshly allocated LWPOINT that corresponds to the index where.

Returns NULL if the geometry is empty or the index invalid.

Definition at line 294 of file lwline.c.

References LWLINE::flags, FLAGS_GET_M, FLAGS_GET_Z, getPoint4d(), LW_TRUE, lwline_is_empty(), lwpoint_construct(), POINTARRAY::npoints, LWLINE::points, ptarray_append_point(), ptarray_construct_empty(), and LWLINE::srid.

Referenced by lwgeom_collect_endpoints(), LWGEOM_dumppoints(), LWGEOM_endpoint_linestring(), LWGEOM_pointn_linestring(), and LWGEOM_startpoint_linestring().

295 {
296  POINT4D pt;
297  LWPOINT *lwpoint;
298  POINTARRAY *pa;
299 
300  if ( lwline_is_empty(line) || where < 0 || where >= line->points->npoints )
301  return NULL;
302 
304  pt = getPoint4d(line->points, where);
305  ptarray_append_point(pa, &pt, LW_TRUE);
306  lwpoint = lwpoint_construct(line->srid, NULL, pa);
307  return lwpoint;
308 }
int npoints
Definition: liblwgeom.h:327
POINTARRAY * ptarray_construct_empty(char hasz, char hasm, uint32_t maxpoints)
Create a new POINTARRAY with no points.
Definition: ptarray.c:57
int lwline_is_empty(const LWLINE *line)
Definition: lwline.c:464
int32_t srid
Definition: liblwgeom.h:377
POINT4D getPoint4d(const POINTARRAY *pa, int n)
Definition: lwgeom_api.c:202
int ptarray_append_point(POINTARRAY *pa, const POINT4D *pt, int allow_duplicates)
Append a point to the end of an existing POINTARRAY If allow_duplicate is LW_TRUE, then a duplicate point will not be added.
Definition: ptarray.c:141
#define LW_TRUE
Return types for functions with status returns.
Definition: liblwgeom.h:51
#define FLAGS_GET_Z(flags)
Macros for manipulating the 'flags' byte.
Definition: liblwgeom.h:106
#define FLAGS_GET_M(flags)
Definition: liblwgeom.h:107
LWPOINT * lwpoint_construct(int srid, GBOX *bbox, POINTARRAY *point)
Definition: lwpoint.c:96
uint8_t flags
Definition: liblwgeom.h:375
POINTARRAY * points
Definition: liblwgeom.h:378

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