PostGIS  2.5.0rc1dev-r@@SVN_REVISION@@

◆ lwline_get_lwpoint()

LWPOINT* lwline_get_lwpoint ( const LWLINE line,
uint32_t  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 318 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 _lwt_AddLineEdge(), gserialized_distance_nd(), lwcompound_get_endpoint(), lwcompound_get_lwpoint(), lwgeom_collect_endpoints(), LWGEOM_dumppoints(), LWGEOM_endpoint_linestring(), LWGEOM_pointn_linestring(), LWGEOM_startpoint_linestring(), and lwline_covers_lwline().

319 {
320  POINT4D pt;
321  LWPOINT *lwpoint;
322  POINTARRAY *pa;
323 
324  if ( lwline_is_empty(line) || where >= line->points->npoints )
325  return NULL;
326 
328  pt = getPoint4d(line->points, where);
329  ptarray_append_point(pa, &pt, LW_TRUE);
330  lwpoint = lwpoint_construct(line->srid, NULL, pa);
331  return lwpoint;
332 }
POINTARRAY * ptarray_construct_empty(char hasz, char hasm, uint32_t maxpoints)
Create a new POINTARRAY with no points.
Definition: ptarray.c:70
int lwline_is_empty(const LWLINE *line)
Definition: lwline.c:511
int32_t srid
Definition: liblwgeom.h:423
POINT4D getPoint4d(const POINTARRAY *pa, uint32_t n)
Definition: lwgeom_api.c:96
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_FALSE, then a duplicate point will not be added.
Definition: ptarray.c:156
#define LW_TRUE
Return types for functions with status returns.
Definition: liblwgeom.h:75
#define FLAGS_GET_Z(flags)
Macros for manipulating the 'flags' byte.
Definition: liblwgeom.h:139
#define FLAGS_GET_M(flags)
Definition: liblwgeom.h:140
LWPOINT * lwpoint_construct(int srid, GBOX *bbox, POINTARRAY *point)
Definition: lwpoint.c:129
uint8_t flags
Definition: liblwgeom.h:421
POINTARRAY * points
Definition: liblwgeom.h:424
uint32_t npoints
Definition: liblwgeom.h:373
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