PostGIS  2.5.1dev-r@@SVN_REVISION@@

◆ ptarray_remove_repeated_points_in_place()

void ptarray_remove_repeated_points_in_place ( POINTARRAY pa,
double  tolerance,
uint32_t  min_points 
)

Definition at line 1453 of file ptarray.c.

References distance2d_sqr_pt_pt(), getPoint2d_cp(), POINTARRAY::npoints, ptarray_copy_point(), and ptarray_point_size().

Referenced by lwgeom_remove_repeated_points_in_place(), and ptarray_remove_repeated_points_minpoints().

1454 {
1455  uint32_t i;
1456  double tolsq = tolerance * tolerance;
1457  const POINT2D *last = NULL;
1458  const POINT2D *pt;
1459  uint32_t n_points = pa->npoints;
1460  uint32_t n_points_out = 1;
1461  size_t pt_size = ptarray_point_size(pa);
1462 
1463  double dsq = FLT_MAX;
1464 
1465  /* No-op on short inputs */
1466  if ( n_points <= min_points ) return;
1467 
1468  last = getPoint2d_cp(pa, 0);
1469  for (i = 1; i < n_points; i++)
1470  {
1471  int last_point = (i == n_points-1);
1472 
1473  /* Look straight into the abyss */
1474  pt = getPoint2d_cp(pa, i);
1475 
1476  /* Don't drop points if we are running short of points */
1477  if (n_points + n_points_out > min_points + i)
1478  {
1479  if (tolerance > 0.0)
1480  {
1481  /* Only drop points that are within our tolerance */
1482  dsq = distance2d_sqr_pt_pt(last, pt);
1483  /* Allow any point but the last one to be dropped */
1484  if (!last_point && dsq <= tolsq)
1485  {
1486  continue;
1487  }
1488  }
1489  else
1490  {
1491  /* At tolerance zero, only skip exact dupes */
1492  if (memcmp((char*)pt, (char*)last, pt_size) == 0)
1493  continue;
1494  }
1495 
1496  /* Got to last point, and it's not very different from */
1497  /* the point that preceded it. We want to keep the last */
1498  /* point, not the second-to-last one, so we pull our write */
1499  /* index back one value */
1500  if (last_point && n_points_out > 1 && tolerance > 0.0 && dsq <= tolsq)
1501  {
1502  n_points_out--;
1503  }
1504  }
1505 
1506  /* Compact all remaining values to front of array */
1507  ptarray_copy_point(pa, i, n_points_out++);
1508  last = pt;
1509  }
1510  /* Adjust array length */
1511  pa->npoints = n_points_out;
1512  return;
1513 }
size_t ptarray_point_size(const POINTARRAY *pa)
Definition: ptarray.c:54
void ptarray_copy_point(POINTARRAY *pa, uint32_t from, uint32_t to)
Definition: lwgeom_api.c:450
unsigned int uint32_t
Definition: uthash.h:78
double distance2d_sqr_pt_pt(const POINT2D *p1, const POINT2D *p2)
Definition: measures.c:2322
const POINT2D * getPoint2d_cp(const POINTARRAY *pa, uint32_t n)
Returns a POINT2D pointer into the POINTARRAY serialized_ptlist, suitable for reading from...
Definition: lwgeom_api.c:364
uint32_t npoints
Definition: liblwgeom.h:373
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