PostGIS  2.5.0dev-r@@SVN_REVISION@@
int rt_band_get_pixel_of_value ( rt_band  band,
int  exclude_nodata_value,
double *  searchset,
int  searchcount,
rt_pixel pixels 
)

Search band for pixel(s) with search values.

Parameters
band: the band to query for minimum and maximum pixel values
exclude_nodata_value: if non-zero, ignore nodata values
searchset: array of values to count
searchcount: the number of search values
pixels: pixels with the search value
Returns
-1 on error, otherwise number of pixels

Definition at line 1519 of file rt_band.c.

References genraster::count, ES_NONE, FALSE, FLT_NEQ, rt_band_t::hasnodata, rt_band_t::height, rt_band_t::isnodata, rt_pixel_t::nodata, pixval::pixel, rt_band_t::pixtype, pixval::pixval, RASTER_DEBUG, rt_band_get_pixel(), rt_pixtype_compare_clamped_values(), rtalloc(), rterror(), rtrealloc(), rt_pixel_t::value, rt_band_t::width, pixval::x, rt_pixel_t::x, pixval::y, and rt_pixel_t::y.

Referenced by RASTER_pixelOfValue(), and test_band_get_pixel_of_value().

1523  {
1524  int x;
1525  int y;
1526  int i;
1527  double pixval;
1528  int err;
1529  int count = 0;
1530  int isnodata = 0;
1531  int isequal = 0;
1532 
1533  rt_pixel pixel = NULL;
1534 
1535  assert(NULL != band);
1536  assert(NULL != pixels);
1537  assert(NULL != searchset && searchcount > 0);
1538 
1539  if (!band->hasnodata)
1540  exclude_nodata_value = FALSE;
1541  /* band is NODATA and exclude_nodata_value = TRUE, nothing to search */
1542  else if (exclude_nodata_value && band->isnodata) {
1543  RASTER_DEBUG(4, "Pixels cannot be searched as band is NODATA and excluding NODATA values");
1544  return 0;
1545  }
1546 
1547  for (x = 0; x < band->width; x++) {
1548  for (y = 0; y < band->height; y++) {
1549  err = rt_band_get_pixel(band, x, y, &pixval, &isnodata);
1550  if (err != ES_NONE) {
1551  rterror("rt_band_get_pixel_of_value: Cannot get band pixel");
1552  return -1;
1553  }
1554  else if (exclude_nodata_value && isnodata)
1555  continue;
1556 
1557  for (i = 0; i < searchcount; i++) {
1558  if (rt_pixtype_compare_clamped_values(band->pixtype, searchset[i], pixval, &isequal) != ES_NONE) {
1559  continue;
1560  }
1561 
1562  if (FLT_NEQ(pixval, searchset[i]) || !isequal)
1563  continue;
1564 
1565  /* match found */
1566  count++;
1567  if (*pixels == NULL)
1568  *pixels = (rt_pixel) rtalloc(sizeof(struct rt_pixel_t) * count);
1569  else
1570  *pixels = (rt_pixel) rtrealloc(*pixels, sizeof(struct rt_pixel_t) * count);
1571  if (*pixels == NULL) {
1572  rterror("rt_band_get_pixel_of_value: Could not allocate memory for pixel(s)");
1573  return -1;
1574  }
1575 
1576  pixel = &((*pixels)[count - 1]);
1577  pixel->x = x;
1578  pixel->y = y;
1579  pixel->nodata = 0;
1580  pixel->value = pixval;
1581  }
1582  }
1583  }
1584 
1585  return count;
1586 }
struct rt_pixel_t * rt_pixel
Definition: librtcore.h:147
rt_pixtype pixtype
Definition: librtcore.h:2265
void rterror(const char *fmt,...)
Wrappers used for reporting errors and info.
Definition: rt_context.c:199
void * rtalloc(size_t size)
Wrappers used for managing memory.
Definition: rt_context.c:171
void * rtrealloc(void *mem, size_t size)
Definition: rt_context.c:179
uint16_t height
Definition: librtcore.h:2268
double value
Definition: librtcore.h:2289
tuple pixval
Definition: pixval.py:93
#define FLT_NEQ(x, y)
Definition: librtcore.h:2184
int count
Definition: genraster.py:56
rt_errorstate rt_band_get_pixel(rt_band band, int x, int y, double *value, int *nodata)
Get pixel value.
Definition: rt_band.c:1088
uint8_t nodata
Definition: librtcore.h:2288
uint16_t width
Definition: librtcore.h:2267
tuple x
Definition: pixval.py:53
int32_t isnodata
Definition: librtcore.h:2270
#define FALSE
Definition: dbfopen.c:168
#define RASTER_DEBUG(level, msg)
Definition: librtcore.h:295
int32_t hasnodata
Definition: librtcore.h:2269
tuple pixel
Definition: pixval.py:90
tuple y
Definition: pixval.py:54
rt_errorstate rt_pixtype_compare_clamped_values(rt_pixtype pixtype, double val, double refval, int *isequal)
Test to see if two values are equal when clamped.
Definition: rt_pixel.c:200

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