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/*
* nearest.c - returns the nearest neighbor to a given
* x,y position
*/
#include <math.h>
#include "global.h"
void p_nearest(struct cache *ibuffer, /* input buffer */
void *obufptr, /* ptr in output buffer */
int cell_type, /* raster map type of obufptr */
double *row_idx, /* row index in input matrix */
double *col_idx, /* column index in input matrix */
struct Cell_head *cellhd /* cell header of input layer */
)
{
int row, col; /* row/col of nearest neighbor */
DCELL *cellp;
/* cut indices to integer and get nearest cell */
/* the row_idx, col_idx correction for bilinear/bicubic does not apply here
*/
row = (int)floor(*row_idx);
col = (int)floor(*col_idx);
/* check for out of bounds - if out of bounds set NULL value */
if (row < 0 || row >= cellhd->rows || col < 0 || col >= cellhd->cols) {
Rast_set_null_value(obufptr, 1, cell_type);
return;
}
cellp = CPTR(ibuffer, row, col);
if (Rast_is_d_null_value(cellp)) {
Rast_set_null_value(obufptr, 1, cell_type);
return;
}
Rast_set_d_value(obufptr, *cellp, cell_type);
}
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