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/*!
* \file lib/raster/window_map.c
*
* \brief Raster Library - Window mapping functions.
*
* (C) 2001-2009 by the GRASS Development Team
*
* This program is free software under the GNU General Public License
* (>=v2). Read the file COPYING that comes with GRASS for details.
*
* \author Original author CERL
*/
#include <stdlib.h>
#include <grass/gis.h>
#include <grass/raster.h>
#include "R.h"
#define alloc_index(n) (COLUMN_MAPPING *)G_malloc((n) * sizeof(COLUMN_MAPPING))
/*!
* \brief Create window mapping.
*
* Creates mapping from cell header into window. The boundaries and
* resolution of the two spaces do not have to be the same or aligned in
* any way.
*
* \param fd file descriptor
*/
void Rast__create_window_mapping(int fd)
{
struct fileinfo *fcb = &R__.fileinfo[fd];
COLUMN_MAPPING *col;
int i;
int x;
double C1, C2;
double west, east;
if (fcb->open_mode >= 0 && fcb->open_mode != OPEN_OLD) /* open for write? */
return;
if (fcb->open_mode == OPEN_OLD) /* already open ? */
G_free(fcb->col_map);
col = fcb->col_map = alloc_index(R__.rd_window.cols);
/*
* for each column in the window, go to center of the cell,
* compute nearest column in the data file
* if column is not in data file, set column to 0
*
* for lat/lon move window so that west is bigger than
* cellhd west.
*/
west = R__.rd_window.west;
east = R__.rd_window.east;
if (R__.rd_window.proj == PROJECTION_LL) {
while (west > fcb->cellhd.west + 360.0) {
west -= 360.0;
east -= 360.0;
}
while (west < fcb->cellhd.west) {
west += 360.0;
east += 360.0;
}
}
C1 = R__.rd_window.ew_res / fcb->cellhd.ew_res;
C2 = (west - fcb->cellhd.west + R__.rd_window.ew_res / 2.0) /
fcb->cellhd.ew_res;
for (i = 0; i < R__.rd_window.cols; i++) {
x = C2;
if (C2 < x) /* adjust for rounding of negatives */
x--;
if (x < 0 || x >= fcb->cellhd.cols) /* not in data file */
x = -1;
*col++ = x + 1;
C2 += C1;
}
/* do wrap around for lat/lon */
if (R__.rd_window.proj == PROJECTION_LL) {
while (east - 360.0 > fcb->cellhd.west) {
east -= 360.0;
west -= 360.0;
col = fcb->col_map;
C2 = (west - fcb->cellhd.west + R__.rd_window.ew_res / 2.0) /
fcb->cellhd.ew_res;
for (i = 0; i < R__.rd_window.cols; i++) {
x = C2;
if (C2 < x) /* adjust for rounding of negatives */
x--;
if (x < 0 || x >= fcb->cellhd.cols) /* not in data file */
x = -1;
if (*col == 0) /* only change those not already set */
*col = x + 1;
col++;
C2 += C1;
}
}
}
G_debug(3, "create window mapping (%d columns)", R__.rd_window.cols);
/* for (i = 0; i < R__.rd_window.cols; i++)
fprintf(stderr, "%s%ld", i % 15 ? " " : "\n", (long)fcb->col_map[i]);
fprintf(stderr, "\n");
*/
/* compute C1,C2 for row window mapping */
fcb->C1 = R__.rd_window.ns_res / fcb->cellhd.ns_res;
fcb->C2 =
(fcb->cellhd.north - R__.rd_window.north + R__.rd_window.ns_res / 2.0) /
fcb->cellhd.ns_res;
}
/*!
* \brief Loops rows until mismatch?.
*
* This routine works fine if the mask is not set. It may give
* incorrect results with a mask, since the mask row may have a
* different repeat value. The issue can be fixed by doing it for the
* mask as well and using the smaller value.
*
* \param fd file descriptor
* \param row starting row
*
* \return number of rows completed
*/
int Rast_row_repeat_nomask(int fd, int row)
{
struct fileinfo *fcb = &R__.fileinfo[fd];
double f;
int r1, r2;
int count;
count = 1;
/* r1 is the row in the raster map itself.
* r2 is the next row(s) in the raster map
* see get_row.c for details on this calculation
*/
f = row * fcb->C1 + fcb->C2;
r1 = f;
if (f < r1)
r1--;
while (++row < R__.rd_window.rows) {
f = row * fcb->C1 + fcb->C2;
r2 = f;
if (f < r2)
r2--;
if (r1 != r2)
break;
count++;
}
return count;
}
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