GRASS GIS 8 Programmer's Manual  8.4.0dev(2024)-55b2a2bccc
wind_2_box.c
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1 /*!
2  * \file lib/gis/wind_2_box.c
3  *
4  * \brief GIS Library - Window box functions.
5  *
6  * (C) 2001-2014 by the GRASS Development Team
7  *
8  * This program is free software under the GNU General Public License
9  * (>=v2). Read the file COPYING that comes with GRASS for details.
10  *
11  * \author GRASS GIS Development Team
12  *
13  * \date 1999-2014
14  */
15 
16 #include <grass/gis.h>
17 
18 /**
19  * \brief Adjusts window to a rectangular box.
20  *
21  * Creates a new window <b>dst</b> from a window <b>src</b> which fits
22  * into the rectangular box with dimensions <b>rows</b> by <b>cols</b>.
23  *
24  * \param[in] src source window
25  * \param[in,out] dst destination window
26  * \param[in] rows number of rows in box
27  * \param[in] cols number of columns in box
28  * \return
29  */
30 
31 void G_adjust_window_to_box(const struct Cell_head *src, struct Cell_head *dst,
32  int rows, int cols)
33 {
34  double ew, ns;
35 
36  *dst = *src;
37 
38  /* calculate the effective resolutions */
39  ns = (src->ns_res * src->rows) / rows;
40  ew = (src->ew_res * src->cols) / cols;
41 
42  /* set both resolutions equal to the larger */
43  if (ns > ew)
44  ew = ns;
45  else
46  ns = ew;
47 
48  dst->ns_res = ns;
49  dst->ew_res = ew;
50 
51  /* compute rows and cols */
52  dst->rows = (dst->north - dst->south) / dst->ns_res;
53  dst->cols = (dst->east - dst->west) / dst->ew_res;
54 }
2D/3D raster map header (used also for region)
Definition: gis.h:439
double ew_res
Resolution - east to west cell size for 2D data.
Definition: gis.h:475
double north
Extent coordinates (north)
Definition: gis.h:485
double east
Extent coordinates (east)
Definition: gis.h:489
double ns_res
Resolution - north to south cell size for 2D data.
Definition: gis.h:479
int rows
Number of rows for 2D data.
Definition: gis.h:454
int cols
Number of columns for 2D data.
Definition: gis.h:458
double south
Extent coordinates (south)
Definition: gis.h:487
double west
Extent coordinates (west)
Definition: gis.h:491
void G_adjust_window_to_box(const struct Cell_head *src, struct Cell_head *dst, int rows, int cols)
Adjusts window to a rectangular box.
Definition: wind_2_box.c:31