GRASS GIS 7 Programmer's Manual  7.7.svn(2018)-r73675
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get_window.c
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1 /*!
2  \file lib/gis/get_window.c
3 
4  \brief GIS Library - Get window (i.e. GRASS region)
5 
6  (C) 2001-2009, 2011 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 Original author CERL
12 */
13 
14 #include <stdlib.h>
15 
16 #include <grass/gis.h>
17 #include <grass/glocale.h>
18 
19 #include "G.h"
20 #include "gis_local_proto.h"
21 
22 static struct state {
23  int initialized;
24  struct Cell_head dbwindow;
25 } state;
26 
27 static struct state *st = &state;
28 
29 /*!
30  \brief Get the current region
31 
32  Reads the region as stored in the WIND file in the user's current
33  mapset into region.
34 
35  3D values are set to defaults if not available in WIND file. An
36  error message is printed and exit() is called if there is a problem
37  reading the region.
38 
39  <b>Note:</b> GRASS applications that read or write raster maps
40  should not use this routine since its use implies that the active
41  module region will not be used. Programs that read or write raster
42  map data (or vector data) can query the active module region using
43  Rast_window_rows() and Rast_window_cols().
44 
45  \param[out] window pointer to Cell_head
46 */
47 void G_get_window(struct Cell_head *window)
48 {
49  const char *regvar;
50 
51  if (G_is_initialized(&st->initialized)) {
52  *window = st->dbwindow;
53  return;
54  }
55 
56  /* Optionally read the region from environment variable */
57  regvar = getenv("GRASS_REGION");
58 
59  if (regvar) {
60  char **tokens = G_tokenize(regvar, ";");
61  G__read_Cell_head_array(tokens, &st->dbwindow, 0);
62  G_free_tokens(tokens);
63  }
64  else {
65  char *wind = getenv("WIND_OVERRIDE");
66  if (wind)
67  G_get_element_window(&st->dbwindow, "windows", wind, G_mapset());
68  else
69  G_get_element_window(&st->dbwindow, "", "WIND", G_mapset());
70  }
71 
72  *window = st->dbwindow;
73 
74  if (!G__.window_set) {
75  G__.window_set = 1;
76  G__.window = st->dbwindow;
77  }
78 
79  G_initialize_done(&st->initialized);
80 }
81 
82 /*!
83  \brief Get the default region
84 
85  Reads the default region for the location into <i>region.</i> 3D
86  values are set to defaults if not available in WIND file.
87 
88  An error message is printed and exit() is called if there is a
89  problem reading the default region.
90 
91  \param[out] window pointer to Cell_head
92 */
93 void G_get_default_window(struct Cell_head *window)
94 {
95  G_get_element_window(window, "", "DEFAULT_WIND", "PERMANENT");
96 }
97 
98 /*!
99  \brief Get region for selected element (raster, vector, window, etc.)
100 
101  G_fatal_error() is called on error
102 
103  \param[out] window pointer to Cell_head
104  \param element element type
105  \param name element name
106  \param mapset mapset name
107 */
108 void G_get_element_window(struct Cell_head *window,
109  const char *element, const char *name, const char *mapset)
110 {
111  FILE *fp;
112 
113  G_zero(window, sizeof(struct Cell_head));
114 
115  /* Read from file */
116  fp = G_fopen_old(element, name, mapset);
117  if (!fp)
118  G_fatal_error(_("Unable to open element file <%s> for <%s@%s>"),
119  element, name, mapset);
120 
121  G_fseek(fp, 0, SEEK_END);
122  if (!G_ftell(fp))
123  G_fatal_error(_("Region file %s/%s/%s is empty"), mapset, element, name);
124  G_fseek(fp, 0, SEEK_SET);
125  G__read_Cell_head(fp, window, 0);
126  fclose(fp);
127 }
128 
129 /*!
130  \brief Unset current region
131 */
133 {
134  st->initialized = 0;
135  G__.window_set = 0;
136 }
void G_get_window(struct Cell_head *window)
Get the current region.
Definition: get_window.c:47
2D/3D raster map header (used also for region)
Definition: gis.h:390
off_t G_ftell(FILE *fp)
Get the current file position of the stream.
Definition: gis/seek.c:29
char ** G_tokenize(const char *buf, const char *delim)
Tokenize string.
Definition: gis/token.c:48
void G__read_Cell_head(FILE *fd, struct Cell_head *cellhd, int is_cellhd)
Read cell header (for internal use only)
Definition: rd_cellhd.c:57
int G_is_initialized(int *p)
Definition: counter.c:59
void G_initialize_done(int *p)
Definition: counter.c:76
void G_unset_window()
Unset current region.
Definition: get_window.c:132
void G_fatal_error(const char *msg,...)
Print a fatal error message to stderr.
Definition: gis/error.c:160
Definition: lidar.h:89
struct Cell_head window
Definition: G.h:6
Definition: G.h:4
struct state * st
Definition: parser.c:102
void G__read_Cell_head_array(char **array, struct Cell_head *cellhd, int is_cellhd)
Read window from NULL terminated array of strings (for internal use only)
Definition: rd_cellhd.c:97
fclose(fd)
int window_set
Definition: G.h:7
void G_get_default_window(struct Cell_head *window)
Get the default region.
Definition: get_window.c:93
void G_fseek(FILE *fp, off_t offset, int whence)
Change the file position of the stream.
Definition: gis/seek.c:50
void G_free_tokens(char **tokens)
Free memory allocated to tokens.
Definition: gis/token.c:204
#define _(str)
Definition: glocale.h:13
void G_get_element_window(struct Cell_head *window, const char *element, const char *name, const char *mapset)
Get region for selected element (raster, vector, window, etc.)
Definition: get_window.c:108
const char * G_mapset(void)
Get current mapset name.
Definition: gis/mapset.c:33
void G_zero(void *buf, int i)
Zero out a buffer, buf, of length i.
Definition: gis/zero.c:23
FILE * G_fopen_old(const char *element, const char *name, const char *mapset)
Open a database file for reading.
Definition: gis/open.c:253
const char * name
Definition: named_colr.c:7
char * getenv()
struct state state
Definition: parser.c:101