[GRASS-SVN] r41911 - in grass/branches/develbranch_6/doc: . python

[svn_grass at osgeo.org]

Author: neteler
Date: 2010-04-17 08:08:29 -0400 (Sat, 17 Apr 2010)
New Revision: 41911

Added:
   grass/branches/develbranch_6/doc/python/
   grass/branches/develbranch_6/doc/python/example_ctypes.py
Log:
glynn: ctypes Python example; with small additions

Added: grass/branches/develbranch_6/doc/python/example_ctypes.py
===================================================================
--- grass/branches/develbranch_6/doc/python/example_ctypes.py	                        (rev 0)
+++ grass/branches/develbranch_6/doc/python/example_ctypes.py	2010-04-17 12:08:29 UTC (rev 41911)
@@ -0,0 +1,49 @@
+#!/usr/bin/env python
+import os, sys, subprocess
+from ctypes import *
+grass = CDLL("libgrass_gis.so")
+
+if not os.environ.has_key("GISBASE"):
+    print "You must be in GRASS GIS to run this program."
+    sys.exit(1)
+
+if len(sys.argv)==2:
+  input = sys.argv[1]
+else:
+  input = raw_input("Raster Map Name? ")
+
+# initialize
+s = subprocess.Popen(['g.version','-r'], stdout=subprocess.PIPE).communicate()[0]
+for line in s.splitlines():
+    if line.startswith('Revision:'):
+        version = '$' + line + '$'
+grass.G__gisinit(version, '')
+ 
+# find map in search path
+mapset = grass.G_find_cell2(input, '')
+mapset = c_char_p(mapset).value
+ 
+# determine the inputmap type (CELL/FCELL/DCELL) */
+data_type = grass.G_raster_map_type(input, mapset)
+
+if data_type == 0:
+    ptype = POINTER(c_int)
+elif data_type == 1:
+    ptype = POINTER(c_float)
+elif data_type == 2:
+    ptype = POINTER(c_double)
+ 
+infd = grass.G_open_cell_old(input, mapset)
+inrast = grass.G_allocate_raster_buf(data_type)
+inrast = cast(c_void_p(inrast), ptype)
+
+rows = grass.G_window_rows()
+cols = grass.G_window_cols()
+ 
+for rown in xrange(rows):
+    grass.G_get_raster_row(infd, inrast, rown, data_type)
+    print rown, inrast[0:cols]
+ 
+grass.G_close_cell(infd)
+grass.G_free(inrast)
+