| """ |
| This module is for the miscellaneous GEOS routines, particularly the |
| ones that return the area, distance, and length. |
| """ |
| from ctypes import c_int, c_double, POINTER |
| from django.contrib.gis.geos.libgeos import lgeos, GEOM_PTR |
| from django.contrib.gis.geos.prototypes.errcheck import check_dbl |
| |
| ### ctypes generator function ### |
| def dbl_from_geom(func, num_geom=1): |
| """ |
| Argument is a Geometry, return type is double that is passed |
| in by reference as the last argument. |
| """ |
| argtypes = [GEOM_PTR for i in xrange(num_geom)] |
| argtypes += [POINTER(c_double)] |
| func.argtypes = argtypes |
| func.restype = c_int # Status code returned |
| func.errcheck = check_dbl |
| return func |
| |
| ### ctypes prototypes ### |
| |
| # Area, distance, and length prototypes. |
| geos_area = dbl_from_geom(lgeos.GEOSArea) |
| geos_distance = dbl_from_geom(lgeos.GEOSDistance, num_geom=2) |
| geos_length = dbl_from_geom(lgeos.GEOSLength) |
