| """ |
| This module houses the GEOS ctypes prototype functions for the |
| topological operations on geometries. |
| """ |
| from ctypes import c_char_p, c_double, c_int |
| from django.contrib.gis.geos.libgeos import lgeos, GEOM_PTR |
| from django.contrib.gis.geos.prototypes.errcheck import check_geom, check_string |
| |
| def topology(func, *args): |
| "For GEOS unary topology functions." |
| argtypes = [GEOM_PTR] |
| if args: argtypes += args |
| func.argtypes = argtypes |
| func.restype = GEOM_PTR |
| func.errcheck = check_geom |
| return func |
| |
| ### Topology Routines ### |
| geos_boundary = topology(lgeos.GEOSBoundary) |
| geos_buffer = topology(lgeos.GEOSBuffer, c_double, c_int) |
| geos_centroid = topology(lgeos.GEOSGetCentroid) |
| geos_convexhull = topology(lgeos.GEOSConvexHull) |
| geos_difference = topology(lgeos.GEOSDifference, GEOM_PTR) |
| geos_envelope = topology(lgeos.GEOSEnvelope) |
| geos_intersection = topology(lgeos.GEOSIntersection, GEOM_PTR) |
| geos_pointonsurface = topology(lgeos.GEOSPointOnSurface) |
| geos_preservesimplify = topology(lgeos.GEOSTopologyPreserveSimplify, c_double) |
| geos_simplify = topology(lgeos.GEOSSimplify, c_double) |
| geos_symdifference = topology(lgeos.GEOSSymDifference, GEOM_PTR) |
| geos_union = topology(lgeos.GEOSUnion, GEOM_PTR) |
| |
| # GEOSRelate returns a string, not a geometry. |
| geos_relate = lgeos.GEOSRelate |
| geos_relate.argtypes = [GEOM_PTR, GEOM_PTR] |
| geos_relate.errcheck = check_string |
