# Τεκμηρίωση του Django - 1.10.7

# Πηγαίος κώδικας για το django.contrib.gis.geos.collections

    """
     This module houses the Geometry Collection objects:
     GeometryCollection, MultiPoint, MultiLineString, and MultiPolygon
    """
    import json
    import warnings
    from ctypes import byref, c_int, c_uint

    from django.contrib.gis.geos import prototypes as capi
    from django.contrib.gis.geos.error import GEOSException
    from django.contrib.gis.geos.geometry import GEOSGeometry, LinearGeometryMixin
    from django.contrib.gis.geos.libgeos import geos_version_info, get_pointer_arr
    from django.contrib.gis.geos.linestring import LinearRing, LineString
    from django.contrib.gis.geos.point import Point
    from django.contrib.gis.geos.polygon import Polygon
    from django.utils.deprecation import RemovedInDjango20Warning
    from django.utils.six.moves import range

    class GeometryCollection(GEOSGeometry):
        _typeid = 7

        def __init__(self, *args, **kwargs):
            "Initializes a Geometry Collection from a sequence of Geometry objects."

            # Checking the arguments
            if len(args) == 1:
                # If only one geometry provided or a list of geometries is provided
                #  in the first argument.
                if isinstance(args[0], (tuple, list)):
                    init_geoms = args[0]
                else:
                    init_geoms = args
            else:
                init_geoms = args

            # Ensuring that only the permitted geometries are allowed in this collection
            # this is moved to list mixin super class
            self._check_allowed(init_geoms)

            # Creating the geometry pointer array.
            collection = self._create_collection(len(init_geoms), iter(init_geoms))
            super(GeometryCollection, self).__init__(collection, **kwargs)

        def __iter__(self):
            "Iterates over each Geometry in the Collection."
            for i in range(len(self)):
                yield self[i]

        def __len__(self):
            "Returns the number of geometries in this Collection."
            return self.num_geom

        # ### Methods for compatibility with ListMixin ###
        def _create_collection(self, length, items):
            # Creating the geometry pointer array.
            geoms = get_pointer_arr(length)
            for i, g in enumerate(items):
                # this is a little sloppy, but makes life easier
                # allow GEOSGeometry types (python wrappers) or pointer types
                geoms[i] = capi.geom_clone(getattr(g, 'ptr', g))

            return capi.create_collection(c_int(self._typeid), byref(geoms), c_uint(length))

        def _get_single_internal(self, index):
            return capi.get_geomn(self.ptr, index)

        def _get_single_external(self, index):
            "Returns the Geometry from this Collection at the given index (0-based)."
            # Checking the index and returning the corresponding GEOS geometry.
            return GEOSGeometry(capi.geom_clone(self._get_single_internal(index)), srid=self.srid)

        def _set_list(self, length, items):
            "Create a new collection, and destroy the contents of the previous pointer."
            prev_ptr = self.ptr
            srid = self.srid
            self.ptr = self._create_collection(length, items)
            if srid:
                self.srid = srid
            capi.destroy_geom(prev_ptr)

        _set_single = GEOSGeometry._set_single_rebuild
        _assign_extended_slice = GEOSGeometry._assign_extended_slice_rebuild

        @property
        def json(self):
            if self.__class__.__name__ == 'GeometryCollection':
                return json.dumps({
                    'type': self.__class__.__name__,
                    'geometries': [
                        {'type': geom.__class__.__name__, 'coordinates': geom.coords}
                        for geom in self
                    ],
                })
            return super(GeometryCollection, self).json
        geojson = json

        @property
        def kml(self):
            "Returns the KML for this Geometry Collection."
            return '<MultiGeometry>%s</MultiGeometry>' % ''.join(g.kml for g in self)

        @property
        def tuple(self):
            "Returns a tuple of all the coordinates in this Geometry Collection"
            return tuple(g.tuple for g in self)
        coords = tuple

    # MultiPoint, MultiLineString, and MultiPolygon class definitions.
    class MultiPoint(GeometryCollection):
        _allowed = Point
        _typeid = 4

    class MultiLineString(LinearGeometryMixin, GeometryCollection):
        _allowed = (LineString, LinearRing)
        _typeid = 5

        @property
        def closed(self):
            if geos_version_info()['version'] < '3.5':
                raise GEOSException("MultiLineString.closed requires GEOS >= 3.5.0.")
            return super(MultiLineString, self).closed

    class MultiPolygon(GeometryCollection):
        _allowed = Polygon
        _typeid = 6

        @property
        def cascaded_union(self):
            "Returns a cascaded union of this MultiPolygon."
            warnings.warn(
                "`cascaded_union` is deprecated, use the `unary_union` property instead.",
                RemovedInDjango20Warning, 2
            )
            return GEOSGeometry(capi.geos_cascaded_union(self.ptr), self.srid)

    # Setting the allowed types here since GeometryCollection is defined before
    # its subclasses.
    GeometryCollection._allowed = (Point, LineString, LinearRing, Polygon, MultiPoint, MultiLineString, MultiPolygon)