180 lines
6.5 KiB
Python
180 lines
6.5 KiB
Python
|
from ctypes import byref, c_uint
|
||
|
|
|
||
|
|
from django.contrib.gis.geos import prototypes as capi
|
||
|
|
from django.contrib.gis.geos.geometry import GEOSGeometry
|
||
|
|
from django.contrib.gis.geos.libgeos import GEOM_PTR
|
||
|
|
from django.contrib.gis.geos.linestring import LinearRing
|
||
|
|
|
||
|
|
|
||
|
|
class Polygon(GEOSGeometry):
|
||
|
|
_minlength = 1
|
||
|
|
|
||
|
|
def __init__(self, *args, **kwargs):
|
||
|
|
"""
|
||
|
|
Initialize on an exterior ring and a sequence of holes (both
|
||
|
|
instances may be either LinearRing instances, or a tuple/list
|
||
|
|
that may be constructed into a LinearRing).
|
||
|
|
|
||
|
|
Examples of initialization, where shell, hole1, and hole2 are
|
||
|
|
valid LinearRing geometries:
|
||
|
|
>>> from django.contrib.gis.geos import LinearRing, Polygon
|
||
|
|
>>> shell = hole1 = hole2 = LinearRing()
|
||
|
|
>>> poly = Polygon(shell, hole1, hole2)
|
||
|
|
>>> poly = Polygon(shell, (hole1, hole2))
|
||
|
|
|
||
|
|
>>> # Example where a tuple parameters are used:
|
||
|
|
>>> poly = Polygon(((0, 0), (0, 10), (10, 10), (0, 10), (0, 0)),
|
||
|
|
... ((4, 4), (4, 6), (6, 6), (6, 4), (4, 4)))
|
||
|
|
"""
|
||
|
|
if not args:
|
||
|
|
super().__init__(self._create_polygon(0, None), **kwargs)
|
||
|
|
return
|
||
|
|
|
||
|
|
# Getting the ext_ring and init_holes parameters from the argument list
|
||
|
|
ext_ring = args[0]
|
||
|
|
init_holes = args[1:]
|
||
|
|
n_holes = len(init_holes)
|
||
|
|
|
||
|
|
# If initialized as Polygon(shell, (LinearRing, LinearRing)) [for backward-compatibility]
|
||
|
|
if n_holes == 1 and isinstance(init_holes[0], (tuple, list)):
|
||
|
|
if not init_holes[0]:
|
||
|
|
init_holes = ()
|
||
|
|
n_holes = 0
|
||
|
|
elif isinstance(init_holes[0][0], LinearRing):
|
||
|
|
init_holes = init_holes[0]
|
||
|
|
n_holes = len(init_holes)
|
||
|
|
|
||
|
|
polygon = self._create_polygon(n_holes + 1, (ext_ring,) + init_holes)
|
||
|
|
super().__init__(polygon, **kwargs)
|
||
|
|
|
||
|
|
def __iter__(self):
|
||
|
|
"Iterate over each ring in the polygon."
|
||
|
|
for i in range(len(self)):
|
||
|
|
yield self[i]
|
||
|
|
|
||
|
|
def __len__(self):
|
||
|
|
"Return the number of rings in this Polygon."
|
||
|
|
return self.num_interior_rings + 1
|
||
|
|
|
||
|
|
@classmethod
|
||
|
|
def from_bbox(cls, bbox):
|
||
|
|
"Construct a Polygon from a bounding box (4-tuple)."
|
||
|
|
x0, y0, x1, y1 = bbox
|
||
|
|
for z in bbox:
|
||
|
|
if not isinstance(z, (float, int)):
|
||
|
|
return GEOSGeometry('POLYGON((%s %s, %s %s, %s %s, %s %s, %s %s))' %
|
||
|
|
(x0, y0, x0, y1, x1, y1, x1, y0, x0, y0))
|
||
|
|
return Polygon(((x0, y0), (x0, y1), (x1, y1), (x1, y0), (x0, y0)))
|
||
|
|
|
||
|
|
# ### These routines are needed for list-like operation w/ListMixin ###
|
||
|
|
def _create_polygon(self, length, items):
|
||
|
|
# Instantiate LinearRing objects if necessary, but don't clone them yet
|
||
|
|
# _construct_ring will throw a TypeError if a parameter isn't a valid ring
|
||
|
|
# If we cloned the pointers here, we wouldn't be able to clean up
|
||
|
|
# in case of error.
|
||
|
|
if not length:
|
||
|
|
return capi.create_empty_polygon()
|
||
|
|
|
||
|
|
rings = []
|
||
|
|
for r in items:
|
||
|
|
if isinstance(r, GEOM_PTR):
|
||
|
|
rings.append(r)
|
||
|
|
else:
|
||
|
|
rings.append(self._construct_ring(r))
|
||
|
|
|
||
|
|
shell = self._clone(rings.pop(0))
|
||
|
|
|
||
|
|
n_holes = length - 1
|
||
|
|
if n_holes:
|
||
|
|
holes = (GEOM_PTR * n_holes)(*[self._clone(r) for r in rings])
|
||
|
|
holes_param = byref(holes)
|
||
|
|
else:
|
||
|
|
holes_param = None
|
||
|
|
|
||
|
|
return capi.create_polygon(shell, holes_param, c_uint(n_holes))
|
||
|
|
|
||
|
|
def _clone(self, g):
|
||
|
|
if isinstance(g, GEOM_PTR):
|
||
|
|
return capi.geom_clone(g)
|
||
|
|
else:
|
||
|
|
return capi.geom_clone(g.ptr)
|
||
|
|
|
||
|
|
def _construct_ring(self, param, msg=(
|
||
|
|
'Parameter must be a sequence of LinearRings or objects that can initialize to LinearRings')):
|
||
|
|
"Try to construct a ring from the given parameter."
|
||
|
|
if isinstance(param, LinearRing):
|
||
|
|
return param
|
||
|
|
try:
|
||
|
|
ring = LinearRing(param)
|
||
|
|
return ring
|
||
|
|
except TypeError:
|
||
|
|
raise TypeError(msg)
|
||
|
|
|
||
|
|
def _set_list(self, length, items):
|
||
|
|
# Getting the current pointer, replacing with the newly constructed
|
||
|
|
# geometry, and destroying the old geometry.
|
||
|
|
prev_ptr = self.ptr
|
||
|
|
srid = self.srid
|
||
|
|
self.ptr = self._create_polygon(length, items)
|
||
|
|
if srid:
|
||
|
|
self.srid = srid
|
||
|
|
capi.destroy_geom(prev_ptr)
|
||
|
|
|
||
|
|
def _get_single_internal(self, index):
|
||
|
|
"""
|
||
|
|
Return the ring at the specified index. The first index, 0, will
|
||
|
|
always return the exterior ring. Indices > 0 will return the
|
||
|
|
interior ring at the given index (e.g., poly[1] and poly[2] would
|
||
|
|
return the first and second interior ring, respectively).
|
||
|
|
|
||
|
|
CAREFUL: Internal/External are not the same as Interior/Exterior!
|
||
|
|
Return a pointer from the existing geometries for use internally by the
|
||
|
|
object's methods. _get_single_external() returns a clone of the same
|
||
|
|
geometry for use by external code.
|
||
|
|
"""
|
||
|
|
if index == 0:
|
||
|
|
return capi.get_extring(self.ptr)
|
||
|
|
else:
|
||
|
|
# Getting the interior ring, have to subtract 1 from the index.
|
||
|
|
return capi.get_intring(self.ptr, index - 1)
|
||
|
|
|
||
|
|
def _get_single_external(self, index):
|
||
|
|
return GEOSGeometry(capi.geom_clone(self._get_single_internal(index)), srid=self.srid)
|
||
|
|
|
||
|
|
_set_single = GEOSGeometry._set_single_rebuild
|
||
|
|
_assign_extended_slice = GEOSGeometry._assign_extended_slice_rebuild
|
||
|
|
|
||
|
|
# #### Polygon Properties ####
|
||
|
|
@property
|
||
|
|
def num_interior_rings(self):
|
||
|
|
"Return the number of interior rings."
|
||
|
|
# Getting the number of rings
|
||
|
|
return capi.get_nrings(self.ptr)
|
||
|
|
|
||
|
|
def _get_ext_ring(self):
|
||
|
|
"Get the exterior ring of the Polygon."
|
||
|
|
return self[0]
|
||
|
|
|
||
|
|
def _set_ext_ring(self, ring):
|
||
|
|
"Set the exterior ring of the Polygon."
|
||
|
|
self[0] = ring
|
||
|
|
|
||
|
|
# Properties for the exterior ring/shell.
|
||
|
|
exterior_ring = property(_get_ext_ring, _set_ext_ring)
|
||
|
|
shell = exterior_ring
|
||
|
|
|
||
|
|
@property
|
||
|
|
def tuple(self):
|
||
|
|
"Get the tuple for each ring in this Polygon."
|
||
|
|
return tuple(self[i].tuple for i in range(len(self)))
|
||
|
|
coords = tuple
|
||
|
|
|
||
|
|
@property
|
||
|
|
def kml(self):
|
||
|
|
"Return the KML representation of this Polygon."
|
||
|
|
inner_kml = ''.join(
|
||
|
|
"<innerBoundaryIs>%s</innerBoundaryIs>" % self[i + 1].kml
|
||
|
|
for i in range(self.num_interior_rings)
|
||
|
|
)
|
||
|
|
return "<Polygon><outerBoundaryIs>%s</outerBoundaryIs>%s</Polygon>" % (self[0].kml, inner_kml)
|