You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
92 lines
3.6 KiB
92 lines
3.6 KiB
from django.contrib.gis.gdal import OGRException |
|
from django.contrib.gis.geos import GEOSGeometry, GEOSException |
|
from django.forms.widgets import Textarea |
|
from django.template.loader import render_to_string |
|
|
|
class OpenLayersWidget(Textarea): |
|
""" |
|
Renders an OpenLayers map using the WKT of the geometry. |
|
""" |
|
def render(self, name, value, attrs=None): |
|
# Update the template parameters with any attributes passed in. |
|
if attrs: self.params.update(attrs) |
|
|
|
# Defaulting the WKT value to a blank string -- this |
|
# will be tested in the JavaScript and the appropriate |
|
# interfaace will be constructed. |
|
self.params['wkt'] = '' |
|
|
|
# If a string reaches here (via a validation error on another |
|
# field) then just reconstruct the Geometry. |
|
if isinstance(value, basestring): |
|
try: |
|
value = GEOSGeometry(value) |
|
except (GEOSException, ValueError): |
|
value = None |
|
|
|
if value and value.geom_type.upper() != self.geom_type: |
|
value = None |
|
|
|
# Constructing the dictionary of the map options. |
|
self.params['map_options'] = self.map_options() |
|
|
|
# Constructing the JavaScript module name using the ID of |
|
# the GeometryField (passed in via the `attrs` keyword). |
|
self.params['module'] = 'geodjango_%s' % self.params['field_name'] |
|
|
|
if value: |
|
# Transforming the geometry to the projection used on the |
|
# OpenLayers map. |
|
srid = self.params['srid'] |
|
if value.srid != srid: |
|
try: |
|
value.transform(srid) |
|
wkt = value.wkt |
|
except OGRException: |
|
wkt = '' |
|
else: |
|
wkt = value.wkt |
|
|
|
# Setting the parameter WKT with that of the transformed |
|
# geometry. |
|
self.params['wkt'] = wkt |
|
|
|
return render_to_string(self.template, self.params) |
|
|
|
def map_options(self): |
|
"Builds the map options hash for the OpenLayers template." |
|
|
|
# JavaScript construction utilities for the Bounds and Projection. |
|
def ol_bounds(extent): |
|
return 'new OpenLayers.Bounds(%s)' % str(extent) |
|
def ol_projection(srid): |
|
return 'new OpenLayers.Projection("EPSG:%s")' % srid |
|
|
|
# An array of the parameter name, the name of their OpenLayers |
|
# counterpart, and the type of variable they are. |
|
map_types = [('srid', 'projection', 'srid'), |
|
('display_srid', 'displayProjection', 'srid'), |
|
('units', 'units', str), |
|
('max_resolution', 'maxResolution', float), |
|
('max_extent', 'maxExtent', 'bounds'), |
|
('num_zoom', 'numZoomLevels', int), |
|
('max_zoom', 'maxZoomLevels', int), |
|
('min_zoom', 'minZoomLevel', int), |
|
] |
|
|
|
# Building the map options hash. |
|
map_options = {} |
|
for param_name, js_name, option_type in map_types: |
|
if self.params.get(param_name, False): |
|
if option_type == 'srid': |
|
value = ol_projection(self.params[param_name]) |
|
elif option_type == 'bounds': |
|
value = ol_bounds(self.params[param_name]) |
|
elif option_type in (float, int): |
|
value = self.params[param_name] |
|
elif option_type in (str,): |
|
value = '"%s"' % self.params[param_name] |
|
else: |
|
raise TypeError |
|
map_options[js_name] = value |
|
return map_options
|
|
|