Fixed #5472 --Added OpenLayers-based widgets in contrib.gis

Largely inspired from django-floppyforms. Designed to not depend
on OpenLayers at code level.

1 files changed, 112 insertions, 0 deletions

diff --git a/django/contrib/gis/forms/widgets.py b/django/contrib/gis/forms/widgets.py
new file mode 100644
index 0000000000..d50c7c005a
--- /dev/null
+++ b/django/contrib/gis/forms/widgets.py
@@ -0,0 +1,112 @@
+from __future__ import unicode_literals
+
+import logging
+
+from django.conf import settings
+from django.contrib.gis import gdal
+from django.contrib.gis.geos import GEOSGeometry, GEOSException
+from django.forms.widgets import Widget
+from django.template import loader
+from django.utils import six
+from django.utils import translation
+
+logger = logging.getLogger('django.contrib.gis')
+
+
+class BaseGeometryWidget(Widget):
+    """
+    The base class for rich geometry widgets.
+    Renders a map using the WKT of the geometry.
+    """
+    geom_type = 'GEOMETRY'
+    map_srid = 4326
+    map_width = 600
+    map_height = 400
+    display_wkt = False
+
+    supports_3d = False
+    template_name = ''  # set on subclasses
+
+    def __init__(self, attrs=None):
+        self.attrs = {}
+        for key in ('geom_type', 'map_srid', 'map_width', 'map_height', 'display_wkt'):
+            self.attrs[key] = getattr(self, key)
+        if attrs:
+            self.attrs.update(attrs)
+
+    def render(self, name, value, attrs=None):
+        # If a string reaches here (via a validation error on another
+        # field) then just reconstruct the Geometry.
+        if isinstance(value, six.string_types):
+            try:
+                value = GEOSGeometry(value)
+            except (GEOSException, ValueError) as err:
+                logger.error(
+                    "Error creating geometry from value '%s' (%s)" % (
+                    value, err)
+                )
+                value = None
+
+        wkt = ''
+        if value:
+            # Check that srid of value and map match
+            if value.srid != self.map_srid:
+                try:
+                    ogr = value.ogr
+                    ogr.transform(self.map_srid)
+                    wkt = ogr.wkt
+                except gdal.OGRException as err:
+                    logger.error(
+                        "Error transforming geometry from srid '%s' to srid '%s' (%s)" % (
+                        value.srid, self.map_srid, err)
+                    )
+            else:
+                wkt = value.wkt
+
+        context = self.build_attrs(attrs,
+            name=name,
+            module='geodjango_%s' % name.replace('-','_'),  # JS-safe
+            wkt=wkt,
+            geom_type=gdal.OGRGeomType(self.attrs['geom_type']),
+            STATIC_URL=settings.STATIC_URL,
+            LANGUAGE_BIDI=translation.get_language_bidi(),
+        )
+        return loader.render_to_string(self.template_name, context)
+
+
+class OpenLayersWidget(BaseGeometryWidget):
+    template_name = 'gis/openlayers.html'
+    class Media:
+        js = (
+            'http://openlayers.org/api/2.11/OpenLayers.js',
+            'gis/js/OLMapWidget.js',
+        )
+
+
+class OSMWidget(BaseGeometryWidget):
+    """
+    An OpenLayers/OpenStreetMap-based widget.
+    """
+    template_name = 'gis/openlayers-osm.html'
+    default_lon = 5
+    default_lat = 47
+
+    class Media:
+        js = (
+            'http://openlayers.org/api/2.11/OpenLayers.js',
+            'http://www.openstreetmap.org/openlayers/OpenStreetMap.js',
+            'gis/js/OLMapWidget.js',
+        )
+
+    @property
+    def map_srid(self):
+        # Use the official spherical mercator projection SRID on versions
+        # of GDAL that support it; otherwise, fallback to 900913.
+        if gdal.HAS_GDAL and gdal.GDAL_VERSION >= (1, 7):
+            return 3857
+        else:
+            return 900913
+
+    def render(self, name, value, attrs=None):
+        return super(self, OSMWidget).render(name, value,
+            {'default_lon': self.default_lon, 'default_lat': self.default_lat})