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

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

docs/ref/contrib/gis/forms-api.txt

@@ -0,0 +1,165 @@
+.. _ref-gis-forms-api:
+
+===================
+GeoDjango Forms API
+===================
+
+.. module:: django.contrib.gis.forms
+   :synopsis: GeoDjango forms API.
+
+.. versionadded:: 1.6
+
+GeoDjango provides some specialized form fields and widgets in order to visually 
+display and edit geolocalized data on a map. By default, they use
+`OpenLayers`_-powered maps, with a base WMS layer provided by `Metacarta`_.
+
+.. _OpenLayers: http://openlayers.org/
+.. _Metacarta: http://metacarta.com/
+
+Field arguments
+===============
+In addition to the regular :ref:`form field arguments <core-field-arguments>`,
+GeoDjango form fields take the following optional arguments.
+
+``srid``
+~~~~~~~~
+
+.. attribute:: Field.srid
+
+    This is the SRID code that the field value should be transformed to. For
+    example, if the map widget SRID is different from the SRID more generally
+    used by your application or database, the field will automatically convert
+    input values into that SRID.
+
+``geom_type``
+~~~~~~~~~~~~~
+
+.. attribute:: Field.geom_type
+
+    You generally shouldn't have to set or change that attribute which should
+    be setup depending on the field class. It matches the OpenGIS standard
+    geometry name.
+
+Form field classes
+==================
+
+``GeometryField``
+~~~~~~~~~~~~~~~~~
+
+.. class:: GeometryField
+
+``PointField``
+~~~~~~~~~~~~~~
+
+.. class:: PointField
+
+``LineStringField``
+~~~~~~~~~~~~~~~~~~~
+
+.. class:: LineStringField
+
+``PolygonField``
+~~~~~~~~~~~~~~~~
+
+.. class:: PolygonField
+
+``MultiPointField``
+~~~~~~~~~~~~~~~~~~~
+
+.. class:: MultiPointField
+
+``MultiLineStringField``
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. class:: MultiLineStringField
+
+``MultiPolygonField``
+~~~~~~~~~~~~~~~~~~~~~
+
+.. class:: MultiPolygonField
+
+``GeometryCollectionField``
+~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. class:: GeometryCollectionField
+
+Form widgets
+============
+
+.. module:: django.contrib.gis.widgets
+   :synopsis: GeoDjango widgets API.
+
+GeoDjango form widgets allow you to display and edit geographic data on a
+visual map.
+Note that none of the currently available widgets supports 3D geometries, hence
+geometry fields will fallback using a simple ``Textarea`` widget for such data.
+
+Widget attributes
+~~~~~~~~~~~~~~~~~
+
+GeoDjango widgets are template-based, so their attributes are mostly different
+from other Django widget attributes.
+
+
+.. attribute:: BaseGeometryWidget.geom_type
+
+    The OpenGIS geometry type, generally set by the form field.
+
+.. attribute:: BaseGeometryWidget.map_height
+.. attribute:: BaseGeometryWidget.map_width
+
+    Height and width of the widget map (default is 400x600).
+
+.. attribute:: BaseGeometryWidget.map_srid
+
+    SRID code used by the map (default is 4326).
+
+.. attribute:: BaseGeometryWidget.display_wkt
+
+    Boolean value specifying if a textarea input showing the WKT representation
+    of the current geometry is visible, mainly for debugging purposes (default
+    is ``False``).
+
+.. attribute:: BaseGeometryWidget.supports_3d
+
+    Indicates if the widget supports edition of 3D data (default is ``False``).
+
+.. attribute:: BaseGeometryWidget.template_name
+
+    The template used to render the map widget.
+
+You can pass widget attributes in the same manner that for any other Django
+widget. For example::
+
+    from django.contrib.gis import forms
+
+    class MyGeoForm(forms.Form):
+        point = forms.PointField(widget=
+            forms.OSMWidget(attrs={'map_width': 800, 'map_height': 500}))
+
+Widget classes
+~~~~~~~~~~~~~~
+
+``BaseGeometryWidget``
+
+.. class:: BaseGeometryWidget
+
+    This is an abstract base widget containing the logic needed by subclasses.
+    You cannot directly use this widget for a geometry field.
+    Note that the rendering of GeoDjango widgets is based on a template,
+    identified by the :attr:`template_name` class attribute.
+
+``OpenLayersWidget``
+
+.. class:: OpenLayersWidget
+
+    This is the default widget used by all GeoDjango form fields.
+    ``template_name`` is ``gis/openlayers.html``.
+
+``OSMWidget``
+
+.. class:: OSMWidget
+
+    This widget uses an OpenStreetMap base layer (Mapnik) to display geographic
+    objects on.
+    ``template_name`` is ``gis/openlayers-osm.html``.

docs/ref/contrib/gis/index.txt

@@ -18,6 +18,7 @@ of spatially enabled data.
    install/index
    model-api
    db-api
+   forms-api
    geoquerysets
    measure
    geos

docs/ref/forms/fields.txt

@@ -30,6 +30,8 @@ exception or returns the clean value::
     ...
     ValidationError: [u'Enter a valid email address.']
 
+.. _core-field-arguments:
+
 Core field arguments
 --------------------