Basic support for text symbolizers

This adds basic label rendering for points and polygons to the
canvas renderer, and a text symbolizer to the style package.

examples/style-rules.js

@@ -4,13 +4,17 @@ goog.require('ol.RendererHint');
 goog.require('ol.View2D');
 goog.require('ol.control.defaults');
 goog.require('ol.filter.Filter');
+goog.require('ol.filter.Geometry');
+goog.require('ol.geom.GeometryType');
 goog.require('ol.layer.Vector');
 goog.require('ol.parser.GeoJSON');
 goog.require('ol.proj');
 goog.require('ol.source.Vector');
 goog.require('ol.style.Line');
 goog.require('ol.style.Rule');
+goog.require('ol.style.Shape');
 goog.require('ol.style.Style');
+goog.require('ol.style.Text');
 
 
 var style = new ol.style.Style({rules: [
@@ -42,6 +46,21 @@ var style = new ol.style.Style({rules: [
         opacity: 1
       })
     ]
+  }),
+  new ol.style.Rule({
+    filter: new ol.filter.Geometry(ol.geom.GeometryType.POINT),
+    symbolizers: [
+      new ol.style.Shape({
+        size: 40,
+        fillColor: '#013'
+      }),
+      new ol.style.Text({
+        color: '#bada55',
+        name: new ol.Expression('label'),
+        fontFamily: 'Calibri,sans-serif',
+        fontSize: 14
+      })
+    ]
   })
 ]});
 
@@ -114,6 +133,42 @@ vector.parseFeatures({
       'type': 'LineString',
       'coordinates': [[10000000, -10000000], [-10000000, -10000000]]
     }
+  }, {
+    'type': 'Feature',
+    'properties': {
+      'label': 'South'
+    },
+    'geometry': {
+      'type': 'Point',
+      'coordinates': [0, -6000000]
+    }
+  }, {
+    'type': 'Feature',
+    'properties': {
+      'label': 'West'
+    },
+    'geometry': {
+      'type': 'Point',
+      'coordinates': [-6000000, 0]
+    }
+  }, {
+    'type': 'Feature',
+    'properties': {
+      'label': 'North'
+    },
+    'geometry': {
+      'type': 'Point',
+      'coordinates': [0, 6000000]
+    }
+  }, {
+    'type': 'Feature',
+    'properties': {
+      'label': 'East'
+    },
+    'geometry': {
+      'type': 'Point',
+      'coordinates': [6000000, 0]
+    }
   }]
 }, new ol.parser.GeoJSON(), ol.proj.get('EPSG:3857'));