Give precedence to feature style

src/ol/style/defaultsstyle.js

@@ -0,0 +1,43 @@
+goog.provide('ol.style.defaults');
+
+goog.require('ol.style.Circle');
+goog.require('ol.style.Fill');
+goog.require('ol.style.Stroke');
+goog.require('ol.style.Style');
+
+
+/**
+ * @param {ol.Feature} feature Feature.
+ * @param {number} resolution Resolution.
+ * @return {Array.<ol.style.Style>} Style.
+ */
+ol.style.defaults.styleFunction = function(feature, resolution) {
+  var fill = new ol.style.Fill({
+    color: 'rgba(255,255,255,0.4)'
+  });
+  var stroke = new ol.style.Stroke({
+    color: '#3399CC',
+    width: 1.25
+  });
+  var styles = [
+    new ol.style.Style({
+      image: new ol.style.Circle({
+        fill: fill,
+        stroke: stroke,
+        radius: 5
+      }),
+      fill: fill,
+      stroke: stroke
+    })
+  ];
+
+  // now that we've run it the first time,
+  // replace the function with a constant version
+  ol.style.defaults.styleFunction =
+      /** @type {function(this:ol.Feature):Array.<ol.style.Style>} */(
+      function(resolution) {
+        return styles;
+      });
+
+  return styles;
+};

src/ol/style/style.js

@@ -1,5 +1,7 @@
 goog.provide('ol.style.Style');
 
+goog.require('goog.asserts');
+goog.require('goog.functions');
 goog.require('ol.style.Fill');
 goog.require('ol.style.Image');
 
@@ -93,3 +95,47 @@ ol.style.Style.prototype.getText = function() {
 ol.style.Style.prototype.getZIndex = function() {
   return this.zIndex_;
 };
+
+
+/**
+ * A function that takes an {@link ol.Feature} and a `{number}` representing
+ * the view's resolution. The function should return an array of
+ * {@link ol.style.Style}. This way e.g. a vector layer can be styled.
+ *
+ * @typedef {function(ol.Feature, number): Array.<ol.style.Style>}
+ * @api
+ */
+ol.style.StyleFunction;
+
+
+/**
+ * Convert the provided object into a style function.  Functions passed through
+ * unchanged.  Arrays of ol.style.Style or single style objects wrapped in a
+ * new style function.
+ * @param {ol.style.StyleFunction|Array.<ol.style.Style>|ol.style.Style} obj
+ *     A style function, a single style, or an array of styles.
+ * @return {ol.style.StyleFunction} A style function.
+ */
+ol.style.createStyleFunction = function(obj) {
+  /**
+   * @type {ol.style.StyleFunction}
+   */
+  var styleFunction;
+
+  if (goog.isFunction(obj)) {
+    styleFunction = /** @type {ol.style.StyleFunction} */ (obj);
+  } else {
+    /**
+     * @type {Array.<ol.style.Style>}
+     */
+    var styles;
+    if (goog.isArray(obj)) {
+      styles = obj;
+    } else {
+      goog.asserts.assertInstanceof(obj, ol.style.Style);
+      styles = [obj];
+    }
+    styleFunction = goog.functions.constant(styles);
+  }
+  return styleFunction;
+};