From aab5c8472c4377f98a84f1b9ee52a3e61a193307 Mon Sep 17 00:00:00 2001
From: Tim Schaub <tim.schaub@gmail.com>
Date: Wed, 26 Jun 2013 17:51:02 -0600
Subject: [PATCH] Update example to use expression parsing

---
 examples/kml-timezones.html |  2 +-
 examples/kml-timezones.js   | 17 ++++++++++++-----
 2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/examples/kml-timezones.html b/examples/kml-timezones.html
index 56e0d8a92d..28ba047095 100644
--- a/examples/kml-timezones.html
+++ b/examples/kml-timezones.html
@@ -39,7 +39,7 @@
           <h4 id="title">Timezones in KML</h4>
           <p id="shortdesc">Demonstrates rendering timezones from KML.</p>
           <div id="docs">
-            <p>This example parses a KML file and renders the features as a vector layer.  Note that currently the <code>kml:StyleMap</code> elements are not parsed, so the layer is given a <code>ol.style.Style</code> manually.  The timezones are filled yellow with an opacity calculated based on the current offset to local noon.</p>
+            <p>This example parses a KML file and renders the features as a vector layer.  The layer is given a <code>ol.style.Style</code> that fills timezones yellow with an opacity calculated based on the current offset to local noon.</p>
             <p>See the <a href="kml-timezones.js" target="_blank">kml-timezones.js source</a> to see how this is done.</p>
           </div>
           <div id="tags">KML, vector, style</div>
diff --git a/examples/kml-timezones.js b/examples/kml-timezones.js
index 9979d8196c..0dd9af9d1d 100644
--- a/examples/kml-timezones.js
+++ b/examples/kml-timezones.js
@@ -1,7 +1,7 @@
-goog.require('ol.Expression');
 goog.require('ol.Map');
 goog.require('ol.RendererHint');
 goog.require('ol.View2D');
+goog.require('ol.expr');
 goog.require('ol.layer.TileLayer');
 goog.require('ol.layer.Vector');
 goog.require('ol.parser.KML');
@@ -12,8 +12,15 @@ goog.require('ol.style.Polygon');
 goog.require('ol.style.Rule');
 goog.require('ol.style.Style');
 
-// calculate opacity based on difference from local noon
-function getOpacity(feature) {
+
+/**
+ * Register a function to be used in a symbolizer.  Here we want the opacity
+ * of polygons to be based on the offset from local noon.  For example, a
+ * timezone where it is currently noon would have an opacity of 1.  And a
+ * timezone where it is currently 6:00am would have an opacity of 0.5.
+ */
+ol.expr.register('getOpacity', function() {
+  var feature = this;
   var opacity = 0;
   var name = feature.get('name'); // e.g. GMT -08:30
   var match = name.match(/([-+]\d{2}):(\d{2})$/);
@@ -31,7 +38,7 @@ function getOpacity(feature) {
     opacity = 1 - offset / 12;
   }
   return opacity;
-}
+});
 
 var style = new ol.style.Style({rules: [
   new ol.style.Rule({
@@ -39,7 +46,7 @@ var style = new ol.style.Style({rules: [
       new ol.style.Polygon({
         fillColor: '#ffff33',
         strokeColor: '#ffffff',
-        opacity: new ol.Expression('getOpacity(this)')
+        opacity: ol.expr.parse('getOpacity()')
       })
     ]
   })