#805 - all geometries now know how to rotate - see the examples/rotate-features.html for geometry.rotate in action

git-svn-id: http://svn.openlayers.org/trunk/openlayers@3602 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Geometry/Point.js

@@ -132,6 +132,22 @@ OpenLayers.Geometry.Point.prototype =
         this.y = this.y + y;
     },
 
+    /**
+     * APIMethod: rotate
+     * Rotate a point around another
+     *
+     * Parameters:
+     * angle - {Float} Rotation angle in radians (measured counterclockwise
+     *                 from the positive x-axis)
+     * origin - {OpenLayers.Geometry.Point} Center point for the rotation
+     */
+    rotate: function(angle, origin) {
+        var radius = this.distanceTo(origin);
+        var theta = angle + Math.atan2(this.y - origin.y, this.x - origin.x);
+        this.x = origin.x + (radius * Math.cos(theta));
+        this.y = origin.y + (radius * Math.sin(theta));
+    },
+
     /** @final @type String */
     CLASS_NAME: "OpenLayers.Geometry.Point"
 });