Add ol.control.KeyboardZoom

src/ol/control/keyboardzoom.js

@@ -0,0 +1,42 @@
+goog.provide('ol.control.KeyboardZoom');
+
+goog.require('goog.events.KeyCodes');
+goog.require('goog.events.KeyHandler.EventType');
+goog.require('ol.Control');
+
+
+
+/**
+ * @constructor
+ * @extends {ol.Control}
+ */
+ol.control.KeyboardZoom = function() {
+  goog.base(this);
+};
+goog.inherits(ol.control.KeyboardZoom, ol.Control);
+
+
+/**
+ * @inheritDoc
+ */
+ol.control.KeyboardZoom.prototype.handleMapBrowserEvent =
+    function(mapBrowserEvent) {
+  if (mapBrowserEvent.type == goog.events.KeyHandler.EventType.KEY) {
+    var keyEvent = /** @type {goog.events.KeyEvent} */
+        mapBrowserEvent.browserEvent;
+    var charCode = keyEvent.charCode;
+    if (charCode == '+'.charCodeAt(0) || charCode == '-'.charCodeAt(0)) {
+      var map = mapBrowserEvent.map;
+      // FIXME shouldn't use typecast here, better to check that map is defined
+      var resolution = /** @type {number} */ map.getResolution();
+      if (charCode == '+'.charCodeAt(0)) {
+        resolution = resolution / 2;
+      } else if (charCode == '-'.charCodeAt(0)) {
+        resolution = 2 * resolution;
+      }
+      map.setResolution(resolution);
+      keyEvent.preventDefault();
+      mapBrowserEvent.preventDefault();
+    }
+  }
+};