c36b897878
Because this method is called by OpenLayers.Function.bindAsEventListener, which conditionally assigns window.event already, e cannot be null or undefined here.
255 lines
8.6 KiB
JavaScript
255 lines
8.6 KiB
JavaScript
/* Copyright (c) 2006-2012 by OpenLayers Contributors (see authors.txt for
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* full list of contributors). Published under the 2-clause BSD license.
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* See license.txt in the OpenLayers distribution or repository for the
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* full text of the license. */
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/**
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* @requires OpenLayers/Handler.js
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*/
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/**
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* Class: OpenLayers.Handler.MouseWheel
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* Handler for wheel up/down events.
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*
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* Inherits from:
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* - <OpenLayers.Handler>
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*/
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OpenLayers.Handler.MouseWheel = OpenLayers.Class(OpenLayers.Handler, {
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/**
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* Property: wheelListener
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* {function}
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*/
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wheelListener: null,
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/**
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* Property: interval
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* {Integer} In order to increase server performance, an interval (in
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* milliseconds) can be set to reduce the number of up/down events
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* called. If set, a new up/down event will not be set until the
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* interval has passed.
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* Defaults to 0, meaning no interval.
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*/
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interval: 0,
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/**
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* Property: delta
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* {Integer} When interval is set, delta collects the mousewheel z-deltas
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* of the events that occur within the interval.
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* See also the cumulative option
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*/
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delta: 0,
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/**
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* Property: cumulative
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* {Boolean} When interval is set: true to collect all the mousewheel
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* z-deltas, false to only record the delta direction (positive or
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* negative)
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*/
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cumulative: true,
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/**
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* Constructor: OpenLayers.Handler.MouseWheel
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*
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* Parameters:
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* control - {<OpenLayers.Control>}
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* callbacks - {Object} An object containing a single function to be
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* called when the drag operation is finished.
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* The callback should expect to recieve a single
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* argument, the point geometry.
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* options - {Object}
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*/
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initialize: function(control, callbacks, options) {
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OpenLayers.Handler.prototype.initialize.apply(this, arguments);
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this.wheelListener = OpenLayers.Function.bindAsEventListener(
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this.onWheelEvent, this
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);
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},
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/**
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* Method: destroy
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*/
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destroy: function() {
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OpenLayers.Handler.prototype.destroy.apply(this, arguments);
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this.wheelListener = null;
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},
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/**
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* Mouse ScrollWheel code thanks to http://adomas.org/javascript-mouse-wheel/
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*/
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/**
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* Method: onWheelEvent
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* Catch the wheel event and handle it xbrowserly
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*
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* Parameters:
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* e - {Event}
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*/
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onWheelEvent: function(e){
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// make sure we have a map and check keyboard modifiers
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if (!this.map || !this.checkModifiers(e)) {
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return;
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}
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// Ride up the element's DOM hierarchy to determine if it or any of
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// its ancestors was:
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// * specifically marked as scrollable (CSS overflow property)
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// * one of our layer divs or a div marked as scrollable
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// ('olScrollable' CSS class)
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// * the map div
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//
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var overScrollableDiv = false;
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var allowScroll = false;
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var overMapDiv = false;
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var elem = OpenLayers.Event.element(e);
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while((elem != null) && !overMapDiv && !overScrollableDiv) {
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if (!overScrollableDiv) {
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try {
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var overflow;
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if (elem.currentStyle) {
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overflow = elem.currentStyle["overflow"];
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} else {
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var style =
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document.defaultView.getComputedStyle(elem, null);
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overflow = style.getPropertyValue("overflow");
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}
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overScrollableDiv = ( overflow &&
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(overflow == "auto") || (overflow == "scroll") );
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} catch(err) {
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//sometimes when scrolling in a popup, this causes
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// obscure browser error
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}
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}
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if (!allowScroll) {
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allowScroll = OpenLayers.Element.hasClass(elem, 'olScrollable');
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if (!allowScroll) {
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for (var i = 0, len = this.map.layers.length; i < len; i++) {
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// Are we in the layer div? Note that we have two cases
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// here: one is to catch EventPane layers, which have a
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// pane above the layer (layer.pane)
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var layer = this.map.layers[i];
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if (elem == layer.div || elem == layer.pane) {
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allowScroll = true;
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break;
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}
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}
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}
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}
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overMapDiv = (elem == this.map.div);
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elem = elem.parentNode;
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}
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// Logic below is the following:
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//
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// If we are over a scrollable div or not over the map div:
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// * do nothing (let the browser handle scrolling)
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//
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// otherwise
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//
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// If we are over the layer div or a 'olScrollable' div:
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// * zoom/in out
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// then
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// * kill event (so as not to also scroll the page after zooming)
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//
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// otherwise
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//
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// Kill the event (dont scroll the page if we wheel over the
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// layerswitcher or the pan/zoom control)
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//
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if (!overScrollableDiv && overMapDiv) {
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if (allowScroll) {
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var delta = 0;
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if (e.wheelDelta) {
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delta = e.wheelDelta;
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if (delta % 160 === 0) {
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// opera have steps of 160 instead of 120
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delta = delta * 0.75;
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}
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delta = delta / 120;
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} else if (e.detail) {
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// detail in Firefox on OS X is 1/3 of Windows
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// so force delta 1 / -1
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delta = - (e.detail / Math.abs(e.detail));
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}
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this.delta = this.delta + delta;
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if(this.interval) {
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window.clearTimeout(this._timeoutId);
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// store e because window.event might change during delay
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var evt = OpenLayers.Util.extend({}, e);
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this._timeoutId = window.setTimeout(
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OpenLayers.Function.bind(function(){
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this.wheelZoom(evt);
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}, this),
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this.interval
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);
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} else {
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this.wheelZoom(e);
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}
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}
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OpenLayers.Event.stop(e);
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}
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},
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/**
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* Method: wheelZoom
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* Given the wheel event, we carry out the appropriate zooming in or out,
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* based on the 'wheelDelta' or 'detail' property of the event.
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*
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* Parameters:
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* e - {Event}
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*/
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wheelZoom: function(e) {
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var delta = this.delta;
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this.delta = 0;
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if (delta) {
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e.xy = this.map.events.getMousePosition(e);
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if (delta < 0) {
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this.callback("down", [e, this.cumulative ? delta : -1]);
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} else {
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this.callback("up", [e, this.cumulative ? delta : 1]);
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}
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}
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},
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/**
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* Method: activate
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*/
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activate: function (evt) {
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if (OpenLayers.Handler.prototype.activate.apply(this, arguments)) {
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//register mousewheel events specifically on the window and document
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var wheelListener = this.wheelListener;
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OpenLayers.Event.observe(window, "DOMMouseScroll", wheelListener);
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OpenLayers.Event.observe(window, "mousewheel", wheelListener);
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OpenLayers.Event.observe(document, "mousewheel", wheelListener);
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return true;
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} else {
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return false;
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}
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},
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/**
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* Method: deactivate
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*/
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deactivate: function (evt) {
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if (OpenLayers.Handler.prototype.deactivate.apply(this, arguments)) {
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// unregister mousewheel events specifically on the window and document
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var wheelListener = this.wheelListener;
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OpenLayers.Event.stopObserving(window, "DOMMouseScroll", wheelListener);
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OpenLayers.Event.stopObserving(window, "mousewheel", wheelListener);
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OpenLayers.Event.stopObserving(document, "mousewheel", wheelListener);
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return true;
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} else {
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return false;
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}
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},
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CLASS_NAME: "OpenLayers.Handler.MouseWheel"
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});
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