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<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0">
<meta name="apple-mobile-web-app-capable" content="yes">
<title>OpenLayers Mousewheel Interval Example</title>
<link rel="stylesheet" href="../theme/default/style.css" type="text/css">
<link rel="stylesheet" href="style.css" type="text/css">
<script src="../lib/OpenLayers.js"></script>
<script type="text/javascript">
var map, layer;
function setCumulative() {
var nav = map.getControlsByClass("OpenLayers.Control.Navigation")[0];
var cumulative = document.getElementById("cumulative");
nav.handlers.wheel.cumulative = cumulative.checked;
}
function init(){
map = new OpenLayers.Map( 'map', {controls: [
new OpenLayers.Control.Navigation(
{mouseWheelOptions: {interval: 100}}
),
new OpenLayers.Control.PanZoom(),
new OpenLayers.Control.ArgParser(),
new OpenLayers.Control.Attribution()
]} );
layer = new OpenLayers.Layer.WMS( "OpenLayers WMS",
"http://vmap0.tiles.osgeo.org/wms/vmap0",
{layers: 'basic'} );
map.addLayer(layer);
map.zoomToMaxExtent();
}
</script>
</head>
<body onload="init()">
<h1 id="title">OpenLayers Mousewheel Interval Example</h1>
<div id="tags">
performance, zoom by wheel
</div>
<div id="shortdesc">Let OpenLayers send less tile requests to the server when wheel-zooming.</div>
<div id="map" class="smallmap"></div>
<div id="docs">
<p>This example shows how to configure the Navigation control to use
the mousewheel in a less server resource consuming way: as long as you
spin the mousewheel, no request will be sent to the server. Instead,
the zoomlevel delta will be recorded. After a delay (in this example
100ms), a zoom action with the cumulated delta will be performed.</p>
<div>
<input id="cumulative" type="checkbox" checked="checked"
onchange="setCumulative()"/>
<label for="cumulative">Cumulative mode. If this mode is deactivated,
only one zoom event will be performed after the delay.</label>
</div>
</div>
</body>
</html>
|
