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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 Paging Strategy 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, photos, paging;
OpenLayers.ProxyHost = (window.location.host == "localhost") ?
"/cgi-bin/proxy.cgi?url=" : "proxy.cgi?url=";
function init() {
map = new OpenLayers.Map('map', {
restrictedExtent: new OpenLayers.Bounds(-180, -90, 180, 90)
});
var base = new OpenLayers.Layer.WMS("Imagery",
["http://t1.hypercube.telascience.org/tiles?",
"http://t2.hypercube.telascience.org/tiles?",
"http://t3.hypercube.telascience.org/tiles?",
"http://t4.hypercube.telascience.org/tiles?"],
{layers: 'landsat7'}
);
var style = new OpenLayers.Style({
externalGraphic: "${img_url}",
pointRadius: 30
});
paging = new OpenLayers.Strategy.Paging();
photos = new OpenLayers.Layer.Vector("Photos", {
strategies: [new OpenLayers.Strategy.Fixed(), paging],
protocol: new OpenLayers.Protocol.HTTP({
url: "http://labs.metacarta.com/flickrbrowse/flickr.py/flickr",
params: {
format: "WFS",
sort: "interestingness-desc",
service: "WFS",
request: "GetFeatures",
srs: "EPSG:4326",
maxfeatures: 100,
bbox: [-180, -90, 180, 90]
},
format: new OpenLayers.Format.GML()
}),
styleMap: new OpenLayers.StyleMap(style)
});
map.addLayers([base, photos]);
photos.events.on({"featuresadded": updateButtons});
map.setCenter(new OpenLayers.LonLat(0, 0), 1);
}
function updateButtons() {
document.getElementById("prev").disabled = (paging.pageNum() < 1);
document.getElementById("next").disabled = (paging.pageNum() >= paging.pageCount() - 1);
document.getElementById("num").innerHTML = paging.pageNum() + 1;
document.getElementById("count").innerHTML = paging.pageCount();
}
</script>
</head>
<body onload="init()">
<h1 id="title">Paging Strategy Example</h1>
<div id="tags">
vector, feature, stylemap, wfs, paging, strategy, cleanup
</div>
<p id="shortdesc">
Uses a paging strategy to cache large batches of features and render a page at a time.
</p>
<div id="map" class="smallmap"></div>
Displaying page <span id="num">0</span> of <span id="count">...</span>
<button id="prev" disabled="disabled" onclick="paging.pagePrevious();">previous</button>
<button id="next" disabled="disabled" onclick="paging.pageNext();">next</button>
<br><br>
<div id="docs">
<p>The Paging strategy lets you apply client side paging for protocols
that do not support paging on the server. In this case, the protocol requests a
batch of 100 features, the strategy caches those and supplies a single
page at a time to the layer.</p>
</div>
</body>
</html>
|
