OpenLayers示例代码：符号与WebGL
OpenLayers示例代码：符号与WebGL
<!DOCTYPE html>
<html>
<head>
<title>Symbols with WebGL</title>
<link rel="stylesheet" href="https://openlayers.org/en/v4.0.1/css/ol.css" type="text/css">
<!-- The line below is only needed for old environments like Internet Explorer and Android 4.x -->
<script src="https://cdn.polyfill.io/v2/polyfill.min.js?features=requestAnimationFrame,Element.prototype.classList,URL"></script>
<script src="https://openlayers.org/en/v4.0.1/build/ol.js"></script>
</head>
<body>
<div id="map" class="map"></div>
<script>
var atlasManager = new ol.style.AtlasManager({
// we increase the initial size so that all symbols fit into
// a single atlas image
initialSize: 512
});
var symbolInfo = [{
opacity: 1.0,
scale: 1.0,
fillColor: 'rgba(255, 153, 0, 0.4)',
strokeColor: 'rgba(255, 204, 0, 0.2)'
}, {
opacity: 0.75,
scale: 1.25,
fillColor: 'rgba(70, 80, 224, 0.4)',
strokeColor: 'rgba(12, 21, 138, 0.2)'
}, {
opacity: 0.5,
scale: 1.5,
fillColor: 'rgba(66, 150, 79, 0.4)',
strokeColor: 'rgba(20, 99, 32, 0.2)'
}, {
opacity: 1.0,
scale: 1.0,
fillColor: 'rgba(176, 61, 35, 0.4)',
strokeColor: 'rgba(145, 43, 20, 0.2)'
}];
var radiuses = [3, 6, 9, 15, 19, 25];
var symbolCount = symbolInfo.length * radiuses.length * 2;
var symbols = [];
var i, j;
for (i = 0; i < symbolInfo.length; ++i) {
var info = symbolInfo[i];
for (j = 0; j < radiuses.length; ++j) {
// circle symbol
symbols.push(new ol.style.Circle({
opacity: info.opacity,
scale: info.scale,
radius: radiuses[j],
fill: new ol.style.Fill({
color: info.fillColor
}),
stroke: new ol.style.Stroke({
color: info.strokeColor,
width: 1
}),
// by passing the atlas manager to the symbol,
// the symbol will be added to an atlas
atlasManager: atlasManager
}));
// star symbol
symbols.push(new ol.style.RegularShape({
points: 8,
opacity: info.opacity,
scale: info.scale,
radius: radiuses[j],
radius2: radiuses[j] * 0.7,
angle: 1.4,
fill: new ol.style.Fill({
color: info.fillColor
}),
stroke: new ol.style.Stroke({
color: info.strokeColor,
width: 1
}),
atlasManager: atlasManager
}));
}
}
var featureCount = 50000;
var features = new Array(featureCount);
var feature, geometry;
var e = 25000000;
for (i = 0; i < featureCount; ++i) {
geometry = new ol.geom.Point(
[2 * e * Math.random() - e, 2 * e * Math.random() - e]);
feature = new ol.Feature(geometry);
feature.setStyle(
new ol.style.Style({
image: symbols[i % symbolCount]
})
);
features[i] = feature;
}
var vectorSource = new ol.source.Vector({
features: features
});
var vector = new ol.layer.Vector({
source: vectorSource
});
var map = new ol.Map({
renderer: /** @type {ol.renderer.Type} */ ('webgl'),
layers: [vector],
target: document.getElementById('map'),
view: new ol.View({
center: [0, 0],
zoom: 4
})
});
</script>
</body>
</html>
说明：
OpenLayers示例代码：符号与WebGL
