Openlayers实现扩散的动态点(水纹效果)
本文实例为大家分享了Openlayers实现扩散的动态点的具体代码,供大家参考,具体内容如下
在openlayers中制作危险源标识可以需要动态扩散的点(有很多种方法 可以加入jpg动图,也可以写css动画) 这里提供一种思路用openlayer自带的方法写 并给予详细的方法注释供初学者学习 (所有jar包都是在线的代码可以复制过去直接用)
<!DOCTYPE html> <html> <head> <title>Icon Symbolizer</title> <link rel="stylesheet" href="https://openlayers.org/en/v3.20.1/css/ol.css" rel="external nofollow" type="text/css"> <script src="https://cdn.polyfill.io/v2/polyfill.min.js?features=requestAnimationFrame,Element.prototype.classList,URL"></script> <script src="https://openlayers.org/en/v3.20.1/build/ol.js"></script> <script src="https://code.jquery.com/jquery-2.2.3.min.js"></script> <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css" rel="external nofollow" > <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js"></script> <style> #map { position: relative; } #popup { cursor: pointer; } </style> </head> <body> <div id="map" class="map"></div> <div id="styleType"> </div> <script> //水纹扩散 var bingMap = new ol.layer.Tile({ source :new ol.source.XYZ({ crossOrigin: 'anonymous', url:'http://www.google.cn/maps/vt?lyrs=m@189&gl=cn&x={x}&y={y}&z={z}' }) }); var map = new ol.Map({ layers: [bingMap], target: 'map', view: new ol.View({ center: ol.proj.transform([112.91, 28.21], 'EPSG:4326', 'EPSG:3857'), zoom: 5 }) }); var source = new ol.source.Vector({ wrapX: false }); var vector = new ol.layer.Vector({ source: source }); map.addLayer(vector); function addRandomFeature() { var geom = new ol.geom.Point(ol.proj.fromLonLat([112.91, 28.21])); var feature = new ol.Feature(geom); source.addFeature(feature); } var duration = 1000; function flash(feature) { var start = new Date().getTime(); //进行地图水波渲染 var listenerKey = map.on('postcompose', animate); function animate(event) { //获取几何图形 var vectorContext = event.vectorContext; //获取当前渲染帧状态 var frameState = event.frameState; //添加一个OpenLayers.Geometry几何对象 var flashGeom = feature.getGeometry().clone(); //渲染帧状已占时间 var elapsed = frameState.time - start; //已占比率 var elapsedRatio = elapsed / duration; // radius半径为5结束为30 var radius = ol.easing.easeOut(elapsedRatio) * 25 + 5; //不透渐变消失 var opacity = ol.easing.easeOut(1 - elapsedRatio); //Circle样式 var style = new ol.style.Style({ image: new ol.style.Circle({ radius: radius, stroke: new ol.style.Stroke({ color: 'rgba(255, 0, 0, ' + opacity + ')', width: 1 + opacity }) }) }); //给几何图形添加样式 vectorContext.setStyle(style); //将几何体渲染到画布中 vectorContext.drawGeometry(flashGeom); if (elapsed > duration) { start = frameState.time ; ; } //请求地图渲染(在下一个动画帧处) map.render(); } } //数据源添加图层 source.on('addfeature', function(e) { flash(e.feature); }); addRandomFeature() </script> </body> </html>
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