OpenLayers示例代码：渲染canvas的几何
OpenLayers示例代码：渲染canvas的几何
<!DOCTYPE html>
<html>
<head>
<title>Render geometries to a canvas</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>
<canvas id="canvas"></canvas>
<script>
var canvas = document.getElementById('canvas');
var vectorContext = ol.render.toContext(canvas.getContext('2d'), {size: [100, 100]});
var fill = new ol.style.Fill({color: 'blue'});
var stroke = new ol.style.Stroke({color: 'black'});
var style = new ol.style.Style({
fill: fill,
stroke: stroke,
image: new ol.style.Circle({
radius: 10,
fill: fill,
stroke: stroke
})
});
vectorContext.setStyle(style);
vectorContext.drawGeometry(new ol.geom.LineString([[10, 10], [90, 90]]));
vectorContext.drawGeometry(new ol.geom.Polygon([[[2, 2], [98, 2], [2, 98], [2, 2]]]));
vectorContext.drawGeometry(new ol.geom.Point([88, 88]));
</script>
</body>
</html>
说明：
OpenLayers示例代码：渲染canvas的几何
