Javascript 绘制动画openlayers线条字符串路径

我在上看到了一个令人印象深刻的映射示例，有人知道如何使用openlayers在点的绘制路径上创建类似的动画吗

下面的小提琴显示了线串，但我需要的是能够动画线串本身，使字符串不直接绘制

var map = new OpenLayers.Map( 'map', {theme:null,
                    controls:[new OpenLayers.Control.Navigation()]} );
            layer = new OpenLayers.Layer.WMS( "OpenLayers WMS",
                    "http://vmap0.tiles.osgeo.org/wms/vmap0",
                    {layers: 'basic'} );
            map.addLayer(layer);
            map.setCenter([3, 49], 5);

var startPt=new OpenLayers.Geometry.Point( 2, 45);
var endPt=new OpenLayers.Geometry.Point(7,55);

//make the line:
var line=new OpenLayers.Geometry.LineString([startPt, endPt]);

//style
var style={strokeColor:"#0500bd", strokeWidth:15, strokeOpacity: 0.5,  strokeColor: '#0000ff'};
//make vector 
var fea=new OpenLayers.Feature.Vector(line, {}, style);

//make vectorLayer
var vec= new OpenLayers.Layer.Vector();

//add the feature
vec.addFeatures([fea]);

//add to map
map.addLayer(vec);

setTimeout(function() {

      var startPt=new OpenLayers.Geometry.Point( 7, 55);
var endPt=new OpenLayers.Geometry.Point(13,52);

//make the line:
var line=new OpenLayers.Geometry.LineString([startPt, endPt]);

//style
var style={strokeColor:"#0500bd", strokeWidth:15, strokeOpacity: 0.5,  strokeColor: '#0000ff'};
//make vector 
var fea=new OpenLayers.Feature.Vector(line, {}, style);

//make vectorLayer
var vec= new OpenLayers.Layer.Vector();

//add the feature
vec.addFeatures([fea]);

//add to map
map.addLayer(vec);

}, 2000);

---

通过一次只绘制线的一部分，可以对其设置动画。以下是一种方法：

function drawAnimatedLine(startPt, endPt, style, steps, time, fn) {
    var directionX = (endPt.x - startPt.x) / steps;
    var directionY = (endPt.y - startPt.y) / steps;
    var i = 0;
    var prevLayer;
    var ivlDraw = setInterval(function () {
        if (i > steps) {
            clearInterval(ivlDraw);
            if (fn) fn();
            return;
        }
        var newEndPt = new OpenLayers.Geometry.Point(startPt.x + i * directionX, startPt.y + i * directionY);
        var line = new OpenLayers.Geometry.LineString([startPt, newEndPt]);
        var fea = new OpenLayers.Feature.Vector(line, {}, style);
        var vec = new OpenLayers.Layer.Vector();
        vec.addFeatures([fea]);
        map.addLayer(vec);
        if(prevLayer) map.removeLayer(prevLayer);
        prevLayer = vec;
        i++;
    }, time / steps);
}

time

参数指定希望动画持续多长时间（以毫秒为单位），而

steps

指定希望将动画分成多少个步骤

fn

是一个回调，将在动画完成时执行

---

这里有一个例子来演示这一点。

你好，Peter，我想知道JSFIDLE是否仍然有效，或者我必须做一些特殊的事情来观看演示？我只在右下角看到一个绿色边框框。@JuanCarlosOropeza谢谢你的通知。我更新了JSFIDLE。问题是OpenLayers脚本的外部链接已断开。@PeterOlson您好，我们如何使用您的代码，同时使用一组行字符串，我们只能使用几个点而不是很多点