[英]Drawing animated openlayers linestring path
我在http://jerusalem.com/map#!/tour/the_way_of_the_cross/location/abu_jaafar上看到了一个令人印象深刻的映射示例,有人可以使用openlayers在点绘制路径上进行类似的动画吗?
下面的小提琴显示了线串http://jsfiddle.net/pwuVz/58/,但是我需要能够对线串本身进行动画处理,以便不直接绘制该线串。
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);
您可以通过一次仅绘制线条的一部分来对其进行动画处理。 这是您可以执行的一种方法:
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
参数指定您希望动画持续多长时间(以毫秒为单位),而steps
指定要将动画划分为多少步。 fn
是一个动画完成后将执行的回调。
这是一个演示此过程的jsFiddle演示 。
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