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[英]Get layers by class (Vector) then refresh does not work using Openlayer 2.14
[英]How to improve OpenLayer Vector layers refresh for 200 elements?
我想開發一種結合了jquery-ui滑塊組件和OpenLayer庫的時間表。
我只是使用具有規則樣式的OpenLayers的Vector層。
map = new OpenLayers.Map('map', {maxResolution:'auto'});
var wms = new OpenLayers.Layer.WMS( "OpenLayers WMS",
"http://vmap0.tiles.osgeo.org/wms/vmap0",
{layers: 'basic'} );
map.addLayer(wms);
map.setCenter(new OpenLayers.LonLat(0, 0), 0);
// create 20 random features with a random type attribute. The
// type attribute is a value between 0 and 2.
var features = new Array(20);
for (var i=0; i<20; i++) {
features[i] = new OpenLayers.Feature.Vector(
new OpenLayers.Geometry.Point(Math.random()*360-180, Math.random()*180-90),
{type: parseInt(Math.random()*80)}
);
}
var style = new OpenLayers.Style(
{
graphicHeight: 20,
graphicYOffset: -19,
rotation: "${angle}"
},
{
rules: [ new OpenLayers.Rule({
filter: new OpenLayers.Filter.Comparison({
type: OpenLayers.Filter.Comparison.LESS_THAN,
property: "value",
value: 20
}),
symbolizer: {
externalGraphic: "http://dev.openlayers.org/releases/OpenLayers-2.13.1/img/marker-blue.png"
}
}),
new OpenLayers.Rule({
filter: new OpenLayers.Filter.Comparison({
type: OpenLayers.Filter.Comparison.BETWEEN,
property: "value",
lowerBoundary: 20,
upperBoundary: 40
}),
symbolizer: {
externalGraphic: "http://dev.openlayers.org/releases/OpenLayers-2.13.1/img/marker-green.png"
}
}),
new OpenLayers.Rule({
filter: new OpenLayers.Filter.Comparison({
type: OpenLayers.Filter.Comparison.GREATER_THAN,
property: "value",
value: 40
}),
symbolizer: {
externalGraphic: "http://dev.openlayers.org/releases/OpenLayers-2.13.1/img/marker-gold.png"
}
})
]
}
);
layer = new OpenLayers.Layer.Vector('Points', {
styleMap: new OpenLayers.StyleMap(style)
});
layer.addFeatures(features);
map.addLayer(layer);
我通過jquery-ui滑塊的slide事件更改顯示的值。
$( "#slider" ).slider({
value:0,
min: 0,
max: 100,
step: 1,
slide: function( event, ui ) {
var end = false;
//launched.push(ui.value);
$( "#value" ).val( ui.value );
function redraw(){
//launched.pop();
for(var i = 0 ; i < features.length; i++){
features[i].attributes["value"] = Math.random()*60;
}
map.getLayersByName("Points")[0].redraw();
};
redraw();
}
});
很少有元素,效果很好。 但是,如果我將顯示元素的數量設置為200並使用Firefox打開腳本,則滑塊會非常慢,並且不會跟隨鼠標光標,盡管它在Chrome上運行良好。
您可以在以下jsfiddle上找到我的源代碼: http : //jsfiddle.net/jeje/5XPcc/6/
有人知道我做錯了什么嗎? 您是否認為有改進的方法?
我用forEach
方法,反序,++計數器嘗試了您的代碼,結果仍然相同,因此問題可能出在map.getLayersByName("Points")[0].redraw()
指令上。
如果在redraw
函數中for
循環添加注釋,它將使您的代碼執行速度變慢(更改滑塊值時只需重繪Points
層)。 實時重繪似乎有很多要點,而JS在FF上做得不夠快。
也許您可以進入OpenLayers庫並嘗試對其進行破解以對FF進行一些改進。 其他解決方案是將此代碼發布到OpenLayers郵件列表中,以便他們可以為您提供更好的幫助。
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