概述：
本文讲述的是Ol3中的control的介绍和应用。
OL2和OL3 control比较：
相比较Ol2的control，OL3显得特别少，下图分别为Ol2和Ol3的control：
Ol2的control
Ol3的control
相比较Ol2，OL3保留了mouseposition，scaleline，zoom，zoomslider，而将很多东西例如draw等转移到了interaction下面，下图为Ol3的interaction：
OL3中control的常用操作：
Ol3中control的常用操作包括获取control集，添加，删除。
获取control集
var controls = map.getControls();
添加
map.addControl(ctrl);
删除
map.removeControl(ctrl);
OL3添加control示例：
下面是一个比较完成的OL3的Control的示例，
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>control</title>
<link rel="stylesheet" type="text/css" href="http://localhost/ol3/css/ol.css"/>
<style type="text/css">
body, #map {
border: 0px;
margin: 0px;
padding: 0px;
100%;
height: 100%;
font-size: 13px;
}
#location{
position: absolute;
bottom: 10px;
left: 45%;
font-weight: bold;
z-index: 99;
}
#switch{
position:absolute;
right:20pt;
top:40pt;
z-index:999;
}
#rotation{
position: absolute;
top: 10px;
left: 45%;
font-weight: bold;
z-index: 99;
}
.ol-zoomslider{
background: #d0e5f5;
20px;
}
.zoom-to-extent{
position: absolute;
top: 5pt;
left: 28pt;
}
.map-rotate{
position: absolute;
top: 5pt;
left: 45%;
}
</style>
<script type="text/javascript" src="http://localhost/ol3/build/ol.js"></script>
<script type="text/javascript" src="http://localhost/jquery/jquery-1.8.3.js"></script>
<script type="text/javascript">
function init(){
var format = 'image/png';
var bounds = [73.4510046356223, 18.1632471876417,
134.976797646506, 53.5319431522236];
var controls = new Array();
//鼠标位置
var mousePositionControl = new ol.control.MousePosition({
className: 'custom-mouse-position',
target: document.getElementById('location'),
coordinateFormat: ol.coordinate.createStringXY(5),//保留5位小数
undefinedHTML: ' '
});
controls.push(mousePositionControl);
//缩放至范围
var zoomToExtentControl = new ol.control.ZoomToExtent({
extent: bounds,
className: 'zoom-to-extent',
tipLabel:"全图"
});
controls.push(zoomToExtentControl);
//比例尺
var scaleLineControl = new ol.control.ScaleLine({});
controls.push(scaleLineControl);
//全图
var fullScreenControl = new ol.control.FullScreen({});
controls.push(fullScreenControl);
//缩放控件
var zoomSliderControl = new ol.control.ZoomSlider({});
controls.push(zoomSliderControl);
var rotate = new ol.control.Rotate({
// label:"↑",
tipLabel:"重置",
target:document.getElementById('rotation'),
autoHide:false
});
controls.push(rotate);
var untiled = new ol.layer.Image({
source: new ol.source.ImageWMS({
ratio: 1,
url: 'http://localhost:8081/geoserver/lzugis/wms',
params: {'FORMAT': format,
'VERSION': '1.1.1',
LAYERS: 'lzugis:province',
STYLES: ''
}
})
});
var projection = new ol.proj.Projection({
code: 'EPSG:4326',
units: 'degrees'
});
var map = new ol.Map({
controls: ol.control.defaults({
attribution: false
}).extend(controls),
interactions: ol.interaction.defaults().extend([
new ol.interaction.DragRotateAndZoom()
]),
target: 'map',
layers: [
untiled
],
view: new ol.View({
projection: projection,
rotation:-45
})
});
map.getView().fitExtent(bounds, map.getSize());
$("#setRotate").on("click",function(){
var angle = $("#rotate").val();
map.getView().setRotation(angle);
});
}
</script>
</head>
<body onLoad="init()">
<div class="layer-change-switch" id="switch">
<div id="slider">
<input id="rotate" type="text" value="-45" maxlength="10" style=" 50px;" /><button id="setRotate">旋转</button>
</div>
</div>
<div id="map">
<div id="rotation"></div>
<div id="location"></div>
</div>
</body>
</html>
上述代码效果如下：
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