急，请教openlayers的问题！！！

[tangjr]

我要做在地图上画个矩形，画完之后取得矩形的范围的功能，对openlayers了解不深不知道如何下手，请教各位大侠，谢了！

[metaboy]

看openlayer的demo，不知道现在版本是多少，我记得我用2.6的时候里面有类似的demo程序！你可以参考研究下！

[传说中的堕落]

同楼上.

[laowei206]

参见examples目录下的custom-control.html
按shift键拉框

代码如下：
function init(){
map = new OpenLayers.Map('map');
layer = new OpenLayers.Layer.WMS( "OpenLayers WMS",
"http://labs.metacarta.com/wms/vmap0", {layers: 'basic'} );

var control = new OpenLayers.Control();

OpenLayers.Util.extend(control, {
draw: function () {
// this Handler.Box will intercept the shift-mousedown
// before Control.MouseDefault gets to see it
this.box = new OpenLayers.Handler.Box( control,
{"done": this.notice},
{keyMask: OpenLayers.Handler.MOD_SHIFT});
this.box.activate();
},

notice: function (bounds) {
var ll = map.getLonLatFromPixel(new OpenLayers.Pixel(bounds.left, bounds.bottom));
var ur = map.getLonLatFromPixel(new OpenLayers.Pixel(bounds.right, bounds.top));
alert(ll.lon.toFixed(4) + ", " +
ll.lat.toFixed(4) + ", " +
ur.lon.toFixed(4) + ", " +
ur.lat.toFixed(4));
}
});

map.addLayer(layer);
map.addControl(control);
map.setCenter(new OpenLayers.LonLat(lon, lat), zoom);
}