javascript - OpenLayers:单击关闭(但不完全)矢量以获取矢量特征

Question

我有一个 Open Street Map 和一些出现在道路上的矢量(线)。当我点击矢量时，我可以获得该矢量的特征，但是我只能通过准确点击矢量的像素来实现。有没有一种方法可以让我点击“靠近”矢量(可能偏离几个像素)来获取信息，这样我就不必那么精确了？

代码:

这是我目前在点击矢量时用来获取特征的方法:

var displayFeatureInfo  = function (pixel, coordinate) {
            var features = [];
            map.forEachFeatureAtPixel(pixel, function (feature, layer) {
                features.push(feature); // Pushes each feature found into the array
            });

            if (features.length > 0) {   // If there are one or more features
                $("#popup").html('<object data=' + "http://URLToLoadDataFrom '/>'); // Load the data using jQuery
                popup.setPositioning('top-left');
                popup.setPosition(coordinate);
                container.style.display = 'block';
            } else {
                container.style.display = 'none';
            }                          

        };

        map.on('click', function (evt) {
            var coordinate = evt.coordinate;
            displayFeatureInfo(evt.pixel, coordinate);    
        });

提前致谢。

Answer 1

您可以根据提供的像素构建一个范围，并使用该范围而不是单个点作为特征选择的基础。我想，这意味着您必须使用 vector.getSource().forEachFeatureIntersectingExtent 方法而不是 map.forEachFeatureAtPixel。

检查这个(fiddle here):

var displayFeatureInfo  = function (pixel, coordinate) {
            var features = [];
            //this is the offset in pixels. Adjust it to fit your needs
            var pixelOffSet = 5; 
            var pixelWithOffsetMin = [pixel[0]-pixelOffSet,pixel[1]+pixelOffSet];
            var pixelWithOffsetMax = [pixel[0]+pixelOffSet,pixel[1]-pixelOffSet];
            var XYMin =map.getCoordinateFromPixel(pixelWithOffsetMin)
            var XYMax =map.getCoordinateFromPixel(pixelWithOffsetMax)
            var extent = XYMax.concat(XYMin);
            var extentFeat= new ol.Feature(new ol.geom.Polygon([[
            [extent[0],extent[1]],
            [extent[0],extent[3]],
            [extent[2],extent[3]],
            [extent[2],extent[1]],
            [extent[0],extent[1]]
            ]]));   

            vector.getSource().forEachFeatureIntersectingExtent(extentFeat.getGeometry().getExtent(), 
            function (feature) {
                features.push(feature); // Pushes each feature found into the array
            });

            if (features.length > 0) {   // If there are one or more features
                console.log("features found on offset clicked",features)
               // container.style.display = 'block';
            } else {
              console.log("no features on offset click")
            }                          

        };

        map.on('click', function (evt) {
            var coordinate = evt.coordinate;
            displayFeatureInfo(evt.pixel, coordinate);    
        });