Openlayers 3添加带图标和文字的可移动标记

Question

在OL3中,我成功制作了一个有可移动标记的地图:

var mapVectorSource = new ol.source.Vector({
    features: []
});
var mapVectorLayer = new ol.layer.Vector({
    source: mapVectorSource
});
map.addLayer(mapVectorLayer);

function makeMovable(feature) {
    var modify = new ol.interaction.Modify({
        features: new ol.Collection([feature])
    });

    feature.on('change',function() {
        console.log('Feature Moved To:' + this.getGeometry().getCoordinates());
    }, feature);
    return modify;
}

function createMarker(location, style){
    var iconFeature = new ol.Feature({
        geometry: new ol.geom.Point(location)
    });
    iconFeature.setStyle(style);

    return iconFeature
}

iconStyle = new ol.style.Style({
    image: new ol.style.Icon(/** @type {olx.style.IconOptions} */ ({
        anchor: [0.5, 1],
        anchorXUnits: 'fraction',
        anchorYUnits: 'fraction',
        src: '/static/img/marker-icon.png',
    }))
});
var marker = createMarker(ol.proj.transform([38, 50], 'EPSG:4326', 'EPSG:3857'), iconStyle);
mapVectorSource.addFeature(marker);
var modifyInteraction = makeMovable(marker);
map.addInteraction(modifyInteraction);

但我想添加> 10个标记,所以我需要用数字或文字标记它们.有没有办法在叠加层中添加文字？如果我检查iconStyle,我看到它有一个getText()功能,但该功能总是只返回undefined,没有附带的setText()功能.像这样定义它似乎很自然:

iconStyle = new ol.style.Style({
    image: new ol.style.Icon(/** @type {olx.style.IconOptions} */ ({
        anchor: [0.5, 1],
        anchorXUnits: 'fraction',
        anchorYUnits: 'fraction',
        src: '/static/img/marker-icon.png',
    })),
    text: "Hello, Marker"    // <- operative line
});

但似乎不允许这样做.另一个自然选择可能是将html元素附加到样式,以便我们可以渲染任何我们想要的东西,但似乎没有办法做到这一点.

那么,如何创建具有文本标签的标记？

Answer 1

如本例所示,解决方案是使用样式列表而不是单个样式.

在这种情况下,它非常简单:

iconStyle = [
    new ol.style.Style({
        image: new ol.style.Icon(/** @type {olx.style.IconOptions} */ ({
            anchor: [0.5, 1],
            anchorXUnits: 'fraction',
            anchorYUnits: 'fraction',
            src: '/static/img/marker-icon.png',
        }))
    }),
    new ol.style.Style({
        text: new ol.style.Text({
            text: "Wow such label",
            offsetY: -25,
            fill: new ol.style.Fill({
                color: '#fff'
            })
        })
    })
];