OpenLayers修改功能样式而不覆盖交互样式

Question

有没有办法修改单个功能的样式而不修改选择交互的默认样式？

这是一段简单的代码，显示了我的问题和一个jsfiddle

最小的HTML：

<input type="button" id="switcher" value="Change style"></input>
<div id="map" class="map"></div>

还有一个简单的脚本：

let vectorLayer = new ol.layer.Vector({
  source: new ol.source.Vector({wrapX: false})
});

let map = new ol.Map({
  target: 'map',
  layers: [
    new ol.layer.Tile({
      source: new ol.source.OSM({wrapX: false})
    }),
    vectorLayer,
  ],
  view: new ol.View({
    center: ol.proj.transform([9, 44.65], 'EPSG:4326', 'EPSG:3857'),
    zoom: 8
  })
});

let source = vectorLayer.getSource();

let draw = new ol.interaction.Draw({
  source: source,
  type: 'Polygon'
});

let selectOnHover = new ol.interaction.Select({
    source: source,
    condition: ol.events.condition.pointerMove
});

map.addInteraction(draw);
map.addInteraction(selectOnHover);

let fill = new ol.style.Fill({
  color: 'rgba(255,0,255,0.4)'
});
let stroke = new ol.style.Stroke({
  color: '#00FF00',
  width: 5
});
let customStyle = new ol.style.Style({
  image: new ol.style.Circle({
    fill: fill,
    stroke: stroke,
    radius: 5
  }),
  fill: fill,
  stroke: stroke
});

document.getElementById('switcher').onclick = function(event) {
  let features = source.getFeatures();
  if(features.length>0)
    features[0].setStyle(customStyle);
}

正如您在jsfiddle上测试所看到的，单击该按钮将正确地更改第一个绘制特征的样式，但似乎也会覆盖悬停时的默认样式（这里只是与条件的选择交互）。

如何在更改我的功能样式时保持悬停的默认样式？

Answer 1

要素上的样式将覆盖所有样式函数（以及交互的默认样式等）。 但是，您可以为要素提供customStyle属性，并仅在图层样式函数中使用它而不是默认样式，而交互将继续使用默认值进行交互。

let defaultFill = new ol.style.Fill({
  color: 'rgba(255,255,255,0.4)'
});
var defaultStroke = new ol.style.Stroke({
  color: '#3399CC',
  width: 1.25
});
var defaultStyles = [
  new ol.style.Style({
    image: new ol.style.Circle({
      fill: defaultFill,
      stroke: defaultStroke,
      radius: 5
    }),
    fill: defaultFill,
    stroke: defaultStroke
  })
];

let vectorLayer = new ol.layer.Vector({
  source: new ol.source.Vector({wrapX: false}),
  style: function(feature) { 
    var customStyle = feature.get('customStyle');
    return customStyle || defaultStyles;
  }
});


...
...

document.getElementById('switcher').onclick = function(event) {
  let features = source.getFeatures();
  if(features.length>0)
    features[0].set('customStyle', customStyle);
}