Openlayers:添加一个纯色图层作为覆盖

<script src="https://openlayers.org/en/v6.5.0/build/ol.js"></script>

<div id="map" style="width: 100%; height: 400px;"></div>

var map = new ol.Map({
  target: 'map',
  view: new ol.View({
    center: ol.proj.fromLonLat([0, 0]),
    zoom: 2
  })
});

var colorLayer = new ol.layer.Tile({
  source: new ol.source.TileWMS({
    url: 'https://your-wms-server.com',
    params: {
      'LAYERS': 'color-layer',
      'TILED': true
    },
    serverType: 'geoserver'
  })
});

map.addLayer(colorLayer);

colorLayer.setStyle(new ol.style.Style({
  fill: new ol.style.Fill({
    color: 'rgba(255, 0, 0, 0.5)' // 设置纯色图层的颜色
  })
}));