title: 【openlayer】add a feature to layer,but can not get the feature by click event,how to resolve the problem
body: <h1>Question</h1>
  <p>openlayers
  version: 6.4.3</p>
  <p>Add a feature which is created by a SVG string to map,then click the the feature on the map, but can not get the feature from the callback function. However, i make a feature with a nomarl image url, i can get the featurn by click feature on map.</p>
  <p>how can I resolve the problem</p>
  <h1>code</h1>
  <pre class="lang-js prettyprint-override"><code>import 'ol/ol.css';
  import Feature from 'ol/Feature';
  import Map from 'ol/Map';
  import Point from 'ol/geom/Point';
  import TileJSON from 'ol/source/TileJSON';
  import VectorSource from 'ol/source/Vector';
  import View from 'ol/View';
  import {Icon, Style} from 'ol/style';
  import {Tile as TileLayer, Vector as VectorLayer} from 'ol/layer';
  
  const iconFeature = new Feature({
    geometry: new Point([0, 0]),
    name: 'Null Island',
    population: 4000,
    rainfall: 500,
  });
  const src =
    `data:image/svg+xml;utf8,` +
    `&lt;svg version=&quot;1.1&quot; xmlns=&quot;http://www.w3.org/2000/svg&quot; &gt;` +
    `&lt;path d='M0,0 L0,60 L90,30 z'/&gt;` +
    &quot;&lt;/svg&gt;&quot;;
  
  const iconStyle = new Style({
    image: new Icon({
      anchor: [0.5, 46],
      anchorXUnits: 'fraction',
      anchorYUnits: 'pixels',
      src,
    }),
  });
  
  iconFeature.setStyle(iconStyle);
  
  const vectorSource = new VectorSource({
    features: [iconFeature],
  });
  
  const vectorLayer = new VectorLayer({
    source: vectorSource,
  });
  
  const rasterLayer = new TileLayer({
    source: new TileJSON({
      url: 'https://a.tiles.mapbox.com/v3/aj.1x1-degrees.json?secure=1',
      crossOrigin: '',
    }),
  });
  
  const target = document.getElementById('map');
  const map = new Map({
    layers: [rasterLayer, vectorLayer],
    target: target,
    view: new View({
      center: [0, 0],
      zoom: 3,
    }),
  });
  map.on(&quot;click&quot;, function (evt) {
    const feature = map.forEachFeatureAtPixel(evt.pixel, function (feature) {
      return feature;
    });
    // when i click the feature area,i can't get the feature
    console.log(feature) //undefined
  });
  </code></pre>
  <p><a href="https://i.stack.imgur.com/o7cow.png" rel="nofollow noreferrer">result</a></p>