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rotationopenlayersmarker

Rotate marker with animation in Openlayers


I have this code:

this.posFeature = new ol.Feature({
    geometry: new ol.geom.Point(ol.proj.fromLonLat([-5.7,43.5])),
    name: 'pos'
});
var posStyle = new ol.style.Style({
    image: new ol.style.Icon({
        anchor: [10, 10],
        anchorXUnits: 'pixels',
        anchorYUnits: 'pixels',
        src: 'car.svg'
    })
});
this.posFeature.setStyle(posStyle);
this.markerPosSource = new ol.source.Vector({features: [this.posFeature]});
this.layerPos = new ol.layer.Vector({source: this.markerPosSource});
map.addLayer(this.layerPos);

I would like to rotate the icon with an animation (in its rotation). Is it possible? If not, how to rotate without animation?

Thanks in advance!


Solution

  • To smoothly animate a rotation calculate the required rotation based on elapsed time each time the map rendered, e.g. for a complete rotation every 10 seconds:

    <!DOCTYPE html>
    <html>
      <head>
        <title>Icon Symbolizer</title>
        <link rel="stylesheet" href="https://openlayers.org/en/v6.4.3/css/ol.css" type="text/css">
        <script src="https://openlayers.org/en/v6.4.3/build/ol.js"></script>
        <style>
          html, body, .map {
            margin: 0;
            padding: 0;
            width: 100%;
            height: 100%;
          }
        </style>
      </head>
      <body>
        <div id="map" class="map"></div>
        <script>
          var iconFeature = new ol.Feature({
            geometry: new ol.geom.Point([0, 0]),
            name: 'Null Island',
            population: 4000,
            rainfall: 500
          });
    
          var iconStyle = new ol.style.Style({
            image: new ol.style.Icon({
              anchor: [0.5, 1],
              src: 'https://openlayers.org/en/v6.4.3/examples/data/icon.png'
            })
          });
    
          iconFeature.setStyle(iconStyle);
    
          var vectorSource = new ol.source.Vector({
            features: [iconFeature]
          });
    
          var vectorLayer = new ol.layer.Vector({
            source: vectorSource
          });
    
          var map = new ol.Map({
            layers: [vectorLayer],
            target: document.getElementById('map'),
            view: new ol.View({
              center: [0, 0],
              zoom: 3
            })
          });
    
          var startTime = new Date().getTime();
    
          map.on('rendercomplete', function(e) {
            var elapsedTime = e.frameState.time - startTime;
            var rotation = elapsedTime / 10000 * Math.PI;
            iconStyle.getImage().setRotation(rotation);
            iconFeature.changed();
          });
        </script>
      </body>
    </html>