Pinch Zoom

Restrict pinch zooming to integer zoom levels.

By default, the ol/interaction/PinchZoom can leave the map at fractional zoom levels. If instead you want to constrain pinch zooming to integer zoom levels, set constrainResolution: true when constructing the interaction.

<!DOCTYPE html>
<html>
  <head>
    <title>Pinch Zoom</title>
    <link rel="stylesheet" href="https://openlayers.org/en/v5.3.0/css/ol.css" type="text/css">
    <!-- The line below is only needed for old environments like Internet Explorer and Android 4.x -->
    <script src="https://cdn.polyfill.io/v2/polyfill.min.js?features=requestAnimationFrame,Element.prototype.classList,URL"></script>

  </head>
  <body>
    <div id="map" class="map"></div>
    <script>
      import Map from 'ol/Map.js';
      import View from 'ol/View.js';
      import {defaults as defaultInteractions, PinchZoom} from 'ol/interaction.js';
      import TileLayer from 'ol/layer/Tile.js';
      import OSM from 'ol/source/OSM.js';


      var map = new Map({
        interactions: defaultInteractions({pinchZoom: false}).extend([
          new PinchZoom({
            constrainResolution: true // force zooming to a integer zoom
          })
        ]),
        layers: [
          new TileLayer({
            source: new OSM()
          })
        ],
        target: 'map',
        view: new View({
          center: [0, 0],
          zoom: 2
        })
      });
    </script>
  </body>
</html>