XYZ Retina Tiles

Example of Retina / HiDPI mercator tiles (512x512px) available as XYZ.

The ol.source.XYZ must contain tilePixelRatio parameter. The tiles were prepared from a GeoTIFF file with MapTiler.

<!DOCTYPE html>
<html>
  <head>
    <title>XYZ Retina Tiles</title>
    <link rel="stylesheet" href="https://openlayers.org/en/v4.6.4/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>
    <script src="https://openlayers.org/en/v4.6.4/build/ol.js"></script>
  </head>
  <body>
    <div id="map" class="map"></div>
    <script>
      var mapMinZoom = 1;
      var mapMaxZoom = 15;
      var mapExtent = [-112.261791, 35.983744, -112.113981, 36.132062];

      var map = new ol.Map({
        target: 'map',
        layers: [
          new ol.layer.Tile({
            source: new ol.source.OSM()
          }),
          new ol.layer.Tile({
            extent: ol.proj.transformExtent(mapExtent, 'EPSG:4326', 'EPSG:3857'),
            source: new ol.source.XYZ({
              attributions: 'Tiles © USGS, rendered with ' +
                  '<a href="http://www.maptiler.com/">MapTiler</a>',
              url: 'https://tileserver.maptiler.com/grandcanyon@2x/{z}/{x}/{y}.png',
              tilePixelRatio: 2, // THIS IS IMPORTANT
              minZoom: mapMinZoom,
              maxZoom: mapMaxZoom
            })
          })
        ],
        view: new ol.View({
          projection: 'EPSG:3857',
          center: ol.proj.transform([-112.18688965, 36.057944835],
              'EPSG:4326', 'EPSG:3857'),
          zoom: 12
        })
      });
    </script>
  </body>
</html>