Zoomify

Edit

Zoomify

Example of a Zoomify source.

Zoomify is a format for deep-zooming into high resolution images. This example shows how to use the Zoomify source with a pixel projection. Internet Imaging Protocol (IIP) with JTL extension is also handled.

Copy

index.html<!DOCTYPE html>
<html lang="en">
  <head>
    <title>Zoomify</title>
    <!-- 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=fetch,requestAnimationFrame,Element.prototype.classList,URL"></script>
    <style>
      .map {
        width: 100%;
        height:400px;
      }
    </style>
  </head>
  <body>
    <div id="map" class="map"></div>
    <div class="controls">
      <select id="zoomifyProtocol">
        <option value="zoomify">Zoomify</option>
        <option value="zoomifyretina">Zoomify Retina</option>
      </select>
    </div>
    <script src="index.js"></script>
  </body>
</html>

Copy

index.jsimport 'ol/ol.css';
import Map from 'ol/Map';
import View from 'ol/View';
import TileLayer from 'ol/layer/Tile';
import Zoomify from 'ol/source/Zoomify';

var imgWidth = 4000;
var imgHeight = 3000;

var zoomifyUrl = 'https://ol-zoomify.surge.sh/zoomify/';

var source = new Zoomify({
  url: zoomifyUrl,
  size: [imgWidth, imgHeight],
  crossOrigin: 'anonymous',
  zDirection: -1 // Ensure we get a tile with the screen resolution or higher
});
var extent = source.getTileGrid().getExtent();

var retinaPixelRatio = 2;
var retinaSource = new Zoomify({
  url: zoomifyUrl,
  size: [imgWidth, imgHeight],
  crossOrigin: 'anonymous',
  zDirection: -1, // Ensure we get a tile with the screen resolution or higher
  tilePixelRatio: retinaPixelRatio, // Display retina tiles
  tileSize: 256 / retinaPixelRatio // from a higher zoom level
});

var layer = new TileLayer({
  source: source
});

var map = new Map({
  layers: [layer],
  target: 'map',
  view: new View({
    // adjust zoom levels to those provided by the source
    resolutions: layer.getSource().getTileGrid().getResolutions(),
    // constrain the center: center cannot be set outside this extent
    extent: extent,
    constrainOnlyCenter: true
  })
});
map.getView().fit(extent);

var control = document.getElementById('zoomifyProtocol');
control.addEventListener('change', function(event) {
  var value = event.currentTarget.value;
  if (value === 'zoomify') {
    layer.setSource(source);
  } else if (value === 'zoomifyretina') {
    layer.setSource(retinaSource);
  }
});

Copy

package.json{
  "name": "zoomify",
  "dependencies": {
    "ol": "6.3.1"
  },
  "devDependencies": {
    "parcel": "1.11.0"
  },
  "scripts": {
    "start": "parcel index.html",
    "build": "parcel build --experimental-scope-hoisting --public-url . index.html"
  }
}