Example on how to create permalinks.
In this example the HTML 5 History API is used to update the browser URL with the current zoom-level, center and rotation when the map is moved. Note that the History API is not supported in all browsers, one might consider to use a a polyfill.
import 'ol/ol.css';
import Map from 'ol/Map';
import OSM from 'ol/source/OSM';
import TileLayer from 'ol/layer/Tile';
import View from 'ol/View';
// default zoom, center and rotation
var zoom = 2;
var center = [0, 0];
var rotation = 0;
if (window.location.hash !== '') {
// try to restore center, zoom-level and rotation from the URL
var hash = window.location.hash.replace('#map=', '');
var parts = hash.split('/');
if (parts.length === 4) {
zoom = parseInt(parts[0], 10);
center = [parseFloat(parts[1]), parseFloat(parts[2])];
rotation = parseFloat(parts[3]);
}
}
var map = new Map({
layers: [
new TileLayer({
source: new OSM(),
}) ],
target: 'map',
view: new View({
center: center,
zoom: zoom,
rotation: rotation,
}),
});
var shouldUpdate = true;
var view = map.getView();
var updatePermalink = function () {
if (!shouldUpdate) {
// do not update the URL when the view was changed in the 'popstate' handler
shouldUpdate = true;
return;
}
var center = view.getCenter();
var hash =
'#map=' +
view.getZoom() +
'/' +
Math.round(center[0] * 100) / 100 +
'/' +
Math.round(center[1] * 100) / 100 +
'/' +
view.getRotation();
var state = {
zoom: view.getZoom(),
center: view.getCenter(),
rotation: view.getRotation(),
};
window.history.pushState(state, 'map', hash);
};
map.on('moveend', updatePermalink);
// restore the view state when navigating through the history, see
// https://developer.mozilla.org/en-US/docs/Web/API/WindowEventHandlers/onpopstate
window.addEventListener('popstate', function (event) {
if (event.state === null) {
return;
}
map.getView().setCenter(event.state.center);
map.getView().setZoom(event.state.zoom);
map.getView().setRotation(event.state.rotation);
shouldUpdate = false;
});
<!DOCTYPE html>
<html lang="en">
<head>
<title>Permalink</title>
<!-- Pointer events polyfill for old browsers, see https://caniuse.com/#feat=pointer -->
<script src="https://unpkg.com/elm-pep"></script>
<style>
.map {
width: 100%;
height:400px;
}
</style>
</head>
<body>
<div id="map" class="map"></div>
<script src="main.js"></script>
</body>
</html>
{
"name": "permalink",
"dependencies": {
"ol": "6.4.3"
},
"devDependencies": {
"parcel": "1.11.0"
},
"scripts": {
"start": "parcel index.html",
"build": "parcel build --experimental-scope-hoisting --public-url . index.html"
}
}