Export PDF example

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Export PDF example

Example of exporting a map as a PDF.

Example of exporting a map as a PDF using the jsPDF library.

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index.html<!DOCTYPE html>
<html lang="en">
  <head>
    <title>Export PDF example</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>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/jspdf/1.5.3/jspdf.min.js"></script>
    <style>
      .map {
        width: 100%;
        height:400px;
      }
      .map {
        max-width: 566px;
      }
    </style>
  </head>
  <body>
    <div class="row-fluid">
      <div class="span12">
        <div id="map" class="map"></div>
      </div>
    </div>
    <form class="form">
      <label>Page size </label>
      <select id="format">
        <option value="a0">A0 (slow)</option>
        <option value="a1">A1</option>
        <option value="a2">A2</option>
        <option value="a3">A3</option>
        <option value="a4" selected>A4</option>
        <option value="a5">A5 (fast)</option>
      </select>
      <label>Resolution </label>
      <select id="resolution">
        <option value="72">72 dpi (fast)</option>
        <option value="150">150 dpi</option>
        <option value="300">300 dpi (slow)</option>
      </select>
    </form>
    <button id="export-pdf">Export PDF</button>
    <script src="index.js"></script>
  </body>
</html>

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index.jsimport 'ol/ol.css';
import Map from 'ol/Map';
import View from 'ol/View';
import WKT from 'ol/format/WKT';
import {Tile as TileLayer, Vector as VectorLayer} from 'ol/layer';
import {OSM, Vector as VectorSource} from 'ol/source';

var raster = new TileLayer({
  source: new OSM()
});

var format = new WKT();
var feature = format.readFeature(
  'POLYGON((10.689697265625 -25.0927734375, 34.595947265625 ' +
        '-20.1708984375, 38.814697265625 -35.6396484375, 13.502197265625 ' +
        '-39.1552734375, 10.689697265625 -25.0927734375))');
feature.getGeometry().transform('EPSG:4326', 'EPSG:3857');

var vector = new VectorLayer({
  source: new VectorSource({
    features: [feature]
  }),
  opacity: 0.5
});


var map = new Map({
  layers: [raster, vector],
  target: 'map',
  view: new View({
    center: [0, 0],
    zoom: 2
  })
});


var dims = {
  a0: [1189, 841],
  a1: [841, 594],
  a2: [594, 420],
  a3: [420, 297],
  a4: [297, 210],
  a5: [210, 148]
};


var exportButton = document.getElementById('export-pdf');

exportButton.addEventListener('click', function() {

  exportButton.disabled = true;
  document.body.style.cursor = 'progress';

  var format = document.getElementById('format').value;
  var resolution = document.getElementById('resolution').value;
  var dim = dims[format];
  var width = Math.round(dim[0] * resolution / 25.4);
  var height = Math.round(dim[1] * resolution / 25.4);
  var size = map.getSize();
  var viewResolution = map.getView().getResolution();

  map.once('rendercomplete', function() {
    var mapCanvas = document.createElement('canvas');
    mapCanvas.width = width;
    mapCanvas.height = height;
    var mapContext = mapCanvas.getContext('2d');
    Array.prototype.forEach.call(document.querySelectorAll('.ol-layer canvas'), function(canvas) {
      if (canvas.width > 0) {
        var opacity = canvas.parentNode.style.opacity;
        mapContext.globalAlpha = opacity === '' ? 1 : Number(opacity);
        var transform = canvas.style.transform;
        // Get the transform parameters from the style's transform matrix
        var matrix = transform.match(/^matrix\(([^\(]*)\)$/)[1].split(',').map(Number);
        // Apply the transform to the export map context
        CanvasRenderingContext2D.prototype.setTransform.apply(mapContext, matrix);
        mapContext.drawImage(canvas, 0, 0);
      }
    });
    var pdf = new jsPDF('landscape', undefined, format);
    pdf.addImage(mapCanvas.toDataURL('image/jpeg'), 'JPEG', 0, 0, dim[0], dim[1]);
    pdf.save('map.pdf');
    // Reset original map size
    map.setSize(size);
    map.getView().setResolution(viewResolution);
    exportButton.disabled = false;
    document.body.style.cursor = 'auto';
  });

  // Set print size
  var printSize = [width, height];
  map.setSize(printSize);
  var scaling = Math.min(width / size[0], height / size[1]);
  map.getView().setResolution(viewResolution / scaling);

}, false);

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package.json{
  "name": "export-pdf",
  "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"
  }
}