Export PDF example

main.js

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

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

const format = new WKT();
const 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');

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

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

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

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

exportButton.addEventListener(
  'click',
  function () {
    exportButton.disabled = true;
    document.body.style.cursor = 'progress';

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

    map.once('rendercomplete', function () {
      const mapCanvas = document.createElement('canvas');
      mapCanvas.width = width;
      mapCanvas.height = height;
      const mapContext = mapCanvas.getContext('2d');
      Array.prototype.forEach.call(
        document.querySelectorAll('.ol-layer canvas'),
        function (canvas) {
          if (canvas.width > 0) {
            const opacity = canvas.parentNode.style.opacity;
            mapContext.globalAlpha = opacity === '' ? 1 : Number(opacity);
            const transform = canvas.style.transform;
            // Get the transform parameters from the style's transform matrix
            const 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);
          }
        },
      );
      mapContext.globalAlpha = 1;
      mapContext.setTransform(1, 0, 0, 1, 0, 0);
      const pdf = new jspdf.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
    const printSize = [width, height];
    map.setSize(printSize);
    const scaling = Math.min(width / size[0], height / size[1]);
    map.getView().setResolution(viewResolution / scaling);
  },
  false,
);

index.html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <title>Export PDF example</title>
    <link rel="stylesheet" href="node_modules/ol/ol.css">
    <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 for="format">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 for="resolution">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="https://cdnjs.cloudflare.com/ajax/libs/jspdf/2.3.1/jspdf.umd.min.js"></script>
    <script type="module" src="main.js"></script>
  </body>
</html>

Export PDF example

main.js

index.html

package.json