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Freehand Drawing

Example using the ol/interaction/Draw interaction in freehand mode.

This example demonstrates the ol/interaction/Draw in freehand mode. During freehand drawing, points are added while dragging. Set freehand: true to enable freehand mode. Note that freehand mode can be conditionally enabled by using the freehandCondition option. For example to toggle freehand mode with the Shift key, use freehandCondition: shiftKeyOnly.

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index.html<!DOCTYPE html>
<html lang="en">
  <head>
    <title>Freehand Drawing</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=requestAnimationFrame,Element.prototype.classList,URL"></script>
    <style>
      .map {
        width: 100%;
        height:400px;
      }
    </style>
  </head>
  <body>
    <div id="map" class="map"></div>
    <form class="form-inline">
      <label>Geometry type &nbsp;</label>
      <select id="type">
        <option value="LineString">LineString</option>
        <option value="Polygon">Polygon</option>
        <option value="Circle">Circle</option>
        <option value="None">None</option>
      </select>
    </form>
    <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 Draw from 'ol/interaction/Draw';
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 source = new VectorSource({wrapX: false});

var vector = new VectorLayer({
  source: source
});

var map = new Map({
  layers: [raster, vector],
  target: 'map',
  view: new View({
    center: [-11000000, 4600000],
    zoom: 4
  })
});

var typeSelect = document.getElementById('type');

var draw; // global so we can remove it later
function addInteraction() {
  var value = typeSelect.value;
  if (value !== 'None') {
    draw = new Draw({
      source: source,
      type: typeSelect.value,
      freehand: true
    });
    map.addInteraction(draw);
  }
}


/**
 * Handle change event.
 */
typeSelect.onchange = function() {
  map.removeInteraction(draw);
  addInteraction();
};

addInteraction();
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package.json{
  "name": "draw-freehand",
  "dependencies": {
    "ol": "6.1.1"
  },
  "devDependencies": {
    "parcel": "1.11.0"
  },
  "scripts": {
    "start": "parcel index.html",
    "build": "parcel build --experimental-scope-hoisting --public-url . index.html"
  }
}