Source: control/difference.js

  1. import OL3Parser from 'jsts/org/locationtech/jts/io/OL3Parser';
  2. import { OverlayOp } from 'jsts/org/locationtech/jts/operation/overlay';
  3. import LinearRing from 'ol/geom/LinearRing';
  4. import {
  5.   Point,
  6.   LineString,
  7.   Polygon,
  8.   MultiPoint,
  9.   MultiLineString,
  10.   MultiPolygon,
  11. } from 'ol/geom';
  12. import TopologyControl from './topology';
  13. import diffSVG from '../../img/difference.svg';
  15. /**
  16.  * Control for creating a difference of geometries.
  17.  * @extends {ole.Control}
  18.  * @alias ole.Difference
  19.  */
  20. class Difference extends TopologyControl {
  21.   /**
  22.    * @inheritdoc
  23.    * @param {Object} [options] Control options.
  24.    * @param {number} [options.hitTolerance] Select tolerance in pixels
  25.    *   (default is 10)
  26.    */
  27.   constructor(options) {
  28.     super({
  29.       title: 'Difference',
  30.       className: 'ole-control-difference',
  31.       image: diffSVG,
  32.       ...options,
  33.     });
  34.   }
  36.   /**
  37.    * Apply a difference operation for given features.
  38.    * @param {Array.<ol.Feature>} features Features.
  39.    */
  40.   applyTopologyOperation(features) {
  41.     super.applyTopologyOperation(features);
  43.     if (features.length < 2) {
  44.       return;
  45.     }
  47.     const parser = new OL3Parser();
  48.     parser.inject(
  49.       Point,
  50.       LineString,
  51.       LinearRing,
  52.       Polygon,
  53.       MultiPoint,
  54.       MultiLineString,
  55.       MultiPolygon,
  56.     );
  58.     for (let i = 1; i < features.length; i += 1) {
  59.       const geom = parser.read(features[0].getGeometry());
  60.       const otherGeom = parser.read(features[i].getGeometry());
  61.       const diffGeom = OverlayOp.difference(geom, otherGeom);
  62.       features[0].setGeometry(parser.write(diffGeom));
  63.       features[i].setGeometry(null);
  64.     }
  65.   }
  66. }
  68. export default Difference;