原文链接及内容

原文链接：https://openlayers.org/en/latest/examples/custom-controls.html

运行界面

这个例子创建了一个“向北旋转”按钮(控件)。

main.js代码如下：

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import Map from 'ol/Map.js';
import OSM from 'ol/source/OSM.js';
import TileLayer from 'ol/layer/Tile.js';
import View from 'ol/View.js';
import {Control, defaults as defaultControls} from 'ol/control.js';

//
// Define rotate to north control.
//

class RotateNorthControl extends Control {
  /**
   * @param {Object} [opt_options] Control options.
   */
  constructor(opt_options) {
    const options = opt_options || {};

    const button = document.createElement('button');
    button.innerHTML = 'N';

    const element = document.createElement('div');
    element.className = 'rotate-north ol-unselectable ol-control';
    element.appendChild(button);

    super({
      element: element,
      target: options.target,
    });

    button.addEventListener('click', this.handleRotateNorth.bind(this), false);
  }

  handleRotateNorth() {
    this.getMap().getView().setRotation(0);
  }
}

//
// Create map, giving it a rotate to north control.
//

const map = new Map({
  controls: defaultControls().extend([new RotateNorthControl()]),
  layers: [
    new TileLayer({
      source: new OSM(),
    }),
  ],
  target: 'map',
  view: new View({
    center: [0, 0],
    zoom: 3,
    rotation: 1,
  }),
});

界面布局文件index.html代码如下：

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<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <title>Custom Controls</title>
    <link rel="stylesheet" href="node_modules/ol/ol.css">
    <style>
      .map {
        width: 100%;
        height: 400px;
      }
      .rotate-north {
        top: 65px;
        left: .5em;
      }
      .ol-touch .rotate-north {
        top: 80px;
      }
    </style>
  </head>
  <body>
    <div id="map" class="map"></div>
    <!-- Pointer events polyfill for old browsers, see https://caniuse.com/#feat=pointer -->
    <script src="https://cdn.jsdelivr.net/npm/elm-pep@1.0.6/dist/elm-pep.js"></script>
    <script type="module" src="main.js"></script>
  </body>
</html>