Icon 位置修改

本示例演示使用 Modify 交互编辑 icon 对象.

地图上的 icon 图标（实际是feature）可以通过拖拽来改变它的位置。

Modify 交互可以设置 hitDetection 参数选项。设置了这个参数，拖动的时候，不再是选中点（by the pixelTolerance），而是选中图标。

main.js

import Feature from 'ol/Feature.js';
import Map from 'ol/Map.js';
import Point from 'ol/geom/Point.js';
import TileJSON from 'ol/source/TileJSON.js';
import VectorSource from 'ol/source/Vector.js';
import View from 'ol/View.js';
import {Icon, Style} from 'ol/style.js';
import {Modify} from 'ol/interaction.js';
import {Tile as TileLayer, Vector as VectorLayer} from 'ol/layer.js';

const iconFeature = new Feature({
  geometry: new Point([0, 0]),
  name: 'Null Island',
  population: 4000,
  rainfall: 500,
});

const iconStyle = new Style({
  image: new Icon({
    anchor: [0.5, 46],
    anchorXUnits: 'fraction',
    anchorYUnits: 'pixels',
    src: 'data/icon.png',
  }),
});

iconFeature.setStyle(iconStyle);

const vectorSource = new VectorSource({
  features: [iconFeature],
});

const vectorLayer = new VectorLayer({
  source: vectorSource,
});

const rasterLayer = new TileLayer({
  source: new TileJSON({
    url: 'https://a.tiles.mapbox.com/v3/aj.1x1-degrees.json?secure=1',
    crossOrigin: '',
  }),
});

const target = document.getElementById('map');
const map = new Map({
  layers: [rasterLayer, vectorLayer],
  target: target,
  view: new View({
    center: [0, 0],
    zoom: 3,
  }),
});

const modify = new Modify({
  hitDetection: vectorLayer,
  source: vectorSource,
});
modify.on(['modifystart', 'modifyend'], function (evt) {
  target.style.cursor = evt.type === 'modifystart' ? 'grabbing' : 'pointer';
});
const overlaySource = modify.getOverlay().getSource();
overlaySource.on(['addfeature', 'removefeature'], function (evt) {
  target.style.cursor = evt.type === 'addfeature' ? 'pointer' : '';
});

map.addInteraction(modify);

index.html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <title>Icon modification</title>
    <link rel="stylesheet" href="node_modules/ol/ol.css">
    <style>
      .map {
        width: 100%;
        height: 400px;
      }
    </style>
  </head>
  <body>
    <div id="map" class="map"></div>
    <!-- Pointer events polyfill for old browsers, see https://caniuse.com/#feat=pointer -->
    <script src="./resources/elm-pep.js"></script>
    <script type="module" src="main.js"></script>
  </body>
</html>

package.json

{
  "name": "modify-icon",
  "dependencies": {
    "ol": "7.3.0"
  },
  "devDependencies": {
    "vite": "^3.2.3"
  },
  "scripts": {
    "start": "vite",
    "build": "vite build"
  }
}