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动画展示数据

发布于 2022-11-30 23:36:03 字数 3744 浏览 0 评论 0 收藏 0

本示例演示动画展示数据.

main.js

import 'ol/ol.css';
import Map from 'ol/Map';
import OSM from 'ol/source/OSM';
import TileLayer from 'ol/layer/Tile';
import View from 'ol/View';
import {Circle as CircleStyle, Fill, Stroke, Style} from 'ol/style';
import {MultiPoint, Point} from 'ol/geom';
import {getVectorContext} from 'ol/render';

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

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

const imageStyle = new Style({
  image: new CircleStyle({
    radius: 5,
    fill: new Fill({color: 'yellow'}),
    stroke: new Stroke({color: 'red', width: 1}),
  }),
});

const headInnerImageStyle = new Style({
  image: new CircleStyle({
    radius: 2,
    fill: new Fill({color: 'blue'}),
  }),
});

const headOuterImageStyle = new Style({
  image: new CircleStyle({
    radius: 5,
    fill: new Fill({color: 'black'}),
  }),
});

const n = 200;
const omegaTheta = 30000; // Rotation period in ms
const R = 7e6;
const r = 2e6;
const p = 2e6;
tileLayer.on('postrender', function (event) {
  const vectorContext = getVectorContext(event);
  const frameState = event.frameState;
  const theta = (2 * Math.PI * frameState.time) / omegaTheta;
  const coordinates = [];
  let i;
  for (i = 0; i < n; ++i) {
    const t = theta + (2 * Math.PI * i) / n;
    const x = (R + r) * Math.cos(t) + p * Math.cos(((R + r) * t) / r);
    const y = (R + r) * Math.sin(t) + p * Math.sin(((R + r) * t) / r);
    coordinates.push([x, y]);
  }
  vectorContext.setStyle(imageStyle);
  vectorContext.drawGeometry(new MultiPoint(coordinates));

  const headPoint = new Point(coordinates[coordinates.length - 1]);

  vectorContext.setStyle(headOuterImageStyle);
  vectorContext.drawGeometry(headPoint);

  vectorContext.setStyle(headInnerImageStyle);
  vectorContext.drawGeometry(headPoint);

  map.render();
});
map.render();

index.html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <title>Dynamic Data</title>
    <!-- Pointer events polyfill for old browsers, see https://caniuse.com/#feat=pointer -->
    <script src="https://unpkg.com/elm-pep"></script>
    <!-- The line below is only needed for old environments like Internet Explorer and Android 4.x -->
    <script src="https://cdn.polyfill.io/v3/polyfill.min.js?features=fetch,requestAnimationFrame,Element.prototype.classList,URL,TextDecoder,Number.isInteger"></script>
    <style>
      .map {
        width: 100%;
        height:400px;
      }
    </style>
  </head>
  <body>
    <div id="map" class="map"></div>
    <script src="main.js"></script>
  </body>
</html>

package.json

{
  "name": "dynamic-data",
  "dependencies": {
    "ol": "7.1.0"
  },
  "devDependencies": {
    "parcel": "^2.0.0-beta.1"
  },
  "scripts": {
    "start": "parcel index.html",
    "build": "parcel build --public-url . index.html"
  }
}

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动画展示数据

main.js

index.html

package.json

如果你对这篇内容有疑问，欢迎到本站社区发帖提问 参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。

发布评论

如果你对这篇内容有疑问，欢迎到本站社区发帖提问参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。