Animated GIF

地图加载 GIF 动图

animation 5 vector 72 style 24 icon 9 gif 1

本示例演示将动画 GIF 作为 icon 加载到地图上.

本示例演示将动画 GIF 作为 icon 加载到地图上。动图是使用 Gifler 库实现的。

main.js

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

const iconFeature = new Feature({
  geometry: new Point([0, 0]),
});

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

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

const rasterLayer = new TileLayer({
  source: new Stamen({
    layer: 'toner',
  }),
});

const map = new Map({
  layers: [rasterLayer, vectorLayer],
  target: document.getElementById('map'),
  view: new View({
    center: [0, 0],
    zoom: 2,
  }),
});

const gifUrl = 'data/globe.gif';
const gif = gifler(gifUrl);
gif.frames(
  document.createElement('canvas'),
  function (ctx, frame) {
    if (!iconFeature.getStyle()) {
      iconFeature.setStyle(
        new Style({
          image: new Icon({
            img: ctx.canvas,
            imgSize: [frame.width, frame.height],
            opacity: 0.8,
          }),
        })
      );
    }
    ctx.clearRect(0, 0, frame.width, frame.height);
    ctx.drawImage(frame.buffer, frame.x, frame.y);
    map.render();
  },
  true
);

// change mouse cursor when over icon
map.on('pointermove', function (e) {
  const pixel = map.getEventPixel(e.originalEvent);
  const hit = map.hasFeatureAtPixel(pixel);
  map.getTarget().style.cursor = hit ? 'pointer' : '';
});

index.html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <title>Animated GIF</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 src="https://cdn.jsdelivr.net/npm/gifler@0.1.0/gifler.min.js"></script>
    <script type="module" src="main.js"></script>
  </body>
</html>

package.json

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