View Padding

本示例中演示 view 的 padding 选项参数.

本示例展示通过配置使地图视图适应被其他元素覆盖的 viewport 空间。如果地图的 viewport 的边缘被其他内容（viewport）部分覆盖，那么 padding 选项参数允许改变 viewport 的中心点（锚点），通过移动来适应地图位置。移位后的 viewport 中心将成为缩放控件放大缩小以及旋转的锚点。

使用 Alt+Shift+Drag 来旋转地图.

main.js

import GeoJSON from 'ol/format/GeoJSON.js';
import Map from 'ol/Map.js';
import View from 'ol/View.js';
import {Circle as CircleStyle, Fill, Stroke, Style} from 'ol/style.js';
import {OSM, Vector as VectorSource} from 'ol/source.js';
import {Tile as TileLayer, Vector as VectorLayer} from 'ol/layer.js';
import {fromLonLat} from 'ol/proj.js';

/** @type {VectorSource<import("../src/ol/geom/SimpleGeometry.js").default>} */
const source = new VectorSource({
  url: 'data/geojson/switzerland.geojson',
  format: new GeoJSON(),
});
const style = new Style({
  fill: new Fill({
    color: 'rgba(255, 255, 255, 0.6)',
  }),
  stroke: new Stroke({
    color: '#319FD3',
    width: 1,
  }),
  image: new CircleStyle({
    radius: 5,
    fill: new Fill({
      color: 'rgba(255, 255, 255, 0.6)',
    }),
    stroke: new Stroke({
      color: '#319FD3',
      width: 1,
    }),
  }),
});
const vectorLayer = new VectorLayer({
  source: source,
  style: style,
});
const view = new View({
  center: fromLonLat([6.6339863, 46.5193823]),
  padding: [170, 50, 30, 150],
  zoom: 6,
});
const map = new Map({
  layers: [
    new TileLayer({
      source: new OSM(),
    }),
    vectorLayer,
  ],
  target: 'map',
  view: view,
});

vectorLayer.getSource().on('featuresloadend', function () {
  const zoomtoswitzerland = document.getElementById('zoomtoswitzerland');
  zoomtoswitzerland.addEventListener(
    'click',
    function () {
      const feature = source.getFeatures()[0];
      const polygon = feature.getGeometry();
      view.fit(polygon);
    },
    false
  );

  const centerlausanne = document.getElementById('centerlausanne');
  centerlausanne.addEventListener(
    'click',
    function () {
      const feature = source.getFeatures()[1];
      const point = feature.getGeometry();
      view.setCenter(point.getCoordinates());
    },
    false
  );
});

index.html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <title>View Padding</title>
    <link rel="stylesheet" href="node_modules/ol/ol.css">
    <style>
      .map {
        width: 100%;
        height: 400px;
      }
      .mapcontainer {
        position: relative;
        margin-bottom: 20px;
      }
      .map {
        width: 1000px;
        height: 600px;
      }
      .map .ol-zoom {
        top: 178px;
        left: 158px;
      }
      .map .ol-rotate {
        top: 178px;
        right: 58px;
      }
      .map .ol-attribution,
      .map .ol-attribution.ol-uncollapsible {
        bottom: 30px;
        right: 50px;
      }
      .padding-top {
        position: absolute;
        top: 0;
        left: 0px;
        width: 1000px;
        height: 170px;
        background: rgba(255, 255, 255, 0.5);
      }
      .padding-left {
        position: absolute;
        top: 170px;
        left: 0;
        width: 150px;
        height: 400px;
        background: rgba(255, 255, 255, 0.5);
      }
      .padding-right {
        position: absolute;
        top: 170px;
        left: 950px;
        width: 50px;
        height: 400px;
        background: rgba(255, 255, 255, 0.5);
      }
      .padding-bottom {
        position: absolute;
        top: 570px;
        left: 0px;
        width: 1000px;
        height: 30px;
        background: rgba(255, 255, 255, 0.5);
      }

    </style>
  </head>
  <body>
    <div class="mapcontainer">
      <div id="map" class="map"></div>
      <div class="padding-top"></div>
      <div class="padding-left"></div>
      <div class="padding-right"></div>
      <div class="padding-bottom"></div>
    </div>
    <button id="zoomtoswitzerland">Zoom to Switzerland</button>
    <button id="centerlausanne">Center on Lausanne</button>
    <!-- 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": "view-padding",
  "dependencies": {
    "ol": "7.3.0"
  },
  "devDependencies": {
    "vite": "^3.2.3"
  },
  "scripts": {
    "start": "vite",
    "build": "vite build"
  }
}