Advanced View Positioning

高级视图定位

(best fit).
(with min resolution),

此示例演示如何调整地图视图，使几何图形或坐标定位在特定的像素位置。

本示例演示如何调整地图视图，使几何图形或坐标定位在特定的像素位置。上方的地图在视口内应用了上、右、下、左内边距。视图的 fit 方法用于在视图中以相同的内边距适配几何图形。视图的 centerOn 方法用于将坐标（洛桑）定位到特定的像素位置（黑框的中心）。

使用 Alt+Shift+Drag 旋转地图。

注意：本示例不会移动视图中心。因此缩放控件和旋转地图仍将使用视口中心作为锚点。要根据内边距移动整个视图，请使用视图的 padding 选项，如 view-padding.html 示例所示。

main.js

import Map from 'ol/Map.js';
import View from 'ol/View.js';
import GeoJSON from 'ol/format/GeoJSON.js';
import TileLayer from 'ol/layer/Tile.js';
import VectorLayer from 'ol/layer/Vector.js';
import OSM from 'ol/source/OSM.js';
import VectorSource from 'ol/source/Vector.js';

const source = new VectorSource({
  url: 'data/geojson/switzerland.geojson',
  format: new GeoJSON(),
});

const vectorLayer = new VectorLayer({
  source: source,
  style: {
    'fill-color': 'rgba(255, 255, 255, 0.6)',
    'stroke-width': 1,
    'stroke-color': '#319FD3',
    'circle-radius': 5,
    'circle-fill-color': 'rgba(255, 255, 255, 0.6)',
    'circle-stroke-width': 1,
    'circle-stroke-color': '#319FD3',
  },
});

const view = new View({
  center: [0, 0],
  zoom: 1,
});
const map = new Map({
  layers: [
    new TileLayer({
      source: new OSM(),
    }),
    vectorLayer,
  ],
  target: 'map',
  view: view,
});

const zoomtoswitzerland = document.getElementById('zoomtoswitzerland');
zoomtoswitzerland.addEventListener(
  'click',
  function () {
    const feature = source.getFeatures()[0];
    const polygon = feature.getGeometry();
    view.fit(polygon, {padding: [170, 50, 30, 150]});
  },
  false,
);

const zoomtolausanne = document.getElementById('zoomtolausanne');
zoomtolausanne.addEventListener(
  'click',
  function () {
    const feature = source.getFeatures()[1];
    const point = feature.getGeometry();
    view.fit(point, {padding: [170, 50, 30, 150], minResolution: 50});
  },
  false,
);

const centerlausanne = document.getElementById('centerlausanne');
centerlausanne.addEventListener(
  'click',
  function () {
    const feature = source.getFeatures()[1];
    const point = feature.getGeometry();
    const size = map.getSize();
    view.centerOn(point.getCoordinates(), size, [570, 500]);
  },
  false,
);

index.html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <title>Advanced View Positioning</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);
      }
      .center {
        position: absolute;
        border: solid 1px black;
        top: 490px;
        left: 560px;
        width: 20px;
        height: 20px;
      }
    </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 class="center"></div>
    </div>
    <button id="zoomtoswitzerland">Zoom to Switzerland</button> (best fit).<br/>
    <button id="zoomtolausanne">Zoom to Lausanne</button> (with min resolution),<br/>
    <button id="centerlausanne">Center on Lausanne</button>

    <script type="module" src="main.js"></script>
  </body>
</html>

package.json

{
  "name": "center",
  "dependencies": {
    "ol": "10.9.0"
  },
  "devDependencies": {
    "vite": "^3.2.3"
  },
  "scripts": {
    "start": "vite",
    "build": "vite build"
  }
}