文章来源于网络收集而来，版权归原创者所有，如有侵权请及时联系！

图层层级（Z-Index）

发布于 2022-11-30 23:36:04 字数 4442 浏览 0 评论 0 收藏 0

本示例演示使用 Z-index 设置图层层级顺序。

本示例中有两个可管理图层（正方形和三角形；可管理图层指的是可操作）和一个非管理图层（五角星）。
Z-index 决定了渲染的顺序；地图的渲染参数为：{正方形: 1, 三角形: 0, 五角星: unmanaged}，渲染顺序为三角形，正方形，以及顶层的五角星。

main.js

import 'ol/ol.css';
import Feature from 'ol/Feature';
import Map from 'ol/Map';
import Point from 'ol/geom/Point';
import VectorLayer from 'ol/layer/Vector';
import VectorSource from 'ol/source/Vector';
import View from 'ol/View';
import {Fill, RegularShape, Stroke, Style} from 'ol/style';

const stroke = new Stroke({color: 'black', width: 1});

const styles = {
  'square': new Style({
    image: new RegularShape({
      fill: new Fill({color: 'blue'}),
      stroke: stroke,
      points: 4,
      radius: 80,
      angle: Math.PI / 4,
    }),
  }),
  'triangle': new Style({
    image: new RegularShape({
      fill: new Fill({color: 'red'}),
      stroke: stroke,
      points: 3,
      radius: 80,
      rotation: Math.PI / 4,
      angle: 0,
    }),
  }),
  'star': new Style({
    image: new RegularShape({
      fill: new Fill({color: 'green'}),
      stroke: stroke,
      points: 5,
      radius: 80,
      radius2: 4,
      angle: 0,
    }),
  }),
};

function createLayer(coordinates, style, zIndex) {
  const feature = new Feature(new Point(coordinates));
  feature.setStyle(style);

  const source = new VectorSource({
    features: [feature],
  });

  const vectorLayer = new VectorLayer({
    source: source,
  });
  vectorLayer.setZIndex(zIndex);

  return vectorLayer;
}

const layer0 = createLayer([40, 40], styles['star']);
const layer1 = createLayer([0, 0], styles['square'], 1);
const layer2 = createLayer([0, 40], styles['triangle'], 0);

const layers = [];
layers.push(layer1);
layers.push(layer2);

const map = new Map({
  layers: layers,
  target: 'map',
  view: new View({
    center: [0, 0],
    zoom: 18,
  }),
});

layer0.setMap(map);

function bindInputs(id, layer) {
  const idxInput = document.getElementById('idx' + id);
  idxInput.onchange = function () {
    layer.setZIndex(parseInt(this.value, 10) || 0);
  };
  idxInput.value = String(layer.getZIndex());
}
bindInputs(1, layer1);
bindInputs(2, layer2);

index.html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <title>Layer Z-Index</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>
    <div>
      <label for="idx1">
        <input type="number" id="idx1"></input>
        Square layer Z-index
      </label></br>

      <label for="idx2">
        <input type="number" id="idx2"></input>
        Triangle layer Z-index
      </label>
    </div>
    <script src="main.js"></script>
  </body>
</html>

package.json

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

分享到QQ

分享到微博

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

需要登录才能够评论，你可以免费注册一个本站的账号。

列表为空，暂无数据