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鐵人賽 神助攻 HERE Technologies

HERE API Example - 限制地圖移動

本文範例主要功能為限制 HERE 地圖移動,當渲染地圖與視圖模型資料進行同步時就會觸發 sync 事件,透過監聽 sync 事件,可以將 map.center 的值限制在一定範圍內。

JavaScript

/**
 * 限制 HERE 地圖移動於限定的矩形區域 *
 */
function restrictMap(map){

  var bounds = new H.geo.Rect(23, 120, 23.5, 120.5 );
  map.getViewModel().addEventListener('sync', function() {
    var center = map.getCenter();

    if (!bounds.containsPoint(center)) {
      if (center.lat > bounds.getTop()) {
        center.lat = bounds.getTop();
      } else if (center.lat < bounds.getBottom()) {
        center.lat = bounds.getBottom();
      }
      if (center.lng < bounds.getLeft()) {
        center.lng = bounds.getLeft();
      } else if (center.lng > bounds.getRight()) {
        center.lng = bounds.getRight();
      }
      map.setCenter(center);
    }
  });

  // Debug code: 視覺化可限制的範圍
  map.addObject(new H.map.Rect(bounds, {
    style: {
        fillColor: 'rgba(60, 85, 170, 0.1)',
        strokeColor: 'rgba(60, 85, 170, 0.6)',
        lineWidth: 8
      }
    }
  ));
}

/**
 * 初始化地圖
 */

//Step 1: 初始化 platform
var platform = new H.service.Platform({
  apikey: window.apikey
});
var defaultLayers = platform.createDefaultLayers();

//Step 2: 初始化 map,並指定中心為嘉南地區
var map = new H.Map(document.getElementById('map'),
  defaultLayers.vector.normal.map,{
  center: {lat: 23.29 , lng:120.41},
  zoom: 10 ,
  pixelRatio: window.devicePixelRatio || 1
});

window.addEventListener('resize', () => map.getViewPort().resize());

//Step 3: 建立互動性
var behavior = new H.mapevents.Behavior(new H.mapevents.MapEvents(map));

// Step 4: 建立預設 UI:
var ui = H.ui.UI.createDefault(map, defaultLayers, 'en-US');

restrictMap(map);

HTML

<!DOCTYPE html>
<html>
  <head>
    <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=yes">
    <meta http-equiv="Content-type" content="text/html;charset=UTF-8">
    
    <title>限制地圖移動</title>
    <link rel="stylesheet" type="text/css" href="https://js.api.here.com/v3/3.1/mapsjs-ui.css" />
    <link rel="stylesheet" type="text/css" href="demo.css" />
    <link rel="stylesheet" type="text/css" href="styles.css" />
    <link rel="stylesheet" type="text/css" href="../template.css" />
    <script type="text/javascript" src='../test-credentials.js'></script>
    <script type="text/javascript" src="https://js.api.here.com/v3/3.1/mapsjs-core.js"></script>
    <script type="text/javascript" src="https://js.api.here.com/v3/3.1/mapsjs-service.js"></script>
    <script type="text/javascript" src="https://js.api.here.com/v3/3.1/mapsjs-ui.js"></script>
    <script type="text/javascript" src="https://js.api.here.com/v3/3.1/mapsjs-mapevents.js"></script>
  </head>
  <body id="markers-on-the-map">

    <div class="page-header">
        <h1>限制地圖移動</h1>   
    </div>
    <div id="map"></div>   
    <script type="text/javascript" src='demo.js'></script>
  </body>
</html>

CSS

#map {
    width: 95%;
    height: 450px;
    background: grey;
}

#panel {
    width: 100%;
    height: 400px;
}

執行結果
https://ithelp.ithome.com.tw/upload/images/20201013/20012621tSbgcjrLG6.png


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