Map view extent

by Vladimir Vershinin

HTML

<script src="https://unpkg.com/vue@latest/dist/vue.min.js"></script>
<script src="https://cdn.jsdelivr.net/gh/openlayers/openlayers.github.io/en/v5.3.0/build/ol.js"></script>
<script src="https://unpkg.com/[email protected]/lib/index.umd.js"></script>
<link rel="stylesheet" href="https://unpkg.com/[email protected]/lib/style.css">
<div id="app">
  <div>
    View extent: {{ extent }}
  </div>
  <vl-map ref="map" data-projection="EPSG:4326">
    <vl-view ref="view"
             :zoom.sync="zoom" 
             :center.sync="center"
             @mounted="viewMounted"></vl-view>
    <vl-layer-tile>
      <vl-source-osm></vl-source-osm>
    </vl-layer-tile>
    
  </vl-map>  
</div>

CSS

html, body, #app {
  width: 100%;
  height: 100%;
  margin: 0;
  padding: 0;
}

#app {
  display: flex;
  flex-direction: column;
}

.vl-map {
  overflow: hidden;
}

JavaScript

new Vue({
	el: '#app',
  data () {
  	return {
    	zoom: 2,
      center: [0, 0],
      extent: undefined,
    }
  },
  watch: {
  	center () {
    	this.updateExtent()
    },
  },
  methods: {
  	viewMounted () {
    	this.updateExtent()
    },
    updateExtent () {
    	/** @var {ol/View} olView */
    	const olView = this.$refs.view.$view
      if (olView == null) return
    
    	this.extent = ol.proj.transformExtent(olView.calculateExtent(), 'EPSG:3857', 'EPSG:4326')
    },
  },
})