MapBox GL 地图页面保存为图片的方法

时间：2020-01-10 18:51:21 阅读：363 评论：0 收藏：0 [点我收藏+]

标签：man col def let container rac inter 存储代码

MapBox GL没有自带的截图api，在github上有人写了一个控件 https://github.com/geolonia/mbgl-export-control。

但控件只能以固定的方式使用，本人做了一下改动：

核心代码如下：

 1 import ‘canvas-toBlob‘
 2 import FileSaver from ‘file-saver‘
 3 import mapboxgl from ‘mapbox-gl‘
 4 
 5 function setStyles (element, styles) {
 6   for (const style in styles) {
 7     element.style[style] = styles[style]
 8   }
 9 }
10 
11 export default function (map, name) {
12   const actualPixelRatio = window.devicePixelRatio
13   Object.defineProperty(window, ‘devicePixelRatio‘, {
14     get: () => 300 / 96
15   })
16 
17   const _container = document.createElement(‘div‘)
18   document.body.appendChild(_container)
19 
20   const width = map.getContainer().offsetWidth
21   const height = map.getContainer().offsetHeight
22   // const bottomRight = map.unproject([width, height]).toArray()
23 
24   setStyles(_container, {
25     visibility: ‘hidden‘,
26     position: ‘absolute‘,
27     top: 0,
28     bottom: 0,
29     width: `${width}px`,
30     height: `${height}px`
31   })
32 
33   let fontFamily = []
34   if (map.style.glyphManager && map.style.glyphManager.localIdeographFontFamily) {
35     fontFamily = map.style.glyphManager.localIdeographFontFamily
36   }
37 
38   let MBGL = mapboxgl.Map
39   const _map = new MBGL({
40     container: _container,
41     center: map.getCenter(),
42     zoom: map.getZoom(),
43     bearing: map.getBearing(),
44     pitch: map.getPitch(),
45     style: map.getStyle(),
46     localIdeographFontFamily: fontFamily,
47     hash: false,
48     preserveDrawingBuffer: true,
49     interactive: false,
50     attributionControl: false
51   })
52 
53   _map.once(‘load‘, () => {
54     _map.getCanvas().toBlob((blob) => {
55       FileSaver.saveAs(blob, name + ‘.png‘)
56       _map.remove()
57       _container.parentNode.removeChild(_container)
58       _loading.parentNode.removeChild(_loading)
59       Object.defineProperty(window, ‘devicePixelRatio‘, {
60         get: () => actualPixelRatio
61       })
62     })
63   })
64 }