mapbox 加载两个raster图层，上边图层有白色的背景，一直遮盖下面图层。在leaflet中有transparent属性，可以设置背景透明。mapbox,怎么设置背景透明啊。下面是代码：
var map = new mapboxgl.Map({
container: 'map',
style: {
'version': 8,
'sources': {
'raster-tiles': {
'attribution': attribution,
'type': 'raster',
// 'transparent': true,
'tiles': ['
http://support.supermap.com.cn:8090/iserver/services/maps/rest/maps/World/zxyTileImage.png?prjCoordSys={"epsgCode":3857}&z={z}&x={x}&y={y}'],
'tileSize': 256
}
},
'layers': [{
'id': 'simple-tiles',
'type': 'raster',
'source': 'raster-tiles',
'minzoom': 0,
'maxzoom': 22
}],
'sprite': '
http://iclient.supermap.io/web/styles/street/sprite'
},
center: [0, 0],
maxZoom: 18,
zoom: 2
})
map.addControl(new mapboxgl.NavigationControl(), 'top-left')
map.on('load', () => {
debugger
map.addSource('firstLayer', {
type: 'raster',
// transparent: true,
tiles: ['
http://support.supermap.com.cn:8090/iserver/services/map-jingjin/rest/maps/京津地区地图/zxyTileImage.gif?prjCoordSys={"epsgCode":3857}&z={z}&x={x}&y={y}'],
// tiles: ['http://192.168.113.142:8090/iserver/services/map-waterfront/rest/maps/image/zxyTileImage.png?z={z}&x={x}&y={y}'],
tileSize: 256
})
map.addLayer({
id: 'firstLayer',
type: 'raster',
paint: {
'raster-opacity': 0.7,
// 'raster-transparent': true,
'raster-opacity-transition': {
'duration': 0
},
'raster-fade-duration': 5
},
source: 'firstLayer',
minZoom: 0
})
})
