OpenLayers源码解析8 ol/source/TileWMS.js ol/source/TileWMS.js
ol/source/TileWMS.js父类ol/source/TileImage-TileImage主要功能WMS服务提供的底图图层源。参数：TileWMS({})参数类型说明paramsObject.<string, *>至少需要LAYER参数。STYLE默认是’'VERSION默认是‘1.3.0’WIDTH，HEIGHT，BBOX，CRS会被动态设定hidpiboolean (defaults to true)使用ol/Map#pixelRa
