phantomjs-截图比例

var webpage = require('webpage');
var page = webpage.create();
var url = "https://www.baidu.com/";

page.viewportSize = {width:480,height:800}
page.zoomFactor = 0.25;

page.open(url,function(s){
	if (s == "success") {
		page.render('baidu.jpeg',{format:'jpeg',quality:'100'});
		phantom.exit();
	};
});