PhantomJS zoomFactor 属性

var wpage = require('webpage').create(); 
wpage.zoomFactor;

var wpage = require('webpage').create(); 
wpage.zoomFactor = 0.3;  
wpage.open("http://www.google.com", function (status) {  
   window.setTimeout(function () { 
      wpage.render('output.png'); 
      phantom.exit(); 
   }, 200);  
});