Create slides(Reveal.js) PNG images using phantomjs

shot.js

console.log('Loading a web page');
var page = require('webpage').create();
var url = 'http://localhost:1947/';
page.viewportSize = {
	width: 1024,
	height: 768
};
page.open(url, function (status) {
    //Page is loaded!
    var iz, i = 0, queue = {};

    iz = page.evaluate(function() {
      return document.querySelector('.slides').children.length;
    });

    console.log('total '+iz+' pages!');

    function createQueue(i) {

      return function() {
        console.log('rendering page of '+i+' ..............');
        page.evaluate(function(i) {
          Reveal.navigateTo(i);
        }, i);
        // waiting transition
        setTimeout(function() {
          var next = queue[(i+1)];
          page.render('./shot/shot-'+i+'.png');
          if (next) {
            next();
          } else {
            phantom.exit();
          }
          console.log('done '+i+'.');
        }, 1000);
      };
    }

    for (; i<iz; i++) {
      queue[i] = createQueue(i);
    }
    queue[0]();
});