Phantom Js image capturing issue - cakephp

Question

I am new to phantom js.I am using phantom js to create an image of a web page. It works fine for normal web pages, but webpages in which the content loads after scrolling are not getting captured properly.
I am using the following code to generate image:
PhantomJs Code (Desktop.js):
var page = require('webpage').create(),
system = require('system'),
address, output, size;
if (system.args.length < 3 || system.args.length > 5) {
console.log('Usage: rasterize.js URL filename [paperwidth*paperheight|paperformat] [zoom]');
console.log(' paper (pdf output) examples: "5in*7.5in", "10cm*20cm", "A4", "Letter"');
phantom.exit(1);
} else {
address = system.args[1];
output = system.args[2];
page.viewportSize = { width: 1280, height:200 };
if (system.args.length > 3 && system.args[2].substr(-4) === ".pdf") {
size = system.args[3].split('*');
page.paperSize = size.length === 2 ? { width: size[0], height: size[1], margin: '0px' }
: { format: system.args[3], orientation: 'portrait', margin: '1cm' };
}
if (system.args.length > 4) {
page.zoomFactor = system.args[4];
}
page.open(address, function (status) {
if (status !== 'success') {
console.log("status: " + status);
console.log('Unable to load the address!');
phantom.exit();
} else {
window.setTimeout(function () {
page.render(output);
phantom.exit();
}, 3000);
}
});
}
CakePhp Code:
$phantomjs_path = '/var/www/html/phantomjs/';
$url = 'http://springsummer.dk/'
$img_path = '/var/www/html/application/app/webroot/img/test.png'
$output = exec($phantomjs_path . 'bin/phantomjs --ssl-protocol=any ' . phantomjs_path . 'utilities/Desktop.js ' . $url . ' ' . $img_path );
I have also checked some post on stackoverflow regarding this problem, but they didn't helped.
Code after adding scrolling:
var page = require('webpage').create(),
system = require('system'),
address, output, size;
var height = 0;
if (system.args.length < 3 || system.args.length > 5) {
console.log('Usage: rasterize.js URL filename [paperwidth*paperheight|paperformat] [zoom]');
console.log(' paper (pdf output) examples: "5in*7.5in", "10cm*20cm", "A4", "Letter"');
phantom.exit(1);
} else {
address = system.args[1];
output = system.args[2];
page.viewportSize = { width: 1366, height:768 };
if (system.args.length > 3 && system.args[2].substr(-4) === ".pdf") {
size = system.args[3].split('*');
page.paperSize = size.length === 2 ? { width: size[0], height: size[1], margin: '0px' }
: { format: system.args[3], orientation: 'portrait', margin: '1cm' };
}
if (system.args.length > 4) {
page.zoomFactor = system.args[4];
}
console.log('Opening');
page.open(address, function (status) {
if (status !== 'success') {
console.log("status: " + status);
console.log('Unable to load the address!');
phantom.exit();
} else {
height = page.evaluate(function() {
window.scrollTop = document.body.scrollHeight;
return document.body.scrollHeight;
});
console.log(height);
page.viewportSize = { width: 1366, height: height };
console.log("Height set");
}
});
console.log('2nd');
if(height > 0){
console.log("Reloading...");
page.open(address, function(status){
if (status !== 'success') {
console.log("status: " + status);
console.log('Unable to reload the address!');
phantom.exit();
} else {
console.log("Capturing ...");
window.setTimeout(function () {
page.render(output);
phantom.exit();
}, 3000);
}
});
}
phantom.exit();
}