ScreenChecker.js

// ScreenChecker for AutoBot
var system = require('system');
var webpage = require('webpage');
var sizearr = [[320, 480], [768, 1024], [1280, 800], [1600, 990]];
var URL = "";
var debug = true; // prints a list of all urls checked
var verbose = false; // prints detailed arrays showing visited links and queued links
var cleanURL;
var sizearrcount = 3;
var resemblejs = require('./lib/resemble.js');

function delayRender() {
    if (sizearrcount === -1) {
        phantom.exit();
    }
    takeScreenshot(sizearr[sizearrcount][0], sizearr[sizearrcount][1], sizearrcount, delayRender);
    sizearrcount--;
}

function takeScreenshot(pagewidth, pageheight, count, callback) {

    // Count is undefined run the loop once
    if (typeof(count) === 'undefined') {
        count = 0;
    }

    var page = webpage.create(); //Creating a new page object

    // To ignore js errors in page scripts
    page.onError = function (msg, trace) {
        if (debug && verbose) {
            var msgStack = ['ERROR: ' + msg];
            if (trace && trace.length) {
                msgStack.push('TRACE:');
                trace.forEach(function (t) {
                    msgStack.push(' -> ' + t.file + ': ' + t.line + (t.function ? ' (in function "' + t.function + '")' : ''));
                });
            }
            console.error(msgStack.join('\n'));
        }
    };

    // Set viewport size
    page.viewportSize = {
        width: pagewidth,
        height: pageheight
    };

    page.open(URL, function (status) {
        if (status !== 'success') {
            console.log('Unable to open the URL! ' + status);
            phantom.exit();
        }
        else {
            result = page.evaluate(function () {
                return document.getElementsByTagName('html');
            });
            console.log("Generating screenshot for " + pagewidth + "x" + pageheight);
            page.render(cleanURL + '_' + pagewidth + 'x' + pageheight + '.png');
        }
        page.close();
        if (count === -1) {
            phantom.exit();
        }
        else {
            callback();
        }
    });
}

function compareResemble() {
    // Since resemble uses HTML5 canvas and javascript
    // we have to simulate the process of file read with the FileReader API
    // - inject 2 input tags in an html page
    // - upload the screenshot and the desired png
    // then use resemble to return an object in canvas which again has to be converted to an image
    phantom.exit();
}

if (system.args.length === 1) {
    console.log('Pass the URL of the website as argument to this script!');
    phantom.exit(1);
}
else {
    URL = system.args[1];
    cleanURL = URL.replace(/.*?:\/\//g, "");
    switch (system.args.length) {
        case 2:
            delayRender();
            break;
        case 3:
            var customSize = system.args[2].split('x');
            takeScreenshot(customSize[0], customSize[1], -1);
            break;
        case 4:
            compareResemble();
            break;
        default:
            phantom.exit();
            break;
    }
}