CasperJS Fitted Screenshot

var casper = require('casper').create();
/* var url = casper.cli.args[0]; */

var url = 'http://kicker.de';
var fn = url.replace(/[^a-z0-9]/gi, '').toLowerCase();

// Settings
var targetWidth = 800; //final Image Size
var targetHeight = 600;
var maxWidth = 2800;

var width = targetWidth; 
var height = targetHeight;
var step = 50;

casper.start().viewport(targetWidth, targetHeight).thenOpen(url, function() {
    
    var hasHorizontalScrollbar = true;

    while (hasHorizontalScrollbar){

        // Remove if you dont want to see the steps
        this.capture(fn+'-'+width+'.png', {'top':0, 'left':0, 'width':width, 'height':height});

        // Check if a Scrollbar is necessary (as opposed to visibile, which could be changed by site)
        hasHorizontalScrollbar = this.evaluate(function(){
            var root = document.compatMode == 'BackCompat' ? document.body : document.documentElement;
            var hasHorizontalScrollbar = root.scrollWidth > root.clientWidth;
            return hasHorizontalScrollbar
        });

        console.log('hasHorizontalScrollbar: ' + hasHorizontalScrollbar);

        if(hasHorizontalScrollbar){
            
            width += step;
            if (width > maxWidth) break;

            height = parseFloat((width * 0.75).toFixed(0));;
            console.log('increasing width to ' + width);       
            this.viewport(width, height);
        }
			 	
    }
    var zoomFactor = targetWidth / width;
    this.zoom(zoomFactor).viewport(targetWidth, targetHeight, function() {
        // new view port is effective
        this.capture(fn+'-fitted.png', {'top':0, 'left':0, 'width':targetWidth, 'height':targetHeight});
    });
    
	
});

casper.run();