Html2Canvas only renders viewport

Question

Using html2canvas to try to create pdfs and/or pngs and its working, except it only renders the visible section of the screen.

Anyone have any idea how to fix this?

//create pdf

$(document).ready(function() {
$('#downloadpdf').click(function() { 
    html2canvas($("#fullreporttoprint"), {
        onrendered: function(canvas) {         
            var imgData = canvas.toDataURL(
                'image/png');              
            var doc = new jsPDF('p', 'mm');
            doc.addImage(imgData, 'PNG', 10, 10);
            doc.save('mywindassessment.pdf');
        }
    });
});
});

Before someone marks this, I've checked everywhere online and SO for this problem, and was unable to find a working solution.