Scale image before toDataURL - html2canvas

I had bit similar problem and this is what I ended up doing

html2canvas($('#div_id'), {width: 750, height: 1050}).then(
    function(canvas) {
       window.open(canvas.toDataURL("image/png"));
    }
)

Now this still lead to blurry images (especially with text), but that was because my default zoom on browser was set to 110% those causing the window.devicePixelRatio to be 1.1000... I sorted that out by simply showing warning for user (worked for the purpose I need it), but apparently there is a better way to solve it https://stackoverflow.com/a/22819006/460586

For anyone else wondering how to get high-res print-worthy content from html: PhantomJS and wkhtmltopdf / wkhtmltoimage are great alternatives that handle these things better.