Snappy / WKHTMLtoPDF - How to change the save folder - pdf

Question

I'm using Laravel with the snappy wrapper. It is all working except that it saves the PDF's into the public folder. I want it to go to a different folder. There is nothing obvious on the snappy git site, nor in the config. And the wkhtlptopdf docs are very sparse imho. How do I change the $pdf->save() statement so it goes where I want it to go ?
My PDF is generated by laravel like this:
if( $email == 'email'){
$quotation = $this->quotation->get_PdfQuote($ref);
$pdf = PDF::loadView('quotations/pdf_quotation',compact('quotation') );
$pdf->save($ref.'.pdf'); //THIS SAVES INTO THE PUBLIC FOLDER.
$title = 'Your Quotation';
$firstname = $customer['firstname1'];
$pathtoFile = '/var/www/auburntree/public/'.$ref.'.pdf';
Mail::send('emails.quotation', ['title' => $title, 'firstname'=>$firstname ], function ($m) use($customer,$pathtoFile) {
$m->from('myemail#gmail.com', 'Auburntree');
$m->to($customer['email1'],($customer['firstname1'] . $customer['lastname1']))->subject('Your Quotation');
$m->attach($pathtoFile);
});
Flash::success('The Quote Has Been Saved. An Email has ben sent to the customer ');
return redirect ('quotes');
} else

Answer 1

Ok, I hope this helps someone else.
$quotation = $this->quotation->get_PdfQuote($ref); //pulled in from DB
$pdf = PDF::loadView('quotations/pdf_quotation',compact('quotation') );
$filename = base_path('public/pdf/'.$ref.'.pdf');
$pdf->save($filename);