When I try to generate PDF, I just get the following (example with version 2.1.3 and mPDF):
Warning: fopen(my_site/test.pdf): failed to open stream: No such file or directory in Mpdf\Mpdf->Output() (line 9625 of vendor/mpdf/mpdf/src/Mpdf.php).
More or less the same error is reported with any other PDF generator.
When I've downgraded printable to 2.0.3, I've got a more useful error report, pointing me to the conclusion that "my_site" folder is used twice in the generated PDF file path.
The simple solution is to create a symlink in "my_site" folder (my website root):
ln -s . "my_site" (a symlink actually pointing to the same folder)
After that, PDFs are nicely generated with printable 2.0.3 as well as 2.1.3 with mPDF.
With wkhtmltopdf, there is a logo image in PDF, but the text "{PAGENO} / {nb}" appears at the right upper corner.
With dompdf, there is no image and teh same text appears at the top of the generated PDF page.
With tcpdf, the same error still apperas, and no file is generated.