I just want to bump this post and say that it is by far the best way [In my opinion] to create highly customizable and flexible PDF's via retool! No External libraires or API's required!
I was able to build a simple invoice program which allows the user to add 'line items' to a project, and it will print out a beatifully formatted invoice.
See attached Example:
The module @jmikem provided worked beautiflly. I just modifed the HTML template/handlebars data to my liking and voila - perfect invoicing system complete! Customer/Project management with billing - took all of a day or two.
Thanks again for your efforts!