I'm interested in filling out existing PDF forms programatically. All I really need to do is pull information from user input and then place the appropriate text over an existing PDF in the appropriate locations. I can already do this with reportlab by feeding the same sheet of paper into a printer, twice, but this just really rubs me the wrong way.

I'm tempted to just personally reverse engineer each existing PDF and draw every line and character myself before adding the user-inputted text, but I wanted to check to see if there was an easy way to take an existing PDF and set it as a background for some extra text. I'd really prefer to use python as it's the only language I feel comfortable with.

I also realize that I could just scan the document itself and use the resulting raster image as a background, but I would prefer the precision of vector graphics.

It seems like ReportLab has a commercial product with this functionality, and the specific function I'm looking for is in it (copyPages) - but it seems like overkill to pay for a 4 figure product for a single, simple function for a nonprofit use.