Libraries

Choosing which PDF manipulation library to use is an important decision for PDF Ink users. PDF Ink comes with a couple free library sets, but it also allows you to upgrade to better, paid libraries. The magic behind the curtain can be a little confusing, so let's try to clear up the difference between PDF reading and writing libraries and how they are used with PDF Ink. And of course, which to choose?

(If you are only using PDF Ink for EPUB, don't worry about libraries.)

While there are quite a few PDF-handling software libraries out there, there are only a handful of pertinent, quality ones built on PHP. Several of those are included in PDF Ink: TCPDI, FPDI, TCPDF, and FPDF.

The software libraries used by PDF Ink are written and maintained by outside (3rd party) developers. PDF Ink knits all these libraries together — and connects them to WordPress and WordPress e-commerce plugins. Here are what your library choices look like in the PDF Ink settings:

Screenshot of PDF Ink plugin settings page showing potential choice of PHP PDF manipulation libraries, in an HTML select. Includes TCPDF, FPDF and SetaPDF-Stamper, and more.

The starred choices include paid third-party add ons. Frankly, they work the best. Each selection shows a reader + writer, except SetaPDF-Stamper, which is itself a reader and a writer combined.

It’s safe to start with the default selection, and if it doesn’t work with your PDF, try another library set.

We wrote a long post about readers and writers if you are curious to know more.

Our Recommendation

  1. Start with the included libraries – give TCPDI/TCPDF or FPDI/TCPDF or FPDI/FPDF a quick try.
  2. If they work, you’re all set – no extra cost, no hassle.
  3. If they don’t, we have a smooth upgrade path that keeps everything working with PDF Ink.

Upgrade Paths

  1. If you like FPDI and wish it would work with PDF files versioned 1.5 and newer, upgrade to using FPDI PDF-Parser with PDF Ink.
  2. If you need full PDF fidelity (for PDF forms, layers, table of contents (ToC) and other internal links, annotations, PDF actions), upgrade to using SetaPDF Stamper with PDF Ink

Both upgrades come from the wonderful folks at SetaSign. They’re friendly, responsive, and their product is top‑notch.

Our support promise

We take care of PDF Ink – it’s fully supported and maintained by us.

The third‑party libraries (TCPDI, FPDI, SetaPDF, etc.) are maintained by their own teams. When you choose a paid library, you also get the peace of mind that comes with the vendor’s direct support.

A little extra for you

When you purchase PDF Ink, you’ll receive a 20% discount code for SetaPDF Stamper and FPDI PDF-Parser.

Further information

Try the different libraries on your PDF (online PDF Ink demo) 👀

Which PDF Manipulation Library to Use? (2020 blog post)

TCPDI on GitHub

FPDI on GitHub

TCPDF on GitHub

FPDF.org

A post about the differences between TCPDF and FPDF (by Yunus Emre Adas)

SetaPDF Stamper