The purpose of this crate is to provide a unified interface into rendering a PDF with different renderers. The PDF specification is complex, and for a PDF producer it's easy to do things wrong. Usually, just checking one PDF viewer is not enough to ensure that your PDF is devoid of undefined behavior, because it's possible that an invalid PDF just happens to display fine in one viewer, but not in others. Because of this, it's vital to check many different PDF viewers and check that they all display the PDF fine.

This crate supports six different rendering backends:

• Quartz (used by Apple Preview)
• pdfium (used by Google Chrome)
• pdf.js (used by Firefox)
• mupdf
• poppler
• pdfbox

By having access to these six renderers, you can be certain to a certain extent that if a PDF renders fine for all of them, there should be no major issues with the PDF. It's obviously no guarantee, but it at least gives some more confidence.

Most notably (and regrettably), the crate does not support rendering PDFs with Adobe Acrobat. This is unfortunate since it's clearly the most important viewer, but I was not able to figure out an easy way to render a PDF via a CLI, so it's unfortunately not supported for now.

Unfortunately, in order to use this crate it's not enough to just add it as a dependency. The way how sitro works is that it calls different command line utilities that render a PDF using some backend. For each backend you want to use, you need to set an environment variable to point to that renderer. Below you can find the requirements for each renderer.

For this renderer, you need to build the rust crate that you can find in src/pdfium. In addition to that, you also need to have the pdfium libray on your system so that it can be linked to statically. Then, you simply need to point the PDFIUM_BIN environment variable to the binary.

For this backend, you simply need the mutool utility somewhere on your system and point the MUPDF_BIN environment variable to it.

For this backend, you simply need the pdftoppm somewhere on your system and point the POPPLER_BIN environment variable to it.

For this backend, you need to have Java installed on your system. In addition, you need to point the PDFBOX_BIN binary to the .jar file.

For this backend, you need to have node.js on your system. Then you need to check out the src/pdfjs folder on your system and install the required node packages. Then, you simply need to point the PDFJS_BIN environment variable to the location of the pdfjs_render.mjs file.

This backend will only work on MacOS. You need to check out the src/quartz folder and run build.sh. Then, you simply point the QUARTZ_BIN environment variable to the quartz_render utility.

Note that this crate isn't in the best "shape" in terms of structure and documentation. The reason for this is that I mainly use it for personal purposes, so I didn't put a lot of effort into cleaning it up, and that's why it's also not released on crates.io. Nevertheless, it should still work fine for anyone who has the exact need of rendering a PDF with different backends.