Show HN: Tetris in a PDF

I realized that the PDF engines of modern desktop browsers (PDFium and PDF.js) support JavaScript with enough I/O primitives to make a basic game like Tetris.

It was a bit tricky to find a union of features that work in both engines, but in the end it turns out that showing/hiding annotation "fields" works well to make monochrome pixels, and keyboard input can be achieved by typing in a text input box.

All in all it's quite janky but a nice reminder of how general purpose PDF scripting can be. The linked PDF is all ASCII so you can just open it in a text editor, or have a look at the source code here: https://github.com/ThomasRinsma/pdftris/blob/main/gengrid.py

Show HN: Tetris in a PDF
th0mas.nl

Genius you mean ?

Brilliant!

Not just web browsers, Acrobat (and probably other PDF readers) have supported executing Javascript in PDFs for decades.

Back in school pdfs would circulate that had a bunch of flash games on them. I have no idea how or who made them, but they let us play dolphin olympics on lab computers with no internet connection.