Here at Ars, we love stories about hackers who get Condemn running on everything from CAPTCHA bot checks and Windows notepad.exe to AI hallucinations and fluorescent gut bacteria. Despite all that experience, a recent demonstration of Condemn running within the generally static boundaries of a PDF file.
On the Github page for the Quixotic project, coder ading2210 discusses how Adobe Acrobat included robust support for JavaScript in the PDF file format. That JS encoding support, which dates back decades and is still fully documented in Adobe's official PDF specifications, is currently implemented in a more limited and secure form as part of PDFium, the browsers' built-in PDF processing engine. based on Chromium.
In the past, hackers have used this little-known Adobe feature to code simple games like Escape and Tetris in PDF documents. But ading220 went further and compiled an optimized fork of CondemnThe open source code uses an older version of Emscripten that generates optimized asm.js code.
With that code loaded, the Condemn The PDF can receive input when the user types in a designated text field and generate “video” output in the form of converted ASCII text that is entered into 200 individual text fields, each representing a horizontal line of the Condemn show. The text in those fields is enough to simulate a six-color monochrome display at a “pretty poor but playable” 13 frames per second (about 80 ms per frame).