PDF to KFX Print Replica

[alphonk]

PDF to KFX Print Replica

Convert any PDF into a real KFX Print Replica for the Kindle Scribe, generated locally through calibre. No Send to Kindle, no Amazon account, no uploading your PDFs anywhere. Batch converts your whole library in one go.

Why this exists
Annotating a PDF on the Scribe has always worked reliably one way: send it through Send to Kindle as "original layout," which converts it into a real Print Replica KFX. Sideloading a PDF directly over USB is a different story. Support for writing on sideloaded PDFs is inconsistent across devices, several users report the markup tools not showing up at all, and even when they do, the annotations don't survive the transfer back to a computer and there's no way to export them by email.

This plugin builds that same Print Replica KFX yourself, offline, through calibre. The output is a genuine Print Replica (yj_textbook + yj_pdf_support), with the original PDF embedded as a resource and correct page by page rendering. Ink and zoom behave properly, tested on a real Kindle Scribe.

Not affiliated with Amazon. Uses the community KFX Output plugin (by jhowell) for the final KPF to KFX step. It needs to be installed for this plugin to work.

Usage

• Select one or more PDF books in your calibre library
• Click the PDF to KFX Replica toolbar button (or Ctrl+Shift+R)
• A KFX format is added to each book, titled from its metadata
• Send the book to your Scribe as usual, over USB or with calibre's "Send to device"

Important: calibre's "Send to device" will work, but only if it actually picks the KFX over the PDF. By default calibre may prefer the PDF format if both exist on the book. Go to Preferences > Output Options (or your device's format priority list) and either uncheck PDF as an accepted format for your Scribe, or move KFX above PDF in the priority order. Since the KFX already contains your PDF rendered as a writable Print Replica, the Scribe has no real use for the PDF format anyway.

Also available

• Standalone GUI that doesn't touch your calibre library. Double click PDF2KFX.command on macOS, or run it via calibre-debug
• Command line: calibre-debug pdf2kfx.py -- input.pdf output.kfx --title "My Title"

Requirements
calibre (tested on 9.2.1) with the KFX Output plugin (by jhowell) installed.
macOS, Windows, Linux. Everything else runs on calibre's bundled Python (podofo, Pillow, kfxlib), no extra dependencies.

License
MIT for this plugin. Respects the licenses of the upstream projects it builds on (KPF generation started from HankunYu's pure Python KPF generator).