There is a much more awesome version made by Denys Vitali available on his github
I reversed engineered part of Squid (ex Papyrus) application page storage
format which is based on Google Protocol Buffers.
I rewrote part of the format .proto file and wrote a demonstration script which uses protobuf and
cairo to convert Squid page file into SVG.
You can obtain those pages by making a local or cloud backup. This creates a file called
papyrus.bak which is in fact a zip file. In the zip you'll find an info.json file, a
papyrus.db database file and a data directory. The pages are located in data/pages.
Page names correspond to UUIDs. The database (which is a SQLite3 database) links those UUID with notes and notebooks.
From a limited reverse engineering of the application you can discover it uses the
Wire Protocol Buffer to generate java files from Google Protocol
Buffers definition of the Squid Page format. I thus simply reconstructed the .proto file from
those reversed java files.
So far the stroke part of the format (which is also used by the rectangle and line tools) and, thanks to Denys Vitali, the ellipses and text are fully reversed. The following features are not reversed engineered:
- Paper background
- PDF background
- Image tool
Feel free to open an issue if you need it and encourage me to reverse engineer it. Or send a pull request if you've implemented it.
The page2svg.py tool can be simply used with the following command:
python2 page2svg.py <Input Squid page file> <Output SVG>
page2svg.py is supposed to demonstrate how you can interpret the Squid Page format.
I made this work under the fair assumption it is covered by the exceptions of the section 1201 of the Digital Millennium Copyright Act: https://www.eff.org/fr/issues/coders/reverse-engineering-faq#faq9