We just merged the visual signature UI into Papers (GNOME Document Viewer), developed by Malika Asman during her Outreachy internship (funded by the GNOME Foundation ).

Compared to digital signatures, visual signatures do not require a cryptographic certificate. As such, they do not really guarantee the authenticity of a signed document, but they are still widely accepted or required (e.g. in administrative documents).

Here are a few screenshots, the two first ones are context menus that are shown when doing a right click on the document, the third one shows the drawing dialog.

It is possible to import an image file instead of drawing the signature in Papers. Malika implemented a background removal step so that signatures don't look like a plain picture on the document. This is done using the imageproc crate which implements Otsu's method (for those wondering, there is no neural networks or models involved). This gives good results on our test files, let's take for instance this cute GNOME contributor by Jakub : Once it is imported, the background is correctly removed and we can add this perplexed GNOME contributor to our PDFs:

Note that this is still a rather simple method, so we don't expect it to work in every case. If you have a file that can not be imported properly, please open an issue!

And digital signatures?

These new visual signatures cannot be used directly with digital signatures, but there are plans (and code) to extend the existing digital signature dialog to let users customize the way the signature is drawn on documents, including using one of the visual signatures.

There are other features that did not make it into this release, including the ability to copy/paste visual signatures, those will be for the next cycle!

Papers 51.beta

This is part of Papers 51.beta, there are a few other improvements and bug fixes, including a fix for fractional scaling taking advantage of latest GTK snapping API, read the news here .