Veyon patches

Veyon is free classroom supervision software, in C++ and Qt. Driving it on Ubuntu 26.04 with GNOME under Wayland, I fixed two defects and submitted my patches to the project, which accepted them at the end of September 2026. The first concerns the remote view on the teacher’s machine, the second the VNC server that relies on PipeWire to share the screen of a pupil’s workstation under Wayland.

For the remote view, three commits: the image is presented only once a whole update is decoded, which removes tearing, a full update is requested when quality improves, which avoids JPEG leftovers, and a reduced view is computed with smoothing rather than bilinear sampling, which makes text more even.

For the PipeWire server, the portal’s restore token is kept from one run to the next. It is an advanced option disabled by default, because this token opens sharing without a dialogue box to any process of the same user. The file is written with mode 0600, it is accepted only as a bare UUID, and it is no longer written to the log.

Without this kept token, the sharing dialogue box reappears at every start-up, in front of the pupil, who can cancel it. The plugin’s README nonetheless announced zero prompts after the first approval, which was true only for the length of one process. When a free tool blocks me, I fix it upstream rather than work around it, and these two patches are now part of the project.