implement batch mode
batch mode automatically starts a scan after the previous one with a configurable time delay.
I found this useful for myself quite recently, even with a duplex ADF scanner. Some documents, e.g. folded multi-page certificates, can only be scanned with a flatbed scanner. The automatic but delayed scanning then makes this quite convenient. The batch mode is implemented with two custom options. One enables the batch mode, one configures the time delay between each scan. A countdown is presented when waiting for the next scan to start.
Skanlite automatically gains this feature through KSaneWidget. The countdown here starts after the image has been saved. The implementation for Skanpage is at https://invent.kde.org/astippich/skanpage/-/commits/batchMode.