Feature Request: Preview the contents of displays within the Dashboard

[rmscode]

I really like being able to manage all of my DietPi devices from your dashboard and think it would be great if we could preview what content is currently running on a display. I'm not asking for a live feed, but maybe a screenshot taken every 30 seconds or so. I have deployed several Raspberry Pi's for use as digital signage/kiosks and it can be a pain to walk to the device, sometimes a decent distance, to make sure the content is being displayed correctly.

[MichaIng]

Linking the discussion: MichaIng/DietPi#7040

Definitely not trivial, requires different methods depending on how the display is accessed:

• fbcat (man) for console mode.
• xwd from x11-apps package for X sessions.
• No idea how to achieve this when something is printing to screen via DRM/KMS directly, or frameworks like SDL.

If we find ways to cover all relevant cases and time to implement it, I would vote for screenshot on demand, hence when accessing the related dashboard page, and additionally a button to trigger new ones. Those could be kept small and in TMP, and removed when switching navigating to anther page. And they must have 0600 mode, to assure no one but root/dashboard can see them, else it is a security and privacy risk.