Plasma/Multiscreen

without the ZUI, we need an alternate way to access the containments of screens that aren't connected...

the latest plan:

• when PVD is deactivated, we offer to purge the unused containments (but, in user-speak of course). other than that, we ignore PVD, because a virtual desktop can always be readded (whereas a screen may be physically unavailable).
• the activity manager UI will use thumbnails generated from the view (look at the code in kdelibs/plasma/animations/widgetsnapshot.cpp to see

how to do this). hopefully we can save these thumbnails out when closing an activity..

• when the current activity has >1 screen, it'll have a thumbnail for each screen. you can click to bring a containment to the current screen, and there'll be delete buttons for ones not in use.
• when a screen is detached its containment is left running as it is now; the performance impact of this should be negligible.

Use cases

These are some use cases for multiscreen management of activities. They are paraphrased from conversations at plasma-devel.

• Jerry: "I usually use two screens, but pulled one screen off my desktop to use for a separate machine for longer-than-short-term. Now my main desktop has one screen, with the panel on it. I want to see in my only screen what was available in the removed screen".

• Chuk: "I'm working at the office with my laptop attached to a desktop monitor, with a 'Working' activity. I unplug the external monitor and take the laptop home where I use a 'Leisure' activity. Then I remember there was one note when I was using my monitor, and I need to read it in my laptop."

• Bugged man #1: "I have set a wallpaper with some plasmoids in my laptop, but every time I plug an external monitor KDE moves them to the monitor. I want to tell KDE to keep those plasmoids and wallpaper in the laptop."

• Bugged man #2: "I tried to set up a different wallpaper at each virtual desktop, but I didn't like it and disabled this feature. Now my system is slow, and someone on irc told me it's because all those other desktops are still running. I don't want to remove by hand all those extra desktops, the 'disable' button should have removed them."