some thoughts on screensavers in Plasma Workspaces 2

[Martin Graesslin]

On Sunday 13 January 2013 19:48:48 Aaron J. Seigo wrote:
> hi ..
> 
> side note 1: i've taken to refering to "future releases of Plasma Worskpaces
> that will use Frameworks 5 with libplasma2, Qt 5.1+ and QtQuick2" as Plasma
> Workspaces 2 (PW2) inside my head. if anyone has a better idea, speak up
> before it becomes a commonly used term :)
sounds good to me. In my last mail I referred to it as "Plasma 2".
> a) drop xscreensaver support altogether.
+1
> c) the current implementation of Widgets-on-screensaver is dropped
> completely. it woudl be replaced with a QML containment that also loads the
> unlock UI. this could in theory even be provided as a QML component itself
> so other unlockers could have widgets. this path means lockers will need to
> advertise whether or not they support widgets (default should probably be
> "yes" in such a case)
+1, keep in mind that currently we don't default to the widgets-on-
screensavers due to long loading and high probability of screen locker loads 
after system comes from suspend to RAM.

I hope that the startup time of a shell get's better with PW2 - especially 
being able to delay loading of elements through a QML LoaderItem and better 
threading should improve the situation. Nevertheless it has to be a design 
goal to have more or less instant locking. If the widgets are not loaded I 
don't care as long as there is at least the background item loaded.
> 
> something else we'll run into:
> 
> the unlock greeter needs to be ported to QML properly. right now and
> GreeterItem and KeyboardItem use QGraphicsProxyWidgets and this will break
> in QML2 w/scenegraph. that means kxkb needs to provide a proper QML
> component and the kgreet plugins in libs/kdm/ will need to turned into QML
> bits. the complication there is that kdm uses them as well ... so maybe
> some library duplication there, or .. we look at alternatives to kdm.
Back when I started to work on this I run into this issue. The keyboard item 
should not be that difficult but the kgreet plugin will be a nightmare. The 
complete logic is implemented inside a QWidget. The individual greeters just 
add further widgets to the base widgets. My fear is that we have to start from 
a blank sheet of paper and given that it is security related I must say that I 
don't like it. I'm not sure whether we have any experts on security in the 
workspaces team?

Random thought: we might have a look on whether we can do some re-usage of 
LightDM greeter bits. Maybe that's easier - David might give input on that.

Cheers
Martin