another interesting bug.. this time performance related

Marco Martin notmart at
Sat Feb 19 15:03:23 CET 2011

On Saturday 19 February 2011, Aaron J. Seigo wrote:
> hey all ...
> here's another interesting little bug:
> it seems we have some excess cpu usage in the system monitor plasmoids.
> needs some investigating, but it's certainly reproducable. if anyone wants
> to take it on, that'd be awesome.
> and in case anyone is interested what i'm doing (pffft, why :P ), i've
> continued to work on both the calendar event layout and the tasks widget.
> in fact, i came to the conclusion after wasting ~2 hours futzing with the
> tasks plasmoid that the animated layout on top of QGraphicsGridWidget is a
> failure. it's ok, and the code does some impressive things given the
> limitations, but it's just not Good Enough(tm) and it simply _can't_ be.
> so i've started working on a replacement for it. a properly animated grid
> layout that's a subclass of QGraphicsLayout. fun.
eh, will be fun, yeah ;)
also the positioning in multi line is fun as well.
and correct propagating of size hints without the possibility to access into 
qgraphicslayoutitem privates... ;)
related note, on the search and lauch, since 4.6 where i dropped the 
qgraphicsgridlayout and position icons by hand without -any- qgraphicslayout, 
everything started to work magically better :p

crazy idea: what about qml-ifing the taskbar right now?
since is the most complex applet will still be a c++ one (that would just show 
a DeclarativeWidget and nothing else)

i have no idea how much work would take, the only hard thing seems to be a 
correct handling of grouping (i guess it will have to be written a 
qabstractitemmodel that maps to what libtaskmanager says)
for the positioning and animate flowing there is *exactly* what we need
the Flow positioner item, containing a Repeater hooked up to the model for the 
tasks, so there *could* be even less work in doing that rather than writing a 
qgrphicslayout subclass, that is the most hairy thing ever ;)

(on a related note, i almost have a working systray in pure qml, since the 
mobile one thankfully doesn't support the xembed icons, it may be usable soon 

Marco Martin

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