liquidshell in kdereview

Martin Koller kollix at
Tue Nov 7 19:08:59 GMT 2017

On Dienstag, 7. November 2017 16:42:40 CET Martin Flöser wrote:
> Am 2017-11-03 21:30, schrieb Martin Koller:
> > Hi all,
> > 
> > I'd like to announce an application I've implemented over the last few
> > weeks - liquidshell
> > 
> > liquidshell is a replacement for plasmashell
> > 
> > It does not use QtQuick but instead relies on QtWidgets,
> > therefore no hardware graphics acceleration is needed.
> [snip]
> > The main motivation was to have a reliable desktop shell which does
> > not hog the CPU or RAM.
> > (CPU usage and stability were the things driving me mad with 
> > plasmashell)
> > It should be slick and have just the features I need in my daily
> > work. No need having all the bells and whistles anyone can think of.
> > Just have a plain, solid, fast workhorse.
> I'm now playing devils advocate: which window manager are you using?

personally I'm using kwin, since I only replaced plasmashell,
but I assume this is irrelevant to what "shell" one is using.

> If I understand correctly this is supposed to be a replacement for 
> plasmashell in Plasma, which would mean that you use KWin.

> Are you aware that KWin uses QtQuick for all its UI elements, such as 
> Alt+TAB?

I have deactivated the compositor since sadly it simply does not work
on my laptop (the intel graphics driver just freezes the whole machine).

> Isn't that also a memory and resource hog?

not here. It's not in the top 10 processes of CPU or memory usage

> Shouldn't you come up with a replacement for KWin as well?

no (as long as it works good enough for me)
> Also concerning no hardware graphics acceleration needed: who is going 
> to render your UI? Do you really think the QPainter API is the best and 
> most efficent to render a UI? Especially considering that in the end the 
> whole thing needs to be transferred to the GPU. Are you aware that the 
> compositor uses hardware acceleration to render the UI? If you don't use 
> a compositor: are you aware that XServer itself uses hardware 
> acceleration to render its UI (check glamor). Are you aware that if you 
> don't have hardware acceleration everything is going to be rendered 
> through llvmpipe? Do you really think QPainter is better than llvmpipe? 
> Because I - having worked with that stuff for years in a low level area 
> - doubt so.

You're barking at the wrong tree.
I don't care how it's done deep down in the stack.
I can tell you that now with liquidshell my CPU uses 0% CPU most of the time, 
and starting plasmashell it's more - sometimes much, much more without changing
anything in the workspace setup. That is simply not acceptable for me.
If plasmashell would work better, I would not have created liquidshell
in the first place.
Just wanting to WORK with my system, which I simply could not with plasmashell.

> I don't mind what you develop in your spare time. Not at all. What I 
> mind is if a product is added to KDE as a competitor/replacement to a 
> product I work on because of misunderstood things. What I see here is 
> that you completely misunderstood what hardware acceleration means and 
> gives to the system.

See above. I did not start liquidshell because I was bored. Believe me, I have other hobbies.
I started it just because I got fed up with the problems I had with plasmashell
and I need to use some DE for my daily work. Restarting plasmashell multiple times
a day is just not funny.

> I know, I know more than 90 % and all the 
> "lightweight" people get this wrong. But you know what I observed more 
> and more over the last years: people praise Plasma for the fast speed, 
> responsiveness and low memory consumption. Why is that so, why do people 
> no longer consider our software as bloated? Because we use QML and we 
> use it well!

For me it - sadly - got worse over time.

> So if that gets added I want to have it made clear that this is not a 
> "lightweight" product

Did you read "lightweight" anywhere in my README ?

> and I don't want it to be advertised as not using 
> hardware acceleration.
> I don't want to see what you list in the main 
> motivation.

I did not know that I need permission from you for what motivates me

> Because that will just result in people going all "KDE dev 
> develops new desktop shell, because Plasma is unreliable".

which it is for me, sorry

> If that happens it pisses me off! And that's what's going to happen the way you 
> phrased it. And what would piss me even more of is if that is due to you 
> misunderstanding hardware acceleration.

I removed now the "no hardware acceleration" sentence from my README, since I'm
obviously too dumb to know what I write, sorry.

To be clear:
It was not the "no hardware acceleration" need which led me starting liquidshell,
it was the troubles I had with plasmashell (and obviously with the hardware I'm using).
And since I'm using QtWidgets since ages and have no QML experience, this was clearly
the way to go for me.
Trying to debug plasmashell to find the reason for the troubles is a route I tried
for a short period, but simply gave up. I have no idea how I would debug a scene graph
and I know close to nothing about openGL - and I don't need to.
I'm pretty sure this would have taken much longer and was much less fun
than starting from scratch with a technology I know.

Best regards/Schöne Grüße

A: Because it breaks the logical sequence of discussion
Q: Why is top posting bad?

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