Add suppport for KDE/Plasma

[maxanier]

On my linux system with Plasma (running Arch Linux/Manjaro) this tool does not work since neither gsettings nor gconftool-2 nor dcop work even though they are present.

This PR adds a working method using qdbus.

Without #27 or similar this does not really help as the other ones (gsettings ...) are present and used first.
As a workaround I just manually delete all other services from the lib/linux.js script for now.

[sindresorhus]

Use a template literal here for the code and format it properly, for readability reasons.

[sindresorhus]

What JS engine and version is PlasmaShell running?

[maxanier]

Not sure what you mean with template literal here (haven't worked much with JS).
Also don't know much about the JS engine.
Just wanted to share my solution here after I managed to find/create a working command.

[sindresorhus]

https://www.google.co.th/search?q=javascript+template+literal&oq=javascript+template+literal&aqs=chrome..69i57j0l5.7768j0j1&sourceid=chrome&ie=UTF-8

[maxanier]

I found them of course :D Just not sure how to apply them here.
Just use the multiline (without \n) functionality like follows or do some magic tricks with replacement and more?

set: ['org.kde.plasmashell',
		'/PlasmaShell',
		'org.kde.PlasmaShell.evaluateScript',
		`var allDesktops = desktops();
		//print (allDesktops);
		for (i=0;i<allDesktops.length;i++) {
		d = allDesktops[i];
		d.wallpaperPlugin = "org.kde.image";
		d.currentConfigGroup = Array("Wallpaper", "org.kde.image", "General");
		d.writeConfig("Image", "file://%s");
		}` ]

[sindresorhus]

That's what I was thinking, yes.

[sindresorhus]

this does not really help as the other ones (gsettings ...) are present and used first.

Can't we just change the order to prefer this if available over gsettings?

[maxanier]

I think qdbus is available on (at least some) other systems (not running Plasma) as well, so it would be used instead of gsettings and thereby break the functionality.

[sindresorhus]

We could detect if Plasma is installed then.

[sindresorhus]

I did some formatting tweaks. Can you confirm it still works?

[maxanier]

Yes, we could check for plasmashell for example. However, this would of course require a modification of the program structure as it currently checks the cmd for availability. So we have to add an additional check for an optional command.

As this probably affects other desktops as well I suggest doing this separate from this PR.

Will check your changes when I am home

[maxanier]

Works