Adding KDE Neon To Ubuntu Zesty

If you have to do a fresh install and want to start from the standard Ubuntu Desktop (using Unity on zesty) as a base and then add KDE Neon (user, dev/stable or dev/unstable) then this hint may help. Assuming you have a /etc/apt/sources.list something like this below, where “zesty” could be artful (17.10) or bionic (18.04)…

deb http://archive.ubuntu.com/ubuntu zesty main universe multiverse restricted
deb http://archive.ubuntu.com/ubuntu zesty-updates main universe multiverse restricted
deb http://archive.ubuntu.com/ubuntu zesty-backports main universe multiverse restricted
deb http://security.ubuntu.com/ubuntu zesty-security main universe multiverse restricted
deb http://archive.canonical.com/ubuntu zesty partner # for adobe-flashplugin

deb http://archive.ubuntu.com/ubuntu xenial main universe multiverse restricted
deb http://archive.neon.kde.org/dev/stable xenial main

and have done an apt update && apt full-upgrade. The two xenial lines do not seem to interferre with the main zesty packages and allow the correct Neon dependencies to be installed…

apt install neon-desktop

should be all that is needed to get KDE Neon on top of Ubuntu Unity. However, installing Plasma will also bring in the sddm login manager and that will fight with the stock Ubuntu lightdm login manager. I did not have any success trying to get Ubuntu Unity to work with sddm so, for now, it looks like one has to disable sddm and rely on lightdm to switch between both desktops…

sudo systemctl disable sddm
sudo dpkg-reconfigure lightdm # and select lightdm

One other gotcha I noticed is that the Unity system settings are mostly missing and after reinstalling the unity-control-center I ended up with some strange non-HiDPI bunch of settings without icons and have yet to find to how to fix that particular problem. Seeing as I rarely expect to use Unity it’s in the realm of annoyance and not a show-stopper.

This strategy provides a very stable Ubuntu base system with all the Gnome/GTK libraries already installed for non-KDE apps and the opportunity to switch to the Unity desktop if need be.

One thing I noticed about Unity under zesty is that it detected and handled my QHD HiDPI (3200×1800) desktop without any manual configuration whereas under KDE Neon Plasma I have to set the font DPI to 232 and also twiddle with either the icon sizes or set up a 2.2 or 2.4 times zoom for the QHD screen.

Update: Using the zoom function causes some visual bloat so I’ve gone back to only increasing the size of the icons on a plasma-desktop and leave the zoom alone. It’s visually “tighter” with less space around some desktop components yet the icons are still usable… ie; 48px in the main toolbars and 128px for desktop, panel and dialog icons.

When the first 17.10 alpha comes out I will “upgrade” from zesty to artful and hope the xenial based Neon dev/stable desktop strategy keeps working. One thing I notice is that lightdm seems to be getting some wayland love already so by October 2017 I expect we should be able to run a dual Gnome and KDE (hopefully Neon) desktops side by side under Wayland instead of the Xorg display server.