How to get Aero Glass effect (transparency in window decorations) in KDE Plasma 5?

How can I enable an effect similar to Aero Glass in Windows for window’s titlebars without switching the default Breeze theme?

It can be done pretty easily in Unity/Compiz by gsettings altering metacity-theme-active-opacity and metacity-theme-inactive-opacity keys of the org.compiz.gwd schema. This will produce the titlebar effect looking like this:

Unity pic

In KDE4 this effect definitely existed also. This can be seen on screenshot found on Mint forums:

KDE pic

But KDE Plasma 5 hasn’t got Decorations slider in the options of the Translucency effect which can be found in System Settings > Desktop Behavior > Desktop Effects (I am using Ubuntu 16.04 with KDE Plasma v5.5.5).

I am aware that people somehow change the transparency of the panels by editing proper SVG files of the theme (though there’s a method which is more simple than that).

If you direct me which file(s) of the theme should be altered to gain titlebar transparency I’d also accept it as an answer, if no easier methods exist.

Asked By: whtyger


I’ve found how to get the transparent titlebars in Plasma. This setting is stored in color scheme file. As Plasma overwrites default scheme file on each start, it isn’t possible to alter Breeze color scheme directly. So let’s make a copy of the scheme and alter it instead:

cp ~/.kde/share/apps/color-schemes/Breeze.colors /tmp/BreezeMod

I renamed Breeze theme to BreezeMod (you can use any other name) and omitted ".colors" extension, because it will be added later automatically. Open BreezeMod file in any editor and find [WM] section in the end of the file.

Original parameters:

Modified parameters:

Each parameter represents color consisting of RGB components divided by commas. activeBackground sets titlebar’s color of active window, inactiveBackground sets titlebar’s color of inactive windows. I added fourth component, representing Alpha channel, which sets transparency. Its value lies within [0-255] interval, higher values mean less transparency. I used 208. I also changed inactiveForeground which sets the color of text on inactive titlebar. This step is optional, but when transparency becomes active, text blends with the titlebar and becomes unreadable, so I decreased all 3 components’ values by 100, shifting text color from gray to black.
Also update ColorScheme and Name parameters in [General] section to match your altered scheme name.
Now this theme should be activated. Open System Settings > Color, press Import Scheme... and open BreezeMod file, then press Apply. Here’s the result:

If you wish to change only inactive windows’ titlebars, leave activeBackground parameter intact and vice versa. If you wish to play with parameters, alter BreezeMod file and import scheme once again, overwriting the existing one.
Tested in 16.04 with Plasma 5.5.5.

Answered By: whtyger