Problem description:
When I use the Task Switcher in the large icon style in KDE plasma, the Emacs icon is always displayed in low resolution, like in the link below.
Steps to reproduce:
1. Install Emacs on Manjaro KDE edition
2. Use the Plasma Large Icons style for the Task Switcher (System Settings > Window Management > Task Switcher > Main Window > Visualization > Large icons)
4. Hit alt-tab
Actual results:
The alt-tab window switcher displays Emacs's icon as an ugly scaled-up 48x48 icon as shown in the above picture link.
Expected results:
The 128x128 icon should be used instead, so that the large icon is pretty and not pixelated.
The problem occurs because Emacs does not set _NET_WM_ICON_NAME to a 128x128 icon. Because of this, the window manager it not aware of the high-res icon, and is forced to display a scaled-up version of the largest icon it is aware of--the 48x48 version. This can be verified by running `xprop` and targeting Emacs's main window; you will see that the largest icon it knows about is only 48x48.
For more information and context, see the following:
https://bugs.kde.org/show_bug.cgi?id=351055https://specifications.freedesktop.org/wm-spec/1.4/ar01s05.html
The same problem have been discussed several times in the reddit, see:
