I've been exploring the QSystemTrayIcon on my Linux workstation and observed that the example I copied from the tutorials was not working properly. It turns out that the issue lies with the picture format of the icons. SVG icons are not rendering in my KDE 5 system tray whilst PNG icons do render.

It looks like this could be related to https://bugreports.qt.io/browse/QTBUG-44686 where the issue on OSX was that the SVG didn't have a native size to report. As Cedric writes:
> I have a patch that is working fine on my Mac See : https://bugreports.qt.io/secure/attachment/46918/qt5-svgicon-systray-osx.patch
> QIcon::availableSizes return nothing with SVG icons so we need to fix the correct size.
> QIcon::actualSize will take the ratio of the SVG image into account and will fix the size, we just need to give it the maximum size that is QSize(maxPixmapHeight, maxPixmapHeight).

My Version: https://github.com/richardeigenmann/QtSystray
Original: https://doc.qt.io/archives/4.6/desktop-systray.html