SuperBuild Qt cannot find system's theme
I'm not quite sure what is wrong with QT theme, but something is fishy.
Using the SuperBuild (and therefore binary packages) on linux, otbgui apps are missing the system's theme and therefore have an ugly and non native look and feel. Apparently this is actually a known problem of QT5 on linux for example on Ubuntu it requires a user action, or see also the arch wiki.
However the workarounds I could try do not work for OTB SuperBuild because QT in OTB code does not even find the system's theme:
// call this inside otbApplicationLauncherQt.cxx for example qInfo() << "Available styles: " << QStyleFactory::keys().join(" "); >>> Available styles: "Windows Fusion"
I'm on Ubuntu so I should see "gtk2" in the list above. I'm able to force vlc for example to use the system's theme:
Steps to reproduce
Use the binary package or the SuperBuild on linux and try to force the system theme:
$ ./bin/otbgui_DynamicConvert -style gtk2 QApplication: invalid style override passed, ignoring it.
Ubuntu 18.04, Superbuild develop or standalone binary package 6.7.