I don't work on embedded platforms, but it seems Qt5 supports directfb, which can do windowing.
http://doc.qt.io/qt-5/embedded-linux.html http://stackoverflow.com/a/21489384/331041
http://doc.qt.io/qt-5/embedded-linux.html http://stackoverflow.com/a/21489384/331041
That's my understanding at least, I don't use Qt on embedded platforms though, can anyone confirm this?