http://docs.opencv.org/3.1.0/dc/d46/group__highgui__qt.html#gac56ae86269eb4fbd9c8d8cb7babfbf64
http://docs.opencv.org/3.1.0/d7/dfc/group__highgui.html#ga5afdf8410934fd099df85c75b2e0888b
http://docs.opencv.org/3.1.0/df/d24/group__highgui__opengl.html#gaf80dcbc168a6ce40f6d1ad9d79a10bb8