1) Do not call Video::paint() with a scale != 1:1
2) For this reason we need to draw elsewhere
3) and finally scale the whole thing just once to the widget
4) QPixmap vs QImage: cant see the difference
5) QOpenGLWidget is 2x faster than QWidget but it has some flickering when resizing
On my i5-4460 CPU @ 3.20GHz with x2 zoom
TEXT: 4-5% CPU usage
HGR: 6-7% CPU usage
Signed-off-by: Andrea Odetti <mariofutire@gmail.com>
