This method will create a pixmap and a temporary QGLContext to render on it. Finally, the widget's original GL context is restored. The size of the pixmap will be width w and height h . If useContext is TRUE, this method will try to be more efficient by using the existing GL context to render the pixmap. Use only if you know what you are doing.
Handles resize events.
Reimplemented from QWidget. This virtual function is called whenever the widget has been resized. Reimplement it in a subclass. Turns on or off the automatic GL buffer swapping. The buffer auto-swapping is on by default.