I need to flash some images with very precise timing (order of milliseconds) for which I developed a subclass of QGLwidget. The images are loaded as textures at initialization. I am using a QTimer instance to change the image being displayed. The timer's timeOut signal is connected to a timeOutSlot which does some file I/O and then calls updateGL().
While I understand that event handlers are for external events and signal/slot is for communication internal to the GUI, I could also implement this as a timeOutEvent handler.
Is there any performance difference between the two? Any performance penalty above 2-3 milliseconds is important to me (hardware is average, say Intel core 2 duo T5700 with nVidia 8600M GT graphics card).
I would say signal/slot because events are added to an event queue where Qt often does call optimisations and importance ordering, whilst s/s are executed immediately - albeit slower than direct calls.