title: Is it safe to draw three separate QImages in three separate QThreads?
body: <p>I have a QMainWindow with three widgets inside that are promoted to a class containing a subclassed QThread.  They each draw on a local QImage in their rexpective qthread which is sent with a signal once its drawn and then rendered by calling update (mandlebrot example) from the slot. Is this safe or dangerous? They do not share any data, at least none that I am generating and am wondering what data they could be sharing that is outside of my coding range ie that is generated by Qt automatically.</p>