[Qt-interest] Widget does not update content after some time

[Damien R]

> Seeing two locks, I bet you have deadlock situation -- you've already
> acquired the lock in setImage(), then you invoke update. However, you
> still hold the lock. What happens if update() calls your paintEvent()
> method for the same object? You attempt to lock again, but you already
> hold the mutex. Deadlock.

No, it is not a deadlock. update() add an event in the process event list of
Qt so update() do not directly call paintEvent() as I understand the
documentation of Qt. So this code is never equivalent to the following code
:
void setImage(std::size_t i)
{
  boost::mutex::scoped_lock lock(mutex_);
  uchar * imageBuffer = image.bits();
  memset(imageBuffer, i * 25 % 255, WIDTH * HEIGHT * 3);
  paintEvent(0);
}

Moreover, the program is not frozen. Indeed, if I hide the widget and show
it again, the content of the widget is updated.

--
Damien R
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