Show webcam through Qt - progam doesn't respond to any user input

[Saul]

Hi, its me again.
I just want to ask, if it's conform to use QCoreApplication:: processEvents(); directly in my loop? Or is it unsuitable to use it this way?
I'm a little bit self-conscious in this way, yet. Would be very thankful for a "Yes" or a "NO" =)

Are there any other possibilities to realize a webcam output?
Ok, the first one I tried is the QLabel. Think it could be done with Phonon::VideoPlayer, too.
Are there even more possibilities?
Kind regards,
Saul

[d_stranz]

It is OK to use QCoreApplication:: processEvents() in a loop.

On the other hand, if you are forced to do that in order to get a responsive application, it is generally a sign that your application design could be improved.

Usually, it is better to try to implement a signal / slot or multithreaded design so that compute-intensive work gets done in a different thread from the GUI, and communicates to the GUI thread using signals (something like "frameReady").

You might be able to use Phonon, but I am not familiar with it so someone else will have to answer that question.

[Saul]

OK, thanks again d_stranz!
I will do my best. Bought a Qt book and found a chapter about threads yesterday. Armed and ready for the fight now

But I have just one last Question and Problem. If I close the Program the webcam is still running. My function to break the loop by push the button ESC does not work.

[stampede]

I've posted a simple Qt + OpenCv example here, you may want to check it out. You don't need any separate threads or processEvents() calls to get responsive ui during webcam capture and simple image processing, just use QTimer.