@SGaist i did, it runs smooth with one camera, since its using available picture to stream, problem is when we have more than one camera, i cant choose each stream directly to communicate with in Qt. lets say i have a class in python that each def() does one job with a camera, one for focusing on for taking a picture one for sending too AI model and so on, i need to make 6 different object from this class for 6 different cameras and connect them to buttons in Qml, what i explained is alright, but the only part i can not do is the live stream for each camera separately, there is no function or at least i couldn't find which define separate stream of images for separate windows in qml, there are two method so far which looks for available stream of image not a specific one, one is imageprovider, other is paintclass this is were i have the main problem

You should: provide a clean way to quit your thread use a cleaner setup/tear down for the opening and closing of your device why all these sleep call ?

Hi and welcome to devnet, You do not have a constructor without argument.

What was the issue ?

@JonB Yes, you are right. converting Qt.Checked/Unchecked to int() to make it work in PySide6.3.1. Thank you @SGaist @CristianMaureira @JonB !! Problem solved.

I found the problem. The problem is that I update labels in show_gaze_information. This function is a callback that is called when a message is published on the topic. To correct the code, in function show_gaze_information, the message should be stored in a variable. Nothing should be modified in UI. Then in main body of code, I added this part: # update gaze infor periodically timer_gaze = QtCore.QTimer() timer_gaze.timeout.connect(update_gaze_information) timer_gaze.setInterval(500) timer_gaze.start() This code periodically calls update_gaze_information every 0.5 seconds. Now, in this function, I update labels in the UI.

@jsulm My UI freezes when I press the button that goes to 'qthread_test' in that code snippet. It starts to buffer and becomes unresponsive for a bit. That is the code sample that caused it. Yes there rare other elemetns in my code, but they do not connect ao any parts of this, it is mostly other elements like buttons. variables, etc.

So the one that creates a file is working but the one that changes a GUI element freezes ? Do I get you correctly ?

@CristianMaureira please find link to my plotting code link .

I tested your sample code with a conda environment, latest PyQt5, pyglet from pip and while the text is not properly placed, it's rendered correctly.

@JonB Thank you for this, it helped me solve my issues!

This is a different issue that should have it's own thread as it's not related to the problem at hand. You should also mark this thread as solved.

@Pythonic-person said in Zooming in/out QGraphicsView: And that won't affect the performance of the app or any other effect? LOL no. If anything I think it might be a microsecond faster. For all the QGraphicsItems on your scene it has to see where they are, who's on top of whom, whether the item is hidden, how to draw it etc. The foreground is just a simple layer it puts on top of any items (just as the background is below any items). There are probably lots of calculations it can skip, at a guess. If you want you can optimize the foreground/background redrawing with clip areas. Using the background/foreground of the scene or view for things which are static and not the actual objects you are playing with on the scene seems to me to keep things cleaner. E.g. if you go looking for one of your items on the scene, why do you want to have to encounter and skip a ruler or the background grid pattern or whatever?