handle keyevent in multi-threading application with Qt+OpenCV
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I have a multi-threading application written in C++ with Qt5.7 and OpenNI. It has a main thread that starts a second thread which capture frame from a .oni recording file (asus xtion pro live) does some processing and through the Qt signal-slot mechanism pass the frame to the main thread, which display it using imshow(). What I want to do is to implement a pause key, so pressing for example 'p' the processing pause. I am thinking of something like this:
void Camera::run(){ while(!cameraStop && this->device.isValid()) { try { if (!buttonPause) { getFrame(); process(); emit sigFrameImageReady(frame); if (cv::waitKey(1)==112){ setButtonPause(!(getButtonPause())); } } } catch(std::exception &ex) { std::cerr << "getFrame()" << ex.what() << std::endl; } } }In this way it doesn't work, I think that's because the frame is displayed by another thread (the main one), the waitKey() here simply blocks the entire process, but if I put it in the main thread, just after imshow() in this way:
void Process::FrameImageReady(cv::Mat FrameImage) { if (modedebug) cv::imshow("bgr", FrameImage); if (cv::waitKey(10)==112){ cam->setButtonPause(!(getButtonPause())); } }waitkey seems to be ignored (image displaying works fine).. any idea? Perhaps it is better to use a Qt function do it ?
It is a console application, the GUI part is only for debugging purpose. -
I have a multi-threading application written in C++ with Qt5.7 and OpenNI. It has a main thread that starts a second thread which capture frame from a .oni recording file (asus xtion pro live) does some processing and through the Qt signal-slot mechanism pass the frame to the main thread, which display it using imshow(). What I want to do is to implement a pause key, so pressing for example 'p' the processing pause. I am thinking of something like this:
void Camera::run(){ while(!cameraStop && this->device.isValid()) { try { if (!buttonPause) { getFrame(); process(); emit sigFrameImageReady(frame); if (cv::waitKey(1)==112){ setButtonPause(!(getButtonPause())); } } } catch(std::exception &ex) { std::cerr << "getFrame()" << ex.what() << std::endl; } } }In this way it doesn't work, I think that's because the frame is displayed by another thread (the main one), the waitKey() here simply blocks the entire process, but if I put it in the main thread, just after imshow() in this way:
void Process::FrameImageReady(cv::Mat FrameImage) { if (modedebug) cv::imshow("bgr", FrameImage); if (cv::waitKey(10)==112){ cam->setButtonPause(!(getButtonPause())); } }waitkey seems to be ignored (image displaying works fine).. any idea? Perhaps it is better to use a Qt function do it ?
It is a console application, the GUI part is only for debugging purpose.
