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

[Saul]

Hi all,
I try to get the output of my webcam with opencv and display it through qt. Therefore I convert the IplImage into a QImage and call the function setPixmap() to draw the image onto a QLabel. Afterwards I repaint the QLabel to update it. Generally the output works fine but the program isn't responsive to any command. I can't close it by push esc or clicking on the "X" to close the window. My last option is to break the program by "ctrl-alt-del".

Does anybody has a hint or know where the problem lie?
I would be very excited for any help.
Thanks in advance and kind regards,
Saul

Thats my whole code:

// main.cpp
 
#include "webcam.h"
#include <QtGui/QApplication>
 
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
Webcam w;
w.show();
return a.exec();
}

// main.cpp

#include "webcam.h"
#include <QtGui/QApplication>

int main(int argc, char *argv[])
{
QApplication a(argc, argv);
Webcam w;
w.show();
return a.exec();
}

To copy to clipboard, switch view to plain text mode 

// webcam.h
 
#ifndef WEBCAM_H
#define WEBCAM_H
 
#include <QtGui/QMainWindow>
#include "ui_webcam.h"
#include "cv.h"
#include "highgui.h"
 
class Webcam : public QMainWindow
{
	Q_OBJECT
 
public:
	Webcam(QWidget *parent = 0, Qt::WFlags flags = 0);
	~Webcam();
 
private:
	Ui::WebcamClass ui;
 
public slots:
	void showWebcam();
};
 
#endif // WEBCAM_H

// webcam.h

#ifndef WEBCAM_H
#define WEBCAM_H

#include <QtGui/QMainWindow>
#include "ui_webcam.h"
#include "cv.h"
#include "highgui.h"

class Webcam : public QMainWindow
{
	Q_OBJECT

public:
	Webcam(QWidget *parent = 0, Qt::WFlags flags = 0);
	~Webcam();

private:
	Ui::WebcamClass ui;

public slots:
	void showWebcam();
};

#endif // WEBCAM_H

To copy to clipboard, switch view to plain text mode 

// webcam.cpp
 
#include "webcam.h"
 
Webcam::Webcam(QWidget *parent, Qt::WFlags flags) : QMainWindow(parent, flags)
{
	ui.setupUi(this);
 
	connect(ui.actionStart, SIGNAL(triggered()), this, SLOT(showWebcam()));
}
 
Webcam::~Webcam() { }
 
void Webcam::showWebcam()
{
	IplImage *image;
	CvCapture *capture;
	capture = cvCaptureFromCAM(0);
 
	int esc = 0;
	while(true)
	{
		image = cvQueryFrame(capture);
 
		cvCvtColor(image, image,CV_BGR2RGB);
		QImage qimg((const uchar *)image->imageData, image->width, image->height, QImage::Format_RGB888);
		ui.label->setPixmap(QPixmap::fromImage(qimg));
		ui.label->repaint();
 
		esc = cvWaitKey(10);
		if (esc == 27) break;
	}
	cvReleaseCapture(&capture);
}

// webcam.cpp

#include "webcam.h"

Webcam::Webcam(QWidget *parent, Qt::WFlags flags) : QMainWindow(parent, flags)
{
	ui.setupUi(this);

	connect(ui.actionStart, SIGNAL(triggered()), this, SLOT(showWebcam()));
}

Webcam::~Webcam() { }

void Webcam::showWebcam()
{
	IplImage *image;
	CvCapture *capture;
	capture = cvCaptureFromCAM(0);

	int esc = 0;
	while(true)
	{
		image = cvQueryFrame(capture);

		cvCvtColor(image, image,CV_BGR2RGB);
		QImage qimg((const uchar *)image->imageData, image->width, image->height, QImage::Format_RGB888);
		ui.label->setPixmap(QPixmap::fromImage(qimg));
		ui.label->repaint();

		esc = cvWaitKey(10);
		if (esc == 27) break;
	}
	cvReleaseCapture(&capture);
}

To copy to clipboard, switch view to plain text mode