QImage与OpenCV一起损坏

Question

我有一个Qt和OpenCV的网络摄像头演示。 基本上，它将显示网络摄像头的提要，并且当单击按钮时，它将以一个长线程（三十五秒）启动一个线程。

问题是，当我单击该按钮时，QImage 立即损坏， 正如您在此处看到的那样，并且不再看到视频源。 信号和插槽正常工作（我在控制台中看到了输出），但是在这里我无法发现问题。

有人可以帮忙吗？

window::window() : QMainWindow(NULL, 0)
{
    std::cout << "constructor start" << std::endl;

    setWindowTitle("Video");

    button = new QPushButton("Long Job");
    connect(button, SIGNAL(clicked()), this, SLOT(longjob()));

    image = new QLabel();
    image->setAlignment(Qt::AlignCenter);

    layout = new QVBoxLayout();
    layout->addWidget(image);
    layout->addWidget(button);

    mainwidget = new QWidget();
    mainwidget->setLayout(layout);

    resize(800, 600);

    setCentralWidget(mainwidget);

    cap = cv::VideoCapture(0);

    timer = new QTimer();
    timer->setInterval(100);
    timer->start();
    connect(timer, SIGNAL(timeout()), this, SLOT(newframe()));

    std::cout << "constructor end" << std::endl;
}

void window::newframe()
{
    std::cout << "FRAME " << count++ << std::endl;

    cv::Mat frame;
    cap >> frame;

    image->setPixmap(QPixmap::fromImage(showImage(frame))); // converts perfectly
}

void window::longjob()
{

    std::cout << "START THREAD" << std::endl;

    w = new worker();

    connect(w, SIGNAL(resultReady(double)), this, SLOT(detected(double)));

    w->start();

    return;
}

void window::detected(double d)
{
    disconnect(w, SIGNAL(resultReady(double)), this, SLOT(detected(double)));

    std::cout << "DETECTED " << d << std::endl;

    delete w;

    frames.clear();
}

class worker : public QThread
{
    Q_OBJECT

public:

    worker();

    ~worker();

    void run() Q_DECL_OVERRIDE;

signals:
    void resultReady(double d);
};

worker::worker() : QThread()
{

}

worker::~worker()
{
    std::cout << "THREAD EXIT" << std::endl;
}

void worker::run()  
{
    std::cout << "THREAD RUN" << std::endl;

    double d = longOpenCVJob();

    emit resultReady(d);
}

Answer 1

答案来自Evgeniy：QImage不拥有数据，也不像该答案所示那样模仿STL容器。

Answer 2

我会将这段代码用于showImage（）：

QImage window::showImage(cv::Mat mat)
{
  cv::Mat tmp;
  mat.convertTo(tmp, CV_8U);
  cvtColor(tmp, tmp, CV_BGR2RGB);
  QImage img = QImage((const unsigned char *)(tmp.data), tmp.cols, tmp.rows, tmp.step, QImage::Format_RGB888);
  return img;
}