Displaying sequence of images from separate thread

  • Hi,

    I want to display a sequence of images with about 10-20fps using QLabel. Since the images are created by a separate thread, I use a signal/slot construction to avoid thread safety issues (see code below). All in all it works well, but some images get sporadically lost, i.e., they are not displayed. Adding a call to show() doesn't help. Any ideas what's going wrong? Thanks a lot in advance for your help and sorry if this is a newbie question!


    @class gui: public QWidget {
    void nextImage(QImage img);
    void signalImage(QImage img);
    public slots:
    void setImage(QImage img);
    QLabel *label;

    gui::gui() {
    label = new QLabel(...);
    QObject::connect(this, SIGNAL(signalImage(QImage)), this, SLOT(setImage(QImage)));

    void gui::nextImage(QImage img) {
    emit signalImage(img);

    void gui::setImage(QImage img) {
    // label->show();
    Main thread:
    @ gui myGui;@

    Application thread:
    @ QImage img(...);

  • Lifetime Qt Champion

    Hi and welcome to devnet,

    Your code seems a bit convoluted to to achieve what you want, maybe have a look at the "mandelbrot example":http://qt-project.org/doc/qt-4.8/threads-mandelbrot.html
    It explains a similar setup as yours (although the image generation will differ)

    Hope it helps

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