tut_linecrossing_main.cpp

int main()
{
    Mat image = Mat::zeros(768, 1024, CV_8UC3);
    Canvas c("Counting People", image.size());
    c.enableScreenText();

    help(c);

    c.enableStatusMsg();

    c.setShapeType(LineCrossing::type); // default shape type for direct GUI creation

    namedWindow("Counting People", WINDOW_AUTOSIZE);
    c.setMouseCallback(); // optional for mouse usage see also (example_selectbox.cpp)

    TrackerSimulator tracker(c);
    auto buttonAlignment = VerticalLayout::create(c);
    buttonAlignment->setStretchXToParent(true);
    auto button = Button::create(*buttonAlignment,
                                 Point(image.cols / 2, 0),
                                 "Start / Stop\nSimulation",
                                 "", [&tracker](Widget *w)
    {
            tracker.setSimulatorOn(! tracker.getSimulatorOn());
    });
    button->setLayoutAnchor(Widget::CENTER);

    int minStepsPerSeconds = min(image.cols / 2, image.rows / 2) / 10;
    int maxStepsPerSeconds = max(image.cols / 2, image.rows / 2) / 10;
    Point center(image.cols / 2, image.rows / 2);
    int key = 0;
    Mat out;
    int fps = 25;
    int delay = 1000 / fps;
    do
    {
        tracker.simulate(2, center, 50, minStepsPerSeconds, maxStepsPerSeconds);
        switch (key)
        {
        case 'h':
            help(c);
            break;
        case 's':
            c.writeShapesToFile("line-crossings.xml");
            break;
        case 'l':
            c.readShapesFromFile("line-crossings.xml");
            break;
        case 65535:
            c.deleteActive();
            break;
        }

        c.redrawOn(image, out);
        c.imshow(out);
        key = c.waitKeyEx(delay); // GUI and callbacks happen here
    } while (key != 'q');

    destroyAllWindows();

    c.clearShapes(); // workaround for v1.0.0
    return 0;
}