《学习 OpenCV》第二章 26页练习

cvNamedWindow("Example3",CV_WINDOW_AUTOSIZE);
    g_capture = cvCreateFileCapture("d:\\cv.avi");
    int frames = (int) cvGetCaptureProperty(g_capture,CV_CAP_PROP_FRAME_COUNT);

    if(frames != 0)
    {
        cvCreateTrackbar("Position","Example3",&g_slider_position,frames,onTrackbarSlide);
    }
    IplImage *frame;
    while(1)
    {
        frame = cvQueryFrame(g_capture);

        if(!frame) break;

        cvShowImage("Example3",frame);
        cvSetTrackbarPos("Position","Example3", ++g_slider_position);
        char c = cvWaitKey(33);
        if(c == 27) break;
    }

    cvReleaseCapture(&g_capture);
    cvDestroyWindow("Example3");
    return 0;
}

void onTrackbarSlide(int pos)
{
    cvSetCaptureProperty(g_capture,CV_CAP_PROP_POS_FRAMES,pos);
}