c++ - 如何使用 Qt Camera 放大/缩小？

Question

我是 Qt 的新手，我必须在 Qt 中通过网络摄像头创建图像捕获并打印它。我已经设法完成了大部分需要执行的任务，但有一个问题，当我看到网络摄像头图像时，我想放大/缩小以捕捉图像，我该怎么做？我没有任何喜悦地搜索了网络。到目前为止我所拥有的

    ui->setupUi(this);
    vCam = new QCamera(this);
    vCamViewfinder = new QCameraViewfinder(this);
    vCamImageCapture = new QCameraImageCapture(vCam, this);
    vLayout = new QVBoxLayout;
    vMenu = new QMenu("Options",this);
    vStart = new QAction("Start", this);
    vEnd = new QAction("End",this);
    vCapture = new QAction("Capture",this);

    vMenu->addActions({ vStart, vEnd, vCapture });
    ui->pushButton_camAction->setMenu(vMenu);
    vCam->setViewfinder(vCamViewfinder);
    vLayout->addWidget(vCamViewfinder);
    vLayout->setMargin(0);
    ui->graphicsView->setLayout(vLayout);

    connect(vStart, &QAction::triggered, [&](){
        vCam->start();
    });
    connect(vEnd, &QAction::triggered, [&](){
        vCam->stop();
    });
    connect(vCapture, &QAction::triggered, [&](){
       on_pushButton_camAction_clicked();
    });

   void VisitorSignIn::on_pushButton_camAction_clicked()
    {
        QString vImage = "C:/Qt/VisitorsImages/1.jpg";
        vCamImageCapture->setCaptureDestination(QCameraImageCapture::CaptureToFile);
        QImageEncoderSettings imgEncSet;
        imgEncSet.setCodec("image/jpeg");
        imgEncSet.setResolution(640, 480);
        vCamImageCapture->setEncodingSettings(imgEncSet);
        vCam->setCaptureMode(QCamera::CaptureStillImage);
        vCam->start();
        vCam->searchAndLock();
        vCamImageCapture->capture(vImage);
        vCam->unlock();
    }  

Answer 1

看看http://doc.qt.io/qt-5/qcamerafocus.html这些方法允许光学和数字变焦。