How to take Screenshot of QML application without QQuickView

Question

I want to grab screen of my QML application. But my root QML object is ApplicationWindow, so I can\'t use QQuickView to show it. Instead I have to use

Answer 1

You can use the QObject *obj, QEvent *ev to take screenshot as well.

Main.cpp

QObject *objekt = engine.rootObjects().first();
classObj->root_object = objekt;
app.installEventFilter(classObj);

classObj.h

QObject *root_object = nullptr;
bool eventFilter(QObject *obj, QEvent *ev);

classObj.cpp

bool classObj::eventFilter(QObject *obj, QEvent *ev)
{
    QString dateInterval = QString::number(QDateTime::currentSecsSinceEpoch());

    QDir dir("Screenshots");
    if(!dir.exists())
        dir.mkpath(".");

    if(ev->type() == QEvent::MouseButtonPress) {
        QQuickWindow *window   = qobject_cast<QQuickWindow *>(root_object);
        window->grabWindow().save("Screenshots/Screenshot-"+dateInterval+".png");
    }
    return QObject::eventFilter(obj, ev);
}

this will take screenshot whenever some event happenes.

Answer 2

You can cast ApplicationWindow(QML) to QQuickWindow(C++). Then, It will be easy to take screenshot.

void ScreenShot(QQuickWindow *widget) {
    QPixmap pixmap = QPixmap::fromImage(widget->grabWindow());
    QFile f("your_name.png");
    f.open(QIODevice::WriteOnly);
    if(f.isOpen()) {
        pixmap.save(&f, "PNG");
    }

Answer 3

You can use rootObjects() and cast its result to QQuickWindow:

foreach(QObject* obj, engine.rootObjects()) {
  QQuickWindow* window = qobject_cast<QQuickWindow*>(obj);
  if (window) {
    QImage image = window->grabWindow();
    qDebug() << image;
  }
}