Qt QML : GrabToImage functionality possible with QMLTemplate

Question

I am working with a Qt QML project. In that I need to take create some images during process. The actual image creation and storage should take places in background.

For this I have a qml template file as shown below

import QtQuick 2.0

Item {
    id:area
    width:960
    height: 960
    visible: true

    Image {
      id: name
      source: "file.jpg"
      anchors.fill: parent
    }

    StudentDetails
   {
      anchors.centerIn: parent
   }

}

And I want to render some details from cpp function to this QML file. i.e I want to update some student details from data base and render to this qml and store as image. For that I tried all the below methods.

// Using QQmlComponent
QQmlEngine engine;
QQmlComponent component(&engine,
    QUrl::fromLocalFile("MyItem.qml"));
QObject *object = component.create();
object->grabToImage(function(resut){result.saToFile("Stud01.png");}, Qt.size(960, 960));

Actually , this grabToImage call is not working here. This is just a qml template and I am not going to load this qml. just update some stud details and store as image. I also tried to call a function in qml and that qml file inside handling the grab image call.

But in both cases its not working. I am getting error like, Item::GrabToImage will not working since it is not attached to a window.

Can I do it? Can't I save an image from QML template. Is there any other way to save the qml as image.