How to get aggregated scaling factor for QML items?

[Asperamanca]

The effect of "scaling" a QML item aggregates, i.e. if an item's parent is scaled to 200 %, the item will also appear at 200 % scale.
Is there an easy way to get the aggregated scaling factor for an item?

Use case: My item opens a popup. The popup should use the same scaling as the item. Since the popup does not belong into the same item tree, it does not "inherit" the scaling automatically.

[GrecKo]

Can you assume only the direct parent will have its scale set and bind the popup's scale to it?
If you instead need to support a recursive item tree you could do it like that:

property real aggregatedScale: {
    let parent = popup.parent;
    let scale = 1;
    while (parent) {
        scale *= parent.scale;
        parent = parent.parent;
   }
   return scale;
}

[Asperamanca]

Thanks for your reply. I should have been more specific in my question: I know how to write it myself, I was looking for an existing function that already gives the that, akin to QGraphicsItem::sceneTransform.

Because how would you expose such a function to QML, so you have it available globally, for all items? I guess that would mean something like a singleton object.