How to apply absolute scaling to QGraphicsItems?

[hellozee]

Currently I am using a QTransform for scaling the items but since my items are resized by the mouse, the results looks awkward when multiple items are selected and then resized. So I wanted to scale the items with absolute scaling, but there seems to be no way to apply absolute scaling for all the items, though for some items like QGraphicsRectItem, it can be done by setting the corners.