Get spinbox cursor position

I am trying to make a QDoubleSpinBox that behaves as a Numerical Control in LabVIEW would.

Allow me to explain: In the LabView UI, the amount to increment/decrement is dependent on the position of the cursor. Consider a value of "10.2". If the cursor is on the decimal 2, then an incremental step would be 0.1; if it was on the 0 the value would be incremented by 1; and finally if the cursor position was on the 10, the value would be incremented by 10.

If this behavior were added to QT, the most logical place for it would be perhaps the stepType property of the QDoubleSpinBox, but that would require someone to create a new stepType for the spinbox, and I am not qualified to do that.
However, I feel confident of my ability to achieve this if the cursor position inside the spinbox would be available to me. So that is the background of my feature request.