Hi,
I'm developing the interface for an oscilloscope instrument; I would like to use knobs for gain and timescale selections, but the current knobs does not have the required capabilities.

I'm going to develop myself the required stuff, if needed, but before I write here to ask for suggestions.
I need a knob with only a set of predefined values in a wide scale range: lets say 1, 2 and 5 as fixed multiplier. I even would like that the scale labels were with the unit specified (as 5us, or 1mV).
Maybe I can create a my version of QwtRoundScaleDraw, to fix this last point, and I can write a specialized QwtLog10ScaleEngine for the 125 scale. But I need that the knob only selects values in the scale (1, 2 or 5 x scale factor).

Any idea?

Alessandro