Comment by ErroneousBosh

When I got into developing audio plugins a while ago (wow, what, 20 years ago) the library I used had rotary knobs that needed a rotary mouse motion to control them, although it had the nice feature that if you clicked on the knob the further you dragged away the slower the knob moved.

Since then I've switched to a library where even with rotary knobs you drag up and down to adjust them, which seems easier for most folk.

The advantage that rotary knob widgets have is that they are compact and you can see instantly what the value is set to.

I wouldn't even consider a spinner. They're utterly contentless.