You've misread me--I'm suggesting to use the angle formed between vertical and the mouse's current position, and then wherever it moves, to add to the current position of the rotary knob.
This doesn't mean that you end up with having to carefully dial the knob, but it does let you click and drag the mouse in such a way that the rotary dial at least rotates in the direction you'd expect. The current behavior sometimes turns CW, sometimes CCW, seemingly at random--if we decide to skeuomorph, we might as well skeumorph correctly.
This doesn't mean that you end up with having to carefully dial the knob, but it does let you click and drag the mouse in such a way that the rotary dial at least rotates in the direction you'd expect. The current behavior sometimes turns CW, sometimes CCW, seemingly at random--if we decide to skeuomorph, we might as well skeumorph correctly.