Comment by nine_k
2 days ago
The problem of the knob is that it offers a large and precise control, but that large control remains invisible. There's no obvious clue showing that you can still interact with the knob by dragging the pointer / finger far away from it.
Adding a simple visual clue would help discoverablility a lot. Draw a faint halo on touch, when the mode changes. Draw a more visible trail when the touch point is dragged. Provide immediate and localized feedback, like good UX guidelines suggest.
Exactly. Based on this thing's depiction as a knob, every user is going to assume that you have to describe a ring around it by dragging the cursor in a circle... a fussy and awkward pain in the ass.