I want to emulate a dial input because skeuomorphism is cool. I thought it would be nice to freeze the mouse pointer while a dial is clicked so it doesn't wander off to the void while the user watches the dial value. Do you think this is a good idea? Also, is there any gui toolkit that allows this?

Why care about the mouse pointer? Users will hate you anyway for this shit.

You mean a rotating knob (or equivalent) sort of thing? Music production software have been doing that forever, the general trend is that you click and drag up to increase the value and drag down to decrease. Don't worry about the pointer going off, freezing it will feel unnatural.

I know dials on virtual GUIs are Bad(TM) but this is a game, and it being authentic is a lot more important than convenience. However once it's authentic, it could also be convenient, that's why I asked. I think I'll skip it for now anyway and just use what Qt has by default, maybe return to it later.