Da fuck!? Waits for someone to patent controlling the volume of a device by moving a slider back and forth along a predefined path....
Probably wouldn't work out too well. Of course you could argue that you're doing it in software so it's different.
Oh wait, that's been done for ages now. Okay, let's just go one step further and pretend that doing it with touch gestures is novel enough for it to work.
Unless the first person to implement it filed for a patent several years ago, it'd be far too late to get one at this point. Perhaps it would be entirely possible to get a patent on something like this, but the first people to implement it didn't think it would be worth their time or that it wouldn't hold up in court. Who knows.