fn sweep_refresh(st: &mut StripeState, d: &mut HwFrameDecision, qp: u32)Expand description
A refresh due on a session that sweeps it (decide_hw_fullframe’s sweeps): a sweep from the
top, or, with one under way, which is already refreshing the picture, nothing held, the frame
going at the rate control’s quality: a sweep started over at every change of a blinking caret
would never cover the picture, and a whole held frame is what the sweep spreads.