For what it's worth, I happen to have exactly this situation (fixed point, formatting, choice of rounding), and in this particular case I chose not to waste my time rounding since it truly doesn't matter:

```
                let temp = I9F7::from_bits(PPG_TEMP.load(Ordering::Relaxed));
                view.add(Item::String(-1, "Temp", view.string(|buf| write!(buf, "{}.{:02} C", // "°" is not in this font yet
                    u8::from_fixed(temp),
                    u8::from_fixed(temp.frac() * 100),
                ))));

```