Function nice_step

src/ticks.rs:142–155

Calculate a "nice" step size for grid lines based on the desired number of divisions. Returns a value that is a multiple of 1, 2, 5, or 10 times a power of 10.

(raw: f64)

    let start_exp = lo.log(base).ceil() as i32;
    let end_exp = hi.log(base).floor() as i32;
    if start_exp > end_exp {
        return Vec::new();
    }

    let max_ticks_for_spacing = (size_px / 30.0).ceil() + 1.0;
    let skip = ((end_exp - start_exp + 1) as f64 / max_ticks_for_spacing).ceil() as i32;

    let mut out = Vec::with_capacity((end_exp - start_exp + 1) as usize);
    for (i, exp) in (start_exp..=end_exp).enumerate() {
        if i as i32 % skip != 0 {
            continue;
        }

        let value = base.powi(exp);
        if value.is_finite() {
            out.push(Tick::new(value, base, TickWeight::Major));
        }