Ticks & intervals

Value-axis tick density is driven by:

1. Space budget — how many labels physically fit
2. Nice intervals — candidates like 1, 2, 2.5, 5, 10 × powers of 10
3. Selection — prefer preferredTickInterval when allowed; otherwise aim for a sparse target label count (not the densest fit)

Sparse auto targeting

Space for (max labels)	Aim for
1–5	~2 labels
6–13	~3
14–20	~4
21+	~5

Preferred interval

axes: {
  left: {
    labels: {
      preferredTickInterval: 10,
      // customTickInterval is set by the engine when resolving
    },
  },
}

preferredTickInterval is a step size, not “number of labels.” Leave it null for new charts so auto sparse selection runs.