/**
 * The gridline VALUES a magnitude axis prints — the "nice" round numbers under
 * the largest bar, chosen so the axis lands on about five of them.
 *
 * The rule belongs to the axis rather than to one chart, and it has one clause
 * that is easy to miss: **an axis over whole things has no half.** A count of
 * vehicles, contracts, trips or people cannot be 0,5, so a step finer than 1
 * prints gridlines at quantities the data can never take — and it happens
 * exactly where the numbers are smallest, because a max of 2 is where a
 * five-tick target starts reaching below the unit. The reader is then asked to
 * read "one and a half contracts", and the axis has stated something false
 * about the subject rather than about the layout. So the candidate steps are
 * filtered by what the DATA is made of: all-integer values take integer steps.
 */
export declare function axisTicks(values: number[]): number[];