Time from nanoseconds to centuries¶

A plot may span a microsecond of a CPU trace or a thousand years of history. anytimeline handles both with one rule.

One unit per plot¶

Times become whole numbers of one unit, chosen per plot: the coarsest of seconds, milliseconds, microseconds and nanoseconds that keeps every value exact. Millisecond log timestamps give milliseconds; a trace with nanoseconds gives nanoseconds. Each plot counts from its earliest event.

A 64-bit count of nanoseconds reaches only from 1677 to 2262, so dates outside that range are kept in microseconds, milliseconds or seconds: a count of seconds reaches hundreds of billions of years.

Precision in the browser¶

The graphics chip computes with 32-bit floats, which hold about 7 significant digits: over a day in nanoseconds, that is only about 5 ms. The browser therefore sends positions relative to a point near the view, and moves that point when you move far from it, so a mark lands on the right pixel at any zoom, down to a nanosecond. Tick labels are computed with exact integers, so they are exact anywhere.

Calendars and time zones¶

The time axis follows the calendar of the plot's time zone: hour ticks stay on the local clock, and a day with a daylight-saving change has 23 or 25 hours. Ticks run from nanoseconds (.000 000 110) through seconds, minutes, days, months and years to centuries; a second row above the ticks gives the context (the date of hour ticks, the second of sub-second ticks).