Range start, seconds.
Range end, seconds.
Width of the axis, CSS pixels.
Width of a label in CSS pixels, in the tick font.
preferredSpacingPx (default 70), minTicks (default 4) and
gapPx, the least space between two labels (default 12).
The ticks, as from timeAxisTicks.
Picks time ticks for an axis
widthPxwide.Starts from about one tick per
preferredSpacingPx. When that gives fewer thanminTicksticks (a narrow plot, where the 1-2-5 rounding can leave only the two ends), it tries denser steps and keeps the densest one whose labels still fit between neighbouring ticks withgapPxto spare, stopping onceminTicksis reached. Labels never overlap: a denser step is used only if its widest label fits.