Round an axis maximum up to a "nice" value

Picks the smallest multiple of unit that is greater than or equal to max(x). This reproduces the dynamic y-axis trick used throughout the original survey reports, where bar charts are given a tidy ceiling in units of 25 (percentages) or 5 (NPS counts) so that data labels never collide with the top of the panel.

Usage

nice_max(x, unit = 25, pad = 0)

Arguments

x: A numeric vector. NA values are ignored.
unit: Size of the rounding step (e.g. 25 for percentages, 5 for smaller counts). Must be a positive number.
pad: Extra headroom added to the result, in the same units as x. Useful to leave space for annotations above the tallest bar. Defaults to 0.

Value

A single numeric value: the padded, rounded-up ceiling. Returns NA if x is empty or all NA.

Details

The ceiling is (floor(max(x) / unit) + 1) * unit + pad: the next multiple of unit strictly above max(x), always leaving headroom even when the max already sits exactly on a multiple (e.g. nice_max(75) is 100, not 75). Use pad for additional headroom on top of that, e.g. for annotations above the tallest bar. An all-NA logical column (a common shape for an empty survey field) is tolerated and returns NA. This is the engine behind scale_y_pct() and the percentage plot wrappers, which is why their bars never quite touch the top of the panel.

Examples

nice_max(c(12, 63, 40))
#> [1] 75

nice_max(80, unit = 25)        # already need >75, so jumps to 100
#> [1] 100

nice_max(75, unit = 25)        # exact multiple still advances, for headroom
#> [1] 100

nice_max(c(8, 17), unit = 5, pad = 10)   # next multiple of 5 (20) + 10
#> [1] 30