Sets the default breaks for a time axis

Source: R/xgx_breaks_time.R

xgx_breaks_time sets the default breaks for a time axis, given the units of the data and the units of the plot. It is inspired by scales::extended_breaks

xgx_breaks_time(data_range, units_plot, number_breaks = 5)

Arguments

data_range

range of the data

units_plot

units to use in the plot

number_breaks

number of breaks to aim for (default is 5)

Value

numeric vector of breaks

Details

for the extended breaks function, weights is a set of 4 weights for

  1. simplicity - how early in the Q order are you

  2. coverage - labelings that don't extend outside the data: range(data) / range(labels)

  3. density (previously granularity) - how close to the number of ticks do you get (default is 5)

  4. legibility - has to do with fontsize and formatting to prevent label overlap

References

Talbot, Justin, Sharon Lin, and Pat Hanrahan. "An extension of Wilkinson’s algorithm for positioning tick labels on axes." IEEE Transactions on visualization and computer graphics 16.6 (2010): 1036-1043.

Examples

xgx_breaks_time(c(0, 5), "hour")
#> [1] 0.0 0.6 1.2 1.8 2.4 3.0 3.6 4.2 4.8
xgx_breaks_time(c(0, 6), "hour")
#>  [1] 0.0 0.6 1.2 1.8 2.4 3.0 3.6 4.2 4.8 5.4 6.0
xgx_breaks_time(c(-3, 5), "hour")
#> [1] -3  0  3  6
xgx_breaks_time(c(0, 24), "hour")
#> [1]  0  3  6  9 12 15 18 21 24
xgx_breaks_time(c(0, 12), "hour")
#> [1]  0  3  6  9 12
xgx_breaks_time(c(1, 4), "day")
#> [1] 1 2 3 4
xgx_breaks_time(c(1, 12), "day")
#> [1]  0  3  6  9 12
xgx_breaks_time(c(1, 14), "day")
#> [1]  0  7 14
xgx_breaks_time(c(1, 50), "day")
#> [1]  0  7 14 21 28 35 42 49
xgx_breaks_time(c(1000, 3000), "day")
#> [1] 1080 1440 1800 2160 2520 2880
xgx_breaks_time(c(-21, 100), "day")
#> [1] -30   0  30  60  90
xgx_breaks_time(c(-1, 10), "week")
#> [1]  0  2  4  6  8 10