Radial scale for periodic Kodom plots — scale_y_kodom

In coord_polar(theta = "x"), ggplot2 sets the center of the plot to the minimum data y value, not to zero. Because geom_kodom_periodic() stores the hollow-center gap as an offset above zero (inner_fraction * n_lanes), the gap is invisible without this scale: the auto-range simply absorbs it.

Usage

scale_y_kodom_periodic(expand = ggplot2::expansion(mult = c(0, 0.05)))

Arguments

expand: Passed to ggplot2::scale_y_continuous(). Default adds 5% padding beyond the outermost ring and no padding at the center.

Value

A ggplot2::scale_y_continuous() object.

Details

This function pins y = 0 at the center by setting limits = c(0, NA), so the offset computed by inner_fraction becomes a visible donut hole. It should be added to every plot that uses geom_kodom_periodic().

Examples

# \donttest{
library(ggplot2)
df <- data.frame(
  subject_id = rep(1:5, each = 4),
  time = rep(1:4, 5),
  visit_month = rep(1:4, 5),
  value = rep(1:4, 5),
  hba1c = rep(1:4, 5),
  arm = rep(c("Treatment", "Control"), c(12, 8))
)
ggplot(df, aes(x = visit_month, id = subject_id, colour = hba1c)) +
  geom_kodom_periodic(period = 12, inner_fraction = 0.3) +
  scale_x_continuous(breaks = 0:11, labels = month.abb) +
  scale_y_kodom_periodic() +
  scale_colour_kodom() +
  coord_kodom_periodic() +
  theme_kodom_periodic()

# }