Remove ggplot2 default padding

ggplot2 pads both continuous and discrete axes with a little expansion, which can make a taichi grid look like it is floating. remove_padding() trims that space. Called with no arguments it inspects the plot it is added to and figures out for itself whether each axis is continuous or discrete; pass "c" (continuous) or "d" (discrete) explicitly to override the detection, e.g. when the axis mapping is a computed expression the plot data cannot answer for.

Usage

remove_padding(x = NULL, y = NULL, ...)

Arguments

x, y

NULL (the default) to auto-detect the scale type of that axis from the plot's data and mapping, "c" for a continuous axis, or "d" for a discrete one. Auto-detection reads the plot's mapping, so name the type explicitly when x / y are mapped in a layer rather than in ggplot(), or when the mapping is a computed expression the plot data cannot answer for.

...

Additional arguments passed on to the underlying ggplot2::scale_x_continuous() / ggplot2::scale_x_discrete() (and y) calls. They go to both scales, so when the two axes are of different types only arguments that continuous and discrete scales share (name, breaks, labels, guide, ...) can be used here — a continuous-only argument such as n.breaks would be rejected by the discrete scale with an "unused argument" error. For per-axis options, add your own scale_x_*(expand = c(0, 0)) call instead.

Value

An object that, added to a ggplot, replaces both position scales with padding-free ones.

Examples

library(ggplot2)
d <- data.frame(x = 1:3, y = c("a", "b", "c"), yin = 1:3, yang = 3:1)

# auto-detects x as continuous and y as discrete
ggplot(d, aes(x, y)) +
  geom_taichi(yin = yin, yang = yang) +
  remove_padding()


# explicit override, identical result here
ggplot(d, aes(x, y)) +
  geom_taichi(yin = yin, yang = yang) +
  remove_padding(x = "c", y = "d")