Parametrize r_rescale

[KryeKuzhinieri]

We are facing issues to fill the blank space in pie charts using ggplot2_3.5.1 (issue in other versions too).

The following code:

library(ggplot2)

# Create Data
data <- data.frame(
  group=LETTERS[1:5],
  value=c(13,7,9,21,2)
)

# Basic piechart
ggplot(data, aes(x="", y=value, fill=group)) +
  geom_bar(stat="identity", width=1) +
  coord_polar("y", start=0) +
  theme_gray() +
  theme(
    panel.grid.major = element_blank(),
    panel.grid.minor = element_blank(),
    axis.text.x = element_blank(),
  )

Gives the following graph:

The issue seems to arise from the r_rescale function which has the donut = c(0, 0.4) hardcoded. This can be fixed by overriding the function as shown below:

library(scales)
library(ggplot2)

# Create Data
data <- data.frame(
  group=LETTERS[1:5],
  value=c(13,7,9,21,2)
)

custom_r_rescale <- function(x, range, donut = c(0, 0.49)) {
  x <- squish_infinite(x, range)
  rescale(x, donut, range)
}
assignInNamespace("r_rescale", custom_r_rescale, ns="ggplot2", pos="package:ggplot2")


ggplot(data, aes(x="", y=value, fill=group)) +
  geom_bar(stat="identity", width=1) +
  coord_polar("y", start=0) +
  theme_gray() +
  theme(
    panel.grid.major = element_blank(),
    panel.grid.minor = element_blank(),
    axis.text.x = element_blank(),
  )

However, this is a hacky way to solve this issue. It seems that the same issue was reported in a stackoverflow issue as well.

The question I have is if it would be possible to parametrize this parameter or this function?

Thanks a lot!

[teunbrand]

I don't think this will be implemented for coord_polar() as it has been superseded by coord_radial().
The reason there is extra space around the edge of the circular area is because it is a place reserved for axis labels.
For that reason, I wouldn't like (the option) to get rid of this space.

If you insist on ignoring the axis label space, you can override the relevant parameter in the coord like so:

# Add this to plot with `+`
  ggproto(
    NULL, coord_radial("y", start=0, expand = FALSE),
    inner_radius = c(0, 0.5)
  )