different widths in bar plot when using undropped factor levels

[bsgerber]

I found a potential problem with the widths of bars using geom_bar when using factor levels, and keeping unused levels with drop = F argument in scale_x_discrete. This can be overcome by setting the width in aesthetic but thought the variable nature of widths in plotting might be an issue.

Here is the code to reproduce the bug:

library(ggplot2)

df <- data.frame(
  x = factor(c('A', 'D'), levels = LETTERS[1:5])
)

ggplot(df, aes(x)) +
  geom_bar() +
  scale_x_discrete(drop = F)

df <- data.frame(
  x = factor(c('B', 'D'), levels = LETTERS[1:5])
)

ggplot(df, aes(x)) +
  geom_bar() +
  scale_x_discrete(drop = F)

^{Created on 2023-02-28 with reprex v2.0.2}

[teunbrand]

This is indeed unfortunate. Given that resolution(), which determines the default width, makes a special case for integers; should it also use that case for the "mapped_discrete" class? See:

ggplot2/R/utilities-resolution.r

Lines 21 to 22 in 5141ef5

	if (is.integer(x) || zero_range(range(x, na.rm = TRUE)))
	return(1)

[thomasp85]

Yes, I think that is sensible