`geom_function` does not produce a x axis title where no data is added

[davidhodge931]

library(tidyverse)

p <- ggplot() +
  geom_function(
    fun = \(x) dnorm(x),
  )

#currently produces this
p

#I think it should produce this
p +
  labs(x = "x")

^{Created on 2024-01-16 with reprex v2.1.0}

[teunbrand]

I think this is intended behaviour: as there is no variable that maps to the x aesthetic, there is no label to deduce from the way the plot is setup.

[davidhodge931]

But there is no y aesthetic, but that axis gets a title?? It doesn't seem consistent

[teunbrand]

The y aesthetic is a mapping in StatFunction$default_aes, which is why it gets a title.

[davidhodge931]

A function graph is used to show how x relates to y. So I think regardless of the internals that it should have a title

[teunbrand]

I think the required change would be in this line:

ggplot2/R/stat-function.R

Line 53 in a4be39d

default_aes = aes(y = after_scale(y)),

We may just add x = NULL to have x automatically pop up as the default label.