Unexpected results using `guides(x = guide_axis(position = ...))`

[jtlandis]

When attempting to change the axis position with guide_axis it seems that the title is not correctly pulled unless manually specified.

library(ggplot2)

p <- ggplot(iris, aes(Sepal.Width, Sepal.Length, color = Species)) +
  geom_point() 

Currently you can swap the placement with scale_(x|y)_*(postion = ...) pretty reliably

p + scale_x_continuous(position = "top")

But trying to swap scales with guides() doesn’t seem to include the title

p + guides(x = guide_axis(position = "top"))

Even though the argument title = waiver() it doesn’t seem to work. But works when manually set.

p + guides(x = guide_axis(position = "top", title = "test"))

^{Created on 2021-10-27 by the reprex package (v2.0.1)}

[thomasp85]

@paleolimbot is this something you have time to look at (if not, that is fair)? I guess it is mainly your code

[paleolimbot]

Definitely my code! I'll have a look at this tomorrow.

[paleolimbot]

Ok...I did a bit of sleuthing. I'm going to suggest that this not get fixed until (1) second axes have been deprecated in favour of axis guides (with a transform) and (2) the axis guides are being used on all the Coord subclasses. Or perhaps one of you can see a better solution that's staring me in the nose!

Relevant code:

https://github.com/tidyverse/ggplot2/blob/main/R/coord-cartesian-.r#L154-L173

https://github.com/tidyverse/ggplot2/blob/main/R/layout.R#L234-L258

Implementation that fixes this problem but creates many more:

main...paleolimbot:issue-4650-position-scale-label

Situations to consider:

library(ggplot2)

p <- ggplot(iris, aes(Sepal.Width, Sepal.Length)) +
  geom_point()

# defaults
p

# with setting position in scale
p +
  scale_x_continuous(position = "top") +
  scale_y_continuous(position = "right")

# when title = waiver() and specified in guides()
p + 
  guides(
    x = guide_axis(position = "top", title = waiver()),
    y = guide_axis(position = "right", title = waiver()),
  )

# when title set explicitly
p + 
  guides(
    x = guide_axis(position = "top", title = "explicit x title"),
    y = guide_axis(position = "right", title = "explicit y title"),
  )

# what happens if you set labels(x, y)
p + 
  guides(
    x = guide_axis(position = "top", title = waiver()),
    y = guide_axis(position = "right", title = waiver())
  ) +
  labs(
    x = "x label specified in labels()",
    y = "y label specified in labels()"
  )

# what happens if you set labels(sec.x, sec.y)
p + 
  guides(
    x = guide_axis(position = "top", title = waiver()),
    y = guide_axis(position = "right", title = waiver())
  ) +
  labs(
    sec.x = "sec.x label specified in labels()",
    sec.y = "sec.y label specified in labels()"
  )

# what happens when you specify a second axis
p + 
  scale_x_continuous(sec.axis = sec_axis(trans = ~ . * 10, name = waiver())) +
  scale_y_continuous(sec.axis = sec_axis(trans = ~ . * 10, name = waiver()))

p + 
  scale_x_continuous(sec.axis = sec_axis(trans = ~ . * 10, name = derive())) +
  scale_y_continuous(sec.axis = sec_axis(trans = ~ . * 10, name = derive()))

p + 
  scale_x_continuous(sec.axis = sec_axis(trans = ~ . * 10, name = NULL)) +
  scale_y_continuous(sec.axis = sec_axis(trans = ~ . * 10, name = NULL))

p + 
  scale_x_continuous(sec.axis = sec_axis(trans = ~ . * 10, name = "explicit x title")) +
  scale_y_continuous(sec.axis = sec_axis(trans = ~ . * 10, name = "explicit y title"))

^{Created on 2021-11-11 by the reprex package (v2.0.1)}

# ...and what happens when you do literally all of that using coord_flip()

library(ggplot2)

p <- ggplot(iris, aes(Sepal.Width, Sepal.Length)) +
  geom_point() +
  coord_flip()

# defaults
p

# with setting position in scale
p +
  scale_x_continuous(position = "top") +
  scale_y_continuous(position = "right")

# when title = waiver() and specified in guides()
p + 
  guides(
    x = guide_axis(position = "top", title = waiver()),
    y = guide_axis(position = "right", title = waiver()),
  )

# when title set explicitly
p + 
  guides(
    x = guide_axis(position = "top", title = "explicit x title"),
    y = guide_axis(position = "right", title = "explicit y title"),
  )

# what happens if you set labels(x, y)
p + 
  guides(
    x = guide_axis(position = "top", title = waiver()),
    y = guide_axis(position = "right", title = waiver())
  ) +
  labs(
    x = "x label specified in labels()",
    y = "y label specified in labels()"
  )

# what happens if you set labels(sec.x, sec.y)
p + 
  guides(
    x = guide_axis(position = "top", title = waiver()),
    y = guide_axis(position = "right", title = waiver())
  ) +
  labs(
    sec.x = "sec.x label specified in labels()",
    sec.y = "sec.y label specified in labels()"
  )

# what happens when you specify a second axis
p + 
  scale_x_continuous(sec.axis = sec_axis(trans = ~ . * 10, name = waiver())) +
  scale_y_continuous(sec.axis = sec_axis(trans = ~ . * 10, name = waiver()))

p + 
  scale_x_continuous(sec.axis = sec_axis(trans = ~ . * 10, name = derive())) +
  scale_y_continuous(sec.axis = sec_axis(trans = ~ . * 10, name = derive()))

p + 
  scale_x_continuous(sec.axis = sec_axis(trans = ~ . * 10, name = NULL)) +
  scale_y_continuous(sec.axis = sec_axis(trans = ~ . * 10, name = NULL))

p + 
  scale_x_continuous(sec.axis = sec_axis(trans = ~ . * 10, name = "explicit x title")) +
  scale_y_continuous(sec.axis = sec_axis(trans = ~ . * 10, name = "explicit y title"))

^{Created on 2021-11-11 by the reprex package (v2.0.1)}

[hadley]

Somewhat more minimal reprex:

library(ggplot2)

df <- data.frame(x = 1:2, y = 1:2)

ggplot(df, aes(x, y)) + 
  geom_point() + 
  labs(x = "Long axis label") + 
  guides(x = guide_axis(position = "top"))

^{Created on 2022-04-19 by the reprex package (v2.0.1)}

[yutannihilation]

While #3972 will provide a slightly better result (at least the axis title won't disappear), it seems something is still wrong.

devtools::load_all("~/GitHub/ggplot2")
#> ℹ Loading ggplot2

df <- data.frame(x = 1:2, y = 1:2)

ggplot(df, aes(x, y)) + 
  geom_point() + 
  labs(x = "Long axis label") + 
  guides(x = guide_axis(position = "top"))

^{Created on 2022-07-07 by the reprex package (v2.0.1)}

[yutannihilation]

Adding some tweak to Layout$xlabel() and Layout$ylabel() seems to work at least with CoordCartesian`. Not sure if I can push this into the next release at the moment...

ff2e38f

devtools::load_all("~/GitHub/ggplot2")
#> ℹ Loading ggplot2

df <- data.frame(x = 1:2, y = 1:2)

ggplot(df, aes(x, y)) + 
  geom_point() + 
  labs(x = "Long axis label") + 
  guides(x = guide_axis(position = "top"))

^{Created on 2022-07-08 by the reprex package (v2.0.1)}

devtools::load_all("~/GitHub/ggplot2")
#> ℹ Loading ggplot2

p <- ggplot(iris, aes(Sepal.Width, Sepal.Length)) +
  geom_point()

# defaults
p

# with setting position in scale
p +
  scale_x_continuous(position = "top") +
  scale_y_continuous(position = "right")

# when title = waiver() and specified in guides()
p + 
  guides(
    x = guide_axis(position = "top", title = waiver()),
    y = guide_axis(position = "right", title = waiver()),
  )

# when title set explicitly
p + 
  guides(
    x = guide_axis(position = "top", title = "explicit x title"),
    y = guide_axis(position = "right", title = "explicit y title"),
  )

# what happens if you set labels(x, y)
p + 
  guides(
    x = guide_axis(position = "top", title = waiver()),
    y = guide_axis(position = "right", title = waiver())
  ) +
  labs(
    x = "x label specified in labels()",
    y = "y label specified in labels()"
  )

# what happens if you set labels(sec.x, sec.y)
p + 
  guides(
    x = guide_axis(position = "top", title = waiver()),
    y = guide_axis(position = "right", title = waiver())
  ) +
  labs(
    sec.x = "sec.x label specified in labels()",
    sec.y = "sec.y label specified in labels()"
  )

# what happens when you specify a second axis
p + 
  scale_x_continuous(sec.axis = sec_axis(trans = ~ . * 10, name = waiver())) +
  scale_y_continuous(sec.axis = sec_axis(trans = ~ . * 10, name = waiver()))

p + 
  scale_x_continuous(sec.axis = sec_axis(trans = ~ . * 10, name = derive())) +
  scale_y_continuous(sec.axis = sec_axis(trans = ~ . * 10, name = derive()))

p + 
  scale_x_continuous(sec.axis = sec_axis(trans = ~ . * 10, name = NULL)) +
  scale_y_continuous(sec.axis = sec_axis(trans = ~ . * 10, name = NULL))

p + 
  scale_x_continuous(sec.axis = sec_axis(trans = ~ . * 10, name = "explicit x title")) +
  scale_y_continuous(sec.axis = sec_axis(trans = ~ . * 10, name = "explicit y title"))

^{Created on 2022-07-08 by the reprex package (v2.0.1)}

[teunbrand]

I can probably take this along in #4879. It appears as if we can drop the panel_guide_label and Coord$labels, if we evaluate the guide titles in Layout$xlabel and Layout$ylabel, which puts us in a position to fix this issue.

[teunbrand]

Another thing I encountered is the following:

library(ggplot2)
#> Warning: package 'ggplot2' was built under R version 4.2.1
ggplot(mpg, aes(displ, hwy)) +
  geom_point() +
  guides(x = guide_axis(position = "top", title = "Foo"),
         x.sec = guide_axis(title = "Bar"))
#> Warning: guide_axis(): Discarding guide on merge. Do you have more than one
#> guide with the same position?
#> Warning: guide_axis(): Discarding guide on merge. Do you have more than one
#> guide with the same position?

^{Created on 2022-08-13 by the reprex package (v2.0.1)}

Where I'd think it is not unreasonable to presume that the x.sec guide implicitly has (or should get) position = "bottom".

[teunbrand]

This should work now with the PR, but it is nowhere near finished yet. I've taken an approach similar to yutannihilation's approach (thanks for the inspiration!), but with some extra finagling around for coord_flip().