Axis label formatting fails when position is changed

[joelnitta]

Thanks for the great package!

I would like to format labels and move the label position using the position argument of scale_x etc, but it doesn't seem to work.

library(ggplot2)
library(ggtext)

labels <- c(
  setosa = "This is<br>*I. setosa*",
  virginica = "This is<br>*I. virginica*",
  versicolor = "This is<br>*I. versicolor*"
)

# Works with labels on bottom
ggplot(iris, aes(Species, Sepal.Width)) +
  geom_boxplot() +
  scale_x_discrete(
    name = NULL,
    labels = labels
  ) +
  theme(
    axis.text.x = element_markdown(color = "black", size = 11)
  )

# But not on top
ggplot(iris, aes(Species, Sepal.Width)) +
  geom_boxplot() +
  scale_x_discrete(
    position = "top",
    name = NULL,
    labels = labels
  ) +
  theme(
    axis.text.x = element_markdown(color = "black", size = 11)
  )

^{Created on 2019-09-29 by the reprex package (v0.3.0)}

Session info

sessionInfo()
#> R version 3.6.0 (2019-04-26)
#> Platform: x86_64-apple-darwin15.6.0 (64-bit)
#> Running under: macOS High Sierra 10.13.6
#> 
#> Matrix products: default
#> BLAS:   /Library/Frameworks/R.framework/Versions/3.6/Resources/lib/libRblas.0.dylib
#> LAPACK: /Library/Frameworks/R.framework/Versions/3.6/Resources/lib/libRlapack.dylib
#> 
#> locale:
#> [1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8
#> 
#> attached base packages:
#> [1] stats     graphics  grDevices utils     datasets  methods   base     
#> 
#> other attached packages:
#> [1] ggtext_0.1.0  ggplot2_3.2.1
#> 
#> loaded via a namespace (and not attached):
#>  [1] Rcpp_1.0.2       pillar_1.4.2     compiler_3.6.0   highr_0.8       
#>  [5] tools_3.6.0      digest_0.6.21    evaluate_0.14    tibble_2.1.3    
#>  [9] gtable_0.3.0     pkgconfig_2.0.3  rlang_0.4.0      curl_4.2        
#> [13] yaml_2.2.0       xfun_0.9         withr_2.1.2      dplyr_0.8.3     
#> [17] stringr_1.4.0    httr_1.4.1       knitr_1.25       xml2_1.2.2      
#> [21] grid_3.6.0       tidyselect_0.2.5 gridtext_0.1.0   glue_1.3.1      
#> [25] R6_2.4.0         rmarkdown_1.15   purrr_0.3.2      magrittr_1.5    
#> [29] scales_1.0.0     htmltools_0.3.6  assertthat_0.2.1 mime_0.7        
#> [33] colorspace_1.4-1 labeling_0.3     stringi_1.4.3    lazyeval_0.2.2  
#> [37] munsell_0.5.0    markdown_1.1     crayon_1.3.4

[clauswilke]

This actually works. You have to style the correct theme element.

library(ggplot2)
library(ggtext)

labels <- c(
  setosa = "This is<br>*I. setosa*",
  virginica = "This is<br>*I. virginica*",
  versicolor = "This is<br>*I. versicolor*"
)

ggplot(iris, aes(Species, Sepal.Width)) +
  geom_boxplot() +
  scale_x_discrete(
    position = "top",
    name = NULL,
    labels = labels
  ) +
  theme(
    axis.text.x.top = element_markdown(color = "black", size = 11)
  )

^{Created on 2019-10-07 by the reprex package (v0.3.0)}

[joelnitta]

I see, thanks for pointing that out! Looking at the ggplot2 reference, "axis.title.*.* inherits from axis.title.*", so does that mean in this case ggtext is not behaving as expected?

[clauswilke]

No, it behaves as expected. axis.text.x.top is still an element_text(), so it'll behave like one. Inheritance only means that the parameter values are reused. See the following example.

library(ggplot2)
library(ggtext)

labels <- c(
  setosa = "This is<br>*I. setosa*",
  virginica = "This is<br>*I. virginica*",
  versicolor = "This is<br>*I. versicolor*"
)

# example 1, parameters are inherited but no markdown
ggplot(iris, aes(Species, Sepal.Width)) +
  geom_boxplot() +
  scale_x_discrete(
    position = "top",
    name = NULL,
    labels = labels
  ) +
  theme(
    axis.text.x = element_markdown(color = "red", size = 15)
  )

# example 2, now with markdown
ggplot(iris, aes(Species, Sepal.Width)) +
  geom_boxplot() +
  scale_x_discrete(
    position = "top",
    name = NULL,
    labels = labels
  ) +
  theme(
    axis.text.x = element_text(color = "red", size = 15),
    axis.text.x.top = element_markdown()
  )

^{Created on 2019-10-07 by the reprex package (v0.3.0)}

[joelnitta]

I see, thanks for taking the time to explain.