Plotting labels on barplots using type_text() fails

[Koalha]

Thanks for this awesome package! It's reignited my love for base-type graphics.

While testing the package, I found a bug / inconsistency / came up with a feature request. I was trying to create horizontal barcharts with labels. Plotting the label positions using tinyplot_add(type = type_points()) works as expected, but plotting the actual labels results in an error. The expected behaviour is for the type_text() to work in the same way as type_points(). Incidentally, it seems that plotting the text alone fails as well.

library(dplyr)
#> 
#> Attaching package: 'dplyr'
#> The following objects are masked from 'package:stats':
#> 
#>     filter, lag
#> The following objects are masked from 'package:base':
#> 
#>     intersect, setdiff, setequal, union
library(tinyplot)
data(penguins)

percent_labeller <- function(estimate, cutoff = 2) {
  out <- round(estimate * 100)
  too_small <- out < cutoff
  out <- out |> as.character()
  out[too_small] <- ""
  out
}

penguins <- penguins |> as_tibble()

## Remove missing data for this test
penguins <- penguins |> na.omit()

## Calculate species by islands
e1 <- penguins |>
  count(island, species, .drop = FALSE) |>
  mutate(p = n / sum(n), .by = island)

## Remove labels for very small or nonexistent groups
e1 <- e1 |> mutate(lab = percent_labeller(p))

## Calculate label positions
e1 <- e1 |>
  arrange(island, species) |>
  mutate(lab_pos = cumsum(p) - 0.5 * p, .by = island)


## Plotting the data works
tinyplot(
  p ~ island | species,
  type = type_barplot(),
  data = e1,
  flip = TRUE
)

## Adding the label positions as points works
tinyplot_add(
  lab_pos ~ island,
  type = type_points(),
  col = "white"
)

## Adding the labels themselves fails
tinyplot_add(
  lab_pos ~ island,
  type = type_text(labels = e1$lab),
  col = "white"
)
#> Error in Summary.factor(structure(c(1L, 1L, 1L, 2L, 2L, 2L, 3L, 3L, 3L: 'range' not meaningful for factors

## Plotting the labels alone fails as well
tinyplot_add(
  lab_pos ~ island,
  type = type_text(labels = e1$lab),
  col = "white",
  data = e1
)
#> Error in Summary.factor(structure(c(1L, 1L, 1L, 2L, 2L, 2L, 3L, 3L, 3L: 'range' not meaningful for factors

^{Created on 2025-09-10 with reprex v2.1.1}

[zeileis]

Thanks for the report, much appreciated. This should definitely be improved. I think all it needs is to convert the factor variable to numeric, i.e., you can work around by using lab_pos ~ as.numeric(island) in your code.

I've proposed to do this internally automatically in type_text() via PR #470 with the following example as a test:

tab = mtcars |>
  xtabs(formula = ~ cyl) |>
  as.data.frame()
tinyplot(Freq ~ cyl, data = tab, type = "barplot")
tinyplot_add(type = "text", labels = tab$Freq, pos = 3, xpd = TRUE)

[grantmcdermott]

Thanks for the report @Koalha.

@zeileis Beyond your proposed fix, I wonder if we shouldn't support a type_barplot(label = TRUE) argument that would add these labels directly?

[zeileis]

Yes, maybe. Although one argument wouldn't be enough, would it? We would need to decide whether we want to display

• absolute and/or (conditional) relative frequencies
• ...or use some other formatter, e.g., for adding custom prefixes, suffixes, rounding, etc. (especially for other aggregation FUNctions)
• at the top or bottom or center of the box
• whether to adjust or modify the position
• what cex or col to use for the text (or possibly other font properties)
• ...

In short, this is not so trivial, unfortunately.