ggplot - ensure same position of text when resizing the plot

Question

Have a look at the following plot:

ggplot(mtcars, aes(x = mpg, y = wt)) + 
  geom_point() + 
  geom_hline(yintercept = 3) + 
  theme(axis.title.x = element_text(vjust = 85))

As you can notice, the x-axis title has been shifted and is located just below the horizontal line.

My current plot window dimensions are 17.38312 x 16.98625 cm. If I change them to smaller ones (e.g. 12.88521 x 11.08604 cm), then the plot looks like this:

So as you can see, the title is no longer in the same position, now it's above the horizontal line. If we make the plot larger (24.15646 x 20.32000 cm), then the title is much below the horizontal line.

I tried using coord_fixed(), but that didn't seem to be intended for these types of problems.

How can I ensure that when I am using hjust and vjust I am not moving the text in some absolute units, but rather in relative terms of the graph width/height, so that the text always remains in the same position when I resize the graph?

I doubt this is possible with `vjust`, which is intended to justify text relative to the outside boundaries of that text (e.g. `hjust` is 0 for left-aligned, 1 for right-aligned). The text size (relative to the plot) obviously changes as you resize your window, so this is never going to work. You would be better off placing the label with `geom_text` or `annotate`. — Andrew Gustar, Apr 30 '23 at 14:46
Are you trying to add the text immediately below the hline, or is it at a proportion of the screen plot region dimensions? — r2evans, Apr 30 '23 at 14:53
`vjust` is always relative to the string's _height_; `hjust` is always relative to the string's _width_; neither of those is relative to the plotting region, and cannot be warped into being so. If you want the text always plotted at a relative position in the plotting region, `hjust` and `vjust` are not your tools. — r2evans, Apr 30 '23 at 15:37
You can get what I think you want by removing your `theme(.)` and adding `+ geom_text(data = ~ with(., data.frame(mpg = mean(range(mpg)), wt = 3)), label = "mpg", vjust = 1.1) + scale_x_continuous(name = NULL)`. — r2evans, Apr 30 '23 at 16:52
OP, what is your desired output here? If you want to put text into the plot area, moving the axis title text is just about the worst way I can think of doing it (and is almost guaranteed to be inconsistent) — chemdork123, Apr 30 '23 at 19:33
@chemdork123 The purpose is to pretend that the hline is actually the x-axis line and then have the title of the axis below it — J. Doe, Apr 30 '23 at 19:36
I would suggest [this answer](https://stackoverflow.com/a/73566140/9664796) could be useful. If `geom_hline()` here represents your x axis, there's some nice formatting from the `ggh4x` package. — chemdork123, Apr 30 '23 at 21:32

score 1 · Accepted Answer · answered Apr 30 '23 at 22:09

Another option is to use the geomtextpath package, which offers the possibility to add a label to a line, in this case a hline. you can then modify the relative label position with a vjust to your liking.

> library(geomtextpath)
Loading required package: ggplot2
> 
> ggplot(mtcars, aes(x = mpg, y = wt)) + 
+   geom_point() + 
+   geom_texthline(yintercept = 3, vjust = 1.5, label = "mpg")

Figure dimensions 2x3 inches

Figure dimensions 3x3 inches

^{Created on 2023-04-30 with reprex v2.0.2}

score 0 · Answer 2 · answered Apr 30 '23 at 20:15

I think the problem will be solved if you fix the plot size and save different plots with the same dimension. Also, the geom_text is a better choice for resizing. Other options such as geom_text_repel and geom_label_repel from ggrepel package and geom_label_interactive from ggiraph are also available. Kindly ignore the irrelevant example below and re-write the codes if it is useful.

library(ggplot2)
library(ggiraph)
library(ggrepel)
df <- data.frame(x=1:5, y=1:5, text=LETTERS[1:5])

ggplot(df, aes(x, y)) +
  geom_text(aes(label = text))+
  labs(title='using geom_text')
ggsave('file1.jpg', height = 24, width = 20, units = 'cm')

ggplot(df, aes(x, y)) +
  geom_text_repel(aes(label = text))+
  labs(title='using geom_text_repel')
ggsave('file2.jpg', height = 24, width = 20, units = 'cm')

ggplot(df, aes(x, y)) +
  geom_label_repel(aes(label = text))+
  labs(title='using geom_label_repel')
ggsave('file3.jpg', height = 24, width = 20, units = 'cm')

ggplot(df, aes(x, y, label = text)) +
  geom_label_interactive(aes(tooltip = text))+
  labs(title='using geom_label_interactive')
ggsave('file4.jpg', height = 24, width = 20, units = 'cm')

I hope it helps.

ggplot - ensure same position of text when resizing the plot

2 Answers2