ggplot geom_text font size control

Question

I tried to change the font to 10 for the labels of my bar plot in ggplot2 by doing something like this:

ggplot(data=file,aes(x=V1,y=V3,fill=V2)) +
    geom_bar(stat="identity",position="dodge",colour="white") + 
    geom_text(aes(label=V2),position=position_dodge(width=0.9),
                                                 hjust=1.5,colour="white") +
    theme_bw()+theme(element_text(size=10))

ggsave(filename="barplot.pdf",width=4,height=4)

but the resulting image has super big font size for the bar plot labels.

Then I thought of modifying in geom_text() with this:

geom_text(size=10,aes(label=V2),position=position_dodge(width=0.9),
                                                   hjust=1.5,colour="white")

The label font is even bigger...

I can change the size within geom_text to something like 3 and now it looks like font 10, similar to the axis labels.

I'm wondering what's going on? Does theme(text=element_text(size=10)) doesn't apply to labels?

And why size of 10 in geom_text() is different from that in theme(text=element_text()) ?

user20650 · Accepted Answer · 2014-07-31 16:42:27Z

233

Here are a few options for changing text / label sizes

library(ggplot2)

# Example data using mtcars

a <- aggregate(mpg ~ vs + am , mtcars, function(i) round(mean(i)))

p <- ggplot(mtcars, aes(factor(vs), y=mpg, fill=factor(am))) + 
            geom_bar(stat="identity",position="dodge") + 
            geom_text(data = a, aes(label = mpg), 
                            position = position_dodge(width=0.9),  size=20)

The size in the geom_text changes the size of the geom_text labels.

p <- p + theme(axis.text = element_text(size = 15)) # changes axis labels

p <- p + theme(axis.title = element_text(size = 25)) # change axis titles

p <- p + theme(text = element_text(size = 10)) # this will change all text size 
                                                             # (except geom_text)

For this And why size of 10 in geom_text() is different from that in theme(text=element_text()) ?

Yes, they are different. I did a quick manual check and they appear to be in the ratio of ~ (14/5) for geom_text sizes to theme sizes.

So a horrible fix for uniform sizes is to scale by this ratio

geom.text.size = 7
theme.size = (14/5) * geom.text.size

ggplot(mtcars, aes(factor(vs), y=mpg, fill=factor(am))) + 
  geom_bar(stat="identity",position="dodge") + 
  geom_text(data = a, aes(label = mpg), 
            position = position_dodge(width=0.9),  size=geom.text.size) + 
  theme(axis.text = element_text(size = theme.size, colour="black"))

This of course doesn't explain why? and is a pita (and i assume there is a more sensible way to do this)

edited Jul 31, 2014 at 16:42

answered Jul 31, 2014 at 15:07

user20650

26.1k5 gold badges59 silver badges95 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

olala Over a year ago

interesting, what did you check to find out the 14/5 ratio ?

olala Over a year ago

i see. you remind me of something I read recently, I guess it's the difference in units, geom_text default of 5 might be 5mm and the theme() size unit is point. 1 point is 1/72 inch=0.35mm, so 1 in geom_text() is 1mm, 1/0.35 =~ 14/5 :)

user20650 Over a year ago

agstudy's answer describes the why stackoverflow.com/questions/17311917/ggplot2-the-unit-of-size

Nova Over a year ago

And for those of us who want to go the other way, and convert geom_text to "regular" font size, you can just multiply by 0.36.

SarahS · Accepted Answer · 2023-06-22 23:41:40Z

25

I had this question, and found on the aesthetic specifications ggplot help page that they add in a handy function for converting mm (default for geom_text for consistency with lines and point) to points (the scale for theme)- you simply put in your font size (in pt), then type /.pt.

So your code would be:

ggplot(data=file,aes(x=V1,y=V3,fill=V2)) +
geom_bar(stat="identity",position="dodge",colour="white") + 
geom_text(aes(label=V2),position=position_dodge(width=0.9),
          hjust=1.5,colour="white", size = 10/.pt) +
theme_bw()

This conversion does the equivalent of what Nova mentioned above. Hope this is helpful for anyone looking for this answer in the future.

answered Jun 22, 2023 at 23:41

SarahS

4204 silver badges12 bronze badges

1 Comment

Turan Over a year ago

This should be the accepted answer as of 2023. Use the built-in helper function .pt to divide your pt-input by.

jakubuilds · Accepted Answer · 2022-12-19 16:19:12Z

3

Take a look at the relevant entry in ggplot2's customization FAQ: https://ggplot2.tidyverse.org/articles/faq-customising.html#what-is-the-default-size-of-geom_text-and-how-can-i-change-the-font-size-of-geom_text

You can modify the default size of geom_text() by placing update_geom_defaults("text", list(size = X), where X is your choice of new size, at the beginning of your script.

answered Dec 19, 2022 at 16:19

jakubuilds

314 bronze badges

Comments

Eric Aya · Accepted Answer · 2023-11-22 09:50:13Z

0

Adding to the accepted answer:

Look up ?.pt and you will understand what 14/5 means and why it is needed.

edited Nov 22, 2023 at 9:50

Eric Aya

70.2k36 gold badges190 silver badges266 bronze badges

answered Nov 22, 2023 at 8:08

Grand

12 bronze badges

1 Comment

Michele La Ferla Over a year ago

This does not provide an answer to the question. Once you have sufficient reputation you will be able to comment on any post; instead, provide answers that don't require clarification from the asker. - From Review

Collectives™ on Stack Overflow

ggplot geom_text font size control

4 Answers 4

4 Comments

1 Comment

Comments

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

4 Comments

1 Comment

Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related