I am making a plot where variable descriptions appear in the left “strip” text of facet_wrap() facets. Sometimes when variable descriptions are long enough to be wrapped, the last line comes out very short. This can make the plot look weird, especially if the text is right-justified.
Here’s a reproducible example:
library('ggplot2')
dat <- data.frame(variable=rep(c('Frogs','Kittens wearing tiny hats','Mars',
'Really long name that will wrap to three lines','Tacos',
'Your local public library'),each=2))
dat$stratify <- rep(c('Yes','No'),6)
dat$beta <- 1:12
dat$lower_ci <- dat$beta - (1:12)/10
dat$upper_ci <- dat$beta + (1:12)/10
dat$is_oddvar <- grepl('Frogs|Mars|Tacos',dat$variable) # Every other variable in the plot has a grey stripe
ggplot(dat,aes(x=beta,xmin=lower_ci,xmax=upper_ci,y=stratify,color=stratify)) +
# Gray/white stripes
geom_rect(aes(fill=is_oddvar),color='grey90',xmin = -Inf,xmax = Inf,ymin = -Inf,ymax = Inf) +
scale_fill_manual(breaks=c(T,F),values=c('grey90','white'),guide=NULL) +
facet_wrap('variable',strip.position='left',ncol=1,scales='fixed',labeller=label_wrap_gen(width=24)) +
# Points and confidence intervals
geom_point() + geom_linerange(linewidth=1) +
# Themes/general plot appearance
theme_bw() +
theme(panel.spacing=unit(0,'lines'),panel.border=element_blank(),
axis.ticks.y=element_blank(),axis.text.y=element_blank(),
axis.title.y=element_blank(),axis.title.x=element_blank(),
strip.text.y.left=element_text(angle=0,hjust=1),strip.background=element_blank(),
legend.position='bottom',legend.title=element_blank())
Is there a way to make the labeller split lines more evenly when they’re long enough that they need to be wrapped? For example, to wrap “Kittens wearing tiny hats” as “Kittens wearing | tiny hats” instead of “Kittens wearing tiny | hats”?
1
I found out that nchar() can be used to control the length of the strings of the labeller. Since nchar() returns the number of characters of the input strings, we can use facet_wrap() variable as its input strings, and then divide its return with a fraction to get a numeric vector of lengths. Then, we use this vector as the value of width in label_wrap_gen().
In your example, by trial and error I found 0.51 is a good choice. I then changed your facet_wrap(...) line to the following:
facet_wrap(vars(variable),strip.position='left',ncol=1,scales='fixed',
labeller=label_wrap_gen(width = nchar(vars(variable))/0.51))
Here is the result:
3
One approach with {ggtext}:
library(ggplot2)
library(ggtext)
data.frame(variable = c('Frogs','Kittens wearing tiny hats','Mars',
'Really long name that will wrap to three lines','Tacos',
'Your local public library')
) |>
ggplot() +
geom_point(aes(1, 1)) +
facet_wrap(~ variable, strip.position = 'left', ncol = 1) +
theme(strip.text = element_textbox_simple(maxwidth = unit(1, 'in'),
halign = 1,
margin = margin(0, 5, 0, 0)
),
strip.background=element_blank(),
axis.ticks = element_blank(),
axis.text = element_blank()
) +
labs(x = '', y = '')
Note that {ggtext} also allows to render markdown, incl. HTML. So one should be able to use the whole works of CSS text wrapping and aligning (haven’t tried though).