An R package that draws curly braces in ggplot2.
Version 0.1.1 (Feb 2024) of ggbrace removed the original
geom_brace function, which plots braces within the confines
of the x-y-values. The same functionality can now be achieved with
stat_brace( outside = FALSE ). Additionally, the text
functionality is now its own function stat_bracetext which
allows for more customization of the text using the same arguments that
would be used in geom_text or geom_label. By
default stat_brace uses geom="text" which can
be changed e.g. by stat_brace(geom="label").
Install the package from CRAN
install.packages("ggbrace")or from this git repository:
devtools::install_github("nicolash2/ggbrace")The new version of ggbrace uses only stat_brace to
automatically enclose data points. stat_bracetext is used
to generate fitting text.
In our example we use the iris data to create a dotplot. Then we look at how each of the three different modes draws braces to that plot.
library(ggplot2)
library(ggbrace)
data(iris)
plt <- ggplot(iris, aes(x=Sepal.Length, y=Sepal.Width, color=Species, label=Species)) +
geom_point() +
theme_classic() +
theme(legend.position="none")
plt + stat_brace()
We can add labels to the braces. For that the
stat_bracetext is used.
plt +
stat_brace() +
stat_bracetext()
We can modify the text in the same way we would modify other text in
ggplot. We can also switch between different text geoms
(e.g. geom=label).
plt +
stat_brace() +
stat_bracetext(size=6, angle=15, fontface="bold")
We can rotate the braces by 90, 180 or 270 degrees via the
rotate argument. Note that any changes in
stat_brace also have to be made in
stat_bracetext so that the text appears at the right
position
plt +
stat_brace(rotate = 90) +
stat_bracetext(rotate = 90)
By default, the location of the brace is beside the data points by
default. We can change that by setting the paramter outside
to FALSE.
plt + stat_brace(outside = FALSE)
By default, braces have a position and shape that is calculated based
on their data points.The position can be changed with the parameters
distance (to the data points) and outerstart
(in the coordinate system). The width of the braces can be set with the
width argument (absolute coordinate system units), while
the bending of the brace can be set with bending (number
from 0 to 1).
plt + stat_brace(distance = 2) # the braces are put at a defined distance to the last data point of their group
plt + stat_brace(outerstart = 5) # all braces are put at the same position
plt + stat_brace(outerstart = 5, width = 1) # all braces get the same width
plt + stat_brace(outerstart = 5, width = 1, bending = 0.1) # all braces get the same curvature
To vizualize the brace outside of the plotting area, we can simply
use two ggplot2 functions. - coord_cartesian needs to be
mentioned with x and/or y range of the plotting area and the parameter
clip="off" to allow plotting of objects outside of that
area. - within the theme function, plot.margin
needs to be set to expand the outside area. This happens with 4 numbers
(above, right, below, left). This can best be achieved with the
"npc" unit, as it reflects the plot units and is therefore
maintained independent of the pixels, cm, etc. Other units can be seen
with ?unit (under grid).
plt + stat_brace(outerstart = 4.5) +
coord_cartesian(y=range(iris$Sepal.Width), clip = "off") + #for the range just use the data for the respective axis
theme(plot.margin = unit(c(0.25, 0.11, 0.11, 0.11), units="npc"))
Use discreteAxis=TRUE to ensure the braces embrace the
category.
df <- iris
df$Group <- substring(iris$Species,1,1)
ggplot(df, aes(x=Species, y=Sepal.Length, group=Group)) +
geom_jitter() +
stat_brace(discreteAxis=TRUE)
Use bracketType="square" to produce square brackets
instead of curly ones. The bracket have the same width as the curly ones
in order to comply with the text. Use the width parameter
to adjust their size.
plt + stat_brace(bracketType="square", width=.2)