Is there a way to change the spacing between legend items in ggplot2? I currently have
legend.position ="top"
which automatically produces a horizontal legend. However, the spacing of the items is very close together and I am wondering how to space them farther apart.
I think the best option is to use guide_legend within guides:
p + guides(fill=guide_legend(
keywidth=0.1,
keyheight=0.1,
default.unit="inch")
)
Note the use of default.unit , no need to load grid package.
ggplot2 v3.0.0 released in July 2018 has working options to modify legend.spacing.x, legend.spacing.y and legend.text.
Example: Increase horizontal spacing between legend keys
library(ggplot2)
ggplot(mtcars, aes(factor(cyl), fill = factor(cyl))) +
geom_bar() +
coord_flip() +
scale_fill_viridis_d("Cyl") +
theme(legend.position = 'top',
legend.spacing.x = unit(1.0, 'cm'))
Note: If you only want to expand the spacing to the right of the legend text, use stringr::str_pad()
Example: Move the legend key labels to the bottom and increase vertical spacing
ggplot(mtcars, aes(factor(cyl), fill = factor(cyl))) +
geom_bar() +
coord_flip() +
scale_fill_viridis_d("Cyl") +
theme(legend.position = 'top',
legend.spacing.x = unit(1.0, 'cm'),
legend.text = element_text(margin = margin(t = 10))) +
guides(fill = guide_legend(title = "Cyl",
label.position = "bottom",
title.position = "left", title.vjust = 1))
Example: for scale_fill_xxx & guide_colorbar
ggplot(mtcars, aes(mpg, wt)) +
geom_point(aes(fill = hp), pch = I(21), size = 5)+
scale_fill_viridis_c(guide = FALSE) +
theme(legend.position = 'top',
legend.spacing.x = unit(0.5, 'cm'),
legend.text = element_text(margin = margin(t = 10))) +
guides(fill = guide_colorbar(title = "HP",
label.position = "bottom",
title.position = "left", title.vjust = 1,
# draw border around the legend
frame.colour = "black",
barwidth = 15,
barheight = 1.5))
For vertical legends, settinglegend.key.size only increases the size of the legend keys, not the vertical space between them
ggplot(mtcars) +
aes(fill = factor(cyl), x = cyl) +
geom_bar() +
theme(legend.key.size = unit(1, "cm"))
In order to increase the distance between legend keys, modification of the legend-draw.r function is needed. See this issue for more info
# function to increase vertical spacing between legend keys
# @clauswilke
draw_key_polygon3 <- function(data, params, size) {
lwd <- min(data$size, min(size) / 4)
grid::rectGrob(
width = grid::unit(0.6, "npc"),
height = grid::unit(0.6, "npc"),
gp = grid::gpar(
col = data$colour,
fill = alpha(data$fill, data$alpha),
lty = data$linetype,
lwd = lwd * .pt,
linejoin = "mitre"
))
}
# register new key drawing function,
# the effect is global & persistent throughout the R session
GeomBar$draw_key = draw_key_polygon3
ggplot(mtcars) +
aes(fill = factor(cyl), x = cyl) +
geom_bar() +
theme(legend.key = element_rect(color = NA, fill = NA),
legend.key.size = unit(1.5, "cm"))
A simple fix that I use to add space in horizontal legends, simply add spaces in the labels (see extract below):
scale_fill_manual(values=c("red","blue","white"),
labels=c("Label of category 1 ",
"Label of category 2 ",
"Label of category 3"))
Now that opts is deprecated in ggplot2 package, function theme should be used instead:
library(grid) # for unit()
... + theme(legend.key.height=unit(3,"line"))
... + theme(legend.key.width=unit(3,"line"))
To add spacing between entries in a legend, adjust the margins of the theme element legend.text.
To add 30pt of space to the right of each legend label (may be useful for a horizontal legend):
p + theme(legend.text = element_text(
margin = margin(r = 30, unit = "pt")))
To add 30pt of space to the left of each legend label (may be useful for a vertical legend):
p + theme(legend.text = element_text(
margin = margin(l = 30, unit = "pt")))
for a ggplot2 object p. The keywords are legend.text and margin.
[Note about edit: When this answer was first posted, there was a bug. The bug has now been fixed]
From Koshke's work on ggplot2 and his blog (Koshke's blog)
... + theme(legend.key.height=unit(3,"line")) # Change 3 to X
... + theme(legend.key.width=unit(3,"line")) # Change 3 to X
Type theme_get() in the console to see other editable legend attributes.
Looks like the best approach (in 2018) is to use legend.key.size under the theme object. (e.g., see here).
#Set-up:
library(ggplot2)
library(gridExtra)
gp <- ggplot(data = mtcars, aes(mpg, cyl, colour = factor(cyl))) +
geom_point()
This is real easy if you are using theme_bw():
gpbw <- gp + theme_bw()
#Change spacing size:
g1bw <- gpbw + theme(legend.key.size = unit(0, 'lines'))
g2bw <- gpbw + theme(legend.key.size = unit(1.5, 'lines'))
g3bw <- gpbw + theme(legend.key.size = unit(3, 'lines'))
grid.arrange(g1bw,g2bw,g3bw,nrow=3)
However, this doesn't work quite so well otherwise (e.g., if you need the grey background on your legend symbol):
g1 <- gp + theme(legend.key.size = unit(0, 'lines'))
g2 <- gp + theme(legend.key.size = unit(1.5, 'lines'))
g3 <- gp + theme(legend.key.size = unit(3, 'lines'))
grid.arrange(g1,g2,g3,nrow=3)
#Notice that the legend symbol squares get bigger (that's what legend.key.size does).
#Let's [indirectly] "control" that, too:
gp2 <- g3
g4 <- gp2 + theme(legend.key = element_rect(size = 1))
g5 <- gp2 + theme(legend.key = element_rect(size = 3))
g6 <- gp2 + theme(legend.key = element_rect(size = 10))
grid.arrange(g4,g5,g6,nrow=3) #see picture below, left
Notice that white squares begin blocking legend title (and eventually the graph itself if we kept increasing the value).
#This shows you why:
gt <- gp2 + theme(legend.key = element_rect(size = 10,color = 'yellow' ))
I haven't quite found a work-around for fixing the above problem... Let me know in the comments if you have an idea, and I'll update accordingly!
- I wonder if there is some way to re-layer things using
$layers...
Use any of these
legend.spacing = unit(1,"cm")
legend.spacing.x = unit(1,"cm")
legend.spacing.y = unit(1,"cm")
来源：https://stackoverflow.com/questions/11366964/is-there-a-way-to-change-the-spacing-between-legend-items-in-ggplot2