library("grid")
library("ggplot2")
library("ggfun")

element_roundrect

The element_roundrect works like element_rect to draw round rectangle background. We can use it to adjust theme elements, including legend, strip, panel and plot background.

p <- ggplot(mpg, aes(displ, cty)) + geom_point()
p <- p + facet_grid(cols = vars(cyl))
p <- p + theme(strip.background=element_roundrect(fill="grey40", color=NA, r=0.15))
p

p2 <- ggplot(mtcars, aes(mpg, disp, color=factor(cyl), size=cyl)) +
         geom_point()
p2 + theme(legend.background=element_roundrect(color="#808080", linetype=2))

gglegend

p <- ggplot(mtcars, aes(mpg, disp)) + geom_point()
data <- data.frame(colour = c("red",  "blue"), VALUE = c("A", "B"))
gglegend(aes(colour = VALUE, label=VALUE), data, geom_text, p)

set_font

d <- data.frame(x=rnorm(10), y=rnorm(10), lab=LETTERS[1:10])
p <- ggplot(d, aes(x, y)) + geom_text(aes(label=lab), size=5)
set_font(p, family="Times", fontface="italic", color='firebrick')
## Warning in grid.Call.graphics(C_text, as.graphicsAnnot(x$label), x$x, x$y, :
## Windows字体数据库里没有这样的字体系列
## Warning in grid.Call.graphics(C_text, as.graphicsAnnot(x$label), x$x, x$y, :
## Windows字体数据库里没有这样的字体系列
## Warning in grid.Call.graphics(C_text, as.graphicsAnnot(x$label), x$x, x$y, :
## Windows字体数据库里没有这样的字体系列
## Warning in grid.Call.graphics(C_text, as.graphicsAnnot(x$label), x$x, x$y, :
## Windows字体数据库里没有这样的字体系列

facet_set

Manually specifying facet labels.

library(ggplot2)
library(ggfun)
p <- ggplot(mtcars, aes(disp, drat)) + 
  geom_point() + 
  facet_grid(cols=vars(am), rows=vars(cyl))
p + facet_set(label=c(`0`="Zero", `6`="Six"))

Supports labeller:

p + facet_set(label=label_both)

Add a facet label to a plot.

p + facet_set(label="TEST")

With the ggplotify package, we can use facet_set to add a facet label to almost any plot in R.

## please try:

ggplotify::as.ggplot(~barplot(1:10, col=rainbow(10))) +
  facet_set('a barplot in base')