Add several lines of variable text in fixed positions to a ggplot facet - r

Question

I am tryig to add several lines of text to this facet. Sorry about the mess of code
From the object means1 I want to add the values of the variables "pCensCom" "pCensEx" and "pCensReg" for each facet, as described in the following figure
This is the object 'censTot1' used to build the chart
censo censTot tipoAni censAn año pCensAn
1: 2010-01-01 42 Hembra adulta 27 2010 64.285714
2: 2010-01-01 42 Joven 4 2010 9.523810
3: 2010-01-01 42 Macho adulto 1 2010 2.380952
4: 2010-01-01 42 Ternero 10 2010 23.809524
5: 2010-01-02 42 Hembra adulta 27 2010 64.285714
---
7300: 2014-12-30 57 Ternero 16 2014 28.070175
7301: 2014-12-31 57 Hembra adulta 32 2014 56.140351
7302: 2014-12-31 57 Joven 7 2014 12.280702
7303: 2014-12-31 57 Macho adulto 2 2014 3.508772
7304: 2014-12-31 57 Ternero 16 2014 28.070175
The following describes the code used to design the figure
# Plot color background
# %%%%%%%%%%%%%%%%%%%%%%
bg0<-data.table()
for(i in 1:5){
bg<-data.table(xstart=c(as.Date(paste0(años[i],"-01-01"), format="%Y-%m-%d"),as.Date(paste0(años[i],"-03-21"), format="%Y-%m-%d"), as.Date(paste0(años[i],"-06-21"),format = "%Y-%m-%d"),as.Date(paste0(años[i],"-09-21"),format = "%Y-%m-%d"),
as.Date(paste0(años[i],"-12-21"),format = "%Y-%m-%d")),xend=c(as.Date(paste0(años[i],"-03-21"), format="%Y-%m-%d"),
as.Date(paste0(años[i],"-06-21"),format = "%Y-%m-%d"), as.Date(paste0(años[i],"-09-21"),format = "%Y-%m-%d"),
as.Date(paste0(años[i],"-12-21"),format = "%Y-%m-%d"),as.Date(paste0(años[i],"-12-31"),format = "%Y-%m-%d")),
Estacion=c("Invierno","Primavera","Verano","Otoño","Invierno"))
l=list(bg0,bg); bg0<-rbindlist(l, fill=TRUE)
}
bg0<-bg0[,Estacion:=factor(ordered(Estacion,levels=c("Invierno","Primavera", "Verano", "Otoño")))]
cbPalette<-c("#FF3300","#006633","#FFFF00","#0000FF")
plotbg<-ggplot()+ geom_rect(data = bg0, aes(xmin = xstart, xmax = xend, ymin = 0, ymax = Inf, fill = Estacion), alpha = 0.10)+ scale_fill_manual(values=cbPalette)+ guides(fill=FALSE)+theme_bw()
means1<-data.table(tipoAni=c("Hembra adulta","Joven","Macho adulto","Ternero"),pCensCom=c(62.3,17.8,0.9,19.37),pCensEx=c(61.4,16.1,1.9,20.6),pCensReg=c(63.0,17.9,1.6,24.7))
# Plot
# %%%%
plotbg + geom_line(data=censTot1,aes(x=censo,y=pCensAn))+ facet_grid(tipoAni ~ .)+ xlab("Censos diarios") + ylab("Animales (%)") +theme_bw()+ theme(strip.text.x = element_text(size=8),strip.text.y = element_text(size=10, face="bold"),strip.background = element_rect(colour="red", fill="#CCCCFF"))
Please I need help, I tried several times using the functions annotation_custom, grobTree and textGrob and I have not been able to achieve

Answer 1

Here is a simplified answer. First I simulate some data dat, then a second data.table backgr that has the information for the background, and lastly textdt, which holds the information about the text elements.
The code looks like this:
library(data.table)
library(ggplot2)
library(scales)
dat <- data.table(x = rep(1:100, 2),
group = rep(LETTERS[1:2], each = 100),
val = rnorm(200))
dat[, price := 100 + cumsum(val), by = group]
# plot empty
ggplot(dat, aes(x = x, y = price)) +
geom_line() +
facet_grid(group~.)
# plot with added polygons
# for the background colors
backgr <- data.table(minval = c(10, 40, 60, 90),
maxval = c(20, 60, 80, 100),
backgroup = LETTERS[1:4])
# for the text elements
textdt <- data.table(xval = c(10, 50, 70),
yval = c(105, 100, 95),
textlabel = c("foo", "bar", "lorum"),
group = c("A", "A", "B"))
# plot
ggplot() +
geom_rect(data = backgr, aes(xmin = minval, xmax = maxval, ymin = -Inf,
ymax = Inf, fill = backgroup)) +
geom_line(data = dat, aes(x = x, y = price)) +
geom_text(data = textdt, aes(x = xval, y = yval, label = textlabel,
group = group)) +
facet_grid(group~.) +
scale_fill_manual(values = alpha(c("red", "green", "blue", "yellow"), 0.5))
Which results in a plot like this, which you can adjust to fit your data: