How to add a black overlay semi transparent layer above the background image in r?

Question

I am using background image in the plot but the colors of the plot is mixing up with the image so I would like to add an overlay semitransparent black layer to the background image so that plot colors can stand out and do not mix with the background..

I have tried adding geom_rect() but that doesn't work well geom_rect(aes(xmin = min(date), xmax=max(date), ymin = -Inf, ymax=Inf), fill = "black", alpha = 0.3)

How can I just add a semitransparent overlay layer over the complete background image.

failed result

df

library(tidyverse)
library(lubridate)
library(ggpubr)
library(grid)
library(jpeg)

file_url1 <- "https://raw.githubusercontent.com/johnsnow09/covid19-df_stack-code/main/ts_all_long4.csv"

ts_all_long <- read.csv(url(file_url1))

ts_all_long <- ts_all_long %>%
  mutate(date = as.Date(date))

image used: https://github.com/johnsnow09/covid19-df_stack-code/blob/a00c8820363f2163837d24f801f7c5b85167e0aa/coronavirus-4972480_1920.jpg

without geom_rect():

ts_all_long %>% 
  filter(Country.Region == "Brazil") %>% 
  
  ggplot(aes(x = date, y = Confirmed_daily)) +
  background_image(readJPEG("Covid 19 images/coronavirus-4972480_1920.jpg")) +
  geom_area(size = 1, col = "#f08080", fill = "#f08080", alpha = 0.5)

with geom_rect():

ts_all_long %>% 
  filter(Country.Region == "Brazil") %>% 
  
  ggplot(aes(x = date, y = Confirmed_daily)) +
  background_image(readJPEG("Covid 19 images/coronavirus-4972480_1920.jpg")) +
  geom_rect(aes(xmin = min(date), xmax=max(date), ymin = -Inf, ymax=Inf),
            fill = "black", alpha = 0.3) +
  geom_area(size = 1, col = "#f08080", fill = "#f08080", alpha = 0.5)

Answer 1

Based on this answer I tried annotate() instead of geom_rect(), which does the trick:

ts_all_long %>% 
  filter(Country.Region == "Brazil") %>% 
  
  ggplot(aes(x = date, y = Confirmed_daily)) +
  background_image(readJPEG("/home/johannes/Downloads/coronavirus-4972480_1920.jpg")) +
  annotate("rect", xmin = min(ts_all_long$date), xmax = max(ts_all_long$date), ymin = -Inf, ymax = Inf,
            fill = "black", alpha = 0.3) +
  geom_area(size = 1, col = "#f08080", fill = "#f08080", alpha = 0.5)

^{Created on 2021-04-20 by the reprex package (v2.0.0)}

However, I think it would actually look better to do something like this:

ts_all_long %>% 
  filter(Country.Region == "Brazil") %>% 
  
  ggplot(aes(x = date, y = Confirmed_daily)) +
  background_image(readJPEG("/home/johannes/Downloads/coronavirus-4972480_1920.jpg")) +
  geom_area(size = 1, col = "white", fill = "#f08080", alpha = 0.5)

^{Created on 2021-04-20 by the reprex package (v2.0.0)}