如何在R中的背景图像上方添加黑色覆盖半透明层? [英] How to add a black overlay semi transparent layer above the background image in r?

问题描述

我在绘图中使用了背景图像，但是绘图中的颜色与图像混合在一起，所以我想在背景图像中添加一个覆盖半透明黑色层strong>，以使绘图颜色能够突出显示并且不会与背景混合.

我尝试添加 geom_rect()，但效果不佳 geom_rect(aes(xmin = min(date)，xmax = max(date)，ymin = -Inf，ymax = Inf)，填充=黑色"，alpha = 0.3)

如何在整个背景图像上添加一个半透明的覆盖层.

失败的结果

df

 库(tidyverse)库(润滑)图书馆(ggpubr)图书馆(网格)图书馆(jpeg)file_url1<-" https://raw.githubusercontent.com/johnsnow09/covid19-df_stack-code/main/ts_all_long4.csvts_all_long<-read.csv(url(file_url1))ts_all_long<-ts_all_long％>％mutate(日期= as.Date(日期)) 

使用的图像:(v2.0.0)创建于2021-04-20 sup>

但是，我认为这样做实际上看起来会更好:

  ts_all_long％>％filter(Country.Region ==巴西")％&％ggplot(aes(x =日期，y =确认每日))+background_image(readJPEG("/home/johannes/Downloads/coronavirus-4972480_1920.jpg"))+geom_area(大小= 1，col =白色"，填充=#f08080"，alpha = 0.5) 

^{由 reprex软件包(v2.0.0)创建于2021-04-20 sup>}

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)

解决方案

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)}

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