While adding a semi transparent layer to background image in r getting Error: Invalid input: date_trans works with objects of class Date only

Question

我正在尝试在 r 图中向 背景图像 添加一个 半透明覆盖黑色层 。它通过使用 annotate 工作并从以下位置获得解决方案：

问题：半透明层没有完全从左到右延伸到绘图图像上。

如果我尝试使用 xmin = -Inf, xmax = Inf 那么它会由于日期刻度 x 轴而出错。

那么如何用图层覆盖整个图像？

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))

使用的图像：https://github.com/johnsnow09/covid19-df_stack-code/blob/a00c8820363f2163837d24f801f7c5b85167e0aa/coronavirus-4972480_1920.jpg

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)

如果我在 xscale 上将其从 -Inf 扩展到 Inf：annotate("rect", xmin = min(ts_all_long$date), xmax = max(ts_all_long$date), ymin = -Inf, ymax = Inf, fill = "black", alpha = 0.3) +

然后它给出错误 错误：无效输入：date_trans 仅适用于 class 日期的对象

Answer 1

问题是 scales::date_trans() 转换不能很好地处理数字输入。我通过手动构建无限日期找到了这个问题的 workaround。下面是标准数据集的示例：

library(ggplot2)

ggplot(economics, aes(date, unemploy)) +
  geom_line() +
  annotate("rect", xmin = -Inf, xmax = Inf,
           ymin = -Inf, ymax = Inf, fill = "black", alpha = 0.5)
#> Error: Invalid input: date_trans works with objects of class Date only

# Manually constructing infinite dates
ggplot(economics, aes(date, unemploy)) +
  geom_line() +
  annotate("rect", 
           xmin = structure(-Inf, class = "Date"), 
           xmax = structure(Inf, class = "Date"),
           ymin = -Inf, ymax = Inf, fill = "black", alpha = 0.5)

^{由 reprex package (v1.0.0)}

于 2021-04-20 创建

I've argued 在此之前，理想情况下，scales 包中的日期和时间转换应该更灵活一些以处理此类情况。

While adding a semi transparent layer to background image in r getting Error: Invalid input: date_trans works with objects of class Date only

While adding a semi transparent layer to background image in r getting Error: Invalid input: date_trans works with objects of class Date only

r

ggplot2

annotations

background-image

transparency