將圖像插入到ggplot2

Question

是否可以在圖上的geom_line()下插入光柵圖像或pdf圖像？

我想快速地將數據繪製在之前計算的繪圖上，這需要很長時間才能生成，因爲它使用大量數據。

我通過這個example閱讀。然而，因爲它已經超過一歲了，我認爲現在可能有不同的方式。

Answer 1

嘗試?annotation_custom在ggplot2

例如，

library(png) 
library(grid) 
img <- readPNG(system.file("img", "Rlogo.png", package="png")) 
g <- rasterGrob(img, interpolate=TRUE) 

qplot(1:10, 1:10, geom="blank") + 
    annotation_custom(g, xmin=-Inf, xmax=Inf, ymin=-Inf, ymax=Inf) + 
    geom_point() 

Answer 2

只是增加從了不起Magick包的更新：

library(ggplot2) 
library(magick) 
library(here) # For making the script run without a wd 
library(magrittr) # For piping the logo 

# Make a simple plot and save it 
ggplot(mpg, aes(displ, hwy, colour = class)) + 
    geom_point() + 
    ggtitle("Cars") + 
    ggsave(filename = paste0(here("/"), last_plot()$labels$title, ".png"), 
     width = 5, height = 4, dpi = 300) 

# Call back the plot 
plot <- image_read(paste0(here("/"), "Cars.png")) 
# And bring in a logo 
logo_raw <- image_read("http://hexb.in/hexagons/ggplot2.png") 

# Scale down the logo and give it a border and annotation 
# This is the cool part because you can do a lot to the image/logo before adding it 
logo <- logo_raw %>% 
    image_scale("100") %>% 
    image_background("grey", flatten = TRUE) %>% 
    image_border("grey", "600x10") %>% 
    image_annotate("Powered By R", color = "white", size = 30, 
       location = "+10+50", gravity = "northeast") 

# Stack them on top of each other 
final_plot <- image_append(image_scale(c(plot, logo), "500"), stack = TRUE) 
# And overwrite the plot without a logo 
image_write(final_plot, paste0(here("/"), last_plot()$labels$title, ".png"))