Changing background color for a text annotation to increase contrast and visibility

问题

I'd like to change the background color for my annotate text so that it's green and covers up anything behind it (like the horizontal line in the example below). How do I do that?

ggplot() + 
  geom_hline(yintercept=0) + 
  annotate("text",x=0,y=0,label="Here is a line")

回答1:

Try geom_label instead:

ggplot() + 
  geom_hline(yintercept = 0) + 
  labs(x = "", y = "") +
  geom_label(aes(x = 0, y = 0, label = "Here is a line"), fill = "green")

回答2:

Building on this answer, but avoiding the use of geom_label() so that the label draws only once, not once for every row of plotted data (as correctly pointed out in this comment):

You can still use annotate(), which is the preferred approach for a one-off annotation, but use label instead of text as the geom.

Likewise you could supply geom="segment" to draw a line, etc...

ggplot() + 
  geom_hline(yintercept=0) + 
  annotate(geom="label",x=0,y=0,label="Here is a line", fill="green")

来源：https://stackoverflow.com/questions/39602828/changing-background-color-for-a-text-annotation-to-increase-contrast-and-visibil