如何更改geom_text（）在绘图区域外的字体大小？

Question

我想对一个情节进行注释，我希望这个音符在情节区域之外。我找到了this solution，它可以在绘图区域外添加注释，但我无法弄清楚如何更改标签的外观（最重要的是，为了我的目的，字体大小）。

以下是上述解决方案的最小示例：

library (ggplot2)
library(grid)

df=data.frame(y=c("dog1","dog2","dog3"),x=c(12,10,14),n=c(5,15,20))
p <- ggplot(df, aes(x,y)) + geom_point()

# Add the annotation
p <- p + geom_text(aes(label = "Hello World!", x = 0, y = 0), vjust = 2, hjust = 1)

# Code to override clipping
gt <- ggplot_gtable(ggplot_build(p))
gt$layout$clip[gt$layout$name == "panel"] <- "off"
grid.draw(gt)

理想情况下，音符会位于左下角。

Answer 1

library (ggplot2)
library(grid)

df=data.frame(y=c("dog1","dog2","dog3"),x=c(12,10,14),n=c(5,15,20))
p <- ggplot(df, aes(x,y)) + geom_point()

# Add the annotation
p <- p + geom_text(size=8, colour="red", aes(label = "Hello World!", x = 0, y = 0), vjust = 2.5, hjust = 1)

# Code to override clipping
gt <- ggplot_gtable(ggplot_build(p))
gt$layout$clip[gt$layout$name == "panel"] <- "off"
grid.draw(gt)