在R中的mtext（）左侧添加一个点

Question

我想知道是否可以在points()的左侧插入mtext()？ 换句话说，有没有办法可以获得mtext()的 x，y ，这样我才能确定points()的正确位置出现？

这是我的R代码：

curve(dnorm(x),-3,3)
mtext(bquote(paste("Medium: ",bold('CT'[12])," = ", .(round(1/3,3)))),line=3)

Answer 1

如果您使用text代替mtext，则变得非常简单，因为您可以对文本和点使用x和y。

#Plot the curve
curve(dnorm(x),-3,3)

#Enable drawing outside the plot region
par(xpd = TRUE)

#STEP 3. Add text at certain x and y.
text(x = 0, y = 0.45, 
    bquote(paste("Medium: ",bold('CT'[12])," = ", .(round(1/3,3)))))

#Determine the width of the text you added  
text_width = strwidth( bquote(paste("Medium: ",bold('CT'[12])," = ", .(round(1/3,3)))) )

#Find out x poistion just left of the text.
#Since the text is centre aligned by default,
#you can subtract half the text_width to the x value
#that you had used to add text in STEP 3
#You may also add 10% extra space
points_x = (0 - text_width/2) - (0.1*text_width)

#Add a point just to the left of the text
points(x = points_x, y = 0.45, pch = 20, cex = 3)