在ggplot中的图形内添加自定义线

Question

我想在图中添加一些自定义线。

我制作该图的MWC为：

df_tra %>%
    filter(Theta_param==1, Int_dis=='Bench', Gamma_param==0.76, Rho_param==0) %>%
    ggplot(aes(x = Debt))+
    geom_line(aes(y = Gini_tra,  colour = "Gini Coeff."), size = 1.2, colour="blue") +
    xlab("Public Debt") +
    ylab("Wealth Inequality") +
    geom_hline(yintercept=1, linetype="dashed", color = "black")+
    geom_vline(xintercept = 0.02, linetype="dashed", 
               color = "black")+
    theme_minimal()+

在上面的代码中，我如何在图形中引入自定义线，其中这些线上方有一些文本：

例如，我打算做的事情应该看起来像这样：

Answer 1

根据OP评论进行了更新

首先，使用示例数据的两个不同选项。由于您未包含df_tra对象，因此您的MWC无法正常工作，我使用了annotate帮助中的mtcars数据集

1。注释

这是使用ggplot2库中的annotate的解决方案

ggplot(mtcars, aes(x = wt, y = mpg)) + 
  geom_point() + 
  annotate("text", x = 4, y = 25, label = "Some text") +
  annotate("segment", x = 3.45, xend = 4.25, y = 19.5, yend = 25,
       colour = "blue", arrow=arrow(ends = "last"))
# from arrow help:
# arrow(angle = 30, length = unit(0.25, "inches"),
#       ends = "last", type = "open")
# Arguments
# 
# angle 
# The angle of the arrow head in degrees (smaller numbers 
# produce narrower, pointier arrows). Essentially describes 
# the width of the arrow head.
# length    
# A unit specifying the length of the arrow head (from tip to base).
# ends  
# One of "last", "first", or "both", indicating which ends of the line
# to draw arrow heads.
# type  
# One of "open" or "closed" indicating whether the arrow head 
# should be a closed triangle.

在ends="last（默认）下，箭头的箭头位于x.end=和y.end=定义的点，在ends="first下，箭头的箭头位于{{ 1}}和x=。 y=显示两个箭头。

---

2。注释和geom_segment

其他选项将结合ends="both和annotate，如本post

中所述

geom_segment

3。你的情节

首先模拟数据

ggplot(mtcars, aes(x = wt, y = mpg)) + 
  geom_point() + 
  annotate("text", x = 4, y = 25, label = "Some text") +
  geom_segment(aes(x = 3.45, xend = 4.25, y = 19.5, yend = 25),
       colour = "blue", 
       arrow=arrow(ends = "last"))

使用x <- seq(-5,10,0.5) y <- 10*x^2 + 10*x - 100 df <- data.frame(x=x, y=y) 生成箭头来生成图的代码。我之所以选择此选项，是因为至少在我的计算机中，箭头看起来比annotate生成的箭头更好。

geom_segment

和情节