在ggplot2中的绘图区域外添加文本

Question

我正在尝试创建以下情节，我想在情节中添加一些其他说明，以使读者了解该情节的一些重要特征。

我正在尝试将4个文本描述（希望带有线段）添加到图形中。

ggplot是否可行？还是应该寻找其他软件包来做到这一点？

线的长度与点的散布有关，我不介意手动为这些线添加固定宽度的线，但是看看是否有办法使线的长度相关也很酷分散（但实际上并不重要！）。

我正在绘制一个模型与另一个模型的预测概率。

我有一个名为x的数据框

ggplot代码：

ggplot(x, aes(x=mod1, y=mod2, colour = actual)) + 
  geom_point(alpha = 1) +
  geom_density_2d() +
  stat_density_2d(aes(fill = ..level..), geom="polygon", alpha = 1) +
  labs(x = "plot1 results", subtitle = "--------------- subtitle which can be quite long like this -------------------", y = "plot2 results", title = "title") +
  theme_bw(base_size = 11, base_family = "") +
  theme(aspect.ratio = 1) +
  scale_color_manual(values=c("yellow", "grey"))

数据：

structure(list(mod1 = c(0.0428680343284435, 0.846016555762155, 
0.326787531886571, 0.553755029639909, 0.687879627696911, 0.0960930400203601, 
0.744828994271728, 0.540002328947346, 0.220881375043177, 0.0702872626691926, 
0.326427351123072, 0.242150667845905, 0.0585994813808256, 0.0476546237354429, 
0.677024473452915, 0.141965306592508, 0.580238736830929, 0.209089243871524, 
0.202588588164632, 0.462602376730863, 0.170047796107216, 0.0599183763024999, 
0.144128948353236, 0.704983877871062, 0.148981617804389, 0.0259100317297817, 
0.070919748619838, 0.847120835339521, 0.280625159241402, 0.241346727659237, 
0.285528700584795, 0.522832128634093, 0.0495932506050149, 0.191222810970403, 
0.848539280298263, 0.460823513872965, 0.297519579850422, 0.299706327222228, 
0.29118588708967, 0.569263883004122, 0.814633900535549, 0.268597010973285, 
0.583651002250045, 0.0771418703083737, 0.272577428138581, 0.0652980769011686, 
0.0645563141023351, 0.185751367095499, 0.163771389063719, 0.922377554059713, 
0.118440921292355, 0.601015657502687, 0.458036991708823, 0.706976353965206, 
0.557104373519309, 0.336600458082119, 0.365573066188997, 0.349695386601579, 
0.885005310870269, 0.340463030723538, 0.646538075407289, 0.347697108751173, 
0.23887463827597, 0.222397529338268, 0.261741960415693, 0.255160177543014, 
0.394003003413919, 0.350059479442216, 0.443055385407801, 0.999532291288415, 
0.025735898423369, 0.369031728988488, 0.105252031223466, 0.233622390662318, 
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0.138004937708603, 0.111975864093794, 0.818441921329778, 0.0392858886896277, 
0.593233184537478, 0.186525732878499, 0.467999992773845, 0.653350287632996, 
0.550997098851144, 0.525885581162108, 0.98809473982989, 0.304496141867713, 
0.233695105089987, 0.168798462655651, 0.276530329800917, 0.0258753799208103, 
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0.447224424542321, 0.545195283609091, 0.620149367286776, 0.143021628347417, 
0.365110938943906), actual = structure(c(1L, 1L, 1L, 1L, 1L, 
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1L, 1L, 2L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 2L, 1L, 1L, 1L, 1L, 1L, 
1L, 1L, 1L, 2L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 2L, 1L, 1L, 1L, 
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