更改geom_text的默认“a”图例标签字符串本身 [英] Change geom_text's default "a" legend to label string itself

问题描述

与

解决方案

您可以更改图例键生成功能。这仍然需要一些人工干预，但可以说比使用grobs还要少。

  library（ggplot2）
 library （网格）
 
数据（虹膜）
虹膜$ abbrev = substr（虹膜$物种，1,2）
 
 oldK<  -  GeomText $ draw_key＃to稍后保存
 
＃定义新键
＃如果您手动添加颜色，然后添加颜色矢量
＃而不是`scales :: hue_pal（）（length（var）） `
 GeomText $ draw_key<  - 函数（数据，参数，大小，
 var = unique（iris $ abbrev），
 cols = scales :: hue_pal（）（length（var）） ）{
 
＃按照ggplot排序这些字母数字/或者因子水平
 txt<  -  if（is.factor（var））levels（var）else sort（var）
 txt<  -  txt [match（data $ color，cols）] 
 
 textGrob（txt，0.5，0.5，
 just =center，
 gp = gpar （col = alpha（data $ color，data $ alpha），
 fontfamily = data $ family，
 fontface = data $ fontface，
 fontsize = data $ size * .pt））
} 
 
 ggplot（data = iris，aes（ x = Sepal.Length，y = Sepal.Width，
 shape = Species，color = Species））+ 
 geom_text（aes（label = abbrev））
 
 
＃reset key 
 GeomText $ draw_key<  -  oldK 
  

Similarly to this question, I want to change the default "a" in the legend, but rather than removing it completely, I want to replace it with the labels themselves. That is, the first line of the legend should have a colored icon labeled "se" with the full name "setosa" on the right.

iris$abbrev = substr( iris$Species, 1, 2 )

ggplot(data = iris, aes(x = Sepal.Length, y=Sepal.Width, shape =
Species, colour = Species)) +  geom_text(aes(label = abbrev))

解决方案

You can change the legend key generating function. This still requires a bit of manual intervention, but arguably less than using the grobs.

library(ggplot2)
library(grid)

data(iris)
iris$abbrev = substr( iris$Species, 1, 2 )

oldK <- GeomText$draw_key # to save for later

# define new key
# if you manually add colours then add vector of colours 
# instead of `scales::hue_pal()(length(var))`
GeomText$draw_key <- function (data, params, size, 
                               var=unique(iris$abbrev), 
                               cols=scales::hue_pal()(length(var))) {

    # sort as ggplot sorts these alphanumerically / or levels of factor
    txt <- if(is.factor(var)) levels(var) else sort(var)
    txt <- txt[match(data$colour, cols)]

    textGrob(txt, 0.5, 0.5,  
             just="center", 
             gp = gpar(col = alpha(data$colour, data$alpha), 
                       fontfamily = data$family, 
                       fontface = data$fontface, 
                       fontsize = data$size * .pt))
}

ggplot(data=iris, aes(x=Sepal.Length, y=Sepal.Width, 
                      shape=Species, colour=Species)) +  
  geom_text(aes(label = abbrev))


# reset key
GeomText$draw_key <- oldK

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