如何在ggplot facet wrap标签中使用不同的字体大小？

Question

我想在facet wrap的标签中创建两种不同大小的文本.

例如:

• 物种X(14号)
• 总捕获量(n = 133)(12号)

test <- read.csv(paste0(path, "Costello Artvgl2 for Stack.csv"), sep = ";", dec = ",", header = T)

str(test)


test$Wert <- factor(test$Wert, levels = c("one","two","three","four","five","six")) 


test$Sampling.site <- factor(test$Sampling.site, levels = c("Species X Area T","Species Y Area T","Species X Area A","Species Y Area B","Species X Area B","Species Y Area C"))


levels(test$Sampling.site) <-  c("Species X\nTotal catch (n=133)", "Species Y\nTotal catch (n=185)", "Species X\nSampling area A (n=57)", "Species Y\nSampling area B (n=122)",
                             "Species X\nSampling area B (n=76)",  "Species Y\nSampling area C (n=63)")

theme_new <- function(base_size = 12, base_family = base_family){
theme_bw(base_size = base_size) %+replace%
theme(
  axis.text.x =       element_text(size = 8 ),
  axis.text.y =       element_text(size = 8 ),
  axis.title.x =        element_text(size = 12, vjust = 0.01),
  axis.title.y =        element_text(size = 12, vjust = 0.9, angle = 90),

  plot.title =        element_text(size = 10, face = "bold"),

  legend.key=         element_rect(colour= NA, fill =NA, size = 0.5),
  legend.key.size =   unit(1, "lines"),
  legend.text =       element_text(size = 8),
  legend.title =      element_blank(),

  strip.background =  element_rect(fill = NA, colour = NA), 
  strip.text =        element_text(size = 8, face = "bold",hjust = 0.5, vjust = 0.9),

  panel.background =  element_rect(fill = "white"), 
  panel.border =      element_rect(fill = NA, colour="black"), 
  panel.grid.major =  element_blank(),
  panel.grid.minor =  element_blank(),
  panel.margin =      unit(1, "lines")

)
}

ggplot(test, aes(Fi, Pi),group=Wert)+
geom_point(aes(colour = factor(Wert),shape = factor(Wert)),size=3)      +                         
  scale_shape_manual(values=c(20,18,19,15,16,17))+                    
  scale_x_continuous(limits=c(0, 1),breaks=c(0,0.2,0.4,0.6,0.8,1.0))+     
  scale_colour_brewer(type = "qual", palette = "Paired")+
  scale_y_continuous(limits=c(0, 100),breaks=c(0,20,40,60,80,100))+        
  labs(x = "Frequency of occurrence", y = "Prey-specific abundance [%]")+ 
  facet_wrap(~Sampling.site,scales = "free",ncol = 2) +
  theme_new()

有没有可能意识到这一点？

Answer 1

下面的解决方案是一个hack,因为它使用上标(或下标)来获得facet标签的第二行的较小字体大小.我不确定如何更好地控制标签尺寸而不需要直接操纵条带凹凸,尽管可能有一种方法来编写一个labeller函数来完成它.

我们将使用内置mtcars数据框作为示例.首先,我们将添加将用于刻面和标注的列.我们将cyl面对,但我们希望标签的第一行显示该facet的柱面数,第二行显示该facet中的数据点数.为此,我们将创建两个新列mtcars,调用Label1并Label2用于创建构面标签的每一行.我们将通过这两列来获取图中我们想要的标签.(Label3类似于Label2,但使用下标而不是上标;这仅在您想要更改从第二行底部到绘图面板顶部的距离时才有意义.)

Label1并且Label2是文本字符串,但它们是表达式的形式,因此我们可以label_parsed在创建绘图时使用较小的下标文本.

library(ggplot2)
library(dplyr)
library(grid)

mtcars.new = mtcars %>% group_by(cyl) %>% 
  summarise(Label1=paste0("bold(Cylinders:~", unique(cyl),")"),
            Label2=paste0("bold(NULL[Count:~", length(cyl),"])"),
            Label3=paste0("bold(NULL^{Count:~", length(cyl),"})")) %>%
  full_join(mtcars)

现在我们可以创建情节了.切面Label1并Label2给我们两行.因为我们为其创建了一个下标表达式Label2,所以当我们label_parsed用来标注facet 时,它会以较小的字体呈现.Label2相对而言Label1,我更喜欢相对较大,但是没有办法用这种(hacky)方法来控制它.此外,虽然element_text有一个lineheight参数,ggplot似乎并不尊重它.因此,我手动重置条带标签的线高,以减少两个标签之间的空间.

p = ggplot(mtcars.new, aes(wt, mpg)) +
  geom_point() +
  facet_grid(. ~ Label1 + Label2, labeller=label_parsed) +
  theme_bw() +
  theme(strip.background=element_rect(fill=NA, color=NA),
        strip.text=element_text(size=12))

g <- ggplotGrob(p)
g$heights[[3]] = unit(0.5,"lines")

grid.draw(g)