如何添加不同大小和颜色的ggplot2字幕？

Question

我正在使用ggplot2来改善降水条件.

这是我想要实现的可重现的例子:

library(ggplot2)
library(gridExtra)
secu <- seq(1, 16, by=2)
melt.d <- data.frame(y=secu, x=LETTERS[1:8])
m <- ggplot(melt.d, aes(x=x, y=y)) +
  geom_bar(fill="darkblue") + 
  labs(x="Weather    stations", y="Accumulated Rainfall [mm]") +
  opts(axis.text.x=theme_text(angle=-45, hjust=0, vjust=1),
       title=expression("Rainfall"), plot.margin = unit(c(1.5, 1, 1, 1), "cm"),
       plot.title = theme_text(size = 25, face = "bold", colour = "black", vjust = 5))
z <- arrangeGrob(m, sub = textGrob("Location", x = 0, hjust = -3.5, vjust = -33, gp = gpar(fontsize = 18, col = "gray40"))) #Or guessing x and y with just option
z

我不知道如何避免在gjplot2上的hjust和vjust上使用猜测数字？是否有更好的方法来放置字幕(不只是使用\n,而是使用不同文本颜色和大小的字幕)？

我需要能够使用ggsave来获得pdf文件.

以下是两个相关问题:

在R的情节区域外添加脚注引用？

如何在R中添加字幕并更改ggplot图的字体大小？

谢谢你的帮助.

Answer 1

最新的ggplot2版本(即2.1.0.9000或更新版本)具有字幕和低于标题的字幕作为内置功能.这意味着你可以这样做:

library(ggplot2) # 2.1.0.9000+ 

secu <- seq(1, 16, by=2)
melt.d <- data.frame(y=secu, x=LETTERS[1:8])

m <-  ggplot(melt.d, aes(x=x, y=y))
m <- m + geom_bar(fill="darkblue", stat="identity")
m <- m + labs(x="Weather    stations", 
              y="Accumulated Rainfall [mm]",
              title="Rainfall",
              subtitle="Location")
m <- m + theme(axis.text.x=element_text(angle=-45, hjust=0, vjust=1)) 
m <- m + theme(plot.title=element_text(size=25, hjust=0.5, face="bold", colour="maroon", vjust=-1))
m <- m + theme(plot.subtitle=element_text(size=18, hjust=0.5, face="italic", color="black"))
m

Answer 2

忽略此答案 ggplot2版本2.2.0具有标题和副标题功能.请参阅下面的 @ hrbrmstr的答案.

您可以在其中使用嵌套atop函数expression来获得不同的大小.

编辑更新了ggplot2 0.9.3的代码

m <-  ggplot(melt.d, aes(x=x, y=y)) + 
     geom_bar(fill="darkblue", stat = "identity") + 
     labs(x="Weather    stations", y="Accumulated Rainfall [mm]") + 
     ggtitle(expression(atop("Rainfall", atop(italic("Location"), "")))) +
     theme(axis.text.x = element_text(angle=-45, hjust=0, vjust=1), 
     #plot.margin = unit(c(1.5, 1, 1, 1), "cm"), 
     plot.title = element_text(size = 25, face = "bold", colour = "black", vjust = -1))

Answer 3

从optsggplot 2 0.9.1开始,它似乎已被弃用,不再起作用.这对我来说对今天的最新版本有用:+ ggtitle(expression(atop("Top line", atop(italic("2nd line"), "")))).

Answer 4

将gbs添加到gtable并以这种方式制作一个花哨的标题并不太难,

library(ggplot2)
library(grid)
library(gridExtra)
library(magrittr)
library(gtable)

p <- ggplot() + 
  theme(plot.margin = unit(c(0.5, 1, 1, 1), "cm"))

lg <- list(textGrob("Rainfall", x=0, hjust=0, 
                    gp = gpar(fontsize=24, fontfamily="Skia", face=2, col="turquoise4")),
               textGrob("location", x=0, hjust=0, 
                        gp = gpar(fontsize=14, fontfamily="Zapfino", fontface=3, col="violetred1")),
           pointsGrob(pch=21, gp=gpar(col=NA, cex=0.5,fill="steelblue")))

margin <- unit(0.2, "line")
tg <- arrangeGrob(grobs=lg, layout_matrix=matrix(c(1,2,3,3), ncol=2),
                  widths = unit.c(grobWidth(lg[[1]]), unit(1,"null")),
                  heights = do.call(unit.c, lapply(lg[c(1,2)], grobHeight)) + margin)

grid.newpage()
ggplotGrob(p) %>%
  gtable_add_rows(sum(tg$heights), 0) %>%
  gtable_add_grob(grobs=tg, t = 1, l = 4)  %>%
  grid.draw()

Answer 5

此版本使用一个gtable功能.它允许标题中有两行文本.每行的文本,大小,颜色和字体可以独立设置.但是,该功能仅使用单个绘图面板修改绘图.

次要编辑:更新到ggplot2 v2.0.0

# The original plot
library(ggplot2)

secu <- seq(1, 16, by = 2)
melt.d <- data.frame(y = secu, x = LETTERS[1:8])

m <- ggplot(melt.d, aes(x = x, y = y)) + 
     geom_bar(fill="darkblue", stat = "identity") + 
     labs(x = "Weather    stations", y = "Accumulated Rainfall [mm]") + 
     theme(axis.text.x = element_text(angle = -45, hjust = 0, vjust = 1))


# The function to set text, size, colour, and face
plot.title = function(plot = NULL, text.1 = NULL, text.2 = NULL, 
   size.1 = 12,  size.2 = 12,
   col.1 = "black", col.2 = "black", 
   face.1 = "plain",  face.2 = "plain") {

library(gtable)
library(grid)

gt = ggplotGrob(plot)

text.grob1 = textGrob(text.1, y = unit(.45, "npc"), 
   gp = gpar(fontsize = size.1, col = col.1, fontface = face.1))
text.grob2 = textGrob(text.2,  y = unit(.65, "npc"), 
   gp = gpar(fontsize = size.2, col = col.2, fontface = face.2))

text = matrix(list(text.grob1, text.grob2), nrow = 2)
text = gtable_matrix(name = "title", grobs = text, 
   widths = unit(1, "null"), 
   heights = unit.c(unit(1.1, "grobheight", text.grob1) + unit(0.5, "lines"), unit(1.1,  "grobheight", text.grob2) + unit(0.5, "lines")))

gt = gtable_add_grob(gt, text, t = 2, l = 4)
gt$heights[2] = sum(text$heights)

class(gt) =  c("Title", class(gt))

gt
}

# A print method for the plot
print.Title <- function(x) {
   grid.newpage()   
   grid.draw(x)
}


# Try it out - modify the original plot
p = plot.title(m, "Rainfall", "Location", 
   size.1 = 20, size.2 = 15, 
   col.1 = "red", col.2 = "blue", 
   face.2 = "italic")

p