当ggplot2中有多个图有一些图例而其他图没有图例时,可以对齐多个图

Question

我使用此处指示的方法来对齐共享相同横坐标的图形.

但是当我的一些图表有一个传奇而其他图表没有传说时,我无法使它工作.

这是一个例子:

library(ggplot2)
library(reshape2)
library(gridExtra)

x = seq(0, 10, length.out = 200)
y1 = sin(x)
y2 = cos(x)
y3 = sin(x) * cos(x)

df1 <- data.frame(x, y1, y2)
df1 <- melt(df1, id.vars = "x")

g1 <- ggplot(df1, aes(x, value, color = variable)) + geom_line()
print(g1)

df2 <- data.frame(x, y3)
g2 <- ggplot(df2, aes(x, y3)) + geom_line()
print(g2)

gA <- ggplotGrob(g1)
gB <- ggplotGrob(g2)
maxWidth <- grid::unit.pmax(gA$widths[2:3], gB$widths[2:3])
gA$widths[2:3] <- maxWidth
gB$widths[2:3] <- maxWidth
g <- arrangeGrob(gA, gB, ncol = 1)
grid::grid.newpage()
grid::grid.draw(g)

使用此代码,我得到以下结果:

我想要的是让x轴对齐,缺少的图例由空格填充.这可能吗？

编辑:

提出的最优雅的解决方案是Sandy Muspratt的解决方案.

我实现了它,它可以很好地使用两个图表.

然后我尝试了三个,具有不同的图例大小,它不再起作用了:

library(ggplot2)
library(reshape2)
library(gridExtra)

x = seq(0, 10, length.out = 200)
y1 = sin(x)
y2 = cos(x)
y3 = sin(x) * cos(x)
y4 = sin(2*x) * cos(2*x)

df1 <- data.frame(x, y1, y2)
df1 <- melt(df1, id.vars = "x")

g1 <- ggplot(df1, aes(x, value, color = variable)) + geom_line()
g1 <- g1 + theme_bw()
g1 <- g1 + theme(legend.key = element_blank())
g1 <- g1 + ggtitle("Graph 1", subtitle = "With legend")

df2 <- data.frame(x, y3)
g2 <- ggplot(df2, aes(x, y3)) + geom_line()
g2 <- g2 + theme_bw()
g2 <- g2 + theme(legend.key = element_blank())
g2 <- g2 + ggtitle("Graph 2", subtitle = "Without legend")

df3 <- data.frame(x, y3, y4)
df3 <- melt(df3, id.vars = "x")

g3 <- ggplot(df3, aes(x, value, color = variable)) + geom_line()
g3 <- g3 + theme_bw()
g3 <- g3 + theme(legend.key = element_blank())
g3 <- g3 + scale_color_discrete("This is indeed a very long title")
g3 <- g3 + ggtitle("Graph 3", subtitle = "With legend")

gA <- ggplotGrob(g1)
gB <- ggplotGrob(g2)
gC <- ggplotGrob(g3)

gB = gtable::gtable_add_cols(gB, sum(gC$widths[7:8]), 6)

maxWidth <- grid::unit.pmax(gA$widths[2:5], gB$widths[2:5], gC$widths[2:5])
gA$widths[2:5] <- maxWidth
gB$widths[2:5] <- maxWidth
gC$widths[2:5] <- maxWidth

g <- arrangeGrob(gA, gB, gC, ncol = 1)
grid::grid.newpage()
grid::grid.draw(g)

这导致下图:

我在这里以及关于这个主题的其他问题中找到的答案的主要问题是,人们在向量中"玩"了很多myGrob$widths而没有实际解释为什么他们这样做.我看到人们修改myGrob$widths[2:5]其他人myGrob$widths[2:3],我找不到任何文档来解释这些列是什么.

我的目标是创建一个通用函数,例如:

AlignPlots <- function(...) {
  # Retrieve the list of plots to align
  plots.list <- list(...)

  # Initialize the lists
  grobs.list <- list()
  widths.list <- list()

  # Collect the widths for each grob of each plot
  max.nb.grobs <- 0
  longest.grob <- NULL
  for (i in 1:length(plots.list)){
    if (i != length(plots.list)) {
      plots.list[[i]] <- plots.list[[i]] + theme(axis.title.x = element_blank())
    }

    grobs.list[[i]] <- ggplotGrob(plots.list[[i]])
    current.grob.length <- length(grobs.list[[i]])
    if (current.grob.length > max.nb.grobs) {
      max.nb.grobs <- current.grob.length
      longest.grob <- grobs.list[[i]]
    }

    widths.list[[i]] <- grobs.list[[i]]$widths[2:5]
  }

  # Get the max width
  maxWidth <- do.call(grid::unit.pmax, widths.list)

  # Assign the max width to each grob
  for (i in 1:length(grobs.list)){
    if(length(grobs.list[[i]]) < max.nb.grobs) {
      grobs.list[[i]] <- gtable::gtable_add_cols(grobs.list[[i]],
                                                 sum(longest.grob$widths[7:8]),
                                                 6)
    }
    grobs.list[[i]]$widths[2:5] <- as.list(maxWidth)
  }

  # Generate the plot
  g <- do.call(arrangeGrob, c(grobs.list, ncol = 1))

  return(g)
}

Answer 1

扩展@ Axeman的答案,您cowplot无需draw_plot直接使用即可完成所有这些操作.基本上,您只需将图表分为两列 - 一个用于绘图本身,另一个用于图例 - 然后将它们放在一起.请注意,因为g2没有图例,我使用空ggplot对象将该图例的位置保存在图例列中.

library(cowplot)

theme_set(theme_minimal())

plot_grid(
  plot_grid(
    g1 + theme(legend.position = "none")
    , g2
    , g3 + theme(legend.position = "none")
    , ncol = 1
    , align = "hv")
  , plot_grid(
    get_legend(g1)
    , ggplot()
    , get_legend(g3)
    , ncol =1)
  , rel_widths = c(7,3)
  )

给

在我看来,这里的主要优点是能够根据每个子图的需要设置和跳过图例.

值得注意的是,如果所有图都有图例,请plot_grid为您处理对齐:

plot_grid(
  g1
  , g3
  , align = "hv"
  , ncol = 1
)

给

只有缺少的传奇才会g2导致问题.

因此,如果您添加虚拟图例g2并隐藏它的元素,您可以plot_grid为您完成所有对齐,而不必担心rel_widths如果更改输出的大小,请手动调整

plot_grid(
  g1
  , g2 + 
      geom_line(aes(color = "Test")) +
      scale_color_manual(values = NA) +
      theme(legend.text = element_blank()
            , legend.title = element_blank())
  , g3
  , align = "hv"
  , ncol = 1
)

给

这也意味着您可以轻松拥有多个列,但仍保持绘图区域相同.简单地, ncol = 1从上面删除产生一个有2列的图,但仍然正确间隔(虽然你需要调整宽高比使其可用):

正如@baptiste建议的那样,您还可以移动图例,使它们全部对齐到图的"图例"部分的左侧,方法是添加theme(legend.justification = "left")带有图例的图(或theme_set全局设置),如下所示:

plot_grid(
  g1 +
    theme(legend.justification = "left")
  , 
  g2 + 
    geom_line(aes(color = "Test")) +
    scale_color_manual(values = NA) +
    theme(legend.text = element_blank()
          , legend.title = element_blank())
  , g3 +
    theme(legend.justification = "left")
  , align = "hv"
  , ncol = 1
)

给

Answer 2

现在可能有更简单的方法来执行此操作,但您的代码并没有太大的错误.

确保gA中第2列和第3列的宽​​度与gB中的宽度相同后,检查两个gtables的宽度:gA$widths和gB$widths.您会注意到gA gtable在gB gtable中有两个不存在的列,即宽度7和8.使用该gtable函数gtable_add_cols()将列添加到gB gtable:

gB = gtable::gtable_add_cols(gB, sum(gA$widths[7:8]), 6)

然后继续arrangeGrob()....

编辑:更一般的解决方案

包egg(在github上可用)是实验性且易碎的,但与您修改的一组图很好地配合.

# install.package(devtools)
devtools::install_github("baptiste/egg")

library(egg)
grid.newpage()
grid.draw(ggarrange(g1,g2,g3, ncol = 1))

Answer 3

由于这个和那个,在发表的评论(然后删除),我想出了下面的通用解决方案.

我喜欢Sandy Muspratt的回答,鸡蛋包装似乎以非常优雅的方式完成工作,但由于它是"实验性和脆弱性",我更喜欢使用这种方法:

#' Vertically align a list of plots.
#' 
#' This function aligns the given list of plots so that the x axis are aligned.
#' It assumes that the graphs share the same range of x data.
#'
#' @param ... The list of plots to align.
#' @param globalTitle The title to assign to the newly created graph.
#' @param keepTitles TRUE if you want to keep the titles of each individual
#' plot.
#' @param keepXAxisLegends TRUE if you want to keep the x axis labels of each
#' individual plot. Otherwise, they are all removed except the one of the graph
#' at the bottom.
#' @param nb.columns The number of columns of the generated graph.
#'
#' @return The gtable containing the aligned plots.
#' @examples
#' g <- VAlignPlots(g1, g2, g3, globalTitle = "Alignment test")
#' grid::grid.newpage()
#' grid::grid.draw(g)
VAlignPlots <- function(...,
                       globalTitle = "",
                       keepTitles = FALSE,
                       keepXAxisLegends = FALSE,
                       nb.columns = 1) {
  # Retrieve the list of plots to align
  plots.list <- list(...)

  # Remove the individual graph titles if requested
  if (!keepTitles) {
    plots.list <- lapply(plots.list, function(x) x <- x + ggtitle(""))
    plots.list[[1]] <- plots.list[[1]] + ggtitle(globalTitle)
  }

  # Remove the x axis labels on all graphs, except the last one, if requested
  if (!keepXAxisLegends) {
    plots.list[1:(length(plots.list)-1)] <-
      lapply(plots.list[1:(length(plots.list)-1)],
             function(x) x <- x + theme(axis.title.x = element_blank()))
  }

  # Builds the grobs list
  grobs.list <- lapply(plots.list, ggplotGrob)

  # Get the max width
  widths.list <- do.call(grid::unit.pmax, lapply(grobs.list, "[[", 'widths'))

  # Assign the max width to all grobs
  grobs.list <- lapply(grobs.list, function(x) {
    x[['widths']] = widths.list
    x})

  # Create the gtable and display it
  g <- grid.arrange(grobs = grobs.list, ncol = nb.columns)
  # An alternative is to use arrangeGrob that will create the table without
  # displaying it
  #g <- do.call(arrangeGrob, c(grobs.list, ncol = nb.columns))

  return(g)
}

Answer 4

一个技巧是在没有任何图例的情况下绘制和对齐图形,然后将图例分别绘制在旁边.cowplot具有便捷功能,可以快速从绘图中获取图例,并plot_grid允许自动对齐.

library(cowplot)
theme_set(theme_grey())

l <- get_legend(g1)
ggdraw() +
  draw_plot(plot_grid(g1 + theme(legend.position = 'none'), g2, ncol = 1, align = 'hv'),
            width = 0.9) +
  draw_plot(l, x = 0.9, y = 0.55, width = 0.1, height = 0.5)

Answer 5

patchworkThomas Lin Pedersen 的软件包可以自动完成所有任务：

##devtools::install_github("thomasp85/patchwork")
library(patchwork)
g1 + g2 + plot_layout(ncol = 1)

几乎没有比这更容易的了。