r - ggplot2 2.1.0 破坏了我的代码？次要变换轴现在显示不正确

Question

前段时间，我询问了在 ggplot 中添加二次变换 x 轴的问题，Nate Pope 提供了ggplot2 中描述的出色解决方案：在 plot 顶部添加二次变换 x 轴。

该解决方案对我来说效果很好，我返回它希望它适用于一个新项目。不幸的是，该解决方案在最新版本的 ggplot2 中无法正常工作。现在，运行完全相同的代码会导致轴标题的“剪切”，以及刻度线和标签的重叠。这是一个示例，问题以蓝色突出显示：

可以使用以下代码复制此示例（这是 Nate Pope 之前出色工作的代码的精确副本）：

library(ggplot2)
library(gtable)
library(grid)

LakeLevels<-data.frame(Day=c(1:365),Elevation=sin(seq(0,2*pi,2*pi/364))*10+100)

## 'base' plot
p1 <- ggplot(data=LakeLevels) + geom_line(aes(x=Elevation,y=Day)) + 
  scale_x_continuous(name="Elevation (m)",limits=c(75,125)) +
  ggtitle("stuff") +
  theme(legend.position="none", plot.title=element_text(hjust=0.94, margin = margin(t = 20, b = -20)))

## plot with "transformed" axis
p2<-ggplot(data=LakeLevels)+geom_line(aes(x=Elevation, y=Day))+
  scale_x_continuous(name="Elevation (ft)", limits=c(75,125),
                     breaks=c(90,101,120),
                     labels=round(c(90,101,120)*3.24084) ## labels convert to feet
  )

## extract gtable
g1 <- ggplot_gtable(ggplot_build(p1))
g2 <- ggplot_gtable(ggplot_build(p2))

## overlap the panel of the 2nd plot on that of the 1st plot
pp <- c(subset(g1$layout, name=="panel", se=t:r))

g <- gtable_add_grob(g1, g2$grobs[[which(g2$layout$name=="panel")]], pp$t, pp$l, pp$b, 
                     pp$l)

g <- gtable_add_grob(g1, g1$grobs[[which(g1$layout$name=="panel")]], pp$t, pp$l, pp$b, pp$l)

## steal axis from second plot and modify
ia <- which(g2$layout$name == "axis-b")
ga <- g2$grobs[[ia]]
ax <- ga$children[[2]]

## switch position of ticks and labels
ax$heights <- rev(ax$heights)
ax$grobs <- rev(ax$grobs)
ax$grobs[[2]]$y <- ax$grobs[[2]]$y - unit(1, "npc") + unit(0.15, "cm")

## modify existing row to be tall enough for axis
g$heights[[2]] <- g$heights[g2$layout[ia,]$t]

## add new axis
g <- gtable_add_grob(g, ax, 2, 4, 2, 4)

## add new row for upper axis label
g <- gtable_add_rows(g, g2$heights[1], 1)
g <- gtable_add_grob(g, g2$grob[[6]], 2, 4, 2, 4)

# draw it
grid.draw(g)

运行上面的代码会导致两个关键问题，我正在尝试解决：

1)如何调整添加到绘图顶部的 x 轴以解决“剪裁”和重叠问题？

2）如何在最终情节中包含ggtitle("stuff")添加到第一个情节p1的内容？

我整个下午都在尝试解决这些问题，但似乎无法解决它们。任何帮助深表感谢。谢谢！

score 5 · Accepted Answer

更新到 ggplot2 v 2.2.1，但更易于使用sec.axis- 请参见此处

原来的

从版本 2.1.0 开始，移动轴ggplot2变得更加复杂。该解决方案借鉴了旧解决方案和cowplot包中代码的代码。

关于您的第二个问题，为“Stuff”标题构建单独的文本 grob 更容易（而不是处理ggtitle其边距）。

library(ggplot2) #v 2.2.1
library(gtable)  #v 0.2.0
library(grid)

LakeLevels <- data.frame(Day = c(1:365), Elevation = sin(seq(0, 2*pi, 2 * pi/364)) * 10 + 100)

## 'base' plot
p1 <- ggplot(data = LakeLevels) + 
  geom_path(aes(x = Elevation, y = Day)) + 
  scale_x_continuous(name = "Elevation (m)", limits = c(75, 125)) + 
  theme_bw() 

## plot with "transformed" axis
p2 <- ggplot(data = LakeLevels) +
  geom_path(aes(x = Elevation, y = Day))+
  scale_x_continuous(name = "Elevation (ft)", limits = c(75, 125),
                     breaks = c(80, 90, 100, 110, 120),
                     labels = round(c(80, 90, 100, 110, 120) * 3.28084)) +   ## labels convert to feet
theme_bw()

## Get gtable
g1 <- ggplotGrob(p1)    
g2 <- ggplotGrob(p2)

## Get the position of the plot panel in g1
pp <- c(subset(g1$layout, name == "panel", se = t:r))

# Title grobs have margins. 
# The margins need to be swapped.
# Function to swap margins - 
# taken from the cowplot package:
# https://github.com/wilkelab/cowplot/blob/master/R/switch_axis.R
vinvert_title_grob <- function(grob) {
  heights <- grob$heights
  grob$heights[1] <- heights[3]
  grob$heights[3] <- heights[1]
  grob$vp[[1]]$layout$heights[1] <- heights[3]
  grob$vp[[1]]$layout$heights[3] <- heights[1]

  grob$children[[1]]$hjust <- 1 - grob$children[[1]]$hjust 
  grob$children[[1]]$vjust <- 1 - grob$children[[1]]$vjust 
  grob$children[[1]]$y <- unit(1, "npc") - grob$children[[1]]$y
  grob
}

# Copy "Elevation (ft)" xlab from g2 and swap margins
index <- which(g2$layout$name == "xlab-b")
xlab <- g2$grobs[[index]]
xlab <- vinvert_title_grob(xlab)

# Put xlab at the top of g1
g1 <- gtable_add_rows(g1, g2$heights[g2$layout[index, ]$t], pp$t-1)
g1 <- gtable_add_grob(g1, xlab, pp$t, pp$l, pp$t, pp$r, clip = "off", name="topxlab")

# Get "feet" axis (axis line, tick marks and tick mark labels) from g2
index <- which(g2$layout$name == "axis-b")
xaxis <- g2$grobs[[index]]

# Move the axis line to the bottom (Not needed in your example)
xaxis$children[[1]]$y <- unit.c(unit(0, "npc"), unit(0, "npc"))

# Swap axis ticks and tick mark labels
ticks <- xaxis$children[[2]]
ticks$heights <- rev(ticks$heights)
ticks$grobs <- rev(ticks$grobs)

# Move tick marks
ticks$grobs[[2]]$y <- ticks$grobs[[2]]$y - unit(1, "npc") + unit(3, "pt")

# Sswap tick mark labels' margins
ticks$grobs[[1]] <- vinvert_title_grob(ticks$grobs[[1]])

# Put ticks and tick mark labels back into xaxis
xaxis$children[[2]] <- ticks

# Add axis to top of g1
g1 <- gtable_add_rows(g1, g2$heights[g2$layout[index, ]$t], pp$t)
g1 <- gtable_add_grob(g1, xaxis, pp$t+1, pp$l, pp$t+1, pp$r, clip = "off", name = "axis-t")

# Add "Stuff" title
titleGrob = textGrob("Stuff", x = 0.9, y = 0.95, gp = gpar(cex = 1.5, fontface = "bold"))
g1 <- gtable_add_grob(g1, titleGrob, pp$t+2, pp$l, pp$t+2, pp$r, name = "Title")

# Draw it
grid.newpage()
grid.draw(g1)

score 0 · Accepted Answer

如上所述，您可以使用sec_axis或dup_axis。

library(ggplot2)

LakeLevels <- data.frame(Day = c(1:365), 
                         Elevation = sin(seq(0, 2*pi, 2 * pi/364)) * 10 + 100)

ggplot(data = LakeLevels) + 
  geom_path(aes(x = Elevation, y = Day)) + 
  scale_x_continuous(name = "Elevation (m)", limits = c(75, 125),
                     sec.axis = sec_axis(trans = ~ . * 3.28084, name = "Elevation (ft)"))

ggplot2版本 3.1.1

score 0 · Accepted Answer

经过一番思考，我确认问题 #1 源于对 ggplot2 最新版本的更改，并且我还提出了一个临时解决方法 - 安装旧版本的 ggplot2。

在安装旧版本的 R 包以安装 ggplot2 1.0.0 之后，我使用安装 ggplot2 1.0.0

packageurl <- "http://cran.r-project.org/src/contrib/Archive/ggplot2/ggplot2_1.0.0.tar.gz"
install.packages(packageurl, repos=NULL, type="source")

我验证了

packageDescription("ggplot2")$Version

然后，重新运行上面发布的确切代码，我能够生成一个正确显示添加的 x 轴的图：

这显然不是一个非常令人满意的答案，但它至少可以工作，直到有人比我更聪明才能解释为什么这种方法在最近版本的 ggplot2 中不起作用。:)

所以上面的问题 #1 已经解决了。 我还没有从上面解决问题#2，所以如果有任何见解，我将不胜感激。

r - ggplot2 2.1.0 破坏了我的代码？次要变换轴现在显示不正确

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