增加ggplot2中axis.title和axis.text之间的空间（版本> = 0.9.0）

Question

I am currently using the latest version of ggplot2 from github.

In version 0.8.9 I could do the following to increase space between axis.title and axis.text:

Before:

ggplot(diamonds, aes(clarity)) + geom_bar() + opts(
    axis.title.x = theme_text(vjust=-1.1)
)

Fix:

ggplot(diamonds, aes(clarity)) + geom_bar() + opts(
    axis.title.x = theme_text(vjust=-1.1),
    plot.margin = unit(c(1, 1, 0.8, 0.5), "lines")
)

and the axis.title becomes fully visible.

In the latest github version of ggplot2 plot.margin has no effect on axis.title:

ggplot(diamonds, aes(clarity)) + geom_bar() + opts(
    axis.title.x = theme_text(vjust=-0.2),
    plot.margin = unit(c(1, 1, 2, 0.5), "lines"))

(notice the increased bottom margin - I can't get plot.background to work in the latest development version)

It seems that 0.8.9 allows axis.title to move over the extra space created by plot.margin, but this is not allowed in the latest development version.

Is there a new way to accomplish this task (or a quick fix for it) in the latest development version?

Any help appreciated.

Answer 1

How to do it properly

Use the margin attribute of element_text for axis.title in theme . I use different margins for x and y since I rotate the y title to horizontal (making it easier to read).

library(ggplot2)
library(gridExtra)

ggplot(diamonds, aes(clarity)) +
    geom_bar() +
    theme(
        axis.title.x = element_text(margin = unit(c(3, 0, 0, 0), "mm")),
        axis.title.y = element_text(margin = unit(c(0, 3, 0, 0), "mm"), angle = 0)
    )

Old hack

opts and theme_text are no longer supported by ggplot. My quick and dirty solution is therefore to just add line breaks at the start or end of the title. It might be ugly but gets the job done with a minimal effort.

ggplot(diamonds, aes(clarity)) +
    geom_bar() +
    xlab("\nClarity") + ylab("Count\n")

Answer 2

I am closing the question as the fix I made seems to hold for now (see below).

I found the following code in plot-render.r:64:

xlab_height <- grobHeight(xlabel) + 
  if (is.null(labels$x)) unit(0, "lines") else unit(0.5, "lines")
plot_table <- gtable_add_rows(plot_table, xlab_height)
plot_table <- gtable_add_grob(plot_table, xlabel, name = "xlab", 
  l = panel_dim$l, r = panel_dim$r, t = -1)

ylab_width <- grobWidth(ylabel) + 
  if (is.null(labels$y)) unit(0, "lines") else unit(0.5, "lines")
plot_table <- gtable_add_cols(plot_table, ylab_width, pos = 0)
plot_table <- gtable_add_grob(plot_table, ylabel, name = "ylab",
  l = 1, b = panel_dim$b, t = panel_dim$t)

which I changed to:

xlab_height <- grobHeight(xlabel) + 
  if (is.null(labels$x)) unit(0, "lines") else unit(0.5, "lines")
plot_table <- gtable_add_rows(plot_table, xlab_height)
plot_table <- gtable_add_grob(plot_table, xlabel, name = "xlab", 
  l = panel_dim$l, r = panel_dim$r, t = -1, clip = "off") <---- here

ylab_width <- grobWidth(ylabel) + 
  if (is.null(labels$y)) unit(0, "lines") else unit(0.5, "lines")
plot_table <- gtable_add_cols(plot_table, ylab_width, pos = 0)
plot_table <- gtable_add_grob(plot_table, ylabel, name = "ylab",
  l = 1, b = panel_dim$b, t = panel_dim$t, clip = "off") <---- here

This allows one to use the hjust/vjust combined with plot.margin to move the axis.titles without clipping.

On request I filled this a bug on github .