我怎样才能让ggplot2的图例和我的情节一样高？ [英] How can I make the legend in ggplot2 the same height as my plot?

问题描述

我使用 ggplot2 （版本0.9.3.1）在R（版本R版本3.0.1（2013-05-16））中生成了一个简单的图表，一组数据的相关系数。目前，绘图右侧的图例颜色条是整个绘图尺寸的一小部分。

我希望图例颜色条与图的高度相同。我认为我可以使用 legend.key.height 来做到这一点，但我发现事实并非如此。我调查了 grid package unit 函数，发现里面有一些标准化单元，但是当我尝试它们时（ unit（1，npc）），颜色条显得太高而离开页面。

如何让图例与图表本身的高度相同？

完整的自包含示例是下面：

$ $ p $ ＃加载所需的库
库（ggplot2）
库（网格）$ b $生成一个样本数据集合
variables = c（Var1，Var2，Var3）
$ data = matrix（runif（9，-1，1），3，3）
diag（data）= 1
colnames（data）=变量
rownames（data）=变量

＃生成绘图
corrs = data
ggplot（melt（corrs），aes（x = Var1，y = Var2，fill = value））+
geom_tile（）+
geom_text（parse = TRUE，aes（label = sprintf（％。2f，value）），size = 3，color =white）+
theme_bw（）+
主题（panel.border = element_blank（），
axis.text.x = element_text（angle = 90，vjust = 0.5，hjust = 1），
aspect.ratio = 1，
legend.position =right，
legend.key.height = unit（1，inch））+
labs（x =，y =，fill =，title =Correlation Coefficients）+
scale_fill_gradient2（limits = c（-1,1），expand = c（0,0），
low =静音（红色），
mid =黑色，
高=静音（蓝色））


解决方案

看起来相当棘手，最接近的是这个，

  ## panel height是1null，所以我们通过（1，npc） -  sum（ggplotGrob（plot）[[heights]）从1npc 
 ##和1line减去其他高度的默认绘图边距
 
 panel_height = unit ]  -   - 单位（1，line）
绘图+指南（fill = guide_colorbar（barheight = panel_height））
  

不幸的是，垂直理由是a关闭。

I have generated a simple plot in R (version R version 3.0.1 (2013-05-16)) using ggplot2 (version 0.9.3.1) that shows the correlation coefficients for a set of data. Currently, the legend colorbar on the right side of the plot is a fraction of the entire plot size.

I would like the legend colorbar to be same height as the plot. I thought that I could use the legend.key.height to do this, but I have found that is not the case. I investigated the grid package unit function and found that there were some normalized units in there but when I tried them (unit(1, "npc")), the colorbar was way too tall and went off the page.

How can I make the legend the same height as the plot itself?

A full self contained example is below:

# Load the needed libraries
library(ggplot2)
library(grid)
library(scales)
library(reshape2)

# Generate a collection of sample data
variables = c("Var1", "Var2", "Var3")
data = matrix(runif(9, -1, 1), 3, 3)
diag(data) = 1
colnames(data) = variables
rownames(data) = variables

# Generate the plot
corrs = data
ggplot(melt(corrs), aes(x = Var1, y = Var2, fill = value)) +
  geom_tile() +
  geom_text(parse = TRUE, aes(label = sprintf("%.2f", value)), size = 3, color = "white") +
  theme_bw() +
  theme(panel.border = element_blank(),
        axis.text.x = element_text(angle = 90, vjust = 0.5, hjust = 1),
        aspect.ratio = 1,
        legend.position = "right",
        legend.key.height = unit(1, "inch")) +
        labs(x = "", y = "", fill = "", title = "Correlation Coefficients") +
        scale_fill_gradient2(limits = c(-1, 1), expand = c(0, 0),
                             low = muted("red"),
                             mid = "black",
                             high = muted("blue"))

解决方案

It seems quite tricky, the closest I got was this,

## panel height is 1null, so we work it out by subtracting the other heights from 1npc
## and 1line for the default plot margins

panel_height = unit(1,"npc") - sum(ggplotGrob(plot)[["heights"]][-3]) - unit(1,"line")
plot + guides(fill= guide_colorbar(barheight=panel_height))

unfortunately the vertical justification is a bit off.

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