如何在通过gridExtra中的range.grid创建的图表周围添加边框，其中包含一组ggplot2散点图 [英] How to add a border around a chart created via arrange.grid in gridExtra encompassing a set ggplot2 scatter plots

问题描述

我正在使用以下代码:

# Libs
require(ggplot2); require(gridExtra); require(grid)

# Generate separate charts
chrts_list_scts <- list()

# Data
data("mtcars")

# A
chrts_list_scts$a <- ggplot(mtcars) +
  geom_point(size = 2, aes(x = mpg, y = disp,
                           colour = as.factor(cyl))) +
  geom_smooth(aes(x = mpg, y = disp),
              method = "auto") +
  xlab("MPG") +
  ylab("Disp") +
  theme_bw() +
  theme(panel.grid.major = element_blank(),
        panel.grid.minor = element_blank(),
        legend.position = "none")

# B
chrts_list_scts$b <- ggplot(mtcars) +
  geom_point(size = 2, aes(x = mpg, y = drat,
                           colour = as.factor(cyl))) +
  geom_smooth(aes(x = mpg, y = drat),
              method = "auto") +
  xlab("MPG") +
  ylab("Drat") +
  theme_bw() +
  theme(panel.grid.major = element_blank(),
        panel.grid.minor = element_blank(),
        legend.position = "none")

# C
chrts_list_scts$c <- ggplot(mtcars) +
  geom_point(size = 2, aes(x = mpg, y = qsec,
                           colour = as.factor(cyl))) +
  geom_smooth(aes(x = mpg, y = qsec),
              method = "auto") +
  xlab("MPG") +
  ylab("QSEC") +
  guides(colour = guide_legend(title = "cyl")) +
  theme_bw() +
  theme(panel.grid.major = element_blank(),
        panel.grid.minor = element_blank(),
        legend.position = "bottom",
        legend.key = element_rect(colour = NA))

# Arrange grid
png(filename = "chrts.PNG", width = 6,
    height = 10, units = 'in', res = 300)
title_text <- c("mtcars")
chrts_list_scts$all_scts <- grid.arrange(chrts_list_scts$a,
                                         chrts_list_scts$b,
                                         chrts_list_scts$c,
                                         top =
                                           textGrob(label = title_text,
                                                    gp = gpar(
                                                      fontsize = 14,
                                                      font = 2)))
dev.off()
rm(title_text)

要生成以下图表:

我有兴趣在该图表周围添加边框，如下图所示:

我试图通过在代码中添加polygonGrob来解决此请求:

I tried to address this request via adding polygonGrob in the code:

chrts_list_scts$all_scts <- grid.arrange(chrts_list_scts$dep_work,
                                         chrts_list_scts$chld_work,
                                         chrts_list_scts$pens,
                                         polygonGrob(x = c(0,0.5,1.05),
                                                     y = c(0,0.5,1.05)
                                                     ),
                                         top =
                                           textGrob(label = title_text,
                                                    gp = gpar(
                                                      fontsize = 14,
                                                      font = 2)))

但是这会生成一个无意义的图表，底部有一条线.我看了看似相似的

but this generates a pointless chart with one line across in the bottom. I had a look at the seeming similar discussion on SO but it wasn't clear to me how to arrive at a working solution.

除了生成边界外，我还想:

In addition to generating the border, I would like to:

1. 能够对边框的美感进行一些控制，例如更改边框的大小和颜色.
2. 理想情况下，我想将此解决方案封装在arrange.grid调用内 中.因此，在对象chrts_list_scts$all_scts处具有所有元素，包括图表和围绕它们的整洁边框.

1. Be able to exercise some control over the border aesthetics, like changing size and colour of the border.
2. Ideally, I would like to encapsulate this solution within the arrange.grid call. So at the object chrts_list_scts$all_scts has all elements including charts and neat border around all of them.

---

我很乐意接受仅解决边界方面主要要求的解决方案，如果有建议的解决方案与其余两点相匹配，那就更好了.

推荐答案

1)使用问题示例提供的链接中的鸢尾花示例(但经过进一步简化)，只需添加最后一行即可.修改gpar(...)组件(可能还有width和height)以获得不同的美感. (这没有封装在grid.arrange调用中.)

1) Using the iris example (but further simplified) from the link provided in the question just add the last line. Modify the gpar(...) components (and possibly the width and height) to get different aesthetics. (This is not encapsulated in the grid.arrange call.)

library(ggplot2)
library(grid)
library(gridExtra)

g <- ggplot(iris, aes(Sepal.Width, Sepal.Length)) + geom_point()
grid.arrange(g, g, ncol=2)


# next line adds border
grid.rect(width = .98, height = .98, gp = gpar(lwd = 2, col = "blue", fill = NA))

(情节后继续)

2):这是解决方案(1)的一种变体，其中在正面，通过创建grob来分别保存gt gTree中的图形和边框.另一方面，它确实涉及一些额外的复杂性:

2) This is a variation of solution (1) in which on the plus side encapsulates both the graphics and border in the gt gTree by creating grobs to hold each. On the other hand it does involve some additional complexity:

grid.newpage()
ga <- arrangeGrob(g, g, ncol = 2)
gb <- rectGrob(height = .98, width = .98, gp = gpar(lwd = 2, col = "blue", fill = NA)) # border, no fill
gt <- gTree(children = gList(ga, gb))
grid.draw(gt)

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