geom_bar()+象形图,怎么样？

Question

(见帖子底部的更新)

最初的帖子,2014-07-29 11:43:38Z

我在"经济学人"的网站上看到了这些图片,并想知道是否有可能制作出一个geom_bar()嵌入这种说明性图标的图片？(下面的虚拟数据)

虚拟数据,

require(ggplot2)

# Generate data
df3 <- data.frame(units = c(1.3, 1.8, 2.7, 4.2, 4.7, 6.7, 20), 
                   what = c('Wikipedia', 'London Olympic Park', 'Aircraft carrier', 
                            'The Great Pyramid', 'Stonehenge', 'Burj Khalifas', 
                            'Empire State Building'))

# make gs an ordered factor
df3$what <- factor(df3$what, levels = df3$what, ordered = TRUE)

    #plots
    ggplot(df3, aes(what, units)) + geom_bar(fill="white", colour="darkgreen", 
           alpha=0.5, stat="identity") + coord_flip() + scale_x_discrete() + 
           scale_y_continuous(breaks=seq(0, 20, 2)) + theme_bw() + 
           theme(axis.title.x  = element_blank(), axis.title.y  = element_blank())

更新#1,2014-07-29 15:07:51Z

显然罗伯特格兰特已经开始构建一个R函数来生成带有象形图的条形图,它可以在Github上找到.感谢Andrie提供的信息.我正在努力研究罗伯特的功能是否能够满足我的需求.

如果您对如何使用Robert的功能回答我的问题有任何建议,请发信息.

更新#2,2014-08-02 12:35:19Z

以下是Grant的R-pictogram-function如何工作的简单说明

# in case you don't alredy have RCurl
# install.packages("RCurl", dependencies = TRUE)
source_github <- function(u) {
  # load package
  require(RCurl)

  # read script lines from website and evaluate
  script <- getURL(u, ssl.verifypeer = FALSE)
  eval(parse(text = script),envir=.GlobalEnv)
}

得到这个脚本形成这个SO答案

source_github("https://raw.githubusercontent.com/robertgrant/pictogram/master/pictogram.R")

# install.packages("png", dependencies = TRUE)
  require(png)

img <- readPNG(system.file("img", "Rlogo.png", package="png"))
pictogram(icon = img, n = c( 12, 35, 7),
grouplabels=c("12 R logos","35 R logos","7 R logos"))

这给你这种情节

Answer 1

以下是我根据这个想法提出的建议.R徽标取自维基百科.

library(png)
fill_images <- function()
{
  l <- list()
  for (i in 1:nrow(df3)) 
  {
    for (j in 1:floor(df3$units[i]))
    {
      #seems redundant, but does not work if moved outside of the loop (why?)
      img <- readPNG("~/../Rlogo.png")
      g <- rasterGrob(img, interpolate=TRUE)
      l <- c(l, annotation_custom(g, xmin = i-1/2, xmax = i+1/2, ymin = j-1, ymax = j))
    }
  }
  l
}

p <- ggplot(df3, aes(what, units)) + 
  geom_bar(fill="white", colour="darkgreen", alpha=0.5, stat="identity") + 
  coord_flip() + 
  scale_y_continuous(breaks=seq(0, 20, 2)) + 
  scale_x_discrete() + 
  theme_bw() + 
  theme(axis.title.x  = element_blank(), axis.title.y  = element_blank()) + 
  fill_images()
p

我不太确定绘制局部图像的最佳方法是什么.

更新:

实际上,这比我预期的要容易.我通过在其中的一部分上绘制白色矩形来剪切图像.请注意,geom_bar应该在顶部,以便剪切矩形不会影响它.网格线有一个小问题(它们被这些白色矩形部分隐藏),所以我不得不硬编码这些的位置并手动恢复它们.当然,这不是一个理想的解决方案,但我不知道如何以编程方式检索网格位置.无论如何,最后的情节完成了工作,看起来也很奇特!

library(png)
fill_images <- function()
{
  l <- list()
  for (i in 1:nrow(df3)) 
  {
    for (j in 1:ceiling(df3$units[i]))
    {
      img <- readPNG("~/../Rlogo.png")
      g <- rasterGrob(img, interpolate=TRUE)
      l <- c(l, annotation_custom(g, xmin = i-1/2, xmax = i+1/2, ymin = j-1, ymax = j))
    }
  }
  l
}

clip_images <- function(restore_grid = TRUE)
{
  l <- list()
  for (i in 1:nrow(df3)) 
  {
    l <- c(l, geom_rect(xmin = i-1/2, xmax = i+1/2, 
                        ymin = df3$units[i], ymax = ceiling(df3$units[i]),
                        colour = "white", fill = "white"))
    if (restore_grid && ceiling(df3$units[i]) %in% major_grid) 
      l <- c(l, geom_segment(x = i-1, xend = i+1,
                             y = ceiling(df3$units[i]), 
                             yend = ceiling(df3$units[i]),
                             colour = grid_col, size = grid_size))
  }
  l
}

grid_col <- "grey50"
grid_size <- 0.6
major_grid <- 0:10 * 2
p <- ggplot(df3, aes(what, units)) + 
  fill_images() + 
  clip_images() +
  geom_bar(fill=NA, colour="darkgreen", size=1.2, alpha=0.5, stat="identity") + 
  coord_flip() + 
  scale_y_continuous(breaks=seq(0, 20, 2)) + 
  scale_x_discrete() + 
  theme_bw() + 
  theme(axis.title.x  = element_blank(), axis.title.y  = element_blank(),
        panel.grid.major.x = element_line(colour = grid_col, size = grid_size), 
        panel.grid.major.y = element_line(colour = NA)) 
p

要保存.svg文件,请使用eg

ggsave(file="test.svg", plot=p, width=10, height=8)

如果要将填充图像作为.svg文件,请查看grImport 包.您似乎必须手动将.svg转换为.ps(例如使用imagemagick),然后按照指南操作.

Answer 2

gridSVG支持R引擎无法使用的svg功能,例如填充模式和任意剪辑.这个例子很容易适应ggplot2,

library(grid)
library(gridSVG)
require(ggplot2)

p <- ggplot(df3, aes(what, units)) + 
  geom_bar(colour="black", stat="identity") +
  coord_flip()

pattern <- pattern(circleGrob(r=.4, gp=gpar(fill="grey")),
                   width=.05, height=.05)
registerPatternFill("circles", pattern)
gridsvg("pattern.svg")
print(p)
grid.force()
grid.patternFill("geom_rect.rect", grep=TRUE, group=FALSE,
                 label=rep("circles", length(levels(df3$what))))
dev.off()