538-ify ggplot输出：在R网格图形中验证pictureGrob [英] 538-ify ggplot output: justifying pictureGrob in R grid graphics

问题描述

，但这似乎取决于一个 stringWidth 实用程序函数，它没有图片的合作伙伴（？）]

我已经提出了一个类似的问题，关于 gridextra表格，但作为baptiste的评论，'理由总是相当尴尬，以处理网格'。

任何帮助表示赞赏;可以重复使用的代码（注意 grImport c>需要ghostscript安装）：



  require（grImport）
 require（ggplot2）
 require gridExtra）
 
 #nb：你还需要在你的机器上安装ghostscript。 
＃我有一段时间让ghostscript正常工作。 
＃从R邮件列表的肠子里，我发现这个有用的提示
＃from Paul Murrell本人：
 #https：//www.mail-archive.com/r-help@ r-project.org/msg203180.html 
 $ b $＃#YMMV，这个工作在我的机器上：
 #gswin<  -  shortPathName（C：/ Program Files / gs / gs9.15 / bin / gswin64c.exe）
＃Sys.setenv（R_GSCMD = gswin）
 
 
＃有趣的小月亮
 PostScriptTrace（
 file = file.path（system.file（package =RGraphics），extra，comic_moon.ps），
 outfilename =comic_moon.xml）
 moon < -  readPicture（comic_moon 
 
 $ b annotate_me<  - 函数b 
 $ b #make a gTree 
 foo<  -  gTree（
 children = gList（
 rectGrob（gp = gpar（fill = bg_c​​olor）），
 pictureGrob （
 picture = some_picture，
x = 0，y = 0.5，
＃width =？
）
）
）
 
 final<  -  arrangeGrob（
 plo t_to_annotate，foo，
 nrow = 2，heights = c（19,1）
）
 
 return（final）
} 
 
 
 annotate_me（
 plot_to_annotate = qplot（mpg，data = mtcars），
 some_picture = moon 
）
  




解决方案

我相信widthDetails没有为pictureGrobs实现，所以说理由是随机的。



以下是一种方法：定义对象的宽度，并将其放置在x = 0.5宽度处。 $ b


  require（grImport）
 （Picture，
 paths = list（new（PictureFill，
x = c（0,1,0,1）），
y = c（0,0 ，1，1））），
 summary = new（PictureSummary，
 numPaths = 1，
 xscale = c（0，1），
图片Grob（沙漏，use.gc = FALSE，x =单位（1，行），
宽度=单位（2，line），gp = gpar（fill =red））
 library（ggplot2）
 library（gtable）
 library（dplyr）
 
p <-qplot（1,1）
g < -  ggplotGrob（p）
 
 grid.newpage（）
g％>％
 gtable_add_rows（unit（ 2，lines））％>％
 gtable_add_grob（rectGrob（gp = gpar（fill =gray）），name =border，
t = nrow（g）+ 1,1 = 1，r = ncol（g））％>％
 gtable_add_grob（g1，t = nrow（g）+1，l = 1，r = ncol（g））％>％
 gtable_add_grob（textGrob（text here，x = 1，hjust = 1，gp = gpar（col =white）），
 name =text，t = nrow（g）+ 1，l = 1，r = ncol（g））％>％
 grid.draw 
  




I am trying to write a little utility function that will annotate my plots Reuben Fischer-Baum style with a nice little logo and url at the bottom - eg:

I've figured out how to get a postscript file loaded into R; it's justifying the image on the bottom of the plot that's driving me crazy. I can't get the pictureGrob to left justify; at best I can get it to center on the left hand side of my plot, but half of my image gets cut off, like this reproducible example below:

Tinkering with the width setting can sort of approximate what I'm trying to accomplish by limiting the buffer around the pictureGrob, but what I really want, I think, is to left justify the picture itself inside of its viewport OR make the viewport completely snug to the picture. [Paul Murrell does something similar on p. 162 of the grid book, but that seems to depend on a stringWidth utility function that has no partner for pictures(?)]

I've asked a similar question about gridextra tables, but as baptiste comments there, 'Justification is always rather awkward to handle in grid'.

Any help is appreciated; a pointer to any conceptual discussion of what is happening with justification in grid would be spectacular.

Reproducible code (note that grImport requires a ghostscript install):

require(grImport)
require(ggplot2)
require(gridExtra)

#nb: you also need ghostscript installed on your machine.
#I had a hell of a time getting ghostscript to work properly.  
#From the bowels of a R mailing list, I found this helpful tip 
#from Paul Murrell himself:
#https://www.mail-archive.com/[e-mail]/msg203180.html

#YMMV, THIS WORKED ON MY MACHINE:
  #gswin <- shortPathName("C:/Program Files/gs/gs9.15/bin/gswin64c.exe")
  #Sys.setenv(R_GSCMD = gswin)


#get a fun little moon
PostScriptTrace(
  file=file.path(system.file(package = "RGraphics"), "extra", "comic_moon.ps"),
  outfilename="comic_moon.xml")
moon <- readPicture("comic_moon.xml")


annotate_me <- function(
  plot_to_annotate,
  some_picture,
  bg_color="gray30"
) {

  #make a gTree
  foo <- gTree(
    children=gList(
      rectGrob(gp=gpar(fill=bg_color)),
      pictureGrob(
        picture=some_picture,
        x=0, y=0.5,
        #width=?
      )
    )
  )

  final <- arrangeGrob(
    plot_to_annotate, foo,
    nrow=2, heights=c(19,1)
  )

  return(final)
}


annotate_me(
  plot_to_annotate=qplot(mpg, data=mtcars),
  some_picture=moon
)

解决方案

I believe widthDetails isn't implemented for pictureGrobs, so justification does random things.

Here's one approach: define the width of your object, and place it at x = 0.5 width.

require(grImport)
hourglass <- new("Picture",
                 paths= list(new("PictureFill",
                                 x=c(0, 1, 0, 1),
                                 y=c(0, 0, 1, 1))),
                 summary= new("PictureSummary",
                              numPaths=1,
                              xscale=c(0, 1),
                              yscale=c(0, 1)))

g1 <- pictureGrob(hourglass, use.gc=FALSE,x=unit(1,"line"),
                  width=unit(2,"line"), gp=gpar(fill="red"))
library(ggplot2)
library(gtable)
library(dplyr)

p <- qplot(1,1)
g <- ggplotGrob(p) 

grid.newpage()
g %>%
  gtable_add_rows(unit(2,"lines")) %>%
  gtable_add_grob(rectGrob(gp=gpar(fill="grey")), name="border",
                  t=nrow(g)+1,l=1,r=ncol(g)) %>%
  gtable_add_grob(g1, t=nrow(g)+1,l=1,r=ncol(g)) %>%
  gtable_add_grob(textGrob("text here", x=1, hjust=1, gp=gpar(col="white")),
                  name = "text", t=nrow(g)+1,l=1,r=ncol(g)) %>%
  grid.draw

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