ggplot2 PDF 输出中的 Unicode 字符 [英] Unicode Characters in ggplot2 PDF Output

问题描述

如何在使用 ggplot2 创建的 PDF 图中使用 Unicode 字符作为标签、标题和类似内容?

考虑以下示例:

库(ggplot2)qplot(Sepal.Length, Petal.Length, data=iris, main="Aʙᴄᴅᴇғɢʜɪᴊᴋʟᴍɴᴏᴘǫʀsᴛᴜᴠᴡxʏᴢ")ggsave("t.pdf")

情节的标题使用 Unicode 字符(小写字母)，在输出中显示为 ....该问题仅出现在 pdf 图中；如果我用 ggsave("t.png") 替换最后一行，则输出符合预期.

我做错了什么?我拥有的 R 脚本采用 UTF-8 编码.一些系统信息:

R 版本 2.14.1 (2011-12-22)平台:x86_64-pc-linux-gnu(64 位)语言环境:[1] LC_CTYPE=en_US.UTF-8 LC_NUMERIC=C[3] LC_TIME=en_US.UTF-8 LC_COLLATE=en_US.UTF-8[5] LC_MONETARY=en_US.UTF-8 LC_MESSAGES=en_US.UTF-8[7] LC_PAPER=C LC_NAME=C[9] LC_ADDRESS=C LC_TELEPHONE=C[11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C附带的基础包:[1] stats graphics grDevices utils datasets 方法基础

在寻找这个问题的解决方案时，我发现了一些;虽然它看起来与标题没有直接关系，但里面有很多关于让字体在 R 中做你想做的事情.

EDIT 每个评论中的请求，这里是特定于 Windows 的代码:

库(ggplot2)windowsFonts(myCustomWindowsFontName=windowsFont("DejaVu Sans"))cairo_pdf("example.pdf", family="myCustomWindowsFontName")qplot(Sepal.Length, Petal.Length, data=iris, main="Aʙᴄᴅᴇғɢʜɪᴊᴋʟᴍɴᴏᴘǫʀsᴛᴜᴠᴡxʏᴢ")dev.off()

要使用基本图形命令 cairo_pdf()，只需首先使用 windowsFonts() 命令定义您的字体系列就足够了，如上所示.当然，请确保您使用的是系统上实际拥有的字体，并且该字体实际上具有您需要的所有字形.

以下注释中有关 DLL 文件的说明是我在 library(Cairo) 中获取 Cairo() 和 CairoPDF() 命令所需的) 在 Windows 上工作.然后:

库(ggplot2)图书馆(开罗)windowsFonts(myCustomWindowsFontName=windowsFont("DejaVu Sans"))CairoPDF("example.pdf")par(family="myCustomWindowsFontName")qplot(Sepal.Length, Petal.Length, data=iris, main="Aʙᴄᴅᴇғɢʜɪᴊᴋʟᴍɴᴏᴘǫʀsᴛᴜᴠᴡxʏᴢ")dev.off()

How can I use Unicode characters for labels, titles and similar things in a PDF plot created with ggplot2?

Consider the following example:

library(ggplot2)
qplot(Sepal.Length, Petal.Length, data=iris, main="Aʙᴄᴅᴇғɢʜɪᴊᴋʟᴍɴᴏᴘǫʀsᴛᴜᴠᴡxʏᴢ")
ggsave("t.pdf")

The title of the plot uses Unicode characters (small caps), which in the output appear as .... The problem occurs only with pdf plots; if I replace the last line with ggsave("t.png"), then the output is as expected.

What am I doing wrong? The R script I have is in UTF-8 encoding. Some system information:

R version 2.14.1 (2011-12-22)
Platform: x86_64-pc-linux-gnu (64-bit)

locale:
 [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C              
 [3] LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8    
 [5] LC_MONETARY=en_US.UTF-8    LC_MESSAGES=en_US.UTF-8   
 [7] LC_PAPER=C                 LC_NAME=C                 
 [9] LC_ADDRESS=C               LC_TELEPHONE=C            
[11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C       

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base

When searching for a solution for this problem, I found some evidence that R uses a single-byte encoding for mutli-byte encodigns such as UTF-8 for PDF or postscript output. I also found suggestions to, for instance, be able to get the Euro sign working, but no general solution.

解决方案

As Ben suggested, cairo_pdf() is your friend. It also allows you to embed non-postscript fonts (i.e. TTF/OTF) in the PDF via the family argument (crucial if you don't happen to have any postscript fonts that contain the glyphs you want to use). For example:

library(ggplot2)
cairo_pdf("example.pdf", family="DejaVu Sans")
qplot(Sepal.Length, Petal.Length, data=iris, main="Aʙᴄᴅᴇғɢʜɪᴊᴋʟᴍɴᴏᴘǫʀsᴛᴜᴠᴡxʏᴢ")
dev.off()

...gives a PDF that looks like this:

See also this question; though it doesn't look directly relevant from the title, there is a lot in there about getting fonts to do what you want in R.

EDIT per request in comments, here is the windows-specific code:

library(ggplot2)
windowsFonts(myCustomWindowsFontName=windowsFont("DejaVu Sans"))
cairo_pdf("example.pdf", family="myCustomWindowsFontName")
qplot(Sepal.Length, Petal.Length, data=iris, main="Aʙᴄᴅᴇғɢʜɪᴊᴋʟᴍɴᴏᴘǫʀsᴛᴜᴠᴡxʏᴢ")
dev.off()

To use the base graphics command cairo_pdf() it should suffice to just define your font family with the windowsFonts() command first, as shown above. Of course, make sure you use a font that you actually have on your system, and that actually has all the glyphs that you need.

TThe instructions about DLL files in the comments below are what I had to do to get the Cairo() and CairoPDF() commands in library(Cairo) to work on Windows. Then:

library(ggplot2)
library(Cairo)
windowsFonts(myCustomWindowsFontName=windowsFont("DejaVu Sans"))
CairoPDF("example.pdf")
par(family="myCustomWindowsFontName")
qplot(Sepal.Length, Petal.Length, data=iris, main="Aʙᴄᴅᴇғɢʜɪᴊᴋʟᴍɴᴏᴘǫʀsᴛᴜᴠᴡxʏᴢ")
dev.off()

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