如何修复 R 中的“无法加载 cairo DLL”？

Question

I am running into this warning message that will stop execution.

Saving 8.04 x 5.67 in image
Warning messages:
1: In dev(file = filename, width = dim[1], height = dim[2], ...) :
  unable to load shared object '/usr/local/Cellar/r/3.5.0_1/lib/R/library/grDevices/libs//cairo.so':

  dlopen(/usr/local/Cellar/r/3.5.0_1/lib/R/library/grDevices/libs//cairo.so, 6): image not found
2: In dev(file = filename, width = dim[1], height = dim[2], ...) :
  failed to load cairo DLL

---

This is the code that generates that warning for me

library(tidyverse)
library(cowplot)

d <- sample_n(diamonds, 50)
g <- ggplot(d, aes(carat, price)) + geom_point()
gg <- list(g,g,g)

plot_grid(plotlist = gg, nrow=1) %>% 
  cowplot::ggsave(filename = paste0("~/Desktop/", paste0("testing", ".svg")), device = cairo_ps)

How do I go about fixing this error?

Ps I am a novice.

EDIT: This is my session information. I am not sure if this would be helpful. I have included it just in case.

sessionInfo()

R version 3.5.0 (2018-04-23)
Platform: x86_64-apple-darwin17.6.0 (64-bit)
Running under: macOS High Sierra 10.13.5

Matrix products: default
BLAS: /System/Library/Frameworks/Accelerate.framework/Versions/A/Frameworks/vecLib.framework/Versions/A/libBLAS.dylib
LAPACK: /System/Library/Frameworks/Accelerate.framework/Versions/A/Frameworks/vecLib.framework/Versions/A/libLAPACK.dylib

locale:
[1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8

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

other attached packages:
 [1] cowplot_0.9.2     forcats_0.3.0     stringr_1.3.1     dplyr_0.7.5      
 [5] purrr_0.2.5       readr_1.1.1       tidyr_0.8.1       tibble_1.4.2     
 [9] ggplot2_2.2.1     tidyverse_1.2.1   doParallel_1.0.11 iterators_1.0.9  
[13] foreach_1.4.4     lmerTest_3.0-1    lme4_1.1-17       Matrix_1.2-14    

loaded via a namespace (and not attached):
 [1] tidyselect_0.2.4  reshape2_1.4.3    splines_3.5.0     haven_1.1.1      
 [5] lattice_0.20-35   argparse_1.1.1    colorspace_1.3-2  getopt_1.20.2    
 [9] yaml_2.1.19       rlang_0.2.1       nloptr_1.0.4      pillar_1.2.3     
[13] foreign_0.8-70    glue_1.2.0        readxl_1.1.0      modelr_0.1.2     
[17] bindrcpp_0.2.2    bindr_0.1.1       plyr_1.8.4        cellranger_1.1.0 
[21] munsell_0.4.3     findpython_1.0.3  gtable_0.2.0      rvest_0.3.2      
[25] codetools_0.2-15  psych_1.8.4       labeling_0.3      broom_0.4.4      
[29] proto_1.0.0       Rcpp_0.12.17      scales_0.5.0      jsonlite_1.5     
[33] mnormt_1.5-5      hms_0.4.2         stringi_1.2.2     numDeriv_2016.8-1
[37] grid_3.5.0        cli_1.0.0         tools_3.5.0       magrittr_1.5     
[41] lazyeval_0.2.1    crayon_1.3.4      pkgconfig_2.0.1   MASS_7.3-49      
[45] xml2_1.2.0        lubridate_1.7.4   rstudioapi_0.7    assertthat_0.2.0 
[49] minqa_1.2.4       httr_1.3.1        R6_2.2.2          nlme_3.1-137     
[53] compiler_3.5.0   

Answer 1

The Homebrew version of R no longer supports cairo ( more info here ), so graphical devices like svg() , cairo_pdf() , and cairo_ps() in base R won't work if you install R via brew install r . You have to use other graphical devices (eg, png , jpeg , pdf ). If you need SVG output, ggsave() requires the svglite package and uses svglite::svglite() to save your plot to an SVG file.

If you do want to use Homebrew to install R, I recommend brew cask install r .

Answer 2

I only have a Windows machine to offer, but the following worked for both saving a .svg and .eps of your cowplot (after installing the package svglite ):

# install.packages(svglite)
library(tidyverse)
library(cowplot)

d <- sample_n(diamonds, 50)
g <- ggplot(d, aes(carat, price)) + geom_point()
gg <- list(g,g,g)

plot_grid(plotlist = gg, nrow=1)
ggsave(filename = "testing.svg")
ggsave(filename = "testing.eps")

You can of course modify the filename to something like "~/Desktop/testing.svg" , depending on where you want to safe your plot. Note that ggsave per default saves the last active plot, and the ending of the filename you specify should automatically trigger the right device.