Rstuido 无法将图片存为svg格式，并且Cairo包无法加载
library("Cairo")
Error: package or namespace load failed for ‘Cairo’:
.onLoad failed in loadNamespace() for 'Cairo', details:
  call: dyn.load(file, DLLpath = DLLpath, ...)
  error: unable to load shared object '/Library/Frameworks/R.framework/Versions/3.4/Resources/library/Cairo/libs/Cairo.so':
  dlopen(/Library/Frameworks/R.framework/Versions/3.4/Resources/library/Cairo/libs/Cairo.so, 6): Library not loaded: /opt/X11/lib/libfreetype.6.dylib
  Referenced from: /Library/Frameworks/R.framework/Versions/3.4/Resources/library/Cairo/libs/Cairo.so
  Reason: image not found