title: In grDevices::png(..., res = dpi, units = "in") : failed to load cairo DLL
body: <p>I have used ggsave to save png's a million times and I think this has to do with upgrading to R 3.5, not sure, but now I cannot do so anymore. Why has this stopped working?</p>
  
  <pre><code>library(ggplot2)
  qq = c(1,2)
  rr = c(1,2)
  dd = data.frame(x=qq,y=rr)
  pp = ggplot(dd, aes(x=x,y=y))+geom_line()
  ggsave(filename = "pp.png", plot = hists, path = plotPath, device = 
  "png", width = 6, height = 4, units = "in")
  </code></pre>
  
  <p>And I get</p>
  
  <blockquote>
    <p>Warning message:
    In grDevices::png(..., res = dpi, units = "in") : failed to load cairo DLL</p>
  </blockquote>
  
  <p>And the plot does not save.  What gives?  Yesterday I spent a long time repairing svg file saving but I was lucky enough to have the right library files on my computer in another place, which I could distinguish from the error messages, search and find on my computer, but here I got nothing.  I installed <code>cairo</code> via <code>brew install cairo</code> as suggested but did not help.  </p>