Devtools::check() errors with ggplot2 and gganimate

Package development
3

I have done some digging and I believe the primary cause of my problem is the animation package. It wants to use magick. It cannot find it so the function searches for ImageMagic. It cannot find it either because ImageMagicis not available for R version 3.4.2. Incidentally, I used HomeBrew to install it on computer, therefore it would have solved problem if it was not incompatable with R. Yihue Xie, the author of animation is aware of the problem and promises to update the package with`magick.'

I made some changes my code since publishing my post. Regardless, devtools::check() gives a new error:

Error in ggplot(df, xlim = xlim, ylim = ylim, col = gray(0.5)) : 
  could not find function "ggplot"
Calls: cfanim
Execution halted

Even with this error and other warnings and notes, my script successfully produces an animation. R Markdown produces an animation with several comments that seem to be unrelated to the devtools::check() output.