Error(s) in re-building vignettes:
--- re-building ‘classes.Rmd’ using rmarkdown
Quitting from lines 32-39 (classes.Rmd) 
Error: processing vignette 'classes.Rmd' failed with diagnostics:
R: NegativeOrZeroImageSize `' @ error/image.c/CloneImage/794
--- failed re-building ‘classes.Rmd’

--- re-building ‘engine.Rmd’ using rmarkdown
Warning: LaTeX Warning: Font shape declaration has incorrect series value `mc'.
Warning:                It should not contain an `m'! Please correct it.
Warning:                Found on input line 21.
Warning: LaTeX Warning: Font shape declaration has incorrect series value `mc'.
Warning:                It should not contain an `m'! Please correct it.
Warning:                Found on input line 24.
Warning: LaTeX Warning: Font shape declaration has incorrect series value `mc'.
Warning:                It should not contain an `m'! Please correct it.
Warning:                Found on input line 27.
Warning: LaTeX Warning: Font shape declaration has incorrect series value `mc'.
Warning:                It should not contain an `m'! Please correct it.
Warning:                Found on input line 47.
Warning in magick::image_write(imgOut, thispath, flatten = TRUE) :
  Writing image with 0 frames
Quitting from lines 61-62 (engine.Rmd) 
Error: processing vignette 'engine.Rmd' failed with diagnostics:
R: NegativeOrZeroImageSize `' @ error/image.c/CloneImage/794
--- failed re-building ‘engine.Rmd’

--- re-building ‘kable.Rmd’ using rmarkdown
Quitting from lines 53-57 (kable.Rmd) 
Error: processing vignette 'kable.Rmd' failed with diagnostics:
R: NegativeOrZeroImageSize `' @ error/image.c/CloneImage/794
--- failed re-building ‘kable.Rmd’

--- re-building ‘rmarkdown.Rmd’ using rmarkdown
Quitting from lines 34-38 (rmarkdown.Rmd) 
Error: processing vignette 'rmarkdown.Rmd' failed with diagnostics:
R: NegativeOrZeroImageSize `' @ error/image.c/CloneImage/794
--- failed re-building ‘rmarkdown.Rmd’

--- re-building ‘tests_and_coverage.Rmd’ using rmarkdown
--- finished re-building ‘tests_and_coverage.Rmd’

--- re-building ‘tex_packages.Rmd’ using rmarkdown
--- finished re-building ‘tex_packages.Rmd’

--- re-building ‘tikz.Rmd’ using rmarkdown
Quitting from lines 50-51 (tikz.Rmd) 
Error: processing vignette 'tikz.Rmd' failed with diagnostics:
R: NegativeOrZeroImageSize `' @ error/image.c/CloneImage/794
--- failed re-building ‘tikz.Rmd’

SUMMARY: processing the following files failed:
  ‘classes.Rmd’ ‘engine.Rmd’ ‘kable.Rmd’ ‘rmarkdown.Rmd’ ‘tikz.Rmd’

Error: Vignette re-building failed.
Execution halted