pdf_orientation() tells whether a pdf is in portrait
or landscape mode.
Examples
f1 <- pdf_create_blank(width = 8.5, height = 11)
pdf_orientation(f1)
#> [1] "portrait"
f2 <- pdf_create_blank(width = 11, height = 8.5, length = 2L)
pdf_orientation(f2)
#> [1] "landscape" "landscape"
unlink(f1)
unlink(f2)