Apply two transformations on one axis

Question

I have found coord_trans, but I\'d like to apply log10 and reverse to my x-axis. I tried applying two transformation

ggplo         


        

Answer 1

I wandered in here looking for a 'composition of scales' function. I think one might be able to write such a thing as follows:

# compose transforms a and b, applying b first, then a:
`%::%`  <- function(atrans,btrans) {
  mytran <- scales::trans_new(name      = paste(btrans$name,'then',atrans$name),
                              transform = function(x) { atrans$transform(btrans$transform(x)) },
                              inverse   = function(y) { btrans$inverse(atrans$inverse(y)) },
                              domain    = btrans$domain,  # this could use improvement...
                              breaks    = btrans$breaks,  # not clear how this should work, tbh
                              format    = btrans$format)

}

ph <- ggplot(mtcars, aes(wt, mpg)) +
  geom_point() +
  scale_y_continuous(trans=scales::reverse_trans() %::% scales::log10_trans())
print(ph)