Inverse of log2 transform through ggplot + coord_trans

Question

I would like to do inverse of log2 transform on my coordinates only.

From what I understand, exp_trans() and log_trans() go together, so

gg.plot +
  coord_trans(x="exp")

would perform inverse of log on the coordinates.

However, I noticed there is nothing like 2_trans() for log2_trans().

What are my options?

Answer 1

One option is to use scales::exp_trans(base =...) as a function instead of by name. Demonstrated for the y-axis below. The default break calculations are not that pretty with coord_trans() . Note that there are warnings about infinite values, but these are likely the expanded axis limits that go below the [0, Inf] domain for log-transforms.

library(ggplot2)

ggplot(pressure, aes(temperature, pressure)) +
  geom_line() +
  scale_y_log10() +
  coord_trans(y = scales::exp_trans(10))
#> Warning in trans$inverse(continuous_range_coord): NaNs produced
#> Warning in self$trans$y$inverse(panel_params$y.range): NaNs produced

^{Created on 2021-01-11 by the reprex package (v0.3.0)}