fix scale_units when both unit and trans are specified, closes #357

NEWS.md

@@ -4,6 +4,8 @@
   `units_options(simplify = FALSE)` reverting a change from #310; #355
   @billdenney
 
+* Fix `scale_units` when both `unit` and `trans` are specified; #357
+
 # version 0.8-3
 
 * Remove tolerance from comparisons with logical operators, restoring behavior

R/scale_units.R

@@ -88,13 +88,6 @@ MakeScaleContinuousPositionUnits <- function() {
     ggplot2::ScaleContinuousPosition,
     units = NULL,
 
-    train = function(self, x) {
-      if (length(x) == 0) return()
-      if (!is.null(self$units))
-        units(x) <- as_units(1, self$units)
-      self$range$train(x)
-    },
-
     map = function(self, x, limits = self$get_limits()) {
       if (inherits(x, "units")) {
         if (is.null(self$units))
@@ -107,6 +100,9 @@ MakeScaleContinuousPositionUnits <- function() {
     },
 
     transform = function(self, x) {
+      if (!is.null(self$units))
+        units(x) <- as_units(1, self$units)
+
       new_x <- ggplot2::ggproto_parent(
         ggplot2::ScaleContinuousPosition, self)$transform(drop_units(x))
       as_units(new_x, units(x))

tests/testthat/test_plot.R

@@ -71,9 +71,11 @@ test_that("axis transformations do not affect displayed units", {
 
   p0 <- ggplot(df, aes(y=a, x=a)) + geom_point()
   p1 <- p0 + scale_x_units(trans='log10') + scale_y_units(trans='sqrt')
+  p2 <- p0 + scale_x_units(trans="log10", unit="mm")
 
   vdiffr::expect_doppelganger("ggplot2 default", p0)
   vdiffr::expect_doppelganger("ggplot2 transformed", p1)
+  vdiffr::expect_doppelganger("ggplot2 trans + unit", p2)
 })
 
 do.call(units_options, units:::.default_options)