Merge pull request #1209 from krlmlr/871-transformed-breaks

Fix automatically computed breaks for "probit" scale

Author: hadley

NEWS

@@ -243,6 +243,9 @@ ggplot2 1.0.1.9xxx
   aesthetics (e.g. `aes(sapply(..density.., function(x) mean(x))))`
   (#1154, @NikNakk)
 
+* Automatically computed breaks do not lead to an error for transformations like
+  "probit" where the inverse can map to infinity (#871, @krlmlr)
+
 ggplot2 1.0.1
 ----------------------------------------------------------------
 

R/scale-.r

@@ -383,7 +383,8 @@ scale_breaks.continuous <- function(scale, limits = scale_limits(scale)) {
   # @kohske
   # TODO: replace NA with something else for flag.
   #       guides cannot discriminate oob from missing value.
-  breaks <- censor(scale$trans$transform(breaks), scale$trans$transform(limits))
+  breaks <- censor(scale$trans$transform(breaks), scale$trans$transform(limits),
+                   only.finite = FALSE)
   if (length(breaks) == 0) {
     stop("Zero breaks in scale for ", paste(scale$aesthetics, collapse = "/"),
       call. = FALSE)

tests/testthat/test-scales-breaks-labels.r

@@ -7,7 +7,6 @@ test_that("labels match breaks, even when outside limits", {
   expect_equal(scale_labels(sc), 1:4)
   expect_equal(scale_breaks_minor(sc), c(1, 1.5, 2, 2.5, 3))
 })
-.
 
 test_that("labels must match breaks", {
   expect_that(scale_x_discrete(breaks = 1:3, labels = 1:2),
@@ -236,3 +235,10 @@ test_that("breaks can be specified by names of labels", {
   expect_equal(as.vector(scale_labels(s)), LETTERS[1:3])
 
 })
+
+test_that("only finite or NA values for breaks for transformed scales (#871)", {
+  sc <- scale_y_continuous(limits = c(0.01, 0.99), trans = "probit",
+                           breaks = seq(0, 1, 0.2))
+  breaks <- scale_breaks(sc)
+  expect_true(all(is.finite(breaks) | is.na(breaks)))
+})