Merge pull request #1077 from krlmlr/943-single-color-continuous-scale

Create correct legend for continuous color even if there is only one color

Author: hadley

NEWS

@@ -1,3 +1,6 @@
+* Create correct legend for continuous color even if there is only one color
+  (@krlmlr, #943)
+
 ggplot2 1.0.1.9000
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R/guide-colorbar.r

@@ -189,7 +189,11 @@ guide_train.colorbar <- function(guide, scale) {
   names(guide$key) <- c(output, ".label", ".value")
 
   # bar specification (number of divs etc)
-  .bar <- discard(pretty(scale_limits(scale), n = guide$nbin), scale_limits(scale))
+  .limits <- scale_limits(scale)
+  .bar <- discard(pretty(.limits, n = guide$nbin), scale_limits(scale))
+  if (length(.bar) == 0) {
+    .bar = unique(.limits)
+  }
   guide$bar <- data.frame(colour=scale_map(scale, .bar), value=.bar, stringsAsFactors = FALSE)
   if (guide$reverse) {
     guide$key <- guide$key[nrow(guide$key):1, ]