Add access to direction argument of scales::brewer_pal

+ minor example and documentation fixes

Author: jiho

DESCRIPTION

@@ -25,7 +25,7 @@ Imports:
     grid,
     gtable (>= 0.1.1),
     reshape2,
-    scales (>= 0.2.3),
+    scales (>= 0.2.5),
     proto,
     MASS
 Suggests:

NEWS

@@ -1,3 +1,7 @@
+* Add access to the new `direction` argument of `scales::brewer_pal` and
+  simplify changing the order of colours for `scale_*_brewer` and
+  `scale_*_distiller` (@jiho, #1139)
+
 ggplot2 1.0.1.9000
 ----------------------------------------------------------------
 
@@ -99,8 +103,8 @@ ggplot2 1.0.1
 
 * Fixes to pass `R CMD check --run-donttest` in R-devel.
 
-* Improvements in to order of colours and legend display of continuous colour
-  scales extracted from colorbrewer palettes in `scale_*_distiller()` (@jiho, 1076)
+* Improvements to order of colours and legend display for continuous colour
+  scales extracted from colorbrewer palettes by `scale_*_distiller()` (@jiho, 1076)
 
 ggplot2 1.0.0
 ----------------------------------------------------------------

R/scale-brewer.r

@@ -32,14 +32,18 @@
 #' d + scale_colour_brewer(type = "seq")
 #' d + scale_colour_brewer(type = "seq", palette = 3)
 #'
-#' d + scale_colour_brewer(palette = "Blues")
+#' d + scale_colour_brewer(palette = "Greens")
 #' d + scale_colour_brewer(palette = "Set1")
 #'
 #' # scale_fill_brewer works just the same as
 #' # scale_colour_brewer but for fill colours
-#' ggplot(diamonds, aes(x = price, fill = cut)) +
-#'   geom_histogram(position = "dodge", binwidth = 1000) +
-#'   scale_fill_brewer()
+#' p <- ggplot(diamonds, aes(x = price, fill = cut)) +
+#'   geom_histogram(position = "dodge", binwidth = 1000)
+#' p + scale_fill_brewer()
+#' # the order of colour can be reversed
+#' p + scale_fill_brewer(direction = -1)
+#' # the brewer scales look better on a darker background
+#' p + scale_fill_brewer(direction = -1) + theme_dark()
 #'
 #' # Generate map data
 #' library(reshape2) # for melt
@@ -54,41 +58,40 @@
 #' v + scale_fill_distiller(palette = 2)
 #' v + scale_fill_distiller(type = "div")
 #' v + scale_fill_distiller(palette = "Spectral")
-#' v + scale_fill_distiller(palette = "Spectral", trans = "reverse")
 #' v + scale_fill_distiller(type = "qual")
 #' # Not appropriate for continuous data, issues a warning
-scale_colour_brewer <- function(..., type = "seq", palette = 1) {
-  discrete_scale("colour", "brewer", brewer_pal(type, palette), ...)
+scale_colour_brewer <- function(..., type = "seq", palette = 1, direction = 1) {
+  discrete_scale("colour", "brewer", brewer_pal(type, palette, direction), ...)
 }
 
 #' @export
 #' @rdname scale_brewer
-scale_fill_brewer <- function(..., type = "seq", palette = 1) {
-  discrete_scale("fill", "brewer", brewer_pal(type, palette), ...)
+scale_fill_brewer <- function(..., type = "seq", palette = 1, direction = 1) {
+  discrete_scale("fill", "brewer", brewer_pal(type, palette, direction), ...)
 }
 
 #' @export
 #' @rdname scale_brewer
-scale_colour_distiller <- function(..., type = "seq", palette = 1, values = NULL, space = "Lab", na.value = "grey50", guide = "colourbar") {
+scale_colour_distiller <- function(..., type = "seq", palette = 1, direction = -1, values = NULL, space = "Lab", na.value = "grey50", guide = "colourbar") {
   # warn about using a qualitative brewer palette to generate the gradient
   type <- match.arg(type, c("seq", "div", "qual"))
   if (type == "qual") {
     warning("Using a discrete colour palette in a continuous scale.\n  Consider using type = \"seq\" or type = \"div\" instead", call. = FALSE)
   }
   continuous_scale("colour", "distiller",
-    gradient_n_pal(rev(brewer_pal(type, palette)(6)), values, space), na.value = na.value, guide = guide, ...)
+    gradient_n_pal(brewer_pal(type, palette, direction)(6), values, space), na.value = na.value, guide = guide, ...)
   # NB: 6 colours per palette gives nice gradients; more results in more saturated colours which do not look as good
 }
 
 #' @export
 #' @rdname scale_brewer
-scale_fill_distiller <- function(..., type = "seq", palette = 1, values = NULL, space = "Lab", na.value = "grey50", guide = "colourbar") {
+scale_fill_distiller <- function(..., type = "seq", palette = 1, direction = -1, values = NULL, space = "Lab", na.value = "grey50", guide = "colourbar") {
   type <- match.arg(type, c("seq", "div", "qual"))
   if (type == "qual") {
     warning("Using a discrete colour palette in a continuous scale.\n  Consider using type = \"seq\" or type = \"div\" instead", call. = FALSE)
   }
   continuous_scale("fill", "distiller",
-    gradient_n_pal(rev(brewer_pal(type, palette)(6)), values, space), na.value = na.value, guide = guide, ...)
+    gradient_n_pal(brewer_pal(type, palette, direction)(6), values, space), na.value = na.value, guide = guide, ...)
 }
 
 # icon.brewer <- function() {

man/scale_brewer.Rd

@@ -9,20 +9,23 @@
 \alias{scale_fill_distiller}
 \title{Sequential, diverging and qualitative colour scales from colorbrewer.org}
 \usage{
-scale_colour_brewer(..., type = "seq", palette = 1)
+scale_colour_brewer(..., type = "seq", palette = 1, direction = 1)
 
-scale_fill_brewer(..., type = "seq", palette = 1)
+scale_fill_brewer(..., type = "seq", palette = 1, direction = 1)
 
-scale_colour_distiller(..., type = "seq", palette = 1, values = NULL,
-  space = "Lab", na.value = "grey50", guide = "colourbar")
+scale_colour_distiller(..., type = "seq", palette = 1, direction = -1,
+  values = NULL, space = "Lab", na.value = "grey50",
+  guide = "colourbar")
 
-scale_fill_distiller(..., type = "seq", palette = 1, values = NULL,
-  space = "Lab", na.value = "grey50", guide = "colourbar")
+scale_fill_distiller(..., type = "seq", palette = 1, direction = -1,
+  values = NULL, space = "Lab", na.value = "grey50",
+  guide = "colourbar")
 
-scale_color_brewer(..., type = "seq", palette = 1)
+scale_color_brewer(..., type = "seq", palette = 1, direction = 1)
 
-scale_color_distiller(..., type = "seq", palette = 1, values = NULL,
-  space = "Lab", na.value = "grey50", guide = "colourbar")
+scale_color_distiller(..., type = "seq", palette = 1, direction = -1,
+  values = NULL, space = "Lab", na.value = "grey50",
+  guide = "colourbar")
 }
 \arguments{
 \item{...}{Other arguments passed on to \code{\link{discrete_scale}}
@@ -33,6 +36,10 @@ to control name, limits, breaks, labels and so forth.}
 \item{palette}{If a string, will use that named palette.  If a number, will
 index into the list of palettes of appropriate \code{type}}
 
+\item{direction}{Sets the order of colors in the scale. If 1, the default,
+colors are as output by \code{\link[RColorBrewer]{brewer.pal}}. If -1, the
+order of colors is reversed.}
+
 \item{values}{if colours should not be evenly positioned along the gradient
 this vector gives the position (between 0 and 1) for each colour in the
 \code{colours} vector. See \code{\link{rescale}} for a convience function
@@ -73,14 +80,18 @@ d + scale_colour_brewer(expression(clarity[beta]))
 d + scale_colour_brewer(type = "seq")
 d + scale_colour_brewer(type = "seq", palette = 3)
 
-d + scale_colour_brewer(palette = "Blues")
+d + scale_colour_brewer(palette = "Greens")
 d + scale_colour_brewer(palette = "Set1")
 
 # scale_fill_brewer works just the same as
 # scale_colour_brewer but for fill colours
-ggplot(diamonds, aes(x = price, fill = cut)) +
-  geom_histogram(position = "dodge", binwidth = 1000) +
-  scale_fill_brewer()
+p <- ggplot(diamonds, aes(x = price, fill = cut)) +
+  geom_histogram(position = "dodge", binwidth = 1000)
+p + scale_fill_brewer()
+# the order of colour can be reversed
+p + scale_fill_brewer(direction = -1)
+# the brewer scales look better on a darker background
+p + scale_fill_brewer(direction = -1) + theme_dark()
 
 # Generate map data
 library(reshape2) # for melt
@@ -95,7 +106,6 @@ v + scale_fill_distiller()
 v + scale_fill_distiller(palette = 2)
 v + scale_fill_distiller(type = "div")
 v + scale_fill_distiller(palette = "Spectral")
-v + scale_fill_distiller(palette = "Spectral", trans = "reverse")
 v + scale_fill_distiller(type = "qual")
 # Not appropriate for continuous data, issues a warning
 }