Add built-in support for viridis color scales (#2178)

* Begin viridis scales

* Add to NEWS.md

* Add documentation for continuous_scale parameters na.value and guide

* Remove @description

* tidyverse style for long calls to discrete_scale/continuous_scale

oops

* Use markdown url syntax

* viridis_pal is now in the scales package

* Shorten names to viridis_c and viridis_d

* Add viridis examples based on the brewer examples

* Add viridis tests

* Update viridis tests

* Use global options to control default continuous colour/fill scales

* Don't set options in .onLoad()

* Put closing paren on new line

* Update NEWS.md

Author: karawoo

DESCRIPTION

@@ -43,7 +43,8 @@ Suggests:
     rpart,
     rmarkdown,
     sf (>= 0.3-4),
-    svglite (>= 1.2.0.9001)
+    svglite (>= 1.2.0.9001),
+    viridisLite
 Remotes:
     hadley/scales,
     hadley/svglite
@@ -169,6 +170,7 @@ Collate:
     'scale-.r'
     'scale-alpha.r'
     'scale-brewer.r'
+    'scale-colour.r'
     'scale-continuous.r'
     'scale-date.r'
     'scale-discrete-.r'
@@ -181,6 +183,7 @@ Collate:
     'scale-shape.r'
     'scale-size.r'
     'scale-type.R'
+    'scale-viridis.r'
     'scales-.r'
     'sf.R'
     'stat-bin.r'

NAMESPACE

@@ -385,6 +385,8 @@ export(scale_color_grey)
 export(scale_color_hue)
 export(scale_color_identity)
 export(scale_color_manual)
+export(scale_color_viridis_c)
+export(scale_color_viridis_d)
 export(scale_colour_brewer)
 export(scale_colour_continuous)
 export(scale_colour_date)
@@ -398,6 +400,8 @@ export(scale_colour_grey)
 export(scale_colour_hue)
 export(scale_colour_identity)
 export(scale_colour_manual)
+export(scale_colour_viridis_c)
+export(scale_colour_viridis_d)
 export(scale_fill_brewer)
 export(scale_fill_continuous)
 export(scale_fill_date)
@@ -411,6 +415,8 @@ export(scale_fill_grey)
 export(scale_fill_hue)
 export(scale_fill_identity)
 export(scale_fill_manual)
+export(scale_fill_viridis_c)
+export(scale_fill_viridis_d)
 export(scale_linetype)
 export(scale_linetype_continuous)
 export(scale_linetype_discrete)

NEWS.md

@@ -1,5 +1,14 @@
 # ggplot2 2.2.1.9000
 
+* Default colour maps for continuous data are controlled by global options
+  `ggplot2.continuous.colour` and `ggplot2.continuous.fill`, which can be set to
+  either `"gradient"` or `"viridis"` (@karawoo).
+
+* Adds built-in support for `viridis` and related colour maps. Use the functions
+  `scale_colour_viridis_c()`/`scale_fill_viridis_c()` for continuous data and
+  `scale_colour_viridis_d()`/`scale_fill_viridis_d()` for discrete data
+  (@karawoo, #1526).
+
 * Updated datetime scales for `alpha`, `size`, `colour`, and `fill` can take
   `date_breaks` and `date_labels` arguments (@karawoo, #1526).
 

R/scale-colour.r

@@ -0,0 +1,46 @@
+#' Continuous colour scales
+#'
+#' Colour scales for continuous data default to the values of the
+#' `ggplot2.continuous.colour` and `ggplot2.continuous.fill` options. If these
+#' options are not present, `"gradient"` will be used. See [options()] for more
+#' information.
+#' 
+#' @param ... Additional parameters passed on to the scale type
+#' @param type One of "gradient" (the default) or "viridis" indicating the
+#'   colour scale to use
+#' @seealso [scale_colour_gradient()], [scale_colour_viridis_c()],
+#'   [scale_fill_gradient()], and [scale_fill_viridis_c()]
+#' @export
+#' @rdname scale_colour_continuous
+#' @examples
+#' v <- ggplot(faithfuld, aes(waiting, eruptions, fill = density)) +
+#' geom_tile()
+#' v
+#' 
+#' v + scale_fill_continuous(type = "gradient")
+#' v + scale_fill_continuous(type = "viridis")
+#' 
+#' # The above are equivalent to
+#' v + scale_fill_gradient()
+#' v + scale_fill_viridis_c()
+scale_colour_continuous <- function(...,
+                                    type = getOption("ggplot2.continuous.colour", default = "gradient")) {
+  switch(
+    type,
+    gradient = scale_colour_gradient(...),
+    viridis = scale_colour_viridis_c(...),
+    stop("Unknown scale type", call. = FALSE)
+  )
+}
+
+#' @rdname scale_colour_continuous
+#' @export
+scale_fill_continuous <- function(...,
+                                  type = getOption("ggplot2.continuous.fill", default = "gradient")) {
+  switch(
+    type,
+    gradient = scale_fill_gradient(...),
+    viridis = scale_fill_viridis_c(...),
+    stop("Unknown scale type", call. = FALSE)
+  )
+}

R/scale-viridis.r

@@ -0,0 +1,105 @@
+#' Viridis colour scales from viridisLite
+#'
+#' The `viridis` scales provide color maps that are perceptually uniform in both
+#' color and black-and-white. They are also designed to be perceived by viewers
+#' with common forms of color blindness. See also
+#' <https://bids.github.io/colormap/>.
+#' 
+#' @inheritParams viridisLite::viridis
+#' @inheritParams scales::gradient_n_pal
+#' @inheritParams continuous_scale
+#' @param ... Other arguments passed on to [discrete_scale()] or
+#' [continuous_scale()] to control name, limits, breaks, labels and so forth.
+#' @family colour scales
+#' @rdname scale_viridis
+#' @export
+#' @examples
+#' dsamp <- diamonds[sample(nrow(diamonds), 1000), ]
+#' (d <- ggplot(dsamp, aes(carat, price)) +
+#'   geom_point(aes(colour = clarity)))
+#' d + scale_colour_viridis_d()
+#'
+#' # Change scale label
+#' d + scale_colour_viridis_d("Diamond\nclarity")
+#'
+#' # Select palette to use, see ?scales::viridis_pal for more details
+#' d + scale_colour_viridis_d(option = "plasma")
+#' d + scale_colour_viridis_d(option = "inferno")
+#'
+#' \donttest{
+#' # scale_fill_viridis_d works just the same as
+#' # scale_colour_viridis_d but for fill colours
+#' p <- ggplot(diamonds, aes(x = price, fill = cut)) +
+#'   geom_histogram(position = "dodge", binwidth = 1000)
+#' p + scale_fill_viridis_d()
+#' # the order of colour can be reversed
+#' p + scale_fill_viridis_d(direction = -1)
+#' }
+#'
+#' # Use viridis_c with continous data
+#' v <- ggplot(faithfuld) +
+#'   geom_tile(aes(waiting, eruptions, fill = density))
+#' v
+#' v + scale_fill_viridis_c()
+#' v + scale_fill_viridis_c(option = "plasma")
+scale_colour_viridis_d <- function(..., alpha = 1, begin = 0, end = 1,
+                                   direction = 1, option = "D") {
+  discrete_scale(
+    "colour",
+    "viridis_d",
+    viridis_pal(alpha, begin, end, direction, option),
+    ...
+  )
+}
+
+#' @export
+#' @rdname scale_viridis
+scale_fill_viridis_d <- function(..., alpha = 1, begin = 0, end = 1,
+                                 direction = 1, option = "D") {
+  discrete_scale(
+    "fill",
+    "viridis_d",
+    viridis_pal(alpha, begin, end, direction, option),
+    ...
+  )
+}
+
+#' @export
+#' @rdname scale_viridis
+scale_colour_viridis_c <- function(..., alpha = 1, begin = 0, end = 1,
+                                   direction = 1, option = "D", values = NULL,
+                                   space = "Lab", na.value = "grey50",
+                                   guide = "colourbar") {
+  continuous_scale(
+    "colour",
+    "viridis_c",
+    gradient_n_pal(
+      viridis_pal(alpha, begin, end, direction, option)(6),
+      values,
+      space
+    ),
+    na.value = na.value,
+    guide = guide,
+    ...
+  )
+}
+
+#' @export
+#' @rdname scale_viridis
+scale_fill_viridis_c <- function(..., alpha = 1, begin = 0, end = 1,
+                                 direction = 1, option = "D", values = NULL,
+                                 space = "Lab", na.value = "grey50",
+                                 guide = "colourbar") {
+  continuous_scale(
+    "fill",
+    "viridis_c",
+    gradient_n_pal(
+      viridis_pal(alpha, begin, end, direction, option)(6),
+      values,
+      space
+    ),
+    na.value = na.value,
+    guide = guide,
+    ...
+  )
+}

R/zxx.r

@@ -5,11 +5,6 @@
 #' @usage NULL
 scale_colour_discrete <- scale_colour_hue
 
-#' @export
-#' @rdname scale_gradient
-#' @usage NULL
-scale_colour_continuous <- scale_colour_gradient
-
 #' @export
 #' @rdname scale_gradient
 #' @usage NULL
@@ -53,11 +48,6 @@ scale_colour_date <- function(...,
 #' @usage NULL
 scale_fill_discrete <- scale_fill_hue
 
-#' @export
-#' @rdname scale_gradient
-#' @usage NULL
-scale_fill_continuous <- scale_fill_gradient
-
 #' @export
 #' @rdname scale_gradient
 #' @usage NULL
@@ -75,7 +65,6 @@ scale_fill_datetime <- function(...,
     guide = guide,
     ...
   )
-  
 }
 
 #' @export
@@ -154,3 +143,13 @@ scale_color_identity <- scale_colour_identity
 #' @rdname scale_manual
 #' @usage NULL
 scale_color_manual <- scale_colour_manual
+
+#' @export
+#' @rdname scale_viridis
+#' @usage NULL
+scale_color_viridis_d <- scale_colour_viridis_d
+
+#' @export
+#' @rdname scale_viridis
+#' @usage NULL
+scale_color_viridis_c <- scale_colour_viridis_c