Viridis color palette from ggplot2 v. 3.0.0 cloned here

DESCRIPTION

@@ -1,15 +1,15 @@
 Package: chart
 Type: Package
-Version: 1.1.0
+Version: 1.2.0
 Title: General Charting (Plotting) Function
 Description: Chart generalizes plot generation in R, being with base R plot
   function, lattice or ggplot2. A formula interface is available for both.
 Authors@R: c(person("Philippe", "Grosjean", role = c("aut", "cre"),
   email = "phgrosjean@sciviews.org"))
 Maintainer: Philippe Grosjean <phgrosjean@sciviews.org>
 Depends: R (>= 3.3.0), lattice, ggplot2
-Imports: stats, utils, rlang, cowplot, grDevices, graphics, scales, latticeExtra, pryr, data.io, ggplotify, ggpubr
-Suggests: covr, knitr, testthat
+Imports: stats, utils, rlang, cowplot, grDevices, graphics, scales, latticeExtra, viridis, pryr, data.io, ggplotify, ggpubr
+Suggests: MASS, covr, knitr, testthat
 Remotes: SciViews/data.io
 Encoding: UTF-8
 ByteCompile: yes

NAMESPACE

@@ -8,6 +8,15 @@ export(chart_theme)
 export(combine_charts)
 export(f_aes)
 export(ggarrange)
+export(scale_color_continuous)
+export(scale_color_viridis_c)
+export(scale_color_viridis_d)
+export(scale_colour_continuous)
+export(scale_colour_viridis_c)
+export(scale_colour_viridis_d)
+export(scale_fill_continuous)
+export(scale_fill_viridis_c)
+export(scale_fill_viridis_d)
 export(theme_sciviews)
 export(theme_sciviews_graphics)
 export(theme_sciviews_lattice)
@@ -35,7 +44,9 @@ importFrom(rlang,f_lhs)
 importFrom(rlang,f_rhs)
 importFrom(rlang,is_true)
 importFrom(rlang,warn)
+importFrom(scales,gradient_n_pal)
 importFrom(scales,hue_pal)
 importFrom(stats,as.formula)
 importFrom(stats,asOneSidedFormula)
 importFrom(utils,modifyList)
+importFrom(viridis,viridis_pal)

NEWS.md

@@ -1,5 +1,11 @@
 # chart News
 
+## chart version 1.2.0
+
+- The functions to use viridis palettes in ggplot2 are cloned here from ggplot2
+  v. 3.0.0, in order to use them also with older ggplot2 plots.
+
+
 ## chart version 1.1.0
 
 - First implementation of base and lattice versions of `chart()`s.

R/chart-package.R

@@ -17,7 +17,8 @@
 #' @import lattice
 #' @importFrom latticeExtra custom.theme ggplot2like ggplot2like.opts
 #' @import ggplot2
-#' @importFrom scales hue_pal
+#' @importFrom viridis viridis_pal
+#' @importFrom scales hue_pal gradient_n_pal
 #' @importFrom cowplot theme_cowplot
 #' @importFrom rlang abort warn f_env f_lhs f_rhs is_true
 #' @importFrom stats as.formula asOneSidedFormula
@@ -36,6 +37,11 @@ NULL
   #ggplot2::theme_set(theme_sciviews())
   #theme_sciviews_lattice()
   #theme_sciviews_graphics()
+  # Use viridis continuous palettes by default with ggplot2 charts
+  if (is.null(getOption("ggplot2.continuous.fill")))
+    options(ggplot2.continuous.fill = "viridis")
+  if (is.null(getOption("ggplot2.continuous.colour")))
+    options(ggplot2.continuous.colour = "viridis")
 }
 
 `%is%` <- function(x, what) # This is more expressive!

R/chart_theme.R

@@ -159,6 +159,132 @@ theme_svmap_lattice <- function() {
 #' @rdname chart_theme
 theme_svmap_graphics <- function() NULL
 
+#' Viridis color scales
+#'
+#' ggplot2 version 3 add these function to include viridis color scales. These
+#' functions are cloned from ggplot2 v.3.0.0 in order to use the same color
+#' scheme with earlier versions of ggplot2. Note, however, that the options
+#' `ggplot2.continuous.fill` and `gplot2.continuous.colour` are set to
+#' `"viridis"` if not already specified. This changes the default for continuous
+#' colors in favor of viridis for both `ggplot()` and `chart()`.
+#'
+#' @param ... Other arguments passed on to [discrete_scale()] or
+#' [continuous_scale()] to control name, limits, breaks, labels and so forth.
+#' @param alpha The alpha transparency, a number in `[0,1]`, see argument alpha
+#' in hsv.
+#' @param begin The (corrected) hue in `[0,1]` at which the viridis colormap
+#' begins.
+#' @param end The (corrected) hue in `[0,1]` at which the viridis colormap ends.
+#' @param direction Sets the order of colors in the scale. If `1`, the default,
+#' colors are ordered from darkest to lightest. If `-1`, the order of colors is
+#' reversed.
+#' @param option A character string indicating the colormap option to use. Four
+#' options are available: `"magma"` (or `"A"`), `"inferno"` (or `"B"`),
+#' `"plasma"` (or `"C"`), `"viridis"` (or `"D"`, the default option) and
+#' `"cividis"` (or `"E"`).
+#' @param aesthetics Character string or vector of character strings listing the
+#' name(s) of the aesthetic(s) that this scale works with. This can be useful,
+#' for example, to apply colour settings to the colour and fill aesthetics at
+#' the same time, via `aesthetics = c("colour", "fill")`.
+#' @param 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
+#' colours vector. See rescale() in the scales package for a convience function
+#' to map an arbitrary range to between 0 and 1.
+#' @param space Colour space in which to calculate gradient. Must be "Lab" -
+#' other values are deprecated.
+#' @param na.value Missing values will be replaced with this value.
+#' @param guide A function used to create a guide or its name. See [guides()]
+#' for more info.
+#' @param type One of "gradient" or "viridis" indicating the colour scale to
+#' use. Can be changed with [options()], and the chart package set it to
+#' `"viridis"` in case it is not set yet when the package is attached.
+#'
+#' @export
+#' @seealso [chart()], [chart_theme()]
+#' @keywords color
+#' @name viridis
+#' @concept Viridis colors
+#' @examples
+#' geyser <- data.io::read("geyser", package = "MASS")
+#' chart(data = geyser, waiting ~ duration) +
+#'   xlim(0.5, 6) + ylim(40, 110) +
+#'   stat_density2d(aes(fill = ..level..), geom = "polygon") +
+#'   theme(panel.grid = element_blank()) -> gg
+#'
+#' combine_charts(
+#'   list(
+#'     gg + scale_fill_viridis_c(option = "A") + labs(x = "A = magma", y = NULL),
+#'     gg + scale_fill_viridis_c(option = "B") + labs(x = "B = inferno", y = NULL),
+#'     gg + scale_fill_viridis_c(option = "C") + labs(x = "C = plasma", y = NULL),
+#'     gg + scale_fill_viridis_c(option = "D") + labs(x = "D  = viridis", y = NULL),
+#'     gg + scale_fill_viridis_c(option = "E") + labs(x = "E = cividis", y = NULL)
+#'   ), ncol = 3, nrow = 2
+#' )
+scale_colour_viridis_c <- function(..., alpha = 1, begin = 0, end = 1,
+direction = 1, option = "D", values = NULL, space = "Lab", na.value = "grey50",
+guide = "colourbar", aesthetics = "colour") {
+  continuous_scale(aesthetics, "viridis_c", scales::gradient_n_pal(
+    viridis::viridis_pal(alpha, begin, end, direction, option)(6),
+    values, space), na.value = na.value, guide = guide, ...)
+}
+
+#' @export
+#' @rdname viridis
+scale_color_viridis_c <- scale_colour_viridis_c
+
+#' @export
+#' @rdname viridis
+scale_colour_viridis_d <- function(..., alpha = 1, begin = 0, end = 1,
+direction = 1, option = "D", aesthetics = "colour") {
+  discrete_scale(aesthetics, "viridis_d", viridis_pal(alpha,
+    begin, end, direction, option), ...)
+}
+
+#' @export
+#' @rdname viridis
+scale_color_viridis_d <- scale_colour_viridis_d
+
+#' @export
+#' @rdname 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", aesthetics = "fill") {
+  continuous_scale(aesthetics, "viridis_c", gradient_n_pal(
+    viridis_pal(alpha, begin, end, direction, option)(6),
+    values, space), na.value = na.value, guide = guide, ...)
+}
+
+#' @export
+#' @rdname viridis
+scale_fill_viridis_d <- function(..., alpha = 1, begin = 0, end = 1,
+direction = 1, option = "D", aesthetics = "fill") {
+  discrete_scale(aesthetics, "viridis_d", viridis_pal(alpha,
+    begin, end, direction, option), ...)
+}
+
+#' @export
+#' @rdname viridis
+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))
+}
+
+#' @export
+#' @rdname viridis
+scale_color_continuous <- scale_colour_continuous
+
+#' @export
+#' @rdname viridis
+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))
+}
 
 .sciviewslike_opts <- function() {
   list(default.args = list(axis = .axis_grid,