[WIP] Add ggridges

DESCRIPTION

@@ -56,7 +56,8 @@ Suggests:
     rmarkdown,
     roxygen2,
     testthat,
-    crosstalk
+    crosstalk,
+    ggridges
 Roxygen: list(wrap = FALSE)
 RoxygenNote: 6.0.1
 VignetteBuilder: packagedocs

NAMESPACE

@@ -24,6 +24,7 @@ export(ggally_box_no_facet)
 export(ggally_cor)
 export(ggally_density)
 export(ggally_densityDiag)
+export(ggally_density_ridges)
 export(ggally_denstrip)
 export(ggally_diagAxis)
 export(ggally_dot)

R/gg-plots.R

@@ -1373,3 +1373,33 @@ ggally_na <- function(data = NULL, mapping = NULL, size = 10, color = "grey20",
 ggally_naDiag <- function(...) {
   ggally_na(...)
 }
+
+#' Create a ridgeline plot.
+#'
+#' `ggally_density_ridges` generates a ridgeline plot with partially overlapping line plots that create the impression of a mountain range. They can be quite useful for visualizing changes in distributions over time or space.
+#'
+#' @param data The data set used.
+#' @param mapping The aesthetics used.
+#' @param ... Other parameters passed on to \code{\link[ggridges]{geom_density_ridges2}}.
+#'
+#' @examples
+#'   data(iris)
+#'   ggpairs(iris, lower = list("combo" = ggally_density_ridges))
+#'   ggpairs(iris, lower = list("combo" = ggally_density_ridges, mapping = ggplot2::aes(color = Species)))
+#'   ggpairs(iris, lower = list("combo" = wrap(ggally_density_ridges, rel_min_height = 0.01), mapping = ggplot2::aes(color = Species)))
+#'
+#' @author Jens Preussner \email{jens.preussner@@mpi-bn.mpg.de}
+#' @export
+ggally_density_ridges <- function(data, mapping, ..., scale = 1) {
+  require_namespaces("ggridges")
+  horizontal <- GGally:::is_horizontal(data, mapping)
+
+  if (!horizontal) {
+    mapping <- GGally:::mapping_swap_x_y(mapping)
+  }
+
+  mapping <- GGally:::mapping_color_to_fill(mapping)
+
+  ggplot2::ggplot(data) +
+    ggridges::geom_density_ridges2(mapping, ..., scale = scale)
+}

R/ggpairs_internal_plots.R

@@ -109,7 +109,7 @@ wrap_fn_with_param_arg <- function(
 "The following ggpairs plot functions are readily available: \n",
 "\tcontinuous: c('points', 'smooth', 'smooth_loess', 'density', 'cor', 'blank')\n",
 "\tcombo: c('box', 'box_no_facet', 'dot', 'dot_no_facet', 'facethist',",
-  " 'facetdensity', 'denstrip', 'blank')\n",
+  " 'facetdensity', 'denstrip', 'density_ridges', 'blank')\n",
 "\tdiscrete: c('ratio', 'facetbar', 'blank')\n",
 "\tna: c('na', 'blank')\n",
 "\n",

tests/testthat/test-zzz_ggpairs.R

@@ -633,7 +633,7 @@ test_that("subtypes", {
   # re ordered the subs so that density can have no binwidth param
   conSubs <- list("density", "points", "smooth", "smooth_loess", "cor", "blank")
   comSubs <- list(
-    "box", "dot", "box_no_facet", "dot_no_facet",
+    "box", "dot", "box_no_facet", "dot_no_facet", "density_ridges",
     wrap("facethist", binwidth = 1),
     "facetdensity", wrap("denstrip", binwidth = 1),
     "blank"