Set outline type for geom_density as geom_area (#3708)

Author: thomasp85

R/geom-density.r

@@ -12,6 +12,7 @@
 #'   See [geom_violin()] for a compact density display.
 #' @inheritParams layer
 #' @inheritParams geom_bar
+#' @inheritParams geom_ribbon
 #' @param geom,stat Use to override the default connection between
 #'   `geom_density` and `stat_density`.
 #' @export
@@ -56,7 +57,9 @@ geom_density <- function(mapping = NULL, data = NULL,
                          na.rm = FALSE,
                          orientation = NA,
                          show.legend = NA,
-                         inherit.aes = TRUE) {
+                         inherit.aes = TRUE,
+                         outline.type = "upper") {
+  outline.type <- match.arg(outline.type, c("both", "upper", "lower", "legacy"))
 
   layer(
     data = data,
@@ -69,6 +72,7 @@ geom_density <- function(mapping = NULL, data = NULL,
     params = list(
       na.rm = na.rm,
       orientation = orientation,
+      outline.type = outline.type,
       ...
     )
   )

man/geom_density.Rd

@@ -14,8 +14,8 @@ test_that("geom_xxx and GeomXxx$draw arg defaults match", {
   geom_fun_names <- setdiff(
     geom_fun_names,
     c("geom_map", "geom_sf", "geom_smooth", "geom_column", "geom_area",
-      "annotation_custom", "annotation_map",
-      "annotation_raster", "annotation_id")
+      "geom_density", "annotation_custom", "annotation_map", "annotation_raster",
+      "annotation_id")
   )
 
   # For each geom_xxx function and the corresponding GeomXxx$draw and