Add codes argument to scale_[fill/colour]_discrete(), closes tidyverse#3826

Author: cpsievert

R/scale-hue.r

@@ -63,3 +63,38 @@ scale_fill_hue <- function(..., h = c(0, 360) + 15, c = 100, l = 65, h.start = 0
   discrete_scale(aesthetics, "hue", hue_pal(h, c, l, h.start, direction),
     na.value = na.value, ...)
 }
+
+
+#' @export
+#' @inheritParams scale_colour_hue
+#' @param codes a vector of color codes defining a qualitative color palette. These codes
+#' are used so long as the number of codes is greater or equal to the number of values they encode.
+scale_colour_discrete <- function(..., codes = okabeIto, h = c(0, 360) + 15, c = 100, l = 65, h.start = 0,
+                                  direction = 1, na.value = "grey50", aesthetics = "colour") {
+  discrete_scale(
+    aesthetics, "qualitative", qualitative_pal(codes, h, c, l, h.start, direction),
+    na.value = na.value, ...
+  )
+}
+
+#' @export
+#' @inheritParams scale_colour_discrete
+scale_fill_discrete <- function(..., codes = okabeIto, h = c(0, 360) + 15, c = 100, l = 65, h.start = 0,
+                                direction = 1, na.value = "grey50", aesthetics = "fill") {
+  discrete_scale(
+    aesthetics, "qualitative", qualitative_pal(codes, h, c, l, h.start, direction),
+    na.value = na.value, ...
+  )
+}
+
+qualitative_pal <- function(codes, h, c, l, h.start, direction) {
+  function(n) {
+    if (n <= length(codes)) {
+      codes[seq_len(n)]
+    } else {
+      scales::hue_pal(h, c, l, h.start, direction)(n)
+    }
+  }
+}
+
+okabeIto <- c("#E69F00", "#009E73", "#0072B2", "#CC79A7", "#999999", "#D55E00", "#F0E442", "#56B4E9")

R/zxx.r

@@ -1,10 +1,5 @@
 # Default scales -------------------------------------------------------------
 
-#' @export
-#' @rdname scale_hue
-#' @usage NULL
-scale_colour_discrete <- scale_colour_hue
-
 #' @export
 #' @rdname scale_viridis
 #' @usage NULL
@@ -64,11 +59,6 @@ scale_colour_date <- function(...,
 #' @usage NULL
 scale_color_date <- scale_colour_date
 
-#' @export
-#' @rdname scale_hue
-#' @usage NULL
-scale_fill_discrete <- scale_fill_hue
-
 #' @export
 #' @rdname scale_viridis
 #' @usage NULL
@@ -143,7 +133,7 @@ scale_color_binned <- scale_colour_binned
 #' @export
 #' @rdname scale_hue
 #' @usage NULL
-scale_color_discrete <- scale_colour_hue
+scale_color_discrete <- scale_colour_discrete
 
 #' @export
 #' @rdname scale_gradient