Add na.color support to gradient_n_pal, div_gradient_pal, seq_gradient_pal

R/pal-gradient.r

@@ -7,13 +7,15 @@
 #'   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.color The color to use for missing values. By default missing
+#'   values are left missing.
 #' @export
 
-gradient_n_pal <- function(colours, values = NULL, space = "Lab") {
+gradient_n_pal <- function(colours, values = NULL, space = "Lab", na.color = NA) {
   if (!identical(space, "Lab")) {
     lifecycle::deprecate_warn("0.3.0", "gradient_n_pal(space = 'only supports be \"Lab\"')")
   }
-  ramp <- colour_ramp(colours)
+  ramp <- colour_ramp(colours, na.color = na.color)
   force(values)
 
   function(x) {
@@ -49,8 +51,8 @@ gradient_n_pal <- function(colours, values = NULL, space = "Lab") {
 #' pal <- div_gradient_pal(low = mnsl(complement("10R 4/6"), fix = TRUE))
 #' image(r, col = pal(seq(0, 1, length.out = 100)))
 #' @importFrom munsell mnsl
-div_gradient_pal <- function(low = mnsl("10B 4/6"), mid = mnsl("N 8/0"), high = mnsl("10R 4/6"), space = "Lab") {
-  gradient_n_pal(c(low, mid, high), space = space)
+div_gradient_pal <- function(low = mnsl("10B 4/6"), mid = mnsl("N 8/0"), high = mnsl("10R 4/6"), space = "Lab", na.color = NA) {
+  gradient_n_pal(c(low, mid, high), space = space, na.color = na.color)
 }
 
 #' Sequential colour gradient palette (continuous)
@@ -66,6 +68,6 @@ div_gradient_pal <- function(low = mnsl("10B 4/6"), mid = mnsl("N 8/0"), high =
 #'
 #' library(munsell)
 #' show_col(seq_gradient_pal("white", mnsl("10R 4/6"))(x))
-seq_gradient_pal <- function(low = mnsl("10B 4/6"), high = mnsl("10R 4/6"), space = "Lab") {
-  gradient_n_pal(c(low, high), space = space)
+seq_gradient_pal <- function(low = mnsl("10B 4/6"), high = mnsl("10R 4/6"), space = "Lab", na.color = NA) {
+  gradient_n_pal(c(low, high), space = space, na.color = na.color)
 }