color_dissimilarity

commit 53ec0626fea9a977460cc332ba88d1df56a11679
parent 4a64535d7641b8076c37dcba7a4e34160d6f1b7e
Author: Eamon Caddigan <eamon.caddigan@gmail.com>
Date:   Wed,  8 Sep 2021 06:53:17 -0400

Function to create palette functions

Diffstat:
A
seq_dissim_palette.R
 | 
30
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1 file changed, 30 insertions(+), 0 deletions(-)
diff --git a/seq_dissim_palette.R b/seq_dissim_palette.R
@@ -0,0 +1,30 @@
+
+#' Sequential dissimilarity palette
+#'
+#' Returns a palette function that, given a number `n` will return a sequence of
+#' decreasingly dissimilar colors. If `n` is greater than the number of colors
+#' specified, it falls back to a color ramp (in the same order used for the
+#' sequence of dissimilar colors). If you definitely want a color ramp it's best
+#' to call that directly.
+#'
+#' @param cols A list of color names
+#' @param cvd A color vision deficiency
+#'
+#' @return A palette function
+#' @export
+#'
+#' @examples
+#' seq_dissim_palette(c('orangered2', 'dodgerblue4', 'black', 'white'))(3)
+#'
+#' seq_dissim_palette(c('orangered2', 'dodgerblue4', 'black', 'white'))(6)
+seq_dissim_palette <- function(cols, cvd = 'deuteranomaly') {
+  dissim_mat <- cvd_dissimilarity(cols, cvd)
+  color_sequence <- seq_dissim_colors(dissim_mat)
+
+  function(n) {
+    if (n <= length(cols))
+      cols[color_sequence[seq(n)]]
+    else
+      grDevices::colorRampPalette(cols[color_sequence], space = 'Lab')(n)
+  }
+}