diff --git a/R/spec_tools.R b/R/spec_tools.R
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+#' Generate viridis Color code for continuous values
+#'
+#' @inheritParams viridisLite::viridis
+#' @param x continuous vectors of values
+#' @param na_color color code for NA values
+#' @export
+spec_color <- function(x, alpha = 1, begin = 0, end = 1,
+                       direction = 1, option = "D",
+                       na_color = "#BBBBBBFF") {
+  x <- round(rescale(x, c(1, 256)))
+  color_code <- viridisLite::viridis(256, alpha, begin, end, direction, option)[x]
+  color_code[is.na(color_code)] <- na_color
+  return(color_code)
+}
+
+#' Generate common font size for continuous values
+#'
+#' @param x continuous vectors of values
+#' @param begin Smalles font size to be used. Default is 10.
+#' @param end Largest font size. Default is 20.
+#' @param na_font_size font size for NA values
+#' @export
+spec_font_size <- function(x, begin = 10, end = 20, na_font_size = "inherit") {
+  x <- round(rescale(x, c(begin, end)))
+  x[is.na(x)] <- na_font_size
+  return(x)
+}
+
+#' Generate rotation angle for continuous values
+#'
+#' @param x continuous vectors of values
+#' @param begin Smallest degree to rotate. Default is 0
+#' @param end Largest degree to rotate. Default is 359.
+#' @export
+spec_angle <- function(x) {
+  x <- round(rescale(x, c(0, 359)))
+  x[is.na(x)] <- 0
+  return(x)
+}