R/contrast.R

In dpcarballo/coloR: Various Tools for Working with Color

#' Calculates the minimum contrast between col and the colors specified in ...
#' @param col The color we want to compare. Hexcode, c(r,g,b), color
#' name as character and "color" class object are all supported.
#' @param ... All other colors that col will be compared to. Hexcode, c(r,g,b), color
#' name as character and "color" class object are all supported.
#' @return A number between 0 and 1, representing a measure for contrast.
#' @examples contrast("red", "blue")
#' contrast("red", "blue", "black", "green", "white")
#' contrast("blue", list("#000000", "brown", c(255, 0, 255), "pink", c(0, 128, 176)))
contrast <- function(col,...) {
  input <- dots_as_list(...)
  if(!is.numeric(col))
    col=get_rgb(col)
  input <- lapply(input, get_rgb)
  return(min(sapply(input,rgb_dist, col2=col)))
}