README.md

hsluv-rcpp

Rcpp implementation of HSLuv

Introduction

HSLuv is a human-friendly way to describe hue, saturation, and luminance --- three attributes of color. The library includes functions to convert this colorspace to computer RGB as separate red, green, and blue values and as a hex code.

Installation

To install, you will need a working toolchain on your computer for compiling C++ code, and the R package devtools installed. Once those are working, simply run the following code in an R session:

devtools::install_github("ssp3nc3r/hsluv-rcpp", ref = "master")

Examples

Once the package is installed, the functions can be used to map data to perceptually uniform color, like so:

library(HSLuv)

# Create sample data encoded as hue, saturation, luminance
df <- expand.grid(H = c(20, 290),
                  S = seq(0, 100, by = 10),
                  L = seq(0, 100, by = 10))

Then we can now graph colors encoded with said data in several ways. Here's a ggplot2 approach using scale_fill_identity() and hsluv_hex() within the aes():

library(ggplot2)

ggplot(df) +
  theme_minimal() +
  theme(panel.grid = element_blank(),
        axis.text.x.top = element_blank()) + 
  scale_fill_identity() +
  geom_point(
    mapping = aes(
      x = L, 
      y = S, 
      fill = hsluv_hex(H, S, L)), 
    color = '#eeeeee', 
    size = 10, 
    shape = 22) +
  scale_x_continuous(
    breaks = seq(0, 100, by = 20),
    sec.axis = sec_axis(~., name = 'Hue')) +
  scale_y_continuous(
    breaks = seq(0, 100, by = 20)) + 
  facet_wrap(~H) +
  labs(x = 'Luminance',
       y = 'Saturation')

returns,