The goal of farver is to provide very fast, vectorised conversion of colours between different colour spaces, as well as provide fast colour comparisons (distance between colours). To this end it provides an interface to a modified version of the ColorSpace C++ library developed by Berendea Nicolae.
farver is currently only available on Github, but will be released on CRAN once it has reached a stable state. For now, install using devtools:
# install.packages('devtools')
devtools::install_github('thomasp85/farver')The main functions of the package isareconvert_colour() with an interface very much alike grDevices::convertColor(), and compare_colour() which allows you to calculate the distance between colours using different metrics
library(farver)
spectrum <- t(col2rgb(rainbow(10)))
spectrum
#> red green blue
#> [1,] 255 0 0
#> [2,] 255 153 0
#> [3,] 204 255 0
#> [4,] 51 255 0
#> [5,] 0 255 102
#> [6,] 0 255 255
#> [7,] 0 102 255
#> [8,] 51 0 255
#> [9,] 204 0 255
#> [10,] 255 0 153
convert_colour(spectrum, 'rgb', 'lab')
#> [,1] [,2] [,3]
#> [1,] 53.24079 80.09246 67.203197
#> [2,] 72.26072 30.16539 77.224482
#> [3,] 93.60533 -41.94504 90.274226
#> [4,] 88.07403 -83.10813 83.593379
#> [5,] 88.19634 -80.27943 57.926987
#> [6,] 91.11322 -48.08753 -14.131186
#> [7,] 47.90478 35.19678 -82.006104
#> [8,] 33.81896 79.70044 -105.279006
#> [9,] 51.90416 90.99470 -74.834222
#> [10,] 55.65103 86.52861 -9.719051spectrum2 <- t(col2rgb(heat.colors(10)))
compare_colour(spectrum, spectrum2, 'rgb', method = 'cie2000')[1:6, 1:6]
#> [,1] [,2] [,3] [,4] [,5] [,6]
#> [1,] 0.00000 1.950705 7.131114 15.53888 27.083292 39.89086
#> [2,] 29.50183 27.566791 22.403383 13.98164 2.416093 10.31364
#> [3,] 72.33700 70.330572 64.926952 55.98589 43.599157 30.24633
#> [4,] 85.84641 83.687702 77.853543 68.19825 55.060776 41.58806
#> [5,] 85.92047 83.796852 78.072403 68.67013 56.074572 43.42730
#> [6,] 70.95912 69.553268 65.907408 60.35762 53.722352 47.94419farver currently supports the following colour spaces:
- CMY
- CMYK
- HSL
- HSB
- HSV
- CIE L*AB
- Hunter LAB
- LCH
- LUV
- RGB
- XYZ
- YXY
farver is substantially faster than its grDevices counterpart as all operation happens in compiled code:
library(ggplot2)
library(microbenchmark)
test <- matrix(sample(256L, 30000, TRUE), ncol = 3) - 1L
timing <- microbenchmark(
farver = convert_colour(test, 'rgb', 'lab'),
grDevices = convertColor(test, 'sRGB', 'Lab', scale.in = 255)
)
autoplot(timing)
Currently farver does not allow setting custom white points for the input and output colour spaces. Hopefully this will be added at a later stage.
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