splot color contrast ratio — splot.colorcontrast • splot

Calculates the color contrast ratio between two sets of colors, as defined by the World Wide Web Consortium.

Usage

splot.colorcontrast(color, background = "#ffffff", plot = TRUE)

Arguments

color, background: A character vector of colors, or a matrix with RGB values across rows.
plot: Logical; if FALSE, will not plot the results.

Value

A list with entries for ratio (contrast ratio), AA (ratios of at least 4.5), and AAA (ratios of at least 7). Each entry contains a matrix with colors in rows and backgrounds in columns.

Examples

# check colors against dark and light backgrounds
splot.colorcontrast(c("#FF0000", "#00FF00", "#0000FF"), c("black", "white"))

#> $ratio
#>          black    white
#> #FF0000  5.252 3.998477
#> #00FF00 15.304 1.372190
#> #0000FF  2.444 8.592471
#> 
#> $AA
#>         black white
#> #FF0000  TRUE FALSE
#> #00FF00  TRUE FALSE
#> #0000FF FALSE  TRUE
#> 
#> $AAA
#>         black white
#> #FF0000 FALSE FALSE
#> #00FF00  TRUE FALSE
#> #0000FF FALSE  TRUE
#> 

# check contrast between colors
splot.colorcontrast(c("red", "green", "blue"), c("red", "green", "blue"))

#> $ratio
#>            red    green     blue
#> red   1.000000 2.913938 2.148936
#> green 2.913938 1.000000 6.261866
#> blue  2.148936 6.261866 1.000000
#> 
#> $AA
#>         red green  blue
#> red   FALSE FALSE FALSE
#> green FALSE FALSE  TRUE
#> blue  FALSE  TRUE FALSE
#> 
#> $AAA
#>         red green  blue
#> red   FALSE FALSE FALSE
#> green FALSE FALSE FALSE
#> blue  FALSE FALSE FALSE
#> 

# see when shades of a color cross thresholds on a given background
splot.colorcontrast(splot.color(1:10, seed = "#a388b5"), "#101010")

#> $ratio
#>          #101010
#> #A388B5 6.112743
#> #9980AA 5.457068
#> #9078A0 4.874875
#> #867095 4.317859
#> #7D688A 3.822943
#> #736080 3.365093
#> #695875 2.947918
#> #60506A 2.585055
#> #564860 2.257584
#> #4D4055 1.975381
#> 
#> $AA
#>         #101010
#> #A388B5    TRUE
#> #9980AA    TRUE
#> #9078A0    TRUE
#> #867095   FALSE
#> #7D688A   FALSE
#> #736080   FALSE
#> #695875   FALSE
#> #60506A   FALSE
#> #564860   FALSE
#> #4D4055   FALSE
#> 
#> $AAA
#>         #101010
#> #A388B5   FALSE
#> #9980AA   FALSE
#> #9078A0   FALSE
#> #867095   FALSE
#> #7D688A   FALSE
#> #736080   FALSE
#> #695875   FALSE
#> #60506A   FALSE
#> #564860   FALSE
#> #4D4055   FALSE
#>