using Colors, Plots
gr(legend = false, grid = false, ms = 10, msw = 0)
# the ANSI colors (minus the 16 first which are duplicates)
hexcodes = parse.([Colorant], ["#000000", "#00005f", "#000087", "#0000af", "#0000d7", "#0000ff", "#005f00", "#005f5f", "#005f87", "#005faf", "#005fd7", "#005fff", "#008700", "#00875f", "#008787", "#0087af", "#0087d7", "#0087ff", "#00af00", "#00af5f", "#00af87", "#00afaf", "#00afd7", "#00afff", "#00d700", "#00d75f", "#00d787", "#00d7af", "#00d7d7", "#00d7ff", "#00ff00", "#00ff5f", "#00ff87", "#00ffaf", "#00ffd7", "#00ffff", "#5f0000", "#5f005f", "#5f0087", "#5f00af", "#5f00d7", "#5f00ff", "#5f5f00", "#5f5f5f", "#5f5f87", "#5f5faf", "#5f5fd7", "#5f5fff", "#5f8700", "#5f875f", "#5f8787", "#5f87af", "#5f87d7", "#5f87ff", "#5faf00", "#5faf5f", "#5faf87", "#5fafaf", "#5fafd7", "#5fafff", "#5fd700", "#5fd75f", "#5fd787", "#5fd7af", "#5fd7d7", "#5fd7ff", "#5fff00", "#5fff5f", "#5fff87", "#5fffaf", "#5fffd7", "#5fffff", "#870000", "#87005f", "#870087", "#8700af", "#8700d7", "#8700ff", "#875f00", "#875f5f", "#875f87", "#875faf", "#875fd7", "#875fff", "#878700", "#87875f", "#878787", "#8787af", "#8787d7", "#8787ff", "#87af00", "#87af5f", "#87af87", "#87afaf", "#87afd7", "#87afff", "#87d700", "#87d75f", "#87d787", "#87d7af", "#87d7d7", "#87d7ff", "#87ff00", "#87ff5f", "#87ff87", "#87ffaf", "#87ffd7", "#87ffff", "#af0000", "#af005f", "#af0087", "#af00af", "#af00d7", "#af00ff", "#af5f00", "#af5f5f", "#af5f87", "#af5faf", "#af5fd7", "#af5fff", "#af8700", "#af875f", "#af8787", "#af87af", "#af87d7", "#af87ff", "#afaf00", "#afaf5f", "#afaf87", "#afafaf", "#afafd7", "#afafff", "#afd700", "#afd75f", "#afd787", "#afd7af", "#afd7d7", "#afd7ff", "#afff00", "#afff5f", "#afff87", "#afffaf", "#afffd7", "#afffff", "#d70000", "#d7005f", "#d70087", "#d700af", "#d700d7", "#d700ff", "#d75f00", "#d75f5f", "#d75f87", "#d75faf", "#d75fd7", "#d75fff", "#d78700", "#d7875f", "#d78787", "#d787af", "#d787d7", "#d787ff", "#d7af00", "#d7af5f", "#d7af87", "#d7afaf", "#d7afd7", "#d7afff", "#d7d700", "#d7d75f", "#d7d787", "#d7d7af", "#d7d7d7", "#d7d7ff", "#d7ff00", "#d7ff5f", "#d7ff87", "#d7ffaf", "#d7ffd7", "#d7ffff", "#ff0000", "#ff005f", "#ff0087", "#ff00af", "#ff00d7", "#ff00ff", "#ff5f00", "#ff5f5f", "#ff5f87", "#ff5faf", "#ff5fd7", "#ff5fff", "#ff8700", "#ff875f", "#ff8787", "#ff87af", "#ff87d7", "#ff87ff", "#ffaf00", "#ffaf5f", "#ffaf87", "#ffafaf", "#ffafd7", "#ffafff", "#ffd700", "#ffd75f", "#ffd787", "#ffd7af", "#ffd7d7", "#ffd7ff", "#ffff00", "#ffff5f", "#ffff87", "#ffffaf", "#ffffd7", "#ffffff", "#080808", "#121212", "#1c1c1c", "#262626", "#303030", "#3a3a3a", "#444444", "#4e4e4e", "#585858", "#626262", "#6c6c6c", "#767676", "#808080", "#8a8a8a", "#949494", "#9e9e9e", "#a8a8a8", "#b2b2b2", "#bcbcbc", "#c6c6c6", "#d0d0d0", "#dadada", "#e4e4e4", "#eeeeee"])
#our dusty blue
blue = parse(Colorant, "#7aa6da")
cd = colordiff.([blue], hexcodes)
scatter(cd, color = hexcodes)
scatter!([123], [-3], color = blue)
Now the y axis should delimit how close they are perceptually to our focal color, which is placed at the very bottom. Perceptually, I see lots of colors with colordiff values above 25 that are perceptually much more similar to the bottom point than many of the very bottom ones.
Is there something wrong with the colordiff function (or is it my eyes?).