Suggestions regarding value = 0 and 10

[bryanhanson]

One thing that might be nice, from an aesthetic and teaching point of view, would be for functions like hue_slice to draw the pure black and pure white at the top and bottom of the plot. I think this would help people who are learning the munsell system. I see that these values are not included in munsell.map and so would have to be appended to the draw list manually.

On a related note, if one happens to ask for munsell colors using a vector of colors which includes value = 0 or value = 10 a warning is issued. Two different kinds of uses that produce different errors resulting from this are:

value_slice(10)

tf <- function(minHue = "5R", maxHue = "5R",
    minVal = 8, maxVal = 10, minChroma = 2, maxChroma = 6) {

    # Process arguments to formated colors
    hueMin <- which(mnsl_hues() == minHue)
    hueMax <- which(mnsl_hues() == maxHue)
    hues <- mnsl_hues()[hueMin:hueMax]
    hvc <- expand.grid(hue = hues, value = minVal:maxVal,
        chroma = seq(minChroma, maxChroma, by = 2))
    m <- paste(hvc$hue, " ", hvc$value, "/", hvc$chroma, sep = "")
    cat("m = \n")
    print(m)

    # Convert colors to hexadecimals for plotting
    gam <- in_gamut(m)
    cat("gam = \n")
    print(gam)
    fix <- fix_mnsl(m)
    cat("fix = \n")
    print(fix)
    mh <- mnsl(m, fix = TRUE)

    }

tf()

The error comes from in_gamut, I think when it looks up values in munsell.map there is a logic check which eliminates value = 10 since it is not in munsell.map and then the lengths are not as expected.
It would be a slightly nicer user experience if this condition was trapped and just a message issues, or it could be silently fixed.

[cwickham]

Good suggestions. The easiest way to solve the first was to include definitions for all hues at all values with chroma = 0. Then without any changes to the plotting code, hue_silce displays the grey scale (including white and black) on the right.

This also fixes the second point you make.

The new definitions are have the usual "N ?/?" names so you can't look up them up. I.e mnsl("5B 10/0") doesn't work. However you can fix them to get the right name (and hex code), i.e.

fix_mnsl("5B 10/0")
[1] "N 10/0"