Package import/suggest for munsell

[elong0527]

For riskmetric project, I am reviewing the dependency of scales package to understand the need to qualify scale package for regulatory purpose.

munsell is used to define default value for div_gradient_pal and seq_gradient_pal.

Is it possible to move munsell to suggest in DESCRIPTION file by using hex RGB representation for default value?

scales/R/pal-gradient.r

Line 50 in 7ab95e1

div_gradient_pal <- function(low = mnsl("10B 4/6"), mid = mnsl("N 8/0"), high = mnsl("10R 4/6"), space = "Lab") {

scales/R/pal-gradient.r

Line 67 in 7ab95e1

seq_gradient_pal <- function(low = mnsl("10B 4/6"), high = mnsl("10R 4/6"), space = "Lab") {

[clauswilke]

Is a munsell dependency needed at all? Even in the examples, the package is used only to generate a few colors, and no explanation is given for why these specific colors. In my opinion, mnsl(complement("10R 4/6"), fix = TRUE) is not particularly less obscure than "#2E6A70".

My vote would be for replacing all calls to mnsl() with straight RGB values. We can make a note in the code explaining how the RGB colors were generated, in case somebody is wondering in the future.

[hadley]

I don't have any strong preference, except that removing mnsl will be some work and offers no real gain. So if someone else does a PR, I'll review it, but I don't think it's worth keeping this issue open.

[teunbrand]

I think this dependency isn't needed and removing it will help keep {scales} somewhat more lightweight.

I'd also throw the idea out there to remove the viridisLite and RColorBrewer dependencies, as many of their palettes are already available in grDevices::hcl.colors() (see hcl.pals() for example). However, we actually generate palettes with these packages, so they aren't as painless to remove.