wessberg / color Goto Github PK

Hi Frederik, thanks for creating this library - I'm currently using it in a TypeScript project and the API is really nice.

I'm trying to lighten a black color, but it remains black:

const {lighten} = require("@wessberg/color")
console.log(lighten('black', 10)) // => '#000000'
console.log(lighten('#000000', 10)) // => '#000000'

(check it out on Runkit)

It works just fine for other colors.

I had a look at the source for lightenHsl, and the lightness is calculated as follows:

Math.max(0, Math.min(100, ((100 + percentage) * parseFloat(L)) / 100))

(where percentage = 10)

For black, L = 0, so the resulting lightness value is 0.
For L = 50, the resulting lightness is 55.

In general, it seems strange that the percentage is proportional to the existing lightness value, because colors that are already light will become much lighter than darker colors. I expected the lightness to simply be added to the existing lightness, ie. that

for L = 0, the resulting lightness would be 10,
and for L = 50 it would be 60.

in JS:

Math.max(0, Math.min(100, parseFloat(L) + percentage))

This change would obviously affect all of the colors generated by your library so I don't know if this is something you'd want to do if you're relying on the way specific colors look already - just wanted to flag this as I'll unfortunately have to use a different library for the time being.

Anyway let me know if this makes sense & if you'd consider changing the behavior. Thanks a lot :)