LAB incorrectly converted

[strarsis]

LAB colour: 60, -28, -32
RGB (converted): 0, 160, 200

const one = require('onecolor');
var color = one([ 'LAB', 60, -28, -32 ]);
console.log(color.css());

Output:

rgb(93,93,93)

The calculated RGB value of 93, 93, 93 results in different colour (visually) and
also doesn't match the expected RGB value of 0, 160, 200.

[Munter]

Lab and xyz color spaces are not well tested, and thus marked as experimental so far.

If you have actually will known conversions that should work and have any reference to the correct color math I would be very happy to take a look at revisiting these.

A PR with failing color conversions would be very helpful as well

[papandreou]

I don't know anything about the LAB colorspace, but there must be something fishy. Conversions from rgb to lab and back again don't result in the same color, unless you dial up the epsilon way up:

oneColor('rebeccapurple').lab().rgb().equals(oneColor('rebeccapurple'), .2) // false
oneColor('rebeccapurple').lab().rgb().equals(oneColor('rebeccapurple'), .3) // true

[strarsis]

@Munter: For the example above I just used some online converters like https://www.nixsensor.com/free-color-converter/.
I noticed this issue with basically all input lab colours, hence I think there is a systematic issue.

[Munter]

I wouldn't be surprised that it's completely broken. Both XYZ and LAB were me just implementing it from a maths page without having any form of conversion examples I could plug in for testing.

There's also the problem that you have to choose a reference whitepoint (https://github.com/One-com/one-color/blob/master/lib/XYZ.js#L14-L21) and all examples I could find differ greatly. So I simply had no idea how to make a correct implementation and where to find any resource that would be considered correct