hcv-color VS hsluv

Here's a potential solution to having consistent accessible color palettes in Koala: https://www.hsluv.org

If you want to take a step further, take a look into perceptually uniform color spaces, like HSL(uv) or LCh(uv).

Maxima enabled me to make my color space [HSLuv](https://www.hsluv.org/). I encoded CIELUV <-> RGB transformation functions into Maxima, ran `solve` and converted the output back into code. It's great to be able to commit [Maxima code](https://github.com/hsluv/hsluv/tree/master/math) into your repository and not leave the math as an "exercise to the reader".

If you want to make it more useful than a browser's built-in color picker, perhaps support other color spaces? Maybe HSLuv or CIE L*a*b*?

Chroma could be included, but as a minor criterion. When I look at color pickers that try to balance human perception against geometric simplicity like HSLuv and Okhsl, chroma is the property that gets distorted the most. Perceptual brightness and hue seem to be more important.

> Now, HSL isn't necessarily the best color mode to use in every situation; it tends to produce gradients that can be overly bright and vivid, because it doesn't take into account human perception.

Shout-out to to [HSLUV](https://www.hsluv.org/) which does exactly that.

I'm a little bit of a color freak. Allow me to leave some suggestions :)

- Picking from the 256 color pallete will likely give you colors with different brightness. This may hurt readability of darker colors on a dark background, and may make some color stand out unintentionally. Consider using something like HSLuv [1] to pick colors with the same lightness, then convert to the closest Xterm color [2].

- To make it obvious there is a gradient, I'd pick one lightness (assuming HSLuv) and one saturation (I usually stick to 100%), then pick a distance in hue for each step. For example if I expect to see a maximum of 7 steps on the screen at once, one way is to start at 0, then 30, then 60, etc. You may choose to go over 180, but keep in mind 360 will be the same as 0 so maybe stop at 240. Note how by picking adjacent colors from the table you are still picking a distance, but the distance is too small so it's hard to see.

- You may want to choose a different starting point than 0, and maybe different direction for the steps, depending on whether you want the colors to "mean" anything. For example red is commonly associated with warning, so you can arrange to have the top of the range aligned with red. Or arrange to avoid the red region if you don't want that association.

[1] https://www.hsluv.org/

Check out HSLuv as an alternative for UI design: https://www.hsluv.org/

HSLuv is a HSL alternative, which aims to maintain the perceived lightness of colors across the hue spektrum. It also includes a HPLuv variant, which additionally maintains saturation, at the cost of color coverage. Both are very useful for procedually generating or modifying colors. More Info: https://www.hsluv.org/comparison/