Complementary color trait for colors that have a Hue

[explosion-mental]

While switching/porting more stuff to palette, I've noticed It doesn't have a Complementary color feature. Not sure how useful or needed this is, but the crate does give you enough tools to implement it yourself.

I have a dead simple prototype, I'm sure yourself as the author could come up with something more sophisticated and/or find some issues with it.

https://codeberg.org/explosion-mental/wallust/src/commit/b023a478001a3ab66bafe77b087e6dd22dbeb44d/src/colors.rs#L236-L270

[Ogeon]

Thanks for bringing this up! It can be nice to have a dedicated trait for it, even if it can be accomplished with hue shifts. Especially if it's possible to implement for more types than those with explicit hue components. The meaning of the terminology needs to be nailed down, though. It looks like your implementation and the one in the linked stack overflow question are quite different, not to mention that you are dividing the hues into chunks.

[explosion-mental]

It looks like your implementation and the one in the linked stack overflow question are quite different, not to mention that you are dividing the hues into chunks.

Well that was because I was using easy_colors which didn't have anything like shift_hue(). Since shift_hue on the palette crate can understand and treats values within 0..=360 range (or some of it's siblings functions) a simple shift_hue(180) should suffice (and maybe even add other counterparts).

I was thinking of my implementation as this Newton's wheel (reminds me of the circle of fifths), so I wanted to preserve the distance that the color was positioned in the current arc, which shift_huw alrd does, since it adds/subtracts the amount to the hue (if i'm not mistaken).

As for the linked stack overflow, I'm not sure why they add/subtract 30, since in hsv it's defined (Complementary Colors - Wikipedia):

In some other color models, such as the HSV color space, the neutral colors (white, grays, and black) lie along a central axis. Complementary colors (as defined in HSV) lie opposite each other on any horizontal cross-section. For example, in the CIE 1931 color space a color of a "dominant" wavelength can be mixed with an amount of the complementary wavelength to produce a neutral color (gray or white).

[Ogeon]

I see, your use case may need something more hand crafted in the end. That's ok, and a trait for complementary colors is still valuable on its own.

I just wanted to be sure we are on the same page, and it seems like we both mean a 180 degree rotation. I.e. the Wikipedia definition. The stack overflow question is talking about "split complementary", which is two colors that are adjacent to the complementary. You will also see people talking about triadic, tetriadic and analogous colors. All of these could probably be traits for convenience.

[explosion-mental]

Sounds good. Would love to help but I think I'm not that knowledgeable on color theory. I'll be active thanks to the project I'm developing (and trying to reach a stable version) so don't mind my newbie questions :)

[Ogeon]

No worries! The basics are quite simple. I got around to implement the common color schemes in #384. The module documentation is still a bit sparse, but let me know if anything seems weird, in case you decide to have a look. 🙂