Re: [csswg-drafts] [css-color-4] [css-color-5] inconsistent mentions of powerless components in `white`. (#8609)

So, I've actually taken a closer look at this. If powerless means that interpolation should treat the components as missing, I think the current CSS spec is heading in a confusing direction. Let's take a look.

Here we create two OkLCh colors `oklch(1 0 none)` and `oklch(1 none none)`. The first matches white yields the results in the CSS spec which I believe was added before the stipulation that 0% and 100% lightness make chroma powerless. The latter matches the powerless suggestions in the spec and also matches @romainmenke's assertion that the proper OkLCh output should be `oklch(72.601% 0.31321 264.052)`. But notices how the powerless hue makes the blue more purple.

<img width="625" alt="Screenshot 2023-03-29 at 11 23 28 AM" src="https://user-images.githubusercontent.com/1055125/228619080-635c71fb-e0ed-4fba-bb04-de30097e1b24.png">

But let's look at the entire interpolation:

<img width="1365" alt="Screenshot 2023-03-29 at 11 26 55 AM" src="https://user-images.githubusercontent.com/1055125/228619507-610db4a6-6fe7-4a40-92c0-fd4d70a70ea9.png">

Oh, no, now we have a huge shift in color. This defeats the whole purpose of using OkLCh! What happens if we use black?

<img width="1355" alt="Screenshot 2023-03-29 at 11 30 57 AM" src="https://user-images.githubusercontent.com/1055125/228620612-1cd60153-58ce-4c23-8dde-0423e57302ad.png">

Just as bad.

So, why do we want chroma as powerless treated as missing for black and white during interpolation?




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Received on Wednesday, 29 March 2023 17:52:29 UTC