Re: [csswg-drafts] [css-color-4] Premultiplication in cylindrical spaces and mixing (#11238)

Yes, if this was truly desired, scaling the progress for hues would likely be the best way forward. Of course, this would be an exception and not premultiplication. If this was done, I think it would make sense to distinguish it as an exception for hues that applies "alpha-weighting" as opposed to "premultiplication".

One would need to handle the cases were the denominator is zero. Some pseudocode.

```js
if (index == hue_index) {
      denom = progress * end_alpha + (1 - progress) * start_alpha;
      p = (denom) ? (point * end_alpha) / denom : point;
      c = lerp(a, b, p);
}
```

This is not an exhaustive test, but it appears to do what was desired:

<img width="1209" alt="Screenshot 2024-11-28 at 8 36 45 AM" src="https://github.com/user-attachments/assets/d51b7980-aeff-485f-8507-ee8c3a33b26b">








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Received on Thursday, 28 November 2024 15:41:22 UTC