[csswg-drafts] [css-color-5] Percent normalization does not account for computed zero percentages (#6890)

svgeesus has just created a new issue for https://github.com/w3c/csswg-drafts:

== [css-color-5] Percent normalization does not account for computed zero percentages ==
[The spec says](https://drafts.csswg.org/css-color-5/#color-mix)

- Percentages are required to be in the range 0% to 100%. Negative percentages are specifically disallowed.
- Otherwise, if p2 is omitted, it becomes 100% - p1
- Otherwise, if p1 is omitted, it becomes 100% - p2

So if I type

```css
color-mix(in lch, purple 80%, plum -30%)
```

it is invalid per spec, but if I instead go


```css
color-mix(in lch, purple 120%, plum )
```

then `p2` computes to -20% and the spec is silent on what do do next because only `p1` was specified and

- Otherwise, if both are provided and add up to greater than 100%, they are scaled accordingly so that they add up to 100%.

but they weren't both specified.

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/6890 using your GitHub account


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Received on Wednesday, 15 December 2021 22:41:51 UTC