[css-color-4] set chroma to 0 when converting powerless hue to missing - #14244
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romainmenke
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July 31, 2026 15:15
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Looks good; one suggested link
Co-authored-by: Chris Lilley <chris@w3.org>
romainmenke
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Jul 31, 2026
| When changing a powerless hue component to a [=missing component=], | ||
| the chroma (or other measure of colorfulness, such as saturation in ''hsl''; see [=analogous components=]) is set to zero | ||
| to avoid amplifying floating-point noise. | ||
| In the case of ''hwb'' set ''b'' to ''100 - w'' or if either ''b'' or ''w'' is missing set the other component to ''100''. |
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For hwb this must only be done when W + B >= 99.999 and W + B < 100 to avoid clamping.
Maybe clearer in pseudo code than in prose?
1. if `w` + `b` is greater than `99.999` and `w` + `b` is less than `100`
2. if `w` and `b` are not missing
2.1. set `b` to `100 - w`
3. else if `w` is not missing
3.1. set `w` to `100`
4. else if `b` is not missing
4.1. set `b` to `100`
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Yes, that is much clearer
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The if condition on 1. covers 2. to 4. if true, right?
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Yes
Maybe clearer:
1. if `w` + `b` is greater than `99.999` and less than `100` and `w` and `b` are not missing
...
Or:
1. if `w` + `b` is greater than `99.999` and `w` + `b` is less than `100`
1.1. if `w` and `b` are not missing
1.1.1. set `b` to `100 - w`
1.2. else if `w` is not missing
1.2.1. set `w` to `100`
1.3. else if `b` is not missing
1.3.1. set `b` to `100`
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I have applied the second option and also replaced 99.999 with ε.
I've also added a clarification that this step should only be applied for other color spaces between zero and ε.
romainmenke
marked this pull request as ready for review
August 14, 2026 07:00
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See: #14133 (comment)