Early draft explainer for contrast color lvl 6#1260
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diekus wants to merge 1 commit intoMicrosoftEdge:mainfrom
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Early draft explainer for contrast color lvl 6#1260diekus wants to merge 1 commit intoMicrosoftEdge:mainfrom
diekus wants to merge 1 commit intoMicrosoftEdge:mainfrom
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Early initial draft for contrast-color lvl 6
kbabbitt
reviewed
Mar 12, 2026
| ``` | ||
| With these being the available parameters: | ||
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| - `<color-role>`: `background` or `foreground`. Specifies the role of the base, known color. It is also necessary for some contrst algorithms. |
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| - `<color-role>`: `background` or `foreground`. Specifies the role of the base, known color. It is also necessary for some contrst algorithms. | |
| - `<color-role>`: `background` or `foreground`. Specifies the role of the base, known color. It is also necessary for some contrast algorithms. |
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| - `<color-role>`: `background` or `foreground`. Specifies the role of the base, known color. It is also necessary for some contrst algorithms. | ||
| - `<color>`: The base color that an author is looking to contrast against. | ||
| - `<contrast-algorithm>`: Which contrast calculation method to use (`auto`, `wcap`, `lstar`, `apca`, `weber` or `michelson`). |
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As someone who is not familiar with these different algorithms, I think it would be helpful to include brief information about them and why this particular set was chosen for inclusion.
| - `<color>`: The base color that an author is looking to contrast against. | ||
| - `<contrast-algorithm>`: Which contrast calculation method to use (`auto`, `wcap`, `lstar`, `apca`, `weber` or `michelson`). | ||
| - `<contrast-target>`: Follows the `prefers-contrast` media query syntax. (`auto` | `max` | `more` | `less` | `<custom-contrast-target>`). More, less and no-preference (auto) correlate with user preferences. Max is introduced to return black or white. | ||
| - `<custom-contrast-target>`: the desired contrast target ratio or a percentage. This ratio will fail or pass depending on the used algorithm to calculate contrast. Is is only used when the `<custom-contrast-target>` is set. |
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I'm not following this line. I'm reading that <custom-contrast-target> is used only when <custom-contrast-target> is set ... ?
| The proposed syntax is as follows: | ||
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| ```css | ||
| contrast-color() = contrast-color(<color-role>? <color> / <contrast-target> <contrast-algorithm> <color>#{2,}) |
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| contrast-color() = contrast-color(<color-role>? <color> / <contrast-target> <contrast-algorithm> <color>#{2,}) | |
| contrast-color() = contrast-color(<color-role>? <color> [ / <contrast-target>? <contrast-algorithm>? [ <color>#{2,} ]? ]? ) |
Two suggestions here:
- For back-compat with V1
contrast-color(), enclose the/and everything after it in[ ]?i.e. optional - Make the trailing terms optional for cases where an author only wants to specify certain features, or not
pick from a list but rather return a maximally contrasting color, make the candidate list optional
| ```css | ||
| body { | ||
| background: blue; | ||
| color: contrast-color(blue gold, orange, yellow); |
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| color: contrast-color(blue gold, orange, yellow); | |
| color: contrast-color(blue / gold, orange, yellow); |
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Early initial draft for contrast-color lvl 6