Last active
September 27, 2022 12:36
-
-
Save sgomes/9c03a58976b90e00f4172a510b9807fa to your computer and use it in GitHub Desktop.
[Using Sass to automatically pick text colors] #4 - step 2
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
/** | |
* Calculate the luminance for a color. | |
* See https://www.w3.org/TR/WCAG20-TECHS/G17.html#G17-tests | |
*/ | |
@function luminance($color) { | |
$red: nth($linear-channel-values, red($color) + 1); | |
$green: nth($linear-channel-values, green($color) + 1); | |
$blue: nth($linear-channel-values, blue($color) + 1); | |
@return .2126 * $red + .7152 * $green + .0722 * $blue; | |
} | |
/** | |
* Calculate the contrast ratio between two colors. | |
* See https://www.w3.org/TR/WCAG20-TECHS/G17.html#G17-tests | |
*/ | |
@function contrast($back, $front) { | |
$backLum: luminance($back) + .05; | |
$foreLum: luminance($front) + .05; | |
@return max($backLum, $foreLum) / min($backLum, $foreLum); | |
} | |
/** | |
* Determine whether to use dark or light text on top of given color. | |
* Returns black for dark text and white for light text. | |
*/ | |
@function choose-contrast-color($color) { | |
$lightContrast: contrast($color, white); | |
$darkContrast: contrast($color, black); | |
@if ($lightContrast > $darkContrast) { | |
@return white; | |
} | |
@else { | |
@return black; | |
} | |
} |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
👍