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| author | Gaël Poupard <[email protected]> | 2020-03-27 16:37:59 +0100 |
|---|---|---|
| committer | Gaël Poupard <[email protected]> | 2020-05-20 09:49:18 +0200 |
| commit | 1b8bf5b56c77a60aab4c228aada7565f77db17ce (patch) | |
| tree | 0d7ad78371e4483826dab3ba96bf856c59e9363c | |
| parent | 2df63f4925c41df8ac26c79742ee86822ee0877f (diff) | |
| download | bootstrap-1b8bf5b56c77a60aab4c228aada7565f77db17ce.tar.xz bootstrap-1b8bf5b56c77a60aab4c228aada7565f77db17ce.zip | |
feat(color-contrast): ensure we return a contrasted enough color (light-first), the most contrasted one otherwise
| -rw-r--r-- | scss/_functions.scss | 35 |
1 files changed, 33 insertions, 2 deletions
diff --git a/scss/_functions.scss b/scss/_functions.scss index d93e33916..36108896a 100644 --- a/scss/_functions.scss +++ b/scss/_functions.scss @@ -97,12 +97,43 @@ $_luminance-list: .0008 .001 .0011 .0013 .0015 .0017 .002 .0022 .0025 .0027 .003 .0033 .0037 .004 .0044 .0048 .0052 .0056 .006 .0065 .007 .0075 .008 .0086 .0091 .0097 .0103 .011 .0116 .0123 .013 .0137 .0144 .0152 .016 .0168 .0176 .0185 .0194 .0203 .0212 .0222 .0232 .0242 .0252 .0262 .0273 .0284 .0296 .0307 .0319 .0331 .0343 .0356 .0369 .0382 .0395 .0409 .0423 .0437 .0452 .0467 .0482 .0497 .0513 .0529 .0545 .0561 .0578 .0595 .0612 .063 .0648 .0666 .0685 .0704 .0723 .0742 .0762 .0782 .0802 .0823 .0844 .0865 .0887 .0908 .0931 .0953 .0976 .0999 .1022 .1046 .107 .1095 .1119 .1144 .117 .1195 .1221 .1248 .1274 .1301 .1329 .1356 .1384 .1413 .1441 .147 .15 .1529 .1559 .159 .162 .1651 .1683 .1714 .1746 .1779 .1812 .1845 .1878 .1912 .1946 .1981 .2016 .2051 .2086 .2122 .2159 .2195 .2232 .227 .2307 .2346 .2384 .2423 .2462 .2502 .2542 .2582 .2623 .2664 .2705 .2747 .2789 .2831 .2874 .2918 .2961 .3005 .305 .3095 .314 .3185 .3231 .3278 .3325 .3372 .3419 .3467 .3515 .3564 .3613 .3663 .3712 .3763 .3813 .3864 .3916 .3968 .402 .4072 .4125 .4179 .4233 .4287 .4342 .4397 .4452 .4508 .4564 .4621 .4678 .4735 .4793 .4851 .491 .4969 .5029 .5089 .5149 .521 .5271 .5333 .5395 .5457 .552 .5583 .5647 .5711 .5776 .5841 .5906 .5972 .6038 .6105 .6172 .624 .6308 .6376 .6445 .6514 .6584 .6654 .6724 .6795 .6867 .6939 .7011 .7084 .7157 .7231 .7305 .7379 .7454 .7529 .7605 .7682 .7758 .7835 .7913 .7991 .807 .8148 .8228 .8308 .8388 .8469 .855 .8632 .8714 .8796 .8879 .8963 .9047 .9131 .9216 .9301 .9387 .9473 .956 .9647 .9734 .9823 .9911 1; @function color-contrast($background, $color-contrast-dark: $color-contrast-dark, $color-contrast-light: $color-contrast-light) { + $foregrounds: $color-contrast-light, $color-contrast-dark, $white, $black; + $contrast-ratios: (); + + @each $color in $foregrounds { + $contrast-ratio: contrast-ratio($background, $color); + @if $contrast-ratio > $min-contrast-ratio { + @return $color; + } @else { + $contrast-ratios: map-merge(($contrast-ratio: $color), $contrast-ratios); + } + } + + @warn "Found no color leading to #{$min-contrast-ratio}:1 contrast ratio against #{$background}…"; + + @return most-contrasted($contrast-ratios); +} + +@function contrast-ratio($background, $foreground: $color-contrast-light) { $l1: luminance($background); - $l2: luminance(opaque($background, $color-contrast-light)); + $l2: luminance(opaque($background, $foreground)); $contrast: if($l1 > $l2, ($l1 + .05) / ($l2 + .05), ($l2 + .05) / ($l1 + .05)); - @return if($contrast < $min-contrast-ratio, $color-contrast-dark, $color-contrast-light); + @return $contrast; +} + +// Returns the most contrasted color in a map of insufficiently contrasted colors +@function most-contrasted($contrast-ratios) { + $ratios: (); + + @each $ratio, $color in $contrast-ratios { + $ratios: append($ratios, $ratio); + } + + $highest-ratio: max($ratios...); + + @return map-get($contrast-ratios, $highest-ratio); } // Return WCAG2.0 relative luminance |