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/* stylelint-disable scss/dollar-variable-pattern */
/* stylelint-disable scss/at-function-pattern */
@use 'sass:color';
@use 'sass:list';
@use 'sass:map';
@use 'sass:math';
$SA98G: (
mainTRC: 2.4,
sRco: 0.2126729,
sGco: 0.7151522,
sBco: 0.0721750,
normBG: 0.56,
normTXT: 0.57,
revTXT: 0.62,
revBG: 0.65,
blkThrs: 0.022,
blkClmp: 1.414,
scaleBoW: 1.14,
scaleWoB: 1.14,
loBoWoffset: 0.027,
loWoBoffset: 0.027,
deltaYmin: 0.0005,
loClip: 0.0001,
mFactor: 1.94685544331710,
mOffsetIn: 0.03873938165714010,
mExpAdj: 0.2833433964208690,
mOffsetOut: 0.3128657958707580,
);
@function apca_sRGB_to_Y($color) {
@return map.get($SA98G, sRco) * math.pow(math.div(color.red($color), 255), map.get($SA98G, mainTRC)) +
map.get($SA98G, sGco) * math.pow(math.div(color.green($color), 255), map.get($SA98G, mainTRC)) +
map.get($SA98G, sBco) * math.pow(math.div(color.blue($color), 255), map.get($SA98G, mainTRC));
}
@function apca_Y_to_sRGB($y) {
$c: math.round(math.pow($y, math.div(1, map.get($SA98G, mainTRC))) * 255);
@return rgb($c, $c, $c);
}
@function apcaContrast($txtY, $bgY) {
$icp: 0.0 1.1;
@if math.min($txtY, $bgY) < list.nth($icp, 1) or math.max($txtY, $bgY) > list.nth($icp, 2) {
@return 0;
}
@if $txtY <= map.get($SA98G, blkThrs) {
$txtY: $txtY + math.pow(map.get($SA98G, blkThrs) - $txtY, map.get($SA98G, blkClmp));
}
@if $bgY <= map.get($SA98G, blkThrs) {
$bgY: $bgY + math.pow(map.get($SA98G, blkThrs) - $bgY, map.get($SA98G, blkClmp));
}
@if math.abs($bgY - $txtY) < map.get($SA98G, deltaYmin) {
@return 0;
}
$outputContrast: 0;
@if $bgY > $txtY {
$SAPC: map.get($SA98G, scaleBoW) * (math.pow($bgY, map.get($SA98G, normBG)) - math.pow($txtY, map.get($SA98G, normTXT)));
@if $SAPC >= map.get($SA98G, loClip) {
$outputContrast: $SAPC - map.get($SA98G, loBoWoffset);
}
} @else {
$SAPC: map.get($SA98G, scaleWoB) * (math.pow($bgY, map.get($SA98G, revBG)) - math.pow($txtY, map.get($SA98G, revTXT)));
@if $SAPC <= -1 * map.get($SA98G, loClip) {
$outputContrast: $SAPC + map.get($SA98G, loWoBoffset);
}
}
@return $outputContrast * 100.0;
}
@function apcaReverse($contrast, $knownY, $knownType: 'bg') {
$unknownY: $knownY;
$knownExp: 0;
$unknownExp: 0;
$scale: map.get($SA98G, if($contrast > 0, scaleBoW, scaleWoB));
$offset: map.get($SA98G, if($contrast > 0, loBoWoffset, loWoBoffset));
$contrast: math.div($contrast * 0.01 + $offset, $scale);
@if $knownY <= map.get($SA98G, blkThrs) {
$knownY: $knownY + math.pow(map.get($SA98G, blkThrs) - $knownY, map.get($SA98G, blkClmp));
}
@if $knownType == 'bg' {
$knownExp: map.get($SA98G, if($contrast > 0, normBG, revBG));
$unknownExp: map.get($SA98G, if($contrast > 0, normTXT, revTXT));
$unknownY: math.pow(math.pow($knownY, $knownExp) - $contrast, math.div(1, $unknownExp));
} @else {
$knownExp: map.get($SA98G, if($contrast > 0, normTXT, revTXT));
$unknownExp: map.get($SA98G, if($contrast > 0, normBG, revBG));
$unknownY: math.pow($contrast + math.pow($knownY, $knownExp), math.div(1, $unknownExp));
}
@if '#{$unknownY}' == '#{math.sqrt(-1)}' {
@return false;
}
@if $unknownY > 1.06 or $unknownY < 0 {
@return false;
}
@if $unknownY <= map.get($SA98G, blkThrs) {
$unknownY: math.pow(
($unknownY + map.get($SA98G, mOffsetIn)) * map.get($SA98G, mFactor),
math.div(map.get($SA98G, mExpAdj), map.get($SA98G, blkClmp))
) * math.div(1, map.get($SA98G, mFactor)) - map.get($SA98G, mOffsetOut);
}
$unknownY: math.max(math.min($unknownY, 1), 0);
@return $unknownY;
}
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