Hyper-Station-13/tgui-next/packages/tgui/styles/functions.scss

/**
 * Copyright (c) 2018 Aleksej Komarov
 * SPDX-License-Identifier: GPL-2.0-or-later
 */

//  Type-casting
// --------------------------------------------------------

// Get a unit-less numeric value
@function num($value) {
  @if type-of($value) != number {
    @error 'Could not convert `#{$value}` - must be `type-of number`';
    @return null;
  }
  @if unit($value) == '%' {
    @return $value / 100%;
  }
  @return $value / ($value * 0 + 1);
}


//  Color
// --------------------------------------------------------

// Increases perceptual color lightness.
@function lighten($color, $percent) {
  $scaled: hsl(
    hue($color),
    saturation($color),
    lightness($color) * (1 + num($percent)));
  $mixed: mix(#ffffff, $color, 100% * num($percent));
  @return mix($scaled, $mixed, 75%);
}

// Returns the NTSC luminance of `$color` as a float (between 0 and 1).
// 1 is pure white, 0 is pure black.
@function luminance($color) {
  $colors: (
    'red': red($color),
    'green': green($color),
    'blue': blue($color)
  );

  @each $name, $value in $colors {
    $adjusted: 0;
    $value: $value / 255;
    @if $value < 0.03928 {
      $value: $value / 12.92;
    }
    @else {
      $value: ($value + .055) / 1.055;
      $value: math-pow($value, 2.4);
    }
    $colors: map-merge($colors, ($name: $value));
  }

  @return (map-get($colors, 'red') * .2126)
    + (map-get($colors, 'green') * .7152)
    + (map-get($colors, 'blue') * .0722);
}