bulma/sass/utilities/functions.sass

@function mergeColorMaps($bulma-colors, $custom-colors)
  // We return at least Bulma's hard-coded colors
  $merged-colors: $bulma-colors

  // We want a map as input
  @if type-of($custom-colors) == 'map'
    @each $name, $components in $custom-colors
      // The color name should be a string
      // and the components either a single color
      // or a colors list with at least one element
      @if type-of($name) == 'string' and (type-of($components) == 'list' or type-of($components) == 'color') and length($components) >= 1
        $color-base: null
        $color-invert: null
        $color-light: null
        $color-dark: null
        $value: null

        // The param can either be a single color
        // or a list of 2 colors
        @if type-of($components) == 'color'
          $color-base: $components
          $color-invert: findColorInvert($color-base)
          $color-light: findLightColor($color-base)
          $color-dark: findDarkColor($color-base)
        @else if type-of($components) == 'list'
          $color-base: nth($components, 1)
          // If Invert, Light and Dark are provided
          @if length($components) > 3
            $color-invert: nth($components, 2)
            $color-light: nth($components, 3)
            $color-dark: nth($components, 4)
            // If only Invert and Light are provided
          @else if length($components) > 2
            $color-invert: nth($components, 2)
            $color-light: nth($components, 3)
            $color-dark: findDarkColor($color-base)
            // If only Invert is provided
          @else
            $color-invert: nth($components, 2)
            $color-light: findLightColor($color-base)
            $color-dark: findDarkColor($color-base)

        $value: ($color-base, $color-invert, $color-light, $color-dark)

        // We only want to merge the map if the color base is an actual color
        @if type-of($color-base) == 'color'
          // We merge this colors elements as map with Bulma's colors map
          // (we can override them this way, no multiple definition for the same name)
          // $merged-colors: map_merge($merged-colors, ($name: ($color-base, $color-invert, $color-light, $color-dark)))
          $merged-colors: map_merge($merged-colors, ($name: $value))

  @return $merged-colors

@function powerNumber($number, $exp)
  $value: 1
  @if $exp > 0
    @for $i from 1 through $exp
      $value: $value * $number
  @else if $exp < 0
    @for $i from 1 through -$exp
      $value: $value / $number
  @return $value

@function colorLuminance($color)
  @if type-of($color) != 'color'
    @return 0.55
  $color-rgb: ('red': red($color),'green': green($color),'blue': blue($color))
  @each $name, $value in $color-rgb
    $adjusted: 0
    $value: $value / 255
    @if $value < 0.03928
      $value: $value / 12.92
    @else
      $value: ($value + .055) / 1.055
      $value: powerNumber($value, 2)
    $color-rgb: map-merge($color-rgb, ($name: $value))
  @return (map-get($color-rgb, 'red') * .2126) + (map-get($color-rgb, 'green') * .7152) + (map-get($color-rgb, 'blue') * .0722)

@function findColorInvert($color)
  @if (colorLuminance($color) > 0.55)
    @return rgba(#000, 0.7)
  @else
    @return #fff

@function findLightColor($color)
  @if type-of($color) == 'color'
    $l: 96%
    @if lightness($color) > 96%
      $l: lightness($color)
    @return change-color($color, $lightness: $l)
  @return $background

@function findDarkColor($color)
  @if type-of($color) == 'color'
    $base-l: 29%
    $luminance: colorLuminance($color)
    $luminance-delta: (0.53 - $luminance)
    $target-l: round($base-l + ($luminance-delta * 53))
    @return change-color($color, $lightness: max($base-l, $target-l))
  @return $text-strong

@function bulmaRgba($color, $alpha)
  @if type-of($color) != 'color'
    @return $color
  @return rgba($color, $alpha)

@function bulmaDarken($color, $amount)
  @if type-of($color) != 'color'
    @return $color
  @return darken($color, $amount)

@function bulmaLighten($color, $amount)
  @if type-of($color) != 'color'
    @return $color
  @return lighten($color, $amount)