ionic-framework/ionic/util/functions.scss

// Color Functions
// --------------------------------------------------

@function brightness($color-value) {
  @return (red($color-value) * 0.299 + green($color-value) * 0.587 + blue($color-value) * 0.114) / 255 * 100%;
}


@function inverse($color-value, $dark: black, $light: white) {
  $brightness: brightness($color-value);
  $red: red($color-value);
  $green: green($color-value);

  @if ($brightness > 79) {
    @return $dark;
  }

  @if ($green > 240) {
    @return $dark;
  }

  @if ($red > 220 and $green > 180) {
    @return $dark;
  }

  @return $light;
}


@function toolbar-button-inverse($color-value) {
  @return inverse($color-value, $dark: $toolbar-md-button-color, $light: white);
}


@function color-shade($color-value, $amount:8%) {
  $lightness: lightness($color-value);

  $shade: white;

  @if ($lightness > 50) {
    $shade: black;
  }

  @return mix($shade, $color-value, $amount);
}


// Copy Colors Map
// --------------------------------------------------

@function copy-colors($colors-map) {
  @return map-merge($colors-map, ());
}


// String Replace Function
// --------------------------------------------------

@function str-replace($string, $search, $replace: '') {
  $index: str-index($string, $search);

  @if $index {
    @return str-slice($string, 1, $index - 1) + $replace + str-replace(str-slice($string, $index + str-length($search)), $search, $replace);
  }

  @return $string;
}


// URL Encode Function
// --------------------------------------------------

@function url-encode($val) {
  @return str-replace($val, ' ', '%20');
}