Module: Sass::Script::Functions

Included in:
EvaluationContext
Defined in:
lib/sass/script/functions.rb

Overview

Methods in this module are accessible from the SassScript context. For example, you can write

$color = hsl(120deg, 100%, 50%)

and it will call #hsl.

The following functions are provided:

Note: These functions are described in more detail below.

RGB Functions

rgb($red, $green, $blue)
Converts an rgb(red, green, blue) triplet into a color.
rgba($red, $green, $blue, $alpha)
Converts an rgba(red, green, blue, alpha) quadruplet into a color.
rgba($color, $alpha)
Adds an alpha layer to any color value.
red($color)
Gets the red component of a color.
green($color)
Gets the green component of a color.
blue($color)
Gets the blue component of a color.
mix($color-1, $color-2, [$weight])
Mixes two colors together.

HSL Functions

hsl($hue, $saturation, $lightness)
Converts an hsl(hue, saturation, lightness) triplet into a color.
hsla($hue, $saturation, $lightness, $alpha)
Converts an hsla(hue, saturation, lightness, alpha) quadruplet into a color.
hue($color)
Gets the hue component of a color.
saturation($color)
Gets the saturation component of a color.
lightness($color)
Gets the lightness component of a color.
adjust-hue($color, $degrees)
Changes the hue of a color.
lighten($color, $amount)
Makes a color lighter.
darken($color, $amount)
Makes a color darker.
saturate($color, $amount)
Makes a color more saturated.
desaturate($color, $amount)
Makes a color less saturated.
grayscale($color)
Converts a color to grayscale.
complement($color)
Returns the complement of a color.
invert($color)
Returns the inverse of a color.

Opacity Functions

alpha($color) / opacity($color)
Gets the alpha component (opacity) of a color.
rgba($color, $alpha)
Add or change an alpha layer for any color value.
opacify($color, $amount) / fade-in($color, $amount)
Makes a color more opaque.
transparentize($color, $amount) / fade-out($color, $amount)
Makes a color more transparent.

Other Color Functions

adjust-color($color, [$red], [$green], [$blue], [$hue], [$saturation], [$lightness], [$alpha]
Increase or decrease any of the components of a color.
scale-color($color, [$red], [$green], [$blue], [$hue], [$saturation], [$lightness], [$alpha]
Fluidly scale one or more components of a color.
change-color($color, [$red], [$green], [$blue], [$hue], [$saturation], [$lightness], [$alpha]
Changes one or more properties of a color.

String Functions

unquote($string)
Removes the quotes from a string.
quote($string)
Adds quotes to a string.

Number Functions

percentage($value)
Converts a unitless number to a percentage.
round($value)
Rounds a number to the nearest whole number.
ceil($value)
Rounds a number up to the nearest whole number.
floor($value)
Rounds a number down to the nearest whole number.
abs($value)
Returns the absolute value of a number.

List Functions

length($list)
Returns the length of a list.
nth($list, $n)
Returns a specific item in a list.
join($list1, $list2, [$separator])
Joins together two lists into one.

Introspection Functions

type-of($value)
Returns the type of a value.
unit($number)
Returns the units associated with a number.
unitless($number)
Returns whether a number has units or not.
comparable($number-1, $number-2)
Returns whether two numbers can be added or compared.

Miscellaneous Functions

if($condition, $if-true, $if-false)
Returns one of two values, depending on whether or not a condition is true.

Adding Custom Functions

New Sass functions can be added by adding Ruby methods to this module. For example:

module Sass::Script::Functions
  def reverse(string)
    assert_type string, :String
    Sass::Script::String.new(string.value.reverse)
  end
  declare :reverse, :args => [:string]
end

Calling Functions.declare tells Sass the argument names for your function. If omitted, the function will still work, but will not be able to accept keyword arguments. Functions.declare can also allow your function to take arbitrary keyword arguments.

There are a few things to keep in mind when modifying this module. First of all, the arguments passed are Literal objects. Literal objects are also expected to be returned. This means that Ruby values must be unwrapped and wrapped.

Most Literal objects support the value accessor for getting their Ruby values. Color objects, though, must be accessed using rgb, red, green, or blue.

Second, making Ruby functions accessible from Sass introduces the temptation to do things like database access within stylesheets. This is generally a bad idea; since Sass files are by default only compiled once, dynamic code is not a great fit.

If you really, really need to compile Sass on each request, first make sure you have adequate caching set up. Then you can use Engine to render the code, using the options parameter to pass in data that can be accessed from your Sass functions.

Within one of the functions in this module, methods of EvaluationContext can be used.

Caveats

When creating new Literal objects within functions, be aware that it’s not safe to call #to_s (or other methods that use the string representation) on those objects without first setting the #options attribute.

Defined Under Namespace

Classes: EvaluationContext, Signature

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.declare(method_name, args, options = {})

Declare a Sass signature for a Ruby-defined function. This includes the names of the arguments, whether the function takes a variable number of arguments, and whether the function takes an arbitrary set of keyword arguments.

It’s not necessary to declare a signature for a function. However, without a signature it won’t support keyword arguments.

A single function can have multiple signatures declared as long as each one takes a different number of arguments. It’s also possible to declare multiple signatures that all take the same number of arguments, but none of them but the first will be used unless the user uses keyword arguments.

Examples:

declare :rgba, [:hex, :alpha]
declare :rgba, [:red, :green, :blue, :alpha]
declare :accepts_anything, [], :var_args => true, :var_kwargs => true
declare :some_func, [:foo, :bar, :baz], :var_kwargs => true

Parameters:

  • method_name (Symbol) —

    The name of the method whose signature is being declared.

  • args (Array<Symbol>) —

    The names of the arguments for the function signature.

  • options (Hash) (defaults to: {}) —

    a customizable set of options

Options Hash (options):

  • :var_args (Boolean) — default: false —

    Whether the function accepts a variable number of (unnamed) arguments in addition to the named arguments.

  • :var_kwargs (Boolean) — default: false —

    Whether the function accepts other keyword arguments in addition to those in :args. If this is true, the Ruby function will be passed a hash from strings to Literals as the last argument. In addition, if this is true and :var_args is not, Sass will ensure that the last argument passed is a hash.



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# File 'lib/sass/script/functions.rb', line 250

def self.declare(method_name, args, options = {})
  @signatures[method_name] ||= []
  @signatures[method_name] << Signature.new(
    args.map {|s| s.to_s},
    options[:var_args],
    options[:var_kwargs])
end

.signature(method_name, arg_arity, kwarg_arity) ⇒ {Symbol => Object}?

Determine the correct signature for the number of arguments passed in for a given function. If no signatures match, the first signature is returned for error messaging.

Parameters:

  • method_name (Symbol) —

    The name of the Ruby function to be called.

  • arg_arity (Number) —

    The number of unnamed arguments the function was passed.

  • kwarg_arity (Number) —

    The number of keyword arguments the function was passed.

Returns:

  • ({Symbol => Object}, nil) —

    The signature options for the matching signature, or nil if no signatures are declared for this function. See declare.



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# File 'lib/sass/script/functions.rb', line 269

def self.signature(method_name, arg_arity, kwarg_arity)
  return unless @signatures[method_name]
  @signatures[method_name].each do |signature|
    return signature if signature.args.size == arg_arity + kwarg_arity
    next unless signature.args.size < arg_arity + kwarg_arity

    # We have enough args.
    # Now we need to figure out which args are varargs
    # and if the signature allows them.
    t_arg_arity, t_kwarg_arity = arg_arity, kwarg_arity
    if signature.args.size > t_arg_arity
      # we transfer some kwargs arity to args arity
      # if it does not have enough args -- assuming the names will work out.
      t_kwarg_arity -= (signature.args.size - t_arg_arity)
      t_arg_arity = signature.args.size
    end

    if (  t_arg_arity == signature.args.size ||   t_arg_arity > signature.args.size && signature.var_args  ) &&
       (t_kwarg_arity == 0                   || t_kwarg_arity > 0                   && signature.var_kwargs)
      return signature
    end
  end
  @signatures[method_name].first
end

Instance Method Details

#abs(value) ⇒ Number

Finds the absolute value of a number.

Examples:

abs(10px) => 10px
abs(-10px) => 10px

Parameters:

  • value (Number) —

    The number

Returns:

  • (Number) —

    The absolute value

Raises:

  • (ArgumentError) —

    if value isn’t a number



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# File 'lib/sass/script/functions.rb', line 1185

def abs(value)
  numeric_transformation(value) {|n| n.abs}
end

#adjust_color(color, kwargs) ⇒ Color

Adjusts one or more properties of a color. This can change the red, green, blue, hue, saturation, value, and alpha properties. The properties are specified as keyword arguments, and are added to or subtracted from the color’s current value for that property.

$red, $green, and $blue properties should be between 0 and 255. $saturation and $lightness should be between 0% and 100%. $alpha should be between 0 and 1.

All properties are optional. You can’t specify both RGB properties ($red, $green, $blue) and HSL properties ($hue, $saturation, $value) at the same time.

Examples:

adjust-color(#102030, $blue: 5) => #102035
adjust-color(#102030, $red: -5, $blue: 5) => #0b2035
adjust-color(hsl(25, 100%, 80%), $lightness: -30%, $alpha: -0.4) => hsla(25, 100%, 50%, 0.6)

Parameters:

Returns:

Raises:

  • (ArgumentError) —

    if color is not a color, if any keyword argument is not a number, if any keyword argument is not in the legal range, if an unexpected keyword argument is given, or if both HSL and RGB properties are given.



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# File 'lib/sass/script/functions.rb', line 767

def adjust_color(color, kwargs)
  assert_type color, :Color
  with = Sass::Util.map_hash({
      "red" => [-255..255, ""],
      "green" => [-255..255, ""],
      "blue" => [-255..255, ""],
      "hue" => nil,
      "saturation" => [-100..100, "%"],
      "lightness" => [-100..100, "%"],
      "alpha" => [-1..1, ""]
    }) do |name, (range, units)|

    next unless val = kwargs.delete(name)
    assert_type val, :Number, name
    if range && !range.include?(val.value)
      raise ArgumentError.new("$#{name}: Amount #{val} must be between #{range.first}#{units} and #{range.last}#{units}")
    end
    adjusted = color.send(name) + val.value
    adjusted = [0, Sass::Util.restrict(adjusted, range)].max if range
    [name.to_sym, adjusted]
  end

  unless kwargs.empty?
    name, val = kwargs.to_a.first
    raise ArgumentError.new("Unknown argument $#{name} (#{val})")
  end

  color.with(with)
end

#adjust_hue(color, degrees) ⇒ Color

Changes the hue of a color while retaining the lightness and saturation. Takes a color and a number of degrees (usually between -360deg and 360deg), and returns a color with the hue rotated by that value.

Examples:

adjust-hue(hsl(120, 30%, 90%), 60deg) => hsl(180, 30%, 90%)
adjust-hue(hsl(120, 30%, 90%), 060deg) => hsl(60, 30%, 90%)
adjust-hue(#811, 45deg) => #886a11

Parameters:

Returns:

Raises:

  • (ArgumentError) —

    If color isn’t a color, or number isn’t a number



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# File 'lib/sass/script/functions.rb', line 729

def adjust_hue(color, degrees)
  assert_type color, :Color
  assert_type degrees, :Number
  color.with(:hue => color.hue + degrees.value)
end

#alpha(color) ⇒ Number

Returns the alpha component (opacity) of a color. This is 1 unless otherwise specified.

This function also supports the proprietary Microsoft alpha(opacity=20) syntax.

Parameters:

Returns:

Raises:

  • (ArgumentError) —

    If color isn’t a color

See Also:



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# File 'lib/sass/script/functions.rb', line 576

def alpha(*args)
  if args.all? do |a|
      a.is_a?(Sass::Script::String) && a.type == :identifier &&
        a.value =~ /^[a-zA-Z]+\s*=/
    end
    # Support the proprietary MS alpha() function
    return Sass::Script::String.new("alpha(#{args.map {|a| a.to_s}.join(", ")})")
  end

  opacity(*args)
end

#join(list, val, separator: auto)

Appends a single value onto the end of a list.

Unless the $separator argument is passed, if the list has only one item, the resulting list will be space-separated.

Examples:

append(10px 20px, 30px) => 10px 20px 30px
append((blue, red), green) => blue, red, green
append(10px 20px, 30px 40px) => 10px 20px (30px 40px)
join(10px, 20px, comma) => 10px, 20px
join((blue, red), green, space) => blue red green

Parameters:

  • list1 (Literal) —

    The first list to join

  • list2 (Literal) —

    The second list to join

  • separator (String) (defaults to: auto) —

    How the list separator (comma or space) should be determined. If this is comma or space, that is always the separator; if this is auto (the default), the separator is determined as explained above.



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# File 'lib/sass/script/functions.rb', line 1285

def append(list, val, separator = Sass::Script::String.new("auto"))
  assert_type separator, :String
  unless %w[auto space comma].include?(separator.value)
    raise ArgumentError.new("Separator name must be space, comma, or auto")
  end
  sep = list.separator if list.is_a?(Sass::Script::List)
  Sass::Script::List.new(
    list.to_a + [val],
    if separator.value == 'auto'
      sep || :space
    else
      separator.value.to_sym
    end)
end

#blue(color) ⇒ Number

Returns the blue component of a color.

Parameters:

Returns:

Raises:

  • (ArgumentError) —

    If color isn’t a color



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# File 'lib/sass/script/functions.rb', line 508

def blue(color)
  assert_type color, :Color
  Sass::Script::Number.new(color.blue)
end

#ceil(value) ⇒ Number

Rounds a number up to the nearest whole number.

Examples:

ciel(10.4px) => 11px
ciel(10.6px) => 11px

Parameters:

  • value (Number) —

    The number

Returns:

  • (Number) —

    The rounded number

Raises:

  • (ArgumentError) —

    if value isn’t a number



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# File 'lib/sass/script/functions.rb', line 1159

def ceil(value)
  numeric_transformation(value) {|n| n.ceil}
end

#change_color(color, kwargs) ⇒ Color

Changes one or more properties of a color. This can change the red, green, blue, hue, saturation, value, and alpha properties. The properties are specified as keyword arguments, and replace the color’s current value for that property.

$red, $green, and $blue properties should be between 0 and 255. $saturation and $lightness should be between 0% and 100%. $alpha should be between 0 and 1.

All properties are optional. You can’t specify both RGB properties ($red, $green, $blue) and HSL properties ($hue, $saturation, $value) at the same time.

Examples:

change-color(#102030, $blue: 5) => #102005
change-color(#102030, $red: 120, $blue: 5) => #782005
change-color(hsl(25, 100%, 80%), $lightness: 40%, $alpha: 0.8) => hsla(25, 100%, 40%, 0.8)

Parameters:

Returns:

Raises:

  • (ArgumentError) —

    if color is not a color, if any keyword argument is not a number, if any keyword argument is not in the legal range, if an unexpected keyword argument is given, or if both HSL and RGB properties are given.



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# File 'lib/sass/script/functions.rb', line 902

def change_color(color, kwargs)
  assert_type color, :Color
  with = Sass::Util.map_hash(%w[red green blue hue saturation lightness alpha]) do |name, max|
    next unless val = kwargs.delete(name)
    assert_type val, :Number, name
    [name.to_sym, val.value]
  end

  unless kwargs.empty?
    name, val = kwargs.to_a.first
    raise ArgumentError.new("Unknown argument $#{name} (#{val})")
  end

  color.with(with)
end

#comparable(number_1, number_2) ⇒ Bool

Returns true if two numbers are similar enough to be added, subtracted, or compared.

Examples:

comparable(2px, 1px) => true
comparable(100px, 3em) => false
comparable(10cm, 3mm) => true

Parameters:

Returns:

  • (Bool) —

    indicating if the numbers can be compared.

Raises:

  • (ArgumentError) —

    if number_1 or number_2 aren’t numbers



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# File 'lib/sass/script/functions.rb', line 1116

def comparable(number_1, number_2)
  assert_type number_1, :Number
  assert_type number_2, :Number
  Sass::Script::Bool.new(number_1.comparable_to?(number_2))
end

#complement(color) ⇒ Color

Returns the complement of a color. This is identical to adjust-hue(color, 180deg).

Parameters:

Returns:

Raises:

  • (ArgumentError) —

    if color isn’t a color

See Also:



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# File 'lib/sass/script/functions.rb', line 1004

def complement(color)
  adjust_hue color, Number.new(180)
end

#darken(color, amount) ⇒ Color

Makes a color darker. Takes a color and an amount between 0% and 100%, and returns a color with the lightness decreased by that value.

Examples:

darken(hsl(25, 100%, 80%), 30%) => hsl(25, 100%, 50%)
darken(#800, 20%) => #200

Parameters:

Returns:

Raises:

  • (ArgumentError) —

    If color isn’t a color, or number isn’t a number between 0% and 100%

See Also:



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# File 'lib/sass/script/functions.rb', line 676

def darken(color, amount)
  _adjust(color, amount, :lightness, 0..100, :-, "%")
end

#desaturate(color, amount) ⇒ Color

Makes a color less saturated. Takes a color and an amount between 0% and 100%, and returns a color with the saturation decreased by that value.

Examples:

desaturate(hsl(120, 30%, 90%), 20%) => hsl(120, 10%, 90%)
desaturate(#855, 20%) => #726b6b

Parameters:

Returns:

Raises:

  • (ArgumentError) —

    If color isn’t a color, or number isn’t a number between 0% and 100%

See Also:



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# File 'lib/sass/script/functions.rb', line 712

def desaturate(color, amount)
  _adjust(color, amount, :saturation, 0..100, :-, "%")
end

#floor(value) ⇒ Number

Rounds down to the nearest whole number.

Examples:

floor(10.4px) => 10px
floor(10.6px) => 10px

Parameters:

  • value (Number) —

    The number

Returns:

  • (Number) —

    The rounded number

Raises:

  • (ArgumentError) —

    if value isn’t a number



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# File 'lib/sass/script/functions.rb', line 1172

def floor(value)
  numeric_transformation(value) {|n| n.floor}
end

#grayscale(color) ⇒ Color

Converts a color to grayscale. This is identical to desaturate(color, 100%).

Parameters:

Returns:

Raises:

  • (ArgumentError) —

    if color isn’t a color

See Also:



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# File 'lib/sass/script/functions.rb', line 992

def grayscale(color)
  desaturate color, Number.new(100)
end

#green(color) ⇒ Number

Returns the green component of a color.

Parameters:

Returns:

Raises:

  • (ArgumentError) —

    If color isn’t a color



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# File 'lib/sass/script/functions.rb', line 497

def green(color)
  assert_type color, :Color
  Sass::Script::Number.new(color.green)
end

#hsl(hue, saturation, lightness) ⇒ Color

Creates a Color object from hue, saturation, and lightness. Uses the algorithm from the CSS3 spec.

Parameters:

  • hue (Number) —

    The hue of the color. Should be between 0 and 360 degrees, inclusive

  • saturation (Number) —

    The saturation of the color. Must be between 0% and 100%, inclusive

  • lightness (Number) —

    The lightness of the color. Must be between 0% and 100%, inclusive

Returns:

  • (Color) —

    The resulting color

Raises:

  • (ArgumentError) —

    if saturation or lightness are out of bounds

See Also:



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# File 'lib/sass/script/functions.rb', line 440

def hsl(hue, saturation, lightness)
  hsla(hue, saturation, lightness, Number.new(1))
end

#hsla(hue, saturation, lightness, alpha) ⇒ Color

Creates a Color object from hue, saturation, and lightness, as well as an alpha channel indicating opacity. Uses the algorithm from the CSS3 spec.

Parameters:

  • hue (Number) —

    The hue of the color. Should be between 0 and 360 degrees, inclusive

  • saturation (Number) —

    The saturation of the color. Must be between 0% and 100%, inclusive

  • lightness (Number) —

    The lightness of the color. Must be between 0% and 100%, inclusive

  • alpha (Number) —

    The opacity of the color. Must be between 0 and 1, inclusive

Returns:

  • (Color) —

    The resulting color

Raises:

  • (ArgumentError) —

    if saturation, lightness, or alpha are out of bounds

See Also:



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# File 'lib/sass/script/functions.rb', line 460

def hsla(hue, saturation, lightness, alpha)
  assert_type hue, :Number
  assert_type saturation, :Number
  assert_type lightness, :Number
  assert_type alpha, :Number

  unless (0..1).include?(alpha.value)
    raise ArgumentError.new("Alpha channel #{alpha.value} must be between 0 and 1")
  end

  original_s = saturation
  original_l = lightness
  # This algorithm is from http://www.w3.org/TR/css3-color#hsl-color
  h, s, l = [hue, saturation, lightness].map { |a| a.value }
  raise ArgumentError.new("Saturation #{s} must be between 0% and 100%") unless (0..100).include?(s)
  raise ArgumentError.new("Lightness #{l} must be between 0% and 100%") unless (0..100).include?(l)

  Color.new(:hue => h, :saturation => s, :lightness => l, :alpha => alpha.value)
end

#hue(color) ⇒ Number

Returns the hue component of a color.

See the CSS3 HSL specification.

Calculated from RGB where necessary via this algorithm.

Parameters:

Returns:

  • (Number) —

    between 0deg and 360deg

Raises:

  • (ArgumentError) —

    if color isn’t a color

See Also:



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# File 'lib/sass/script/functions.rb', line 524

def hue(color)
  assert_type color, :Color
  Sass::Script::Number.new(color.hue, ["deg"])
end

#if(condition, if_true, if_false)

Returns one of two values based on the truth value of the first argument.

Examples:

if(true, 1px, 2px) => 1px
if(false, 1px, 2px) => 2px

Parameters:

  • condition (Bool) —

    Whether the first or second value will be returned.

  • if_true (Literal) —

    The value that will be returned if $condition is true.

  • if_false (Literal) —

    The value that will be returned if $condition is false.



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# File 'lib/sass/script/functions.rb', line 1353

def if(condition, if_true, if_false)
  if condition.to_bool
    if_true
  else
    if_false
  end
end

#index(list, value)

Returns the position of the given value within the given list. If not found, returns false.

Examples:

index(1px solid red, solid) => 2
index(1px solid red, dashed) => false


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# File 'lib/sass/script/functions.rb', line 1334

def index(list, value)
  assert_type list, :List
  index = list.value.index {|e| e.eq(value).to_bool }
  if index
    Number.new(index + 1)
  else
    Bool.new(false)
  end
end

#invert(color) ⇒ Color

Returns the inverse (negative) of a color. The red, green, and blue values are inverted, while the opacity is left alone.

Parameters:

Returns:

Raises:

  • (ArgumentError) —

    if color isn’t a color



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# File 'lib/sass/script/functions.rb', line 1015

def invert(color)
  assert_type color, :Color
  color.with(
    :red => (255 - color.red),
    :green => (255 - color.green),
    :blue => (255 - color.blue))
end

#join(list1, list2, separator: auto)

Joins together two lists into a new list.

Unless the $separator argument is passed, if one list is comma-separated and one is space-separated, the first parameter’s separator is used for the resulting list. If the lists have only one item each, spaces are used for the resulting list.

Examples:

join(10px 20px, 30px 40px) => 10px 20px 30px 40px
join((blue, red), (#abc, #def)) => blue, red, #abc, #def
join(10px, 20px) => 10px 20px
join(10px, 20px, comma) => 10px, 20px
join((blue, red), (#abc, #def), space) => blue red #abc #def

Parameters:

  • list1 (Literal) —

    The first list to join

  • list2 (Literal) —

    The second list to join

  • separator (String) (defaults to: auto) —

    How the list separator (comma or space) should be determined. If this is comma or space, that is always the separator; if this is auto (the default), the separator is determined as explained above.



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# File 'lib/sass/script/functions.rb', line 1249

def join(list1, list2, separator = Sass::Script::String.new("auto"))
  assert_type separator, :String
  unless %w[auto space comma].include?(separator.value)
    raise ArgumentError.new("Separator name must be space, comma, or auto")
  end
  sep1 = list1.separator if list1.is_a?(Sass::Script::List) && !list1.value.empty?
  sep2 = list2.separator if list2.is_a?(Sass::Script::List) && !list2.value.empty?
  Sass::Script::List.new(
    list1.to_a + list2.to_a,
    if separator.value == 'auto'
      sep1 || sep2 || :space
    else
      separator.value.to_sym
    end)
end

#length(list) ⇒ Number

Return the length of a list.

Examples:

length(10px) => 1
length(10px 20px 30px) => 3

Parameters:

Returns:



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# File 'lib/sass/script/functions.rb', line 1197

def length(list)
  Sass::Script::Number.new(list.to_a.size)
end

#lighten(color, amount) ⇒ Color

Makes a color lighter. Takes a color and an amount between 0% and 100%, and returns a color with the lightness increased by that value.

Examples:

lighten(hsl(0, 0%, 0%), 30%) => hsl(0, 0, 30)
lighten(#800, 20%) => #e00

Parameters:

Returns:

Raises:

  • (ArgumentError) —

    If color isn’t a color, or number isn’t a number between 0% and 100%

See Also:



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# File 'lib/sass/script/functions.rb', line 658

def lighten(color, amount)
  _adjust(color, amount, :lightness, 0..100, :+, "%")
end

#lightness(color) ⇒ Number

Returns the hue component of a color.

See the CSS3 HSL specification.

Calculated from RGB where necessary via this algorithm.

Parameters:

Returns:

  • (Number) —

    between 0% and 100%

Raises:

  • (ArgumentError) —

    if color isn’t a color

See Also:



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# File 'lib/sass/script/functions.rb', line 558

def lightness(color)
  assert_type color, :Color
  Sass::Script::Number.new(color.lightness, ["%"])
end

#mix(color1, color2, weight: 50%) ⇒ Color

Mixes together two colors. Specifically, takes the average of each of the RGB components, optionally weighted by the given percentage. The opacity of the colors is also considered when weighting the components.

The weight specifies the amount of the first color that should be included in the returned color. The default, 50%, means that half the first color and half the second color should be used. 25% means that a quarter of the first color and three quarters of the second color should be used.

Examples:

mix(#f00, #00f) => #7f007f
mix(#f00, #00f, 25%) => #3f00bf
mix(rgba(255, 0, 0, 0.5), #00f) => rgba(63, 0, 191, 0.75)

Parameters:

  • color1 (Color)
  • color2 (Color)
  • weight (Number) (defaults to: 50%) —

    between 0% and 100%

Returns:

Raises:

  • (ArgumentError) —

    if color1 or color2 aren’t colors, or weight isn’t a number between 0% and 100%



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# File 'lib/sass/script/functions.rb', line 942

def mix(color1, color2, weight = Number.new(50))
  assert_type color1, :Color
  assert_type color2, :Color
  assert_type weight, :Number

  unless (0..100).include?(weight.value)
    raise ArgumentError.new("Weight #{weight} must be between 0% and 100%")
  end

  # This algorithm factors in both the user-provided weight
  # and the difference between the alpha values of the two colors
  # to decide how to perform the weighted average of the two RGB values.
  #
  # It works by first normalizing both parameters to be within [-1, 1],
  # where 1 indicates "only use color1", -1 indicates "only use color 0",
  # and all values in between indicated a proportionately weighted average.
  #
  # Once we have the normalized variables w and a,
  # we apply the formula (w + a)/(1 + w*a)
  # to get the combined weight (in [-1, 1]) of color1.
  # This formula has two especially nice properties:
  #
  #   * When either w or a are -1 or 1, the combined weight is also that number
  #     (cases where w * a == -1 are undefined, and handled as a special case).
  #
  #   * When a is 0, the combined weight is w, and vice versa
  #
  # Finally, the weight of color1 is renormalized to be within [0, 1]
  # and the weight of color2 is given by 1 minus the weight of color1.
  p = weight.value/100.0
  w = p*2 - 1
  a = color1.alpha - color2.alpha

  w1 = (((w * a == -1) ? w : (w + a)/(1 + w*a)) + 1)/2.0
  w2 = 1 - w1

  rgb = color1.rgb.zip(color2.rgb).map {|v1, v2| v1*w1 + v2*w2}
  alpha = color1.alpha*p + color2.alpha*(1-p)
  Color.new(rgb + [alpha])
end

#nth(list, n) ⇒ Literal

Gets the nth item in a list.

Note that unlike some languages, the first item in a Sass list is number 1, the second number 2, and so forth.

Examples:

nth(10px 20px 30px, 1) => 10px
nth((Helvetica, Arial, sans-serif), 3) => sans-serif

Parameters:

  • list (Literal) —

    The list

  • n (Number) —

    The index into the list

Returns:

  • (Literal) —

    The nth item in the list

Raises:

  • (ArgumentError) —

    If n isn’t an integer between 1 and the list’s length.



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# File 'lib/sass/script/functions.rb', line 1214

def nth(list, n)
  assert_type n, :Number
  if !n.int?
    raise ArgumentError.new("List index #{n} must be an integer")
  elsif n.to_i < 1
    raise ArgumentError.new("List index #{n} must be greater than or equal to 1")
  elsif list.to_a.size == 0
    raise ArgumentError.new("List index is #{n} but list has no items")
  elsif n.to_i > (size = list.to_a.size)
    raise ArgumentError.new("List index is #{n} but list is only #{size} item#{'s' if size != 1} long")
  end

  list.to_a[n.to_i - 1]
end

#opacify(color, amount) ⇒ Color Also known as: fade_in

Makes a color more opaque. Takes a color and an amount between 0 and 1, and returns a color with the opacity increased by that value.

Examples:

opacify(rgba(0, 0, 0, 0.5), 0.1) => rgba(0, 0, 0, 0.6)
opacify(rgba(0, 0, 17, 0.8), 0.2) => #001

Parameters:

Returns:

Raises:

  • (ArgumentError) —

    If color isn’t a color, or number isn’t a number between 0 and 1

See Also:



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# File 'lib/sass/script/functions.rb', line 616

def opacify(color, amount)
  _adjust(color, amount, :alpha, 0..1, :+)
end

#opacity(color) ⇒ Number

Returns the alpha component (opacity) of a color. This is 1 unless otherwise specified.

Parameters:

Returns:

Raises:

  • (ArgumentError) —

    If color isn’t a color

See Also:



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# File 'lib/sass/script/functions.rb', line 597

def opacity(color)
  assert_type color, :Color
  Sass::Script::Number.new(color.alpha)
end

#percentage(value) ⇒ Number

Converts a decimal number to a percentage.

Examples:

percentage(100px / 50px) => 200%

Parameters:

  • value (Number) —

    The decimal number to convert to a percentage

Returns:

Raises:

  • (ArgumentError) —

    If value isn’t a unitless number



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# File 'lib/sass/script/functions.rb', line 1130

def percentage(value)
  unless value.is_a?(Sass::Script::Number) && value.unitless?
    raise ArgumentError.new("#{value.inspect} is not a unitless number")
  end
  Sass::Script::Number.new(value.value * 100, ['%'])
end

#quote(string) ⇒ String

Add quotes to a string if the string isn’t quoted, or returns the same string if it is.

Examples:

quote("foo") => "foo"
quote(foo) => "foo"

Parameters:

Returns:

Raises:

  • (ArgumentError) —

    if string isn’t a string

See Also:



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# File 'lib/sass/script/functions.rb', line 1052

def quote(string)
  assert_type string, :String
  Sass::Script::String.new(string.value, :string)
end

#red(color) ⇒ Number

Returns the red component of a color.

Parameters:

Returns:

Raises:

  • (ArgumentError) —

    If color isn’t a color



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# File 'lib/sass/script/functions.rb', line 486

def red(color)
  assert_type color, :Color
  Sass::Script::Number.new(color.red)
end

#rgb(red, green, blue) ⇒ Color

Creates a Color object from red, green, and blue values.

Parameters:

  • red (Number) —

    A number between 0 and 255 inclusive, or between 0% and 100% inclusive

  • green (Number) —

    A number between 0 and 255 inclusive, or between 0% and 100% inclusive

  • blue (Number) —

    A number between 0 and 255 inclusive, or between 0% and 100% inclusive

Returns:

See Also:



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# File 'lib/sass/script/functions.rb', line 361

def rgb(red, green, blue)
  assert_type red, :Number
  assert_type green, :Number
  assert_type blue, :Number

  Color.new([red, green, blue].map do |c|
      v = c.value
      if c.numerator_units == ["%"] && c.denominator_units.empty?
        next v * 255 / 100.0 if (0..100).include?(v)
        raise ArgumentError.new("Color value #{c} must be between 0% and 100% inclusive")
      else
        next v if (0..255).include?(v)
        raise ArgumentError.new("Color value #{v} must be between 0 and 255 inclusive")
      end
    end)
end

#rgba(red, green, blue, alpha) ⇒ Color #rgba(color, alpha) ⇒ Color

Overloads:

  • #rgba(red, green, blue, alpha) ⇒ Color

    Creates a Color object from red, green, and blue values, as well as an alpha channel indicating opacity.

    Parameters:

    • red (Number) —

      A number between 0 and 255 inclusive

    • green (Number) —

      A number between 0 and 255 inclusive

    • blue (Number) —

      A number between 0 and 255 inclusive

    • alpha (Number) —

      A number between 0 and 1

    Returns:

  • #rgba(color, alpha) ⇒ Color

    Sets the opacity of a color.

    Examples:

    rgba(#102030, 0.5) => rgba(16, 32, 48, 0.5)
rgba(blue, 0.2)    => rgba(0, 0, 255, 0.2)

    Parameters:

    • color (Color)
    • alpha (Number) —

      A number between 0 and 1

    Returns:

See Also:



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# File 'lib/sass/script/functions.rb', line 405

def rgba(*args)
  case args.size
  when 2
    color, alpha = args

    assert_type color, :Color
    assert_type alpha, :Number

    unless (0..1).include?(alpha.value)
      raise ArgumentError.new("Alpha channel #{alpha.value} must be between 0 and 1 inclusive")
    end

    color.with(:alpha => alpha.value)
  when 4
    red, green, blue, alpha = args
    rgba(rgb(red, green, blue), alpha)
  else
    raise ArgumentError.new("wrong number of arguments (#{args.size} for 4)")
  end
end

#round(value) ⇒ Number

Rounds a number to the nearest whole number.

Examples:

round(10.4px) => 10px
round(10.6px) => 11px

Parameters:

  • value (Number) —

    The number

Returns:

  • (Number) —

    The rounded number

Raises:

  • (ArgumentError) —

    if value isn’t a number



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# File 'lib/sass/script/functions.rb', line 1146

def round(value)
  numeric_transformation(value) {|n| n.round}
end

#saturate(color, amount) ⇒ Color

Makes a color more saturated. Takes a color and an amount between 0% and 100%, and returns a color with the saturation increased by that value.

Examples:

saturate(hsl(120, 30%, 90%), 20%) => hsl(120, 50%, 90%)
saturate(#855, 20%) => #9e3f3f

Parameters:

Returns:

Raises:

  • (ArgumentError) —

    If color isn’t a color, or number isn’t a number between 0% and 100%

See Also:



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# File 'lib/sass/script/functions.rb', line 694

def saturate(color, amount)
  _adjust(color, amount, :saturation, 0..100, :+, "%")
end

#saturation(color) ⇒ Number

Returns the saturation component of a color.

See the CSS3 HSL specification.

Calculated from RGB where necessary via this algorithm.

Parameters:

Returns:

  • (Number) —

    between 0% and 100%

Raises:

  • (ArgumentError) —

    if color isn’t a color

See Also:



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# File 'lib/sass/script/functions.rb', line 541

def saturation(color)
  assert_type color, :Color
  Sass::Script::Number.new(color.saturation, ["%"])
end

#scale_color(color, kwargs) ⇒ Color

Scales one or more properties of a color by a percentage value. Unlike adjust-color, which changes a color’s properties by fixed amounts, scale-color fluidly changes them based on how high or low they already are. That means that lightening an already-light color with scale-color won’t change the lightness much, but lightening a dark color by the same amount will change it more dramatically. This has the benefit of making scale-color($color, ...) have a similar effect regardless of what $color is.

For example, the lightness of a color can be anywhere between 0 and 100. If scale-color($color, $lightness: 40%) is called, the resulting color’s lightness will be 40% of the way between its original lightness and 100. If scale-color($color, $lightness: -40%) is called instead, the lightness will be 40% of the way between the original and 0.

This can change the red, green, blue, saturation, value, and alpha properties. The properties are specified as keyword arguments. All arguments should be percentages between 0% and 100%.

All properties are optional. You can’t specify both RGB properties ($red, $green, $blue) and HSL properties ($saturation, $value) at the same time.

Examples:

scale-color(hsl(120, 70, 80), $lightness: 50%) => hsl(120, 70, 90)
scale-color(rgb(200, 150, 170), $green: -40%, $blue: 70%) => rgb(200, 90, 229)
scale-color(hsl(200, 70, 80), $saturation: -90%, $alpha: -30%) => hsla(200, 7, 80, 0.7)

Parameters:

Returns:

Raises:

  • (ArgumentError) —

    if color is not a color, if any keyword argument is not a percentage between 0% and 100%, if an unexpected keyword argument is given, or if both HSL and RGB properties are given.



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# File 'lib/sass/script/functions.rb', line 837

def scale_color(color, kwargs)
  assert_type color, :Color
  with = Sass::Util.map_hash({
      "red" => 255,
      "green" => 255,
      "blue" => 255,
      "saturation" => 100,
      "lightness" => 100,
      "alpha" => 1
    }) do |name, max|

    next unless val = kwargs.delete(name)
    assert_type val, :Number, name
    if !(val.numerator_units == ['%'] && val.denominator_units.empty?)
      raise ArgumentError.new("$#{name}: Amount #{val} must be a % (e.g. #{val.value}%)")
    elsif !(-100..100).include?(val.value)
      raise ArgumentError.new("$#{name}: Amount #{val} must be between -100% and 100%")
    end

    current = color.send(name)
    scale = val.value/100.0
    diff = scale > 0 ? max - current : current
    [name.to_sym, current + diff*scale]
  end

  unless kwargs.empty?
    name, val = kwargs.to_a.first
    raise ArgumentError.new("Unknown argument $#{name} (#{val})")
  end

  color.with(with)
end

#transparentize(color, amount) ⇒ Color Also known as: fade_out

Makes a color more transparent. Takes a color and an amount between 0 and 1, and returns a color with the opacity decreased by that value.

Examples:

transparentize(rgba(0, 0, 0, 0.5), 0.1) => rgba(0, 0, 0, 0.4)
transparentize(rgba(0, 0, 0, 0.8), 0.2) => rgba(0, 0, 0, 0.6)

Parameters:

Returns:

Raises:

  • (ArgumentError) —

    If color isn’t a color, or number isn’t a number between 0 and 1

See Also:



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# File 'lib/sass/script/functions.rb', line 637

def transparentize(color, amount)
  _adjust(color, amount, :alpha, 0..1, :-)
end

#type_of(value) ⇒ String

Inspects the type of the argument, returning it as an unquoted string.

Examples:

type-of(100px)  => number
type-of(asdf)   => string
type-of("asdf") => string
type-of(true)   => bool
type-of(#fff)   => color
type-of(blue)   => color

Parameters:

  • value (Literal) —

    The object to inspect

Returns:

  • (String) —

    The unquoted string name of the literal’s type



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# File 'lib/sass/script/functions.rb', line 1069

def type_of(value)
  Sass::Script::String.new(value.class.name.gsub(/Sass::Script::/,'').downcase)
end

#unit(number) ⇒ String

Inspects the unit of the number, returning it as a quoted string. Complex units are sorted in alphabetical order by numerator and denominator.

Examples:

unit(100) => ""
unit(100px) => "px"
unit(3em) => "em"
unit(10px * 5em) => "em*px"
unit(10px * 5em / 30cm / 1rem) => "em*px/cm*rem"

Parameters:

  • number (Literal) —

    The number to inspect

Returns:

  • (String) —

    The unit(s) of the number

Raises:

  • (ArgumentError) —

    if number isn’t a number



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# File 'lib/sass/script/functions.rb', line 1086

def unit(number)
  assert_type number, :Number
  Sass::Script::String.new(number.unit_str, :string)
end

#unitless(number) ⇒ Bool

Inspects the unit of the number, returning a boolean indicating if it is unitless.

Examples:

unitless(100) => true
unitless(100px) => false

Parameters:

  • number (Literal) —

    The number to inspect

Returns:

  • (Bool) —

    Whether or not the number is unitless

Raises:

  • (ArgumentError) —

    if number isn’t a number



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# File 'lib/sass/script/functions.rb', line 1100

def unitless(number)
  assert_type number, :Number
  Sass::Script::Bool.new(number.unitless?)
end

#unquote(string) ⇒ String

Removes quotes from a string if the string is quoted, or returns the same string if it’s not.

Examples:

unquote("foo") => foo
unquote(foo) => foo

Parameters:

Returns:

Raises:

  • (ArgumentError) —

    if string isn’t a string

See Also:



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# File 'lib/sass/script/functions.rb', line 1033

def unquote(string)
  if string.is_a?(Sass::Script::String)
    Sass::Script::String.new(string.value, :identifier)
  else
    string
  end
end

#zip(*lists)

Combines several lists into a single comma separated list space separated lists.

The length of the resulting list is the length of the shortest list.

Examples:

zip(1px 1px 3px, solid dashed solid, red green blue)
=> 1px solid red, 1px dashed green, 3px solid blue


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# File 'lib/sass/script/functions.rb', line 1311

def zip(*lists)
  length = nil
  values = []
  lists.each do |list|
    assert_type list, :List
    values << list.value.dup
    length = length.nil? ? list.value.length : [length, list.value.length].min
  end
  values.each do |value|
    value.slice!(length)
  end
  new_list_value = values.first.zip(*values[1..-1])
  List.new(new_list_value.map{|list| List.new(list, :space)}, :comma)
end