Module | Sass::Script::Functions |
In: |
lib/sass/script/functions.rb
|
Methods in this module are accessible from the SassScript context. For example, you can write
$color = hsl(120deg, 100%, 50%)
and it will call {Sass::Script::Functions#hsl}.
The following functions are provided:
*Note: These functions are described in more detail below.*
## RGB Functions
\{rgb rgb($red, $green, $blue)} : Converts an `rgb(red, green, blue)` triplet into a color.
\{rgba rgba($red, $green, $blue, $alpha)} : Converts an `rgba(red, green, blue, alpha)` quadruplet into a color.
\{rgba rgba($color, $alpha)} : Adds an alpha layer to any color value.
\{red red($color)} : Gets the red component of a color.
\{green green($color)} : Gets the green component of a color.
\{blue blue($color)} : Gets the blue component of a color.
\{mix mix($color-1, $color-2, \[$weight\])} : Mixes two colors together.
## HSL Functions
\{hsl hsl($hue, $saturation, $lightness)} : Converts an `hsl(hue, saturation, lightness)` triplet into a color.
\{hsla hsla($hue, $saturation, $lightness, $alpha)} : Converts an `hsla(hue, saturation, lightness, alpha)` quadruplet into a color.
\{hue hue($color)} : Gets the hue component of a color.
\{saturation saturation($color)} : Gets the saturation component of a color.
\{lightness lightness($color)} : Gets the lightness component of a color.
\{adjust_hue adjust-hue($color, $degrees)} : Changes the hue of a color.
\{lighten lighten($color, $amount)} : Makes a color lighter.
\{darken darken($color, $amount)} : Makes a color darker.
\{saturate saturate($color, $amount)} : Makes a color more saturated.
\{desaturate desaturate($color, $amount)} : Makes a color less saturated.
\{grayscale grayscale($color)} : Converts a color to grayscale.
\{complement complement($color)} : Returns the complement of a color.
\{invert invert($color)} : Returns the inverse of a color.
## Opacity Functions
\{alpha alpha($color)} / \{opacity opacity($color)} : Gets the alpha component (opacity) of a color.
\{rgba rgba($color, $alpha)} : Add or change an alpha layer for any color value.
\{opacify opacify($color, $amount)} / \{fade_in fade-in($color, $amount)} : Makes a color more opaque.
\{transparentize transparentize($color, $amount)} / \{fade_out fade-out($color, $amount)} : Makes a color more transparent.
\{adjust_color adjust-color($color, \[$red\], \[$green\], \[$blue\], \[$hue\], \[$saturation\], \[$lightness\], \[$alpha\]} : Increase or decrease any of the components of a color.
\{scale_color scale-color($color, \[$red\], \[$green\], \[$blue\], \[$saturation\], \[$lightness\], \[$alpha\]} : Fluidly scale one or more components of a color.
\{change_color change-color($color, \[$red\], \[$green\], \[$blue\], \[$hue\], \[$saturation\], \[$lightness\], \[$alpha\]} : Changes one or more properties of a color.
\{unquote unquote($string)} : Removes the quotes from a string.
\{quote quote($string)} : Adds quotes to a string.
\{percentage percentage($value)} : Converts a unitless number to a percentage.
\{round round($value)} : Rounds a number to the nearest whole number.
\{ceil ceil($value)} : Rounds a number up to the nearest whole number.
\{floor floor($value)} : Rounds a number down to the nearest whole number.
\{abs abs($value)} : Returns the absolute value of a number.
## List Functions {list-functions}
\{length length($list)} : Returns the length of a list.
\{nth nth($list, $n)} : Returns a specific item in a list.
\{join join($list1, $list2, \[$separator\])} : Joins together two lists into one.
## Introspection Functions
\{type_of type-of($value)} : Returns the type of a value.
\{unit unit($number)} : Returns the units associated with a number.
\{unitless unitless($number)} : Returns whether a number has units or not.
\{comparable comparable($number-1, $number-2)} : Returns whether two numbers can be added or compared.
## Miscellaneous Functions
\{if if($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 {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. {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 {Sass::Script::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 {Sass::Script::Literal#value value} accessor for getting their Ruby values. Color objects, though, must be accessed using {Sass::Script::Color#rgb rgb}, {Sass::Script::Color#red red}, {Sass::Script::Color#blue green}, or {Sass::Script::Color#blue 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 {Sass::Engine} to render the code, using the {file:SASS_REFERENCE.md#custom-option `options` parameter} to pass in data that {EvaluationContext#options 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 {Literal#to_s to_s} (or other methods that use the string representation) on those objects without first setting {Node#options= the options attribute}.
Signature | = | Struct.new(:args, :var_args, :var_kwargs) |
A class representing a Sass function signature.
@attr args [Array<Symbol>] The names of the arguments to the function. @attr var_args [Boolean] Whether the function takes a variable number of arguments. @attr var_kwargs [Boolean] Whether the function takes an arbitrary set of keyword arguments. |
public_method_defined? | -> | callable? |
Returns whether user function with a given name exists.
@param function_name [String] @return [Boolean] |
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.
@param method_name [Symbol] The name of the method
whose signature is being declared.
@param args [Array<Symbol>] The names of the arguments for the function signature. @option options :var_args [Boolean] (false)
Whether the function accepts a variable number of (unnamed) arguments in addition to the named arguments.
@option options :var_kwargs [Boolean] (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 {Sass::Script::Literal}s 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.
@example
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
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.
@param method_name [Symbol] The name of the Ruby function to be called. @param arg_arity [Number] The number of unnamed arguments the function was passed. @param kwarg_arity [Number] The number of keyword arguments the function was passed.
@return [{Symbol => Object}, nil]
The signature options for the matching signature, or nil if no signatures are declared for this function. See {declare}.
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.
@example
adjust-color(#102030, $blue: 5) => #102035 adjust-color(#102030, $red: -5, $blue: 5) => #0b2035 adjust-color(hsl(25, 100%, 80%), $lightness: -30%, $alpha: -0.4) => hsla(25, 100%, 50%, 0.6)
@param color [Color] @param red [Number] @param green [Number] @param blue [Number] @param hue [Number] @param saturation [Number] @param lightness [Number] @param alpha [Number] @return [Color] @raise [ArgumentError] if `color` is not a color,
if any keyword argument is not a number, if any keyword argument is not in the legal range, if an unexpected keyword argument is given, or if both HSL and RGB properties are given.
Changes the hue of a color while retaining the lightness and saturation. Takes a color and a number of degrees (usually between -360deg and 360deg), and returns a color with the hue rotated by that value.
@example
adjust-hue(hsl(120, 30%, 90%), 60deg) => hsl(180, 30%, 90%) adjust-hue(hsl(120, 30%, 90%), 060deg) => hsl(60, 30%, 90%) adjust-hue(#811, 45deg) => #886a11
@param color [Color] @param amount [Number] @return [Color] @raise [ArgumentError] If `color` isn‘t a color, or `number` isn‘t a number
Returns the alpha component (opacity) of a color. This is 1 unless otherwise specified.
This function also supports the proprietary Microsoft `alpha(opacity=20)` syntax.
@overload def alpha(color) @param color [Color] @return [Number] @see opacify @see transparentize @raise [ArgumentError] If `color` isn‘t a color
Appends a single value onto the end of a list.
Unless the `$separator` argument is passed, if the list has only one item, the resulting list will be space-separated.
@example
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
@overload join(list, val, separator: auto)
@param list1 [Literal] The first list to join @param list2 [Literal] The second list to join @param separator [String] 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.
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.
@example
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)
@param color [Color] @param red [Number] @param green [Number] @param blue [Number] @param hue [Number] @param saturation [Number] @param lightness [Number] @param alpha [Number] @return [Color] @raise [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.
Returns true if two numbers are similar enough to be added, subtracted, or compared.
@example
comparable(2px, 1px) => true comparable(100px, 3em) => false comparable(10cm, 3mm) => true
@param number_1 [Number] @param number_2 [Number] @return [Bool] indicating if the numbers can be compared. @raise [ArgumentError] if `number_1` or `number_2` aren‘t numbers
Returns the complement of a color. This is identical to `adjust-hue(color, 180deg)`.
@param color [Color] @return [Color] @raise [ArgumentError] if `color` isn‘t a color @see adjust_hue adjust-hue
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.
@example
darken(hsl(25, 100%, 80%), 30%) => hsl(25, 100%, 50%) darken(#800, 20%) => #200
@param color [Color] @param amount [Number] @return [Color] @see lighten @raise [ArgumentError] If `color` isn‘t a color,
or `number` isn't a number between 0% and 100%
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.
@example
desaturate(hsl(120, 30%, 90%), 20%) => hsl(120, 10%, 90%) desaturate(#855, 20%) => #726b6b
@param color [Color] @param amount [Number] @return [Color] @see saturate @raise [ArgumentError] If `color` isn‘t a color,
or `number` isn't a number between 0% and 100%
Converts a color to grayscale. This is identical to `desaturate(color, 100%)`.
@param color [Color] @return [Color] @raise [ArgumentError] if `color` isn‘t a color @see desaturate
Creates a {Color} object from hue, saturation, and lightness. Uses the algorithm from the [CSS3 spec](www.w3.org/TR/css3-color/#hsl-color).
@param hue [Number] The hue of the color.
Should be between 0 and 360 degrees, inclusive
@param saturation [Number] The saturation of the color.
Must be between `0%` and `100%`, inclusive
@param lightness [Number] The lightness of the color.
Must be between `0%` and `100%`, inclusive
@return [Color] The resulting color @see hsla @raise [ArgumentError] if `saturation` or `lightness` are out of bounds
Creates a {Color} object from hue, saturation, and lightness, as well as an alpha channel indicating opacity. Uses the algorithm from the [CSS3 spec](www.w3.org/TR/css3-color/#hsl-color).
@param hue [Number] The hue of the color.
Should be between 0 and 360 degrees, inclusive
@param saturation [Number] The saturation of the color.
Must be between `0%` and `100%`, inclusive
@param lightness [Number] The lightness of the color.
Must be between `0%` and `100%`, inclusive
@param alpha [Number] The opacity of the color.
Must be between 0 and 1, inclusive
@return [Color] The resulting color @see hsl @raise [ArgumentError] if `saturation`, `lightness`, or `alpha` are out of bounds
Returns the hue component of a color.
See [the CSS3 HSL specification](en.wikipedia.org/wiki/HSL_and_HSV#Conversion_from_RGB_to_HSL_or_HSV).
Calculated from RGB where necessary via [this algorithm](en.wikipedia.org/wiki/HSL_and_HSV#Conversion_from_RGB_to_HSL_or_HSV).
@param color [Color] @return [Number] between 0deg and 360deg @see adjust_hue @raise [ArgumentError] if `color` isn‘t a color
Returns one of two values based on the truth value of the first argument.
@example
if(true, 1px, 2px) => 1px if(false, 1px, 2px) => 2px
@param condition [Bool] Whether the first or second value will be returned. @param if_true [Literal] The value that will be returned if `$condition` is true. @param if_false [Literal] The value that will be returned if `$condition` is false.
Returns the position of the given value within the given list. If not found, returns false.
@example
index(1px solid red, solid) => 2 index(1px solid red, dashed) => false
Joins together two lists into a new list.
Unless the `$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.
@example
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
@overload join(list1, list2, separator: auto)
@param list1 [Literal] The first list to join @param list2 [Literal] The second list to join @param separator [String] 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.
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.
@example
lighten(hsl(0, 0%, 0%), 30%) => hsl(0, 0, 30) lighten(#800, 20%) => #e00
@param color [Color] @param amount [Number] @return [Color] @see darken @raise [ArgumentError] If `color` isn‘t a color,
or `number` isn't a number between 0% and 100%
Returns the hue component of a color.
See [the CSS3 HSL specification](en.wikipedia.org/wiki/HSL_and_HSV#Conversion_from_RGB_to_HSL_or_HSV).
Calculated from RGB where necessary via [this algorithm](en.wikipedia.org/wiki/HSL_and_HSV#Conversion_from_RGB_to_HSL_or_HSV).
@param color [Color] @return [Number] between 0% and 100% @see lighten @see darken @raise [ArgumentError] if `color` isn‘t a 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.
@example
mix(#f00, #00f) => #7f007f mix(#f00, #00f, 25%) => #3f00bf mix(rgba(255, 0, 0, 0.5), #00f) => rgba(63, 0, 191, 0.75)
@overload mix(color1, color2, weight: 50%)
@param color1 [Color] @param color2 [Color] @param weight [Number] between 0% and 100% @return [Color] @raise [ArgumentError] if `color1` or `color2` aren't colors, or `weight` isn't a number between 0% and 100%
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.
@example
nth(10px 20px 30px, 1) => 10px nth((Helvetica, Arial, sans-serif), 3) => sans-serif
@param list [Literal] The list @param n [Number] The index into the list @return [Literal] The nth item in the list @raise [ArgumentError] If `n` isn‘t an integer between 1 and the list‘s length.
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.
@example
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
@param color [Color] @param amount [Number] @return [Color] @see transparentize @raise [ArgumentError] If `color` isn‘t a color,
or `number` isn't a number between 0 and 1
Converts a decimal number to a percentage.
@example
percentage(100px / 50px) => 200%
@param value [Number] The decimal number to convert to a percentage @return [Number] The percentage @raise [ArgumentError] If `value` isn‘t a unitless number
@see rgb @overload rgba(red, green, blue, alpha)
Creates a {Color} object from red, green, and blue values, as well as an alpha channel indicating opacity. @param red [Number] A number between 0 and 255 inclusive @param green [Number] A number between 0 and 255 inclusive @param blue [Number] A number between 0 and 255 inclusive @param alpha [Number] A number between 0 and 1 @return [Color]
Sets the opacity of a color. @example rgba(#102030, 0.5) => rgba(16, 32, 48, 0.5) rgba(blue, 0.2) => rgba(0, 0, 255, 0.2) @param color [Color] @param alpha [Number] A number between 0 and 1 @return [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.
@example
saturate(hsl(120, 30%, 90%), 20%) => hsl(120, 50%, 90%) saturate(#855, 20%) => #9e3f3f
@param color [Color] @param amount [Number] @return [Color] @see desaturate @raise [ArgumentError] If `color` isn‘t a color,
or `number` isn't a number between 0% and 100%
Returns the saturation component of a color.
See [the CSS3 HSL specification](en.wikipedia.org/wiki/HSL_and_HSV#Conversion_from_RGB_to_HSL_or_HSV).
Calculated from RGB where necessary via [this algorithm](en.wikipedia.org/wiki/HSL_and_HSV#Conversion_from_RGB_to_HSL_or_HSV).
@param color [Color] @return [Number] between 0% and 100% @see saturate @see desaturate @raise [ArgumentError] if `color` isn‘t a color
Scales one or more properties of a color by a percentage value. Unlike \{adjust_color adjust-color}, which changes a color‘s properties by fixed amounts, \{scale_color 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 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.
@example
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)
@param color [Color] @param red [Number] @param green [Number] @param blue [Number] @param saturation [Number] @param lightness [Number] @param alpha [Number] @return [Color] @raise [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.
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.
@example
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)
@param color [Color] @param amount [Number] @return [Color] @see opacify @raise [ArgumentError] If `color` isn‘t a color,
or `number` isn't a number between 0 and 1
Inspects the type of the argument, returning it as an unquoted string.
@example
type-of(100px) => number type-of(asdf) => string type-of("asdf") => string type-of(true) => bool type-of(#fff) => color type-of(blue) => color
@param value [Literal] The object to inspect @return [String] The unquoted string name of the literal‘s type
Inspects the unit of the number, returning it as a quoted string. Complex units are sorted in alphabetical order by numerator and denominator.
@example
unit(100) => "" unit(100px) => "px" unit(3em) => "em" unit(10px * 5em) => "em*px" unit(10px * 5em / 30cm / 1rem) => "em*px/cm*rem"
@param number [Literal] The number to inspect @return [String] The unit(s) of the number @raise [ArgumentError] if `number` isn‘t a number