🎨 Couleur: A modern PHP 8.1+ color library

• 🎨 Couleur: A modern PHP 8.1+ color library
  • 👋 Presentation
  • ⚙️ Installation
  • 🏁 Quick Start
  • 📚 Usage
    • 🏭 Immutable Objects and the ColorFactory
      • Direct instanciation
      • Using the ColorFactory
      • Using immutable color objects
    • 🧰 Pure Functions
      • Color Space Functions
      • Conversion Functions
      • Generic Functions
    • 🛠️ Enums and Constants
      • The Constant Enum
      • The ColorSpace Enum
      • The CssColor Enum
  • 🌈 Color Spaces
    • CSS
    • Hexadecimal RGB
    • HSL
    • HSV
    • HWB
    • Lab
    • Lch
    • Linear RGB
    • Linear P3
    • Linear ProPhoto
    • OkLab
    • OkLch
    • P3
    • ProPhoto
    • RGB
    • XYZ-D50
    • XYZ-D65
  • 🤝 Contributing
  • 📜 License
  • ❤️ Thanks

👋 Presentation

Couleur is a modern PHP 8.1+ color library, intended to be compatible with CSS Color Module Level 4, and inspired by Color.js from Lea Verou and Chris Lilley.

The main goal of this package is to allow color conversions between multiple, old and new 🌈 Color Spaces, like the famous LCH which provides many advantages for design purpose.

Couleur is made to be usable with an OOP approach as well as with a FP approach:

• If you prefer OOP, you can use 🏭 Immutable Objects and the ColorFactory ;
• If you prefer FP, you can directly use the multiple 🧰 Pure Functions ;

Warning: This package is currently under development.

The current version may include bugs, untested code, undocumented code, unfinished code, or simply code that will change. More specifically, for the moment there is a lack of unit tests, and a few color spaces as well as distance calculation functions and gammut correction remain to be implemented. All of these will come soon.

In the meantime, it is recommended to avoid using this package in production.

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⚙️ Installation

Use the following command to add Couleur to your project with Composer:

composer require matthieumastadenis/couleur

Don't forget to include the autoloader provided by Composer:

<?php

require 'vendor/autoload.php';

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🏁 Quick Start

The following is a quick tl;dr example of the simplest way to use Couleur, based on an OOP approach. For more detailed instructions, please read the 📚 Usage section.

<?php

use matthieumastadenis\couleur\ColorFactory;
use matthieumastadenis\couleur\ColorSpace;

require 'vendor/autoload.php';

// Create a new colors\Css instance from an HSL array:
$css1 = ColorFactory::newCss([ 0, 100, 50 ], ColorSpace::Hsl);
echo $css1; // Prints 'red'

// Convert to RGB:
$rgb1 = $css1->toRgb();

// Stringify:
echo $rgb1;                                          // Prints 'rgb(100% 0% 0%)'
echo $rgb1->stringify();                             // Prints 'rgb(100% 0% 0%)'
echo $rgb1->stringify(legacy : false, alpha : true); // Prints 'rgb(100% 0% 0% / 100%)'
echo $rgb1->stringify(legacy : true);                // Prints 'rgb(255,0,0)'
echo $rgb1->stringify(legacy : true, alpha : true);  // Prints 'rgba(255,0,0,1)'

// Create a variant color:
$rgb2 = $rgb1->change('-35', '+20', 60);
echo $rgb2->stringify(legacy : true); // Prints 'rgb(220,20,60)';

// Convert to CSS:
$css2 = $rgb2->toCss();
echo $css2; // Prints 'crimson'

// Convert to Lch:
$lch = $css2->toLch();
echo $lch->stringify(alpha : true); // Prints 'lch(47.878646049% 79.619059282 26.464486652deg / 100%)'

// Convert to P3:
$p3 = $lch->toP3();
echo $p3; // Prints 'color(display-p3 0.791710722 0.191507424 0.257366748)'

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📚 Usage

🏭 Immutable Objects and the ColorFactory

Direct instanciation

Couleur provides one immutable class for each supported 🌈 Color Space. You can of course instantiate these classes manually:

<?php

use matthieumastadenis\couleur\colors\Rgb;
use matthieumastadenis\couleur\colors\Hsl;

require 'vendor/autoload.php';

// Create a new colors\Css instance:
$rgb = new Css('red');

// Create a new colors\HexRgb instance (with 50% opacity):
$hex = new HexRgb('FF', '00', '00', '80');

// Create a new colors\Hsl instance (with 50% opacity):
$hsl = new Hsl(0, 100, 50, 50);

// Create a new colors\Rgb instance (with 50% opacity):
$rgb = new Rgb(255, 0, 0, 127.5);

Note : You may have noticed from the previous example that it implies passing correctly formatted values to each constructor.

For example, the Rgb class expects to receive opacity expressed in the same magnitude than red, green and blue values, meaning as a number between 0 and 255. Same thing for the HexRgb class which expects only hexadecimal strings for each of the four parameters it takes (opacity included).

Because of this, you may prefer to avoid instanciating these classes yourself. A simpler solution is to use the ColorFactory like in the following examples. It will automatically handle values conversion for you.

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Using the ColorFactory

The best and simplest way to create color objects is by using the ColorFactory abstract class which provides a specific static method for each supported 🌈 Color Space:

<?php

use matthieumastadenis\couleur\ColorFactory;

require 'vendor/autoload.php';

// Returns a new colors\Rgb instance (with 50% opacity):
$rgb1 = ColorFactory::newRgb('rgba(255,0,0,.5)');

// Returns a new colors\Lab instance:
$lab1 = ColorFactory::newLab('lab(54.29%,80.80,69.89,1)');

// Using a string value formatted with modern CSS syntax works as well:
$rgb2 = ColorFactory::newRgb('rgb(100% 0% 0% / 50%)');
$lab2 = ColorFactory::newLab('lab(54.29% 80.80 69.89 / 100%)');

// Using an array as a value also works:
$rgb3 = ColorFactory::newRgb([ 255, 0, 0, 127.5 ]);
$lab3 = ColorFactory::newLab([ 54.29, 80.80, 69.89, 100 ]);

Note that by default these methods are automatically guessing the input syntax. This means it's possible to provide an input value in a different format than the expected output, and the conversion will happen automatically:

<?php

use matthieumastadenis\couleur\ColorFactory;

require 'vendor/autoload.php';

// Returns a new colors\Rgb instance from a CSS input:
$rgb = ColorFactory::newRgb('red');

// Returns a new colors\Css instance from a HSL input:
$css = ColorFactory::newCss('hsl(0deg,100%,50%)');

// Returns a new colors\XyzD65 instance from a Lab input:
$xyzD65 = ColorFactory::newXyzD65('lab(54.29% 80.80 69.89 / 100%)');

If you use an incorrectly formated value, a UnknownColorSpace Exception will be thrown:

<?php

use matthieumastadenis\couleur\ColorFactory;

require 'vendor/autoload.php';

try {
    // Throws a UnknownColorSpace Exception:
    $rgb = ColorFactory::newRgb('not valid');
}
catch (\Exception $e) {
    die($e); // Unknown color space
}

Also if you use an incomplete value, a MissingColorValue Exception will be thrown:

<?php

use matthieumastadenis\couleur\ColorFactory;

require 'vendor/autoload.php';

try {
    // Throws a MissingColorValue Exception:
    $rgb = ColorFactory::newRgb('rgb(255,0)');
}
catch (\Exception $e) {
    die($e); // Color value "blue" is missing
}

By using the $from parameter, you can specify the input color space with a string alias or with the ColorSpace enum. Like before, the value will automatically be converted from it to the targetted space.

Specifying this is particularly helpful when you're using an array as input, to be sure it will not be treated as RGB (which is the default for an array of numbers):

<?php

use matthieumastadenis\couleur\ColorFactory;
use matthieumastadenis\couleur\ColorSpace;

require 'vendor/autoload.php';

// Without the $from parameter, array values are considered as RGB values by default:
$rgb1 = ColorFactory::newRgb([ 0, 100, 50 ]);
\var_dump($rgb1->coordinates()); // [ 0, 100, 50, 255 ]

// With the $from parameter, we can ensure that the input value will be treated like we want
// The following line creates a new colors\Rgb instance from an HSL input:
$rgb2 = ColorFactory::newRgb([ 0, 100, 50 ], 'hsl');
\var_dump($rgb2->coordinates()); // [ 255, 0, 0, 255 ]

// Same result, but with usage of the ColorSpace enum:
$rgb3 = ColorFactory::newRgb([ 0, 100, 50 ], ColorSpace::Hsl);
\var_dump($rgb3->coordinates()); // [ 255, 0, 0, 255 ]

You can alternatively use the new() static method, which adds a $to parameter just after the input value. If this parameter is not specified, the targetted color space will automatically be determined according to the format of the value:

<?php

use matthieumastadenis\couleur\ColorFactory;
use matthieumastadenis\couleur\ColorSpace;

require 'vendor/autoload.php';

// Returns a new colors\Rgb instance (space guessed automatically):
$rgb = ColorFactory::new('rgb(255,0,0)');

// Returns a new colors\HexRgb instance (space guessed automatically):
$hex = ColorFactory::new('#ff0000');

// Returns a new colors\Css instance (space guessed automatically):
$css = ColorFactory::new('red');

// Returns a new colors\Css instance from an RGB value:
$css = ColorFactory::new('rgb(255,0,0)', 'css');

// Same result but using the ColorSpace enum:
$css = ColorFactory::new('rgb(255,0,0)', ColorSpace::Css);

// Returns a new colors\Lch instance (using the ColorSpace enum):
$lch = ColorFactory::new([ 54.29, 106.84, 40.86 ], ColorSpace::Lch);

// Returns a new colors\OkLab instance from an RGB value (using the ColorSpace enum):
$okLab = ColorFactory::new([ 255, 0, 0 ], ColorSpace::OkLab, ColorSpace::Rgb);

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Using immutable color objects

Once you have a color instance, you can easily convert it to another color space using one of its dedicated to...() methods, which will return a new object:

<?php

use matthieumastadenis\couleur\ColorFactory;
use matthieumastadenis\couleur\ColorSpace;

require 'vendor/autoload.php';

$rgb = ColorFactory::newRgb([ 255, 0, 0 ]);

// Converting to a new colors\Css instance:
$css = $rgb->toCss();

// Converting to a new colors\XyzD50 instance:
$xyzD50 = $css->toXyzD50();

// Converting to a new colors\OkLch instance (using the to() method):
$okLch = $xyzD50->to(ColorSpace::OkLch);

Note that any color can be converted to CSS with the toCss() method. It will automatically pick the closest CSS color:

<?php

use matthieumastadenis\couleur\ColorFactory;

require 'vendor/autoload.php';

$rgb = ColorFactory::newRgb([ 250, 10, 10 ]);
$css = $rgb->toCss();

// Prints 'red':
echo $css;

All color objects are directly stringable. They also provide a stringify() method which offers more possibilities:

<?php

use matthieumastadenis\couleur\ColorFactory;
use matthieumastadenis\couleur\ColorSpace;

require 'vendor/autoload.php';

$rgb = ColorFactory::newRgb([ 255, 0, 0 ]);

// Prints 'rgb(100% 0% 0%)':
echo $rgb;

// Prints 'rgb(100% 0% 0% / 100%)' ($alpha parameter):
echo $rgb->stringify(null, true);

// Prints 'rgba(255,0,0,1)' (using $legacy and $alpha parameters):
echo $rgb->stringify(true, true);

$lch = ColorFactory::newLch([ 54.2905429, 106.837191, 40.8576688 ], ColorSpace::Lch);

// Prints 'lch(54.29% 106.84 40.86deg)' Using the $precision parameter:
echo $lch->stringify(precision : 2);

All color objects also have a coordinates() method which returns an array:

<?php

use matthieumastadenis\couleur\ColorFactory;

require 'vendor/autoload.php';

$hex = ColorFactory::newHexRgb('#F00');

// Returns [ 'FF', '00', '00', 'FF' ]:
$values = $hex->coordinates();

You can also directly access readonly properties from each color object:

<?php

use matthieumastadenis\couleur\ColorFactory;

require 'vendor/autoload.php';

$rgb = ColorFactory::newRgb([ 255, 0, 0 ]);

// Prints 255:
echo $rgb->red;

$hsl = ColorFactory::newHsl([ 0, 100, 50 ]);

// Prints 50:
echo $hsl->lightness;

All color objects have a change() method which always return a new object corresponding to a variant of the current color.

<?php

use matthieumastadenis\couleur\ColorFactory;
use matthieumastadenis\couleur\ColorSpace;

require 'vendor/autoload.php';

$hsl1 = ColorFactory::newHsl([ 0, 100, 50, 100 ], ColorSpace::Hsl);
echo $hsl1; // hsl(0deg 100% 50% / 100%)

// Redefining coordinates:
$hsl2 = $hsl1->change(hue : 180, opacity : 80);
echo $hsl2; // hsl(180deg 100% 50% / 80%)

// Add, subtract, multiply, divide coordinates:
$hsl3 = $hsl2->change('+20', '-10', '*1.5', '/2');
echo $hsl3; // hsl(200deg 90% 75% / 40%)

// Reduce coordinates by modulus:
$hsl4 = $hsl3->change(opacity : '%6');
echo $hsl4; // hsl(200deg 90% 75% / 4%)

// Calculate the percentage of coordinates:
$hsl5 = $hsl4->change('50%');
echo $hsl5; // hsl(100deg 90% 75% / 4%)

// Add, subtract, multiply, divide coordinates by a percentage:
$hsl6 = $hsl5->change('+50%', '-50%', '/10%', '*200%');
echo $hsl6; // hsl(150deg 45% 10% / 32%)

// Reduce coordinates by a percentage modulus:
$hsl7 = $hsl6->change(saturation : '%20%');
echo $hsl7; // hsl(150deg 0% 10% / 32%)

Note: The change() method of the HexRgb class behave differently depending on the operation you ask for :

• For replacing a coordinate you have to provide an hexadecimal value ;
• For additions and substractions you have to provide an hexadecimal value ;
• For all other operactions you have to provide a decimal value ;

Please observe the detailed demonstration in the next example:

<?php

use matthieumastadenis\couleur\ColorFactory;
use matthieumastadenis\couleur\ColorSpace;

require 'vendor/autoload.php';

$hex1 = ColorFactory::newHexRgb('#F00');
echo $hex1; // #F00

// When replacing coordinates, provide hexadecimal numbers:
$hex2 = $hex1->change('80', 'AA', 'BB', 'AA');
echo $hex2; // #80AABBAA

// When adding or subtracting coordinates, provide hexadecimal numbers:
$hex3 = $hex2->change('+8', '-11');
echo $hex3; // #89BA (88 99 BB AA)

// When multiplying, dividing or reducing coordinates by modulo, provide decimal numbers:
$hex4 = $hex3->change(null, '*1.5', '/2', '%3');
echo $hex4; // #88E65E02 (88 dechex(153*1.5) dechex(187/2) dechex(170%3))

// When using percentages, provide decimal numbers:
$hex5 = $hex4->change('20%');
echo $hex5; // #1BE65E02 (dechex(136*20/100) E6 5E 02)

// When using percentages with addition, substraction, multiplication or division, provide decimal numbers:
$hex6 = $hex5->change('+50%', '-20%', '/2%', '*200%');
echo $hex6; // #29B83208 (dechex(27+(27*50/100)) dechex(230-(230*20/100)) dechex(94/(84*2/100)) dechex(2*(2*200/100)))

// When using percentages with modulo, provide decimal numbers:
$hex7 = $hex6->change(green : '%4%');
echo $hex7; // #29023208 (29 dechex(184%(184*4/100)) 32 08)

Note: The change() method of the Css class also behave differently: it only accepts a stringable color name or an instances of the CssColor Enum, which replace the color without variations.

Please observe the next example:

<?php

use matthieumastadenis\couleur\ColorFactory;
use matthieumastadenis\couleur\CssColor;

require 'vendor/autoload.php';

$css1 = ColorFactory::newCss(CssColor::red);
echo $css1; // red

$css2 = $css1->change(CssColor::purple);
echo $css2; // purple

$css2 = $css1->change(CssColor::purple);
echo $css2; // purple

$css3 = $css2->change('hotpink');
echo $css3; // hotpink

// Throws an UnsupportedCssColor Exception:
$css4 = $css3->change('invalid');

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🧰 Pure Functions

Objects in Couleur are all based on a collection of pure functions under the hood. These functions can be used directly if you don't want to use objects.

Note: Choosing this functional programming approach is better in terms of performance, but can be a bit more tedious because you have to manipulate arrays of values instead of objects.

There are three main types of functions provided by Couleur : dedicated Color Space Functions, dedicated Conversion Functions, and Generic Functions:

Color Space Functions

Each supported 🌈 Color Space has its own dedicated functions, accessible under the namespace matthieumastadenis\couleur\utils\[space]. Those are the same for each color space: clean(), from(), stringify() and verify().

clean() functions are made to transform an input value in a correctly formated set of values, according to the corresponding color space. They all return an array, except for css\clean() which directly returns an instance of the the CssColor Enum:

<?php

use matthieumastadenis\couleur\utils\css;
use matthieumastadenis\couleur\utils\rgb;
use matthieumastadenis\couleur\utils\lch;

require 'vendor/autoload.php';

// All of the following return ColorSpace::red:
$css1 = css\clean('red');
$css2 = css\clean(' red ');
$css3 = css\clean('RED');

// All of the following return [ 255, 0, 0, 255 ]:
$rgb1 = rgb\clean([ '100%', '0%', '0%', '100%' ]);
$rgb2 = rgb\clean([ 255, 0, 0, '100%' ]);
$rgb3 = rgb\clean('rgb(255,0,0)');
$rgb4 = rgb\clean('rgba(255,0,0,1)');
$rgb5 = rgb\clean('rgb(100% 0 0 / 100%)');
$rgb6 = rgb\clean('color(rgb 100% 0 0 / 100%)');

// All of the following return [ 54.2905429, 106.837191, 40.8576688, 100 ]:
$lch1 = lch\clean([ 54.2905429, 106.837191, 40.8576688 ]);
$lch2 = lch\clean([ '54.2905429%', '106.837191', '40.8576688deg' ]);
$lch3 = lch\clean('lch(54.2905429%,106.837191,40.8576688deg)');
$lch4 = lch\clean('lch(54.2905429% 106.837191 40.8576688deg / 100%)');
$lch5 = lch\clean('color(lch 54.2905429% 106.837191 40.8576688deg)');
$lch6 = lch\clean('color(lch 54.2905429% 106.837191 40.8576688deg / 100%)');

from() functions convert and clean an input value from the specified color space (with the $from parameter) to the color space corresponding to the used namespace. If no input color space is specified with the $from parameter, it will be automatically guessed from the format of the $value:

<?php

use matthieumastadenis\couleur\utils\rgb;
use matthieumastadenis\couleur\utils\lch;
use matthieumastadenis\couleur\ColorSpace;

require 'vendor/autoload.php';

// All of the following convert and clean from CSS to RGB,
// returning [ 255, 0, 0, 255 ]:
$rgb1 = rgb\from('red');
$rgb2 = rgb\from('red', ColorSpace::Css);

// All of the following convert and clean from RGB to HSL,
// returning [ 0, 100, 50, 100 ]:
$hsl1 = hsl\from([ 255, 0, 0, 255 ]);
$hsl2 = hsl\from('rgb(100% 0% 0% / 100%)');
$hsl3 = hsl\from('rgba(255,0,0,1)', 'rgb');
$hsl4 = hsl\from('rgba(255,0,0,1)', ColorSpace::Rgb);

stringify() functions return a color string fully compatible with CSS syntax. Depending of each color space, these functions can have the following parameters:

• $sharp : only for HexRgb colors, this can be used to include or not the hexadecimal sharp character (#) ;
• $short : only for HexRgb colors, this can be used to force or prevent the shortening of the value (#f00 instead of #ff0000) ;
• $uppercase : only for HexRgb colors, this can be used to force the conversion to uppercase or lowercase (by default the case is preserved) ;
• $alpha : can be used to force or prevent the inclusion of opacity (by default opacity is included only if it has a value other than 100%) ;
• $precision : number of decimals used to round values (by defaut the COULEUR_PRECISION constant is used) ;
• $legacy : if true the color string will be formatted according to the traditional CSS syntax rather than the modern one (rgba(255,0,0,1) instead of rgb(100% 0% 0% / 100%)) ;

<?php

use matthieumastadenis\couleur\utils\hexRgb;
use matthieumastadenis\couleur\utils\rgb;
use matthieumastadenis\couleur\utils\xyzD65;

require 'vendor/autoload.php';

// Prints '#F00':
echo hexRgb\stringify('FF', '00', '00');

// Prints 'FF0' (using the $sharp parameter):
echo hexRgb\stringify('FF', '00', '00', sharp : false);

// Prints '#F00' (using array destructuring on clean() result):
echo hexRgb\stringify(... hexRgb\clean('#FF0000'));

// Prints '#FF0000' (using $short parameter):
echo hexRgb\stringify('FF', '00', '00', short : false);

// Prints '#F00F' (using $alpha parameter):
echo hexRgb\stringify('FF', '00', '00', alpha : true);

// Prints '#FF0000FF' (using $alpha and $short parameters):
echo hexRgb\stringify('FF', '00', '00', alpha : true, short : false);

// Prints 'rgb(100% 0% 0%)':
echo rgb\stringify(255, 0, 0);

// Prints 'rgb(100% 0% 0%)' (using array destructuring on clean() result):
echo rgb\stringify(... rgb\clean('rgb(255,0,0,1)'));

// Prints 'rgb(100% 0% 0% / 100%)' (using $alpha parameter):
echo rgb\stringify(255, 0, 0, alpha : true);

// Prints 'rgb(255,0,0)' (using $legacy parameter):
echo rgb\stringify(255, 0, 0, legacy : true);

// Prints 'rgba(255,0,0,1)' (using $legacy and $alpha parameters):
echo rgb\stringify(255, 0, 0, legacy : true, alpha : true);

// Prints 'color(xyz-d65 0.412390799 0.212639006 0.019330819)':
echo xyzD65\stringify(0.412390799, 0.212639006, 0.019330819);

// Prints 'color(xyz-d65 0.412390799 0.212639006 0.019330819 / 100%)' (using $alpha parameter):
echo xyzD65\stringify(0.412390799, 0.212639006, 0.019330819, alpha : true);

verify() functions simply return a boolean indicating if the input value matches the corresponding color space:

<?php

use matthieumastadenis\couleur\utils\css;
use matthieumastadenis\couleur\utils\hexRgb;
use matthieumastadenis\couleur\utils\hsl;

require 'vendor/autoload.php';

// Returns true:
\var_dump(css\verify('red'));

// Returns false:
\var_dump(css\verify('invalid'));

// All of the following return true:
\var_dump(hexRgb\verify('f00'));
\var_dump(hexRgb\verify('f00f'));
\var_dump(hexRgb\verify('ff0000'));
\var_dump(hexRgb\verify('ff0000ff'));
\var_dump(hexRgb\verify('#f00'));
\var_dump(hexRgb\verify('#f00f'));
\var_dump(hexRgb\verify('#ff0000'));
\var_dump(hexRgb\verify('#ff0000ff'));

// Returns false:
\var_dump(hexRgb\verify('invalid'));

// The following also return false, because they eventually could be mistaken for RGB values:
\var_dump(hexRgb\verify([ 'ff', '00', '00' ]));
\var_dump(hexRgb\verify([ 'ff', '00', '00', 'ff' ]));

// All of the following return true:
\var_dump(hsl\verify('hsl(0,100,50)'));
\var_dump(hsl\verify('hsl(0deg,100%,50%)'));
\var_dump(hsl\verify('hsla(0,100,50,1)'));
\var_dump(hsl\verify('hsla(0deg,100%,50%,1)'));
\var_dump(hsl\verify('color(hsl,0,100,50,1)'));
\var_dump(hsl\verify('color(hsl,0deg,100%,50%,1)'));
\var_dump(hsl\verify('color(hsl 0 100 50 / 1)'));
\var_dump(hsl\verify('color(hsl 0deg 100% 50% / 1)'));

// All of the following return false:
\var_dump(hsl\verify('0,100,50'));
\var_dump(hsl\verify('hsl 0,100'));

// The following also return false, because they eventually could be mistaken for RGB values:
\var_dump(hexRgb\verify([ 0, 100, 50 ]));
\var_dump(hexRgb\verify([ '0deg', '100%', '50%' ]));

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Conversion Functions

Each supported 🌈 Color Space has a complete set of dedicated functions to convert into other color spaces. These are also accessible under the namespace matthieumastadenis\couleur\utils\[space]:

<?php

use matthieumastadenis\couleur\utils\css;
use matthieumastadenis\couleur\utils\rgb;
use matthieumastadenis\couleur\CssColor;

require 'vendor/autoload.php';

// Returns [ 255, 0, 0, 255 ]:
$rgb = css\toRgb(CssColor::red);

// Returns [ 0, 100, 50, 100 ]:
$hsl = rgb\toHsl(... $rgb);

// Returns [  0.43606574282481, 0.22249319175624, 0.013923904500943, 1 ]
$xyzD50 = hsl\toXyzD50(... $hsl);

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Generic Functions

Couleur also offers an ensemble of generic utilitary functions, all located under the namespace matthieumastadenis\couleur\utils.

If the majority of these functions are mostly made for interal usages, a few can be useful to you if you prefer to use Couleur with a functional programming approcach. These are described below.

The constant() function can be used to access and declare configuration constants direclty, without the need to use the Constant Enum:

<?php

use matthieumastadenis\couleur\utils;

require 'vendor/autoload.php';

// Returns null:
\var_dump(utils\constant('unknown'));

// Returns 7:
\var_dump(utils\constant('precision', 7));

// Creates the constant with a value of 3, then returns 3:
\var_dump(utils\constant('precision', 3, true));

// Now that the constant was created, always returns 3:
\var_dump(utils\constant('precision'));

The findColorSpace() function helps you to guess a 🌈 Color Space by interpreting a provided $value.

If the function succeeds, it returns an instance of the ColorSpace Enum.

In case of failure, the function will throw a UnknownColorSpace by default, except if you set the $throw parameter to false or if you provide a $fallback value.

<?php

use matthieumastadenis\couleur\utils;
use matthieumastadenis\couleur\ColorSpace;

require 'vendor/autoload.php';

// Returns ColorSpace::Css:
$space = utils\findColorSpace('red');

// Returns ColorSpace::Rgb:
$space = utils\findColorSpace('rgba(255,0,0,1)');

// Also returns ColorSpace::Rgb:
$space = utils\findColorSpace([ 255, 0, 0, 255 ]);

// Throws a UnknownColorSpace Exception:
$space = utils\findColorSpace('invalid');

// Returns ColorSpace::Rgb (using the $fallback parameter):
$space = utils\findColorSpace('invalid', ColorSpace::Rgb);

// Returns null (using the $throw parameter):
$space = utils\findColorSpace('invalid', throw : false);

The isColorString() function returns a boolean indicating if the provided $value is a valid CSS color string.

By default it is very tolerant and will return true for any string corresponding to a valid CSS syntax, regardless of how you wrote the function name (meaning something like 'myCustomRgb(255,0,0)' will be considered as valid).

If you want a more precise check, you can use the $spaces parameter to provide either:

• an unique stringable value, like 'rgb' ;
• an array of accepted values, like [ 'rgb', 'rgba' ] ;
• an instance of the ColorSpace Enum (all of its aliases will be accepted) ;

<?php

use matthieumastadenis\couleur\utils;
use matthieumastadenis\couleur\ColorSpace;

require 'vendor/autoload.php';

// All of the following return true:
\var_dump(utils\isColorString('myCustomColor(255,0,0,1)'));
\var_dump(utils\isColorString('rgb(100% 0% 0% / 100%)', 'rgb'));
\var_dump(utils\isColorString('rgba(255,0,0,1)', [ 'rgb', 'rgba' ]));
\var_dump(utils\isColorString('color(srgb 100% 0% 0% / 100%)', ColorSpace::Rgb));

// All of the following return false:
\var_dump(utils\isColorString('invalid'));
\var_dump(utils\isColorString('rgb 100%'));
\var_dump(utils\isColorString('255,0,0'));
\var_dump(utils\isColorString('rgba(255,0,0,1)', 'rgb'));
\var_dump(utils\isColorString('srgb(255,0,0,1)', [ 'rgb', 'rgba' ]));
\var_dump(utils\isColorString('myCustomRgb( 100% 0% 0% / 100%)', ColorSpace::Rgb));
\var_dump(utils\isColorString('color(myCustomRgb 100% 0% 0% / 100%)', ColorSpace::Rgb));

The parseColorValue() function transforms a CSS color string into an array of values. If the provided $value is not stringable, it will simply be returned as an array.

The $opacityFactor parameter is useful to convert opacity into the correct range (for example converting 1 to 100 or 255).

Note : This function does not clean values inside of the array. For a typical usage, you may want to pass its result into the corresponding clean() function (see the Color Space Functions section for more details).

<?php

use matthieumastadenis\couleur\utils;
use matthieumastadenis\couleur\CssColor;

require 'vendor/autoload.php';

// Returns [ 255, 0, 0 ]:
$values = utils\parseColorValue('rgb(255,0,0)');

// Returns [ 255, 0, 0, 1 ]:
$values = utils\parseColorValue('rgb(255,0,0,1)');

// Returns [ 255, 0, 0, 255 ] (using the $opacityFactor parameter):
$values = utils\parseColorValue('rgb(255,0,0,1)', 255);

// Returns [ '100%', '0%', '0%', '100%' ]:
$values = utils\parseColorValue('rgb(100% 0% 0% / 100%)');

// Returns [ CssColor::red ]
$values = utils\parseColorValue(CssColor::red);

// Returns [ 255, 0, 0, 255 ]:
$values = utils\parseColorValue([ 255, 0, 0, 255 ]);

The to() function is the highest-level function used to convert any color value to any color space.

In case of success, its result will always be an array.

Its $to and $from parameters correspond respectively to the output and input color spaces, and accept either an instance of the ColorSpace Enum or a stringable value corresponding to a valid color space alias (you can find all valid aliases listed below in the 🌈 Color Spaces section).

If these parameters are null, they will be guessed by interpreting the format of $value (using the findColorSpace() function).

<?php

use matthieumastadenis\couleur\utils;
use matthieumastadenis\couleur\ColorSpace;

require 'vendor/autoload.php';

// Returns [ CssColor::red ]:
// ('red' is a valid CSS color so we can omit the $from parameter):
$css = utils\to('red', 'css');

// Returns [ 255, 0, 0, 255 ]:
// ([ CssColor::red ] is a valid CSS color so we can omit the $from parameter):
$rgb = utils\to($css, ColorSpace::Rgb);

// Returns [ 0, 100, 50, 100 ]:
// ([ 255, 0, 0, 255 ] is a valid RGB color so we can omit the $from parameter):
$hsl = utils\to($rgb, ColorSpace::Hsl);

// Returns [ 54.29054294697, 80.804920334624, 69.890988258963, 100 ]
// (the $from parameter avoids HSL array being interpreted as RGB):
$lab = utils\to($hsl, ColorSpace::Lab, ColorSpace::Hsl);

// Returns [ 54.29054294697, 106.83719104366, 40.857668782131, 100 ]
// (the $from parameter avoids Lab array being interpreted as RGB):
$lch = utils\to($lab, ColorSpace::Lch, ColorSpace::Lab);

// Returns [ 0.41239079028139, 0.21263903420017, 0.01933077971095, 100 ]
// (the $from parameter avoids Lch array being interpreted as RGB):
$xyzD65 = utils\to($lch, ColorSpace::XyzD65, ColorSpace::Lch);

// Returns [ 0.70226883304033, 0.27562276714962, 0.10344904551878, 1 ]
// (here we use a valid string input so we can omit the $from paramter):
$proPhoto = utils\to('color(xyz-d65 0.4124 0.2126 0.0193 / 100%)', ColorSpace::ProPhoto);

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🛠️ Enums and Constants

The Constant Enum

Couleur can be preconfigured with dedicated constants. These act as default values used by multiple functions when the corresponding parameter is missing or set to null. All constants are written in uppercase and prefixed with COULEUR_.

Currently, the following constants are used:

• COULEUR_LEGACY (default 0): if set to 1, stringified colors will use the legacy CSS syntax by default ;
• COULEUR_PRECISION (default 9): the default rounding precision for color values when stringified ;

You can use the Constant enum to easily access and manage these constants and their values:

<?php

use matthieumastadenis\couleur\Constant;

require 'vendor/autoload.php';

// Returns all Constant cases:
Constant::cases();

// Always returns 0, which is the default value for the COULEUR_LEGACY constant:
Constant::LEGACY->value;

// Always returns 9, which is the default value for the COULEUR_PRECISION constant:
Constant::PRECISION->value;

// Returns the value of the COULEUR_LEGACY constant if defined, or 0 by default:
Constant::LEGACY->value();

// Returns the value of the COULEUR_PRECISION constant if defined, or 9 by default:
Constant::PRECISION->value();

// Returns the value of the COULEUR_LEGACY constant if defined, or 1 as fallback:
Constant::LEGACY->value(1);

// Returns the value of the COULEUR_PRECISION constant if defined, or 3 as fallback:
Constant::PRECISION->value(3);

// Returns the value of the COULEUR_LEGACY constant if defined, or define it with 1 as value then returns 1:
Constant::LEGACY->value(1, true);

// Returns the value of the COULEUR_PRECISION constant if defined, or define it with 3 as value then returns 3:
Constant::PRECISION->value(3, true);

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The ColorSpace Enum

This enum is the simplest way to access all color spaces supported by Couleur:

<?php

use matthieumastadenis\couleur\ColorSpace;

require 'vendor/autoload.php';

// Returns all ColorSpace cases:
ColorSpace::cases();

You can access a ColorSpace instance by the corresponding color class:

<?php

use matthieumastadenis\couleur\ColorSpace;
use matthieumastadenis\couleur\colors\Lch;
use matthieumastadenis\couleur\colors\LinP3;
use matthieumastadenis\couleur\colors\Rgb;

require 'vendor/autoload.php';

// Returns ColorSpace::Lch:
ColorSpace::from(Lch::class);

// Returns ColorSpace::LinP3:
ColorSpace::from(LinP3::class);

// Returns ColorSpace::Rgb:
ColorSpace::from(Rgb::class);

Each ColorSpace is accessible from multiple aliases with the fromAlias() method. All aliases are case insensitive:

<?php

use matthieumastadenis\couleur\ColorSpace;

require 'vendor/autoload.php';

// Returns all ColorSpace aliases:
ColorSpace::allAliases();

// Returns aliases of the HexRgb space:
ColorSpace::HexRgb->aliases();

// Returns ColorSpace::Rgb:
ColorSpace::fromAlias('rgb');
ColorSpace::fromAlias('srgb');
ColorSpace::fromAlias('RGBA');

// Returns ColorSpace::Lab:
ColorSpace::fromAlias('lab');
ColorSpace::fromAlias('cielab');
ColorSpace::fromAlias('CIE-LAB');

You can easily access dedicated functions from each ColorSpace with the cleanCallback(), fromCallback(), stringifyCallback() and verifyCallback() methods:

<?php

use matthieumastadenis\couleur\ColorSpace;
use matthieumastadenis\couleur\CssColor;

require 'vendor/autoload.php';

// Returns 'matthieumastadenis\couleur\utils\xyzD50\clean':
ColorSpace::XyzD50->cleanCallback();

// Returns [ 255, 127.5, 0, 255 ]:
ColorSpace::Rgb->cleanCallback()('rgb(100%,50%,0)');

// Returns [ 'FF', '00', '00', 'FF' ]:
ColorSpace::HexRgb->cleanCallback()('#f00');

// Returns 'matthieumastadenis\couleur\utils\xyzD50\from':
ColorSpace::XyzD50->fromCallback();

// Returns [ 255, 0, 0, 255 ]:
ColorSpace::Rgb->fromCallback()('hsl(0deg,100%,50%)');

// Returns CssColor::red:
ColorSpace::Css->fromCallback()('#f00');

// Returns 'matthieumastadenis\couleur\utils\xyzD50\stringify':
ColorSpace::XyzD50->stringifyCallback();

// Returns 'rgb(100% 0% 0% / 50%):
ColorSpace::Rgb->stringifyCallback()(255, 0 , 0, 127.5);

// Returns '#F00':
ColorSpace::Css->stringifyCallback()(CssColor::red);

// Returns 'matthieumastadenis\couleur\utils\css\verify':
ColorSpace::Css->verifyCallback();

// Returns true:
ColorSpace::Rgb->verifyCallback()('rgb(100%,50%,0)');

// Returns false:
ColorSpace::HexRgb->verifyCallback()('#ff');

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The CssColor Enum

This enum helps managing CSS named colors. With its multiple methods, you can easily know if a CssColor exists and get the corresponding RGB or HexRGB coordinates from it:

<?php

use matthieumastadenis\couleur\CssColor;

require 'vendor/autoload.php';

// Returns all CssColor cases:
CssColor::cases();

// Returns RGB coordinates for all supported CSS colors:
CssColor::allRgbCoordinates();

// Returns HexRgb coordinates for all supported CSS colors:
CssColor::allHexRgbCoordinates();

// Returns true (the 'red' color exists):
CssColor::exists('red');

// Returns [ 255, 0, 0 ]:
CssColor::red->toRgbCoordinates();

// Returns [ 'FF', '00', '00' ]:
CssColor::red->toHexRgbCoordinates();

The fromCss() method allows you to get a specific CssColor by its name. If no supported color matches the $name parameter, a UnsupportedCssColor Exception will be thrown by default, unless you provide a $fallback or you set the $throw parameter to false.

<?php

use matthieumastadenis\couleur\CssColor;

require 'vendor/autoload.php';

// Returns CssColor::red:
CssColor::fromCss('red');

// Throws a UnsupportedCssColor Exception:
CssColor::fromCss('unknown');

// Returns CssColor::pink Exception:
CssColor::fromCss('unknown', CssColor::pink);

// Returns null:
CssColor::fromCss('unknown', null, false);

You can also find the CssColor corresponding to precise RGB or HexRGB coordinates with fromRgb() and fromHexRgb().

By default these functions will return the supported CSS color which is the closest to the provided coordinates, unless you set the $closest parameter to false. In that case and if no supported color matches the exact coordinates you provided, a UnsupportedCssColor Exception will be thrown by default, unless you provide a $fallback or you set the $throw parameter to false.

<?php

use matthieumastadenis\couleur\CssColor;

require 'vendor/autoload.php';

// Returns CssColor::red which is the closest to #FA1111:
CssColor::fromHexRgb('FA', '11', '11');

// Throws a UnsupportedCssColor Exception:
CssColor::fromHexRgb('FA', '11', '11', false);

// Returns CssColor::pink:
CssColor::fromHexRgb('FA', '11', '11', false, CssColor::pink);

// Returns null:
CssColor::fromHexRgb('FA', '11', '11', false, null, false);

// Returns CssColor::red which is the closest to rgb(250,10,10):
CssColor::fromRgb(250, 10, 10);

// Throws a UnsupportedCssColor Exception:
CssColor::fromRgb(250, 10, 10, false);

// Returns CssColor::pink:
CssColor::fromRgb(250, 10, 10, false, CssColor::pink);

// Returns null:
CssColor::fromRgb(250, 10, 10, false, null, false);

You can stringify a CssColor with the toHexRgbString() and toRgbString methods:

<?php

use matthieumastadenis\couleur\CssColor;

require 'vendor/autoload.php';

// Returns '#F00':
CssColor::red->toHexRgbString();

// Returns '#f00' (using the $uppercase parameter):
CssColor::red->toHexRgbString(uppercase : false);

// Returns 'F00' (using the $sharp parameter):
CssColor::red->toHexRgbString(sharp : false);

// Returns '#F00F' (using the $alpha parameter):
CssColor::red->toHexRgbString(true);

// Returns '#FF0000' (using the $short parameter):
CssColor::red->toHexRgbString(short : false);

// Returns '#FF0000FF' (using $alpha and $short parameters):
CssColor::red->toHexRgbString(true, false);

// Returns '#ff0000ff' (using $alpha, $short and $uppercase parameters):
CssColor::red->toHexRgbString(true, false, false);

// Returns 'ff0000ff' (using $alpha, $short, $uppercase and $sharp parameters):
CssColor::red->toHexRgbString(true, false, false, false);

// Returns 'rgb(100% 0% 0%)':
CssColor::red->toRgbString();

// Returns 'rgb(100% 0% 0% / 100%)' (using the $alpha parameter):
CssColor::red->toRgbString(alpha : true);

// Returns 'rgb(255,0,0)' (using the $legacy parameter):
CssColor::red->toRgbString(true);

// Returns 'rgba(255,0,0,1)' (using the $legacy and $alpha parameters):
CssColor::red->toRgbString(true, true);

You can also get a new Color object from any CssColor by using the toCss(), toHexRgb() or toRgb() method:

<?php

use matthieumastadenis\couleur\CssColor;

require 'vendor/autoload.php';

// Returns a new colors\Css instance:
CssColor::red->toCss();

// Returns a new colors\HexRgb instance:
CssColor::red->toHexRgb();

// Returns a new colors\Rgb instance:
CssColor::red->toRgb();

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🌈 Color Spaces

Couleur currently supports the following color spaces and formats:

CSS

In Couleur, the Css color space refers to the named colors according to the CSS specification. Because they are a predefined and standardized list of exact colors, they all can be accessed easily with the CssColor Enum.

Note : Css colors cannot have an opacity value. If you want to apply transparency to a Css color, you first have to convert it into another color space. In the same way, if you convert a color with transparency into its Css equivalent, it will lose the transparency.

• ColorSpace enum case : ColorSpace::Css ;
• Color class : matthieumastadenis\couleur\colors\Css ;
• Dedicated functions namespace : matthieumastadenis\couleur\utils\css ;
• Accepted aliases : css, html, web ;

Hexadecimal RGB

• ColorSpace case: ColorSpace::HexRgb ;
• Color class : matthieumastadenis\couleur\colors\HexRgb ;
• Dedicated functions namespace : matthieumastadenis\couleur\utils\hexRgb ;
• Accepted aliases : hex, hexrgb, hex-rgb, hex_rgb, hexadecimal ;
• Coordinates : red, green, blue ;

HSL

• ColorSpace case: ColorSpace::Hsl ;
• Color class : matthieumastadenis\couleur\colors\Hsl ;
• Dedicated functions namespace : matthieumastadenis\couleur\utils\hsl ;
• Accepted aliases : hsl, hsla ;
• Coordinates : hue, saturation, lightness ;

HSV

• ColorSpace case: ColorSpace::Hsv ;
• Color class : matthieumastadenis\couleur\colors\Hsv ;
• Dedicated functions namespace : matthieumastadenis\couleur\utils\hsv ;
• Accepted aliases : hsv, hsb ;
• Coordinates : hue, saturation, value ;

HWB

• ColorSpace case: ColorSpace::Hwb ;
• Color class : matthieumastadenis\couleur\colors\Hwb ;
• Dedicated functions namespace : matthieumastadenis\couleur\utils\hwb ;
• Accepted aliases : hwb ;
• Coordinates : hue, whiteness, blackness ;

Lab

• ColorSpace case: ColorSpace::Lab ;
• Color class : matthieumastadenis\couleur\colors\Lab ;
• Dedicated functions namespace : matthieumastadenis\couleur\utils\lab ;
• Accepted aliases : lab, cielab, cie-lab, cie_lab ;
• Coordinates : lightness, b, a ;

Lch

• ColorSpace case: ColorSpace::Lch ;
• Color class : matthieumastadenis\couleur\colors\Lch ;
• Dedicated functions namespace : matthieumastadenis\couleur\utils\lch ;
• Accepted aliases : lch, cielch, cie-lch, cie_lch ;
• Coordinates : lightness, chroma, hue ;

Linear RGB

• ColorSpace case: ColorSpace::LinRgb ;
• Color class : matthieumastadenis\couleur\colors\LinRgb ;
• Dedicated functions namespace : matthieumastadenis\couleur\utils\linRgb ;
• Accepted aliases : srgb-linear, linrgb, linsrgb, lin-rgb, lin_rgb, lin-srgb, lin_srgb ;
• Coordinates : red, green, blue ;

Linear P3

• ColorSpace case: ColorSpace::LinP3 ;
• Color class : matthieumastadenis\couleur\colors\LinP3 ;
• Dedicated functions namespace : matthieumastadenis\couleur\utils\linP3 ;
• Accepted aliases : p3-linear, p3_linear, linp3, lin-p3, lin_p3 ;
• Coordinates : red, green, blue ;

Linear ProPhoto

• ColorSpace case: ColorSpace::LinProPhoto ;
• Color class : matthieumastadenis\couleur\colors\LinProPhoto ;
• Dedicated functions namespace : matthieumastadenis\couleur\utils\linProPhoto ;
• Accepted aliases : prophoto-linear, prophoto_linear, linprophoto, lin-prophoto, lin_prophoto ;
• Coordinates : red, green, blue ;

OkLab

• ColorSpace case: ColorSpace::OkLab ;
• Color class : matthieumastadenis\couleur\colors\OkLab ;
• Dedicated functions namespace : matthieumastadenis\couleur\utils\okLab ;
• Accepted aliases : oklab, ok-lab, ok_lab ;
• Coordinates : lightness, a, b ;

OkLch

• ColorSpace case: ColorSpace::OkLch ;
• Color class : matthieumastadenis\couleur\colors\OkLch ;
• Dedicated functions namespace : matthieumastadenis\couleur\utils\okLch ;
• Accepted aliases : oklch, ok-lch, ok_lch ;
• Coordinates : lightness, chroma, hue ;

P3

• ColorSpace case: ColorSpace::LinP3 ;
• Color class : matthieumastadenis\couleur\colors\LinP3 ;
• Dedicated functions namespace : matthieumastadenis\couleur\utils\linP3 ;
• Accepted aliases : display-p3, display_p3, p3 ;
• Coordinates : red, green, blue ;

ProPhoto

• ColorSpace case: ColorSpace::ProPhoto ;
• Color class : matthieumastadenis\couleur\colors\ProPhoto ;
• Dedicated functions namespace : matthieumastadenis\couleur\utils\proPhoto ;
• Accepted aliases : prophoto, prophoto-rgb, prophoto_rgb ;
• Coordinates : red, green, blue ;

RGB

• ColorSpace case: ColorSpace::Rgb ;
• Color class : matthieumastadenis\couleur\colors\Rgb ;
• Dedicated functions namespace : matthieumastadenis\couleur\utils\rgb ;
• Accepted aliases : rgb, rgba, srgb, s-rgb, s_rgb ;
• Coordinates : red, green, blue ;

XYZ-D50

• ColorSpace case: ColorSpace::XyzD50 ;
• Color class : matthieumastadenis\couleur\colors\XyzD50 ;
• Dedicated functions namespace : matthieumastadenis\couleur\utils\xyzD50 ;
• Accepted aliases : xyz-d50, xyz_d50, xyzd50 ;
• Coordinates : x, y, z ;

XYZ-D65

• ColorSpace case: ColorSpace::XyzD65 ;
• Color class : matthieumastadenis\couleur\colors\XyzD65 ;
• Dedicated functions namespace : matthieumastadenis\couleur\utils\xyzD65 ;
• Accepted aliases : xyz-d65, xyz_d65, xyzd65, xyz ;
• Coordinates : x, y, z ;

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🤝 Contributing

You're welcome to contribute to this package by using issues and pull requests.

Before submitting any breaking change, please consider contacting me (either by directly submitting an issue, or by sending me a DM on Twitter if you really feel it's more appropriate).

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📜 License

Couleur is publicly shared under the MIT License. You can freely use it in any project. For more information, please read the included License File.

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❤️ Thanks

A huge thanks to Lea Verou and Chris Lilley for their incredible work and their precise articles on the subject. With a special thanks to Chris for the time and the answers he gave me during the implementation of this library.

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