phpColors w/percent to white or black

gistfile1.txt

<?php

/**
 * Author: Arlo Carreon <http://arlocarreon.com>
 * Info: http://mexitek.github.io/phpColors/
 * License: http://arlo.mit-license.org/
 */

namespace Mexitek\PHPColors;

use \Exception;

/**
 * A color utility that helps manipulate HEX colors
 */
class Color{

	private $_hex;
	private $_hsl;
	private $_rgb;

	/**
	 * Auto darkens/lightens by 10% for sexily-subtle gradients.
	 * Set this to FALSE to adjust automatic shade to be between given color
	 * and black (for darken) or white (for lighten)
	 */
	const DEFAULT_ADJUST = 10;

	/**
	 * Instantiates the class with a HEX value
	 *
	 * @param string $hex
	 *
	 * @throws Exception "Bad color format"
	 */
	function __construct($hex){
		// Strip # sign is present
		$color = str_replace("#", "", $hex);

		// Make sure it's 6 digits
		if(strlen($color) === 3){
			$color = $color[0] . $color[0] . $color[1] . $color[1] . $color[2] . $color[2];
		}else if(strlen($color) != 6){
			throw new Exception("HEX color needs to be 6 or 3 digits long");
		}

		$this->_hsl = self::hexToHsl($color);
		$this->_hex = $color;
		$this->_rgb = self::hexToRgb($color);
	}

	// ====================
	// = Public Interface =
	// ====================

	/**
	 * Given a HEX string returns a HSL array equivalent.
	 *
	 * @param string $color
	 *
	 * @return array HSL associative array
	 */
	public static function hexToHsl($color){

		// Sanity check
		$color = self::_checkHex($color);

		// Convert HEX to DEC
		$R = hexdec($color[0] . $color[1]);
		$G = hexdec($color[2] . $color[3]);
		$B = hexdec($color[4] . $color[5]);

		$HSL = array();

		$var_R = ($R / 255);
		$var_G = ($G / 255);
		$var_B = ($B / 255);

		$var_Min = min($var_R, $var_G, $var_B);
		$var_Max = max($var_R, $var_G, $var_B);
		$del_Max = $var_Max - $var_Min;

		$L = ($var_Max + $var_Min) / 2;

		if($del_Max == 0){
			$H = 0;
			$S = 0;
		}else{
			if($L < 0.5){
				$S = $del_Max / ($var_Max + $var_Min);
			}else{
				$S = $del_Max / (2 - $var_Max - $var_Min);
			}

			$del_R = ((($var_Max - $var_R) / 6) + ($del_Max / 2)) / $del_Max;
			$del_G = ((($var_Max - $var_G) / 6) + ($del_Max / 2)) / $del_Max;
			$del_B = ((($var_Max - $var_B) / 6) + ($del_Max / 2)) / $del_Max;

			if($var_R == $var_Max){
				$H = $del_B - $del_G;
			}else if($var_G == $var_Max){
				$H = (1 / 3) + $del_R - $del_B;
			}else if($var_B == $var_Max){
				$H = (2 / 3) + $del_G - $del_R;
			}

			if($H < 0){
				$H ++;
			}
			if($H > 1){
				$H --;
			}
		}

		$HSL['H'] = ($H * 360);
		$HSL['S'] = $S;
		$HSL['L'] = $L;

		return $HSL;
	}

	/**
	 *  Given a HSL associative array returns the equivalent HEX string
	 *
	 * @param array $hsl
	 *
	 * @return string HEX string
	 * @throws Exception "Bad HSL Array"
	 */
	public static function hslToHex($hsl = array()){
		// Make sure it's HSL
		if(empty($hsl) || !isset($hsl["H"]) || !isset($hsl["S"]) || !isset($hsl["L"])){
			throw new Exception("Param was not an HSL array");
		}

		list($H, $S, $L) = array($hsl['H'] / 360, $hsl['S'], $hsl['L']);

		if($S == 0){
			$r = $L * 255;
			$g = $L * 255;
			$b = $L * 255;
		}else{

			if($L < 0.5){
				$var_2 = $L * (1 + $S);
			}else{
				$var_2 = ($L + $S) - ($S * $L);
			}

			$var_1 = 2 * $L - $var_2;

			$r = round(255 * self::_huetorgb($var_1, $var_2, $H + (1 / 3)));
			$g = round(255 * self::_huetorgb($var_1, $var_2, $H));
			$b = round(255 * self::_huetorgb($var_1, $var_2, $H - (1 / 3)));

		}

		// Convert to hex
		$r = dechex($r);
		$g = dechex($g);
		$b = dechex($b);

		// Make sure we get 2 digits for decimals
		$r = (strlen("" . $r) === 1) ? "0" . $r : $r;
		$g = (strlen("" . $g) === 1) ? "0" . $g : $g;
		$b = (strlen("" . $b) === 1) ? "0" . $b : $b;

		return $r . $g . $b;
	}


	/**
	 * Given a HEX string returns a RGB array equivalent.
	 *
	 * @param string $color
	 *
	 * @return array RGB associative array
	 */
	public static function hexToRgb($color){

		// Sanity check
		$color = self::_checkHex($color);

		// Convert HEX to DEC
		$R = hexdec($color[0] . $color[1]);
		$G = hexdec($color[2] . $color[3]);
		$B = hexdec($color[4] . $color[5]);

		$RGB['R'] = $R;
		$RGB['G'] = $G;
		$RGB['B'] = $B;

		return $RGB;
	}


	/**
	 *  Given an RGB associative array returns the equivalent HEX string
	 *
	 * @param array $rgb
	 *
	 * @return string RGB string
	 * @throws Exception "Bad RGB Array"
	 */
	public static function rgbToHex($rgb = array()){
		// Make sure it's RGB
		if(empty($rgb) || !isset($rgb["R"]) || !isset($rgb["G"]) || !isset($rgb["B"])){
			throw new Exception("Param was not an RGB array");
		}

		// Convert RGB to HEX
		$hex[0] = dechex($rgb['R']);
		$hex[1] = dechex($rgb['G']);
		$hex[2] = dechex($rgb['B']);

		return implode('', $hex);

	}


	/**
	 * Given a HEX value, returns a darker color. If no desired amount provided, then the color halfway between
	 * given HEX and black will be returned.
	 *
	 * @param int $amount
	 *
	 * @return string Darker HEX value
	 */
	public function darken($amount = self::DEFAULT_ADJUST, $percent_to_black = true){
		// Darken
		$darkerHSL = $this->_darken($this->_hsl, $amount, $percent_to_black);

		// Return as HEX
		return self::hslToHex($darkerHSL);
	}


	/**
	 * Given a HEX value, returns a lighter color. If no desired amount provided, then the color halfway between
	 * given HEX and white will be returned.
	 *
	 * @param int $amount
	 *
	 * @return string Lighter HEX value
	 */
	public function lighten($amount = self::DEFAULT_ADJUST, $percent_to_white = true){
		// Lighten
		$lighterHSL = $this->_lighten($this->_hsl, $amount, $percent_to_white);

		// Return as HEX
		return self::hslToHex($lighterHSL);
	}

	/**
	 * Given a HEX value, returns a mixed color. If no desired amount provided, then the color mixed by this ratio
	 *
	 * @param string $hex2   Secondary HEX value to mix with
	 * @param int    $amount = -100..0..+100
	 *
	 * @return string mixed HEX value
	 */
	public function mix($hex2, $amount = 0){
		$rgb2 = self::hexToRgb($hex2);
		$mixed = $this->_mix($this->_rgb, $rgb2, $amount);

		// Return as HEX
		return self::rgbToHex($mixed);
	}

	/**
	 * Creates an array with two shades that can be used to make a gradient
	 *
	 * @param int $amount Optional percentage amount you want your contrast color
	 *
	 * @return array An array with a 'light' and 'dark' index
	 */
	public function makeGradient($amount = self::DEFAULT_ADJUST){
		// Decide which color needs to be made
		if($this->isLight()){
			$lightColor = $this->_hex;
			$darkColor = $this->darken($amount);
		}else{
			$lightColor = $this->lighten($amount);
			$darkColor = $this->_hex;
		}

		// Return our gradient array
		return array("light" => $lightColor, "dark" => $darkColor);
	}


	/**
	 * Returns whether or not given color is considered "light"
	 *
	 * @param string|Boolean $color
	 *
	 * @return boolean
	 */
	public function isLight($color = false){
		// Get our color
		$color = ($color) ? $color : $this->_hex;

		// Calculate straight from rbg
		$r = hexdec($color[0] . $color[1]);
		$g = hexdec($color[2] . $color[3]);
		$b = hexdec($color[4] . $color[5]);

		return (($r * 299 + $g * 587 + $b * 114) / 1000 > 130);
	}

	/**
	 * Returns whether or not a given color is considered "dark"
	 *
	 * @param string|Boolean $color
	 *
	 * @return boolean
	 */
	public function isDark($color = false){
		// Get our color
		$color = ($color) ? $color : $this->_hex;

		// Calculate straight from rbg
		$r = hexdec($color[0] . $color[1]);
		$g = hexdec($color[2] . $color[3]);
		$b = hexdec($color[4] . $color[5]);

		return (($r * 299 + $g * 587 + $b * 114) / 1000 <= 130);
	}

	/**
	 * Returns the complimentary color
	 *
	 * @return string Complementary hex color
	 *
	 */
	public function complementary(){
		// Get our HSL
		$hsl = $this->_hsl;

		// Adjust Hue 180 degrees
		$hsl['H'] += ($hsl['H'] > 180) ? - 180 : 180;

		// Return the new value in HEX
		return self::hslToHex($hsl);
	}

	/**
	 * Returns your color's HSL array
	 */
	public function getHsl(){
		return $this->_hsl;
	}

	/**
	 * Returns your original color
	 */
	public function getHex(){
		return $this->_hex;
	}

	/**
	 * Returns your color's RGB array
	 */
	public function getRgb(){
		return $this->_rgb;
	}

	/**
	 * Returns the cross browser CSS3 gradient
	 *
	 * @param int     $amount          Optional: percentage amount to light/darken the gradient
	 * @param boolean $vintageBrowsers Optional: include vendor prefixes for browsers that almost died out already
	 * @param string  $prefix          Optional: prefix for every lines
	 * @param string  $suffix          Optional: suffix for every lines
	 *
	 * @link  http://caniuse.com/css-gradients Resource for the browser support
	 * @return string CSS3 gradient for chrome, safari, firefox, opera and IE10
	 */
	public function getCssGradient($amount = self::DEFAULT_ADJUST, $vintageBrowsers = false, $suffix = "", $prefix = ""){

		// Get the recommended gradient
		$g = $this->makeGradient($amount);

		$css = "";
		/* fallback/image non-cover color */
		$css .= "{$prefix}background-color: #" . $this->_hex . ";{$suffix}";

		/* IE Browsers */
		$css .= "{$prefix}filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#" . $g['light'] . "', endColorstr='#" . $g['dark'] . "');{$suffix}";

		/* Safari 4+, Chrome 1-9 */
		if($vintageBrowsers){
			$css .= "{$prefix}background-image: -webkit-gradient(linear, 0% 0%, 0% 100%, from(#" . $g['light'] . "), to(#" . $g['dark'] . "));{$suffix}";
		}

		/* Safari 5.1+, Mobile Safari, Chrome 10+ */
		$css .= "{$prefix}background-image: -webkit-linear-gradient(top, #" . $g['light'] . ", #" . $g['dark'] . ");{$suffix}";

		/* Firefox 3.6+ */
		if($vintageBrowsers){
			$css .= "{$prefix}background-image: -moz-linear-gradient(top, #" . $g['light'] . ", #" . $g['dark'] . ");{$suffix}";
		}

		/* Opera 11.10+ */
		if($vintageBrowsers){
			$css .= "{$prefix}background-image: -o-linear-gradient(top, #" . $g['light'] . ", #" . $g['dark'] . ");{$suffix}";
		}

		/* Unprefixed version (standards): FF 16+, IE10+, Chrome 26+, Safari 7+, Opera 12.1+ */
		$css .= "{$prefix}background-image: linear-gradient(to bottom, #" . $g['light'] . ", #" . $g['dark'] . ");{$suffix}";

		// Return our CSS
		return $css;
	}

	// ===========================
	// = Private Functions Below =
	// ===========================


	/**
	 * Darkens a given HSL array
	 *
	 * @param array $hsl
	 * @param int   $amount
	 *
	 * @return array $hsl
	 */

	private function _darken($hsl, $amount = self::DEFAULT_ADJUST, $percent_to_black){
		// Check if we were provided a number and want to adjust by percentage to complete black (100%).
		// 0 being original color and 100 being black.
		if($amount || $amount === 0 && $percent_to_black){
			$hsl['L'] -= $hsl['L'] / 100 * max(min($amount, 100), 0);//make sure amount is set between 0-100
		}elseif($amount){
			//$amount is percent lighter then its color with no relation to black.
			$hsl['L'] = ($hsl['L'] * 100) - $amount;
			$hsl['L'] = ($hsl['L'] < 0) ? 0 : $hsl['L'] / 100;
		}else{
			// We need to find out how much to darken
			$hsl['L'] = $hsl['L'] / 2;
		}

		return $hsl;
	}

	/**
	 * Lightens a given HSL array
	 *
	 * @param array $hsl
	 * @param int   $amount
	 *
	 * @return array $hsl
	 */
	private function _lighten($hsl, $amount = self::DEFAULT_ADJUST, $percent_to_white){

		// Check if we were provided a number and want to adjust by percentage to complete white (100%).
		// 0 being original color and 100 being white.
		if($amount || $amount === 0 && $percent_to_white){
			$hsl['L'] += (1 - $hsl['L']) / 100 * max(min($amount, 100), 0);//make sure amount is set between 0-100
		}elseif($amount){
			//$amount is percent lighter then its color with no relation to white.
			$hsl['L'] = ($hsl['L'] * 100) + $amount;
			$hsl['L'] = ($hsl['L'] > 100) ? 1 : $hsl['L'] / 100;
		}else{
			// We need to find out how much to lighten
			$hsl['L'] += (1 - $hsl['L']) / 2;
		}

		return $hsl;
	}

	/**
	 * Mix 2 rgb colors and return an rgb color
	 *
	 * @param array $rgb1
	 * @param array $rgb2
	 * @param int   $amount ranged -100..0..+100
	 *
	 * @return array $rgb
	 *
	 *    ported from http://phpxref.pagelines.com/nav.html?includes/class.colors.php.source.html
	 */
	private function _mix($rgb1, $rgb2, $amount = 0){

		$r1 = ($amount + 100) / 100;
		$r2 = 2 - $r1;

		$rmix = (($rgb1['R'] * $r1) + ($rgb2['R'] * $r2)) / 2;
		$gmix = (($rgb1['G'] * $r1) + ($rgb2['G'] * $r2)) / 2;
		$bmix = (($rgb1['B'] * $r1) + ($rgb2['B'] * $r2)) / 2;

		return array('R' => $rmix, 'G' => $gmix, 'B' => $bmix);
	}

	/**
	 * Given a Hue, returns corresponding RGB value
	 *
	 * @param int $v1
	 * @param int $v2
	 * @param int $vH
	 *
	 * @return int
	 */
	private static function _huetorgb($v1, $v2, $vH){
		if($vH < 0){
			$vH += 1;
		}

		if($vH > 1){
			$vH -= 1;
		}

		if((6 * $vH) < 1){
			return ($v1 + ($v2 - $v1) * 6 * $vH);
		}

		if((2 * $vH) < 1){
			return $v2;
		}

		if((3 * $vH) < 2){
			return ($v1 + ($v2 - $v1) * ((2 / 3) - $vH) * 6);
		}

		return $v1;

	}

	/**
	 * You need to check if you were given a good hex string
	 *
	 * @param string $hex
	 *
	 * @return string Color
	 * @throws Exception "Bad color format"
	 */
	private static function _checkHex($hex){
		// Strip # sign is present
		$color = str_replace("#", "", $hex);

		// Make sure it's 6 digits
		if(strlen($color) == 3){
			$color = $color[0] . $color[0] . $color[1] . $color[1] . $color[2] . $color[2];
		}else if(strlen($color) != 6){
			throw new Exception("HEX color needs to be 6 or 3 digits long");
		}

		return $color;
	}

}