wiki.techinc.nl/resources/jquery/jquery.colorUtil.js

/**
 * jQuery Color Utilities
 * Written by Krinkle in 2011
 * Released under the MIT and GPL licenses.
 * Mostly based on other plugins and functions (linted and optimized a little).
 * Sources cited inline.
 */
( function ( $ ) {
	$.colorUtil = {

		// Color Conversion function from highlightFade
		// By Blair Mitchelmore
		// http://jquery.offput.ca/highlightFade/
		// Parse strings looking for color tuples [255,255,255]
		getRGB: function ( color ) {
			/*jshint boss:true */
			var result;

			// Check if we're already dealing with an array of colors
			if ( color && $.isArray( color ) && color.length === 3 ) {
				return color;
			}

			// Look for rgb(num,num,num)
			if (result = /rgb\(\s*([0-9]{1,3})\s*,\s*([0-9]{1,3})\s*,\s*([0-9]{1,3})\s*\)/.exec(color)) {
				return [parseInt(result[1],10), parseInt(result[2],10), parseInt(result[3],10)];
			}

			// Look for rgb(num%,num%,num%)
			if (result = /rgb\(\s*([0-9]+(?:\.[0-9]+)?)\%\s*,\s*([0-9]+(?:\.[0-9]+)?)\%\s*,\s*([0-9]+(?:\.[0-9]+)?)\%\s*\)/.exec(color)) {
				return [parseFloat(result[1],10) * 2.55, parseFloat(result[2],10) * 2.55, parseFloat(result[3]) * 2.55];
			}

			// Look for #a0b1c2
			if (result = /#([a-fA-F0-9]{2})([a-fA-F0-9]{2})([a-fA-F0-9]{2})/.exec(color)) {
				return [parseInt(result[1],16), parseInt(result[2],16), parseInt(result[3],16)];
			}

			// Look for #fff
			if (result = /#([a-fA-F0-9])([a-fA-F0-9])([a-fA-F0-9])/.exec(color)) {
				return [parseInt(result[1] + result[1],16), parseInt(result[2] + result[2],16), parseInt(result[3] + result[3],16)];
			}

			// Look for rgba(0, 0, 0, 0) == transparent in Safari 3
			if (result = /rgba\(0, 0, 0, 0\)/.exec(color)) {
				return $.colorUtil.colors.transparent;
			}

			// Otherwise, we're most likely dealing with a named color
			return $.colorUtil.colors[$.trim(color).toLowerCase()];
		},

		// Some named colors to work with
		// From Interface by Stefan Petre
		// http://interface.eyecon.ro/
		colors: {
			aqua: [0,255,255],
			azure: [240,255,255],
			beige: [245,245,220],
			black: [0,0,0],
			blue: [0,0,255],
			brown: [165,42,42],
			cyan: [0,255,255],
			darkblue: [0,0,139],
			darkcyan: [0,139,139],
			darkgrey: [169,169,169],
			darkgreen: [0,100,0],
			darkkhaki: [189,183,107],
			darkmagenta: [139,0,139],
			darkolivegreen: [85,107,47],
			darkorange: [255,140,0],
			darkorchid: [153,50,204],
			darkred: [139,0,0],
			darksalmon: [233,150,122],
			darkviolet: [148,0,211],
			fuchsia: [255,0,255],
			gold: [255,215,0],
			green: [0,128,0],
			indigo: [75,0,130],
			khaki: [240,230,140],
			lightblue: [173,216,230],
			lightcyan: [224,255,255],
			lightgreen: [144,238,144],
			lightgrey: [211,211,211],
			lightpink: [255,182,193],
			lightyellow: [255,255,224],
			lime: [0,255,0],
			magenta: [255,0,255],
			maroon: [128,0,0],
			navy: [0,0,128],
			olive: [128,128,0],
			orange: [255,165,0],
			pink: [255,192,203],
			purple: [128,0,128],
			violet: [128,0,128],
			red: [255,0,0],
			silver: [192,192,192],
			white: [255,255,255],
			yellow: [255,255,0],
			transparent: [255,255,255]
		},

		/**
		 * http://mjijackson.com/2008/02/rgb-to-hsl-and-rgb-to-hsv-color-model-conversion-algorithms-in-javascript
		 * Converts an RGB color value to HSL. Conversion formula
		 * adapted from http://en.wikipedia.org/wiki/HSL_color_space.
		 * Assumes r, g, and b are contained in the set [0, 255] and
		 * returns h, s, and l in the set [0, 1].
		 *
		 * @param	Number	R		The red color value
		 * @param	Number	G		The green color value
		 * @param	Number	B		The blue color value
		 * @return	Array			The HSL representation
		 */
		rgbToHsl: function ( R, G, B ) {
			var d,
				r = R / 255,
				g = G / 255,
				b = B / 255,
				max = Math.max( r, g, b ), min = Math.min( r, g, b ),
				h,
				s,
				l = (max + min) / 2;

			if ( max === min ) {
				// achromatic
				h = s = 0;
			} else {
				d = max - min;
				s = l > 0.5 ? d / (2 - max - min) : d / (max + min);
				switch ( max ) {
					case r:
						h = (g - b) / d + (g < b ? 6 : 0);
						break;
					case g:
						h = (b - r) / d + 2;
						break;
					case b:
						h = (r - g) / d + 4;
						break;
				}
				h /= 6;
			}

			return [h, s, l];
		},

		/**
		 * http://mjijackson.com/2008/02/rgb-to-hsl-and-rgb-to-hsv-color-model-conversion-algorithms-in-javascript
		 * Converts an HSL color value to RGB. Conversion formula
		 * adapted from http://en.wikipedia.org/wiki/HSL_color_space.
		 * Assumes h, s, and l are contained in the set [0, 1] and
		 * returns r, g, and b in the set [0, 255].
		 *
		 * @param	Number	h		The hue
		 * @param	Number	s		The saturation
		 * @param	Number	l		The lightness
		 * @return	Array			The RGB representation
		 */
		hslToRgb: function ( h, s, l ) {
			var r, g, b, hue2rgb, q, p;

			if ( s === 0 ) {
				r = g = b = l; // achromatic
			} else {
				hue2rgb = function ( p, q, t ) {
					if ( t < 0 ) {
						t += 1;
					}
					if ( t > 1 ) {
						t -= 1;
					}
					if ( t < 1 / 6 ) {
						return p + (q - p) * 6 * t;
					}
					if ( t < 1 / 2 ) {
						return q;
					}
					if ( t < 2 / 3 ) {
						return p + (q - p) * (2 / 3 - t) * 6;
					}
					return p;
				};

				q = l < 0.5 ? l * (1 + s) : l + s - l * s;
				p = 2 * l - q;
				r = hue2rgb( p, q, h + 1 / 3 );
				g = hue2rgb( p, q, h );
				b = hue2rgb( p, q, h - 1 / 3 );
			}

			return [r * 255, g * 255, b * 255];
		},

		/**
		 * Get's a brighter or darker rgb() value string.
		 *
		 * @author Krinkle
		 *
		 * @example	getCSSColorMod( 'red', +0.1 )
		 * @example	getCSSColorMod( 'rgb(200,50,50)', -0.2 )
		 *
		 * @param	Mixed	currentColor current value in css
		 * @param	Number	mod wanted brightness modification between -1 and 1
		 * @return	String 'rgb(r,g,b)'
		 */
		getColorBrightness: function ( currentColor, mod ) {
			var rgbArr = $.colorUtil.getRGB( currentColor ),
				hslArr = $.colorUtil.rgbToHsl(rgbArr[0], rgbArr[1], rgbArr[2] );
			rgbArr = $.colorUtil.hslToRgb(hslArr[0], hslArr[1], hslArr[2] + mod);

			return 'rgb(' +
				[parseInt( rgbArr[0], 10), parseInt( rgbArr[1], 10 ), parseInt( rgbArr[2], 10 )].join( ',' ) +
				')';
		}

	};

}( jQuery ) );