codenothing/random-color-generator.html

## random-color-generator.html
<html>
	<head>
		<title>Random Color Generator</title>
		<script type='text/javascript' src='http://ajax.googleapis.com/ajax/libs/jquery/1.3.2/jquery.min.js'></script>
		<script type='text/javascript' src='Color.js'></script>
		<script type='text/javascript'>
			// Used jQuery because it's just easier that way
			jQuery(function($){
				var $tbody = $('tbody');
				// Creating Color
				$('#generate').click(function(){
					var hex = Color.random(),
						rgb = Color.hex2rgb(hex),
						html = $tbody.html(),
						row = [
							"<tr>",
								"<td class='block' bgcolor='"+hex+"'>&nbsp;</td>",
								"<td>"+hex+"</td>",
								"<td>"+rgb.join(',')+"</td>",
							"</tr>"
						].join('');

					$tbody.html( row + html );
				});
				$('#reset').click(function(){
					Color.reset();
					$tbody.html('');
				});
			});
		</script>
		<style type='text/css'>
			body { font-size: 10pt; }
			table { width: 400px; border: 2px solid black; margin: 5px 3px; }
			th {text-align: left;}
			td.block { border: 2px solid #989898; }
		</style>
	</head>
	<body>


		<!--
		Random Color Generator
		December 28, 2009
		Corey Hart @ http://www.codenothing.com
		-->


		<h1>Random Color Generator</h1>
		<button id="generate">Generate</button>
		<button id="reset">Reset</button>
		<table cellpadding='3' cellspacing='2'>
			<thead>
				<tr>
					<th width='30'>Color</th>
					<th>Hex</th>
					<th>RGB</th>
				</tr>
			</thead>
			<tbody></tbody>
		</table>
	</body>
</html>

## random-color-generator.js
/*!
 * Random Color Generator
 * December 28, 2009
 * Corey Hart @ http://www.codenothing.com
 */
var Color = {
	defaults: {
		// Predefined hex codes that cant be used as random colors
		// All must be prefixed with the '#' indicator
		predef: [],

		// Maximum & Minimum random range values
		rangeMax: 255,
		rangeMin: 0,

		// Upper and lower level values that must be
		// passed for random color acceptance
		//
		// By setting levelUp: 200, levelDown: 100; Neutral
		// colors like White, Gray, and Black can be somewhat weeded
		// out and your random colors will be full spectrum based.
		// Note*: Doing so increases likely hood of recursion
		levelUp: -1,
		levelDown: 256,

		// Recursion handlers
		recursionLimit: 15,
		recursion: function(){
			throw 'Recursion Error in Random Color Generator, ' +
				'too many tries on finding random color, ' +
				'[Limit ' + this.recursionLimit + ']';
		}
	},

	// Caching of random colors
	stack: {},

	// Returns a random color in hex code form, and caches
	// find in the stack.
	random: function(i){
		var self = this,
			defaults = self.defaults,
			r = self.rand(),
			g = self.rand(),
			b = self.rand(),
			hex = self.rgb2hex(r, g, b),
			levels = true;

		// Check for recursion
		if (i === undefined || typeof i !== 'number') i = 0;
		else if (i++ > defaults.recursionLimit) return defaults.recursion();

		// Color already used, try another one
		if (self.stack[hex]) hex = self.random(i);

		// Ensure one of the vals is above levelUp and another is below levelDown
		// Check defaults comments for better understanding
		levels = !!(
			(r > defaults.levelUp || g > defaults.levelUp || b > defaults.levelUp) &&
			(r < defaults.levelDown || g < defaults.levelDown || b < defaults.levelDown)
		);
		if (! levels) hex = self.random(i);

		// Store on stack to help prevent repeat
		self.stack[hex] = [r,g,b];

		// Return hex code in #
		return hex;
	},

	// Returns random number within range
	rand: function(){
		var defaults = this.defaults;
		return defaults.rangeMin + Math.floor(Math.random()*(defaults.rangeMax+1));
	},

	// Clears the stack
	reset: function(){
		var self = this,
			predef = self.defaults.predef,
			i = -1, l = predef.length;
		self.stack = {};
		if (l > 0)
			for ( ; ++i < l; )
				self.stack[ predef[i] ] = true;
	},

	// Returns hex code
	rgb2hex: function(r, g, b){
		var str = '0123456789ABCDEF';
		return '#' + [
			str.charAt((r-r%16)/16) + str.charAt(r%16),
			str.charAt((g-g%16)/16) + str.charAt(g%16),
			str.charAt((b-b%16)/16) + str.charAt(b%16)
		].join('');
	},

	// Returns in array form [red, green, blue]
	hex2rgb: function(hex){
		if (hex.substr(0, 1) === '#')
			hex = hex.substr(1);

		// Use the stack if possible to reduce processing
		return this.stack['#'+hex] ? this.stack['#'+hex] :
			hex.length === 6 ? [
				parseInt(hex.substr(0, 2), 16),
				parseInt(hex.substr(2, 2), 16),
				parseInt(hex.substr(4, 2), 16)
			] : hex.length === 3 ? [
				parseInt(hex.substr(0, 1), 16),
				parseInt(hex.substr(1, 1), 16),
				parseInt(hex.substr(2, 1), 16)
			] : [];
	}
};
	<html>
	<head>
	<title>Random Color Generator</title>
	<script type='text/javascript' src='http://ajax.googleapis.com/ajax/libs/jquery/1.3.2/jquery.min.js'></script>
	<script type='text/javascript' src='Color.js'></script>
	<script type='text/javascript'>
	// Used jQuery because it's just easier that way
	jQuery(function($){
	var $tbody = $('tbody');
	// Creating Color
	$('#generate').click(function(){
	var hex = Color.random(),
	rgb = Color.hex2rgb(hex),
	html = $tbody.html(),
	row = [
	"<tr>",
	"<td class='block' bgcolor='"+hex+"'> </td>",
	"<td>"+hex+"</td>",
	"<td>"+rgb.join(',')+"</td>",
	"</tr>"
	].join('');

	$tbody.html( row + html );
	});
	$('#reset').click(function(){
	Color.reset();
	$tbody.html('');
	});
	});
	</script>
	<style type='text/css'>
	body { font-size: 10pt; }
	table { width: 400px; border: 2px solid black; margin: 5px 3px; }
	th {text-align: left;}
	td.block { border: 2px solid #989898; }
	</style>
	</head>
	<body>


	<!--
	Random Color Generator
	December 28, 2009
	Corey Hart @ http://www.codenothing.com
	-->


	<h1>Random Color Generator</h1>
	<button id="generate">Generate</button>
	<button id="reset">Reset</button>
	<table cellpadding='3' cellspacing='2'>
	<thead>
	<tr>
	<th width='30'>Color</th>
	<th>Hex</th>
	<th>RGB</th>
	</tr>
	</thead>
	<tbody></tbody>
	</table>
	</body>
	</html>
	/*!
	* Random Color Generator
	* December 28, 2009
	* Corey Hart @ http://www.codenothing.com
	*/
	var Color = {
	defaults: {
	// Predefined hex codes that cant be used as random colors
	// All must be prefixed with the '#' indicator
	predef: [],

	// Maximum & Minimum random range values
	rangeMax: 255,
	rangeMin: 0,

	// Upper and lower level values that must be
	// passed for random color acceptance
	//
	// By setting levelUp: 200, levelDown: 100; Neutral
	// colors like White, Gray, and Black can be somewhat weeded
	// out and your random colors will be full spectrum based.
	// Note*: Doing so increases likely hood of recursion
	levelUp: -1,
	levelDown: 256,

	// Recursion handlers
	recursionLimit: 15,
	recursion: function(){
	throw 'Recursion Error in Random Color Generator, ' +
	'too many tries on finding random color, ' +
	'[Limit ' + this.recursionLimit + ']';
	}
	},

	// Caching of random colors
	stack: {},

	// Returns a random color in hex code form, and caches
	// find in the stack.
	random: function(i){
	var self = this,
	defaults = self.defaults,
	r = self.rand(),
	g = self.rand(),
	b = self.rand(),
	hex = self.rgb2hex(r, g, b),
	levels = true;

	// Check for recursion
	if (i === undefined \|\| typeof i !== 'number') i = 0;
	else if (i++ > defaults.recursionLimit) return defaults.recursion();

	// Color already used, try another one
	if (self.stack[hex]) hex = self.random(i);

	// Ensure one of the vals is above levelUp and another is below levelDown
	// Check defaults comments for better understanding
	levels = !!(
	(r > defaults.levelUp \|\| g > defaults.levelUp \|\| b > defaults.levelUp) &&
	(r < defaults.levelDown \|\| g < defaults.levelDown \|\| b < defaults.levelDown)
	);
	if (! levels) hex = self.random(i);

	// Store on stack to help prevent repeat
	self.stack[hex] = [r,g,b];

	// Return hex code in #
	return hex;
	},

	// Returns random number within range
	rand: function(){
	var defaults = this.defaults;
	return defaults.rangeMin + Math.floor(Math.random()*(defaults.rangeMax+1));
	},

	// Clears the stack
	reset: function(){
	var self = this,
	predef = self.defaults.predef,
	i = -1, l = predef.length;
	self.stack = {};
	if (l > 0)
	for ( ; ++i < l; )
	self.stack[ predef[i] ] = true;
	},

	// Returns hex code
	rgb2hex: function(r, g, b){
	var str = '0123456789ABCDEF';
	return '#' + [
	str.charAt((r-r%16)/16) + str.charAt(r%16),
	str.charAt((g-g%16)/16) + str.charAt(g%16),
	str.charAt((b-b%16)/16) + str.charAt(b%16)
	].join('');
	},

	// Returns in array form [red, green, blue]
	hex2rgb: function(hex){
	if (hex.substr(0, 1) === '#')
	hex = hex.substr(1);

	// Use the stack if possible to reduce processing
	return this.stack['#'+hex] ? this.stack['#'+hex] :
	hex.length === 6 ? [
	parseInt(hex.substr(0, 2), 16),
	parseInt(hex.substr(2, 2), 16),
	parseInt(hex.substr(4, 2), 16)
	] : hex.length === 3 ? [
	parseInt(hex.substr(0, 1), 16),
	parseInt(hex.substr(1, 1), 16),
	parseInt(hex.substr(2, 1), 16)
	] : [];
	}
	};