gido/blackify hex color

## blackify hex color
<?php

$input = "#A2D73A";
if(!preg_match('/#([0-9A-Fa-f]{2})([0-9A-Fa-f]{2})([0-9A-Fa-f]{2})/', $input, $matches)){
  die(sprintf("Error: '%s' is not a valid hexadecimal color!", $input));
}


$bgColor1 = $input;
$bgColor2 = blackify($input, 60);
$bgColor3 = blackify($input, 100);
$bgColor4 = blackify($input, 150);

/**
 * Reduce red, green and blue color
 *
 * @param string $hexaString (format: #FFAA33)
 * @param integer $increment
 */
function blackify($hexaString, $inc) {
  if(!preg_match('/#([0-9A-Fa-f]{2})([0-9A-Fa-f]{2})([0-9A-Fa-f]{2})/', $hexaString, $matches)){
    return false;
  }

  list(, $red, $green, $blue) = $matches;

  $red   = intval($red, 16);
  $green = intval($green, 16);
  $blue  = intval($blue, 16);

  $red2   = ($red - $inc);
  $green2 = ($green - $inc);
  $blue2  = ($blue - $inc);

  // keept value in range 0..255
  $red2   = $red2 > 255 ? 255 : ($red2 < 0 ? 0 : $red2);
  $green2 = $green2 > 255 ? 255 : ($green2 < 0 ? 0 : $green2);
  $blue2  = $blue2 > 255 ? 255 : ($blue2 < 0 ? 0 : $blue2);


  return sprintf("#%02x%02x%02x", $red2, $green2, $blue2);
}

?><!doctype html>
<html lang="en" class="no-js">
<head>
  <meta charset="utf-8">
  <title>hexa color test</title>
  <meta name="description" content="">
  <meta name="author" content="Gilles Doge">

  <style type="text/css" media="screen">
    .block{
      display: block;
      float: left;
      height: 150px;
      width: 150px;
      border: 1px solid #f0f0f0;
      margin: 50px 50px 10px 20px;
      text-align: center;
      padding: 20px;
    }
  </style>
</head>
<body>
  <div id="container">

    <div id="main">
       <div id="block1" class="block" style="background-color: <?php echo $bgColor1; ?>">block 1</div>
       <div id="block2" class="block" style="background-color: <?php echo $bgColor2; ?>">block 2</div>
       <div id="block3" class="block" style="background-color: <?php echo $bgColor3; ?>">block 3</div>
       <div id="block4" class="block" style="background-color: <?php echo $bgColor4; ?>">block 4</div>

    </div>

  </div>
</body>
</html>
	<?php

	$input = "#A2D73A";
	if(!preg_match('/#([0-9A-Fa-f]{2})([0-9A-Fa-f]{2})([0-9A-Fa-f]{2})/', $input, $matches)){
	die(sprintf("Error: '%s' is not a valid hexadecimal color!", $input));
	}


	$bgColor1 = $input;
	$bgColor2 = blackify($input, 60);
	$bgColor3 = blackify($input, 100);
	$bgColor4 = blackify($input, 150);

	/**
	* Reduce red, green and blue color
	*
	* @param string $hexaString (format: #FFAA33)
	* @param integer $increment
	*/
	function blackify($hexaString, $inc) {
	if(!preg_match('/#([0-9A-Fa-f]{2})([0-9A-Fa-f]{2})([0-9A-Fa-f]{2})/', $hexaString, $matches)){
	return false;
	}

	list(, $red, $green, $blue) = $matches;

	$red = intval($red, 16);
	$green = intval($green, 16);
	$blue = intval($blue, 16);

	$red2 = ($red - $inc);
	$green2 = ($green - $inc);
	$blue2 = ($blue - $inc);

	// keept value in range 0..255
	$red2 = $red2 > 255 ? 255 : ($red2 < 0 ? 0 : $red2);
	$green2 = $green2 > 255 ? 255 : ($green2 < 0 ? 0 : $green2);
	$blue2 = $blue2 > 255 ? 255 : ($blue2 < 0 ? 0 : $blue2);


	return sprintf("#%02x%02x%02x", $red2, $green2, $blue2);
	}

	?><!doctype html>
	<html lang="en" class="no-js">
	<head>
	<meta charset="utf-8">
	<title>hexa color test</title>
	<meta name="description" content="">
	<meta name="author" content="Gilles Doge">

	<style type="text/css" media="screen">
	.block{
	display: block;
	float: left;
	height: 150px;
	width: 150px;
	border: 1px solid #f0f0f0;
	margin: 50px 50px 10px 20px;
	text-align: center;
	padding: 20px;
	}
	</style>
	</head>
	<body>
	<div id="container">

	<div id="main">
	<div id="block1" class="block" style="background-color: <?php echo $bgColor1; ?>">block 1</div>
	<div id="block2" class="block" style="background-color: <?php echo $bgColor2; ?>">block 2</div>
	<div id="block3" class="block" style="background-color: <?php echo $bgColor3; ?>">block 3</div>
	<div id="block4" class="block" style="background-color: <?php echo $bgColor4; ?>">block 4</div>

	</div>

	</div>
	</body>
	</html>