Converting certain values back and forth is often necessary when developing functions to help your website work the way you want it to. I needed a function that would convert a hex color to rgb and for some reason it took me a while to figure it out.

function hex2rgb($hex) {

$hex = str_replace("#", "", $hex);

if(strlen($hex) == 3) {

$r = hexdec(substr($hex,0,1).substr($hex,0,1));

$g = hexdec(substr($hex,1,1).substr($hex,1,1));

$b = hexdec(substr($hex,2,1).substr($hex,2,1));

} else {

$r = hexdec(substr($hex,0,2));

$g = hexdec(substr($hex,2,2));

$b = hexdec(substr($hex,4,2));

}

$rgb = array($r, $g, $b);

//return implode(",", $rgb); // returns the rgb values separated by commas

return $rgb; // returns an array with the rgb values

}

This function works with both shorthand hex codes such as

**#f00** and longhand hex codes such as

**#ff0000**. It also accepts the number sign (#) just in case. You can see there are two return lines at the end of the function. The first, which is commented out, will return the rgb values separated by a comma. The second, which is the default, will return an array with the rgb values.

So now with this function in place we can use it like so:

$rgb = hex2rgb("#cc0");

print_r($rgb);

The above function would output:

Array ( [0] => 204 [1] => 204 [2] => 0 )

Since we are going one way with this, might as well go the other. Here is a function to convert rgb to a hex color:

function rgb2hex($rgb) {

$hex = "#";

$hex .= str_pad(dechex($rgb[0]), 2, "0", STR_PAD_LEFT);

$hex .= str_pad(dechex($rgb[1]), 2, "0", STR_PAD_LEFT);

$hex .= str_pad(dechex($rgb[2]), 2, "0", STR_PAD_LEFT);

return $hex; // returns the hex value including the number sign (#)

}

This function works like so:

$rgb = array( 255, 255, 255 );

$hex = rgb2hex($rgb);

echo $hex;

The above function would output:

#ffffff

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