Get opposite color text of any background color

<?php

function randomcolor()
{
    $myrandomcolor  = "#";
    for ($i=1; $i<=3; $i++)
        {
            $x = rand(0,255);
            $x = dechex($x);
            $x = strtoupper($x);
            if (strlen($x) == 1)
            {
                $x = "0".$x;
            }
            $myrandomcolor  .= $x;
        }
    return $myrandomcolor;
}

$color_backgr=randomcolor();
$nrcolor_backgr=preg_replace("/[^0-9,^A-Z]/","",$color_backgr);

$nrc=hexdec($nrcolor_backgr);
$r=$nrc >> 16 & 0xff;
$g=$nrc >> 8 & 0xff;
$b=$nrc & 0xff;

$rc=$r ^ 0xff;
$gc=$g ^ 0xff;
$bc=$b ^ 0xff;

$oppositeColor=( $rc << 16 ) | ( $gc << 8 ) | $bc;

$oppositeColor="#".substr("000000".dechex($oppositeColor),-6);

$color_text=$oppositeColor;

echo $color_text;

?>

Color text code: #b7e591
Color background code: #481A6E
Example: Test