How do I fix Hex to RGB in PHP 8.0+?

I've had this code working for some time that i pulled from somewhere on the net, probably here. It converts Hex Code to RGB to make a gradient on a GD image. I upgraded my server to PHP 8.1 from 7.4 and not it never produces and image and will just infinitely load with thousands or more "Depricated" Float errors like:

Deprecated: Implicit conversion from float 45.99999999999999 to int loses precision

Original Hex2RGB code:

// Functions
function gradient($w=100, $h=100, $c=array('#FFFFFF','#FF0000','#00FF00','#0000FF'), $hex=true) {

$blockbg = imagecreatetruecolor($w,$h);

if($hex) {  // convert hex-values to rgb
  for($i=0;$i<=3;$i++) {
   $c[$i]=hex2rgb($c[$i]);
  }
}

$rgb=$c[0]; // start with top left color
for($x=0;$x<=$w;$x++) { // loop columns
  for($y=0;$y<=$h;$y++) { // loop rows
   // set pixel color
   $col=imagecolorallocate($blockbg,$rgb[0],$rgb[1],$rgb[2]);
   imagesetpixel($blockbg,$x-1,$y-1,$col);
   // calculate new color 
   for($i=0;$i<=2;$i++) {
    $rgb[$i]=
      $c[0][$i]*(($w-$x)*($h-$y)/($w*$h)) +
      $c[1][$i]*($x     *($h-$y)/($w*$h)) +
      $c[2][$i]*(($w-$x)*$y     /($w*$h)) +
      $c[3][$i]*($x     *$y     /($w*$h));
   }
  }
}
return $blockbg;
}

function hex2rgb($hex)
{
$rgb[0]=hexdec(substr($hex,1,2));
$rgb[1]=hexdec(substr($hex,3,2));
$rgb[2]=hexdec(substr($hex,5,2));
return($rgb);
}
////////////////////

//*----- Hex to RGB for Number and Font Color conversion -----*//
function hex2rgb2($hex2) {
    $hex2 = str_replace('#', '', $hex2);

     if(strlen($hex2) == 3) {
      $r = hexdec(substr($hex2,0,1).substr($hex2,0,1));
      $g = hexdec(substr($hex2,1,1).substr($hex2,1,1));
      $b = hexdec(substr($hex2,2,1).substr($hex2,2,1));
    } else {
      $r = hexdec(substr($hex2,0,2));
      $g = hexdec(substr($hex2,2,2));
      $b = hexdec(substr($hex2,4,2));
    }
    return array($r, $g, $b); // RETURN ARRAY INSTEAD OF STRING
}

Any help is appreciated. I had a whole image system and now it's completely broken.

I keep getting the error specially on this line. I already know float is deprecated, which is why I'm here and I can't seem to find the place to put a 'round' or 'intval'.

$col=imagecolorallocate($blockbg,$rgb[0],$rgb[1],$rgb[2]);