- bin2hex: documentation ( source)
- pack: documentation ( source)
- str_split: documentation ( source)
<?php
$color = str_split('0F000000', 2);
$w = 1;
$h = 1;
$r = $color[0];
$g = $color[1];
$b = $color[2];
$a = $color[3];
$packed = pack("V2C4", $w, $h, $r, $g, $b, $a);
print bin2hex($packed);