PHP allocate color without image resource

Question

Can you allocate a color in PHP GD without an image resource? It should be possible because really an allocated color is a number, right?

$im = imagecreatet         


        

Answer 1

Use this function

function img_color($r, $g, $b, $a=0) {
  // prepare red color
  if (is_string($r)) {
    if (!preg_match('/^[a-f0-9]{1,2}$/i', $r)) return false;
    $r = hexdec($r);
  }
  elseif (is_int($r)) {if ($r<0 or $r>255) return false;}
  else return false;

  // prepare green color
  if (is_string($g)) {
    if (!preg_match('/^[a-f0-9]{1,2}$/i', $g)) return false;
    $g = hexdec($g);
  }
  elseif (is_int($g)) {if ($g<0 or $g>255) return false;}
  else return false;

  // prepare blue color
  if (is_string($b)) {
    if (!preg_match('/^[a-f0-9]{1,2}$/i', $b)) return false;
    $b = hexdec($b);
  }
  elseif (is_int($b)) {if ($b<0 or $b>255) return false;}
  else return false;

  // prepare alpha channel
  if (is_string($a)) {
    if (!preg_match('/^[a-f0-9]{1,2}$/i', $a)) return false;
    $a = hexdec($a);
  }
  elseif (!is_int($a)) return false;
  if ($a<0 or $a>127) return false;

  $result = unpack('I', chr($b) . chr($g) . chr($r) . chr($a));
  return $result[1];
}