Borders for signwriter

Forgot the HTML code for the illustrations :)
Before:

After:

I'm doing a CVS update to 6-2 after a long period of inactivity and found a local patch I'd made but hadn't given back.
This is an improvement on the patch I gave above, providing softer corners and the ability to set borders greater that 1px that don't get chunky immediately. It's a better algorithm - suitable for bigger text.
Is much more processor-intensive as it does multiple redraws to do proper border radiuses.

posting raw code here for posterity and reference only - I'll see if it's worth patching in to the current release after I do a clean update, my local code has branched far.

/**
 * Slightly less crude way of getting a bordered effect
 */
function signwriter_bordered_text($im, $fontsize, $angle, $x, $y, $text_color, $fontfile, $line, $border_radius = 0, $border_color = 0) {
  if ($border_radius) {
    // Write a copy of the text - in all directions - including diagonals - and all pixels in between.
    // This method is scale-safe. You can add thick borders to thin text.
    // It scales exponentially however. radius 5 =~ 13 redraws
    // starting from zero creates overwrites - but I can't start from 1 or border=1 cannot render.
    for($xrad = 0 ; $xrad <= $border_radius; $xrad ++ ){
      for($yrad = 0 ; $yrad <= $border_radius; $yrad ++ ){
        // Attempt to ROUND the corners a little (using pythagoras). This check will avoid the worst of the blocky corners
        if ( ($xrad + $yrad > 0) &&  (pow($xrad, 2) + pow($yrad, 2)) <= pow($border_radius, 2)) {
          foreach(array(1, -1) as $xdir){
            foreach(array(1, -1) as $ydir){
              imagettftext($im, $fontsize, $angle, $x + ($xdir * $xrad), $y + ($ydir * $yrad), $border_color, $fontfile, $line); 
            }
          }
        }
      }
    }
  }

  // Actual Text
  imagettftext($im, $fontsize, $angle, $x, $y, $text_color, $fontfile, $line); // Text
}