gistfile1.php

function calculateTextBox($text, $fontFile, $fontSize, $fontAngle) {
  $boundingbox = imageTTFBbox($fontSize, $fontAngle, $fontFile, $text);
  $minX = min(array($boundingbox[0], $boundingbox[2], $boundingbox[4], $boundingbox[6]));
  $maxX = max(array($boundingbox[0], $boundingbox[2], $boundingbox[4], $boundingbox[6]));
  $minY = min(array($boundingbox[1], $boundingbox[3], $boundingbox[5], $boundingbox[7]));
  $maxY = max(array($boundingbox[1], $boundingbox[3], $boundingbox[5], $boundingbox[7]));

  return array(
    "left" => abs($minX) - 1,
    "top" => abs($minY) - 1,
    "width" => $maxX - $minX,
    "height" => $maxY - $minY
  );
}