<?php

function rotate_square($arr) {
  $fontfile = '/usr/share/fonts/TTF/DejaVuSansMono.ttf';
  $fontsize = 12.0;

  $rowstrs = $rowheights = array();
  $maxwidth = $totalheight = 0;
  foreach ($arr as $row) {
    $rowstrs[] = $rowstr = implode(' ', $row);
    if (($bbox = imagettfbbox($fontsize, 0.0, $fontfile, $rowstr)) !== FALSE) {
      $width = abs($bbox[4] - $bbox[0]);
      if ($width > $maxwidth) $maxwidth = $width;
      $height = abs($bbox[5] - $bbox[1]);
      $rowheights[] = $height;
      $totalheight += $height;
    } else {
      return FALSE;
    }
  }
  $sidelen = max($maxwidth, $totalheight);
  if (($im = imagecreatetruecolor($sidelen, $sidelen)) === FALSE)
     return $im;
  $white = imagecolorallocate($im, 255, 255, 255);
  $black = imagecolorallocate($im, 0, 0, 0);
  imagefilledrectangle($im, 0, 0, $sidelen - 1, $sidelen - 1, $white);
  $i = $totalheight = 0;
  foreach ($arr as $row) {
    imagettftext($im, $fontsize, 0.0, 0, $totalheight, $black, $fontfile, $rowstr[$i]);
    $totalheight += $rowheights[$i];
    $i++;
  }
  $imr = imagerotate($im, 270.0, $white);
  imagedestroy($im);
  return $imr;
}

$m = array(array(1, 0, 0),
           array(0, 1, 0),
           array(0, 0, 1));
$result = rotate_square($m);
if ($result !== FALSE) {
  header('Content-Type: image/png');
  imagepng($result);
  imagedestroy($result);
}