Draw a dashed line in PHP

<?php//from w w w  . j  a  va 2s  . c o m
// Create a 100x100 image
$im = imagecreatetruecolor(100, 100);
$white = imagecolorallocate($im, 0xFF, 0xFF, 0xFF);

// Draw a vertical dashed line
imagedashedline($im, 50, 25, 50, 75, $white);

// Save the image
imagepng($im, './dashedline.png');
imagedestroy($im);
?>