Draw a dashed line with alternative to imagedashedline() in PHP

<?php//  ww w. j  av a  2 s  .  c  om
// Create a 100x100 image
$im = imagecreatetruecolor(100, 100);
$white = imagecolorallocate($im, 0xFF, 0xFF, 0xFF);

// Define our style: First 4 pixels is white and the
// next 4 is transparent. This creates the dashed line effect
$style = Array(
                $white,
                $white,
                $white,
                $white,
                IMG_COLOR_TRANSPARENT,
                IMG_COLOR_TRANSPARENT,
                IMG_COLOR_TRANSPARENT,
                IMG_COLOR_TRANSPARENT
                );

imagesetstyle($im, $style);

// Draw the dashed line
imageline($im, 50, 25, 50, 75, IMG_COLOR_STYLED);

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