PHP Script that generates a JPG

imageGenerator.php

<?php 

//
// Creates a JPG of the given size and with the given text in 
// the center.
//

// parameters
// TODO: Is this secure enough?
$text = $_REQUEST['t'];
$width = $_REQUEST['w'];
$height = $_REQUEST['h'];
$fontSize = 5;

// add a little variety
$adjust = intval($text) * 8;

//Create the image resource 
$image = ImageCreate($width, $height);  

//We are making three colors, white, black and gray 
$white = ImageColorAllocate($image, 255, 255, 255); 
$black = ImageColorAllocate($image, 0, 0, 0); 
$blue = ImageColorAllocate($image, 0, 51, 0 + $adjust); 
$grey = ImageColorAllocate($image, 204, 204, 204); 

// draw a black background
ImageFill($image, 0, 0, $blue); 

// draw the text in the center
$textWidth = imagefontwidth($fontSize)*strlen($text); 
$textHeight = imagefontheight($fontSize); 
$vCenter = ceil($height / 2); 
$hCenter = ceil($width / 2); 
$x = $hCenter - (ceil($textWidth/2)); 
$y = $vCenter - (ceil($textHeight/2)); 

ImageString($image, $fontSize, $x, $y, $text, $white);

// draw an offset border
ImageRectangle($image, 1, 1, $width - 2, $height - 2, $white);

// generate the image
header("Content-Type: image/jpeg"); 
ImageJpeg($image); 
ImageDestroy($image); 

?>