Chapter 15. Creating GIF images

PHP is not limited to creating just HTML output. It can also be used to create GIF image files, or even more convenient GIF image streams. You will need to compile PHP with the GD library of image functions for this to work.

Example 15-1. GIF creation with PHP 1  2 <?php 3  Header("Content-type: image/gif"); 4  $string=implode($argv," "); 5  $im = imagecreatefromgif("images/button1.gif"); 6  $orange = ImageColorAllocate($im, 220, 210, 60); 7  $px = (imagesx($im)-7.5*strlen($string))/2; 8  ImageString($im,3,$px,9,$string,$orange); 9  ImageGif($im); 10  ImageDestroy($im); 11 ?> 12

This example would be called from a page with a tag like: <img src="button.php3?text"> The above button.php3 script then takes this "text" string an overlays it on top of a base image which in this case is "images/button1.gif" and outputs the resulting image. This is a very convenient way to avoid having to draw new button images every time you want to change the text of a button. With this method they are dynamically generated.