Introduction

PHP, or PHP Hypertext Pre-processor, is one of the most popular scripting languages available to web developers. There are many reasons why PHP is now the most popular server-side scripting language for the Apache web server. Firstly, it supports database connectivity to a huge number of popular vendors, including Microsoft, Oracle and IBM. Secondly, with the correct libraries installed, PHP also supports real-time generation of images, PDF files, and even shockwave movie files! The only limit that bounds us when we’re developing with PHP is our imagination.

For developers like myself, one of the most popular features of PHP is real-time image generation. That is, we can create a new image canvas, “paint” it, and either save it to a file, or send it directly to the browser. In this article, I will show you how to create an image in real-time with PHP. The image will be similar to the ones used on yahoo.com and paypal.com, where a random number is generated inside of an image. That image is displayed in the browser, and you have to enter that random number into a text box to create a new account. This is a method that is becoming more popular, and it’s used to stop people from generating multiple user accounts in one go, which, is some cases, can crash the web server(s).

To handle the code described in this article, you should feel comfortable with the PHP scripting language at an intermediate level. Also, if you haven’t got the necessary libraries to generate images installed (explained in a minute), then you should be able to modify the php.ini file. In our example, we will be using PHP on a Windows 2000 machine running Apache (You can download apache for Linux or Windows from http://php.weblogs.com/apache_windows).

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