From access counters and log-report graphs to scientific plots and on-the-fly animated GIFs, graphics scripting is within the grasp of most Web authors. It is a little documented field, however, and the many valuable free libraries and tools available on the Internet remain under-utilized. Programming Web Graphics with Perl & GNU Software is aimed at intermediate and advanced Web users who want to use CGI scripts to generate dynamic graphic content. It will also help to demystify the manipulation of graphics formats for newcomers to the Web.

Programming Web Graphics with Perl & GNU Software takes a practical, resource-like approach to the content. It is not a book about design or aesthetics of Web graphics; its focus is on programming or, more accurately, scripting programs that manipulate graphics file to be published on the Web. Most of the examples in the book use Perl as a scripting language, though the concepts are applicable to any programming language. However, several powerful Perl modules for generating graphics (GD, PerlMagick, GIFgraph) should help position Perl as a major contender for your Web graphics applications. Most of the topics covered in the book are applicable to any platform (NT, Linux, Un*x, MaxOS), with the exception of the chapter detailing the Gnu Image Manipulation Program (a free Adobe Photoshop-like application), which requires a connection to an X server. The focus is always on free software, when it is available.

This book covers the following:

• a tour through the most popular Web graphics file formats by implementing parsers for GIF, JPEG, and PNG files
• descriptions of the PNG, JPEG, and giflib libraries, as well as many other free and proprietary libraries and SDKs
• extensive documentation and examples using the Perl graphics modules GD and GIFgraph, and the Perl interface to the powerful ImageMagick libraries
• documentation on the Gnu Image Manipulation Program (GIMP) and the Perl interface that lets you easily script plug-ins or interface to the GIMP via the Web
• the creation of image maps from data extracted from a database
• the implementation of several new Perl modules for the creation of neatly formatted PostScript files
• details on interfacing to a fax gateway
• reusable recipes for many popular applications such as Web counters and Web cams
• the creation of animated GIFs on-the-fly

One of the key ingredients to the success of the Web is that anyone who wanted to could participate in publishing to the world. This book will take its readers to the next level of publishing to the world: learning to use scripting programs to create dynamic graphics for their Web sited. The information in this book is written in a practical, easy manner with high-quality documentation and useful examples throughout. It is a detailed reference that provides Web designers and programmers and with the information they need to program.