Perl Graphics Programming

PostScript in a Nutshell

PostScript is a page description language. A PostScript file is simply a text file that contains the PostScript code to draw one or more page. This file is sent to a PostScript interpreter, which executes the program and draws the pages. In most applications, the PostScript interpreter is embedded in the output device; a laser printer, for example, has a built-in PostScript interpreter that renders the final pages.

For PostScript development work there is also the Ghostscript package, available for most operating systems, which consists of a number of PostScript rendering tools, including an interpreter and a PostScript viewer. Ghostscript is used by many of the software packages in this book (such as the Gimp and ImageMagick) for parsing and generating PostScript, EPS, and PDF files. It also comes as a standard part of most Linux distributions (see the sidebar Getting Ghostscript).

Getting Ghostscript

Ghostscript is a free PostScript interpreter. There are actually two different versions of Ghostscript: the Aladdin Systems distribution and the GNU distribution. The distinction is in the licensing; the Aladdin Free Public License allows the free use and redistribution of the Ghostscript source code, but does not allow the free commercial distribution of the code. The GNU distribution is covered by the GNU General Public License, which allows commercial distribution as part of an open source package. The GNU distribution generally lags behind the Aladdin distribution ...