Ghostscript can be used as a raster image processor for raster computer printers—for instance, as an input filter of line printer daemon—or as the RIP engine behind PostScript and PDF viewers. Ghostscript can also be used as a file format converter, such as PostScript to PDF converter. The ps2pdf conversion program, which comes with the ghostscript distribution, is described by its documentation as a "work-alike for nearly all the functionality of Adobe's Acrobat Distiller product". This converter is basically a thin wrapper around ghostscript's pdfwrite output device, which supports PDF/A-1 and PDF/A-2 as well as PDF/X-3 output. Ghostscript can also serve as the back-end for PDF to raster image converter; this is often combined with a PostScript printer driver in "virtual printer" PDF creators. As it takes the form of a language interpreter, Ghostscript can also be used as a general purpose programming environment. Ghostscript has been ported to many operating systems, including Unix-like systems, classic Mac OS, OpenVMS, Microsoft Windows, Plan 9, MS-DOS, FreeDOS, OS/2, Atari TOS and AmigaOS.
History
Ghostscript was originally written by L. Peter Deutsch for the GNU Project, and released under the GNU General Public License in 1986. Later, Deutsch formed Aladdin Enterprises to dual-license Ghostscript also under a proprietary license with an own development fork: "Aladdin Ghostscript" under the Aladdin Free Public License and "GNU Ghostscript" distributed with the GNU General Public License. With version 8.54 in 2006, both development branches were merged again, and dual-licensed releases were still provided. Ghostscript is currently owned by Artifex Software and maintained by Artifex Software employees and the worldwide user community. According to Artifex, as of version 9.03, the commercial version of Ghostscript can no longer be freely distributed for commercial purposes without purchasing a license, though the GPL variant allows commercial distribution provided all code using it is released under the GPL. Artifex's point of view on "aggregated software" was challenged in court for MuPDF. In February 2013, Ghostscript changed its license from GPLv3 to GNU AGPL in version 9.07, which raised license compatibility questions for example by Debian.
Variants and forks
Aladdin Ghostscript 5.50 and 6.01
AFPL Ghostscript is Aladdin Ghostscript under the AFPL, 6.50 to 8.54, now abandoned.
There are several sets of free fonts supplied for Ghostscript, intended to be metrically compatible with common fonts attached with the PostScript standard. These include:
35 basic PostScript fonts contributed by URW++ Design and Development Incorporated, of Hamburg, Germany in 1996 under the GPL and AFPL. It is a full set fonts similar to the classic Adobe set: Bookman L, Century Schoolbook L, Chancery L, Dingbats, Gothic L, Nimbus Mono L, Nimbus Roman No9 L, Nimbus Sans L, Palladio L, Standard Symbols L, in Type1, TrueType, and OpenType formats.
The GhostPDL package includes additional fonts under the AFPL which bars commercial use. It includes URW++ versions of Garamond, Optima, Arial, Antique Olive, and Univers, Clarendon, Coronet, Letter Gothic, as well as URW Mauritius and a modified form of Albertus known as A028. Combined with the base set, they represent a little more than half of the standard PostScript 3 font complement.
A miscellaneous set including Cyrillic, kana, and fonts derived from the free Hershey fonts, with improvements by Thomas Wolff.
The Ghostscript fonts were developed in the PostScript Type 1 format but have been converted into the TrueType format, usable by most current software, and are popularly used within the open-source community. The Garamond font has additionally been improved upon. URW's core 35 fonts have been subsequently incorporated into GNU FreeFont and TeX Gyre.
