Ghostscript is a package of software that provides:
- An interpreter for the PostScript (TM) language, with the ability to convert PostScript language files to many raster formats, view them on displays, and print them on printers that don't have PostScript language capability built in;
- An interpreter for Portable Document Format (PDF) files, with the same abilities;
- The ability to convert PostScript language files to PDF (with some limitations) and vice versa; and
- A set of C procedures (the Ghostscript library) that implement the graphics and filtering (data compression / decompression / conversion) capabilities that appear as primitive operations in the PostScript language and in PDF.
Ghostscript is written entirely in C, with special care taken to make it run properly on a wide variety of systems, including MS Windows, Apple MacOS, the wide variety of Unix and Unix-like platforms and VMS systems.
Ghostscript is a copyrighted work; it is not shareware or in the public domain.
Versions entitled GPL Ghostscript are distributed with the GNU Affero General Public License, which allows free use, and free copying and redistribution under certain conditions (including, in some cases, commercial distribution). A supported commercial version is available from Artifex Software Inc.
Releases made prior to 2004 were part of the GNU project and were titled GNU Ghostscript; that project now maintains a fork. Versions prior to 8.54 were released first under a more restrictive license as AFPL Ghostscript.
The Ghostscript source code distribution, and the Ghostscript executable code, include the following libraries obtained from other parties:
- The Independent JPEG Group (IJG) library. The executable versions of Ghostscript are based in part on the work of the Independent JPEG Group. For more information, please see the file jpeg.mak in the main Ghostscript source directory, and the README file in the jpeg subdirectory of the Ghostscript source code.
- The PNG library created by Dave Martindale, Guy Eric Schalnat, Paul Schmidt, and Tim Wegner, of Group 42, Inc. For more information, please see the libpng.mak file in the main Ghostscript source directory, and the files readme.txt and png.h in the libpng subdirectory of the Ghostscript source code.
- The zlib library created by Jean-loup Gailly and Mark Adler. For more information, please see the zlib.mak file in the main Ghostscript source directory, and the README file in the zlib subdirectory of the Ghostscript source code.
These libraries do not fall under either the GNU License or the Aladdin Ghostscript Free Public License; they come with their own licenses, which also allow free use and redistribution under appropriate circumstances and which appear in the files referenced just above. These libraries are entirely original works of their respective authors, and are provided "AS IS" with NO WARRANTY and NO SUPPORT.