Ghostscript

Ghostscript is a suite of software based on an interpreter for Adobe Systems' PostScript and Portable Document Format (PDF) page description languages. Its main purposes are the rasterization or rendering of such page description language files, for the display or printing of document pages, and the conversion between PostScript and PDF files.

Features

Ghostscript can be used as a raster image processor (RIP) 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 (but not the user interface) of Adobe's Acrobat Distiller product".^[3] 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.^[3]

Ghostscript can also serve as the back-end for PDF to raster image (png, tiff, jpeg, etc.) 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, Linux, 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^[4] (which, despite the name, is not a free software license, as it forbids commercial distribution) and "GNU Ghostscript" distributed with the GNU General Public License.^[5] In 2006 with version 8.54 both the development branches were merged again, while still provided dual-licensed.^[6] 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 (A)GPL variant allows commercial distribution provided all code using it is released under the (A)GPL.^[7] Artifex' point of view on "aggregated software" was challenged in court for MuPDF.^[8][9][10]

In February 2013 Ghostscript changed its license from GPLv3 to AGPLv3^[11][12] which raised license compatibility questions for example by Debian.^[13]

Variants and forks

• AGPL Ghostscript is the canonical variant available, since February 2013,^[11] under the Affero General Public License which is a free software license.
• GNU Ghostscript is part of the GNU project and is now derived from GPL Ghostscript.
• ESP Ghostscript was distributed by Easy Software Products under the GPL. It was based on GPL Ghostscript and contains several modifications to improve compatibility with ESP's Common Unix Printing System. This version is no longer developed, since it was merged with GPL Ghostscript.^[14]
• Ghostscript is the current commercial proprietary version licensed by Artifex Software for inclusion in closed-source products.
• Ghost Trap is a variant of GPL Ghostscript secured and sandboxed using Google Chrome's sandbox technology.
• Aladdin Ghostscript was before June 2006 the leading edge of Ghostscript development and distributed as AFPL Ghostscript under the Aladdin Free Public License. AFPL Ghostscript is now abandoned.^[15]

The GPL version is also used as the basis for a Display Ghostscript, which adds the functionality needed to fully support Display PostScript.

Front ends

Several graphical user interfaces have been written for use with Ghostscript which permit a user to view a PostScript or PDF file on screen, scroll, page forward and backward, and zoom the text as well as print single or multiple pages.

• Evince under Unix and Windows. Uses the libspectre library to render postscript, which in turn needs libgs from ghostscript. The current Windows package of Evince comes with libgs version 8.
• Ghostview runs under Unix/X11.
• GSview runs under Microsoft Windows, OS/2, and Unix-like operating systems. It is best known in its Windows and OS/2 versions. On UNIX it uses the GTK+ toolkit. Although released under Aladdin Free Public Licence, it also employs a nag screen to urge users to register so as to support the development of GSview. The registration fee is A$40. GSview is copyrighted to a different company than ghostscript, namely Ghostgum Software.^[16] The Ghostscript documentation states, concerning its installation under Windows: "After installing Ghostscript, it is strongly recommended that you install the GSview previewer, which provides an easier to use graphical interface for Ghostscript."^[17]
• gv runs under Unix/X11 and VMS. gv is a visually improved version of Ghostview. Its behaviour is similar to Ghostview.
• KGhostView runs under Unix/X11. It is a KDE3 port of Ghostview.
• mgv runs under Unix/X11. It is a Motif based front-end to Ghostscript. It features a more conventional user interface, with regular menus, a toolbar, and scrollbars.
• Moonshiner is a graphical front-end for using Ghostscript to convert from PostScript to PDF, aiming to be a Linux work-alike for Adobe's Distiller.
• Okular runs under Unix/X11 and Microsoft Windows (using KDE4 for Windows). It is a KDE4 application.
• PDF Blender is a cross-platform application that converts and merges documents to and from PostScript and PDF formats.
• PS_View runs under Windows, Linux and Mac OS X; it is included in TeX Live as the default PostScript viewer on Windows.^[18]
• Ghostscript Studio runs under Windows. It is graphical front-end for using Ghostscript to convert between various formats, view PDF and multi-page PostScript files.

A number of applications use Ghostscript to import or display PDF files (e.g., IrfanView, Inkscape). Additionally, a large number of virtual printers use Ghostscript to create PDF files; for a non-exhaustive list, see List of virtual printer software.

Wrappers

Libraries that provides ability to access Ghostscript library from various programming languages.

• Ghostscript.NET .NET Ghostscript library wrapper written in C#.

Free fonts

There are several sets of free fonts supplied for Ghostscript, intended to be metrically compatible with common fonts attached with the PostScript standard.^{[19][20][21][22][23]} These include:

• 35 basic PostScript fonts contributed by URW++ Design and Development Incorporated, of Hamburg, Germany in 1996 under the GPL and AFPL.^{[24][25][26][27][28][29]} It is a full set of Type1 fonts similar to the classic Adobe set: Bookman L (Bookman), Century Schoolbook L (New Century Schoolbook), Chancery L (Zapf Chancery), Dingbats (Zapf Dingbats), Gothic L (Avant Garde), Nimbus Mono L (Courier), Nimbus Roman No9 L (Times), Nimbus Sans L (Helvetica), Palladio L (Palatino), Standard Symbols L (Symbol).
• The GhostPDL package (including Ghostscript as well as companion implementations of HP PCL and Microsoft XPS) includes additional fonts, including URW++ versions of Garamond (Garamond No. 8), Optima (URW Classico), Arial, Antique Olive, and Univers (U001), as well as URW Mauritius (similar in style to the Postscript Marigold font but older) 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 (such as adding accented characters).

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.^[30][31]

See also

• Common Unix Printing System
• Foomatic
• PostScript Printer Description
• Printer driver
• pstoedit

References

External links

• Homepage