Ghostscript for PDF

Ghostscript is a suite of software based on an interpreter for Adobe Systems' PostScript and Portable Document Format (PDF) page description languages.

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; 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, OS/2 and AmigaOS.

Frontends

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.

• Ghostview runs under Unix/X11. Ghostview has an unusual (and arguably counter-intuitive) user interface feature: dragging the mouse over the image pans the image in the opposite direction (the mouse moves the viewport over the image, rather than the image underneath the viewport). The effect is similar to having invisible scroll bars all over the image and is approximately the opposite of panning in Google Maps and other applications.
• gv runs under Unix/X11. gv is a visually improved version of Ghostview. Its behaviour is similar to 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.
• GSview runs under Microsoft Windows, OS/2, and UNIX-like operating systems. It is best known for its Windows and OS/2 versions. On UNIX it uses the GTK+ toolkit.
• PDF Blender is a cross-platform application that converts and merges documents to and from postscript and pdf formats.

• Although under a public license, GSview also employs a nag screen to urge users to register so as to support the development of GS. The registration fee is AUD$40.

History

Ghostscript was originally written by L. Peter Deutsch in 1986 for the GNU Project, and released under the GNU General Public License; later, Deutsch formed Aladdin Enterprises to license Ghostscript under a proprietary license. Ghostscript is currently owned by Artifex Software and maintained by Artifex Software employees and the world-wide user community. Current version of Ghostscript is again available under GPL but can be also licensed for use in proprietary projects for a fee. 

Variants of Ghostscript

• GPL Ghostscript is the canonical variant available under the GNU General Public License, which is a free software license. Before June 2006, the leading edge of Ghostscript development was distributed as AFPL Ghostscript (formerly named Aladdin Ghostscript) under the Aladdin Free Public License, which restricts commercial use. AFPL Ghostscript is now abandoned.^[2]
• 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.^[3]
• Ghostscript is the current commercial proprietary version licensed by Artifex Software for inclusion in closed-source products.

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

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