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. It can also be used as a file format converter, such as PostScript to PDF converter. The codice_1 conversion program comes with the ghostscript distribution.
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-like systems, classic Mac OS, OpenVMS, Microsoft Windows, Plan 9, MS-DOS, FreeDOS, OS/2, ArcaOS, Atari TOS, RISC OS 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 (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. 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 (A)GPL variant allows commercial distribution provided all code using it is released under the (A)GPL.
In February 2013, with version 9.07, Ghostscript changed its license from GPLv3 to GNU AGPL. which raised license compatibility questions, for example by Debian.
Front ends.
Ghostscript graphical user interfaces (GUIs) view PostScript or PDF files on screens, scroll, page forward, page backward, zoom text, and print pages. Such GUIs include Evince, IrfanView, Inkscape and PDF24 Creator. Virtual printers can also create PDF files.
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. These include:
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 often 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.