Encapsulated PostScript (EPS) is a Document Structuring Convention (DSC) conforming

PostScript PostScript (PS) is a page description language in the electronic publishing and desktop publishing realm. It is a dynamically typed, concatenative programming language. It was created at Adobe Systems by John Warnock, Charles Geschke, Doug Br ...

document format usable as a

graphics file format An Image file format is a file format for a digital image. There are many formats that can be used, such as JPEG, PNG, and GIF. Most formats up until 2022 were for storing 2D images, not 3D ones. The data stored in an image file format may b ...

. The format was developed as early as 1987 by

John Warnock John Edward Warnock (born October 6, 1940) is an American computer scientist and businessman best known for co-founding Adobe Systems Inc., the graphics and publishing software company, with Charles Geschke. Warnock was President of Adobe for ...

and Chuck Geschke, the founders of

Adobe Adobe ( ; ) is a building material made from earth and organic materials. is Spanish for ''mudbrick''. In some English-speaking regions of Spanish heritage, such as the Southwestern United States, the term is used to refer to any kind of e ...

, together with

Aldus Aldus may refer to: People * Aldus Manutius, a Venetian publisher who popularized small personal volumes * Aldus Manutius the Younger, grandson of Aldus Manutius Businesses * Aldine Press, the printing office founded by Aldus Manutius * Aldus Cor ...

. The basis of early versions of the Adobe Illustrator Artwork file format is formed by EPS together with the DSC Open Structuring Conventions. EPS files are more-or-less self-contained, reasonably predictable, PostScript documents that describe an image or drawing and can be placed within another PostScript document. An EPS file is essentially a PostScript program, saved as a single file that includes a low-resolution preview "encapsulated" within it, allowing some programs to display a preview on the screen. An EPS file contains a '' BoundingBox'' DSC comment, describing the rectangle containing the image described by the EPS file. Applications can use this information to lay out the page, even if they are unable to directly render the PostScript inside.

Previews

EPS files frequently include a preview picture of the content for on-screen display. The idea is to allow a simple preview of the final output in any application that can draw a bitmap. Without this preview, the applications would have to directly render the PostScript (PS) data inside the EPS, which was beyond the capabilities of most machines that used PostScript. When EPS was first implemented, the only machines widely using PostScript were

Apple Macintosh The Mac (known as Macintosh until 1999) is a family of personal computers designed and marketed by Apple Inc. Macs are known for their ease of use and minimalist designs, and are popular among students, creative professionals, and software en ...

es. These machines could not directly render the PostScript, which presented

with the dilemma of how to provide a preview image for the designer while also including the PS version for the printer. On the Mac this turned out to be easy to solve, as the Mac file system includes two parts (known as ''forks'') that are logically referred to as one file. By placing the PostScript in the data fork and a standard Mac

PICT The Picts were a group of peoples who lived in what is now northern and eastern Scotland (north of the Firth of Forth) during Late Antiquity and the Early Middle Ages. Where they lived and what their culture was like can be inferred from ear ...

resource in the

resource fork The resource fork is a fork or section of a file on Apple's classic Mac OS operating system, which was also carried over to the modern macOS for compatibility, used to store structured data along with the unstructured data stored within the data f ...

, both images could be moved about together invisibly as if they were one file. While a PICT preview often contains a

bitmap In computing, a bitmap is a mapping from some domain (for example, a range of integers) to bits. It is also called a bit array A bit array (also known as bitmask, bit map, bit set, bit string, or bit vector) is an array data structure that c ...

, it could also contain a vector representation of the whole image, providing very high quality previews. Neither of these technologies is commonly used on any other operating system, however. When faced with the same problems on

Microsoft Windows Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for serv ...

-based versions of their programs, Adobe chose to instead add a

TIFF Tag Image File Format, abbreviated TIFF or TIF, is an image file format for storing raster graphics images, popular among graphic artists, the publishing industry, and photographers. TIFF is widely supported by scanning, faxing, word processin ...

file encoded into the header section of the PostScript. Sometimes, although more rarely, they used the WMF (''

Windows Metafile Windows Metafile (WMF) is an image file format originally designed for Microsoft Windows in the 1990s. The original Windows Metafile format was not device-independent (though could be made more so with placement headers) and may contain both vector ...

'') format instead. WMF has the potential to provide vector previews, similar to PICT on the Mac. Both of these PC format EPS files have a particular disadvantage: because the PostScript data, header, and preview are all in the same file, they will cause printing errors if a program does not understand the format well enough to extract only the PostScript data. A fourth format known as a ''EPSI'' includes an

ASCII ASCII ( ), abbreviated from American Standard Code for Information Interchange, is a character encoding standard for electronic communication. ASCII codes represent text in computers, telecommunications equipment, and other devices. Because of ...

-encoded preview bitmap. This format allows for black-and-white previews only. It is mainly used on

Unix-like A Unix-like (sometimes referred to as UN*X or *nix) operating system is one that behaves in a manner similar to a Unix system, although not necessarily conforming to or being certified to any version of the Single UNIX Specification. A Unix-li ...

systems. Unfortunately, with several different ways of representing the preview, they have limited portability. An application that is unable to interpret an EPS file's preview will typically show an empty box on screen, but it will be able to print the file correctly. The most widely supported kind of preview is a Windows format preview with a TIFF.

Vulnerability

Due to the ability to use embedded scripts,

Microsoft Microsoft Corporation is an American multinational technology corporation producing computer software, consumer electronics, personal computers, and related services headquartered at the Microsoft Redmond campus located in Redmond, Washing ...

removed support for EPS files in

Microsoft Office Microsoft Office, or simply Office, is the former name of a family of client software, server software, and services developed by Microsoft. It was first announced by Bill Gates on August 1, 1988, at COMDEX in Las Vegas. Initially a marketin ...

programs in May 2018.

Previews

Vulnerability

See also

References

Further reading